PATHOLOGY AND INTERVENTION

IN MUSCULOSKELETAL REHABILITATION THIS PAGE INTENTIONALLY LEFT BLANK PATHOLOGY AND INTERVENTION IN MUSCULOSKELETAL REHABILITATION

Editors David J. Magee, PT, PhD Professor and Associate Dean Department of Physical Therapy Faculty of Rehabilitation Medicine University of Alberta Edmonton, Alberta, Canada

James E. Zachazewski, PT, OPT, SCS, ATC Clinical Director Physical Therapy Massachusetts General Hospital Boston, Massachusetts

William S. Quillen, PT, PhD, SCS, FACSM Professor Associate Dean, College of Medicine Director, School of Physical Therapy and Rehabilitation Sciences University of South Florida Tampa, Florida

Editorial Consultant Bev Evjen Swift Current, Saskatchewan, Canada

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PATHOLOGY AND INTERVENTION IN MUSCULOSKELETAL REHABILITATION ISBN: 978- 1-4160-0251-2

Copyright © 2009 by Saunders, an imprint of Elsevier Inc. Photo Copyright © 2009 for Chapter 8 and Chapter 14, will be retained by Diane Lee Photo Copyright © 2009 for Chapter 8 and Chapter 14, will be retained by Linda-Joy Lee

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Introduction is seen in the bony attachments of the medial meniscus. Bedet and Fowler3 have described fo ur types of anterior Injuries to the ar ticular cartilage and the meniscus of the horn meniscal attachments, three of which attached to knee are commo n. They can be caused by work activities bone. The type fo ur variant had no firm bony attachment , and athletic injuries as well as activities of daily living and but this type was fo und in only one of 34 specimens . A sim­ degeneration. They can occur as isolated injuries or in com­ ilar attachme nt was described by Nelson and LaPrade;4 14% bination with injury to ligaments and other knee structures . of their specimens had no direct bony att achment of the Me niscal tears and chondral injuries can cause significant anterior horn. The remainder of the medial meniscus is clinical symptoms of pain, swelling, loss of motion, and att ached to the knee joint capsule . The capsular attachment locking, often requiring surgical intervent ion. Arthroscopic of the meniscus to the tibia is called the coronary ligament. treatment of meniscal tears has become one of the most The posterior bony attachment consiste ntly lies anterior to l common procedures in the United States . the tibial insertion of the posterior cruciate ligament. John­ To evaluate and treat these injuries, the clinician must son et al .5 studied the surface area of t11e meniscal bony have an understanding of the anatomy, histology, and func­ attachments and fo und that the anterior horn of the medial tio n of the meniscus and articular cartilage . This chapter meniscus has the largest fo otprint (61.4 mm2 ), and the reviews the anatomy and histology of both the articular car­ posterior horn of the lateral meniscus has the smallest 2 tilage and the meniscal cartilage and the signs and symp­ (28.5 mm ) (Figure 17-1). toms of injuries to these structures; diagnostic studies and The lateral meniscus, which is more semicircular in treatment alternatives are then discussed . shape, also has anterior and posterior bony attachments . The lateral meniscus covers a larger area of the tibial articu­ Meniscus lar sur face than the medial meniscus . A lateral disc-shaped or discoid meniscus that covers the entire tibial articular Anatomy sur face has been reported in 3.5% to 5% of cases 6 Discoid The me niscus was first described by Bland -Sutton2 in 1897 menisci are the result of a developmental anomaly and as "the fu nctionless remnants of intra-articular leg mus­ may have a fam ilial pattern; they are rarely fo und medially, c1es ." Since that time, the meniscal anatomy has been stud­ are generally thicker than normal, and lack normal poste­ ied extensively . From a gross anatomical perspective , the rior attachments . The bony att achment sites of the nor­ menisci are two fibrocartilaginous structures that have mally shaped lateral meniscus, the anterior and posterior strong bony attachments to the anterior and posterior tibial horns, are much closer together in the lateral meniscus t1un plateau . in the medial meniscus . The anterior horn attaches just In the C-shaped medial meniscus, the anteroposterior adjacent to the anterior cruciate ligament (ACL). The bony dime nsion of the posterior horn is larger than the antero­ attachment site of the posterior horn is located behind the posterior dimension of the anterior horn. Some variation tibial spines and anterior to the insertion site of t11e medial

579 580 CHAPTER 17 • Injuries to the Meniscus and Articular Cartilage

Blood Supply

The entire meniscus is vascular at the time of birth . By 9 months of age , the inner one third has become avascular. The vascularity of the meniscus decreases until approximately age 10, at which time it reaches its ad ult condition. Te n per­ cent to 25% of the lateral meniscus is vascular, and 10% to 30% of the medial meniscus is vascular (Figures 17-3 Medial and 17-4).8 The vascular supply of the menisci is the superior and inferior branches of the medial and lateral genicular arteries . These vessels form a perime niscal capillary plexus . Ligament of Wrisberg The region of the popliteal hiatus is a relatively avascular Posterior cruciate ligament zone of the lateral me niscus. Cell nutrition to the inner Figure 17-1 70% to 90% of the menisci comes from diffusion or Anatomy of th e menisci. (From Warren R, Arnoczky SP, Wickiewicz mechanical pumping.9 TL: Anatomy of the knee. In Nicholas JA, Hershamn EE, eds: The IOlJler extremity and spine in sports medicine, p 687, St. Louis, 1986, Mosby. ) Innervation

The menisci are innervated by myelinated and unmyeli n­ ated nerve fibers . Neural elements are most ab undant in the outer portion of the meniscus . The anterior and poste­ meniscus . The Wrisberg variant of the discoid meniscus rior horns of the meniscus are innervated with mechanore­ lacks a posterior bony attachment, which leaves the poste­ ceptors th at may play a role in proprioceptive feedback in rior meniscofemoral ligament of Wrisberg as the only pos­ the knee .lo terior st abilizing structure; this often allows excess motion and posterior horn instability. The anterior meniscofemoral Function ligament of Humphry runs from the posterior horn of the lateral meniscus to the posterior cruciate ligament and The menisci are critical structures in the knee . They take femur. In the posterolateral corner of the knee, the popli­ load from the femur and distribute it over the entire te us tendon lies between the knee joint capsule and the lat­ articular surface of the tibial plateau. The me nisci trans­ eral meniscus . This region is called the popliteal hiatus. mit at least 50% to 70% of the load when the knee is in Attachments also are fo und between the tibia and meniscus extension. Lo ad transmission increases to 85% at 90° flex­ through the capsule, but these are not as well developed as ion .11 Radin et al .12 showed that removal of the medial on the medial side . Because of the differences in the attach­ meniscus results in a 50% to 70% decrease in femoral con­ ment to the tibia, the lateral meniscus has more mobility dyle surface contact area and an increase in joint reactive through knee joint motion (Figure 17-2). Thompson forces of 100%. Total lateral meniscectomy leads to a et al? have demonstrated 11.2 mm of posterior excursion 40% to 50% decrease in contact area and an increase in of the lateral meniscus during knee joint flexion, compared contact stresses of 200% to 300%. ]2·14 In additio n to to 5.2 mm of exc ursion of the medial meniscus . being increased, stresses within the joint are distributed

LM MM MM

LM

11.2 mm A B Figure 17-2 Th e meni sci move anteriorly with extension (A) and posteriorly with flexion (B). The right knee is shown. MM, Medial menisclls; LM, lateral meniscus. (Modified fro m Kapandji IA: Thephysio logy ofthe joints: annotated diagl·ams of the mechanics of the human joints, Edinburgh, 1970, Churchill Livingstone.) Injuries to the Meniscus and Articular Cartilage • CHAPTER 17 581

Shoemaker and Markolf18 demonstrated that the posterior horn of the medial meniscus is the most important struc­ ture in the knee for resisting an anterior tibial force applied to an ACL-deficient knee. The inner two thirds of the menisci are important for shock absorption and for increasing joint contact surface area, and therefore for reducing contact stresses. The peripheral ring of the menisci is important for load trans­ mission, shock absorption, and knee stability.

Functions of the Menisci

• Load sharing • Reducing joint contact stresses (by increasing contact surface area) figure 17-3 • Shock absorption Blood supply of the meniscus. Staining studies demonstrate vascular • Passive joint stabilization network within the meniscus that is critical fo r potential fo r healing. • Limiting extremes of flexion and extension (From Arnoczky SP, Warren RF: Microvascu lature of the human • Proprioception meniscus, Am J Sports Med ]0:90, 1982.)

Epidemiology unevenly, resulting in increased compressive and shear forces across the joint. The mean annual incidence of meniscal tears is 60 to 70 per The meniscus plays an important role in shock absorp­ 100,000/9,20 and the ratio of males to females varies from tion.IS Compression studies using bovine menisci have 2.5:1 to 4:1. Approximately one third of all meniscal tears are demonstrated that articular cartilage is approximately twice associated with a tear in the ACL.21 The peak incidence of as stiff as meniscal fibrocartilage. meniscal tears associated with ACL injury occurs at 21 to The menisci also can play a large role in joint stability.16 30 years of age in males and at 11 to 20 years of age in Medial meniscectomy in a knee with an intact ACL does females. A traumatic cause is more likely in younger patients, not affect knee stability; however, medial meniscectomy whereas older patients are more likely to have degenerative in an ACL-deficient knee results in an increase in anterior meniscal tears. tibial translation of up to 58% at 90° flexion. Allen et al. J 7 Patients with an acute ACL injury are more likely to have a showed that the resultant force in the medial meniscus of lateral meruscal tear than a medial meniscal tear.22 Patients an ACL-deficient knee increased 52% in full extension with chronic ACL-deficient knees, on the other hand, are more and 197% at 60° flexion under a 134 newton (N) load. likely to develop a medial meniscal tear; the role of the medial

figure 17-4 Zone: Red-red Red-white White-white Schematic of me niscus demonstrating three zones with varying degrees of vascularity and potential for healing. (From Insall IN, Scott WN: Surgery of the knee, cd 3, p 476, New York, 2001, Churchill Livingstone.)

Meniscus: Peripheral Central (free edge)

Vascularity: Excellent Variable Poor 582 CHAPTER 17 • Injuries to the Meniscus and Articular Cartilage meniscus as an anteroposterior joint stabilizer in ACL-deficient value. The presence of an ACL injury makes joint line ten­ knees is thought to be the reason for this phenomenon. derness less helpful. Shelbourne et al25 showed an accu­ racy of 54.9% for medial meniscal tears and 53.2% for Diagnosis of Meniscal Tears lateral meniscal tears. Terry et a1.26 examined the accuracy of a thorough history, physical examination, and plain Meniscal tears can be diagnosed through a combination of radiographs to predict meniscal pathology preoperatively. a careful history, a thorough physical examination, and the The overall clinical evaluation had a sensitivity of 95%, a appropriate diagnostic tests. specificity of 72%, and a positive predictive value of 85% for tears of the medial meniscus; it had a sensitivity of History 88%, a specificity of 92%, and a positive predictive value of 58% for tears of the lateral meniscus. All tears were con­ Younger patients usually have a history of a weight-bearing, firmed arthroscopically.26 twisting, or hyperflexion injury. These patients usually present with acute joint line pain and swelling. Loss of extension with a mechanical block (locking) suggests a displaced bucket han­ Diagnosis of Meniscal Pathology dle tear and usually reg uires acute surgical treatment. • History of twisting while weight bearing Patients may complain of catching, popping, or locking. • History of hyperflexion of the knee These symptoms occur with meniscal tears, but they also • Joint line tenderness may be symptoms of chondral injury or patellofemoral • Minimal to moderate synovial swelling chondrosis. Degenerative tears of the meniscus usually • Pain or forced flexion occur in patients over 40 years of age. These tears fre­ • Limited extension with spring block end feel quently present with a traumatic history of swelling and • MagnetiC resonance imaging joint line pain, and they often are associated with some • High level of suspicion degree of chondral damage.

Physical Examination Diagnostic Studies

Whenever the clinician suspects meniscal pathology, a com­ Several types of imaging shlclies can be used as an adjunct to plete physical examination of the low back and lower the history and physical examination. Radiographs, arthro­ extremity must be performed. graphy, magnetic resonance imaging (MRl), and arthros­ Examination of the knee should begin with inspection of copy have all been used to help define meniscal pathology. tlle skin and surrounding tissues. Quadriceps atrophy should be assessed. The knee should be examined for evi­ Radiography deIlCe of an effusion. Range of motion should be assessed Plain radiographic films should be obtained in the evaluation and compared to the opposite side. The ligamentous struc­ of all knee pathology. A standard knee series should include a tures should be tested. The joint should be palpated to posteroanterior/anteroposterior (PA/ AP) weight-bearing assess for joint line tenderness, tenderness at ligamentous view in 30° flexion, a true lateral view, and a tangential image, insertion points, and tenderness in the region of the pes such as a Merchant or skyline view (Figure 17-5). These anserine bursa. The patellofemoral region also should be images will not confirm the diagnosis of a meniscal tear, but palpated. tlley are still important. Plain radiographic films can be used Numerous special tests have been used to assess for to assess tlle knee for joint space narrowing, osteophyte for­ meniscal pathology. Taken in isolation, the various physi­ mation, subchondral cysts, and subchondral sclerosis, all cal examination tests for meniscal tears do not have high findings of osteoarthritis of tlle knee. Early degenerative sensitivities, specificities, or positive predictive values. changes are better seen on PAl AP views in 30° flexion, These tests include joint line palpation, the flexion because degenerative changes usually are more severe on McMurray test, and Apley's grind test. These tests have the posterior femoral condyles tllan on the dis�al femur272, 8 been shown to have mixed results. Evans et al.23 looked Non-weight-bearing radiographic films are not useful for at the flexion McMurray test to determine intraobserver determining joint space narrowing. The tangential view is reliability and accuracy. They found that a medially based best for assessing the patellofemoral joint, which can be a "thud" with rotation and flexion was the only McMurray cause of medial or lateral knee pain. Plain radiographic films sign to correlate with meniscal pathology. This finding can also help determine whether any otller bony pathology had 98% specificity but only 15% sensitivity for medial is present. If any question arises about lower limb alignment, meniscal tears23 Weinstabl et a1.24 found that joint line 3-foot (1.0 m) standing films should be obtained to deter­ tenderness was the best clinical sign of a meniscal tear, mine the anatomical and mechanical axis of the lower with a sensitivity of 74% and a 50% positive predictive extremity. Injuries to the Meniscus and Articular Cartilage • CHAPTER 17 583

Figure 17-5 Standard radiographic views. A, AP weight-bearing view of the knee showing medial joint space loss. B, Lateral radiograph of the knee. C, Tangential view of the patellofemoral joint.

required to obtain the scan; and (3) the tight space in Standard Knee Radiographic Films which the patient must lie unless an open magnet machine is used. Normal menisci appear as low signal intensity on all • PAIAP weight-bearing view in 30° flexion image sequences. • Lateral view • Merchant or skyline view Based on its MRI appearance, the meniscus tear/injury can be categorized according to a fo ur grade system (Figure 17-6). Grade 0 represents a normal meniscus. Grade I and grade II show some degree of intrameniscal Magnetic Resonance Imaging signal, but the signal does not abut the fr ee edge of the MRI has proven to be a great advance in the diagnosis of meniscus. With grade III menisci, the intrameniscal signal knee pathology, but the scans must be read in the context exits through the articular sur face of the meniscus. The of the patient 's history and the phy sical examination find­ grade III pattern is consistent with a meniscal tear.29 ings. Some of the advantages of MRI are (1) it allows the MRI is a power ful tool in the diagnosis of meniscal clinician to see the ligamentous and cartilaginous structures pathology. Several studies have shown meniscal tears on in the knee; (2) it does not require the use of ionizing radi­ MRI scans ofas ymptomatic patients. Boden et a1 . 30 studied ation ; and (3) it is noninvasive. Disadvantages of MRI 74 asymptomatic patients. Sixty -three were under age 45, include (1) a relatively high cost; (2) the amount of time and eight of these (13%) were fo und to have meniscal tears. 584 CHAPTER 17 • Injuries to the Meniscus and Articular Cartilage

Figure 17-6 Categorization of menisci accord ing to magnetic re sonance imaging (MRI) results. A, Grade 0: Normal meniscu s. B, Grade I: Mild intrameniscal signaL C, Grade II: Intrameniscal signal. D, Grade III: Complex tear of the medial me niscus.

Eleven patients were over age 45, and four (36%) had posi­ meniscus and the meniscocapsular junction. It also allows 1 tive findings on MRl.30 LaPrade et al.3 found MRl scans visualization of the lateral meniscus at the popliteal hiatus to be positive in 5.6% of knees in asymptomatic patients and probing to determine whether hypermobility is present. 18 to 39 years of age who had normal physical examination J findings.3 Classification of Meniscal Tears

Arthroscopy Meruscal tears can be classified as oblique, vertical longitu­ Arthroscopy is the gold standard for the diagnosis of menis­ dinal, radial (or transverse), horizontal cleavage, or com­ cal tears. Arthroscopic examination allows direct visualiza­ plex (Figure 17-7). Several authors have evaluated the tion of the tibial and femoral articular surfaces of the incidence of these tear patterns. Metcalf et al. 32 determined Injuries to the Meniscus and Articular Cartilage • CHAPTER 17 585

Figure 17-7 Types of meniscal tears.

Oblique Transverse tear Vertical tear Flap tear (Parrot-beak) tear

Peripheral tear Vertical longitudinal Discoid meniscus; Complex tear (Bucket-handle) tear degeneration and tear

that 81% of tears were oblique or vertical longitudinal. meniscus in ACL-deficient knees. Bucket handle tears occur As patients get older, the incidence of complex tears more often in the medial meniscus, probably because of its increases. Most meniscal pathology is found in the poste­ more rigid attachments and susceptibility to shear forces. 33 rior horns. The study by Binfield et al. evaluated knees that, on aver­ Oblique tears are most commonly found at the junction age, had suffered an ACL injury 23.3 months earlier. This of the posterior and middle thirds of the meniscus. These interval is sufficient from the time or original injury for tears are commonly calJed "flap" or "parrot beak" tears knee instability to generate medial meniscal tears. Vertical (Figure 17-8). longitudinal tears occur most often in the posterior horn Vertical longitudinal tears, also called "bucket handle" of the meniscus and can involve the entire meniscus tears, occur most often in young patients. These tears are (Figure 17-9). 33 commonly associated with ACL tears. Binfield et al. Bucket handle tears are unstable and, if large enough, showed a 9% incidence of bucket handle tears of the medial can dislocate into the intracondylar region, causing a

Figure 17-8 Arthroscopic vie w of an oblique (parrot beak) tear of the me niscu s. Symptoms likely result from the flap getting caught in the joint and pulling on the meniscocapsular junction. This also could lead to propagation of the tear. 586 CHAPTER 17 • Injuries to the Meniscus and Articular Cartilage

Figure 17-9 Figure 17-11 Arthroscopic view of a bucket handle tear of the meniscus. Arthroscopic view of a radial meniscal tear.

Figure 17-10 Figure 17-12 Arthro scopic view of an incomplete vertical longitudinal tear of the Arthroscopic view of a horizontal cleavage tear. meniscus. mechanical block to extension (locking). Incomplete verti­ Horizontal cleavage tears start near the inner margin of cal longitudinal tears can occur on the femoral or tibial sur­ the meniscus and extend toward the capsule . Shear forces face of the meniscus (Figure 17- 10). within the meniscus during load transmission likely cause The clinical significance of incomplete bucket handle a separation of the horizontally oriented collagen flber tears is questionable. Fitzgibbons and Shelbourne34 found bundles. The incidence of horizontal cleavage tears that incomplete vertical longitudinal tears of the lateral increases with age (Figure 17-12 ). Parameniscal cysts are meniscus that had been found at the time of ACL recon­ most often associated with these tears . These cysts often struction remained asymptomatic after ACL reconstruction form when horizontal cleavage tears reach the paramenis­ if they were stable at the time of surgery. cal region .36 Radial, or transverse, tears of the meniscus usually are Complex tears of the meniscus, often called degenerative located at the junction of the posterior and middle thirds tears) occur in multiple planes (Figure 17-13). Most of the meniscus. Complete radial tears disrupt the circum­ patients with complex tears are over 40 years of age. ferential fibers of the meniscus (Figure 17-11). Jones These tears most often occur at the posterior horn of the et a1.35 showed that a complete radial tear completely dis­ medial or lateral meniscus and are commonly associated rupts the function of the meniscus, leading to significantly with degenerative changes in the articular cartilage of the increased joint contact stresses. knee. Injuries to the Meniscus and Articular Cartilage • CHAPTER 17 587

Surgical Intervention

Surgeons should develop a standard approach to knee arthros­ copy. A diagnostic arthroscopy of the entire knee should be performed as the initial portion of all knee arthroscopies. This diagnostic arthroscopy can be performed in a n umber of ways, but each surgeon should choose one routine and stick to it to avoid missing pathology. The final decision as to whether the meniscal tear should be repaired or excised should be made after the diagnostic arthroscopy. Most meniscal tears are not amenable to repair. These tears usually require partial menis­ cectomy to relieve the patient's pain and mechanical symp­ toms. When a partial meniscectomy is performed, as much of the functioning meniscus as possible is left, to maximize the function of the remaining meniscus and minimize the effect on joint biomechanics. Figure 17-13 Indications for meniscal repair can be divided into patient Arthroscopic vie w of a complex meniscal tear. Note the shredding of factors and meniscal factors. Patient factors include the the meniscus. chronicity of symptoms, the patient's ability to tolerate the longer rehabilitation required after repair, and the risk of fail­ ure of the repair. The patient's age also should be factored Treatment of Meniscal Tears into the equation, because younger patients are likely to have a greater chance of progression to arthritis after meniscect­ Indications for Surgical Treatment omy. Meniscal factors that are favorable for repair include a Not all meniscal tears require surgical intervention. Before complete vertical tear longer than 10 mm, a tear within the deciding on surgery for meniscal pathology, the clinician peripheral 10% to 30% or within 3 to 4 mm of the menisco­ must exclude other causes of knee pain, such as degenerative capsular junction (red-red zone), an unstable tear that can be chondral changes. For surgery to be considered, symptoms displaced by probing, a tear without secondary degeneration of meniscal injury should limit activities of daily living, work, or deformity, and tears in stable knees or associated with or sports. Some meniscal tears heal spontaneously; therefore concomitant ligamentous reconstruction.30 If both patient a trial of conservative management, with activity modifica­ and meniscal factors indicate that the tear is amenable to sur­ tion and rehabilitation, should be attempted before surgical gical repair, then repair should be performed. 37 intervention . Henning et a1. showed that some tears heal As previously mentioned, some meniscal tears heal spon­ spontaneously or remain asymptomatic, including short ver­ taneously or remain asymptomatic . If one of these tears is tical tears (less than 10 mm), stable vertical longitudinal seen at the time of diagnostic arthroscopy and the knee is tears, partial thickness tears (less than 50% of meniscal stable or is undergoing ACL reconstruction, the meniscus depth ) on the tibial or femoral surfaces, and small radial tears can be left alone, or trephination (surgical excision of a cir­ (less than 3 mm ). cular piece of tissue ) and rasping can be performed without 37 38 surgical stabilization. Weiss et al . reviewed 52 patients with stable vertical longitudinal meniscal tears (less than Indications for Meniscal Surgery 3 mm of displacement with probing) and performed repeat

• Symptoms limit activities of daily living, work, or sports arthroscopy. Complete healing was noted in 65% of these • Conservative treatment has not improved symptoms patients. Only six patients required further treatment, and 38 four of those had suffered a new traumatic event.

If the meniscal injury is associated with an ACL injury, Meniscal Resection the timing of surgery usually is dictated by the acute reha­ Total meniscectomy used to be a very common procedure. bilitation after the ACL injury. Factors such as swelling Fairbank39 first described the damaging effects of total and range of motion dictate the timing of ACL reconstruc­ meniscectomy in 1948. As long-term results became avail­ tion. Meniscal pathology usually can be addressed at the able, the progression to osteoarthritis was noted; conse­ time of ACL reconstruction. If a displaced bucket handle quently, total meniscectomy has become a very uncommon meniscal tear is limiting recovery of extension after an procedure.40,41 With arthroscopic techniques, partial menis­ ACL injury, the meniscal tear should be dealt with on an cectomy has become feasible (Figure 17-14). urgent basis to allow the patient to regain full extension When meniscal repair is not indicated, surgeons now before proceeding with ACL reconstruction. perform a partial meniscectomy. Metcalf et al.32 established 588 CHAPTER 17 • Injuries to the Meniscus and Articular Cartilage

of effusion,regaining full strength, and a progressive return to preinjury or preoperative activity. These goals can be achieved eimer in a formal rehabilitation setting or wim home treatment. Icing and elevation can help minimize pain and effusion in tile knee. ROM exercises can be started immediately after surgery. Patients may bear weight as tolerated. Quadriceps strengthening exercises can begin immediately after surgery. Patients should avoid twisting and repetitive inlpact activities for 4 to 6 weeks after surgery.

Meniscal Cysts As mentioned, meniscal cysts occur most often with hori­ zontal cleavage tears. These cysts usually can be decom­ pressed at me time of partial meniscectomy from within 32 Figure 17-14 the joint. Metcalf et al . showed that meniscal cysts rarely Artshroscopic view of a partial meniscectomy. recur if the meniscal pamology is dealt with appropriately. The results of arthroscopic decompression of cysts range guidelines for meniscal resection. All mobile fragments of from 90% to 100% withom recurrence. If the cyst is not the meniscus that can be pulled past the inner margin of easily identified from within the joint, a needle can be the meniscus into the center of the joint should be passed percutaneously through the cyst into tile joint and resected. The remaining meniscal rim should be smoothed the location of me cyst identified arthroscopically. The cyst men can usually be decompressed by probing or shaving to remove any sudden changes in contour that may lead to 45 46 further tearing. A perfectly smootll rim is not necessary. from wimin me joint. , If the cyst cannot be decom­ A probe should be used to gain information about me sta­ pressed arthroscopically, an open cyst excision should be bility or mobility of tile remaining meniscus. The menisco­ performed. capsular junction and tile meniscal rim should be retained, if at all possible, to preserve tile load transmission proper­ Meniscal Repair ties of the meniscus. Motorized and manual instruments Some meniscal tears can heal without fixation. As previ­ should be used. Manual instruments are more accurate, ously mentioned, meniscal tears that can be left to heal and motorized shavers can remove loose debris and smoom Witllout fixation include vertical longitlldinal tears less than frayed edges. 10 mm long, incomplete tears, and stable tears that move 34 less man 3 mm wim probing. In such cases, me surgeon Partial Meniscectomy can attempt to enhance tile healing response with abrasion Studies on the short-term outcome of partial meniscectomy of the synovial surfaces and meniscal trephination 47 Syno­ have shown 80% to 90% good results at less man 2-year vial abrasion causes a vascular pannus that migrates into follow -up.42 A number of long-term follow-up studies have the tear and helps produce a healing response. Meniscal shown progression of artllritis radiographically after partial trephination is a variation of creating vascular access chan­ 4 meniscectomy. Fauno and Nielsen 3 found tllat Witll 8 years nels. Horizontally oriented holes are made using a spinal of follow-up, radiographic changes occurred in 53% of needle tllrough me peripheral vascularized region of the 48 knees that had undergone partial meniscectomy, compared meniscus. Fox et al. showed a 90% success rate in healing 44 to 27% of untreated, contralateral knees. Schimmer et al . incomplete tears wim trephination . found good or excellent results in 91. 7% of partial menis­ When a meniscal tear is found to be amenable to repair cectomies at 4 years, but this dropped to 78. 1% at 12 years. and tile patient understands the risks of meniscal repair Articular cartilage damage associated with tile meniscal tear and tile rehabilitation required (described later in this chap­ had the greatest impact on tile long-term outcome. Sixty­ ter ), a series of steps must taken to maximize tile chances of two percent of patients who had articular cartilage damage success of tile repair. First, the meniscal bed must be at the time of me index operation had a good or excellent prepared. Loose edges of the tear should be debrided. result at fmal follow-up. In patients Witll no articular carti­ The torn meniscal edges should be abraded with a rasp or 44 lage damage, 94. 8% had good or excellent results. shaver. Rasping of the synovial fringe is also helpful in cre­ Postoperative Rehabilitation. Rehabilitation after ating a synovial pannus that can creep into the tear and aid partial meniscectomy usually is uneventful. Postoperatively, the healing response. Tears that extend into the avascular rehabilitation focuses on pain control, joint mobilization zone have a lower healing rate. Some think that this can and range of motion (ROM ), gait training, minimization be improved somewhat with trephination. Injuries to the Meniscus and Articular Cartilage • CHAPTER 17 589

Open Repair Techniques. Open meniscal repair was saphenous nerve . The needles can be visualized as they pass 49 first repor ted by Annandale in 1885. Meniscal repair tllrough the ca psule . did not become widely used until it was popularized by On the lateral side of the knee, tlle peroneal nerve is De Haven50 and Wirth.51 Open meniscal repair currently most at risk. The popliteal artery and tibial nerve are at risk is most useful with multiple -ligament injuries in which the as the sutures move more posteriorly. The lateral capsule collateral ligament injuries may require open repair or tibial should be exposed before needles are inser ted fr om within plateau fr actures require open reduction and internal fixa­ tlle knee joint. An incision is made on the lateral side of tion . With open repair, the meniscus can be sutured the knee just posterior to the fibular collateral ligament. directly. The success rate fo r open meniscal repair is high Again , dissection is performed with the knee in 90° flexion . in multiple-ligament injuries, likely because of tlle periph­ The peroneal nerve is protected by finding tlle interval eral nature of the tears and the acuteness of the injury between the biceps femoris and the iliotibial band and and the ensuing hemarthrosis. Rockborn and Gillquist52 retracting the biceps and peroneal nerve posteriorly. The reported a 71% success rate in a 13-year fo llow-up of lateral gastrocnemius muscle is found and its fa scia is pa tien ts with open meniscal repairs. Some surgeons still divided in the direction of its fibers. Fibers of the lateral advocate open meniscal repair, suggesting tlut meniscal head of the gastrocnemius are dissected off of the posterior pre paration and suturing are more readily achieved with capsule. A retractor then can be placed posteriorly in tlle an open approach and that the incisions do not need to knee to protect the neurovascular structures. Once this dis­ be much larger than with inside -out arthroscopic repairs . section has been per formed, needles can be safely passed Arthroscopic Repair. Ar throscopy allows evaluation fr om inside the knee and retrieved as they exit the capsule , and treatment of meniscal tears that are not possible with witho ut risk of neurovascular injury. open te chniques . Three basic suturing te chniques have After tlle appropriate exposure and neurovascular pro­ been used wIth ar throscopic procedures : the inside-out te ction have been obtained, attention can be returned te chnique, the outside-in te chnique, and the all-inside to the meniscal pathology. The menisca I bed is prepared technique . Ar th roscopic repairs also can be performed (Figure 17-15), and sutures tllen can be passed through using bioabsorbable implants and suture an chors . the meniscus, exiting tlle knee joint capsule . The sutures Inside-Out Technique. The inside -out te chnique was should be passed in a vertical mattress pattern fo r maximum first popularized by Henning et al . 37 in tlle early 1980s. strength ; ideally, tlley should be placed at 2 to 3 mm This te ch nique uses double-armed sutures witll long intervals (Figure 17-16 ).54 needles, which are positioned through arthroscopically Outside-In Technique. The outside-in te chnique was directed cannulas . Skin incisions are then made between developed as an attempt to avoid the neurovascular compli­ the two needles . Soft tissues are dissected down to the cap­ cations that can occur with the inside-out te chnique . The sule, with care taken that no neurovascular structures are outside-in te chnique uses a spinal needle passed percutane­ trapped between the sutures, and tlle sutures are then tied, ously through tlle subcutaneous tissue , through the menis­ reducing the meniscus . A significant advantage of this te ch­ cal tear, into the knee joint. A suture tllen is passed in to tlle nique is that it allows accurate suture placement in the join t through the needle and brought out through the meniscus . The main disadvantage of this te chnique is the anterior por tal . A knot is tied in the fr ee end of the suture , risk to neurovascular structures and the need for incisions between tlle sutures. When this te chnique is per formed on the medial side of the knee, branches of the saphenous nerve are most com­ monly injured . 53 Injuries to the saphenous nerve can cause localized numbness or a pain ful neuroma . The standard medial in cision is a vertical incision approximately 3 cm (1.2 inches ) long that star ts just above the joint line and runs distally. The incision is made witll the knee in 90° flex­ ion . The in frapa tellar branch of the saphenous nerve runs approximately 1 cm (0.5 inch ) proximal to the joint line . The saphenous nerve usually lies below tlle subcutaneous fat on tlle deep fascia covering the sartorius muscle . Ke eping the knee in 90° flexion allows the sartorius and saphenous nerve to fall posteriorly. Once the subcutaneous tissue has been bluntly dissected down to the sartorius fa s­ cia , the fascia is opened in the direction of its fibers and a plane is dissected down to tlle knee joint capsule. A retrac­ Figure 17-15 tor can then be placed in tllis plane, protecting the Arthroscopic view of a bleeding edge in the red zone of the menisclls. 590 CHAPTER 17 • Injuries to the Meniscus and Articular Cartilage

Figure 17-16 Arthroscopic view of vertical mattress sutures in place, ready to be tightened and tied .

and the su ture is pulled back into the joint, reducing the meniscal tear. Ad jacent sutures are tied to each other out­ side the capsule. 55 A small incision is made between the two sutures, the soft tissues are cleared between the sutures Figure 17-17 Meniscal repair devic es. A, SDsorb Staple, Mitek Meniscal Repair down to the capsule (with care ta ken that no neurovascular System, Biomet Staple. B, Meniscal repair devices (left to t'ight): structures are caught between the sutures), and the sutures Miteck Meniscal Repair System, Clearfix Screw, Arthrex Dart, Bionx are then tied as in the inside-out technique. Meniscus Arrow, Linvatec Biostinger, Smith & Nephew FasT-Fix, Modifications ofthe original outside-in technique have and 2-0 Ethibond suture. (From Farng E, Sherman 0: Mcniscal emerged. In one such modification, a needle is placed per­ repair devices: a clinical and biomcchanical literature review, Arthroscopy 20[3]:273-286, 2004.) cutaneously, as previously described, to pass the first suture into the knee, fo llowed by a parallel needle with a wire suture retrieval loop. The first suture is passed through Barber et al S6 reported on the BioStinger (Linvatec, the loop and pulled out of the knee joint through the sec­ Largo, FL). Their sUldy showed a 91% success rate with ond needle, leaving one intact suture that can be tied out­ the device, compared to a 100% success rate fo r the vertical side the capsule. This essentially leaves the patient with mattress inside -ollt suturing technique. Haas et al.57 the same final configuration of su tures as an inside-out reported a 91% success rate fo r the FasT-Fix (Smith & technique. Nephew, Memphis, TN ) when the meniscal tear is associated The outside-in technique is most useful fo r tears in the with an ACL reconstruction and an 80% success rate fo r anterior or middle third of the meruscus. To perfor m this isolated meniscal repffirs. The Meniscal Arrow (Linvatec ) technique fo r posterior tears, the surgeon must use an open has similar success rates. Meniscal repffir devices raise several approach to allow safe passage of the needles into the knee concerns. Most have been shown to be biomechanically joint. inferior to vertical mattress sutures,58 and all of these devices All-Inside Technique. The all-inside suture repffir is can be associated with fe moral chondral damage. Gliatis useful fo r tears ofthe posterior portion ofthe medial or lat­ et aI.59 reported on chondral injury caused by migration of eral meniscus. A posteromedial or posterolateral working a Mitek RapidLoc meniscal repair implant; this report was portal and a 700 arthroscope are required. Visualization is associated with a sllccessful meniscal repair. obtained with the 700 scope, and a curved, cannulated Results of Meniscal Repair. Meniscal repairs have su ture passing device is used to pass the sutures through been evaluated using second look arthroscopy, double con­ the posterior portal. Arthroscopic knot tying techniques trast arthrography, MRI, and clinical examination with the are used to tie the sutures within the knee joint. absence of sy mpto ms referable to meniscal pathology. Meniscal Repair Devices. A number of devices have To evaluate the success rates fo r meniscal repair fo und in been developed to allow meniscal repair without the risk the literature, readers must ta ke into account the de finition of ne urovascular injury or the need fo r secondary incisions of successful repair. Success rates are higher fo r patients (Figu re 17-17). who undergo ACL reconstruction at the time of meniscal Injuries to the Meniscus and Articular Cartilage • CHAPTER 17 591 repair than fo r patients who have isolated meniscal repairs. 38% were partially healed, and 36% fa iled. Seventy-three When meniscal repair success rates are evaluated, patients percent of the patients with unhealed menisci had symp­ who had con comitant ACL reconstruction must be toms referable to the tibiofemoral joint. grouped separately and the length of fo llow-up must be critically evaluated. Studjes have been published on the Indicators of Successful Meniscal Repairs short -term results of meruscal repair, but success rates decline if patients are fo llowed fo r longer than 2 years. • Repairs are done at the same time as ACL reconstruction 60 Albrecht -Olsen et al reviewed 27 patients at a median • Lateral meniscal repairs are more successful than medial 3-year tallow-up, using a clinical examination to determine meniscal repairs success. They showed a 63% success rate, and all knees were • Tear is in the peripheral one third of the meniscus stable. Buseck and Noyes61 reviewed 66 repairs associated • A functioning meniscus is present with ACL reconstruction. All patients underwent second look arthroscopy. Eighty percent were completely healed, 14% were partially healed, and 6% fa iled. Ninety -eight per­ Postoperative Rehabilitation. Rehabilitation after cent of tears in the outer one third healed. Cannon and meniscal repair depends on whether ACL reconstruction 62 Vittori looked at stable knees and knees that underwent was per formed at the same time. Although many protocols ACL reconstruction at the time of meruscal repair. Of the exjst, the principles of rehabibtation include an irutial period stable knees, 50% healed, wh ereas 90% of the knees that of non-weight-bearing and limitation of flexion. Standard underwent concomitant ACL reconstruction healed. Heal­ meniscal repair guidebnes are presented in Table 17-1. ing was con firmed with arthroscopy or an arthrogram. If ACL reconstruction is per formed concomitantly with 63 Ru bman et al evaluated 198 meniscal tears that the meniscal repair, more aggressive ROM exercises should extended into the avascular (white ) zone. Clinical examina­ be performed. Flexion should be limited to 90° fo r tlle first 64 tion showed that 80% of these patients had no symptoms 4 to 6 weeks. Arnoczky et al. showed that the meniscus is referable to meniscal pathology. Second look arthroscopy subject only to small amounts of motion and stress between was per formed in the 20% who had symptoms. Of the 15° and 60° flexion. After 6 weeks, more aggressive closed 39 knees that underwent second look arthroscopy , only bnetic chain activities can be started. Return to pivoting two tears were healed. Thirteen tears were partially healed, sports should not be allowed before 6 months. and 24 had fa jled . In the entire group, 91 repairs were eval­ Complications of Meniscal Repair. The most com­ uated arthroscopically. Of these menisci, 25% were healed, mon complication of meniscal repair is fa ilure of healing

Table 17-1 Rehabilitation Protocol After Meniscal Repair

We eks 1-2 Weeks 3-4 Weeks 5-6 We eks 7-8 We eks 9-16 We eks 17-20 We eks 21-24

Brace Immobilized Immobilized No brace No brace No brace No brace No brace

We ight NWB PWE WE as WE as WE as WE as WE as bearing tolerated tolerated tolerated tolerated tolerated

R.1nge of 0°_900 00_900 00- 1200 Full ROM Full ROM Full ROM Full ROM mot io n

Exercises Iso metric Isometr ic Begin closed Closed chain Closed chain Run ning, Cutting Quad Quad chain exerCises exerCises straight Exer cises Exercises exer cises Hamstrings Hamstrings • Quadsets • Quad sets Stationary Stationary • SLR • SLR bike bike Stair climber Manual Patellar Patellar and Patellar and Patellar and therapy mo bilization joint joint joint mo bilization mobilization mobilization Passive ROM Passive ROM to 900 to 1200

NWB, Non- weight-bearing; PWB, partial weight bearing; WB, weight bearing; ROM, range of motion. 592 CHAPTER 17 • Injuries to the Meniscus and Articular Cartilage and the need for subsequent partial meniscectomy. Other nearly complete remodeling at 6 and 12 months. Debeer 3 complications specifically associated with meniscal repair et al.7 showed tlut 95% of the dem.. ,),rib onucleic acid include injury to the saphenous nerve or vein, injury to (DNA) in a human transplanted meniscus was identical to the peroneal or tibial nerve, and injury to the popliteal artery that of the recipient at 1 year, which indicated that the host or vein. Loss of motion after repair also can be associated bad repopulated the meniscal cells. with meniscal repairs.53,65,66 Deep vein thrombosis, pain, Indications for Meniscal Transplantation. The infection, and hemarthrosis can occur but are not seen at a ideal patient for meniscal transplantation is one who previ­ higher rate than with partial meniscectomy. Shelbourne ously bas undergone complete or near complete meniscect­ and Johnson67 reported a 25% incidence of stiffness when omy and has joint line pain, early chondral damage, a stable ACL reconstruction is performed at the same time as repair knee, and normal lower limb alignment. Meniscal trans­ of a locked bucket handle meniscal tear. Meniscal repair per­ plantation can be considered at the same time as ACL formed at the same time as ACL reconstruction does appear reconstruction in an ACL-deficient knee. If axial malalign­ to be a risk factor for postoperative stiffuess; however, ment is present, tibial or femoral osteotomy should be meniscal healing rates are higher when meniscal repair and considered to correct it. Meniscal transplantation is contra­ ACL reconstruction are performed at the same time. indicated in patients with advanced chondral changes.74 At tl1is point, no evidence supports meniscal transplanta­ tion in asymptomatic patients who have undergone com­ Complications of Meniscal Surgery plete or near complete meniscectomy. As longer term

• Nerve injury (saphenous, peroneal, tibial) results become available, the indications may expand to • Vascular injury (saphenous, popliteal) cover asymptomatic young patients with complete • Loss of range of motion (stiffness) meniscectomies. • Deep vein thrombosis • Pain • Infection Indications for Meniscal Transplantation • Hemarthrosis • Previous complete or near complete meniscectomy • Joint line pain • Early chondral damage Meniscal Transplantation • Stable knee • Transplantation of the meniscus was first described by Mila­ Normal lower limb alignment chowski et al.68 in 1989. The experience with human meniscal transplantation was preceded by clinical studies in animals and cadavers. Cadaveric models have shown Graft Sizing. Graft SIZIng is extremely important. decreased contact pressures and increased contact surface To obtain the beneficial biomechanical effects of meniscal areas after meniscal transplantation. Both the anterior and transplantation, tl1e transplanted meniscus should vary less posterior horns of the meniscus must be securely attached than 5% from the original meniscus. Various studies have in their anatomical positions to gain these biomechanical used computed tomography (CT) scans, MRI, and plain advantages. When both anterior and posterior attachments radiography for meniscal allograft sizing. A study by Shaffer are released, the decrease in contact stresses is completely et al.74 showed that MRI was accurate to within 5 mm of lost. If one attachment site is lost, some biomechanical width and length measurements in 84% of cases, compared benefit is obtained, but it is significantly reduced.69 to 79% of cases measured with plain radiographs. Most tis­ Arnoczky et al?O transplanted cryopreserved medial sue banks use plain radiographs for allograft sizing.75 meniscal allografts in 14 dogs. These menisci healed to tl1e Surgical Technique. The insertion of meniscal allo­ capsule by fibrovascular scar. At 3 months they maintained grafts has been described using an open technique with col­ a normal gross appearance. Histological studies showed that lateral ligan1ent detachment, an open technique without the transplanted menisci maintained a normal cellular distri­ collateral ligament detachment, and an arthroscopically bution. Jackson et al 71 used a goat model to compare auto­ assisted technique. The results of meniscal transplantation graft to fresh allograft and cryopreserved allograft. At 6 seem to depend on patient selection, graft sizing, and months, the implanted menisci appeared very similar histo­ secure graft fixation more than surgical technique. As logically to the controls. A slight decrease was seen in the cel­ described previously, to increase the contact surface area lularity in tl1e central portions of tl1e menisci. Peripheral and reduce contact stresses, the surgeon must securely fix vascularity was almost normal. The water content of the tl1e anterior and posterior horns. Soft tissue fixation, fixa­ meniscus was increased and tl1e proteoglycan content was tion with bone plugs, and fixation with a bony bridge decreased compared to controls. In another study, Fabriciani inserted into a trough in the tibial plateau have been et al. 72 demonstrated little difference between cryopreserved described as techniques for secure anterior and posterior and deep-frozen meniscal transplants. Their study showed horn fixation (Figure 17-18). Injuries to the Meniscus and Articular Cartilage • CHAPTER 17 593

Articular Cartilage lesions

The treaU11ent of full thickness articular cartilage lesions in tl1e knee is a field tl1at is quickly evolving. Untreated articular cartilage lesions have little or no potential to heal . However, some studies show tl1at a large number of patients will have isolated chondral defects and remain asymptomatic without treatment. Messner and Maletiul8 reviewed a series of 28 patients with isolated chondral lesions; 22 had either good or excellent clinical results witl10ut treatment 14 years after diagnosis. Most of mese 22 patients had abnormal radiographic findings suggesting progressive degenerative changes. Altl10ugh mese data suggest tl1at isolated chondral defects may predispose patients to the development of fur­ mer degenerative changes in the knee, long-term prospective data have not been obtained that link isolated chondral defects to progressive degenerative arthritis of tl1e knee that compromises a patient's level of function. Figure 17-18 Meniscal allograft with bony attachments. (From InsaJl IN, Scott WN: Stt1lJcry of the knee, cd 3, p 552, New York, 2001, Churchill History Livingstone . )

The clinical presentation of a full thickness chondral defect Results. The results of meniscal transplantation vary sig­ can vary. Some patients complain of loose body-type symp­ nificantly witl1 patient selection. Noyel6 reported on a series toms witl1 locking, catching, and clicking. Other patients of 96 meniscal allografts. MRI and ariliroscopic evaluations complain of crepitus with intermittent mechanical symp­ were used in mis study to determine graft success rates. toms, and a third group presents with pain as the only Twenty-two percent healed, 34% partially healed, and 44% symptom. The clinician should obtain a careful history to failed . When tl1ese results were broken down, normal knees determine whetl1er the symptoms are indeed coming from had a 70% healing rate, witl1 the otl1er 30% partially healed, within me knee joint and, if so, whether they are coming whereas knees witl1 severe arthrosis had a 50% failure rate from me medial, lateral, or patellofemoral compartment. and 50% partial healing. Cameron and Salla77 reported on 67 meniscal allografts with 87% good or excellent results using Physical Examination a modifiedLyshoLm rating score. These aumors performed 34 tibial osteotomies and suggested in tl1eir conclusions mat limb A thorough physical examination should be performed for alignment was important to tl1eir success rates. Otl1er studies all patients suspected of having chondral defects of tl1e knee. have shown tl1at meniscal transplantation performed with The clinician should begin the examination by watching the appropriately sized grafts witll secure fixation in patients with patient stand and walk, noting limb lengtl1 and alignment normal alignment and only early chondral changes can pre­ and observing any gait abnormalities, such as valgus or varus dictably reduce pain and increase knee function?5 thrust during me stance phase of gait. A low back examina­ Postoperative Rehabilitation. Rehabilitation proto­ tion also should be done, and a complete distal neurological cols vary among surgeons who perform meniscal allograft and vascular examination should be performed. Examination transplantation. In general, rehabilitation protocols are similar of tl1e hip is critical in any patient presenting witl1 knee to those for meniscal repair. Patients are kept non-weight­ symptoms. A systematic examination of botl1 knees should bearing or partial weight bearing for me first 4 to 6 weeks. be performed. Thigh circumference and range of motion Range of motion is allowed but is limited to 90° flexion for should be compared between tl1e two sides. Pain experi­ the first 4 to 6 weeks. Muscle strengthening is progressed enced by me patient during range of motion should be gradually witl1 closed chain quadriceps and hamstring exer­ noted. The knee should be examined for an effusion. cises. Pivoting activities are restricted for me first 6 montl1s. Knee stability should be examined, including testing of the anterior and posterior cruciate ligaments, the tibial Summary (medial) collateral ligament, the fibular (lateral) collateral The U'eatment of meniscal pathology is a continually ligament, and the posterolateral (popliteus) corner. The changing field. The art and science of meniscal repairs have knee should be palpated for any local tenderness. The advanced tremendously. The future holds potential for extensor mechanism should be examined for continuity, meniscal allograft transplantation and for me development and the alignment of tl1e extensor mechanism (Q angle) of meniscal replacements. should be measured. The mechanics of the patellofemoral 594 CHAPTER 17 • Injuries to the Meniscus and Articular Cartilage ar ticulation should be examined, and the clinician should observe for a J sign (i.e., deviation of the patella cephali­ cally and la terally in the pattern of an upside-down J), lat­ eral tilt of the patella, lateral retinacular tightness, and patellofemoral crepitation .

Diagnostic Imaging

Diagnostic imaging should begin with plain radiographic fil ms. A standing PA flexion view should be included in th e standard kn ee series. A tangential view of the patellofe­ moral joint (e.g., Merchant view) should also be included. These plain radiographic films can show joint space narrow­ ing, osteochondral defects, and patellofemoral tilt or sub­ luxation . However, isolated chondral defects often cannot be seen on plain radiographic films. The imaging study of choice for chondral defects is MRI because of its excellent sensitivity and specificity for this type 79 Figure 17-20 of lesion. Bredella et al. reported on 130 patients under­ T I-weighted MR1 scan of a trochlear chondral defect (circled). going kn ee arthroscopy for suspected internal derange­ ment. Of 86 arthroscopically proven abnormalities, 81 were detected with MRI. MRI done with a T 2-weighted, fast in flammation all can minimize sy mptoms. Or thotics, brac­ spin-echo sequence with fat saturation had a sensitivity ing, and gait training can minimize th e stresses on the of 94% and a specificity of 99% compared to arthroscopy affected region of the joint. Weight loss in overweight (Figures 17-19 and 17-20). patients can dramatically improve sy mptoms by reducing patellofemoral and tibiofemoral contac t stresses.

Nonoperative Management Surgical Management The goal of nonoperative management of chondral lesions is to mini mize symptoms and allow maximum activity. The ultimate goal of surgical tr eatment is restoration of th e Maintenance of range of motion, muscle strengthening, microarchitecture of th e articular cartilage, which allows and a variety of therapeutic modalities to reduce pain and complete restoration of th e biomechanical and physiologi­ cal function of the knee. A number of techniques for car ti­ lage repair and regeneration have been developed . The following sections present a detailed look at each of th ese modalities and review th e basic science, surgical techniques, and rehabilitation principles and results.

Abrasion Arthroplasty The idea of doing something to eburnated bone to cause a reparative tissue response was first proposed by Pridie80 in 1959. He recommended joint debridement, removal of osteophytes, retention of th e patella, shaving of fissured articular cartilage, and drill ing of eburnated bone. He described fibrous, reparative-type tissue filling and covering 0.5 cm (0.25 inch) cortical drill holes through th e femoral condyle. Most of his poor results involved patients in whom he also performed a patellectomy. Akeson et al.81 attempted to confirm Pridie's findings in laboratory ani­ mals. They removed th e articular cartilage and subchondral bone of dog femoral heads. At I-year follow-up, th ey con­ cluded that excessive loading destroy ed th e initial reparative

Figure 17-19 tissue. These results also showed that th e proteoglycan con­ T rweighted MRl scan of a chondral defect (outlined by lVhite dotted centrations in th e reparative tissue were less than half 82 line) of the poste rior condyle. that of nor mal ar ticular car tilage . Mitchell and Shepard Injuries to the Meniscus and Articular Cartilage • CHAPTER 17 595 studied rabbit knee joints. They found that after multiple debridement of unstable chondral flaps. Contraindications small holes were drilled into the subchondral bone, repara­ to microfracture include axial malalignment , partial thickness tive tissue was stimulated to cover large areas of articular sur­ chondral defects, and a patient who is unable or unwilling to faces. The reparative tissue grew out from the drill holes and comply with a strict postoperative reh abilitation protocol, then spread over the exposed bone. This tissue began to including minimal weight bearing . Joint space narrowing, fibrillate and break down within 1 year82 These two studies chronic lesions, and inability to use a CPM machine may were the first to demonstrate that a fibrocartilaginous repair affect the outcome but are not su-ict con u-aindications. tissue could be stimulated to form on larg e areas of articular Surgical Technique. Microfracture can be performed surface. However, these studies also showed that this repara­ arthroscopically with a combination of shavers, curets , and tive tissue did not have the proteoglycan concentration of picks. The techniqu e has been described by Steadman articular cartil ag e and that it started to break down quickly et al .86 Three portals ar e made, allowing use of an inflow with excessive loading. canula, the arthroscope, and the working instruments. A diag­ Ab rasion arthroplasty using motorized instrumentation nostic arthroscopy is performed, and the full thickness chon­ 83 was introduced by Johnson in 1981. Whether the ab ra­ dral defect is identified. Any other work that needs to be sion should be int racortical or cancellous bone should be performed in the knee is completed before the microf racture 84 exposed is the subject of debate. Hjertquist and Lemperg procedure is begun. The chondral defect is then inspected , reported that cartilage tissue of mature appearance forms and all cartilage remnants are debrided (Figure 17-21 ). only if the debridement is superficial enough to maintain The articular cartilage surrounding the defect is a cortex . inspect ed and any loose, delaminated cartilage is removed. Surgical Technique. The procedure introduced by A perpendicular edge of healthy cartilage is obtain ed cir­ Johnson in 1981 is essentially an extension of that described cumferentially around the lesion . The calcified cartilage by Pridie. Along with debridement of the joint , a superficial layer is removed , which care taken not to debride through layer of subchondral bone (1 to 3 mm deep ) is removed to the subchondral plate. expose interosseous vessels. This theoretically results in a An arthroscopic awl with the appropri ate angle then is hemorrhagic exudate that fo rms a fibrin clot and allows used to create perforations in the subchond ral plate th at fibrous repair tissue to form over the area of exposed bone. are perpendicular to the surface. The awl allows the Rehabilitation. Regeneration of articular cartilag e surg eon to make holes (microfractures ) in the subchondral benefits from motion and from limiting the compressive bone with control and without any worry of heat necrosis force on the articular cartilage from weight bearing. Patient (Figure 17-22). Attention first is given to th e periphery of adherence to a program of motion with limited or no the lesion . Holes are made at 3 to 4 mm intervals around weight bearing is critical. To assist with this, the use of con­ the periphery and are approximately 3-4 mm deep. Once tinuous passive motion (C PM) often is considered. Weight the holes have been made around the periphery, the bearing often is rest ricted for up to 12 weeks, with daily remaining surface of the lesion is addressed . Holes should CPM, especially in the early postoperative period. Active be spaced as close together as possible without fracturing and passive range of motion are encouraged throughout the postoperative course until weight bearing and strength training can begin. Results. Eight knees were biopsied in Johnson 's original series.83 Of those eight biopsy specimens, only one showed any type II collagen typical of hyaline cartilage. All other biopsy specimens showed a combination of type I and type III collagen. Bert and Maschka85 reviewed a series of 59 patients who ullderwent ab rasion arthroplasty with a mini­ mum 5-year follow-up. Of the 59 patients, 15 had conver­ sion to tot al knee arthroplasty. Biopsies were performed on any rem aining fib ro us tissue. The fib ro us tissue was stained with safranin 0 to look for proteoglycan. The fibrous surface did not stain , indicating the lack of proteoglycan.

Microfracture Microfracture cm be performed on the patellar, tibial, or femoral articular surface. The general indication for micro­ fracture is a full thickness chondral defect in either a Figure 17-21 weight-bearing region or a region of contact between the Arthroscopic view of a chondral defect debrided to subchondral bone. femur and patella. Mic ro fracture can also be performed after The calcified cartilage layer has been removed . 596 CHAPTER 17 • Injuries to the Meniscus and Articular Cartilage

Clinical Point

A strict rehabilitation program is essential after microfracture treatment of chondral lesions of the knee.

Rehabilitation. Microfracture creates an environment in which pluri potent marrow cells can be stimulated to pro­ duce cartilage. However, the rehabilitation program ulti­ mately determines the success of the procedure. To design an appropriate rehabilitation program after microf racture, the clinician must think about the region that was affected and the kinematics of the knee. The ideal rehabilitation program encourages motion but limits weight bearing Figure 17-22 and shear stresses on the affected region. For these reasons, Arthroscopic view of a microfracture technique. Multiple pick holes are spaced 3-4 mm apart. the rehabilitation protocol is very different for weight-bear­ ing femoral condyle lesions than it is for patellar or troch­ lear lesions. Al l patients are put in a CPM machine postoperatively, and the patient is asked to use the CPM the subchondral bone between two holes (approximately 3 machine up to 10 hours per day 87 The rate of motion usu­ to 4 mm ). After the holes have been made, a shaver is ally is 1 cycle per minute. The CPM is started in a comfort­ used to re move all bony debris. The pump pressure then able range and increased as tolerated. Patients with femo ral is tu rned down to enable the surgeon to visualize fat dro­ condyle lesions are kept on toe touch weight bearing with plets and blood exiting fj·om all holes (Figure 17-23). crutches for 6 to 8 weeks. At 8 weeks, the patient can prog­ Any holes that do not show bleecling should be checked re ss to weight bearing as tolerated and can begin a more and possibly made deeper to allow bleeding. Afte r the sur­ vigo rous program of active motion. Strength training with geon has made sure that all holes have been made appropri­ weights or machines should be avoided for 16 weeks. ately, the knee is irrigated, instruments are removed, Return to sports that involve cutting, pivoting, and jump­ and the joint is evacuated of fluid. Incisions are closed, ing can be allowed at 4 to 6 months. and a sterile dressing is applied. The key to this procedure Patients who have patellar or trochlear lesions are is to establish a clot of pl uripotent marrow cells that can allowed to bear weight as tolerated immediately after sur­ then differentiate into stable cartilage under the right gery; however, the knee must be protected from loaded conditions. motion where the defect is engaged. At the time of arthrosco py, the knee joint can be taken through a range of motion to see specifically where the lesion is in contact with the opposing articular surface. In general, a patient with a trochlear or patellar microf racture can be put in a hinged knee brace with the brace set to move from full extension to 20° flexion. The knee should be taken out of the brace for CPM but should be braced at all other times to avoid shear forces across the lesion. The brace can be discontinued at 8 weeks. A re cent study by Gill et aL88 suggested that the period of restri cted weight bearing should be increased to 12 weeks. This study eval­ uated the healing process in cynomolgus macaques. His­ tological analysis was pe rformed 6 and 12 weeks after microfracture. At 6 weeks, limited chondral re pai r and ongoing resorption of subchondral bone were seen. By 12 weeks, the cartilage defects were completely filled and showed more mature cartilage and bone re pai r. Fur­ ther studies in humans are needed to dete rmine whether Figure 17-23 Arthroscopic view of a microfracture after reduction of pump pressure this ad ditional length of time makes a clinically significant shows bleeding fro m all holes. difference in the long-term outcome. Injuries to the Meniscus and Articular Cartilage • CHAPTER 17 597

89 Results. Steadman et al . looked at a series of 75 knees in 72 patients who underwent microfracture for full thic kness tra umatic chondral defects. Follow-up was 7 to 17 years . Their three inclusion criteria were (1 ) a traumatic full thickn ess chondral defect, (2) no meniscal or ligamen­ to us injury, and (3) patient age under 45 years . Significant improvements were fo und according to the Lysholm and Tegner knee rating scales . At 7 years after surgery, 80% of patients stated that they were better than before surgery. Some patients took up to 2 years to obtain maximum improvement. Kn utsen et a1 90 performed a randomized clinical trial comparing microfracture and autologous chon­ drocyte im plantation (ACI) for isolated chondral defects . Eighty patients were enrolled in the study. Microfracture was performed on 40 patients, and AC I was performed on the other 40. An independent observer performed the Figure 17-24 follow-up data collection at 12 and 24 months. Both View of a graft donor site on the periphery of the bteral fe moral gro ups showed improvement . According to the Short condyle. Form-36 (SF-36) outcome measurement tool, the micro­ fracture group had a significantly greater improvement . Biopsy specimens were obtained from 84% of patients at cartilage . The defect then is sized to determine the num­ 2 years. Hi�tological evaluation of repair tissues showed ber and sizes of grafts needed . If the defect can be no significant differences between the two groups. Interest­ accessed adequately arthroscopically, the procedure can ingly, no association was found between the histological be performed arthroscopically . A mini arthrotomy may be specimens and the clinical outcome, according to the required . The grafts can be obtained from either the Lysholm scale, tile SF-36, and a visual analog scale. medial or lateral peripheral margins of the femoral con­ dyles at the level of the patellofemoral joint. The appropri­ Mosaicp/asty ate-sized tube chisel is introduced perpendicular to the Autologous osteochondral grafting has shown great prom­ donor site, and the harvester is driven into the donor site. ise in that it is a means to transplant bone and hyaline car­ For chondral defects, a 15-mm graft is taken. For osteo­ tilage to a region of a chondral or osteochondral defect. chondral defects, a 25-mm graft is obtained . The chisel Lane et al.91 showed that the hyaline cartilage remains via­ is twisted to break the cancellous bone , and the graft is ble 12 weeks after transfer. However, two problems were removed. All grafts are harvested with a similar technique encountered witi l single plug osteochondral transfers: (Figure 17-25). donor site morbidity and surface incongruity at the recipi­ ent site . Mosaicplasty was developed in an attempt to mini­ mize these problems. Mosaicplasty involves the transfer of multiple small osteochondral plugs to a region of chondral or osteochondral defects. The use of multiple small grafts allows for maintenance of donor site integrity and contour­ ing of the new surface. Surgical Technique. Autologous osteochondral mosaicplasty involves harvesting and transferring small, cylindrical osteochondral grafts (2.7 to 8.5 mm in diame­ ter ) from the periphery of the femoral condyles at the level of the patellofemoral joint (Figure 17-24). The cylindrical grafts are then transplanted to pre pared recipient sites in the region of the chondral or osteochondral defect . Combination of different graft sizes allows for cover­ age of approximately 80% of the lesion . The areas between the osteochondral cylinders are filled with fibro­ cartilage . At the time of the procedure, a diagnostic arthroscopy is performed. The chondral or osteochondral defect is identified and inspected . All loose cartilage frag­ Figure 17-25 ments are debrided back to stable, normal articular Single osteoch ondral plug. 598 CHAPTER 17 • Injuries to the Meniscus and Articular Cartilage

and 79% of patients with patellar or trochlear defec ts. Three percent of patients reported donor site morbidity, and 4% reported painful postoperative hemarthroses. In contrast 95 to the findingsoft hese studies, Bentley et a1. reported that only 69% of patients had good or excellent clinical res ults as assessed by the modified Cincinnati and Stanmore scores. Painfulpostoper ative hemarthroses continue to be a signifi­ cant complication after mosaicplasty. Feczko et a1.96 used a German Shepherd model and tested donor site plugs. They fo und that compressed collagen minimized blood loss from the donor sites while still allowing grad ual substiultion with bone and fo rmation of a fibrocartilage cap at tile articular surface.

Autologous Chondrocyte Tr ansplantation Chesterman and Smitl197 first successfully isolated and grew chondrocytes in culture in 1965. They took epiphyseal chondrocytes from rabbits , grew them in culture, and then implanted tllem into artic ular defects in tile tibia . They did 8 Figure 17-26 not show any significant repair. In 1982, Grande et a1Y Defect fi lled with multiple osteochondral plugs. (From InsaU TN, Scott began growing articular chondrocytes in culture and then WN: Surgery of the knee, ed 3, p 358, New York, 2001, ChurchiU Livingsto ne. ) transplanting them into a patellar defect covered with a periosteal flap. These initial results were presented in 1984 and showed 80% filling of the defect with hyaline-like Attention is then turned to the recipient site. Recipient cartilage. In 1987, the first autologous chondrocyte trans­ tunnels are created with drill bits and then an appropriately plantation was performed in the human knee in Sweden . sized dilator. The grafts are inserted with an adjustable Brittberg et al.99 reported on the results of the first 23 pro­ plunger device . It is extremely importan t to ensure that a cedures. Fourteen of 16 patients with fe mo ral lesions had smooth surface is created , without prominent or sunken good or excellent results, whereas only two of 7 patients grafts (Figure 17-26). with patellar lesions had good or excellent results. After all grafts have been put in place, the knee is irri­ Surgical Technique. Autologous chondrocy te trans­ gated and all wounds are closed. Some surgeons place a plantation re quires two operative procedures. The first pro­ drain in the knee to try to prevent large postoperative cedure is a diagnostic arthroscopy and harvesting of hematomas. chondrocytes. The cultured chondrocytes are implanted Rehabilitation. Rehabilitation after osteochondral during tile second procedure. A diagnostic arthroscopy is autograft transp lan tation fo cuses on early re turn of range performed, and the chondral defect is assessed. The defect of motion and protected weight bearing. ROM exercises is not debrided. Any meniscal lesions should be dealt with can be initiated immediately after surgery. Patients are kept during tile first procedure. Once it has been decided that to toe touch weight bearing fo r 6 weeks to allow healing of the patient could benefit from autologous chondrocyte the bony portion of the graft. Patients are allowed to prog­ transplantation , cartilage is harvested , typically fro m the ress to weight bearing as tolerated after 6 weeks and can upper medial or upper lateral condy le of tile fe mur. Carti­ re turn to sports activity as soon as they have regained ade­ lage most often is taken fro m the upper medial condy le of quate range of motion and strength. the fe mur at the level of the patellofemoral joint. Three to Results. The results of multiple osteochondral auto­ fo ur slices of cartilage , 3 to 4 mm by 10 mm, sho uld be graft transplantation have been promising. Chow et a1.92 harvested down to subchondral bone. Two hundred to reported on 33 patients with 2 to 5 years fo llow-up. 300 mg of articular cartilage is re quired fo r enzymatic Eighty -seven percent of patients reported their knee as digestion and cell culturing . After harvesting of tile carti­ being normal or nearly normal using the International lage , the knee is irrigated, all arthroscopic instruments are Knee Documentation Committee (IKDC ) assessment. removed , and wounds are closed. Jakob et a1.93 reported on 52 patients with 2 to 5 year fo l­ The second procedure involves harvesting of a perios­ low-up. Ninety -two percent of patients had improvement teal flap and implantation of the cultured chondrocytes . 94 in knee fu nction at the final fo llow-up. Hangody et a1. A smal l peripatella r incision is performed to expose the reviewed 831 patients undergoing mosaicplasty. Good to chondral defect. The area of the defect is debrided, with excellent results were obtained in 92% of patients with fe m­ cut vertical edges creating an abrupt transition from oral condy lar defects, 87% of patients with tibial defects, healthy cartilage to de fect. The excised area is debrided Injuries to the Meniscus and Articular Cartilage • CHAPTER 17 599 down to subchond ral bone without ca using bleeding. If bleeding occurs from the subchondral bone, it must be stopped before implantation of the chondro cy tes. A sepa­ rate incision is made to harvest the periosteal flap, which usually is obta ined from the upper medial tibia. The peri­ osteal flap is sutured into the healthy cartilage surround­ ing the defect. The cambium layer of the flap must face the subchondral bone of the defect. Sutures are placed at 5- to 6-mm intervals, and intervals between the sutures are sealed off with fibrin gl ue. An opening is left in the periosteal patch for injection of the chondro cy tes. Afte r injection of the cell s, closure of the periosteal patch is completed with sutures and fibrin glue (Figures 17-27 to 17-29). Rehabilitation. Rehabilitation afteraut ologous chon­ drocy te tran splantation can be broken down into range of motion , CPM, weigh t bearing, strengthening, and func­ Figure 17-28 tional training. Patients can begin working on range of Completion of the periosteal patch. (From Insall IN, Scott WN: SUllfcry of the knee, p motion immediately after surgery. Trochlear groove ed 3, 349, New York, 2001, Churchill Livingstone . ) patients sho uld not work on active extension for the first 4 weeks, because as active extension increases patellofe­ mo ral con tact stresses. CPM should be used as much as possible for the first 6 weeks. Most patients should be non-weigh t-bearing for at least the first 2 weeks. Patients th en can progress to partial weight bearing. All patients sh ould be in a hinged knee brace that is locked in extension for ambulation. Femoral condyle patients can progress to weight bearing as tolerated at 6 weeks. Trochlear patients can progress to weight bearing as tolerated as soon as they are comfortable as long as they are in the knee brace locked in extension. This keeps the patella out of the trochlear groove and protects the repair. Strengthening can begin

Figure 17-29 Injectio n of chondrocytes beneath the periosteal patch. (From Insall IN, Scott WN : Surgery of the knee, ed 3, p 349, New York, 2001, Churchill Livingstone.)

Clinical Point

It is imperative that the surgeon inform the rehabilitation team of the range of motion to prevent loading, as determined from intraoperative viewing of the lesion during knee range of motion. This allows optimum rehabilitation and protection of the repair.

in the first 2 weeks with isometric quad riceps sets and

Figure 17-27 straight leg raises. Closed chain activities can be started at Periosteal patch being sewn into place. (From InsaJi IN, Scott WN: 6 weeks. Positions that stress the re gion of ch ondro cy te SUllferyoftheknee, ed 3, p 349, New York, 2001, Churchill Livingstone.) implanta tion should be avoided . For anterior femoral 600 CHAPTER 17 • Injuries to the Meniscus and Articular Cartilage condyle lesions, loading in full extension should be Biopsy specimens were obtained from 84% of patients . avoided . For posterior femoral condyle lesions, loacling in No histological difference was seen between the two flexion should be avoided . For trochlear lesions, deep groups . Horas et al. 102 compared AC I to osteochondral squats sho uld be avoided . Functional training can begin cylinder transplantation . Forty patien ts with isolated fem­ between weeks 8 and 12. oral defects were randomized to AC I or osteochondral cylinder transplantation . Us ing Lysholm scores, recovery from AC I was slower than recovery from osteochondral Positions to Avoid with Autologous Chondrocyte cylinder transplantation . After 2 years, clinical results were Transplantation equal between the two groups . Histomorphological exam­ ination of the AC I patients showed a stable resurfacing of • Anterior femoral condyle lesions-avoid full extension the defect in all patients . The tissue consisted mainly of • Posterior femoral condyle lesions-avoid loaded flexion • Trochlear lesions-avoid deep squats fibrocartilage , with localized areas of hyaline-like regener­ ative cartilage close to the subchondral bone. Examination of biopsies from the osteochondral cylinder transplanta­ tion showed remaining gaps between the graft and intact Low impact activities, such as cycling, roller blading, and articular cartilage , but no histological difference was seen skating, can be started 9 to 12 months after surgery. Repet­ between the osteochondral transplan ts and the surround­ itive impact loading, such as jogging and aerobics, can be ing original cartilage . started at 13 to 15 months, and high level sporting activ­ Numerous stuclies have shown that autologous chon ­ ities can be star ted 16 to 18 months after surgery. drocyte transplantation provides good to excellent results Results. The results of autologous chondrocyte trans­ in 80% to 90% of patients with isolated chondral defects plantation have been quite promising . Peterson et al .lOO of the femoral condyles . Results are less preclictable for reported on 101 patients treated with ACI with 2 to 9 year patellar or trochlear defects . Autologous chondrocyte follow-up. Ninety -two percent of patients with isolated transplantation is one option in the treatment of chondral femoral lesions had good or excel lent results . Sixty -five per­ defects in the knee . cent of patien ts with patellar defects had good to excellent results. Second look arthroscopy was performed in 53 patients. Of these, 26 had a hyperu"ophic response of the periosteum or graft. Seven of these 26 were symptomatic . Summary lOl The incidence of graft failure was 7%. Peterson et al . fol­ The treatment of chondral injuries has become an increas­ lowed a group of 61 patients treated for isolated femoral or ingly popular field. As outlined in th is chapter, a number patellar defects for 5 to 11 years to determine the durability of different options are available to today 's ortllopedic sur­ of the repair tissue . At 2 years, 50 of 61 patients had good geon . The clifferent techniques have vary ing advantages to excellent results. At 5 to 11 year follow-up, 51 of 61 and clisadvantages . The rehabilitation team needs to under­ patients had good to excellent results. stand tlle biology of tlle repair techn ique, the biomechanics Several studies have been performed to evaluate the of the knee , and how tlle location of the chondral defect outcome of ACI compared to the outcomes with micro­ affects the biomechanics in order to develop the best reha­ 90 fracture and mosaicplasty . Kn utsen et a1. compared bilitation program and offer the best rehabilitation advice ACI to microfracture in a randomized trial . Eighty to each patient. patients with a single chondral defect in the femoral con­ dyle were randomized to AC I or microfracture . Indepen ­ dent observers performed follow-up examinations at 12 References and 24 months . Second look arthroscopy was performed at 2 years . Histological evaluation was performed by a To enhance this te xt and add value for the reader, all refer­ pathologist and a clinical scientist , both of whom were ences have been incorporated into a CD-ROM tllat is blinded to each patient 'S treatment . Both groups showed provided with tllis text . The reader can view ·tlle reference improvement at 2 years, but the microfracture group had source and access it online whenever possible . There are a slightly better improvement as measured by the SF -36. total of 102 references for tllis chapter.