The Acutely Dislocated Knee: Evaluation and Management

A 2 Most 6,8,13,14 Anatomic classification recent advances have cen- 16 15 3 weeks). ≥ (within 3 weeks of injury). Classification Knee dislocation is temporallysified clas- as acute (<3 weeks)( or chronic Dr. Rihn is ResidentOrthopaedic Physician, Surgery, Department University of ofMedical Center, Pittsburgh Pittsburgh, PA. Dr. Groff is Clin- ical Fellow, Center for Sportssity Medicine, of Univer- Pittsburgh, Pittsburgh. Dr. Harner is Blue Cross of Western Pennsylvania Professor, and Di- rector, Section for Sports Medicine,of Department Orthopaedic Surgery, University of Pittsburgh Medical Center. Dr. Cha isBeacon Attending Orthopaedics and Surgeon, Sports Medicine,cinnati, Cin- OH. None of the following authors orwith the which departments they are affiliated has received anything of value from or owns stockpany in a or commercial institution com- related directlyto or the subject indirectly of thisDr. article: Harner, Dr. and Rihn, Dr. Dr. Groff, Cha. Reprint requests: Dr. Harner, CenterMedicine, for 3200 Sports South Water Street,PA Pittsburgh, 15203. Copyright 2004 byOrthopaedic the Surgeons. American Academy of tered on improvementstechnique. in surgical is based on theplaced position tibia of (ie, themedial, anterior, dis- or posterior, lateral) on the femur. of the principlesmanagement of of evaluation the and patientacutely with dislocated an knee aretablished; well es- Surgical timing, graft 9-13 The goal of surgical man- Some advocate delayed Journal of the American Academy of Orthopaedic Surgeons 6-8 9,12,13 Historically, traumatic dislocation of the knee hasprolonged been immobilization, managed which has with been associated withcomes, variable including loss out- ofsidual motion, re- instability,function. and poor knee to the collateral ligaments,articular menisci, cartilage, and neurovascular structures can complicate the evaluation and treatment ofwith the a patient traumatic knee dislocation. agement of acute dislocationsatomic is an- repair and reconstructionall associated of ligamentous and meniscal injuries. selection, and surgical technique remain controversial. Thelograft use has become of populartiligament al- in knee mul- surgery becausegraft availability, decreased of operating time, and decreased donor sitebidity mor- inknee. an already traumatized surgery, but many others recommend early surgical repair or reconstruction J Am Acad Orthop Surg 2004;12:334-346 Evaluation and Management The Acutely Dislocated Knee: These data 1-3 Associated injuries 4,5 Jeffrey A. Rihn, MD, Peter S. Cha, MD, Yram J. Groff, MD, and Christopher D. Harner, MD Knee dislocation commonly in- 334 Traumatic knee dislocations are uncommon, accounting for <0.02% of all orthopaedic injuries. Abstract Acute knee dislocations are uncommon orthopaedictaneously injuries. Because reduce they often before spon- initialcation evaluation, involves the injury true totional incidence multiple instability. is ligaments Associated unknown. of meniscal, Dislo- theare osteochondral, knee, often and present resulting neurovascular and in injuries ated can multidirec- vascular complicate injury mandates management. that The vascularin substantial integrity all be suspected risk confirmed knee of by dislocations. angiography associ- formed Evaluation expeditiously and to initial prevent limb-threatening management complications. must Definitivement be manage- per- of acute knee dislocationstruction remains or a repair matter of all of ligamentous debate;of injuries however, likely surgical adequate can recon- help knee in function. achievingclude the surgical Important timing, return graft considerations selection, surgical in technique, and surgical postoperative rehabilitation. management in- likely underestimate thedence because true an unknown inci- percent- age of knee dislocations spontaneously reduce and thus are not diagnosed during the initialmanagement evaluation. of Mis- have such devastating consequences, par- injuriesticularly can in dislocations that involve limb-threatening vascularTherefore, injuries. despite the lowincidence reported of knee dislocation, a basic knowledge of current evaluation and management concepts is essential. volves injury to most of the soft-tissue stabilizing structures of the knee, resulting in multidirectional instability.Although knee dislocation can occur involving injury isolatedanterior to cruciate the ligament (ACL)posterior or cruciate ligamentboth of the cruciate (PCL), ligaments are usually disrupted.

Downloaded from http://journals.lww.com/jaaos by BhDMf5ePHKav1zEoum1tQfN4a+kJLhEZgbsIHo4XMi0hCywCX1AWnYQp/IlQrHD3i3D0OdRyi7TvSFl4Cf3VC4/OAVpDDa8KKGKV0Ymy+78= on 02/25/2021 Downloaded from http://journals.lww.com/jaaos by BhDMf5ePHKav1zEoum1tQfN4a+kJLhEZgbsIHo4XMi0hCywCX1AWnYQp/IlQrHD3i3D0OdRyi7TvSFl4Cf3VC4/OAVpDDa8KKGKV0Ymy+78= on 02/25/2021 Jeffrey A. Rihn, MD, et al rotatory knee dislocation involves a with knee dislocation until it is proved looked when evaluating a multiply combination of these tibial displace- otherwise by angiography. traumatized patient. Thus, even with ment positions. Knee dislocations that Neurologic damage, ranging from normal-appearing radiographs, a spontaneously reduce before evalu- a stretching of the nerve (neurapraxia) complete physical examination of the ation are classified according to the to complete transection (neuronotme- knee, including thorough neurovas- direction of instability. sis), occurs in 16% to 40% of all knee cular assessment, is essential for all Anterior dislocations are the most dislocations; it is most common after victims of high-energy trauma. When common, accounting for approximate- posterolateral dislocations.6,20 The pe- substantial laxity of two or more of ly 40% of all knee dislocations.17 Hy- roneal nerve is more often injured than the major ligaments of the knee is perextension is typically the mecha- the tibial nerve.21 Careful neurologic found, a presumptive diagnosis of nism of injury. Posterior dislocations examination before any manipulation knee dislocation should be made. represent 33% of all knee dislocations.17 of the knee is mandatory, although it The vascular examination includes The mechanism is usually high energy, is often difficult to obtain, particular- manual palpation of the dorsalis pe- such as the so-called dashboard in- ly in a trauma patient. dis and posterior tibialis pulses and jury sustained during a motor vehi- comparison with the uninvolved side. cle accident. Lateral and medial dis- The ankle-brachial indices (ABI) de- locations are less common, estimated Evaluation termined with ultrasound is a more at 18% and 4% incidence, respective- sensitive study that can help confirm ly.17 The mechanism involves a vio- Initial assessment of the patient be- the vascular status of the extremity. lent varus or valgus load. Associated gins with a brief history that reviews An abnormal result from any of these fractures are not uncommon. Rotatory the mechanism of injury and a direct- tests should prompt a vascular sur- knee dislocations, caused by a twist- ed physical examination that includes gery consultation. However, a normal ing force to the knee, are the least com- a thorough neurovascular evaluation result from any of these tests does not mon type. Posterolateral dislocations, of the injured extremity. The patient exclude arterial injury. Normal puls- the most common type of rotatory knee with a dislocated knee usually has a es, a warm foot, and brisk capillary dislocation, have a high incidence of tremendous amount of pain, a large refill can be present with arterial in- irreducibility, in which case the me- knee effusion, and overall swelling of jury. Therefore, any patient with a dial femoral condyle buttonholes the extremity. A spontaneously re- high suspicion of knee dislocation through the medial soft-tissue struc- duced knee dislocation can appear should undergo arteriography of the tures.18 deceptively benign and can be over- lower extremity (Fig. 1). The routine

Associated Neurovascular Injuries

Injuries to the popliteal artery can make knee dislocation a limb-threatening emergency. The reported incidence of associated popliteal artery injury is between 32%17 and 45%,19 with severity ranging from an intimal tear to complete transection. Because amputation rates vary in direct relation to the length of time to revascularization, immediate recognition of arterial vascular compromise is cru- cial. An amputation rate of 86% after a delay in revascularization of 6 to 8 hours has been reported.17 Damage to the intimal portion of the artery can be more insidious, with delayed vascular compromise presenting sever- Figure 1 Anteroposterior arteriograms of an intact popliteal artery (A) and an injured popliteal al days after the injury. Vascular in- artery (B) after acute knee dislocation and subsequent reduction. The artery shown in panel B was found to be transected at exploration. jury must be assumed in all patients

Vol 12, No 5, September/October 2004 335 The Acutely Dislocated Knee: Evaluation and Management use of arteriography in this setting is justified by the relatively low morbidity of the test, the high incidence of popliteal artery injury, and the potentially devastating consequences of delay in diagnosis.20,22-24 A complete neurologic examination also must be performed, including an evaluation of motor and sen- sory function in the distribution of the tibial and peroneal nerves. The por- tions of the examination requiring patient cooperation are often difficult to obtain and should be accurately documented. Progressive deteriora- tion of neurologic function raises the suspicion of an impending compartment syndrome or ischemia. The examination of knee stability should be done only after survival of the limb is ensured. It should be done as gently as possible to avoid iatrogenic injury. Thorough evaluation of all ligaments can be difficult to obtain because of the associated pain. The most sensitive test for determining ACL deficiency is the Lachman test, performed with the knee held in 20° to 30° of flexion.25 The most sensitive test for detecting PCL injury is the posterior drawer test, performed with the knee in 90° of flexion.26 To accurately assess the PCL, the normal step-off of the medial tibial plateau in reference to the medial femoral condyle must be determined. The collateral ligaments are assessed by applying stress in the coronal plane at both full extension and 30° of knee flexion. Standard radiographs are obtained to evaluate the direction of dislocation, characterize associated osseous Figure 2 Anteroposterior (A) and lateral (B) radiographs of a posterolateral knee dislocation in a patient who sustained a twisting injury to the left knee while playing basketball. injuries (ie, fracture or avulsion), and Anteroposterior (C) and lateral (D) radiographs of the same knee after closed reduction un- confirm reduction (Fig. 2). Initial ra- der conscious sedation and placement in a long leg plaster splint. diographs should be obtained immediately after a prompt evaluation of the patient. Magnetic resonance imaging (MRI) can be used to charac- Initial Management duced immediately through gentle terize associated soft-tissue and occult traction-countertraction with the pa- osseous injuries only after the patient The vascular status of the limb must tient under conscious sedation. The has been acutely stabilized (Fig. 3). be determined quickly and managed limb should then be stabilized in a MRI is helpful in developing a sur- appropriately. If the limb is obvious- long leg splint. If pulses are restored gical plan. ly ischemic, the knee should be re- with the reduction, postreduction ra-

336 Journal of the American Academy of Orthopaedic Surgeons Jeffrey A. Rihn, MD, et al

Emergent Surgery

Emergent surgery is indicated in patients with vascular injury, compartment syndrome, open injury, or irreducible dislocation. Patients with a popliteal artery injury require emergent intervention by a vascular surgeon. Input from the orthopaedic surgeon concerning the location of future incisions can help optimize recon- structive efforts. Saphenous vein grafting and fasciotomies are often required after revascularization. Even without vascular compromise, a compartment syndrome is a surgical emergency. Despite the presence of a knee dislocation, prompt diagnosis and management of a compartment syndrome is mandatory for successful resolution. In open knee dislocation, the standard principles of wound management prevail, including initial irriga- tion and débridement, with serial débridements as needed as well as in- travenous antibiotics and adequate soft-tissue coverage. Early ligament reconstruction is contraindicated with an open wound. In some instances, soft-tissue coverage problems may Figure 3 T1-weighted (A) and T2-weighted (B) sagittal MRI scans of the left knee of a pa- delay ligament reconstruction for sev- tient who sustained a twisting injury from stepping in a hole during a softball game. The images show disruption of both the anterior (arrow) and posterior (arrowhead) cruciate lig- eral months. aments. C, T1-weighted sagittal image showing an injury to the lateral meniscus (asterisk), Irreducible dislocations are un- which appears to be elevated off the lateral tibial plateau. D, T2-weighted coronal image show- common, but they require prompt ing injuries to the lateral meniscus (asterisk) and posterolateral corner (solid circle). The fibular head appears comminuted, and there is no identifiable lateral collateral ligament, bi- surgical reduction to avoid prolonged ceps femoris tendon, or popliteus tendon. traction on the neurovascular structures. Although ligament reconstruction can be done at the time of open diographs and a formal angiogram and the knee is promptly reduced. A reduction, it is preferable to delay de- should be obtained. If the limb re- gentle reduction maneuver is prefer- finitive reconstruction to allow for mains ischemic, the patient requires able, avoiding extreme deformity of complete knee imaging, planning, emergent surgical exploration and re- the limb to minimize the likelihood and resource mobilization. vascularization in the operating of iatrogenic vascular injury. Ade- During emergent surgery on a dis- room. More rigid stabilization can be quate sedation is important. The spe- located knee, however, it is acceptable applied in the form of external fixa- cific reduction technique depends on to perform simple repairs as they are tion that spans the knee joint, with the direction of the dislocation, but encountered in the surgical exposure. pins in the femur and tibia. The ex- the most important element is distrac- Use of excessive foreign material, internal fixator supplies sufficient rigid- tive force. After reduction, a repeat cluding suture, should be avoided in ity to maintain reduction but allows neurovascular examination is done open injuries, and additional inci- good access to the knee and leg for and radiographs are obtained. As sions solely for reconstruction should serial neurovascular examinations. with all cases of knee dislocation, an- not be done. In almost all circum- When there is no vascular compro- giography should be done to rule out stances, definitive ligament recon- mise, radiographs should be obtained vascular injury. struction should be delayed for sev-

Vol 12, No 5, September/October 2004 337 The Acutely Dislocated Knee: Evaluation and Management eral days to allow limb swelling to ment of knee dislocation is well doc- Timing subside. With vascular injury, time is umented.7,8,34 When there is no need for emer- required to ensure that the vascular Nonsurgical management begins gent surgery, surgical intervention repair is adequate. with 6 weeks of immobilization in ex- should be delayed until adequate per- tension. The form of immobilization fusion of the limb is ensured and all depends on several clinical factors; factors have been optimized to allow Definitive Management choices include a cast, brace, external safe surgical repair. Delaying surgery fixator, or transarticular Steinmann for 10 to 14 days offers several advan- The management of multiligamen- pin. If vascular repair was done, a cast tages. It allows for a period of vas- tous knee injuries has not been well or brace should not be used in order cular monitoring and the resolution studied and remains controversial. to avoid circumferential pressure on of acute inflammation and soft-tissue Definitive conclusions are difficult to the limb. External fixation can pro- swelling. Range of motion (ROM) and make because of the relative infre- vide more protection to the vascula- quadriceps muscle tone will partial- quency of these injuries, the many ture. For the extremely obese patient, ly return, potentially reducing the risk combinations of ligamentous and me- immobilization often is not possible of postoperative arthrofibrosis.10 Var- niscal injury patterns, the varied treat- with a cast or brace alone. Therefore, ious degrees of healing occur. The ment approaches, and the numerous external fixation is a viable option for capsule heals quickly and may allow methods of outcomes assessment. Be- the extremely obese patient. an arthroscopically assisted approach fore the mid 1970s, nonsurgical man- The ideal flexion angle in which to that minimizes the extent of dissec- agement consisting of closed reduc- immobilize the dislocated knee has tion. tion followed by immobilization was not been well studied. The ACL- Delaying surgery beyond 3 weeks, common.2,7,27,28 Results tended to vary deficient knee is more stable in flex- however, results in excessive scarring with the duration of closed treatment: ion, and the PCL-deficient knee more of the collateral ligaments and pos- longer periods of immobilization re- stable in full extension. Knee flexion terolateral structures that may pre- sulted in stable but stiff knees, where- of 30° to 45° is usually sufficient. Ir- clude their repair. If surgery must be as brief periods led to excellent mo- respective of the angle selected, main- delayed beyond 3 weeks, it may be tion but greater instability.6,7,29,30 taining a reduced tibiofemoral joint prudent to wait until full ROM is es- Unfortunately, no prospective study is essential. Nonsurgical management tablished and to consider late recon- compares surgical with nonsurgical demands frequent radiographs, espe- struction only if the patient develops management options for this type of cially in the first few weeks, to ensure residual laxity and functional insta- injury. With recent advances in knee that the joint remains in the reduced bility. ligament surgery, however, surgery is position. Immobilization is followed often recommended for the patient by rehabilitation with progressive Procedure with knee dislocation.8,9,13,15,29-32 The motion in a brace. Initiation of light The patient is positioned supine on goal of surgery is to improve stabil- running is highly variable, with most the operating table with a well- ity, retain motion, and achieve knee patients reaching this point at 6 to 8 padded tourniquet applied to the function that allows the patient to months. upper thigh; the tourniquet is not in- perform daily activities. flated during the procedure unless necessary. A sandbag, on which the Surgical Management foot is rested when the injured knee Nonsurgical Management is flexed, is secured to the operating Most authors currently recommend table at the level of the midthigh. A Although used frequently in the past, surgery for acute knee disloca- lateral post is placed at the level of closed reduction and cast immobili- tion.8,9,13,15,29-32 Controversies persist the tourniquet to prevent lateral zation is now indicated only for pa- regarding surgical timing, surgical movement of the flexed leg. The set- tients who are elderly or sedentary or technique (ie, which structures to re- up should permit the knee to be tak- who have debilitating medical or post- construct or repair), graft selection, en through a full ROM. A Doppler ul- traumatic comorbidities.7,33 Those who and rehabilitation. Generally, simul- trasound is used to confirm the distal initially undergo a trial of nonsurgi- taneously repairing both the ACL and pulses at the beginning and end of cal management often require surgi- PCL as well as any grade III collat- surgery. cal intervention later to address prob- eral or capsular injuries is the most After appropriate patient position- lems with knee function, including loss reliable method of restoring ligamen- ing, an examination under anesthe- of motion or persistent instability.Poor tous stability, knee motion, and over- sia is performed. It is important to outcome after nonsurgical manage- all knee function. completely define all ligamentous in-

338 Journal of the American Academy of Orthopaedic Surgeons Jeffrey A. Rihn, MD, et al juries and ROM. Special attention is wound breakdown while providing ber and extent of incisions in an al- paid to the collateral ligaments because satisfactory exposure. ready traumatized knee.12,41,42 Allograft injuries to these structures generally use also decreases intraoperative tour- determine which surgical incisions are Repair Versus Reconstruction niquet time, postoperative pain, and used. The contralateral knee is used The decision to repair or reconstruct postoperative knee stiffness.41 Disad- for comparison. Proposed skin inci- a torn ligament depends on several vantages of allograft tissue compared sions are marked and injected with factors. Most cruciate injuries in knee with autograft tissue include greater 0.5% bupivacaine with epinephrine. dislocations are midsubstance tears cost, risk of disease transmission, and To decrease the amount of sur- that are not amenable to successful delay in graft incorporation and re- gical dissection, arthroscopic tech- surgical repair.37,38 Some surgeons modeling.43,44 niques are used as much as possible. reconstruct midsubstance tears of the Bone–patellar tendon–bone (BPTB) However, it is not always possible or cruciate ligaments with allograft. Suc- allograft is recommended to reconstruct safe to use arthroscopy in the acute cessful repairs can be done in cases the ACL. The BPTB graft provides ad- setting because of capsular disrup- of bony avulsion,39,40 either by using equate strength and rigid bony fixation. Sufficient capsular healing (ap- nonabsorbable sutures passed through tion at both the tibial and femoral at- proximately 2 weeks) is needed to small drill holes tied over a cortical tachment sites. Use of cylindrical bone maintain joint distension and avoid bridge of bone or by achieving screw plugs 11 mm in diameter × 25 mm in iatrogenic compartment syndrome. fixation, depending on the size of the length with an 11-mm tendon width The procedure is begun using grav- associated bone fragment. is preferred. To facilitate graft passage, ity inflow. The thigh and calf must be For the MCL and posterolateral two no. 5 nonabsorbable sutures are palpated intermittently throughout structures, primary surgical repair in placed in both the patellar and tibial the procedure to monitor fluid ex- the acute setting (<3 weeks) yields plugs through drill holes. For PCL re- travasation. If extravasation is noted, satisfactory results. During this time, construction, Achilles tendon allograft the arthroscopic technique is aban- avulsions or intrasubstance tears of can be used alone or in combination doned and the remainder of the sur- the MCL may be directly repaired. with an ipsilateral hamstring tendon gery is done with an open technique. Similar intrasubstance tears of the as an autograft for a single-bundle or In this situation, the arthroscope can LCL also can be repaired but may double-bundle technique, respectively. still be valuable in a dry field because need to be supplemented with al- Achilles tendon allograft is effective it can improve visualization as the lograft tissue. Beyond 3 weeks, scar for PCL reconstruction because of its procedure is done through miniar- formation and soft-tissue contracture cross-sectional area and calcaneal bone throtomies. limit the success of primary ligamen- plug that allows rigid bony fixation tous repair, often making reconstruc- at the femoral attachment site. Com- Approach tive procedures necessary. paction pliers and a rongeur are used The pattern of injury dictates the The articular cartilage and menis- to size the central portion of the cal- surgical approach. The two most ci should be inspected arthroscopically caneal bone plug to a diameter of 11 common combined injury patterns in- to define pathology not appreciated mm and a length of 25 mm. Two no. clude either the ACL, PCL, and me- on physical examination or in imag- 5 nonabsorbable sutures are placed in dial collateral ligament (MCL), or the ing studies. Peripheral meniscal tears the bone plug. The tendinous end of ACL, PCL, lateral collateral ligament are repaired directly; central or irrep- the graft is tubularized with a double- (LCL), and posterolateral structures. arable meniscal lesions are débrided armed no. 5 nonabsorbable suture us- Less commonly, the PCL is intact or to a stable rim while preserving as ing a baseball whipstitch, which pre- is only partially disrupted and does much meniscus as possible. vents the graft from “balling up” not require reconstruction.5,35 The pat- during graft passage. The LCL is re- tern of injury determines placement Graft Selection and Preparation constructed with an Achilles tendon of the skin incisions. Some authors Several different grafts may be used allograft with a 7- or 8-mm–diame- advocate the use of a midline incision, for reconstruction. Depending on the ter calcaneal bone plug. Alternatively, which provides limited access to the extent of injury, autograft tissue may the BPTB allograft remaining from the collateral ligaments and can be com- be obtained from the ipsilateral or con- ACL graft may be used for the LCL plicated by skin sloughing over the tralateral extremity.However, allograft reconstruction. Either tibialis anterior patella. The medial and lateral hock- tissue has advantages over autografts tendon allograft or ipsilateral ham- ey stick incisions described by Hugh- in knees with multiple ligament in- string tendon autograft can be used ston and Jacobson36 and Muller,37 juries. The use of allograft tissue elim- to reconstruct the popliteofibular lig- when separated by at least 10 cm, inates graft site morbidity, decreases ament. These grafts are prepared to minimize the risk of skin necrosis and dissection time, and reduces the num- a diameter of 7 mm and secured with

Vol 12, No 5, September/October 2004 339 The Acutely Dislocated Knee: Evaluation and Management a no. 2 nonabsorbable suture using a whipstitch on both ends.

Cruciate Ligament Reconstruction The details of reconstructing the ACL and PCL have been well described.45-48 The femoral and tibial insertions of the cruciate ligaments are identified arthroscopically. The femoral PCL tunnels are placed to re- produce the anterolateral bundle of the native PCL, whereas the ACL tunnels are placed in the center of its anatomic insertions (Fig. 4). In the setting of acute knee dislocation, a transtibial tunnel technique for PCL reconstruction is safer than the tibial inlay technique; the tibial inlay technique requires extensive soft-tissue dissection, and there is increased risk Figure 4 Anteroposterior (A) and lateral (B) views showing tunnel placement in combined PCL and ACL reconstruction. of vascular injury associated with the posterior approach. Some technique modifications are helpful for multi- ligament reconstruction after knee ial cortical bridge remains after drill- to ensure proper placement of the dislocation. One order of bicruciate ing. Because the PCL is absent, the ACL tibial tunnel. Intraoperative ra- reconstruction is outlined in Table 1. posterior edge of the anterior horn of diographs or fluoroscopy images are the lateral meniscus is used as a guide obtained to monitor guidewire place- Tibial and Femoral Tunnels to the center of the tibial footprint of ment (Fig. 5). The PCL tibial tunnel is drilled the ACL. The guidewire should be di- The PCL tunnel is drilled using a first, with placement of a 15-mm off- rected posterior to Blumenstaat’s line 10-mm compaction drill bit under di- set PCL guide set at 50° through the on the full extension lateral projection rect arthroscopic control. A30° arthro- anteromedial portal. The tip of the PCL guide is positioned in the distal and lateral third of the tibial PCL in- Table 1 sertion site. A 1.8-mm guidewire is Order of Bicruciate Ligament Reconstruction in the Dislocated Knee started 4 cm distal to the joint line and 2 cm medial to the tibial tubercle and Step 1 Drill tibial tunnels PCL, then ACL placed under arthroscopic guidance using the PCL guide. The guidewire Step 2 Drill femoral tunnels ACL, then PCL should exit through the tibial PCL Step 3 Graft passage and Pass and fix PCL bone block into femoral femoral fixation tunnel through the anterolateral portal footprint approximately 1 cm below Pass tendinous portion of PCL graft into the tibial plateau. Caution must be tibial tunnel taken when passing the guidewire Pass ACL graft through tibial tunnel and through the PCL tibial insertion site fix in femoral tunnel because of the close proximity of the Step 4 Collateral ligament Secure extra-articular repairs or recon- neurovascular structures. repair structions The ACL tibial guide is set to 47.5° Step 5 PCL fixation: Tibia Fix PCL graft on tibia at 90° of flexion with and introduced through the antero- reproduction of anteromedial step-off medial portal. A 1.8-mm guidewire is Step 6 ACL fixation: Tibia Fix ACL graft on tibial side at full extension placed through the center of the ACL ACL = anterior cruciate ligament, PCL = posterior cruciate ligament tibial footprint. It exits at least 2 to 3 (Adapted with permission from Cole BJ, Harner CD: The multiple ligament injured knee. cm proximal to the PCL guidewire to Clin Sports Med 1999;18:241-262.) ensure that an adequate medial tib-

340 Journal of the American Academy of Orthopaedic Surgeons Jeffrey A. Rihn, MD, et al

of the notch in the center of the anatomic insertion of the ACL, located 6 mm anterior to the posterior wall of the femur at the 10 o’clock position (right knee) or 2 o’clock position (left knee).50 The guidewire is over- drilled with a 9-mm compaction drill to a depth of 25 to 35 mm, and dilators in 0.5-mm increments are used to expand the tunnel to a diameter of 10 mm. This technique can be de- manding because visibility is limited with the knee in full flexion. A two-incision technique for PCL graft tunnel placement with a separate femoral incision for outside-in drilling of the femoral tunnel can be used, but it is preferable to drill the femoral PCL tunnel through the anterolateral portal. With the scope in the anteromedial portal, the footprint Figure 5 Intraoperative lateral radiograph of the anterolateral bundle of the PCL Figure 6 Passage of the Achilles tendon al- taken after placement of ACL (top wire) and lograft for PCL reconstruction using the two- PCL (bottom wire) tibial tunnel guidewires. is easily visualized on the medial fem- incision technique. The Achilles tendon al- oral condyle. A guidewire is then lograft is passed from the femur to the tibia placed 7 to 10 mm from the articular to position the calcaneal bone plug in the femoral tunnel. surface within this footprint. A 10- mm compaction drill bit is used to scope is placed through the postero- drill the tunnel to a depth of 25 to 30 medial portal, and a curette is used mm. Bone debris is removed, and the ial tunnel to exit on the anteromedial to stabilize the Kirschner wire during tunnel is dilated to a diameter of 11 tibia. The calcaneal bone plug is drilling. The initial drilling is started mm using dilators in 0.5-mm incre- passed through the anteromedial fe- by power and completed by hand to ments. Double-bundle PCL recon- mur using a Beath needle placed minimize the risk of plunging through struction is not routinely done in through the PCL femoral tunnel to the posterior tibial cortex. Although acute knee dislocations. exit in the anteromedial thigh. A intraoperative fluoroscopy can be probe is used under arthroscopic used, direct visualization provides bet- Graft Passage and Femoral Fixation guidance to facilitate passage of the ter control. The PCL tibial tunnel is The PCL graft is passed first. Us- calcaneal bone plug. The calcaneal expanded to a diameter of 11 mm using the two-incision transtibial tun- bone plug is secured within the fem- ing dilators in 0.5-mm increments. The nel technique for PCL reconstruction, oral tunnel using an interference ACL tibial tunnel is then drilled us- the graft is passed from the femur to screw. If interference screw fixation ing a 9-mm compaction drill bit and the tibia, and the calcaneal bone plug is not possible, a separate femoral in- is expanded to a diameter of 10 mm is secured on the femoral side with cision is made, and the no. 5 nonab- using dilators in 0.5-mm increments. an interference screw (Fig. 6). Using sorbable suture attached to the calca- The femoral tunnels are created in the one-incision transtibial tunnel neal bone plug is tied over a plastic the opposite order: ACL, then PCL. technique for PCL reconstruction, a button. The ACL graft is then passed The ACL femoral tunnel is drilled long looped 18-gauge wire is passed retrograde from the tibial to femoral through the anteromedial portal with retrograde into the PCL tibial tunnel tunnel using a Beath needle and is the knee in full flexion.49 This is pref- and retrieved from the anterolateral secured on the femoral side with a erable to the more traditional transtib- portal with a pituitary rongeur. The 7 × 25-mm interference screw. ial technique because the location of no. 5 suture secured to the tendinous the femoral tunnel is not constrained portion of the graft is passed into the Final Fixation by the position or angulation of the joint using the looped 18-gauge wire The tibial sides of the grafts are not tibial tunnel. The femoral tunnel can through the anterolateral portal, then secured until after the collateral lig- be placed more easily toward the wall passed antegrade down the PCL tib- ament injuries are addressed. Extra-

Vol 12, No 5, September/October 2004 341 The Acutely Dislocated Knee: Evaluation and Management articular repairs or reconstructions stick incision is made at the level of cision is made over the lateral epi- are secured with slight internal rota- the vastus medialis muscle and is condyle. It begins midway between tion for posterolateral structures and brought over the femoral epicondyle the fibular head and Gerdy’s tuber- with valgus force on the tibia for lat- to the anteromedial tibia just medial cle and then continues proximally eral collateral ligament repairs. Once to the patellar tendon (Fig. 7). The sar- over the lateral epicondyle, parallel- collateral surgery is completed, the torius fascia is split and reflected to ing the posterior border of the iliotib- cruciate grafts are fixed to their re- expose the MCL and capsule. Periph- ial band (ITB) (Fig. 8). The peroneal spective tibial attachment sites. In eral tears of the medial meniscus are nerve is identified and tagged with contrast to isolated cruciate ligament repaired through this approach using a vessel loop. It is easiest to locate the reconstruction, cyclic loading of the nonabsorbable sutures; the MCL is re- nerve proximally, posterior to the bi- grafts is not performed before final paired with nonabsorbable sutures ceps femoris tendon, and trace it dis- fixation. The tenuous repair or recon- and suture anchors. MCL and capsu- tally to its entrance into the anterior struction of other injured structures lar avulsions are repaired anatomical- compartment of the leg. The nerve is of the knee precludes rigorous pre- ly with suture anchors, whereas in- carefully evaluated and is usually re- tensioning of the cruciate grafts. Rath- trasubstance MCL tears are repaired leased as it passes around the fibu- er, the knee is taken through gentle with no. 2 nonabsorbable sutures us- lar neck. If a nerve injury is present ROM before final fixation to ensure ing a modified Kessler stitch.37 In the preoperatively, the extent of damage that the reconstructed knee has not chronic setting, reconstruction with a is noted. A formal neurolysis is usu- been captured. The PCL graft is ten- semitendinosus tendon or Achilles ally not done, but the fascial bands sioned and fixed to the tibia while re- tendon allograft may be required in at the entrance to the anterior com- producing the normal step-off of the addition to repair. The repair or re- partment of the leg are released if a medial tibial plateau in relation to the construction is done with the knee in neurologic deficit is present at the femoral condyle. The graft is fixed 30° of flexion. The knee is flexed and time of surgery. with a 10 × 30-mm bioabsorbable in- extended during repair to ensure that All of the posterolateral structures terference screw and/or a 4.5-mmAO knee motion is not constrained. The are then systematically evaluated. In screw with a soft-tissue washer with cruciate ligaments are then fixed on acute injuries, there may be signifi- the knee held in 90° of flexion to re- the tibial side, as described, and the cant stripping and detachment of create the anterolateral bundle. This knee is braced in full extension. both ligaments and tendons. The in- reestablishes the central pivot of the terval between the posterior edge of knee. With the knee in full extension, Lateral Side Injury the ITB and the biceps femoris ten- the ACL graft is then secured with a After the cruciate ligament graft don is developed. The ITB insertion 7 × 25-mm interference screw. passage, a 12- to 18-cm curvilinear in- also can be partially released subper-

Medial Side Injury For combined ACL-PCL-MCL injuries in which the medial side opens in full extension, a combined cruciate ligament reconstruction and MCL repair is performed. The MCL does not require repair if the knee does not exhibit a grade III MCL injury in full extension during the examination under anesthesia. In patients with grade III MCL injury, the cruciate tunnels are created arthroscopically before the medial side repair is done. In the acute setting with marked MCL in- sufficiency and extreme valgus laxity, arthroscopy may be impossible because of ﬂuid extravasation. In such cases, a medial hockey stick incision Figure 7 Medial approach to a knee dislocation involving injury of the ACL, PCL, and MCL. and the arthroscope (without ﬂuid) This patient also had an associated injury to the medial meniscus that required repair. are used to guide tunnel placement. A, Incisions for medial approach. B, Medial approach with guidewires present for drilling ACL and PCL tunnels and exposure of medial joint line for meniscus repair. For MCL repairs, a medial hockey

342 Journal of the American Academy of Orthopaedic Surgeons Jeffrey A. Rihn, MD, et al

tomic femoral insertion site of the popliteus tendon (Fig. 10). Its femoral attachment is then tied over a plastic button on the medial femoral cortex. The distal end is pulled through the tunnel created in the fibular head and tensioned with the knee in 30° of flexion. Fixation is achieved with a bioabsorbable interference screw placed in the fibular head tunnel. In patients who require combined LCL and popliteofibular ligament reconstruction, the distal end of the popliteofibular graft is brought posterior to anterior through a soft-tissue tun- Figure 8 Lateral approach to a knee dislocation involving injury of the ACL, PCL, and LCL nel created at the insertion of the bi- as well as the posterolateral structures. A, Incisions for combined ACL-PCL-posterolateral ceps femoris tendon. corner injury. B, Lateral exposure for repair of the posterolateral corner and LCL injuries. (Reproduced with permission from Cole BJ, Harner CD: The multiple ligament injured knee. Clin Sports Med 1999;18:241-262.) Rehabilitation

Postoperative rehabilitation is critical iosteally from Gerdy’s tubercle to in- midsubstance injuries using ham- to patient outcome. For the first 6 to crease exposure to the LCL and popli- string autograft or tibialis anterior 8 weeks, the primary goal is to de- teus tendon insertions.All repairs and tendon allograft. A tunnel is created crease swelling and maximize quad- reconstructions are performed with in the proximal fibula. The graft is riceps muscle firing.51 With primary the knee in 30° of flexion. passed deep to the LCL and placed repair, the initial fixation may be ten- Peripheral tears of the lateral me- into a closed-end tunnel at the ana- uous and vulnerable to failure if niscus are repaired with nonabsorbable sutures, and capsular avulsions are fixed with suture anchors. Bony avulsions of the LCL or popliteus tendon are anatomically repaired. Achil- les tendon allograft can be used for LCL reconstruction; a 7- to 8-mm bone block is fixed to the fibular head with a metal interference screw. The Achilles tendon allograft is secured to the lateral femoral epicondyle with suture anchors. The remaining LCL is meticulously dissected to preserve its proximal and distal remnants. These remnants are tensioned and sutured to the Achilles tendon allograft that has been secured to the lateral femoral condyle (Fig. 9). If there is increased posterolateral rotation on the preoperative examination, the popliteus tendon and its various attachments are addressed. Figure 9 Reconstruction of the LCL. A, Calcaneal bone block of the Achilles tendon allograft is secured to the fibular head using an interference screw. The tendinous portion of the Achil- The location of injury determines the les tendon allograft is sutured to the insertion of the native LCL. B, The tendinous portion treatment method; femoral avulsions of the Achilles tendon allograft is oversewn to the native LCL remnant. (Adapted with per- are repaired directly. A popliteofibu- mission from Cole BJ, Harner CD: The multiple ligament injured knee. Clin Sports Med 1999; 18:241-262.) lar reconstruction is performed for

Vol 12, No 5, September/October 2004 343 The Acutely Dislocated Knee: Evaluation and Management

Progression from partial to full weight bearing as tolerated is done over the first 4 weeks unless a lateral repair or reconstruction was performed. In those cases, patients must remain partial weight bearing and locked in extension for 8 weeks to protect the lateral structures. Once patients have regained good quadriceps control (approximately 4 weeks), the brace may be unlocked for controlled gait training. Patients generally require crutches for 6 to 8 weeks depending on ROM, strength, and am- bulatory ability. The brace is usually discontinued at approximately 6 to 8 weeks after 90° to 100° of knee flexion is achieved. Gentle manipulation is required in patients who struggle to regain flexion (<90°) beyond 8 to 12 weeks. Running is permitted at 6 months if 80% of quadriceps strength has been achieved. Return to sports averages between 9 and 12 months. Patients may return to sedentary Figure 10 Lateral (A) and anteroposterior (B) views after reconstruction of the popliteofib- work in approximately 2 weeks and ular ligament. (Adapted with permission from Cole BJ, Harner CD: The multiple ligament injured knee. Clin Sports Med 1999;18:241-262.) to heavy labor in 6 to 9 months.

Results stressed too early. Therefore, the knee ia. Active flexion is avoided for the should remain in a brace locked in full first 6 weeks to prevent posterior tib- Studies that evaluate the results of sur- extension for the first 4 weeks to pro- ial translation resulting from ham- gical management of knee dislocation vide maximum protection. Initial re- string contraction. During this peri- are limited in number and vary in habilitation should focus on restoring od, motion is limited to 90° of flexion. regard to the involved ligamentous full passive extension symmetric to After 6 weeks, passive and active- injuries, surgical technique, graft se- that of the uninjured knee and restor- assisted ROM and stretching exercis- lection, outcomes assessment, and post- ing quadriceps muscle function such es are begun to increase knee flexion. operative rehabilitation.9-12,42 Thus, it that the patient can perform a straight Knee flexion symmetric to that of the is difficult to draw conclusions regard- leg raise without a quadriceps lag. Ex- uninjured knee should be achieved ing the efficacy of surgical treatment. ercises immediately after surgery in- within 12 weeks. Harner et al52 recently reviewed clude passive knee extension (avoid- Quadriceps exercises are pro- the results of the protocol described ing hyperextension in patients with gressed to limited-arc, open-chain above for surgical and postoperative repair or reconstruction of the poster- knee extension exercises as tolerated management of knee dislocation with olateral structures), isometric quad- after 4 weeks. These exercises are per- associated multiple-ligament injury. riceps sets, and straight leg raises. formed only from 75° to 60° of knee Forty-seven consecutive patients who High-intensity electrical stimulation flexion to prevent excessive stress on presented with a spontaneously re- may be used to improve quadriceps the reconstructed grafts. Open kinet- duced or grossly dislocated knee be- function. ic chain knee flexion is avoided for tween 1990 and 1995 were reviewed. Passive ROM is begun 2 to 3 weeks at least 3 months to prevent posteri- Fourteen of these patients were not postoperatively with a physical ther- or tibial translation resulting from included in the study because of con- apist, preventing posterior tibial sub- hamstring contraction. Closed-chain founding variables that altered the luxation during flexion by applying hamstring exercises should be avoid- treatment protocol: four open knee an anterior force to the proximal tib- ed for the first 6 weeks after surgery. dislocations, five vascular injuries,

344 Journal of the American Academy of Orthopaedic Surgeons Jeffrey A. Rihn, MD, et al three patients treated with external ers score. Improved stability was devastating complications, however, ﬁxation, one patient with a severe found in all patients on physical exit is necessary to understand the prin- head injury, and one with a contralat- amination, with more predictable re- ciples of evaluation and management eral, below-the-knee amputation. The sults in the acute group. No statisti- of knee dislocation. Evaluation con- remaining 33 patients underwent cal difference in ROM was evident sists of a brief history, thorough neu- treatment according to the protocol. between patients treated acutely ver- rovascular evaluation, ligamentous ex- Thirty-one of 33 patients were avail- sus chronically. Four patients, all of amination, and radiographic studies. able for evaluation at a mean of 44 whom were treated acutely, required Angiography should be used when- months after surgery. Nineteen pa- manipulation under anesthesia be- ever knee dislocation is suspected to tients underwent surgery <3 weeks cause of postoperative stiffness. evaluate for the presence of a popliteal after the initial injury (acute treat- These results are consistent with artery injury. Initial management in- ment). Twelve patients underwent other reports of surgical management cludes prompt reduction and stabi- surgery ≥3 weeks (average, 6.5 of knee dislocation with allograft re- lization followed by reassessment of months) after the initial injury (chron- construction of the cruciate liga- the neurovascular status of the limb ic treatment). Three of four patients ments.9,11,12,42 The protocol used by and postreduction radiographs. Emer- with injury to the common peroneal Harner et al52 for the treatment of the gent surgery is indicated in patients nerve had transient symptoms that knee with multiple ligament injuries with open dislocation, compartment resolved within 3 months after sur- seems to offer good functional out- syndrome, vascular injury, and irre- gery; one had permanent symptoms come, ROM, and stability for most pa- ducible dislocation. necessitating a tendon transfer 9 tients, particularly those treated with- Deﬁnitive management of the months after surgery. in 3 weeks of initial injury. Most knee with multiple ligament injuries Clinical results were determined patients are able to perform daily ac- remains a controversial topic. Satis- with a questionnaire and physical ex- tivities without difficulty; however, factory results can be achieved with amination. The mean score on the Ac- return to high-demand sports activ- early reconstruction of both the ACL tivities of Daily Living Scale of the ity is less predictable. Patients treat- and PCL using allograft tissue along Knee Outcome Survey was 91 points ed for a chronic injury are more like- with allograft reconstruction of com- for patients with acute treatment and ly to have functional limitations than plete LCL injuries, repair or allograft 84 points for patients with chronic are those treated within 3 weeks of reconstruction of injured posterolat- treatment (P = 0.07).52 Patients in the initial injury. eral structures, and early repair of acute group had a mean Knee Out- complete MCL injuries. Although come Survey Sports Activities Scale technically challenging, adequate score of 89, compared to a mean score Summary knee stability, ROM, and knee func- of 69 in the chronic group (P = 0.04).52 tion can be obtained after anatomic Sixteen of the 19 acutely treated knees Traumatic knee dislocation is relative- repair or reconstruction and appro- and 7 of the 12 chronically treated ly uncommon. Because of the sever- priate postoperative rehabilitation of knees had an excellent or good Mey- ity of this injury and the potential for the dislocated knee.

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346 Journal of the American Academy of Orthopaedic Surgeons