Adolescent Knee Pain Management Gregory A

FEATURE

Adolescent Knee Pain Management Gregory A. Schmale, MD

he child or adolescent who referred to a pediatric and adolescent presents with a painful knee sports medicine specialist. T is a routine challenge for most Injuries to the knee occurred with primary care providers. Knee pain is an incidence of nearly one per player one of the most common reasons for per year in a survey of English teen- referral from our local primary care age soccer players,1 and the prevalence providers to the orthopedic and sports of diffuse anterior knee pain has been medicine specialist. Complaints may reported in up to 40% of adolescents be acute or long-standing, and making participating in sports.2 Common acute a diagnosis that responds to treatment knee injuries and chronic knee condi- for the patient with long-standing knee tions that present in youth can be found pain may be elusive. Careful consid- in Table 1 (see page 123) eration of the history, physical exam findings, and imaging study results can IMPORTANCE OF help sort through which patients can HISTORY IN MEDICAL EXAM be managed in the primary care pro- Complaints of knee pain are typi- vider’s office and which ones should be cally either acute or chronic. A patient with a recent injury may be particularly

Gregory A. Schmale, MD, is Director, Orthope- difficult to work-up: the history of the dic Medical Education and Local Program Direc- event may be fresh in the patient’s mind tor, Orthopedics Residency at Seattle Children’s and the pain that resulted may still lin- Hospital; and Associate Professor, Department ger, leading to a nervous, tense, and of Orthopaedics and Sports Medicine, University difficult-to-examine patient, depending of Washington School of Medicine. on the level of their discomfort. Address correspondence to: Gregory A. A history of swelling suggests inju- Schmale, MD, Department of Orthopedics and Sports Medicine, 4800 Sand Point Way NE, Se- ry within the joint. In the acute setting, attle, WA 98105; email: Gregory.schmale@seattle- swelling likely represents a hemarthro- childrens.org. sis, or blood in the joint from trauma. Disclosure: The author has no relevant finan- An anterior cruciate ligament (ACL) cial relationships to disclose. tear, physeal or osteochondral fracture, doi: 10.3928/00904481-20130222-12 patella dislocation, or meniscus tear © Shutterstock

122 | Healio.com/Pediatrics PEDIATRIC ANNALS 42:3 | MARCH 2013 FEATURE can all produce a hemarthrosis.3,4 In TABLE 1. patients with chronic swelling, the effusion may be indicative of an inflam- Common Causes of Knee Pain in Youth matory arthritis. Acute Injuries Semi-Acute Conditions Chronic Conditions Most people have joints that “pop,” Fracture (femur/tibia/patella) Osteochondritis dissecans Inflammatory arthritis likely reflecting soft tissues snapping Dislocation (patella) Slipped capital femoral Apophysitis: benignly over bony prominences. The epiphysis Osgood-Schlatter “cracking of knuckles” type of joint pop- Sinding-Larsen-Johansson ping is believed to be a benign process, resulting from a cavitation phenomenon Meniscus tear (torn discoid Loose body Anterior knee pain: meniscus) Patello-femoral syndrome where sudden volumetric changes in the Impinging Hoffa’s fat pad joint space are accompanied by popping Anterior cruciate ligament Tumor Tendonitis: as carbon dioxide moves out of solu- (ACL) tear Quadriceps 5 tion from the dissolved state. Joints Patellar tendon that “clunk” or “snap,” with a jump of Medial collateral ligament Infection the patella or the tibia during knee flex- (MCL) tear ion or extension, suggest a mechanical Soft tissue contusion problem (see Table 2, page 124). Joints that lock or catch suggest a meniscal pathology or a loose body in the knee. The notion of “giving way” is establishes a baseline for comparison coloration can be done without touch- a difficult symptom to interpret. Quad- and can potentially reassure the patient ing the injured knee. Gently palpating riceps inhibition, or the cessation of of the examiner’s gentle approach. On the joint line and the physes, the tibial quadriceps contraction when a patient the other hand, starting on the unin- tubercle and the inferior border of the experiences pain can produce “giv- jured side with an aggressive, forceful, patella helps identify the location and ing way”; so too does a subluxating and rapid exam may only heighten the normal prominences of these land- or dislocating patella, or a knee with patient’s apprehension. A complaint of marks. Flexing the knee somewhat may major ligament injury. Distinguishing knee pain may reflect irritation of the help the examiner locate the joint line, between these different causes can be obturator nerve from a hip pathology, as it lies both medial and lateral to the difficult. Recreating the apprehensive so examination of the hips should be in- inferior border of the patella when the feeling in the patient during the exam cluded when the patient is supine. Log knee is flexed. Tests of stability (de- by using specific maneuvers can help rolling the limb on the unaffected side, scribed below), and gentle provocation confirm a diagnosis. followed by gentle hip flexion to 90 de- of the uninjured knee will give the ex- grees, then internal and external rotation aminer a sense of baseline tightness or STAGES OF FULL of the hip in flexion will establish the laxity of the knee. PHYSICAL EXAM norm for comparison. On the injured On the injured side, gently palpat- For patients who are uncomfort- side, pain with log rolling while holding ing the landmarks described above may able and/or apprehensive, I recommend the knee still may suggest a hip pathol- help establish the point of maximal limiting the exam of the injured knee. ogy. If flexing the hip results in obligate tenderness (PMT), though patient dis- However, I do try to gain as much in- external rotation and abduction, that comfort may make identification of the formation as possible from the visit. suggests hip pathology such as slipped PMT impossible. The PMT is a valu- Are there crutches in the room? Even capital femoral epiphysis (SCFE). able landmark in identifying the site if there are crutches present, I’ll ask the of injury or pathology in the child and patient to try to take a few steps without LIMITED EXAM OF THE adolescent’s knee.6 Mild flexion, if tol- them, if they think they can. Watching ACUTELY INJURED KNEE erated, followed by stability testing can the patient walk may help in identifica- After examining the hips, the unin- be useful. However, I am quick to wrap- tion of the source of their discomfort, jured knee is observed palpated, gen- up the exam of the acutely injured knee potentially suggesting hip as opposed to tly ranged, and provoked to establish a and order orthogonal radiographs (AP knee pathology. baseline. Comparing the two knees with and lateral, supine) if there is marked Examining the uninjured side first regards to size, resting position, and swelling, ecchymosis, gross instability,

PEDIATRIC ANNALS 42:3 | MARCH 2013 Healio.com/Pediatrics | 123 FEATURE or refusal to ambulate. Worth noting, the TABLE 2. Ottawa knee rules have been validated in children, having a 100% sensitivity for Common symptoms and signs of various acute knee injuries identification of fracture in patients ages 2 to 16 years. The Ottawa criteria for ra- Injury Symptoms Signs diographs of the acutely injured knee in- Soft tissue Diffuse pain Local swelling without effusion clude: 1) tenderness at head of fibula; 2) contusion Painful walking Resolving ecchymosis isolated tenderness of patella (no bone Bruising tenderness of knee other than patella); ACL/MCL sprain Wobbly knee — instability Unstable ligament exam 3) inability to flex to 90 degrees; and 4) Swelling after activity Palpable effusion inability to bear weight immediately and Meniscus tear Sudden onset loss of motion in the emergency department (defined as Intermittent clunking or snapping an inability to transfer weight twice onto each lower limb, regardless of limping).7 Patellar Weakness Tender medial knee dislocation Intermittent “giving way” Apprehension with lateral push to Prescribing a hinged knee brace that patella when gently flexing from is left open enough to allow a tolerable full extension range of motion and crutches as needed Loose body Intermittent locking or pinching Palpable mobile body for comfort, along with the encourage- Feels like something may be loose Variable range of motion ment to remove the brace and gently and “floating” around in the joint move the knee when resting is often the Fracture Inability to weight bear Ecchymosis best approach to the patient with a pain- Physeal tenderness ful and acutely injured knee. Rest, ice, Tibial tubercle tenderness compression, and elevation (RICE) is a ACL = anterior cruciate ligament; MCL = medial collateral ligament. good rule of thumb. Acetaminophen or nonsteroidal anti-inflammatory medica- tions may help with pain relief. The patient can then be re-examined in about a flexion will help determine any anterior palpably greater than the uninjured side week’s time. instability. If present, this suggests a tear with a soft end-point would suggest a of the ACL. tear of the PCL. An anterior drawer test COMPLETE EXAM OF THE KNEE An effective Lachman’s exam re- at 90 degrees of knee flexion may test Again, an approach that works well quires a relaxed patient, so performing the integrity of the ACL, although the for the order of the complete knee exam this, with a gentle touch, prior to any ACL is under greatest tension at only 20 includes observing gait, examining other manipulation or palpation increas- degrees of knee flexion. Therefore, there hips, followed by the knee examination, es the chances the patient will be relaxed is a greater sensitivity for ACL deficien- focusing on the uninjured side before during the maneuver. Laxity on Lach- cy with Lachman’s exam than there is going to the side of complaint. Observ- man’s testing suggests an ACL injury. A with the anterior drawer test. ing, palpating gently, ranging, then per- pivot shift test typically is not possible in forming tests for knee stability followed the acutely injured patient, as full exten- Varus and Valgus Testing by provocative tests is the typical rec- sion and relaxation are prerequisites to Stability testing in full extension and ommended order to proceed through the a successful test. When full knee exten- mild flexion can give information on exam, though I like to do my basic tests sion is possible, the pivot shift can reveal capsular integrity as well as integrity of stability before looking for a point rotatory instability, as the lateral femo- of the collateral ligaments; pain with of maximal tenderness, so the patient is ral condyle may flick past the iliotibial either maneuver may suggest meniscal most relaxed for stability testing. band, also indicative of an ACL tear. injury as well. As the medial meniscus While the patient is supine with the has attachments to the MCL, valgus Tests of Stability knee flexed to 90 degrees and the pa- stress may result in medial pain from Lachman’s Testing tient’s heel on the table, posterior di- movement of a torn medial meniscus Once the knee has been evaluated for rected pressure or a posterior drawer when the MCL comes under tension, swelling and patella dislocation, a Lach- test can reveal a posterior cruciate liga- whereas lateral pain may reflect pinch- man’s test in about 20 degrees of knee ment (PCL) deficiency. Excursion that is ing of a torn lateral meniscus. Medial-

124 | Healio.com/Pediatrics PEDIATRIC ANNALS 42:3 | MARCH 2013 FEATURE sided pain with varus stressing may be can be difficult, particularly when there symptoms, persistent effusions, and related to pinching of a torn medial me- is an effusion or hemarthrosis. Palpating gross instability, ordering an MRI for niscus. For skeletally immature patients, the inferior border of the patella with the acute or chronic knee complaints is gen- tenderness along the condyles 2 cm to knee mildly flexed, followed by sliding erally not advised. Most pediatric ortho- 3 cm from the joint line may suggest a the examiner’s fingers off to either side pedic specialists prefer to first examine physeal fracture. may help establish the location of the the patient before an MRI is ordered. Gently grasping both of the patient’s joint lines. Exam by the primary care practitioner heels and lifting the feet off the table will The distal femoral physis lies at the has been shown to be quite sensitive for help indicate the magnitude of the loss level of the medial and lateral femoral ACL tears,10 and obtaining repeat MRI of knee flexion of the injured limb. Avoid epicondyles, whereas on the tibia the prior to surgery for knee injuries (for looking for the maximum tolerable knee improved study quality or a more timely flexion until later in the examination. study) occurs commonly, suggesting the While flexing the knee gently, pay Exam by the primary care disutility of the original MRI studies.11 careful attention to the patient’s de- practitioner has been meanor to determine at what point flex- REFERRALS TO SPECIALISTS ion becomes a bit uncomfortable. Ask shown to be quite sensitive The patient with persistent swelling where it hurts when this point is reached for ACL tears. and mechanical symptoms typically has to determine if the pain is anterior, sug- an ACL deficiency, medial or lateral in- gesting anterior injury or tightness, or stability, fracture, meniscal tear, or pa- posterior, suggesting posterior injury proximal physis extends from about 1 tellar instability. Although patients with such as a torn meniscus. cm to 2 cm inferior to the joint line me- small meniscal tears and early patellar dially and laterally to just below to the instability may respond to a physical Palpitation for Effusion tibial tubercle anteriorly. therapy program, MCL and PCL insta- Follow the Lachman’s test with what bility and nondisplaced physeal frac- might be described as thorough palpa- Meniscus Pathology tures may be treated with a period of tion — look for the PMT. Identifying With fingers on the joint line and a bracing followed by a guided rehabili- the PMT is key to determining the pa- hand on the patient’s foot and ankle, rotation program; whereas untreated ACL thology6: joint line tenderness suggests tate the ankle while flexing the knee and tears may lead to further giving-way, meniscus injury, tenderness along the place gentle varus pressure on the knee, risking articular cartilage or meniscal course of the medial collateral ligament then gently repeat the process with a injury. Patients with ACL tears should (MCL) suggests MCL sprain, tenderness rotation in the opposite direction while be referred to an orthopedist. along the medial border of the patella or placing upon it a gentle valgus stress. If adductor tubercle suggests a patella dis- during these maneuvers the patient expe- Hoffa’s Fat Pad location, and tenderness on either femo- riences any pain, or if there is a clicking In those patients who have a history ral condyle in full knee flexion may sug- or clunking sound, or if there is a palpable of having fallen directly on their knee, gest osteochondral fracture. Tenderness flipping of tissues under the examiner’s or having been struck on the front of at the inferior border of the patella or fingers, a meniscal pathology is likely.8 their knee during a collision in sport tibial tubercle suggests an apophysitis Pain while bearing weight on the affected may develop anterior scar tissue that can or inflammation of a growth center at limb, with the knee flexed 20 degrees produce painful pinching with full knee the attachment of a tendon (Sinding- while twisting back and forth is an even extension. This is known as an imping- Larsen-Johansson and Osgood-Schlat- more sensitive test for meniscus tear.9 ing Hoffa’s fat pad — the exuberant tis- ter, respectively). An effusion may be Obtaining biplanar orthogonal radio- sue that grew in response to the anterior detected by milking the suprapatellar graphs can be useful, as fractures and injury may cause the fat pad to be adher- pouch from proximal to distal, looking patellar subluxation may both be evident ent to the ACL, and with knee extension, for fluid accumulation medial and lat- (see the discussion above under Limit- may cause a posterior pulling of this ex- eral to the patella. If posterior pressure ed Exam of the Acutely Injured Knee); cessive tissue and fat pad into the knee on the patella (ballotment) produces a however, unless clinical suspicion is joint. Patients with this condition often medial and lateral fluid wave, that sug- high, such as with isolated joint line complain of discomfort when the knee gests fluid in the joint. tenderness that is unresponsive to ther- is fully extended, made worse when the At times, indentifying the joint line apy, pain with provocation, loose body examiner applies pressure anteriorly at

PEDIATRIC ANNALS 42:3 | MARCH 2013 Healio.com/Pediatrics | 125 FEATURE either the medial or lateral joint lines, inflammatory and referral to a pediatric cation events, usually with a history of adjacent to the patellar tendon.12 rheumatologist would then be recom- a substantial initial trauma. Over time, Aggressive massage in the area of mended. as dislocations become more frequent, discomfort may stretch the underlying The patient with SCFEs or other hip the patella may slip out — partially or tissues and provide relief over time. Ar- pathology may complain of medial knee completely — with less trauma, less of throscopic treatment of impinging tissue or thigh pain, walk with a turned out a twist, less drama with each event. On often brings relief, although recurrence foot, resist flexion, and display obligate exam, a patient with patellar instability of symptoms, likely due to the return of abduction and external rotation when the will typically flinch or show apprehen- scar tissue within the joint capsule, may hip is flexed. Painful internal rotation is sion when laterally directed pressure is occur. Massage, stretching of anterior also a classic exam finding. applied to the patella while the knee is and posterior thigh musculature, and The anterior and “frog leg” pelvis ra- gently flexed. strengthening of core and hip abductors diograph should confirm a diagnosis of are the initial treatments of choice for SCFE. As the capital femoral epiphysis BENIGN ANTERIOR KNEE PAIN this diagnosis. slips, it typically occurs in a slow yet ir- The most common, and perhaps reversible fashion. Treatment includes most challenging, variety of knee pain Osteochondritis Dissecans halting the slipping with a surgery to fix in the older child and adolescent is be- Tenderness directly over a femoral the capital femoral physis on the neck nign anterior knee pain. Patients tend to condyle with full flexion of the knee where it lies, or “in-situ” fixation. The wave their hand over their knee when may suggest osteochondritis dissecans, greater the slip, the more compromised pointing to their site of greatest pain. It a diagnosis that may be confirmed with the function of the limb, so early treat- is often bilateral, but can be unilateral, radiographs of the knee.13 This diagnosis ment may prevent a poor result. A fall perhaps brought on by a contusion to may benefit from an early MRI, as fluid in a patient who is walking on their the knee through a collision. Patients deep to the lesion may suggest poor like- slipped capital femoral epiphysis may might describe pain that follows activ- lihood of resolution or healing with rest. lead to what is known as a “stable slip” ity, sometimes even pain that prevents becoming and “unstable slip”, with a further play, although swelling is rarely ‘Bad Actors’ much higher likelihood of a poor out- seen. Mechanical symptoms are also For patients with a chronically pain- come. Sending the patient to the local rare. They might also note pain that ful knee or a knee with the insidious on- emergency department in a wheelchair occurs after sitting for prolonged pe- set of pain, keep in mind potential “bad is the important next step in treatment of riods of time, pain when ascending or actors” such as a tumor near the knee, a SCFE.14 descending stairs, and tenderness over inflammatory arthritis, hip pathology the tibial tubercle, inferior border of the such as SCFE or an infection. Patellofemoral Joint Pain patella, or the medial or lateral borders If the PMT is over the distal thigh or Pain associated with abnormal load- of the patella. upper leg, or if there is a stiff knee, night ing at the patellofemoral joint is also Anterior knee pain is often exacer- pain, loss of energy and/or appetite, and common.15 Increased discomfort with bated by tight quadriceps muscles (indi- any enlarged local lymph nodes, then a posterior-directed pressure or a lat- cated if the patient is unable to tolerate there is the possibility of neoplasia or in- eral tilt of the patella during knee flex- a hurdler’s stretch) and tight hamstrings fection. Radiographs and serum inflam- ion may exacerbate symptoms. A wide (popliteal angles > 30 degrees to 40 de- matory markers may help point toward pelvis or marked j-tracking of the patella grees) through an increase in pressure at such a diagnosis. may suggest increased lateral pressure at the patellofemoral joint, as the patella The pain-free swollen knee, worse the patellofemoral joint, which also may is caught within a tight extensor mech- with activity and accompanied by morn- be painful. anism, whereas the tight quadriceps ing stiffness, should suggest the possi- Strengthening the vastus medialis, strain against the opposition of tight bility of juvenile idiopathic arthritis. the medial quadriceps, and the anterior hamstrings.16 Hamstring and quadriceps Elevated serum inflammatory markers thigh muscles may help reduce this lat- stretching is the optimal treatment for and elevated anti-nuclear antibody titers eral patellar pressure, resulting in re- this type of anterior knee pain. These would support such a diagnosis. A knee duced pain during activity. When knee stretches can be done at home; guidance aspiration would reveal many white pain is associated with patellar instabili- from a physical therapist may help keep cells (> 1,000/mm3) with no growth on ty, the patient may present with a history a patient on track in their quest to regain culture. A trial of a nonsteroidal anti- of “giving way” or frank patellar dislo- better flexibility.

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CASES OF APOPHYSITIS benefit from an aggressive stretching accuracy of a new clinical test (the Thessaly For cases of apophysitis (Osgood- and strengthening program, keeping in test) for early detection of meniscal tears. J Bone Joint Surg Am. 2005;87(5):955-962. Schlatter at the tibial tubercle, Sinding- mind the possibility of a hip or thigh 10. Wagemakers HP, Luijsterburg PA, Boks SS, Larson-Johansson at the inferior border pathology presenting as a knee com- et al. Diagnostic accuracy of history taking of the patella), where cartilage growth plaint. Obtain orthogonal radiographs and physical examination for assessing anterior cruciate ligament lesions of the knee centers may fail under tension, again, before any other imaging study, and in primary care. Arch Phys Med Rehab. tight quadriceps and hamstring muscles consider referring to specialists before 2010;91(9):1452-1459. are often seen. Neither radiographs nor ordering MRIs. 11. Rath PA, Gugala Z, Lindsey RW, Efficacy of repeat magnetic resonance imaging of the MRI are useful in making the diagno- knee. Orthopedics. 2011;34(11):e703-707. sis, except to rule out other patholo- REFERENCES 12. Dragoo JL, Johnson C, McConnell J. Evalua- gies. Daily stretching over a matter of 1. Moore O, Cloke DJ, Avery PJ, Beasley I, tion and treatment of disorders of the infrapa- Deehan DJ. English Premier Academy knee months is the preferred treatment for tellar fat pad. Sports Med. 2012;42(1):51-67. injuries: lessons from a 5 year study. J Sports 13. Kocher MS, Micheli LJ, Yaniv M, Zurakows- this condition. Sci. 2011;29(14):1535-1544. ki D, Ames A, Adrignolo AA. Functional and This is a frustrating diagnosis for 2. Galanty HL, Matthews C, Hergenroeder AC. radiographic outcome of juvenile osteochon- parents to manage because there are no Anterior knee pain in adolescents. Clin J dritis dissecans of the knee treated with tran- Sports Med. 1994;4:176-181. sarticular arthroscopic drilling. Am J Sports tests of confirmation, only exam find- 3. Stanitski C, Harvell JC, Fu F. Observa- Med. 2001;29(5):562-566. ings to support it; and there is no treat- tions on acute knee hemarthrosis in chil- 14. Loder RT. Slipped capital femoral epiphysis. ment that will cure it, only behaviors dren and adolescents. J Pediatr Orthop. Am Fam Physician. 1998;57(9):2135-2142. 1993;13(4):506-510. 15. Heng RC, Haw CS. Patello-femoral pain and exercises that will slowly reduce it. 4. Eiskjaer S, Larsen ST, Schmidt MB. The syndrome. Curr Orthopaed. 1996;10:256- It does not respond well to narcotics, to significance of hemarthrosis of the knee 266. surgery, or even to intermittent physi- in children. Arch Orthop Trauma Surg. 16. Patil S, White L, Jones A, Hui AC. Idiopathic 1988;107(2):96-98. cal therapy. anterior knee pain in the young. A prospec- 5. Brodeur R. The audible release associated tive controlled trial. Acta Orthop Belg. Heat before activity, followed by with joint manipulation. J Manip Physiol 2010;76(3):356-359. slow gentle stretching, then play, and Ther. 1995;18(3):155-164. ice at the conclusion may decrease 6. Staheli LT. Practice of Pediatric Orthope- dics. Philadelphia: Lippincott Williams & symptoms, but does little to treat the Wilkins; 2011. cause. A regular dedicated program of 7. Bullock B, Neto G, Plint A, et al. Valida- daily prolonged stretching is the best tion of the Ottawa knee rule in children: a multicenter study. Ann Emerg Med. treatment. After many months, the an- 2003;42(1):48-55. terior knee pain should subside. 8. Fowler PJ, Lubliner JA. The predictive value of five clinical signs in the evalua- tion of meniscal pathology. Arthroscopy. CONCLUSION 1989;5(3):184-186. Separating acute injuries from 9. Karachalios T, Hantes M, Zibis AH, Zachos chronic conditions may be helpful in V, Karantanas AH, Malizos KN. Diagnostic making the diagnosis of knee pain in an adolescent. Mechanical symptoms and signs are key features of the history and AD INDEX exam, as patients with persistent or re- current painful swelling, and mechani- PFIZER INC cal symptoms such as locking, painful 235 East 42nd Street, New York, NY 10017 Children’s Advil...... C4 popping, catching, or “giving way” SANOFI PASTEUR may have a cartilage injury or ligament Discovery Drive, Swiftwater, PA 18370 tear that would benefit from referral to Sklice...... C2,85,86 an orthopedist. SLACK INCORPORATED Identifying a point of maximum 6900 Grove Road, Thorofare, NJ 08086 tenderness is especially important in Healio.com/Pediatrics...... 121 Infectious Diseases in Children® Education Lab...... C3 diagnosing the adolescent knee, as it so often lies at the site of pathology. In the absence of any point tenderness, While every precaution is taken to ensure accuracy, Pediatric Annals cannot guarantee against occasional changes or omissions in the preparation of this index. consider a process at the knee that may

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