Make the Diagnosis: Knee Ligaments and Menisci
Prior Probability for a Ligamentous or Meniscal Tear
The physical examination can help in determining which patients are likely to have meniscal or ligamentous injuries of the knee. However, no data exist that allow us to establish reliable prior probability estimates. Among patients with knee pain referred by primary care providers or rheumatologists to an orthopedist, the orthopedist will clinically diagnose meniscal tears in about 25% of patients and ligamentous injuries in about 10%.2 We do not know the underlying distribution of these conditions in patients who do not require referral. Because the mechanism of an injury predicts the actual anatomic defect, experts probably can predict (better than chance) the most likely injury when they either observe the trauma or get a reliable medical history.
Population for Whom Ligamentous or Meniscal Injuries of the Knee Should Be Considered
Adults with knee pain associated with an injury or with mechanical symptoms, including clicking, catching, locking, or giving way.
Detecting the Likelihood of a Ligamentous or Meniscal Injury of the Knee
The best physical examination maneuvers for ligamentous tears or meniscal injuries are shown in Table 27-6. A JAMAInteractive displays the anatomy and some of the maneuvers described in Table 27-6 (http://jama.ama-assn.org/cgi/content/full/286/13/1610/DC1; accessed June 1, 2008).
Table 27-6.Physical Examination Maneuvers for Ligamentous and Meniscal Injuries of the Knee ||Download (.pdf) Table 27-6. Physical Examination Maneuvers for Ligamentous and Meniscal Injuries of the Knee
|Symptom (No. of Studies) ||LR+ (95% CI) ||LR– (95% CI) |
|Anterior Cruciate Ligament Injuries |
|Lachman test (1) ||42 (2.7-651) ||0.1 (0.0-0.4) |
|Anterior drawer test (3) ||3.8 (0.65-22) ||0.3 (0.05-1.5) |
|Meniscal Injuries |
|Joint effusion (1) ||5.7 (0.4-86) ||0.7 (0.5-0.9) |
|Medial lateral grind test (1) ||4.8 (0.8-30) ||0.4 (0.2-0.6) |
|McMurray test (3) ||1.3 (0.9-1.7) ||0.8 (0.6-1.1) |
|Joint line tenderness (2) ||0.9 (0.8-1.0) ||1.1 (1.0-1.3) |
Serial clinical examinations performed by a specialist are a pragmatic reference standard.
MRI is used to rule in or rule out ligamentous tears. Arthroscopy may be required to rule out meniscal tears.
Original Article: Does This Patient Have a Torn Meniscus or Ligament of the Knee?
A 20-year-old man presents to your office complaining of knee pain after playing basketball. During the game, as he came down after jumping for a rebound, another player fell on the back of his calf. He remembers hearing a pop and had pain on standing, preventing him from playing in the remainder of the game. While on the bench, he noticed that ...