A 23-year-old woman presents with left knee pain after falling while skiing. She has mild weight-bearing pain, and her knee feels unstable. On exam, she has full passive and active range of motion and no effusion. She has grade II laxity with valgus stress to the knee. She has no instability with varus stress or with Lachman test. She has no tenderness over the medial or lateral joint line. She is able to straight leg raise against resistance. Anteroposterior and lateral radiographs are shown in Figures 1 and 2.
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The patient has obvious valgus instability to the knee consistent with an MCL sprain. Her radiographs show no evidence of a fracture, which would limit her weight bearing during treatment. She has no effusion or joint line tenderness that would indicate a possible meniscal tear or other intra-articular pathology. MRI is often ordered if associated injuries are suspected, but based on her clinical exam she appears to have an isolated MCL injury. For this reason an MRI is not necessary. An MCL tear can be diagnosed on clinical exam alone. The patient should be treated with a hinged knee brace with weight bearing as tolerated.1,2
The MCL has an abundant blood supply that allows the torn tendon ends to heal together. Treatment with a hinged knee brace protects the knee from further valgus stress while allowing for knee motion. Early knee motion in a hinged knee brace helps enhance healing and improve biomechanical properties of the tendon. Weight bearing in a hinged knee brace does not stress the MCL and should be encouraged early. A typical rehab protocol includes a hinged knee brace with physical therapy for continued strengthening of the knee. The brace is usually worn for 3 to 4 weeks for grade I injuries and 6 weeks for grade II and III injuries. A brace is used until the patient is able to perform activities without pain or instability. The MCL is also tested with valgus stress, and any persistent laxity should be braced and followed closely before the brace is removed.1,2
Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor-in-chief of the Journal of Orthopedics for Physician Assistants (JOPA).
- Wijdicks CA, Griffith CJ, Johansen S, Engebretsen L, Laprade RF. Injuries to the medial collateral ligament and associated medial structures of the knee. J Bone Joint Surg Am. 2010;92:1266-1280.
- Miyamoto RG, Bosco JA, Sherman OH. Treatment of medial collateral ligament injuries. J Am Acad Orthop Surg. 2009;17:152-161.