Review Question - QID 219804

This highly active patient has an isolated displaced bony avulsion of the tibial insertion of the posterior cruciate ligament (PCL). The most appropriate treatment option is open reduction and internal fixation of the avulsed fragment (Answer 4).

Isolated PCL injuries can occur with a direct blow to the proximal tibia with the knee in a flexed position. Clinical exam and advanced imaging assist in the detection of concomitant knee injuries. A dial test is positive if there is greater than 10 degrees of external rotation on the injured limb. A positive dial test at 30 degrees supports an isolated posterolateral corner (PLC) injury, while asymmetry at 30 and 90 degrees supports a combined PLC and PCL injury. Although the PCL is the primary restraint to posterior tibial translation, isolated PCL injuries generally respond well to non-operative management with excellent functional results. Due to the rarity of PCL avulsion fractures, there is not high-quality literature comparing operative to nonoperative management. However, expert opinion and historical evidence of loss of motion with nonoperative treatment supports operative intervention. As such, primary repair of bony avulsion injuries is recommended.

Shelbourne et al. presented 10-year follow-up data on 44 patients treated nonoperatively for an isolated PCL injury. All patients maintained full ROM of the injured knee. The mean quadriceps muscle strength was 97% of the uninjured leg. The prevalence of moderate to severe osteoarthritis was 11%. The authors recommend initial non-operative management for isolated ligamentous PCL injuries.

Hooper et al. performed a systematic review assessing treatment options for tibial-sided PCL avulsion injuries, including 28 articles and 637 patients. Arthroscopic treatment resulted in a higher percentage of International Knee Documentation Committee (IKDC) grade A scores (indicating a normal knee), a higher percentage of return to pre-injury level of activity, and a slightly higher rate of arthrofibrosis compared to open treatment. The authors concluded that both open and arthroscopic approaches yield similar outcomes and complications, with arthroscopic treatment carrying the added benefit of intra-articular evaluation and management of concomitant injuries such as a meniscal tear or loose osteochondral fragment.

Patel et al. published data on 58 isolated PCL injuries that were treated non-operatively. No statistical correlation was seen between initial PCL laxity and functional outcome scores. The authors recommend non-operative management for isolated ligamentous PCL injuries.

Figures A and B are AP and lateral radiographs of a knee with visible avulsion of the tibial PCL insertion. Figure C is a sagittal CT cut demonstrating a displaced avulsion fragment of the proximal tibia at the PCL insertion.

Incorrect Answers:
Answer 1: Immediate therapy is appropriate for isolated ligamentous injuries.
Answer 2: 12 weeks of extension is too long of a treatment course.
Answer 3: Allograft reconstruction is indicated in a functionally unstable knee with concomitant injuries.
Answer 4: A high tibial osteotomy is indicated for chronic PCL insufficiency.