Posteromedial versus direct posterior approach for posterior cruciate ligament avulsion – A comparative study

Abstract

Background/Purpose: Open reduction of acute avulsion of posterior cruciate ligament (PCL) fragment may be achieved through direct posterior approach or posteromedial approach. The aim of our study was to compare these two techniques for fixation of avulsed PCL fragment. Our primary study objective was to study that which of the above techniques provides a better screw placement on post-operative radiographs. The secondary objectives were to study any statistically significant differences in surgical time, blood loss, incidence of neurovascular injury, bone union and functional knee scores in the above two techniques. Materials and methods: This is a prospective, comparative, interventional, single tertiary referral centre-based study from November 2014 to May 2019. Patients in the direct posterior group were treated with the approach described by Abbott and Carpenter, and patients in the posteromedial group were treated with the approach described by Burks and Schaffer. Screw placement was assessed on anteroposterior (AP) and lateral knee X-rays. Blood loss was studied using haemoglobin balance method. Functional scores were recorded preoperatively and at 1-year follow up using Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) knee scores. Results: The posterior group showed better screw placement angle compared to the posteromedial group. In the AP plane, the mean angle of screw placement and fracture line was 83° compared to 59° in the posteromedial group. Average fracture union time, post-operative range of motion and post-operative WOMAC scores were not statistically different in both groups. There were no cases of neurovascular complication, deep vein thrombosis and superficial or deep surgical site infection in any group. Conclusion: Direct posterior approach to PCL avulsion provides better screw placement angle compared to the posteromedial approach, which might result in better interfragmentary compression at the avulsion site. However, the two approaches did not differ statistically in terms of functional scores of patients reported at 1 year.