Posterior drawer after olecranization of the patella in posterior cruciate-injured knees: A cadaver study

Abstract

IntroductionOlecranization of the patella (OP) is a surgical technique that anchors the patella to the tibia using a Steinmann pin to reduce the posterior drawer in cases of acute posterior cruciate ligament (PCL) tears. The advantage of this procedure is that rehabilitation can start early with passive and active mobilization, all the while maintaining the reduced position. The primary objective of this cadaver study was to evaluate the reduction in the posterior drawer induced by OP. The hypothesis was that OP significantly reduces the posterior drawer at 0°, 45° and 90° flexion after isolated PCL transection. Material and methodsA Steinman pin was inserted in 70° flexion on seven fresh cadaver knees. Changes in the posterior drawer were measured on radiographs at 0°, 45° and 90° flexion before and after adding a posterior load (150N) in the following sequence: intact knee, after PCL transection, after OP. Posterior translation was measured in millimetres. ResultsIn unloaded knees, the posterior drawer was significantly reduced after OP in 45° flexion (4.1mm to−1.2mm, p<0.05) and 90° flexion (7.9mm to 3.8mm, p<0.05). When a posterior load was applied, the posterior drawer was significantly reduced in 0° flexion (4.9mm to 0.2mm, p<0.05), 45° flexion (6.7mm to 0.6mm, p<0.05) and 90° flexion (11.8mm to 7.6mm, p<0.05). DiscussionAnchoring the patella to the tibia in 70° flexion led to a significant reduction in the posterior drawer after PCL transection in cadaver knees. Olecranization of the patella may help optimize the healing of an injured PCL treated conservatively. Level of evidenceIII, controlled laboratory study.