PCL Avulsion of a large posteromedial piece of the tibial plateau
34 year old man with a valgus hyperextension injury to the left knee. Presented to UBC with a painful swollen knee. X-rays showed an avulsion of the posteromedial tibial plateau. We examined the patient under anesthesia to decide how to fix this – his MCL was relatively stable, so we chose a posterior approach. If his MCL was torn completely, we would have used a medial approach to fix the ligament and curl the exposure posteriorly to get at the piece.
Positioning: Prone with tourniquet.
Posterior approach to the knee. The knee crease is just proximal to the knee joint. The crease is marked, then a curved incision is made starting medially proximally, then beginning the gentle curve just distal to the crease, and extending it distally. The key is to find the short saphenous vein distally, which is a fairly large vein. The medial sural cutaneous nerve usually travels with the vein, so this is how you pick it up. Then follow the nerve up proximally to find the tibial nerve in the popliteal fossa. The artery and vein are below it, with the artery technically lying medial to the vein. (Artery-Vein-Nerve in a medial to lateral direction). Once you get down here you will see the superior geniculates come off the artery.
The neurovascular stuff is retracted laterally; watch for little branches of the vein and artery that may tether the bundle medially – these were cauterized. This brings you down to the capsule. The medial head of gastrocs can be gently stripped off the capsule and mobilized medially using the tenotomies and a key elevator. The capsule is then incised. Be ready for the hemarthrosis. The exposure may get you into the knee a bit more proximally than you might expect – we ended up originally in the top part of the intercondylar notch and had to work to get distal enough. The distal exposure is facilitated by stripping the medial gastrocs off the capsule.
Once the capsule was stripped off, the fragment was visualized and secured with two partially threaded cancellous screws. Great case.