Anatomic and biomechanical aspects of pie crusting posterolateral structures for valgus deformity correction in total knee arthroplasty - A cadavericstudy

Correction of valgus deformity during total knee arthroplasty is usually ca rried out by releasing lateral supporting structures from the femoral side of the joint. A new technique has been advocated that involves multiple sta bs of the scalpel blade or pie crusting of the posterolateral corner. It is the hypothesis of this study that the correction achieved by using this te chnique occurs when the lateral collateral ligament is effectively released and that the common peroneal nerve may be at risk. Using a cadaveric model with 6 knees tested, significant differences were determined between 2 sep arate pie crusting steps as well as between releasing the lateral collatera l ligament and popliteus tendons. Anatomic dissection studies also showed t hat in full extension the peroneal nerve may be less than the depth of a nu mber 11 blade (16 mm) from the posterolateral corner, and the nerve may be at risk during this technique. These results show that major deformity corr ection obtained using the pie crusting technique is probably through effect ive release of the lateral collateral ligament.