Evaluation of the anatomy of the common peroneal nerve. Defining nerve-at-risk in arthroscopically assisted lateral meniscus repair.

A two-part study was undertaken to clarify the anatomy of the common peroneal nerve at the level of the lateral joint line and risk factors associated with arthroscopically assisted inside-out lateral meniscus repair. In part I, 70 legs in 35 preserved cadavera were dissected to evaluate the relevant anatomy of the common peroneal nerve; 7 (10%) manifested division of the common peroneal nerve into deep and superficial branches proximal to the knee joint. A cutaneous branch not previously described in the literature emanated from the common peroneal trunk in 21 of the legs (30%). In part II, arthroscopically assisted inside-out lateral meniscus repair was performed on 10 fresh-frozen cadaveric knees. Divergence between suture arms increased as suture position was sequentially posterior. Capture of a nerve branch occurred in 2 knees (20%) when posterior retraction was not used. Nerve involvement was eliminated when a retractor was employed. There was significant anatomic variability in the course and branching pattern of the common peroneal nerve at the level of the lateral joint line. During arthroscopically assisted inside-out lateral meniscus repair, risk of injuring the peroneal nerve was related to suture position because of the proximity of anatomic structures and the tendency for suture divergence with soft tissue tethering.