Fabellar impingement in total knee arthroplasty. A case report.

Fabellar impingement can cause postoperative pain, swelling, and catching, and can significantly compromise the results of total knee arthroplasty. The appearance of a large fabella on preoperative radiographs should raise suspicion about possible impingement. Impingement against the femoral or tibial component of the prosthesis should be assessed by inspection and palpation during trial reduction. The fabella can be removed via the anterior approach prior to component fixation, although it tends to be firmly embedded in the lateral head of the gastrocnemius tendon and requires careful dissection. A separate posterolateral approach will most likely be needed to accomplish complete fabellar excision after the components are secured.