Joint line position restoration during revision total knee replacement.

Forty-five consecutive knee replacement revision operations done in 44 patients with a revision indication of instability were reviewed. In more than 1/2 of these patients, the prosthetic joint line was malpositioned proximally. At surgery, the joint line was restored through the use of distal femoral augments and balancing of the flexion and extension spaces. The fibular styloid and medial epicondylar reference points were used to determine proper position of the joint line. Scarring or laxity of the patellar tendon rendered the use of the Insall-Salvati ratio for determining joint line position inapplicable in these patients having revision knee replacement.