Modular Femoral Offset Stems Facilitate Joint Line Restoration in Revision Knee Arthroplasty

Restoration of proper joint line position in revision total knee arthroplasty is essential in promoting recovery of function. We retrospectively analyzed joint line restoration and clinical outcomes in 22 consecutive femur revision cases using modular offsets of variable length and direction between the intramedullary fixation rod and the femoral component. Flexion and extension gap balancing techniques and medial epicondylar referencing was used to achieve proper position of the joint line. Position of the reconstructed joint line from postoperative radiographs was compared to the baseline position of intended anatomic placement determined from pre-operative planning radiographs. Postoperative joint line height averaged 1.6 mm distal to baseline (range, 5 mm distal to 2.5 proximal). Joint line was restored to within 2 mm of anatomic position in 12 of the 22 knees. Sixteen patients received conventional, minimally constrained tibial inserts, and joint stability was achieved in all cases.

Level of Evidence: Therapeutic study, Level IV (case series). See Guidelines for Authors for a complete description of levels of evidence.