Simultaneous management of ipsilateral gonarthritis and extra-articular deformity

Abstract

Background Total knee arthroplasty (TKA) with extra-articular deformity represents a technical challenge to the reconstructive surgeon. Restoration of proper lower limb alignment is crucial to maximize the functional outcome and long-term implant survival. The current study postulates that simultaneous TKA and deformity correction, whether by intra-articular means or by extra-articular osteotomy, can yield favorable outcomes if the correct surgical strategy is used according to the magnitude and location of the pre-existing extra-articular deformity. Patients and methods The study was carried out on 14 consecutive primary total knee replacements in patients with osteoarthritis secondary to extra-articular malunions. The mean preoperative coronal plane deformity was 14.3 ± 5.2° of varus. The mean preoperative mechanical axis deviation was 8.2 ± 2.1 mm medial to the center of the knee and the mean limb-length discrepancy was 1.8 ± 0.7 cm of shortening. The mean time between malunion and TKA was 29 ± 6.1 years. The results were analyzed using the Knee Society clinical and functional scores and the Knee Society radiographic evaluation system. Results At a mean follow-up of 30.4 months, the mean preoperative Knee Society knee score of 49.7 points improved to a mean of 90.4 points at the time of the latest follow-up (P Conclusion Although isolated TKA with intra-articular deformity compensation and ligamentous balancing may be favored in mild to moderate deformities, there may be faster rehabilitation and functional score gain in the short term after surgery. Yet, simultaneous TKA and extra-articular corrective osteotomy has also yielded favorable outcomes and would still remain the technique of choice in severe deformities (>25°), especially with distant deformities from the knee joint line (diaphyseal, metaphyseodiaphyseal). The closer the deformity to the knee joint line, the more it is amenable to intra-articular correction. Careful preoperative planning is necessary to determine which technique would be better in each particular case.