Outcomes after knee arthroplasty in extra-articular deformity.

PURPOSE: To assess functional outcomes in patients undergoing total knee arthroplasty (TKA) without previous corrective osteotomy for treatment of knee osteoarthritis associated with extra-articular deformity.

METHODS: From January to December 2016, patients with knee osteoarthritis with extra-articular deformities who presented for preoperative assessment before TKA were evaluated prospectively. Physical and radiological characteristics were documented pre- and postoperatively.

RESULTS: TKA was performed in 33 knees; 25 were considered for analysis. The mean age was 65.2 years (range, 48-79 years). Sixteen deformities were secondary to fractures and nine to failed osteotomies. The mean Knee Society Score (KSS) improved from 27.1 pre-operatively to 68.7 post-operatively (p = 0.000). Pre-operative mechanical axis ranged from 32° varus (negative) to 26° valgus. After correction, 20 knees were within 3° (varus or valgus) of mechanical alignment.

CONCLUSION: In patients with extra-articular deformities, TKA with asymmetric intra-articular resection and ligament balancing can relieve pain and realign the mechanical axis of the lower limb.