Outcomes after knee arthroplasty in extra-articular deformity

Abstract

Objective: 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.