Analysis of Gait Ability and Patient Reported Outcome Measurements after Robotic-assisted Total Knee Arthroplasty for Osteoarthritis of the Knee with Windswept Deformity

INTRODUCTION: Windswept deformity (WD) refers to valgus deformity in one knee and varus deformity in the other. We performed robotic-assisted (RA) total knee arthroplasty (TKA) for osteoarthritis of the knee with WD, made patient reported outcome measurements (PROMs), and performed gait analysis based on triaxial accelerometery. CASE REPORT: A 76-year-old woman presented to our hospital with bilateral knee pain. Image-free handheld RA TKA was performed on the left knee with severe varus deformity and severe pain during walking. RA TKA was performed on the right knee with severe valgus deformity 1 month later. The RA technique was used to determine implant positioning and the plan for osteotomy intraoperatively, taking into account soft-tissue balance. This made it possible to use a posterior stabilized implant instead of a semi-constrained implant for severe valgus knee deformity with flexion contracture (Krachow classification Type 2). At 1 year after TKA, PROMs were inferior in the knee with pre-operative valgus deformity. Gait ability improved after surgery. Even with the RA technique, it took 8 months to achieve left-right balance while walking and for the variability of the gait cycle to become equivalent to that of a normal knee. CONCLUSION: Primary RA TKA is a viable option for osteoarthritis of the knee with WD. It took time for the gait ability of both knees to become equal and PROMs were better with the varus deformity compared to before surgery.