Outcomes and survivorship of unicondylar knee arthroplasty in patients with severe deformity.

Abstract

Fifty-three patients with severe deformity (40 patients with FFD ≥15° and 13 patients with varus deformity ≥15°, Group A) were matched with 53 patients with less severe deformities who underwent UKA (Group B/controls) in terms of age, sex, BMI and duration of follow-up. Their flexion range, Knee Society scores (KSS), Oxford knee scores (OKS) and SF-36 QOL scores were analysed pre-operatively and at 2years. Group A patients were largely similar to Group B patients pre-operatively in terms of maximum flexion angle, OKS and SF-36 scores except for knee score and mental health component of SF-36. At 2years, Group A reported largely similar results compared with Group B in all outcome scores (OKS, KSS, SF-36) and flexion angle. Post-operative mechanical alignment was better for the control group though it is not statistically significant. There were no revisions in the patients with severe pre-operative deformity at 5years post-operatively. (Survivorship 100% at 5years). Selected patients with severe deformity can achieve good function and QOL with UKA if satisfactory mechanical alignment is restored. This study supports a broadening of the indications of UKA; however, further follow-up is needed to assess the longer-term durability of the operation. IV.