Return to Sport in Middle-aged and Older Athletes After Unicompartmental Knee Arthroplasty at a Mean 10-Year Follow-up: Radiographic and Clinical Outcomes.

BACKGROUND

Return to sport is essential information when an athlete contemplates surgical intervention. Young athletes, <30 years of age, may undergo complex cartilage procedures or femoral/tibial osteotomies to successfully treat single-compartment knee osteoarthritis. Unicompartmental knee arthroplasty (UKA) may offer an attractive alternative option to middle-aged/older athletes with timely return to the same sport without a lengthy rehabilitation.

PURPOSE

The purpose of this study was to determine if athletes are able to return to the same level of vigorous and moderate sports after fixed-bearing intramedullary nonrobotic UKA and the specific sports activities that these athletes continued to participate in at a minimum of 5 years. We hypothesized that UKA in the appropriately selected middle-aged/older athlete would yield high return to sport after UKA with high patient satisfaction. We also hypothesized that UKA would allow athletes to return to their sports of choice.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

We identified 245 patients who underwent a UKA by a single surgeon between 2003 and 2017. Athletes were included if they participated in vigorous or moderate sports, as defined by the American College of Sports Medicine, and had minimum 5-year follow-up. The primary outcome was return to vigorous or moderate sports after UKA. Secondary outcomes included the Knee injury and Osteoarthritis Outcome Score (KOOS) Activities of Daily Living score, KOOS Sport and Recreation score, Lysholm score, Patient Acceptable Symptom State (PASS) analysis, and radiographic analysis.

RESULTS

An overall 169 athletes met the inclusion criteria and were evaluated for return to sports. A total of 98% (165/169) returned to vigorous or moderate sports participation. The mean ± SD time to return to sport was 5.2 ± 2.3 months in the 39- to 50-year-old cohort, 5.8 ± 3.2 months in athletes aged 51 to 64 years, and 5.2 ± 3.0 months in athletes aged ≥65 years. A total of 143 athletes had minimum 5-year clinical and radiographic follow-up (mean, 10 years; range, 5-19 years). Maintenance of vigorous and moderate sport was seen in 99% (142/143) of athletes at a mean 10 years. In athletes who participated in vigorous sports, the mean Lysholm score was 85 ± 17, and 83% reached the PASS for KOOS Sport and Recreation. Radiographic analysis revealed no evidence of implant loosening (ie, subsidence, radiolucency) or osteolysis, and limb alignment and posterior slope of the implant were within normal limits.

CONCLUSION

Athletes returned to sport at a mean 5 months after UKA implantation, with 98% (165/169) participating in vigorous or moderate sports. UKA is recommended as an alternative procedure in middle-aged and older athletes with single-compartment osteoarthritis who are contemplating a return to vigorous or moderate sport.