Usually, Selectively, or Rarely Resurfacing the Patella During Primary Total Knee Arthroplasty: Determining the Best Strategy.

BACKGROUND

Surgeons may "usually" resurface the patella during total knee arthroplasty (TKA), "rarely" resurface, or "selectively" resurface on the basis of certain criteria. It is unknown which of these 3 strategies yields superior outcomes. Utilizing New Zealand Joint Registry data, we investigated (1) what proportion of surgeons employs each of the 3 patellar resurfacing strategies, (2) which strategy is associated with the lowest overall revision rate, and (3) which strategy is associated with the highest 6-month and 5-year Oxford Knee Score (OKS).

METHODS

Two hundred and three surgeons who performed a total of 57,766 primary TKAs from 1999 to 2015 were categorized into the 3 surgeon strategies on the basis of how often they resurfaced the patella during primary total knee arthroplasty; with "rarely" defined as <10% of the time, "selectively" as ≥10% to ≤90%, and "usually" as >90%. For each strategy, the cumulative incidence of all-cause revision was calculated and utilized to construct Kaplan-Meier survival curves. The mean 6-month and 5-year postoperative OKS for each group were utilized for comparison.

RESULTS

Overall, 57% of surgeons selectively resurfaced, 37% rarely resurfaced, and 7% usually resurfaced. The usually resurfacing group was associated with the highest mean OKS at both 6 months (38.57; p < 0.001) and 5 years postoperatively (41.34; p = 0.029), followed by the selectively resurfacing group (6-month OKS, 37.79; 5-year OKS, 40.87) and the rarely resurfacing group (6-month OKS, 36.92; 5-year OKS, 40.02). Overall, there was no difference in the revision rate per 100 component years among the rarely (0.46), selectively (0.52), or usually (0.46) resurfacing groups (p = 0.587). Posterior-stabilized TKAs that were performed by surgeons who selectively resurfaced had a lower revision rate (0.54) than those by surgeons who usually resurfaced (0.64) or rarely resurfaced (0.74; p < 0.001).

CONCLUSIONS

Usually resurfacing the patella was associated with improved patient-reported outcomes, but there was no difference in overall revision rates among the 3 strategies.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.