Safety and Efficacy of 6.2 mm Patellar Button in Resurfacing Less than 20 mm Thin Patella: A Matched Pair Analysis

Restoring the native patellar thickness after patellar resurfacing provides optimal function of the knee after arthroplasty and minimises complications related to the patellofemoral articulation. The aim of this study was to assess the usefulness of a thin patellar button (6.2 mm) in patients with a patella thickness of less than 20 mm during total knee arthroplasty.

This is a retrospective case control study. A total of 54 female patients with an intraoperative patellar thickness of ＜20 mm, resurfaced with a patellar button of 6.2 mm in thickness were identified (group 1). They were matched with 54 patients with a patellar thickness of 20-23 mm, resurfaced with a patellar button of 8 mm (group 2), based on age, sex, body mass index, and deformity. A clinical and radiological evaluation was done at a minimum 2-year follow-up.

The preoperative mean patellar thickness was 18.94±1.07 mm and was restored to 19.06±0.79 mm in group 1, as compared to 21.63±0.99 mm and 21.72±0.99 mm in group 2. The mean postoperative range of motion was 122.22°±9.25° in group 1 and 123.52°±8.72° in group 2 (p=0.13). No patellar bone or button related complications were observed in any patient in either group.

The 6.2 mm thin patella is useful to restore the native thickness in patients with a patellar thickness of less than 20 mm without risk of button fracture, loosening or overstuffing.