Comminuted AO-C3 fractures of the patella: good outcome using anatomically contoured locking plate fixation

The treatment of comminuted patellar fractures remains a challenge for orthopedic surgeons. The aim of this study was to assess the clinical, functional, and radiological outcome after treatment of comminuted patellar fractures using an anatomically contoured plating system.

Between January 2015 and December 2019 (5 years), 29 patients with complex C3 fractures according to AO classification (18 female, 11 male; mean age: 53 years) were treated using an anatomically contoured plating system (patella SuturePlate™, Arthrex®, Naples, USA). Indication for surgery was based on instability and/or initial fragment dislocation (> 2 mm). After a minimum follow-up of 12 months, patients were examined using a standardized clinical examination and functional outcome was assessed using specific knee scores (Lysholm, WOMAC, IKDC, Kujala, and Tegner score). In addition, complications were recorded and all available radiographs were evaluated regarding osteoarthritis and reduction quality.

All patients returned for follow-up investigation after an average of 19 months (range: 12-48 months). A mean range of motion (ROM) of 131° (range: 100-150) was recorded. Overall good functional outcome parameters could be reported, with a mean Lysholm score of 84.7 (range: 100-45), a WOMAC of 5.1 (range: 0-19.2), a Kujala scale of 85.5 (range: 100-48), an IKDC of 76.6 (range: 100-44.8), and a Tegner score of 4.3 (range: 10-3) with a difference of 0.62 to pre-operative. Patient satisfaction was rated 8.4 (range: 4-10) using a VAS. No loss of reduction, mechanical failure, or implant complications were detected. Radiological follow-up showed no evidence of relevant post-traumatic retropatellar osteoarthritis. In 7 cases, implants were removed due to subjective mechanical irritation.

Anatomically contoured patellar plates allow secure fixation of the fracture fragments even in comminuted cases. Especially when tension-band wiring is prone to early failure, locking plate fixation represents a viable option leading to good functional results and low complication rates.