Patellar fractures in elderly patients: a multicenter computed tomography-based analysis.

INTRODUCTION: This study aimed to demonstrate the characteristics of patellar fractures and evaluate clinical outcomes in elderly patients. PATIENTS AND METHODS: Medical records of patients aged ≥ 60 years who presented with patellar fractures were retrospectively reviewed from an institutionally approved multicenter (five institutions) orthopedic database. Patient characteristics and fracture patterns were identified, and the clinical outcomes were investigated. We compared differences according to the injury mechanism (low- vs. high-energy). RESULTS: A total of 202 patients [mean age, 69.4 years (range, 60-88 years); male, 89, female, 113] were included in this study. The mean follow-up period was 14.8 months (range 6-58 months), and 75% of the fractures were from low-energy injuries. According to the AO /OTA classification, the most common type was type C (136 cases, 67.3%; 33 cases, C1; 23, C2; and 80, C3), followed by type A (39 cases), type B (26 cases), and unclassified (1 case). The unclassified case was an intra-articular marginal impaction without cortical breakage. Computed tomography (CT) revealed that of the cases, 66.8% had an inferior pole involvement; 80.7%, a comminuted fragment; and 10.4%, an impacted fracture. A total of 166 fractures (82.2%) were treated surgically. The mean union time and range of motion were 13.1 weeks and 123.8° (range 30-150°), respectively. The Lysholm score was 82.1 ± 12.0, with 65.7% of the cases having excellent or good function. The complication rate was 12.4% (24 cases), including ten, four, two, and five cases of infection, fixation failure, nonunion, malunion, and pin migration, respectively. The reoperation rate was 26.4%. CONCLUSION: Patellar fractures in the elderly were mostly from low-energy injuries, and types C3 and A1 were the most common. CT images demonstrated high rates of an inferior pole involvement and comminution. The complication and reoperation rates were relatively high.