Long-term outcomes after partial patellectomy in comminuted fractures — a clinical study

Purpose The purpose of this study was to evaluate the long-term clinical and radiographic outcomes of partial patellectomy (PP) in patients with patella comminuted distal pole fractures. Methods Seventeen patients who were diagnosed with patella comminuted distal pole fractures and underwent PP procedures were retrospectively included between January 1995 and January 2005. We collected patient demographics and data on the mechanism of injury, time to surgery, fracture type, follow-up time, and post-operative complications (infection, patellofemoral arthritis, and stiffness). At the final follow-up, functional outcome was evaluated by the range of motion (ROM) and the Bostman Scoring System. Quadriceps strength was evaluated by using an isokinetic dynamometer to measure peak torque, and patellar height was evaluated by the Insall-Salvati (IS) ratio in lateral knee radiographs. The average follow-up period was 14.6 years (range, 11–19 years). Results We analyzed 17 patients (AO/OTA 34-A1), with an average age of 59.8 years (range, 43–76 years). According to the Bostman grading scales, final functional outcomes were excellent in 11 (64.7%) and good in six (35.3%) patients. All patients had full knee extension, and the average ROM was 125.1° (range, 121.4–129.3°). The average peak torque of the injured knee was 103.2 ± 9.7 Nm, and that of the uninjured opposite side was 108.3 ± 7.6 Nm, with no significant difference ( p > 0.05). Furthermore, no postoperative complications, such as infection, posttraumatic osteoarthritis, or stiffness, were observed. Compared to the uninjured knee, the IS ratio of the injured knee was 0.76 ± 0.13, indicating that the patellar height was decreased, which meant patella baja. Conclusions The PP procedure for patella comminuted distal pole fractures is a safe, simple, and reliable technique that can provide good long-term clinical outcomes even with decreased patellar height and could be a satisfactory alternative treatment option when anatomical reduction is difficult.