Suture anchor fixation of comminuted inferior pole patella fracture-novel technique: suture bridge anchor fixation technique

Purpose: Comminuted inferior pole fractures of the patella are notorious fractures where it is difficult to obtain rigid internal fixation by conventional tension band wiring. The purpose of this study is to evaluate the clinical and radiological outcomes of the suture bridge anchor fixation for these comminuted inferior pole fractures of the patella. Methods: From March 2012 to December 2018, suture bridge anchor fixation for the inferior pole comminuted fracture of the patella was performed in 22 patients. There were 21 patients of inferior pole comminuted fracture and 1 patient of lower periosteal sleeve avulsion fracture. Clinical outcomes including SF-36 score, Knee injury and osteoarthritis outcome score (KOOS) and post-operative range of motion were evaluated. In all patients, suture bridge anchor fixation was performed and, tension band wiring with K wire was added for large fragment fixation in two patients. We evaluated bony union, the patellar height using Insall–Salvati ratio and its complications. Results: Mean age was 46 ± 20 (15–82) years. Mean follow-up period was 25 ± 18 (11–74) months. In all patients, bony union was achieved at postoperative 4 months. At final follow-up, mean SF-36 score was 72 ± 15 (30–91) points and KOOS score was 66.7 ± 16 (43–97). The average range of motion was 134 ± 5 (125–140) degrees. As a complication, one patient developed a wound infection and subsequent osteomyelitis of inferior pole fracture fragment. Compared to the normal knee, the Insall–Salvati ratio of the injured knee averages 0.73 and this smaller ratio less than 0.8 meant patella baja. Conclusions: In the comminuted inferior pole fractures of the patella, suture bridge anchor fixation showed good bony union and satisfactory clinical outcomes at the short-term follow-up and could be a satisfactory alternative treatment option. Even though suture bridge anchor fixation in these fractures caused decreased Insall–Salvati ratio (patella height), any patellofemoral pain and limited range of motion was not developed. Level of evidence: Level IV.