Separate vertical wiring versus conventional tension band fixation for inferior pole patellar fractures: a prospective cohort study on postoperative patella baja and functional outcomes.

Abstract

To compare the clinical efficacy of the separate vertical wiring (SVW) technique and conventional tension band fixation in managing AO/OTA type A1 inferior pole patellar fractures, focusing on postoperative patella baja incidence and functional recovery. From January 2019 to January 2023, 242 patients with AO/OTA A1 inferior pole patellar fractures undergoing surgical treatment were assigned to the SVW group (n = 117) or tension band (TB) group (n = 125). The primary outcome was the incidence of patella baja (Insall-Salvati index < 0.8) at the 12-month follow-up. Secondary outcomes included knee range of motion (ROM), Böstman functional score, and complications. The SVW group demonstrated a significantly lower incidence of patella baja compared to the TB group (25.6% vs. 52.1%, P < 0.001), with higher mean (Insall-Salvati index) ISI values (0.87 ± 0.16 vs. 0.76 ± 0.12, P < 0.01). Knee ROM was superior in the SVW group (124.0°±14.2° vs. 119.9°±12.4°, P = 0.017), though no significant difference was observed in Böstman scores (25.1 ± 3.5 vs. 24.6 ± 3.6, P = 0.33). The overall complication rate was 5.8% (14/242), primarily comprising surgical site infections (3.5%, 8/242: 1.2% superficial, 2.1% deep), fixation failure (1.2%, 3/242), and nonunion (0.8%, 2/242). Notably, soft tissue irritation occurred exclusively in the TB group (8.8%, 11/125 vs. 0% in SVW; P = 0.005). The SVW technique significantly reduces the risk of patella baja and improves knee range of motion by optimizing vertical tension distribution, establishing it as a biomechanically superior fixation strategy for AO/OTA A1 inferior pole patellar fractures. These findings support SVW as a first-line treatment for such complex injuries.