Locked tension band wiring using ring pins for patellar fractures: a method of minimising implant migration.

ABSTRACT

BACKGROUND: A modified K-wire attached with ring (ring pin) was used to treat a displaced patellar fracture, and the ring pin was locked with tension band wiring. The purpose of this study was to evaluate the surgical outcome of this method with respect to its procedural safety. METHODS: The authors retrospectively reviewed 36 patients treated for a displaced patellar fracture and assessed bone union, fixation failure, postoperative pain, range of motion, and incidence of hardware removal. Clinical outcome was evaluated using the Böstman scoring system. The mean follow-up period was 27 (range 13-47) months. RESULTS: Bony union was achieved in all patients. No fixation failure and pin migration were detected. Hardware was removed in three cases (8.3 %). Reasons for removal were pain in one case and vague discomfort in two cases. The average Böstman scores at 12 months postoperatively were 29.6, with 34 (94.4 %) patients graded as excellent. The average active flexion of the knee joint was 130.4° (range 125°-150°), with an average flexion contracture of 3° (range 0°-10°). CONCLUSIONS: This implant could facilitate satisfactory fixation, restore the integrity of the extensor mechanism, and reduce the possibility of implant migration and implant-related discomfort.