Breakage and Migration of Metal Wires in Operated Patella Fractures: Does it Correlate with Time?

Abstract

Background Tension-band wiring with metal wires is a commonly used technique to treat transverse patella fractures. Wire breakage and migration may potentially cause complications or morbidities such as nerve irritation or skin impingement. The need of extra wound or surgery for implant removal may be required. We hypothesize that the breakage of patellar tension-band wires is related to the patient's age and the length of time after fracture fixation. Methods We retrieved and analysed our 11 years records (from January 1, 2000, to May 31, 2011). The inclusion criteria were: (1) patients with transverse patella fracture treated with tension-band plus cerclage wiring technique, (2) with their metal wires removed in our hospital, (3) unilateral patella fracture, (4) wire removal not due to infection, (5) wire removal after complete fracture union, (6) no fracture distal pole or partial patellectomy with protective wire loop, and (7) known exact date of the initial fracture fixation surgery. We reviewed the reasons of wire removal, the presence of broken or migrated wires upon implant removal, and the time lapse from fracture fixation to removal of wire. Results A total of 59 cases were recruited and studied. A total of 28 patients had intact wires and 31 patients had broken wires upon implant removal. For the age of patients at fracture fixation, there was no statistically significant difference between the intact wire group and the broken wire group. However, for the length of time from fracture fixation to implant removal, the difference was statistically significant between the two groups of patients. It suggested that the risk of wire breakage increases with time after patellar tension-band wiring. If 12 months was used as a cut-off time, there was a statistically significant association between the duration from fracture fixation to implant removal and the presence of broken wire. There were seven cases of wire migration among the 31 patients with broken wires, and two of them needed an extra open wound at popliteal fossa for implant removal. Conclusions The risk of patellar tension-band wire breakage was associated with increase time lapse from fracture fixation, but not the patients’ age upon fracture fixation. The risk of wire breakage significantly increases after 12 months from the fracture fixation. Wire breakage can lead to further morbidities or complications. Routine removal of wire loops may be indicated. Future prospective longitudinal long-term studies may be required.