CLINICAL APPLICATION OF AXIAL LOAD MECHANICAL TESTING IN REMOVING EXTERNAL FIXATOR AFTER TIBIA AND FIBULA FRACTURES SURGERY / 中国修复重建外科杂志

ABSTRACT

OBJECTIVE: To explore the efficacy and safety of the axial load mechanical testing for removing external fixator. METHODS: Between January 2014 and August 2015, 27 patients with tibia and fibula fractures caused by trauma underwent an external fixation. Of 27 patients, 21 were male and 6 were female with the average age of 45 years (range, 19-63 years), including 7 cases of closed fracture and 20 cases of open fracture. X-ray film results showed spiral unstable fracture in 4 cases and comminuted unstable fracture in 23 cases. All patients underwent an external fixation. Bone nonunion occurred in 3 cases because of infection, and bone nonunion combined with bone defect occurred in 1 case, who received tibial osteotomy lengthening surgery. When X-ray film showed continuity high density callus formation at fracture site, axial load mechanical test was performed. If the axial load ratio of external fixator was less than 10%, the external fixator was removed. RESULTS: At 21-85 weeks after external fixation (mean, 44 weeks), axial load mechanical test was performed. The results showed that the axial load ratio of external fixation was less than 10% in 26 cases, and the external fixator was removed; at 6 weeks after removal of external fixator, the patients could endure full load and return to work, without re-fracture. The axial load ratio was 14% in 1 case at 85 weeks, and the X-ray film result showed that fracture did not completely heal with angular deformity; re-fracture occurred after removing external fixator, and intramedullary fixation was used. CONCLUSIONS: External fixator axial load mechanical testing may objectively reveal and quantitatively evaluate fracture healing, so it is safe and reliable to use for guiding the external fixator removal.