Abstract
Purpose:
This study attempts to establish whether biomechanical manipulation through distraction can result in fracture union.
Method:
A retrospective clinical audit of 15 patients with delayed or hypertrophic non-unions treated successfully with closed distraction in circular external fixation. Average time to union, complications and complication rates were also reviewed. Inclusion criteria: all patients with delayed or hypertrophic non-union, treated by closed distraction between 2004 and 2011.
Results:
Fifteen patients included in the study. The average time to union was 188 days. The most common complication was local pin tract sepsis. The most serious complication was a broken fixation ring that needed replacement.
Conclusion:
Biomechanical fracture strain is calculated by dividing the fracture gap distance by the change in the fracture distance i.e. FRACTURE STRAIN = DIFFERENCE IN L/L Hypertrophic non-union occurs when the fracture strain is more than 10 %. This formula shows that by increasing the fracture gap, the fracture strain will decrease This concept is contrary to the current practice of compressing the fracture. This study shows that distraction can be used to manipulate the biomechanical circumstances that dictate the development of fracture non-union. Furthermore ring fixators are ideal devices to use for biomechanical manipulation.
