Predicting duration of Ilizarov frame treatment for tibial lengthening

Aim: To predict duration of treatment for tibial lengthening, as a function of target length increase.Method: Review of case notes and radiographs of patients undergoing Ilizarov method of tibial distraction osteogenesis.Results: In the 27 cases suitable for analysis, the median age was 29.9 years (13.3 to 72.6 years), and the median distraction was 3.5 cm (1.0 to 7.2 cm). A positive linear relationship (r = 0.7) was demonstrated between the distraction length (x, in cm) and the frame duration (y, in days), according to the equation y = 54x + 94. A negative hyperbolic relationship was also demonstrated between rate of bone healing and distraction length (r = 0.6), with distractions over 3.0 cm healing significantly faster than shorter ones (P< 0.03).