Lower limb malrotation following MIPO technique of distal femoral and proximal tibial fractures

Abstract

Objective To determine the incidence of rotational malalignment in distal femoral and proximal tibial fractures using computed tomography (CT) scanograms following indirect reduction and internal fixation with the minimally invasive percutaneous osteosynthesis (MIPO) technique. Design Prospective Cohort. Setting Level I Trauma Centre. Patients/Participants A total of 27 consecutive subjects, and 14 proximal tibia and distal femur fractures. Intervention All patients underwent indirect reduction and internal fixation with a MIPO plating system. A CT scanogram to measure rotational malalignment between the injured and non-injured extremity was then undertaken. Main outcome measure(s) Femoral anteversion angles and tibial rotation angles between the injured and non-injured extremities were compared. Malrotation was defined as a side-to-side difference of >10°. Results A total of 14 postoperative tibias and 13 femurs underwent CT scanograms. Three females and 11 males with an average age of 38.1 years sustained proximal tibia fractures and six females and seven males with an average age of 55.8 years sustained distal femur fractures. The difference between tibial rotation in the injured and the non-injured limbs ranged from 2.7 to 40.0° with a mean difference of 16.2° ( p = 0.656, paired T-test). Fifty percent of the tibias fixed with MIPO plates were malrotated >10° from the uninjured limbs. The difference between femoral anteversion in the injured and non-injured limbs ranged from 2.0 to 31.3° with a mean difference of 11.5° ( p = 0.005, paired T-test). A total of 38.5% of the distal femurs fixed with MIPO plates were malrotated >10° from the uninjured limb. Conclusions Following fixation of distal femoral and proximal tibial fractures, the incidence of malrotation was 38.5% and 50%, respectively. The difference of the mean measures was significant for femoral malrotation; however, statistical significance could not be demonstrated for tibial malrotation. The incidence of malrotation following MIPO plating in this study is much higher than that quoted in previous studies.