Less in-toeing after femoral derotation osteotomy in adult patients with increased femoral version and posterior hip impingement compared to patients with femoral retroversion

In-toeing of the foot was associated with high femoral version (FV), while Out-toeing was associated with femoral-retroversion. Therefore, we report on (i) foot-progression-angle (FPA), (ii) prevalence of In-toeing and Out-toeing, and (iii) clinical outcome of patients treated with femoral-derotation-osteotomy (FDO). We performed a retrospective analysis involving 20 patients (20 hips) treated with unilateral FDO (2017-18). Of them, 14 patients had increased FV, 6 patients had femoral-retroversion. Follow-up time was mean 1 +/- 1 years. All patients had minimal 1-year follow-up and the mean age was 29 +/- 8 years. Patients with increased FV (FV > 35 degrees) presented with positive posterior-impingement-test and mean FV was 49 +/- 11 degrees (Murphy method). Six patients with femoral-retroversion (FV < 10 degrees) had positive anterior impingement test and mean FV of 5 +/- 4 degrees. Instrumented gait analysis was performed preoperatively and at follow-up using the Gaitrite system to measure FPA and was compared to a control group of 18 healthy asymptomatic volunteers (36 feet, mean age 29 +/- 6 years). (i) Mean FPA increased significantly (P = 0.006) from preoperative 1.3 +/- 7 degrees to 4.5 +/- 6 degrees at follow-up for patients with increased FV and was not significantly different compared to the control group (4.0 +/- 4.5 degrees). (ii) In-toeing decreased from preoperatively (five patients) to follow-up (two patients) for patients with increased FV. Out-toeing decreased from preoperatively (two patients) to follow-up (no patient) for patients with femoral-retroversion. (iii) Subjective-hip-value of all patients increased significantly (P < 0.001) from preoperative 21 to 78 points at follow-up. WOMAC was 12 +/- 8 points at follow-up. Patients with increased FV that underwent FDO walked with less In-toeing. FDO has the potential to reduce In-toeing and Out-toeing and to improve subjective satisfaction at follow-up.