[Medial rotation deformity of the hip in cerebral palsy: surgical treatment by transposition of gluteal muscles].

INTRODUCTION Medial rotation deformity of the hip is a problem to patients who are handicapped by cerebral palsy but able to walk, because the knees point inward during gait ("kissing patellae") and cause falls and frequent injuries. Knees and ankles are subject to stress and, therefore, they assume compensating positions. Lower legs assume position of valgus and external rotation, whereas feet rotate either inwards or outwards. Secondary deformities make gait more difficult and cause rapid tear of footwear. AIM The purpose of the paper was to retrospectively analyze the effects of transposition of the gluteus medius and minimus muscles, a procedure introduced for the first time in our country in order to correct the deformity. A new method of binding the muscles by wire was described. There had been no previous experience with this method. METHOD This operation was indicated in patients with spastic form of cerebral palsy, who were able to walk, who had difficulties in gait and whose lateral rotation was less than 10 degrees along with the medial rotation of over 70 degrees of the hip on the side of the deformity. Additional prerequisite for the operation was the absence of flexion contracture of more than 15 degrees of either the hip or the knee on the side of deformity, as there is possibility of aggravation of the flexion hip deformity due to transposed gluteal muscles (now in front of the hip joint). Fifteen hips of 10 patients were operated on. Five patients were operated on bilaterally at one time. The average age was 8 (6-12) years. The majority of patients, 8 (80%) were aged between 6 and 8. The average follow-up was 5 years (3-8). The assessment of the results was based on the comparison of rotational abilities of both hips before and after the operation (in unilateral and bilateral deformities), as well as on individual complaints before and after the operation. In patients with unilateral deformity, their "healthy" hips were the control hips. The analysis of the femoral neck anteversion before and after operation was performed. RESULTS Average values of medial and lateral rotation of the deformed hips before operation exhibited significant statistical difference when compared to control hips. The difference of average values of rotatory movements of control and operated hips was not statistically significant after operation. The difference of average preoperative values of the femoral neck anteversion in hips with deformity was statistically significant (49.40+/-4.63 degrees compared to 32.8+/-3.11 degrees ). Postoperative average values of anteversion in operated and control hips were not statistically significant. The difference between average preoperative (49.40+/-4.63 degrees ) and postoperative (35.80+/-7.66 degrees ) values of the femoral neck anteversion was statistically significant. Excellent results were achieved in 5 (50%) patients, i.e. 8 (53.3%) hips; good results were achieved in 3 (30%) patients, i.e. 5 (33.3%) hips; poor result in 2 (20%) patients, i.e. 2 (13.3%) hips. All 5 patients who had undergone surgery of both hips had symmetric outcome. Three patients had excellent results, while two had good results. Patients with excellent and good results (80% of patients, 86.6% of hips) showed neither weakening of the operated hip abduction nor pelvic instability (positive Trendelenburgh hip test). No complications were recorded postoperatively. CONCLUSION Transposition of gluteal muscles can be recommended in patients under 10 years of age as there is still a chance for their femoral neck to change orientation, to decrease the anteversion and thus to achieve long-lasting effect. Fixation of transposed muscles by wire proved to be effective.