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Proximal Femoral Varus Rotation Osteotomy in Cerebral Palsy:A Prospective Gait Study

Journal of Pediatric Orthopaedics: July-August 2003 - Volume 23 - Issue 4 - p 563
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The first page of the article “Proximal Femoral Varus Rotation Osteotomy in Cerebral Palsy: A Prospective Gait Study” (J Pediatr Orthop 2003;23:321–329) by Mary Murray-Weir et al incorrectly listed the authors. The correct title and authors follow:

Proximal Femoral Varus Rotation Osteotomy in Cerebral Palsy: A Prospective Gait Study

*Mary Murray-Weir, MBA, PT, *Leon Root, MD, *Margaret Peterson, PhD, *Mark Lenhoff, BS, *Laurence Daly, *Cathi Wagner, PT, and †Patricia Marcus, PT

Study conducted at the Hospital for Special Surgery, New York, New York

Summary: This prospective study examined the kinematic and temporal/spatial effects of proximal femoral varus rotation osteotomy (VRO) on the gait of individuals with cerebral palsy from preoperative to 1-year postoperative status. Participants were a consecutive sample of 37 individuals (14 males, 23 females). The analysis consisted of three-dimensional kinematics, temporal/spatial measures, and functional status. A curve representing the difference between the preoperative and 12-month postoperative conditions was calculated for each joint motion. Ninety-five percent confidence intervals were calculated about the mean difference curves using a bootstrapping technique. VRO resulted in improved cosmesis and objective improvement in gait, including a statistically significant increase in hip external rotation and hip extension, a decrease in anterior pelvic tilt, and an increase in knee extension strength. The use of confidence bands to identify surgical outcomes with respect to kinematic variables has enormous value for patients and professionals. Long-term follow-up is needed to see if the aforementioned gains improve. Key Words: cerebral palsy, femoral varus rotation osteotomy, gait, outcomes.

Abnormal femoral antetorsion and coxa valga (3,10,11,15) are common radiographic findings in the cerebral palsy (CP) population and can contribute to progressive hip subluxation (18,21) and dislocation (8). Increased femoral antetorsion (excessive femoral anteversion) (5) causes internal rotation at the hip throughout all phases of gait, regardless of whether assistive devices are used. The studies of Sutherland et al. (23) revealed that in the normal gait cycle, the hip is in external rotation at the beginning of the cycle, and that internal rotation of the hip occurs during the stance phase of gait, peaking at opposite foot strike. At this point the lower extremity begins to externally rotate until mid swing, when maximum external rotation during the gait cycle is achieved. A reversal in direction follows and the amount of external rotation decreases (23). In the normal child a mature gait pattern has developed by age 3 years (23). As leg length increases, stride length and velocity increase, but the relationships between stride characteristics remain unchanged (23). Femoral anteversion is greatest at birth, ranging from 30° to 40° (21), and under normal conditions regresses spontaneously with time. By age 16 it measures approximately 16° (15), and by adulthood the average femoral anteversion is 8° in males and 14° in females. However, in individuals with CP, femoral anteversion often remains abnormally high (10,13). Femoral anteversion can be evaluated clinically by the excessive passive internal rotation and limited external rotation of the hips in the prone position. In the prone position the hip is in extension, the position of walking. The pelvis can be stabilized and the degree of internal versus external rotation can be measured using the leg as a goniometer. Delayed onset of weightbearing, which is common in CP (6), and muscle imbalance (4) are factors in the development of subluxation of the hip in CP (25). Although both femoral anteversion and coxa valga are etiologic factors in acquired hip subluxation in cerebral palsy, Laplaza and Root (13) have reported that increased femoral anteversion has a higher correlation with hip instability in CP patients compared with excessive coxa valga.

Surgical interventions to diminish internal rotation during gait in the CP population have included soft tissue procedures (5,24) and rotation osteotomies (19). Varus rotation osteotomy (VRO) corrects coxa valga and femoral antetorsion (19). In this procedure an osteotomy is performed in the intertrochanteric area of the femur, just at the upper level of the lesser trochanter. The osteotomy is aligned to prevent extension or flexion. After placement of the blade in the greater trochanter and femoral neck, one screw is inserted and range of motion evaluated. The goal is to have approximately a 2:1 ratio of

From the *Hospital For Special Surgery, New York, New York, U.S.A. and †Wenonah Trail, Mohegan Lake, New York.

The Hospital for Special Surgery CP Development Fund provided financial support for this study.

Address correspondence and reprint requests to Mary Murray-Weir, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021.

Copyright © 2003 Wolters Kluwer Health, Inc. All rights reserved.