Influence of gait analysis on decision-marketing for lower extremity surgery

Motor control as a factor in functional outcome associated with rectus femoris transfer


  1. 1. Center for Gait and Movement Analysis (CGMA), The Children’s Hospital;
  2. 2. University of Colorado at Denver & Health Sciences Center, Denver, CO, USA

Background/Objectives: In children with spastic cerebral palsy (CP), stiff knee gait is cahraterized by reduced dynamic knee range of motion (KROM) and decreased peak knee flexion in swing-phase (PKFSW). Surgery involving a rectus femoris transfer (RFT) posterior to the knee axis, combined with hamstring release,ameliorates biomechanical constraints to knee flexion while preserving adequate knee extension in stance period. 1. Muthusamy et al. 2. reported a group effect of significantly increased knee flexion in swing, with no increased flexion in stance in a group of 38 children (70 legs). However, not all individuals demonstrated a clinically significant functional gain in PKFSW. We propose that functional gains after RFT are dependent on motor control changes that exploit the biomechanical advantages afforded by the RFT. The objective of this study is to examine in coordination associated with RFT.

Design: A retrospective outcome study.

Participants/Setting: A subgroup of the cohort reported by Change et al. 2. included 21 ambulatory patients (35 legs) with a diagnosis of spastic CP between the ages of 3 and 21 who walked without assistive devices and underwent concomitant RFT and hamstring lengthening procedures. Of these, 14 (Group A) met the functional criteria of greater than 5 0 increased PKFSW with less than 5 0 increased knee flexion during loading response. Twenty-one samples (Group B) did not.

Materials/Methods: Changes in KROM were noted by the increase in popliteal angle, dynamic KROM, and improvement in Duncan-Ely test postoperatively. Coordination of the thigh and shank as they cycle between flexion/extension was measured through continuous relative phase (CRP) plots. CRP plots can describe the inter-segmental limb coupling of these segments in children with CP. 3. CRP values measured were: (1) maximum when the shank trajectory leads for single limb support; (2) minimum when the thigh trajectory leads to initiate limb advancement; and (3) maximum when the shank trajectory leads at terminal swing.

Results: Both groups showed similar change in dynamic KROM, popliteal angle, and Duncan-Ely test. Group A improved at all CRP values with significant (p<0.05) improvements seen for II and III. Significant (p<0.05) improvements were only seen in Group B at I (Fig. SP:38).

Conclsuions/Significance: The changes in CRP values demonstrated that intrinsic coordination of the thigh and shank in children with stiff knee gait can be restored after RFT and hamstring lengthening. While both groups demonstrated  similar changes in KROM, only Group A, who demonstrated improved pre-swing and swing-period coordination.Impaired motor control, required for limb coordination, in the feed-forward mode, may be a limiting factor to functional change after RFT.


  1. 1. Gage JR, Perry J, Hicks RR, Koop S, Werntz JR. (1987) Rectus femoris transfer as a means of improving knee function in cerebral palsy. Develop Med Child Neurol29:159-166.
  2. 2. Muthusamy K, Seidl AJ, Friesen RM, Zhaoxing P, Carollo JJ, Change FM. (2006) Rectus femoris transfer in children with cerebral palsy: evaluation of transfer site and preoperative indicators. Gait Posture 29:S137-S138.
  3. 3. Stergiou N, editor. (2004) Innovative Analyses of Human Movement, p93-119.
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