Flexion deformity of the knee is a common presentation in children with cerebral palsy with hamstring surgery as an option for addressing this. However, concerns with regard to increased pelvic tilt have been raised. The purpose of this study was to compare preoperative and postoperative pelvic tilt after isolated hamstring lengthening versus combined hamstring lengthening and the influence of Gross Motor Function Classification System (GMFCS) levels on pelvic tilt.
This retrospective study included 46 ambulatory children with cerebral palsy who had had open medial hamstring lengthening (mean age at surgery, 11 y 11 mo; SD, 2 y 11 mo; GMFCS I, 16; GMFCS II 20; GMFCS III 10). Twelve children underwent isolated surgery and 34 children underwent combined surgery. The isolated hamstring procedures could be combined with foot and/or ankle-level surgery, as only the hamstring procedure would affect the pelvic tilt. Combined surgery was defined as hamstring lengthening with other procedures performed at the knee or more proximally. The preoperative and postoperative 3-dimensional gait analysis data were evaluated in this study.
Both the isolated and combined hamstring lengthening groups showed no significant change in pelvic tilt ([INCREMENT]1.28, P=0.203; [INCREMENT]1.47, P=0.113, respectively). A significant change in pelvic tilt was seen in children functioning at GMFCS III ([INCREMENT]4.66, P=0.009) but not GMFCS I and II ([INCREMENT]0.37, P=0.718; [INCREMENT]0.48, P=0.697). Significant postoperative decreases in the knee flexion angle at initial contact were seen for both isolated ([INCREMENT]5.72, P=0.010) and combined hamstring lengthening ([INCREMENT]10.95, P<0.001).
Hamstring lengthening, for the majority of patients, did not lead to a clinically significant change in mean pelvic tilt and improved knee flexion angle at initial contact. Children who functioned at GMFCS level III had an increase in anterior pelvic tilt and caution should be exercised in this group.
Level IV evidence—case series.
*East Lancashire Hospitals NHS Trust, Burnley, UK
‡Alder Hey Children’s Hospital, Liverpool, UK
†Department of Surgery, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
M.P.C.W.: study design, data collection, statistical analysis, and manuscript preparation. N.W.: study design, data collection, and manuscript preparation. D.T.: participant identification, performed measurements, and gait laboratory data analysis. G.H.: participant identification and performed measurements. A.A.B., D.M.W., and R.D.M.W.: study design and manuscript preparation.
This study did not receive external funding from any source.
The authors declare no conflicts of interest.
Reprints: Nichola C. Wilson, MBChB, PhD, FRACS, Department of Surgery, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand. E-mail: firstname.lastname@example.org.