BEST PAPER Gait and Clinical Motion Analysis Society meeting 2024: The prevalence and risk factors associated with anterior pelvic tilt in ambulatory youth with cerebral palsy.

Abstract

Background: Excessive anterior pelvic tilt (APT) in youth with cerebral palsy (CP) may be associated with back pain and functional limitations. This study aimed to determine risk factors for excessive APT and significant change during childhood in ambulatory youth with CP.

Methods: This institutional review board-approved retrospective study identified youth with bilateral spastic CP and multiple gait analyses. Pairs of gait analyses were used to measure change in pelvic tilt. A mixed effects linear regression analysis predicted patient and surgical factors associated with change in pelvic tilt. A logistic mixed effects generalized linear regression identified factors associated with an increase in anterior pelvic tilt.

Results: Meeting inclusion criteria were 503 youth [female: 207/male: 297; Gross Motor Function Classification System I (n = 50), II (n = 328), and III (n = 125)]. Pairs of gait analyses (n = 632) were analyzed: age 11 ± 4 y at visit 1 and 13 ± 6 y at visit 2. Five hundred twenty-six pairs of gait analyses had intervening surgery; 106 had no surgery. Pelvic tilt was 20 ± 9° anterior at visit 2 in both the surgery and no surgery groups (p = 0.63). Prior selective dorsal rhizotomy, older age, and medial+lateral hamstring lengthening (HL) were significant factors associated with increases in APT; Achilles lengthening, higher gross motor function score, and high APT at visit 1 were protective. The mean change in pelvic tilt after medial only vs medial+lateral HL was 1 ± 9° (p = 0.046) and 4 ± 9° (p < 0.0001), respectively.

Significance: Risk factors associated with increased APT for youth with CP were multifactorial, with prior selective dorsal rhizotomy and high-dose HL having the most significant negative effects. Contrary to conventional thinking, high initial APT was not associated with further progression. Risk factors for progression of APT should be considered when developing a surgical plan, particularly for youth with a normal or posteriorly tilted pelvis, given the susceptibility to more change in pelvic tilt.

Level of evidence: Level III.