Weight Percentile is Maintained During Spica Casting: A Retrospective Cohort Study of Patients Treated with Closed or Open Reduction for Developmental Dysplasia of the Hip

Abstract

BackgroundWeight changes during spica casting previously have not been reported. The primary aim of this study was to determine weight percentile change from cast initiation to cast removal. Secondary aims were to assess weight percentile changes from initiation to mid-term follow-up visits after cast removal, and to assess mean weight change from cast initiation to cast removal. MethodsPatients with developmental hip dislocation (DDH) treated with closed or open reduction (+/- femoral/pelvic osteotomy) and spica cast were retrospectively reviewed from 2/2016-6/2023. Patients <4 years treated for ≥6 weeks in spica cast were included. Patients lacking weight measurements within the 4 weeks prior to cast initiation or within 2 weeks following cast removal were excluded. Demographics, weight and weight percentiles at cast initiation, cast removal, and at follow-ups were collected. Mean weights and mean weight percentiles were compared across visits with dependent sample t-tests and one-way ANOVA tests based on normality, with significance threshold of p≤0.05. Results36 hips in 31 infants (median age 10.4 [IQR 9, 16.3] months, 86% female) were included. Median duration of casting was 9.2 [IQR 7.9, 12.6] weeks; 2 hips had midpoint cast change. Mean weight was 9.8±2.3 kg at cast initiation and 10.1±1.9 kg at final cast removal, with mean change of 0.3±0.4 kg (p=0.527). Mean weight percentiles did not differ during or after treatment (range 55-61st percentile, p=0.974). ConclusionWeight percentiles were maintained during spica casting in the patients examined in this study, which should be reassuring to the family and treatment team; our study did not find that spica casting stunts weight gain. For surgeons who may consider maintaining the original spica cast throughout treatment, without cast change, mean weight gain of 0.3 kg for mean casting length of 9 weeks in infants of median age 10.4 months should be reassuring; many infants/toddlers may not require a cast change due to growth. Level of EvidenceIII, retrospective cohort