OPTIMIZING TIME IN HARNESS: FACTORS ASSOCIATED WITH SONOGRAPHIC RESOLUTION OF DEVELOPMENTAL DYSPLASIA OF THE HIP DURING PAVLIK TREATMENT

The primary aims of this study were to determine the time to sonographic correction of decentred hips during treatment with Pavlik harness for developmental dysplasia of the hip (DDH) and investigate potential risk factors for a delayed response to treatment. This was a retrospective study of infants with decentred hips who underwent a comprehensive management protocol with Pavlik harness between 2012 and 2016. Ultrasound assessments were performed at standardized intervals and time to correction from centring of the femoral head was quantified. Hips with 50% FHC and alpha angles >60° were considered corrected. Survival analyses using log-rank tests and Cox regression were performed to investigate potential risk factors for delayed time to correction. 108 infants (158 hips) successfully completed the bracing protocol and were included in the study. Mean age at treatment initiation was 6.9 ± 3.8 weeks. All included hips centred within two weeks of treatment initiation. At two, five, eight- and 12-weeks following centring of the femoral head, 13% (95% CI: 8-19%), 67% (95% CI: 60-74%), 98% (95% CI: 95-99%) and 99% (95% CI: 98-100%) of hips had cumulatively achieved sonographic correction. Low alpha angles at presentation were found to be a risk factor for delayed time to correction (HR per 1° decrease in alpha angle 1.04, CI 1.01 – 1.06, p = 0.006). The majority of decentred hips undergoing Pavlik treatment achieved sonographic correction within eight weeks of centring and radiological severity at presentation was a predictor for slower recovery. These findings provide valuable insights into hip development during Pavlik treatment and will inform the design of future prospective studies investigating the optimal time required in harness.