O2141: Incidence and Outcomes of Femoral Nerve Palsy in the Treatment of Developmental Dysplasia of the Hip with Pavlik Harness

Background: Pavlik harness is well established as a successful treatment for infants with developmental dysplasia of the hip. Transient femoral nerve palsy (FNP) is an uncommon but significant complication of this treatment. This study aims to identify the treatment trajectory of these patients, who we hypothesise have a significantly higher rate of alternative brace requirements, closed and/or open hip reduction.

Methods: We performed a retrospective review of all patients undergoing Pavlik harness treatment for developmental dysplasia of the hip between 2016 and 2024. All of those with FNP development were identified and reviewed. A control group of 50 patients undergoing Pavlik harness treatment for confirmed hip dislocation without femoral nerve palsy was randomly selected during the same time period.

Results: 22 patients from a cohort of 1118 were identified as having FNP, with an occurance rate of 2.0%. 11/22 (50%) of cases presented 7 or more days after harness application. Patients who developed FNP had a 32% chance of overall treatment success with Pavlik harness alone, as opposed to 86% with the control group (p=0.03). In 8 patients, the femoral nerve palsy was not recognized by parents and only identified at routine clinic follow-up. 54% of FNP cases required a closed or open reduction in the operating room, as opposed to 14% of the control group (p=0.005). There were no fixed/irreducible dislocations in the control group, whereas 5/22 (22%) of those in the femoral nerve palsy cohort had fixed/irreducible hips.

Conclusion: This study reinforces the literature on the incidence of femoral nerve palsy with Pavlik harness treatment, and confirmed our hypothesis that it portends a much higher likelihood of treatment failure with Pavlik harness treatment alone. Caregivers should be counseled about this to meet expectations in treatment should this complication arise, and to be vigilant for its onset. Given low likelihood of success with Pavlik harness in setting of FNP, early transition to alternative braces may be worthwhile, especially for those with clinically reducible hips.