Outcomes of open reduction for hip dislocations in children with connective tissue disorders.

Purpose: While children with hypermobility and/or ligamentous laxity due to coexisting connective tissue disorders might be expected to have worse outcomes after open reduction for hip dislocations, there is minimal prior research on this topic.

Methods: All open reduction surgeries for hip dislocations performed at a single urban, tertiary-care children's hospital from 2009 to 2023 were reviewed retrospectively. Those with connective tissue disorders secondary to a diagnosed syndrome or genetic disorder were included. Patients with <1 year of follow-up or hip instability in the setting of Trisomy 21 were excluded. Clinical and radiographic data was collected. Instances of re-dislocation, proximal femoral growth disturbance, residual acetabular dysplasia, and arthrofibrosis were recorded.

Results: Twenty-three hips (15 patients) were included. Mean age at the time of surgery was 19.6 months (Range: 8.2-36.0 months), and mean follow-up was 4.3 years. The most common connective tissue disorder condition included was Ehlers-Danlos syndrome (13%). A majority of open reductions were performed via an anterior approach (96%). Seven hips (30%) underwent a concomitant pelvic osteotomy without femoral osteotomy and seven hips (30%) underwent both pelvic and femoral osteotomies. Twenty-two hips (96%) were International Hip Dysplasia Institute grade 1 at the final follow-up. Re-dislocation occurred in four hips (17%); eight hips (35%) demonstrated residual acetabular dysplasia, five hips (22%) demonstrated proximal femoral growth disturbance, and nine hips (39%) developed stiffness postoperatively.

Conclusions: Patients with connective tissue disorders and ligamentous laxity have comparable rates of residual acetabular dysplasia, proximal femoral growth disturbance, and (surprisingly) stiffness as typical developmental dysplasia of the hip following open hip reduction surgery. Although the re-dislocation rate in the connective tissue disorders group was approximately 2-3 times higher, the difference did not reach statistical significance. Given that the study was limited by a low sample size, however, it is possible that the findings of no difference in residual acetabular dysplasia and proximal femoral growth disturbance were potentially due to a lack of power.

Level of evidence: IV.