Testing of an Ultrasound-Limited Imaging Protocol for Pavlik harness Supervision (TULIPPS) in developmental dysplasia of the hip: a randomized controlled trial

Aims There is no consensus regarding optimum timing and frequency of ultrasound (US) for monitoring response to Pavlik harness (PH) treatment in developmental dysplasia of the hip (DDH). The purpose of our study was to determine if a limited-frequency hip US assessment had an adverse effect on treatment outcomes compared to traditional comprehensive US monitoring. Methods This study was a single-centre noninferiority randomized controlled trial. Infants aged under six months whose hips were reduced and centred in the harness at initiation of treatment (stable dysplastic or subluxable), or initially decentred (subluxated or dislocated) but reduced and centred within four weeks of PH treatment, were randomized to our current standard US monitoring protocol (every clinic visit) or to a limited-frequency US protocol (US only at end of treatment). Groups were compared based on a angle and femoral head coverage at the end of PH treatment, acetabular indices, and International Hip Dysplasia Institute (IHDI) grade on one-year follow-up radiographs. Results Overall, 100 patients were included; 42 patients completed the standard protocol (SP) and 40 completed the limited protocol (LP). There was no significant difference in mean right a angle at the end of treatment (SP 70.0 degrees (SD 3.2 degrees); LP 68.7 degrees (SD 2.9 degrees); p = 0.033), nor on the left (SP 69.0 degrees (SD 3.5 degrees); LP 68.1 degrees (SD 3.3 degrees); p = 0.128). There was no significant difference in mean right acetabular index at follow-up (SP 23.1 degrees (SD 4.3 degrees); LP 22.0 degrees (SD 4.1 degrees); p = 0.129), nor on the left (SP 23.3 degrees (SD 4.2 degrees); LP 22.8 degrees (SD 3.9 degrees); p = 0.284). All hips had femoral head coverage of > 50% at end of treatment, and all were IHDI grade 1 at follow-up. In addition, the LP group underwent a 60% reduction in US use once stable. Conclusion Our study supports reducing the frequency of US assessment during PH treatment of DDH once a hip is reduced and centred.