Clinical and surgical factors influencing screw breakage during hardware removal following periacetabular osteotomy

Periacetabular osteotomy (PAO) is a procedure used to treat patients with hip dysplasia. Current literature reports symptomatic hardware removal (HWR) rates of 13.6% following PAO. No reports have examined the incidence of or factors relating to screw breakage during HWR. This study reports the incidence of screw breakage in patients undergoing HWR following PAO and examines the associated clinical and surgical factors. Patients who underwent PAO by a single surgeon from 2012 to 2022 were retrospectively reviewed. Demographic, surgical, and implant information was collected. Constructs were stratified by number (three-screw and four-screw) and type (3.5 mm only, 4.5 mm only, and mixed). Incidence rates of HWR and screw breakage were calculated. Three hundred and two hips from 254 patients undergoing PAO were included. Seventy-one hips from 58 patients underwent HWR (23.5%). Eighteen of 259 screws (6.9%) were broken upon removal in 10/71 hips (14.1%). Significantly more 3.5-mm screws were removed (24.7% vs 21.2%; P = .05) and broken than 4.5-mm screws (10.5% vs 3.8%; P = .04). Time to removal was significantly longer in broken screws (16.8 ± 12.7 months vs 33 ± 18.2 months, P < .001). The use of 3.5-mm screws and increased time from implantation to removal are associated with higher rates of screw breakage during HWR following PAO. The use of 4.5-mm screws and earlier time to removal (less than 12 months) both decrease the probability of breakage.