title: The incidence of stress fracture following peri-acetabular osteotomy: an under-reported complication.
abstract: Stress fractures occurring in the pubis and ischium after peri-acetabular osteotomy (PAO) are not well recognised, with a reported incidence of 2% to 3%. The purpose of this study was to analyse the incidence of stress fracture after Bernese PAO under the care of two high-volume surgeons. The study included 359 patients (48 men, 311 women) operated on at a mean age of 31.1 years (15 to 56), with a mean follow-up of 26 months (6 to 64). Complete follow-up radiographs were available for 348 patients, 64 of whom (18.4%) developed a stress fracture of the inferior pubic ramus, which was noted at a mean of 9.1 weeks (5 to 55) after surgery. Most (58; 91%) healed. In 40 of the patients with a stress fracture (62.5%), pubic nonunion also occurred. Those with a stress fracture were significantly older (mean 33.9 years (16 to 50) vs 30.5 years (15 to 56), p = 0.002) and had significantly more mean pre-operative deformity: mean centre-edge angle (9.8° (-9.5 to 35) vs 12.4° (-33 to 28), p = 0.04) and mean Tönnis angle (22.8° (0 to 45) vs 18.7° (-2 to 38), p < 0.001). The pubic nonunion rate was significantly higher in those with a stress fracture (62.5% vs 7%, p < 0.001), with regression analysis revealing that these patients had 11.8 times higher risk than those without nonunion.
authors.affiliation: Northumbria Healthcare NHS Foundation Trust, Wansbeck General Hospital, Woodhorn Lane, Ashington, NE63 9JJ, UK.
authors.forename: A
authors.initials: A
authors.lastname: Malviya
authors.affiliation: Guy's and St Thomas' Hospital, London, 1st Floor, Bermondsey Wing, Guy's Hospital, Great Maze Pond, London SE1 9RT, UK.
authors.forename: W
authors.initials: W
authors.lastname: Dandachli
authors.affiliation: Southampton University Hospitals NHS Trust, Tremona Road, Southampton SO16 6YD, UK.
authors.forename: Z
authors.initials: Z
authors.lastname: Beech
authors.affiliation: Guy's and St Thomas' Hospital, London, 1st Floor, Bermondsey Wing, Guy's Hospital, Great Maze Pond, London SE1 9RT, UK.
authors.forename: M J
authors.initials: MJ
authors.lastname: Bankes
authors.affiliation: University College of London Hospitals, 235 Euston Road, London NW1 2BU, UK.
authors.forename: J D
authors.initials: JD
authors.lastname: Witt
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging / Q000601:surgery*; D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D016009:Chi-Square Distribution; D015331:Cohort Studies; D005188:False Negative Reactions; D005260:Female; D005500:Follow-Up Studies; D015775:Fractures, Stress / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000209:etiology*; D006801:Humans; D015994:Incidence; D007512:Ischium / Q000000981:diagnostic imaging; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D010027:Osteotomy / Q000009:adverse effects* / Q000379:methods*; D011183:Postoperative Complications / Q000000981:diagnostic imaging / Q000453:epidemiology; D011859:Radiography; D012189:Retrospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D017678:Sex Distribution; D055815:Young Adult
keywords: Peri-acetabular osteotomy; Stress fracture; Complication