Age and magnitude of acetabular correction impair bone healing after triple pelvic osteotomy

INTRODUCTION: The aim of this examination was to assess, which risk factors impair bone healing after triple pelvic osteotomy (TPO) in the treatment of symptomatic hip dysplasia. METHODS: A consecutive series of 241 TPO was reviewed retrospectively. Of these, a set of five postoperative radiographs was available, performed in a standardized regimen in the first year after surgery. Two experienced observers had to agree on the existence of a non-union on the radiographs obtained 1 year after TPO. Both observers measured the lateral center edge angle (LCEA) and acetabular index (AI) on all radiographs. Besides patient-specific risk factors, the magnitudes of acetabular correction and the amounts of a detectable slight change in acetabular correction were assessed. Binary logistic regression analysis and chi-squared test were used to detect the impact of the risk factor on bone healing. RESULTS: A total of 222 cases were left for further examination. In 19 of these, at least one osteotomy was not healed completely one year after surgery. Binary logistic regression showed a significant relationship between the risk factors “age” (p < 0.001; odds ratio (OR) 1.109 (95% CI 1.05–1.18)) as well as “magnitude of acetabular correction (LCEA)” (p = 0.01; OR 1.087 (95% CI 1.02–1.16)) and non-union. Pearson’s chi-square test showed a relationship between the risk factor “wound healing disorder” and non-union (p < 0.001). LCEA and AI showed a slight increase from the first to the last follow-up (observer 1: 1.6° and 1.3°, resp.), but regression analysis for the risk factor “amount of postoperative change of acetabular correction (LCEA, AI)” did not show statistically significant values. CONCLUSION: The age at surgery and the magnitude of acetabular correction negatively influenced the healing progress of the osteotomy sites. The amount of a slight postoperative change of LCEA and AI did not correlate with a non-union.