Screw fixation after tripe pelvic osteotomy is reliable: changes of acetabular correction are rare and do not correlate with risk factors

Purpose: The aim of this examination was to assess whether there is a change of acetabular correction after triple pelvic osteotomy (TPO) and if so, whether there is a correlation with patient-specific risk factors or with certain periods in the postoperative course.

Methods: A consecutive series of 241 TPO was reviewed retrospectively. The close-meshed radiographic follow-up of the first 12 weeks comprised pelvic radiographs performed immediately after the procedure, 5 days, 6 and 12 weeks after TPO. Three observers measured the lateral center edge angle, acetabular index and the craniocaudal offset of the pubic osteotomy. Patient-specific risk factors (e. g. age, gender, body mass index, nicotine abuse) and certain periods in the postoperative course were correlated with a change of acetabular correction.

Results: After application of the exclusion criteria, 225 hips were available for further examination. Intraclass correlation coefficient resulted in predominantly excellent agreement between the measurements of the three observers (0.74-0.91). In 27 cases (12%), the three observers agreed on a change of acetabular correction. In 18 cases (8%), there was a slight change, in 9 cases (4%), a relevant change. The latter entailed consequences in the postoperative aftercare. General equation estimation did not show any correlation between a change of acetabular correction and patient-specific risk factors or certain periods in the postoperative course (p = 0.79-0.99).

Conclusion: Every once treated hip should be followed-up with the same attention, irrespective of the apparent risk profile. There is no rationale to skip a radiographic follow-up in the first 12 weeks after TPO.