Does pelvic tilt change with a peri-acetabular osteotomy?

Area of Science:

• Orthopedic surgery
• Hip dysplasia treatment
• Radiographic analysis

Background:

• Pelvic tilt (PT) is a critical factor in surgical planning for peri-acetabular osteotomy (PAO).
• Understanding PT variations during and after PAO is essential for optimizing patient outcomes.
• Previous studies have not fully elucidated the dynamic changes in PT throughout the PAO treatment course.

Purpose of the Study:

• To investigate the variability of pelvic tilt (PT) during and after peri-acetabular osteotomy (PAO).
• To identify factors influencing PT changes following PAO.
• To assess the impact of PT alterations on the achievement of optimal acetabular correction.

Main Methods:

• Retrospective analysis of 111 consecutive patients undergoing PAO for hip dysplasia.
• Pelvic tilt (PT) was measured using the sacro-femoral-pubic (SFP) angle on radiographs at multiple time points: pre-operatively, intra-operatively, 1-day, 6-weeks, and 1-year post-operatively.
• Optimal acetabular correction was defined by specific ranges for the lateral centre-edge angle, acetabular index, and cross-over ratio.

Main Results:

• A statistically significant difference in SFP angle was observed between pre-operative and 1-day/early post-operative measurements (P < 0.001 and P = 0.004, respectively).
• The difference in SFP angle between pre-operative and 1-year post-operative measurements was minimal (-0.5° ± 3.1°, P = 0.043), with only 9% of cases showing a change >5°.
• No significant correlation was found between PT changes and patient demographics (age, sex, BMI), dysplasia type, or the achievement of optimal acetabular correction.

Conclusions:

• Pelvic tilt (PT) demonstrates a transient reduction in the early post-operative period after PAO, which typically resolves by the 1-year follow-up.
• The degree of PT change during PAO does not appear to adversely affect fragment orientation or the achievement of surgical goals.
• Pelvic tilt (PT) does not significantly change in most patients undergoing PAO and is unlikely to be a primary compensatory mechanism.