Measure Subtrochanteric Osteotomy in Unilateral Crowe-IV Dysplasia-Surgical Technique.

Objective: Determining the optimal osteotomy length for patients with unilateral Crowe-IV developmental dysplasia of the hip undergoing subtrochanteric osteotomy remains challenging due to the significant variability in pelvic and spinal alignment. Incorrect osteotomy length, compounded by pelvic or spinal tilt, can adversely affect postoperative gait and long-term outcomes. Therefore, this study could introduce a method to calculate the osteotomy length for patients with unilateral Crowe-IV developmental dysplasia of the hip, correcting spinal and pelvic tilt, and improving patient gait.

Methods: This is a retrospective study that included 28 patients with unilateral Crowe-IV developmental dysplasia of the hip collected from June 2019 to June 2020, who underwent total hip arthroplasty with measured subtrochanteric osteotomy technique. The average follow-up period was 4.3 years (last follow-up). Harris scores, pelvic tilt angles represented by iliac obliquity angle (IO) and sacral obliquity angle (SO), and postoperative complications were recorded. Statistical analysis was performed using independent sample t-tests for normally distributed data and the Mann-Whitney U test for non-normally distributed data.

Results: Postoperatively, pelvic tilt angles improved significantly. The comparison of preoperative and postoperative 3-month IO angles (8.77° ± 3.31° vs. 5.28° ± 2.29°, p = 0.00), and postoperative 3-month and last follow-up (5.28° ± 2.29° vs. 2.88° ± 1.39°, p = 0.00) showed statistically significant differences. Similarly, the comparison of preoperative and postoperative 3-month SO angles (9.56° ± 3.1° vs. 5.81° ± 2.78°, p = 0.00), and postoperative 3-month and last follow-up (5.81 °± 2.78° vs. 3.59° ± 1.72°, p = 0.00) showed statistically significant differences. Harris scores significantly improved from preoperative to 1-year postoperative (47.35 ± 12.32 vs. 80.5 ± 7.81, p = 0.00), and from 1-year postoperative to last follow-up (80.5 ± 7.81 vs. 90.78 ± 2.86, p = 0.00) with statistical significance. There were no significant differences in adverse event rates between the two groups.

Conclusion: Total hip arthroplasty combined with measurement subtrochanteric osteotomy technique improves pelvic tilt and Harris scores in Crowe-IV developmental dysplasia patients. This technique may serve as a guideline for determining resection length.