Preoperative anterior coverage of the medial acetabulum can predict postoperative anterior coverage and range of motion after periacetabular osteotomy: a cohort study

Abstract

Background: We hypothesized that preoperative pelvic morphology may affect postoperative anterior coverage and postoperative clinical range of motion (ROM) leading to postoperative pincer type femoroacetabular impingement (FAI). The aim of this study was to evaluate the relationships between preoperative bone morphology and postoperative ROMs to prevent postoperative FAI after periacetabular osteotomy. Methods: Sixty-eight patients (71 hips) with hip dysplasia participated in this study and underwent curved PAO. The acetabular fragment was usually moved only by lateral rotation of the acetabulum, without intraoperative anterior or posterior rotation. The pre-and postoperative three-dimensional center-edge (CE) angles were measured and compared to the postoperative ROM. Results: Preoperative medial anterior CE angle was significantly associated with postoperative anterior CE angle, and the correlation coefficient of medial anterior CE and postoperative anterior CE was higher than the coefficient of preoperative anterior CE and postoperative anterior CE (preoperative anterior CE, rr = 0.27, p = 0.020; preoperative medial anterior CE, rr = 0.54, p < 0.001). Femoral anteversion correlated with postoperative internal rotation angle at 90°f lexion (r = 0.32, p = 0.021). In multiple linear regressions, postoperative internal rotation angle at 90°flexion angle was significantly affected by both medial CE angle through the medial one fourth of femoral head and femoral anteversion. Conclusions: Preoperative medial anterior acetabular coverage was associated with postoperative anterior acetabular coverage. Further, the combination with preoperative medial anterior acetabular coverage and femoral anteversion can predict postoperative internal rotation at 90°flexion. Therefore, the direction of acetabular reorientation should be carefully considered when the patients have high preoperative medial anterior CE angle and small femoral anteversion.

Anterior acetabular coverage and femoral head–neck measurements predict postoperative anterior impingement: A simulation study

“…In conclusion, the current ROM simulation study demonstrated that a combined anteversion <48°, anterior CE angle ≥62°, and combination angle ≥108° are predictive factors for the occurrence of postoperative anterior impingement after curved PAO, and that combination angle values of <108° are significantly associated with excellent clinical results. When we focused on the preoperative combination angle, we previously reported that the mean acetabular anterior CE angle was increased by around 19°, from 43.2° to 62.3°, increasing the combination angle by the same amount after PAO 12,23 . The current study demonstrated that the postoperative anterior CE angle + α angle ≥108° caused postoperative anterior impingement.…”

“…When we focused on the preoperative combination angle, we previously reported that the mean acetabular anterior CE angle was increased by around 19°, from 43.2°to 62.3°, increasing the combination angle by the same amount after PAO. 12,23 The current study demonstrated that the postoperative anterior CE angle + α angle ≥108°caused postoperative anterior impingement.…”

“…Femoral anteversion was defined according to a previous report. 23 Briefly, the femoral neck axis was calculated as the line of best-fit connecting slices drawn through a central segment of the neck. Canal anteversion was defined as the angle between the axis of the neck and the segment connected to the epicondylar line.…”

Overcorrection of the acetabular roof angle or anterior center–edge angle may cause decrease of range of motion after curved periacetabular osteotomy

“…We previously reported the univariate analysis of post-operative ROMs and total anteversion of the acetabular and femoral sides and demonstrated that flexion and internal rotation were associated with total anteversion [ 17 ]. Our present study also demonstrated similar results, as seen on the univariate analysis ( Table II ).…”

“…Therefore, we also measured radiographic parameters by using 3D reconstruction CT data to analyze the outcome of PAO. We recently discovered that the post-operative ROM of flexion and internal rotation were significantly associated with the post-operative 3D-anterior CE angles, and concluded that excessive anterior acetabular coverage caused a decrease in the ROM [ 17 ]. However, the relationship between radiographic parameters other than the anterior CE angle and post-operative ROM was still unclear.…”