Dynamic hip kinematics before and after periacetabular osteotomy in patients with dysplasia

Abstract

Background: We prospectively analyzed the hip kinematics in patients with developmental dysplasia of the hip (DDH) before and after periacetabular osteotomy (PAO) and in healthy subjects while squatting to determine the influence of coverage of the femoral head on hip kinematics. Methods: 14 hips in 14 patients with DDH and 10 hips in 10 volunteers were included. Continuous radiographs while squatting and computed tomography images were obtained to assess the in vivo kinematics of the hip and the rim-neck distance using density-based 3D-to-2D model-to-image registration techniques. Results: The maximum hip flexion angles were 100.4 and 94.9 before and after PAO (p ¼ 0.0863), respectively. The maximum hip flexion angles after PAO did not significantly differ from those of normal hips (102.2 ; p ¼ 0.2552). The hip abduction angles at maximum hip flexion were 31.7 and 26.2 before and after PAO (p ¼ 0.1256), respectively. The rim-neck distance decreased from averaged 12.2 mm e8.9 mm (p ¼ 0.0044) after PAO. The lateral center edge angle (LCEA) and anterior center edge angle (ACEA) significantly improved 14.7 e42.4 and 50.4 e54.0 after PAO (p < 0.0001, p ¼ 0.0347), respectively; in particular, the ACEA after PAO did not significantly differ from that in the normal hips (p ¼ 0.1917). The ACEA was not correlated with hip flexion, or the rim-neck distance (p ¼ 0.9601, 0.8764). The LCEA was also not correlated with hip abduction (p ¼ 0.1683). Conclusion: Patients after PAO showed no significant difference in maximum hip flexion while squatting compared to before PAO and normal hips. Horizontalized weight-bearing acetabulum with normalized ACEA could be adequate correction of the acetabular fragment to restore hip RoM without coxalgia that induce the inability to perform squats after PAO.

Component rotational mismatch in the standing position is a potential risk factor for unfavourable functional outcomes after total knee arthroplasty

“…Therefore, the present study utilized a 3D‐to‐2D model image registration technique to measure rotational alignment from radiographs taken in both the supine and standing positions. This technique has been previously used to analyse hip and knee joint kinetics using fluoroscopic images of daily activities, such as walking and squatting, demonstrating its high accuracy [ 9 , 25 , 46 ]. It has recently been applied to assess changes in axial alignment between the supine and standing positions in patients after total hip arthroplasty [ 42 ] or the intraoperative acetabular component in total hip arthroplasty [ 15 ].…”

Capsular Mechanics After Periacetabular Osteotomy for Hip Dysplasia

“…The computational bone collision simulations in the study by Steppacher et al likewise demonstrated that PAO restored abduction-adduction motions, but that study differed in that it showed a change in abduction (from 88 ± 4° to 57 ± 14°, p < 0.001) that was larger than the change in adduction (from 41 ± 13° to 48 ± 14°, p = 0.029) only in the neutral position 39 . Yoshimoto et al recently analyzed squatting kinematics in patients with dysplasia after treatment with PAO using in vivo image registration, showing reduced flexion and abduction postoperatively 46 . Overall, the difference between the changes in abduction and adduction range of motion in the present study suggests that the capsule plays a role in stabilizing the hip and protecting against edge loading.…”