Acetabular- and femoral orientation after periacetabular osteotomy as a predictor for outcome and osteoarthritis

Abstract

Background Periacetabular osteotomy is a successful treatment for hip dysplasia. The results are influenced, however, by optimal positioning of the acetabular fragment, femoral head morphology and maybe even femoral version as well as combined anteversion have an impact. In order to obtain better insight on fragment placement, postoperative acetabular orientation and femoral morphology were evaluated in a midterm follow-up in regard to functional outcome and osteoarthritis progression. Methods A follow-up examination with 49 prospectively documented patients (66 hips) after periacetabular osteotomy (PAO) was performed after 62.2 ± 18.6 months. Mean age of patients undergoing surgery was 26.7 ± 9.6 years, 40 (82%) of these patients were female. All patients were evaluated with an a.p. pelvic x-ray and an isotropic MRI in order to assess acetabular version, femoral head cover, alpha angle, femoral torsion and combined anteversion. The acetabular version was measured at the femoral head center as well as 0.5 cm below and 0.5 and 1 cm above the femoral head center and in addition seven modified acetabular sector angles were determined. Femoral torsion was assessed in an oblique view of the femoral neck. The combined acetabular and femoral version was calculated as well. To evaluate the clinical outcome the pre- and postoperative WOMAC score as well as postoperative Oxford Hip Score and Global Treatment Outcome were analyzed. Results After PAO acetabular version at the femoral head center (31.4 ± 9.6°) was increased, the anterior cover at the 15 o’clock position (34.7 ± 15.4°) was reduced and both correlated significantly with progression of osteoarthritis, although not with the functional outcome. Combined acetabular and femoral torsion had no influence on the progression of osteoarthritis or outcome scores. Conclusion Long-term results after PAO are dependent on good positioning of the acetabular fragment in all 3 planes. Next to a good lateral coverage a balanced horizontal alignment without iatrogenic pincer impingement due to acetabular retroversion, or insufficient coverage of the anterior femoral head is important.

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

“…However, research on the correlation between combined anteversion and postoperative clinical outcomes after PAO is rare. Goronzy et al reported that combined anteversion did not affect clinical outcome after PAO 32 . In fact, we demonstrated that the mean mHHS was not significantly different between patients with postoperative anterior impingement and nonimpingement because enough postoperative lateral coverage of the femoral head decreases the instability of the joint, and stabilization should favor pain relief after surgery.…”

“…Goronzy et al reported that combined anteversion did not affect clinical outcome after PAO. 32 In fact, we demonstrated that the mean mHHS was not significantly different between patients with postoperative anterior impingement and nonimpingement because enough postoperative lateral coverage of the femoral head decreases the instability of the joint, and stabilization should favor pain relief after surgery. These findings support our conclusion that combined anteversion values of <48°increase the risk of developing postoperative anterior impingement but do not affect postoperative clinical outcomes.…”

Intraoperative Fluoroscopy Allows the Reliable Assessment of Deformity Correction during Periacetabular Osteotomy

“…This results in an average change in the pelvic tilt of about 7 degrees in males and 14 degrees in females [ 21 ], also affecting the assessment of acetabular version [ 10 ]. Having reliable indices to comprehensively assess version helps to avoid retroversion and deviations of the anterior wall index, which are known to result in inferior postoperative outcomes [ 22 ], and to decrease the survival of native hip joints after PAO [ 23 ]. Therefore, besides meeting other well-recognized radiographic recommendations, the acetabular wall indices can eventually be determined intraoperatively to ascertain the desired adequate reorientation of the acetabular segment, with the aim to reduce the risk of a future conversion to total hip arthroplasty.…”

Dysplastic Hip Joint Configuration After Bernese Periacetabular Osteotomy

“…Goronzy et al assessed the predictors of coxarthrosis after PAO on the basis of AP Xray and MRI. The authors described that only posteriorly deformed femoral heads had an in uence on the functional outcome without alternating degeneration in the 5-year interval [18].…”

“…Bernese periacetabular osteotomy is one of the methods used to surgically "save" the patient's hip joint [4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19]. The procedure involves a periacetabular cut of the pubic, ischium, and ilium in an attempt to change the con guration of the joint socket and achieve the stability of the dysplastic hip joint.…”