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

Jens Goronzy,Albrecht Hartmann,Lea Franken,Sophia Blum,Falk Thielemann,Klaus-Peter Günther,Anne Postler,Jörg Nowotny

doi:10.1186/s12891-020-03878-y

Jens Goronzy, Albrecht Hartmann + Show 6 more

Open Access

https://doi.org/10.1186/s12891-020-03878-y

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Abstract

BackgroundPeriacetabular 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.MethodsA 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.ResultsAfter 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.ConclusionLong-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.

Highlights

Periacetabular osteotomy is a successful treatment for hip dysplasia
At our university center, isolated periacetabular osteotomy for hip dysplasia was performed on 106 hips (86 patients) from July 2005 to December 2010
Femoral torsion had a regular distribution for patients with dysplasia (Fig. 6)

Summary

Introduction

Periacetabular osteotomy is a successful treatment for hip dysplasia. Several mid- and long-term studies have shown periacetabular osteotomy (PAO) to be a successful treatment of hip dysplasia [1,2,3]. Increasing experience with this procedure and better understanding of hip pathomechanics helped defining a better patient selection and improved the procedure itself. The quality of the acetabular correction has an effect on the long-term survivorship. Further combined femoral and acetabular version may have an impact on pain and osteoarthritis progression. Some authors have described an association between abnormal combined anteversion and hip pain in unoperated patients [9]

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