Mean 20-year followup of Bernese periacetabular osteotomy

Abstract

The goal of the Bernese periacetabular osteotomy is to correct the deficient acetabular coverage in hips with developmental dysplasia to prevent secondary osteoarthrosis. We determined the 20-year survivorship of symptomatic patients treated with this procedure, determined the clinical and radiographic outcomes of the surviving hips, and identified factors predicting poor outcome. We retrospectively evaluated the first 63 patients (75 hips) who underwent periacetabular osteotomy at the institution where this technique was developed. The mean age of the patients at surgery was 29 years (range, 13-56 years), and preoperatively 24% presented with advanced grades of osteoarthritis. Four patients (five hips) were lost to followup and one patient (two hips) died. The remaining 58 patients (68 hips) were followed for a minimum of 19 years (mean, 20.4 years; range, 19-23 years) and 41 hips (60%) were preserved at last followup. The overall mean Merle d'Aubigné and Postel score decreased in comparison to the 10-year value and was similar to the preoperative score. We observed no major changes in any of the radiographic parameters during the 20-year postoperative period except the osteoarthritis score. We identified six factors predicting poor outcome: age at surgery, preoperative Merle d'Aubigné and Postel score, positive anterior impingement test, limp, osteoarthrosis grade, and the postoperative extrusion index. Periacetabular osteotomy is an effective technique for treating symptomatic developmental dysplasia of the hip and can maintain the natural hip at least 19 years in selected patients.

Level of evidence: Level III, prognostic study.

Fig. 1A–C

The Bernese periacetabular osteotomy is performed through a modified Smith-Petersen approach, including an osteotomy of the anterior superior iliac spine to dissect the inguinal ligament and the adjacent muscles. (A) With four periacetabular osteotomies and a controlled fracture, the acetabulum is completely mobilized from the innominate bone. (B) For fixation of the reoriented fragment, three cortical screws are used. (C) The posterior column of the true pelvis remains intact maintaining stability through an intact continuity of the pelvic ring.

Fig. 2

The Kaplan-Meier survival analysis is shown with the conversion to a THA or hip fusion as the end points. Values are expressed as cumulative survivorship with 95% confidence interval in parentheses for each 5-year interval. Circles indicate censored data.

Fig. 3A–G

Radiographs are shown of a 26-year-old woman with a dysplastic right hip with (A) an LCE angle of 16° and an AI of 12° without any signs of osteoarthritis (Tönnis osteoarthritis Grade 0 [55]). Initially she presented with limping and a negative impingement test. The mean Merle d’Aubigné and Postel score was 15. (B) The postoperative LCE angle was 32° and the AI −2°. At the (C) 10-year and the (D) 20-year followups, no osteoarthitic changes were seen. At last followup, the mean Merle d’Aubigné and Postel was 17, limping disappeared, and the impingement test remained negative. (E) In the corresponding false-profile [24] views, (F) the preoperative ACE angle of 39° increased to 45° postoperatively and (G) no osteoarthritic changes were seen at the 10-year followup. LCE = lateral center edge angle; AI = acetabular index; ACE = anterior center edge angle.

Fig. 4A–G

Radiographs are shown of a 46-year-old women with a (A) dysplastic right hip with cranial acetabular retroversion, an LCE angle of 8°, an AI of 24°, and preoperative osteoarthritis grade of 1 according to Tönnis [55]. Initially she presented without limping and a negative impingement test. The mean Merle d’Aubigné and Postel score was 16 as a result of a decrease in pain status. (B) With the PAO, good coverage could be achieved with a postoperative relatively highly anteverted acetabular fragment and a resultant prominent posterior wall with an LCE angle of 30° and an AI angle of 4°. (C) The osteoarthritis showed marked progression after 5 years with end-stage osteoarthritis (Tönnis Grade 3), and (D) 10 years after the PAO, a THA with an acetabular reinforcement ring was performed. In the corresponding false-profile [24] views, the (E) preoperative ACE angle of 2° increased to (F) 25° postoperatively and showed (G) early deterioration with end-stage osteoarthritis at the 10-year followup. LCE = lateral center edge angle; AI = acetabular index; ACE = anterior center edge angle.

Fig. 5

This flowchart shows the distribution of osteoarthritis (OA) progression and the failure rate depending on the preoperative osteoarthritis score of all 68 evaluated hips.

Fig. 6A–C

The first Bernese PAO was performed in 1984 in a 13-year-old girl with a (A) subluxated femoral head articulating in a very shallow and retroverted acetabulum after proximal femoral focal deficiency. (B) The PAO was performed with a concomitant valgus intertrochanteric osteotomy. Three years later, progressive posterior subluxation in flexion resulting from a deficient posterior coverage made a posterior shelfplasty necessary. (C) Twenty-three years later, she presented with a good clinical result (Merle d’Aubigné and Postel score, 15).