Original Bernese PAO proved effective for treatment of hip dysplasia

A retrospective study determined 43% of patients who underwent this type of osteotomy 30 years ago were not converted to total hip arthroplasty.

Issue: March 2016

The prevalence of a positive anterior impingement test and limp declined at 30-year follow-up among patients who underwent some of the first Bernese periacetabular osteotomies performed for the treatment of symptomatic developmental dysplasia of the hip, based on results of a retrospective study.

Till D. Lerch, MD, research assistant in the Department of Orthopaedic Surgery and Traumatology, University of Bern, in Bern, Switzerland, is scheduled to present the study findings during a hip osteotomy session at the 17th EFORT Annual Congress in Geneva in June.

Long-term success reported

Patients who underwent a Bernese periacetabular osteotomy (PAO) and had a surviving hip at the 30-year follow-up had Merle d’Aubigne-Postel scores of about 16, which were significantly higher than their scores at the 10-year and 20-year follow-up.

Hip dysplasia without osteoarthritis — A 26-year old woman (left) presented with hip pain due to hip dysplasia without osteoarthritis (OA). A Bernese periacetabular osteotomy was performed to improve acetabular coverage. The re-oriented acetabular fragment was fixed with two screws (center). At the 30-year follow-up, the patient presented with no hip pain, a good functioning hip and no signs of OA (right).

“At the 30-year follow-up, 29% of the first 75 hips undergoing the Bernese periacetabular osteotomy had not converted to total hip arthroplasty, showed no progression of osteoarthritis and had a good clinical result. Key factors for successful outcome were a young patient age, no or little osteoarthritis and preoperative good hip function with only little pain. These results reflect the learning curve and first experience of a new surgical technique,” Lerch told Orthopaedics Today Europe.

The retrospective study included the first 63 patients (75 hips) to undergo a Bernese PAO. The patients were operated on by the originator of the procedure Reinhold Ganz, MD, in Bern between 1984 and 1987 at the investigator’s institution. In total, 24% of the patients presented preoperatively with advanced grades of osteoarthritis (OA) and 31% had previous surgery to improve acetabular coverage.

Positive clinical results

Investigators calculated the cumulative survivorship of the hips with a Kaplan-Meier estimate in which conversion to a total hip arthroplasty (THA), progression of OA or a poor clinical outcome were the endpoints. They also assessed patients with the Harris Hip score and identified radiographic progression of OA according to Tönnis grade in the surviving hips.

At 30-year follow-up, 57% of the hips were converted to THA; 5% showed progression of OA; and 4% had a poor clinical outcome. This resulted in a cumulative survivorship of 29%.

In addition, the prevalence of limp decreased from 66% to 18%, and the prevalence of pain in flexion/internal rotation decreased from 40% to 14% at final follow-up.

“This is a heterogeneous group and at the beginning of a learning curve of a new surgical technique. Compared to more recent series of patients, the survivor rate is less than what you would expect from today’s operation. The indications have gotten more precise. Since the first case in 1984, more than 1,000 PAOs have been performed at our institution. In this historic series, we had patients with advanced OA where nowadays we would never operate on them. Although this heterogeneity reduced the overall survivorship, these variations allowed analysis of key factors predicting long-term survival,” coauthor Simon D. Steppacher, MD, told Orthopaedics Today Europe.

These factors likely reduced the 30-year survival, but long-term survival with current Bernese PAO indications can be expected to be higher, according to Lerch. – by Robert Linnehan

Reference:
Lerch T, et al. Paper #2644. Tentatively scheduled to be presented 1 June, 15:30-16:30, at: 17th EFORT Annual Congress – a combined programme in partnership with swiss orthopaedics; 1-3 June 2016; Geneva.

For more information:
Till D. Lerch, MD, can be reached at Department of Orthopaedic Surgery and Traumatology, University of Bern, Inselspital Bern, 3010 Bern, Switzerland; email: till.lerch@insel.ch.
Simon D. Steppacher, MD, can be reached at Department of Orthopaedic Surgery and Traumatology, University of Bern, Inselspital Bern, 3010 Bern, Switzerland; email: simon.steppacher@insel.ch.

Disclosures: Lerch and Steppacher report no relevant financial disclosures.