The Scientific Evolution of Periacetabular Osteotomy: A Global Review

Unveiling the learning curve of periacetabular osteotomy

Aims

Periacetabular osteotomy (PAO) is widely recognized as a demanding surgical procedure for acetabular reorientation. Reports about the learning curve have primarily focused on complication rates during the initial learning phase. Therefore, our aim was to assess the PAO learning curve from an analytical perspective by determining the number of PAOs required for the duration of surgery to plateau and the accuracy to improve.

Methods

The study included 118 consecutive PAOs in 106 patients. Of these, 28 were male (23.7%) and 90 were female (76.3%). The primary endpoint was surgical time. Secondary outcome measures included radiological parameters. Cumulative summation analysis was used to determine changes in surgical duration. A multivariate linear regression model was used to identify independent factors influencing surgical time.

Results

The learning curve in this series was 26 PAOs in a period of six months. After 26 PAO procedures, a significant drop in surgical time was observed and a plateau was also achieved. The mean duration of surgery during the learning curve was 103.8 minutes (SD 33.2), and 69.7 minutes (SD 18.6) thereafter (p < 0.001). Radiological correction of acetabular retroversion showed a significant improvement after having performed a total of 93 PAOs, including anteverting PAOs on 35 hips with a retroverted acetabular morphology (p = 0.005). Several factors were identified as independent variables influencing duration of surgery, including patient weight (β = 0.5 (95% confidence interval (CI) 0.2 to 0.7); p < 0.001), learning curve procedure phase of 26 procedures (β = 34.0 (95% CI 24.3 to 43.8); p < 0.001), and the degree of lateral correction expressed as the change in the lateral centre-edge angle (β = 0.7 (95% CI 0.001 to 1.3); p = 0.048).

Conclusion

The learning curve for PAO surgery requires extensive surgical training at a high-volume centre, with a minimum of 50 PAOs per surgeon per year. This study defined a cut-off value of 26 PAO procedures, after which a significant drop in surgical duration occurred. Furthermore, it was observed that a retroverted morphology of the acetabulum required a greater number of procedures to acquire proficiency in consistently eliminating the crossover sign. These findings are relevant for fellows and fellowship programme directors in establishing the extent of training required to impart competence in PAO.

Making the cut: a technical note and literature review of Bernese periacetabular osteotomy techniques with special attention to ischial osteotomy initiation and completion with an inside to anterior curved osteotomy

Periacetabular osteotomy includes a fluoroscopy-guided ischial cut without direct visualization. Previously described techniques include a mediolateral ischial cortex cut, which is associated with the risk of injuring nearby nerves. Another drawback of that technique is the difficulty connecting an ischial cortex cut with a retroacetabular cut due to orthogonal nature of the osteotomy. In general, an additional cut from medial to lateral is required. The present study aimed to describe a technique that eliminates those problems due to use of only a central cut of the ischium and the curved nature of the osteotomy.

A bibliometric analysis and visualization of research trends on periacetabular osteotomy

Bernese periacetabular osteotomy (PAO) is a practical and safe acetabular reorientation technique used to correct structural hip deformities, and much relevant literature has been published over the past decades. This bibliometric study aims to determine the status of PAO research between 1994 and 2022. Information about PAO research publications from 1994 to 2022 was obtained from the Web of Science Core Collection. This bibliometric study is implemented and analyzed through three bibliometric tools with respect to publication counts, countries, institutions, authors, journals, funding agencies, references and keywords. In total, 634 publications concerning PAO were identified. The United States and Washington University in St. Louis have published the most literature in terms of country and institution. Additionally, Switzerland and the University of Bern are the country and the institution with the highest average number of citations in the PAO field. The most published and co-cited journal is Clinical Orthopaedics and Related Research. Burst keyword detection has discovered that 'patient-reported outcome', 'instability', 'risk', 'survivorship' and 'outcome' are regarded as the current research frontier. In summary, our findings provide insight into the bibliometric overview of research status in the PAO field, which may offer later investigators' references in exploring further research directions.

Effects of different pelvic osteotomies on acetabular morphology in developmental dysplasia of hip in children

Developmental dysplasia of hip seriously affects the health of children, and pelvic osteotomy is an important part of surgical treatment. Improving the shape of the acetabulum, preventing or delaying the progression of osteoarthritis is the ultimate goal of pelvic osteotomies. Re-directional osteotomies, reshaping osteotomies and salvage osteotomies are the three most common types of pelvic osteotomy. The influence of different pelvic osteotomy on acetabular morphology is different, and the acetabular morphology after osteotomy is closely related to the prognosis of the patients. But there lacks comparison of acetabular morphology between different pelvic osteotomies, on the basis of retrospective analysis and measurable imaging indicators, this study predicted the acetabular shape after developmental dysplasia of the hip pelvic osteotomy in order to help clinicians make reasonable and correct decisions and improve the planning and performance of pelvic osteotomy.

Periacetabular osteotomy for Tönnis grade 2 osteoarthritis secondary to hip dysplasia

PURPOSE

To investigate the clinical outcomes of periacetabular osteotomy (PAO) for Tönnis grade 2 osteoarthritis secondary to hip dysplasia.

METHODS

Forty-nine patients (51 hips) with Tönnis grade 2 osteoarthritis secondary to hip dysplasia, followed by a mean of 52.3 months (range: 24.1 to 95.2 months), were reviewed. As a control group, 51 patients (51 hips) with Tönnis grade 1 osteoarthritis were matched for age, surgery date, and follow-up period. All patients were evaluated clinically with the use of modified Harris hip score (mHHS) questionnaire, WOMAC score, and the 12-item International Hip Outcome Tool (iHot-12). Radiographic measurements included the lateral centre-edge angle (LCEA), Tönnis angle, and anterior centre-edge angle (ACEA). Kaplan-Meier survivorship analysis was performed to predict a five year survival rate of no osteoarthritis progression.

RESULTS

All functional scores and radiographic measurements of the two groups significantly improved at the final follow-up. There were no significant differences between the two groups either in functional scores or radiographic measurements. The five year survival rate of no osteoarthritis progression was 86.2% in Tönnis grade 2 group and 93.1% in Tönnis grade 1 group, respectively. In the Tönnis grade 2 group, the osteoarthritis progressed in six hips. Of which, four hips had an ACEA of < 25°. No osteoarthritis progression was found in hips with an ACEA > 40°.

CONCLUSIONS

PAO yielded similar results for patients with Tönnis grade 2 and grade 1 osteoarthritis secondary to hip dysplasia. The majority of hips can be preserved without progression of osteoarthritis at five years postoperatively. The slight overcorrection anteriorly may be helpful in preventing osteoarthritis progression.

Fifty percent of patients undergoing periacetabular osteotomy for hip dysplasia showed normal findings upon neonatal ultrasound screening : Symptomatic hip dysplasia in adulthood despite inconspicuous neonatal hip ultrasound

Developmental dysplasia of the hip (DDH) is characterized by the pathomorphology of inadequate acetabular coverage of the femoral head leading to increased loading of the articular surface and acetabular rim. If left untreated, this ultimately leads to osteoarthritis. Germany introduced a nationwide universal ultrasound screening program for all newborn infants in 1996. Subsequently, the incidence of undiagnosed hip dislocation was significantly reduced. In this consecutive series of patients who underwent periacetabular osteotomy for the treatment of symptomatic dysplasia of the hip between October 2014 and October 2022 data regarding the U3 screening examination were analyzed. The data included whether the examination was performed, whether the findings were positive or negative, whether the patients underwent any form of treatment in the case of a positive finding and whether a control X‑ray was performed. This study provides evidence that acetabular undercoverage cannot be ruled out based on a normal finding in ultrasonography screening. Furthermore, the study also shows that residual dysplasia may persist despite attempts of conservative treatment.