Hip dysplasia—the Bernese contribution continues

March 2024 marked the 40th anniversary of the first Bernese periacetabular osteotomy (PAO) undertaken by Reinhold Ganz and Jeffrey Mast; on a 13-year-old girl with a proximal femoral focal deficiency and complex hip deformity [1]. It was a further 4 years before the first publication of this technique [2]. Over the past four decades, the superiority of the Bernese PAO over acetabular augmentation [3–5], single osteotomies [6–8], double osteotomies [9, 10] and triple osteotomies [11–13] has enabled tens of thousands of young people to enjoy active lives and delayed or prevented their need for hip arthroplasty. Throughout our careers, we adapt and refine our practice. We adopt interventions that are demonstrated to provide superior outcomes in peer-reviewed publications, and we abandon interventions that have been superseded by better alternatives. However, it can take decades to demonstrate true superiority of one treatment over another and the best intervention for a particular individual may not be clear-cut. Selection of appropriate patients for PAO and the provision of advice on the potential requirement for further surgery are examples of such uncertainty. While every patient is unique, knowledge of trends in care can be helpful to guide our decision-making and the opinions that we provide. In this issue, Stephen Bigach and the team at Northwestern University in Chicago, IL [14] provide a snapshot of the relative frequency that PAO is currently undertaken for men and women whose data can be accessed through the US PearlDiver database [15]. The authors provide a snapshot of the relative frequency that PAO is used for individuals of differing maturity, the incidence of such interventions per head of population, the frequency of interventions for associated intra-articular pathology or residual impingement, both concomitant with PAO and at a later date and the incidence of secondary interventions for removal of metalware. While the incidence of dysplasia requiring PAO surgery will vary in different geographic regions, this paper provides both PAO and non-PAO surgeons with information that will help them set patient expectations. It will also help PAO specialists to benchmark their own practices. One of the questions that exercise patients considering PAO surgery is their prospect of returning to sporting activity. Patients want to know what level of activity they could anticipate undertaking and how quickly this could be achieved. PAO surgeons need to weigh up their prospects for achieving the desired outcome through isolated PAO surgery against the potential benefit of concomitant hip arthroscopy (HA) for intra-articular pathology or impingement. Also, the additional down-time if a second intervention becomes necessary to address residual symptomatic impingement. Phillip Wyatt and the team from the Virginia Commonwealth University in Richmond, Virginia [16] provide us with a systematic review demonstrating that there is a growing body of literature to answer these questions. However, they conclude that there is still a paucity of work that allows us to discern what combination of pre-operative dysplasia and intra-articular pathology is best served by combined PAO with concomitant HA. While there is no longer debate as to whether concomitant PAO and HA can be undertaken safely, it will be some years before the literature is sufficiently mature for surgeons to advise their patients who would be best served by isolated PAO and who should be listed for PAO with HA. While acetabular dysplasia and its management have been extensively investigated over the past four decades, less attention has been paid to dysplasia of the proximal femur. Till Lerch and the team at the Inselspital, Bern University Hospital in Bern, have turned their attention to this problem and to the residual impingement that can occur after correction of decreased femoral anteversion. In their paper published in this issue [17], the Bernese team demonstrated that, as with changes in acetabular version, altering proximal femoral version can still leave residual impingement that requires concomitant correction. It is also noteworthy that the Bernese group favour plate fixation of their subtrochanteric osteotomies rather than the intramedullary nail technique that also has proponents [18]. It will be interesting to see which fixation technique gains the most support as the experience of this intervention grows over the next few decades. None declared.