Reinhold Ganz’s research while affiliated with University of Bern and other places

The extended retinacular flap is a subsequent development of the surgical hip dislocation approach. It is based on a technique of Dunn, proposed 60 years ago, for open reduction of severe slips. The extension, as described in this chapter, further reduces the risk of avascular necrosis of the femoral head and is the condition for several new intraarticular procedures. The chapter describes indications, surgical steps, and technical risks in detail.

Capsular arthroplasty of the hip was abandoned for decades until better understanding of the vascular supply to the hip region and consequent intracapsular procedures allowed reconsideration. Safe surgical hip dislocation (SHD), observance of the capsular blood supply, and dissection of the retinacular flap guaranteed optimal quality of the capsular coverage. Shelf acetabular augmentation, relative lengthening of the neck, reduction of femoral head size, as well as femoral shortening and derotation increased the spectrum of indications and helped increase the pelvi-femoral clearance and avoid femoral head necrosis and stiffness. The capsular arthroplasty is a procedure used to treat congenital hip dislocation by wrapping the capsule around the femoral head and relocating it into a newly reamed anatomically located acetabulum. By interposing capsule, like in the Chiari and shelf procedures, load transmission induces metaplasia of the interposed capsular tissue to fibrous cartilage. When properly selected and executed, such hips can last for decades, function well, and facilitate a routine total hip replacement at an appropriate age. Subsequent to the original technique description, the decreasing prevalence of severe developmental dysplasia of the hip (DDH), in addition to historically high rate of complications like stiffness, necrosis, and the need for early revision, led to the near abandonment of the Colonna following the introduction of total hip arthroplasty (THA). This chapter describes indications, surgical technique, and complications and concludes with a summary of results.

The indication for upper intertrochanteric (ITO) and subtrochanteric (STO) femoral osteotomies is becoming less frequent due to the favourable results of total hip replacements even when implanted in rather young adults. In contrast to total hip arthroplasty (THA), the outcome of hip osteotomies can be unpredictable, especially when performed for established osteoarthritis. In addition to this, classic hip osteotomies are burdened with undesired side effects including limb shortening, abductor weakness, extra-articular impingement, local pain from hardware, and more complicated conversion to THA. Using the rather safe surgical hip dislocation (SHD) and the extended retinacular flap technique, the femoral neck area can be approached without interfering with the femoral head perfusion. The osteotomy level can be moved closer to the joint, avoiding or minimizing most side effects of intertrochanteric or subtrochanteric osteotomies. Current indications to perform a femoral neck osteotomy (FNO) include severe valgus deformities, deformities resulting from slipped capital femur epiphysis (SCFE), irregularities of the head contour and post-traumatic deformities. In some complex morphologies, it can be combined with a periacetabular osteotomy (PAO). True femoral neck osteotomy (FNO) is the surgical technique that enables intra-articular corrections at the level of the femoral neck. It can be performed using the surgical hip dislocation and the extended retinacular techniques (see Chaps. 7 and 8). It allows for a larger correction when compared to more distal osteotomies (see Chap. 15) as the osteotomy line lies closer to the femoral head. In addition, adverse side correction effects such as limb shortening and secondary deformity affecting total hip arthroplasty are minimal. The extraordinary good results are faced with a demanding technique. The risk of complications such as avascular necrosis or delayed union is linked to inadequate indication, poor detailed knowledge of the vascular anatomy, imprecise surgical technique, and lack of experience.

Severe deformities of femoral head and acetabulum after Perthes disease or Perthes-like deformities are prone to early degeneration. Surgical procedures with extracapsular approach can hardly change this prognosis. Application of detailed vascular knowledge has enabled an extension of intracapsular surgery including segmental resection of the femoral head, allowing direct correction of the deformity. This chapter describes indications, technical execution, as well as possible risk factors and complications of the procedure. Finally, it gives an overview of results. The femoral head has an asymmetric dual blood supply, coming primarily from the deep branch of the medial femoral circumflex artery (MFCA) and from the medial branch of the MFCA, each vessel running in a retinacular fold, which can be mobilized from the neck bone. While the supply from the deep branch can perfuse the entire epiphysis, the medial branch perfuses approximately the medial half of the head. Based on this blood distribution, a portion of the central head can be resected without circulatory consequences for both remaining parts. Because the medial portion rests connected with the neck, this retinacular flap does not need to be mobilized. The lateral portion of the head/neck is mobilized after preparation of the lateral flap and becomes reduced against the stable medial portion and fixed with 2(−3) screws. The resected portion can be a parallel segment, or an anterior- or posterior-based wedge. The mobile lateral portion can be rotated, abducted or adducted, and/or shifted in a cephalad or caudad direction, all within the limits of the retinacular tension. Ideally, the “new” head is close to spherical and has the size of the opposite head.

Executing an extended retinacular flap containing the blood supply for the femoral head, reduction osteotomy (FHO) can be performed, increasing the potential of correction of complex hip morphologies. The aim of this study was to analyse the safety of the procedure and report the clinical and radiographic results in skeletally mature patients with a minimum follow up of two years. Twelve symptomatic patients (12 hips) with a mean age of 17 years underwent FHO using surgical hip dislocation and an extended soft tissue flap. Radiographs and magnetic resonance imaging producing radial cuts (MRI) were obtained before surgery and radiographs after surgery to evaluate articular congruency, cartilage damage and morphologic parameters. Clinical functional evaluation was done using the Non-Arthritic Hip Score (NAHS), the Hip Outcome Score (HOS), and the modified Harris Hip Score (mHHS). After surgery, at the latest follow-up no symptomatic avascular necrosis was observed and all osteotomies healed without complications. Femoral head size index improved from 120 ± 10% to 100 ± 10% (p<0,05). Femoral head sphericity index improved from 71 ± 10% before surgery to 91 ± 7% after surgery (p<0,05). Femoral head extrusion index improved from 37 ± 17% to 5 ± 6% (p< 0,05). Twenty five percent of patients had an intact Shenton line before surgery. After surgery this percentage was 75% (p<0,05). The NAHS score improved from a mean of 41 ± 18 to 69 ± 9 points after surgery (p< 0,05). The HOS score improve from 56 ± 24 to 83 ± 17 points after surgery (p< 0,05) and the mHHS score improved from 46 ± 15 before surgery to 76 ± 13 points after surgery (p< 0,05). In this series, femoral head osteotomy could be considered as safe procedure with considerable potential to correct hip deformities and improve patients reported outcome measures (PROMS). Level of evidence - Level IV, therapeutic study Keywords - Femoral head osteotomy, Perthes disease, acetabular dysplasia, coxa plana

The development of the Bernese periacetabular osteotomy (PAO) is based on a structured approach starting with an analysis of the preexisting procedures to improve the coverage of the femoral head and was followed by a list of additional goals and improvements. Cadaveric dissections with a detailed description of the vascular supply of acetabulum and periacetabular bone set the stage for an intrapelvic approach, which offered the largest acetabular correction possible combined with safe intracapsular access. The final composition of osteotomies required the development of several instruments and cutting devices before the feasibility could be tested on a series of cadaveric hips. While the sequence of the osteotomies remained largely unchanged over time (except for the pubic and ischial osteotomies), several propositions for an easier/less invasive approach have been discussed; some made it into standard practice. Efforts were undertaken to optimize the learning curve and minimize failures using video-clips, hands-on courses, fellowships, publications, and ongoing mentoring programs. In retrospect, with almost 40 years of experience, such efforts have promoted a worldwide adoption of the Bernese periacetabular osteotomy.

The present study aimed to investigate the clinical results of the modified Codivilla–Hey Groves–Colonna capsular arthroplasty in the treatment of young patients with developmental dislocation of the hip. We retrospectively evaluated 90 patients (92 hips) who underwent the modified capsular arthroplasty from June 2012 to June 2021. Hips were evaluated using the modified hip Harris score (mHHS), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score and the 12-item International Hip Outcome Tool (iHOT-12). The Tönnis osteoarthritis grade and the Severin classification system were used to assess the radiographic outcomes. The average age was 15.7 years (range: 8–26 years). The mean pre-operative mHHS, the WOMAC score and the iHOT-12 score were 83.03, 14.05 and 52.79, respectively. The patients were followed for a mean of 41.1 months (range: 12.1–120.9 months). The patients had a mean mHHS of 83.61 (range: 31.2–97), a WOMAC score of 16.41 (range: 0–51) and an iHOT-12 score of 64.81 (range: 12.9–98.2) at the final follow-up. Capsular thickness had a positive predication on the final functional outcomes. The excellent/good rate of radiological reduction was 79.3%. More than 60% of patients had no/slight osteoarthritis. A total of 54 hips (58.7%) had superior radiographic outcomes. The risk factors for inferior radiographic outcomes were capsular quality (odds ratio [OR]: 0.358, 95% confidence interval [CI]: 0.113–0.931) and capsular thickness (OR: 0.265, 95% CI: 0.134–0.525). Joint stiffness was the most common complication (14.1%). We confirmed the efficacy of this procedure in the treatment of developmental hip dislocation. Patients with poor capsular quality are not suitable for this procedure. With suitable selection according to indications, this procedure can restore the hip rotation center with a low incidence of femoral head necrosis or severe osteoarthritis.

Aims: Avascular femoral head necrosis in the context of gymnastics is a rare but serious complication, appearing similar to Perthes' disease but occurring later during adolescence. Based on 3D CT animations, we propose repetitive impact between the main supplying vessels on the posterolateral femoral neck and the posterior acetabular wall in hyperextension and external rotation as a possible cause of direct vascular damage, and subsequent femoral head necrosis in three adolescent female gymnasts we are reporting on. Methods: Outcome of hip-preserving head reduction osteotomy combined with periacetabular osteotomy was good in one and moderate in the other up to three years after surgery; based on the pronounced hip destruction, the third received initially a total hip arthroplasty. Results: The described pathology is quite devastating, and extensive joint preserving surgery (which has been shown successful in Perthes' cases) was less successful in this patient cohort. Conclusion: Supraselective angiography may be helpful to improve pathomechanical understanding and surgical decision making.Cite this article: Bone Jt Open 2022;3(9):666-673.