Development of acetabular retroversion in LCPD hips-an observational radiographic study from early stage to healing.

BACKGROUND: Acetabular retroversion is observed frequently in healed Legg-Calvé-Perthes disease (LCPD). Currently, it is unknown at which stage and with what prevalence retroversion occurs because in non-ossified hips, retroversion cannot be measured with standard radiographic parameters. METHODS: In a retrospective, observational study; we examined pelvic radiographs in children with LCPD the time point of occurrence of acetabular retroversion and calculated predictive factors for retroversion. Between 2004 and 2017, we included 55 children with a mean age of 5.7 ± 2.4 years at diagnosis. The mean radiographic follow-up was 7.0 ± 4.4 years. We used two new radiographic parameters which allow assessment of acetabular version in non-ossified hips: the pelvic width index and the ilioischial angle. They are based on the fact that the pelvic morphology differs depending on the acetabular version. These parameters were compared among the four Waldenström stages and to the contralateral side. Logistic regression analysis was performed to determine predictive factors for acetabular retroversion. RESULTS: Both parameters differed significantly among the stages of Waldenström (p < 0.003 und 0.038, respectively). A more retroverted acetabulum was found in stage II and III (prevalence ranging from 54 to 56%) compared to stage I and IV (prevalence ranging from 23 to 39%). In hips of the contralateral side without LCPD, the prevalence of acetabular retroversion was 0% in all stages for both parameters. Predictive factors for retroversion were younger age at stage II and IV, collapse of the lateral pillar in stage II or a non-dysplastic hip. CONCLUSIONS: This is the first study evaluating acetabular version in children with LCPD from early stage to healing. In the developing hip, LCPD may result in acetabular retroversion and is most prevalent in the fragmentation (stage II) and early healing stage (stage III). Partial correction of acetabular retroversion can occur after healing. This has a potential clinical impact on the timing and type of surgical correction, especially in pelvic osteotomies for correction of acetabular version. LEVEL OF EVIDENCE: Level III, retrospective observational study.

Surgical hip dislocation with relative femoral neck lengthening and retinacular soft-tissue flap for sequela of Legg-Calve-Perthes disease.

OBJECTIVE: Correction of post-LCP (Legg-Calve-Perthes) morphology using surgical hip dislocation with retinacular flap and relative femoral neck lengthening for impingent correction reduces the risk of early arthritis and improves the survival of the native hip joint. INDICATIONS: Typical post-LCP deformity with external and internal hip impingement due to aspherical enlarged femoral head and shortened femoral neck with high riding trochanter major without advanced osteoarthritis (Tönnis classification ≤ 1) in the younger patient (age < 50 years). CONTRAINDICATIONS: Advanced global osteoarthritis (Tönnis classification ≥ 2). SURGICAL TECHNIQUE: By performing surgical hip dislocation, full access to the hip joint is gained which allows intra-articular corrections like cartilage and labral repair. Relative femoral neck lengthening involves osteotomy and distalization of the greater trochanter with reduction of the base of the femoral neck, while maintaining vascular perfusion of the femoral head by creation of a retinacular soft-tissue flap. POSTOPERATIVE MANAGEMENT: Immediate postoperative mobilization on a passive motion device to prevent capsular adhesions. Patients mobilized with partial weight bearing of 15 kg with the use of crutches for at least 8 weeks. RESULTS: In all, 81 hips with symptomatic deformity of the femoral head after healed LCP disease were treated with surgical hip dislocation and offset correction between 1997 and 2020. The mean age at operation was 23 years; mean follow-up was 9 years; 11 hips were converted to total hip arthroplasty and 1 patient died 1 year after the operation. The other 67 hips showed no or minor progression of arthrosis. Complications were 2 subluxations due to instability and 1 pseudarthrosis of the lesser trochanter; no hip developed avascular necrosis.

Femoral osteotomies for the treatment of avascular necrosis of the femoral head.

OBJECTIVE: Unloading of the area of necrosis out of the weight-bearing region by shifting healthy bone in the main weight-bearing area, which may delay the progression of the necrosis and enable healing. INDICATIONS: Circumscribed osteonecrosis of the femoral head without advanced degenerative signs (Tönnis grade ≤ 1) in the relatively young patient (age < 50 years). CONTRAINDICATIONS: Radiographic joint degeneration (> Tönnis grade 1); extensive avascular necrosis (Kerboul angle > 240°); advanced lesions (≥ Association Research Circulation Osseous [ARCO] classification 3b). SURGICAL TECHNIQUE: By performing a surgical hip dislocation, full access to the hip joint is gained. A femoral varus osteotomy is used to turn the necrotic lesion of the femoral head out of the central weight-bearing area and more medially. Osteosynthesis is performed with an angular stable screw or a blade plate. Via a trapdoor procedure, direct debridement and autologous bone grafting from the trochanter major is possible. The cartilage flap is preserved whenever possible or supplanted by an autologous matrix-induced chondrogenesis (AMIC). POSTOPERATIVE MANAGEMENT: A passive motion device is installed during hospital stay beginning immediately after surgery to prevent capsular adhesions. After surgery, patients are mobilized with partial weight-bearing of 15 kg with the use of crutches for at least 8 weeks. Forced abduction and adduction as well as flexion of more than 90° are restricted to protect the trochanteric osteotomy. After radiographic confirmation of healing at the 8­week follow-up, stepwise return to full weight-bearing is allowed and abductor training is initiated. RESULTS: Nine patients (10 hips) with osteonecrosis of the femoral head were treated with surgical hip dislocation and varus osteotomy. Six hips were treated with autologous bone grafting, four hips with antegrade drilling. Chondral lesions were sutured in four cases, whereas two cases needed an AMIC treatment. The mean age at operation was 29 ± 9 years (20-49), and the mean follow-up time for all patients was 3 ± 2 years (1-7). Conversion to a total hip prosthesis was required for one hip with progressing arthrosis. The other nine hips showed no progression of necrosis and an improved clinical outcome. Complications were pseudarthrosis of the femoral osteotomy and pseudarthrosis of the greater trochanter.

[Femoroacetabular Impingement - Current Understanding]. / Femoroazetabuläres Impingement ­ aktuelles Verständnis.

Femoroacetabular impingement (FAI) is a painful and early contact between the proximal femur and the acetabular rim or the pelvis. The pathological bony abutment typically leads to a characteristic pattern of chondrolabral damage and is one of the main reasons for development of early osteoarthritis in the young hip joint. Classically, FAI was described as an intraarticular problem but the extraarticular impingement has recently gained in importance. This article provides an overview of the concept of FAI, the clinical presentation, the radiological assessment including its coxometric parameters and the treatment options currently available.