Ischemic necrosis of the femoral head occurring after the treatment of congenital dysplasia of the hip can negatively affect the long-term prognosis of the involved hip. The purpose of the study was to evaluate a number of clinical and radiological risk factors for AVN after non-operative treatment of DDH. Clinical data and radiographs of 77 patients with103 abnormal hips treated because of developmental dysplasia of the hip by closed reduction followed by cast immobilization were reviewed retrospectively. The average age of patients at the time of reduction was 16 months (ranged, 4 to 28) and the average final follow up was 22,4 years (ranged from 13 to 47 years). Kalamchi and MacEwen classification system was used for evaluation of the AVN. Avascular necrosis was found in 35,9% of the treated hips. We established the influence of several radiological and clinical data on the incidence and severity of AVN. Conclusion: In our analysis the degree of initial dislocation according to Tönnis classification is an important risk factor for AVN. Age at the onset of treatment, presence and size of ossific nucleus, the use and period of preliminary traction, previous treatment with Frejka pillow or Pavlik splint, sex and side were not associated with the incidence and severity of ischemic necrosis. The results have been analysed statistically.
The purpose of this study is to determine how the lateral shape of the acetabulum changes during Perthes disease and if there is any correlation between the lateral acetabulum shape and final result and type of treatment. The study population consisted of 243 patients with unilateral involvement who had reached skeletal maturity at last follow up. There were 35 (14.4%) female and 208 (85.6%) male patients. The mean age at the onset of symptoms was 7 years and 1 month. AP X-ray films were estimated during fragmentation, reossification and last follow up. Group A consisted of 56 hips, 126 hips were classified as group B and 61 hips as group C according to the Herring classification. For the lateral acetabular shape we proposed a classification: group A – a normal concave acetabular roof, group B – a horizontal flat roof and group C – a roof convexly rounded and up going. All hips were treated by containment methods (bed rest and traction in abduction-78 hips, Petri cast-31 hips, brace-94 hips, varus osteotomy-20 hips, Salter oste-otomy-12 hips and shelf arthroplasty-8 hips). The outcomes of treatment were evaluated according to the Stulberg classification. During fragmentation stage we found 78 (32.1%) hips with normal lateral acetabular shape-type A. Horizontal roof-type B was noted in 136 (56%) hips and in 29 (11.9%) type C was observed. We observed improvement in the shape of lateral acetabulum after treatment. At the last follow up there were 124 (51%) hips with type A, 81 (33.3%) with type B and 38 (15.7%) with type C. Statistical analysis revealed significant correlation between lateral acetabular shape and Stulberg classification. A normal concave acetabular roof at the fragmentation stage leaded mainly to Stulberg group 1and 2 whereas a roof convexly rounded and up going leaded to Stulberg group 3, 4 or 5 (p<
0.0001). Analysis showed no statistical significant correlation between treatment by using bed rest and traction in abduction, Petri cast, braces and development the lateral acetab-ular shape (p=0.09). Only treatment by using surgical methods improved the lateral acetabular shape at the last follow up (p=0.0015). The acetabulum is a mould for remodeling of the deformed femoral head in Perthes disease and the lateral acetabulum plays the most important role. We can expect that normal shape of the acetabulum gives good result at final follow up whereas a roof convexly rounded usually follows to Stulberg group 3, 4 or 5. Only surgical treatment improves the shape of the acetabulum.