{'fraction_non_alphanumeric': 0.027900146842878122, 'fraction_numerical': 0.032305433186490456, 'mean_word_length': 4.518218623481781, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Radiological outcome analysis of transtrochanteric curved varus osteotomy for osteonecrosis of the femoral head at a mean follow-up of 12.4 years.

We investigated the factors related to the radiological outcome of a transtrochanteric curved varus osteotomy in patients with osteonecrosis of the hip. We reviewed 73 hips in 62 patients with a mean follow-up of 12.4 years (5 to 31.1). There were 28 men and 34 women, with a mean age of 33.3 years (15 to 68) at the time of surgery. The 73 hips were divided into two groups according to their radiological findings: group 1 showed progression of collapse and/or joint-space narrowing; group 2 had neither progressive collapse nor joint-space narrowing. Both of these factors and the radiological outcomes were analysed by a stepwise discriminant analysis. A total of 12 hips were categorised as group 1 and 61 as group 2. Both the post-operative intact ratio and the localisation of the necrotic lesion correlated with the radiological outcome. The cut-off point of the postoperative intact ratio to prevent the progression of collapse was 33.6%, and the cut-off point to prevent both the progression of collapse and joint-space narrowing was 41.9%. The results of this study indicate that a post-operative intact ratio of 33.0% is necessary if a satisfactory outcome is to be achieved after this varus osteotomy.