We suggest that in Perthes' disease the blood supply of the LEAs is impaired at their origin and that revascularisation occurs from this site by ingrowth of small vessels into the femoral epiphysis. This process may be the result of recurrent ischaemic episodes.

We performed superselective angiography in 28 hips in 25 patients with Perthes' disease in order to study the blood supply of the lateral epiphyseal arteries (LEAs). Interruption of the LEAs at their origin was observed in 19 hips (68%). Revascularisation in the form of numerous small arteries was seen in ten out of 11 hips in the initial stage of Perthes' disease, in seven of eight in the fragmentation stage and in five of nine in the healing stage. Penetration of mature arteries into the depths of the epiphysis was seen in four of nine hips in the healing stage. Vascular penetration was absent in the weight-bearing portion of the femoral head below the acetabular roof. Interruption of the posterior column artery was seen where it passed through the capsule in seven hips when they lay either in internal rotation or in abduction with internal rotation. We suggest that in Perthes' disease the blood supply of the LEAs is impaired at their origin and that revascularisation occurs from this site by ingrowth of small vessels into the femoral epiphysis. This process may be the result of recurrent ischaemic episodes.

Posterior rotational osteotomy in 46 hips of 39 patients with femoral head osteonecrosis was reviewed radiographically and clinically after 2-12 years of follow-up (mean 5 years). The age of the patients at the time of surgery ranged from 18 to 60 years, with a mean of 35 years. There were 18 women and 21 men. The cause of the osteonecrosis was steroid administration in 14, alcohol abuse in 5, trauma in 16, and no apparent risk factor in 4. According to the Ficat staging system, 2 hips were stage II, 30 hips III, and 14 hips stage IV. All hips had an extensive lesion. Forty-one hips showed less than 1/3 noncollapsed posterior living area, which was a contraindication for traditional anterior rotational osteotomy. The posterior rotational angle was 60-180 deg with an mean of 127 deg. Recollapse of the final follow-up anteroposterior radiograph was prevented in 36 hips (78%). Progressive joint space narrowing was found in 12 hips (26%). Of these hips, 9 suffered recollapse, while the remaining 3 hips did not. Clinically, 32 hips (70%) showed excellent or good results (both hips in stage II, 23 of 30 hips in stage III, 7 of 14 hips in stage IV. A fair or poor result was seen in 14 hips (30%)). These results suggest that posterior rotational osteotomy is effective in delaying the progression of degeneration for large necrotic lesions, especially in young patients. Extent of rotation is limited to 150 deg because of limitations of bone quality. The indications should be refined further, and longer term follow-up is necessary.

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