Aims: The purpose of this retrospective study was to report on the minimum 10-year follow-up results of a consecutive series of cemented low friction total hip arthroplasties performed for avascular necrosis of the femoral head. Methods: One hundred and twenty-two THAs in 96 patients were performed between January 1980 and December 1990. All prostheses were of Charnley- Kerboull design, combining a 22.2-mm femoral head and an all-polyethylene socket. Both components were cemented. The mean age of the series was 50.8 ± 13.3 years (21–85 years). Eighty hips were graded Ficat III and 42 hips were graded Ficat IV. Results: At the minimum 10-year follow-up evaluation, 59 patients (75 hips) were still alive and had not been revised at a mean of 13.9 years (10–21 years), 7 patients (7 hips) had been revised, 20 patients (24 hips) had died from unrelated causes, and 10 patients (16 hips) were lost to follow-up. The mean dñAubignŽ hip score was 17 ± 1 at the latest follow-up. The mean wear rate for unrevised hips was 0.07± 0.06 mm per year. Revision was performed for polyethylene wear associated with periprosthetic osteolysis in 6 hips and for deep sepsis in one. Three hips had recurrent dislocations. The survival rate at 15 years, using revision for any reason as the end-point, was 88.5% (95% conþdence interval, 80.2 to 96.9%). Conclusions: This series indicated that Charnley Kerboull low friction total hip arthroplasty for avascular necrosis could provide satisfactory long-term clinical and radiologic results.

Purpose: The purpose of this retrospective study was to assess clinical and radiological outcome at ten years follow-up at least in a continuous series of total hip arthroplasties performed in patients with aseptic necrosis of the femoral head.

Material and methods: The series included 122 arthroplasties performed between January 1980 and December 1996 in 96 patients (26 women and 70 men), aged 50.8±13.3 years (range 21–85 years). The underlying cause was essential necrosis in 40.6%, cortocosteroid threapy in 19.8%, chronic alcoholism for 17%, trauma for 12%, and another medical cause for 10%. The Ficat and Arlet classification was grade IV 80 hips, grade III 42 hips. All arthroplasties were performed via the transtrochanteric approach. Cemented Charnley-Kerboull implants were used with a metal-polyethylene couple in all cases. The Merle d’Aubigné score was used to assess functional outcome. Cup wear was measured according to Livermore. Actuarial survival curves were calculated.

Results: Follow-up was greater than ten years for all patients (mean 13±2.6 years, range 10–21 years). At last follow-up 59 patients (75 hips) were living and had not undergone revision and seven patients (seven hips) had undergone revision of the acetabular and/or femoral component. Twenty patients (24 hips) had died and ten patients (16 hips) were lost to follow-up. Revision procedures were performed for periacetabular osteolysis in one hip, infection in one hip, and acetabular loosening in five hips. Three patients experienced luxation or subluxation. The mean preoperative function score was 11 (range 5 – 16) compared with 17 (14–18) at last follow-up (p < 0.05). Clinical outcome was good or excellent in 95% of the patients and fair or poor in 5%. Mean overall cup wear was 0.965 mm (0–5) for non revised hips. Lucent lines were found around eleven acetabular implants and six femoral implants. Cumulative survival, considering revision as failure, was 88.5% at 15 years (95% confidence interval 80.2 – 96.9%).

Discussion and conclusion: The results of this series lead to the conclusion that low-friction total hip arthroplasty is the treatment of choice for advanced stage femoral head necrosis.

1. The surgical treatment of idiopathic aseptic necrosis of the femoral head has been reviewed in the light of experience gained from 240 hips operated upon.

2. When pain is not severe and the necrosis of bone as seen in serial radiographs is not rapidly progressive, simple observation and palliative medical treatment are indicated.

3. When pain disables the patient and collapse of the head is progressive, operation is indicated. If radiographs show necrosis limited to the anterior part of the head and sparing an arc of at least 20 degrees of the lateral part, either an osteotomy bringing the shaft into adduction and flexion or an "adjusted cup" arthroplasty is indicated, with a preference for the latter because it gives better results in a shorter time.

4. If at arthrotomy the necrosis appears to involve the posterior slope of the head, prosthetic replacement, preferably total, should be undertaken.

1. Idiopathic necrosis of the femoral head is generally considered to be a rare disease but it appears to be rather frequent in France in view of the fact that 139 cases were recorded in the orthopaedic clinic of Hôpital Cochin between 1959 and 1963. Ninety cases treated by operation have been analysed in this paper. Men are nearly exclusively affected between the ages of eighteen and seventy, with the highest incidence between thirty and fifty years of age. Both hips are affected in 52 per cent of cases.

2. The etiology is unknown, but steroid therapy was noted in 36 per cent of the cases and some history of slight injury in 30 per cent. The sudden onset of pain in half the cases suggests the obliteration of one of the blood vessels supplying the femoral head.

3. Radiographs are often normal at the time of onset of the symptoms but later they show increased density of the head localised to the antero-superior aspect, and later still collapse of this weight-bearing region. The extent of the lesion appears to be determined from the very beginning rather than to be progressive. The superior joint space is never reduced and may in fact be widened.

4. Pathological examination of the head and neck confirms necrosis of the cancellous bone and the integrity of the overlying cartilage, but shows deep to the necrotic region a highly reactive zone characterised by hypervascularity and raised metabolism. These features have been demonstrated by injection of the blood vessels and also by the uptake of phosphorus 32 and by the succino-deshydrogenase test.

5. In six cases microscopic vascular lesions were found in the antero-lateral pedicle of the femoral head.

6. The high degree of activity of the tissue deep to the necrotic zone gives some hope for revascularisation of the necrotic segment. For this reason protection from pressure may be the way to prevent dramatic collapse of the head. Rest, medical treatment and freedom from weight bearing, however, do not achieve adequate protection. Varus or rotation osteotomy of the femoral neck not only gives relief from pain but appears to prevent collapse of the femoral head.

7. When destruction of the head has already taken place good results may be expected from the insertion of a metallic prosthesis, provided the acetabulum is sound. The results are less favourable when the acetabulum has been altered by secondary arthritic change, and arthrodesis may have to be considered if the disease is unilateral or when a prosthesis has been successfully inserted on the other side.