Total hip replacement after intertrochanteric osteotomy

From 1980 to 1993 we inserted 216 total prostheses into hips which had been treated by varus and valgus-extension intertrochanteric osteotomy. The technique of the operation was more difficult than in hips operated on for the first time because of anatomical changes produced by the osteotomy in the surrounding structures. We have had complications which taught us how to prevent and deal with these problems.

Teicoplanin versus cefamandole in the prevention of infection in total hip replacement

In a prospective, controlled, single-blind study the efficacy of teicoplanin versus cefamandole in preventing infections in total hip replacement was investigated in 496 consecutive patients. A single intravenous dose of teicoplanin (400 mg) was as effective as two intravenous doses of cefamandole (2 g before and 1 g after surgery). No major complications were observed in either group. Infective wound complications were observed only in the cefamandole group. These infections, although not dangerous for the patients, required supplementary antibiotic treatment in all cases. Teicoplanin is a reasonable choice as a prophylactic agent in orthopaedic surgery when a high risk of infection due to staphylococci is present.

[Loosening of total hip prosthesis]

The problem of total hip prosthesis is an immediate and long-term stability. An insufficient bone anchorage of the prosthesis produces a tissue reaction around the implant that causes a loosening. The hight incidence of loosening of cemented total prosthesis has spurred the research into uncemented implants. The experience at the Busto Arsizio Hip Center (Director Prof. R. Bombelli) with more than 2,800 R.M. uncemented isoelastic total hip prostheses was favorable and the study with the cooperation of Pathology Department (Director Prof. P. Lampertico) of the 82 loosening hips has shown: 1) the importance of the elasticity for a stress transmission to the surrounding bone; 2) the pursuit of the most suitable stem calibre and length; 3) the necessity of a stable primary mechanical fixation, waiting for a biological reaction.

Valgus-extension osteotomy for osteoarthritis of the hip. Indications and long-term results

We reviewed the results of 277 intertrochanteric valgus-extension osteotomies performed between 1973 and 1975 for primary or secondary osteoarthritis. The average age of the patients was 51 years and follow-up varied from 11 to 15 years. At the latest evaluation 67% of the hips were good or excellent on the Merle D'Aubigné scale. Better results were obtained in patients under 40 years of age with unilateral involvement and a mechanical (secondary) aetiology. An elliptical femoral head, minimal subluxation and an adequate pre-operative range of motion were also favourable. There was radiographic evidence of regression of the arthritic changes in 39% of the hips at final review. Valgus-extension osteotomy is effective for secondary osteoarthritis of the hip in selected younger patients, but not for those with primary hip disease or a poor range of movement.

Cementless R.M. isoelastic total hip prosthesis in revision surgery for loose prostheses

Forty-three patients with aseptic mobilization of hip prostheses were submitted to revision surgery using cementless R.M. isoelastic total hip prostheses. The femoral component was substituted in all cases, the acetabular component in 37. Autoplastic bone grafts were required in 27 cases to replace severe bone defects in the acetabulum or femoral diaphysis. All the patients were followed up for an average of 46 months (range 36 to 59 months). The results were good in 38 cases, evaluated both on the Harris scale (average 87 points) and the Charnley method (5.4 points for pain, 5.0 for walking, and 5.2 for movement). There were 2 cases of ankylosis, one case of infection, one paralysis of the peroneal nerve and one proximal migration of the acetabular component. Therefore we believe that the use of cement is contraindicated in revision surgery of the hip, particularly in the presence of severe osteolysis and in younger patients. The isoelastic stem encourages bone reconstruction and cortical thickening in the femoral diaphysis. When there is bone deficiency the cementless acetabulum must always be associated with autoplastic bone grafting.

The isoelastic, noncemented total hip arthroplasty. Preliminary experience with 400 cases

The first 400 patients having cementless isoelastic total hip arthroplasties with a polyacetyl femoral component stem were assessed by independent observers with a minimum review time of two years. Six percent of the patients had died at the time of review; these were mainly elderly patients with subcapital fractures. Ninety-seven percent of the surviving patients appeared for a complete clinical and radiological review. Ninety-two percent of these patients considered that they had a good result following surgery. Six patients (1.6%) developed infection, and three patients (0.8%) required revision procedures, two for femoral loosening and one for recurrent dislocation. Two (0.5%) acetabular components were loose, one of which was associated with infection. In the initial part of the series with narrow-diameter, second-generation femoral components, some had subsided and tilted into varus, but with improved instrumentation and availability of wider diameter femoral components, this problem has been overcome. In order to obtain a more secure mechanical fixation of the femoral component in the medullary canal and to increase implant-bone interface, the third-generation femoral components were used in the latter 48 cases of the series, and clinical and radiological results were excellent with corresponding reduction in the recommended period of gait support. No component had broken. Femoral fractures incurred during surgery by dislocation or impaction had all healed with routine management. These early results are encouraging, but the effectiveness of this prosthesis must be determined by longer follow-up data.

The inclination of the weight bearing surface in the hip joint. The clinical significance of abnormal force

The mechanical basis responsible for the development of secondary osteoarthritis in adults and slipped capital femoral epiphysis in adolescents is discussed, with the role of the oblique weight-bearing surface in generating abnormal shearing forces in these two conditions emphasized. The same biomechanical principles have been found to apply to the acetabular component in total hip implants. A vertical cup position will lead to abnormal stress concentration in the outer edge of the bone implant interface with an increase in shearing forces. The form of the subchondral bone sclerosis on the radiograph has been studied and found to correlate well with the distribution of stresses in the bone implant interface.