Biomedical subjects
Publications and source records attributed to A Avai.
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.
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.
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.
We have reviewed the results of 106 intertrochanteric osteotomies performed for osteonecrosis of the femoral head. The average age at operation was 47.5 years. At two years from operation 71% of the hips had a clinically satisfactory result and at final follow-up, an average of 8.2 years after operation, 58% continued to have excellent or good rating. Twenty-four hips had needed total replacement or arthrodesis because of pain. Patients aged less than 55 did better than those operated on after that age, and hips with an idiopathic or post-traumatic aetiology did considerably better than alcohol-induced or steroid-induced cases. In view of these findings we believe that in the younger adult, in the absence of metabolic bone disease or advanced joint destruction, intertrochanteric osteotomy should be considered for the treatment of osteonecrosis.
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 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.
A total of 41 patients affected with recurrent subluxations or dislocations of the patella treated with different surgical methods between 1972 and 1981 were examined. Radiographic and clinical monitoring according to Crosby-Insall in 35 patients ranges from 10 to 20 years, with the following results: excellent: 17%; good: 69%; fair: 14%; poor: 0; recurrent dislocations or subluxations: 0.