Intraoperative autotransfusion in hip arthroplasty.

Two groups of patients having primary or revision total hip replacement were studied during a period of 11 months. The first group of 40 consecutive patients consented to have whole blood collected coincident with acute normovolemic hemodilution. An inventory of autologous red blood cells, plasma, and platelets was prepared in the operating room as a preliminary to surgery. Subsequently, the same supplies and equipment were used for autotransfusion intraoperatively. In a case-control study, another 40 patients having total hip replacements were matched for age, gender, and weight. The second group of patients refused hemodilution and received autotransfusion alone. The perioperative transfusion requirements of the two groups were compared. The total blood product donor exposure rate of the first group was 1/4 of the controls (0.6 and 2.4 donor units per patient, respectively). The average length of stay in the hospital after surgery for the first group was shortened significantly (6.2 versus 8.4 days), possibly from less immunogenic insult associated with increased transfusions of autologous blood products. Hemodilution, followed by autotransfusion, was cost effective in primary and revision total hip replacements, autotransfusion alone was cost effective only in revision arthroplasty.

Femoral surface strain in intact composite femurs: a custom computer analysis of the photoelastic coating technique.

Understanding how forces are distributed through the proximal femur has many clinical applications for surgeons, researchers, and prosthetic designers. A new system for two-dimensional analysis of femoral surface strain was developed and applied to intact composite femurs. The photoelastic coating method was used to resolve the surface strain under axial loading, and strain analysis was performed using digital imaging of the strain patterns and original computer programs. The technique provides qualitative and quantitative data that describes overall femoral surface strains more completely than previous point analysis and strain gauge techniques. Results from repeated testing found the photoelastic process, computer imaging and computer analysis of strain areas to be statistically repeatable.

The efficacy of prophylaxis with low-dose warfarin for prevention of pulmonary embolism following total hip arthroplasty.

The selection of a prophylaxis regimen and its implementation have been influenced considerably by the decreased duration of hospital stays and the pressures of cost containment. The purpose of the present study was to determine the rate of symptomatic pulmonary embolism both before and after discharge, the number of days required to achieve an adequate level of anticoagulation, and the complications associated with the use of low-dose warfarin after total hip arthroplasty. Between 1987 and 1993, 1099 primary and revision total hip arthroplasties were performed in 940 patients who received low-dose warfarin for prophylaxis against thromboembolic disease. The average duration of prophylaxis was fifteen days (range, one to twenty-nine days). The target level of anticoagulation (as indicated by a prothrombin time of fourteen to seventeen seconds) was achieved an average of three days (range, one to sixteen days) after the operation. The level of anticoagulation was lower than the target range at the time of discharge after 257 total hip arthroplasties (23.4 per cent), and the target level was never achieved during the period of hospitalization after fifty-four such procedures (4.9 per cent). Twelve total hip arthroplasties were associated with a symptomatic pulmonary embolism; the over-all prevalence of this complication therefore was 1.1 per cent (95 per cent confidence interval, 0.4 to 1.9 per cent). Four pulmonary emboli were diagnosed before discharge and eight, after discharge. A fatal pulmonary embolism occurred after one procedure (0.1 per cent). Patients who had a history of symptomatic venous thromboembolic disease had a significantly increased risk of symptomatic pulmonary embolism after total hip arthroplasty (p = 0.001, Fisher exact test). A major bleeding episode occurred after thirty-two total hip arthroplasties (2.9 per cent). Patients who had a prothrombin time of more than seventeen seconds had a significantly increased risk of hematoma formation (p = 0.003, chi-square analysis). Prophylaxis with low-dose warfarin is safe and effective for the prevention of pulmonary embolism after total hip arthroplasty.

Endoprostheses for osteonecrosis of the femoral head. A comparison of four models in young patients.

Eighty-eight hip arthroplasties were carried out in 75 patients, all aged 50 years or less, with osteonecrosis. All the operations were carried out by one surgeon. Four different methods were used: a standard cemented arthroplasty; a cemented THARIES surface replacement; an uncemented surface replacement; a cemented titanium femoral surface hemiarthroplasty. Comparable clinical improvement occurred in all 4 groups initially. Aseptic loosening, with intersurface degradation and osteolytic lesions, was the most common cause of failure in the 3 types which had a polythene bearing. Polyethylene is the major contributor to bone loss around the endoprosthesis and loosening. Fixation of the surface hemiarthroplasty remained intact in every patient and failure was secondary to wear of the acetabular cartilage. We recommend surface hemiarthroplasty as an interim solution for young patients with stage III or early stage IV osteonecrosis because this procedure conserves bone stock, there is little osteolysis and it can easily be revised.

Dislocation of a total hip arthroplasty caused by iliopsoas tendon displacement.

The iliopsoas tendon was caught behind the prosthetic neck after an early anterior dislocation of a revised total hip arthroplasty. The displaced tendon caused instability with successive dislocations that necessitated open reduction. The diagnosis of iliopsoas tendon interposition should be suspected when an early anterior dislocation of a total hip arthroplasty is followed by a concentric reduction and a dramatic change in stability.

Tripolar hip replacement for recurrent prosthetic dislocation.

An innovative treatment is described for unstable total hip arthroplasty that uses a large inside diameter acetabular cup and a bipolar femoral head sized to approximate the diameter of the normal hip. Eight consecutive patients with recurrent prosthetic dislocations were treated with this tripolar hip. Joint stability was achieved in all patients, who have an average of 4.2-years' followup (range, 2.6-6.3 years).

Precision-fit surface hemiarthroplasty for femoral head osteonecrosis. Long-term results.

Cemented Ti-6Al-4V components were used to resurface ten femoral heads in nine young adult patients with osteonecrosis of the femoral head (average age 32 years; range 20 to 51). There were eight hips at Ficat stage III and two at stage IV. Five hips have maintained satisfactory function for an average period of 11.2 years (10 to 12.2) with no radiographic evidence of component loosening or osteolysis; five have been revised after an average period of 7.8 years (3.3 to 10.3) for pain caused by deterioration of the acetabular cartilage. No component required revision for loosening and the specimens retrieved at revision showed no evidence of osteolysis despite burnishing of the titanium bearing surface and the presence of particulate titanium debris in the tissues.