The objective of this study is to determine an optimal antibiotic-loaded
bone cement (ALBC) for infection prophylaxis in total joint arthroplasty
(TJA). We evaluated the antibacterial effects of polymethylmethacrylate
(PMMA) bone cements loaded with vancomycin, teicoplanin, ceftazidime,
imipenem, piperacillin, gentamicin, and tobramycin against methicillin-sensitive Objectives
Methods
We studied the use of autologous pre-donated blood transfusion in surgery for scoliosis in 45 patients who were divided into two groups; 27 who pre-donated autologous blood (group 1) and 18 who were planned recipients of allogenic blood (group 2). Normovolaemic haemodilution and intra-operative blood salvage was used in six patients in group 1 and three patients in group 2. The two groups did not differ significantly with respect to age, American Society of Anaesthesiologists score, mean operative time, number of vertebral segments fused, total blood loss, length of stay in intensive care and length of stay in hospital. The risk of requiring allogenic blood transfusion was found to be significantly less in group 1 (7.4% ν 88.9%, p <
0.001). Only 5.21% of autologous units were wasted. Although intra-operative blood salvage reduced the total blood loss in both groups, it did not affect the need for subsequent allogenic transfusion or reduce the number of pre-donated autologous units which were given (p <
0.67). Autologous blood transfusion required extra time, personnel, resources and cost £28.88 per patient more than allogenic transfusion, however, the projected costs at May 2002 make this programme cost-effective by £51.54 per patient. Pre-donated autologous blood transfusion is acceptable and safe in scoliosis surgery. It significantly reduces the subsequent requirement of allogenic transfusion. Although the cost is currently more than allogenic transfusion, with the increase in the costs of the latter and the decrease in potential donors which is anticipated, pre-donation of autologous blood will become comparatively cost-effective.
Antibiotics are frequently administered prophylactically in spinal procedures to reduce the risk of disc space infection. There is still controversy, however, over which antibiotics are able to penetrate the intervertebral disc effectively and whether the charges on the antibiotics are important in determining their ability to diffuse into the negatively charged intervertebral disc. In a prospective randomised double blind clinical study, we examined the penetration of two commonly used antibiotics, cefuroxime (negatively charged) and gentamicin (positively charged), into the intervertebral discs. Twenty patients, randomised into two separate groups, received either 1.5g cefuroxime or 5 mg/kg gentamicin prophylactically two hours before their intervertebral discs removed. A blood specimen, from which serum antibiotic levels were determined, was obtained simultaneously with each discectomy. Clinical therapeutic levels of antibiotic were detectable in the intervertebral discs of all the ten patients who received gentamicin. Only two of the ten patients (20%) who received cefuroxime had quantifiable level of antibiotic in their discs even though serum levels of cefuroxime were at therapeutic levels in all ten patients. Our results showed that cefuroxime does not diffuse into human intervertebral discs as readily as gentamicin and suggest that the charge due to ionisable groups on the antibiotics is important in determining the penetration of antibiotics. We therefore recommend the use of gentamicin in a single prophylactic dose for all spinal procedures to reduce the incidence of post-operative discitis.
We made a clinical study of polyethylene wear in 240 hips of 187 patients having primary total hip arthroplasties from 1989 to 1990, using uncemented Osteonics components, with a head size of 26 mm. We excluded cups with anteversion of over 20° and measured linear wear by a new method using a digitiser and special software of our design. Follow-up was from two to five years (mean 4.3). The mean age at operation was 50.3 years, with more men than women (1.4:1). The mean linear wear per year was 0.15 mm; this did not increase with the longevity of the prosthesis (p = 0.54). In 59 hips showing evidence of osteolysis, the mean linear wear rate was significantly higher at 0.23 mm/year (p <
0.001). The mean linear wear rate also correlated significantly with age at the time of operation (p = 0.008), but we found no significant correlations with body-weight, gender, aetiology of the disease, thickness of polyethylene, or cup position. Our new method of measurement is time-saving and reproducible. The results confirm the greater rate of linear wear of polyethylene in patients showing osteolysis and in those who are younger.