An assessment of the genotoxic effects of landfill leachates using bacterial and plant tests.

Two bacterial tests (the Ames test and the umu-test) and the Allium test were used to assess the genotoxicity of aqueous leachates from municipal solid waste landfill sites in Southern Poland. A comparison of the sensitivity of the applied tests was performed. None of the tested samples revealed genotoxic activity in the umu-test and thus did not appear to be sensitive enough for evaluations of leachates. Two out of 22 leachates were described as genotoxic in the Ames test and 3 out of 6 leachates in the Allium test. All of the analyzed leachates samples affected cell divisions. Two of the tests applied, the Allium and Ames test, revealed the high genotoxicity of leachate 4. Among the bioassays used in these studies, the Allium test proved to be more sensitive than bacterial tests for the investigation of leachate toxicity. The results suggest that the Allium cytogenetic bioassay is efficient and simple for genotoxicity studies of leachates. The potential correlations between the chemical characteristics and genotoxic effects is discussed. The biological effects of selected appeared to be related to chemical parameters. Leachates have a genotoxic potential and pose a risk to human health and the environment. A combination of biotests and chemical analyses is the best approach for the assessment of the risk or impact of leachates.

Radiation prophylaxis for heterotopic ossification of the knee.

Heterotopic ossification (HO) occurs in 42% of patients who have undergone total knee arthroplasty. Bone formation usually is found in the quadriceps expansion and causes minimal to no symptoms. Specific therapy usually is unnecessary, but cases have been reported in which manipulation under anesthesia or revision arthroplasty has been required. We report a small series of 5 patients (6 knees) who have undergone surgical intervention for HO of the knee with radiotherapy given postoperatively for prophylaxis against future HO. Although this series is small, it appears that the use of prophylactic radiation may reduce recurrence after resection of symptomatic HO after total knee arthroplasty. Further investigation is required to confirm these preliminary findings.

Multidirectional deformation in fully congruent acetabular components.

Most clinical studies have used femoral head migration as an index of acetabular wear, but a previous study showed multiple wear vectors in 30% of retrieved acetabular components with noncongruent liners. The origin of multiple wear vectors is unclear, and it has been suggested that polyethylene creep in a noncongruent shell might influence deformation on the articular surface. We used shadowgraph and volumetric methods to evaluate the extent and direction of surface deformation of 37 retrieved polyethylene liners that were fully congruent to a single design of metal backing. The results show that multiple deformation vectors are relatively common in retrieved acetabular cups (27% in this study) and are independent of congruency between liner and metal backing, rim impingement, and backside creep. Polyethylene liners with multiple wear vectors were significantly thinner than those of cups with a single vector. The origin of multiple vectors is still unclear, but clinical and laboratory studies measuring linear wear alone without recognizing multiple vectors underestimate total in vivo volumetric wear.

The infected prosthetic total temporomandibular joint replacement: report of two cases.

Two cases of infected total temporomandibular joint replacements are reported. The WBC count, erythrocyte sedimentation rate, and temperature were within normal limits, but erythema, edema, and pain provided the initial clue to the infection. Ultrasonography ultimately revealed a fluid collection and allowed aspiration of the fluid-filled cavity, providing a diagnosis and directing antibiotic therapy.

Reversible cartilage staining technique for defining articular weight-bearing surfaces.

A reversible cartilage staining technique, applicable to anatomical specimens, has been developed to define the weight-bearing patterns of the ankle joint. The method represents a rapid and accurate procedure for the determination of cartilage contact patterns in multiple positions of function. This technique should prove a useful tool in the detection of weight-bearing areas of other synovial joints.

Effect of gentamicin on shear and interface strengths of bone cement.

Antibiotic impregnated cement offers a potential method for salvage of infected total joint replacements. The addition of gentamicin in concentrations of .5, 1.0, and 2.0 per 40 significantly affects the shear strength of Palacos acrylic bone cement. The clinical significance of this strnegth drop is not clear. Large grained antibiotic additives have deleterious effect on shear strength. Measurements were made to determine the effect of gentamicin concentration on the bone-cement interface strength but no trend could be determined. The interface strength was much less than the strength of Palacos alone and suggested that bone strength is the limiting factor.