Radiographic assessment of distal femur cemented stems in tumor endoprostheses.

BACKGROUND: Distal femoral endoprosthesis (DFE) has become the optimal method of reconstruction in the skeletally mature patients treated for malignant bone tumor. Albeit literature has reported wide range of aseptic loosening in cemented components (6-32%), few authors showed that cement was not detrimental to long-term success of primary distal femoral implants possibly relating to cementing technique. METHODS: A series of consecutive of DFE (MRS and GMRS, Styker Orthopaedics, Mahwah, NJ) was retrospectively reviewed for evidence of loosening on plain radiographs. All prostheses had the standard straight 127-mm stem and a cemented polyethylene tibial component. Cementing technique involved reaming line to line to the selected stem size and cementing without pressurization. Radiographs were assessed by two independent blinded reviewers and scored for radiolucent zones (>1 mm) and graded as not loose, possibly, probable and definite loose. Furthermore, the final reamer/stem diameters, length of resection, tumor type, adjuvant treatment modalities, bushing exchange/revision surgery and infection rate were recorded. RESULTS: There were 70 patients and none were lost to follow-up. The average radiographic follow-up was 7.2 years (58% had f/u >5 years). Examiner A found 89% of femoral components to be "Not Loose" and 11% (n = 6) "Possibly Loose". Examiner B found 96% of femoral components to be "Not Loose" and 4% (n = 2) to be "Possibly Loose". No components scored as probably or definitely loose. Two DFE stems were reported as "Possibly Loose" by both reviewers. No femoral stem required revisions for either loosening, femur fracture or metal failure. Although infection was frequent, there was no septic loosening. CONCLUSION: Despite our study limitations, no radiographic evidence of loosening was found. Cementing distal femur prosthesis with a tight canal fit and with a thin and inconsistent cement mantle appears to be a viable option at short and medium term.

Anatomic study of infrapopliteal vessels.

The purpose of this project is to study and analyse the anatomical variations of the infrapopliteal vessels concerning their branching pattern. A reliable sample of one hundred formalin-fixed adult cadavers was dissected by the Anatomical Laboratory of Athens University. The variations can be classified in the following way: the normal branching of the popliteal artery was present in 90%. The remainder revealed variant branching patterns: hypoplastic or aplastic posterior tibial artery and the pedis arteries arising from the peroneal (3%); hypoplastic or aplastic anterior tibial artery (1.5%); and the dorsalis pedis formed by two equal branches, arising from the peroneal and the anterior tibial artery (2%). The variations were more frequent in females and in short-height individuals. Knowledge of these variations is rather important for any invasive technic concerning lower extremities.

Gene-representing cDNA clusters defined by hybridization of 57,419 clones from infant brain libraries with short oligonucleotide probes.

Diverse biochemical and computational procedures and facilities have been developed to hybridize thousands of DNA clones with short oligonucleotide probes and subsequently to extract valuable genetic information. This technology has been applied to 73,536 cDNA clones from infant brain libraries. By a mutual comparison of 57,419 samples that were successfully scored by 200-320 probes, 19,726 genes have been identified and sorted by their expression levels. The data indicate that an additional 20,000 or more genes may be expressed in the infant brain. Representative clones of the found genes create a valuable resource for complete sequencing and functional studies of many novel genes. These results demonstrate the unique capacity of hybridization technology to identify weakly transcribed genes and to study gene networks involved in organismal development, aging, or tumorigenesis by monitoring the expression of every gene in related tissues, whether known or still undiscovered.