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Biomedical subjects

G Belhobek

Publications and source records attributed to G Belhobek.

6 recordsLinked to original sources

Total knee replacement: radiologic findings in failure of porous-coated metal-backed patellar component.

One technique for replacing the articular surface of the patella in total knee replacement is the use of a cementless porous-coated metal-backed polyethylene component. Anteroposterior, lateral, and Merchant or skyline radiographs in 10 cases of porous-coated metal-backed components that failed were evaluated for component alignment, component displacement, radiolucencies, loose beads, and integrity of the patellar component. Component failure was documented by surgery in all 10 cases. Seven cases of failure involved the patellar pegs or junction of the pegs with the metal backing and three cases involved the polyethylene portion. In the seven cases of peg-metal backing failure, three cases showed loose beads before failure and seven cases showed displacement of the metal backing at time of failure. All three cases of polyethylene failure showed narrowing or displacement of the polyethylene portion. Our experience shows that displacement of the metal backing, displacement of the polyethylene, and disruption of patellar pegs are seen in failed porous-coated metal-backed patellar components. Loose beads may be seen before peg-metal backing failure.

Humans

Problems in applying expert system technology to radiographic image interpretation.

A prototype expert system was developed to study the problems applying expert system technology to radiographic image interpretation. The Radiographic Image Interpretation System (RIIS) was developed on a microcomputer using Turbo Prolog, a low cost implementation of the prolog programming language. The present implementation of RIIS was developed to highlight potential problems in applying expert system technology in the evaluation of radiographic images. It was believed that the evaluation of this prototype expert system should include a large number of users unfamiliar with the program's use as this would probably be the case in clinical use of an image interpretation expert system. At present, the expert system deals with a limited domain of focal bony lesions. Twenty cases of pathologically proven bony lesions of varying difficulty were used to evaluate potential problems in the use of this expert system technology. RIIS, with the 20 sample cases, was presented as an exhibit at the 1987 Radiological Society of North America (RSNA) meeting to evaluate the potential problems with inexperienced users. These results were compared with those of experienced users. When a musculoskeletal radiologist, familiar with the programs use, provided the "proper description," the program averaged the correct diagnosis in the top five 80% of the time. During the program's use at the RSNA meeting, the program selected the correct diagnosis in the top five 22% of the time.

Bone Neoplasms

Magnetic resonance imaging of musculoskeletal infections.

In summary, MRI has a high sensitivity for the detection of inflammatory disease involving the musculoskeletal system. Because of the usual anatomic pattern of involvement in the vertebral column, there is also a high specificity. In the appendicular skeleton and pelvis, it is unclear whether MRI can add to the sensitivity and specificity of radionuclide studies in uncomplicated cases of acute infection. However, it can be performed more rapidly and provides greater anatomic detail and delineation of the extent of marrow involvement than radionuclide studies. MRI can be used in both acute and chronic osteomyelitis to guide a diagnostic interventional test to the appropriate site. It is capable of excluding involvement of the medullary canal, and it is better than radionuclide studies for differentiating soft tissue infection with periostitis from osteomyelitis. It has only a limited role in the immediate postoperative period, and in the presence of metallic implants, an indium-labeled leukocyte scan may be more appropriate. Finally, it must be remembered that the current data base of MRI is small and that further refinement of its role in the evaluation of inflammatory processes will be forthcoming.

Adult

Stress fractures of the tarsal navicular. A case report.

In summary, the diagnosis of a tarsal navicular stress fracture should be entertained in the athlete with ill-defined midfoot pain. Technetium bone scans will often point the clinician in the right direction; biplanar CT scans will pin-point the diagnosis and can be invaluable in perioperative planning. Subsequent treatment, however, must be determined on a clinical rather than a radiographic basis.

Adolescent