RESUMEN
Clinical, radiographic, and scintigraphic results of 33 consecutive unicompartmental knee arthroplasties were reviewed after a mean follow-up period of 68 months (range, 24 to 112 months). Clinical grades employing criteria established by the Hospital for Special Surgery showed 74% good to excellent and 11% fair to poor results. Four knees (15%) required revision to a total knee arthroplasty after an average postoperative interval of 7.4 years. Within the subset of surviving medial compartment arthroplasties (23 knees), superior clinical results were associated with a central or slightly medialized mechanical axis (p < 0.05). Periprosthetic radiolucency showed no correlation with clinical scores or failures resulting in revision surgery. There was no radiographic evidence of progressive arthrosis within the unreplaced compartments. Comparative analysis of preoperative and annual postoperative technetium bone scans showed no temporally related changes indicative of impending prosthetic failure or disease progression within the unoperated compartments. The surgically treated compartments maintained uniformly intense femorotibial activity, whereas the unoperated compartments, including the patellofemoral joint, remained scintigraphically quiescent. Disease progression in unreplaced compartments is unusual after contemporary unicompartmental knee arthroplasty. Most failures and poor results arise from mechanical inadequacies amendable to surgical technique and/or future design considerations.
Asunto(s)
Articulación de la Rodilla/diagnóstico por imagen , Prótesis de la Rodilla , Anciano , Artroplastia/métodos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Radiografía , Cintigrafía , TecnecioRESUMEN
An ultrafast, cine-CT scanner was used to demonstrate the differential mobility of the lateral and medial femoral condyles on their respective tibial plateaus in cadaver knees and to show the kinematic type of motion of the knee joint. Current imaging techniques cannot accomplish this because they do not perform combined quantitative, tomographic, and dynamic studies. Accordingly, this preliminary report presents the data from cine-CT scans of 12 normal intact adult cadaver knees. Scans were obtained at the rate of 14 or 17 per second at 50 or 100 ms exposures through midsagittal planes of the medial and lateral condyles and intercondylar notch. The cine-CT scans were displayed on a CRT and analyzed as closed-loop movies and as isolated images. Each cadaver femoral condyle demonstrated a different combined rolling and gliding motion. Preliminary results on the cadaver knee suggest the lateral femoral condyle moved 2.3 times further on the tibial plateau than its medial counterpart. The percentage of rolling for the lateral condyle was 43%-49%; the percentage of gliding was 51%-57%, with a ratio of rolling to gliding of 1:1.2. The percentage of rolling for the medial condyle was 16%-26%; the percentage of gliding 74%-84% with a ratio of rolling to gliding of 1:3.8. The femoral condyles, tibia, and cruciate ligaments acted as a crossed four-bar linkage in concordance with kinematic theory. The applicability of the cadaver knee results to patient dynamics and diagnosis cannot be determined from this study and awaits further investigations on the in vivo knee. However, ultrafast cine-CT demonstrated the complex knee motion in the cadaver knee joint.
Asunto(s)
Cinerradiografía/instrumentación , Articulación de la Rodilla/diagnóstico por imagen , Movimiento , Tomografía Computarizada por Rayos X/instrumentación , Adulto , Fenómenos Biomecánicos , Humanos , Articulación de la Rodilla/fisiología , Persona de Mediana EdadRESUMEN
A prospective study was performed with 97 patients who had undergone total hip replacement surgery and who were not experiencing pain or other symptoms or problems. The study was intended to determine the normal postoperative appearance of radionuclide scans of the hip following administration of technetium-99m methylene diphosphonate. Five areas of the prostheses were evaluated. Results showed that 6 months after implantation activity around the lesser trochanter and prosthesis shaft became insignificant. Activity around the acetabulum, greater trochanter, and prosthesis tip stabilized approximately 2 years after surgery; approximately 10% of patients in the study had persistent activity in these areas. Familiarity with this normal progression is fundamental to interpretation of postoperative bone scans in patients with total hip prosthesis.
Asunto(s)
Prótesis de Cadera , Medronato de Tecnecio Tc 99m , Acetábulo/diagnóstico por imagen , Fémur/diagnóstico por imagen , Humanos , Falla de Prótesis/diagnóstico por imagen , CintigrafíaRESUMEN
We treated fifty-one cases of fracture of the shaft of the humerus with a functional method of treatment consisting of a plastic sleeve, individually molded or prefabricated. It maintained good alignment of the fragments and permitted rapid and uninterrupted osteogenesis. The early introduction of functional activity to the entire extremity appears to provide a desirable physiological environment conducive to rapid healing. Non-unions have not been encountered in nonpathological fractures. Healing time has been rapid, and there has been consistent restoration of motion of all joints prior to the completion of healing. The morbidity was minimum.