Biomedical subjects

James Benjamin

Publications and source records attributed to James Benjamin.

3 recordsLinked to original sources

PubMed2006

Correcting lateral patellar tilt at the time of total knee arthroplasty can result in overuse of lateral release.

Ninety-nine patients undergoing primary total knee arthroplasty were prospectively evaluated for pre-resurfacing and post-resurfacing patellar thickness and medial patellar liftoff at 30 degrees of flexion without manual pressure on the patella. Regardless of medial patellar liftoff, no lateral releases were performed. Tibiofemoral angles, patellar tilt, and patellar congruence angles were measured preoperatively and postoperatively. There were no patellar subluxations, dislocations, or complications related to the patellofemoral joint. Patellar tilt improved from 7.9 degrees preoperatively to 3.8 degrees postoperatively. Patients with 10 mm or more of intraoperative liftoff improved from 9.9 degrees tilt preoperatively to 6.6 degrees postoperatively. Patients with no intraoperative liftoff had a change from 6.3 degrees to 2.9 degrees . Although the 2 groups were statistically different, the amount of change in alignment was not different between the groups. Patients with medial patellar liftoff at the time of arthroplasty do not appear to require lateral release to yield acceptable postoperative patellofemoral alignment.

Aged↗

PubMed2006

Component alignment in total knee arthroplasty.

Prosthetic component positioning in total knee arthroplasty is a critical determinant of long-term survival of the implant. The goal of component alignment is to recreate the normal mechanical axis of the lower extremity and to achieve a stable, balanced articulation. In addition to component position, it is desirable to select a prosthesis size that, as closely as possible, matches that of the patient. The tibial component is usually placed perpendicular to the longitudinal axis of the tibia in the coronal plane and, depending on implant design, sloped neutral to posteriorly in the sagittal plane. This positioning differs from the normal alignment of the tibial articular surface, which is oriented in slight varus. Because of the change in tibial orientation, the desired femoral component position also differs slightly from the normal anatomic configuration.

Arthroplasty, Replacement, Knee↗

PubMed2003

Knee scores change with length of follow-up after total knee arthroplasty.

Patients undergoing primary total knee arthroplasty (TKA) between 1989 and 1994 were evaluated preoperatively and postoperatively with the Knee Society scoring system at 3 time intervals: 1 to 2 years, 3 to 6 years, and more than 7 years. Knee prosthesis and functional scores improved statistically after TKA. At last follow-up evaluation, a statistically significant decline was found in functional knee scores that was related to an increase in numbers of patients in category C. Progression of arthritis at other sites, especially lumbar spine and hips, and cardiopulmonary problems were the most common cause of limited functional capacity. Women were found to have lower preoperative and postoperative functional scores. Patient weight, body mass index (BMI), and age at surgery showed no correlation with postoperative functional scores. The inclusion of functional categories would appear to be warranted when reporting long-term results of TKA.

Aged↗