Abstract
Instrumentation is advocated for implantation of a unicompartmental total knee replacement because:
Intramedullary instrumentation in the femur and tibia provides highly reliable alignment of the implants and extremities.
Resection of the peripheral rim of the tibia doesn’t compromise primary fixation or later revision.
Results of a laboratory study published in 1992 revealed that intramedullary instrumentation accurately and reliably restored the knee to correct alignment and kinematics. In five adult human cadaveric lower extremities, anteroposterior radiographs were used to evaluate valgus angle and position of the center of the knee relative to the mechanical axis of the lower extremity. Intramedullary instrumentation returned the knee to normal alignment in all cases. The greatest valgus angle change was 3°, and the position of the center of the knee relative to the mechanical axis was not significantly altered. In five fresh-frozen adult knee specimens, kinematics were evaluated and found to follow the predicted pattern of normal stability in extension. Slightly less varusvalgus laxity was seen at 30°, 45°, and 60°.
A review of results obtained with unicompartmental total knee replacement reveals that excellent alignment and long-term fixation have been achieved and maintained over the past 10 years.
The abstracts were prepared by Mrs Dorothy L. Granchi, Course Coordinator. Correspondence should be addressed to her at PMB 295, 8000 Plaza Boulevard, Mentor, Ohio 44060, USA.
