RESECTION SPECIMEN ANALYSIS OF PROXIMAL TIBIAL ANATOMY BASED ON 100 TOTAL KNEE ARTHROPLASTY SPECIMENS

Although it is known that there is some asymmetry of the tibial platea u, most total knee arthroplasty designs currently have a symmetric tib ial component. Using resection specimen analysis of the tibial plateau from 100 total knee arthroplasty specimens, the authors have examined the tibial plateau to further delineate, quantitatively, the medial a nd lateral tibial configuration. Unmagnified radiographs of each of th e specimens were produced. A line was drawn along the mediolateral axi s. The midpoint and points 10, 20, and 30% from the medial and lateral peripheries were then calculated. The average anteroposterior medial 10, 20, and 30% dimensions were 3.79, 4.74, and 5.06 cm, respectively. The average anteroposterior lateral 10, 20, and 30% dimensions were 3 .48, 4.10, and 4.16 cm, respectively. The ratios of the lateral/medial anteroposterior distances at 1O, 20, and 30% from the periphery were 92.10, 86.77, and 82.46%, respectively. A total knee arthroplasty syst em that recognizes the difference in the medial and lateral tibial pla teaus and designs a prosthesis to account for the smaller, lateral tib ial plateau may achieve the goal of maximizing tibial coverage as well as eliminate the problems associated with a symmetric design.