Patella Position in the Normal Knee Joint

Kim, Ik Dong; Ihin, Joo Choul; Lee, Soo Young; Kwon, Koing Woo; Lee, Chang

Abstract

Patella position in the normal knee jolnt has been discussed by many authors such as Boon-Itt 1930, Blumensaat 1938, and Insall 1971. But measure with Boon-Itt's method was so complicated and with Blumensaat's was denied by others due to inefficacy. Insall suggested more simple and clinically applicable method that was based on the fact that patellar tendon is inelastic. Now, we measured 100 healthy Korean knee accordlng to Insall's method. The following results were obtained in the study, 1. The length of the patellar tendon is 4.45 In males, 4.08 In females, and 4.26±0.40 cm. in average. (p<0.001) 2. The length of the patella is 4.51 in males, 4.09 In females, 4.36±0.40 cm. in average. (p<0.001) 3. The length of the patellar tendon (LT) and the dlagonal length of the pattella (LP) are almost same (LT: LP is 0.99 in both males and females, 98% of normal knees are contained within the difference of +20%). Difference above this limit may mean high-riding patella. 4. Blumensaats line on the distal femur doesnt pass the lower pole of the patella but the Iine passes 1 cm. below it in average. 5. The length of the patella (LP) and of the width of the femoral condyles at Blumensaat's line (WCBL) are almost same. When LP is markedly decreased in comparison with WCBL, this case may suggest hypoplasia of the patella. 6. Height of insertion of the patellar tendon (Hl) dlffers among various indlviduals. Its length is cllnically not so significant.