The Length of the Patellar Tendon in Normal Adults

ABSTRACT

PURPOSE: This study was conducted to measure the length of the patellar tendon in normal adults and to analyze the effect of several anthropological variables on the patellar tendon length. MATERIALS AND METHODS: The study included 316 knees (278 males, 38 females) that were undergoing anterior cruciate ligament reconstruction with a bone-patellar-bone autograft. The patellar tendon length was measured on the middle 1/3 of the ipsilateral patellar tendon taken during the operation and we analyzed the relationships between the tendon length and age, weight, height and gender using simple correlation tests and linear regression analysis. RESULTS: The mean tendon length was 42.6 mm (range 30~60 mm) and the mean age, mean weight and mean height was 32.7 years, 72.8 kg and 170.2 cm, respectively. There was weak negative correlation between the tendon length and age (Pearson correlation r=-0.187) and weak positive correlation between the tendon length and weight (r=0.288) but there was no significant correlation between tendon length and the body mass index (p=0.282) There was a positive correlation between tendon length and height (r=0.434). There was a significant difference between the males and females for the length of tendon (p<0.001), yet after removing the variance of height, the difference was statistically insignificant (beta=-0.041, p=0.491). The linear regression equation for the patellar tendon length (y, in centimeters) as a function of height (x, in centimeter) can be expressed as y=0.032x1.183. CONCLUSION: The length of the patellar tendon is correlated with height, and a patient's height can predict the length of the patellar tendon.