The Length of the Patellar Tendon in Normal Adults

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.

Factors Affecting the Range of Motion after Revision Total Knee Arthroplasty

PURPOSE: We aimed to analyze the clinical results and investigate the factors that affect the range of motion (ROM) after revision total knee arthroplasty. MATERIALS AND METHODS: We measured the range of motion from 61 knees of 55 patients who underwent revision total knee arthroplasty using the Nexgen(R) LCCK and we investigated the factors affecting the postoperative ROM, including age, the body mass index (BMI), the preoperative ROM, deformity, causes of revision (septic vs. aseptic) and the type of polyethylene inserts (constrained vs. posterior-stabilized). The clinical results and radiographic findings were assessed using the American Knee Society Score and the roentgenographic method of the American Knee Society. RESULTS: The mean range of motion was improved from 113.7degrees to 127.2degrees. The preoperative ROM (p=0.000) and diagnosis (p=0.006) significantly influenced the postoperative ROM, yet age (p=0.386), BMI (p=0.054), deformity (p=0.218) and the type of polyethylene insert (p=0.195) were not related to the postoperative knee ROM. The American Knee Society Knee Score and Function Score on average was improved from 31.7 and 27.9 points to 86.7 and 64.7 points, respectively. CONCLUSION: The range of motion and clinical results were satisfactory after revision total knee arthroplasty using the Nexgen(R) LCCK, and the important factors affecting the range of motion after operation were the preoperative ROM and the causes of revision. The range of motion after arthroplasty using the constrained type polyethylene insert was not inferior to that using the posterior-stabilized insert.