Statistical Analysis of the Patellar Thickness in Adults by MRI

Kim, Myung Ho; Yoo, Moon Jib; Seo, Joong Bae; Park, Hee Gon; Shim, Shang Ho

Abstract

PURPOSE
To provide information on the thickness of the patella in Korean adults and to provide a standard for the selection of a proper patella implant in total knee arthroplasty. MATERIALS AND METHODS: From October 2002 to June 2004, the patellar thickness was measured by MRI in 165 knees. The mean age of the patients was 29 years (20-39 years). Patients with either patellar fractures or deformities were excluded. Of the knees included in this study, 54 knees had meniscal injuries, 53 had cruciate ligament injuries, 24 had knee contusions, and 17 had other disorders. The remaining 17 knees were normal. The measurements were taken in the axial and sagittal images of the MRI scans. The maximum distance in millimeter between the anterior cortex of the patella and the surface of the articular cartilage was measured to the first decimal place. The relationship between the patellar thickness and gender, weight and height was also analyzed. RESULTS: The average patellar thickness on the axial image was 23.8 (SD 1.4) mm in males and 21.7 (SD 1.4) mm in females. The measurement estimated in the axial image was not significantly different from that in the sagittal image. The patellar thickness in males was significantly thicker than in females (p<0.01). There was a significant correlation between the patellar thickness and both the body weight and height (p<0.01). CONCLUSION: The average patellar thickness in Korean adults was 23.8 mm in males and 21.7 mm in females. The patella was thicker in males than in females. Moreover, the patellar thickness was proportional to the height and weight of each individual.