Proximal tibial anthropometry in the Iranian population and its implications for custom total knee prosthesis design

Total knee arthroplasty is a spreading surgery, mainly indicated in severe osteoarthritis patients. The anthropometric features of the prosthesis are one of the main factors affecting the surgery outcome, which varies among different races and genders. Challenges arise when prostheses are poorly matched, leading to suboptimal results and increased revision rates. This study aims to quantify proximal tibial dimensions for ethnically tailored prosthesis design of the Iranian population. All adult candidates for total knee arthroplasty were enrolled in this study. A surgical blade of 38 mm in length is placed on the resected surface of the proximal tibia in all patients, acting as a scale. The trained operating room technician takes a high-quality picture of the area using a camera. Photographs of the proximal tibial cut, removed during the surgery, were analyzed to extract its anthropometric features. AutoCAD software measured the anteroposterior (AP) length, mediolateral (ML) length, and 18 lengths parallel to the AP length for a more precise representation of the proximal tibial morphology. Overall, 110 patients were enrolled in this study with a mean age of 64.94 (± 7.57). The mean mediolateral (ML) and medial anteroposterior (AP) lengths were 71.03 (± 4.58) and 41.71 (± 4.48) mm, respectively. The mean AP length of women and men were 41.17 ± 4.03 mm (95% CI [40.39, 41.95]) and 48.48 ± 4.59 mm (95% CI [45.30, 51.66]), respectively. The AP length was also significantly different between the two limbs, but not the ML. This study provides baseline anthropometric data for the proximal tibia in the Iranian population, highlighting gender and limb asymmetry variations that significantly influence proximal tibial dimensions. These findings offer critical insights for developing ethnically tailored and gender-specific prostheses, potentially improving implant fit, reducing revision rates, and enhancing overall surgical outcomes.