McKeeman Jonathan, DeLeon Ryan, Heckman Daniel
Department of Orthopedic Surgery, St Luke's University Health Network, Bethlehem, Pennsylvania, USA.
Orthop J Sports Med. 2025 Jun 19;13(6):23259671251343811. doi: 10.1177/23259671251343811. eCollection 2025 Jun.
The tibia:femur ratio (TFR) is an anatomic proportion describing the length of the tibia relative to the femur, with an established normative mean of 0.78 in skeletally mature individuals. Variation in TFR affects lower extremity biomechanics, and there is an association between elevated TFR and hip/knee osteoarthritis and patellar instability.
TFR variation may also be associated with anterior cruciate ligament (ACL) injury; thus, the purpose of this study is to determine if the mean TFR in patients with ACL injury is different from the mean normative TFR in the general population.
Cross-sectional study; Level of evidence, 3.
A total of 50 patients with magnetic resonance imaging-confirmed ACL injury underwent full-length lower extremity scanograms. Femoral length was measured from the most superior point of the femoral head to the center point of the medial femoral condyle. Tibial length was measured from the center point of the medial tibial plateau to the center point of the tibial plafond. The TFR was calculated by dividing the tibial length by the femoral length. The mean TFR of the study group was compared with the previously published mean TFR for normative controls with a 2-tailed test.
The mean TFR for the entire cohort of patients with ACL injury was 0.759 (SD, 0.029), which was significantly lower than the mean normative TFR of 0.781 ( = .0001). There were 29 (58.0%) male and 21 (42.0%) female patients. The mean TFR was similar for male (0.760) and female (0.757) patients ( = .77).
Patients with ACL injury demonstrated a significantly lower TFR than the previously published TFR for normative controls, which suggests that an association between TFR and ACL injury may exist. It is possible that decreasing tibial length relative to femoral length alters lower extremity biomechanics in such a manner that places the ACL at risk for injury.
胫股比（TFR）是一种解剖学比例，用于描述胫骨相对于股骨的长度，在骨骼成熟个体中，其既定的正常平均值为0.78。TFR的变化会影响下肢生物力学，并且TFR升高与髋/膝骨关节炎及髌股关节不稳之间存在关联。
TFR变化可能也与前交叉韧带（ACL）损伤有关；因此，本研究的目的是确定ACL损伤患者的平均TFR是否与一般人群的正常平均TFR不同。
横断面研究；证据等级，3级。
共有50例经磁共振成像确诊为ACL损伤的患者接受了全下肢扫描X线片检查。股骨长度从股骨头最上点测量至股骨内侧髁中心点。胫骨长度从胫骨内侧平台中心点测量至胫距关节面中心点。TFR通过胫骨长度除以股骨长度计算得出。研究组的平均TFR与先前公布的正常对照组平均TFR进行双尾检验比较。
整个ACL损伤患者队列的平均TFR为0.759（标准差，0.029），显著低于正常平均TFR的0.781（P = .0001）。有29例（58.0%）男性和21例（42.0%）女性患者。男性（0.760）和女性（0.757）患者的平均TFR相似（P = .77）。
ACL损伤患者的TFR显著低于先前公布的正常对照组TFR，这表明TFR与ACL损伤之间可能存在关联。相对于股骨长度，胫骨长度的减小可能会改变下肢生物力学，从而使ACL面临损伤风险。
