Evaluation of lower extremity alignment in football players by magnetic resonance imaging and investigating the effects of alignment on isokinetic strength

Objective: The aim of this study was three-fold; i) to evaluate the lower extremity alignments in football players with genu varum by magnetic resonance imaging (MRI), ii) to determine the mechanisms underlying the malalignment and the factors contributing to them, and iii) to investigate the relationship between lower extremity alignment and isokinetic strength. Method: Thirty-six elite youth football players were divided into two groups as genu varum group (GVG) and control group (KG) considering the tibiofemoral joint distance differences. Knee extension/flexion and hip abduction/adduction isokinetic strength were tested at 60°/sn and 180°/sn. Anatomical measurements of lower extremity alignment were obtained by whole leg MRI. To evaluate the statistical differences between the groups, the independent sample t-test was applied. A logistic regression model was constructed to determine whether the independent variables are risk factors in the development of genu varum. Results: While varus knee alignment increased mechanical axis deviation and mechanical lateral distal femoral angle, it decreased mechanical lateral proximal femoral angle (mLPFA), medial proximal tibial angle, lateral distal tibial angle (LDTA) and knee joint alignment angle. Furthermore, a one-degree increase in mLPFA in the dominant leg increases the genu varum odds by 2.17 times, while a one-degree increase in LDTA in the non-dominant leg increases the genu varum odds 1.90 times. Conclusion: In football players, the underlying mechanisms of genu varum differs for the dominant and non-dominant legs. This study points out that the femur for the dominant leg and the tibia for the non-dominant leg may play a significant role in the development of the varus knee alignment.