Physiopathology of the knee joint after distal iliotibial band transfer

Summary

In an experimental study of 14 cadaver knee joints, the pressure load on the joint surface after distal iliotibial band transfer was measured using Fuji Prescale foils. With an intact anterior cruciate ligament, increases of up to 153% for the average pressure load and of 225% for the total pressure in the lateral compartment were found in relation to the fixation point chosen. At point P3 — slightly dorsal to the insertion of the lateral collateral ligament — the area loaded with maximum pressure increased to six-fold. Fixation at the transition of the lateral femoral condyle to the femoral shaft at the start of the linea aspera was associated with the least pressure increases in both the lateral and the medial compartments. Under all experimental conditions, lateral extra-articular stabilization with fixation at the insertion of the fibular collateral ligament was shown to be associated with significantly higher load increases. While a shift of pressure load to the dorsal third was seen in the lateral compartment, the mid-third remained the focus of the pressure load in the medial compartment. After transection of the anterior cruciate ligament and iliotibial band transfer at the “over-the top” point, a significant shift of pressure towards the medial compartment was seen, while the lateral pressure load decreased. Medially, the area loaded with peak pressure remained constant, while the corresponding area in the lateral joint space showed a highly significant decrease to nearly one-third of normal. After additional bilateral meniscectomy this tendency was even more pronounced. In the lateral compartment no significant changes of pressure load conditions were seen, but the medial compartment showed significant increases in average pressure, total force, and the area loaded with maximum pressure. The results of our investigations suggest that the concept of extra-articular stabilization ought to be revised, as lateral iliotibial band transfer with an intact intra-articular cruciate ligament insertion was associated with a massive increase of pressure in the lateral joint space, while exclusively extra-articular stabilization or an insufficient graft results in additional load on the medial compartment.