AN IN-VITRO OSTEOTOMY METHOD TO EXPOSE THE MEDIAL COMPARTMENT OF THE HUMAN KNEE

This study was conducted to validate a new in vitro method to expose t he medial compartment of the knee to be used in subsequent studies aim ed at examining the load bearing capabilities of medial meniscal allog rafts. The new method involves an osteotomy and reattachment of the me dial femoral condyle. The primary hypothesis was that the new method d oes not alter tibio-femoral contact pressure and area. To validate thi s method, the baseline contact pressure of the intact medial compartme nt was measured using a new nondestructive procedure for inserting pre ssure pressure measurement into the intact medial hemijoint. A seconda ry and related hypothesis was that incising the coronary ligament, a d estructive method used by previous investigators to position pressure measurement film, alters the normal tibio-femoral contact pressure. To test these hypotheses, Fuji Prescale pressure-sensitive film was used to measure both tibio-femoral contact pressure and area within the me dial compartment of the (1) intact knee, (2) the knee after osteotomiz ing and reattaching the medial femoral condyle and (3) the osteotomize d knee with an incised coronary ligament, using seven cadaver specimen s. Measurements were taken at a compressive load of approximately two times body weight with the knee in 0, 15, 30, 45 deg of flexion. No si gnificant differences between the intact and osteotomized knee were de tected Likewise, no significant differences were observed between the osteotomized knee and the osteotomized knee with an incised coronary l igament. These results confirm the utility of the new method in exposi ng the medial compartment for manipulation and placement of medial men iscal allografts in future studies examining the load-bearing characte ristics of meniscal allografts.