Could Koehler-Freiberg’s Disease be Caused by Biomechanical Factors?

Koehler-Freiberg’s disease, an idiopathic necrosis of the metatarsal head, most commonly occurs in the 2nd, sometimes in the 3rd and relatively seldom in the other rays of the foot. Investigations regarding the possible causes of the disorder have led to an enquiry into the biomechanics of the metatarsophalangeal (MP) articulations. A search through the available literature did not reveal any information that could be directly applied and therefore a series of experiments were performed to determine a) the ground reaction on the MP joints and on the toes, b) the direction of the flexors and other tendons that cross the joint which might be responsible for the force acting between the toes and the ground, c) the geometry of the joint surfaces and finally, d) the force crossing the joint between the head of the metatarsal and the corresponding phalangeal bearing surface. It is shown that the force per unit area, or specific loading, of the MP joint of the 2nd ray could amount to about twice that which occurs in the same articulation of the great toe. This might well explain the higher occurance rate of osteonecrosis observed in the 2nd ray compared to that in the 1st. Furthermore, it is shown that the resultant joint force in the MP joint of the 2nd ray is more dorsally directed than that of the 1st, which coincides very well with clinical observation.