抄録
Functional reparation of the subtalar joint was analyzed using our newly devised X-ray technique in 64 knees of 43 patients (34 female, 9 male), with an average age of 66 years, suffering from medial Compartmental osteoarthritis. The patient was asked to stand on one leg on a radiolucent rack, and a film cassette was placed behind the heel. The X-ray was focused on the ankle joint at an angle 20 degrees from the horizontal, from anterior to posterior. In this X-ray, the acute angle between the axis of the tibia and the calcaneal tuberosity was named the anterior tibio-calcaneal angle (ATCA) . The femoro-tibial angle (FTA), the angle of tibia vara, talar inclination, tibial inclination and ATCA were measured. ETA had a significant (p<0.001) correlation with tibial inclination (r=0.640), talar tilt (r=0.485) and ATCA (r=0.567), respectively. Because progression of osteoarthritis of the knee causes varus deformity of the knee and tibial inclination, the calcaneus should naturally move to pronation in order to laterally correct this medial shift of the weight-load line in the knee and ankle. This seems to be a compensating mechanism of the human body to prevent an excessive stress concentration on the knee and ankle joints.
