Subchondral screw fixation of cervical hip fractures: joint congruence studied with combined arthrography and tomography

This study was done to determine whether fixation with the Uppsala internal fixation technique into the subchondral bone of the femoral head in the treatment of cervical hip fractures could lead to elevation of the femoral head cartilage. Combined arthrography and frontal tomography of the hip joint in the plane of the screws was performed. The series consisted of 16 patients. In two of the patients, the tips of the screws had penetrated into the cartilage of the femoral head. In the other 14, the internal fixation was technically correct with the tips of the screws in the subchondral bone. In the two hips with the screws penetrating into the cartilage, the cartilage was slightly elevated. In the hips where the screws were in the correct position, no incongruities or deformity in the cartilage could be detected. Combined arthrography and frontal tomography can, therefore, detect elevation of the cartilage of the femoral head. By placing the screws in the immediate subchondral bone, no elevation of the cartilage of the femoral head surface should occur.