抄録
When treating patients with secondary osteoarthritis of the hip, it is important to know the typical natural history, and the factors contributing to the progression of osteoarthritis. This is especially true in determining when to proceed to surgery.
We have made studies of several such factors affecting the natural history of prearthrotic patients followed up at our clinic. The subjects of our investigation were 35 patients (49 joints) diagnosed as prearthrosis and observed conservatively for more than five years. From A-P view X-ray films, we determined the CE-angle, the AHI, the Sharp angle and the degree of the femoralhead deformity, and then investigated the load distribution in the joints using a finite element method (FEM) .
Results showed that the progression of osteoarthritis was rare in patients younger than 30. In patients over 30, many progressing cases were seen in those with CE-angles less than 10°, and/or AHI's under 65. Under FEM, an uneven load distribution was observed in progressing cases, leading us to assume that a mechanical instability was present.
