We examined the correlation between roentgenographic parameters in the early stage of Perthes disease and the results at primary healing.
Sixty-five patients with unilateral Perthes disease were treated conservatively.
At primary healing, 8 patients showed poor results in femoral shape, and 18 showed poor results acetabular shape. Most patients who had poor femoral shape also showed poor acetabular change. Only one patient had poor femoral shape and a good acetabulum.
The results tended to be worse with increasing age of patients and the larger the extent of disease involvement. We designated patients above 8 years of age at diagnosis with Catterall group 3 and 4 involvement and those between 5 and 8 years with group 4 involvement “the at-risk-group”.
The only statistically significant finding from among all the roentgenographic evaluations performed at the fragmentation stage, was between the TDD difference over 3mm and “the at-risk-group”.
In conclusion, patients over 8 years at diagnosis with Catterall group 3 and 4 lesions and those between 5 and 8 years with group 4 staging whose difference of TDD was above 3mm tended to have poor results.