This landmark paper defines the natural history of Legg-Calvé-Perthes disease through two long-term cohort studies. The first study followed 88 patients (99 hips) for an average of 40 years to correlate residual hip deformity with osteoarthritis development. The second followed 68 patients (72 hips) from disease onset to skeletal maturity to identify active-phase predictors of each deformity type.
Prior to this paper, the field used Mose sphericity ratings to judge Perthes outcomes. Long-term follow-up studies kept showing that severely deformed hips often remained surprisingly functional — a paradox the sphericity framework could not explain.
Stulberg resolved it: a deformed but congruent hip (Classes III–IV) protects against arthritis, while a flat head in a normal acetabulum (Class V) is uniquely catastrophic. The acetabulum remodels to match the head when disease strikes early enough. But not when it strikes after age nine.
In practice, this means Class V is your high-risk patient. When you see Perthes onset after age 9 with partial epiphyseal involvement in the anterosuperior quadrant and limited lateral subluxation, be alert. This is the Class V pattern, and these children face hip replacement before age 50.
The Stulberg classification remains the gold standard long-term outcome measure for Perthes disease, supported by subsequent validation (Wiig et al., 2007). It shifted the treatment goal from simply preserving any femoral head to achieving spherical or at minimum aspherical congruency. Which is why containment-based treatment algorithms exist today.
This landmark paper defines the natural history of Legg-Calvé-Perthes disease through two long-term cohort studies. The first study followed 88 patients (99 hips) for an average of 40 years to correlate residual hip deformity with osteoarthritis development. The second followed 68 patients (72 hips) from disease onset to skeletal maturity to identify active-phase predictors of each deformity type.
Prior to this paper, the field used Mose sphericity ratings to judge Perthes outcomes. Long-term follow-up studies kept showing that severely deformed hips often remained surprisingly functional — a paradox the sphericity framework could not explain.
Stulberg resolved it: a deformed but congruent hip (Classes III–IV) protects against arthritis, while a flat head in a normal acetabulum (Class V) is uniquely catastrophic. The acetabulum remodels to match the head when disease strikes early enough. But not when it strikes after age nine.
In practice, this means Class V is your high-risk patient. When you see Perthes onset after age 9 with partial epiphyseal involvement in the anterosuperior quadrant and limited lateral subluxation, be alert. This is the Class V pattern, and these children face hip replacement before age 50.
The Stulberg classification remains the gold standard long-term outcome measure for Perthes disease, supported by subsequent validation (Wiig et al., 2007). It shifted the treatment goal from simply preserving any femoral head to achieving spherical or at minimum aspherical congruency. Which is why containment-based treatment algorithms exist today.