The long-term prognosis of Legg-Calvé-Perthes disease: a historical prospective study with a median follow-up of forty one years.

Purpose: The purpose of this study is predicting the clinical and radiological long-term outcome and identifying prognostic factors of Legg-Calvé-Perthes disease (LCPD) in Catterall 2 and 3 hips.

Methods: Sixty hips (59 patients) were diagnosed with LCPD between 1959 to 1974 and were followed prospectively. Forty-two of these 60 hips were classified as Catterall 2 or 3. In 2002, 33 hips (32 patients) with Catterall type 2 or 3 were evaluated clinically and radiographically. In 2010, 27 hips (26 patients) were re-evaluated.

Results: In 2002, 15 hips had Catterall 2 type LCPD and 18 hips Catterall 3. Twelve of the 33 hips (36%) had signs of osteoarthritis. In 2010, 14 hips were classified as Catterall 2 and 13 hips as Catterall 3. Catterall 2 hips had a significantly better Harris Hip Score (HHS) (p = 0.001). There were 15 hips (55%) with signs of osteoarthritis.

Conclusion: The long-term prognosis of LCPD Catterall type 2 and 3 is relatively benign. However, more than 50% of the patients will develop signs of osteoarthritis between the 4th and 5th decades. At the latest follow-up a strong increase in the number of cases with osteoarthritis was seen. Sphericity of the femoral head is an important predicting factor in the development of osteoarthritis.