Bilateral Perthes' disease.

Area of Science:

• Orthopedics
• Pediatric Orthopedics
• Pediatric Rheumatology

Background:

• Perthes disease most commonly affects one hip, with bilateral involvement occurring in 8-24% of cases.
• Understanding the differences between synchronous (simultaneous) and metachronous (sequential) bilateral Perthes disease is important for prognosis.

Purpose of the Study:

• To compare the development and outcomes of bilateral Perthes disease in patients with synchronous versus metachronous hip involvement.
• To evaluate the impact of presentation timing on disease severity and treatment outcomes.

Main Methods:

• Retrospective review of 50 patients (41 boys, 9 girls) with bilateral Perthes disease.
• Analysis of conservative and surgical treatment records and radiographic findings.
• Classification of necrosis using Herring and outcomes using Stulberg criteria.

Main Results:

• Synchronous and metachronous presentations occurred in 52% and 48% of patients, respectively.
• The second affected hip showed significantly more severe necrosis (Herring classification) and worse outcomes (Stulberg classification).
• Disease onset in the second hip occurred an average of 14 months after the first.

Conclusions:

• Bilateral Perthes disease, regardless of presentation type, often involves more severe pathology and poorer outcomes in the sequentially affected hip.
• Younger age at onset and less severe initial avascular necrosis correlate with better outcomes in bilateral Perthes disease.
• Physicians must consider Perthes disease even with similar-appearing hips at presentation, as 19/26 metachronous cases showed identical Reinberg stages.