[ATD index in Perthes disease]

Area of Science:

• Orthopedics
• Pediatric Orthopedics
• Radiology

Background:

• Perthes disease affects the proximal femur in children.
• Assessing outcomes and predicting prognosis in Perthes disease is crucial for treatment planning.
• Radiographic parameters like articulo-trochanteric-distance (ATD) and ATD index are used to evaluate hip joint morphology.

Purpose of the Study:

• To estimate the articulo-trochanteric-distance (ATD) and ATD index in patients with Perthes disease.
• To investigate the correlation between ATD and ATD index with age at onset, gender, treatment type, and radiographic classifications (Herring, Stulberg).
• To determine the reliability of ATD and ATD index as prognostic indicators in Perthes disease.

Main Methods:

• Retrospective analysis of 242 patients with Perthes disease who reached skeletal maturity.
• Estimation of ATD using Edgren methods and calculation of ATD index (Perthes site ATD / normal joint ATD).
• Classification of outcomes using Stulberg and Herring classifications; analysis of treatment types and leg length discrepancy (LLD).

Main Results:

• No correlation found between ATD/ATD index and age at onset or gender.
• Both ATD and ATD index decreased with poorer Stulberg classifications.
• ATD and ATD index were significantly lower after surgical treatment compared to non-operative treatment and in patients with LLD.
• Herring group A showed significantly larger ATD and ATD index compared to groups B and C.

Conclusions:

• The ATD index is a more reliable radiological parameter than ATD for assessing Perthes disease outcomes.
• Decreased ATD index correlates with increased femoral head necrosis and poorer Stulberg classification, indicating proximal femoral growth plate dysfunction.
• Surgical treatment resulted in the most significant decrease in ATD index, highlighting its impact on hip morphology.