Intraobserver and Interobserver Reliability of the Peritubercle Lucency Sign in Slipped Capital Femoral Epiphysis

Area of Science:

• Orthopaedic Surgery
• Radiology
• Pediatric Medicine

Background:

• The peritubercle lucency sign, an enlargement of the metaphyseal socket, is a potential predictor of contralateral slipped capital femoral epiphysis (SCFE).
• Assessing the reliability of this sign is crucial for its clinical application in patients with unilateral SCFE.

Purpose of the Study:

• To evaluate the intraobserver and interobserver reliability of detecting the peritubercle lucency sign on radiographs.
• To determine the consistency of the peritubercle lucency sign's interpretation among pediatric orthopaedic surgeons.

Main Methods:

• Thirty-five radiographs were reviewed by 6 fellowship-trained pediatric orthopaedic surgeons on two separate occasions.
• Radiographs were presented in a randomized order, and surgeons indicated the presence or absence of the peritubercle lucency sign.
• Statistical analysis, including percent agreement and kappa (κ) values, was used to assess reliability.

Main Results:

• Average intraobserver agreement was 74.8% (κ = 0.508), indicating moderate reliability.
• Interobserver agreement was low, with overall percent agreement at 29% and an average κ value of 0.45.
• Significant variability was observed in the detection of the peritubercle lucency sign between different reviewers.

Conclusions:

• The peritubercle lucency sign demonstrates only modest intraobserver and interobserver reliability.
• Its use in predicting contralateral SCFE should be combined with other clinical factors.
• Refining the definition of the peritubercle lucency sign may enhance its diagnostic value and consistency.