Which laboratory finding would confirm the diagnosis of slipped capital femoral epiphysis (SCFE)?

• A. Normal joint fluid analysis
• B. X-ray showing femoral head displacement
• C. Positive hip joint aspiration
• D. Elevated serum calcium levels

Answer: (B)

The confirmation of a diagnosis of slipped capital femoral epiphysis (SCFE) is primarily achieved through imaging studies, with X-rays being the key diagnostic tool. In SCFE, the femoral head is displaced due to slippage at the growth plate (the physis). This displacement can be identified through specific radiological changes observed on X-rays.

A typical X-ray for SCFE would show the femoral head being displaced posteriorly and inferiorly relative to the femoral neck. This characteristic appearance of the femoral head indicates that there has been a movement from its usual anatomical position, which is crucial for confirming the diagnosis.

Other options such as joint fluid analysis or hip joint aspiration may provide important information regarding the presence of other conditions affecting the hip joint but do not confirm SCFE. Similarly, elevated serum calcium levels would not be relevant in the context of SCFE as they pertain to metabolic or endocrine issues, not the mechanical displacement seen in this condition. Hence, the X-ray showing femoral head displacement directly correlates with the defining pathology of SCFE, making it the correct choice for diagnosis confirmation.