The following is a summary of “Diagnostic accuracy of hip joint ultrasound for detection of calcium pyrophosphate deposition,” published in the September 2024 issue of Rheumatology by Soto-Fajardo et al.  

 Calcium Pyrophosphate Crystal Deposition (CPPD) disease is a long-term, disabling joint condition. While ultrasound is effective in diagnosing CPPD, its usefulness in detecting CPP crystals in the hip joint remains unclear.   

Researchers conducted a prospective study assessing the accuracy of ultrasound in identifying CPP crystals in the hip joint, comparing its results with histopathology findings.   

They recruited patients over 50 years of age with osteoarthritis scheduled for hip replacement. Ultrasound assessed acetabular fibrocartilage (FC) and femoral head hyaline cartilage (HC) for CPP crystals. Synovial fluid (SF) was analyzed under polarized light microscopy, while a pathologist examined FC and HC samples for crystals using histopathology.   

The results showed that 100 patients were enrolled in the study, with 62% showing hyperechoic areas on ultrasound, suggesting CPPD. Pathological analysis confirmed CPP crystals in 61%. Sensitivity, specificity, positive, and negative predictive values were 90%, 82%, 89%, and 84%, respectively. The area under the curve for ultrasound was 0.86 (95% CI: 0.78-0.94).    

Investigators concluded that ultrasound is a reliable imaging tool with solid diagnostic accuracy for detecting CPPD in the hip joint.  

Source: academic.oup.com/rheumatology/advance-article-abstract/doi/10.1093/rheumatology/keae515/7766116