Due to the size and deep position, a complete physical examination of the hip is often difficult. In patients with hip pain or limited motion range, ultrasonography (US) of the hip is widely accepted in the past two decades as a useful diagnostic tool. It is commonly used in children and adults alike.
Calcium pyrophosphate deposition (CPPD) disease is characterized by deposition in the hyaline cartilage, fibrocartilage, and soft tissues of calcium pyrophosphate crystals. The most common CPPD sites are meniscal knee fibrocartilage, femoral condyle hyaline cartilage, shoulder, hip, and ankle cartilage.
According to a preliminary study published in Arthritis Care & Research, ultrasound imaging can be used reliably to identify deposits of calcium pyrophosphate crystal (CPP) in the hip joints of patients with CPPD.
The research was conducted to evaluate the sensitivity and specification. Also, the agreement was carried out between ultrasound imaging and conventional radiography (CR) in the evaluation of hip CPP crystal deposits. A bilateral hip examination was conducted to evaluate the presence of CCP crystal deposits in the acetabularlabrum fibrocartilage and in the hyaline cartilage of femoral head.
The presence of hip CPP crystal deposits on CR was evaluated by two independent radiologists. Fifty consecutive patients with definite CPPD and 40 age/sex/body mass indexed disease controls that had undergone hip CR were enrolled. Calcium pyrophosphate crystal deposits were detected by ultrasound in at least one hip in 45 of 50 patients with CPPD.CPP deposits in the acetabularlabrum fibrocartilage and the femoral head hyaline cartilage more frequently found.
Conventional radiography identified CPP deposits in at least one hip in 43 out of 50 CPPD patients, four out of 40 disease controls, 72 out of 100 hips in CPPD patients, and five out of 80 hips in disease controls. The results provide new evidence supporting the ultrasound imaging as a first-line, sensitive, safe, and reliable imaging technique to detect hip-level CPP crystal deposits.