Needle versus Forceps Technique in Ultrasound-Guided Synovial Biopsy of the Knee Joint

Objectives: Ultrasound-guided synovial biopsy is increasingly applied in rheumatology. Usually forceps- or needle-based techniques are used. So far there has been no direct comparison of different devices regarding their suitability in high resolution musculoskeletal ultrasound (hrMSUS)-guided synovial biopsy. Methods: A core needle biopsy (Quickcore, Cook Medical, Bloomington, IN, USA), an anterograde arthroscopy forceps (Karl Storz GmbH, Tuttlingen, Germany), a retrograde forceps (Retroforce, Karl- Storz GmbH Tuttlingen, Germany) and an convexly shaped integrated core needle system (Synovex, Hipp Medical, Kolbingen, Germany) were tested for ultrasound-guided synovial biopsy of the suprapatellar recess in cadaver knee joints. Four senior rheumatologists scored each intervention from 0-5 regarding the following characteristics: visualization, handiness, accuracy, synovial tissue yield, invasiveness and overall suitability. Each intervention was recorded as static images and video clips. Results: In all devices, enough representative synovial tissue was obtained and the instruments were all well visualized by hrMSUS. Core needle biopsy and the integrated needle system were best visualized due to their horizontally shaped closing mechanism. The core needle obtained a high yield of superficial synovial tissue and was the least invasive procedure. Despite handiness and accuracy were higher in the forceps instruments, overall suitability for hrMSUS -guided synovial biopsy was rated highest for the core biopsy needle. Conclusion: Technically, all of the tested devices can be used for hrMSUS-guided synovial biopsy. Core needle biopsy seems to be most suitable for this intervention due to a low invasiveness, good visualisation and optimal yield of superficial synovial tissue. Keywords: Synovial Biopsy; Ultrasound; Ultrasound-Guided; Forceps; Needle; HrMSUS; Core Biopsy; Retrograde Biopsy; Synoviti