Development of a New Device for Synovial Biopsies

BACKGROUND: Synovial biopsy is a reliable procedure that permits the identification of specific pathologies. Currently available needles for blind synovial biopsy usually consist of 2 components. We designed a novel 1-piece device for blind and minimal invasive synovial biopsy of the knee joint. METHODS: A convex-shaped trocar with internal sharp plunger at the distal end and a fluid channel was engineered. Synovial biopsy of the suprapatellar recessus of the knee was performed in 8 different cadavers. The intra-articular position of the tip was confirmed by aspiration of prior injected saline fluid. The trocar was levered upward with the open notch of the device facing the anterior wall of the recessus. Then, the punch mechanism was closed and the device removed. Routine histology of the obtained tissue was performed. After the intervention, the joints were prepared for macroscopic inspection of the synovial tissue, including penetration and biopsy sites. RESULTS: Fifteen interventions were performed. In all cases, sufficient synovial tissue was obtained. Mean length of the biopsies was 2.4 mm (range 2.0-4.3 mm) and width was 2.0 mm (range 1.4-2.6 mm). Inside the suprapatellar recessus, the mean distance from the entry site of the device to the biopsy site was 3.8 cm (range 1.1-3.4 cm). Histological analysis confirmed synovial and capsule tissue in all cases. CONCLUSION: This new device is a potentially useful tool for quick synovial biopsy of the knee in the clinical setting.