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To define the role of the flexor tendons in trigger finger, a high-resolution ultrasound examination was performed in 20 trigger fingers and 20 normal contralateral digits in three digital postures: full extension, mid-flexion and near-full flexion. Precise measurements of diameter and cross-sectional area of the combined tendon mass were recorded at five clearly defined locations: summit of the metacarpal head, proximal lip of the proximal phalanx (PP) and at 1/8, 1/4 and 1/2 length of the PP. In the normal tendons, there was an anatomical thickening, not previously appreciated at 1/4 length PP, in the region of the FDS bifurcation. This anatomical region moved proximally on finger flexion to the A1 pulley. In trigger fingers, the flexor tendons had greater diameter (sagittal view) and cross-sectional area than the normal side at all locations (p 0.01, p 0.001), with an even greater increase in diameter in the FDS bifurcation area (p 0.001). Trigger fingers also had thicker A1 pulleys (p 0.001). Triggering occurs on flexing the finger when the enlarged combined flexor tendon mass at the specific anatomical region of the FDS bifurcation impacts on the thickened A1 pulley, resisting its excursion.

Multiple imaging modalities have been used to investigate normal wrist mechanics or detect wrist instabilities. While synovial fluid aspiration and biochemical analysis have also been used to study synovial fluid properties in normal and diseased wrist joints, this study aims to measure dynamic changes in intra-articular synovial fluid pressure of the scapholunate joint during repetitive radioulnar deviation. Cadaveric wrist specimens were mounted onto a custom-made motion simulator and moved at 0.5 Hz, from 20° ulnar deviation to 10° radial deviation and back. With guidance of a mini C-arm, a 25-gauge needle was inserted into the scapholunate joint and 0.5 mL of commercially available synovial fluid was injected into the joint. An external pressure transducer was connected to the needle and five sets of intra-articular synovial fluid pressure data were recorded over a period of 8 s. Periodical changes in intra-articular synovial fluid pressure were observed. The mean synovial fluid pressure changes of 4 specimens were 50.7 ± 9.0 Pa, 8.6 ± 3.7 Pa, 49.2 ± 8.8 Pa and 10.1 ± 2.2 Pa. We believe that the periodical changes in intra-articular synovial fluid pressure could be due to the net flow of synovial fluid and hysteresis effect of the scaphoid and lunate movements during radioulnar deviation.

Background The acceptable incidence of thrombophlebitis following intravenous cannulation is 5%, as recommended by the Intravenous Nurses Society guidelines, but publications have reported startling figures of 20% to 80%. Given the frequency of intravenous lines, this presents a potential clinical problem. We aimed to determine the predisposing patient, catheter, and health care-related factors of peripheral vein thrombophlebitis in the upper extremity. Methods In this systematic review, we used a comprehensive search strategy to identify risk factors of thrombophlebitis from inception to May 20, 2019. Studies reporting risk factors of peripheral vein thrombophlebitis of adult patients admitted to the hospital and receiving an intravenous cannulation were included. The Quality of Prognostic Studies tool was used in the assessment for risk of bias to determine the study quality. Results Of the 6910 studies initially identified, 25 were eligible for inclusion. Qualitative syntheses revealed that patient-related factors that confer a higher risk included intercurrent illness, immunocompromised state, comorbidities such as diabetes mellitus, malignancy, previous thrombophlebitis, burns, and higher hemoglobin levels. Catheter-related risk factors included catheter size, duration, and site of insertion. Intravenous antibiotics and potassium chloride predisposed to thrombophlebitis. Cannulation by an intravenous therapy team and more nursing care were associated with a decreased risk. A P-value Conclusion Recognition of the predisposing factors would allow for targeted strategies to aid in the prevention of this iatrogenic infection, which may include closer monitoring of patients who are identified to be vulnerable. Based on this systematic review, we developed an algorithm to guide clinical management. Further research is warranted to validate this algorithm.

Background: Crush injury of nerves is a common condition but the biomechanical integrity of the human peripheral nerve after crushing is unknown. This study aims to investigate the impact of crush injury on human digital nerves based on different compressive forces. Materials and methods: Twenty digital nerves were harvested from three fresh-frozen cadaver hands. The original diameters of proximal, middle and distal end of nerve segment were measured. The midst of each digital nerve was compressed by a customized mechanical system, at 1N, 3N and 5N for 30sec. The diameters were measured again within 1 minute after the nerve crush test was performed. The digital nerve was then subjected to biomechanical test to measure its ultimate tensile strength, stiffness, maximum stress and strain. Deformity of digital nerve was computed based on the diameter of middle nerve segment before and after crush test. Results: No significant difference was found in between groups for ultimate tensile strength (p=0.598), stiffness (p=0.593), maximum stress (p=0.7) and strain (p=0.666). The deformity of nerves under the compression of 1N, 3N and 5N was computed at 72.1%, 54.2% and 45.9%. The effect of compression on the deformity of nerves was statistically significant (p