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Background: The first dorsal interosseous muscle is crucial for abduction and stabilization of the index finger during pinch grip. A 56-year-old right hand dominant male sustained a traumatic injury of his right first dorsal interosseous muscle due to right index finger hyperextension during a fencing competition. On examination, there was scissoring of his right index finger dorsal to his middle finger. Intraoperative findings showed rupture of the first dorsal interosseous tendon from its muscle belly. Materials and methods: While different techniques are available, such as tendon transfer of the extensor indicis proprius, the use of a free palmaris longus tendon graft to reconstruct the first dorsal interosseous muscle has yet to be described in existing literature. This case report describes this innovative method and its outcomes. Results: 8 months after surgery, the patient could easily achieve index finger abduction and full active extension at the metacarpophalangeal joint (MCPJ) and interphalangeal joint (IPJ) without pain. Scissoring between his right index and middle fingers was not present. Key and tip pinch grip strengths in the affected hand were 4.5kg. No functional limitation was reported post-reconstruction and the patient has resumed fencing. Conclusions: Our reported case is the first to use palmaris longus (PL) tendon as a standalone, free tendon graft in FDI reconstruction and shows favourable outcomes. We demonstrated that a free PL tendon graft can adequately restore pinch strength and provide stability during index finger abduction without complications.

Objective: Tendinous mallet finger injuries are normally treated conservatively by finger splinting, whereby the injured finger is immobilised in extension to allow the ruptured extensor tendon to heal. However, current splints including the Stack and Zimmer reported high failure rates of almost 50 %. Reasons are attributed to poor splint fit, skin complications and discomfort which cause non-compliance to splint regimens. To address the above mentioned issues, we designed and developed a 3D printed adjustable and customised finger splint. Participants and interventions: The 3D printed finger splint, Zimmer and Stack splint were worn by 24 healthy volunteers on their middle fingers for 24 h. Main outcome measures: The finger extension angle, splint fit, splint comfort and skin maceration were assessed via angle measurement and subjects’ feedback using a questionnaire. Results: The 3D printed finger splint was capable to maintain the distal interphalangeal joint at an extended angle of 8.1° However, 70.8 % of the subjects reported that the 3D printed finger splint shifted or came off wholly during 24 h of wear. This proportion is higher compared to the Zimmer (45.8 %) and the Stack (37.5 %). While 91.7 % of the subjects were satisfied with the ease of wearing and removing the 3D printed finger splint, subjects experienced difficulty performing work and washing activities owing to the design and material. Conclusion: Our proposed design fulfils its function of holding the fingertip in extension and improves ease of application. The design of 3D printed finger splint could be further refined to provide better splint fit and comfort, so as to achieve better treatment compliance.

Injuries within the peripheral nervous system (PNS) lead to sensory and motor deficits, as well as neuropathic pain, which strongly impair the life quality of patients. Although most current PNS injury treatment approaches focus on using growth factors/small molecules to stimulate the regrowth of the injured nerves, these methods neglect another important factor that strongly hinders axon regeneration—the presence of axonal inhibitory molecules. Therefore, this work sought to explore the potential of pathway inhibition in promoting sciatic nerve regeneration. Additionally, the therapeutic window for using pathway inhibitors was uncovered so as to achieve the desired regeneration outcomes. Specifically, we explored the role of Wnt signaling inhibition on PNS regeneration by delivering Wnt inhibitors, sFRP2 and WIF1, after sciatic nerve transection and sciatic nerve crush injuries. Our results demonstrate that WIF1 promoted nerve regeneration ( p

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

Studies on carpal bone kinematics have been conducted before. However, fewer have been done to investigate the synovial fluid kinematics in the scapholunate joint during repetitive wrist movements. We hypothesize that such repetitive wrist movements, i.e., ulnar deviation, could potentially cause the synovial fluid pressure to change accordingly. The objective of this study is to conduct an experimental study to measure synovial fluid pressure changes at the scapholunate joint of a cadaveric hand (n = 1) under repetitive ulnar deviation. A cadaveric hand with the elbow intact was mounted on a custom-made motion simulator at neutral position and the wrist was moved passively towards ulnar deviation. Intact synovial fluid was extracted from the scapholunate joint with the aid of an ultrasound. Hylan GF-20 (Synvisc, USA) was then injected till its synovial fluid cavity was completely filled. The used needle was then connected to a pressure transducer via a rigid tube primed with saline solution. The synovial fluid pressure was measured continuously when the cadaveric wrist was moved 20◦ towards ulnar deviation at 60 cycles per minute. Two independent sets of real-time data were recorded for 15 sec using a Data Acquisition system. The average magnitude of synovial fluid pressure from each dataset was calculated. The synovial fluid pressure change in the scapholunate joint was 174.7 Pa (± 26.4). The changes in pressure over time corresponded to the neutral to maximum ulnar deviation positions of the hand, suggesting the presence of synovial fluid pressure changes induced by the wrist movements. Clinically, we postulate that the synovial fluid pressure generated during ulnar deviation may weaken the scapholunate interosseous ligament after a prolonged period of repetitive wrist motion. [ABSTRACT FROM AUTHOR]