scholarly journals Effect of Surrogate Surface Compliance on the Measured Stiffness of Snowboarding Wrist Protectors

Proceedings ◽  
2020 ◽  
Vol 49 (1) ◽  
pp. 84
Author(s):  
Gemma Leslie ◽  
Weizhuo Wang ◽  
Keith Winwood ◽  
Chris Liauw ◽  
Nick Hamilton ◽  
...  

Wrist injuries have been reported to account for 35%–45% of snowboarding injuries. Snowboarding wrist protectors are designed to limit impact forces and prevent wrist hyperextension. The absence of a standard for snowboarding wrist protectors makes it hard to identify models offering an adequate level of protection. Wrist surrogates are well suited for testing and benchmarking wrist protectors. This study investigated the effect of introducing a soft tissue simulant onto an otherwise stiff wrist surrogate on the bending stiffness of snowboarding wrist protectors. A compliant surrogate (stiff core and 3 mm thick silicone layer) and a comparable stiff surrogate were fabricated. Two snowboarding wrist protectors were tested on each surrogate, under three strapping conditions, following a bend test to ~80° wrist extension. The introduction of a compliant layer to the wrist surrogate gave higher torque values for a given wrist extension angle, increasing protector effective stiffness, relative to a rigid surrogate.

2021 ◽  
Vol 5 (4) ◽  
pp. 488-490
Author(s):  
Colin Jorgensen ◽  
Steve Christos

Case Presentation: A 17-year-old male presented to the emergency department (ED) due to trauma to the right hand and wrist after punching a locker at school. He had significant soft tissue swelling. Radiographs demonstrated intra-articular metacarpal fractures with associated carpometacarpal dislocations. The dislocation was reduced bedside in the ED and ultimately underwent closed reduction surgical management with orthopedic surgery. Discussion: Metacarpal fractures result from high-force impact injuries and account for 30-40% of all hand injuries. The most common sites of second through fifth metacarpal fractures are at the neck and the shaft, with the majority involving the fifth metacarpal neck (commonly coined “boxer’s fractures”). Carpometacarpal (CMC) dislocations are a rare injury associated with high-force impact trauma to the wrist. These injuries account for as little as 1% of all acute hand and wrist injuries. Carpometacarpal dislocations are often difficult to diagnose on physical examination due to significant soft tissue swelling, and they can easily be missed on anterior-posterior views of the hand. Lateral and oblique plain radiograph views are essential in the diagnosis as they are more likely to show dislocations. Despite appropriate plain radiographic views, subtle CMC dislocations may be difficult to discern dependent on the level of dislocation or subluxation and overlapping of joints. These injuries are rare due to otherwise highly stable ligamentous and muscular attachments within the wrist. Because of these attachments, dislocations are often associated with concomitant metacarpal fractures.


Hand Surgery ◽  
1998 ◽  
Vol 03 (01) ◽  
pp. 41-45
Author(s):  
Kazuhiro Masada ◽  
Takeshi Fuji ◽  
Satoru Fujita

A new stabilisation technique has been developed by the authors for the prevention of instability of the distal ulna after performance of Bower's hemiresection-interposition technique in rheumatoid patients, is described. This technique consists of the transfer of the extensor carpi ulnaris over the dorsal aspect of the distal ulna and suturing it to the soft tissue over the distal ulna. Operation was performed in 16 rheumatoid patients with 20 wrist joints. The results were evaluated in terms of both subjective (pain during rotation, pain on compression of the ulna) and objective evaluations (wrist/forearm range of motion, grip strength). After the operation, the pain almost disappeared in all but two cases which had insufficient bone excision. Wrist extension/flexion and pronation/supination improved after operation. Average grip strengths also improved. None of the cases showed instability of the distal ulna after the operation. Wrist extension strength did not decrease after operation in spite of tenodesis of the extensor carpi ulnaris. This technique is simple and useful for prevention of instability of the distal ulna after hemiresection-interposition technique has been carried out in rheumatoid patients.


2006 ◽  
Vol 25 (6) ◽  
pp. 775-787 ◽  
Author(s):  
Marianne J.R. Gittoes ◽  
Mark A. Brewin ◽  
David G. Kerwin

Author(s):  
Caroline Adams ◽  
Tom Allen ◽  
Terry Senior ◽  
David James ◽  
Nick Hamilton

The wrist is a common injury site for snowboarders who often fall onto an outstretched hand. Wrist protectors are worn by some snowboarders to prevent wrist injuries by attenuating impact forces and limiting wrist extension. This paper presents a bespoke pendulum test device for impacting wrist protectors when fitted to a wrist surrogate. The rig can replicate injury risk scenarios, while measuring temporal forces and wrist extension angles. Results from testing 12 snowboarding wrist protectors are presented, including differences in peak vertical force, the time to reach this peak, and energy absorption between products. When compared to an unprotected surrogate, all 12 products lowered the peak force by at least 24% and increased the time to reach this peak by at least 1.8 times. Due to the severity of the load case employed, none of the products lowered the impact force below 2.8 kN, which is the value presented in the literature to fracture a cadaveric wrist. The developed rig could be used to support the development of new wrist protectors, as well as the development of finite element models for predicting wrist protector performance.


1991 ◽  
Vol 113 (4) ◽  
pp. 366-374 ◽  
Author(s):  
S. N. Robinovitch ◽  
W. C. Hayes ◽  
T. A. McMahon

A major determinant of the risk of hip fracture in a fall from standing height is the force applied to the femur at impact. This force is determined by the impact velocity of the hip and the effective mass, stiffness, and damping of the body at the moment of contact. We have developed a simple experiment (the pelvis release experiment) to measure the effective stiffness and damping of the body when a step change in force is applied to the lateral aspect of the hip. Results from pelvis release experiments with 14 human subjects suggest that both increased soft tissue thickness over the hip and impacting the ground in a relaxed state can decrease the effective stiffness of the body, and subsequently reduce peak impact forces. Comparison between our fall impact force predictions and in-vitro measures of femoral fracture strength suggest that any fall from standing height producing direct, lateral impact on the greater trochanter can fracture the elderly hip.


Author(s):  
Patrick Wheeler ◽  
Nicholas Peirce

Hand and wrist injuries represent a considerable challenge for sports physicians and musculoskeletal practitioners. The anatomy is complex and the consequences of minor injury, which are sometimes difficult to assess with routine clinical examination, can have significant impact on function (Hodgkinson et al. 1994...


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