The Impact of Scaphoid Malunion on Carpal Motion: An In-Vitro Analysis.

The clinical significance of scaphoid malunion is debated and its effect on wrist kinematics is poorly understood. Alterations to scaphoid morphology in other pathologies result in significant sequelae and arthrosis. By understanding the impact of scaphoid malunion on carpal kinematics, better insight can be garnered to inform models of wrist motion and clinical treatment of this injury.

The effect of four-corner fusion and proximal row carpectomy on uniplanar and multiplanar wrist motion: A biomechanical study.

Purpose: To compare changes in wrist kinematics after scaphoidectomy and four-corner fusion (4CF), and proximal row carpectomy (PRC).

Methods: Six cadaveric specimens underwent flexion-extension, radial-ulnar deviation and circumduction in an active motion wrist simulator. Native state, "anatomic 4CF", "radial 4CF", and PRC were compared.

The Effect of Forearm Position on Wrist Joint Biomechanics.

Purpose: All active motion wrist joint simulators have been designed to simulate physiologic wrist motion; however, a main difference among them is the orientation of the forearm (horizontal or vertical with respect to gravity). Moreover, the effect of forearm orientation on experimental results has yet to be quantified, but it may be an important variable. Thus, the purpose of this study was to determine the effect of forearm orientation on wrist kinematics and contact mechanics.

A Biomechanical Evaluation of the ECRL Tenodesis for Reconstruction of the Scapholunate Ligament.

Purpose: Reconstruction of the scapholunate ligament (SLL) in the setting of dynamic instability remains a surgical challenge, with lack of consensus on the best reconstructive procedure. Reconstruction of only the dorsal component may lead to volar gapping and abnormal wrist kinematics. This cadaveric active motion simulation study determined whether scapholunate (SL) motion, angulation, and contact are restored following open reconstruction using the extensor carpi radialis longus (ECRL) tenodesis, which reconstructs both the volar and the dorsal SLL components.

The role of biceps loading and muscle activation on radial head stability in anterior Monteggia injuries: An in vitro biomechanical study.

Introduction: Little evidence-based information is available to direct the optimal rehabilitation of patients with anterior Monteggia injuries.

Purpose Of The Study: The aims of this biomechanical investigation were to (1) quantify the effect of biceps loading and (2) to compare the effect of simulated active and passive elbow flexion on radial head stability in anterior Monteggia injuries.

Study Design: In vitro biomechanical study.

The Impact of Scaphoid Malunion on Radioscaphoid Joint Contact: A Computational Analysis.

Purpose: The clinical relevance of scaphoid malunion is controversial because the biomechanical sequelae remain poorly understood. In this computational study, the effect of increasing scaphoid malunion on radioscaphoid joint contact was assessed.

Methods: Six computational wrist models of active wrist flexion-extension were used to examine 6 scaphoid malunions of varying severities.

Effect of ulnar angulation and soft tissue sectioning on radial head stability in anterior Monteggia injuries: an in vitro biomechanical study.

Background: Radial head instability continues to be a challenge in the management of anterior Monteggia injuries; however, there is a paucity of literature on the factors that contribute to this instability. The aim of this biomechanical investigation was to examine the effects of ulnar angulation and soft tissue insufficiency on radial head stability in anterior Monteggia injuries.

Methods: Six cadaveric arms were mounted in an elbow motion simulator.

An In Vitro Study to Determine the Effect of Ulnar Shortening on Distal Forearm Loading During Wrist and Forearm Motion: Implications in the Treatment of Ulnocarpal Impaction.

Purpose: To evaluate the effect of ulnar shortening on distal forearm loading following simulated dynamic motion.

Methods: Ulnar shortening was simulated using a custom-built adjustable implant to simulate up to 4 mm of ulnar shortening (-4 mm) in 9 cadaveric extremities. Load cells were placed in the distal ulna and radius to quantify axial loading.

Effect of Radial Lengthening on Distal Forearm Loading Following Simulated In Vitro Radial Shortening During Simulated Dynamic Wrist Motion.

Purpose: To evaluate the effect of radial length change on distal forearm loading during simulated dynamic wrist motion.

Methods: A custom-built adjustable radial implant was used to simulate up to 4 mm of distal radius shortening (-4 mm) and 3 mm of lengthening (+3 mm). Load cells were placed in the distal radius and ulna in cadavers to measure their respective axial loads.

Carpal Kinematics following Sequential Scapholunate Ligament Sectioning.

 The scapholunate ligament (SLL) is the most commonly injured intercarpal ligament of the wrist. It is the primary stabilizer of the scapholunate (SL) joint, but the scaphotrapeziotrapezoid (STT) and radioscaphocapitate (RSC) ligaments may also contribute to SL stability. The contributions of SL joint stabilizers have been reported previously; however, this study aims to examine their contributions to SL stability using a different methodology than previous studies.

An Anthropometric Assessment of the Proximal Hamate Autograft for Scaphoid Proximal Pole Reconstruction.

Purpose: Fragmentation of the scaphoid proximal pole secondary to avascular necrosis presents a difficult reconstructive problem. This anthropometric study assesses the utility of the ipsilateral proximal hamate for complete osteochondral scaphoid proximal pole reconstruction.

Methods: Twenty-nine cadaveric specimens underwent computed tomography scanning and 3-dimensional reconstruction of the carpus and distal radius.

The Effect of Dorsally Angulated Distal Radius Deformities on Carpal Kinematics: An In Vitro Biomechanical Study.

Purpose: The purpose was to quantify the effect of distal radius dorsal angulation (DA) on carpal kinematics and the relative roles of the radiocarpal and midcarpal joints during wrist motion.

Methods: Six cadaveric specimens (69 ± 17 y) were mounted at 90° elbow flexion in a custom wrist motion simulator. The wrist was guided through planar passive flexion and extension motion trials (∼ 5°/s).

Biomechanical Evaluation of Carpal Kinematics during Simulated Wrist Motion.

 Flexion and extension of the wrist is achieved primarily at the radiocarpal and midcarpal joints. Carpal kinematics have been investigated, although there remains no consensus regarding the relative contribution of each bone to wrist motion.  To determine the kinematics of the scaphoid, lunate, and capitate during unconstrained simulated wrist flexion/extension and to examine the effect of motion direction on the contribution of each bone.