Biomechanics of external fixator of distal radius fracture, a new approach: Mutifix Wrist.

BACKGROUND: The purpose of this study was to assess factors affecting fixator stiffness with a finite element model and an experimental validation with particular attention to a new fixator device named Mutifix Wrist® (NCS Lab srl, Carpi, MO, Italy). MATERIALS AND METHOD: Mechanical tests were carried out to determine the stiffness of the construct with different configurations. The obtained results were compared to those obtained with the Hoffmann II Compact (Howmedica-Osteonics Inc. Rutherford, NJ, USA). Data were sampled at 20 Hz and test speed was 0.05 mm/s. For each loading condition, tests were performed four times. A FEM campaign was also conducted to analyze how geometrical variables (type of configuration and K-wire diameter) affect both stiffness and stress distribution of the fixator. RESULTS: Stiffness, axial displacement, magnitude of the displacement, magnitude and localization of the peak stress of the construct were all analyzed. Axial compression tests showed that the axial displacement reached by the machine actuator when the measured force reached 45 N was 0.56 mm ± 0.13 on average. Magnitude of the displacement along with peak stress magnitude and localization varied through the several configuration tested, but it resulted that the distal pin near the fracture gap was the more stressed one in all cases except those in which the fracture line is crossed. CONCLUSIONS: From the tests performed, it emerged that the addiction of a K-wire provides a construct stiffening and a consequent local stress reduction; while span increase reduces stiffness and increase the local stress. If a K-wire is implanted through the fracture site, the axial stiffness is significantly increased.

Scaphoid fractures with scapholunate ligament involvement: Instability or ligamentous laxity? Role of arthroscopy and pinning.

PURPOSE: Percutaneous fixation of scaphoid fractures often does not allow the evaluation of potential ligamentous lesions. Arthroscopy is an useful tool in the management of scaphoid fractures to visualize potentially associated lesions. With arthroscopic assistance, we often found scapholunate ligament lesions. Our study's aim was to evaluate the role of arthroscopy in the treatment of scaphoid fracture and in particular if the alteration found was a real lesion causing instability or just a paraphysiologic laxity. Furthermore, we evaluated whether the scapholunate joint pinning alters the outcome. METHODS: We performed a retrospective study on 39 patients (33 males and 6 females), with an average age at trauma of 31.2 years (range 15-67), who underwent surgery for scaphoid fractures between 2010 and 2016 in our Center of Hand Surgery. Patients were divided into four groups based on surgical technique and finding of scapholunate lesions. RESULTS: Differences between the four groups analyzed, both in terms of clinical scores and ROM, were not statistically significant. This corroborates the hypothesis that all four treatments are equivalent. CONCLUSIONS: Based on our experience and the literature available, we believe the systematic use of arthroscopy to be useful in patients needing surgical treatment for scaphoid fractures. This is because arthroscopy allows the control of the fracture reduction, screw protrusion evaluation and ligamentous lesions assessment. In cases of partial scapholunate ligament alteration in which no sign of acute lesion is present (hemorrhage and clear rupture), pinning is not necessary since it might just be a paraphysiologic laxity. LEVEL OF EVIDENCE: IV.

Scapholunate interosseous ligament injury in professional volleyball players.

Injuries to the scapholunate interosseous ligament (SLIL) are the most common cause of carpal instability. A SLIL injury typically follows a fall on an outstretched hand, with the wrist in hyperextension, ulnar deviation and intercarpal supination. We hypothesize that repetitive axial loading on the wrist in hyperextension, during the reception and digging motions of volleyball, can lead to functional overloading of the SLIL. To identify patients and to determine the clinical history and surgical treatment performed, we analyzed hospital records, X-rays, electronic databases containing all the operations performed, and image files (including before and after surgery and follow-up). We identified three SLIL injury cases in national volleyball team players, also at the libero position, who were treated at our clinic between 2007 and 2013 for scapholunate instability. Open reduction and Berger capsulodesis was performed in all cases. At a mean follow-up of 3 years (range, 22-50 months), the mean pain level on VAS was 0.3 (range, 0-1) at rest and 1.7 (range 1-2) during sport activities. The mean DASH score was 4 (range 2-5). The mean wrist flexion was 60° (range 55-70°) and extension was 80° (range 75-85°). Given the greater susceptibility of these players for developing a SLIL injury, a high index of suspicion is needed when managing athletes presenting with wrist pain or instability.

Tetraplegia: update on assessment.

The overall assessment in the tetraplegic patient should be comprehensive and detailed. This paper discusses aspects of the medical and physical assessment that normally may go unrecognized but are extremely important in the outcome of the tetraplegic patient. A comprehensive classification also is provided as a new guideline for rehabilitation and surgery. Additionally, the power of [figure: see text] cultural, social, and personal dimensions of disability are illustrated and the importance of these dimensions as they relate to assessment is examined. Finally, the COPM is introduced as an outcome measure capable of crossing cultural [table: see text] boundaries and allowing for the comparison of interventions.