The subsynovial connective tissue (SSCT) in the carpal tunnel may participate in the origin of carpal tunnel syndrome (CTS), yet material properties of the SSCT have not been well-characterized. We investigated the response of the SSCT to repeated ramp stretch tests. Eight human cadaver wrists were used. The physiological excursion of the flexor digitorum superficialis of the third digit (FDS 3) was measured, starting from a neutral position to maximal flexion of the metacarpophalangeal and proximal interphalangeal joints. The FDS 3 tendon was pulled to 40, 60, 90, and 120% of the physiological excursion. Two ‘ramp stretch’ cycles were performed at every excursion level, except for 120% of excursion, where 3 cycles were performed. The ratio of energy absorbed between the second (E2) and first (E1) ramp-stretch was 0.94 (Std. Dev. = 0.07) for 60%, 0.84 (Std. Dev. = 0.11) for 90%, and 0.68 (Std. Dev. = 0.11) for 120% of the physiological excursion. A significant decrease occurred in energy absorbed after the first ramp-stretch cycle at 90% and 120% of the physiological excursion, which was not seen at 60%. Our data are consistent with a stepwise damage occurring in the SSCT. Furthermore, the damage seems to initiate within the physiological range of tendon excursion. This finding may be important in understanding the pathophysiology of conditions that are associated with SSCT pathology, such as carpal tunnel syndrome.

This study showed a high prevalence of radiographic HOA and a significant relationship between hand pain and the severity of HOA, in addition to erosion.

Necrotising soft-tissue infections (NSTIs) of the upper limb are uncommon, but potentially life-threatening. We used a national database to investigate the risk factors for amputation of the limb and death. We extracted data from the Japanese Diagnosis Procedure Combination database on 116 patients (79 men and 37 women) who had a NSTI of the upper extremity between 2007 and 2010. The overall in-hospital mortality was 15.5%. Univariate analysis of in-hospital mortality showed that the significant variables were age (p = 0.015), liver dysfunction (p = 0.005), renal dysfunction (P < 0.001), altered consciousness (p = 0.049), and sepsis (p = 0.021). Logistic regression analysis showed that the factors associated with death in hospital were age over 70 years (Odds Ratio (OR) 6.6; 95% confidence interval (CI) 1.5 to 28.2; p = 0.011) and renal dysfunction (OR 15.4; 95% CI 3.8 to 62.8; p < 0.001). Univariate analysis of limb amputation showed that the significant variables were diabetes (p = 0.017) mellitus and sepsis (p = 0.001). Multivariable logistic regression analysis showed that the factors related to limb amputation were sepsis (OR 1.8; 95% CI 1.5 to 24.0; p = 0.013) and diabetes mellitus (OR 1.6; 95% CI 1.1 to 21.1; p = 0.038). For NSTIs of the upper extremity, advanced age and renal dysfunction are both associated with a higher rate of in-hospital mortality. Sepsis and diabetes mellitus are both associated with a higher rate of amputation.

Carpal tunnel syndrome (CTS) is a common peripheral entrapment neuropathy of the median nerve at wrist level, and is thought to be caused by compression of the median nerve in the carpal tunnel. There is no standard quantitative reference for the diagnosis of CTS. Grey-scale sonography and sonoelastography (SEL) have been used as diagnostic tools. The most commonly agreed findings in grey-scale sonography for the diagnosis of CTS is enlargement of the median nerve cross-sectional area (CSA). Several authors have assessed additional parameters. "Delta CSA" is the difference between the proximal median nerve CSA at the pronator quadratus and the maximal CSA within the carpal tunnel. The "CSA ratio" is the ratio of CSA in the carpal tunnel to the CSA at the mid forearm. These additional parameters showed better diagnostic accuracy than CSA measurement alone. Recently, a number of studies have investigated the elasticity of the median nerve using SEL, and have shown that this also has diagnostic value, as it was significantly stiffer in CTS patients compared to healthy volunteers. In this review, we summarize the usefulness of grey-scale sonography and SEL in diagnosing CTS.

The subsynovial connective tissue (SSCT) in the carpal tunnel may play a role in the etiology of carpal tunnel syndrome (CTS), yet the material properties of the SSCT remain unclear. Thus, we investigated the mechanical response of the SSCT in a rabbit model. Twenty-four rabbit cadaver paws were used for mechanical testing; two paws were used for scanning electron microscopy (SEM) imaging. After testing normal tendon excursion, the divided third digit flexor digitorum superficialis (FDS) tendon was pulled to displacements of 2, 3.5, 5, or 8 mm, maintained at that position until force decay, and then the process was repeated. Normal excursion of the FDS averaged 4.8 mm. The ratio of the second peak force to the first peak force in the 2 mm group was 0.98 (SD = 0.16), which was significantly higher than the other groups (3.5 mm: 0.74, 5 mm, 0.63, and 8 mm: 0.59; p < 0.05). SEM showed ruptured fibrils in the displaced specimen. The declining force ratio with displacements >2 mm suggests damage to the SSCT within the physiological tendon excursion. These data may be useful in understanding SSCT mechanics in CTS, which is associated with SSCT fibrosis.