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Understanding the stresses on the scapholunate interosseous ligament (SLIL) and its interaction with synovial fluid pressure could be vital to improve wrist treatment for various wrist conditions such as arthritis, sprains and tendonitis. This study investigated the interaction between the intra-articular pressure, specifically the synovial fluid pressure change and the SLIL stresses in a computational model during wrist radioulnar deviation (RUD). Magnetic resonance imaging (MRI) scans were used to acquire the anatomical model of the carpal bones and ligament, while the kinematics of scaphoid and lunate were obtained through dynamic computerized tomography (CT) scans. A two-way fluid-structure interaction (FSI) was used to model the dynamics between the scaphoid and lunate, the SLIL, and the synovial fluid. The synovial fluid pressure change was found to be small (-4.86 to 3.23 Pa) and close to that simulated in a previous work without the SLIL (-1.68 to 2.64 Pa). Furthermore, peaks of maximum fluid pressure were found to trail the peaks of ligament stress. Therefore, it is suggested that the influence of synovial fluid pressure on the ligament in the SLIL model is negligible and simulations of the scapholunate joint could forego fluid-structure interactions. Future studies can instead explore other structures in the carpus that can possibly contribute to the ligament stresses. Clinically, treatments can be targeted at these areas to help prevent or slow the progression of ligament injuries into serious consequences like the degenerative joint disease.

Background: Massachusetts General Hospital (MGH) repair is one of the widely used 4-strand flexor tendon repair techniques. However, it uses two single strand sutures that are each passed twice across the repair site. This is time consuming and may cause imbalance of the load across the repair. We modified the MGH repair by using a looped suture and call it the looped MGH repair. The aim of this study is to compare the strength of the looped MGH repair performed with three different looped sutures against the strength of original MGH repair. Methods: Forty porcine flexors were used for the study. The original MGH repair was performed with Prolene® 4-0. Looped MGH repair was performed with three different loop sutures, Supramid® 4-0, Tendo-Loop® 4-0 and FiberLoop® 4-0. Mechanism of failure, ultimate tensile strength, stiffness, load to 2-mm gap formation and repair time were recorded for comparison. Results: There was no significant difference between the original MGH repair and the looped repair using Supramid® regarding their biomechanical performance. Looped MGH repair using Tendo-Loop® and FiberLoop® showed significantly higher ultimate tensile strength and FiberLoop® had highest 2-mm gap force. All looped MGH repairs required significant less time compared to original MGH repair. Conclusions: Our modification of the MGH repair using a looped Supramid® 4-0 suture took significantly lesser time to perform while providing the same strength as the original MGH repair using Prolene® 4-0. The use of the FiberLoop® 4-0 provided significantly greater strength while taking lesser time.

Concepts of tissue damage from sepsis are rooted in the works of Pasteur regarding colonization by microorganisms, and Lister’s observation of avoiding suppuration by their exclusion. The reactive inflammation has been considered a beneficial defence mechanism. A more complex biology is now unfolding of pathogenic mechanisms with toxins produced by the organisms now being placed in a broad category of virulence factors. Neutrophils are key cells in providing innate immunity and their trafficking to sites of infection results in entry to the extracellular space where they attack pathogens by release of the contents of neutrophil granules and neutrophil extracellular traps. There is now considerable evidence that much of the tissue damage in infection is due to excessive host innate immunological reaction; a hyperinflammatory response, whether localized or systemic. In addition to traditional surgical methods of drainage and decompression there is now a focus on dilution of inflammatory mediators. This emerging knowledge can potentially alter the way we approach hand infections.

We performed a detailed dynamic high-resolution ultrasound examination of the flexor tendons in trigger fingers and compared this with normal contralateral digits. There was a loss of defined linear tendon margins and/or traction of the flexor tendons on the surrounding soft tissue during passive flexion of the distal interphalangeal joint in 17 out of 20 trigger fingers, which indicated adherence to the surrounding tissues. The differential motion between the flexor digitorum profundus tendon and the flexor digitorum superficialis tendons was also lost in ten trigger fingers, which suggested adherence between the tendons. No signs of peritendinous or intertendinous adhesions were found in the healthy control fingers. We conclude that tendon adhesions are present in the majority of trigger fingers. We could not determine a relationship between the severity of triggering and the presence of adherence due to limited sample size. Level of evidence: II

We tested the tensile strength of the proximal juncture of tendon grafts with Pulvertaft tendon repairs in 18 cadaveric digital flexor tendons. These tendons were divided into three groups of six: single, two, or three weaves. Each of the interlacing weaves was secured with eight anchoring sutures. The specimens were loaded in a biomechanical tester until failure. The ultimate tensile strength did not show any significant differences across all three groups with statistical power of 0.77. The mean tendon elongation before repair failure showed significant difference at 10 mm (standard deviation (SD) 2), 16 mm (SD 3), and 15 mm (SD 3), respectively. All specimens failed by intra-tendinous pull-out of the weaves. We conclude that the two-weave Pulvertaft construct demonstrated comparable tensile strength to three weaves and tendon elongation was similar when two or three weaves were used.

This study investigated the contribution of different forearm muscles, namely the flexor carpi ulnaris, extensor carpi radialis longus and brevis, extensor carpi ulnaris and flexor carpi radialis, during the dart thrower’s motion. Thirteen healthy participants were recruited. The forearm muscle activation patterns during the dart thrower’s motion were measured using surface electromyography. The average root mean square for the extensor carpi ulnaris was found to be the highest during the dart thrower’s motion. Muscle activations during the dart thrower’s motion were heterogeneous among the participants. The results suggest the rehabilitation protocol for patients with wrist injuries should be reconsidered.

Septic arthritis of the small joints of the hand usually occurs secondary to bacterial inoculation through penetrating injury to the joint, or direct spread of infection from paronychia, felon, or pyogenic flexor tenosynovitis. Surgical treatment involves drainage and irrigation and may involve debridement if there is an open wound. We describe a method of continuous irrigation of septic joints of the hand postoperatively in the ward setting using an intravenous cannula placed within the joint and connected to an intravenous giving set with delivery of physiological fluid using a pump driver. Modifications of the technique are described for distal interphalangeal, proximal interphalangeal, and metacarpophalangeal joints and illustrated in each joint by 3 case studies. In addition to the irrigation, intravenous antibiotics were administered. All patients healed well with a full return of joint motion, no radiologic change, and a mean QuickDASH score of 4.8 at a mean follow-up duration of 3.6 months. This is a safe and simple technique that can be performed in patients with suspected or confirmed septic arthritis and carries minimal morbidity.

Background: When closed ruptures of flexor tendons of fingers occur, there is often an identifiable pathology, which should be addressed in the same surgical setting as the tendon repair. The concept of “spontaneous” tendon rupture, occurring in the absence of identified pathology, however, has also been reported in a significant number of papers. This controversy has prompted us to do a review of the existing literature.Methods: We did a review of cases of closed ruptures of the flexor digitorum profundus (FDP) of the little finger in existing literature. Fifty-three publications were retrieved by searching “FDP tendon rupture” and “little finger” using PubMed database. We analyzed data such as the zone of rupture noted intra-operatively; and any precipitating factors, pathology or trauma. We also conducted a review on papers which discussed the concept of “spontaneous rupture”.Results: Fifty-three publications were retrieved. There were 8 cases of ruptures in Zone I; 2 in Zone II; 30 in Zone III; 59 in Zone IV and 5 in Zone V. Majority of cases were associated with an element of trauma of varying severity, or pathology. A precipitating cause was not documented in 12 cases. Amongst all 36 cases of ruptures labelled as “spontaneous”, only 1 case was truly “spontaneous” without any associated trauma or pathology.Conclusions: Most reports labeled as spontaneous rupture occurred in Zone III, where tendon ruptures are rare. There are documented pathological causes or evidence of trauma to most of these cases. We conclude these ruptures may have been mislabeled as spontaneous ruptures. Bearing in mind the propensity for tendon excursion, we suspect the lack of documentation of exploration in proximal zones contributed to this mislabeling. Understanding this concept of non-spontaneity to most tendon ruptures and the common sites of rupture or pathology is crucial for a surgeon to make strategic incisions and minimize future recurrence.

To define the role of the flexor tendons in trigger finger, a high-resolution ultrasound examination was performed in 20 trigger fingers and 20 normal contralateral digits in three digital postures: full extension, mid-flexion and near-full flexion. Precise measurements of diameter and cross-sectional area of the combined tendon mass were recorded at five clearly defined locations: summit of the metacarpal head, proximal lip of the proximal phalanx (PP) and at 1/8, 1/4 and 1/2 length of the PP. In the normal tendons, there was an anatomical thickening, not previously appreciated at 1/4 length PP, in the region of the FDS bifurcation. This anatomical region moved proximally on finger flexion to the A1 pulley. In trigger fingers, the flexor tendons had greater diameter (sagittal view) and cross-sectional area than the normal side at all locations (p 0.01, p 0.001), with an even greater increase in diameter in the FDS bifurcation area (p 0.001). Trigger fingers also had thicker A1 pulleys (p 0.001). Triggering occurs on flexing the finger when the enlarged combined flexor tendon mass at the specific anatomical region of the FDS bifurcation impacts on the thickened A1 pulley, resisting its excursion.

Driven by the clinical need for a strong tissue adhesive with elastomeric material properties, a departure from legacy crosslinking chemistries was sought as a multipurpose platform for tissue mending. A fresh approach to bonding wet substrates has yielded a synthetic biomaterial that overcomes the drawbacks of free-radical and nature-inspired bioadhesives. A food-grade liquid polycaprolactone grafted with carbene precursors yields CaproGlu. The first-of-its-kind low-viscosity prepolymer is VOC-free and requires no photoinitiators. Grafted diazirine end-groups form carbene diradicals upon low energy UVA (365 nm) activation that immediately crosslink tissue surfaces; no pre-heating or animal-derived components are required. The hydrophobic polymeric environment enables metastable functional groups not possible in formulations requiring solvents or water. Activated diazirine within CaproGlu is uniquely capable of crosslinking all amino acids, even on wet tissue substrates. CaproGlu undergoes rapid liquid-to-biorubber transition within seconds of UVA exposure–features not found in any other bioadhesive. The exceptional shelf stability of CaproGlu allows gamma sterilization with no change in material properties. CaproGlu wet adhesiveness is challenged against current unmet clinical needs: anastomosis of spliced blood vessels, anesthetic muscle patches, and human platelet-mediating coatings. The versatility of CaproGlu enables both organic and inorganic composites for future bioadhesive platforms. Agency for Science, Technology and Research (A*STAR) Ministry of Education (MOE) Published version NTU-Surgery ACP, Strategic Joint Research Fund (SJRF): Fast, 2 min surgical procedure for splicing of blood vessels; Singapore General Hospital Research Grant (SRGOF16Jan29): Dynamic release of local anaesthetics through novel tissue adhesives; Ministry of Education Tier 1 Grant: Coil Expanding Layers (COELS) For Intravascular Repairs; Ministry of Education Tier 2 Grant: Tailored soft-tissue bioadhesives for site-specific therapy (MOE2012-T2-2-046) & CaproGlu, Double sided wet-tissue adhesives (MOE2018-T2-2-114); NTU-Northwestern Institute for Nanomedicine Grant: 3D-Printing of Electro-Curing Nanocomposite Living Electrodes for Cardiac Tissue Regeneration; NTUitive POC (Gap) Fund Aesthetic Applications of CaproGlu Bioadhesives NGF/2018/05/; A*Star IAF PP Grant (H19/01/a0/0II9): CathoGlu Bioadhesivespreventing catheter extravasation and skin infections. JVH acknowledges support for the solid state NMR instrumentation at Warwick used in this research which was funded by EPSRC (grants EP/M028186/1 and EP/K024418/1) the University of Warwick, and the Birmingham Science City AM1 and AM2 projects which were supported by Advantage West Midlands (AWM) and the European Regional Development Fund (ERDF).

Multiple imaging modalities have been used to investigate normal wrist mechanics or detect wrist instabilities. While synovial fluid aspiration and biochemical analysis have also been used to study synovial fluid properties in normal and diseased wrist joints, this study aims to measure dynamic changes in intra-articular synovial fluid pressure of the scapholunate joint during repetitive radioulnar deviation. Cadaveric wrist specimens were mounted onto a custom-made motion simulator and moved at 0.5 Hz, from 20° ulnar deviation to 10° radial deviation and back. With guidance of a mini C-arm, a 25-gauge needle was inserted into the scapholunate joint and 0.5 mL of commercially available synovial fluid was injected into the joint. An external pressure transducer was connected to the needle and five sets of intra-articular synovial fluid pressure data were recorded over a period of 8 s. Periodical changes in intra-articular synovial fluid pressure were observed. The mean synovial fluid pressure changes of 4 specimens were 50.7 ± 9.0 Pa, 8.6 ± 3.7 Pa, 49.2 ± 8.8 Pa and 10.1 ± 2.2 Pa. We believe that the periodical changes in intra-articular synovial fluid pressure could be due to the net flow of synovial fluid and hysteresis effect of the scaphoid and lunate movements during radioulnar deviation.

Background The acceptable incidence of thrombophlebitis following intravenous cannulation is 5%, as recommended by the Intravenous Nurses Society guidelines, but publications have reported startling figures of 20% to 80%. Given the frequency of intravenous lines, this presents a potential clinical problem. We aimed to determine the predisposing patient, catheter, and health care-related factors of peripheral vein thrombophlebitis in the upper extremity. Methods In this systematic review, we used a comprehensive search strategy to identify risk factors of thrombophlebitis from inception to May 20, 2019. Studies reporting risk factors of peripheral vein thrombophlebitis of adult patients admitted to the hospital and receiving an intravenous cannulation were included. The Quality of Prognostic Studies tool was used in the assessment for risk of bias to determine the study quality. Results Of the 6910 studies initially identified, 25 were eligible for inclusion. Qualitative syntheses revealed that patient-related factors that confer a higher risk included intercurrent illness, immunocompromised state, comorbidities such as diabetes mellitus, malignancy, previous thrombophlebitis, burns, and higher hemoglobin levels. Catheter-related risk factors included catheter size, duration, and site of insertion. Intravenous antibiotics and potassium chloride predisposed to thrombophlebitis. Cannulation by an intravenous therapy team and more nursing care were associated with a decreased risk. A P-value Conclusion Recognition of the predisposing factors would allow for targeted strategies to aid in the prevention of this iatrogenic infection, which may include closer monitoring of patients who are identified to be vulnerable. Based on this systematic review, we developed an algorithm to guide clinical management. Further research is warranted to validate this algorithm.

We assessed the efficacy of ketorolac trometamol injections compared with triamcinolone acetonide injections in trigger digits. Patients with trigger digits were randomized to receive either ketorolac or triamcinolone. They were followed up at 3, 6, 12 and 24 weeks, and monitored for resolution of triggering, pain and total active motion. One hundred and twenty-one patients with single trigger digits were recruited (59 ketorolac, 62 triamcinolone). At 6 weeks, 54% of patients in the triamcinolone group had complete resolution of trigger, whereas no patients in the ketorolac group had resolution. At 12 weeks, 58% of patients in the triamcinolone group had complete resolution of trigger compared with 6.7% in the ketorolac group. At 24 weeks, both groups had comparable rates of resolution at 26% and 25%, respectively. Patients in the triamcinolone group had significantly better resolution of pain at 3, 6 and 12 weeks. But at 24 weeks, there was no significant difference in pain between both groups. Significantly less flexion deformity was reported at 3 weeks and 6 weeks in the triamcinolone group. In the short term, ketorolac was less effective in relieving symptoms of trigger digit than triamcinolone. Level of evidence: I

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Background: Synthetic sutures such as Fiberwire used in flexor tendon repairs have high tensile strength. Proper application allows early mobilisation, decreasing morbidity from repair rupture and adhesions while preserving range of motion. Suture stiffness can cause poorer knot holding, contributing to gapping, peritendinous adhesions or rupture. Previous studies recommended more throws in knots tied on Fiberwire to prevent knot slippage. These larger knots are voluminous and prominent. In tendon repairs they can cause “catching”, increase friction and work of flexion. Other studies advocated certain complicated knots as being more secure. We evaluated several knots and their biomechanical properties with the aim of finding a compact knot with less potential for slippage to maximise strength potential of flexor tendon repairs using Fiberwire. Methods: A series of different knots tied on Fiberwire 4-0 sutures were pulled to failure on a mechanical tester. Mean tensile strengths, knot volumes and tensile strength to knot volume ratios were compared. Results: Tensile strengths and knot volume increased with more throws and loops. Four variations of the square knot (the 4=4=1, 2=2=2=2, 1=1=1=1=1, 2=1=1=1=1 knots) had tensile strengths greater than 35N. The specialised anti-slip knot had highest tensile strength and suture volume but lower strength-to-volume ratio. Conclusions: The anti-slip knot had highest tensile strength but it also had the highest volume. The greater strength of repair may not translate into improved clinical outcome. The 1=1=1=1=1 knot has superior knot strength-to-volume ratio with good knot strength adequate for early active mobilisation in flexor tendon repairs.

Dear Sir,The importance of evidence-based medicine has been emphasized for many years. Levels of evidence range from I to V, where level I studies are most rigorously designed and represent the ‘best evidence’. Randomized controlled trials (RCTs) are recognized as the ‘gold standard’ for evaluating interventions. However, there is a paucity of high level evidence in surgical literature. The quality of hand surgery publications has not been fully reported. Our study evaluated levels of evidence and quality of RCTs in hand and wrist surgery publica-tions in

The anatomy and function of Cleland's ligaments— thought by the authors to require clarification because of the conflicting anatomic descriptions in the literature— are reviewed. A statistical representation of the structure of these ligamentous bundles was derived from the study of 16 fixed human cadaveric digits and five fresh cadaveric digits, all from different patients. The results demonstrate a large variation in anatomy. However, this anatomic heterogeneity is not indicative of an equally varied function. In general, it was found that the majority of Cleland's ligaments traversed a great distance adherent to the skin before actually inserting in the dermis. Over one-third of the dorsal fibers demonstrated a multiplanar organization, fanning out before inserting into the skin. In contrast, the ventral fibers did not fan out before inserting into the skin. Excision of these ventral fibers revealed a separate “ledgelike” plane of fibers arising from the fibrous flexor sheath and running in a straight line perpendicular to the long axis of the digit. A branch of the digital nerve was found to pierce this ligamentous layer in the majority of digits studied. Unlike those of previous reports, the results of the present study suggest that the ligaments have a constant function of anchoring the skin of the digit on both the dorsal and ventral aspects, thereby preventing the displacement of skin during flexion of the digits. All previous studies failed to make this conclusion. The anatomic relationship to the digital neurovascular bundle also suggests that Cleland's ligaments may stabilize the digital vessels during flexion. In conclusion, Cleland's ligaments are highly functional structures and are essential for normal cutaneous stability during digital movements. (Plast. Reconstr. Surg. 109: 566, 2002.)

Electrical stimulation (ES) has been used for the treatment of wounds and has been shown to alter gene expression and protein synthesis in skin fibroblasts in vitro. Here, we have developed a new in vitro model system for testing the effects of precisely defined, different types of ES on the collagen expression of normal and keloid human skin fibroblasts. Keloid fibroblasts were studied because they show excessive collagen production. Both types of fibroblasts were electrically stimulated with alternating current (AC), direct current (DC) or degenerate waves (DW). Cells were subjected to 20, 75 and 150mV/mm electric field strengths at 10 and 60Hz frequencies. At lower electric fields, all types of ES upregulated collagen I in both cell types compared to controls. However, at higher electric field strength (150mV/mm) and frequency (60Hz), DW maximally downregulated collagen I in keloid fibroblasts, yet had significantly lower cytotoxic effects on normal fibroblasts than AC and DC. Compared to unstimulated cells, both normal skin and keloid fibroblasts showed a significant decrease in collagen I expression after 12h of DW and AC stimulation. In contrast, increasing amplitude of DC upregulated collagen I and PAI-1 gene transcription in normal and keloid fibroblasts, along with increased cytotoxicity effects. Thus, our new preclinical assay system shows highly differential effects of specific types of ES on human fibroblast collagen expression and cytotoxicity and identifies DW of electrical current (DW) as a promising, novel therapeutic strategy for suppressing excessive collagen I formation in keloid disease.

BACKGROUND: Two theories exist regarding the revascularization of skin autografts: direct anastomosis between graft vessels and bed vessels, and ingrowth of bed vessels (angiogenesis) into the graft. This study characterizes revascularization, spatially and chronologically, in a murine skin autograft model using a double-labeling technique. METHODS: Full-thickness (1 cm2) skin grafts were performed on adult male C57/Bl6 mice. After 48 hours, 60 hours, 3 days, 5 days, and 14 days (n = 3 mice per time point) terminal intracardiac perfusion with a fluorescein/dextran dye demonstrated vascular filling of graft blood vessels. Fluorescence immunohistochemistry of CD31+ endothelial cells allowed counting of total vessels and fluorescein perfusion quantification of patent vessels in the lateral graft area, central graft area, graft bed, and wound margins. RESULTS: Initial filling of graft vessels was seen after 48 hours. This included vessels in the papillary dermis of the graft, and there was no significant difference in the percentage of filled vessels in the deep dermis of the graft compared with the papillary dermis of the graft. A rapid increase in vessel filling was seen between 48 and 60 hours in all areas of the graft. Vessel filling occurred mainly in the central area of the graft rather than in the lateral areas. CONCLUSIONS: The short time course of vessel filling indicates that the initial onset of revascularization is attributable to early anastomoses between graft and bed vessels, mainly in the central area of the graft. These findings have implications for both autograft revascularization in a clinical setting and in the development of tissue-engineered skin substitutes.

The assessment of locally produced proangiogenic cytokines may be an indicator of the stromal response of an individual to wounding or cancer. This study describes the profile of VEGF production in human surgical wounds in both breast cancer patients and reduction mammoplasty controls, and assesses the changes in systemic VEGF levels and platelet profiles perioperatively.Perioperative surgical wound fluid samples and blood were collected daily up to 13 days from 52 patients undergoing breast cancer surgery (local tumor burden), delayed breast reconstruction (previous tumor burden but none present at the time of surgery), or breast reduction surgery (noncancer control). Samples were analyzed for VEGF by ELISA RESULTS: VEGF levels in surgical wound fluid were lowest on day 1 followed by an early peak on day 2 of900% the corresponding serum value. There was a trend in the VEGF response at the day-2 time point: reductionreconstructioncancer subgroups, with a significant difference between the reduction and cancer subgroups (P0.05). There was a 20-30-fold variation in the response between days 1 and 2, and within subgroups.Much higher local concentrations of angiogenic factors may need to be antagonized for effective antiangiogenic therapy, and there is great heterogeneity between patients. The small peripheral blood changes compared with large tumor fluid changes show that there is a tissue barrier. This has relevance for design of antiangiogenic therapy trials, highlighting the need for individually tailored treatment with biologically targeted interventions.