A multivariate analysis on characteristics of hand and wrist tumours: a multiethnic study.

INTRODUCTION: Hand tumours are frequently encountered in clinical practice. However, large-scale epidemiological data of soft tissue tumours in the hand are infrequently published. Epidemiological data provide diagnostic cues to guide the workup and management of hand tumours. Assessing significant independent demographic factors and tumour characteristics associated with hand tumours is essential in health care. METHODS: A retrospective review of patients who underwent excision of hand tumours in Singapore General Hospital between 2004 and 2015 was conducted. The data collected included age, gender, ethnicity, histological diagnosis, malignancy and location of tumour. Generalised linear latent and mixed models (GLLAMM) analyses were performed. RESULTS: A total of 4476 tumours were identified from 4226 patients with a mean age of 51.3 (range 8-101) years and male to female ratio of 1 to 1.15. Most patients were Chinese (75%), followed by Malay (9%), Indian (8%) and others (8%). The most common hand tumours excised were ganglions (43%) (majority in the wrist), followed by giant cell tumours (9%) (commonly in the digits). Most soft tissue tumours were benign (97%), with only 3% of malignant cases. The GLLAMM analyses revealed further potential factors on the status of malignancy, tumour origin and tumour location. CONCLUSION: Most soft tissue tumours in the hand and wrist are benign. This can guide workup and counselling of patients before the operation. While malignant tumours are uncommon, they have the potential for significant morbidity and mortality if not appropriately evaluated or treated. The application of GLLAMM analyses showed that age, ethnicity and gender were significant predictors of malignancy.

Investigating the biomechanical behaviour of tendon-loaded wrist joint using web-like kinematic network model.

The complexity of wrist anatomy and mechanics makes it challenging to develop standardized measurements and establish a normative reference database of wrist biomechanics despite being studied extensively. Moreover, heterogeneity factors in both demographic characteristics (e.g. gender) and physiological properties (e.g. ligament laxity) could lead to differences in biomechanical behaviour even within healthy groups. We investigated the kinematic behaviour of the carpal bones by creating a virtual web-like network between the bones using electromagnetic (EM) sensors. Our objective was to quantify the changes in the carpal bones' biomechanical relative motions and orientations during active wrist motion in the form of orb-web architecture. Models from five cadaveric specimens at different wrist positions: (1) Neutral to 30° Extension, (2) Neutral to 50° Flexion, (3) Neutral to 10° Radial Deviation, (4) Neutral to 20° Ulnar Deviation, and (5) Dart-Throw Motion - Extension (30° Extension/10° RD) to Dart-Throw Motion Flexion (50° Flexion/20° UD), in both neutral and pronated forearm have been analyzed. Quantification analyses were done by measuring the changes in the network thread length, as well as determining the correlation between the threads at different wrist positions. We observed similarities in the kinematic web-network patterns across all specimens, and the interactions between the network threads were aligned to the carpal bones' kinematic behaviour. Furthermore, analyzing the relative changes in the wrist web network has the potential to address the heterogeneity challenges and further facilitate the development of a 3D wrist biomechanics quantitative tool.

Secondary Intention Healing for Fingertip Amputations in a Tropical Climate.

Background: Various studies have examined occlusive dressings in fingertip amputations and reported good outcomes. Occlusive dressing preserves appropriate pH, cell accumulation and moisture for healing, thereby limiting scar formation and deformity. To our knowledge, no study was performed in tropical Asia. This study aims to demonstrate the viability of healing fingertip amputations through secondary intention using an effective dressing technique, even in warm tropical climates. Methods: All patients who presented to our institution with fingertip amputations from 1 July 2020 to 31 July 2022 were analysed retrospectively. Seventeen patients (15 male, 2 female) of mean age 37.2 ± 9.4 years old with 18 injured digits were retrospectively analysed. Twelve (66.7%) were Allen Type III injuries, and one patient required distal phalangeal K-wire fixation. During the patient's final review, static 2-point discrimination, pulp sensation, fingertip contour and nail deformities alongside the last measured range of motion (ROM) of the injured finger was recorded. Treatment duration and days of leave taken were also summed and assessed. Results: Patients were dressed with semi-occlusive dressing for an average of 20.1 ± 6.83 days. The average total duration of dressing is 36.78 ± 18.88 days over an average of 7.18 ± 4.03 dressing visits. Mean duration of follow-up was 108 ± 63.46 days. Good outcome measures in sensation, pulp contour, nail deformity and ROM similar to existing literature were reported. Conclusions: Occlusive dressing remains a viable and feasible treatment option for fingertip amputation even in a tropical climate. While this simple treatment method may require more effort from patient, wound healing was attained after 36.8 ± 18.9 days of dressing. Level of Evidence: Level IV (Therapeutic).

Techniques for Continuous Catheter Irrigation of a Septic Metacarpophalangeal Joint.

Septic arthritis of the metacarpophalangeal joint (MCPJ) compromises 9% of hand infections in Singapore. Common surgical treatment is open arthrotomy and joint washout. The wound is often left open for drainage postoperatively. Repeated debridement and secondary closure are frequently needed after the index surgery. We describe a method of continuous catheter irrigation of septic MCPJ joint using an infant feeding catheter. This method provides great infection clearance to avoid repeated debridement and allows primary closure of the wound to avoid secondary closure. This method also significantly reduces postoperative pain so that to facilitate early mobilization of the joint, which is crucial for functional recovery. We illustrate the techniques of this procedure and key points of postoperative management in the ward with case examples to demonstrate its simplicity, safety, and efficacy in treating MCPJ septic arthritis.

First dorsal interosseous muscle reconstruction: a systematic review of its attachments.

PURPOSE: The first dorsal interosseous (FDI) muscle, when impaired due to traumatic injuries or degenerative conditions, can be reanimated in various ways to restore pinch grip. These reconstructive techniques are planned based on a precise anatomical understanding of the FDI muscle. However, a review of the existing literature has brought to light controversy regarding its insertions. A systematic review of these descriptions is presented to appreciate these variations. METHODS: An electronic database search without exclusion by publication year and language was performed according to the Checklist for Anatomical Reviews and Meta-Analyses (CARMA) guidelines, using the PubMed, Scopus, Web of Science and Embase databases. An assessment of the methodological quality was performed. RESULTS: Thirteen studies were included in this article. There is general agreement that the FDI muscle contains two bellies and a bony insertion into the index finger proximal phalanx base. However, due to wide anatomic variation, differences were reported on whether there is a soft tissue insertion. When this was found, the included studies differed on how commonly this occurs (between 1.4% and 78%), where it inserts. Other sites of distal insertions reported include the metacarpophalangeal capsule, the interosseous hood and an assemblage nucleus on the volar plate. CONCLUSIONS: Our systematic review, focusing on the insertion of the FDI muscle, summarizes the existing knowledge on its anatomy and variations, thereby facilitating better understanding of its function and surgical planning for reconstruction.

Comparing the torsional resistance of different fixation techniques for spiral metacarpal fractures.

This study aimed to compare the torsional resistance of three fixation techniques for spiral metacarpal fractures: screw-only fixation, screw plus neutralization plate fixation, and a locking plate construct. A spiral fracture was created on 18 cadaveric metacarpal bones by applying an axial and torsional loading force using an Instron 3343 mechanical tester. The failure strength was defined as the native torque strength. The fractures were divided into three groups and fixed using each of the three techniques. The repaired bones were loaded to failure to determine the post-repair strength. The neutralization plate group conferred a post-repair torque (278.6 Nmm) that was similar to the native torque (292 Nmm) with a diminution of only 4.5% and appeared to provide the best resistance to torsion.

Hand infection: a management approach based on a new understanding of combined bacterial and neutrophil mediated tissue damage.

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.

Understanding the biomechanics of the forearm during the dart thrower's motion.

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.

Biomechanics of surgical knot security: a systematic review.

BACKGROUND: This review aims to identify publications on quantitative biomechanical testing of surgical knot security and the physical factors that determine knot security and failure. MATERIALS AND METHODS: An electronic literature search was performed in accordance with PRISMA guidelines in January 2022 utilizing the PubMed and Google Scholar databases to look for objective biomechanical studies on knot security in surgery using the primary terms 'knot security' and 'biomechanical testing'. RESULTS: Thirty-six articles were included. Twenty-four configurations of surface, laparoscopic, and arthroscopic knots were studied. Biomechanical tensile testing was used to evaluate knot security in vitro . Load to failure (N) and elongation at knot failure (mm) were quantified by static and cyclic testing to evaluate the knot holding capacity and failure mechanism of slippage or rupture. CONCLUSION: This review reassures that the knot configuration, suture materials, suture sizes, and number of throws are key factors in determining the knot's security. Knot configuration has to be simple for laparoscopic and arthroscopic knots due to the confined space of the operating site. With the advent of stronger suture materials for high-tension surgical reconstructive procedures, there is an unmet need to understand the physical behavior of the knot and the factors that determine its resistance to slippage or rupture.Level of Evidence: Level IV.

Surgical Management of Peripheral Vein Thrombophlebitis in the Upper Extremity.

Purpose: Peripheral vein thrombophlebitis has a reported overall incidence ranging from 20% to 80%. Thrombophlebitis can progress despite antibiotic therapy to become a challenging clinical problem requiring surgical intervention. There is currently no consensus on its optimal management. We reviewed our experience of surgical intervention with analyses of the indications for intervention, descriptions of the surgical procedures, and outcomes. We aimed to provide guidance on the management of this potentially serious complication. Methods: This is a retrospective review of 51 patients with thrombophlebitis refractory to conservative management between January 2017 and August 2020. Results: Analyses revealed a high prevalence of comorbidities, including diabetes mellitus, malignancy, and chronic kidney disease. A total of 60% of patients had concurrent bacteremia, and the decision to operate had a low threshold in the presence of these factors. On exploration, 80% of patients had intraluminal thrombus, 47% had intraluminal pus, and 29% had pus beyond the veins or extending proximally. The surgical approach employed in 98% of patients involved an extensile incision in those with several morbidity factors (diabetes mellitus, chronic kidney disease, or bacteremia). One patient presented with severe clinical signs of local infection, and on exploration, there was intraluminal pus and thrombus up to 10 cm. A novel technique of a minimally invasive approach of intermittent stab incisions was employed in a young and healthy patient without comorbidities. Conclusions: We developed an algorithm to guide the indications for intervention and surgical approach to thrombophlebitis. The threshold for intervening surgically should be lowered by the presence of comorbidities. The failure of antibiotics to resolve the clinical signs of infection or the suspicion of abscess formation should mandate intervention. Thrombosed sections of the vein should be ligated proximally and distally and excised and surrounding collections of pus drained. Delayed secondary wound closure is usual. Stab incisions may limit surgical dissection and subsequent scarring in less severe cases. Type of study/level of evidence: Prognostic IV.

A fluid-structure interaction investigation of intra-articular pressure and ligament in wrist joint.

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.

Biomechanical Study of Modified Massachusetts General Hospital Flexor Tendon Repair Using Looped Sutures.

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.

Delivery of Wnt inhibitor WIF1 via engineered polymeric microspheres promotes nerve regeneration after sciatic nerve crush.

Injuries within the peripheral nervous system (PNS) lead to sensory and motor deficits, as well as neuropathic pain, which strongly impair the life quality of patients. Although most current PNS injury treatment approaches focus on using growth factors/small molecules to stimulate the regrowth of the injured nerves, these methods neglect another important factor that strongly hinders axon regeneration-the presence of axonal inhibitory molecules. Therefore, this work sought to explore the potential of pathway inhibition in promoting sciatic nerve regeneration. Additionally, the therapeutic window for using pathway inhibitors was uncovered so as to achieve the desired regeneration outcomes. Specifically, we explored the role of Wnt signaling inhibition on PNS regeneration by delivering Wnt inhibitors, sFRP2 and WIF1, after sciatic nerve transection and sciatic nerve crush injuries. Our results demonstrate that WIF1 promoted nerve regeneration (p < 0.05) after sciatic nerve crush injury. More importantly, we revealed the therapeutic window for the treatment of Wnt inhibitors, which is 1 week post sciatic nerve crush when the non-canonical receptor tyrosine kinase (Ryk) is significantly upregulated.

Catheter irrigation as an unutilized novelty in the treatment of water-based paint injection injuries - a case illustration.

High-pressure injection injuries with paint have long been heralded as a condition requiring timely and aggressive debridement with relatively poor functional outcomes and a significant proportion of patients progressing to require amputation of the involved digit or limb. Catheter irrigation is regularly used in the treatment of common hand infections and wounds. However, this has not been described for the treatment of paint injection injuries. We describe a case of a young painter who sustained an accidental water-based paint injection injury and was successfully treated with minimally invasive surgical debridement augmented by the use of catheter irrigation, despite a delayed presentation. The patient had regained full function of his hand by four months from the index presentation and returned to work. We illustrate how not all high-pressure injection injuries require an extensive incision and that catheter irrigation can be a significant tool to augment a minimally invasive approach.

Adhesions as a component of the trigger finger: a dynamic sonographic study.

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.

CaproGlu: Multifunctional tissue adhesive platform.

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.

The strengths of one-, two-, and three-weave Pulvertaft tendon repairs.

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.

Peripheral Vein Thrombophlebitis in the Upper Extremity: A Systematic Review of a Frequent and Important Problem.

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 < .5 was considered to be statistically significant. 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.