Search

Tissue engineering of flexor tendons addresses a challenge often faced by hand surgeons: the restoration of function and improvement of healing with a limited supply of donor tendons. Creating an engineered tendon construct is dependent upon understanding the normal healing mechanisms of the tendon and tendon sheath. The production of a tendon construct includes: creating a three-dimensional scaffold; seeding cells within the scaffold; encouraging cellular growth within the scaffold while maintaining a gliding surface; and finally ensuring mechanical strength. An effective construct incorporates these factors in its design, with the ultimate goal of creating tendon substitutes that are readily available to the reconstructive hand surgeon. [ABSTRACT FROM PUBLISHER]

The aim of this Delphi study was to provide a diagnostic and treatment algorithm for patients with persistent or recurrent symptoms after trapeziometacarpal joint resection arthroplasty. Three Delphi rounds were conducted in which surveys were sent to 182 experienced hand surgeons worldwide. Responses were received from 140 participants. A consensus threshold was set at 67% agreement. Diagnostic tools and treatment approaches for six common revision scenarios achieved consensus. Radiographs are appropriate as primary (97%) and CT scans as secondary (76%) diagnostic tools. For scaphometacarpal impingement, 67% of respondents agreed that revision interposition is appropriate, with 93% recommending autologous tendon for the interposition. Additional suspension was considered appropriate by 68% of the participants. The diagnostic and treatment algorithm can help the surgeon to identify the reason for persistent symptoms after trapeziometacarpal joint resection arthroplasty and to choose an appropriate treatment strategy. Level of evidence: V., Competing Interests: Declaration of conflicting interestsThe authors declare no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: The aim of this systematic literature review was to describe current indications and interventions for revisions after trapeziometacarpal joint (TMJ) resection arthroplasty., Methods: The literature search was conducted by an experienced librarian in the MEDLINE, Embase, Cochrane Library, Web of Science, and Scopus databases. The authors included all articles that investigated any TMJ arthroplasty procedure in which the trapezium was completely resected and if any subsequent revision procedure including joint-related and soft-tissue operations was mentioned. Two independent reviewers selected the articles and were involved in data extraction., Results: Sixty-two articles reporting on 5284 operated thumbs and 434 revision operations were included. Twenty-four indications for revision and 31 revision techniques were extracted. Most revisions were performed because of subsidence/impingement of the first metacarpal bone ( n = 194 thumbs) followed by unspecified pain ( n = 53), metacarpophalangeal joint problems ( n = 28), and scaphotrapezoidal osteoarthritis ( n = 17). Eleven treatment strategies were found for subsidence/impingement of the first metacarpal, the most frequent being revision of the existing interposition using autologous tendon ( n = 46) and soft-tissue interposition with distraction pinning ( n = 28)., Conclusions: There are a wide variety of indications and even more surgical techniques described in the literature to treat persisting or recurrent pain after TMJ resection arthroplasty. Currently, there is no uniform treatment guideline available on how to diagnose and treat such cases. Therefore, the results of this literature review will form the basis for a Delphi study aiming to develop recommendations for the diagnosis and treatment of persistent/recurrent pain after TMJ resection arthroplasty., (Copyright © 2024 by the American Society of Plastic Surgeons.)

Soft and stretchable nanocomposites can match the mechanical properties of neural tissue, thereby minimizing foreign body reactions to provide optimal stimulation and recording specificity. Soft materials for neural interfaces should simultaneously fulfill a wide range of requirements, including low Young's modulus (<<1 MPa), stretchability (≥30%), high conductivity (>> 1000 S cm -1 ), biocompatibility, and chronic stability (>> 1 year). Current nanocomposites do not fulfill the above requirements, in particular not the combination of softness and high conductivity. Here, this challenge is addressed by developing a scalable and robust synthesis route based on polymeric reducing agents for smooth, high-aspect ratio gold nanowires (AuNWs) of controllable dimensions with excellent biocompatibility. AuNW-silicone composites show outstanding performance with nerve-like softness (250 kPa), high conductivity (16 000 S cm -1 ), and reversible stretchability. Soft multielectrode cuffs based on the composite achieve selective functional stimulation, recordings of sensory stimuli in rat sciatic nerves, and show an accelerated lifetime stability of >3 years. The scalable synthesis method provides a chemically stable alternative to the widely used AgNWs, thereby enabling new applications within electronics, biomedical devices, and electrochemistry., (© 2024 The Author(s). Small published by Wiley‐VCH GmbH.)

Purpose: This study aimed to compare the outcome in terms of range of motion between early active flexion and extension (early active motion, [EAM]) and passive flexion using rubber bands followed by active extension (sometimes referred to as a Kleinert regimen) after flexor tendon repair in zones 1 and 2., Methods: Data were collected from the Swedish national health care registry for hand surgery (HAKIR). Rehabilitation regimens were decided by the preference of each caregiver. At 3 months, 828 digits (656 EAM and 172 passive flexion) and at 12 months, 448 digits (373 EAM and 75 passive flexion) were available for analysis. Thumbs were analyzed separately., Results: No notable difference in total active motion was found between the groups at 12 months of follow-up., Conclusions: This large registry study supports the hypothesis that EAM rehabilitation may not lead to better range of motion long-term than passive motion protocols., Type of Study/level of Evidence: Therapeutic IV., Competing Interests: Conflicts of Interest No benefits in any form have been received or will be received related directly to this article., (Copyright © 2024 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

Background: Indocyanine green fluorescence angiography (ICG-FA) is often used for assessing tissue circulation in reconstructive surgery. Indocyanine green (ICG) is injected intravenously and visualized in the tissue with an infrared camera. The information is used to plan the surgery, for example, in free flap breast reconstructions. Laser speckle contrast imaging (LSCI) is another method that uses laser to assess tissue perfusion in the skin. Unlike ICG-FA, LSCI is noninvasive and may therefore have an advantaged compared with ICG-FA. The aim of this study was to evaluate the correlation between information obtained from these two techniques., Methods: Five deep inferior epigastric perforator patients were included. The flaps were assessed with LSCI and ICG-FA. For LSCI, the perfusion was calculated in 32 regions of interest. For ICG-FA, the maximum slope and area under curve (AUC) were calculated based on average pixel intensity data., Results: Large variations in maximum slope values could be seen between flaps, whereas AUC had lower variability within the same flap and between flaps. Pearson rank correlation comparing average perfusion (LSCI) and AUC (ICG-FA) showed a correlation between the values (r = 0.55, P < 0.0001). No significant correlation was observed between perfusion and maximum slope (r = 0.11, P = 0.18)., Conclusions: There is a significant correlation between data obtained using LSCI and ICG-FA, when ICG-FA data are presented as AUC of the ICG-FA intensity curve. Maximum slope lacks significant correlation with flap data obtained with LSCI. The study indicates that LSCI may be used in reconstructive surgery to assess tissue circulation in a way similar to ICG-FA., Competing Interests: The authors have no financial interest to declare in relation to the content of this article., (Copyright © 2024 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of The American Society of Plastic Surgeons.)

Optimal recovery of muscle function after proximal nerve injuries remains a complex and challenging problem. After a nerve injury, alterations in the affected muscles lead to atrophy, and later degeneration and replacement by fat-fibrous tissues. At present, several different strategies for the preservation of skeletal muscle have been reported, including various sets of physical exercises, muscle massage, physical methods (e.g. electrical stimulation, magnetic field and laser stimulation, low-intensity pulsed ultrasound), medicines (e.g. nutrients, natural and chemical agents, anti-inflammatory and antioxidants, hormones, enzymes and enzyme inhibitors), regenerative medicine (e.g. growth factors, stem cells and microbiota) and surgical procedures (e.g. supercharge end-to-side neurotization). The present review will focus on methods that aimed to minimize the damage to muscles after denervation based on our present knowledge., Competing Interests: Declaration of conflicting interestsThe authors declare no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

The pathophysiological mechanism behind complications associated with postmastectomy radiotherapy (PMRT) and subsequent implant-based breast reconstruction are not completely understood. The aim of this study was to examine if there is a relationship between PMRT and microvascular perfusion and saturation in the skin after mastectomy and assess if there is impaired responsiveness to a topically applied vasodilator (Methyl nicotinate - MN). Skin microvascular perfusion and oxygenation >2 years after PMRT were measured using white light diffuse reflectance spectroscopy (DRS) and laser Doppler flowmetry (LDF) in the irradiated chest wall of 31 women with the contralateral breast as a control. In the non-irradiated breast, the perfusion after application of MN (median 0.84, 25th-75th centile 0.59-1.02 % RBC × mm/s) was higher compared to the irradiated chest wall (median 0.51, 25th-75th centile 0.21-0.68 % RBC × mm/s, p < 0.001). The same phenomenon was noted for saturation (median 91 %, 25th-75th centile 89-94 % compared to 89 % 25th-75th centile 77-93 %, p = 0.001). Eight of the women (26%) had a ≥10 % difference in skin oxygenation between the non-irradiated breast and the irradiated chest wall. These results indicate that late microvascular changes caused by radiotherapy of the chest wall significantly affect skin perfusion and oxygenation., Competing Interests: Declaration of competing interest Fredriksson is part-time employed by Perimed, AB, which is developing products related to research described in this publication. None of the other authors has disclosable conflicts of interests., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Purpose: Scaphoid fractures in patients and assessment of healing using PCD-CT have, as far as we know, not yet been studied. Therefore, the aim was to compare photon counting detector CT (PCD-CT) with energy integrating detector CT (EID-CT) in terms of fracture visibility and evaluation of fracture healing., Method: Eight patients with scaphoid fracture were examined with EID-CT and PCD-CT within the first week post-trauma, and with additional scans at 4, 6 and 8 weeks. Our clinical protocol for wrist examination with EID-CT was used (CTDI vol 3.1 ± 0.1 mGy, UHR kernel Ur77). For PCD-CT matched radiation dose, reconstruction kernel Br89. Quantitative analyses of noise, CNR, trabecular and cortical sharpness, and bone volume fraction were conducted. Five radiologists evaluated the images for fracture visibility, fracture gap consolidation and image quality, and rated their confidence in the diagnosis., Results: The trabecular and cortical sharpness were superior in images obtained with PCD-CT compared with EID-CT. A successive reduction in trabecular bone volume fraction during the immobilized periods was found with both systems. Despite higher noise and lower CNR with PCD-CT, radiologists rated the image quality of PCD-CT as superior. The visibility of the fracture line within 1-week post-trauma was rated higher with PCD-CT as was diagnostic confidence, but the subsequent assessments of fracture gap consolidation during healing process and the confidence in diagnosis were found equivalent between both systems., Conclusion: PCD-CT offers superior visibility of bone microstructure compared with EID-CT. The evaluation of fracture healing and confidence in diagnosis were rated equally with both systems, but the radiologists found primary fracture visibility and overall image quality superior with PCD-CT., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Postmastectomy radiotherapy (PMRT) increases the risk for complications after breast reconstruction. The pathophysiological mechanism underlying this increased risk is not completely understood. The aim of this study was to examine if there is a relationship between PMRT and microvascular perfusion in the skin directly after, and at 2 and 6 months after PMRT and to assess if there is impaired responsiveness to a topically applied vasodilator (Methyl nicotinate-MN) after PMRT. Skin microvascular responses after PMRT were measured on two sites in the irradiated chest wall of 22 women before, immediately after, and at 2 and 6 months after unilateral PMRT with the contralateral breast as a control. A significant increase in basal skin perfusion was observed in the irradiated chest wall immediately after RT (p < 0.0001). At 2 and 6 months after RT, there was no longer a difference in basal skin perfusion compared to the contralateral breast and compared to baseline. Similarly, the blood flow response in the skin after application of MN was stronger immediately after RT compared to before RT (p < 0.0001), but there was no difference at later time points. These results indicate that the increased risk for complications after surgical procedures are not directly related to changes in skin perfusion and microvascular responsiveness observed after postmastectomy RT., (© 2024. The Author(s).)

The aim of this study was to analyse the short- and medium-term complications of the Motec total wrist arthroplasty (TWA). Identifying exact modes of failure and their causes should allow surgeons to avoid or mitigate these risks in the future. Retrospective analysis of prospectively collected data from six hand surgeons at five international centres provided details of 171 Motec TWAs. The mean follow-up was 5.8 years (range 18 months to 12 years). There were 33 (19%) complications within our cohort, with a revision rate of 8.2% (14 revisions). There was no difference in complication rates between metal-on-metal and metal-on-polymer articulations. Failure of osseointegration was the most common complication. Problems with soft tissue balancing, implant impingement related osteolysis, bony impingement and metacarpal fracture were found to be other preventable causes of failure in this series. Elimination of these preventable complications will improve survival rates for this implant. Level of evidence: IV., Competing Interests: Declaration of conflicting interestsThe authors declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: DB, SF, MS and TT are consultants for Swemac Innovation AB (Linkoping, Sweden).

Background: Indocyanine green fluorescence angiography (ICG-FA) is used to assess tissue intraoperatively in reconstructive surgery. This requires an intra-venous dye injection for each assessment. This is not necessary in laser speckle contrast imaging (LSCI); therefore, this method may be better suited for tissue evaluation. To determine this, we compared the two methods in a porcine flap model., Methods: One random and one pedicled flap were raised on each buttock of six animals. They were assessed with LSCI at baseline, when raised (T 0 ), at 30 minutes (T 30 ) and with ICG-FA at T 0 and T 30 . Regions of interest (ROI) were chosen along the flap axis. Perfusion, measured as perfusion units (PU) in the LSCI assessment and pixel-intensity for the ICG-FA video uptake, was calculated in the ROI. Correlation was calculated between PU and pixel-intensity measured as time to peak (TTP) and area under curve for 60 seconds (AUC 60 )., Results: Correlation between LSCI and AUC 60 for the ICG-FA in corresponding ROI could be seen in all flaps at all time points. The correlation was higher for T 0 (r=0.7 for random flap and r=0.6 for pedicled flap) than for T 30 (r=0.57 for random flap and r=0.59 for pedicled flap). Even higher correlation could be seen PU and TTP (T 0 : random flap r=-0.8 and pedicled flap r=0.76. T 30 : random flap r=-0.8 and pedicled flap r=0.71)., Conclusion: There is a correlation between PU from LSCI and TTP and AUC 60 for ICG-FA, indicating that LSCI could be considered for intraoperative tissue assessment., Competing Interests: The authors have no financial interest to declare in relation to the content of this article. Disclosure statements are at the end of this article, following the correspondence information., (Copyright © 2023 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of The American Society of Plastic Surgeons.)

The aim of this study was to compare an early active motion (EAM) regimen to a modified Kleinert passive motion therapy in Zone 2 flexor tendon injuries with regards to range of motion (ROM), grip strength and patient-reported outcome measures (PROMs). Seventy-two patients were included. At 3 months postoperatively, we found no difference in total active motion (TAM) between the EAM and the Kleinert groups (median 195.5°, range 115°-273° versus median 191.5°, range 113°-260°), but a significantly better grip strength (median 76%, range 44%-99% versus median 54%, range 19%-101%; p  <   0.0005) in the EAM group. Disabilities of the Arm, Shoulder and Hand (DASH) score as well as patient-reported weakness, cold intolerance and problems in daily activities also favoured the EAM group. At 12 months postoperatively, there was no difference in TAM, grip strength or any of the PROMs used. We conclude that EAM leads to a quicker recovery in terms of grip strength and PROMs, but that both regimens lead to similar results at 12 months. Level of evidence: I.

The aim of this study was to examine the relationship between patient-reported outcome measures (PROMs) and the original Strickland classification after flexor tendon injuries in Zones 1 and 2. Data were collected from the Swedish national health care registry for hand surgery (HAKIR). The studied PROMs were the Quick Disabilities of Arm, Shoulder and Hand (QuickDASH) and the patient questionnaire from the HAKIR (HQ-8). Complete data of both range of motion (ROM) and PROMs were available for 215 patients at 3 months after surgery, and for 150 patients at 12 months after surgery. We found that QuickDASH values were low and similar between all groups as classified by the Strickland system at 12 months. A statistically significant difference between PROM values (for stiffness and satisfaction) was found only between the Strickland groups Fair and Good, but not between Poor and Fair or Good and Excellent. This suggests that further categorization according to the Strickland classification is less important to the patients as long as they regain 70% of their ROM. Level of evidence: III.

Objective: Cold sensitivity of the fingers is common in several conditions. It has been linked to digital vasospasm, microvascular dysfunction, and neural mechanisms. This study aimed to investigate the normal digital microvascular response to a cold stress test in healthy individuals using Laser Speckle Contrast Imaging (LSCI)., Methods: Twenty-six healthy individuals, mean age 31 (SD 9) years were included. Skin perfusion of digits II-V was measured using Laser Speckle Contrast Imaging before and after a standardized cold stress test. Changes in skin perfusion from baseline were analyzed between hands, digits, and sexes., Results: Skin perfusion was significantly (p < 0.0001) affected by cold provocation in both the cold exposed and the contralateral hands in all participants of the study. This effect was significantly different between the radial (digit II and III) and the ulnar (digit V) side of the hands (p < 0.001). There was a trend towards a larger decrease in perfusion in men (ns), and a faster recovery to baseline values in women (ns). A larger inter subject variability was seen in perfusion values in women., Conclusions: The normal microvascular response to cold provocation may involve both centrally and regionally mediated processes. When exposing one hand to a cold stress test, the contralateral hand responds with simultaneous but smaller decreases in perfusion., Competing Interests: Declaration of competing interest The authors declare that there are no conflicts of interest., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

The purpose of this review article is to provide an update on the realm of emerging technology available for the assessment of dynamic functional movement of the hand and upper limb. A critical overview of the literature and a conceptual framework for use of such technologies is proposed. The framework explores three broad purpose categories including customization of care, functional surveillance and interventions through biofeedback strategies. State-of-the-art technologies are described, from basic activity monitors to feedback-enabled robotic gloves, along with exemplar trials and clinical applications. The future of technologies innovation in hand pathology is proposed in the context of the current obstacles and opportunities for hand surgeons and therapists.

Artificial intelligence (AI) in hand surgery is an emerging and evolving field that will likely play a large role in the future care of our patients. However, there remain several challenges to makes this technology meaningful, acceptable and usable at scale. In this review article, we discuss basic concepts in AI, including challenges and key considerations, provide an update on how AI is being used in hand and wrist surgery and propose potential future applications. The aims are to equip clinicians and researchers with the basic knowledge needed to understand and explore the incorporation of AI in hand surgery within their own practice and recommends further reading to develop knowledge in this emerging field.

Introduction: Fractures of the distal ulna, excluding the styloid, are rare. The cause of injury is often a fall on an outstretched hand with an extended wrist, and in most cases there is a concomitant distal radius fracture. The aims of this retrospective study were to investigate the results of the current treatment of distal ulna fractures in adults, with or without a concomitant distal radius fracture, and if a recently presented fracture classification could predict outcome., Materials and Methods: Patients, 18 years or older, treated for a fracture of the distal third of ulna in our county, were included. Fractures of the styloid tip were excluded. The radiographs of the fractures were independently classified by two specialists in radiology according to the 2018 AO/OTA classification. Follow-up was performed 5-7 years after the injury, through the questionnaire Patient-Rated Wrist Evaluation (PRWE) and new radiographs of both wrists., Results: Ninety-six patients with 97 fractures were included and filled out the PRWE. 65 patients also had new radiographs taken. 79 patients were women and the mean age at the time of injury was 63 years (SD 14.5). The most common fracture class was the extra-articular transverse fracture, 2U3A2.3 (42%). We found that 40% of the fractures had been treated by internal fixation and only 2 fractures had not healed, one conservatively treated and one operated. The median PRWE was 15 (IQR 33.5). The PRWE score was significantly worse in the operated ulna fractures (p = 0.01) and this was also true for extra-articular transverse fractures 2U3A2.3 (p = 0.001). Initial displacement was more common in operated transverse fractures, but it could not be proven that this was the reason for the inferior result., Conclusions: Distal ulna fractures almost always unite and the result is comparable to that of isolated distal radius fractures when measured by PRWE. Based on the opinions of the radiologists and how often a consensus discussion was needed for classification, we found the updated AO classification system difficult to use, if dependent only on standard radiographic views. In the present study, transverse extra-articular ulna fractures did not benefit from internal fixation regardless if associated with a distal radius fracture or isolated., (© 2022. The Author(s).)

The aim of this study was to identify risk factors for reoperations after Zones 1 and 2 flexor tendon repairs. A multiple logistic regression model was used to identify risk factors from data collected via the Swedish national health care registry for hand surgery (HAKIR). The studied potential risk factors were age and gender, socio-economics and surgical techniques. Included were 1372 patients with injuries to 1585 fingers and follow-up of at least 12 months (median 37 IQR 27-56). Tendon ruptures occurred in 80 fingers and tenolysis was required in 76 fingers. Variables that affected the risk of rupture were age >25 years ( p  < 0.001), flexor pollicis longus tendon injuries ( p  < 0.001) and being male ( p  = 0.004). Injury to both finger flexors had an effect on both rupture ( p  = 0.005) and tenolysis ( p  < 0.001). Understanding the risk factors may provide important guidance both to surgeons and therapists when treating patients with flexor tendon injuries. Level of evidence: III.

Purpose: The aim of this study was to evaluate the effect of reconstruction parameters on image quality in wrist imaging using photon-counting detector CT (PCD-CT) and to compare the results with images from an energy-integrating detector CT (EID-CT)., Methods: Twelve cadaveric wrist specimens were examined using a prototype PCD-CT and a clinical EID-CT using similar radiation dose. Reconstruction parameters were matched between scanners. Also, sharper reconstruction kernels, a larger matrix size, and smaller slice thicknesses were evaluated for PCD-CT. Image noise, contrast-to-noise ratio (CNR) and image sharpness in trabecular structures were quantitatively measured. Image quality with respect to the visibility of cortical and trabecular bone structures was assessed by six radiologists using visual grading methods., Results: Images obtained with PCD-CT had lower noise (42.6 ± 3.9 HU vs 75.1 ± 6.3 HU), higher CNR (38.9 ± 4.5 vs 19.0 ± 2.4) and higher trabecular sharpness (63.5 ± 6.0 vs 53.7 ± 8.5) than those obtained with EID-CT using similar scan and reconstruction parameters (p < 0.001). The image sharpness in trabecular structures was further improved by using sharper kernels, despite higher noise levels. Radiologists had a strong preference for PCD-CT images both in terms of spatial resolution and suitability for bone imaging. Visual grading analysis showed an improved visibility of cortical bone, trabeculae and nutritive canals (p < 0.005)., Conclusion: PCD-CT offers improved image quality regarding bone structures in the wrist relative to EID-CT systems, particularly when sharper reconstruction kernels, smaller slice thickness and a larger image matrix size are used., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

Background and Purpose: Classification of fractures can be valuable for research purposes but also in clinical work. Especially with  are fractures, such as distal ulna fractures, a treatment algorithm based on a classification can be helpful. We compared 3 different  classification systems of distal ulna fractures and investigated their reliability and reproducibility., Patients and Methods: patients with 97 fractures of the distal ulna, excluding the ulnar styloid, were included. All fractures were  independently classified by 3 observers according to the classification by Biyani, AO/OTA 2007, and AO/OTA 2018. The classification process was repeated after a minimum of 3 weeks. We used Kappa value analysis to determine inter- and intra-rater agreement., Results: The inter-rater agreement of the AO/OTA 2007 classification was judged as fair, ĸ 0.40, whereas the agreement of AO/OTA 2018 and Biyani was moderate at ĸ 0.42 and 0.43 respectively. The intra-rater agreement was judged as moderate for all classifications., Interpretation: The differences between the classifications were small and the overall impression was that neither of them was good enough to be of substantial clinical value. The Biyani classification, being developed specifically for distal ulna fractures, was the easiest and most fitting for the fracture patterns seen in our material, but lacking options for fractures of the distal diaphysis. Standard radiographs were considered insufficient for an accurate classification. A better radiographic method combined with a revised classification might improve accuracy, reliability, and reproducibility.

The field of hand surgery is constantly evolving to meet challenges of populations with increasing age and higher demands for active living. While our surgical care has improved over the last decades, it seems that future major improvement in outcomes of clinical treatment will come through advances in biologics and the translation of major discoveries in basic science. This article aims to provide an update on where basic science solutions may answer some of the most critical issues in hand surgery, with a focus on augmentation of tissue repair.

We developed a smartphone application to measure wrist motion using the mobile device's built-in motion sensors or connecting it via Bluetooth to a wearable sensor. Measurement of wrist motion with this method was assessed in 33 participants on two occasions and compared with those obtained with a standard goniometer. The test-retest reproducibility in healthy individuals ranged from good to excellent (intraclass correlation (ICC) 0.76-0.95) for all motions, both with and without the wearable sensor. These results improved to excellent (ICC 0.90-0.96) on the second test day, suggesting a learning effect. The day-to-day reproducibility was overall better with the wearable sensor (mean ICC 0.87) compared with the application without using sensor or goniometer (mean ICC 0.82 and 0.60, respectively). This study suggests that smartphone-based measurements of wrist range of motion are feasible and highly accurate, making it a powerful tool for outcome studies after wrist surgery.

Insulin has metabolic and vascular effects in the human body. What mechanisms that orchestrate the effects in the microcirculation, and how the responds differ in different tissues, is however not fully understood. It is therefore of interest to search for markers in microdialysate that may be related to the microcirculation. This study aims to identify proteins related to microvascular changes in different tissue compartments after glucose provocation using in vivo microdialysis. Microdialysis was conducted in three different tissue compartments (intracutaneous, subcutaneous and intravenous) from healthy subjects. Microdialysate was collected during three time periods; recovery after catheter insertion, baseline and glucose provocation, and analyzed using proteomics. Altogether, 126 proteins were detected. Multivariate data analysis showed that the differences in protein expression levels during the three time periods, including comparison before and after glucose provocation, were most pronounced in the intracutaneous and subcutaneous compartments. Four proteins with vascular effects were identified (angiotensinogen, kininogen-1, alpha-2-HS-glycoprotein and hemoglobin subunit beta), all upregulated after glucose provocation compared to baseline in all three compartments. Glucose provocation is known to cause insulin-induced vasodilation through the nitric oxide pathway, and this study indicates that this is facilitated through the interactions of the RAS (angiotensinogen) and kallikrein-kinin (kininogen-1) systems., (© 2021. The Author(s).)

Objective . Electrical stimulation of the peripheral nervous system (PNS) can treat various diseases and disorders, including the healing process after nerve injury. A major challenge when designing electrodes for PNS stimulation is the mechanical mismatch between the nerve and the device, which can lead to non-conformal contact, tissue damage and inefficient stimulation due to current leakage. Soft and stretchable cuff electrodes promise to tackle these challenges but often have limited performance and rely on unconventional materials. The aim of this study is to develop a high performance soft and stretchable cuff electrode based on inert materials for low-voltage nerve stimulation. Approach . We developed 50 µ m thick stretchable cuff electrodes based on silicone rubber, gold nanowire conductors and platinum coated nanowire electrodes. The electrode performance was characterized under strain cycling to assess the durability of the electrodes. The stimulation capability of the cuff electrodes was evaluated in an in vivo sciatic nerve rat model by measuring the electromyography response to various stimulation pulses. Main results . The stretchable cuff electrodes showed excellent stability for 50% strain cycling and one million stimulation pulses. Saturated homogeneous stimulation of the sciatic nerve was achieved at only 200 mV due to the excellent conformability of the electrodes, the low conductor resistance (0.3 Ohm sq -1 ), and the low electrode impedance. Significance . The developed stretchable cuff electrode combines favourable mechanical properties and good electrode performance with inert and stable materials, making it ideal for low power supply applications within bioelectronic medicine., (Creative Commons Attribution license.)

Background: Existing techniques for assessment of microcirculation are limited by their large size and high costs and are often not so easy to use. Advances in mobile technology have enabled great improvements in smartphone sensor technology. In this study, we used SkinSight, an app for iPhone and iPad, to measure changes in skin microcirculation during physiological provocations. The system estimates changes in the concentration of hemoglobin in the skin by analyzing the reflected light emitted from the built-in light-emitting diode and detected by the camera of the smartphone., Methods: A relative hemoglobin (Hb) index was measured during a 5-min arterial occlusion, post-occlusive reactive hyperemia, and a 5-min venous occlusion in 10 healthy subjects, on two separate days. The index was calculated in an area of the skin from the color information in the images acquired by the phone camera. Polarized light spectroscopy imaging was used to measure changes in red blood cell concentration for comparison., Results: During arterial occlusion, relative Hb index was unchanged compared to baseline (P = .40). After release of the cuff, a sudden 60%-75% increase in Hb index was observed (P < .001) followed by a gradual return to baseline. During venous occlusion, Hb index increased by 80% (P < .001) followed by a gradual decrease to baseline after reperfusion. Day-to-day reproducibility of the relative Hb index was excellent (ICC: 0.92, r = 0.94), although relative Hb index was consistently higher during the second day, possibly as a result of changed lighting conditions or calibration issues., Conclusion: Microvascular responses to physiological provocations in the skin can be accurately and reproducibly measured using a smartphone application. Although the system offers a handheld, easy to use and flexible technique for skin microvascular assessment, the effects of lighting on the measured values and need for calibration need to be further investigated., (© 2020 The Authors. Skin Research and Technology published by John Wiley & Sons Ltd.)

Sampling the concentration of insulin in human skin using microdialysis is challenging because of low intracutaneous concentrations and low recovery, presumably due to adsorption of insulin to the microdialysis system. In this study, we aimed to (1) measure how the concentration of insulin varies in three different tissue compartments (intracutaneous, subcutaneous and intravenous) and (2) to study how much insulin is adsorbed to the microdialysis catheter membranes and tubing during a typical microdialysis experiment, both in vivo and in vitro. We hypothesized that (1) the concentration of insulin decreases from the intravenous compartment to the intracutaneous and subcutaneous tissue, and that (2) adsorption of insulin to the microdialysis membrane and tubing impairs the recovery of insulin from the tissue. In this experimental study, microdialysis catheters were inserted intracutaneously, subcutaneously and intravenously in 11 healthy subjects. Systemic endogenous hyperinsulinemia was induced by intake of an oral glucose load. Insulin concentration was measured in the dialysate and in the extracted samples from the catheter membrane and tubings. In vitro microdialysis was performed to investigate the temporal resolution of the adsorption. After an oral glucose load insulin concentration increased intravenously, but not in the intracutaneous or subcutaneous compartments, while glucose, lactate and pyruvate concentrations increased in all compartments. The adsorption of insulin to the microdialysis membrane in vivo was highest in the intravenous compartment (p = 0.01), compared to the intracutaneous and subcutaneous compartments. In vitro, the adsorption to the microdialysis membrane was highest one hour after sampling, then the concentration gradually decreased after three and five hours of sampling. The concentration of insulin in peripheral tissues is low, probably due to decreasing tissue vascularity. Adsorption of insulin to the microdialysis membrane is modest but time-dependent. This finding highlights the importance of a stabilization time for the microdialysis system before sampling tissue analytes.

&nbsp;Uncomplicated healing of grafts for tendon reconstruction remains an unsolved problem in hand surgery. Results are limited by adhesion formation and decreased strength properties, especially within the tight fibro-osseous sheath of the digits. This is especially problematic when an extra synovial tendon graft is used to replace an intra synovial flexor tendon. Compositional differences are likely to play an important role in these processes. The aim of this study was, therefore, to compare protein expression in pair-matched intra synovial tendon grafts with extra synovial tendon grafts, using a rabbit tendon injury model. We hypothesized that there would be significant differences in proteins critical for response to tensile loading and adhesion formation between the two groups. Using mass spectrometry and multivariate statistical data analysis, we found tissue-specific differences in 22 proteins, where 7 explained 93% (R2) of the variation, with a prediction of 81% (Q2). Among the highest discriminating proteins were Galectin, Histone H2A, and Periostin, which were found in a substantially larger amount in the extra synovial tendons compared to the intra synovial tendons. These findings may contribute to improved understanding of the differences in outcome seen after tendon reconstruction using tendon grafts with intra synovial and extra synovial grafts.

Objectives: Measurement of perfusion is an established method to evaluate the depth of burns. However, high accuracy is only achievable >48 h after injury. The aim of the study was to investigate if measurement of blood flow pulsatility, combined with perfusion measurement, can improve early assessment of burn depth using laser speckle contrast imaging (LSCI)., Methods: Perfusion and pulsatility were measured with LSCI in 187 regions of interest in 32 patients, between 0 and 5 days after injury. The reproducibility of pulsatility was tested for recording durations between 1 and 12 s. The most reproducible duration was chosen, and receiver operator characteristics were created to find suitable pulsatility cut-offs to predict surgical need., Results: A measurement duration of 8 s resulted in a good reproducibility of the pulsatility (%CV: 15.9%). Longer measurement durations resulted in a small improvement of the accuracy of the assessment. A pulsatility of <1.45 (Perfusion Units) 2 on day 0-2 after injury predicted surgical need with a sensitivity of 100% (95% CI: 83.2-100%), specificity of 100% (95% CI: 95.2-100%), a positive predictive value of 100%, and a negative predictive value of 100%. Pulsatility was not significantly different when comparing measurements done day 0-2 to day 3-5. Perfusion was however significantly higher day 3-5 compared to day 0-2 for wounds healing within 3 weeks., Conclusion: Measurement of pulsatility improves the accuracy of the assessment of burns with LSCI and makes it possible to predict the need for surgery during day 0-2 after injury with a high accuracy., (Copyright © 2020 Elsevier Ltd and ISBI. All rights reserved.)

Introduction: Impaired oxygenation in the skin may occur in disease states and after reconstructive surgery. We used tissue viability imaging (TiVi) to measure changes in oxygenation and deoxygenation of haemoglobin in an in vitro model and in the dermal microcirculation of healthy individuals., Materials and Methods: Oxygenation was measured in human whole blood with different levels of oxygenation. In healthy subjects, changes in red blood cell concentration (C RBC,TiVi ), oxygenation (ΔC OH,TiVi ) and deoxygenation (ΔC DOH,TiVi ) of haemoglobin were measured during and after arterial and venous occlusion using TiVi and were compared with measurements from the enhanced perfusion and oxygen saturation system (EPOS)., Results: During arterial occlusion, C RBC,TiVi remained unchanged while ΔC OH,TiVi decreased to -44.2 (10.4) AU (p = 0.04), as compared to baseline. After release, C RBC,TiVi increased to 39.2 (18.8) AU (p < 0.001), ΔC OH,TiVi increased to 38.5. During venous occlusion, C RBC,TiVi increased to 28.9 (11.2) AU (p < 0.001), ΔC OH,TiVi decreased to -52.2 (46.1) AU (p < 0.001) compared to baseline after 5 min of venous occlusion. There was a significant correlation between the TiVi Oxygen Mapper and EPOS, for arterial (r = 0.92, p < 0.001) and venous occlusion (r = 0.87, p < 0.001), respectively., Conclusion: This study shows that TiVi can measure trends in oxygenation and deoxygenation of haemoglobin during arterial and venous stasis in healthy individuals., Competing Interests: Declaration of competing interest None declared., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Methyl nicotinate (MN) induces a local cutaneous erythema in the skin and may be valuable as a local provocation in the assessment of microcirculation and skin viability. The mechanisms through which MN mediates its vascular effect are not fully known. The aim of this study was to characterize the vasodilatory effects of topically applied MN and to study the involvement of nitric oxide (NO), local sensory nerves, and prostaglandin-mediated pathways., Methods: MN was applied on the skin of healthy subjects in which NO-mediated (L-NMMA), nerve-mediated (lidocaine/prilocaine), and cyclooxygenase-mediated (NSAID) pathways were selectively inhibited. Microvascular responses in the skin were measured using laser speckle contrast imaging (LSCI)., Results: NSAID reduced the MN-induced perfusion increase with 82% (P < .01), whereas lidocaine/prilocaine reduced it with 32% (P < .01). L-NMMA did not affect the microvascular response to MN., Conclusion: The prostaglandin pathway and local sensory nerves are involved in the vasodilatory actions of MN in the skin., (© 2019 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objective: The aim of this study was to investigate whether the effects on local blood flow and metabolic changes observed in the skin after an endogenous systemic increase in insulin are mediated by the endothelial nitric oxide pathway, by administering the nitric oxide synthase inhibitor N G -monomethyl l-arginine using microdialysis., Methods: Microdialysis catheters, perfused with N G -monomethyl l-arginine and with a control solution, were inserted intracutaneously in 12 human subjects, who received an oral glucose load to induce a systemic hyperinsulinemia. During microdialysis, the local blood flow was measured by urea clearance and by laser speckle contrast imaging, and glucose metabolites were measured., Results: After oral glucose intake, microvascular blood flow and glucose metabolism were both significantly suppressed in the N G -monomethyl l-arginine catheter compared to the control catheter (urea clearance: P < .006, glucose dialysate concentration: P < .035). No significant effect of N G -monomethyl l-arginine on microvascular blood flow was observed with laser speckle contrast imaging (P = .81)., Conclusion: Local delivery of N G -monomethyl l-arginine to the skin by microdialysis reduces microvascular blood flow and glucose delivery in the skin after oral glucose intake, presumably by decreasing local insulin-mediated vasodilation., (© 2019 John Wiley & Sons Ltd.)

Background and purpose - Fractures of the distal ulna can occur in isolation or in conjunction with a distal radius fracture. They may result in incongruence and instability of the distal radioulnar joint. We investigated the incidence of distal ulna fractures, whether any fracture types were more common, and the methods of treatment used.Patients and methods - Data were collected from patients 18 years or older, treated for a fracture of the distal ulna in Östergötland, Sweden, during 2010-2012. Patients were identified in the patient registry. The fractures were classified according to the AO comprehensive classification of fractures.Results - The incidence of distal ulna fractures was 74/100,000 person-years. The most common fracture type was that of the ulnar styloid Q1 (79%), followed by the ulnar neck Q2 (11%). Rarest was ulna head fracture, type Q4 (1%). Incidental findings were a mean age of 63 years (SD 18), a concomitant distal radius fracture in 92% of the patients and that 79% were caused by falling from standing height. Internal fixation was performed in 30% of the Q2-Q6 fractures. This indicates that most were considered stable without internal fixation or stable after fixation of a concomitant radius fracture.Interpretation - Our results show that fractures of the distal ulna are not very common, and some fracture types are even rare. There seem to be no consensus on treatment.

Laser speckle contrast imaging (LSCI) is a laser-based perfusion imaging technique that recently has been shown to predict ischemic necrosis in an experimental flap model and predicting healing time of scald burns. The aims were to investigate perfusion in relation to the selected perforator during deep inferior epigastric artery perforator (DIEP) flap surgery, and to evaluate LSCI in assisting of prediction of postoperative complications., Methods: Twenty-three patients who underwent DIEP-procedures for breast reconstruction at 2 centers were included. Perfusion was measured in 4 zones at baseline, after raising, after anastomosis, and after shaping the flap. The perfusion in relation to the selected perforator and the accuracy of LSCI in predicting complications were analyzed., Results: After raising the flap, zone I showed the highest perfusion (65 ± 10 perfusion units, PU), followed by zone II (58 ± 12 PU), zone III (53 ± 10 PU), and zone IV (45 ± 10 PU). The perfusion in zone I was higher than zone III ( P = 0.002) and zone IV ( P < 0.001). After anastomosis, zone IV had lower perfusion than zone I ( P < 0.001), zone II ( P = 0.01), and zone III ( P = 0.02). Flaps with areas <30 PU after surgery had partial necrosis postoperatively (n = 4)., Conclusions: Perfusion is highest in zone I. No perfusion difference was found between zones II and III. Perfusion <30 PU after surgery was correlated with partial necrosis. LSCI is a promising tool for measurement of flap perfusion and assessment of risk of postoperative ischemic complications., (Copyright © 2020 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of The American Society of Plastic Surgeons.)