Purpose If early active motion after 3-ligament tenodesis is safe, it may yield more patient comfort and an early return to activities. Therefore, the aim of this study was to investigate whether early active motion is noninferior to late active motion after 3-ligament tenodesis for scapholunate interosseous ligament injuries.Methods This prospective, multicenter cohort study, using a noninferiority design with pro-pensity score matching, compared a late active motion protocol (immobilization for 10-16 days, wrist therapy in weeks 5-6) with an early active motion protocol (immobilization for 3-5 days, wrist therapy during week 2). Patients who were older than 18 years, had complete baseline information on demographics, and underwent 3-ligament tenodesis were included. The outcome measures were postoperative Patient-Reported Wrist/Hand Evaluation scores, pain, complications, return to work, range of motion, grip strength, and satisfaction with treatment results at 3 months of follow-up.Results After propensity matching, a total of 108 patients were included. Patient-Reported Wrist/Hand Evaluation and pain scores during physical load following an early active mo-tion protocol were noninferior compared with scores following a late active motion protocol. Furthermore, early active motion did not lead to an increase of complications, differences in range of motion or grip strength, or less satisfaction with the treatment result. An earlier return to work was not observed.Conclusions Early active motion leads to noninferior results without more complications as compared with late active motion. Based on these findings, early active motion can be considered safe, and might be recommended due to its potential benefits compared with late active motion after 3-ligament tenodesis. (J Hand Surg Am. 2022;47(11):1076-1084.Copyright (c) 2022 by the American Society for Surgery of the Hand. All rights reserved.)Type of study/level of evidence Therapeutic III.

Objective People in the Netherlands are legally allowed to celebrate New Year's Eve with consumer fireworks. The aim of this study was to provide detailed information about the patient and injury characteristics, medical and societal costs, and clinical and functional outcome in patients with injuries resulting from this tradition. Methods A multicenter, prospective, observational case series performed in the Southwest Netherlands trauma region, which reflects 15% of the country and includes a level I trauma center, a specialized burn center, a specialized eye hospital, and 13 general hospitals. All patients with any injury caused by consumer fireworks, treated at a Dutch hospital between December 1, 2017 and January 31, 2018, were eligible for inclusion. Exclusion criteria were unknown contact information or insufficient understanding of Dutch or English language. The primary outcome measure was injury characteristics. Secondary outcome measures included treatment, direct medical and indirect societal costs, and clinical and functional outcome until one year after trauma. Results 54 out of 63 eligible patients agreed to participate in this study. The majority were males (N = 50; 93%), 50% were children below 16 years of age, and 46% were bystanders. Injuries were mainly located to the upper extremity or eyes, and were mostly burns (N = 38; 48%) of partial thickness (N = 32; 84%). Fifteen (28%) patients were admitted and 11 (20%) patients needed surgical treatment. The mean total costs per patient were €6,320 (95% CI €3,400 to €9,245). The most important cost category was hospital admission. Only few patients reported complaints in patient-reported quality of life and functional outcome after 12 months follow-up. Conclusion This study found that young males are most vulnerable for fireworks injuries and that most injuries consist of burns, located to the arm and hand, and eye injuries. On the long-term only few patients experienced reduced quality of life and functional limitations.

This study investigates the outcomes of 1106 patients with Dupuytren’s disease treated with limited fasciectomy or percutaneous needle fasciotomy over 16 years according to the different domains of patient-reported hand function. These patients completed the Michigan Hand Outcomes Questionnaire before and 3 months after surgery. Scores for the various outcome parameters were calculated and linear regression analyses were used to examine associations between the changes in digital extension deficit and change in Michigan Hand Outcomes Questionnaire (sub)scores. We found the largest effects of surgical treatment in the decreases in extension deficit, the appearance of the hand, and the satisfaction with the hand function. However, associations between different domains of evaluation were weak. We conclude that improvement of digital extension deficits is not parallel to varying aspects of patient satisfaction. The findings underline the importance of assessing domains relating to patient satisfaction other than objective hand function measures in Dupuytren’s disease. Level of evidence: IV

The aim of this study was to investigate the association between patients' experiences with trapeziometacarpal arthroplasty and treatment outcomes in terms of patient-reported outcome measures, grip and pinch strength. We included 233 patients who received a Weilby procedure for trapeziometacarpal osteoarthritis. Before surgery and 12 months after surgery, patients completed the Michigan Hand Outcomes Questionnaire, and their pinch and grip strengths were measured. At 3 months after surgery, a patient-reported experience measure was completed. Using regression analysis, significantly positive associations were found between the Michigan Hand questionnaire and the patient-reported experience measure, with the strongest significant associations being for patients' experiences with information provision. No significant associations were found between the patients' experience and strength outcomes. The results highlight the potential importance of positive experience with the treatment process to improve treatment outcomes in patients undergoing surgery for trapeziometacarpal osteoarthritis. Level of evidence: IV.

Abstract Background The aim of this study was to investigate to what extent psychological factors are related to pain levels prior to non-invasive treatment in patients with osteoarthritis of the first carpometacarpal joint. Methods We included patients (n = 255) at the start of non-invasive treatment for osteoarthritis of the first carpometacarpal joint who completed the Michigan Hand Outcome Questionnaire. Psychological distress, pain catastrophizing behavior and illness perception was measured. X-rays were scored on presence of scaphotrapeziotrapezoid osteoarthritis. We used hierarchical linear regression analysis to determine to what extent pain levels could be explained by patient characteristics, X-ray scores, and psychological factors. Results Patient characteristics and X-ray scores accounted for only 6% of the variation in pre-treatment pain levels. After adding the psychological factors to our model, 47% of the variance could be explained. Conclusions Our results show that psychological factors are more strongly related to pain levels prior to non-invasive treatment in patients with osteoarthritis of the first carpometacarpal joint than patient characteristics and X-ray scores, which implies the important role of these factors in the reporting of symptoms. More research is needed to determine whether psychological factors will also affect treatment outcomes for patients treated non-invasively for osteoarthritis of the first carpometacarpal joint. IMPLICATIONS FOR REHABILITATION Pain is the most important complaint for patients with osteoarthritis of the first carpometacarpal joint. Psychological factors are strongly associated with pain levels prior to treatment. Pain catastrophizing behavior appears to be a promising target for complementary treatment in patients with osteoarthritis of the first carpometacarpal joint.

OBJECTIVE:The aim of this study was to evaluate the self-reported outcome of revision surgery in patients with recurrent and persistent carpal tunnel syndrome (CTS) and to identify predictors of clinical outcome of revision surgery. METHODS:A total of 114 hands in 112 patients were surgically treated for recurrent and persistent CTS in one of 10 specialized hand clinics. As part of routine care, patients were asked to complete online questionnaires regarding demographic data, comorbidities, and clinical severity measures. The Boston Carpal Tunnel Questionnaire (BCTQ) was administered at intake and at 6 months postoperatively to evaluate clinical outcome. The BCTQ comprises the subscales Symptom Severity Scale (SSS) and Functional Status Scale (FSS), and the individual scores were also assessed. Using multivariable regression models, the authors identified factors predictive of the outcome as measured by the BCTQ FSS, SSS, and total score at 6 months. RESULTS:Revision surgery significantly improved symptoms and function. Longer total duration of symptoms, a higher BCTQ total score at intake, and diagnosis of complex regional pain syndrome (CRPS) along with CTS were associated with worse outcome after revision surgery at 6 months postoperatively. The multivariable prediction models could explain 33%, 23%, and 30% of the variance in outcome as measured by the FSS, SSS, and BCTQ total scores, respectively, at 6 months. Although patients with higher BCTQ scores at intake have worse outcomes, they generally have the most improvement in symptoms and function. CONCLUSIONS:This study identified total duration of symptoms, BCTQ total score at intake, and diagnosis of CRPS along with CTS as predictors of clinical outcome and confirmed that revision surgery significantly improves self-reported symptoms and function in patients with recurrent and persistent CTS. Patients with more severe CTS symptoms have greater improvement in symptoms at 6 months postoperatively than patients with less severe CTS, but 80% of patients still had residual symptoms 6 months postoperatively. These results can be used to inform both patient and surgeon to manage expectations on improvement of symptoms.

OBJECTIVE:To compare the effect of exercises and orthotics with orthotics alone on pain and hand function in patients with first carpometacarpal joint (CMC-1) osteoarthritis (OA) and to predict outcomes on pain and hand function of exercises and orthotics.DESIGN:Prospective cohort study with propensity score matching.SETTING:Data collection took place in 13 outpatient clinics for hand surgery and hand therapy in The Netherlands.PARTICIPANTS:A consecutive, population-based sample of patients with CMC-1 OA (N=173) was included in this study, of which 84 were matched on baseline demographics and baseline primary outcomes.INTERVENTIONS:Exercises and orthotics versus orthotics alone.MAIN OUTCOME MEASURES:Primary outcomes included pain and hand function at 3 months, measured using visual analog scale (VAS, 0-100) and the Michigan Hand Outcomes Questionnaire (MHQ, 0-100).RESULTS:A larger decrease in VAS pain at rest (11.1 points difference; 95% confidence interval, 1.9-20.3; P=.002) and during physical load (22.7 points difference; 95% confidence interval, 13.6-31.0; P<.001) was found in the exercise + orthotic group compared to the orthotic group. In addition, larger improvement was found for the MHQ subscales pain, work performance, aesthetics, and satisfaction in the exercise + orthotic group. No differences were found on other outcomes. Baseline scores of metacarpophalangeal flexion, presence of scaphotrapeziotrapezoid OA, VAS pain at rest, heavy physical labor, and MHQ total predicted primary outcomes for the total exercise + orthotic group (N=131).CONCLUSIONS:Non-surgical treatment of patients with CMC-1 OA should include exercises, since there is a relatively large treatment effect compared to using an orthosis alone. Future research should study exercises and predictors in a more standardized setting to confirm this finding.

Background: Although previous studies have shown that more experienced surgeons have better patient outcomes following a variety of procedures, in hand surgery and carpal tunnel release in particular, this relation remains unproven. The authors assessed whether there is an association between surgeon volume and patient outcomes following open carpal tunnel release. Methods: Patients who underwent carpal tunnel release between 2011 and 2015 at outpatient hand surgery clinics in The Netherlands were included. Surgeon annual volume was defined as the average number of carpal tunnel releases performed per year per participating surgeon over the study period. Primary outcome measures were the Symptom Severity Scale and Functional Status Scale of the Boston Carpal Tunnel Questionnaire 6 months postoperatively. Multilevel random intercept linear regression analyses were performed to assess whether there was an association between surgeon annual volume and outcome measures, with adjustment for patient characteristics, concomitant procedures, and intake score on the Boston Carpal Tunnel Questionnaire. Results: A total of 1345 patients were included, operated on by 17 surgeons. Median annual surgeon volume was 75 (interquartile range, 50 to 149). Only 0.5 to 0.6 percent of the total variance in patient outcome on the Boston Carpal Tunnel Questionnaire could be explained by random differences between surgeons. The authors did not find an association between annual surgeon volume and outcome measures 6 months postoperatively (Symptom Severity Scale: β = 0.000; 95 percent CI, −0.001 to 0.001; and Functional Status Scale: β = 0.000; 95 percent CI, −0.001 to 0.001). Conclusion: In the authors’ sample of highly specialized hand surgeons operating in high-volume centers, they found no differences in outcome between high- and low-volume surgeons.

OBJECTIVE: To report the number of patients with firework-related injuries treated in December 2017 and January 2018 in a hospital in the south-west Netherlands trauma region, and to provide details about the types of firework used and the specific injuries. DESIGN: A prospective multicentre cohort study (NTR6793). METHODS: Patients of all ages with firework-related injuries were eligible for inclusion. The injury had to have been sustained between 1 December 2017 and 31 January 2018, and treated at a hospital in the south-west Netherlands trauma region (approximately 2.5 million inhabitants). Data were extracted from patients' medical files and additional information was obtained from patient interviews. RESULTS: Fifty-four patients were included. The majority were male (93%) and the median age was 15 years. Twenty-five (46%) patients were bystanders and 12 (22%) were injured by illegal fireworks. Fifty patients were injured by bangers (n=22) or decorative fireworks (n=28). The patients had a total of 79 injuries, of which 29 (37%) were localised to the upper extremity and 19 (24%) to the eyes. Most upper extremity injuries were burns (69%), primarily partial thickness. Of the eye injuries, 14 were caused by blunt trauma, seven by chemical trauma, and one by penetrating trauma. Three patients sustained indirect firework-related injuries. CONCLUSION: Between 1 December 2017 and 31 January 2018 in the south-west Netherlands trauma region mainly teenage males and bystanders sustained firework-related injuries. Most injuries were upper extremity burns and eye injuries, mainly due to legal fireworks and bangers or decorative fireworks. The extent of the sample indicat

Doel Een volledig overzicht geven van het aantal vuurwerkslachtoffers dat in december 2017 en januari 2018 behandeld werd in een ziekenhuis in de traumaregio Zuidwest-Nederland, het gebruikte soort vuurwerk en de specifieke letsels. Opzet Een prospectieve, multicentrische cohortstudie (NTR6793). Methode Patienten van alle leeftijden met vuurwerkletsel kwamen in aanmerking voor inclusie. Het letsel moest zijn ontstaan in de periode 1 december 2017-31 januari 2018 en zijn behandeld in een ziekenhuis in de traumaregio Zuidwest-Nederland (circa 2,5 miljoen inwoners). Gegevens werden verzameld vanuit het patientendossier en aanvullende gegevens werden verkregen tijdens een interview. Resultaten Er werden 54 patienten geincludeerd. Het overgrote deel betrof mannen (93%) en de mediane leeftijd was 15 jaar. 25 gewonden (46%) waren omstander en 12 mensen (22%) raakten gewond door illegaal vuurwerk. Van de 54 patienten raakten er 50 gewond door knalvuurwerk (n = 22) of siervuurwerk (n = 28). De 54 geincludeerde patienten hadden 79 letsels; het letsel was 29 keer (37%) gelokaliseerd aan armen of handen en 19 keer (24%) aan de ogen. Letsel aan de arm of hand bestond voornamelijk uit brandwonden (69%), met name tweedegraads. Oogletsel werd 14 keer door stomp inwerkend geweld veroorzaakt, 7 keer door chemisch letsel en 1 keer werd het oog gepenetreerd. Er raakten 3 patienten indirect gewond door vuurwerk. Conclusie In de traumaregio Zuidwest-Nederland raakten in de 2 maanden rond de jaarwisseling 2017-2018 vooral minderjarige mannen en omstanders gewond. Slachtoffers liepen met name brandwonden aan armen of handen of oogletsel op. De verwondingen waren met name het gevolg van legaal knal- en siervuurwerk. Door de omvang van de steekproef lijken de studiebevindingen goed te extrapoleren naar het gehele land.

OBJECTIVE:To report the number of patients with firework-related injuries treated in December 2017 and January 2018 in a hospital in the south-west Netherlands trauma region, and to provide details about the types of firework used and the specific injuries.DESIGN:A prospective multicentre cohort study (NTR6793).METHODS:Patients of all ages with firework-related injuries were eligible for inclusion. The injury had to have been sustained between 1 December 2017 and 31 January 2018, and treated at a hospital in the south-west Netherlands trauma region (approximately 2.5 million inhabitants). Data were extracted from patients' medical files and additional information was obtained from patient interviews.RESULTS:Fifty-four patients were included. The majority were male (93%) and the median age was 15 years. Twenty-five (46%) patients were bystanders and 12 (22%) were injured by illegal fireworks. Fifty patients were injured by bangers (n=22) or decorative fireworks (n=28). The patients had a total of 79 injuries, of which 29 (37%) were localised to the upper extremity and 19 (24%) to the eyes. Most upper extremity injuries were burns (69%), primarily partial thickness. Of the eye injuries, 14 were caused by blunt trauma, seven by chemical trauma, and one by penetrating trauma. Three patients sustained indirect firework-related injuries.CONCLUSION:Between 1 December 2017 and 31 January 2018 in the south-west Netherlands trauma region mainly teenage males and bystanders sustained firework-related injuries. Most injuries were upper extremity burns and eye injuries, mainly due to legal fireworks and bangers or decorative fireworks. The extent of the sample indicates that the study findings can be extrapolated to the rest of the Netherlands.

Background: This study examined patient satisfaction with hand function after fasciectomy for Dupuytren’s contracture and determined which preoperative patient- and disease-specific factors predicted this satisfaction. Methods: Demographics and disease-specific factors were assessed from a prospective cohort of 194 patients who completed the Michigan Hand Outcomes Questionnaire preoperatively and underwent limited fasciectomy between 2011 and 2014 at six hand surgery practice sites. To evaluate satisfaction with hand function, patients were asked to complete the Michigan Hand Outcomes Questionnaire during the first year after fasciectomy. After patients were classified into a satisfied and an unsatisfied category using the question that specifically pertains to satisfaction with hand function, the authors applied multivariate logistic regression modeling to identify independent predictors of patient satisfaction. Results: At an average of 10 months (range, 6 to 12 months) after fasciectomy, 84 percent (n = 163) of the patients were satisfied with their hand function. In multivariate analyses adjusting for the degree of postoperative residual contracture (p < 0.001) and complications (p < 0.001), a higher preoperative Michigan Hand Outcomes Questionnaire hand appearance subscore and male gender predicted a higher likelihood of becoming satisfied after fasciectomy. Other patient- and disease-specific factors did not show evidence for an association with patient satisfaction. Conclusions: The findings of this study suggest that providers should consider assessing concerns about the appearance of the hand in patients with Dupuytren’s contracture. They also highlight the importance of complication prevention and full contracture correction from the patient’s perspective. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, III.

背景手术切除治疗掌腱膜挛缩症复发率高且康复时间延长.本文将介绍一种新型微创手术替代治疗掌腱膜挛缩症的方法及其成果.方法 过程包括采用广泛经皮针刀筋膜切断术将束带完全松解,并与真皮分离.随后,由此产生的松弛组织用以自体脂肪填充.术后伸直位制动1周,然后,建议术后3～6个月患者白天可以正常用手,夜间伸直位固定.本组患者共91例(99只手),手术在迈阿密和鹿特丹进行;对50例患者的手部伸展角度进行测量(平均随访44周).结果 近端指间关节挛缩的治疗效果显著,伸展角度由61°改善至27°,掌指关节挛缩的伸展角度由37°改善至-5°.94%患者在2～4周内手部恢复正常功能,95%患者对结果非常满意.无新的瘢痕生成,大部分恢复了柔软的手掌脂肪垫.发生了1例神经损伤的并发症,1例术后切口感染,4例复杂区域疼痛综合征.结论 这一新的微创技术缩短了康复时间,增加了缺损的皮下脂肪组织,产生了柔软无痕的皮肤.并且有能力处理多个掌指纹,可解决整只手的异常情况.治疗过程安全有效,尤其对首次治疗者.目前,前瞻性随机对照研究过程充分确定了其治疗掌腱膜挛缩症的作用.(循证医学证据等级:Ⅳ级,疗法)

OBJECT:Extradural and intraneural scar formation after peripheral nerve injury frequently causes tethering and compression of the nerve as well as inhibition of axonal regeneration. Regenerating agents (RGTAs) mimic stabilizing and protective properties of sulphated glycosaminoglycan toward heparin-binding growth factors. The aim of this study was to assess the effect of an RGTA known as OTR4120 on extraneural fibrosis and axonal regeneration after crush injury in a rat sciatic nerve model.METHODS:Thirty-two female Wistar rats underwent a standardized crush injury of the sciatic nerve. The animals were randomly allocated to RGTA treatment or sham treatment in a blinded design. To score neural adhesions, the force required to break the adhesions between the nerve and its surrounding tissue was measured 6 weeks after nerve crush injury. To assess axonal regeneration, magnetoneurographic measurements were performed after 5 weeks. Static footprint analysis was performed preoperatively and at Days 1, 7, 14, 17, 21, 24, 28, 35, and 42 postoperatively.RESULTS:The magnetoneurographic data show no significant difference in conduction capacity between the RGTA and the control group. In addition, results of the static footprint analysis demonstrate no improved or accelerated recovery pattern. However, the mean pullout force of the RGTA group (67 +/- 9 g [mean +/- standard error of the mean]) was significantly (p < 0.001) lower than that of the control group (207 +/- 14 g [mean +/- standard error of the mean]).CONCLUSIONS:The RGTAs strongly reduce nerve adherence to surrounding tissue after nerve crush injury.

Aims: Extra- and intraneural scar formation after peripheral nerve injury frequently causes tethering and compression of the nerve as well as inhibition of axonal regeneration. ReGeneraTing Agents (RGTAs) mimic the stabilizing and protective properties of sulphated glycosaminoglycan (GAG) towards heparin-binding growth factors (HBGFs). The aim of this study was to assess the effect of a RGTA, named OTR4120, on extraneural fibrosis and axonal regeneration after crush injury in a rat sciatic nerve model.

textabstractHet klinisch herstel na letsel van een perifere zenuw is matig. Een groeiende kennis op het gebied van de (patho)fysiologie van de neurobiologie vertaalt zich maar deels in een functionele verbetering na perifeer zenuwletsel. Het proefdiermodel speelt een cruciale rol in deze vertaalslag. Klinisch onderzoek op het gebied zenuwletsel wordt bemoeilijkt door heterogeniteit van letsels en patientenpopulatie. Gerichte en kwantitatieve evaluatietechnieken van perifeer zenuwletsel in een proefdiermodel maken de uiteindelijke stap naar een klinische setting kleiner en/of makkelijker. De nervus ischiadicus van de rat is een veel gebruikt experimenteel model voor het evalueren van perifeer zenuwletsel. Het doel van dit proefschrift is middels het rattenmodel (patho)fysiologische processen, die zich afspelen op de plek van het letsel, in kaart te brengen en in getal uit te kunnen drukken. Een ex vivo model is ontwikkeld waarin neurofysiologische metingen plaatsvinden. Magnetoneurografie (MNG) is een techniek waarin biomagnetische velden van een geleidende zenuw worden gemeten, om zodoende de geleidingscapaciteit van een (ratten)zenuw te bepalen. MNG metingen van relatief kleine rattenzenuwen blijken in een ex vivo meetbad zeer reproduceerbaar en accuraat. Het looppatroon van de rat geldt al jaren als functionele maat voor herstel van de zenuw in een rattenmodel. Een vereenvoudigde methode van deze tijdrovende functie analyse is onderzocht. Statische voetzool analyse is een efficiente vervanger van de oude looppatroon analyse. Het herstel in tijd, na doorsnijding van een rattenzenuw, is onderzocht middels MNG, statische voetzool analyse en spiergewicht analyse. Er bestaat een evident verschil tussen het herstelpatroon van MNG en het herstel van het voetzoolpatroon. Verschillen en tekortkomingen van indirecte evaluatiemethoden (voetzool analyse en spiergewicht) t.o.v. een directe evaluatiemethode (MNG) van de geleidingscapaciteit van een zenuw worden uitgebreid besproken. Een zenuw kan niet worden beschouwd als een elastiek. Een biomechanische studie naar rattenzenuwen laat zien dat de rekbaarheid van een zenuw verschilt per zenuwsegment en afhangt van de nabijheid van een gewricht. Verklevingen van zenuwen met omliggend weefsel zijn een groot klinisch probleem. Experimentele technieken om dit anti adhesieve middelen te testen hebben ernstige beperkingen. Een biomechanisch model is ontwikkeld waarin neurale verklevingen kwantitatief en objectief kunnen worden vastgelegd in het rattenmodel. De anti adhesieve werking van Hyaluronzuur gel en RGTA worden met dit model aangetoond na diverse soorten zenuwletsel. Dit proefschrift omvat een overzicht van alle gangbare evaluatiemethoden van zenuwletsel, die beschikbaar zijn in een experimentele setting. In de diverse hoofdstukken worden tekortkomingen uitgelicht en worden oplossingen aangedragen in de vorm van nieuw ontwikkelde experimentele modellen (neurofysiologisch, functioneel, biomechanisch). Deze modellen worden gebruikt om op een gerichte wijze en kwantitatief strategieen te testen die het herstel na zenuwletsel kunnen beinvloeden.

Experimental assessment of peripheral nerve regeneration in rats by electrophysiology is controversial due to low reproducibility of electrophysiological indicators and diminished quantitative evaluation in conventional experimental set-ups. Magnetoneurography (MNG) counteracts these drawbacks by magnetically recording electrophysiological signals ex vivo, thereby providing accurate and quantitative data. In 50 rats, sciatic nerve transection was followed by direct repair. MNG outcome parameters, footprints [static toe spread factor (TSF); function] and muscle weight (MW) were studied for their recovery pattern from 2 to 24 weeks. By using MNG, we showed that the regeneration process still continues when functional recovery (static TSF) becomes stagnant. With regression analysis, MNG parameters amplitude, amplitude area and conduction velocity (CV) demonstrated moderate significant correlation with MW, whereas CV was not significantly associated with static TSF. No significant association exists between MW and static TSF. A Kaplan-Meier survival curve revealed that autotomy/contracture of rat hind paws was not related to decreased MNG outcome values. In conclusion, this study highlights and discusses the dissimilarities between direct (MNG) and indirect (static TSF and MW) assessment techniques of the regeneration process. We emphasise the significance of MNG as a direct derivative of axon regeneration in experimental rat studies. Additionally, we stress the must for right-left ratios, as neurophysiological indicators vary with age, and we confute possible bias in footprint analysis caused by exclusion of autotomy/contracture animals.

Walking track analysis is a widely accepted technique for functional evaluation after sciatic nerve repair in rats, but it is labour-intensive. In 2000, Bervar described a time-saving digitised static footprint analysis. In that study there were good correlations between the traditional sciatic function index (SFI) and the newly-developed static sciatic index (SSI) and static toe spread factor (TSF), respectively. Despite promising results, static footprint analysis is still not widely used. The present study was designed to validate it. After transection of the sciatic nerve, end-to-end repair was assessed using video recorded dynamic and static footprints in 45 Wistar rats. We found an even better correlation between the SFI and both the SSI and the static TSF. In conclusion, static footprint analysis is a time-saving and easy technique for accurate functional assessment of peripheral nerve regeneration in rats.

OBJECTAdhesion formation is a serious problem in peripheral nerve surgery, frequently causing dysfunction and pain. The authors aimed to develop an objective biomechanical method of quantifying nerve adhesions and to use this technique for the evaluation of the efficacy of an autocrosslinked hyaluronic acid (HA) gel as an antiadhesion therapy.METHODSThirty-three female Wistar rats underwent dissection, crush injury, or transection plus repair of the sciatic nerve. The nerves were or were not treated with the HA gel. Six weeks after surgery, the adhesions formed were assessed by measuring the peak force required to break the adhesions over a standardized area. Results of biomechanical measurements demonstrated that the peak force significantly increased as the severity of the injury increased. After using the HA gel to treat the nerve, the peak force was significantly reduced in rats with any of the three types of injuries; peak force decreased by 26% in the animals in the dissection group, 29% in the crush injury group, and 38% in the transection and repair group, compared with the untreated animals.CONCLUSIONSThe biomechanical method described is an objective, quantitative technique for the assessment of nerve adherence to surrounding tissue. It will be a valuable tool in future studies on antiadhesion therapies. Furthermore, HA gel significantly reduces nerve adhesions after different types of nerve injuries.

Peripheral nerves in the limbs stretch to accommodate changes in length during normal movement. The aim of this study was to determine how stretch is distributed along the nerve relative to local variations in mechanical properties. Deformation (strain) in joint and non‐joint regions of rat median and sciatic nerves was measured in situ during limb movement using optical image analysis. In each nerve the strain was significantly greater in the joint rather than the non‐joint regions (2‐fold in the median nerve, 5‐ to 10‐fold in the sciatic). In addition, this difference in strain was conserved in the median nerve ex vivo, demonstrating an in‐built longitudinal heterogeneity of mechanical properties. Tensile testing of isolated samples of joint and non‐joint regions of both nerves showed that joint regions were less stiff (more compliant) than their non‐joint counterparts with joint: non‐joint stiffness ratios of 0.5 ± 0.07 in the median nerve, and 0.8 ± 0.02 in the sciatic. However, no structural differences identified at the light microscope level in fascicular/non‐fascicular tissue architecture between these two nerve regions could explain the observed tensile heterogeneity. This identification of localized functional heterogeneity in tensile properties is particularly important in understanding normal dynamic nerve physiology, provides clues to why peripheral nerve repair outcomes are variable, and suggests potential novel therapeutic targets.