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Purpose: Surgical performance that improves with experience is often depicted as representing a "learning curve." Although numerous studies examine the tensile properties of various flexor tendon repairs, few compare the associated learning curves. This study aims to address this gap by comparing the learning curves of Adelaide- and Gan-modified Lim-Tsai repairs. Emphasizing the difference in learning curves is crucial because it highlights the tension between achieving biomechanically superior repairs, which may be challenging to many surgeons, and opting for possibly incrementally less strong but more feasible techniques., Methods: We organized a workshop attended by 20 medical students whose experience in surgery was limited to a few suturing exercises. Each participant repaired five porcine tendons in situ either with Adelaide- or Gan-modified Lim-Tsai, followed by a peripheral suture. We tested all tendons with linear static testing to measure ultimate and yield loads. In addition, repair times were recorded for each repair. We used a linear mixed model to compare learning between the techniques., Results: Ultimate loads increased with experience and were higher in Adelaide technique during the first two repairs, compared with Gan-modified Lim-Tsai (80 N vs 63 N and 79 N vs 66 N, respectively). Yield loads also increased with experience but did not differ between the repair techniques at any time point. Mean repair times decreased from 44 to 28 minutes and from 46 to 25 minutes with Adelaide- and Gan-modified Lim-Tsai repairs, respectively., Conclusions: The Adelaide core suture had a higher initial ultimate load capacity despite fewer suture strands, possibly indicating better tension consistency. The ultimate load of the Gan-modified Lim-Tsai repair increased between the first and fifth repair, and repeats were needed to achieve comparable results with the Adelaide repair., Clinical Relevance: The results of this study suggest that both repair methods are suitable for novice surgeons, but Adelaide tends to result in higher strength from the first repair. Generalizability to other repairs should be made with caution., 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.)

This study evaluates the long-term donor site outcomes after second toe transfers for congenital hand differences performed during childhood. In total, 25 toe transfers in 18 patients were followed up for a mean period of 17.4 years. We examined the patients clinically, radiologically and with a gait analysis system. Patient-reported outcome measures were collected. The patients were asymptomatic and there were no problematic clinical or radiological findings. Patients expressed high levels of satisfaction. The results were consistent, regardless of the resection level in the toe transfer or whether the operation was unilateral or bilateral. No postoperative complications or late reoperations on the foot were observed. Level of evidence IV., 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: Replantation is an established treatment for traumatic upper extremity amputation. Only a few studies, however, have assessed the patient-reported outcomes of replantation, and the findings of these studies have been conflicting., Questions/purposes: (1) Is replantation associated with better hand function than revision amputation? (2) Is replantation associated with better health-related quality of life, less painful cold intolerance, and more pleasing hand esthetics than revision amputation after a traumatic hand amputation?, Methods: In this retrospective, comparative study, we collected the details of all patients who sustained a traumatic upper extremity amputation and were treated at the study hospital. Between 2009 and 2019, we treated 2250 patients, and we considered all patients who sustained a traumatic amputation of two or more digital rays or a thumb as potentially eligible. Based on that, 15% (334 of 2250) were eligible; a further 2% (8 of 334) were excluded because of a subsequent new traumatic amputation or bilateral amputation, and another 22% (72 of 334) refused participation, leaving 76% (254 of 334) for analysis here. The primary outcome was the DASH score. Secondary outcomes included health-related quality of life (EuroQOL-5D [EQ-5D-5L] Index), painful cold intolerance (the Cold Intolerance Symptom Severity score), and hand esthetics (the Michigan Hand Questionnaire aesthetic domain score). The minimum follow-up time for inclusion was 18 months. Patients were classified into two treatment groups: replantation (67% [171 of 254], including successful replantation in 84% [144 of 171] and partially successful replantation in 16% [27 of 171], in which some but not all of the replanted tissue survived), and revision (complete) amputation (33% [83 of 254], including primary revision amputation in 70% [58 of 83] and unsuccessful replantation followed by secondary amputation in 30% [25 of 83]). In this cohort, replantation was performed if possible, and the reason for choosing primary revision amputation over replantation was usually an amputated part that was too severely damaged (15% [39 of 254]) or was unattainable (2% [4 of 254]). Some patients (3% [8 of 254]) refused to undergo replantation, or their health status did not allow replantation surgery and postoperative rehabilitation (3% [7 of 254]). Gender, age (mean 48 ± 17 years in the replantation group versus 50 ± 23 years in the revision amputation group; p = 0.41), follow-up time (8 ± 4 years in the replantation group versus 7 ± 4 years in the revision amputation group; p = 0.18), amputation of the dominant hand, smoking, extent of tissue loss, or presence of arterial hypertension did not differ between the groups. Patients in the replantation group less frequently had diabetes mellitus (5% [8 of 171] versus 12% [10 of 83]; p = 0.03) and dyslipidemia (4% [7 of 171] versus 11% [9 of 83]; p = 0.04) than those in the revision group and more often had cut-type injuries (75% [129 of 171] versus 60% [50 of 83]; p = 0.02)., Results: After controlling for potential confounding variables such as age, injury type, extent of tissue loss before treatment, and accident of the dominant hand, replantation was not associated with better DASH scores than revision amputation (OR 0.82 [95% confidence interval (CI) 0.50 to 1.33]; p = 0.42). After controlling for potential cofounding variables, replantation was not associated with better EQ-5D-5L Index scores (OR 0.93 [95% CI 0.56 to 1.55]; p = 0.55), differences in Cold Intolerance Symptom Severity scores (OR 0.85 [95% CI 0.51 to 1.44]; p = 0.79), or superior Michigan Hand Questionnaire esthetic domain scores (OR 0.73 [95% CI 0.43 to 1.26]; p = 0.26) compared with revision amputation., Conclusion: Replantation surgery was conducted, if feasible, in a homogenous cohort of patients who underwent amputation. If the amputated tissue was too severely damaged or replantation surgery was unsuccessful, the treatment resulted in revision (complete) amputation, which was not associated with worse patient-reported outcomes than successful replantation. These results contradict the assumed benefits of replantation surgery and indicate the need for credible evidence to better guide the care of these patients., Level of Evidence: Level III, therapeutic study., Competing Interests: Each author certifies that there are no funding or commercial associations (consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article related to the author or any immediate family members. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research® editors and board members are on file with the publication and can be viewed on request., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the Association of Bone and Joint Surgeons.)

Background: Surgery, needle fasciotomy, and collagenase injection are used to treat Dupuytren contracture. The treatment decision requires balancing initial morbidity and costs of surgery against its potential long-term benefits over needle fasciotomy and collagenase., Objective: To compare the effectiveness of surgery, needle fasciotomy, and collagenase injection at 3 months and 2 years (secondary time points of the trial)., Design: A multicenter, randomized, outcome assessor-blinded, superiority trial. (ClinicalTrials.gov: NCT03192020)., Setting: 6 public hospitals in Finland., Participants: 302 persons with treatment-naive Dupuytren contracture (contracture angle <135°)., Intervention: Surgery ( n  = 101), needle fasciotomy ( n  = 101), or collagenase ( n  = 100)., Measurements: The primary outcome was the success rate, defined as greater than 50% contracture release and patients reaching the patient acceptable symptom state. Secondary outcomes included hand function, pain, quality of life, patient satisfaction, residual contracture angle, finger flexion, risk for retreatment, and serious adverse events., Results: A total of 292 (97%) and 284 (94%) participants completed the 3-month and 2-year follow-ups. Success rates were similar at 3 months: 71% (95% CI, 62% to 80%) for surgery, 73% (CI, 64% to 82%) for needle fasciotomy, and 73% (CI, 64% to 82%) for collagenase. At 2 years, surgery had superior success rates compared with both needle fasciotomy (78% vs. 50%; adjusted risk difference [aRD], 0.30 [CI, 0.17 to 0.43]) and collagenase (78% vs. 65%; aRD, 0.13 [CI, 0.01 to 0.26]). Secondary analyses paralleled with the primary analysis., Limitation: Participants were not blinded., Conclusion: Initial outcomes are similar between the treatments, but at 2 years success rates were maintained in the surgery group but were lower with both needle fasciotomy and collagenase despite retreatments., Primary Funding Source: Research Council of Finland., Competing Interests: Disclosures: Disclosures can be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=M23-1485.

The aim of this study was to compare the consistency and reliability of the six-strand Gan modification of the Lim-Tsai flexor tendon repair with the four-strand Adelaide repair, both with 3-0 sutures and with eight to ten runs of simple 5-0 running peripheral suture as well as the influence of the surgeons' level of experience on the strength of the repair in a cadaveric animal setup. Thirty-nine surgeons repaired 78 porcine flexor digitorum profundus tendons with either the Adelaide technique (39 tendons) or the modified Lim-Tsai technique (39 tendons). Each repaired tendon was tested in a material testing machine under a single cycle load-to-failure test. The forces were recorded when the gap between the two tendon stumps reached 1 and 2 mm and when irreversible elongation or total rupture occurred. We found no significant differences in gap formation force and yielding strength of the tendons between the two methods. The surgeon's previous experience in tendon repairs did not improve the consistency, reliability or tensile strength of the repairs. We conclude that if a strong peripheral suture is added, the modified Lim-Tsai repair has the same technical reliability and consistency as the Adelaide repair in term of ultimate loading strength in this test setup.

The purpose of this study is to determine how loss of sensation affect hand dexterity. In this study, digital nerve block anaesthesia was performed in different stages of timing for thumb, index and middle fingers of 12 volunteers. The Moberg pick-up test was conducted in the assessment of hand dexterity. Grip and pinch forces were also measured. Loss of thumb sensation had the greatest effect on dexterity, increasing average timing by at least 10.5 seconds (range 3.4 to 32.4). Loss of sensation to the index and middle fingers has a lesser impact, but decreased hand grip and chuck pinch forces (grip -25% or -33%, chuck pinch -31% or -32% depending on the timing of injections). We concluded that loss of thumb sensation has the greatest impact on hand dexterity. Index and middle finger sensory loss had less of an impact on hand dexterity but decreased grip and chuck pinch forces. Level of evidence: IV.

Background: Platelet-rich plasma (PRP) and autologous blood are commonly used therapies for lateral epicondylitis, but the evidence from randomized, placebo-controlled trials is conflicting. Thus, it is still unclear if patients benefit from these treatments., Questions/purposes: In the setting of a randomized, placebo-controlled trial, we compared PRP, autologous blood, and saline injections in the treatment of lateral epicondylitis with respect to: (1) VAS pain scores, and (2) functional outcomes (DASH score and grip strength) 1 year after treatment., Methods: We performed a parallel-group, randomized, controlled participant- and assessor-blinded study including adults with clinically diagnosed lateral epicondylitis. We defined lateral epicondylitis as pain in the lateral humeral epicondyle area exacerbated during resisted wrist extension and epicondyle compression. The participants were recruited from a secondary referral center, after not responding to initial nonoperative treatment. Patients with other concomitant upper-limb symptoms and surgical treatment of the elbow were excluded. Randomization sequence was generated with computer software and concealed from the investigators. We randomized 119 participants to receive an injection of PRP, autologous blood, or saline (1:1:1) in the proximal insertion of the extensor carpi radialis brevis muscle; 40 participants received PRP, 40 received autologous blood, and 39 received a saline injection. To prepare the PRP, we collected venous blood with a syringe kit followed by centrifugation, whereas autologous blood group received unprepared blood injection. Two unblinded investigators gave injections while the participant was unable to see the injection. There was no formal postinjection rehabilitation protocol and the use of NSAIDs was similar between different treatment arms. Follow-up visits were at 4, 8, 12, 26, and 52 weeks after the injection. The primary outcome measure was improvement in pain, measured with VAS scale (without specification as to whether the pain was activity related or at rest; range 0-10; a higher score indicates worse pain; the minimum clinically important difference [MCID] on the 10-cm scale was 1.5 cm), from baseline to 52 weeks. The secondary outcomes were the DASH score (range 0-100; a higher indicates a poorer outcome, and the MCID was 10.2 points) and grip strength. All patients were included in the analyses, and analyses were performed using the intention-to-treat principle. There was no crossover between treatment groups. At 52 weeks, nearly all (95% [38 of 40]) participants in autologous blood group were available for analysis whereas 78% (31 of 40) and 82% (32 of 39) were available in PRP and saline groups. This study was registered at ClinicalTrials.gov and funded by the local hospital district. With 40 patients in each group, we had 80% power to detect a clinically important improvement in pain (1.5 cm on the 10-cm VAS pain scale)., Results: There were no clinically important differences in the mean VAS pain or DASH scores among the groups at any timepoint. At 52 weeks, the mean difference in the VAS score for pain was -0.2 (95% CI -1.5 to 1.1; p = 0.75) for PRP versus saline and 0.5 (95% CI -0.7 to 1.7; p = 0.40) for autologous blood versus saline. The corresponding mean differences in the DASH score were 0.0 (95% CI -9.2 to 9.2; p > 0.99) and 7.7 (95% CI -1.3 to 16.7; p = 0.09) and those for grip strength were 1.4 kg (95% CI -3.3 to 6.1; p = 0.56) and -0.2 kg (95% CI -5.0 to 4.5; p = 0.92). No complications occurred because of the injections., Conclusions: PRP or autologous blood injections did not improve pain or function at 1 year of follow-up in people with lateral epicondylitis compared with those who were given a saline injection. However, because the 95% CIs did not exclude the MCID in VAS scores for autologous blood versus saline at 52 weeks, it is possible that a larger study could identify a between-group difference that we missed, but the effect size of that difference (based on our findings), even if present, is likely still to be small. Until or unless future randomized trials convincingly show a benefit either to PRP or autologous blood injections, we recommend against their use in patients with lateral epicondylitis., Level of Evidence: Level II, therapeutic study.

This study evaluates the long-term results of pollicization for a congenitally absent or severely hypoplastic thumb. Twenty-nine patients with 34 pollicizations were divided to two groups: those with simple thumb hypoplasia (22 pollicizations) and those with radial longitudinal dysplasia (12 pollicizations). The patients were followed from 1.3 to 32 years, with a mean follow-up time of 11 years. The patients were examined clinically and radiologically, and they completed a questionnaire concerning satisfaction with appearance, function, and social interaction. The Percival score was also calculated. In both groups, grip and pinch strengths of the operated hands were inferior to the normative age-related values. Radiologically, flattening of the original metacarpal head was found in 20 out of the 34 operated hands. We found better patient satisfaction in the simple hypoplasia group than in the radial longitudinal dysplasia group. The functional outcomes and patients' satisfaction did not correlate with the age of patients at operation. Level of evidence: IV.

Purpose: To investigate factors that cause variation in the mechanical properties of flexor tendon repairs., Methods: One surgeon repaired 50 homogeneous absorbent sticks and 40 porcine flexor tendons with a simple loop, an Adelaide repair, a peripheral over-and-over repair, or a combination of the latter 2 repairs. Ten hand surgeons repaired 1 porcine flexor tendon with the combined Adelaide core and over-and-over peripheral repair. We loaded the samples statically until failure and calculated the variations caused by the testing process, tendon substance, and surgical performance in terms of yield and ultimate load., Results: Tendon material and surgical performance both caused about half of the variation in the yield load of the combined repair. Surgical performance caused all variations observed in the ultimate load of the combined, peripheral-only, and core repairs. The effect of the tendon material was negligible in ultimate load. The intersurgeon variation was present only in yield load, and it represented one-tenth of the total variation., Conclusions: The effect of tendon substance on variation of the ultimate load is minimal. In yield load, both tendon and surgical performance are responsible for the variation., Clinical Relevance: In clinical realm, variation caused by testing is not present, but intersurgeon variation may cause additional variation in yield load. A hand surgeon cannot change the variation due to tendon properties, but with a more meticulous surgical technique, the variation related to the surgical performance can probably be diminished., (Copyright © 2018 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

Purpose: Substantial gap formation of a repaired finger flexor tendon is assumed to be harmful for tendon healing. The purpose of this study was to investigate the relationship between gap formation and the failure of the repair during cyclic loading., Methods: Thirty-five porcine flexor tendons were repaired and tested cyclically using variable forces until failure or a maximum of 500 cycles. Depending on the biomechanical behavior during cyclic testing, specimens were divided into 3 groups: Sustained (no failure), Fatigued (failure after 50 cycles), and Disrupted (failure before 50 cycles). The relationships between the gap formations, time-extension curves, and group assignments of the samples were investigated., Results: The time-extension curves of the Fatigued specimens showed a sudden onset of repair elongation-a fatigue point-which preluded the subsequent failure of the repair. This point coincides with the start of plastic deformation and, thereafter, cumulative injury of the repair consistently led to failure of the repair during subsequent cycles. None of the sustained repairs showed a fatigue point or substantial gapping during loading., Conclusions: We conclude that the emergence of a fatigue point and subsequent gap formation during loading will lead to failure of the repair if loading is continued., Clinical Relevance: The results of this experimental study imply that an inadequate flexor tendon repair that is susceptible to gap formation is under risk of failure., (Copyright © 2018 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

The aim of the present study was to investigate the incidence of scaphoid fracture surgery by obtaining data from the national discharge register in Finland, a country of 5 million inhabitants, for the period from 1997 to 2014. A total of 1380 patients with scaphoid fracture were treated surgically. Half of the patients were aged under 28 years and 84% were men. The surgical treatment of scaphoid fractures was classified into two groups. There were 640 (46%) primary fracture fixations and 740 (54%) treatments of fracture nonunion. The overall incidence of all scaphoid fixations increased twofold (from 14.8 to 30.1 per 1,000,000 person-years) and threefold in the primary fixation group (from 5.5 to 17.8 per 1,000,000 person-years) during the study period., Level of Evidence: III.

Introduction: Dupuytren's contracture (DC) is a chronic fibroproliferative disorder of the palmar fascia which leads to flexion contracture in one or more fingers. There is no definitive cure for DC, and treatment aims at relieving symptoms by releasing the contracture using percutaneous or operative techniques., Methods and Analysis: We planned a prospective, randomised, controlled, outcome assessor-blinded, three-armed parallel 1:1:1, multicentre trial comparing the effectiveness and cost of (1) collagenase clostridium histolyticum injection followed by limited fasciectomy in non-responsive cases, (2) percutaneous needle fasciotomy followed by limited fasciectomy in non-responsive cases and (3) primary limited fasciectomy during short-term and long-term follow-up for Tubiana I-III stages DC. We will recruit participants from seven national centres in Finland. Primary outcome is the rate of success in the treatment arm at 5 years after recruitment. Success is a composite outcome comprising (1) at least 50% contracture release from the date of recruitment and (2) participants in a patient-accepted symptom state (PASS). Secondary outcomes are (1) angle of contracture, (2) quick disabilities of the arm, a shoulder and hand outcome measure (QuickDASH), (3) perceived hand function, (4) EQ-5D-3L, (5) rate of major adverse events, (6) patient's trust of the treatment, (7) global rating, (8) rate of PASS, (9) rate of minimal clinically important improvement, (10) expenses, (11) progression of disease, (12) progression-free survival, (13) favoured treatment modality, (14) patients achieving full contracture release and >50% improvement and (15) patient satisfaction with the treatment effect. Predictive factors for achieving the PASS will also be analysed., Ethics and Dissemination: The protocol was approved by the Tampere University Hospital Institutional Review Board and Finnish Medicine Agency. The study will be performed according to the principles of good clinical practice. The results of the trial will be disseminated as published articles in peer-reviewed journals., Trial Registration Number: NCT03192020; Pre-results., Competing Interests: Competing interests: MPR, shoulder arthroscopy course paid for by Arthrex and nerve repair course paid for by Axone. TK, cadaver course paid for by Articular Finland and lecture fee from Summed., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Objective: The objectives of this survey were (1) to study if surgeons' perceptions of the benefit of six surgical procedures differ if they consider themselves as patients instead of treating a patient, (2) to evaluate the role of five predetermined factors that may influence decision-making, and (3) to assess how uniformly hand surgeons and hand therapists perceive the benefits of the surgical treatments., Methods: The members of the national societies for Hand Surgery and Hand Therapy were asked to participate in the survey. Six patient cases with hand complaint (carpal tunnel syndrome, flexor tendon injury, dorsal wrist ganglion, thumb amputation, boxer's fracture, and mallet fracture) and a proposed operative procedure were presented, and the respondents rated the procedures in terms of the expected benefit. Half of the surgeons were advised to consider themselves as patients when filling out the survey., Results: A survey was completed by 56 surgeons (61%) and 59 therapists (20%). Surgeons who considered themselves as patients had less confident perception on the benefit of carpal tunnel release compared with surgeons, who considered treating patients. Hand surgeons and hand therapists had similar perception of the benefits of surgery. The expected functional result was regarded as the most important factor in directing the decision about the treatment., Conclusions: Surgeons tended to be more unanimous in their opinions in cases, where there is limited evidence on treatment effect. The agreement between surgeons and therapists implies that the clinical perspectives are similar, and probably reflect the reality well.

Purpose: Clinically proven methods to prevent adhesion formation after flexor tendon repair have not yet been established. The aim of this pilot study was to assess the feasibility of amniotic membrane allograft as a mechanical barrier to decrease adhesion formation., Methods: Ten patients having flexor tendon injuries were planned to be recruited to the pilot study. The operative treatment consisted of tendon repair and fixation of amniotic membrane allograft around the repaired tendon. The primary outcome variable was the range of motion of the operated finger 6 months after the operation. Patients were monitored for infections and repair failures., Results: The study was terminated owing to unfavorable results after treatment of 5 patients. One patient had extensive stiffness and was subjected to tenolysis and joint release. Histopathological analysis of the tendon sheath revealed focal fibrosis. Another patient had a repair failure. The other 3 patients had fair to good results., Conclusions: It seems improbable that the use of amniotic membrane allograft would yield clinically relevant improvement compared with the existing techniques. However, it remains unclear whether the unfavorable results are associated with technical factors, amniotic membrane allograft itself, or an irregular distribution of complications., Type of Study/level of Evidence: Therapeutic V., (Copyright © 2017 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

Accidents with powered wood splitters cause a distinct group of hand injuries in which the injury spectrum ranges from a minor lesion to mutilating defects. We studied these injuries in order to assess the consequences and estimate the associated costs. A 2-year cohort of patients was retrospectively identified from medical records. The details of the injuries and the treatment were collected, and estimates of the resources used were based on hospital billing and the average costs of sick leave and disability. A total of 67 patients were identified and seven of those were children. Most patients sustained a major hand injury and an emergency microsurgical operation was indicated in 40% of patients. The total cost associated with the injuries was estimated at €3.33 million (£2.56 million, US$3.62 million). The treatment of this relatively small number of injuries demands substantial medical resources, and most of the costs are due to sick leave and disability. Level of evidence IV.

Coronal plane fracture of lunate in Kienböck disease is a challenging problem with no proven treatment. We present a technique for the treatment. A vascularized bone graft from the distal radius employing the fourth and fifth extracompartmental artery pedicles is used as a mechanical support in order to enable fracture union. The technical pearls and pitfalls are described and a clinical case is presented., (Copyright © 2016 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

The aim of this study was to find out how common it is to modify standard core suture configurations in flexor tendon repair and whether the use of standard core suture configurations gives a stronger repair. A total of 16 hand surgeons or residents participated in a workshop, in which they were asked to draw the suture configurations they used and to repair a porcine tendon. The properties of the repaired tendons were measured. Seven participants used a standard core suture configuration, and nine used a modified core suture. The biomechanical properties of the repairs were not affected by modifications to the core suture. However, they were affected by the number and lengths of peripheral suture bites, type of peripheral suture and the location of the core suture knot., (© The Author(s) 2016.)

To study the biomechanical properties of flexor tendon repairs, static tensile testing is commonly used because of its simplicity. However, cyclic testing resembles the physiological loading more closely. The aim of the present study is to assess how the biomechanical competence of repaired flexor tendons under cyclic testing relates to specific parameters derived from static tensile testing. Twenty repaired porcine flexor tendons were subjected to static tensile testing. Additional 35 specimens were tested cyclically with randomly assigned peak load for each specimen. Calculated risks of repair failure during repetitive loading were determined for mean of each statically derived parameter serving as a peak load. Furthermore, we developed a novel objective method to determine the critical load, which is a parameter predicting the survival of the repair in cyclic testing. The mean of statically derived yield load equalled the mean of critical load, justifying its role as a valid surrogate for critical load. However, regarding mean of any determined parameter as a clinically safe threshold is arbitrary due to the natural variation among samples. Until the universal performance of yield load is verified, we recommend employing cyclically derived critical load as primary parameter when comparing different methods of flexor tendon repair., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Objectives: A lesion in the spinal accessory nerve is typically iatrogenic: related to lymph node biopsy or excision. This injury may cause paralysis of the trapezius muscle and thus result in a characteristic group of symptoms and signs, including depression and winging of the scapula, drooped shoulder, reduced shoulder abduction, and pain. The elements evaluated in this long-term follow-up study include range of shoulder motion, pain, patients' satisfaction, delay of surgery, surgical procedure, occupational status, functional outcome, and other clinical findings., Methods: We reviewed the medical records of a consecutive 37 patients (11 men and 26 women) having surgery to correct spinal accessory nerve injury. Neurolysis was the procedure in 24 cases, direct nerve repair for 9 patients, and nerve grafting for 4. Time elapsed between the injury and the surgical operation ranged from 2 to 120 months. The patients were interviewed and clinically examined after an average of 10.2 years postoperatively., Results: The mean active range of movement of the shoulder improved at abduction 44° (43%) in neurolysis, 59° (71%) in direct nerve repair, and 30° (22%) in nerve-grafting patients. No or only slight atrophy of the trapezius muscle was observable in 75%, 44%, and 50%, and no or controllable pain was observable in 63%, 56%, and 50%. Restriction of shoulder abduction preceded deterioration of shoulder flexion. Patients' overall dissatisfaction with the state of their upper extremity was associated with pain, lower strength in shoulder movements, and occupational problems., Conclusion: We recommend avoiding unnecessary delay in the exploration of the spinal accessory nerve, if a neural lesion is suspected.

Introduction: The management of purulent flexor tenosynovitis of the hand consists of surgical debridement followed by antibiotic treatment. Usually, the debridement is carried out by irrigating the tendon sheath in a proximal to distal direction facilitated by two small incisions. It is unclear whether intraoperative irrigation by itself is adequate for healing or if it should be combined with postoperative irrigation in the ward. The hypothesis of this prospective randomised trial is that intraoperative catheter irrigation alone is as effective as a combination of intraoperative and postoperative intermittent catheter irrigation in the treatment of purulent flexor tenosynovitis., Methods and Analysis: In this investigator-blinded, prospective randomised trial, 48 patients suffering from purulent flexor tenosynovitis are randomised in two groups. Intraoperative catheter irrigation of the flexor tendon sheath and antibiotic treatment is identical in both groups, whereas only the patients in one group are subjected to intermittent postoperative catheter irrigation three times a day for 3 days. The primary outcome measure is total active range of movement of the affected finger after 3 months of surgery. The secondary outcome is the need for reoperation., Ethics and Dissemination: The research ethics committee of Pirkanmaa Hospital District has approved the study protocol. The protocol has been registered with ClinicalTrials.gov registry (#NCT02320929). All participants will give written informed consent. The study results will elucidate the role of postoperative irrigation, which can be criticised as being labour consuming and unpleasant to the patient. The results of the study will be disseminated as a published article in a peer-reviewed journal., Trial Registration Number: NCT02320929; pre-results., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/)

In a previous study we found that the strength of a Kessler core suture in the flexor tendon was greater in flexor zone 2 than in zone 3. To further investigate the material properties of the flexor tendon without the influence of a locking suture configuration, we measured the ultimate strength of a simple loop suture in the flexor digitorum profundus tendon in zones 1, 2, and 3. Eight cadaver flexor digitorum profundus tendons were tested in 10 mm increments with a 3-0 polyester suture loop pull-out test in the mid-substance of the tendon. The mean strength in zones 1 and 2 (26.7 N, SD 5.6) was significantly higher than the mean strength in zone 3 (17.7 N, SD 5.4). We conclude that the difference is owing to variations of the structure of the flexor tendon in different sections of the tendon, as the suture configuration was a simple loop without a locking or grasping component.

Bone dynamically adapts its structure to the environmental demands placed upon it. Load-related stimuli play an important role in this adaptation. It has been postulated that osteocytes sense changes in these stimuli and initiate adaptive responses, across a number of scales, through a process known as mechanotransduction. While much research has focused on gross and tissue-level adaptation, relatively little is known regarding the relation between cellular-level features (e.g. osteocyte lacunar density, volume and shape) and loading. The increasing availability of high resolution 3D imaging modalities, including synchrotron-based techniques, has made studying 3D cellular-level features feasible on a scale not previously possible. The primary objective of this study was to test the hypothesis that unloading (sciatic neurectomy) during growth results in altered osteocyte lacunar density in the tibial diaphysis of the rat. Secondarily, we explored a potential effect of unloading on mean lacunar volume. Lacunar density was significantly (p<0.05) lower in immobilized bones (49,642 ± 11,955 lacunae per mm(3); n=6) than in control bones (63,138 ± 1956 lacunae per mm(3); n=6). Mean lacunar volume for immobilized bones (209 ± 72 μm(3); n=6) was significantly smaller (p<0.05) than that for the control bones (284 ± 28 μm(3); n=6). Our results demonstrate that extreme differences in loading conditions, such as those created by paralysis, do indeed result in changes in osteocyte lacunar density and volume. Further investigation is warranted to examine relations between these measures and more subtle variation in loading as well as pathological states, which have been linked to alterations in mechanotransduction., (Copyright © 2012 Elsevier Inc. All rights reserved.)

It is well established that bone is capable of adapting to changes in loading; however, little is known regarding how loading specifically affects the internal 3D microarchitecture of cortical bone. The aim of this study was to experimentally test the hypothesis that loading is a determinant of the 3D orientation of primary vascular canals in the rat tibial diaphysis. Left tibiae from 10 rats (30 weeks old) that had been immobilized (sciatic neurectomy) for 27 weeks, right SHAM-operated tibiae from these same rats (internal control) and right tibiae from 10 normal age-matched rats (external control) were scanned by micro-CT. Mean canal orientation (for the whole bone segment and by region), percent porosity, canal diameter and canal separation were quantitatively assessed in 3D. Canal orientation in the immobilized tibiae was significantly (P < 0.001) more radial (by 9.9°) compared to the external controls but did not differ from the internal controls (P = 0.310). Comparing the external and internal controls, orientation was significantly (P < 0.05) more radial in the internal control group (by 6.8°). No differences were found for percent porosity and canal separation. Canal diameter was significantly greater in the immobilized vs. internal (P < 0.001) and external control (P < 0.001) tibiae. The differences in orientation relative to the external controls indicated that the organization of cortical bone in the rat is affected by loading. Although the predicted difference in canal orientation was not detected between immobilized and internal control groups, the distributions of individual canal orientations, from which the mean values were derived, revealed distinctive patterns for all three groups. The internal controls exhibited an intermediate position between the immobilized and external controls, suggesting that paralysis on the contralateral side resulted in altered loading relative to the normal state represented by the external control. This was also evident in a regional analysis by quadrant. The loaded bones had the same cross-sectional shape; however, their internal structure differed. These results provide novel insights into the impact of loading on the 3D organization of primary cortical bone and have implications for understanding the relation between cortical bone adaptation, disease and mechanical properties., (© 2011 The Authors. Journal of Anatomy © 2011 Anatomical Society of Great Britain and Ireland.)

This study compared the biomechanical behaviour of repairs in the human flexor digitorum profundus tendon in zones I, II and III with repairs of different segments of the porcine flexor tendon of the second digit and the extensor digiti quarti proprius tendon, in order to assess the validity of porcine tendons as models for human flexor tendon repairs. These porcine tendons were selected after comparing their size with the human flexor digitorum profundus tendon. The tendon repairs were done in three segments of each porcine tendon and repairs in the human tendons were done in zones I,II and III. Ten tendons in each group yielded a total of 90 specimens. A modified Kessler repair was done with 3-0 coated braided polyester suture and subjected to uniaxial tensile testing. In human flexor tendons, the ultimate force was higher in zones I and II than in zone III. The porcine flexor digitorum profundus tendon from the second digit and the proximal segment of the extensor digiti quarti proprius tendon behaved similarly to the human flexor tendon in zone III and can be considered as surrogates for the human flexor tendon.

Although micro-computed tomography (micro-CT) has become the gold standard for assessing the 3D structure of trabecular bone, its extension to cortical bone microstructure has been relatively limited. Desktop micro-CT has been employed to assess cortical bone porosity of humans, whereas that of smaller animals, such as mice and rats, has thus far only been imaged using synchrotron-based micro-CT. The goal of this study was to determine if it is possible to visualize and quantify rat cortical porosity using desktop micro-CT. Tibiae (n = 10) from 30-week-old female Sprague-Dawley rats were imaged with micro-CT (3 μm nominal resolution) and sequential ground sections were then prepared. Bland-Altman plots were constructed to compare per cent porosity and mean canal diameter from micro-CT (3D) versus histology (2D). The mean difference or bias (histology-micro-CT; ±95% confidence interval) for per cent porosity was found to be -0.15% (±2.57%), which was not significantly different from zero (P= 0.720). Canal diameter had a bias (±95% confidence interval) of -5.73 μm (±4.02 μm) which was found to be significantly different from zero (P < 0.001). The results indicated that cortical porosity in rat bone can indeed be visualized by desktop micro-CT. Quantitative assessment of per cent porosity provided unbiased results, whereas direct analysis of mean canal diameter was overestimated by micro-CT. Thus, although higher resolution, such as that available from synchrotron micro-CT, may ultimately be required for precise geometric measurements, desktop micro-CT--which is far more accessible--is capable of yielding comparable measures of porosity and holds great promise for assessment of the 3D arrangement of cortical porosity in the rat., (© 2010 The Authors Journal compilation © 2010 The Royal Microscopical Society.)

This study evaluated the contributions of locomotive loading and estrogen to the development of diaphysis of rat femur. A randomized 2x2 study design was used. Altogether, 70 female Sprague-Dawley rats were used, of which 10 were euthanized at entry. Of the remaining rats, 16 served as controls, and the rest, 44, underwent a unilateral sciatic neurectomy. The effect of estrogen was removed by ovariectomizing one-half of the neurectomized rats. After 27 wk, the animals were euthanized, and the femora were excised. Irrespective of loading or estrogen, the femur length and mineral mass increased by 142 and 687%, respectively. Axial growth was not modulated either by locomotive loading or estrogen, but the loading resulted in direction-specific changes in the cross-sectional geometry. The estrogen-related gains were evident on the endocortical surface, while the loading-related gains occurred on the periosteal surface. The loading and estrogen were significantly associated with increased bone strength (21 and 15%, respectively) in the mediolateral direction, but not in the anteroposterior direction. Axial growth and accrual of bone mineral mass of the rat femur are largely independent of locomotive loading or estrogen, whereas these factors specifically account for the femur function, as either a mechanical lever or a mineral reservoir for reproduction, respectively.

Background: According to prevailing understanding, skeletal mechano-responsiveness declines with age and this apparent failure of the mechano-sensory feedback system has been attributed to the gradual bone loss with aging (age-related osteoporosis). The objective of this study was to evaluate whether the capacity of senescent skeleton to respond to increased loading is indeed reduced as compared to young mature skeleton., Methods and Findings: 108 male and 101 female rats were randomly assigned into Exercise and Control groups. Exercise groups were subjected to treadmill training either at peak bone mass between 47-61 weeks of age (Mature) or at senescence between 75-102 weeks of age (Senescent). After the training intervention, femoral necks and diaphysis were evaluated with peripheral quantitative computed tomography (pQCT) and mechanical testing; the proximal tibia was assessed with microcomputed tomography (microCT). The microCT analysis revealed that the senescent bone tissue was structurally deteriorated compared to the mature bone tissue, confirming the existence of age-related osteoporosis. As regards the mechano-responsiveness, the used loading resulted in only marginal increases in the bones of the mature animals, while significant exercise-induced increases were observed virtually in all bone traits among the senescent rats., Conclusion: The bones of senescent rats displayed a clear ability to respond to an exercise regimen that failed to initiate an adaptive response in mature animals. Thus, our observations suggest that the pathogenesis of age-related osteoporosis is not attributable to impaired mechano-responsiveness of aging skeleton. It also seems that strengthening of even senescent bones is possible--naturally provided that safe and efficient training methods can be developed for the oldest old.

Total variation in any measured variable, in conjunction with expected treatment effect, defines the minimum sample size (minSS) required to detect the expected effect with statistical confidence should the effect truly exist. A comprehensive literature survey of 3472 original studies was carried out to identify studies with biomechanical testing of whole bones. Total variation in common biomechanical traits and expected treatment effects in typical interventions were statistically determined. According to this survey, total variation in biomechanical traits between different species of experimental animals was similar, justifying the use of rat femur as a model in further analyses. Due to poorer precision, stiffness and energy absorption assessment require substantially larger sample size than breaking load. Due to same reason, minSS for femoral neck compression test is considerably larger than for femoral shaft three-point bending test. For the bending test, minSS to show a 10% treatment effect in the breaking load with 80% statistical power is 11rats/group, while corresponding minSS is 23 for the stiffness, and 53 for the energy absorption. For the femoral neck compression test, minSSs are 16, 51, and 134rats/group, respectively. Among the reviewed studies, the mean sample size was 11animals/group. This underscores the need for considerably larger sample sizes in experimental bone interventions which employ mechanical traits as primary outcome variables. In particular, poor precision and generally small expected treatment effects compromise the utility of stiffness and energy absorption assessments in experimental bone interventions.