Efficacy of collagen conduit wrapping with collagen fibers on nerve regeneration in sciatic nerve injury with partial transection: An experimental study in the rat model.

Peripheral nerve injuries (PNIs) include complete and partial transection, crushing, and chronic compression injuries. Hollow absorbable conduits are used to treat complete transection with short defects, while wrapping the injured part with an absorbent material promotes nerve recovery by inhibiting inflammatory cell infiltration and scar tissue formation in crush injuries. For treatment of partially transected nerve injuries (PTNIs), such as injection-related iatrogenic PNI, whether wrapping the entire nerve, including the injury site, or bridging the transected fascicle with an artificial nerve conduit (ANC) is beneficial remains to be verified. The purpose of this study was to investigate whether wrapping the injured nerve and placing collagen fibers as scaffolds at the nerve defect site contribute to neural recovery in PTNI. A unilateral 5-mm partial nerve defect was created at the mid-thigh level in a rat sciatic nerve injury model. Fifty-four Sprague-Dawley (SD) rats (150-250 g) were divided into three groups (n = 9 each): group 1, collagen fibers were placed in the nerve defect and the sciatic nerve was wrapped with collagen conduit; group 2, the sciatic nerve was wrapped by collagen conduit without collagen fibers; and group 3, nerve defect was reconstructed with collagen-filled conduit. Nerve regeneration was evaluated by analyses of gait, electrophysiology, wet muscle weight, and axon numbers with immunohistochemistry at 12 and 24 weeks. Dorsiflexion angles among all groups improved significantly from 12 to 24 weeks postoperatively. At 24 weeks postoperatively, compound muscle action potential amplitudes (CMAPs) of tibialis anterior were 5.26 ± 4.64, 1.31 ± 1.17, and 0.14 ± 0.24 mV (p < .05), CMAPs of gastrocnemius were 21.3 ± 5.98, 15.4 ± 5.46, and 13.11 ± 3.91 mV in groups 1, 2, and 3, respectively; and the value of group 1 was significantly higher than that of group 3 (p < .05). Axon numbers were 2194 ± 629; 1106 ± 645; and 805 ± 907 in groups 1, 2, and 3, respectively (p < .05). For PTNI reconstruction, artificial nerve wrap (ANW) was superior to ANC. Providing collagen scaffold at the nerve defect site enhanced nerve recovery during reconstruction with ANW.

Limiting Levels of Fingertip Replantation Without Venous Anastomosis.

PURPOSE: This study aimed to compare the success rates of fingertip replantation with and without venous anastomosis. METHODS: This retrospective study included 132 patients with 148 fingertip injuries who had undergone fingertip replantation (Ishikawa's classification I‒IV) between 2003 and 2020 at our hospital. Among them, 117 and 15 were men and women respectively, and their mean age was 43 years. There were 53, 44, and 51 fingertips with Ishikawa subzone II, III, and IV amputations respectively, and no cases were classified as Ishikawa subzone I. Venous anastomosis was performed on 64 fingertips (group A). This was not possible in the remaining 84 fingertips; thus, an external bleeding method was used (group B). Our external bleeding protocol consisted of 4-hourly skin pricks of the distal pulp with a 23-gauge needle for the first 5 days. The analyses included survival rates, hemoglobin levels (Hb), and blood transfusions administered. RESULTS: The overall survival rate was 90.5% (134 of 148). In group A, survival was achieved in 92.3%, 100%, and 94.3% of those with subzones II, III, and IV amputations, respectively. In group B, survival was achieved in 100%, 82.1%, and 62.5% of those with subzones II, III, and IV, respectively. Subzone IV in group B showed a significantly lower rate of replantation success. In groups A and B, the preoperative and 7-day postoperative Hb levels were 14.5 g/dL and 14.6 g/dL, and 11.3 g/dL, and 11.6 g/dL, respectively. In addition, blood transfusion was required for five patients (7.9%) in group A and six patients (7.9%) in group B. Thus, the Hb levels and blood transfusion administered were similar between the two groups. CONCLUSIONS: Subzone IV is an important threshold for artery-only replantation. Furthermore, our external bleeding protocol is a safe and effective method. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Mid-term outcomes of digital nerve injuries treated with Renerve® synthetic collagen nerve conduits: A retrospective single-center study.

BACKGROUND: Biodegradable synthetic nerve conduits have become widely used for peripheral nerve injuries. Recently, bioabsorbable collagen conduits filled with collagen fibers (Renerve®) are commercially available in Japan. We investigated the clinical efficacy and safety of Renerve® conduits for digital nerve repair. PATIENTS AND METHODS: We retrospectively reviewed data of patients who underwent digital nerve repair using Renerve® conduits between August 2017 and February 2022 at our hospital and were followed up for at least 12 months. Seventeen patients (20 nerves) with a median age of 46.5 years (interquartile rage: 26-48 years) were included in the analysis. We analyzed sensory nerve function recovery and residual pain or uncomfortable tingling, as well as safety outcomes. The relationship between nerve defect length and sensory function data was assessed using Spearman's rank correlation. RESULTS: Sensory nerve function at 12 months postoperatively was excellent in six, good in 10, and poor in four nerves, and that at the final follow-up (median period, 24 months; range, 12-30 months) was excellent in nine, good in 10, and poor in one nerve. All nerves with a defect length of <12 mm had excellent or good sensory outcomes. At 12 months postoperatively, the correlation coefficients between nerve defect length and Semmes-Weinstein monofilament test results, static two-point discrimination, and dynamic two-point discrimination were 0.35 (p = 0.131), 0.397 (p = 0.0827), and 0.451 (p = 0.0461), respectively. Residual pain or tingling sensation were observed in four nerves at the final follow-up. No postoperative complications were observed in any of the patients. CONCLUSIONS: This study demonstrated the clinical efficacy and safety of Renerve® conduits for digital nerve repair. Our results will be useful in clinical practice because of the scarcity of real-world data on the use of Renerve® conduits for digital nerve repair.

Do triangular fibrocartilage complex foveal injuries affect the clinical outcome of ulnar shortening osteotomy for ulnar impaction syndrome?

BACKGROUND: Ulnar shortening osteotomy (USO), as its name implies, is used to shorten the ulna. It subsequently tightens the triangular fibrocartilage complex (TFCC) and ulnar wrist. TFCC foveal insertion is a primary stabilizer of the distal radioulnar joint. It is unclear whether USO is effective in TFCC foveal injuries. The purpose of this study was to review the clinical outcomes of ulnar shortening osteotomies with and without TFCC foveal injuries. METHODS: We retrospectively reviewed patients with ulnar wrist pain treated with USO and wrist arthroscopy including the distal radioulnar joint (DRUJ). Sixty-five patients were included in this study. An algorithm was used to guide surgical decision-making. After arthroscopic confirmation of ulnar impaction syndrome, we performed USO with a locking compression plate (mean length of shortening, 2.7 mm; range, 1-7.5 mm). The flattened TFCC disc due to ulnar shortening was confirmed arthroscopically. If the DRUJ was unstable after USO, we repaired the TFCC foveal insertion. RESULTS: There were 32 post-traumatic and 33 idiopathic cases. We detected TFCC disc injuries in 34 wrists and TFCC foveal injuries in 33 wrists; both types were found in 15 wrists. TFCC foveal injuries were not significantly correlated with patient age, history of trauma, or clinical outcome. Most patients showed good clinical outcomes; 31 of 65 patients had preoperative DRUJ instability, with a significant number having foveal but not disc injuries. CONCLUSION: USO achieved reasonable outcomes, even in patients with TFCC foveal injuries. In cases demonstrating ulnar impaction, USO should be prioritized over TFCC repair.

Mast cell presence in tendon sheaths of trigger fingers: implications on pathogenesis and clinical presentation.

Trigger finger is a common hand disorder; however, its pathogenesis remains unknown. In this study, we aimed to investigate mast cells, fibroblast activators that synthesize collagen, in the tendon sheaths of trigger fingers. We investigated the presence of mast cells and their association with changes in the collagen content of the tendon sheath and clinical data. We performed a multicenter prospective study of 77 adult patients with trigger finger who had undergone resection of the first annular pulley between August 2012 and January 2020. The tendon sheath was immunostained with an anti-tryptase antibody to confirm mast cell presence. The percentage of collagen in the tendon sheath was determined by picrosirius red staining observed through a polarization microscope. The clinical data, including the duration from symptom onset to surgery, severity, pain numerical rating scale, and Hand20 scores, were evaluated. Tryptase-positive mast cells were recognized in 83.5% of all specimens. The mast cell presence group (Group P) had a significantly higher percentage of type-3 collagen in the tendon sheath than the non-mast cell presence group (Group N) (Group P, 15.6%; Group N, 12.7%; p = 0.03). Moreover, Group P had significantly higher pain numerical rating scale (Group P; 5, Group N; 3, p = 0.04) and Hand20 (Group P; 35.5, Group N; 13.0, p = 0.01) scores than Group N. These findings suggest that mast cell presence in the tendon sheath of the trigger finger is related to the pathology and clinical symptoms of trigger finger.

A Wirelessly Powered 4-Channel Neurostimulator for Reconstructing Walking Trajectory.

A wirelessly powered four-channel neurostimulator was developed for applying selective Functional Electrical Stimulation (FES) to four peripheral nerves to control the ankle and knee joints of a rat. The power of the neurostimulator was wirelessly supplied from a transmitter device, and the four nerves were connected to the receiver device, which controlled the ankle and knee joints in the rat. The receiver device had functions to detect the frequency of the transmitter signal from the transmitter coil. The stimulation site of the nerves was selected according to the frequency of the transmitter signal. The rat toe position was controlled by changing the angles of the ankle and knee joints. The joint angles were controlled by the stimulation current applied to each nerve independently. The stimulation currents were adjusted by the Proportional Integral Differential (PID) and feed-forward control method through a visual feedback control system, and the walking trajectory of a rat's hind leg was reconstructed. This study contributes to controlling the multiple joints of a leg and reconstructing functional motions such as walking using the robotic control technology.

A Therapeutic Strategy for Lower Motor Neuron Disease and Injury Integrating Neural Stem Cell Transplantation and Functional Electrical Stimulation in a Rat Model.

Promising treatments for upper motor neuron disease are emerging in which motor function is restored by brain-computer interfaces and functional electrical stimulation. At present, such technologies and procedures are not applicable to lower motor neuron disease. We propose a novel therapeutic strategy for lower motor neuron disease and injury integrating neural stem cell transplantation with our new functional electrical stimulation control system. In a rat sciatic nerve transection model, we transplanted embryonic spinal neural stem cells into the distal stump of the peripheral nerve to reinnervate denervated muscle, and subsequently demonstrated that highly responsive limb movement similar to that of a healthy limb could be attained with a wirelessly powered two-channel neurostimulator that we developed. This unique technology, which can reinnervate and precisely move previously denervated muscles that were unresponsive to electrical stimulation, contributes to improving the condition of patients suffering from intractable diseases of paralysis and traumatic injury.

Functional Reconstruction of Denervated Muscle by Xenotransplantation of Neural Cells from Porcine to Rat.

Neural cell transplantation targeting peripheral nerves is a potential treatment regime for denervated muscle atrophy. This study aimed to develop a new therapeutic technique for intractable muscle atrophy by the xenotransplantation of neural stem cells derived from pig fetuses into peripheral nerves. In this study, we created a denervation model using neurotomy in nude rats and transplanted pig-fetus-derived neural stem cells into the cut nerve stump. Three months after transplantation, the survival of neural cells, the number and area of regenerated axons, and the degree of functional recovery by electrical stimulation of peripheral nerves were compared among the gestational ages (E 22, E 27, E 45) of the pigs. Transplanted neural cells were engrafted at all ages. Functional recovery by electric stimulation was observed at age E 22 and E 27. This study shows that the xenotransplantation of fetal porcine neural stem cells can restore denervated muscle function. When combined with medical engineering, this technology can help in developing a new therapy for paralysis.

Postoperative magnetic resonance imaging following lunate resection and vascularized os pisiform transfer in Kienböck's disease.

Although good clinical results have been reported following lunate resection and vascularized os pisiform transfer for advanced stages of Kienböck's disease, the occurrence of wrist osteoarthritis has been highlighted. We aimed to investigate the postoperative condition of the pisiform and the surrounding bones in patients who underwent surgery for advanced stages of Kienböck's disease using magnetic resonance imaging. We retrospectively reviewed the data of six patients (mean age, 45 years; Lichtman stage, IIIb) who underwent lunate resection and vascularized os pisiform transfer for advanced stages of Kienböck's disease and postoperative magnetic resonance imaging examination. We extracted clinical data on pre- and postoperative range of motion, grip strength, wrist pain, Hand20 and Lichtman's criteria, and pre- and postoperative radiographic and magnetic resonance imaging examinations. Bone marrow lesions in the transferred pisiform were found in five patients. Signal changes of bones around the transferred pisiform were found in these five patients; the greatest change was observed in the capitate bone in three patients. These signal changes were found in the opposite parts of the bones around the transferred pisiform. No patient exhibited signal changes in the transferred pisiform bone only. Wrist osteoarthritis after lunate resection and vascularized os pisiform transfer for advanced stages of Kienböck's disease is more likely to be attributed to the low congruency of the transferred pisiform and surrounding bones than to the compromised perfusion of the pisiform. Signal changes in the opposite bone parts around the transferred pisiform were confirmed in all patients with signal changes in the pisiform.

Postoperative peripheral neuropathy considered to be induced by surgical stress.

BACKGROUND: Most surgeons are unaware that idiopathic neuropathy, which occurs independently of mechanical injury, can present as postoperative peripheral neuropathy. The aim of this study was to reveal the presence of postoperative neuropathy considered to be induced by surgical stress and to make surgeons aware that idiopathic neuropathy can occur postoperatively. METHODS: We conducted a survey among orthopedic surgeons regarding patients with postoperative neuropathies of unknown cause. For each case, the type of neuropathy, preceding surgery and anesthesia, patient background, clinical findings, and clinical course were investigated. RESULTS: Seven patients were identified. The mean time from surgery to the onset of neuropathy was 9.3 days (range 1-15 days). Five of the patients fully recovered spontaneously within 1 year, while the remaining two underwent neurolysis. One patient presented with hourglass-like constrictions in the radial nerve. No inflammatory cells were found in the epineurium of the affected nerve. CONCLUSIONS: Although it is rare, postoperative idiopathic neuropathy occurs in clinical practice, and it is crucial that surgeons recognize the existence of this neuropathy to elucidate its pathogenesis as well as to reduce the risk of litigation.

Volar plating versus external fixation for unstable dorsal fracture-dislocations of the proximal interphalangeal joint.

We retrospectively compared the results of volar plating and dynamic external fixation for acute unstable dorsal fracture-dislocations of the proximal interphalangeal joint with a depressed fragment. We treated 31 patients (31 fingers), 12 with volar buttress plating and 19 with dynamic external fixation. Follow-up averaged 35 and 40 months in the two groups, with a minimal 6-month follow-up. Average active flexion of the proximal interphalangeal joint was 95° after plate fixation and 87° after external fixation, with an active extension lag of -6° and -9°, respectively. Active flexion at the distal interphalangeal joint averaged 67° in the plate group and 58° in the external fixation group, with active extension lags of 0° and -5°, respectively. We conclude that both methods can obtain a good range of motion at the proximal interphalangeal joint. A limitation of the extension of the distal interphalangeal joint occurred with dynamic external fixation but not with volar buttress plating.Level of evidence: IV.

Radial Osteotomy for Kienböck Disease: Clinical and Radiological Comparison between Younger and Older Patients.

Background: The usefulness of radial osteotomy for older patients remains unclear. The purpose of this study was to compare the clinical and radiological outcomes of radial osteotomy with volar locking plate between younger and older patients with Kienböck disease stages II to IIIB. Methods: This was a retrospective comparative study of 21 consecutive patients treated at our department. Lichtman's classification was used for staging, and four patients had stage II, six patients had stage IIIA, and 11 patients had stage IIIB disease. We divided them into two groups to compare the radiological and clinical results between younger (younger than 40 years) and older patients. The mean follow-up periods in the younger and older groups were 4 and 3.6 years, respectively. For radiological assessment, we evaluated the carpal height ratio (CHR), Stahl index, and union of the fractured lunate. For clinical assessment, we examined the range of motion of the wrist, grip strength, numeric rating scale (NRS) for pain, and the patient-reported Hand20 score preoperatively and at the final follow-up. Results: There were 12 patients in the younger group with a mean age of 23 years (range, 12-37 years), and 9 in the older group with a mean age of 56 years (range, 40-74 years). There were no intra- and post-operative complications in either group. Radiological improvement, including CHR, Stahl index, and union of the fractured lunate, was more common in the younger group than in the older one, as was the case for clinical improvement. However, even in the older group, significant clinical improvement, including the range of motion of the wrist, NRS for pain, and the Hand20 score, was seen postoperatively. Conclusions: Radial osteotomy appears to be a safe and reliable option in older symptomatic patients with Kienböck disease stages II to IIIB.

Choice of control group treatments in hand osteoarthritis trials: A systematic review and meta-analysis.

OBJECTIVES: To assess how patient characteristics and study design influence the effectiveness of control interventions in hand OA trials. METHODS: The study protocol was registered in PROSPERO (CRD42020163473). Two authors independently searched four electronic databases from their inception to December 31, 2019. Randomized and non-randomized controlled hand OA trials were included if pain intensity was assessed using a validated scale. We allocated control groups into one of the following: placebo, add-on treatment, no treatment, or active treatment. The standardized mean differences (d) of pain, as well as subjective function and hand strength, were pooled with 95% confidence intervals (CI) and 90% prediction intervals using random-effects models. Meta-regression and post-hoc subgroup analyses were performed to investigate which factors potentially impacted placebo analgesia and between-study heterogeneity. RESULTS: Thirty-one placebo, 11 add-on, 12 no-treatment, and 10 active-treatment controls were included in meta-analyses. Effective pain relief was observed in placebo (d = -0.50, 95% CI -0.63 to -0.37), add-on (d = -0.35, 95% CI -0.59 to -0.12), and active-treatment (d = -0.92, 95% CI -1.35 to -0.48) groups. In subjective function, these treatments had smaller but beneficial effects; hand strength, contrastingly, was not improved. Placebo effects were larger when flare designs were used (d = -0.96) and more homogeneous when minimum pain thresholds were set (d = -0.46, 90% prediction intervals -0.79 to -0.14). CONCLUSION: Placebo, add-on, and active control treatments were more effective than the no treatment control in relieving hand pain and improving subjective function. By choosing minimum pain thresholds and flare requirements at patient enrollment, moderate pain relief may be replicated among control participants in future randomized placebo-controlled trials.

Optimal conditions for graft survival and reinnervation of denervated muscles after embryonic motoneuron transplantation into peripheral nerves undergoing Wallerian degeneration.

Motoneuron transplantation into peripheral nerves undergoing Wallerian degeneration may have applications in treating diseases causing muscle paralysis. We investigated whether functional reinnervation of denervated muscle could be achieved by early or delayed transplantation after denervation. Adult rats were assigned to six groups with increasing denervation periods (0, 1, 4, 8, 12, and 24 weeks) before inoculation with culture medium containing (transplantation group) or lacking (surgical control group) dissociated embryonic motoneurons into the peroneal nerve. Electrophysiological and tissue analyses were performed 3 months after transplantation. Reinnervation of denervated muscles significantly increased relative muscle weight in the transplantation group compared with the surgical control group for denervation periods of 1 week (0.042% ± 0.0031% vs. 0.032% ± 0.0020%, respectively; p = 0.009), 4 weeks (0.044% ± 0.0069% vs. 0.026% ± 0.0045%, respectively; p = 0.0023), and 8 weeks (0.044% ± 0.0029% vs. 0.026% ± 0.0008%, respectively; p = 0.0023). The ratios of reinnervated muscle contractile forces to naïve muscle in the 0, 1, 4, 8, and 12 weeks transplantation groups were 3.79%, 18.99%, 8.05%, 6.30%, and 5.80%, respectively, indicating that these forces were sufficient for walking. The optimal implantation time for transplantation of motoneurons into the peripheral nerve was 1 week after nerve transection. However, the neurons transplanted 24 weeks after denervation survived and regenerated axons. These results indicated that there is time for preparing cells for transplantation in regenerative medicine and suggested that our method may be useful for paralysed muscles that are not expected to recover with current treatment.

Innervation of Meissner's corpuscles and Merkel -cells by transplantation of embryonic dorsal root ganglion cells after peripheral nerve section in rats.

Transplantation of embryonic motor neurons has been shown to improve motor neuron survival and innervation of neuromuscular junctions in peripheral nerves. However, there have been no reports regarding transplantation of sensory neurons and innervation of sensory receptors. Therefore, we hypothesized that the transplantation of embryonic sensory neurons may improve sensory neurons in the skin and innervate Merkel cells and Meissner's corpuscles. We obtained sensory neurons from dorsal root ganglia of 14-day rat embryos. We generated a rat model of Wallerian-degeneration by performing sciatic nerve transection and waiting for one week after. Six months after cell transplantation, we performed histological and electrophysiological examinations in naïve control, surgical control, and cell transplantation groups. The number of nerve fibers in the papillary dermis and epidermal-dermal interface was significantly greater in the cell transplantation than in the surgical control group. The percent of Merkel cells with nerve terminals, as well as the average number of Meissner corpuscles with nerve terminals, were higher in the cell transplantation than in the surgical control group, but differences were not significant between the two groups. Moreover, the amplitude and latency of sensory conduction velocity were evoked in rats of the cell transplantation group. We demonstrated that the transplantation of embryonic dorsal root ganglion cells improved sensory nerve fiber number and innervation of Merkel cells and Meissner's corpuscles in peripheral nerves.

Osteoid osteoma of the wrist misdiagnosed as de Quervain's tenosynovitis due to normal X-ray at the first visit: A case report.

INTRODUCTION: Osteoid osteomas are benign bone tumors that can occur in various bones throughout the body but are mainly found in the long bones. PRESENTATION OF THE CASE: We report the case of a patient who had been treated for more than three years for a case of de Quervain's tenosynovitis due to tenderness in the first compartment of the right wrist joint. An X-ray on his first visit to a clinic was normal, but it was eventually discovered that he had an osteoid osteoma of the wrist. DISCUSSION: The age of onset and gender proclivity of each disease should be considered. An X-ray should be taken in cases such as this, even to diagnose tendonitis. When any symptom, such as pain, has lingered for a long time and resisted treatment, we must reconsider the diagnosis. In patients with a low risk of tendonitis, it is essential to consider the possibility of other diseases if there is no improvement after treatment. As this patient's tumor was missed on the initial X-ray, it grew to a mature case of osteoid osteoma in three years. CONCLUSION: We experienced a very educational case of osteoid osteoma of the wrist misdiagnosed as de Quervain's tenosynovitis.

Compatibility of magnetic resonance imaging in patients with orthopedic implants: manufacturer questionnaires.

In clinical practice, surgeons have stated that magnetic resonance imaging (MRI) can be performed in patients with titanium alloy implants. However, manufacturers and distributors of many implants may not comply with this common practice. As such, this study aimed to investigate manufacturers' views on MRI use in patients fitted with their implants. The questionnaire survey was conducted between May and August 2018. Is your product compatible with MRI? ( ) Select from (1) to (3). In case of (1) or (2), up to ( ) Tesla. (1) MRI can be performed even at the sites of implanted fixators. (2) MRI can be performed at sites without implanted fixators. (3) MRI cannot be performed, or the manufacturer does not approve MRI use (cannot issue a certificate). The questionnaire forms were sent to 12 manufacturers, and the response rate was 100%. Manufacturers responded that they could not publicly allow MRI use in patients with their products. These findings do not conclude that MRI cannot be performed in such patients. This survey revealed that currently decisions regarding MRI use is left to the treating physicians. This situation poses a great problem for medical safety and imposes a substantial burden on physicians. As many problems remain in the field of orthopedic surgery, manufacturers of implants should proactively manage issues surrounding the usage of MRI.

Visual Feedback Control of a Rat Ankle Angle Using a Wirelessly Powered Two-Channel Neurostimulator.

Peripheral nerve disconnections cause severe muscle atrophy and consequently, paralysis of limbs. Reinnervation of denervated muscle by transplanting motor neurons and applying Functional Electrical Stimulation (FES) onto peripheral nerves is an important procedure for preventing irreversible degeneration of muscle tissues. After the reinnervation of denervated muscles, multiple peripheral nerves should be stimulated independently to control joint motion and reconstruct functional movements of limbs by the FES. In this study, a wirelessly powered two-channel neurostimulator was developed with the purpose of applying selective FES to two peripheral nerves-the peroneal nerve and the tibial nerve in a rat. The neurostimulator was designed in such a way that power could be supplied wirelessly, from a transmitter coil to a receiver coil. The receiver coil was connected, in turn, to the peroneal and tibial nerves in the rat. The receiver circuit had a low pass filter to allow detection of the frequency of the transmitter signal. The stimulation of the nerves was switched according to the frequency of the transmitter signal. Dorsal/plantar flexion of the rat ankle joint was selectively induced by the developed neurostimulator. The rat ankle joint angle was controlled by changing the stimulation electrode and the stimulation current, based on the Proportional Integral (PI) control method using a visual feedback control system. This study was aimed at controlling the leg motion by stimulating the peripheral nerves using the neurostimulator.

Cross-cultural translation, adaptation and validation of a Japanese version of the functional index for hand osteoarthritis (J-FIHOA).

BACKGROUND: Hand osteoarthritis (OA) has a wide spectrum of clinical presentations and physical function is one of the core domains where patients suffer. The Functional Index for Hand Osteoarthritis (FIHOA) is a leading assessment tool for hand OA-related functional impairment. Our objective was to make a Japanese version of FIHOA (J-FIHOA) and validate it among Japanese hand OA patients. METHODS: Forward and backward translation processes were completed to create a culturally adapted J-FIHOA. A prospective, observational multicenter study was undertaken for the validation process. Seventeen collaborating hospitals recruited Japanese hand OA patients who met the American College of Rheumatology criteria. A medical record review and responses to the following patient-rated questionnaires were collected: J-FIHOA, Hand20, Health Assessment Questionnaire (HAQ), numerical rating scale for pain (NRS pain) and Short Form 36 Health Survey (SF-36). We explored the structure of J-FIHOA using factor analysis. Cronbach's alpha coefficients and item-total correlations were calculated. Correlations between J-FIHOA and other questionnaires were evaluated for construct validity. Participants in clinically stable conditions repeated J-FIHOA at a one- to two-week interval to assess test-retest reliability. To evaluate responsiveness, symptomatic patients who started new pharmacological treatments had a 1-month follow-up visit and completed the questionnaires twice. Effect size (ES) and standardized response mean (SRM) were calculated with pre- and post-treatment data sets. We assessed responsiveness, comparing ES and SRM of J-FIHOA with other questionnaires (construct approach). RESULTS: A total of 210 patients participated. J-FIHOA had unidimensional structure. Cronbach's alphas (0.914 among females and 0.929 among males) and item-total correlations (range, 0.508 to 0.881) revealed high internal consistency. Hand20, which measures upper extremity disability, was strongly correlated with J-FIHOA (r = 0.82) while the mental and role-social components of SF-36 showed no correlations (r = - 0.24 and - 0.26, respectively). Intraclass correlation coefficient for test-retest reliability was 0.83 and satisfactory. J-FIHOA showed the highest ES and SRM (- 0.68 and - 0.62, respectively) among all questionnaires, except for NRS pain. CONCLUSIONS: Our results showed J-FIHOA had good measurement properties to assess physical function in Japanese hand OA patients both for ambulatory follow-up in clinical practice, and clinical research and therapeutic trials.

Acute Pain Intensity After Collagenase Clostridium histolyticum Injection in Patients With Dupuytren Contracture.

Purpose: To investigate multidimensional pain intensity and quality after collagenase Clostridium histolyticum (CCH) injection in patients with Dupuytren contracture using a pain visual analog scale (VAS) and the revised version of the Short-Form McGill Pain Questionnaire (SF-MPQ-2). Methods: This prospective observational study was carried out from 2015 to 2017. As a primary end point, patients completed the pain VAS (range, 0 [no pain] to 100) and SF-MPQ-2 before and after CCH injection; 3, 9, and 24 hours after CCH injection; after the extension procedure; and 3 and 7 days after CCH injection. In addition, they reported the dose and duration of supplementary analgesic use during this period. Results: A total of 41 patients were enrolled in this study (51 joints). Mean pain VAS score (mean ± SD, 34 ± 21) was maximal 9 hours after CCH injection and decreased within the following 7 days. The total score of the SF-MPQ-2 significantly increased after CCH treatment and decreased in the 7 days after the injection. Among the SF-MPQ-2 subscales, the highest and lowest scores after CCH injection were recorded for continuous pain and affected descriptors, respectively. Nonsteroidal anti-inflammatory drugs were most frequently self-administered during 7 days after the extension procedure compared with any other study period. Conclusions: The pain VAS and SF-MPQ-2 revealed acute pain after CCH injection. However, all examined pain aspects dramatically improved within 7 days after injection. Pain after CCH injection is characterized by low scores in the Affective Descriptors subscale of the SF-MPQ-2. Type of study/level of evidence: Prognostic Ⅳ.