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Pulvertaft tendon repair is a strong suture technique; however, proper tendon tension is impaired by repair site elongation. Therefore, methods to reduce postoperative elongation are warranted. This study aimed to determine the effects of additional core sutures during Pulvertaft tendon repair on repair site elongation and rupture strength. A total of 48 finger extensor tendons were harvested from fresh-frozen cadavers, and tendons with similar diameters were paired. The 24 pairs of tendons were divided into the following 4 groups: group I, 3 interlaced weaves only; group II, 3 interlaced weaves and 2 core suture strands with 4-0 nylon; group III, 3 interlaced weaves and 2 core suture strands with 4-0 FiberWire; and group IV, 4 interlaced weaves only. Each sutured tendon was placed in a Universal Testing Machine, and repair site elongation after repeated traction loads and rupture strength were measured. The mean elongation values were 2.74 ± 0.84 mm, 1.80 ± 0.16 mm, 1.60 ± 0.18 mm, and 1.92 ± 0.18 mm for groups I, II, III, and IV, respectively. The elongation values were significantly lower in groups II, III, and IV than in group I. The mean rupture strengths were 64.9 ± 16.0 N, 94.8 ± 17.2 N, 110.9 ± 21.3 N, and 104.9 ± 17.5 N for groups I, II, III, and IV, respectively. Rupture strengths were significantly higher for groups III and IV than for group I. After adding core sutures during Pulvertaft tendon repair, the elongation amount decreased, and the rupture strength improved. The study showed the effect of additional core sutures during Pulvertaft tendon repair, suggesting that it could be useful in reducing postoperative tendon elongation when extensor tendon transfers are performed. [ABSTRACT FROM AUTHOR]

Purpose To measure distances from anatomical landmarks to the median nerve, and estimate the length of the flexor-pronator/flexor carpi ulnaris (FCU) detachment necessary to expose the anteromedial facet of the ulnar coronoid process (UCP) using the Hotchkiss over-the-top approach. Methods Dissections were made of 20 fresh-frozen cadaveric upper limbs. Measurements were made of the shortest distance from the medial epicondyle to the median nerve, the distance from the medial epicondyle to the median nerve in line with the flexor-pronator/FCU interval, the shortest distance from the apex of the UCP to the median nerve, and the length of the flexor-pronator/FCU detachment necessary to expose the anteromedial facet of the UCP. Measurements were also made of the length of the ulnar insertion of the brachialis muscle and the shortest distances from the proximal and distal insertions of the brachialis muscle to the median nerve. Results The distances and lengths were as follows: medial epicondyle to median nerve, 31 ± 3 mm; in line with the flexor-pronator/FCU interval, 43 ± 5 mm; from the apex of the UCP to the median nerve, 7 ± 2 mm; the detachment necessary to expose the UCP, 47 ± 6 mm; the ulnar insertion of the brachialis muscle, 27 ± 4 mm; and the proximal and distal insertions of the brachialis muscle to the median nerve, 14 ± 2 mm and 5 ± 1 mm, respectively. Conclusions The length of the flexor-pronator/FCU detachment necessary to expose the anteromedial facet of the UCP was similar to the distance from the medial epicondyle to the median nerve in line with the flexor-pronator/FCU interval. The distance from the distal insertion of the brachialis muscle to the median nerve was 5 mm. Clinical relevance The results of our study provide information on important points for surgeons to consider when performing distal exposure using the Hotchkiss over-the-top approach. [ABSTRACT FROM AUTHOR]

Purpose To assess the anatomic feasibility of a median-to-radial nerve transfer in cadaver limbs and to quantify the number of axons present in the cut ends of the involved donor and recipient nerves. Methods Ten fresh frozen cadaveric upper limbs were dissected. We investigated whether the flexor carpi radialis (FCR) branch/flexor digitorum superficialis (FDS) branch (donor nerve) reached the posterior interosseous nerve (PIN)/extensor carpi radialis brevis (ECRB) branch (recipient nerve) without tension. We also investigated the length of the transected supinator fascia for FCR-posterior interosseous nerve transfer and the FDS-ECRB positional relationship using the epicondyle line and the midline of the forearm as axes. The findings were used for these 2 types of nerve transfer with evaluation closer to the target muscles. The distance between the point at which the FDS and ECRB branches met and the point at which the ECRB branch entered the muscle was measured. After nerve coaptation, the axon number was determined by histological evaluation. Results In all limbs, the FCR and FDS branches reached the PIN and the ECRB branch without tension. The transected supinator fascia was 17 (3–25) mm long. The distance between the FDS and ECRB branches was 48 (23–65) mm distal to the epicondyle line and approximately 23 (18–27) mm radial to the midline of the forearm. The distance between the point at which the FDS and ECRB branches met and the point at which the ECRB branch entered the muscle was 27 (17−40) mm. The mean axon numbers were FCR, 1501 (932–3022); PIN, 5162 (4325–7732); FDS, 885 (558–962); and ECRB, 548 (433–723). Conclusions The FCR branch could be transferred to the PIN branch and the FDS to the ECRB branch in all limbs without tension. Clinical relevance We provide anatomical and histological information for median-to-radial nerve transfer. [ABSTRACT FROM AUTHOR]

Purpose To compare the mechanical properties of sliding lengthening (SL) and Z-lengthening (ZL) for flexor tendon elongation used for conditions such as Volkmann contracture, cerebral palsy, and poststroke spasticity. Methods We harvested 56 flexor tendons, including flexor pollicis longus tendons, flexor digitorum superficialis tendons (zones II to IV), and flexor digitorum profundus tendons (zones II to V) from 24 upper limbs of 12 fresh cadavers. Each tendon was harvested together with its homonymous tendon from the opposite side of the cadaver and paired. We used 28 pairs of tendons and divided them randomly into 4 groups depending on the lengthening distance (20 or 30 mm) and type of stitching (single or double mattress sutures). Then we divided each pair into either the SL or ZL group. Each group was composed of 7 specimens. The same surgeon lengthened all tendons and stitched them with 2-0 polyester sutures. We tested biomechanical tensile strength immediately after completing lengthening and suturing in each group. Results Ultimate tensile strengths were: 23 N for the SL 20-mm lengthening and single mattress suture and 7 N for the ZL; 25 N for the SL 20-mm lengthening and double mattress suture and 10 N for the ZL; 15 N for the SL 30-mm lengthening and single mattress suture and 8 N for the ZL; and 18 N for the SL 30-mm lengthening and double mattress suture and 10 N for the ZL. Conclusions The SL technique may be a good alternative to the ZL technique because it provides higher ultimate tensile strength. Clinical relevance Because of its higher ultimate tensile strength, the SL technique may allow for earlier rehabilitation and reduced risk of postoperative complications. [ABSTRACT FROM AUTHOR]

Purpose To investigate the effect of intraperitoneal administration of an anti-p75 neurotrophin receptor (p75NTR) antibody on reducing neuropathic pain in a rat model of brachial plexus avulsion (BPA). Methods We randomly assigned 40 male Wistar rats to 4 groups. In the BPA group, the C8-T1 roots were avulsed from the spinal cord at the lower trunk level, and saline was administered intraperitoneally. In the anti-p75NTR groups, 1 μL or 50 μL anti-p75NTR antibody was administered intraperitoneally after avulsion. In the sham-operated group, the lower trunk level was exposed, and saline was administered intraperitoneally. Mechanical hyperalgesia and pain-induced walking patterns were measured using von Frey filaments and CatWalk gait analysis at various time points until 15 days after administration. At 3 and 15 days after administration, sensory neurons involved in pain perception and satellite glial cells in the ipsilateral C7 dorsal root ganglia were immunolabeled with antibodies against calcitonin gene-related peptide and glial fibrillary acidic protein (GFAP), respectively. At both time points, microglial and astrocyte activation, indicative of spinal pain transmission, were immunohistochemically examined in the ipsilateral dorsal horn of the spinal cord (C7) using anti-ionized calcium-binding adaptor molecule 1 and anti-GFAP antibodies, respectively. Results The gait pattern was significantly improved in both anti-p75NTR groups compared with the BPA group. There were significantly fewer calcitonin gene-related peptide-immunoreactive (IR) neurons, neurons encircled by GFAP-IR satellite glial cells, and GFAP-IR astrocytes in both anti-p75NTR groups compared with the BPA group at both time points. Fewer ionized calcium-binding adaptor molecule 1-IR microglia were quantified in both anti-p75NTR groups compared with the BPA group, but this was only significant at 15 days after administration. Conclusions Systemic application of the p75NTR inhibitory antibody suppressed neuropathic pain after BPA. Clinical relevance p75NTR may be a potential therapeutic target for the clinical treatment of neuropathic pain in BPA injury. [ABSTRACT FROM AUTHOR]

Purpose Patients with idiopathic carpal tunnel syndrome are commonly treated by steroid injections into the carpal tunnel. We administered triamcinolone (Tr) to chronic constriction injury model rats. We hypothesized that Tr administration would have both favorable behavioral effects and quantifiable immunohistological effects on compressed nerves. Methods Thirty-six male Wister rats were used. For rats to be treated with Tr, we loosely ligated their right sciatic nerves at 4 sites. Sham rats had their nerves exposed without ligation. On postoperative day 7, we reexposed their ligated nerves, after which we delivered either 0.1 mg of Tr (0.1-mg group), 0.5 mg of Tr (0.5-mg group), or normal saline (saline group) around the nerve fibers at the injured sites. Gait was analyzed, and allodynia was assessed with von Frey hairs, before surgery and on postoperative days 3, 7, 10, 14, and 21. The right sciatic nerve was resected and stained using hematoxylin-eosin, and the fourth and fifth lumbar dorsal root ganglia (DRG) were removed and assessed by immunohistochemistry for calcitonin gene-related peptide (CGRP) and activating transcription factor 3 (ATF3) on postoperative day 21. In addition, interleukin-1β (IL-1β) in sciatic nerve was quantified using enzyme-linked immunosorbent assays. Results Mechanical allodynia was significantly decreased in the 0.5-mg group compared with the saline group. In hematoxylin-eosin sections, the extent of inflammation-induced edema between the nerve fibers and infiltration of inflammatory cells was significantly reduced in the 0.5-mg group compared with the saline group. IL-1β levels at the sciatic nerve in the 0.5-mg group were significantly lower than those in the saline group. Conclusions Tr-treated chronic constriction injury rats exhibited significant alleviation of sensory disturbance, edema, inflammation, and pain-related peptide upregulation. These phenomena suggest the validity of Tr administration as a treatment affecting the nerve itself. Type of study/level of evidence Therapeutic I. [ABSTRACT FROM AUTHOR]

Purpose: Brachial plexus pain is thought to be generated not by avulsed roots but rather by nonavulsed roots, because avulsed roots could not transmit action potentials to central nerves. The aim of this study was to evaluate pain-related behavior and the extent of glial activation in a model of brachial plexus avulsion (BPA). Methods: We used 24 male Wistar rats. For rats in the BPA group, the C8–T1 roots were avulsed from the spinal cord at the level of the lower trunk (n = 10). Rats in a sham-surgery group had a similar surgery without the root avulsion (n = 7). Rats in an untreated group had no surgery (n = 7). Mechanical hyperalgesia of the forelimb plantar surfaces corresponding to C6 and C7 dermatomes was evaluated using a Semmes-Weinstein monofilament test every third day for 3 weeks (n = 15). Activation of astrocytes and microglia was examined immunohistochemically using anti-glia fibrillary acidic protein and anti-Iba1 antibodies 3 days after surgery (n = 9). Results: When compared with rats in the sham-surgery and naive control groups, rats in the BPA group displayed significant mechanical hyperalgesia in the dermatome innervated by uninjured nerves both ipsilaterally and contralaterally and continuing through day 21. Iba1-immunoreactive microglia and glia fibrillary acidic protein–immunoreactive astrocytes were significantly activated on the ipsilateral side in the BPA group from levels C3 to T3 compared with the sham-surgery and untreated groups of rats. Conclusions: Activation of glia at uninjured levels of the dorsal horn may facilitate pain transmission following BPA injury. Consequently, spared spinal glial cells may represent therapeutic targets for treatment of pain related to BPA injury. Clinical relevance: Our findings may indicate why neuropathic pain is so frequent and intense following BPA injury. [ABSTRACT FROM AUTHOR]

Purpose: The Fowler tenotomy, adjusting the balance of the extensor mechanism by central slip and lateral band detachment, is a common surgical technique for chronic mallet finger. The purpose of this study was to determine how much tendon to detach from the middle phalanx by measuring the extensor lag of the distal interphalangeal (DIP) joint following the procedure and to quantify how often a boutonniere deformity occurred as a consequence of the procedure. Methods: Sixteen fingers were obtained from 8 fresh-frozen cadaver hands. We made mallet finger deformity models by terminal tendon elongation. We detached the central slip and lateral band from the middle phalanx by one-third, one-half, and two-thirds of the phalangeal length and measured extensor lag of the DIP and proximal interphalangeal joints before and after this procedure. Results: In these models, the average extensor lag of the DIP joint was 44° (range, 40° to 50°). After central slip and lateral band detachment over one-third of the phalangeal length, the average residual extensor lag of the DIP joint was 19° (range, 0° to 40°). With one-half detachment, the average lag was 13° (range, 0° to 35°), and with two-thirds detachment, the average lag was 6° (range, 0° to 15°). Extensor lag at the proximal interphalangeal joint occurred in 4 fingers, with an average lag of 8° (range, 5° to 15°). Conclusions: In the Fowler tenotomy models, detachment of the central slip and lateral band from the middle phalanx reduced extensor lag of the DIP joint. Detachment of up to two-thirds of the phalangeal length was effective in this model and did not cause any boutonniere deformity. Clinical relevance: Controlled clinical application of our cadaveric results might yield improved active motion for chronic mallet extensor lag. [ABSTRACT FROM AUTHOR]

Purpose: Although the end-to-side nerve repair technique has been used clinically, it has not yet produced consistent motor and sensory recovery in patients. The aim of this study was to investigate whether end-to-side double nerve grafts display more axonal regeneration compared with a single nerve graft in a rat lower limb preparation. Methods: The lower limbs of 96 Wister rats were used in experiments comparing single and double end-to-side nerve grafts. Left peroneal nerves were harvested and grafted between the right peroneal and tibial nerves. A single graft was attached end-to-side to the peroneal and tibial nerves through an epineural window (single graft group, n = 24). Two grafts were performed in the same manner in the double graft group (n = 24). The peroneal nerve was exposed in positive controls (n = 24) and no graft was performed in negative controls (n = 24). We recorded action potentials and moist weights of the left tibialis anterior muscle at each time point. Fluoro-Gold-labeled (Fluorochrome, Denver, CO) dorsal root ganglion neurons from L1 to L6 were counted using fluorescence microscopy and compared among the 4 groups. Results: In both single and double groups, the amplitude and the tibialis anterior muscle weight increased significantly compared with negative controls but remained lower than those measured in positive controls. There was no significant difference between single and double groups. In Fluoro-Gold-labeled neurons, there was also no significant difference between single and double groups. Conclusions: The study showed that regeneration of motor and sensory nerve fibers was possible using 2 end-to-side nerve grafts. However, there was no significant difference between single and double grafts. This might suggest a therapeutic limitation of nerve transplants using 2 end-to-side nerve grafts. Clinical relevance: Double end-to-side repair attracts both motor and sensory axons, and this results in a medium degree of recovery of function; however, double end-to-side nerve grafting does not appear to offer any advantage over a single end-to-side graft. [ABSTRACT FROM AUTHOR]

Purpose: Nerve growth factor (NGF), via the high-affinity receptor, tyrosine kinase A, has been widely reported as a mediator of pain caused by inflammation. A clinical trial has suggested that anti-NGF antibody is effective for pain caused by osteoarthritis of the knee. However, adverse events such as headache (8.9%), upper respiratory tract infection (7.3%), and paresthesia (6.8%) were reported. We hypothesized that inhibition of the low-affinity NGF receptor, p75 neurotrophin receptor (p75NTR), is also effective for joint pain and may reduce side effects. This study examined suppression of pain behavior and expression of pain-inducing neuropeptides such as calcitonin gene-related peptide (CGRP) and p75NTR in dorsal root ganglia neurons by a p75NTR inhibitory antibody in a rat model of wrist joint inflammatory pain. Methods: We injected complete Freund''s adjuvant (CFA) into the wrist joint of rats and used this as a model of inflammatory pain. We applied 10 μL of saline (CFA + saline group; n = 20) or 1, 10, or 50 μL of a p75NTR inhibitory antibody (CFA + p75NTR inhibitory antibody group; n = 40) directly to the inflamed joint in the rats. Mechanical hyperalgesia was measured for 2 weeks using von Frey filaments. We assessed CGRP and p75NTR expression in C8 dorsal root ganglia immunochemically. Adverse events such as loss of weight and/or appetite, constipation, and infection were examined. Results: p75NTR inhibitory antibody reduced mechanical hyperalgesia caused by CFA (p<.05 vs controls) in the rat model (p<.01 vs saline), without any adverse events. We found that 10 and 50 μL of a p75NTR inhibitory antibody were more effective for pain, without a significant difference between doses. CGRP and p75NTR immunoreactivity was upregulated in the CFA + saline groups compared with a control group (p<.01). However, direct p75NTR inhibitory antibody application decreased CGRP and p75NTR expression after wrist inflammation (p<.01). Conclusions: p75NTR inhibition may be a therapeutic target for inflamed joint pain treatment with reduced adverse events. [Copyright &y& Elsevier]

Purpose Forearm diaphysis fractures are usually managed by open reduction internal fixation. Recently, locking plates have been used for treatment. In the long-term period after surgery, some patients present with bone atrophy adjacent to the plate. However, a comparison of locking and conventional plates as a cause of atrophy has not been reported. The aim of this study was to investigate long-term bone atrophy associated with use of locking and conventional plates for forearm fracture treatment. Methods In this study we included 15 patients with forearm fracture managed by either locking or conventional plates and with more than 5 years of follow-up. Computed tomographic imaging of both forearms was performed to assess bone thickness and local bone mineral density and to predict bone strength without plate reinforcement based on finite element analysis. Results Mean patient age at surgery was 48.0 years. Eight patients underwent reduction with fixed locking plates and were followed up for a mean of 79.5 months; the remaining 7 patients were treated with conventional plates and were followed up for a mean of 105.0 months. Compared with the conventional plate group, the locking plate group had the same fractured limb–contralateral limb ratio of cortex bone thickness, but had significantly lower ratios of mineral density adjacent to the plate and adjusted bone strength. Conclusions This study demonstrated bone atrophy after locking plate fixation for forearm fractures. Treatment plans for forearm fracture should take into consideration the impact of bone atrophy long after plate fixation. Type of study/level of evidence Therapeutic IV. [ABSTRACT FROM AUTHOR]