[The effect of different diagnostic standards on the diagnosis of suspected occupational noise-induced deafness].

Objective: To explore the effect of different diagnostic criteria on occupational noise-induced deafness (Onid) , and to provide theoretical basis for the revision of ONID diagnostic criteria. Methods: From January 2016 to January 2018, the physical examination results of noise-exposed workers during occupational health examination in Qingyuan Occupational Disease Prevention and Treatment Hospital were retrospectively investigated in September 2019, with Gbz 49-2014《diagnosis of occupational noise deafness》as the study object, 471 workers suspected of Onid were weighted with different combinations of high frequency hearing threshold, and the better ear weight was calculated, compared with the diagnostic criteria of 2007 and 2014, the degree of hearing loss was evaluated. SPSS 22.0 was used for statistical analysis, χ(2) test was used for counting data, and non-parametric test was used for measuring bias data. Results: The average age of 471 subjects was (40.32±7.01) years, and the average age of exposure to noise was (7.11±3.44) years. On the basis of the 2007 edition diagnostic standard, the suspected ONID diagnostic rate of different high frequency auditory threshold was increased by 16.35% and 30.15% at 3.0 kHz, 6.0 kHz increased by 20.17%, 3.0 kHz+4.0 kHz increased by 22.29%, 3.0 kHz+6.0 kHz increased by 17.20%, 4.0 kHz+6.0 kHz increased by 25.27%, the differences were statistically significant (P<0.05) , the frequency of 3.0 kHz+4.0 kHz+6.0 kHz increased by 22.29%. Using the 2014 edition diagnostic standard, the diagnostic rate of Onid was reduced by 30.15% and 13.80%, 6 kHz is 9.98% lower, 3.0 kHz+4.0 kHz is 7.86% lower, 3.0 kHz+6.0 kHz is 12.95% lower, 4.0 kHz+6.0 is 4.88% lower, the high frequency of 3.0 kHz+4.0 kHz+6.0 kHz decreased by 7.86%, the differences were statistically significant (P<0.05) . Conclusion: The diagnosis rate of suspected Onid is increased by weighting different high frequency hearing threshold, in which the weighted 4kHz high frequency has the greatest influence on the result, and the weighted 3 kHz high frequency has the least.

Modulation of digital flexor tendon healing by vascular endothelial growth factor gene transfection in a chicken model.

A major challenge in tendon injury is the weak intrinsic healing capacity of tendon that may cause rupture of the repair after surgery. Growth factors are believed to be critical during tendon healing. This study aimed to investigate the effects of vascular endothelial growth factor (VEGF) genes delivered by adeno-associated virus (AAV) vectors on tendon healing and molecular events involved in a chicken model. A total of 128 deep flexor tendons in the long toes of chickens were completely transected and injected with 2 × 109 particles of AAV2-VEGF or saline before surgically repaired. At postoperative 4, 6 and 8 weeks, the gliding excursions of tendon were recorded and adhesions around the repair site scored. At 2, 4, 6 and 8 weeks, the ultimate strengths of the healing tendons were tested. Terminal deoxynucleotide transferase dUTP nick end labeling assay were performed to detect cellular apoptosis and immunofluorescence staining to detect type III collagen and matrix metalloprotease-2 (MMP2) expression in tendon tissues. The gliding excursion and adhesion score were similar between AAV2-VEGF-treated tendons and the control tendons. Delivery of AAV2-VEGF significantly increased ultimate strength of the healing tendons at postoperative 4, 6 and 8 weeks (P<0.05). Apoptotic reaction was inhibited from postoperative 2 to 8 weeks in tendon core area or surface area. Type III collagen expression was enhanced at 2, 4, 6 and 8 weeks and MMP2 expression enhanced at 2 and 4 weeks after AAV2-VEGF transfection. The current study confirms the therapeutic efficacy of AAV2-VEGF in improving healing strength of tendon without aggravating adhesion formation after tendon injury, shedding light on the application of molecular therapy in modulating tendon healing.

Adeno-associated virus-2-mediated TGF-ß1 microRNA transfection inhibits adhesion formation after digital flexor tendon injury.

Adhesion formation after digital flexor tendon injury greatly affects gliding function of the tendon, which is a major clinical complication after hand surgery. Transforming growth factor beta 1 (TGF-ß1) has a critical role in adhesion formation during tendon healing. Persistent regulation of TGF-ß1 through application of microRNA (miRNA) specifically inhibiting the function of TGF-ß1 (TGF-ß1-miRNA) holds promise for treatment of such a complication. Adeno-associated virus (AAV) was used to transfer TGF-ß1-miRNA to the chicken digital flexor tendons, which had been injured and surgically repaired. Four doses of AAV2-TGF-ß1-miRNA (2 × 10¹¹, 2 × 10¹°, 2 × 109 and 2 × 108 vector genomes (vg)) were used to determine the transfection efficiency. At postoperative 3 weeks, we found a positive correlation between the administered AAV2-TGF-ß1-miRNA doses and transfection efficiency. The transfection rate ranged from 10% to 77% as the doses increased. Production of TGF-ß1 protein in the tendons decreased on increasing vector dosage. When 2 × 10¹¹ and 2 × 10¹°) vg were injected into the tendon, gliding excursion of the repaired tendon and work of flexion of chicken toes were significantly increased and adhesion score decreased 6 and 8 weeks later, indicating the improvement of tendon gliding and decreases in adhesion formations. However, the ultimate strength of the tendons transfected at the dose of 2 × 10¹° vg was 12-24% lower than that of the control tendons. The results of this study demonstrate that application of TGF-ß1-miRNA had a mixed impact on tendon healing: adhesion around the tendon is reduced but strength of the tendon healing is adversely affected. Future studies should aim at maintaining the beneficial effects of reducing tendon adhesions, while eliminating the adverse effects of decreasing the healing strength.

An ordinary differential equation model for full thickness wounds and the effects of diabetes.

Wound healing is a complex process in which a sequence of interrelated phases contributes to a reduction in wound size. For diabetic patients, many of these processes are compromised, so that wound healing slows down. In this paper we present a simple ordinary differential equation model for wound healing in which attention focusses on the dominant processes that contribute to closure of a full thickness wound. Asymptotic analysis of the resulting model reveals that normal healing occurs in stages: the initial and rapid elastic recoil of the wound is followed by a longer proliferative phase during which growth in the dermis dominates healing. At longer times, fibroblasts exert contractile forces on the dermal tissue, the resulting tension stimulating further dermal tissue growth and enhancing wound closure. By fitting the model to experimental data we find that the major difference between normal and diabetic healing is a marked reduction in the rate of dermal tissue growth for diabetic patients. The model is used to estimate the breakdown of dermal healing into two processes: tissue growth and contraction, the proportions of which provide information about the quality of the healed wound. We show further that increasing dermal tissue growth in the diabetic wound produces closure times similar to those associated with normal healing and we discuss the clinical implications of this hypothesised treatment.

The mode of reproductive-derived Spink (serine protease inhibitor Kazal-type) action in the modulation of mammalian sperm activity.

The reproductive-derived serine protease inhibitor Kazal-type (Spink) has been identified in seminal plasma, and Spink-spermatozoa binding has been illustrated in many mammalian species including human. We used mice as experimental animal to study the mode of Spink action in the modulation of mammalian sperm activity. A Spink3-binding zone was cytochemically stained on the sperm head at apical hook separated from intact acrosome, whether the cells were capacitated or not. The Spink3-spermatozoa binding neither changed the population of cells in the uncapacitated, capacitated and acrosome-reacted status nor affected the capacitation-related protein phosphorylation and cell motility enhancement. Despite that, the Spink-spermatozoa interaction resulted in decreasing the intracellular calcium concentration ([Ca(2+)](i)) of the cell head and suppressing both the acrosome reaction induced by Ca(+2) ionophore A23187 and the cell fertility. Furthermore, Spink3 seen on the head of spermatozoa in the uterine cavity after coitus could be removed by the trypsin-like activity in the uterine fluid of oestrous females, and free Spink3 in the uterine cavity suppressed the protease activity. We integrated our data to shed light on the molecular mechanism of how Spink and its inhibiting protease are interplayed to modulate the activity of mammalian spermatozoa during their transit in the reproductive tract.

Mir-451 inhibits proliferation and migration of non-small cell lung cancer cells via targeting LKB1/AMPK.

OBJECTIVE: To discuss the influence of micro ribonucleic acid (miR)-451 on cell proliferation and apoptosis of non-small cell lung cancer (NSCLC) by regulating liver kinase B1 (LKB1) signals and activating adenosine monophosphate-activated protein kinase (AMPK). MATERIALS AND METHODS: Lung cancer A549 cells were divided into control group, miR-451 mimic group, and miR-451 inhibitor group. The cell proliferation and migration ability, as well as the expression of LKB1 and AMPK in the three groups, were determined via Reverse Transcription-Polymerase Chain Reaction (RT-PCR), transwell assay, and cell counting kit-8 (CCK8) assay, respectively. RESULTS: Compared with that in control group, the number of migrating cells evidently declined in miR-451 mimic group, while that in miR-451 inhibitor group was significantly increased, and the differences were statistically significant (p < 0.05). At 7 d of cell culture, the cell proliferation ability in miR-451 mimic group was higher than that in control group, while it was higher in control group than that in miR-451 mimic group, and there were significant differences among the three groups (p < 0.05). The expression of LKB1 and AMPK was significantly decreased in miR-451 mimic group compared with that in miR-451 inhibitor group and control group, and the differences had statistical significance (p < 0.05). The differences in activities of LKB1 and AMPK between miR-451 inhibitor group and control group were not significant (p > 0.05). CONCLUSIONS: LKB1/AMPK can be involved in the cell metabolism of NSCLC and miR-451 is negatively correlated with LKB1/AMPK. Therefore, miR-451 may inhibit cell proliferation and migration of NSCLC via regulating LKB1/AMPK.

HCP5 promotes colon cancer development by activating AP1G1 via PI3K/AKT pathway.

OBJECTIVE: To explore whether HCP5 participates in the pathogenic progression of colon cancer (CC) and its underlying mechanism. PATIENTS AND METHODS: HCP5 expression in CC tissues and cell lines was detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). The correlation between the HCP5 expression and tumor stage of CC patients was then analyzed. After CC cells were transfected with HCP5-siRNA, the proliferation and migration capacities were detected by cell counting kit-8 (CCK-8), colony formation and transwell assay, respectively. Cell cycle was examined by flow cytometry. Western blot was conducted to detect protein expressions of HCP5, AP1G1 and relative molecules in the PI3K/AKT pathway. Rescue experiments were performed by co-transfection of HCP5-siRNA and AP1G1-siRNA into CC cells, followed by cell function detection. RESULTS: HCP5 was highly expressed, whereas AP1G1 was lowly expressed in CC tissues and cell lines. Besides, CC patients with stage III-IV presented higher expression of HCP5 than those with stage I-II. The knockdown of HCP5 in CC cells down-regulated proliferation and migration capacities, and arrested cell cycle in the G0/G1 phase, which was reversed by the AP1G1 knockdown. In addition, HCP5 knockdown up-regulated AP1G1 expression, whereas down-regulated the expression of relative proteins in the PI3K/AKT pathway. CONCLUSIONS: HCP5 was significantly increased in CC and enhanced the proliferation and migration of CC cells by inhibiting the AP1G1 expression. HCP5 promoted CC development by activating the PI3K/AKT pathway.

Biomechanical evaluation of a four-strand modification of the Tang method of tendon repair.

We report a four-strand modification of the Tang technique of tendon repair that uses fewer sutures and fewer knots on the tendon surface. This repair consists of four longitudinal and two horizontal strands that form a "U" configuration within the tendon made with a single looped suture. Thirty-four fresh pig flexor tendons were divided into 3 groups and repaired with the four-strand modified Tang method, a double-looped four-strand method or a double Kessler repair (four-strand). The tendons were subjected to a single cycle of load-to-failure test in a tensile testing machine. The initial force, 2-mm gap formation force and ultimate strength of the four-strand modified Tang repair were statistically identical to those of the double looped suture and were superior to those of the double Kessler repair. Ultimate strength was 43.4+/-4.3N for the four-strand modified Tang method, 45.2+/-4.0N for the double-looped method and 39.1+/-4.0N for the double Kessler repair. The four-strand modification of the Tang method appears to have strength sufficient for protected active finger motion. Given our preliminary clinical experience with this method, we recommend this new and simplified technique for clinical flexor tendon repairs.

In Vivo changes in the lengths of carpal ligaments after mild dorsal angulation of distal radius fractures.

The need for surgical correction in patients with malunion with mild dorsal angulation after a distal radius fracture is controversial. We specifically investigated in vivo changes in the lengths of carpal ligaments in a group of patients with mild-degree dorsal angulation following a distal radial fracture. We obtained computed tomography scans of both wrists in eight patients, whose distal radius on one side had united with dorsal angulation from 10° to 20°. The three-dimensional images of the carpus were reconstructed and the lengths of wrist ligaments were measured based on known anatomical landmarks. Compared with the contralateral uninjured side, the dorsal radiocarpal ligament and ulnotriquetral ligament were substantially lengthened (p < 0.05) and the long radiolunate ligament was substantially shortened (p < 0.05) at most wrist positions except extension. However, five other ligaments that we measured did not show significant differences in length compared with those of the uninjured side (p > 0.05). The lengths of some ligaments are substantially altered even by mild dorsal angulation of the distal radius, while the lengths of most other ligaments are not substantially affected.

Overview of indications, preferred methods and technical tips for hand fractures from around the world.

This article presents techniques used by six senior surgeons from different parts of the world. Our commentaries on treating hand fractures are included, together with the methods we use. While non-operative treatment is appropriate and effective for the majority of the hand fractures (including those many practitioners currently treat surgically), we describe how we try to manage difficult cases with less invasive surgical methods. We recommend simple, efficient, non-operative or less invasive operative methods for almost all fractures, except for some open or very complex injuries.

Effect of radial shortening on muscle length and moment arms of the wrist flexors and extensors.

The purpose of this study was to determine the effect of distal radial shortening on muscle length and moment arm of the wrist flexors and extensors. In eight cadaveric upper extremities, distal radius fractures were simulated by an ostectomy. The distal radius was progressively shortened by 2.5, 5.0, 7.5, and 10 mm. Changes in the resting length of the flexor carpi radialis and ulnaris, extensor carpi radialis longus and brevis, and extensor carpi ulnaris muscles were measured with rotary potentiometers at neutral position, flexion, extension, and radial and ulnar deviation of the wrists. The wrists were passively moved through flexion-extension and radioulnar deviation, and tendon excursions and wrist joint angulation were recorded simultaneously. Tendon moment arms were derived from tendon excursions and joint motion. The results showed that either muscle length or moment arm of the principal wrist flexors and extensors was significantly affected by the radial shortening. Muscle length decreased significantly after radial shortening in all the wrist flexors and extensors except for the extensor carpi ulnaris. The moment arm of the extensor carpi ulnaris tendon decreased significantly during either wrist flexion-extension or radioulnar deviation. The extensor carpi radialis brevis and flexor carpi ulnaris tendons also showed a significant decrease in their moment arms during radioulnar deviation of the wrist. Radial shortening of only 2.5 mm caused statistically significant changes in muscle length and moment arm of the wrist flexors and extensors. Increasing the extent of radial shortening exaggerated the biomechanical changes in the wrist motors. These results validate the importance of normal radial length for wrist kinetics and, from a biomechanical perspective, support complete correction of radial shortening after distal radius fractures.

The presence of smooth muscle actin in fibroblasts in the torn human rotator cuff.

The rotator cuff frequently sustains athletic and occupational injury, often resulting in chronic pain and disability. However, despite the high incidence of such shoulder problems, the pathophysiology of rotator cuff injury and healing has not yet been fully elucidated. The notable finding of this study was the presence of a contractile actin isoform, alpha-smooth muscle actin (SMA), in nonvascular cells in all of the seven torn human rotator cuff specimens evaluated immunohistochemically. Up to 95% of cells in any one region, and over 95% of elongated cells found in association with crimped collagen, contained SMA. Most of the cells staining positive for SMA in these sections had morphological features of the fibroblast, though a small number were chondrocyte-like. Treatment of cells growing out from human rotator cuff explants with TGF-beta1 significantly increased the amount of SMA evaluated by Western blot analysis. PDGF-BB and IFN-gamma had no effect on the cell content of SMA. This is the first documentation of the presence of SMA-positive cells in the human rotator cuff tendon. SMA has been found in a number of other healing connective tissues including skin, ligament, meniscus, cartilage, and other types of tendon. Of importance are previous findings that SMA-positive cells can contract a collagen-glycosaminoglycan analog of extracellular matrix in vitro. The results of the present study thus suggest that SMA-containing cells could contribute to the retraction of the torn ends of a ruptured rotator cuff and play an important role in healing.

Biomechanical changes of the wrist flexor and extensor tendons following loss of scaphoid integrity.

Loss of integrity of the scaphoid may change the motion center of the entire carpus, and deformities from scaphoid fractures may alter the location of motor tendons of the wrist, thus altering their biomechanics. The goal of this study was to clarify biomechanical changes in these tendons following loss of scaphoid integrity. Excursions and moment arms of the principal flexor and extensor tendons of the wrist were investigated in seven cadaveric upper extremities in intact wrists after simulation of scaphoid waist fracture and after removal of the proximal scaphoid. Excursions of the flexor carpi radialis and ulnaris, extensor carpi radialis longus and brevis, and extensor carpi ulnaris tendons were measured with rotary potentiometers during wrist flexion-extension and radioulnar deviation. Simultaneously, wrist joint angulation was recorded. Moment arms of the tendons were derived from tendon excursions and joint motion. After scaphoid fracture, the moment arms of the flexor carpi radialis and extensor carpi ulnaris tendons increased significantly during wrist flexion-extension, whereas the moment arms of the extensor carpi radialis longus and brevis tendons decreased significantly. After proximal scaphoid excision, the moment arms of the extensor carpi radialis longus and brevis tendons again decreased significantly during wrist flexion-extension. The moment arms of the flexor carpi radialis and extensor carpi radialis brevis tendons increased significantly during radioulnar deviation, whereas those of the wrist motors on the ulnar side decreased. These findings indicate the importance of the integrity of the scaphoid in maintaining normal biomechanics of motor tendons of the wrist. An increase in the moment arm of the radial wrist flexor along with a decrease in moment arms of the radial extensors constitutes as etiology for persistent angulation of the scaphoid and the humpback deformity. In addition, disturbing the biomechanics of the wrist motor tendons predisposes the carpal joints to abnormal loading, potentially contributing to the development of carpal joint degeneration.

Regulation of expression of alpha-smooth muscle actin in cells of Dupuytren's contracture.

Our aims were to describe the distribution of alpha-smooth muscle actin (SMA)-containing cells in Dupuytren's tissue in vivo and to determine the effects of selected agents in regulating the expression of SMA in Dupuytren's cells in vitro. In selected hypercellular zones of Dupuytren's nodules up to 40% of the cells contained SMA, as shown by immunohistochemistry. A lower percentage (20%) of SMA-containing cells was found in regions of lower cellularity. A notable finding was that treatment in vitro of Dupuytren's cells with platelet-derived growth factor significantly reduced the content of SMA. Cells from the same patients showed a significant increase in expression of SMA in response to treatment with transforming growth factor, which confirmed recent findings. In addition, interferon-gamma, which has been previously used as a treatment for Dupuytren's disease in a clinical study, had no reproducible effect on the expression of this actin isoform. Our findings are of significance for the conservative management of contractures.

Vascular and neural anatomy of the thenar area of the hand: its surgical applications.

Thirty fresh cadaver hands were injected with a silicone rubber compound (Microfil) and dissected to examine the vascular and neural supplies of the thenar area. In 10 specimens, a selective injection technique was used to determine the extent of skin territory nourished by the superficial palmar branch of the radial artery. The purpose of this study was to clarify the anatomic basis for clinical applications of vascularized free- or island-flap transfers from the thenar area. The superficial palmar branch of the radial artery was found in all hands; the average diameter of the branch measured at its bifurcation site was 1.4 mm (0.8 to 3.0 mm). The constant area nourished by the superficial palmar branch was an area approximately 4 x 3 cm located over the proximal parts of the abductor pollicis brevis and opponens pollicis muscles. These results indicate that a fasciocutaneous flap from the radial thenar region can be raised based on the superficial palmar branch and consistently transferred as a free flap. In 63 percent of the hands dissected, the superficial palmar branch was connected to other arteries in the palm, suggesting that the flap can be transferred as a reverse-pedicle island flap in such hands. Innervation of the flap was provided chiefly by a branch of the superficial radial nerve. The radial aspect of the thenar eminence can provide a new and useful donor source for an innervated and vascularized free- or island-flap transfer for reconstruction of various skin defects of the volar side of the fingers.

Evaluation of four methods of flexor tendon repair for postoperative active mobilization.

Active mobilization of repaired flexor tendons requires sufficient suture strength. This study was designed to investigate the suitability of four newly developed and comparatively strong tendon sutures for flexor tendon repair with active digital mobilization. Fifty fresh flexor digitorum profundus tendons were randomly assigned to five groups and repaired using the Tang, cruciate, Robertson, Silfverskiold, and modified Kessler suture methods. The repaired tendons were subjected to mechanical testing in an Instron tensile machine to determine the 2-mm gap formation force, ultimate strength, elastic modulus, and energy to failure of the sutures. The 2-mm gap formation forces of the sutures were 43.0 N for the Tang, 37.4 N for the cruciate, 25.0 N for the Robertson, 32.3 N for the Silfverskiold, and 21.2 N for the modified Kessler methods. The ultimate strength of the sutures was 53.6 N for the Tang, 46.3 N for the cruciate, 41.6 N for the Robertson, 41.0 N for the Silfverskiold, and 24.7 N for the modified Kessler methods. Statistically, the gap formation force and ultimate strength were the highest in the Tang, higher in the cruciate, and the lowest for the Robertson and the modified Kessler methods. The elastic modulus of the repaired tendons, as represented by the linear slope of the force-displacement curve, was also statistically the largest in the Tang, larger in the cruciate, and lowest for the Robertson and modified Kessler methods. Energy to failure was statistically the largest in the Tang, higher in the cruciate, lower in the Silfverskiold and the Robertson, and the lowest for the modified Kessler methods. It was concluded that significant differences exist in mechanical properties of the newly developed tendon suture methods. Among the methods for tendon repair that were tested, the Tang and the cruciate sutures were the best candidates for flexor tendon repair in the hand with postoperative active mobilization because of their superior tensile strength, elastic properties, energy to failure, and reasonable operation time.

Carpal instability associated with fracture of the distal radius. Incidence, influencing factors and pathomechanics.

134 fractures of the distal radius in 132 patients are reviewed to determine the incidence and influencing factors of coexisting carpal in stability. By measurement and analysis of the changes in carpal angles and joint spaces, carpal instability was discovered in 41 fractures, an incidence of 30.6%. Six patterns of instability were observed, including dorsal intercalated segmental instability (DISI), scapholunate dissociation, dorsal and palmar translocations, volar intercalated segmental instability (VISI) and ulnar carpal translocation. Accompanying carpal instability was more often seen in elderly patients. To a certain extent, the patterns of instability were related to the type of fracture and palmar tilt angle (PTA) values. DISI was often seen in fractures with PTA smaller than -15 degrees, while scapholunate dissociation was seen in fractures with PTA between -5 degrees and -20 degrees. The possible pathomechanics of the accompanying carpal instability were deduced based on the kinematics and influencing factors indicated in this study.

Subdivision of flexor tendon "no man's land" and different treatment methods in each sub-zone. A preliminary report.

"No man's land" of the flexor tendon system is divided into 4 subdivisions based on our anatomical study. Clinically, a total of 72 flexor tendon injuries in "no man's land" were repaired during the primary and delayed primary stages. Different treatments of flexor tendons, sheath, vincula and postoperative exercises were used according to the degree of injury and anatomical and functional characteristics of each subdivision. The multiple intratendinous suture method, autogenous sheath graft and vincular repair were designed and attempted preliminarily in clinical practice. In 80.4% of the cases, excellent or good results were achieved. Comparison of treatment results in each sub-zone reveals that the IIc sub-zone is the most difficult area for satisfactory functional recovery in "no man's land". The significance of the subdivision of Bunnell's "no man's land" is discussed, and the preoperative assessment method of noting the extent of injury and selection of the treatment method for each sub-zone are presented in this paper. We believe that primary or delayed primary repair can restore good function to the repaired tendons. The effective way of enhancing treatment results of the tendon injury is to apply comprehensive treatment according to the extent of injury to the intrinsic healing capacity of the flexor digitorum profundus tendon.

Surgical management of the tendon sheath at different repair stages. Biomechanical and morphological evaluations of direct sheath closure, partial sheath excision, and interposing sheath grafting.

The effects of direct sheath closure, partial sheath excision, and interposing sheath grafting at different repair stages were evaluated in the chicken model. Primary repair was done after sheath incision and tendon transection, and delayed primary repair was done 4 days after sheath and tendon injuries. The sheath grafting was accomplished by interposing a patch of sheath between the longitudinal incision of the plantar sheath. Six weeks later, biomechanical tests for measuring gliding excursions of the repaired tendons, morphological examinations of the extent of adhesions, and histological observations of the closed sheath or the grafted sheath were carried out. At the primary repair stage, the sheath interposing graft achieved more significant gliding excursion than the groups of direct sheath closure (P less than 0.01) and partial sheath excision (P less than 0.001), and no difference was found between the latter two groups (P greater than 0.05). At the delayed primary repair stage, the sheath interposing graft group was better than the partial excision graft group (P less than 0.05), and the partial excision group was better than the direct closure group (P less than 0.001). The sheath graft and sheath closure at the primary repair stage prevented adhesion formation, but the directly closed sheath did not keep intact after the delayed primary repair and extensive adhesion occurred. In this paper, the importance of volume of the repaired sheath tunnel and possible reasons for results of the delayed primary sheath closure were discussed and the management of flexor tendon sheath for different injuries at different repair stages was suggested.

Flexor tendon repair in zone 2C.

A randomized prospective clinical study was carried out in 33 patients (37 fingers) with lacerations of both FDS and FDP tendons in the area covered by the A2 pulley, that is, zone 2C in Tang's subdivision of no man's land. Both lacerated tendons were repaired in 19 fingers and repair of only FDP with regional excision of FDS were performed in 18 fingers. Follow-up of average 12 months revealed that there was no significant difference in the end results evaluated according to the TAM system. The average TAM was 204 degrees in the fingers with suture of FDP only and 187 degrees in those with suture of both tendons. The fingers with suture of both tendons showed a higher rate of re-operation due to adhesions or rupture of repair. This study suggests that it is better to repair only FDP with regional excision of FDS when both tendons are injured in zone 2C.