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BACKGROUND: The association between Patient-Rated Elbow Evaluation: Japanese version (PREE-J) and Japanese Orthopaedic Association-Japan Elbow Society Elbow Function score (JOA-JES score) is unclear. This study evaluated the association between PREE-J and JOA-JES scores. METHODS: The patients with elbow disorders were divided into two groups: Group A (conservative treatment, n = 97) and Group B (surgical treatment, n = 156). The patients were also divided into four disease subgroups according to the JOA-JES classification (rheumatoid arthritis, trauma, sports, and epicondylitis groups), and the association between PREE-J and JOA-JES scores in each disease category was examined. In group B, associations between PREE-J and JOA-JES scores were examined pre-and postoperatively. RESULTS: In group A, there were significant associations between PREE-J and JOA-JES scores. In group B, a strong association between preoperative PREE-J and JOA-JES scores was observed in all disease categories. There was also a significant association between postoperative PREE-J and JOA-JES scores. Additionally, group B showed significant postoperative improvements in PREE-J and JOA-JES scores. CONCLUSIONS: The PREE-J score correlates well with the JOA-JES score and reflects treatment response before and after treatment.
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BACKGROUND: Tendon rupture has been recognized as a complication of distal radius fracture (DRF); however, the clinical outcome of reconstructive surgery for this injury remains unclear. We examined prognostic factors for the outcomes of reconstructive surgery in patients with a tendon rupture after DRF. METHODS: This study was a retrospective review of a case series. Seventy-five consecutive patients were treated at our institution for tendon rupture after DRF. The cohort included 14 males and 61 females with a mean age of 67.7 years at the time of tendon reconstruction. Sixty-four and eighteen tendon ruptures occurred after non-operative management for DRF and palmar locking plate fixation, respectively. Seven ruptured tendons received a free tendon graft from the palmaris longus tendon, and the others underwent tendon transfers. All patients were managed postoperatively by our hand therapy unit according to a controlled active mobilization regime. RESULTS: The mean follow-up period was 28 weeks (range: 12-80 weeks). Patients with extensor tendon ruptures were significantly younger than those with flexor tendon ruptures regardless of the initial DRF treatment. The mean percentage active range of motion of the injured digits relative to normal active motion (%AROM) at the final follow-up was 70% (range: 30-101%) in all patients. The %AROM after flexor tendon reconstruction for patients after non-operative management was significantly inferior to that of other patients. Multiple regression analysis revealed that aging and non-operative management of DRF are independent risk factors for poor %AROM. CONCLUSIONS: This study confirmed that advanced age and non-operative management of DRF were prognostic factors for digital joint motion following surgical reconstruction for tendon rupture. Our results suggest that it may be difficult to achieve good clinical outcomes in elderly patients with tendon ruptures (particularly flexor tendon ruptures) following non-operative management of DRF.
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Procedimientos de Cirugía Plástica , Fracturas del Radio , Traumatismos de los Tendones , Anciano , Femenino , Fijación Interna de Fracturas/métodos , Humanos , Masculino , Fracturas del Radio/complicaciones , Fracturas del Radio/diagnóstico por imagen , Fracturas del Radio/cirugía , Rotura , Traumatismos de los Tendones/etiología , Traumatismos de los Tendones/cirugía , Transferencia Tendinosa/efectos adversos , TendonesRESUMEN
Background The placement of multistrand sutures during flexor tendon repair requires complicated surgical skills; such suturing is difficult. We developed a new, simpler eight-strand suture, which we term the Yoshizu cross-lock. This reduces the numbers of suture passages through the tendons, as well as the numbers of knots. Methods Fourteen porcine flexor tendons were transected and repaired using the Yoshizu cross-lock system; no peripheral sutures were placed. Our system is a modification of the published, exposed cross-lock repair method that employs a 4-0 monofilament nylon two-strand line and two needles. The repaired tendons were subjected to linear, noncyclic load-to-failure tensile testing. The initial gap, the 2-mm gap force, and the ultimate strength were measured. Results The initial gap force was 12.6 ± 5.6 Newtons (N), the 2-mm gap force was 33.9 ± 10.9 N, and the ultimate strength was 70.1 ± 17.0 N. All tendons subjected to Yoshizu cross-lock repair failed due to suture rupture rather than pullout. Conclusions Our biomechanical study revealed that Yoshizu cross-lock repair had sufficient tensile strength but was associated with wide variation in the 2-mm gap load (standard deviation = 10.9 N). This study is clinically relevant, showing that the Yoshizu cross-lock repair combined with peripheral suturing may allow a repaired flexor tendon to withstand the stresses encountered during early active mobilization. This simple eight-strand technique will be particularly useful to surgeons who commonly employ the cross-lock stitch for primary flexor tendon repair following early mobilization.
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Most physiological changes follow a daily cycle in animals because their circadian rhythm is adjusted to and synchronized with sunlight. In particular, the circadian rhythm affects liver functions, including pharmacokinetics and metabolism. The influence of circadian rhythm has not been included in hepatotoxicity assays used in drug discovery and development. In this study, the contribution of circadian rhythm was investigated in acetaminophen-induced hepatotoxicity in mice and primary cultured hepatocytes. Hepatotoxicity was induced via the intraperitoneal administration of acetaminophen to a greater extent at night than during the day in mice. The sensitivity of acetaminophen-induced hepatotoxicity was consistent with the expression levels of acetaminophen-metabolizing enzyme and circadian genes. The host-derived circadian rhythm was still evident in the primary cultured hepatocytes within a day after their isolation from the liver. Primary cultured hepatocytes isolated at night were significantly more sensitive to acetaminophen than those isolated during the day. The sensitivity toward acetaminophen-induced hepatotoxicity depended on the circadian rhythm of the expression of acetaminophen-metabolizing genes and intracellular glutathione levels in primary cultured hepatocytes. These results obtained from cultured cells correspond to those in mice, suggesting that the timing of hepatocyte isolation is important when investigating drug metabolism and toxicity tests in culture.
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Acetaminofén/toxicidad , Separación Celular , Enfermedad Hepática Inducida por Sustancias y Drogas/metabolismo , Ritmo Circadiano , Hepatocitos/efectos de los fármacos , Acetaminofén/administración & dosificación , Animales , Células Cultivadas , Hepatocitos/metabolismo , Inyecciones Intraperitoneales , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Transgénicos , Factores de TiempoRESUMEN
BACKGROUND: There have been few studies regarding primary flexor tendon repair of the thumb following early active mobilization, whereas there have been multiple such studies of the finger. This study examined the outcomes of patients who underwent early active mobilization after primary repair of the flexor pollicis longus tendon. METHODS: This study was a retrospective case series. Between 1993 and 2019, 17 thumbs of 17 consecutive patients with complete flexor pollicis longus tendon lacerations were treated using the Yoshizu #1 technique, followed by early active mobilization. The mean time between injury and primary flexor tendon repair was 2 days. Two thumbs had zone T1 injuries and 15 had zone T2 injuries. Mobilization of the thumb began on the first postoperative day with a combination of active extension and passive and active flexion. The mean follow-up period was 8 months. The percentage of total active motion of the thumb was regarded as the sum of the active motion of the two joints, divided by 140°. Functional outcomes were graded in accordance with the Strickland criteria. RESULTS: Three repair ruptures occurred in thumbs treated by inexperienced surgeons. Excluding tendon ruptures, the mean percentage of total active motion of the thumb was 83%. The mean active flexion of the interphalangeal and metacarpophalangeal joints was 62° and 64°. The mean extension deficit was 8.8° at the interphalangeal joint and 7.5° at the metacarpophalangeal joint. According to Strickland's criteria, repairs to eight thumbs were ranked excellent, three were good, one was fair, and five were poor. CONCLUSIONS: Our results are not inferior to the findings of previous reports regarding early postoperative mobilization after primary flexor pollicis longus tendon repair, in terms of the acquisition of active thumb motion. Poor outcomes result from repair rupture and increased extension deficits of the interphalangeal and metacarpophalangeal joints.
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Traumatismos de los Dedos , Traumatismos de los Tendones , Humanos , Rango del Movimiento Articular , Estudios Retrospectivos , Traumatismos de los Tendones/cirugía , Tendones , Pulgar/cirugíaRESUMEN
Background The standard clinical practice to treat closed ruptures of the flexor digitorum profundus (FDP) tendons includes free tendon grafting; however, it is not suitable when the muscle amplitude of the ruptured FDP is not sufficient. We report outcomes of six patients who underwent flexor digitorum superficialis (FDS) tendon transfer of the ring finger using the wide-awake approach to repair the closed rupture of the FDP tendon of the little finger in zone 3 or 4. Methods The patients were identified by reviewing our institutional billing records from January 2012 to October 2019 for the International Classification of Disease 10 code M66.3 that describes the diagnosis as "spontaneous rupture of flexor tendons." Results The patients comprised two men and four women with an average age of 72.2 years (standard deviation [SD], 8.4 years). All patients were hospitalized after surgery to undergo early active mobilization. The average total active motion at the final evaluation was 201.8° (range: 85-248°). According to Strickland's criteria, outcomes were excellent for two, good for three, and poor for one patient. No patients complained about the ring finger. Conclusion These results suggest that FDS tendon transfer is recommended when the muscle amplitude of the ruptured FDP is insufficient. We believe that the wide-awake approach and early active mobilization may contribute to satisfactory outcomes.
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BACKGROUND: Various surgical methods are used for osteochondritis dissecans of the capitellum; however, we have consistently performed a closed-wedge osteotomy of the lateral humeral condyle since 1983. The purpose of this study is to clarify the long-term results of closed-wedge osteotomy for osteochondritis dissecans of the capitellum. METHODS: Seventy-seven elbows with all lesion types of osteochondritis dissecans of the capitellum were treated with closed-wedge osteotomy. Unstable osteochondral fragments were fixed with a bone graft and bone pegs in combination with osteotomy. The mean age of the patients was 14.0 years. The patients were clinically and radiographically evaluated at a median value of 9.0 years after surgery. RESULTS: The range of elbow motion and standard deviation were increased significantly from 119° ± 22° preoperatively to 131° ± 18° postoperatively (P < .001). The Timmerman and Andrews score were improved significantly from 141 ± 26 points preoperatively to 184 ± 21 points postoperatively (P < .001). The Timmerman and Andrews score and the range of elbow motion at final examination in patients with preoperative osteoarthritic changes were significantly inferior to those in patients without preoperative osteoarthritic changes. Good remodeling of the capitellar lesions was radiographically observed in 53 elbows (69%). In the long-term follow-up evaluation, although 41 elbows (53%) had advanced osteoarthritic changes that were classified as grade II or III, disease progression was controlled in most of these cases. CONCLUSIONS: Good or excellent long-term clinical results were maintained in most of our patients. Closed-wedge osteotomy of the lateral humeral condyle is a useful method that can provide acceptable long-term clinical results.
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Articulación del Codo/fisiopatología , Articulación del Codo/cirugía , Húmero/cirugía , Osteocondritis Disecante/cirugía , Osteotomía/métodos , Adolescente , Trasplante Óseo , Niño , Articulación del Codo/diagnóstico por imagen , Epífisis/cirugía , Femenino , Humanos , Húmero/diagnóstico por imagen , Masculino , Osteoartritis/diagnóstico por imagen , Osteoartritis/etiología , Osteoartritis/fisiopatología , Osteocondritis Disecante/complicaciones , Rango del Movimiento Articular , Estudios Retrospectivos , Factores de Tiempo , Resultado del TratamientoRESUMEN
Opioid-related postoperative nausea and vomiting should not occur following remifentanil administration because of its relatively short time to elimination. However, studies have indicated that the incidence of postoperative nausea and vomiting associated with remifentanil is similar to that with other opioids. Hence, we aimed to determine whether intraoperative remifentanil itself is associated with postoperative nausea and vomiting when postoperative pain is managed without opioid use. In this prospective pilot study, 150 patients who underwent unilateral upper limb surgery under general anesthesia with brachial plexus block were included. Patients in the remifentanil and control groups received 0.5 µg/kg/min remifentanil and saline, respectively. Postoperative pain was managed using a brachial plexus block, non-steroidal anti-inflammatory drugs, and acetaminophen. The presence of postoperative nausea and vomiting within the first 24 h after anesthesia was assessed by an evaluator blinded to patient allocation. Eight patients were excluded from the final analysis, resulting in 72 and 70 patients in the remifentanil and control groups, respectively. Postoperative nausea and vomiting within 24 h after surgery occurred in 11 and 9 patients in the remifentanil and control groups, respectively. These data suggest that remifentanil use only minimally affects the incidence of postoperative nausea and vomiting under sevoflurane anesthesia. UMIN Clinical Trials Registry identification number: UMIN000016110.
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Analgésicos Opioides/administración & dosificación , Dolor Postoperatorio/tratamiento farmacológico , Náusea y Vómito Posoperatorios/epidemiología , Remifentanilo/administración & dosificación , Adulto , Anciano , Anestesia General/métodos , Método Doble Ciego , Femenino , Humanos , Masculino , Persona de Mediana Edad , Proyectos Piloto , Estudios ProspectivosRESUMEN
As the thumb is pronated, primary repair of complex injuries may be more difficult than the repair of other digits. We describe a simple technique that facilitates thumb repair. We insert a Kirschner wire perpendicular to the bone axis in the middle of the proximal phalanx, which ensures adequate exposure of the palmar aspect without the need for thumb position adjustment by an assistant. This technique is particularly useful when inexperienced surgeons perform thumb replantation and primary flexor tendon repair using a multistrand suture technique.
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Delayed union and non-union of distal radial fractures (DRFs) are rare, and there are a few reports of delayed union and nonunion of DRFs after palmar locking plate (PLP) fixation. A 68-year-old female patient presented to our hospital with left-sided wrist pain. Radiographs and computed tomography revealed a displaced DRF and ulnar styloid fracture. We performed open reduction and internal fixation with a PLP for the DRF and tension band wiring for the ulnar styloid fracture. However, bone union was not completed three months after the operation. We initiated low-intensity pulsed ultrasound (LIPUS) to achieve fracture healing. Complete bone union was confirmed radiographically five months after LIPUS. There have been few case reports on the delayed union or nonunion of DRFs after PLP fixation treated with LIPUS. LIPUS might be an effective option for the delayed union of DRFs after PLP fixation.
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Despite medical advances, degloving injury remains one of the most difficult traumatic injuries to treat. The conventional method for treating degloving injury of the hand is reconstruction with a groin flap. However, few reports have described the mid- or long-term functional and aesthetic outcomes after a hand reconstruction with a groin flap. This case report describes a 68-year-old woman with no specific medical history who presented with a severe degloving injury of the right hand, caused by a roller machine. The area of skin loss was covered with a pedicled groin flap that was separated after 3 weeks. Five years after the reconstruction, she had poor functional and aesthetic outcomes. The Japanese Society for Surgery of the Hand version of the Quick Disabilities of the Arm, Shoulder and Hand score was 57.5; the Hand20 score was 60; and the Michigan Hand Outcomes Questionnaire score was 37.5. The static two-point discrimination of the index and middle fingers was more than 15 mm, and Semmes-Weinstein monofilament examination showed that the sensation thresholds of these fingers were purple and blue. The range of motion was 10-degree angle of extension and 60-degree angle of flexion for the metacarpophalangeal joints of the index and middle fingers. Grip strength was 0.0 kg; pulp pinch strength of the index and middle fingers was 1.1 and 0.8 kg, respectively; and side pinch of the index and middle fingers was 0.1 and 0.7 kg, respectively.
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Purpose: Preiser disease is difficult to diagnose and treat because of its unclear pathophysiology. Although both nonsurgical treatment and surgical treatment for Preiser disease have been reported, there is no consensus on the optimal treatment because of its rarity. The purpose of this study was to investigate the relationship between treatment selection and characteristics of patients with Preiser disease. Methods: This single-institution retrospective chart review included nine patients (two men and seven women) with Preiser disease who were treated at our hospital. We divided patients into two groups consisting of elderly (older than 65 years of age) and nonelderly patients. Herbert-Lanzetta classification, presence of dorsal intercalated segment instability (DISI), Watson classification based on plain radiography, Kalainov classification based on magnetic resonance imaging, and treatment modalities were investigated in both groups. Results: In the elderly group, three of five cases were in advanced stages of Preiser disease according to the Herbert-Lanzetta classification. Three wrists had a DISI deformity. Three patients underwent conservative treatment. The two remaining cases classified as Herbert-Lanzetta stage II underwent closing radial wedge osteotomy. In the nonelderly group, three of four cases were in the early stages of Preiser disease according to the Herbert-Lanzetta classification. One wrist had a DISI deformity. Two patients were treated conservatively. The other two patients were surgically treated using closing radial wedge osteotomy in one case and vascularized bone graft from the second metacarpal base in another case, both classified as Herbert-Lanzetta stage II. Conclusions: Most elderly patients with Preiser disease showed concurrent DISI at the time of initial presentation and advanced stage. Most elderly patients underwent nonsurgical treatment. Even when surgical treatment is implemented, our study suggests that the less invasive and optimal treatment is closing radial wedge osteotomy. Type of study/level of evidence: Therapeutic IV.
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Purpose: The placement of multistrand sutures during flexor tendon repair is complex and challenging. We developed a new, simpler, nine-strand suture, which we term the Tajima nines. The Tajima nines repair method is a new odd-numbered strand tendon technique. Methods: Fourteen porcine flexor tendons were transected and repaired using the Tajima nines repair method, without placement of peripheral sutures. This technique is a modification of the Lim and Tsai repair method; it uses a 4-0 monofilament nylon, 3-strand line, and two needles. The repaired tendons were tested for linear, noncyclic, load-to-failure tensile strength. The initial gap, 2-mm gap-formation force, and ultimate strength were measured. Results: The initial gap-formation force was 27.9 ± 7.5 newtons (N), the 2-mm gap-formation force was 39.2 ± 4.7 N, and the ultimate strength was 76.7 ± 17.2 N. Eight, three, and three of the 14 tendons repaired using the Tajima nines method demonstrated failure because of thread breakage, knot failure, and suture pull-out, respectively. Conclusions: This biomechanical study demonstrated that Tajima nines repair was associated with particularly high initial tension at the repair site; there were minor variations in the initial load and 2-mm gap-formation load. Our results suggest that Tajima nines repair with peripheral suturing allows the repaired flexor tendon to tolerate the stresses encountered during early active mobilization. Clinical relevance: This simple nine-strand technique will be particularly useful for inexperienced surgeons who perform early active mobilization after primary flexor tendon repair because the technique is a modification of the Lim and Tsai repair method using a triple strand instead of a double strand.
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Heterodigital vascularized hemijoint transfer can theoretically produce a near normal joint by combining intact joint components from different fingers and maintaining the joint space over the long term. We present herein an extremely rare case of heterodigital vascularized hemijoint transfer with a 42-year follow-up, demonstrating the longevity of this joint reconstruction technique for the restoration of hand function. Our patient's outcome indicates that despite the gradual progression of osteoarthritic changes, good subjective results and maintenance of an active range of motion can be acquired even after a long period. Technical factors such as graft fixation and the congruity of the articular surface may influence the gradual degeneration of joint surfaces.
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CASE: A 71-year-old otherwise healthy man presented with an 8-week history of elbow pain and weakness in both elbow flexion and forearm supination. Magnetic resonance imaging revealed complete rupture of the distal biceps tendon insertion associated with 65 mm of proximal retraction. At 10 weeks after initial injury, the patient underwent a novel reconstruction technique using a periosteal flap from the iliac crest; subsequently, all symptoms resolved. CONCLUSION: Chronic distal biceps tendon injuries can be reconstructed safely and effectively using a periosteal flap from the iliac crest that allows not only rigid but also biological graft attachment.
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Articulación del Codo , Traumatismos de los Tendones , Masculino , Humanos , Anciano , Codo/cirugía , Traumatismos de los Tendones/diagnóstico por imagen , Traumatismos de los Tendones/cirugía , Tendones/cirugía , Músculo Esquelético , Articulación del Codo/diagnóstico por imagen , Articulación del Codo/cirugíaRESUMEN
We assessed the influence of different directions of suture strands using the double Tsuge repair on the resistance to gap formation and mode of failure. In total, 25 porcine flexor digitorum profundus tendons were split into two groups. One group was repaired using a conventional double Tsuge suture created by two bands of looped suture placed longitudinally parallel (parallel method), and the other group was repaired using a new technique comprising two bands of looped suture placed in a crossed fashion in the anterior and posterior half of the tendon (cruciate method). The repaired tendons were subjected to linear, non-cyclic load-to-failure tensile testing. The cruciate method had a significantly higher mean load at a 2-mm gap tensile load (29.7 N [SD, 8.3]) than the parallel method (21.6 N [SD, 4.9]) and failed significantly more often due to suture pull-out. The direction of a core suture and its location within the tendon affect both gap resistance and the mode of failure of repair when using the double Tsuge suture technique, with a cruciate configuration achieving a greater gap resistance than a parallel one.
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Traumatismos de los Tendones , Animales , Porcinos , Traumatismos de los Tendones/cirugía , Resistencia a la Tracción , Fenómenos Biomecánicos , Tendones/cirugía , Suturas , Técnicas de SuturaRESUMEN
BACKGROUND: Ulnar shortening osteotomy using various osteotomy sites, osteotomy methods, and surgical techniques with a variety of implants has been reported, but nonunion rates and the duration of bone healing are not uniform by the authors. The purpose of this study was to investigate the duration of bone healing and nonunion ratio in patients who underwent ulnar shortening osteotomy by a 5-hole nonlocking plate with a simple transverse osteotomy for ulnar impaction syndrome and to determine the correlation between the gap length of the osteotomy site and the duration of bone healing. METHODS: We assessed patients who underwent ulnar shortening osteotomy for ulnar impaction syndrome using a 5-hole nonlocking plate fixation followed by a simple transverse osteotomy between July 2012 and October 2021. This study was a case series study, and the level of evidence was IV. RESULTS: A total of 80 patients were included. The mean age of the patients was 46.7 years, and 46 patients were men. The average bone union period was 41.8 ± 18.7 weeks. The correlation between the gap length of the osteotomy site and the duration of bone union of the osteotomy site was not significant. The nonunion ratio of our method was 2.5%. CONCLUSION: The nonunion rate of our ulnar shortening osteotomy with a simple transverse osteotomy and a 5-hole nonlocking plate was comparable to that in previous reports, but our method required slightly longer periods for bone union. There was no correlation between the gap length of the osteotomy and the duration of bone union. LEVEL OF EVIDENCE: Level IV (Case series).
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The current clinical methods of flexor tendon repair are remarkably different from those used 20 years ago. This article starts with a review of the current methods, followed by presentation of past experience and current status of six eminent hand surgery units from four continents/regions. Many units are using, or are moving toward using, the recent strong (multi-strand) core suture method together with a simpler peripheral suture. Venting of the critical pulleys over less than 2 cm length is safe and favours functional recovery. These repair and recent motion protocols lead to remarkably more reliable repairs, with over 80% good or excellent outcomes achieved rather consistently after Zone 2 repair along with infrequent need of tenolysis. Despite slight variations in repair methods, they all consider general principles and should be followed. Outcomes of Zone 2 repairs are not dissimilar to those in other zones with very low to zero incidence of rupture.
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Traumatismos de los Dedos , Traumatismos de los Tendones , Traumatismos de los Dedos/cirugía , Humanos , Técnicas de Sutura , Suturas , Traumatismos de los Tendones/cirugía , Tendones/cirugíaRESUMEN
The purpose of this study was to compare the outcomes of bridge tendon grafts and end-to-side tendon transfers for treating closed ruptures of the flexor tendons in Zones 3 to 5 of the little finger. We selected the surgical procedure based on the passive distraction amplitude of the proximal part of the ruptured flexor tendon. Eleven patients comprised the bridge tendon graft group and ten patients comprised the end-to-side tendon transfer group. We found no significant between-group differences in the total active motion, percentage of total active motion, functional assessment by the Strickland and Glogovac criteria and grip strength compared with the unaffected hand. We believe that choosing the surgical procedure after determining the passive distraction amplitude of the ruptured tendon can be useful in clinical practice.Level of evidence: III.
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Traumatismos de los Dedos , Traumatismos de los Tendones , Traumatismos de los Dedos/cirugía , Humanos , Rotura/cirugía , Traumatismos de los Tendones/cirugía , Transferencia Tendinosa/métodos , Tendones/cirugíaRESUMEN
The processing of type I procollagen is essential for fibril formation; however, the steps involved remain controversial. We constructed a live cell imaging system by inserting fluorescent proteins into type I pre-procollagen α1. Based on live imaging and immunostaining, the C-propeptide is intracellularly cleaved at the perinuclear region, including the endoplasmic reticulum, and subsequently accumulates at the upside of the cell. The N-propeptide is also intracellularly cleaved, but is transported with the repeating structure domain of collagen into the extracellular region. This system makes it possible to detect relative increases and decreases in collagen secretion in a high-throughput manner by assaying fluorescence in the culture medium, and revealed that the rate-limiting step for collagen secretion occurs after the synthesis of procollagen. In the present study, we identified a defect in procollagen processing in activated hepatic stellate cells, which secrete aberrant collagen fibrils. The results obtained demonstrated the intracellular processing of type I procollagen, and revealed a link between dysfunctional processing and diseases such as hepatic fibrosis.