Subrupture tendon fatigue damage

The mechanical and microstructural bases of tendon fatigue, by which damage accumulates and contributes to degradation, are poorly understood. To investigate the tendon fatigue process, rat flexor digitorum longus tendons were cyclically loaded (1–16 N) until reaching one of three levels of fatigue damage, defined as peak clamp‐to‐clamp strain magnitudes representing key intervals in the fatigue life: i) Low (6.0%–7.0%); ii) Moderate (8.5%–9.5%); and iii) High (11.0%–12.0%). Stiffness, hysteresis, and clamp‐to‐clamp strain were assessed diagnostically (by cyclic loading at 1–8 N) before and after fatigue loading and following an unloaded recovery period to identify mechanical parameters as measures of damage. Results showed that tendon clamp‐to‐clamp strain increased from pre‐ to post‐fatigue loading significantly and progressively with the fatigue damage level (p ≤ 0.010). In contrast, changes in both stiffness and hysteresis were significant only at the High fatigue level (p ≤ 0.043). Correlative microstructural analyses showed that Low level of fatigue was characterized by isolated, transverse patterns of kinked fiber deformations. At higher fatigue levels, tendons exhibited fiber dissociation and localized ruptures of the fibers. Histomorphometric analysis showed that damage area fraction increased significantly with fatigue level (p ≤ 0.048). The current findings characterized the sequential, microstructural events that underlie the tendon fatigue process and indicate that tendon deformation can be used to accurately assess the progression of damage accumulation in tendons. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:264–273, 2009     

Remodeling of murine intrasynovial tendon adhesions following injury: MMP and neotendon gene expression

Tendon injury frequently results in the formation of adhesions that reduce joint range of motion. To study the cellular, molecular, and biomechanical events involved in intrasynovial tendon healing and adhesion formation, we developed a murine flexor tendon healing model in which the flexor digitorum longus (FDL) tendon of C57BL/6 mice was transected and repaired using suture. This model was used to test the hypothesis that murine flexor tendons heal with differential expression of matrix metalloproteases (MMPs), resulting in the formation of scar tissue as well as the subsequent remodeling of scar and adhesions. Healing tendons were evaluated by histology, gene expression via real-time RT-PCR, and in situ hybridization, as well as biomechanical testing to assess the metatarsophalangeal (MTP) joint flexion range of motion (ROM) and the tensile failure properties. Tendons healed with a highly disorganized fibroblastic tissue response that was progressively remodeled through day 35 resulting in a more organized pattern of collagen fibers. Initial repair involved elevated levels of Mmp-9 at day 7, which is associated with catabolism of damaged collagen fibers. High levels of Col3 are consistent with scar tissue, and gradually transition to the expression of Col1. Scleraxis expression peaked at day 7, but the expression was limited to the original tendon adjacent to the injury site, and no expression was present in granulation tissue involved in the repair response. The MTP joint ROM with standardized force on the tendon was decreased on days 14 and 21 compared to day 0, indicating the presence of adhesions. Peak expressions of Mmp-2 and Mmp-14 were observed at day 21, associated with tendon remodeling. At day 28, two genes associated with neotendon formation, Smad8 and Gdf-5, were elevated and an improvement in MTP ROM occurred. Tensile strength of the tendon progressively increased, but by 63 days the repaired tendons had not reached the tensile strength of normal tendon. The murine model of primary tendon repair, described here, provides a novel mechanism to study the tendon healing process, and further enhances the understanding of this process at the molecular, cellular, and biomechanical level. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27: 833–840, 2009     

小切口微创治疗新鲜跟腱断裂

[目的]探讨通过小切口应用跟腱缝合引导器微创治疗新鲜跟腱断裂的临床效果.[方法]2006年3月-2008年3月,通过小切口应用跟腱缝合引导器微创治疗连续的26例新鲜跟腱断裂病人,术后早期功能锻练.男24例,女2例.年龄22～58岁,平均37.6岁.24例获得12～36个月(平均21个月)的随访.采用美国足与踝关节协会(AOFAS)踝与后足功能评分标准进行评分,测量双侧小腿最大周径及跟腱断裂平面的周径,询问恢复工作及伤前体育活动的时间.[结果]无跟腱再断裂、切口表浅或深部感染、皮缘坏死等并发症.腓肠神经支配区皮肤感觉正常.AOFAS 平均得分为97分(86～100分).23例恢复伤前工作与学习,恢复工作时间平均为10周(4～20周).24例均恢复伤前体育活动,恢复伤前体育活动时间平均为20周(18～24周).小腿最大周径伤侧较对侧平均减少0.4 cm(0.2～0.8 cm),跟腱断裂平面周径伤侧较对侧平均增粗0.5 cm(0.3～0.7 cm).[结论]应用跟腱缝合引导器微创修复新鲜跟腱断裂结合早期功能锻练可得到满意的临床效果,可较早恢复伤前状态,有较少的并发症.     

跟腱区动脉血供的三维可视化研究

目的通过数字化技术构建跟腱区动脉血供的三维可视化图像,研究跟腱区的动脉血供。方法新鲜人小腿标本三只,用30％明胶、10％朱砂、10％淀粉按比例配制的灌注液灌注,冷藏后CT扫描获得DICOM格式数据,Mimics 10．01软件处理。结果获得小腿跟腱区皮肤、骨骼、动脉、跟腱的三维可视化图像。结论跟腱区三维可视化图像可为临床提供形态学资料,虚拟手术有助于最佳手术方案的选择。     

创伤性复发性腓骨肌腱脱位的手术治疗

目的研究创伤性复发性腓骨肌腱脱位的手术方法. 方法回顾分析1986年1月～2003年12月手术治疗的21例创伤性复发性腓骨肌腱脱位的病例,所有病例均应用Watson Jones手术. 结果 15例得到随访,随访时间1～15年,平均4.9年.1例因外伤再次脱位,其余14例未再出现脱位,均恢复正常运动或训练,比赛. 结论 Watson Jones手术治疗复发性脱位操作简单,损伤小,效果满意.     

Use of an IL1‐receptor antagonist to prevent the progression of tendinopathy in a rat model

This study evaluated if inhibiting IL1‐β activity with an IL1‐receptor antagonist (IL1‐RA) will prevent pathologic changes commonly seen in tendinopathy. Thirty‐six Sprague–Dawley retired‐breeder rats were divided into three groups having weekly bilateral patellar tendon injections: CON (0.1 ml Saline), CAR (0.1 ml 2% carrageenan), IL1‐RA (0.1 ml 2% CAR plus 0.94 mg of the IL1‐RA, 2.5 mg/kg). Carrageenan was used to establish tendinopathy in two groups due to its ability to develop tendinopathy in prior studies. Animals were euthanized 3 weeks after initial injection. The CAR group demonstrated significantly (p < 0.05) shorter tendon lengths (8.61 ± 0.38 mm) relative to CON (8.94 ± 0.38 mm) that was prevented in the IL1‐RA (9.02 ± 0.30 mm) as well as significantly increased collagenase activity in the CAR (0.061 ± 0.043) compared to CON (0.027 ± 0.015) (p< 0.05). By histological evaluation, the CAR group demonstrated significantly greater inflammation than IL1‐RA, and CON (p < 0.05). CAR showed a trend for increased cross‐sectional area relative to CON that was absent in the IL1‐RA. IL1‐RA can effectively inhibit the development of mechanical, chemical, and histologic changes seen with carrageenan‐induced tendonitis. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:616–622, 2016.     

Surgical approaches to intramedullary nailing of the tibia: Comparative analysis of knee pain and functional outcomes

IntroductionPost-operative knee pain is common following intramedullary nailing of the tibia, regardless of surgical approach, though the exact source is controversial. Historically, the most common surgical approaches position the knee in hyperflexion, including patellar tendon splitting (PTS) and medial parapatellar (MPP). A novel technique, the semi-extended lateral parapatellar approach simplifies patient positioning, fracture reduction, fluoroscopic assessment, and implant insertion. It also avoids violation of the knee joint capsule. However, this approach has not yet been directly compared against the historical standards. We hypothesised that in a comparison of patient outcomes, the semi-extended approach would be associated with decreased knee pain and better function relative to knee hyperflexion approaches.MethodsA trauma patient database from a Level I centre was queried for patients who underwent intramedullary nailing of the tibia between 2009 and 2013. Patients were surveyed for knee pain severity (NRS scale 1 to 10) and location, and completion of the Lysholm Knee Scale (LKS). Data was compared between the semi-extended lateral parapatellar, medial parapatellar, and tendon splitting groups regarding knee pain severity, location, total LKS, and individual knee function scores from the Lysholm questionnaire. Pre-hoc power analysis determined the necessary sample size (n = 34). Post-hoc analysis utilised two-way ANOVA analysis with a significance threshold of p < 0.05.ResultsComparison of knee pain severity between the groups found no significant difference (p = 0.69), with average ratings of: semi-extended (3.26), PTS (3.59), and MPP (3.63). Analysis found no significant differences in total LKS score (p = 0.33), with average sums of: semi-extended (75.97), MPP (77.53), and PTS (81.68). Individual knee function scores from the LKS were similar between the groups, except for limping, with MPP being significantly worse (p = 0.04). There was no significant difference in knee pain location (p = 0.45).ConclusionIn this adequately-powered study, at minimum 1 year follow-up there were no significant differences between the 3 approaches in knee pain severity, location, or overall function. The three were significantly different in post-operative limping, with medial parapatellar having the lowest score. The semi-extended lateral parapatellar approach vastly simplifies many technical aspects of nailing compared to knee hyperflexion approaches, and does not violate the knee joint.     

Spontaneous and simultaneous rupture of both Achilles tendons and pathological fracture of the femur neck in a patient receiving long-term hemodialysis

Spontaneous rupture of the Achilles tendons in hemodialysis patients is a rare complication. The majority of these patients have additional predisposing factors, such as previous use of fluoroquinolone antibiotics or corticosteroids. Spontaneous rupture of bilateral Achilles tendons without any of those predisposing factors is exceptional. In this paper, we report a 43-year-old woman who had been undergoing regular hemodialysis for 16 years. She developed bilateral spontaneous and simultaneous rupture of the Achilles tendons. She also developed pathological fracture of right femur neck 3 years later. Based on previous cases of tendon ruptures in uremic patients and the lack of history for the use of corticosteroids or fluoroquinolones, we believe that secondary hyperparathyroidism is the predisposing factor in this patient.     

腓骨长肌转位修复陈旧性跟腱断裂

陈旧性跟腱断裂手术修复较困难，术后效果与新鲜断裂相比较差，且重建的跟腱由于瘢痕增生而粗大，踝关节活动受限。作者于2000年8月-2003年11月利用腓骨长肌转位重建跟腱术19例，取得满意效果。