Aged Tendons Exhibit Altered Mechanisms of Strain-Dependent Extracellular Matrix Remodeling.

Aging is a primary risk factor for degenerative tendon injuries, yet the etiology and progression of this degeneration are poorly understood. While aged tendons have innate cellular differences that support a reduced ability to maintain mechanical tissue homeostasis, the response of aged tendons to altered levels of mechanical loading has not yet been studied. To address this question, we subjected young and aged murine flexor tendon explants to various levels of in vitro tensile strain. We first compared the effect of static and cyclic strain on matrix remodeling in young tendons, finding that cyclic strain is optimal for studying remodeling in vitro. We then investigated the remodeling response of young and aged tendon explants after 7 days of varied mechanical stimulus (stress deprivation, 1%, 3%, 5%, or 7% cyclic strain) via assessment of tissue composition, biosynthetic capacity, and degradation profiles. We hypothesized that aged tendons would show muted adaptive responses to changes in tensile strain and exhibit a shifted mechanical setpoint, at which the remodeling balance is optimal. Interestingly, we found that 1% cyclic strain best maintains native physiology while promoting extracellular matrix (ECM) turnover for both age groups. However, aged tendons display fewer strain-dependent changes, suggesting a reduced ability to adapt to altered levels of mechanical loading. This work has a significant impact on understanding the regulation of tissue homeostasis in aged tendons, which can inform clinical rehabilitation strategies for treating elderly patients.

Effect of platelet-rich plasma in Achilles tendon allograft in rabbits.

BACKGROUND: Achilles tendon is composed of dense connective tissue and is one of the largest tendons in the body. In veterinary medicine, acute ruptures are associated with impact injury or sharp trauma. Healing of the ruptured tendon is challenging because of poor blood and nerve supply as well as the residual cell population. Platelet-rich plasma (PRP) contains numerous bioactive agents and growth factors and has been utilized to promote healing in bone, soft tissue, and tendons. OBJECTIVE: The purpose of this study was to evaluate the healing effect of PRP injected into the surrounding fascia of the Achilles tendon after allograft in rabbits. METHODS: Donor rabbits (n = 8) were anesthetized and 16 lateral gastrocnemius tendons were fully transected bilaterally. Transected tendons were decellularized and stored at -80°C prior to allograft. The allograft was placed on the partially transected medial gastrocnemius tendon in the left hindlimb of 16 rabbits. The allograft PRP group (n = 8) had 0.3 mL of PRP administered in the tendon and the allograft control group (n = 8) did not receive any treatment. After 8 weeks, rabbits were euthanatized and allograft tendons were transected for macroscopic, biomechanical, and histological assessment. RESULTS: The allograft PRP group exhibited superior macroscopic assessment scores, greater tensile strength, and a histologically enhanced healing process compared to those in the allograft control group. CONCLUSIONS: Our results suggest administration of PRP on an allograft tendon has a positive effect on the healing process in a ruptured Achilles tendon.

Acute Patellar Tendon Ruptures: An Update on Management.

Patellar tendon ruptures can be debilitating injuries. When incomplete, partial tears can be managed nonsurgically with immobilization and progressive rehabilitation. Although complete ruptures remain a relatively uncommon injury, they portend a high level of morbidity. Ruptures typically result from an acute mechanical overload to the extensor mechanism, such as with forced quadriceps contraction and knee flexion. However, chronically degenerated tendons are also predisposed to failure from low-energy injuries. Diagnosis can often be made clinically with recognition of a palpable defect to the tendon, localized patellar tendon tenderness, and inability to actively extend the knee. Diagnosis and surgical planning can be established with radiograph, ultrasonography, or magnetic resonance imaging. Surgical repair is the mainstay of treatment, and there have been many recent advances in repair technique, optimal reconstruction strategies, and supplemental fixation. Time to surgery for complete tears remains the most important prognosticator for success. Direct primary repair can be completed with transosseous tunnels, suture anchor repair, or end-to-end repair. Tendon reconstruction can be achieved with or without mechanical or biologic augments. Rehabilitation programs vary in specifics, but return to sport can be expected by 6 months postoperatively.

Establishment of a Mouse Degenerative Model of Patellar Tendinopathy with Upregulation of Inflammation.

There is no mouse model of patellar tendinopathy. This study aimed to establish a mouse inflammatory and degenerative patellar tendon injury model, which will facilitate research on patellar tendinopathy using advanced molecular tools including transgenic models. Collagenase at different doses (low dose (LD), medium dose (MD), high dose (HD)) or saline was injected over the mouse patellar tendon. At weeks 1, 2, 4, and 8 post-injection, the tendons were harvested for histology and further examined by micro-computed tomography (microCT) imaging at week 8. The optimal dose group and the saline group were further evaluated by immunohistochemical staining, gait pattern, and biomechanical properties. The histopathological score increased dose-dependently post-collagenase injection. Ectopic mineralization was observed and increased with collagenase dose. The LD group was selected for further analysis. The expression of IL-10, TNF-α, and MMP-1 significantly increased post-injection. The changes of limb idleness index (ΔLII) compared to preinjury state were significantly higher, while the ultimate load, stiffness, ultimate stress, and maximum Young's modulus were significantly lower in the LD group compared to the saline group. A mouse inflammatory degenerative model of patellar tendon injury resembling tendinopathy was established as indicated by the dose-dependent increase in tendon histopathology, ectopic calcification, decrease in biomechanical properties, and pain-associated gait changes.

Engineering Tendon Assembloids to Probe Cellular Crosstalk in Disease and Repair.

Tendons enable locomotion by transferring muscle forces to bones. They rely on a tough tendon core comprising collagen fibers and stromal cell populations. This load-bearing core is encompassed, nourished, and repaired by a synovial-like tissue layer comprising the extrinsic tendon compartment. Despite this sophisticated design, tendon injuries are common, and clinical treatment still relies on physiotherapy and surgery. The limitations of available experimental model systems have slowed the development of novel disease-modifying treatments and relapse-preventing clinical regimes. In vivo human studies are limited to comparing healthy tendons to end-stage diseased or ruptured tissues sampled during repair surgery and do not allow the longitudinal study of the underlying tendon disease. In vivo animal models also present important limits regarding opaque physiological complexity, the ethical burden on the animals, and large economic costs associated with their use. Further, in vivo animal models are poorly suited to systematic probing of drugs and multicellular, multi-tissue interaction pathways. Simpler in vitro model systems have also fallen short. One major reason is a failure to adequately replicate the three-dimensional mechanical loading necessary to meaningfully study tendon cells and their function. The new 3D model system presented here alleviates some of these issues by exploiting murine tail tendon core explants. Importantly, these explants are easily accessible in large numbers from a single mouse, retain 3D in situ loading patterns at the cellular level, and feature an in vivo-like extracellular matrix. In this protocol, step-by-step instructions are given on how to augment tendon core explants with collagen hydrogels laden with muscle-derived endothelial cells, tendon-derived fibroblasts, and bone marrow-derived macrophages to substitute disease- and injury-activated cell populations within the extrinsic tendon compartment. It is demonstrated how the resulting tendon assembloids can be challenged mechanically or through defined microenvironmental stimuli to investigate emerging multicellular crosstalk during disease and injury.

Modified gastro-soleus turn-down flap for chronic or neglected achilles tendon ruptures.

BACKGROUND: Achilles' tendon chronic rupture is a common entity that is usually misdiagnosed or mistreated. Hence, she was presented to us later or with complications affecting her gait. Surgical resection is needed to either bridge the gap or reinforce the strength of the tendon repair. OBJECTIVES: Our study's goal was to assess the clinical results of repairing chronic Achilles' tendon lesions employing the middle segment of the proximal portion of the tendon (gastro-soleus), as a turn-down flap. METHODS: Our prospective interventional single arm study included 18 patients with chronic Achilles' tendon rupture attending at Al-Azhar university hospitals in Cairo, Egypt from May 2020 to April 2023. Diagnosis of the patients was confirmed by radiographic and clinical investigations. They were all treated with the same open reconstruction procedure using a modified GSF. The average follow-up was 12 months. The results of this study were assessed by the Achilles tendon rupture score (ATRS), American Orthopedic Foot and Ankle Society (AOFAS) score, and capacity to perform repeated heel raises on the affected side. RESULTS: The mean operative time was 72.77 min. The median (IQR) time of reconstruction was 10 (8-12) after the injury. The median (IQR) length of flab was 4.5 (4.3-5) 9 (Table 2). No intraoperative complications occurred. The typical follow-up period was 12 months (6-18 months). In terms of the ATRS, we found a significant reduction from 82.8 ± 3 preoperatively to 20.8 ± 6.7 at 12 months postoperatively (P value = 0.001). As regards the AOFAS score, it was increased from 49.5 ± 10 preoperatively to 83.8 ± 8.5 12 months postoperatively (P = 0.001). In terms of the post operative complications, there was no re-rupture. Two patients experienced superficial wound infection which improved with daily dressing and antibiotics. Additionally, two patients had slight ankle stiffness four months after the operation, which improved after programmed rehabilitation at the sixth month. CONCLUSION: The modified GSTF is a simple, safe, well-tolerated and effective method of treatment with excellent functional results and greater patient content.

Studying Edema Formation After Release of the Infraspinatus Muscle as an Experimental Model of Rotator Cuff Lesions in Sheep: A Histological Analysis.

BACKGROUND: Muscle edema formation and inflammatory processes are early manifestations of acute rotator cuff lesions in sheep. Histological analysis of affected muscles revealed edema formation, inflammatory changes, and muscle tissue disruption in MRs. HYPOTHESIS: Edema contributes to inflammatory reactions and early muscle fiber degeneration before the onset of fatty infiltration. STUDY DESIGN: Controlled laboratory study. METHODS: Osteotomy of the greater tuberosity, including the insertion of the infraspinatus tendon, was performed on 14 sheep. These experimental animal models were divided into 2 groups: a nontrauma group with surgical muscle release alone (7 sheep) and a trauma group with standardized application of additional trauma to the musculotendinous unit (7 sheep). Excisional biopsy specimens of the infraspinatus muscle were taken at 0, 3, and 4 weeks. RESULTS: Edema formation was histologically demonstrated in both groups and peaked at 3 weeks. At 3 weeks, signs of muscle fiber degeneration were observed. At 4 weeks, ingrowth of loose alveolar and fibrotic tissue between fibers was detected. Fatty tissue was absent. The diameter of muscle fibers increased in both groups, albeit to a lesser degree in the trauma group, and practically normalized at 4 weeks. Immunohistology revealed an increase in macrophage types 1 and 2, as well as inflammatory mediators such as prostaglandin E2 and nuclear factor kappa-light-chain-enhancer of activated B cells. CONCLUSION: Early muscle edema and concomitant inflammation precede muscle fiber degeneration and fibrosis. Edema formation results from tendon release alone and is only slightly intensified by additional trauma. CLINICAL RELEVANCE: This study illustrates that early edema formation and inflammation elicit muscle fiber degeneration that precedes fatty infiltration. Should this phenomenon be applicable to human traumatic rotator cuff tears, then surgery should be performed as soon as possible, ideally within the first 21 days after injury.

Flexor Injury Rehabilitation Splint Trial (FIRST): protocol for a pragmatic randomised controlled trial comparing three splints for finger flexor tendon repairs.

BACKGROUND: Without surgical repair, flexor tendon injuries do not heal and patients' ability to bend fingers and grip objects is impaired. However, flexor tendon repair surgery also requires optimal rehabilitation. There are currently three custom-made splints used in the rehabilitation of zone I/II flexor tendon repairs, each with different assumed harm/benefit profiles: the dorsal forearm and hand-based splint (long), the Manchester short splint (short), and the relative motion flexion splint (mini). There is, however, no robust evidence as to which splint, if any, is most clinical or cost effective. The Flexor Injury Rehabilitation Splint Trial (FIRST) was designed to address this evidence gap. METHODS: FIRST is a parallel group, superiority, analyst-blind, multi-centre, individual participant-randomised controlled trial. Participants will be assigned 1:1:1 to receive either the long, short, or mini splint. We aim to recruit 429 participants undergoing rehabilitation following zone I/II flexor tendon repair surgery. Potential participants will initially be identified prior to surgery, in NHS hand clinics across the UK, and consented and randomised at their splint fitting appointment post-surgery. The primary outcome will be the mean post-randomisation score on the patient-reported wrist and hand evaluation measure (PRWHE), assessed at 6, 12, 26, and 52 weeks post randomisation. Secondary outcome measures include blinded grip strength and active range of movement (AROM) assessments, adverse events, adherence to the splinting protocol (measured via temperature sensors inserted into the splints), quality of life assessment, and further patient-reported outcomes. An economic evaluation will assess the cost-effectiveness of each splint, and a qualitative sub-study will evaluate participants' preferences for, and experiences of wearing, the splints. Furthermore, a mediation analysis will determine the relationship between patient preferences, splint adherence, and splint effectiveness. DISCUSSION: FIRST will compare the three splints with respect to clinical efficacy, complications, quality of life and cost-effectiveness. FIRST is a pragmatic trial which will recruit from 26 NHS sites to allow findings to be generalisable to current clinical practice in the UK. It will also provide significant insights into patient experiences of splint wear and how adherence to splinting may impact outcomes. TRIAL REGISTRATION: ISRCTN: 10236011.

Mild untreated hypercholesterolaemia affects mechanical properties of the Achilles tendon but not gastrocnemius muscle.

Tendon xanthoma and altered mechanical properties have been demonstrated in people with familial hypercholesterolaemia. However, it is unclear whether mild, untreated hypercholesterolaemia alters musculotendinous mechanical properties and muscle architecture. We conducted a case-control study of adults aged 50 years and over, without lower limb injury or history of statin medication. Based on fasting low-density lipoprotein (LDL) cholesterol levels, 6 participants had borderline high LDL (>3.33 mmol/L) and 6 had optimal LDL cholesterol (<2.56 mmol/L). Using shear wave elastography, shear wave velocity (SWV) of the Achilles tendon and gastrocnemius medialis muscle (a proxy for stiffness), along with muscle fascicle length and pennation angle were measured under four passive tensile loads (0, 0.5, 1.0, 1.5 kg) applied via a pulley system. Differences between groups were found for tendon SWV but not muscle SWV, fascicle length or pennation angle. Participants with hypercholesterolaemia showed greater SWV (mean difference, 95 % CI: 2.4 m/s, 0.9 to 4.0, P = 0.024) compared to the control group across all loads. These findings suggest that adults with mild hypercholesterolaemia have increased tendon stiffness under low passive loads, while muscle was not affected. Future research is needed to confirm findings in a larger cohort and explore the impact of hypercholesterolaemia on tendon fatigue injury and tendinopathy.

Effects of evidence-based nursing care interventions on wound pain and wound complications following surgery for finger tendon injury.

We conducted this study aimed to examine the impact of evidence-based nursing interventions on postoperative wound pain and complications after surgery for finger tendon injury. A total of 86 patients treated for finger tendon injuries at our hospital from January 2021 to October 2023 were selected and randomly divided into an experimental group and a control group. The control group received conventional nursing care, while the experimental group received evidence-based nursing interventions. The study compared the postoperative wound pain intensity, incidence of complications and patient satisfaction with nursing care between the two groups. The analysis revealed that compared with conventional care, evidence-based nursing interventions significantly reduced the level of wound pain (p = 0.034) and the incidence of complications (4.65% vs. 18.60%, p = 0.043). It also increased patient satisfaction with the nursing care (97.67% vs. 83.72%, p = 0.026). The study indicates that the application of evidence-based nursing interventions for patients with finger tendon injuries can reduce postoperative wound pain, decrease the incidence of complications and enhance patient satisfaction with nursing care.

A Combined Treatment of BMP2 and Soluble VEGFR1 for the Enhancement of Tendon-Bone Healing by Regulating Injury-Activated Skeletal Stem Cell Lineage.

BACKGROUND: Bone morphogenetic protein 2 (BMP2) is an appealing osteogenic and chondrogenic growth factor for promoting tendon-bone healing. Recently, it has been reported that soluble vascular endothelial growth factor (VEGF) receptor 1 (sVEGFR1) (a VEGF receptor antagonist) could enhance BMP2-induced bone repair and cartilage regeneration; thus, their combined application may represent a promising treatment to improve tendon-bone healing. Moreover, BMP2 could stimulate skeletal stem cell (SSC) expansion and formation, which is responsible for wounded tendon-bone interface repair. However, whether the codelivery of BMP2 and sVEGFR1 increases tendon enthesis injury-activated SSCs better than does BMP2 alone needs further research. PURPOSE: To study the effect of BMP2 combined with sVEGFR1 on tendon-bone healing and injury-activated SSC lineage. STUDY DESIGN: Controlled laboratory study. METHODS: A total of 128 C57BL/6 mice that underwent unilateral supraspinatus tendon detachment and repair were randomly assigned to 4 groups: (1) untreated control group; (2) hydrogel group, which received a local injection of the blank hydrogel at the injured site; (3) BMP2 group, which received an injection of hydrogel with BMP2; and (4) BMP2 with sVEGFR1 group, which received an injection of hydrogel with BMP2 and sVEGFR1. Histology, micro-computed tomography, and biomechanical tests were conducted to evaluate tendon-bone healing at 4 and 8 weeks after surgery. In addition, flow cytometry was performed to detect the proportion of SSCs and their downstream differentiated subtypes, including bone, cartilage, and stromal progenitors; osteoprogenitors; and pro-chondrogenic progenitors within supraspinatus tendon enthesis at 1 week postoperatively. RESULTS: The repaired interface in BMP2 with sVEGFR1 group showed a significantly improved collagen fiber continuity, increased fibrocartilage, greater newly formed bone, and elevated mechanical properties compared with the other 3 groups. There were more SSCs; bone, cartilage, and stromal progenitors; osteoprogenitors; and pro-chondrogenic progenitors in the BMP2 with sVEGFR1 group than that in the other groups. CONCLUSION: Our study suggests that the combined delivery of BMP2 and sVEGFR1 could promote tendon-bone healing and stimulate the expansion of SSCs and their downstream progeny within the injured tendon-bone interface. CLINICAL RELEVANCE: Combining BMP2 with sVEGFR1 may be a good clinical treatment for wounded tendon enthesis healing.

A Novel Tendon Injury Model, Induced by Collagenase Administration Combined with a Thermo-Responsive Hydrogel in Rats, Reproduces the Pathogenesis of Human Degenerative Tendinopathy.

Patellar tendinopathy is a common clinical problem, but its underlying pathophysiology remains poorly understood, primarily due to the absence of a representative experimental model. The most widely used method to generate such a model is collagenase injection, although this method possesses limitations. We developed an optimized rat model of patellar tendinopathy via the ultrasound-guided injection of collagenase mixed with a thermo-responsive Pluronic hydrogel into the patellar tendon of sixty male Wistar rats. All analyses were carried out at 3, 7, 14, 30, and 60 days post-injury. We confirmed that our rat model reproduced the pathophysiology observed in human patients through analyses of ultrasonography, histology, immunofluorescence, and biomechanical parameters. Tendons that were injured by the injection of the collagenase-Pluronic mixture exhibited a significant increase in the cross-sectional area (p < 0.01), a high degree of tissue disorganization and hypercellularity, significantly strong neovascularization (p < 0.01), important changes in the levels of types I and III collagen expression, and the organization and presence of intra-tendinous calcifications. Decreases in the maximum rupture force and stiffness were also observed. These results demonstrate that our model replicates the key features observed in human patellar tendinopathy. Collagenase is evenly distributed, as the Pluronic hydrogel prevents its leakage and thus, damage to surrounding tissues. Therefore, this model is valuable for testing new treatments for patellar tendinopathy.

Surgical management of chronic Achilles tendon rupture: evidence-based guidelines.

BACKGROUND: Chronic Achilles tendon ruptures (CATR) often require surgical intervention to restore function. Despite numerous treatment modalities available, the optimal management strategy remains controversial given the limited high-quality evidence available. This article aims to provide evidence-based guidelines for the surgical management of CATR through a comprehensive systematic review of the available data. The consensus reached by synthesizing the findings will assist clinicians in making informed decisions and improving patient outcomes. METHODS: A group of 9 foot surgeons in three continents was consulted to gather their expertise on guidelines regarding the surgical management of CATR. Following the proposal of 9 clinical topics, a thorough and comprehensive search of relevant literature published since 1980 was conducted for each topic using electronic databases, including PubMed, MEDLINE, and Cochrane Library, to identify relevant studies published until 1 October 2023. All authors collaborated in drafting, discussing, and finalizing the recommendations and statements. The recommendations were then categorized into two grades: grade a (strong) and grade b (weak), following the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) concept. Additionally, feedback from 21 external specialists, who were independent from the authors, was taken into account to further refine and finalize the clinical guidelines. RESULTS: Nine statements and guidelines were completed regarding surgical indications, surgical strategies, and postoperative rehabilitation protocol. CONCLUSION: Based on the findings of the systematic review, this guideline provides recommendations for the surgical management of CATR. We are confident that this guideline will serve as a valuable resource for physicians when making decisions regarding the surgical treatment of patients with CATR.

Endoscopic peroneus brevis tendon transfer for chronic ruptures of the Achilles tendon: surgical technique.

Chronic Achilles tendon rupture is usually defined as a rupture diagnosed 4-6 weeks after injury. The management of chronic Achilles tendon rupture (CATR) is a topic of hot debate, and no consensus has been achieved. Surgical management of CATR is recommended. Several approaches, techniques, and grafts have been described. Open techniques carry a high risk of wound breakdown, infection, and necessitate long rehabilitation times. Surgical techniques with smaller incisions to reduce the risk of scar fibrosis, pain, and infection are becoming common. The ipsilateral tendon of the hallux flexor longus and the peroneus brevis is commonly used. Endoscopic transfer of the peroneus brevis tendon is an innovative alternative to other procedures, with comparable results of other autografts even in elite athletes. The tendon of the peroneus brevis is harvested by tendoscopy before performing a calcaneal tendon endoscopy and fixing the graft in a calcaneal tunnel using an interference screw. After surgery, an anterior splint is placed for 3 weeks with immediate forefoot weight bearing. The rehabilitation starts on the 15th postoperative day.

Advancements in 3D-printed artificial tendon.

Millions of people have been reported with tendon injuries each year. Unfortunately, Tendon injuries are increasing rapidly due to heavy exercise and a highly aging population. In addition, the introduction of 3D-printing technology in the area of tendon repair and replacement has resolved numerous issues and significantly improved the quality of artificial tendons. This advancement has also enabled us to explore and identify the most effective combinations of biomaterials that can be utilized in this field. This review discusses the recent development of the 3D-printed artificial tendon; where recently, some research investigated the most suitable pore sizes, diameter, and strength for scaffolds to have high tendon cells ingrowth and proliferation, giving a better understanding of the effects of densities and structure patterns on tendon's mechanical properties. In addition, it presents the divergence between 3D-printed tendons and other tissue and how the different 3D-printing techniques and models participated in this development.

Correlation between vascular endothelial growth factor A gene polymorphisms and tendon and ligament injury risk: a systematic review and meta-analysis.

BACKGROUND: Relevant evidence suggests that angiogenic factors contribute significantly to fibril matrix reconstruction following physical injuries to tendon ligaments. Vascular endothelial growth factor A (VEGFA), with its potent angiogenic effect, has been studied extensively, and its functional polymorphisms, including rs699947, rs1570360, and rs2010963, have been the focus of numerous investigations. Some scholars have explored the association between gene polymorphisms in the VEGFA and the risk of tendon ligament injury, but the findings are not entirely consistent. OBJECTIVES: The purpose of this study was to investigate the association between rs699947, rs1570360, and rs2010963 gene polymorphisms in VEGFA and the risk of tendon and ligament injuries. METHODS: After including articles about the association of VEGFA rs699947, rs1570360, and rs2010963 polymorphisms with tendon and ligament injuries according to the search strategy, we assessed their quality and conducted meta-analyses to examine the link between these polymorphisms and the risk of tendon and ligament injuries using odds ratios and 95% confidence intervals. RESULTS: Of 86 related articles, six were included in the meta-analysis. Some of these suggest an association between VEGFA rs2010963 and the risk of tendon and ligament injury in the population, with the specific C allele being one of the adverse factors for knee injury. Some studies suggest that VEGFA rs699947 and VEGFA rs1570360 single-nucleotide polymorphisms are associated with anterior cruciate ligament rupture. The risk of non-contact anterior cruciate ligament rupture is nearly doubled in individuals with the rs699947 CC genotype compared to the control group. Our analysis did not find any significant relationship between VEGFA gene polymorphisms (rs699947, rs1570360, and rs2010963) and the chance of tendon and ligament injury without consideration of race. However, the European population reveals that the CC genotype of VEGFA rs699947 can result in a greater risk of tendon and ligament injury, whereas the AG genotype for rs1570360 provides some protection. Additionally, rs2010963 was significantly associated with tendon and ligament injury; individuals with the C allele and the CC genotype had higher risk. False-positive report probability confirmed the high credibility of our results. CONCLUSION: Overall, this study found no significant association between VEGFA rs699947, rs1570360, and rs2010963 polymorphisms and the risk of tendon ligament injury. However, in subgroup analysis, some genotypes of VEGFA rs699947, rs1570360, and rs2010963 were found to increase the risk of tendon ligament injury in European populations.

Management of Checkrein Deformity.

Checkrein deformity is characterized by the dynamic status of the hallux, in which flexion deformity is aggravated by ankle dorsiflexion and relieved by ankle plantarflexion. In most cases, a checkrein deformity occurs secondary to trauma or following surgery. It has been suggested that the flexor hallucis longus tendon tethers or entraps scar tissue or fracture sites. Improvement with conservative treatment is difficult once the deformity has already become entrenched, and surgical management is usually required in severe cases. Various surgical options are available for the correction of checkrein deformities. It includes a simple release of adhesion at the fracture site; lengthening of the flexor hallucis longus by Z-plasty at the fracture site combined with the release of adhesion; lengthening of the flexor hallucis longus by Z-plasty at the midfoot, retromalleolar, or tarsal tunnel area; and flexor hallucis longus tenotomy with interphalangeal arthrodesis for recurrent cases. This review aimed to summarize the overall etiology, relevant anatomy, diagnosis, and treatment of checkrein deformities described in the literature.

Surgical treatment of distal hamstring tendon injuries yield a higher return-to-sports rate: A systematic review.

PURPOSE: The purpose of this study is to compare the patient-reported outcomes and return to sports of the conservative and surgical treatment of distal hamstring tendon injuries. METHODS: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, two reviewers searched PubMed, Scopus and Virtual Health Library databases in January 2023. Clinical studies evaluating conservative or surgical management outcomes of distal hamstring tendon injuries were considered eligible for this systematic review if predefined criteria were fulfilled: (1) published in English or Spanish; (2) evaluated any of the following: patient-reported outcomes, return-to-sports rate (RTS-R) or return-to-sports time (RTS-T). Data were presented in tables using absolute values from individual studies and derived pooled percentages. RESULTS: Eighteen studies were included for 67 patients and 68 distal hamstring tendon injuries. Initially, 39 patients (58.2%) underwent surgical treatment, whereas 28 (41.8%) were treated conservatively. Among conservative treatment patients, 15 failed and had to be operated on (53.6%), all with distal semitendinosus tendon injuries. Anchor fixation was the technique of choice in 20 lesions (36.4%), tenodesis in 16 (29.1%), tenectomy in 14 (25.5%) and sutures were preferred in five (9%). Thirteen out of 28 patients (46.4%) undergoing initial conservative treatment returned to sports at a mean of 3.6 months (range 1 week to 12 months), in contrast to surgical treatment, in which 36 out of 39 patients (92.3%) returned at a mean of 4.2 months (range 6 weeks to 12 months). Additionally, 14 of 15 patients (93.3%) converted to surgical treatment after failed conservative treatment returned to sports at a mean of 7.6 months after injury. CONCLUSION: Initial surgical treatment of distal hamstring tendon injuries yields a high RTS-R (92.3%) at a mean of 4.2 months. Furthermore, 15 out of 28 patients (53.6%) initially treated conservatively had to be operated on, delaying the RTS-T (mean 7.6 months after injury) without affecting their RTS-R. LEVEL OF EVIDENCE: IV.

Tendon Elongation and Function After Delayed or Standard Loading of Surgically Repaired Achilles Tendon Ruptures: A Randomized Controlled Trial.

BACKGROUND: Achilles tendon ruptures often result in long-term functional deficits despite accelerated (standard) rehabilitation. PURPOSE/HYPOTHESIS: The purpose of this study was to investigate if delayed loading would influence functional, clinical, and structural outcomes of the muscles and tendon 1 year after a surgical repair. It was hypothesized that delaying the loading would reduce the heel-rise height deficit 1 year after Achilles tendon rupture. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: In total, 48 patients with a surgically repaired Achilles tendon rupture were randomized to 2 groups: the standard group received the currently accepted rehabilitation, and the delayed group received the same rehabilitation except that initial loading was delayed by 6 weeks. The primary outcome was the heel-rise height difference between the injured and uninjured sides at 1 year. The secondary outcomes were (1) tendon length measured with magnetic resonance imaging, (2) muscle fascicle length and pennation angle of the gastrocnemius medialis muscle, (3) Doppler activity measured with ultrasonography, (4) Achilles tendon Total Rupture Score (ATRS), and (5) isometric muscle strength. RESULTS: The mean heel-rise height deficits for the standard and delayed groups were -2.2 cm and -2.1 cm, respectively (P = .719). The soleus part of the tendon was already elongated 1 week after surgery in both groups without a between-group difference (side-to-side difference: standard, 16.3 mm; delayed, 17.5 mm; P = .997) and did not change over 52 weeks. The gastrocnemius tendon length was unchanged at 1 week but elongated over time without a between-group difference (side-to-side difference at 52 weeks: standard, 10.5 mm; delayed, 13.0 mm; P = .899). The delayed group had less Doppler activity at 12 weeks (P = .006) and a better ATRS (standard, 60 points; delayed, 72 points; P = .032) at 52 weeks. CONCLUSION: Delayed loading was not superior to standard loading in reducing the heel-rise height difference at 1 year. The data indirectly suggested reduced inflammation in the initial months and a better patient-reported outcome at 1 year in the delayed group. The soleus part of the tendon was already markedly elongated (35%) 1 week after surgery, while the length of the gastrocnemius tendon was unchanged at 1 week but was 6% elongated at 1 year. Together, these data indirectly suggest that the delayed group fared better, although this finding needs to be confirmed in future investigations. REGISTRATION: NCT04263493 (ClinicalTrials.gov identifier).