Objectives. Recently, the field of tissue engineering has made numerous advances towards achieving artificial tendon substitutes with excellent mechanical and histological properties, and has had some promising experimental results. The purpose of this systematic review is to assess the efficacy of tissue engineering in the treatment of tendon injuries. Methods. We searched MEDLINE, Embase, and the Cochrane Library for the time period 1999 to 2016 for trials investigating tissue engineering used to improve tendon healing in animal models. The studies were screened for inclusion based on randomization, controls, and reported measurable outcomes. The RevMan software package was used for the meta-analysis. Results. A total of 388 references were retrieved and 35 studies were included in this systematic review. The different biomaterials developed were analyzed and we found that they improve the biomechanical and histological characteristics of the repaired tendon. At meta-analysis, despite a high heterogeneity, it revealed a statistically significant effect in favour of the maximum load, the maximum stress, and the Young’s modulus between experimental and control groups. In the forest plot, the diamond was on the right side of the vertical line and did not intersect with the line, favouring experimental groups. Conclusions. This review of the literature demonstrates the heterogeneity in the tendon tissue engineering literature. Several biomaterials have been developed and have been shown to enhance tendon healing and regeneration with improved outcomes. Cite this article: D. González-Quevedo, I. Martínez-Medina, A. Campos, F. Campos, V. Carriel. Tissue engineering strategies for the treatment of tendon injuries: a systematic review and meta-analysis of animal models. Bone Joint Res 2018;7:318–324. DOI: 10.1302/2046-3758.74.BJR-2017-0326

The retear of the rotator cuff (RC) repair is a significant problem. Usually it is the effect of poor quality of the tendon. The aim was to evaluate histologically two types of RC reconstruction with scaffold. We have chosen commercially available scaffold polycaprolactone based poly(urethane urea). Rat model of supraspinatus tendon injury was chosen. There were four study groups: RC tear (no repair) (n=10), RC repair (n=10), RC repair augmented with scaffold (n=10) and RC reconstruction with scaffold interposition between tendon and bone (n=10). The repairs were investigated histologically at 6 and 16 weeks. The results in two groups in which scaffold was used had significantly better scores at 6 weeks comparing to non-scaffold groups (16,4±3, 17,3± 2,8 vs. 12,5±4,4, 13,8±1,4 respectively) and 16 weeks (23±1,9, 22,8±1,6 vs. 13,8±3,3, 14,9± 3,8 respectively). Results in two scaffold groups improved between 6 and 16 weeks. Signs of foreign body reaction against scaffold were not observed. Application of scaffold to strengthen the repair site and bridging of the tendon defect improved healing of the RC repair in animal model at 6 and 16 weeks. The quality of reconstructed tendon improved over time. No such effect was observed in groups without repairs and isolated repairs were performed

We describe a new surgical technique for the treatment of lacerations of the extensor tendon in zone I, which involves a tenodesis using a length of palmaris longus tendon one-quarter of its width. After exposing the dorsal aspect of the distal interphalangeal joint and harvesting the tendon, a 1.5 mm drill bit is passed through the insertion of the extensor tendon into the distal phalanx where it penetrates through the skin of the pulp of the digit. The palmaris longus tendon is threaded through the drill hole from dorsal to ventral and the ventral end is tied in a simple knot and trimmed. The palmaris longus tendon is then sutured to the extensor tendon close to its insertion, and also at the middle of the middle phalanx.

The operation was undertaken on 67 patients: 27 with an acute injury and 40 patients with a chronic mallet deformity. One finger (or the thumb) was involved in each patient. At a mean follow-up of 12 months (6 to 18), 66 patients (98.5%) received excellent or good results according to both the American Society for Surgery of the Hand (ASSH) classification and Miller’s classification.

Tenodesis using palmaris longus tendon after complete division of an extensor tendon in zone 1 is a reliable form of treatment for isolated acute or chronic ruptures.

Flat foot due to rupture of the tibialis posterior tendon has not previously been described in children. We present three young patients who developed unilateral pes planus after old undiagnosed lacerations of the tendon. Transfer of the flexor hallucis longus to the distal stump of the tibialis posterior tendon achieved good results in all three cases.

Objectives

Re-rupture is common after primary flexor tendon repair. Characterization of the biological changes in the ruptured tendon stumps would be helpful, not only to understand the biological responses to the failed tendon repair, but also to investigate if the tendon stumps could be used as a recycling biomaterial for tendon regeneration in the secondary grafting surgery.

Aims

The aim of the study was to analyze the results of primary tendon reinsertion in acute and chronic distal triceps tendon ruptures (DTTRs) in the general population.

Tendon injuries after distal radius fractures Introduction: Tendon injuries after distal radius fractures are a well-documented complication that can occur in fractures managed both operatively and non-operatively. The extensor tendons, in particular the extensor pollicis longus (EPL) tendon, can be damaged and present late after initial management in a cast, or by long prominent screws that penetrate the dorsal cortex and cause attrition. Similarly, a prominent or distally placed volar plate can damage the flexor pollicis longus tendon (FPL). The aim of our study was to evaluate the incidence of tendon injuries associated with distal radius fractures. We conducted a single centre prospective observational study. Patients aged 18–99 who presented with a distal radius fracture between May 2018 to April 2020 were enrolled and followed-up for 24 months. Tendon injuries in the group were prospectively evaluated. Results: 199 patients with distal radius fractures were enrolled. 119 fractures (59.8%) had fixation and 80 (40.2%) were managed incast. In the non-operative group, 2 (2.5%) had EPL ruptures at approximately 4 weeks post injury. There were no extensor tendon ruptures in the operative group. In the operative group, there were 6 (5%) patients that required removal of metalware for FPL irritation. At the time of operation, there were no tendon ruptures noted. Within the operative group we evaluated plate prominence using a previously described classification (Soong et al.). 5 of the 6 patients (83%) with FPL irritation had Grade 3 prominence. The incidence of both flexor and extensor tendon injury in our cohort was 4%, extensor tendon rupture was 1% and flexor tendon rupture was avoided by early metalware removal. This study demonstrates tendon injuries are not uncommon after distal radius fractures, and close examination and follow-up are necessary to prevent eventual rupture. Plate prominence at the time of fixation should be minimised to reduce the risk of rupture

Tendon injuries present a major clinical challenge, as they necessitate surgical intervention and are prone to fibrotic progression. Despite advances in physical therapy and surgical technique, tendons fail to return to full native functioning, underlining the need for a biological therapeutic to improve tendon healing. Myofibroblasts are activated fibroblasts that participate in the proliferative and remodeling phases of wound healing, and while these matrix-producing cells are essential for proper healing, they are also linked to fibrotic initiation. A subset of tenocytes has been shown to give rise to the myofibroblast fate, and potentially contribute to fibrotic tendon healing. A viable anti-fibrotic therapy in other tissues has been reprogramming the fibroblast-myofibroblast differentiation route, avoiding a more pro-fibrotic myofibroblast phenotype. Thus, defining the molecular programs that underlie both physiological and pathological tendon healing is critical for the development of potential pharmacologic treatments. Towards that end, we have taken advantage of spatial transcriptomics, using the tenocyte marker Scleraxis as a tool, and have outlined three major spatiotemporally distinct tenocyte differentiation trajectories (synthetic, proliferative, and reactive) following acute tendon injury in mouse FDL. We have further outlined key transcriptional controls that may be manipulated to alter the differentiation process and influence the resulting myofibroblast phenotype, thereby promoting regenerative tendon healing

The October 2023 Wrist & Hand Roundup. 360. looks at: Distal radius fracture management: surgeon factors markedly influence decision-making; Fracture-dislocation of the radiocarpal joint: bony and capsuloligamentar management, outcomes, and long-term complications; Exploring the role of artificial intelligence chatbot in the management of scaphoid fractures; Role of ultrasonography for evaluation of nerve recovery in repaired median nerve lacerations; Four weeks versus six weeks of immobilization in a cast following closed reduction for displaced distal radial fractures in adult patients: a multicentre randomized controlled trial; Rehabilitation following flexor tendon injury in Zone 2: a randomized controlled study; On the road again: return to driving following minor hand surgery; Open versus single- or dual-portal endoscopic carpal tunnel release: a meta-analysis of randomized controlled trials

Traumatic acute or chronic tendon injuries are a wide clinical problem in modern society, resulting in important economic burden to the health system and poor quality of life in patients. Due to the low cellularity and vascularity of tendon tissue the repair process is slow and inefficient, resulting in mechanically, structurally, and functionally inferior tissue. Tissue engineering and regenerative medicine are promising alternatives to the natural healing process for tendon repair, especially in the reconstruction of large damaged tissues. The aim of TRITONE project is to develop a smart, bioactive implantable 3D printed scaffold, able to reproduce the structural and functional properties of human tendon, using FDA approved materials and starting from MSC and their precursor, MPC cell mixtures from human donors. Total cohort selected in the last 12 months was divided in group 1 (N=20) of subjects with tendon injury and group 2 (N=20) of healthy subject. Groups were profiled and age and gender matched. Inclusion criteria were age>18 years and presence of informed consent. Ongoing pregnancy, antihypertensive treatment, cardiovascular diseases, ongoing treatment with anti-aggregants, acetylsalicylic-acid or lithium and age<18 years were exclusion criteria. Firstly, we defined clinical, biological, nutritional life style and genetic profile of the cohort. The deficiency of certain nutrients and sex hormonal differences were correlated with tendon-injured patients. It was established the optimal amount of MPC/MSC human cell (collected from different patients during femoral neck osteotomy). Finally, most suitable biomaterials for tendon regeneration and polymer tendon-like structure were identified. Hyaluronic acid, chemical surface and soft-molecular imprinting (SOFT-MI) was used to functionalize the scaffold. These preliminary results are promising. It will be necessary to enroll many more patients to identify genetic status connected with the onset of tendinopathy. The functional and structural characterization of smart bioactive tendon in dynamic environment will represent the next project step

Aims. Posterior malleolar (PM) fractures are commonly associated with ankle fractures, pilon fractures, and to a lesser extent tibial shaft fractures. The tibialis posterior (TP) tendon entrapment is a rare complication associated with PM fractures. If undiagnosed, TP entrapment is associated with complications, ranging from reduced range of ankle movement to instability and pes planus deformities, which require further surgeries including radical treatments such as arthrodesis. Methods. The inclusion criteria applied in PubMed, Scopus, and Medline database searches were: all adult studies published between 2012 and 2022; and studies written in English. Outcome of TP entrapment in patients with ankle injuries was assessed by two reviewers independently. Results. Four retrospective studies and eight case reports were accepted in this systematic review. Collectively there were 489 Pilon fractures, 77 of which presented with TP entrapment (15.75%). There were 28 trimalleolar fractures, 12 of which presented with TP entrapment (42.86%). All the case report studies reported inability to reduce the fractures at initial presentation. The diagnosis of TP entrapment was made in the early period in two (25%) cases, and delayed diagnosis in six (75%) cases reported. Using modified Clavien-Dindo complication classification, 60 (67%) of the injuries reported grade IIIa complications and 29 (33%) grade IIIb complications. Conclusion. TP tendon was the commonest tendon injury associated with pilon fracture and, to a lesser extent, trimalleolar ankle fracture. Early identification using a clinical suspicion and CT imaging could lead to early management of TP entrapment in these injuries, which could lead to better patient outcomes and reduced morbidity. Cite this article: Bone Jt Open 2024;5(3):252–259

Intimate partner violence (IPV) causes significant morbidity and its unlikely to be reported compared to other forms of gender-based violence (GBV). For early detection, understanding Orthopaedic injuries from GBV is vital. This study assesses the pattern of musculoskeletal injuries from GBV and determines the factors associated with it. It is a retrospective observational study of patients aged ≥18 years, with GBV-related acute Orthopaedic injuries. Data was reviewed from January 2021 to December 2021, including, demographic information, soft tissue and bony injuries, relationship to assailant, substance abuse and the day and time of injury. Frequencies and percentages for categorical data were analysed. Chi-square test was used to calculate association. T-test was used to compare groups for continuous & categorical variables. Multivariate analysis was conducted to find the odds ratio and a p-value <0.05 was statistically significant. 138 patients were included, the mean age at presentation being 35.02 years (SD=11). 92.75% of GBV victims were females. Most were unemployed (66.7%). 30.43% (n-42) had a soft tissue injury; superficial laceration being the most common (23.1%), flexor tendon injury (10.87%), hand abscess (5.8%), and extensor tendon injury (5.07%). 71.02 % (n=98) sustained appendicular fractures. 51.45% (n=71) sustained upper limb fractures; distal radius fractures (10.86%) and distal 3rd ulnar fractures (9,42%). 19.57% (n=27) had lower limb fractures; 7.25% (n=10) had lateral malleolus ankle fractures. 63.7% (n=80) of cases were by an intimate partner on weekends (50.73%). 62.31% occurred between 16h00 and 0h00. 41.1% (n=65) reported alcohol abuse. 63.04% had surgery. GBV likely occurs in early middle-aged females by intimate partners influenced by alcohol over the weekends between 16h00 to 0h00. Distal radius/distal 3rd ulnar fractures are the most common bony injuries. Superficial wrist laceration is the commonest soft tissue injury. These findings may assist with early detection and intervention to prevent adverse outcomes in GBV

Introduction and Objective. Zone 2 flexor tendon injuries are still one of the challenges for hand surgeons. It is not always possible to achieve perfect results in hand functions after these injuries. There is no consensus in the literature regarding the treatment of zone 2 flexor tendon injuries, tendon repair and surgical technique to be applied to the A2 pulley. The narrow fibro-osseous canal structure in zone 2 can cause adhesions and loss of motion due to the increase in tendon volume due to surgical repair. Different surgical techniques have been defined to prevent this situation. In our study, in the treatment of zone 2 flexor tendon injuries; Among the surgical techniques to be performed in addition to FDP tendon repair; We aimed to compare the biomechanical results of single FDS slip repair, A2 pulley release and two different pulley plasty methods (Kapandji and V-Y pulley plasty). Materials and Methods. In our study, 12 human upper extremity cadavers preserved with modified Larssen solution (MLS) and amputated at the mid ½ level of the arm were used. A total of 36 fingers (second, third and the fourth fingers were used for each cadaver) were divided into four groups and 9 fingers were used for each group. With the finger fully flexed, the FDS and FDP tendons were cut right in the middle of the A2 pulley and repaired with the cruciate four-strand technique. The surgical techniques described above were applied to the groups. Photographs of fingers with different loads (50 – 700 gr) were taken before and after the application. Proximal interphalangeal (PIP) joint angle, PIP joint maximum flexion angle and bowstring distance were measured. The gliding coefficient was calculated by applying the PIP joint angle to the single-phase exponential association equation. Results. Gliding coefficient after repair increased by %21.46 ± 44.41, %62.71 ± 116.9, %26.8 ± 35.35 and %20.39 ± 28.78 in single FDS slip repair, A2 pulley release, V-Y pulley plasty and Kapandji plasty respectively. The gliding coefficient increased significantly in all groups after surgical applications (p<0.05). PIP joint maximum flexion angle decreased by %3.17 ± 7.92, %12.82 ± 10.94, %8.33 ± 3.29 and %7.35 ± 5.02 in single FDS slip repair, A2 pulley release, V-Y pulley plasty and Kapandji plasty respectively. PIP joint maximum flexion angle decreased significantly after surgery in all groups (p<0.05). However, there was no statistically significant difference between surgical techniques for gliding coefficient and PIP joint maximum flexion angle. Bowstring distance between single FDS slip repair, kapandji pulley plasty and V-Y pulley plasty showed no significant difference in most loads (p>0.05). Bowstring distance was significantly increased in the A2 pulley release group compared to the other three groups (p<0.05). Conclusion. Digital motion was negatively affected after flexor tendon repair. Similar results were found in terms of gliding coefficient and maximum flexion angle among different surgical methods. As single FDS slipe repair preserves the anatomical structure of the A2 pulley therefore we prefer it as an ideal method for zone 2 flexor tendon repair. However, resection of FDS slip may jeopardizes nutrition to the flexor digitorum profundus tendon which weakens the repair site. Therefore the results must be confirmed by an in vivo study before a clinical recommendation can be made. Keywords: Flexor tendon; injury; pulley plasty; cadaver;

Olecranon plates used for the internal fixation of complex olecranon fractures are applied directly over the triceps tendon on the posterior aspect of the olecranon. The aim of the study is to describe the relationship of the plates and screws to the triceps tendon at the level of the olecranon. Eight cadaveric elbows were used. Dimensions of the triceps tendon at the insertion and 1cm proximal were measured. A long or a short olecranon plate was then applied over the olecranon and the most proximal screw applied. The length of the plate impinging on the tendon and the level of the screw tract on the tendon and bone were measured. The mean olecranon height was 24.3cm (22.4-26.9cm) with a tip-to-tendon distance of 14.5cm (11.9-16.2cm). The triceps tendon footprint averaged 13.3cm (11.7-14.9cm) and 8.8cm (7.6-10.2cm) in width and length, respectively. The mean width of the central tendon 1 cm proximal to the footprint was 6.8 cm. The long olecranon plate overlay over more movable tendon length than did the short plate and consequently the superior screw pierced the triceps tendon more proximally with the long plate. Using the Mann-Whitney U test, the differences were significant. The long olecranon plates encroach on more triceps tendon than short plates. This may be an important consideration for olecranon fractures with regards implant loosening or triceps tendon injury

Approximately 30% of general practice consultations for musculoskeletal pain are related to tendon disorders, causing substantial personal suffering and enormous related healthcare costs. Treatments are often prone to long rehabilitation times, incomplete functional recovery, and secondary complications following surgical repair. Overall, due to their hypocellular and hypovascular nature, the regenerative capacity of tendons is very poor and intrinsically a disorganized scar tissue with inferior biomechanical properties forms after injury. Therefore, advanced therapeutic modalities need to be developed to enable functional tissue regeneration within a degenerative environment, moving beyond pure mechanical repair and overcoming the natural biological limits of tendon healing. Our recent studies have focused on developing biologically augmented treatment strategies for tendon injuries, aiming at restoring a physiological microenvironment and boosting endogenous tissue repair. Along these lines, we have demonstrated that the local application of mesenchymal stromal cell-derived small extracellular vesicles (sEVs) has the potential to improve rotator cuff tendon repair by modulating local inflammation and reduce fibrotic scarring. In another approach, we investigated if the local delivery of the tendon ECM protein SPARC, which we previously demonstrated to be essential for tendon maturation and tissue homeostasis, has the potential to enhance tendon healing. Finally, I will present results demonstrating the utility of nanoparticle-delivered, chemically modified mRNAs (cmRNA) to improve tendon repair

Poor tendon repair is an unsolved issue in clinical practice, due to complex tendon structure. Tendon stem/progenitor cells (TSPCs) play key roles in homeostasis, regeneration, and inflammation regulation in acute tendon injuries, and rely on TGF-β signaling for recruitment into degenerative tendons. In this study, we aimed to develop an in vitro model for tenogenesis adopting a dynamic culture of a fibrin 3D scaffold, bioengineered with human TSPCs collected from both healthy and tendinopathic surgery explants (Review Board prot./SCCE n.151, 29 October 2020). 3D culture was maintained for 21 days under perfusion provided by a custom-made bioreactor, in a medium supplemented with hTGF-β1 at 20 ng/mL. The data collected suggested that the 3D in vitro model well supported survival of both pathological and healthy cells, and that hTGF-β signaling, coupled to a dynamic environment, promoted differentiation events. However, pathological hTSPCs showed a different expression pattern of tendon-related genes throughout the culture and an impaired balance of pro-inflammatory and anti-inflammatory cytokines, compared to healthy hTSPCs, as indicated by qRT-PCT and immunofluorescence analyses. Additionally, the expression of both tenogenic and cytokine genes in hTSPCs was influenced by hTGF-β1, indicating that the environment assembled was suitable for studying tendon stem cells differentiation. The study offers insights into the use of 3D cultures of hTSPCs as an in vitro model for investigating their behavior during tenogenic events and opens perspectives for following the potential impact on resident stem cells during regeneration and healing events

Our study sought to establish the necessity of prolonged pre-operative antibiotic prophylaxis in patients presenting with zone II and zone V acute flexor tendon injuries (FTI). We hypothesized that a single dose of prophylactic antibiotic was adequate in prevention of post-operative wound infection in acute zone II and V FTI. This was a prospective study of 116 patients who presented with zone II and zone V acute FTI. The study included patients who were 18 years and older. Those with macroscopic contamination, immunocompromised, open fractures, bite injuries, and crush injuries were excluded. Patients were randomised into a group receiving a single dose of prophylactic antibiotic and another group receiving a continuous 8 hourly antibiotic doses until the day of surgery. Each group was subdivided into occupational and non-occupational injuries. Their post-operative wound outcomes were documented 10 – 14 days after surgery. The wound outcome was reported as no infection, superficial infection (treated with wound dressings), and deep infection (requiring surgical debridement). There was 0.9% rate of deep post-operative wound infections, which was a single zone V acute FTI case in a single dose prophylactic antibiotic group. There was a 7.8% superficial post-operative wound infection rate, which was mainly zone II acute FTI in both antibiotic groups. There was a strong association between zone II acute FTI and post-operative wound infection (p < 0.05). There was no association between (antibiotic dosage or place of injury) with post-operative wound infection (p > 0.05). There is no benefit in prescribing prolonged pre-operative antibiotic in patients with acute, simple lacerations to zone II and zone V FTI if there is no macroscopic wound contamination

Tendon injury is debilitating and recalcitrant. With limited knowledge of disease aitiology we have are lacking in effective treatments for this prevalent musculoskeletal complaint. This presentation will outline our findings over the past few years in which we have demonstrated the importance of the interfascicular matrix (IFM) niche in maintaining healthy tendon function and driving disease progression. 1,2. It will also continue to describe our progress in developing both in vivo and in vitro models to interrogate disease progression. We have developed and validated a rat Achilles tendon overload model, in order to explore the impact of loading on IFM and fascicle structure, and the resulting cell response. Data highlights that structural disruption and inflammatory response both initiate in the IFM region, and can be seen in the absence of demonstrable changes to animal gait, indicating a sub-injury response in the tendon which we hypothesis may drive increased matrix turnover and repair. 3. . We are now looking to interrogate the pathways driving this inflammatory behaviour in an organ-chip model, exploring the interplay between IFM cells and cells within fascicles. We have demonstrated phenotypic distinction of cells from the two niche environments, localized the progenitor phenotype to the IFM region and demonstrated significant mechanosensitivity in the IFM cell population. 4. We are currently building appropriate niche environments to maintain cell phenotype in our in vitro models, to explore the metabolic changes associated with disease progression. Acknowledgements: This body of work has received funding from: BBSRC (BB/K008412 /1); Versus Arthritis (project grant 20262); Horserace Betting Levy Board (T5); Dunhill Medical Charity (project grant RPGF1802\23); MRC (MR/T015462/1)

Tendons mainly consist of collagen in order to withstand high tensile forces. Compared to other, high turnover tissues, cellularity and vascularity in tendons are low. Thus, the natural healing process of tendons takes long and can be problematic. In case of injury to the enthesis, the special transition from tendon over cartilage to bone is replaced by a fibrous scar tissue, which remains an unsolved problem in rotator cuff repair. To improve tendon healing, many different approaches have been described using scaffolds, stem cells, cytokines, blood products, gene therapy and others. Despite promising in vitro and in vivo results, translation to patient care is challenging. In clinics however, tendon auto- or allografts remain still first choice to augment tendon healing if needed. Therefore, it is important to understand natural tendon properties and natural tendon healing first. Like in other tissues, senescence of tenocytes seems to play an important role for tendon degeneration which is interestingly not age depended. Our in vivo healing studies have shown improved and accelerated healing by adding collagen type I, which is now used in clinics, for example for augmentation of rotator cuff repair. Certain cytokines, cells and scaffolds may further improve tendon healing but are not yet used routinely, mainly due to missing clinical data, regulatory issues and costs. In conclusion, the correct diagnosis and correct first line treatment of tendon injuries are important to avoid the necessity to biologically augment tendon healing. However, strategies to improve and accelerate tendon healing are still desirable. New treatment opportunities may arise with further advances in tendon engineering in the future

Tendon injuries occur frequently in athletes and the general population, with inferior healing leading to deposition of fibrotic scar tissue. New treatments are essential to limit fibrosis and enable tendon regeneration post-injury. In this study, we tested the hypothesis that rapamycin improves tendon repair and limits fibrosis by inhibiting the mTOR pathway. The left hindlimb of female adult Wistar rats was injured by needle puncture and animals were either given daily injections of rapamycin (2mg/kg) or vehicle. Animals were euthanized 1 week or 3 weeks post-injury (n=6/group). Left and right Achilles tendons were harvested, with the right limbs acting as controls. Tendon sections were stained with haematoxylin & eosin, and scored by 2 blinded scorers, assessing alterations in cellularity, cell morphology, vascularity, extracellular matrix (ECM) organization and peritendinous fibrosis. Immunohistochemistry was performed for the tendon pan-vascular marker CD146 and the autophagy marker LC3. Injury resulted in significantly altered ECM organization, cell morphology and cellularity in both rapamycin and vehicle-treated groups, but no alterations in vascularity compared to uninjured tendons. Rapamycin had a limited effect on tendon repair, with a significant reduction in peritendinous fibrosis 3 weeks after injury (p=0.028) but no change in cell morphology, cellularity or ECM organization compared to vehicle treated tendons at either 1 week or 3 weeks post injury. CD146 labelling was increased at the site of injury, but there was no apparent difference in CD146 or LC3 labelling in rapamycin and vehicle treated tendons. The decrease in peritendinous fibrosis post-injury observed in rapamycin treated tendons indicates rapamycin as a potential therapy for tendon adhesions. However, the lack of improvement of other morphological parameters in response to rapamycin treatment indicates that rapamycin is not an effective therapy for injuries to the tendon core. Acknowledgements: This study was funded by Versus Arthritis (22607)

Cell-based therapies offer a promising strategy to treat tendon injuries and diseases. Both mesenchymal stromal cells (MSCs) and pluripotent stem cells (PSCs) are good candidates for such applications due to their self-renewing and differentiation capacity. However, the translation of cell-based therapies from bench to bedside can be hindered by the use of animal-derived components in ancillary materials and by the lack of standardised media and protocols for in vitro tenogenic differentiation. To address this, we have optimized animal component-free (ACF) workflows for differentiating human MSCs and PSCs to tenocyte-like cells (TLCs) respectively. MSCs isolated from bone marrow (n = 3) or adipose tissue (n = 3) were expanded using MesenCult™-ACF Plus Culture Kit for at least 2 passages, and differentiated to TLCs in 21 days using a step-wise approach. Briefly, confluent cultures were treated with an ACF tenogenic induction medium for 3 days, followed by treatment with an ACF maturation medium for 18 days. Monolayer cultures were maintained at high density without passaging for the entire duration of the protocol, and the medium was changed every 2 – 3 days. In a similar fashion, embryonic (n = 3) or induced PSCs (n = 3) were first differentiated to acquire a mesenchymal progenitor cell (MPC) phenotype in 21 days using STEMdiff™ Mesenchymal Progenitor Kit, followed by the aforementioned tenogenic protocol for an additional 21 days. In all cases, the optimized workflows using ACF formulations consistently activated a tenogenic transcriptional program, leading to the generation of elongated, spindle-shaped tenomodulin-positive (TNMD+) cells and deposition of an extracellular matrix predominantly composed of collagen type I. In summary, here we describe novel workflows that can robustly generate TLCs from MSCs and hPSC-derived MPCs for potential translational applications

Background. Disability and slow return to sport and work after tendon rupture are major challenges. Platelet Rich Plasma (PRP) is an autologous supraphysiological concentration of platelets from whole blood that has demonstrated positive cellular and physiological effects on healing in laboratory conditions but evidence from adequately powered robust clinical trials is lacking. We aimed to determine the clinical efficacy of PRP for treatment of acute Achilles tendon rupture. Methods. In a placebo-controlled, participant- and assessor-blinded, trial at 19 NHS hospitals we randomly assigned 230 adults starting acute Achilles rupture non-surgical management to PRP injection or dry-needle insertion (placebo) to the rupture gap under local anaesthetic. Patients with confounding or contraindicated concurrent medical conditions were excluded. The primary outcome was muscle-tendon function, assessed by the limb symmetry index (LSI, uninjured limb/injured limb × 100, higher scores better) of the work (Joules) performed during the heel-rise endurance test at 24 weeks. Secondary outcomes were: Achilles Tendon Rupture Score (ATRS, 0–100, higher scores better), quality of life (SF-12), pain, and goal attainment. Trial registration: ISRCTN54992179. Results. Participants were aged mean 46 years and 57 (25%) were female. 103/114 (90%) of the PRP group and all (n=116) in the placebo group received allocated treatment. At 24 weeks, mean LSI was 34.4 for the PRP group and 38.8 for placebo (adjusted mean difference −4.4 95% CI −11.2 to 2.5, n=201) and ATRS was mean 65.2 PRP vs 65.8 (adjusted mean difference −0.6, 95% CI −4.9 to 3.7, n=224). There were no differences between groups in the other secondary outcomes. Conclusion. We found no evidence of PRP efficacy for improving muscle-tendon function or patient-reported recovery after acute Achilles tendon rupture. Our findings challenge the increasing global use of PRP for acute tendon injury and indicate that robust evaluations are required in other applications

Worldwide, tendon disorders are one of the main causes of disability that decrease the quality of life of individuals and represent a substantial economic burden on society. Currently, the main therapies used for tendon injuries are not able to restore tendon functionality, and due to tendons' hypovascular and hypocellular nature, they present a reduced healing capacity, which also limits the success of the available therapies. In order to discover new therapies, extracellular vesicles (EVs), key players in cell-cell communication, have been widely explored for tissue engineering and regenerative medicine applications. Thus, the aim of this study is to assess the role of EVs derived from platelets in stem cell tenogenic commitment using a bioengineered tendon in vitro model for potential use as tendon therapeutic agents. Biomimetic platelet-derived EVs were produced by freeze-thaw cycles of platelets and isolation at different centrifugation speed. To recreate the architecture of tendons, a 3D system consisting of electrospun anisotropic nanofiber scaffolds coated with collagen encapsulating human adipose stem cells (hASCs) and different types of platelet-derived EVs, were produced. Then, the influence of the tendon-mimetic constructs and the distinct EVs populations in the hASCs tenogenic differentiation were assessed over culture time. We observed that the hASCs on the nanofibrous tendon scaffolds, show high cytoskeleton anisotropic organization that is characteristic of tenocytes. Moreover, acting as biological cues, platelet-derived EVs boosted hASCs tenogenic commitment, supported by the increased gene expression of tendon-related markers (SCX and TNMD). Additionally, EVs enhanced the deposition of tendon like extracellular matrix (ECM), as evidenced by the increased gene expression of ECM-related markers such as COL1, COL3, DCN, TNC, and MMP-3, which are fundamental for ECM synthesis and degradation balance. Moreover, EVs induced lower collagen matrix contraction on hASCs, which has been related with lower myofibroblast differentiation. Overall, the results revealed that EVs are capable of modulating stem cells' behavior boosting their tenogenic commitment, through the increased expression of healthy tendon cell markers, potentiating ECM deposition and decreasing cell contractility. Therefore, platelet EVs are a promising biochemical tool, worthy to be further explored, as paracrine signaling that might potentiate tendon repair and regeneration

Common tendon injuries impair healing, leading to debilitation and an increased re-rupture risk. The impact of oxygen-sensing pathways on repair mechanisms, vital in regulating inflammation and fibrosis, remains unclear despite their relevance in tendon pathologies. Recent studies show that pulsed electromagnetic field (PEMF) reduce inflammation in human tendon cells (hTDCs) and in hypoxia-induced inflammation. We investigated the hypoxia's impact (1% and 2% oxygen tension) using magnetic cell sheet constructs (IL-1β-magCSs) primed with IL-1β. IL-1β-magCSs were exposed to low OT (1h, 4h,6h) in a hypoxic chamber. To confirm the role of PEMF (5Hz, 4mT, 50% duty cycle) on hypoxia modulation, IL-1β-magCSs, previously exposed to OT, were 1h-stimulated with PEMF. Our results show a significant increase in HIF- 1a and HIF-2a expression on IL-1β-magCSs after exposure to 2%-OT at all time points, compared to 1%- OT and normoxia. TNFa, IL-6, and IL-8 expression increased after 6 hours of 1%-OT exposure. PEMF stimulation of hypoxic IL-1β-magCSs led to decreased pro-inflammatory genes and increased anti-inflammatory (IL-4,IL-10) expression compared to unstimulated magCSs. IFN-g, TNF-α, and IL-6 release increased after 6 hours, regardless of %-OT, while IL-10 levels tended to rise after PEMF stimulation at 2%-OT. Also, NFkB expression was increased on IL-1β-magCSs exposed to 4 h and 6 h of 2%-OT, suggesting a link between NFkB and the production of pro-inflammatory factors. Moreover, PEMF stimulation showed a significantly decreased NFkB level in IL-1β-magCSs. Overall, low OT enhances expression of hypoxia-associated genes and inflammatory markers in IL-1β-magCSs with the involvement of NFkB. PEMF modulates the response of magCSs, previously conditioned to hypoxia and to inflammatory triggers, favouring expression of anti-inflammatory genes and proteins, supporting PEMF impact in pro-regenerative tendon strategies. Acknowledgements: ERC CoG MagTendon(No.772817), FCT under the Scientific Employment Stimulus-2020.01157.CEECIND. Thanks to Hospital da Prelada for providing tendon tissue samples (Portugal), and TERM. RES Hub (Norte-01-0145-FEDER-022190)

Tendinopathy is a tendon pathology often resulting from a failed healing response to tendon injury. Activated protein C (APC) is a natural anti-coagulant with anti-inflammatory and wound healing promoting functions, which are mainly mediated by its receptors, endothelial protein C receptor (EPCR) and protease activated receptors (PARs). This study aimed to determine whether APC stimulates tenocyte healing and if so, to assess the involvement of the receptors. Mouse-tail tenocytes were isolated from 3-week-old wild type (WT), PAR- 1 knockout (KO) and PAR-2 KO mice. The expression of EPCR, PAR-1 and −2 and the effect of APC on tenocytes tendon healing and the underlying mechanisms were investigated by Reverse transcription real time PCR, western blot, 3- (4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) assay, zymography, and scratch wound healing/ migration assay. When compared to WT cells, PAR-1 KO tenocytes showed increased cell proliferation (3.3-fold, p<0.0001), migration (2.7-fold, p<0.0001) and wound healing (3-fold, p<0.0001), whereas PAR-2 KO cells displayed decreased cell proliferation (0.6-fold, p<0.05) and no change in cell migration or wound healing. APC at 1 μg/ml stimulated WT and PAR-1 KO tenocyte proliferation (~1.3, respectively, p<0.05) and wound healing (~1.3-fold, respectively, p<0.05), and additionally promoted PAR1-KO cell migration (1.4-fold, p<0.0001). APC only increased the migration (2-fold, p<0.05) of PAR-2 KO tenocytes. The activation of AKT, extracellular signal-regulated kinase (ERK)-2, and glycogen synthase kinase (GSK)-β3, the intracellular molecules that are associated with cell survival/growth, and matrix metalloproteinase (MMP)-2 that is related to cell migration and wound healing, were increased in all three cell lines in response to APC treatment. These findings show that PAR-1 and PAR-2 act differentially in tenocyte proliferation/migration/wound healing. APC likely promotes tenocyte proliferation/ wound healing via PAR-2, not PAR-1

Chronic Achilles tendinopathy is characterised by sub-acute inflammation with pro-inflammatory type 1 macrophages (M1), tissue degeneration and consequent partial or total tendon injury. Control of the inflammatory response and M1-to-M2 macrophage polarisation can favour tendon healing both directly and indirectly, by allowing for the regenerative process driven by local mesenchymal stem cells. Ten patients (3 females and 7 males aged between 32 and 71 years old) with partial Achilles tendon injury were treated with injections of autologous peripheral blood mononuclear cells (PB-MNCs). The cell concentrate was obtained from 100-120 cc of each patient's blood with a selective point-of-care filtration system. PB-MNCs remained trapped in the filter and were injected immediately after sampling. Around 60% of the PB-MNC concentrate was injected directly into the injured area, while the remaining 40% was injected in smaller amounts into the surrounding parts of the Achilles tendon affected by tendinosis. All patients were evaluated both clinically with the help of the American Orthopaedic Foot & Ankle Society (AOFAS) scale, and radiologically (MRI examination) at baseline and 2 months after the PB-MNC injection. A clinical reassessment with the AOFAS scale was also performed 6 months after the intervention. The rehabilitation protocol implied full weight-bearing walking immediately after the procedure, light physical activity 3-4 days after the injection, and physiotherapist-assisted stretching exercises and eccentric training. In all patients, functional and radiological signs of tendon healing processes were detected as early as 2 months after a single treatment and the AOFAS scale rose from the initial mean value of 37.5 (baseline) to 85.4 (6 months). Our preliminary results indicate that regenerative therapies with PB-MNCs can prove useful for partial Achilles tendon injuries as a valid alternative to surgical options, especially when other conservative approaches have failed. Advantages of this therapy include rapid execution, no need for an operating theatre, easy reproducibility, quick recovery and good tolerability regardless of the patient's age (the procedure is not to be performed in subjects who are below 18 years old). Further studies on the topic are recommended to confirm these observations

Tendon injuries are a common problem that can significantly impact an individual's quality of life. While traditional surgical methods have been used to address this issue, Extracellular Vesicles (EVs) have emerged as a promising approach to promote tendon repair and regeneration mechanisms, as they deliver specific biological signals to neighbouring cells. In this study, we extracted human Tendon Progenitor Stem cells (hTPSCs) from surgery explants and isolated their EVs from perfused and static media. hTPSCs were isolated from tendon surgery biopsy (Review Board prot./SCCE n.151, 29/10/2020) and cultured in both static and dynamic conditions, using a perfusion bioreactor (1ml/min). When cells reached 80% confluence, they were switched into a serum-free medium for 24 hours for EVs-production. Conditioned media was ultra-centrifuged for 90min (100000g). The recovered pellet was then characterized by size and concentration (Nanosight NS300), Zeta potential (Mastersizer S), morphology (SEM and TEM) and protein quantification. hTPSCs stemness and multipotency were confirmed through CD73, CD90, and CD105 expression and confirmation of quad-lineage (adipo-osteo-chondro-teno) differentiation. After 7 days, hTPSCs were ready for EVs-production. Ultracentrifugation revealed the presence of particles with a concentration of 7×107 particles/mL consistent across both cultures. Further characterization indicated that EVs collected from perfused conditions displayed an elevated vesicle mean size (mean 143±6.5 nm) in comparison to static conditions (mean 112±7.4 nm). Consistent with, but not in proportion with, the above protein content was measured at 20 ng/ml (dynamic) and 7 ng/mL (static) indicating a nearly 3-fold increase in concentration associated with a ~22% increase in particle size. Proposed data showed that sub-200 diameter vesicles were successfully collected from multipotent hTPSCs starvation, and the vesicle size and protein concentration were compatible with established EV literature; furthermore, dynamic culture conditions seemed more suitable for EVs-production. Further characterization will be required to better understand, EVs-compositions and their role in tendon regenerative events

Traditionally, sports Injuries have been sub-optimally managed through Emergency Departments (ED) in the public health system due to a lack of adequate referral processes. Fractures are ruled out through plain radiographs followed by a reactive process involving patient initiated further follow up and investigation. Consequently, significant soft tissue and chondral injuries can go undiagnosed during periods in which early intervention can significantly affect natural progression. The purpose of this quality improvement project was to assess the efficacy of an innovative Sports Injury Pathway introduced to detect and treat significant soft tissue injuries. A Sports Injury Pathway was introduced at Fiona Stanley Hospital (WA, Australia) in April 2019 as a collaboration between the ED, Physiotherapy and Orthopaedic Departments. ED practitioners were advised to have a low threshold for referral, especially in the presence of a history of a twisting knee injury, shoulder dislocation or any suggestion of a hip tendon injury. All referrals were triaged by the Perth Sports Surgery Fellow with early follow-up in our Sports Trauma Clinics with additional investigations if required. A detailed database of all referrals was maintained, and relevant data was extracted for analysis over the first 3 years of this pathway. 570 patients were included in the final analysis. 54% of injuries occurred while playing sport, with AFL injuries constituting the most common contact-sports injury (13%). Advanced Scope Physiotherapists were the largest source of referrals (60%). A total of 460 MRI scans were eventually ordered comprising 81% of total referrals. Regarding Knee MRIs, 86% identified a significant structural injury with ACL injuries being the most common (33%) followed by isolated meniscal tears (16%) and multi-ligament knee injuries (11%). 95% of Shoulder MRI scans showed significant pathology. 39% of patients required surgical management, and of these 50% were performed within 3 months from injury. The Fiona Stanley Hospital Sports Injury Pathway has demonstrated its clear value in successfully diagnosing and treating an important cohort of patients who present to our Emergency Department. This low threshold/streamlined referral pathway has found that the vast majority of these patients suffer significant structural injuries that may have been otherwise missed, while providing referring practitioners and patients access to prompt imaging and high-quality Orthopaedic sports trauma services. We recommend the implementation of a similar Sports Injury Pathway at all secondary and tertiary Orthopaedic Centres

The 2020 London International Hamstring Consensus meeting was convened to improve our understanding and treatment of hamstring injuries. The multidisciplinary consensus panel included 14 International specialists on the management of hamstring injuries. The Delphi consensus process consisted of two rounds of surveys which were completed by 19 surgeons from a total of 106 participants. Consensus on individual statements was regarded as over 70% agreement between panel members. The consensus group agreed that the indications for operative intervention included the following: gapping at the zone of injury (86.9%); high functional demands of the patient (86.7%); symptomatic displaced bony avulsions (74.7%); and proximal free tendon injuries with functional compromise refractory to non-operative treatment (71.4%). Panel members agreed that surgical intervention had the capacity to restore anatomy and function, while reducing the risk of injury recurrence (86.7%). The consensus group did not support the use of corticosteroids or endoscopic surgery without further evidence. These guidelines will help to further standardise the treatment of hamstring injuries and facilitate decision-making in the surgical treatment of these injuries

Objectives. Emerging evidence indicates that tendon disease is an active process with inflammation that is critical to disease onset and progression. However, the key cytokines responsible for driving and sustaining inflammation have not been identified. Methods. We performed a systematic review of the literature using MEDLINE (U.S. National Library of Medicine, Bethesda, Maryland) in March 2017. Studies reporting the expression of interleukins (ILs), tumour necrosis factor alpha (TNF-α) and interferon gamma in diseased human tendon tissues, and animal models of tendon injury or exercise in comparison with healthy control tissues were included. Results. IL-1β, IL-6, IL-10, and TNF-α are the cytokines that have been most frequently investigated. In clinical samples of tendinopathy and tendon tears, the expression of TNF-α tended not to change but IL-6 increased in tears. Healthy human tendons showed increased IL-6 expression after exercise; however, IL-10 remained unchanged. Animal tendon injury models showed that IL-1β, IL-6, and TNF-α tend to increase from the early phase of tendon healing. In animal exercise studies, IL-1β expression showed a tendency to increase at the early stage after exercise, but IL-10 expression remained unchanged with exercise. Conclusions. This review highlights the roles of IL-1β, IL-6, IL-10, and TNF-α in the development of tendon disease, during tendon healing, and in response to exercise. However, there is evidence accumulating that suggests that other cytokines are also contributing to tendon inflammatory processes. Further work with hypothesis-free methods is warranted in order to identify the key cytokines, with subsequent mechanistic and interaction studies to elucidate their roles in tendon disease development. Cite this article: W. Morita, S. G. Dakin, S. J. B. Snelling, A. J. Carr. Cytokines in tendon disease: A Systematic Review. Bone Joint Res 2017;6:656–664. DOI: 10.1302/2046-3758.612.BJR-2017-0112.R1

Tendon injuries in both the human and horse represent a challenge due to persistent inflammation combined with inadequate reparative cells and a poorly organised extracellular matrix. The potential of mesenchymal stem cells (MSCs) in regenerating tendon injuries remains to be fully realised. The main mechanism of action by MSCs is considered to be primarily mediated via paracrine mechanisms. This may involve the production and release of extracellular vesicles (EVs) by stem cells with a sub-fraction of these EVs (<100 nm diameter) called exosomes that appear to be the main paracrine effectors. EVs can be readily prepared from MSCs and offer a clinically relevant therapy. However, EVs for tendon repair need to be fully characterised. The horse represents a highly relevant model of tendon and ligament injuries as it shares many features of mechanical loading, function and aetiopathology with the human. We have isolated and characterised EVs from equine MSCs for modulating tendon cell phenotype in an in vitro tendon injury model using IL-1ß. EVs can be isolated from IL-1ß stimulated MSCs although their levels are not significantly increased over controls suggesting that the nature of the stimulated EV cargo may be more important than absolute levels of released EVs

At first-stage revision surgery for infection of total knee arthroplasties, antibiotic-impregnated cement spacers are frequently implanted. Two types of cement spacers are commonly used, “static” and “articulating” cement spacers. Advocates of cement spacers state that they deliver high doses of antibiotics locally, increase patient comfort, allow mobility and provide joint stability. They also minimize contracture of collateral ligaments, thereby facilitating re-implantation of a definitive prosthesis at a later stage. The use of these cement spacers, however, are not without significant complications, including patella tendon injuries. We describe a series of three patients who sustained patella tendon injuries in infected total knee arthroplasties following the use of a static cement spacer at first-stage knee revision. The patella tendon injuries resulted in significant compromise to wound healing and knee stability requiring multiple surgeries. The mid-term function was poor with an Oxford score at 24 months ranging from 12–20. Based on our experience, we advise caution in the use of static cement spacer blocks. If they are to be used, we recommend that they should be keyed in the bone to prevent patella tendon injuries

Introduction. Knee injuries are common amongst footballers. The aim of this study was to establish frequency and variation of knee injuries within one English Premier League (EPL) professional football club over two seasons, to assess number of days missed due to injury, and analyse current treatment regimen for each injury type. Method. Data was collected prospectively for injuries suffered by players between 2009 and 2011, spanning two EPL seasons at one EPL club. Demographics were recorded along with various factors influencing injury, including playing surface, pitch condition, dominant side, type of injury, ability to continue playing, and mechanism of injury. Time taken for return to play, and treatment received was recorded. Results. 35 injuries occurred that were severe enough to cause players to miss at least one competitive match. The commonest injury was to the medial collateral ligament (MCL) in 34%. Patella tendon injuries were seen in 29%, other injuries included meniscus tears, ACL ruptures, and osteochondral defects. All grade II MCL Injuries received sclerosant injections. 40% of patella tendon injuries were given plasma-rich protein (PRP) injections, and 30% underwent surgery. The mean recovery time following MCL and patella tendon injuries was 44 days and 77 days respectively. 60% of injuries were sustained during training and 40% were suffered in competitive games. 26% were recurring injuries, recurrent meniscus and patella tendon injuries took twice as long to recover compared to the initial injury. Conclusion. Our findings suggest that MCL and patella tendon injuries are the most common knee injuries amongst professional footballers and that meniscus tears and ligament ruptures are relatively rare in comparison. Injuries appear to occur more frequently during training. A high proportion of injuries in the study received injection therapy in the form of PRP or sclerosant. The study suggests recurrent injuries can prolong recovery two-fold

Introduction. Flexor tendon injuries are quite common injuries. They can result in persisting functional deficit if not repaired and appropriately rehabilitated. We look at flexor tendon injuries over a period of 1 year and re-audited three years later. Method. We audited all flexor tendon injuries that were treated at our institution and repeated the same audit three years after. We looked at various aspects of the injuries including the site injured, the zone of injury, other structures injured, the type of repair and material used as well as the rehabilitation regime. Results. The initial audit had 43 patients, 83% male, 55% unemployed with 85 tendon injuries. There were 35% zone 5 injuries with 34% repaired in <24hrs with modified Kessler core 3.0 prolene sutures and 6.0 prolene peripheral sutures. The rupture rate was 3% and the infection rate was 1%. A re-audited was done 3 years later, over the same time period, there were 69 patients, 83% male, 1% unemployed with 102 tendon injuries. There were 40% zone 2 injuries with 43% repaired with modified Kessler core 3.0 prolene sutures and 6.0 prolene peripheral sutures. Rupture rate was 9% and infection rate was 1% and 10% median nerve injury. All injuries were rehabilitated using the Belfast regime. Discussion and Conclusion. Flexor tendon injuries are frequently occurring injuries and require a careful and meticulous attention to detail, relative to repair, to achieve the most effective recovery. We found that over a three year period that the zone of injury in the cohort of patients in our region had changed, as well as the unemployment rate. Other parameters were generally similar. We conclude that treatment of flexor tendon injuries should undergo the audit cycle to ensure that best practice is achieved and maintained

Increased use of locking volar plates for distal radius fractures led to a number of reports in literature of flexor tendon injuries from impingement and attrition against hardware. Repair of the pronator quadratus is critical in preventing tendon injury. We present a pronator quadratus sparing approach to the distal radius. The senior author has used a pronator quadratus sparing lateral pillar approach for for the past five years. A lateral incision is used over the radial styloid. The first dorsal compartment is released and APL and EPB tendons retracted. The underlying brachio-radialis tendon and insertion fascia is split and the palmar portion elevated off the distal radius with the pronator quadratus as a single contiguous sheet. The distal edge of the pronator quadratus is elevated from the wrist capsule by sharp dissection. The radial artery is protected by the retracted tissue. Repair of the brachio-radialis tendon and insertion fascia is much more robust than that of the pronator quadratus covering the entire plate. Since 2004, the senior author has used the pronator quadratus sparing approach for volar plating of the distal radius, in 183 cases. At last follow-up there were no instances of flexor tendon injury, which was considered to be one of the outcome measures and end-points. There was no impingement in the first dorsal compartment, except in two cases of lateral pillar hardware impingement from additional lateral pillar plate fixation through the same approach. Nine cases had minor persistent superficial radial nerve parasthesia. One case had a superficial wound infection requiring drainage. The repaired pronator quadratus formed a barrier protecting the plate. The infection was aggressively treated and the plate left in situ for three months till fracture union. Cultures from the retrieved plate showed no organisms. Another implant had two of the locking screws back out. The pronator quadratus fascia was tented with an underlying haematoma. The fascia however only showed minimum screw penetration and no flexor tendon injury. Average wrist dorsiflexion was 72 deg and palmar flexion 65 deg. Average pronation was 81 deg and average supination 69 deg. Supination range was slow to recover in younger patients. One explanation could be the tight pronator quadratus repair. Average PRWE and DASH scores were 19. The quadratus sparing approach to the volar distal radius is easy to perform and protects the flexor tendons at the wrist. Cases demonstrated that an intact pronator quadratus can act as an effective barrier to prominent hardware and superficial infection. Supination range may be reduced by this approach due to a tight repair, though a palmar DRUJ capsule contracture may also be an explanation

Introduction. Stem cells are widely known in the state of the art of cell-based therapies. Recently, ADSCs are becoming a popular resource of adult stem cells across different fields, and latest publications show its wide application for the treatment of soft tissue injuries like tendon injuries, which represent a high percentage of the consultations in orthopaedic practitioners. Molecular-based therapies and local deliveries are necessary for an effective treatment of chronic tendon injuries. In this study, human ADSCs were selected to investigate its differentiation potential into the tendon phenotype. Customised cell culture media was used as the differentiation factor. Materials and Methods. In the present study, ADSCs were used in passage 3 to ensure pluripotency in vitro. Using the customised cell culture media, its time, concentration and frequency of refreshment effects were investigated. On the selected time points different techniques were performed: 1,) cells were harvested, and messenger RNA (mRNA) was examined by Real Time Polymerase Chain Reaction (RT-PCR), analysing the expression of common tendon and extracellular matrix (ECM) markers. Protein expression was determined by Western Blotting. 2) Collagen content was analysed by tissue digestion and colorimetric techniques. 3) Deoxyribonucleic Acid (DNA) was stained, and fluorescent imaging was used to characterise nuclear roundness. 4) Metabolic activity of the cultures was assessed using CellTiter 96® Aqueous One Solution (MTS). 5) Cell proliferation was evaluated using CyQuant® Cell Proliferation Assay. Results. In this work, we systematically evaluated the doses and time effect of the customised media on the differentiation potential of ADSCs. Our results showed significant differences in the cell performance between the conditions investigated. Interestingly, ADSCs presented enhanced tendon marker expression (mRNA and protein level) and collagen content. The different tendon and ECM markers analysed by RT-PCR showed doses and time-dependent effect, establishing a connection with. its role in the tissue. We believe this could offer a possible regenerative treatment without overstimulation. Despite the condition, ADSCs presented 95%–100% viability and proliferation values, demonstrating the non-toxic effect of the media. Conclusion. This study contributes to the knowledge of differentiation potential of ADSCs in tendon repair. Furthermore, the tendon phenotype generated in the 2D cultures changes when different variables are investigated. Knowing the molecular basis and conformations of the tendon phenotype is key in tendon research. Hence we believe these results can show a new paradigm in tendon repair, making possible to select more suitable treatments depending on the status of the injury on the patients. Acknowledgements. This work was supported by Rosetrees Trust, Arthritis Research UK and the Universityof East Anglia

Introduction. Cell-based tendon engineering is an attractive alternative therapeutic approach to established treatments of tendon injuries. Numerous cell types are promising source of tendon engineering; however, there are certain disadvantages for each cell type. Interestingly, dermal fibroblasts (DFs) are able to transdifferentiate into other cell types, they are widely distributed in dermis and easy to harvest and isolate. Furthermore, pilot clinical studies suggested a promising therapeutic potential of autologous DFs for discorded tendons (Connell et al., 2009&2011), but the underlining repair mechanisms remain unclarified. To investigate tenogenic differentiation process in great detail, we have previously established a three-dimensional (3D) cell sheet model, comprising of three consecutive step (expansion, stimulation and maturation) leading to the formation of 3D tendon-like tube (Hsieh et al., 2018; Yan et al., 2020). Hence, the aim of this study was to carry out pilot examination of the tenogenic potential of human DFs (hDFs) by implementing the 3D cell sheet model. Methods. hDFs (company purchased, n=2), hBMSCs (human bone marrow mesenchymal stem cells, n=1) and hTSPCs (human tendon stem/progenitor cells, n=1) were used and subjected to the 3D model. In 2D culture, semi-qPCR was performed to validate the expression of DF markers in hDFs, namely NTN1, PDPN and CD26 for papillary dermis layer, and PPARG, ACTA2 and CD36 for reticular dermis layer). FACS analysis and immunofluorescence were employed to validate expression of CD73, CD90, CD105 and vimentin (mesenchyme marker), respectively. After harvesting the 3D cell sheets, wet weigh measurements, H&E and collagen type I stainings, and semi-qPCR for Scleraxis and tenomodulin were executed. Results. Semi-qPCR of DF markers validated the dermal origin of both donor-derived hDFs; however, the data suggested that donor 1 was mixed cell pool of papillary and reticular dermal cells, whilst donor 2 was reticular dermal cells. In FACS analysis, the expression levels of CD73 and CD90 were comparable among all cell types. For CD105, ca. 20% of the cells were negative in both hDF and hTSPC cultures, but only 2% in hBMSCs. As expected, all three cell types were vimentin-positive. 3D cell sheet formation was successful for all cell type. Interestingly, the hDF cell sheets were thicker and ca. 2-fold heavier than that of hBMSCs and hTSPCs. Next, H&E and collagen I analyses revealed higher cellularity as well as higher collagen I deposition in the hDF sheets compared to the other two cell types. Last, semi-qPCR for Scleraxis and tenomodulin suggested upregulation of both genes in hDF and hTSPC sheets versus 2D culture. Discussion. Our pilot data suggests that hDFs perform well and even exceed hBMSCs and hTSPCs in the 3D model in terms of size, cellularity and collagen I expression. However, increase of cohort size and further detailed molecular and histomorphometric analyses are necessary to conclude on the promising tenogenic potential of hDFs

Tenomodulin (Tnmd) is the best known mature tendon factor for tendon and ligament tissues with reported important regulatory roles1. In addition, Tnmd C-terminal cysteine-rich domain has been descibed to exert anti-angiogenic functions in in vitro angiogenic assays as well as in vivo models of tendon injury and age-associated cardiac valve diseases1, 2. Interestingly, Tnmd expresson in the intervertebral disc (IVD), which is normally avascular tissue, has been also suggested3. Hence, the purpose of this study was first, to map the exact expression pattern of Tnmd during IVD development and aging and second, by implementing Tnmd-knockout mouse model, to examine if Tnmd plays a role in IVD homeostasis. Histological analyses (hematoxylin/eosin, Safranin O, CD31 for endothelium, TUNEL for apoptosis and type X collagen and Runx2 for hypetrophy) were performed on Tnmd −/−, Tnmd −/− and chondromodulin I Chmd 1 −/− (Tnmd only homolog) double knockout and wild type mice WT (n = three to five) to examine IVD degeneration. Real time PCR was implemented to explore gene expression chnages in annulus fibrous (AF) between Tnmd −/− and WT mice. In addition, outer AF (OAF) cells were isolated from both genotypes to further determine cellular phenotype and assess effects on co-culture with human umbical vein endothelial cells (HUVECs). Statistical differences between two groups were determined with t-test. In multiple comparisons, one-way ANOVA was followed by Bonferroni post-hoc correction. Tnmd was expressed in a temporal manner in OAF and to very low extent in NP. Tnmd −/− mice exhibited more rapid progression of age-related IVD degeneration. These signs included smaller collagen fibril diameter, reduced multiple IVD- and tendon/ligament-related gene expression, induced angiogenesis and inflamatory cell infiltration in OAF as well as more hypertrophic-like chondrocytes in the NP. In addition, Tnmd−/− Chm1 −/− mice displayes not only accelerated IVD phenotpye, but also ectopic bone formation in the IVD. Lastly, the abscence of Tnmd in OAF-derived cells significantly promoted HUVECs migratory capacity. These findings provide clear evidence that Tnmd plays a critical role in IVD homeostasis

MIS (minimally invasive surgery) aims to improve cosmesis and facilitate early recovery by using a small skin incision with minimal soft tissue disruption. When using MIS in the forefoot, there is concern about neurovascular and tendon damage and cutaneous burns. The aim of this anatomical study was to identify the structures at risk with the proposed MIS techniques and to determine the frequency of iatrogenic injury. Materials and Methods. 10 paired normal cadaver feet were used. All procedures were performed using a mini C-arm in a cadaveric lab by 2 surgeons: 1 consultant who has attended a cadaveric MIS course but does not perform MIS in his regular practice (8 feet), and 1 registrar who was supervised by the same consultant (2 feet). In each foot, the surgeon performed a lateral release, a MICA (minimally invasive chevron and Akin) procedure for the correction of hallux valgus, and a minimally invasive DMO (distal metatarsal extra-articular osteotomy) procedure. Each foot was then dissected and photographed to identify any neurovascular or tendon injury. Results. The dorsal medial cutaneous and the plantar interdigital nerves were intact in all specimens. There was no obvious damage to the arterial plexus supplying the first metatarsal head. No flexor or extensor tendon injuries were identified. There is a significant learning curve to performing the osteotomy cuts in the desired plane. In the DMO, the dissection also revealed some intact soft tissue at the osteotomy site indicating that the metatarsal heads were not truly floating. Discussion. Although there has been concern regarding neurovascular and tendon injury, our findings indicate minimal risk, which is consistent with reports in the literature. This study also reflects the learning curve. Conclusion. We suggest that training on cadaveric specimens may be advantageous, particularly, with regard to the plane of the osteotomy

Autologous cell therapy using stem cells and progenitor cells is considered to be a popular approach in regenerative medicine for the repair and regeneration of tissue and organs. In orthopaedic practice, autologous cell therapy has become a major focus, particularly, as a feasible treatment for tendon injury. Tendons are dense connective tissue that bridge bone to muscle and transmit forces between muscle and bone to maintain mechanical movement. Tendons are poorly vascularised and have very little capacity to self-regenerate. Degeneration of tendon is often caused by injury. The pathogenesis of tendon injury, commonly known as tendinosis, is not an inflammatory condition but is secondary to degenerative changes, including disruption of the collagen matrix, calcification, vascularisation and adipogenesis. The aetiology of tendinosis is considered to be multifactorial and the pathogenesis is still unclear. Intrinsic factors such as a lack of blood and nutrition supply and extrinsic factors such as acute trauma and overuse injury caused by repetitive strain, have been implicated as contributors to the pathogenesis of tendinosis. More recent studies suggest that programmed tendon cell death (tenocyte apoptosis) may play a major role in the development of tendinosis. Such cellular abnormalities may influence the capacity of tendon to maintain its integrity. Traditional treatments such as anti-inflammatory drugs, steroid injections and physiotherapy are aimed at symptom relief and do not address the underlying pathological changes of degeneration. Here, we propose that autologous cell therapy may be an innovative and promising treatment for tendon injury. We will present evidence that suggest that autologous tendon cell therapy may be feasible to repair and regenerate tendon. We will also present data summarising the preclinical evaluation of autologous tendon cell therapy in animal models and the safety and tolerability of autologous tendon cell therapy in humans in studies, which are currently conducted at the Centre for Orthopaedic Research at the University of Western Australia

Purpose of the study: We report an unusual complication of patella tendon rupture that occurred secondary to the use of static cement spacer blocks in a series of three patients undergoing staged revision total knee arthroplasty (TKA) for infection. Methods and results: 3 male patients developed patella tendon injury secondary to anterior subluxation of static cement spacer blocks used at the first of a two-stage revision procedure for infected TKA. Average patient age was 70 years. The interval between the 1st and the 2nd stages varied between 3.5 to 24 months. At the second stage, it was observed that the patella tendon was completely severed and irreparable in one case, whereas it was partially injured and repairable in the other two cases. In the case with irreparable tendon injury, stable joint reconstruction could not be achieved at the second stage and ultimately resulted in knee arthrodesis. In the other two cases, 2nd stage revision was performed using hinged revision knee components and the tendon injury was repaired and protected with a circlage wire. None of the patients were satisfied with their outcome at the final review. Conclusion: This is the first report in the literature reporting the complication of patella tendon rupture secondary to the use of static cement spacer blocks in staged revision knee arthroplasty. The injury can either be repairable or irreparable. The functional outcome and satisfaction is not good after the salvage procedures. Therefore, we recommend that these spacer blocks should not be used in revision knee arthroplasty

Introduction. Adult tendon injuries occur very frequently, but injured tendon heals very slowly and the mechanisms of the slow-healing response to injury are still largely unknown. Currently, the main barrier is our insufficient understanding of the mechanisms responsible for homeostasis, regeneration and repair of adult tendon. This gap in knowledge translates to a lack of experimental models. Therefore, using the combination of state-of-the-art genetic approaches, we have established novel cell biological tools to advance the understanding of tendon biology. Materials and Methods. Adult mouse tendon progenitor lines and Adult mouse tenocyte lines: Primary adult tenocytes were isolated from Achilles tendon in Scleraxis(fl/fl)/Scleraxis-GFP/p21(−/−) mice, then CD90.2- and subsequent Sca1-positive cells were sorted by Flow Cytometry. Then Scleraxis-null progenitor lines were generated by the treatment of those cells with adenovirus-Cre. Adult Scleraxis(+/+) and Scleraxis-null tenocyte lines were also generated from Scleraxis(fl/fl)/Scleraxis-GFP/p21(−/−) mice. To establish Scleraxis-Flag overexpressing tenocyte lines, Scleraxis and Flag-tag fusion-protein expression construct was generated and transfected into Scleraxis-null tenocytes (Scleraxis transgenic mouse strains were provided by Dr Ronen Schweitzer). Scleraxis antibody: DNA coding mouse Scleraxis residues were obtained by PCR, then the recombinant protein was expressed, immunized in rabbits, and an affinity-purified antibody was generated. Results. Established parental progenitor lines highly expressed Sca1 (98.9%), CD90.2 (97.3%), and CD44 (99.8%) and were almost negative for ScxGFP (2.3%). Interestingly, Scleraxis-null progenitors showed significantly increased clonogenicity. Furthermore, when stimulated toward mesenchymal lineages, Scleraxis-null progenitors enhanced differentiation into chondrocytes. Our Scleraxis antibody reacted with lysates from cells expressing Scleraxis-Flag fusion proteins (∼30 kDa), whereas it did not react with Scleraxis-null cells by Western analysis. Immunofluorescence analysis of adult mouse Achilles tendons further confirmed intense Scleraxis protein expression in wild-type tenocytes, whereas considerably decreased expression of Scleraxis was evident in Cre-treated Scleraxis(fl/fl) tenocytes. Discussion. These novel tools will be the promising resources to get an insight into molecular framework for Scleraxis in adult tendons. It is anticipated that the establishment of experimental models using these resources will fill major gaps in the current knowledge of adult tendon biology and will facilitate development of novel strategies to treat adult tendon injury

Muscle and tendon have an adaptive, symbiotic biomechanical relationship that is drastically altered following acute tendon injury. Such injuries, like Achilles tendon rupture (ATR), do not only lead to impairments in the resultant tendinous tissue, but also to irrecoverable atrophy in the connected muscle in series. As a result, a new relationship between muscle and tendon is established after ATR, leading to lasting functional deficits in the lower limb. It remains unclear how these develop, particularly since this imbalance may be influenced by the dependent relationship of the two tissues to each other. A further confounding factor is that tendon and muscle tissues adapt on different time scales in response to mechanical loading, such as those introduced during rehabilitation. Thus, it is warranted to perform assessments not only of the overall muscle-tendon unit, but also its constituent tissues. This presentation will discuss findings from both short-term and long-term follow-ups of ATR patients, with a focus on the recovery of gait and changes in the muscle-tendon unit tissues following ATR repair. Both the influence of the rehabilitation process and suggestions for future research directions will be additionally presented

A rotator cuff tear is one of the most common traumatic and degenerative tendon injuries resulting in over 4.5 million physician visits in the US alone. Functional restoration of rotator cuff defects usually requires surgical repair, estimated at 300,000 cased in the US annually. However, postoperative retear of repaired tendons ranges from 20% in small to medium tears to over 90% in large and massive tears. Recently, augmentation with grafting materials to strengthen a reparable tear or to bridge an unrepairable defect has become a common and attractive strategy to reduce the retear rate, especially for large or massive tears. Current graft materials, however, have encountered great challenges in achieving these goals. To meet these challenges, we have developed an engineered tendon with layered tendon-fibrocartilage-bone composite (TFBC) from patellar-tibia unit revitalized by seeding bone marrow derived stem cells (BMDSCs) within the slices, and then reassembled to an engineered tendon. Both in vitro and in vivo results have shown that engineered TFBC enhance the biomechanical strength and biological healing using canine model

The April 2023 Wrist & Hand Roundup³⁶⁰ looks at: MRI-based classification for acute scaphoid injuries: the OxSMART; Deep learning for detection of scaphoid fractures?; Ulnar shortening osteotomy in adolescents; Cost-utility analysis of thumb carpometacarpal resection arthroplasty; Arthritis of the wrist following scaphoid fracture nonunion; Extensor hood injuries in elite boxers; Risk factors for reoperation after flexor tendon repair; Nonoperative versus operative treatment for displaced finger metacarpal shaft fractures.

Injuries to the quadriceps muscle group are common in athletes performing high-speed running and kicking sports. The complex anatomy of the rectus femoris puts it at greatest risk of injury. There is variability in prognosis in the literature, with reinjury rates as high as 67% in the severe graded proximal tear. Studies have highlighted that athletes can reinjure after nonoperative management, and some benefit may be derived from surgical repair to restore function and return to sport (RTS). This injury is potentially career-threatening in the elite-level athlete, and we aim to highlight the key recent literature on interventions to restore strength and function to allow early RTS while reducing the risk of injury recurrence. This article reviews the optimal diagnostic strategies and classification of quadriceps injuries. We highlight the unique anatomy of each injury on MRI and the outcomes of both nonoperative and operative treatment, providing an evidence-based management framework for athletes.

Cite this article: Bone Joint J 2023;105-B(12):1244–1251.

Aims: To clarify correlation between magnetic resonance imaging (MRI) and pathology of pain in posterior aspect of the ankle in ballet dancers. Methods: Twenty feet of þfteen patients, who underwent surgery with the average age of 19.2 years, were retrospectively analyzed. They were diagnosed as ßexor hallucis longus (FHL) tendon injury or posterior ankle impingement (PAI) syndrome mainly based on physical signs. MRI þndings of FHL tendon were classiþed with the classiþcation of posterior tibial tendon dysfunction presented by Conti et al., and were compared with macroscopic changes of the tendon. FHL injuries were classiþed as follows; paratendinitis as grade-1, superþcial injury (< 1/2 thickness) as grade-2, and deep injury as grade-3. MRI þndings of PAI syndrome were also compared to surgical and histological þndings. Results: Correlation of FHL tendon injury with MRI þndings was presented on the table. There was a case with a ganglion cyst of FHL tendon presented on MRI. There were, however, two cases with ganglions on þbro-osseous tunnel MRI could not reveal. In four feet of three patients, bone marrow edema in os trigonum or posterior part of the talus was observed. Conclusion: MRI was useful to investigate the pathology of pain in posterior aspect of the ankle

Tendon injuries constitute a major healthcare burden owing to the limited healing ability of these tissues and the poor clinical outcomes of surgical repair treatments. Recent advances in tendon tissue engineering (TTE) strategies, particularly through the use of biotextile technologies, hold great promise toward the generation of artificial living tendon constructs. We have previously developed a braided construct based on suture threads coated with gelMA:alginate hydrogel encapsulating human tendon cells. These cell-laden composite fibers enabled the replication of cell and tissue-level properties simultaneously. Based on this concept, in this study we explored the use of platelet lysate (PL), a pool of supra-physiological concentrations of growth factors (GFs), to generate a hydrogel layer, which is envisioned to act as a depot of therapeutic factors to induce tenogenic differentiation of encapsulated human adipose stem cells (hASCs). For this purpose, commercially available suture threads were first embedded in a thrombin solution and then incubated in PL containing hASCs. Herein, thrombin induces the gelation of PL and consequent hydrogel formation. After coating suture threads with the mixture of PL-ASCs, cells were found to be viable and homogeneously distributed along the fibers. Strikingly, hASCs encapsulated within the PL hydrogel layer around the suture thread were able to sense chemotactic factors present in PL and to establish connections between adjacent independent fibers, suggesting a tremendous potential of PL cell-laden hydrogel fibers as building blocks in the development of living constructs aimed at tendon repair applications

Unresolved inflammatory processes in tendon healing have been related to the progression of tendinopathies. Thus, the management of tendon injuries may rely on cell-based strategies to identify and modulate tendon inflammatory cues. Pulsed electromagnetic field (PEMF) has been approved by FDA for orthopedics therapies and has been related to a reduction in pain and to improve healing. However, the influence of PEMF in tendon healing remains largely unknown. Human tendon resident cells (hTDCs) were cultured in an inflammatory environment induced by exogenous supplementation of IL-1β and their response assessed after exposure to different PEMF treatments. This study demonstrates that IL-1β induced up-regulation of pro-inflammatory factors (IL-6 and TNFα) and extracellular matrix components (MMP−1, −2, −3) whereas reduces the expression of TIMP-1, suggesting IL-1β as a candidate inflammation model to study hTDCs response to inflammation cues. Moreover, in both homeostatic and inflammatory environments, hTDCs respond differently to PEMF treatment suggesting that cells are sensitive to magnetic field parameters such as strength (1.5 – 5mT), frequency (5–17Hz) and duration (10–50% duty cycle, dc). Among the conditions studied, PEMF treatment with 4mT/5Hz/50%dc suppresses the inflammatory response of hTDCs to the IL-1β stimulation, as evidenced by the decreases amount of IL-6, TNFα and downregulation of MMP-1, −2, −3 and COX-2, IL-8, IL-6, TNFα genes. These results demonstrate the potential of PEMF, in particular 4mT/5Hz/50%dc PEMF in treating tendon inflammation suppressing the inflammatory stimulation induced by IL-1β, which may be beneficial for tendon healing strategies

Aims

The aim of this systematic review and meta-analysis was to gather epidemiological information on selected musculoskeletal injuries and to provide pooled injury-specific incidence rates.

Tendon injuries are common and current therapies often are unsuccessful. Cell-based therapy using mesenchymal stem cells (MSCs) seems to be the most promising approach to heal tendon. Moreover, providing safe and regulated cell therapy products to patients requires adherence to good manufacturing practices (GMP). Adipose-derived stem cells (n=4) were cultured in 6-well plates coated with type-I collagen in a chemically defined serum-free medium (SF) or a xenogenic-free human pooled platelet lysate medium (hPL). At passage 4, ASCs were induced to tendon lineage for 14 days using 100ng/ml CTGF, 10ng/ml TGFβ3, 50ng/ml BMP12 and 50µg/ml ascorbic acid in the SF (SF-TENO) or in the hPL (hPL-TENO) medium. Cells cultured without any supplements are used as control. Morphological appearance, cell viability and FACS were performed in undifferentiated cells to evaluate the xenogenic-free culture conditions; the gene and protein expression were performed by RT-PCR and immunofluorescence to evaluate to expression of stem cell- and tendon-related markers upon cell differentiation. SF-CTRL and hPL-CTRL showed similar viability and MSC's surface proteins and expressed the stemness markers NANOG, OCT4 and Ki67. Moreover, both SF-TENO and hPL-TENO expressed significant higher levels of SCX, COL1A1, COL3A1, COMP, MMP3 and MMP13 genes already at 3d (p<0.05) respect to CTRLs. Scleraxis and collagen were also detected in both SF-TENO and hPL-TENO at protein level in higher amount than CTRLs. In conclusion, ASCs exposed to CTGF, BMP12, TGFb3 and AA in both serum and xenogenic-free media possess similar tenogenic differentiation ability moving forward the GMP-compliant approaches for the clinical use of ASCs

Intra-synovial tendon injuries affect compressed tendon within a synovial environment (eg Rotator cuff tears of the shoulder) and frequently demonstrate ‘failed healing'. Current therapeutic methods for tendon tears (intra-synovial corticosteroid medication and surgical debridement) offer poor outcomes and new strategies for enhancing repair are needed. We have therefore evaluated two different approaches involving the use of mesenchymal stem cells and scaffolds. Bone marrow- and synovial-derived stem cells were capable of adhering to cut surfaces of tendon in vitro and modulating the release of extracellular matrix into the media. However, when administered in vivo into the digital flexor tendon sheath in naturally-occurring deep digital flexor tendon tears in horses and in an experimental model in sheep, neither cell type was capable of healing the tendon defect. Superparamagnetic iron oxide particle labelling of the implanted cells imaged using MRI and histologically revealed that cells only engraft into the synovium. In contrast a non-cellularised bilayered electrospun and woven polydioxanone scaffold, when used in the same experimental sheep model via a modified open approach and sutured over the created defect resulted in no local or systemic signs of excessive inflammation 3 months after implantation. All the tendon lesions healed with only a mild local inflammatory reaction and minimal-to-mild adhesion formation. Significant proliferative fibroblast infiltration was observed within and immediately adjacent to the implanted scaffold. The cellular infiltrate was accompanied by an extensive network of new blood vessel formation within the new tissue. In conclusion, the use of a scaffold to cover the defect appears to be a more successful strategy to repair intra-synovial tendon defects than intra-synovially injected mesenchymal stem cells. It remains to be tested whether the combination of the two techniques might offer an even better healing response

Aims

The primary objective of this study was to develop a validated classification system for assessing iatrogenic bone trauma and soft-tissue injury during total hip arthroplasty (THA). The secondary objective was to compare macroscopic bone trauma and soft-tissues injury in conventional THA (CO THA) versus robotic arm-assisted THA (RO THA) using this classification system.

There is a growing socio-economic need (i.e. “ageing society”) for effective and reproducible strategies to repair musculoskeletal tissue. In particular, acute tendon injury and chronic tendinopathies remain clinically challenging and novel treatment modalities are urgently needed. Tendons resemble a connective tissue rich in highly organized collagen fibers, displaying a remarkably high tensile strength. However, partly due to the low number of cells and their more or less avascular nature tendons heal relatively slowly. Ultimately, tendon regeneration encompasses the full restoration of the biological, biochemical and biomechanical properties, which are often impaired by endogenous healing cascades. Usually, a connective scar tissue forms at the injury site and the replaced tissue does not function adequately at high strain levels, increasing the chance of re-rupture. Despite significant advancements in tissue regeneration and engineering strategies, the clinical impact for the regeneration of tendon remains limited. For the development of novel methods to repair tendons we need to pin down the molecular and cellular mechanisms amenable to modulate endogenous (or exogenous) cell behaviour towards functional tissue regeneration. By comparing the gene expression profile of Achilles tendon tissue harvested from young-mature and old mice we demonstrate profound changes in the expression of ECM-related proteins and a previously unknown role of Secreted protein acidic and rich in cysteine (Sparc; also known as BM-40 or osteonectin) in tendons. Sparc levels in tendons are critical for proper collagen fibril maturation and its age-related decrease, together with a change in ECM properties potentially drives adipogenic differentiation of tendon stem and progenitor cells (TDSPCs) and consequently lipid accretion in tendons. Generally, the fate of stem/ progenitor cells is largely determined by stimuli from the stem cell niche. In tendons, we describe a novel cellular barrier, most likely preventing the leakage of blood-borne products into the tendon proper. We propose that this “blood-tendon barrier” is part of the stem cell niche in tendons controlling TDSCP fate, preventing erroneous differentiation. By investigating the developmental programs driving tendon tissue formation and on the other hand the mechanisms contributing to the senescence of tendons, ultimately resulting in decreased quality of tendons in the elderly, novel targets for clinical intervention potentially can be discovered

Summary. Our results prove that Demineralised Cortical Bone (DCB) can be used as biological tendon graft substitute, combined with correct surgical technique and the use of suture bone anchor early mobilisation can be achieved. Introduction. Surgical repair of tendon injuries aims to restore length, mechanical strength and function. In severe injuries with loss of tendon substance a tendon graft or a substitute is usually used to restore functional length. This is usually associated with donor site morbidity, host tissue reactions and lack of remodelling of the synthetic substitutes which may result in suboptimal outcome. In this study we hypothesise that DCB present in biological tendon environment with early mobilisation and appropriate tension will result in remodelling of the DCB into ligament tissue rather that ossification of the DCB at traditional expected. Our preparatory cadaveric study (abstract submitted to CORS 2013) showed that the repair model used in this animal study has sufficient mechanical strength needed for this animal study. Methods. 6 mature female sheep undergone surgical resection of the distal 1 cm of the right patellar tendon and osteotomy of patellar tendon attachment at the tibial tuberosity under general anaesthesia. Repair was done using DCB with 2 suture bone anchor. Animals were allowed immediate mobilisation after surgery and were sacrificed at 12 weeks. The force passing through the operated and non-operated legs was assessed preoperatively and at week 3, week 6, week 9 and week 12 bay walking the animals over a force plate. Radiographs were taken immediately after euthanasia, the Patella-Tendon-tibia constructs were retrieved and pQCT scan was done. Histological analysis included tenocytes and chondrocytes cell counts, semi-quantitative scoring of the neo-enthesis and polarised microscopy. Result. In this study, none of the retrieved specimens showed any evidence of ossification of the DCB as proved by the pQCT analysis. One animal failed to show satisfactory progress after week 3, X-rays showed patella alta, on specimen retrieval no damage to the DCB was found, sutures and stitches were intact and no evidence of anchor pullout was found. Force plate analysis of the other 5 animals showed satisfactory progression over time with 44% functional weight bearing at week 3 progressing to 79% at week 12. There was full range of movement of the stifle joint after 12 weeks. Histological analysis proved formation of neo-enthesis with evidence of cellulisation, vascularisation and remodelling of the collagen leading to ligamentisation of the DCB. Discussion. Surgical reconstruction of damaged tendons is technically challenging, patellar tendon injuries presents even more challenging situation as it involves weight bearing joint. It is generally accepted that a period of immobilisation with passive range of movement exercises and protected weight bearing for up to 6 weeks post operatively is usually advised. Some surgeons use offloading metal wire to protect the repair for 6 weeks involving second surgical procedure to remove the wire. Demineralised bone is usually used in orthopaedics to utilise its osteogenic properties as bone graft substitute and to enhance osteogenesis in load bearing situations. In our study we explored a potential new use of the demineralised bone as tendon graft substitute, it acts as collagen scaffold allowing host cells to remodel its fibres into ligament like structure

Summary Statement. Transportation media and injection protocol have implications for the viability of MSCs used for intra-lesional treatment of tendon injuries. Every effort should be made to implant cells within 24h of laboratory re-suspension, using a needle bore larger than 21G. Introduction. Intra-lesional implantation of autologous mesenchymal stem cells (MSCs) has resulted in significant improvements in tendon healing in experimental animal models. Intra-tendinous injection of MSCs into naturally-occurring equine tendon injuries has been shown to be both safe and efficacious. 1. and these protocols can assist in the translation to the human. Efficient transfer of cells from the laboratory into the tissue requires well validated techniques for transportation and implantation. The aim of this study was to determine the influence of transport media and injection procedure on cellular damage. Methods. Bone marrow derived MSCs (n=3 horses) were prepared and expanded as described. 1. Cells were suspended in 0.5mL of experimental media at 2.5×10. 6. cells/mL and stored at 4–8°C for 24, 48 and 72h. Experimental media were: bone marrow aspirate (BMA); cell culture media (DMEM); equine serum; equine plasma; isotonic saline; hyaluronic acid (HA); platelet-rich plasma (PRP) and frozen (in 90% serum, 10% DMSO). In addition, cells suspended in DMEM were injected through a 19G, 21G or 23G needle and cell viability, proliferation and apoptosis were analysed using trypan blue, alamarBlue® and Annexin-V assays respectively. Results. There was no significant difference in overall viability at 24h storage in any media, however cell death was most rapid when cells were suspended in BMA, PRP and serum. Viability was greatest at all time points when cells were frozen. Cell proliferation was similar following storage for 24 and 72h in all media, except for 24h in serum, wherein proliferation was enhanced. There was no significant decrease in viability immediately following injection but 21G and 23G needles resulted in a marked increase in apoptotic cells compared to 19G and non-injected controls after 24h when re-seeded for culture. All needle gauges resulted in a marked decrease in cell proliferation immediately post-injection with recovery by 2h post-injection. Conclusions. Although there is, as yet, no guidance on the storage of MSCs, it has been suggested that in vitro storage of hematopoietic stem or progenitor cells should not exceed 2h. 2. This suggestion is impractical both for current equine therapeutic use and when considering future, commercial applications of MSC therapy in humans, because of the necessity to transport the cells from a remote licensed facility to the clinic. Our data suggest an upper limit of 24h for transportation, whereas for transportation of greater duration than 24h, cells should ideally be frozen, to maximise viability. An increased number of dead cells potentially has two adverse consequences; first, a reduced efficacy and second, the presence of dead cell debris may induce inflammation. While the first can be compensated for by higher cell numbers, this compounds the problems of the second. This study reinforces the importance of limiting the delay between preparation of cells for shipment from the laboratory and implantation in the clinic and suggests that an injection procedure while not causing immediate cell death can cause significant delayed cell death if small bore needles are used

Summary. Silver nanoparticles improve the tensile property of the repaired Achilles tendon by modulating the synthesis and deposition of collagen. This makes silver nanoparticles a potential drug for tendon healing process with less undesirable side effect. Introduction. Tendon injury is a common injury that usually takes a long time to fully recover and often lead to problems of joint stiffness and re-rupture due to tissue adhesions and scarring on the repaired tendon respectively. Recently, it has been proven that silver nanoparticles (AgNPs) are capable of regenerating skin tissue with minimal scarring and comparable tensile property to normal skin. Hence, it is hypothesised that AgNPs could also improve the healing in tendon injury as both tissues are predominating with fibroblasts. The objective of this study is to look at the in vitro response of primary tenocytes to AgNPs and to investigate the mechanical and histological outcome in vivo. Methods and Materials. Primary tenocytes were harvested from 4 weeks old Sprague Dawley rat. 1.5×10. 4. cells per cm. 2. were seeded in triplicate for BrdU incorporation assay and Sirius red/ fast green staining to study the proliferation and collagen synthesis respectively. In vivo rat Achilles tendon injury model was used to investigate the effect of AgNPs to tendon regeneration. Briefly, the Achilles tendon was transected at 0.5cm from its insertion. The wound was either treated with 1mM AgNPs every 5 days or left untreated as the control. Skin incision was done without transecting the tendon in the sham group. The tendons were harvested on day 42 post operation. Tensile test and immunohistological staining on 7μm cryosections were performed to assess the mechanical property and biological events in healing respectively. SHG imaging was used to determine the collagen fibre orientation and abundance. Results. In vitro BrdU incorporation and Sirius red fast green assay suggested that AgNPs promoted the proliferation and collagen synthesis of tenocytes between 1 to 20μM and 10 to 20μM respectively. Tensile test on in vivo tissue showed that AgNPs-treated samples had significantly better tensile modulus compared to the untreated ones (p<0.05). SHG imaging suggested a better collagen alignment and density in AgNPs-treated samples. Immunohistochemistry demonstrated that AgNPs suppressed tumor necrosis factor (TNF α) whilst promoted fibromodulin (Fmod) and proliferating cell nucleus antigen (PCNA) expression. Discussion. Collagen is the major component that contributes to the tensile strength of a tendon. Its thickness, abundance and alignment directly affect the strength. In this study, it is found that AgNPs stimulate cell proliferation both in vitro and in vivo which is believed to be the reason of the increase in collagen synthesis. Fmod is an important proteoglycan responsible for collagen fibrillogenesis and TNF α is related to ECM degradation which directly affects collagen integrity. Stimulation of Fmod and alleviation of TNF α therefore promote collagen maturity and integrity which attributes to the improvement in the tensile property of the regenerated tissue. Furthermore, inflammation is known to relate to fibrosis and scarring in healing of many types of tissue. It is therefore postulated that the anti-inflammatory effect of AgNPs is one of the major reasons for this phenomenal healing of tendon. To conclude, this study demonstrates a positive effect of AgNPs to the early events of tendon healing which is important for accelerating the whole healing process and shortening of rehabilitation time

Tendon is a bradytrophic and hypovascular tissue, hence, healing remains a major challenge. The molecular key events involved in successful repair have to be unravelled to develop novel strategies that reduce the risk of unfavourable outcomes such as non-healing, adhesion formation, and scarring. This review will consider the diverse pathophysiological features of tendon-derived cells that lead to failed healing, including misrouted differentiation (e.g. de- or transdifferentiation) and premature cell senescence, as well as the loss of functional progenitors. Many of these features can be attributed to disturbed cell-extracellular matrix (ECM) or unbalanced soluble mediators involving not only resident tendon cells, but also the cross-talk with immigrating immune cell populations. Unrestrained post-traumatic inflammation could hinder successful healing. Pro-angiogenic mediators trigger hypervascularization and lead to persistence of an immature repair tissue, which does not provide sufficient mechano-competence. Tendon repair tissue needs to achieve an ECM composition, structure, strength, and stiffness that resembles the undamaged highly hierarchically ordered tendon ECM. Adequate mechano-sensation and -transduction by tendon cells orchestrate ECM synthesis, stabilization by cross-linking, and remodelling as a prerequisite for the adaptation to the increased mechanical challenges during healing. Lastly, this review will discuss, from the cell biological point of view, possible optimization strategies for augmenting Achilles tendon (AT) healing outcomes, including adapted mechanostimulation and novel approaches by restraining neoangiogenesis, modifying stem cell niche parameters, tissue engineering, the modulation of the inflammatory cells, and the application of stimulatory factors.

Cite this article: Bone Joint Res 2022;11(8):561–574.

Aims

During total knee replacement (TKR), surgeons can choose whether or not to resurface the patella, with advantages and disadvantages of each approach. Recently, the National Institute for Health and Care Excellence (NICE) recommended always resurfacing the patella, rather than never doing so. NICE found insufficient evidence on selective resurfacing (surgeon’s decision based on intraoperative findings and symptoms) to make recommendations. If effective, selective resurfacing could result in optimal individualized patient care. This protocol describes a randomized controlled trial to evaluate the clinical and cost-effectiveness of primary TKR with always patellar resurfacing compared to selective patellar resurfacing.

Aims

Rotator cuff (RC) injuries are characterized by tendon rupture, muscle atrophy, retraction, and fatty infiltration, which increase injury severity and jeopardize adequate tendon repair. Epigenetic drugs, such as histone deacetylase inhibitors (HDACis), possess the capacity to redefine the molecular signature of cells, and they may have the potential to inhibit the transformation of the fibro-adipogenic progenitors (FAPs) within the skeletal muscle into adipocyte-like cells, concurrently enhancing the myogenic potential of the satellite cells.

Obesity decreases patellar tendon stiffness in females but not males Introduction Patellar tendon (PT) injuries are frequent due to excessive mechanical loading during strenuous physical activity. PT injury incidence is higher in females and obese individuals. The reason behind higher tendon injury incidence in females and obese individuals might be structural changes in tendons such as stiffness or elasticity. Tendon stiffness can recently be quantified using shear wave elastography (SWE). We aimed to examine the stiffness of PT in healthy sedentary participants using this new technology. This prospective study was carried out with 58 (34 female, 24 male) healthy sedentary participants between the ages of 18–44 years (27.5±7.7 years). Body mass and body fat percentage were measured with the Bioelectrical Impedance method using Tanita BC-418 MA Segmental Body Composition Analyser (Tanita Corporation, Tokyo, Japan). Participants were subsequently categorized into ‘normal-weight’ (BMI < 23 kg/m2) and ‘obese’ (BMI>27.5 kg/m2). SWE of the PT was measured with the ACUSON S3000 (Siemens Medical Solution, Mountain Wiew, CA, USA) ultrasound device using the Siemens 9L4 (4–9 MHz) linear-array probe with the Virtual Touch Imaging Quantification® method. The measurement was performed by placing the US probe longitudinally on patellar tendon with knee flexed at 30°. The region between about 1 cm distal of patellar bone-tendon junction and 1 cm proximal of bone-tendon junction of tibia was used for PT stiffness measurement (Figure 1). Average of three successive measurements at 10 sec intervals was recorded as PT stiffness. PT stiffness was quantified with MATLAB Version 2015 (Mathworks, Massachusetts, USA) by converting colour data into numbers. PT stiffness, in males, in females, in normal males, in obese males, in normal females, and in obese females was 8.6±1.0 m/sec, 7.4±1.1 m/sec, 8.6±1.1 m/sec, 8.5±1.0 m/sec, 7.9±0.9 m/sec, and 6.2±0.9 m/sec, respectively. Average body fat percentage in males, in females, in normal males, in obese males, in normal females, and in obese females was 20.1±7.4 kg/m2, 30.1±8.1 kg/m2, 15.4±5.2 kg/m2, 24.7±4.6 kg/m2, 25.6±5.5 kg/m2, and 38.1±5.0 kg/m2, respectively. Males PT stiffness was higher when compared to that of females (p=0.000). PT stiffness was similar in obese and normal males (p=0.962) but obese females had lower PT stiffness compared to normal females (p=0.001). PT stiffness of females was lower than males and obesity decreased PT stiffness in females but not in males. The possible explanation of lower PT stiffness in females might be due to their higher estrogen levels that lead to a decrease in estradiol level and collagen synthesis. Lower tendon stiffness in obese females might be metabolic effects due to the increased adipose tissue that contains proteins such as adipokinome, chemerin, lipocalin 2, serum amyloid A3 and adiponectin. These proteins lead to disturbance of tendon homeostasis and decreased collagen content. Altered tendon homeostasis and decreased collagen content may lead to a decrease in tendon stiffness. Decreased PT stiffness in especially in obese women might be associated with increased risk of PT injury

The February 2023 Knee Roundup³⁶⁰ looks at: Machine-learning models: are all complications predictable?; Positive cultures can be safely ignored in revision arthroplasty patients that do not meet the 2018 International Consensus Meeting Criteria; Spinal versus general anaesthesia in contemporary primary total knee arthroplasty; Preoperative pain and early arthritis are associated with poor outcomes in total knee arthroplasty; Risk factors for infection and revision surgery following patellar tendon and quadriceps tendon repairs; Supervised versus unsupervised rehabilitation following total knee arthroplasty; Kinematic alignment has similar outcomes to mechanical alignment: a systematic review and meta-analysis; Lifetime risk of revision after knee arthroplasty influenced by age, sex, and indication; Risk factors for knee osteoarthritis after traumatic knee injury.

Aims

Achilles tendon re-rupture (ATRR) poses a significant risk of postoperative complication, even after a successful initial surgical repair. This study aimed to identify risk factors associated with Achilles tendon re-rupture following operative fixation.

Aims

Knowledge on total knee arthroplasties (TKAs) in patients with a history of poliomyelitis is limited. This study compared implant survivorship and clinical outcomes among affected and unaffected limbs in patients with sequelae of poliomyelitis undergoing TKAs.

Aims

Despite the increasing numbers of ankle arthroplasties, there are limited studies on their survival and comparisons between different implants. The primary aim of this study was to determine the failure rates of primary ankle arthroplasties commonly used in the UK.

Aims

It has been established that mechanical stimulation benefits tendon-bone (T-B) healing, and macrophage phenotype can be regulated by mechanical cues; moreover, the interaction between macrophages and mesenchymal stem cells (MSCs) plays a fundamental role in tissue repair. This study aimed to investigate the role of macrophage-mediated MSC chondrogenesis in load-induced T-B healing in depth.

Aims

Rotator cuff muscle atrophy and fatty infiltration affect the clinical outcomes of rotator cuff tear patients. However, there is no effective treatment for fatty infiltration at this time. High-intensity interval training (HIIT) helps to activate beige adipose tissue. The goal of this study was to test the role of HIIT in improving muscle quality in a rotator cuff tear model via the β3 adrenergic receptor (β3AR).

Tendon injuries are a worldwide problem affecting several age groups and stem cell based therapies hold potential for tendon strategies guiding tendon regeneration. Tendons rely on mechano-sensing mechanisms that regulate homeostasis and influence regeneration. The mechanosensitive receptors available in cell membranes sense the external stimuli and initiate mechanotransduction processes. Activins are members of the TGF-β superfamily which participate in several tendon biological processes. It is envisioned that the activation of the activin receptor, trigger downstream Smad2/3 pathway thus regulating the transcription of tenogenic genes driving stem cell differentiation. In this work, we propose to target the Activin receptor type IIA (ActRIIA) in human adipose stem cells (hASCs), inducing hASCs commitment towards the tenogenic lineage. Since mechanotransduction can be remotely triggered through magnetic actuation combined with magnetic nanoparticles (MNPs), we stimulated hASCs tagged complexes using a vertical oscillating magnetic bioreactor (MICA Biosystems Ltd). Carboxyl functionalised MNPs (Micromod) were coated with anti-ActRIIA antibody (Abcam) by carbodiimide activation. hASCs were then cultured with MNPs-anti-ActRIIA for 14days with or without magnetic exposure (1Hz, 1h/every other day). hASCs cultured alone in αMEM (negative control) or in αMEM supplemented with ActivinA (R&D systems) (positive control of ActRIIA activation) were used as experimental controls. The tenogenic commitment of hASCs was assessed by real time RT-PCR, immunocytochemistry and quantification of collagen and non-collagenous proteins. Moreover, the phosphorylation of Smad2/3 was also evaluated on hASCs incubated for 2, 10, or 30min under magnetic stimulated (1Hz) and non-stimulated conditions. The increased gene expression of tendon related markers and higher ECM proteins deposition suggests that remote magnetic activation of ActRIIA promotes effectively hASCs tenogenic commitment. Furthermore, the detection of phospho-Smad2/3 proteins by ELISA (Cell Signaling Technology) was significantly more intense after 10min in hASCs under magnetic stimulation and in comparison to the control groups. These outcomes suggest that ActRIIA is a mechanosensitive receptor that can be remotely activated upon magnetic stimulation. In conclusion, remotely activation of MNPs tagged hASCs has potential for modulating tenogenic differentiation of stem cells envisioning successful cell therapies for tendon regeneration. Acknowledgements. FCT/MCTES PD/59/2013 (fellowship PD/BD/113802/2015), FCT post-doctoral grant SFRH/BPD/111729/2015, FCT grant IF/00685/2012, and EU-ITN MagneticFun

Aims

Although absorbable sutures for the repair of acute Achilles tendon rupture (ATR) have been attracting attention, the rationale for their use remains insufficient. This study prospectively compared the outcomes of absorbable and nonabsorbable sutures for the repair of acute ATR.

Traditionally open extensor tendon injuries in zones III to V (PIP to MP joints) have been treated with repair and immobilization in extension for 4 to 6 weeks. Early controlled motion protocols have been successfully used in zones VI and VII of the extensors. An early controlled mobilization protocol combined with strong repair for zones III to V extensor tendon lacerations was studied prospectively. From 1999 to 2003, 27 extensor tendon lacerations in 26 patients, mean age 34 years (range 14–70), were treated using dynamic extension splinting. Inclusion criteria were zone III to V, complete lacerations involving the extensor mechanism and possibly the dorsal capsule (without associated fractures or skin deficits) in patients without healing impairment. All injuries were treated in the emergency department with a core Kessler-Tajima suture and continuous epitendon suture. After an initial immobilization in a static splint ranging from 5 days (for zone V) to 3 weeks (for zone III), controlled mobilization was initiated with a dynamic splint that included only the injured finger. The patient was weaned off the dynamic splint 5 weeks after the initial trauma. The patients were treated in an outpatient basis and did not attend any formal physiotherapy program. The mean follow up was 16 months (range 10–24 months). No ruptures or boutoniere deformities were observed and no tenolysis was necessary. The mean TAM was 242deg for the fingers and 119deg for the thumbs. The mean grip and pinch strength averaged 85% and 88% that of the contralateral unaffected extremity. 77% of the patients achieved a good or excellent result in Miller’s classification. The mean loss of flexion was found to be greater than the mean extension deficit. The protocol described above was found to be safe, simple, functional, cost effective and reproducible for zone III to V simple extensor tendon injuries. Success is based on strong initial repair, close physician observation and a cooperative patient. The addition of physiotherapy for patients with flexion deficits in the period immediately after dynamic splinting may ameliorate results

Background. Distal radius fractures are common injuries but no clear consensus regarding optimal management of unstable fractures exists. Open reduction and internal fixation with volar plates is an increasingly popular but the associated complication rate can be 10%. Intramedullary nails are an alternative offering the potential advantages of reduced risk of tendon injury and intra-articular screw penetration. This article systematically reviews the published literature evaluating the biomechanics, outcomes and complications of intramedullary nails in the management of distal radius fractures. Methods. A systematic review of Medline and EMBASE databases was performed for studies reporting the biomechanics, functional outcome or complications following intramedullary nailing of distal radius fractures. Critical appraisal was performed with respect to validated quality assessment scales. Results. 16 studies were included for review. The biomechanical studies concluded that intramedullary nails had at least comparable strength to locking plates. The clinical studies reported that IM nailing was associated with comparable ROM, functional outcome and grip strength to alternative fixation techniques. However, the mean complication rate was 17.6% (range 0 to 50%) with the most common complication being neurapraxia of the superficial radial nerve in 9.5%. Conclusion. This systematic review of pooled data from published series has shown that IM nailing can give comparable clinical results to current treatment modalities in extra-articular and simple intra-articular distal radius fractures. However the evidence is insufficient to determine whether IM nailing has any clinically important advantage over well-established alternatives. The complication rate reported is higher than that in contemporary studies for volar plating and this raises concerns about the role of this technique particularly when comparative studies have failed to show any major advantage to its use. Further adequately powered RCTs comparing the technique to both volar plates and percutaneous wire fixation are required. Level of evidence. IIa – systematic review of cohort studies. Conflict of Interests. The authors confirm that they have no relevant financial disclosures or conflicts of interest. Ethical approval was not sought as this was a systematic review

An established rabbit model was used to preliminarily investigate the effect of acellular triphase, namely bone-cartilage-tendon, scaffold (ATS) sandwiched with autologous bone mesenchymal stem cells (BMSCs) sheets on tendon-bone interface healing. Bone, fibrocartilage and tendon tissue were harvested from the rabbits and sectioned into a book-type scaffold. The scaffolds were decellularized and their characterization was presented. BMSCs were isolated and co-cultured with the scaffolds to verify their cytocompatibility. BMSCs sheets were fabricated and inserted into the book page of the scaffold to construct an autologous BMSCs-sheets/book-type ATS complex. The complex was implated in the right knee of rabbits which operated standard partial patellectomy for TBI regeneration using Imaging, histological and biomechanical examinations. The bone, fibrocartilage and tendon tissue were sectioned into a book-type scaffold before decellularization. Then we decellularized the above tissue and mostly preserved their microstructure and composition of the natural extracellular matrix, including collagen and proteoglycan. After the physicochemical and biological properties of the book-type ATS were evaluated, autologous BMSCs sheets were inserted into the book page of the scaffold to construct an autologous BMSCs-sheets/book-type ATS implants for TBI regeneration. In addition, the ATS has the advantages of non-toxicity, suitable for cell adhesion and growth as well as low immunogenicity while co-cultured with the BMSCs. At the same time, different scaffolds has the ability to induce the osteogenic, chondrogenic and tenogenic differentiation of BMSCs by immunofluorescence, reverse transcription-polymerase chain reaction and western blot analysis. To determine the efficacy of the tissue-engineered implants for TBI regeneration, we transplanted it into a rabbit patella-patellar tendon (PPT) injury model, and the rabbits were sacrificed at postoperative week 8 or 16 for the radiological, histological, and mechanical evaluation. Radiologically, Synchrotron radiation micro-computed tomography (SR-μCT) showed that BMSCs/ATS group significantly increased bone area, BV/TV, trabecular thickness and trabecular number at the healing interface as compared with other groups at postoperative week 8 or 16. Histologically, the BMSCs/ATS group showed more woven bone, and a more robust fibrocartilaginous junction with a characteristic matrix rich in proteoglycans was seen at the PPT healing interface in comparison with other groups after 8 weeks. At week 16, the healing interface in 3 groups displayed better remodeling with respect to postoperative week 8. Healing and remodeling at the PPT junction were almost complete, with a resemblance to a healthy BTI consisting of the characteristic 4 zones in all groups. At last, we used biomechanical test as functional parameters to evaluate the quality of tendon-bone healing. Biomechanical testing indicated that BMSCs/ATS group showed significantly higher failure load and stiffness than other groups at postoperative week 8 and 16. The complex composed of acellular triphase, namely bone-cartilage-tendon, scaffold (ATS) sandwiched with autologous bone mesenchymal stem cells (BMSCs) sheets can simulate the gradient structure of tendon-bone interface, inducing stem cell directional differentiation, so as to promote patella-patellar tendon interface healing effectively after injury

Aims

Avulsion of the proximal hamstring tendon origin can result in significant functional impairment, with surgical re-attachment of the tendons becoming an increasingly recognized treatment. The aim of this study was to assess the outcomes of surgical management of proximal hamstring tendon avulsions, and to compare the results between acute and chronic repairs, as well as between partial and complete injuries.

Hip and groin injuries are common in athletes who take part in high level sports. Adductor muscle tendon injuries represent a small but important number of these injuries. Avulsion of the tendons attached to the symphysis pubis has previously been described: these can be managed both operatively and non-operatively. We describe an uncommon variant of this injury, namely complete avulsion of the adductor sleeve complex: this includes adductor longus, pectineus and rectus abdominis. We go on to describe a surgical technique which promotes a full return to the pre-injury level of sporting activity. Over a period of ten years, 15 high-level athletes with an MRI-confirmed acute adductor complex avulsion injury (six to 34 days old) underwent surgical repair. The operative procedure consisted of anatomical re-attachment of the avulsed tissues in each case and mesh reinforcement of the posterior inguinal wall in seven patients. All underwent a standardised rehabilitation programme, which was then individualised to be sport-specific. One patient developed a superficial wound infection, which was successfully treated with antibiotics. Of the 15 patients, four complained of transient local numbness which resolved in all cases. All patients (including seven elite athletes) returned to their previous level of participation in sport. Cite this article: Bone Joint J 2015;97-B:1488–92

Objectives. There are various pin-in-plaster methods for treating fractures of the distal radius. The purpose of this study is to introduce a modified technique of ‘pin in plaster’. Methods. Fifty-four patients with fractures of the distal radius were followed for one year post-operatively. Patients were excluded if they had type B fractures according to AO classification, multiple injuries or pathological fractures, and were treated more than seven days after injury. Range of movement and functional results were evaluated at three and six months and one and two years post-operatively. Radiographic parameters including radial inclination, tilt, and height, were measured pre- and post-operatively. Results. The average radial tilt was 10.6° of volar flexion and radial height was 10.2 mm at the sixth month post-operatively. Three cases of pin tract infection were recorded, all of which were treated successfully with oral antibiotics. There were no cases of pin loosening. A total of 73 patients underwent surgery, and three cases of radial nerve irritation were recorded at the time of cast removal. All radial nerve palsies resolved at the six-month follow-up. There were no cases of median nerve compression or carpal tunnel syndrome, and no cases of tendon injury. Conclusion. Our modified technique is effective to restore anatomic congruity and maintain reduction in fractures of the distal radius. Cite this article: Bone Joint Res 2015;4:176–180

The incorporation of platelet rich plasma (PRP) in the treatment of various musculoskeletal conditions has increased exponentially over the past decade. While described most often as an augment or treatment for tendinopathies and acute tendon injuries, more recently, PRP has been described as an adjunct to arthroplasty procedures, mostly with respect to knee arthroplasty. In the shoulder, only a single study has been published, in which Zavadil and colleagues performed a randomised study of 40 patients undergoing total shoulder arthroplasty undergoing either treatment with autologous platelet gel and platelet poor plasma (n=20) or undergoing no biologic treatment (control group, n=20). The authors noted that the treatment group had significantly lower pain scores, less pain medication requirements, and improved internal rotation when compared to controls; in addition, there were no significant differences in post-operative (compared to pre-operative) hemoglobin levels or length of stay. The vast majority of arthroplasty studies discussing PRP analyze the impact of treatment on wound healing, post-operative pain, post-operative range of motion, and need for post-operative blood transfusions. Unfortunately, due to the substantial variability of methodology (not all PRP preparations are the same) in the available studies as well as the variability in outcomes reporting, direct comparison between different studies is not feasible. Here, we discuss the basic science elements of PRP relevant to arthroplasty, the variability of PRP solutions, the specific applications of PRP in arthroplasty, and the latest clinical outcomes analyses of patients undergoing PRP therapy in conjunction with shoulder arthroplasty

Tendon injuries are associated with the formation of inferior, disorganized scar tissue at the tendon bone insertion site and high failure rates. Two major processes are discussed being key players: the inflammatory reaction upon tear and the remodeling process of the tendon. In a previous study we demonstrated that the profile of MMPs and TIMPs, being key factors of tendon modeling and remodeling, is altered in tenocytes of rotator cuff tears from donors with higher age (>65 years) and degenerative status (high degree of muscle fatty infiltration)[1]. But do these cells also show different expression of inflammatory cytokines or react different upon cytokine stimulation? The aim of our project was to analyze the expression of inflammatory cytokines in human tenocyte-like cells (hTLCs) on mRNA-level and the responsiveness to cytokine stimulation regarding differences between varying donor characteristics such as age, sex and the degenerative status of the tendon. TLCs were isolated from SSP tendon biopsies from 16 male and 14 female donors undergoing arthroscopic or open shoulder surgery. Cells from each donor (passage 1 or 2) were seeded in a 6-well plate and RNA was isolated after 7 days of culture. Quantitative Real-Time PCR was performed to analyze the expression of IL-6, IL-1β, TNF-α, IL-10, IL-33, TGF-β1 and COX-2. Furthermore, hTLCs of 12 male donors were stimulated for 3 days with a combination of TNF-α and IFN-γ (10ng/ml). The effect of the cytokines was analyzed by flow cytometry regarding surface marker expression: ICAM (CD54), VCAM (CD106), and Major Histocompatibility Complex (MHC)-class I and MHC-class II. Statistics: Mann-Whitney-U-Test, Spearman´s-Rho-correlation, p≤0.05. Gene expression analysis revealed high levels of IL-6, TGF-β1 and COX-2 in hTLCs but low expression of TNF-α and IL-10. No differences in the expression of the inflammatory cytokines were found between low and high fatty infiltration or with respect to age. The stimulation of the hTLCs with TNF-α and IFN-γ increased the number of ICAM and VCAM positive cells up to 100% and 97±5%, respectively. MHC-class II was not expressed on unstimulated cells but 77±17% MHC-class II positive cells were present after stimulation. All unstimulated cells were positive for MHC-class I, but the MFI (Mean Fluorescent Intensity) increased after stimulation. No significant difference in the expression of surface markers was detected when comparing tenocytes of donors with low and high muscle fatty infiltration. In contrast to the significant changes in expression levels of MMPs and TIMPs in tenocytes of donors with different age and degenerative status[1], we could not detect any significant changes in the expression of inflammatory cytokines or in the responsiveness of these tenocytes upon cytokine stimulation. All tenocytes showed the potential to respond to inflammatory processes. This indicates that the response of the tenocytes to inflammatory stimuli seems to be independent of donor characteristics, whereas the tendon remodeling might depend on age and degenerative status of the donor

The majority of studies reporting sensitivity and specificity data for imaging modalities and physical examination tests for long head of biceps (LHB) tendon pathology use arthroscopy as the gold standard. However, there is little published data to validate this as an appropriate benchmark. The aim of this study was to determine the maximum length of the LHB tendon that can be seen at glenohumeral arthroscopy and whether it allows adequate visualisation of common sites of pathology. Seven female cadaveric specimens were studied. Mean age was 74 years (range 44–96 years). Each specimen underwent arthroscopy in lateral decubitus (LD) and beach chair (BC) positions. The LBH-tendon was tagged with a suture placed with a spinal needle marking the intra-articular length and the maximum excursions achieved using a hook and a grasper in both LD and BC positions. T-tests were used to compare data. The mean intra-articular and extra-articular lengths of the tendon were 23.9 mm and 82.3 mm respectively. The mean length of tendon that could be visualised by pulling it into the joint with a hook was significantly less than with a grasper (LD: hook 29.9 mm, grasper 33.9 mm, mean difference 4 mm, p=0.0032. BC: hook 32.7 mm, grasper 37.6 mm, mean difference 4.9 mm, p=0.0001). Using the BC position allowed visualisation of a significantly greater length than the LD position when using either a hook (mean difference 2.86 mm, p=0.0327) or a grasper (mean difference 3.7 mm, p=0.0077). The mean length of the extra-articular part of the tendon visualised using a hook was 6 mm in LD and 8.9 mm in BC. The maximum length of the extra-articular portion visualised using this technique was 14 mm (17%). Pulling the tendon into the joint with a hook does not allow adequate visualisation of common distal sites of pathology in either LD or BC. Although the BC position allows a significantly greater proportion of the tendon to be visualised this represents a numerically small value and is not likely to be clinically significant. The use of a grasper also allowed greater excursion but results in iatrogenic tendon injury which precludes its use. The reported incidence of pathology in Denard zone C (distal to subscapularis) is 80% and in our study it was not possible to evaluate this zone even by using a grasper or maximum manual force to increase excursion. This is consistent with the extremely high rate of missed diagnoses reported in the literature. Surgeons should be aware that the technique of pulling the LHB-tendon into the joint is inadequate for visualising distal pathology and results in a high rate of missed diagnoses. Furthermore, efforts to achieve greater excursion by “optimum” limb positioning intra-operatively do not confer an important clinical advantage and are probably unnecessary

Introduction. Hip and groin injuries are common in athletes participating in high level sports. Adductor muscle tendon injuries represent a small but important number of these injuries. Avulsion injuries involving tendons attaching to the symphysis pubis have previously been described and can be managed both operatively and non-operatively. The aim is to describe a rare variant of this injury; complete avulsion of the adductor sleeve complex including adductor longus, pectineus and rectus abdominus. A surgical technique is then outlined which promotes a full return to pre-injury level of sporting activity. Patients/Materials & Methods. Fifteen high level athletes with an MRI confirmed acute adductor complex avulsion injury (6–34 days) were identified from the institution's sports injury database over a 10 year period. All underwent surgical repair. The operative procedure comprised anatomical attachment of the avulsed tissues in all cases (plus mesh reinforcement of the inguinal wall in 7 patients). All underwent a standard format of rehabilitation which was then individualised to be sport specific. Results. One patient developed a superficial wound infection which was successfully treated with antibiotics. 12 out of 15 patients complained of transient local numbness which resolved in all cases. All patients (including 7 elite athletes) returned to their previous level of participation in sport. Discussion. Injury to the triad of adductor longus, pectineus and rectus abdominus should be considered in athletes presenting with groin pain following forced adduction. All athletes underwent early surgical exploration, previous studies have shown prolonged symptoms in early conservative management. Adductor tenotomy has shown previously acceptable results but may be less suitable in elite athletes with higher functional demands when operative repair has been shown to be successful. Conclusion. Operative repair of acute sleeve avulsion of the adductor complex in high level athletes, followed by sport specific rehabilitation promotes return to previous level of participation in sport

Introduction. The ability of tendons to withstand stress generally decreases with age, often resulting in increased tissue degeneration and decreased regeneration capacity. However, the underlying molecular and cellular mechanisms of tendon senescence remain poorly characterized. Therefore, the aim of the current study was to identify genes showing an age-dependent altered expression profile in tendons. Materials and Methods. A suppression-subtractive-hybridization (SSH) screen comparing cDNA libraries generated from Achilles tendons of mature-adult (3 months) and old (18 months) female C57BL/6 mice was conducted. Subsequently, the differential expression of the identified genes was validated by RT-qPCR and selected genes were then further analysed by immunohistochemistry and Western blot. To investigate age-related structural alterations in the collagenous extracellular matrix we applied SHG-microscopy and TEM. In vitro experiments with young and old tendon derived stem/progenitor cells (TDSCs) involved wounding assays, tendon-like constructs as well as collagen gel contraction assays. Results. Among 168 identified genes, several ECM genes showed a differential expression, including Col1a1, Col3a1, fibronectin, fibromodulin, thrombospondin-1, decorin, biglycan, lysyl oxidase, and Sparc. As evidenced by RT-qPCR the mRNA levels of these genes were down-regulated in old tendons and in old TDSCs. Additionally, protein content of SPARC and Lysyl oxidase was diminished in vitro in cellular extracts from old TDSCs. The impact of Sparc on tendon ageing was further analysed in young and old Sparc−/− C57BL/6 as well as in age-matched wildtype mice. Tendons of Sparc−/− mice are generally thinner and TEM revealed thinner collagen fibrils and a larger interfibrillar area. Further, TDSCs of old and Sparc−/− tendons formed thinner in vitro tendon constructs, showed a higher collagen gel contraction capacity, and display altered cell-ECM adhesion and cell migration properties when compared to young wildtype cells. Employing SHG-microscopy we further observed age-related changes in the collagenous structure of Achilles tendons. Discussion. The decreased expression of ECM proteins and modulators thereof in old tendons in combination with structural changes is potentially associated with an increased risk of tendon injury in the elderly, since structure and composition of the tendon are directly related to its function

Background. Adductor muscle and tendon injuries are commonly seen in sport. Complete adductor avulsions have been described and can be managed non-operatively or operatively. A rare variant of this injury is the complete avulsion of the adductor complex with the pectineus and rectus abdominus amounting to a complete sleeve avulsion from the pubis. This is a severe injury that is increasingly recognised due to improved imaging and lower diagnostic threshold. Purpose. We describe the surgical management of twelve athletes with this severe injury. Study design. Prospective case series - Level of evidence, 4. Methods. All the injuries were prospectively collected onto our institutional pelvic sports injury database. This series summarises the outcome in twelve consecutive cases where surgery was undertaken after presentation with an acute avulsion (6–34 days) in athletes. The procedure comprised anatomical reattachment of the avulsed tissues with mesh reinforcement of the inguinal wall in seven patients. An independent physiotherapist reviewed all patients. Results. One patient developed a superficial wound infection treated with antibiotics. Transient complaints of local numbness were common but all twelve sportsmen returned to high-level sport (five elite) at an average of thirteen weeks (10–21 weeks). Conclusion. Awareness of the possibility of this complex injury is important and there should be a low threshold for investigation. In elite athletes operative intervention is associated with good clinical outcomes and successful return to sport

Repair of tendon injuries aims to restore length, mechanical strength and function. We hypothesise that Demineralised Cortical Bone (DCB) present in biological tendon environment will result in remodelling of the DCB into ligament tissue. A cadaveric study was carried out to optimize the technique. The distal 1cm of the patellar tendon was excised and DCB was used to bridge the defect. 4 models were examined, Model-1: one anchor, Model-2: 2 anchors, Model-3: 2 anchors with double looped off-loading thread, Model-4: 2 anchors with 3 threads off-loading loop. 6 mature sheep undergone surgical resection of the distal 1cm of the right patellar tendon. Repair was done using DCB with 2 anchors. Immediate mobilisation was allowed, animals were sacrificed at 12 weeks. Force plate assessments were done at weeks 3, 6, 9 and 12. Radiographs were taken and pQCT scan was done prior to histological analysis. In the cadaveric study, the median failure force for the 4 models; 250N, 290N, 767N and 934N respectively. In the animal study, none of the specimens showed evidence of ossification of the DCB. One animal failed to show satisfactory progress, X-rays showed patella alta, on specimen retrieval there was no damage to the DCB and sutures and no evidence of anchor pullout. Functional weight bearing was 79% at week12. Histological analysis proved remodelling of the collagen leading to ligamentisation of the DCB. Results prove that DCB can be used as biological tendon substitute, combined with the use of suture bone anchor early mobilisation can be achieved

Aims

Arthroplasty has become increasingly popular to treat end-stage ankle arthritis. Iatrogenic posterior neurovascular and tendinous injury have been described from saw cuts. However, it is hypothesized that posterior ankle structures could be damaged by inserting tibial guide pins too deeply and be a potential cause of residual hindfoot pain.

Two views of tendon healing’s capability have prevailed since the early 1940’s. This presentation will outline the change in perspective regarding the primary tendon repair potential of intrasynovial flexor tendons and the clinical innovations that have been devised to reduce the inflammatory response and to improve the functional and structural characteristics of repair. Specifically, advanced suture, rehabilitation, and salvage techniques for tendon injuries will be discussed

Summary Statement. ASTM therapy is commonly used to treat Achilles tendinopaty. However, there was no report to evaluate the biomechanical effects, especially the dynamic viscoelasticity. We have shown that ASTM treatment was biomechanically useful for chronic Achilles tendinopathy in an animal model. Introduction. Achilles tendinopathy is a common chronic overuse injury. Because Achilles tendon overuse injury takes place in sports and there has been a general increase in the popularity of sports activities, the number and incidence of Achilles tendon overuse injury has increased. Augmented Soft Tissue Mobilization (ASTM) therapy is a modification of traditional soft tissue mobilization and has been used to treat a variety of musculoskeletal disorders. ASTM therapy is thought to promote collagen fiber realignment and hasten tendon repair. It might also change the biomechanical behavior of the injured tendon, especially the dynamic viscoelasticity. The purpose of this study is to evaluate the effect of ASTM therapy in a rabbit model of Achilles tendinopathy by quantifying dynamic biomechanical properties and histologic features. Patients & Methods. The hind limbs of 12 rabbits were used, and 24 Achilles tendons were injected with collagenase to produce tendon injury. One hind limb of each animal was then randomly allocated to receive ASTM therapy, while the other received no treatment and served as a control. ASTM was performed on the Achilles tendon for 3 minutes on postoperative days 21, 24, 28, 31, 35, and 38. The Achilles tendons were harvested 10 days after the last treatment. Specimens were examined with dynamic viscoelasticity and light microscopy. Results. The mean±SD cross-sectional area for the treated and untreated tendons was 12.30±5.47 mm. 2. and 9.57±8.36 mm. 2. , respectively. The difference between the treated and untreated tendons was statistically significant (P<.01). At all dynamic loading frequencies, the storage modulus in the untreated tendons tended to be higher than that in the treated tendons. At 0.1 Hz and 10 Hz, in the untreated tendons was significantly higher than that in the treated tendons (P=.05). The loss modulus was significantly lower in the treated tendons than in the untreated tendons (P<.05). There was no significant difference in tan δ between the treated and untreated tendons. HE stain showed that the untreated tendon fiber was wavy and kinking and displayed a disordered collagen arrangement. In contrast, the tendon fiber was well aligned in the treated tendons. In the immunohistochemically stained specimens, the type III collagen showed higher color intensity in the untreated tendons than in the treated tendons. Discussion/Conclusion. We have shown that ASTM was a biomechanically useful treatment for chronic Achilles tendinopathy. Biomechanical and histologic data showed the treated Achilles tendons had better biomechanical function and histologic outcomes than the untreated tendons

Introduction/Aim. Flexor tendon injuries of the hand are common with an incidence of over 3000 per annum in the UK. These injuries can affect hand function significantly. Early treatment with optimal repair is crucial to prevent disability. This study aimed at investigating the re-rupture rate following primary flexor tendon repair at our institution and to identify potential risk factors for re-rupture. Methods. 100 flexor tendons' injuries that underwent primary repair over a one-year period were reviewed retrospectively. Data was collected on age, gender, occupation, co morbidities, injured fingers, hand dominance, smoking status, zone of injury, time to surgery, surgeon grade, type of repair and suture, and antibiotic use on included patients. Causes of re-rupture were examined. We compared primary tendon repairs that had a re-rupture to those that did not re-rupture. Univariate and multivariate analysis was undertaken to identify the most significant risk factors for re-rupture. Results. 11 out of 100 (11%) repaired tendons went on to re-rupture. A significantly higher proportion of tendons re-rupture was noted when the repair was performed on the dominant hand (p-value = 0.009), in Zone 2 (0.001), and when a surgical delay of more than 72 hours from the time of injury occurred (0.01). Multivariate regression analysis identified repairs in Zone 2 to be the most significant predictor of re-rupture. Causes of re-rupture included infection in 5, rupture during rehabilitation exercises in 5 and fall in 1 patient. Conclusions. A re-rupture rate of 11% was noted in our study. Patients with Zone 2 injuries, repair on dominant hand and those with a surgical delay of more than 3 days were at higher risk of re-rupture. Careful consideration of these factors especially zone 2 injuries is crucial to reduce this rate. Providing a fast-track pathway for managing these patients can reduce time to surgery

Aim. The purpose of this study was to develop and test the utility of a hybrid barbed-suture in the core repair of digital flexor tendon injuries. Despite offering advantages over traditional suture methods, concerns over the cost, strength to failure and biocompatibility of barbed sutures have hindered their development. Moreover the recent designs have been very complex. We have attempted to develop and test a simple barbed suture, to assess it's viability in flexor tendon repair and in particular to establish a baseline for the efficacy and modes of failure barbed sutures, in order to help provide a basis for future research. Method. The barbed suture device was constructed by inserting 3 steel barbs into the weaved construct of a braided polyester suture. The barbed sutures were inserted into 28 porcine lateral extensor tendons yielding a single sided core repair. Tensile testing of the repair was undertaken using a tabletop load frame with the distal end of the tendon fixed in a cryo clamp. Linear load testing to failure was undertaken. Maximum load, repair excursion and repair stiffness were recorded. Results. The barbed suture technique demonstrated a maximum load to failure of 40.4±16.4N. The excursion of the repair at failure point was 31.4±11.6mm. The stiffness of the repair derived from the linear elastic portion of the load displacement curve was 1.0±0.6N/mm. Conclusions. Use of this barbed suture construct offers a fast, easily applied method of flexor tendon repair. The maximum load to failure is comparable to the commonly used non-barbed suture methods. The suture excursion and stiffness findings suggest gap formation at low loads. Failure of the barbed suture seemed to be resisted by the collagen links between longitudinal tendon fibres. Further developments of this very modifiable construct may lead to a viable alternative to the current repair techniques

Introduction. Tendon injuries remain challenging, secondary healing and prolonged immobilisation result in suboptimal outcome. Previous study by our group showed that demineralised bone matrix (DBM) can result in faster healing of a tendon enthesis. The aim of this study is to test different ways augmenting tendon with DBM to enhance tendon repair and regeneration. Methods. DBM strips were prepared from tibias of mature ewes. Patella, patellar tendon and tibias were dissected and the distal 1 cm of the patellar tendon was excised. 4 models were designed;. Model-1, DBM strip was used to bridge the gap between the tendon and the tibial tuberosity. The DBM strip was stitched to the tendon using one bone anchor. Model-2, similar to model 1 with the use of 2 anchors. Model-3, similar to model 2, construct was off loaded by continuous thread looped twice through bony tunnels sited in the patella and in the tibial tuberosity. Model-4, similar to model 3 with 3 threads as off loading loop. All models were tested for pullout force and mode of failure. Results. The median failure force for model-1 (N=5) was 250N while for model-2 (N=5) was 290N. In model-3 and model-4 failure of the off loading loop was used as end point, 6 samples were tested in each model. Median failure force of model-3 was 767N and for model-4 was 934N. There was no statistical significance between model-1 and model-2 (p=0.249), however statistical significance was found between other models (p=< 0.006). Discussion. A study published in 1996 proved that cortical DBM can be used as ACL graft with evidence of ligamentisation. DBM provides a biologic scaffold with potential for use as ligament and tendon replacement. Our study shows that a tendon rupture can be augmented with DBM giving intial appropriate mechanical strength suitable for in-vivo use

Percutaneous A1 pulley release is being increasingly used as an alternative to open surgical release and injection of local steroids for the treatment of the trigger digit. We treated 43 patients, average age 57 years (range12-78). All trigger digits were grade III-IV (Quinnell classification). A mean duration of pre-operative symptoms was 7.3 months (range 2-13 months). A percutaneous release was performed with a 19-gauge hypodermic needle under local anaesthesia in the outpatient setting. All patients were evaluated with respect to clinical resolution of symptoms and general satisfaction. We report a 97% successful release and only one case of incomplete release. A result in terms of abolishing triggering was immediate and patient acceptance was excellent. By two weeks, all the patients had no pain at the operative site. After a mean follow-up of 30.2 months (range12-50), there had been no recurrences. There were no digital nerve injuries, flexor tendon injuries, and infections. The percutaneous release is a safe and effective technique, which provides significant cost savings. The time from onset of symptoms and grading prognostically is significant and affects the treatment outcome. We recommend the percutaneous technique for typical cases of trigger finger with a palpable nodule and reproducible mechanical triggering. This technique can be the treatment of choice for the established trigger finger (grade III and IV) with symptoms of more than few months' duration. The open technique is reserved for complicated cases such as florid tenosynovitis, locked digit, failed percutaneous release or those involving the thumb

Acute peroneal tendon tears present as a relatively sudden onset of lateral ankle or hindfoot pain, frequently in conjunction with a traumatic episode or injury. Underlying or causative factors, including recurrent ankle sprains, hindfoot varus leading to ankle instability, or dislocating peroneal tendons may be associated and can often lead to peroneal tendon tears being overlooked as a cause of persistent lateral ankle or foot pain. Some apparently acute peroneal tendon tears may represent an acute manifestation of an underlying chronic or subclinical abnormality. The spectrum of peroneal tendinopathies includes tenosynovitis, tendinosis, subluxation or dislocation, stenosing tenosynovitis, disorders of the os peroneum, and conditions related to accessory peroneal tendons, as well as acute and chronic tendon tears. These abnormalities of the peroneal tendons may coexist, and one may lead to another, as evidenced by the significant incidence of tears in the presence of dislocating peronei and ankle instability. Suspicion of the possibility of peroneal tendon injury, coupled with careful clinical examination and appropriate investigation, allows the clinician to identify the extent of damage and to implement a successful management plan. Because peroneal tears signify a mechanical abnormality, this management often entails surgical intervention

Introduction. An educated public are becoming increasingly aware of percutaneous needle fasciotomy (PNF) for the treatment of Dupuytren's contracture. We believe that it has an important place in the management of this condition and have set up a dedicated one-stop clinic to perform this procedure. Methods. A prospective study of 61 patients with Dupuytren's, who have undergone PNF have been recruited so far. The study population includes 50 men and 11 women. The average age is 65. The senior author has operated on 81 fingers including 69 MCP joints, 62 PIP joints and 6 DIP joints. We recorded contractures prior to PNF and immediately following the procedure, as well as any complications. At follow up we recorded the Patient global impression of change (PGIC), DASH scores, degree of straightness of the operated finger and whether they would have the procedure again or recommend it. Results. For MCP joints the average pre treatment contracture was 43. o. and immediately post operatively it was 3. o. For PIP joints the average pre treatment contracture was 48. o. and immediately post operatively it was 17. o. For DIP joints the average pre treatment contracture was 41. o. and immediately post operatively it was 20. o. 8 patients had small skin tears and 2 found it too uncomfortable to continue. No nerve or tendon injuries. Mean follow up was 9 months (6–24). At follow up the average PGIC was 6 (very good) and the average DASH score was 30.9 (excellent). Subjectively the vast majority of fingers remained straight. All but 4 patients would have the procedure again and would recommend it to others. Discussion. This specialist clinic offers a very effective, safe procedure and our patients are highly satisfied withthe results. It is also cost effective for our Department

We compared the bulking and tensile strength of the Pennington modified Kessler, Cruciate and the Savage repairs in an ex vivo model. A total of 60 porcine tendons were randomised to three groups, half repaired using a core suture alone and the remainder employing a core and peripheral technique. The tendons were distracted to failure. The force required to produce a 3 mm gap, the ultimate strength, the mode of failure and bulking for each repair were assessed. We found that there was a significant increase in strength without an increase in bulk as the number of strands increased. The Cruciate repair was significantly more likely to fail by suture pullout than the Pennington modified Kessler or Savage repairs. We advise the use of the Savage repair, especially in the thumb, and a Cruciate when a Savage is not possible. The Pennington modified Kessler repair should be reserved for multiple tendon injuries

Lesions of the anterior interosseous nerve in the forearm are rare and often misdiagnosed as tendon injuries. A consecutive series of 13 patients with this condition referred for electrodiagnosis is reviewed. Only three had originally a correct clinical diagnosis and three were initially considered to have tendon ruptures. Five cases were of mechanical origin and seven due to ‘neuritis’. All showed electrophysiological abnormalities, most commonly involving the pronator quadratus. Late spontaneous recovery was common, and only one case had surgical exploration

Summary Statement. A resorbable and biocompatible polymer-based scaffold was used for the proliferation and delivery of adipose derived stromal cells, as well as delivery of a cell growth/differentiation promoting factor for improved tendon defect regeneration. Introduction. Surgeons perform thousands of direct tendon repairs annually. Repaired tendons fail to return to normal function following injury, and thus require continued efforts to improve patient outcomes. The ability to produce regenerate tendon tissue with properties equal to pre-injured tendon could lead to improved treatment outcomes. The aim of this study was to investigate in vivo tendon regeneration using a biodegradable polymer for the delivery of adipose derived stromal cells (ADSCs) and a polypeptide, growth/differentiation factor-5/(GDF-5), in a tendon gap model. Patients & Methods. Female Fischer 344 rats underwent unilateral Achilles tenotomies. Defects were left un-repaired (Group 1-control), bridged using electrospun 65:35 polylactide-co-glycolide (PLAGA) tubular scaffolds (Group 2), PLAGA/ADSCs (Group 3), or PLAGA/GDF-5 (Group 4) scaffold composites. The plantaris was left intact. Operative limbs were immobilised for 10–14 days, followed by unrestricted activity. The rats were sacrificed at 4 weeks or 8 weeks after surgery, and tendons were assessed with histological, biochemical, and mechanical analyses. Results. PLAGA, PLAGA/ADSCs, and PLAGA/GDF-5 groups showed increased collagen I gene expression at both the 4 and 8 week time points (p<0.05). Tenomodulin (Tnmd) is the mature tendon phenotype marker unique to tendon tissue. Both the PLAGA/ADSCs and PLAGA/GDF-5 groups demonstrated increased tenomodulin expression at 4 and 8 weeks (p<0.05). Ultimate tensile load strength was improved in all PLAGA groups (2, 3, and 4) versus the control. Both composite groups (2 and 3) showed improved collagen deposition, as indicated by increased Collagen Area Fraction (CAF), approaching that of normal tendon at 8 weeks (p<0.05). Scaffold resorption was evident at 4 weeks, with complete replacement of the polymer with regenerate tissue and minimal gap formation at 8 weeks without evidence of an adverse inflammatory reaction. Defects bridged using the scaffold seeded with ADSCs showed improved collagen organization and increased modulus of elasticity compared with controls as well as properties approaching those of native tendon. Discussion/Conclusions. These results demonstrate that a tubular bioresorbable scaffold can promote extracellular matrix synthesis and organization, and the formation of neo-tendinous tissue; as well as serve as a carrier of adipose stromal cells and growth factors that are effective for tendon regeneration. Cells, growth factors and synthetic biomaterial polymers may be combined as a paradigm for regenerative engineering thereby serving as promising options for improved treatments of tendon injuries and potentially improving patient outcomes