No animal model currently exists for hip abductor tendon tears. We aimed to 1. Develop a large animal model of delayed abductor tendon repair and 2. To compare the results of acute and delayed tendon repair using this model. Fourteen adult Romney ewes underwent detachment of gluteus medius tendon using diathermy. The detached tendons were protected using silicone tubing. Relook was performed at six and 16 weeks following detachment, histological analysis of the muscle and tendon were performed. We then attempted repair of the tendon in six animals in the six weeks group and compared the results to four acute repairs (tendon detachment and repair performed at the same time). At 12 weeks, all animals were culled and the tendon–bone block taken for histological and mechanical analysis. Histology grading using the modified Movin score confirmed similar tendon degenerative changes at both six and 16 weeks following detachment. Biomechanical testing demonstrated inferior mechanical properties in both the 6 and 16 weeks groups compared to healthy controls. At 12 weeks post repair, the acute repair group had a lower Movin's score (6.9 vs 9.4, p=0.064), and better muscle coverage (79.4% of normal vs 59.8%). On mechanical testing, the acute group had a significantly improved Young's Modulus compared to the delayed repair model (57.5MPa vs 39.4MPa, p=0.032). A six week delay between detachment and repair is sufficient to produce significant degenerative changes in the gluteus medius tendon. There are significant histological and mechanical differences in the acute and delayed repair groups at 12 weeks post op, suggesting that a delayed repair model should be used to study the clinical problem

The aim of this study was to observe cellular and vascular changes in different stages of full thickness rotator cuff tear.

Biopsies of the Supraspinatus tendon in 40 patients with chronic rotator cuff tears undergoing surgery were analysed using histological and contempary immunocytochemical techniques. Sections were stained with primary antibodies against PCNA (Proliferating cell nuclear antigen), CD34 (QBEnd 10), CD45 (Leucocyte Common Antigen), CD68, D2-40 (Lymphatic Endothelial Marker) and Mast Cell Tryptase. A histological analysis was performed with Mayer’s Haemotoxylin and Eosin, Congo Red and Toluidine Blue.

The reparative response and inflammatory component (figure 1) of the tissue was seen to diminish as the rotator cuff tear size increased. This was evidenced by increasing degeneration and oedema, reducing fibroblast proliferation, reduced thickening of the synovial membrane and reducing vascularity. Macrophage, other leucocyte and mast cell numbers also reduced as tear size increased. Large and massive tears revealed a higher degree of chondroid metaplasia and amyloid deposition when compared to smaller sized tears. There was no association with the patient’s age or duration of symptoms.

Small sized rotator cuff tears retain the greatest potential to heal and have a significant inflammatory component. Tissue from large and massive tears is of such a degenerate nature that it may never heal and this is probably a significant cause of re-rupture after surgical repair in this group. Selection of patients for reconstructive surgery should take into account the composition and healing potential of tendon tissue and its relationship to tear size in chronic tears of the rotator cuff.

Introduction

Following tear of its tendon, the muscle undergoes retraction, atrophy and fatty infiltration. These changes are inevitable and considered irreversible and limit the potential of successful repair of musculotendinous units. It was the purpose of this study to test the hypothesis that administration of anabolic steroids can prevent these muscular changes following experimental supraspinatus tendon release in the rabbit.

We assessed the clinical results, radiographic outcomes and complications of patients undergoing total shoulder replacement (TSR) for osteoarthritis with concurrent repair of a full-thickness rotator cuff tear. Between 1996 and 2010, 45 of 932 patients (4.8%) undergoing TSR for osteoarthritis underwent rotator cuff repair. The final study group comprised 33 patients with a mean follow-up of 4.7 years (3 months to 13 years). Tears were classified into small (10), medium (14), large (9) or massive (0). On a scale of 1 to 5, pain decreased from a mean of 4.7 to 1.7 (p = < 0.0001), the mean forward elevation improved from 99° to 139° (p = < 0.0001), and the mean external rotation improved from 20° (0° to 75°) to 49° (20° to 80°) (p = < 0.0001). The improvement in elevation was greater in those with a small tear (p = 0.03). Radiographic evidence of instability developed in six patients with medium or large tears, indicating lack of rotator cuff healing. In all, six glenoid components, including one with instability, were radiologically at risk of loosening. Complications were noted in five patients, all with medium or large tears; four of these had symptomatic instability and one sustained a late peri-prosthetic fracture. Four patients (12%) required further surgery, three with instability and one with a peri-prosthetic humeral fracture.

Consideration should be given to performing rotator cuff repair for stable shoulders during anatomical TSR, but reverse replacement should be considered for older, less active patients with larger tears.

Cite this article: Bone Joint J 2014;96-B:224–8.

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). Methods. Three-month-old C57BL/6 J mice underwent a unilateral rotator cuff injury procedure. Mice were forced to run on a treadmill with the HIIT programme during the first to sixth weeks or seventh to 12th weeks after tendon tear surgery. To study the role of β3AR, SR59230A, a selective β3AR antagonist, was administered to mice ten minutes before each exercise through intraperitoneal injection. Supraspinatus muscle, interscapular brown fat, and inguinal subcutaneous white fat were harvested at the end of the 12th week after tendon tear and analyzed biomechanically, histologically, and biochemically. Results. Histological analysis of supraspinatus muscle showed that HIIT improved muscle atrophy, fatty infiltration, and contractile force compared to the no exercise group. In the HIIT groups, supraspinatus muscle, interscapular brown fat, and inguinal subcutaneous white fat showed increased expression of tyrosine hydroxylase and uncoupling protein 1, and upregulated the β3AR thermogenesis pathway. However, the effect of HIIT was not present in mice injected with SR59230A, suggesting that HIIT affected muscles via β3AR. Conclusion. HIIT improved supraspinatus muscle quality and function after rotator cuff tears by activating systemic sympathetic nerve fibre near adipocytes and β3AR. Cite this article: Bone Joint Res 2023;12(8):455–466

Aims. Favourable short-term outcomes have been reported following latissimus dorsi tendon transfer for patients with an irreparable subscapularis (SSC) tendon tear. The aim of this study was to investigate the long-term outcomes of this transfer in these patients. Methods. This was a retrospective study involving 30 patients with an irreparable SSC tear and those with a SSC tear combined with a reparable supraspinatus tear, who underwent a latissimus dorsi tendon transfer. Clinical scores and active range of motion (aROM), SSC-specific physical examination and the rate of return to work were assessed. Radiological assessment included recording the acromiohumeral distance (AHD), the Hamada grade of cuff tear arthropathy and the integrity of the transferred tendon. Statistical analysis compared preoperative, short-term (two years), and final follow-up at a mean of 8.7 years (7 to 10). Results. There were significant improvements in clinical scores, in the range and strength of internal rotation and aROM compared with the preoperative values in the 26 patients (87%) who were available for long-term follow-up. These improvements were maintained between short- and long-term follow-ups. Although there was a decreased mean AHD of 7.3 mm (SD 1.5) and an increased mean Hamada grade of 1.7 (SD 0.5) at final follow-up, the rate of progression of cuff tear arthropathy remained low-grade. Comparison between the isolated SSC and combined SSC and reparable supraspinatus tear groups showed no significant differences. At final follow-up, one patient (3.8%) had undergone revision surgery to a reverse shoulder arthroplasty (RSA). No neurological complications were associated with the procedure. Conclusion. Latissimus dorsi transfer for an irreparable SSC tendon tear resulted in a significant clinical improvement, particularly in pain, range and strength of internal rotation and aROM, which were maintained over a mean of 8.7 years following surgery. Given that this was a long-term outcome study, there was a low-grade progression in the rate of cuff tear arthropathy. Thus, the long-term clinical efficacy of latissimus dorsi tendon transfer in patients with irreparable SSC was confirmed as a joint-preserving procedure for these patients, suggesting it as an effective alternative to RSA in young, active patients without degenerative changes of the glenohumeral joint. Cite this article: Bone Joint J 2024;106-B(9):957–963

Partial thickness abductor tendon tears are a significant source of recalcitrant laterally based hip pain. For those that fail conservative treatment, the results of endoscopic repair are highly successful with minimal morbidity. The principal burden is the protracted rehabilitation that is necessary as part of the recovery process. There is a wide gap between failed conservative treatment and successful surgical repair. It is hypothesized that a non-repair surgical strategy, such as a bioinducitve patch, could significantly reduce the burden associated recovery from a formal repair. Thus, the purpose of this study is to report the preliminary results of this treatment strategy. Symptomatic partial thickness abductor tendon tears are treated conservatively, including activity modification, supervised physical therapy and ultrasound guided corticosteroid injections. Beginning in January 2022, patients undergoing hip arthroscopy for intraarticular pathology who also had persistently symptomatic partial thickness abductor tendon tears, were treated with adjunct placement of a bioinducitve (Regeneten) patch over the tendon lesion from the peritrochanteric space. The postop rehab protocol is dictated by the intraarticular procedure performed. All patients are prospectively assessed with a modified Harris Hip Score (mHHS) and iHOT and the tendon healing response examined by ultrasound. Early outcomes will be presented on nine consecutive cases. Conclusions - Will be summarized based on the preliminary outcomes to be reported

Rotator cuff pathology is the main cause of shoulder pain and dysfunction in older adults. When a rotator cuff tear involves the subscapularis tendon, the symptoms are usually more severe and the prognosis after surgery must be guarded. Isolated subscapularis tears represent 18% of all rotator cuff tears and arthroscopic repair is a good alternative primary treatment. However, when the tendon is deemed irreparable, tendon transfers are the only option for younger or high-functioning patients. The aim of this review is to describe the indications, biomechanical principles, and outcomes which have been reported for tendon transfers, which are available for the treatment of irreparable subscapularis tears. The best tendon to be transferred remains controversial. Pectoralis major transfer was described more than 30 years ago to treat patients with failed surgery for instability of the shoulder. It has subsequently been used extensively to manage irreparable subscapularis tendon tears in many clinical settings. Although pectoralis major reproduces the position and orientation of the subscapularis in the coronal plane, its position in the axial plane – anterior to the rib cage – is clearly different and does not allow it to function as an ideal transfer. Consistent relief of pain and moderate recovery of strength and function have been reported following the use of this transfer. In an attempt to improve on these results, latissimus dorsi tendon transfer was proposed as an alternative and the technique has evolved from an open to an arthroscopic procedure. Satisfactory relief of pain and improvements in functional shoulder scores have recently been reported following its use. Both pectoralis minor and upper trapezius transfers have also been used in these patients, but the outcomes that have been reported do not support their widespread use. Cite this article: Bone Joint J 2024;106-B(9):970–977

Background. Weightbearing computed tomography scans allow for better understanding of foot alignment in patients with Progressive Collapsing Foot Deformity. However, soft tissue integrity cannot be assessed via WBCT. As performing both WBCT and magnetic resonance imaging is not cost effective, we aimed to assess whether there is an association between specific WBCT and MRI findings. Methods. A cohort of 24 patients of various stages of PCFD (mean age 51±18 years) underwent WBCT scans and MRI. In addition to signs of sinus tarsi impingement, four three-dimensional measurements (talo-calcaneal overlap, talo-navicular coverage, Meary's angle axial/lateral) were obtained using a post processing software (DISIOR 2.1, Finland) on the WBCT datasets. Sinus tarsi obliteration, spring ligament complex and tibiospring ligament integrity, as well as tibialis posterior tendon degeneration were evaluated with MRI. Statistical analysis was performed for significant (P<0.05) correlation between findings. Results. None of the assessed 3D measurements correlated with spring ligament complex or tibiospring ligament tears. Age, body mass index, and TCO were associated with tibialis posterior tendon tears. 75% of patients with sinus tarsi impingement on WBCT also showed signs of sinus tarsi obliteration on MRI. Of the assessed parameters, only age and BMI were associated with sinus tarsi obliteration diagnosed on MRI, while the assessed WBCT based 3D measurements were, with the exception of MA axial, associated with sinus tarsi impingement. Conclusion. While WBCT reflects foot alignment and indicates signs of osseous impingement in PCFD patients, the association between WBCT based 3D measurements and ligament or tendon tears in MRI is limited. Partial or complete tears of the tibialis posterior tendon were only detectable in comparably older and overweight PCFD patients with an increased TCO. WBCT does not replace MRI in diagnostic value. Both imaging options add important information and may impact decision-making in the treatment of PCFD patients

Tendoscopy in the treatment of peroneal tendon disorders is becoming an increasingly safe, reliable, and reproducible technique. Peroneal tendoscopy can be used as both an isolated procedure and as an adjacent procedure with other surgical techniques. The aim of our study was to review all peroneal tendoscopy that was undertaken at the AOC, by the senior authors (IGW, SH), and to determine the safety and efficacy of this surgical technique. Methods. From 2000 to 2017 a manual and electronic database search was undertaken of all procedures by the senior authors. Peroneal tendoscopy cases were identified and then prospectively analysed. Results. 51 patients (23 male, 28 female) were identified from 2004–2017 using a manual and electronic database search. The mean age at time of surgery was 41.5 years (range 16–83) with a mean follow-up time post operatively of 11.8 months (range 9–64 months). The main indications for surgery were lateral and/or postero-lateral ankle pain and lateral ankle swelling. The majority of cases showed unstable peroneal tendon tears that were debrided safely using tendoscopy. Of the 51 patients, 23 required an adjacent foot and ankle operation at the same time, 5 open and 17 arthroscopic (12 ankle, 5 subtalar). Open procedures included 2 first ray osteotomies, 2 open debridements of accessory tissue, one PL to PB transfer. One patient also had an endoscopic FHL transfer. Complication rates to date have been low: 2 superficial wound infections (4%) and one repeat tendoscopy for ongoing pain. A small proportion of patients with ongoing pain were treated with USS guided steroid injections with good results. Conclusion. Our series of peroneal tendoscopy has a low complication rate with high patient satisfaction at discharge. Results of tendoscopic treatment are similar to open techniques, however its advantages make tendoscopic procedures an excellent method to treat peroneal tendon disorders

Autologous tendon cell injection (ATI) is a promising non-surgical treatment for tendinopathies and tendon tear that address its underlying pathology. The procedure involves harvesting autologous tendon tissue, the isolation of the tendon cells, expansion under quality assured GMP cell laboratory and the injection of the tendon cells via U/S into the degenerative tendon tissue. In clinical practice, the patella (PT) and palmaris longus (PL) tendons are common sites used for tendon tissue biopsy. The objective of this study is to compare the tendon cell quality, identity, purity, doubling time and yield of cells between PT and PL tendons for ATI. Tendon tissue biopsies were harvested from PT via U/S using a 14-gauge needle or resected surgically from the PL tendon. The biopsies were transported to a GMP cell laboratory, where tendon cells were isolated, cultured and expanded for 4 to 6 weeks, and analysed for viability, cell doubling time, cellular characteristics including cell purity, potency and identity (PPI). Tendon samples from 149 patients were analysed (63 PT). Average biopsy weight was 62mg for PT and 119mg for PI (p<0.001). Average cell doubling time (83.9 vs 82.7 hours), cellular yield (16.2 vs 15.2x106), viability (98.7 vs 99.0%) and passage number (3 vs 3) were not significantly different between tendons. Additionally, ddPCR analyses showed no differences of PPI including tendon cell markers of collagen type I, scleraxis and tenomodulin. No post-biopsy complications or contamination were reported for either group. Assessing tendon tissue from palmaris tendon is relatively easier. Tendon tissue biopsy tissue for autologous tendon cell therapy can be obtained from either the PT or PL tendons. Tendon cells isolated from PT and PL were equal in growth characteristics and PPI. There are no differences in the quality of tendon cells isolated from the PT or PL

Purpose. Full-thickness tendon tears of the supraspinatus (SP) are common and can have a significant impact on shoulder function. To optimally treat supraspinatus tendon tears an accurate understanding of its musculotendinous architecture is needed. We have previously shown that the architecture of supraspinatus is complex. It has architecturally distinct regions: anterior and posterior, each of which is further subdivided into superficial, middle and deep parts (Kim et al., 2007). Data of FBL and PA of the torn supraspinatus could enhance clinical decision making and guide rehabilitative treatments (Ward et al., 2006). Currently, however, in vivo US quantification of the fiber bundle architecture of the distinct regions of supraspinatus in subjects with full-thickness tendon tears has not been investigated. PURPOSE: To quantify architectural parameters within the distinct regions of supraspinatus in subjects with a full-thickness tendon tear using the US protocol that we previously developed (Kim et al., 2010), and to compare findings with age and gender matched normal controls. Method. Twelve SP from eight subjects, mean age 576.0 years, were scanned using an US scanner (12 MHz). The SP was scanned in relaxed and contracted states. For the contracted state, SP was scanned with the shoulder in neutral rotation and 60 of active abduction. Fiber bundles of the anterior region (middle and deep) and posterior region (deep) could be visualized and measured. Muscle thickness, FBL, and PA were computed from US scans. Data was analyzed using Mann-Whitney and Wilcoxon Signed Rank Tests (P<0.05). Results. Intra-and inter-rater measurements of FBL were strongly correlated with no significant difference between measurements (P<0.001). In the anterior region, mean FBL did not significantly differ between the pathologic subjects and normal controls. In the pathologic subjects, mean PA was smaller compared to normal controls. The difference was significant between the subjects with a tear and retraction and normal controls (P<0.05). For the posterior region, mean FBL was shorter in the pathologic subjects compared to normal controls. The difference was significant between the subjects with a tear and retraction and normal controls (P<0.05). Conclusion. Findings suggest that significant FBL and PA changes are found with full-thickness tendon tears of SP and different regions of the muscle are impacted differently. Pennation angles are largely impacted in the anterior region and FBL in the posterior. The presence of tendon retraction was found to be related to the amount of change in architectural parameters. Data from this study may be useful to model muscle-joint behavior of the pathologic shoulder. This US protocol may be beneficial to carry out a larger study to determine which comes first, architectural changes in the muscle, or tendon tearing. If we identify changes in muscle architecture predate tendon pathology, we could develop techniques to prevent tendon tearing

The rotator cuff tendinopathy is one of the most common shoulder problems leading to full-thickness rotator cuff tendon tear and, eventually, to degenerative arthritis. Recent research on rotator cuff tendon degeneration has focused on its relationship to cell death. The types of cell death known to be associated with rotator cuff tendon degeneration are apoptosis, necrosis, and autophagic cell death. The increased incidence of cell death in degenerative tendon tissue may affect the rates of collagen synthesis and repair, possibly weakening tendon tissue and increasing the risk of tendon rupture. The biomolecular mechanisms of the degenerative changes leading to apoptotic cell death in rotator cuff tenofibroblasts have been identified as oxidative-stress-related cascade mechanisms. Furthermore, apoptosis, necrosis, and autophagic cell death are all known to be mediated by oxidative stress, a condition in which ROS (reactive oxygen species) are overproduced. Lower levels of oxidative stress trigger apoptosis; higher levels mediate necrosis. Although the signaltransduction pathway leading to autophagy has not yet been fully established, ROS are known to be essential to autophagy. A neuronal theory regarding rotator cuff degeneration has been developed from the findings that glutamate, a neural transmitter, is present in increased concentrations in tendon tissues with tendinopathy and that it induces rat supraspinatus tendon cell death. Recent studies have reported that hypoxia involved in rotator cuff tendon degeneration. Because antioxidants are known to scavenge for intracellular ROS, some studies have been conducted to determine whether antioxidants can reduce cell death in rotator cuff tendon-origin fibroblasts. The first study reported that an antioxidant has the ability to reduce apoptosis in oxidative-stressed rotator cuff tenofibroblasts. The second study reported that antioxidants have both antiapoptotic effects and antinecrotic effects on rotator cuff tendon-origin fibroblasts exposed to an oxidative stimulus. The third study reported that an antioxidant has antiautophagic-cell-death effects on rotator cuff tendon-origin fibroblasts exposed to an oxidative stimulus. The fourth study reported that glutamate markedly increases cell death in rotator cuff tendonorigin fibroblasts. The glutamate-induced cytotoxic effects were reduced by an antioxidant, demonstrating its cytoprotective effects against glutamate-induced tenofibroblast cell death. The fifth study reported that hypoxia significantly increases intracellular ROS and apoptosis. The hypoxia-induced cytotoxic effects were markedly attenuated by antioxidants, demonstrating their cytoprotective effects against hypoxia-induced tenofibroblast cell death. In conclusion, antioxidants have cytoprotective effects on tenofibroblasts exposed in vitro to an oxidative stressor, a neurotransmitter, or hypoxia. These cytoprotective effects result from antiapoptotic, antinecrotic, and antiautophagic actions involving the inhibition of ROS formation. These findings suggest that antioxidants may have therapeutic potential for rotator cuff tendinopathy. Further studies must be conducted in order to apply these in vitro findings to clinical situations

Introduction. Patients with hip abductor tendon tears amenable to endoscopic repair tend to be severely disabled and older. However, low preop baseline patient reported outcome (PRO) and advancing age are each often reported to be a harbinger of poor result with hip arthroscopy. Thus, the purpose of this study is to report the demographic makeup of this population and how these patients faired in terms of preop scores and reaching both Minimal Clinically Important Difference (MCID) and Substantial Clinical Benefit (SCB). Methods. Sixty-six consecutive hips in 64 patients (2 bilateral) undergoing endoscopic abductor tendon repair with a hollow core bioabsorbable suture anchor and having achieved two-year follow-up were prospectively assessed with modified Harris Hip Score (mHHS) and international Hip Outcome Tool (iHOT) scores. The MCID for patients undergoing hip arthroscopy has previously been determined as 8 for the mHHS and 13 for the iHOT. SCB has been determined as 20 for the mHHS and 28 for the iHOT. Subgroups were compared using the independent samples t-test. Results. The average age was 57 years (range 22–83 years) with 59 females and 5 males. Post-operative follow-up averaged 28 months (range 24–60). There were 33 full-thickness and 33 partial-thickness tears; 39 gluteus medius tears, 25 medius and minimus tears, and 2 isolated minimus tears. Among the 66 hips, the average preop mHHS was 48.8 with 98.5% achieving MCID and 93.8% SCB. Among 60 hips that had complete iHOT data, the average preop score was 30.0 with 98.3% achieving MCID and 88.3% SCB. There were no complications. One patient underwent repeat arthroscopy for joint debridement at 12 months following abductor repair, and one subsequently underwent total hip replacement at 11 months following repair. There was no statistically significant difference between subgroups of full thickness/partial thickness tears, or single/two tendon tears. Conclusion. This report of endoscopic abductor tendon repair represents a heterogeneous group of single and two tendon involvement with partial and full thickness tears. Collectively these patients can respond exceptionally well in terms of MCID (98.5% mHHS; 98.3% iHOT) and SCB (93.8% mHHS; 88.3% iHOT), even in the presence of low preop baseline scores (average 48.8 mHHS; 30 iHOT) and older age (average 57 years). For any tables or figures, please contact the authors directly

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

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

INTRODUCTION. There is increasing evidence for a multi-stage model of rotator cuff (RC) tendon tears, wherein healing is affected by tear size. The underlying pathophysiology however is not fully understood. Changes in the production and remodeling of the RC extracellular matrix (ECM) are likely to be important determinants of RC tendinopathy as they affect healing and the ability to bear loads. This study aimed to gain greater insight into size related tear pathogenesis by analyzing gene expression profiles from normal, small and massive RC tears. METHODS. The genetic profiles of 28 human RC tendons were analyzed using microarrays representing the entire genome. 11 massive and 5 small torn RC tendon specimens were obtained from tear edges intraoperatively, and compared to 12 age matched normal controls. Semiquantitative real-time polymerase chain reaction (RT-PCR) and immunohistochemistry were performed for validation. RESULTS. Numerous insightful gene changes were detected. Key changes included upregulation of aggrecan in massive tendon tears compared to normal controls, but not in small tears (p < 0.05 and > 2-fold change). Matrix metallopeptidases (MMP)-3,-10,-12,-13,-15,-21,-25 and a disintegrin and metallopeptidase (ADAMs)-12,-15,-22 were significantly upregulated in tears. Aggrecan was upregulated in massive tendon tears but not in small tears. Amyloid was downregulated in the small and massive tear groups when compared to normals. BMP-5 was upregulated in small tears only when compared to normals. As part of the chemotaxis pathway, IL-3,-10,-13,-15,-18 were upregulated in tears, whereas downregulation of IL-1,-8,-11,-27, was seen. RT-PCR and immunohistochemistry confirmed altered gene expression. CONCLUSION. The gene profiles of normal, small and massive RC tear groups suggested they are biologically distinct groups. In addition to confirming altered gene expression in pathways reported in previous studies, this study has identified a number of novel pathways which are affected between the different tendon tear and normal groups. This study identified that RC tear pathogenesis is contributed to by ECM remodeling genes, chemotaxis genes, aggrecan and amyloid. Further investigation is required to determine whether some of these genes may potentially have a role as biomarkers of failure. Modulating these ECM pathways may be a useful treatment strategy for improving clinical outcomes

The practice of rotator cuff repair rapidly moves towards arthroscopic techniques especially for single tendon tears. Although the clinical results are relatively well established, the structural results of open rotator cuff repair and their correlation with the clinical outcome are poorly known. In order to provide a baseline for future studies using other repair techniques, this study was carried out to assess the structural changes in the repaired musculotendinous unit and to correlate these findings with the clinical outcome after rupture and repair of an isolated full thickness single tendon tear of the rotator cuff. To prospectively assess the quality of an open rotator cuff tendon repair technique, to determine how structural changes of rotator cuff muscles are affected by tendon repair, and to correlate the structural results of MRI studies with the clinical outcome. Direct open repair of a complete, isolated single tendon tear of the rotator cuff resulted in significant improvement in function and objective evidence of tendon healing on MRI. Successful direct repair was not associated with recovery of preoperative muscular atrophy or fatty infiltration when comparing Goutallier stage fatty infiltration between pre and postoperative patients. The age and gender-adjusted Constant score increased significantly from an average of 63.9% preoperatively to 94.5% postoperatively (p< 0.0001). Pain improved significantly from 6.8 points to 13.2 points on a visual analogue scale. (p< 0.0001). Activities of daily living increased from 11.2 points preoperatively to 17.9 points postoperatively (p< 0.0001). Anterior elevation, abduction and internal rotation improved significantly for subscapularis and supraspinatus repairs, but there was no significant change in external rotation. The overall rerupture rate was 12.5%. There was no significant improvement or recovery of muscular atrophy or fatty infiltration after tendon repair. Thirty-two consecutive open repairs of a single tendon tear of the rotator cuff were analysed. The supraspinatus tendon was involved in twenty-two patients and the subscapularis tendon in ten patients. All tendons were repaired using an open technique, a modified Mason-Allen suturing technique, and transosseus fixation with non-absorbable suture material knotted over a bone augmentation device

Introduction. Hip abductor tendon tears have been referred to as “rotator cuff tears of the hip,” and are a recognized etiology for persistent, often progressive, lateral hip pain, weakness, and limp. Multiple repair techniques and salvage procedures for abductor tendon tears have been reported in the literature; however, re-tear remains a frequent complication following surgical repair. This study compares the short-term outcomes of open abductor tendon repairs with decortication and suture fixation (DSF) compared to a modified technique repair into a bone trough (BT), to determine best surgical results for large abductor tendon avulsions. Additionally, surgical treatment of small tears versus large tears was examined. Methods. The outcomes of 37 consecutive hip abductor tendon repairs treated between January 2009 and December 2017 were retrospectively reviewed. Large tears were defined as detachment of 33–100% of the gluteus medius insertion. There were 15 DSF and 10 BT cases. Postoperative pain, ability to perform single leg stance, hip abduction, and Trendelenburg lurch, were examined. Small tears (12 cases) were defined as having no gluteus medius avulsion from the trochanteric insertion and were comprised of longitudinal tears (repaired side-by-side) and isolated gluteus minimus tears (repaired by tenodesis to the overlying gluteus medius). Standard statistical analyses were utilized. Type I error for all analyses was set at α=0.05. Results. When comparing large tear repair outcomes, repairs into a BT had superior outcomes to repairs with DSF: 0 (BT) versus 6 (DSF, 40%) failure rate (p<0.05), and greater reductions in pain at one-year post surgery (Δ VAS: BT, −5.70±0.97 | DSF: −2.73±0.69; p<0.01), ability to perform a single leg stance and hip abduction (90% and 100% vs 47% and 73%) (p<0.05). Clinical strength ratings were higher for repairs into a BT, but this did not reach statistical significance. When comparing large to small tear repair outcomes, small tears were found to have lower VAS pain scores and higher clinical strength ratings during both the pre-op and 1-year post-op time points (p<0.05). A higher percentage of those with small tears were able to perform a single leg stance and hip abduction (100%) compared to those with large tears (64% and 78% respectively) (p<0.05). A significantly higher frequency of residual lurch was also observed for those with large tears; 56% compared to small tears at 0%. Conclusions. Utilizing a BT repair significantly improved surgical results for large abductor tendon avulsions. Level of evidence: Therapeutic level IV case series

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