Age and Sex Comparison of the Canine Supraspinatus Tendon Using Quantitative Magnetic Resonance Imaging T2 Mapping.

OBJECTIVE: The normal canine supraspinatus tendon has properties commonly attributed to damage such as core hyperintensity and increased width. Little is published regarding the normal tendon, including how senescent changes and sex differences may affect the appearance. Conventional magnetic resonance imaging (MRI) techniques provide subjective analysis of tendons based on observer assessment of signal intensity and appearance. Quantitative MRI (qMRI) techniques such as T2 mapping provide an objective comparison of collagen orientation with analysis of a decay constant, T2. This study investigates age and sex related changes in the canine supraspinatus tendon using the qMRI technique of T2 mapping. STUDY DESIGN: In this study, 34 tendons of clinically sound male and female dogs (0.6-13 years) were imaged using qMRI T2 mapping techniques. Sagittal plane T2 maps of the supraspinatus tendon were depth-normalized, and profiles compared using two separate four-parameter logistic equations describing T2 mapping profiles as sigmoidal curves. Combined parameters evaluated included range of T2 values, curve steepness, vertical curve shift, lower bound of T2, upper bound of T2 and horizontal curve shift. RESULTS: A significant reduction in the most central portion of the supraspinatus tendon was found for every increased year in age (-1.56 ± 0.47 milliseconds [-2.56, -0.56, p = 0.004]). No significant difference in curve parameters was found between sexes. CONCLUSION: The reduction in T2 with age suggests a senescent change may be anticipated with the canine supraspinatus tendon.

Partial Infraspinatus Tendon Transection as a Means for the Development of a Translational Ovine Chronic Rotator Cuff Disease Model.

OBJECTIVE: Rotator cuff tendon tears are the most common soft tissue injuries in the shoulder joint. Various animal models have been described for this condition, but all current translational animal models have inherent weaknesses in their ability to generate chronically degenerated rotator cuff tendons. The objective of this study was to evaluate a partial infraspinatus tendon transection model as a means of creating a chronically degenerated rotator cuff tendon in an ovine model and compare the injury characteristics of this model to those observed in human patients with severe chronic rotator cuff tendon injuries. STUDY DESIGN: The infraspinatus tendons of six sheep were partially detached followed by capping of the detached medial section of the tendon with Gore-Tex. Human tissue samples of the supraspinatus tendon were harvested from patients undergoing primary reverse shoulder arthroplasty and served as positive controls of chronic rotator cuff tendinopathy. RESULTS: Transected sheep tendons were characterized predominantly by an acute reactive and reparative pathological process as compared with the chronic degenerative changes observed in the human tendons. In contrast, the non-transected portion of the ovine tendon showed histological changes, which were more chronic and degenerative in nature when compared with the transected tendon. CONCLUSION: Overall, histological features of the non-transected portion of ovine tendon were more similar to those observed in the chronic degenerated human tendon.

Diagnosis and treatment of infraspinatus tendon-bursa ossification in a Eurasian Dog.

A 4-year-old male Eurasian Dog presented at our veterinary clinic with a history of perpetual forelimb lameness in both thoracic limbs. In the clinical exploration, direct pressure over the infraspinatus tendon of insertion caused pain in both thoracic forelimbs and a firm band-like structure was palpable. No improvement was observed after treatment with rest, non-steroidal anti-inflammatory drugs and an intralesional injection of a long-acting glucocorticoid. Radiographic examination, ultrasonographic exploration and computed tomography were performed, identifying ossified structures lateral to the proximal humerus and an irregular roughened periosteum at the insertion and tendon of the infraspinatus muscle on both sides. There were more distinct alterations on the right thoracic limb. The imaging results led to a diagnosis of an infraspinatus tendon-bursa ossification accompanied by a chronic tendinopathy/tendovaginitis, accentuated on the right side. The dog was subjected to physiotherapy and autologous conditioned plasma (ACP) was injected into the insertion of the infraspinatus muscle of both thoracic limbs. After 5 months of physiotherapy and two injections of ACP with an interval of one week in both forelimbs, the dog showed no signs of lameness. This case report describes the diagnosis and management of infraspinatus tendon-bursa ossification in a Eurasian Dog. To the authors' knowledge, this condition has previously not been described in this breed of dog.

Extracorporeal shockwave therapy and therapeutic exercise for supraspinatus and biceps tendinopathies in 29 dogs.

Supraspinatus tendinopathy (ST) and biceps tendinopathy (BT) are common causes of forelimb lameness in large-breed dogs and have historically been treated with conservative management or surgery. Extracorporeal shockwave therapy (ESWT) and therapeutic exercise (TE) are thought to be treatment options for these conditions. The objectives of this study were to report the clinical presentations of dogs treated with ESWT for shoulder tendinopathies, to determine the association between shoulder lesion severity identified on ultrasonography or MRI and outcome, and to compare the outcomes of dogs treated with ESWT with and without TE. Medical records of 29 dogs diagnosed with shoulder tendinopathies and treated with ESWT were reviewed, and 24 dogs were diagnosed with either unilateral BT or BT and ST. None were found to have unilateral ST. Five dogs were diagnosed with bilateral disease. Eighty-five per cent of dogs had good or excellent outcomes determined by owner assessment 11-220 weeks after therapy. Outcomes were found to be better as tendon lesion severity increased (P=0.0497), regardless if ESWT was performed with or without TE (P=0.92). ESWT should be considered a safe primary therapeutic option for canine shoulder tendinopathies. Larger controlled prospective studies are needed to adequately assess these findings.