Patellar tendinopathy: preliminary surgical results

Imaging of calcific tendinopathy: natural history, migration patterns, pitfalls, and management: a review

Calcific tendinopathy is characterized by the deposition of calcium hydroxyapatite crystals in various tendons of the body. Terms like calcium tendinitis, tendinosis, and tendinopathy are used interchangeably. Calcific tendinopathy is a common and well-documented ailment in the literature. Although common, the natural history, aetiology, and progression of calcific tendinitis are poorly understood. The treatment options include conservative and interventional measures. However, these measures cannot be applied as a blanket and are often tailored depending on the stage/phase of the disease. Out of the recognized stages of the disease, the resorptive stage causes the utmost symptoms when the calcium is rather soft and unstable. During this stage, the calcium may migrate beyond expected resorption and get deposited in the adjacent tissues contiguous with the calcium focus. The common destinations include bursal migration, intraosseous migration, muscular migration, and other less common migration sites. Such atypical presentations can lead to dilemmas in the diagnosis, prolongation of the diagnostic pathway, unwarranted apprehension, and treatment delay. Radiologists' role in this situation is to correctly recognize the imaging findings of atypical presentations of calcific tendinopathy and prevent unnecessary diagnostic and interventional studies. In this review article, we describe the pathogenic pathway and natural history of calcific tendinopathy from a radiologist's perspective and discuss different migratory patterns of calcium in calcific tendinopathy not only around the shoulder but also in other areas of the body on different imaging modalities. We also show a few examples of mimics and pitfalls on imaging. Finally, we discuss the appropriate management option of this condition.

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

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

Calcific Tendinopathy Atypically Located Outside the Rotator Cuff: A Systematic Review

BACKGROUND AND PURPOSE

Calcific tendinopathy is a common cause of painful shoulder easily identified with ultrasound or conventional radiography. Although the rotator cuff is by far the most common location of the disease and diagnostic or treatment strategies are well known in clinical practice, a lack of awareness characterizes the assessment of the other sites affected by this condition; consequently, the risk of underestimating the prevalence of atypical non-rotator cuff calcific tendinopathy is high. This may lead to expensive or invasive diagnostic exams and/or inappropriate treatment, whereas the condition is usually self-limited. The present study aims at analysing the frequency of calcific tendinitis in uncommon sites, in order to fill a gap in knowledge and awareness regarding non-rotator cuff calcific tendinopathy, thus avoiding improper clinical choices and helping to identify this condition.

METHODS

This systematic review was conducted following the PRISMA guidelines. We performed a search on Pubmed and Scopus databases concerning atypically sited extra-rotator cuff calcific tendinopathy published since 1950.

RESULTS

The research found a total of 267 articles and 793 non-rotator cuff cases of calcific tendinopathy registered. The spine (213 – 26.86%), foot and ankle (191 – 23.95%), and hip (175 – 22.06%) appeared to be the most common sites of calcific tendinopathy after the rotator cuff, whereas the longus colli C1-C2 (204 – 25.72%), Achilles (173 – 21.81%), and rectus femori (61 – 7.69%) were the most commonly affected tendons.

CONCLUSION

A better awareness of this condition in several different sites of the body than the rotator cuff could avoid unnecessary choices both in assessment and treatment.

Non-rotator cuff calcific tendinopathy: ultrasonographic diagnosis and treatment

Calcific tendinopathy is a condition that is related to the deposition of calcium, mostly hydroxyapatite crystals, within the tendons. The shoulder and the hip are commonly affected joints, but calcific tendinopathy may occur in any tendon of the body. While there is an extensive literature on the ultrasound diagnosis of calcific tendinopathy of the shoulder, there are only sporadic reports on other sites. This review combines the experience of our centers and a thorough analysis of the literature from the last 45 years (1972-2017) in order to highlight the localizations beyond the rotator cuff, their ultrasound characteristics and therapeutic possibilities.