Kiriti Sarkar

Calcifying tendinitis: a new concept of its pathogenesis.

To elucidate the pathogenesis of calcifying tendinitis, clinical and morphological investigations were done on 46 surgically treated cases. Contrary to the prevalent concept of degeneration preceding dystrophic calcification, we found no evidence for an active or a healed degenerative process. The affected tendon was transformed into fibrocartilage with a predilection for calcification. The formative phase of calcification was followed in course of time by a resorptive phase during which the deposits were surrounded by phagocytosing cells. There was a concomitant proliferation of vascular channels. We found a significant correlation between severe pain and histological signs of resorption. The pathogenetic mechanism of calcifying tendinitis should be reassessed as a unique disorder of the musculotendinous cuff.

Structural and functional changes in the canine shoulder after cessation of immobilization

The functional and structural consequences of remobilization of the glenohumeral joint after 12 weeks of immobilization were studied in 10 beagle dogs. The dogs were grouped in pairs: 2 were used as controls, and in 8 others 1 forelimb was immobilized. At the end of 12 weeks, 2 dogs in the experimental group were euthanized, as were the 2 dogs used as controls. The cast was removed from the other 6 dogs, and the remobilized animals were euthanized in pairs at the end of 4, 8, and 12 weeks. It was found that after 12 weeks of immobilization, the passive range of motion was markedly impaired, intraarticular pressure was raised during movements, and the filling volume of the joint cavity was reduced. Histologically, the capsule showed synovial lining hyperplasia and vascular proliferation in the wall. Immunohistochemical labeling for collagen Types I and III failed to show an increase of fibrous collagens in the capsular wall. Both the functional and structural changes were unaltered after 4 weeks of remobilization, but after 8 weeks they began to reverse, and they returned to normal levels after 12 weeks. Both functional and structural changes after 12 weeks of immobilization of the uninjured glenohumeral joint are reversible by remobilization. The collagen composition of the capsule seems unrelated to the degree of capsular contraction that occurs during 12 weeks of immobilization and subsequent remobilization.

The ultrastructure of the coracoacromial ligament in patients with chronic impingement syndrome

In an ultrastructural study of the cells and matrix of the coracoacromial ligament (CAL) in 11 patients with impingement syndrome (IS), the cells appeared variegated, in contrast to those in normal CALs. Many showed degenerative changes such as lipid inclusions in the cytoplasms or swelling of cytoplasmic organelles, especially in the vicinity of fibrin exudate where the collagenous matrix disappeared. However, some cells had increased cytoplasmic organelles, including an elaborate Golgi apparatus, indicating enhanced synthetic activity. The matrix, instead of consisting of packed collagenous fibers of fairly uniform diameter as seen in the normal CAL, contained collagen fibers of varying diameters and microfibrils. The ultrastructural features of both the cells and the matrix were suggestive of chronic effects of strain on the ligament. In patients with chronic IS, the CAL has been implicated as the likely cause of impingement when no significant bony or articular abnormality exists. This was not substantiated by the present findings. The changes in the CAL in IS are possibly secondary, and are probably induced by alterations in soft-tissue structures of the subacromial compartment.

Estimation of total collagen and types I and III collagen in canine rotator cuff tendons.

Abstract. The collagen composition of the supraspinatus, infraspinatus, and subscapularis tendons, which form part of the rotator cuff of the shoulder, was determined. Tendons were obtained from adult, male beagle dogs and total collagen was estimated by measurement of hydroxyproline. There was little variation in collagen content among the three major cuff tendons and the quantity approximated that cited in the literature for other tendons. However, the collagen content in the insertion zone of the supraspinatus tendon was significantly higher than in the tendon proper. NaCl fractionation of supraspinatus collagen indicated that type I was the predominant collagen but significant amounts of type III and possibly some type II and type V were also present. Interestingly, there appeared to be more type III collagen in the insertion zone than in the tendon proper, cyanogen bromide digestion and peptide mapping confirmed this finding. The differential collagen composition of the supraspinatus tendon may contribute to the high incidence of tear that is associated with this rotator cuff tendon.

Collagen type III in rotator cuff tears: An immunohistochemical study

The presence and distribution of collagen type III, which represents newly formed fibers of early repair, were investigated in four surgically removed en bloc specimens of complete rotator cuff tears. The patients were two men and two women who ranged in age from 63 to 71 years. They had received preoperative, conservative treatment for a period varying from 3 months to 3 years. For the identification of the collagen immunohistochemical staining was performed by the peroxidase-antiperoxidase method with the use of monoclonal antibody against human collagen type III. Collagen type III was discernible throughout the tendon proper in all specimens. It often occurred in association with proliferating fibroblastic cells. Collagen type III was abundant only in the perivascular spaces of the much thickened bursal wall that extended over the margins of the tear. We concluded that the presence of collagen type III indicates the need for a continued attempt for repair at the site of the tear, including both bursal and tendinous tissues.

Ultrastructure of the subacromial bursa in painful shoulder syndromes

In order to determine if inflammation of the subacromial bursa or “bursitis” is as common an occurrence as believed in painful conditions of the shoulder, eight bursae were obtained during surgery from 3 cases of calcifying tendinitis, 2 of tight coracoacromial ligament, 2 of rotator cuff tear and 1 of acromioclavicular osteoarthritis. In the cases of calcifying tendinitis, tight coracoacronial ligament and rotator cuff tear the morphological changes mainly consisted of a numerical increase in cells throughout the bursal wall along with proliferation of endothelial cells in the vascular channels. All of the cells including the endothelial had densely packed, intermediate type filaments in their cytoplasm but no appreciable diminution of metabolic organelles. Lipid droplets were abundant in the extracellular connective tissue of the bursae from the cases with rotator cuff tear. In contrast to the other cases, the bursa from the case of acromioclavicular osteoarthritis showed widespread fibrin deposition in association with cell necrosis. In none of the cases did inflammatory leukocytic cells infiltrate bursal tissue. We conclude, that the subacromial bursa tends to undergo proliferative or degenerative changes in rotator cuff tendinopathies but bursal inflammation with polymorphonuclear cell infiltrate does not occur commonly.

Effects of Immobilization on the Capsule of the Canine Glenohumeral Joint: A Structural Functional Study

The effects of immobilization on the function of the glenohumeral joint and its capsule were investigated in eight beagle dogs. One foreleg of each animal was immobilized in a spica cast, and the dogs were euthanized after 4, 8, 12, and 16 weeks of immobilization in groups of two. The contralateral limb and the forelegs of two normal beagles were used as controls. At the time of euthanasia, the range of motion, intraarticular filling volume during passive movements of the joint, and intraarticular filling volume to rupture the capsule were measured. The synovium, including the capsule and the subscapular bursa, were examined histologically. In the immobilized limb, there was progressive restriction in the range of motion with increases in intraarticular pressure, and the filling volume that was required to cause a rupture of the capsule diminished. Morphologically, the capsule and the subscapular bursa showed focal adhesions. Thus, it appeared that immobilization of these canine forelimbs produced changes in the glenohumeral joint that resembled those of frozen shoulder in humans.

Ultrastructure of the common extensor tendon in tennis elbow

In patients with tennis elbow, the common extensor tendon showed a pronounced reactive change consisting of mesenchymal cell proliferation along with aggregates of newly formed vascular channels. When studied ultrastructurally, many of the mesenchymal cells adjacent to the vascular channels were surrounded by a basal lamina, which is not normally seen around tenocytes. The cytoplasm of these cells showed features of both endothelial cells and tenocytes. It thus appeared, that the endothelial cells of the newly formed vascular channels were the source of proliferating mesenchymal cells differentiating toward tenocytes, and together they represented an intrinsic healing mechanism in the tendon.

Embryonal rhabdomyosarcoma of the prostate. An ultrastructural study

An ultrastructural study of an embryonal rhabdomyosarcoma arising from the prostate of a 9‐year‐old boy is reported. Cross striations in neoplastic cells were difficult to find under the light microscope. The electron microscope, however, revealed large cells with poorly formed but easily recognizable myofibrils. There were numerous small cells devoid of myofilaments in the vicinity as well. Their cytoplasmic contents were of two types: one type had abundant free ribosomes while the other had rough endoplasmic reticulum and Golgi apparatus. Irrespective of type, the small cells were associated either with the large cells containing myofilaments or with collagen fibrils. From their disposition and ultrastructural characteristics, it was difficult to determine which type of the small cells represented the precursor of the large cells containing myofibrils and which belonged to the stromal component of the neoplasm.

An algorithm for shoulder pain caused by soft-tissue disorders

Painful shoulders are commonly caused by disorders of periarticular soft tissues, especially rotator cuff tendinopathies. In contrast to arthritic conditions of the shoulder, soft-tissue disorders can present a diagnostic dilemma that often results in the use of such nonspecific or unproved terminologies as periarthritis or bursitis. To promote an efficient use of investigative studies necessary to arrive at a proper diagnosis, an algorithm can serve as a guide for clinicians in the diagnosis and management of common, nonarthritic conditions of painful shoulders.