Degenerative Tendinopathy Research Articles

Current concepts in the management of tendon disorders

Primary disorders of tendons are common and constitute a high proportion of referrals to rheumatologists. Certain tendons are particularly vulnerable to degenerative pathology; these include the Achilles, patella, elements of the rotator cuff, forearm extensors, biceps brachi and tibialis posterior tendons. Disorders of these tendons are often chronic and can be difficult to manage successfully in the long term. Significant advances have been made in understanding the pathophysiology of these conditions. Histopathological evidence, together with advances in imaging techniques, has made us more appreciative of the degenerative (rather that inflammatory) nature of these conditions. Additionally the presence of neovascularization is now well-recognized in long-standing tendinopathy. We review the mechanical, vascular and developing neural theories that attempt to explain the aetiology of degenerative tendinopathy. We also explore theories of why specific tendons (such as the Achilles and supraspinatus tendons) are particularly prone to degenerative pathology. Traditionally, treatments have placed a heavy emphasis on anti-inflammatory strategies, which are often inappropriate. Recently, however, significant advances in the practical management of tendon disorders have been made. In particular the advent of 'eccentric loading' training programmes has revolutionized the treatment of Achilles tendinopathy in some patients. This concept is currently being extended to include other commonly injured tendons. Other current treatments are reviewed, as are potential future treatments.

The Orthopaedic Research Institute–Tennis Elbow Testing System: a modified chair pick-up test—interrater and intrarater reliability testing and validity for monitoring lateral epicondylosis

Lateral epicondylosis is a degenerative overuse tendinopathy involving the extensor tendons of the forearm, predominantly the extensor carpi radialis brevis, in the region of the lateral epicondyle of the elbow. The Orthopaedic Research Institute–Tennis Elbow Testing System (ORI-TETS) is designed to record objective measurements of force generated with a simulated chair pick-up test. Interrater reliability of the ORI-TETS was excellent, with high intraclass correlation coefficients (ICCs) for right arm mean peak force of 0.93, left arm mean peak force of 0.84, right arm mean total force of 0.93, and left arm mean total force of 0.86. The ORI-TETS also demonstrated excellent intrarater reliability, with ICCs ranging from 0.9 to 0.97. The relative technical error of the ORI-TETS for all measurements ranged from 5.8% to 7.2%. Testing patients with lateral epicondylosis (N = 16) and comparing analog pain scores with ORI-TETS testing demonstrated a strong negative relationship between the two parameters (Spearman ρ, −0.87 to −1.0). Thus, the ORI-TETS is a reliable and reproducible testing system for the forearm extensors. The testing system is inexpensive, takes 5 minutes to perform, and demonstrates good predictive value for objectively assessing patients with lateral epicondylosis. This system could be used for routine clinical monitoring of patients with lateral epicondylosis.

Magnetic resonance imaging of Achilles tendon in patients with rheumatoid arthritis.

The authors characterize the appearance of the Achilles tendon in patients with rheumatoid arthritis and differentiate this appearance from degenerative tendinopathy in patients with chronic pain of the heel using magnetic resonance (MR) imaging. Thirty patients with rheumatoid arthritis and 28 patients with chronic pain of the heel underwent MR imaging of the ankle and foot. Three radiologists independently assessed the MR images with respect to size, shape, and intratendinal signal characteristics of the Achilles tendon. The Achilles tendon was considered abnormal on MR imaging when intratendinous signal alterations or an anteroposterior measurement greater than 8 mm was seen. Physical examination of the Achilles tendons was accomplished in both groups. Operation confirmed the diagnosis of 13 patients in the second group with chronic pain of the heel. The Achilles tendon of 83% of patients with rheumatoid arthritis demonstrated various intratendinous patterns (longitudinal, reticular, nodular) of intermediate signal intensity on all pulse sequences on MR imaging. Ninety percent of patients with rheumatoid tendinopathy showed no enlargement of the anteroposterior diameter of the Achilles tendon. In addition, all patients with rheumatoid arthritis had findings compatible with an inflammation of the retrocalcaneal bursa on MR imaging, whereas none of the patients with tendinopathy associated with chronic heel pain had retrocalcaneal bursitis. All patients, however, had enlargement of the anteroposterior diameter of the Achilles tendon. Seventy-nine percent showed various intratendinous lesions of intermediate signal intensity on all pulse sequences. Twenty-one percent of patients had an enlargement of the Achilles tendon without intratendinous changes. Rheumatoid tendinopathy can be distinguished from degenerative tendinopathy in patients with chronic pain of the heel with MR imaging. Inflammation of the retrocalcaneal bursa and the absence of enlargement of the tendon combined with the presence of intratendinous signal alterations are characteristic findings of rheumatoid tendinopathy.

Patellar Tendon Ruptures.

Rupture of the patellar tendon is a relatively infrequent, yet disabling, injury, which is most commonly seen in patients less than 40 years of age. It tends to occur during athletic activities when a violent contraction of the quadriceps muscle group is resisted by the flexed knee. Rupture usually represents the final stage of a degenerative tendinopathy resulting from repetitive microtrauma to the patellar tendon. This injury may also occur during less strenuous activity in patients whose tendons are weakened by systemic illness or the administration of local or systemic corticosteroid medications. The diagnosis is made on the basis of the presence of a painful, palpable defect in the substance of the tendon; an inability to completely extend the knee against gravity; and the existence of patella alta confirmed by lateral radiographs. Ultrasonography and magnetic resonance imaging are useful in identifying a neglected rupture, as well as when the diagnosis is in question or an intra-articular injury is suspected. The prognosis after a patellar tendon rupture depends in large part on the interval between injury and repair. Surgery soon after the injury is recommended for optimal results. This is best accomplished by accurate reapproximation of the ruptured tendon ends, repair of the torn extensor retinacula, and placement of a reinforcing cerclage suture. An aggressive rehabilitation program, emphasizing early range-of-motion exercises, protected weight bearing, and quadriceps strengthening, will enhance the results of surgery. Patients who undergo delayed repair are at risk for a compromised result secondary to loss of full knee flexion and decreased quadriceps strength, although a functional extensor mechanism is likely to be reestablished.

Histopathological changes preceding spontaneous rupture of a tendon. A controlled study of 891 patients.

We evaluated specimens obtained from the biopsy of spontaneously ruptured tendons in 891 patients who were treated between 1968 and 1989. The specimens, which were removed at the time of repair, included 397 Achilles tendons, 302 biceps brachii tendons, forty extensor pollicis longus tendons, eighty-two quadriceps tendons and patellar ligaments, and seventy other tendons. Age and sex-matched control specimens, from 445 tendons taken at the time of death from the cadavera of previously healthy individuals who died accidentally, also were obtained and evaluated. The histopathological analyses of the specimens included light and polarized light microscopy and scanning and transmission electron microscopy. A healthy structure was not seen in any spontaneously ruptured tendon, but two-thirds of the control tendons were structurally healthy (p less than 0.001). There were characteristic histopathological patterns in the spontaneously ruptured tendons. Most (97 per cent) of the pathological changes were degenerative; they included hypoxic degenerative tendinopathy, mucoid degeneration, tendolipomatosis, and calcifying tendinopathy, either alone or in combination. These changes were also found in 34 per cent of the control tendons, but significantly less frequently (p less than 0.001). In the other twenty-six ruptured tendons (3 per cent), the pathological change was an intratendinous foreign body, rheumatoid tendinitis, a xanthoma, a tumor, or a tumor-like lesion such as an intratendinous ganglion. The findings clearly indicate that, at least in an urban population, degenerative changes are common in the tendons of people who are older than thirty-five years and that these changes are associated with spontaneous rupture.

Acromial Enthesopathy and Rotator Cuff Tear

Changes of the coracoacromial ligament (CAL) at its insertion into the undersurface of the acromion were studied radiologically and histologically in 76 autopsy specimens. Two changes were noted: (1) a downward, bony projection of the acromion, an anatomic variant limited to the area covered by the CAL, which might reduce the height of the subacromial compartment, and (2) a thickened layer of fibrocartilage, constituting a potential cause for narrowing of the subacromial space. The former might act as a predisposing factor for the impingement syndrome, whereas the latter could develop in response to pressure from constituents of the subacromial compartment. The acromial spur was a result of enchondral bone formation. A possible correlation between these changes and rotator cuff tears was investigated. The incidence and severity of cuff tears increased with age. However, there was no correlation between aging and degenerative changes of the undersurface of the acromion, except possibly in very advanced cases. Rotator cuff tears are unlikely to be initiated by impingement; rather, they develop as an intrinsic degenerative tendinopathy.

Alterations in Dry Mass Content of Collagen Fibers in Degenerative Tendinopathy and Tendon-Rupture

The dry mass concentration and collagen fiber morphology of intact, as well as of degenerated and ruptured human Achilles, biceps brachii, extensor pollicis longus and quadriceps tendons, were determined by using the interference microscopical technique. The variation in the collagen fiber thickness was demonstrated in different intact tendons, the fibers being largest in the Achilles and smallest in the extensor pollicis longus tendons. However, the intact tendons exhibited only thick collagen fibers. In the degenerative tendinopathies an increase of the dry mass content was observed, being especially marked in calcifying tendinopathy. In the degenerated tendons the average collagen fiber diameter had decreased, and two clearly distinct populations of thick and thin fibers were observed. The dry mass content of the thick fibers was significantly greater than that of the thin fibers. The present results demonstrate striking changes in the collagen and its dry mass content in degenerative tendinopathy, thus also increasing the susceptibility to ruptures.

Fine structural alterations of collagen fibers in degenerative tendinopathy.

Fine structural alterations of collagen fibers were analyzed in 29 ruptured tendons. The most frequent alterations were longitudinal splitting, disintegration, angulation, and the so-called "Knickdeformation" of the collagen fibers. All these phenomena were considered to be the consequences of stress fatigue and mechanical injuries of fibers.

Hypoxic alterations of tenocytes in degenerative tendinopathy.

The authors examined 34 tendons under the electron microscope, excised within 48 h after rupture of the tendons. The tendons did not exhibit any signs of inflammation or lipomatosis, but fine-structurally marked hypoxic alterations in the tenocytes could be seen. The degenerative (hypoxic tendinopathy appears in three phases, and the hypoxic lesions of the tendon occur at multiple foci or diffusely, and the various phases can exist simultaneously.