Bursae, Tendons and Ligaments

The entheses: histology, pathology, and pathophysiology

The entheses are the sites of attachment of ligaments, tendons, and joint capsules to bone. Their ubiquitous distribution throughout the body explains the considerable clinical and radiological polymorphism of entheseal diseases. In addition to aging and mechanical factors, many disorders related to a vast array of pathophysiological mechanisms can produce entheseal disease. The spondyloarthropathies provide the most striking examples of entheseal involvement in inflammatory joint disease. Over the last few decades, major advances have shed light on the biochemical composition of the entheses, their histological features, their mechanical role, and their evaluation by ultrasonography and magnetic resonance imaging. These new insights have generated valuable hypotheses about the pathogenesis of spondyloarthropathies.

Advances in the understanding of entheseal inflammation

The importance of enthesitis in the pathogenesis of spondyloarthropathy (SpA) is now well recognized. Several entheses comprise more than simply the insertion site, and they are part of a complex biomechanical organ to resist shear and compression. It is also evident that tendons that wrap around bony pulleys form an integral part of joint capsules, and share, along with imaging abnormalities and histopathologic changes, common anatomic, histologic, and biomechanical features with classically defined entheses. Researchers have called these regions of tendons functional entheses. Furthermore, certain synovial joints have much in common with classic entheses--most notably those lined with fibrocartilage rather than hyaline cartilage. These observations provide a unifying anatomic basis for SpA. Enthesitis is associated with underlying osteitis, whether mechanically induced or inflammatory-related--with the extent of osteitis determined by the human leukocyte antigen-B27 gene. Until recently, there was no effective therapy for resistant enthesitis, but it is now evident that enthesitis responds well to biologic blockade with anti-tumor necrosis factor. Unraveling the pathogenic basis of enthesitis will have important implications for understanding and defining therapies in SpA.

Baker's cysts mimicking the symptoms of deep vein thrombosis: diagnosis with venous duplex scanning

PURPOSE

The purpose of this study was to determine the incidence and characteristics of Baker's cysts discovered during venous duplex examinations to rule out deep vein thrombosis (DVT).

METHODS

We reviewed the vascular laboratory charts of patients found to have Baker's cysts during venous duplex studies to rule out DVT from October 1988 through December 1995.

RESULTS

Ninety-five (3.1%) of 3072 patients who underwent venous duplex studies were found to have 111 Baker's cysts. Seven of the 95 had coexistent DVT. Ten patients had ruptured cysts, whereas six patients had cysts that compressed the popliteal vein.

CONCLUSION

The presentation of DVT and that of a Baker's cyst are similar enough to be difficult to distinguish by clinical examination. Careful examination of the popliteal fossa should be performed during venous duplex examinations regardless of the indication for the study.

Sensory nerve supply in the human subacromial bursa

The subacromial bursa is the major component of the subacromial gliding mechanism. The neural elements of the subacromial bursa obtained from specimens that underwent autopsy and surgery were investigated by the silver impregnation and immunohistochemical methods with antisera to substance P and calcitonin gene-related peptide; which are considered to be involved in nociceptive transmission, and protein gene product 9.5. Free nerve endings, Ruffini endings, Pacinian corpuscles, and two kinds of unclassified nerve endings were observed. Most of these receptors were observed of the roof side of the coracoacromial arch, which is exposed to stress because of the impingement. A delta and C fibers, thought to be nerve fibers of free nerve endings, were immunoreactive to substance P and calcitonin gene-related peptide. On the other hand, thick fibers thought to originate in encapsulated mechanoreceptors were not immunoreactive to substance P. The subacromial bursa receives nociceptive stimuli and proprioception and seems to regulate appropriate shoulder movement.

Septic bursitis

Nine cases of septic bursitis are presented, and the literature on the subject comprehensively reviewed, with an emphasis on the clinical manifestations of septic bursitis in various anatomic locations. Physical activities associated with increased susceptibility to septic bursitis and systemic conditions that increase the severity of septic bursitis are catalogued. Analysis of the microbiology of cases reported in the literature demonstrates that greater than 80% of cases of septic bursitis are caused by Staphylococcus aureus and other gram-positive organisms. However, a wide variety of gram-negative microorganisms, fungi, and other infectious agents have been reported to cause septic bursitis and may lead to complications in diagnosis and treatment. The nine cases reported here demonstrate the potential severity of septic bursitis and emphasize that significant systemic complications may result from this common musculoskeletal infection. Indications for hospitalization and/or intravenous antibiotic therapy for septic bursitis include the presence of fulminant local infection, evidence for systemic toxicity, or infection in an immunocompromised patient. Patients who fail to respond to intravenous antibiotics and percutaneous aspiration of the bursa may require surgical drainage or bursectomy by one of several methods that have been proposed. There is some recent evidence that intrabursal corticosteroid injection for therapy of nonseptic subcutaneous bursitis may be more effective than systemic antiinflammatory medication or simple bursa aspiration.

Painful shoulder syndromes: diagnosis and management

Painful shoulder conditions are common primary care problems. Providers should learn the topographical landmarks about the shoulder and understand shoulder mechanics. A careful clinical evaluation will usually provide a likely diagnosis. In unclear cases with marked pain, weakness, and reduced mobility, or with a suspected rotator cuff tear or rupture, arthrography or MRI will usually establish a diagnosis. Therapy of bursitis/tendinitis consists of a steroid injection into the inflamed subacromial area or a 14-day trial of an NSAID. Therapy of bicipital tendinitis, largely empiric because definitive studies are unavailable for any specific treatment, includes judicious peritendinous steroid injections and avoiding aggravating activities. In the management of patients with suspected tendon tears or rupture, primary care practitioners can confirm the diagnosis by ordering MRI or arthrography before referring these patients to an orthopedist for definitive surgical therapy. Optimal management of adhesive capsulitis remains unclear, but an intraarticular steroid injection appears beneficial at least in temporarily diminishing pain. Pendular motion exercising is also an integral part of therapy. Deleterious effects of peribursal or intraarticular steroid infiltration appear minimal; but injections into the tendon or frequent, repetitive injections are contraindicated. Each shoulder condition has a variable course, depending on the structure(s) and extent of involvement.

Long-term follow-up of corticosteroid injection for traumatic olecranon bursitis

Forty-seven patients with traumatic olecranon bursitis were evaluated after a mean follow-up of 31 months (range 6 to 62 months). Twenty-two patients treated with bursal aspiration had delayed recovery and no complications of therapy. Twenty-five patients treated with intrabursal injection of 20 mg of triamcinolone hexacetonide had rapid recovery, usually within one week, but suffered complications such as infection (3 cases), skin atrophy (5 cases), and chronic local pain (7 cases). Since spontaneous resolution can be expected, a conservative approach is suggested in the treatment of traumatic olecranon bursitis.

Hyaluronic acid content of deep and subcutaneous bursae of man

To provide a comparison of the contents of subcutaneous and deep bursae we dissected these structures from unfixed cadavers without apparent joint disease. No free fluid was found within any olecranon or prepatellar bursae (examples of subcutaneous bursae), while viscous fluid was invariably present in the (deep) retrocalcaneal bursae. The hyaluronic acid content of the washings of 5 rectrocalcaneal bursae ranged from 142 to 591 nmol hexosamine (mean = 281 nmol hexosamine). In contrast, the hyaluronic acid content of 4 olecranon bursae was much lower (range 35-72 nmol, mean 53 nmol hexosamine), and hyaluronate was not detected in washings from either of 2 prepatellar bursae. The greater hyaluronate content of the retrocalcaneal bursae did not appear to be due to a greater surface area, since on the basis of calculations made from plaster casts the surface areas of the olecranon and prepatellar bursae were approximately 3 times and 2 times, respectively, greater than that of the retrocalcaneal bursae. The data suggest that, although hyaluronic acid may lubricate deep bursae, other factors may be more important in reducing friction within superficial bursae.

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.

Traumatic olecranon bursitis. Radiologic observations

The affected elbow of 28 patients with traumatic olecranon bursitis was radiographically compared with the homologous elbow of 28 matched controls. Olecranon spurs, amorphous calcium deposits, or both, were present in 16 patients and 4 controls (p less than 0.01). Air was injected in the bursa in 12 additional patients. Nodules in the bursal floor were noted in 10, and the bursa was partially septated in 8. Olecranon spurs, present in 6 patients, corresponded to the insertion of the triceps tendon. With elbow flexion the bursa flattened and lengthened while the olecranon process glided distally beneath the bursal floor.