Synovial chondromatosis of the joints

There are many diseases of the musculoskeletal system and connective tissue, and these include synovial chondromatosis, which is a lesion of the inner synovial membrane of the fibrous capsule of the joints (joint capsule) in the form of benign chondrogenic metaplasia. [1]

Synovial chondromatosis (from the Greek chondros - cartilage) is also called synovial osteochondromatosis, coral joint or Lotsch syndrome, Henderson-Jones syndrome and Reichel's disease. [2]

Epidemiology

As already noted, this pathology is rarely detected, and in comparison with other joint diseases, its frequency, according to some data, does not exceed 6.5%. The male to female ratio among patients is 3: 1.

Secondary synovial chondromatosis is more common than primary. Mainly the large joints and, as a rule, the joints of the right extremities are affected.

The most common (up to 65-70% of cases) is chondromatosis of the knee joint; in second place is chondromatosis of the elbow joint (which is often bilateral); chondromatosis of the hip joint is the third most frequent, followed by chondromatosis of the shoulder joint.

Chondromatosis of the ankle joint is very rare. But less often, in isolated cases, synovial chondromatosis of the TMJ (temporomandibular joint) is detected. 

Causes synovial chondromatosis

This disease is considered quite rare, and its causes have not yet been clarified. But they are associated both with genetically determined disorders of the formation of intra-articular cartilage, and with local pathological changes in cartilage tissue during natural regeneration - with joint injuries (especially osteochondral fractures), inflammatory injuries, chronic joint diseases of a degenerative-dystrophic nature, as well as with permanent excessive loads on the synovial joints (leading to deformation of their structures and destruction of the articular surface). [3]

There is a correlation between the lesion of the synovial membrane of the joint with pronounced age-related features of the metabolism of the hyaline cartilage tissue, since most often the pathology is detected in adults, starting from 40 years and older. [4]

Read -  Development and age characteristics of bone connection in ontogenesis

In addition, possible risk factors for the development of this pathology may be of an endocrine nature, since, as is known, a number of human hormones (steroid, thyroid-stimulating, pituitary) affect the state of cartilage tissues. [5]

 

Pathogenesis

Explaining the pathogenesis of synovial chondromatosis, experts emphasize the key importance of structural changes in cartilage tissue: focal metaplastic transformation, as well as proliferation (growth) of connective tissue, that is, increased mitosis of its cells.

As a result, at the initial stage, cartilaginous (chondromic) nodules of a spherical shape, which are called cartilaginous intra-articular bodies, are formed in the synovial membrane of the joint or in the connective tissue tendon sheath. They are made up of larger and more densely grouped hyaline cartilage cells (fibroblasts and chondroblasts). [6]

At the next stage, the nodules are separated from the inner lining of the articular capsule, freely moving in the synovial fluid and receiving nutrients from it by diffusion. In fact, this is a kind of free inclusions in the articular cavity - the so-called "articular mice" (as they were previously called because of their rapid movement, reminiscent of a running mouse).

Over time, the cartilaginous bodies increase, and in 75-95% of cases, their endochondral calcification and ossification (ossification) occurs. As it turned out, with synovial chondromatosis in the intra-articular fluid, the level of chondrocalcin, a polypeptide produced by cartilage tissue cells (chondrocytes), which binds calcium and participates both in the formation of the epiphyseal plate of hyaline cartilage, and in its destruction, is significantly increased. [7]

In especially severe cases, the entire articular space can be filled with bone-cartilaginous bodies, which are able to penetrate into the surrounding tissues.

Symptoms synovial chondromatosis

At the initial stage, the pathological process is asymptomatic, and the first signs - in the form of pain in the joint when feeling it - appear when the cartilaginous bodies ossify.

Further, clinical symptoms are manifested by dull pain in the joint (first only when moving, and then at rest), its swelling and hyperthermia of the skin over the affected joint. Its mobility is significantly reduced (patients complain of joint stiffness), and movements may be accompanied by crepitus (crunching). [8]

Forms

Clinicians divide synovial chondromatosis into primary and secondary. The primary is considered idiopathic - of unknown origin, and the secondary is the result of trauma or degenerative changes in the articular cartilage in osteoarthritis. According to many orthopedists and rheumatologists, secondary synovial osteochondromatosis is a late complication of the primary form of pathology, for example, it is usually present in arthritis.

Synovial chondromatosis of the tendon sheath or bursa, identical to the primary form of pathology, can be defined as tenosynovial or bursal. Extra-articular localization of pathology, as a rule, is observed in the upper limbs, in particular, in the wrist. In this case, cartilaginous nodules are painful only on palpation and very rarely affect movement.

Multiple chondromatosis refers to multiple intraarticular or periarticular cartilaginous bodies.

Complications and consequences

Possible complications include complete blockage of the affected joint with the development of its  contracture  and a gradual decrease in the tone of the periarticular muscles.

The consequence of primary synovial osteochondromatosis can be inflammation of the synovial membrane of the joint - reactive  synovitis  or secondary deforming arthrosis (osteoarthritis) with intense joint pain.

There is a threat of the degeneration of primary synovial chondromatosis into chondrosarcoma. However, as experts note, it is possible to misidentify malignant transformation due to the presence of atypical cells inherent in benign chondrogenic metaplasia.

Diagnostics synovial chondromatosis

Standard  diagnostics of joints is performed , where visualization plays a key role, since clinical symptoms are nonspecific, and laboratory tests - except for  general clinical analysis of synovial fluid  and biopsy of the tissue of the synovial membrane of the articular bursa - are absent. [9]

Only instrumental diagnostics can visualize cartilaginous nodules in the joint capsule :  ultrasound of the joints , contrast radiography -  arthrography of the joints , magnetic resonance imaging (MRI). [10]

A conventional X-ray can show only calcified chondromic bodies, and with their ossification, X-ray signs consist in the display in the image of the presence in the bursa or joint of a certain number of oval / round bodies with clear outlines. Narrowing of the intra-articular space and degenerative changes in the articular surfaces (in the form of subchondral sclerosis, the presence of osteophytes, erosion of the articular surface in the form of a depression) can also be displayed. [11], [12]

More information in the article - X -  ray signs of bone and joint diseases

Differential diagnosis

Differential diagnosis of synovial chondromatosis should include: synovitis, including pigmented villonodular (villous-nodular); tenosynovitis; synovial hemangioma; osteoarthritis; periarticular tumor calcification and periarticular melorheostosis (Leri's disease). And, of course, chondrosarcoma, since, according to clinical observations, in synovial chondromatosis, the degree of cellular atypia may be higher than in chondrosarcoma.

In addition, it is necessary to differentiate cartilaginous nodes in synovial chondromatosis and smaller fibrinous rice bodies formed in the joint capsule in rheumatoid arthritis, joint tuberculus or chronic bursitis.

Treatment synovial chondromatosis

Only surgical treatment, which is carried out using arthroscopy  or arthrotomy (opening of the joint cavity), can free the capsule surrounding the joint from the bone-cartilaginous bodies . But in almost 23% of cases, there are postoperative relapses.       

Partial or total synovectomy - surgical excision of the synovium in an open way - is most often resorted to if the chondrogenic metaplasia of the synovium is recurrent and persistent. [13]

After surgical interventions for the functional restoration of the joint, physiotherapy is prescribed. [14]Read more in the publication -  Physiotherapy for joint diseases

Prevention

There are no specific measures for the prevention of focal metaplastic transformation of cartilage tissue.

Doctors advise avoiding injuries, dosing loads on the synovial joints, and consuming  foods to restore cartilage, joints and ligaments .

Forecast

The long-term prognosis for patients with synovial chondromatosis directly depends on the affected joint, the extent of its damage, and the recurrence of the disease after surgery. Periodic examinations will be required to prevent recurrence of cartilage metaplasia or the development of osteoarthritis.