Keywords:
Hyperplasia / Hypertrophy, Calcifications / Calculi, Arthritides, Education, Plain radiographic studies, MR, CT, Musculoskeletal system, Musculoskeletal soft tissue, Musculoskeletal joint
Authors:
B. Sharif, M. Khoo; Stanmore/UK
DOI:
10.1594/essr2018/P-0065
Background
Synovial chondromatosis refers to the presence of intra-articular cartilaginous loose bodies,
which may or may not be calcified/ossified.
It is known by several other names,
namely synovial osteochondromatosis,
synovial chondrometaplasia,
articular ecchondrosis and synovial chondrosis.
A distinction should be made between primary and secondary synovial chondromatosis.
It should also be differentiated from other intra-articular conditions,
which may have a similar appearance on imaging.
Primary synovial chondromatosis (PSC) is a relatively uncommon condition,
(incidence of 1:100,000) that typically affects patients in the third to fifth decades of life.
Men are 2-4 times more frequently affected than women. This condition usually occurs in an otherwise normal joint and can less commonly occur in extra-articular synovially lined sites e.g.
tendon sheaths and bursae. The underlying pathological process for intra and extra articular disease is identical.
Pathophysiology
PSC occurs as a result of a neoplastic process where there is subsynovial cartilage neoplasia,
synovial hyperplasia and the production of cartilaginous nodules (chondromas) that continue to grow in size due to nourishment from synovial fluid.
Some of these chondromas can calcify and may progress to ossification.
Milgram described three distinct phases of articular disease which can occur:
- Initial phase - metaplastic formation of cartilaginous nodules in the synovium.
- Transitional phase - detachment of those nodules and formation of free intra-articular bodies.
- Inactive phase - resolution of synovial proliferation but loose bodies remain in joint but may increase in size.
Clinical presentation
Patients usually present with insidious,
gradually progressive non-specific pain,
swelling and restricted range of motion of the affected joint(s).
The time from the onset of symptoms to diagnosis is around 5 years.
Physical examination may reveal a swollen joint with joint line tenderness,
crepitus and locking.
It is invariably mono-articular,
although polyarticular disease occurs in 5-10% of cases.
The most commonly affected joint is the knee (50-65% of cases).
The hip,
elbow,
shoulder and ankle are also commonly affected.
Less commonly involved sites include the metacarpophalangeal,
radiu-ulnar,
temporomandibular,
acromioclavicular and proximal tibiofibular joints.