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Synovial Osteochondromatosis
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Contents
Other Names
- Synovial Chondromatosis
- Synovial Osteochondromatosis (SOC)
- Primary Synovial Chondromatosis
- Primary Synovial Osteochondromatosis
- Synovial Chondrometaplasia
- Reichel Syndrome
Background
- This page refers to Synovial Chondromatosis (SOC), a rare proliferative disease of the synovium associated with cartilage metaplasia that results in multiple intra-articular loose bodies.
History
- First described in 1558 in the knee by Ambrose (need citation)
- In 1813, Laennac described intra-articular loose bodies arising from subsynovial tissues (need citation)
- First termed Synovial Osteochondromatosis in 1958[1]
Epidemiology
- Incidence
- Usually affects young adults, age 30 to 50[4]
- Usually unilateral, bilateral in about 5% to 10% of cases[5]
Pathophysiology

Synovial osteochodromatosis of the elbow and ankle[6]

A thirty-two-year-old man with malignant transformation of SOC of the right shoulder into chondrosarcoma[7]
- General
- Rare proliferation of cartilage within the synovium
- Results in intra-articular loose bodies, less commonly in tendon sheaths and bursae
- Mild disease is may be non surgical while more significant symptoms require surgery
- Location
- Commonly affects diarthrodial weight bearing joints
- Knee is most commonly affected (~50% to 70%)
- Followed by other large joints including hip (20%), elbow, and shoulder
- It has also been reported in the ankle, wrist and other smaller joints
- Diagnosis
- Often delayed
- Average time from symptom onset to diagnosis of 5 years (need citation)
Etiology
- General
- Unknown
- Debate as to whether it is metaplastic or benign neoplastic disease
- Benign neoplastic disease currently favored as etiology of SOC[8]
- Mechanism
- Associated with cartilage metaplasia within the synovial membrane
- Metaplastic synovium organizes into nodules
- Progressive enlargement and ossification occur with time
- If not treated, growth continues and they become larger, more calcified
- Results in multiple intra-articular loose bodies
- Ranges from synovial tissue to firm nodules of cartilage
Risk Factors
- Demographic
- 2:1 Male to female ratio (need citation)
- Genetic
- Chromosome 6 abnormalities[9]
Differential Diagnosis
- Trauma-related:
- Fracture with avulsed fragment
- Fragmentation of meniscus with calcification
- Degenerative joint disease related
- Degenerative joint disease with detached spur
- Synovial proliferation:
- Pigmented villonodular synovitis
- Neoplastic:
- Synovial chondrosarcoma
- Other:
- Osteochondritis Dissecans
- Sequestrum from osteomyelitis
- Neuropathic (Charcot) joint
- Tuberculoous Arthritis
- Inflammatory Arthropathy
Clinical Features
- History
- History of SOC is non specific
- Patients may be asymptomatic
- Slow, chronic progression of symptoms
- Pain and swelling
- Pain worse with activity
- Mechanical symptoms including stiffness, clicking, grating, locking
- Can occur in the bursa overlying an osteochondroma
- Physical Exam
- Decreased range of motion
- Can have warmth, erythema, or tenderness
- Joint effusion is often present
- Palpable masses can occur
Evaluation

Preoperative lateral radiograph showing a large intra-articular mass with cortical destruction and small, calcified nodules. Preoperative T2-weighted lateral MRI scan showing large intra-articular chondral nodules that have coalesced, consistent with tumefactive SOC.[7]

Gross pathology of the xray and MRI above[7]

Synovial Osteochondromatosis of the hand[10]

Synovial Osteochondromatosis of the knee[11]
Radiographs
- Recommended initial imaging modality
- Abnormal in 70% of cases[12]
- Findings[13]
- Multiple, smooth, oval-shaped calcified masses within the joint space or bursa
- Characteristic "pop corn appearance", typically evenly distributed
- Variable depending on stage of disease
- May show stippled calcification
- Serial imaging may show changes in size, disappearance, migration
- Degenerative changes, effusion are often seen
- Periarticular erosions are seen in 30% of cases due to pressure within a tight capsule[14]
MRI
- Early Findings
- Initially cartilage nodules are only visible on MRI
- Lobular appearance
- Cartilage bodies appear isointense on T1, hyperintense on T2
- Late Findings
- Signal drop out consistent with calcification
- Consider arthrogram
CT
- Useful early in disease process before calcification begins
- Can detect non-calcified masses, distinguish from simple joint effusion
- Low attenuation lesions with a lobular outline
- Calcifications[15]
- Optimal modality in assessing calcification
- Inferior to MRI for the following
- Does not show marrow invasion well
- Chondromal nodules can be occult
- Extent of disease better seen on MRI
Ultrasound
- Findings
- Heterogenous, avascular mass surrounded by fluid
- Nodules appear as hyperechoic foci with acoustic shadowing
- Dynamic evaluation can identify gravity-dependent nodules
Pathology
- Gross
- Glistening, gray-white polypoid cartilaginous or osteocartilaginous bodies
- Typically spherical
- Size ranges from millimeters to several centimeters
- Microscopic Synovium
- Villous hyperplasia, which imparts a wrinkled appearance on gross examination
- Cartilaginous bodies may be attached attached to the synovium
- Involvement may be focal or diffuse
- Cartilage can be hyaline or myxoid
Classification
- Primary
- Occurs in an otherwise normal joint
- Typically affects a single joint
- Common in 3rd to 5th decade of life
- Secondary
- Occurs in older patients with previous joint disease (i.e. osteoarthritis)
- Often bilateral with multiple joint involvement
Milgram Classification
- First presented in 1977[16]
- Based on gross and pathologic cases
- Not widely used for clinical decision making
- Stage I
- Disease: active, inflammatory intrasynovial process without loose bodies
- Symptoms: localized joint pain and swelling (or may be asymptomatic)
- Stage II
- Disease: active synovial proliferation with transitional loose bodies (transition from pedunculated to free)
- Symptoms: patients often present with mechanical symptoms and decreased range of motion
- Stage III
- Disease: characterized by the presence of multiple loose bodies, minimal synovial disease, minimal inflammation
- May be thought of as a quiescent stage of the disease with no ongoing metaplasia
Management
Nonoperative
- Indications
- Asymptomatic
- Mild symptoms not affecting range of motion
- Treatment
- NSAIDS
- Activity modification
- Cryotherapy
Operative
- Indications
- Severe symptoms affecting range of motion
- Mechanical symptoms
- Technique
- Open or arthroscopic
- Synovectomy, lose body resection
Rehab and Return to Play
Rehabilitation
- No clear rehabilitation guidelines
Return to Play/ Work
- No clear return to play guidelines
Complications and Prognosis
Prognosis
- Outcomes
- Treatment is mainly symptomatic, may help prevent degenerative changes
- Recurrence[17][18]
- 3-23%
- Thought to be due to incomplete surgical resection
Complications
- Malignant transformation into synovial chondrosarcoma
- Mechanical symptoms
- Clicking, grating or locking
See Also
- Internal
- External
- Sports Medicine Review Knee Pain: https://www.sportsmedreview.com/by-joint/knee/
References
- ↑ Jaffe HL (1958) Tumours and tumorous conditions of bones and joints, 1st edn. Lea & Fabiger, Philedelphia,USA, pp 558–567
- ↑ Felbel J, Gresser U, Lohmoller G, Zollner N (1992) Familial chondromatosis combined with dwarfism. Hum Genet 88:351–354
- ↑ Evans S, Boffano M, Chaudhry S, Jeys L, Grimer R. Synovial chondrosarcoma arising in synovial chondromatosis. Sarcoma. 2014;2014: 647939. Epub 2014 Mar 5.
- ↑ Adelani MA, Wupperman RM, Holt GE. Benign synovial disorders. J Am Acad Orthop Surg. 2008 May;16(5):268-75.
- ↑ Seckley J, Anderson SG, Snow TM, Benjamin M (2002) A rare case of polyarticular synovial osteochondromatosis. J Anat 200(5):524
- ↑ Image courtesy of https://orthoinfo.aaos.org/, "Synovial Chondromatosis"
- ↑ 7.0 7.1 7.2 Neumann, Julie A., et al. "Synovial chondromatosis." JBJS reviews 4.5 (2016).
- ↑ Robinson D, Hasharoni A, Evron Z, Segal M, Nevo Z (2000) Synovial chondromatosis: the possible role of FGF 9 and FGF receptor 3 in its pathology. Int J Exp Pathol 81:183–189
- ↑ Buddingh EP, Krallman P, Neff JR, NelsonM, Liu J, Bridge JA. Chromosome 6 abnormalities are recurrent in synovial chondromatosis. Cancer Genet Cytogenet. 2003 Jan 1;140(1): 18-22.
- ↑ Case courtesy of Dr Maulik S Patel, Radiopaedia.org, rID: 23031
- ↑ Terazaki, Carlos Renato Ticianelli, et al. "Synovial chondromatosis of the shoulder: imaging findings." Radiologia Brasileira 47 (2014): 38-42.
- ↑ Mohana-Borges AV, Chung CB, Resnick D (2004) Monoarticular arthritis. Radiol Clin North Am 42 (1):135–149
- ↑ Alexander JE, Holder JC, McConnell JR, Fontenot E Jr. Synovial osteochondromatosis. Am Fam Physician. 1987 Feb;35(2):157-61.
- ↑ Norman A, Steiner GC (1986) Bone erosion in synovial chondromatosis. Radiology 161:749–752
- ↑ Murphey MD, Vidal JA, Fanburg- Smith JD, Gajewski DA (2007) Imaging of Synovial Chondromatosis with Radiologic-Pathologic Correlation. RadioGraphics 27:1465–1488
- ↑ MilgramJW. Synovial osteochondromatosis: a histopathological study of thirty cases. JBone Joint Surg Am. 1977 Sep;59(6):792-801.
- ↑ Maurice H, Crone M, Watt I (1998) Synovial chondromatosis. J Bone Joint Surg Br 70:807–811
- ↑ Shpitzer T, Ganel A, Engelberg S (1990) Surgery for synovial chondromatosis: 26 cases followed up for 6 years. Acta Orthop Scand 61:567– 569
Created by:
John Kiel on 30 September 2022 14:42:45
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Last edited:
4 October 2022 15:52:15
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