Synovial Chondromatosis


Synovial chondromatosis is classified as either primary or secondary. Primary synovial chondromatosis is less common and occurs with no cause or known injury to the cartilage or synovium (1). A secondary synovial chondromatosis is more common and occurs in the setting of cartilage damage commonly found in osteoarthritis and osteochondritis dissecans (1). The chondromatosis occurs when a portion of cartilage becomes separated from the articular cartilage and then detaches and forms a loose body (1). Primary synovial chondromatosis is considered a benign neoplastic process based on histologic samples (1). It is not common for primary synovial chondromatosis to have a malignant transformation to chondrosarcoma (2). 

Example of synovial chondromatosis on xray (3)

Milgram has classified synovial chondromatosis into three phases (9). The first phase involves synovitis with no loose bodies, the second is loose bodies and synovitis, and the third phase is multiple loose bodies and no synovitis (9).

The knee joint is most commonly affected and then followed by hip, elbow, wrist, and ankle (1). The loose bodies can be found inside the joint capsule, but also in a bursa or tendon sheath (5).  Synovial chondromatosis is most commonly detected in male patients in their 30s to 50s (2).


Patients can present with a wide variety of symptoms with synovial chondromatosis. They may complain of nonspecific joint swelling, joint pain, and/or restriction in joint range of motion (5). In more severe cases, patients may complain of joint locking (5). Physical exam findings can include detection of an effusion, joint pain to palpation, crepitus in the joint, and a palpable nodule (5).

Standard radiographs can visualize the calcific densities seen in the third stage of synovial chondromatosis (9). The loose bodies are typically round and smooth (9). In earlier stages where calcifications cannot be seen, an MRI can help demonstrate synovitis and low signal loose bodies (1,9).

Standard radiograph showing multiple loose bodies (1)


Typical treatment for multiple loose bodies in the joint secondary to synovial chondromatosis is arthroscopic surgical removal (2). There is controversy regarding synovectomy to help prevent the recurrence of symptoms (5).

Surgical image of synovial chondromatosis (11)


Synovial chondromatosis can be classified as either primary or secondary. Malignant transformation into chondrosarcoma is rare (6). Patients with synovial chondromatosis can be treated with loose body removal and/or synovectomy. 

By Gregory Rubin, DO

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2)      Agaram, Narasimhan P., et al. “A Molecular Study of Synovial Chondromatosis.” Genes, Chromosomes & Cancer, vol. 59, no. 3, Mar. 2020, pp. 144–51. PubMed,

3)      Padhan, Prasanta, and Sakir Ahmed. “Synovial Chondromatosis.” The New England Journal of Medicine, vol. 381, no. 14, Oct. 2019, p. 1364. PubMed,

4)      Pinto, Ana Sofia, et al. “Synovial Chondromatosis of the Knee: Three Different Imaging Methods.” Rheumatology (Oxford, England), vol. 60, no. 12, Dec. 2021, p. 5832. PubMed,

5)      Wong, Sarah Hew-Ming, et al. “Synovial Chondromatosis of the Hand: Three Case Reports and Literature Review.” The Canadian Journal of Plastic Surgery = Journal Canadien De Chirurgie Plastique, vol. 11, no. 1, 2003, pp. 47–52. PubMed,

6)      Derek Stensby, J., et al. “Primary Synovial Chondromatosis of the Subtalar Joint: Case Report and Review of the Literature.” Skeletal Radiology, vol. 47, no. 3, Mar. 2018, pp. 391–96. PubMed,

7)      Marchie, Anthony, et al. “Efficacy of Hip Arthroscopy in the Management of Synovial Chondromatosis.” The American Journal of Sports Medicine, vol. 39 Suppl, July 2011, pp. 126S-31S. PubMed,

8)      Littrell, Laurel A., et al. “Imaging Features of Synovial Chondromatosis of the Spine: A Review of 28 Cases.” Skeletal Radiology, vol. 45, no. 1, Jan. 2016, pp. 63–71. PubMed,

9)      Ryan, Jay D., et al. “Synovial Chondromatosis Surrounding the First Metatarsophalangeal Joint: A Case Report.” Foot & Ankle Specialist, vol. 9, no. 2, Apr. 2016, pp. 174–78. PubMed,

10)   Dash, Kumar Kaushik, et al. “It’s Not What It Looks like: Challenges in Diagnosis of Synovial Lesions of the Knee Joint.” Journal of Experimental Orthopaedics, vol. 3, no. 1, Dec. 2016, p. 5. PubMed,


11)   George, Joseph, et al. “Synovial Chondromatosis Ankle – A Case Report.” Journal of Orthopaedic Case Reports, vol. 13, no. 4, Apr. 2023, pp. 21–24. PubMed,