921 - Loose Bodies, Stiff Knees: A case of Synovial Osteochondromatosis

Thursday, February 19, 2026

5:00 PM - 6:30 PM AST

Presenting Author(s)

AA

Aruba Asad, DO

PM&R Resident
Nassau University Medical Center
Huntington Station, New York, United States

Co-Author(s)

MF

Michael Fedorovsky, DO

PM&R Resident
Nassau University Medical Center
East Rockaway, New York, United States
NT

Naveed Tariq, DO

PM&R Resident
Nassau University Medical Center
East Hempstead, New York, United States
AZ

Aaron Zell, DO

PM&R PGY-2
Nassau University Medical Center
Copiague, New York, United States
WG

Walter Gaudino, MD

Attending physician
Nassau University Medical Center
East Meadow, New York, United States

Submitter(s)

AA

Aruba Asad, DO

Nassau University Medical Center
huntington Station, New York, United States

Case Diagnosis: Synovial osteochondromatosis

Case Description: The patient is a 74-year-old female with history of bilateral knee osteoarthritis and osteopenia. She was evaluated for right knee pain that worsens in the morning and with sit-to-stand transitions but improves with sitting or walking. The patient exhibited an antalgic gait, favoring the left leg. The right knee showed mild swelling, diffuse tenderness, and palpable bony growths. Range of motion was preserved but accompanied by noticeable crepitus. X-rays revealed findings suggestive of synovial osteochondromatosis (SOC).

Discussions: Synovial osteochondromatosis is a rare, benign joint disorder characterized by the formation of cartilage-capped nodules within the synovium, which may detach and form intra-articular loose bodies, often occurring in middle-aged males. It can mimic degenerative joint disease by causing pain, stiffness, and mechanical symptoms such as crepitus or locking sensation. SOC arises from synovial metaplasia, producing nodules that calcify over time. Radiographs in this case revealed multiple calcified intra-articular bodies in the right knee, consistent with SOC, alongside mild degenerative changes from osteoarthritis. While SOC typically presents earlier in life, diagnosis may be delayed until later, as was the case with this patient. Management ranges from conservative approaches such as physical therapy and NSAIDs to surgical excision of loose bodies when symptoms persist; however, recurrence remains a risk if the synovium is not fully addressed.

Conclusions: This case illustrates chronic right knee pain exacerbated by synovial osteochondromatosis in an older patient with coexisting osteoarthritis. Conservative strategies have provided limited relief, but given her preference, another trial of nonoperative care is reasonable. If symptoms persist, surgical options may be considered. In rare cases, malignant transformation to chondrosarcoma may occur, particularly in long standing or multiple osteochondromas. Regular follow-up is essential to monitor for progression, recurrence of intra-articular bodies, or degenerative changes that could further impair joint function.