Synovial Chondromatosis


Synovial chondromatosis kneeKnee Chondromatosis




Chondroid metaplasia of synovium affecting large joints

- form nodules of hyaline cartilage

- break free into joint


Synovial osteochondromatosis

- lesions can mineralize or ossify




Malignant transformation


Rare case reports of transformation to chondrosarcoma


Evans et al Sarcoma 2014

- 78 cases of synovial chondromatosis

- 5 (6%) incidence of transformation to chondrosarcoma




Rare lesion

Most common in 20's and 30's

Male:Femal 4:1






Marked predilection for large joints

- knee 70%

- hip 20%

- shoulder > elbow > ankle > wrist


Any synovial lined joint, tendon or bursal cavity






Mesenchymal cells in joint capsule (subsynovial layer) become chondroblasts instead of fibroblasts

- form nests of cartilage

- nests grow & protrude into joint

- covered by synovium

- eventually become pedunculated and connected by synovial stalk


Break off and lie free in joint as cartilaginous loose bodies

- continue to grow in joint secondary to synovial diffusion


Can undergo secondary calcification and ossify




Older patient with chondral injury (OA / RA / AVN / Charcot / TB)

- cartilage fragments can seed synovium and continue to grow


Patella Chondral DamageSecondary ChondromatosisSecondary Synovial Chondromatosis




Central necrotic area that may be calcified

- peripheral ring of viable chondrocytes 

- disorganized chondrocytes with cellular atypia

- can be difficult to pick from chondrosarcoma




Phase 1 / Early: Synovitis, no loose bodies

Phase 2 / Transitional: Synovitis & loose bodies

Phase 3 / Late: Loose bodies, no synovitis




Pain & swelling

Loss of ROM

Locking symptoms secondary to loose bodies




Demonstrate calcified lesions / synovial osteochondromatosis


Knee syn osteo xrayKnee syn osteo xray


Ankle xray synovial osteochondrondromatosisSyn oc ankle xray 2

Wrist syn oc xrayWrist syn oc xray



Synovial Proliferation


Soft tissue lesions same signal intensity as cartilage


Synovial Chondromatosis MRI KneeMRI Knee Synovial Chondromatosis


Synovial chondro knee 1Syn chondro 2

Synovial chondromatosis


Syn osteo 1synovial osteo 2syn osteo 3

Synovial osteochondromatosis




Demonstrate osseous / calcified bodies


OC CT knee 1OC CT knee 2




Synovial proliferation

- localised or generalised

- can see cartilage growing from synovium


Multiple loose bodies +++


Knee ChondromatosisKnee Chondromatosis


Knee ChondromatosisKnee Chondromatosis


Synovial osteochondromatosis






Early surgery to prevent secondary degeneration






Vumedi arthroscopy synovial chondromatosis


Surgical technique PDF synovial chondromatosis


Results arthroscopy


Ogilvie-Harris et al Arthroscopy 1994

- 13 patients with generalised disease

- 5 treated with removal loose bodies only: 3/5 recurrences

- 8 with synovectomy: 0/8 recurrences


Results TKA


Houdek et al J Arthroplasty 2017

- 20 patients with synovial chondromatosis undergoing TKA
- 5/20 (25%) had a recurrence: 2 observation, 2 revision TKA, 1 amputation due to chondrosarcoma

- 3/20 (15%) revision TKA for stiffnessness







Open surgical hip dislocation


Arthroscopic technique


Arthroscopic technique PDF hip synovectomy


Vumedi hip arthroscopy synovial chondromatosis


Results arthroscopic synovectomy


Boyer et al JBJS Br 2008

- arthroscopic debridement in 111 patients, follow up average 6 years

- 57% good or excellent outcome

- 20% required subsequent repeat arthroscopy

- 38% required subsequent open synovectomy

- 20% went on to require THA


De Sa et al Arthroscopy 2014

- systematic review of arthroscopic hip debridement

- 14 studies and 197 patients

- 7.1% recurrence rate

- minor complication rate 1%


Results THA


Tibbo et al J Arthroplasty 2018

- 26 patients with synovial chondromatosis THA

- recurrence in 3/26 at mean of 1 year

- 10 year survival 82%

- 15 year survival 64%






Liu et al Clin Orthop Surg 2023

- 28 shoulders with synovial chondromatosis

- involving glenohumeral joint / subacromial space / biceps sheath

- 36% rotator cuff tears

- 7% shoulder OA

- recurrence 3/22 (14%)


Park et al Should Elbow 2022

- systematic review of 27 articles and 48 patients

- arthroscopic treatment successful in 71%

- treatment failure associated with bicipital tendon sheath involvement

- recurrence rate 15%




Surgical technique PDF


Bojanic et al Foot Ankle Int 2021

- 17 patients

- 14/17 had anterior and posterior compartment involvement

- 2/17 dissatisfied

- no recurrence