SYNOVIAL CHONDROMATOSIS

Synovial chondromatosis is a rare condition characterized by benign, proliferative cartilaginous lesions that arise from the synovial tissue, tenosynovium, or bursal lining of/or near joints. Although synovial chondromatosis can be found all over the body, the condition most commonly affects large joints like the knees, elbows, ankles, hips, and shoulders. However, it also may involve the wrist, metacarpophalangeal (MP), or interphalangeal (IP) joints. The condition is also usually monoarticular, but more than one joint may be affected in some cases. Patients that only present with mild symptoms may be effectively managed with careful observation and some conservative interventions, but resection of loose bodies with or without synovectomy is generally typically needed for cases of primary synovial chondromatosis with debilitating symptoms.^1-5

Pathophysiology

• Primary synovial chondromatosis was believed to result from a benign reactive metaplasia of synovial tissue into cartilaginous tissue, arising either from the articular synovium or the tendon sheath synovium; however, increasing evidence has suggested that it may actually be a neoplastic condition.^1,3
  • There are reports of its malignant transformation into chondrosarcoma and evidence of involved chondrocytes, demonstrating atypical cytology and architecture on histology.¹
  • Multiple cytogenetic abnormalities have also been reported, such as 1p13, 1p21–22, 12q13–15, and +5, and a murine model with a hedgehog signaling mutation has shown an increased incidence of synovial chondromatosis.¹
  • Synovial chondromatosis commonly progresses gradually, although spontaneous regression also has been reported.¹
• A commonly used classification system was created by Milgram and categorizes it into the following 3 phases:
  • Early phase: no loose bodies are present, but active intrasynovial disease exists
  • Transitional phase: loose bodies are present with active intrasynovial disease
  • Late phase: multiple loose bodies are present without active intrasynovial disease^3,4
  • Synovial chondromatosis can be further subdivided into either primary or secondary, and either synovial or tenosynovial:
    • Primary: cartilaginous tissue arising directly from metaplastic synovial tissue, tenosynovium, or bursal lining
    • Secondary: loose bodies arising from hyaline cartilage implanted into the joint space or tendon sheath from degenerative joint disease, trauma, or neuropathic arthropathy
    • Synovial (intra-articular) chondromatosis: more common and usually monoarticular, unless associated with a familial chondromatosis or conditions such as Wagner-Stickler syndrome
    • Tenosynovial (extra-articular) chondromatosis: most common over the flexor tendons in the fingers but can be found along any tendinous sheath¹

Related Anatomy

• MP joint
• IP joint
• Radiolunar joint
• Synovial tissue
• Cartilaginous tissue
• Tenosynovium
• Bursa
• Tendon sheath

Incidence and Related Conditions

• The exact incidence of synovial chondromatosis is ill-defined and probably less than currently estimated, likely due to confusion with the much more prevalent secondary chondromatosis or soft tissue chondroma.¹
• Synovial chondromatosis can occur at any age, but usually presents between ages 20-50 years.^1,6
• No sex predilection has been established, but some studies suggest that it is twice as common in men versus women.^1,3,6  
• Malignant transformation of synovial chondromatosis into chondrosarcoma was considered extremely rare, but one study reported a 5% relative risk. The reported recurrence rate for synovial chondromatosis also varies widely, with reports ranging from 3-60%.¹
• The most common site of synovial chondromatosis is the large joints, predominantly the knee (~40%), hip, and shoulder.⁴ 
  • It rarely affects the wrist, MP, and IP joints, with very few cases reported. Tenosynovial chondromatosis, however, is most often found in the flexor tendons of the hand.^1,3,7

Differential Diagnosis

• Secondary chondromatosis
• Chondrosarcoma
• Soft tissue chondroma
• Periosteal chondroma
• Tenosynovial giant cell tumor
• Calcifying aponeurotic fibroma
• Tumoral calcinosis
• Hydroxyapatite deposition disease
• Foreign body
• Inflammatory arthritides
• Osteoarthritis
• Osteochondritis dissecans
• Osteochondral fracture
• Neuropathic joint
• Tuberculosis
• Rheumatoid arthritis
• Monoarticular synovitis
• Synovial sarcoma
• Villonodular synovitis
• Hemangioma
• Dermatomyositis
• Hyperparathyroidism

A typical patient is a 33-year-old, right-handed man presenting with pain and swelling in the MP joint of his right index finger. The pain had been gradually increasing in severity during the past 2 years. More recently, he began noticing crepitus and loss of motion that was limiting his fine motor skills and grip strength. With this progression of symptoms, the man arranged for a medical consultation to investigate his condition.

• Infection
• Osteoarthritis
• Recurrence
• Chondrosarcoma

• Synovectomy and removal of loose bodies are effective for relieving pain and swelling in the majority of synovial chondromatosis cases.³
• In one study of 31 patients with synovial chondromatosis, 12 had a loose body removal with synovectomy, 16 had loose body removal only, and 3 had more radical surgery.
  • Based on results from 26 evaluable patients, it was concluded that outcomes were no different with or without synovectomy.¹⁰
• Other studies have also shown that synovectomy in conjunction with loose body removal was helpful for preventing recurrence.⁹

• Much is still unclear about synovial chondromatosis, including its exact incidence, sex predilection, and chance of recurrence, but it’s important to recognize it as a rare condition in the upper extremity that can easily be misdiagnosed due to its wide range of nonspecific symptoms.¹
• Due to its assumedly low frequency in joints of the hand, it is likely that synovial chondromatosis is often treated under the clinical pretense of another pathology. If refined, ultrasound may help to produce a more reliable diagnosis, but until then, surgeons should include it as a differential diagnosis in patients with pain and stiffness of their fingers.⁸
• Although it has been reported that the risk of malignant change is up to 5%, distinguishing between synovial chondromatosis and its progression to low-grade chondrosarcoma is histologically difficult.²
• Tenosynovial and intra-articular synovial chondromatosis are histologically the same entity, but it’s important to differentiate between them for surgical planning and because of the reportedly higher recurrence rate in tenosynovial chondromatosis. Unfortunately, the nomenclature is often unclear in the literature, and the term synovial chondromatosis often encompasses tenosynovial chondromatosis as well.¹
• Tumors near joints generally involve one side or the other of the joint.  At the elbow, for example, a tumor is usally in the humerus, ulna or radius but not in more than one of the bones of the joint.  Synovial chondromatosis is one of the few lesions that routinely involves both sides of the joints. The wrist case shown here shows an example of this phenomenon.¹¹

Cited

1. Ho YY, Choueka J. Synovial chondromatosis of the upper extremity. J Hand Surg Am 2013;38(4):804-10. PMID: 23474166
2. Sano K, Hashimoto T, Kimura K, Ozeki S. Articular synovial chondromatosis of the finger. J Plast Surg Hand Surg 2014;48(5):347-9. PMID: 23596991
3. Tominaga A, Takenaka S, Murase T, et al. Synovial chondromatosis of the metacarpophalangeal joint: a case report and literature review. Hand Surg 2012;17(3):395-8. PMID: 23061954
4. Reverté Vinaixa MM, Singh R, Monyart JM, et al. Wrist synovial chondromatosis: case report and literature review. Hand Surg 2012;17(2):233-8. PMID: 22745090
5. Ballet FL, Watson HK, Ryu J. Synovial chondromatosis of the distal radioulnar joint. J Hand Surg Am 1984;9(4):590-2. PMID: 6747249
6. Maurice H, Crone M, Watt I. Synovial chondromatosis. J Bone Joint Surg Br 1988;70(5):807-11. PMID: 3192585
7. Rogachefsky RA, Zlatkin MB, Greene TL. Synovial chondromatosis of the distal radioulnar joint: a case report. J Hand Surg Am 1997;22(6):1093-7. PMID: 9471084
8. Spiers JD, Wijeratna MD, Jones JW. Synovial chondromatosis affecting a digital proximal interphalangeal joint. Hand Surg 2014;19(1):127-9. PMID: 24641756
9. Neumann JA, Garrigues GE, Brigman BE, Eward WC. Synovial Chondromatosis. JBJS Rev 2016;4(5). PMID: 27490219
10. Shpitzer T, Ganel A, Engelberg S. Surgery for synovial chondromatosis. 26 cases followed up for 6 years. Acta Orthop Scand 1990;61(6):567-9. PMID: 2281768  
11. Slesarenko YA, Hurst LC, Dagum AB. Synovial chondromatosis of the distal radioulnar joint. Hand Surg 2004; 9(2): 241-243.

New Articles

1. Sakamoto A, Naka T, Shiba E, et al. Extra-Articular Tenosynovial Chondromatosis of the Finger: A Case Series Study of Three Cases, One Including Excessive Osseous Invasion. Open Orthop J. 2017;11:417-423. PMID: 28603573
2. Neumann JA, Garrigues GE, Brigman BE, Eward WC. Synovial Chondromatosis. JBJS Rev 2016;4(5). PMID: 27490219

Reviews

1. Chen YX, Lu YX, Zhuang ZE, Li ZY. Extra-articular tenosynovial chondromatosis of the left ring finger in a 23-year-old man: A case report and literature review. Exp Ther Med 2015;10(4):1581-1583. PMID: 26622530
2. Kumar A, Thomas AP. Recurrent synovial chondromatosis of the index finger--case report and literature review. Hand Surg 2000 Dec;5(2):181-3. PMID: 11301515

Classics

1. Constant E, Harebottle NH, Davis DG. Synovial chondromatosis of the hand. Case report. Plast Reconstr Surg 1974;54(3):353-8. PMID: 4854562
2. Curr JF. Synovial osteochondromatosis; two uncommon examples. Br Med J 1949;2(4635):1020-2. PMID: 15393039