SYNOVIAL CHONDROMATOSIS

DR Q M MORSHED MAHBUB ABIR

MS RESIDENT

NITOR

INTRODUCTION:

• Synovial chondromatosis is a rare condition in which foci of cartilage develop in the synovial membrane as a result of benign metaplasia of the subsynovial connective tissue.

• Countless tiny fronds of synovial membrane undergo cartilage metaplasia at their tips; these tips break free and may ossify.

• Self-limited and non-aggressive.

• Also known as primary synovial osteochondromatosis, synovial chondrometaplasia and Reichel syndrome.

INCIDENCE AND DEMOGRAPHICS:

• Exact prevalence is unknown.

• Male-to-female ratio of 2:1.

• Patients are usually aged 20-40 years.

ETIOLOGY

• Primary synovial chondromatosis

• Etiology unknown.

• Secondary synovial chondromatosis

• more common.

• Free chondral or osteochondral fragments formed by underlying disease implant into the synovium and induce metaplastic cartilage around them.

• Occurs in preexistent osteoarthritis, , rheumatoid arthritis, osteonecrosis, infection or trauma.

PATHOPHYSIOLOGY

• Benign process associated with an extremely low risk of malignancy.

• Typically monoarticular, with the large joints such as the knee joint is involved in 60-70% of cases; the shoulder, elbow, and hip are the next most frequently involved joints

• Growth factors BMP-2 and BMP-4 may promote cartilaginous and osteogenic metaplasia.

PRESENTATION:

• Gradual onset of monoarticular pain and stiffness, decreased range of motion, effusions, crepitation and eventual locking of the joint.

• Secondary synovial chondromatosis may be present after long standing osteoarthritis, trauma or infection.

EXAMINATION

• LOOK the joint may be enlarged with no overlying skin changes.

• FEEL large effusion with spongy sensation, palpable loose bodies in synovial recesses, tenderness along joint line.

• MOVE ROM is typically decreased and movement is painful. Ligamentous examination (eg, Lachman test, drawer test) are normal.

INVESTIGATIONS

• CBC, ESR and C-reactive protein level if the physical findings suggest possible infection.

• Results are expected to be normal in primary synovial chondromatosis, but may be elevated in secondary synovial chondromatosis due to systemic inflammation.

X-RAY APPEARANCE

• Frequently normal. Between 5-30% of patients do not have radiographicallyvisible calcifications although secondary widening of the joint space may be noted.

• If loose bodies undergo ossification, they may be visible in the joint space. The pattern of mineralization varies with size.

• In secondary synovial chondromatosis, changes consistent with the underlying disease process are evident.

Radiograph of the knee with synovial chondromatosis. No abnormality noted.

Radiograph of the knee with synovial chondromatosis. Visible calcification in joint space

MAGNETIC RESONANCE IMAGING

• Cartilaginous nodules have intermediate signal intensity on T1-weighted images and high signal intensity on T2-weighted images.

• The addition of intra-articular gadolinium-based contrast material increases the sensitivity for detecting lesions.

Synovial osteochondromatosis shown on MRI. A, Oblique axial proton density MR image of the ankle shows multiple, fairly uniformly sized bodies (arrow) with low signal rims and intermediate signal centers.

B, Corresponding T2-weighted image shows the periphery of the nodules to remain dark, consistent with calcification or bone, and the centers of the nodules to remain intermediate in signal intensity. The joint fluid is very bright on the T2-weighted image. C, calcaneus; T, talus.

DIAGNOSTIC PROCEDURES

• Arthrocentesis is used to obtain a sample of synovial fluid if the physical findings suggest infection. The sample is sent for a cell count, crystal examination, Gram staining, and cultures. All findings should be within normal limits in primary synovial chondromatosis.

TREATMENTMEDICAL THERAPY

• NSAIDs can be used along with transcutaneous therapies (eg, ultrasound, thermal therapies) for reduction of inflammation. Patients do not benefit significantly from nonoperative therapy.

SURGICAL THERAPY

• The traditional surgical approach consisted of an open arthrotomy of the joint, with removal of all loose bodies and either a partial or a full synovectomy - largely been abandoned now.

• Standard treatment is arthroscopic examination and excision of loose bodies, with limited synovectomy of involved synovium only.

ARTHROSCOPIC TREATMENT PROCEDURE

• The affected leg is surgically prepared to the level of the tourniquet.

• Standard arthroscopic portals made in the medial suprapatellarand medial and lateral parapatellar locations

• A 30° arthroscope is inserted through the lateral parapatellarportal, and diagnostic arthroscopy is performed. Abundant round cartilaginous bodies, both free in the joint and embedded in the synovial lining are typically present.

• Arthroscopic graspers are used to remove all free loose bodies.

• Large or pedunculated lesions embedded in the synovium are excised by using arthroscopic graspers and shavers. A large outflow cannula is used for extracting loose cartilaginous pieces.

• Specimens are sent to for histo-pathology.

• Arthroscopic instruments are withdrawn, and portals are closed, sterile dressing is applied and the knee is immobilized.

Arthroscopic appearance of synovial

chondromatosis loose bodies in the

shoulder.

Arthroscopic shaver during attempted

removal of loose bodies.

Arthroscopic image of pedunculated

synovial chondromatosis in the knee.

POSTOPERATIVE CARE

• The patient is discharged with pain medication, deep venous thrombosis prophylaxis.

• Pathology results are carefully followed up.

• Immediate, full weight bearing is permitted in a knee immobilizer, with instructions to elevate and apply ice to the knee for the first 3-7 days.

FOLLOW-UP

• Follow-up visit 3-7 days after surgery for evaluation of surgical wounds. Sutures are removed and sterile bandages are applied.

• Physical therapy for full active, active-assisted, and passive range of motion begins. Full return to activity can be anticipated by 6-8 weeks after surgery.

COMPLICATIONS

• Stiffness and recurrence of mechanical symptoms due to loose-body generation are most common.

• Repeat arthroscopic surgery were needed in < 20%.

OUTCOME AND PROGNOSIS

• In current practice, most authors agree that arthroscopic removal of loose bodies for mechanical symptoms is the best surgical treatment. This strategy minimizes postoperative stiffness associated with open procedures and successfully accomplishes synovectomy and loose body removal.

REFERENCE• Apley’s System of Orthopaedics and Fractures, 9th Edition

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