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CASE REPORTS
PRIMARY ANKLE SYNOVIAL CHONDROMATOSIS
ANISH P KADAKIA*, SUSHIL K SABNIS**, NIRANJAN R RATHOD***
INTRODUCTION S
ynovial chondromatosis of the ankle is unusual. It is a benign process and presents as a juxta-articular mass. The clinical picture is suggestive of chronic arthritis. The radiological picture is more or less diagnostic of the pathology. Simple excision of the loose bodies with or without synovectomy is the treatment.
CASE REPORT
A 35-year-old male patient came with history of pain and swelling in the right ankle of one and half year duration. Pain was dull aching and present throughout the day. On examination, there was swelling of the right ankle, more anteriorly, with palpable loose bodies. There was associated terminal restriction of motion.
There was no sign of infection or inflammation. There was no history of trauma, fever or constitutional symptoms. There was no other joint involvement. Blood investigations were within normal limits. Plain radiograph of the right ankle showed multiple radio-opaque loose bodies in the joint anteriorly (Fig. 1). Magnetic Resonance Imaging (MRI) of the right ankle showed multiple loose bodies (Fig. 2) in the joint cavity anterolaterally and near the inferior tibio-fibular syndesmosis. The loose bodies were excised using an anterior ankle approach (Fig. 3). The joint cavity and the articular cartilage were inspected. There was no synovial disease. Histopathological analysis of the excised loose bodies was consistent with clinical diagnosis of synovial chondromatosis. Patients’ postoperative recovery was uneventful and there was no recurrence at three-year follow-up.
DISCUSSION
Synovial osteochondromatosis is typically a benign process involving metaplasia of the synovial
Fig. 1 : Plain radiograph of the right ankle lateral view showing the loose bodies anteriorly.
initima (of joints, bursae or tendon sheaths) and the formation of cartilaginous nodules that may eventually become ossified. The loose bodies derive nourishment from the synovial fluid and grow in size. Alternatively, synovial osteochondromatosis may degenerate to or be associated with a malignant process.1 It is of two types : familial (myriad very small densities, presents early in life) and nonfamilial (several small-large densities, presents later in life). It usually affects large joints and involvement of the ankle is rare.
The pathogenesis is divided into three recognizable
Fig. 2 : MR image of the right ankle.
phases: 1) active intrasynovial disease only, with no loose bodies; 2) transitional lesions with both active intrasynovial proliferation and free loose bodies; and 3) multiple free osteochondral bodies with no demonstrable intrasynovial disease.2 It typically presents in a single joint and is a chronically progressive condition without any tendency to resolve spontaneously eventually leading to joint deterioration and secondary osteoarthritis.3 Chronic articular pain is the main symptom, followed by swelling, limitation in motion range, free palpable bodies. Radiographs should be obtained first. Plain radiographs usually clinch the diagnosis. MRI should then be obtained preoperatively to demonstrate the true extent of the disease. It may be confused with pigmented villonodular synovitis (PVNS) if MRI images alone are available, and plain films may help resolve such a difficulty if it arises. Until the loose bodies are ossified or calcified they may be radiographically invisible. This often leads to an unfortunate delay in treatment. The characteristic MRI findings are : target appearance of some loose bodies with a low intensity peripheral rim and a center isointense to the soft tissues on T1-weighted images, with loss of signal of T2-weighted images.4 The distinguishing feature of synovial chondromatosis is calcification, which appears as signal voids within the synovium and is visualized optimally when intra-articular fragments are calcified.
Fig. 3 : Multiple pearly-white loose bodies.
The differential diagnosis of primary synovial chondromatosis includes secondary reactive synovial chondromatosis and synovial chondrosarcoma.5 In the secondary form, the initial predisposing factor is an unrelated articular process leading to joint disintegration, production of intraarticular fragments, synovitis and eventually, to synovial metaplasia. The cause of the primary or idiopathic one is unknown. If gross examination at the time of surgery shows that the disease is in the third phase, it would appear that synovectomy may not be necessary. However, extrasynovial intra-articular cartilaginous lesions may persist after synovectomy in the other two phases and may grow, causing recurrence of clinical symptoms in the absence of new intrasynovial disease.2 Arthroscopic management offers the following advantages over open synovectomy: a more thorough evaluation of the joint and synovium, better access for surgical synovectomy, and decreased postoperative morbidity.6 Synovial chondromatosis must be considered in the differential diagnosis of chronic articular pain and monoarthritis.7
REFERENCES
1. Valmassy R, Ferguson H. Synovial osteochondromatosis. A brief review. J Am Pediatr Med Assoc 1992; 82 : 427-31.
2. Milgram JW. Synovial osteochondromatosis : a histopathological study of thirty cases. J Bone Joint Surg
1977; 59A : 792-801.
3. Sekosky M, Lefkowitz H, Steiner I. Osteochondromatosis of the ankle. J Foot Surg 1990; 29 : 330-33.
4. Blandino A, Salvi L, Chirico G, et al. Synovial osteochondromatosis of the ankle : MR findings. Clin Imaging 1992; 16 : 34-6.
5. Holm CL. Primary synovial chondromatosis of the ankle. A case report. J Bone Joint Surg 1976; 58a : 878-80.
6. Bynum CK, Tasto J. Arthroscopic treatment of synovial disorders in the shoulder, elbow, and ankle. Am J Knee Surg 2002; 15 : 57-59.
7. Aguilera S, Pizzi T, Donoso I. Synovial chondromatosis : review of 25 monoarticular cases. Rev Med Chil 1995; 123 : 1257-62.
