Arthroscopic synovectomy with loose bodies removal in a case of synovial chondromatosis of knee joint

INTRODUCTION

Synovial osteochondromatosis (SOC) presents clinically with symptoms that closely mirror traditional joint arthropathies such as osteoarthritis in their temporal course but differ in their histopathology and clinical progression.¹ Synovial chondromatosis is a rare condition that affects synovial joints, tendon sheaths or bursa. It usually affects mono-articular and it occurs bilaterally 10% of the time.² Is most commonly seen in patients between the third and the fifth decades of life and the prevalence in men is up to three times greater than in women.³ The most commonly involved joint is the knee followed by, in descending order of frequency, hip, shoulder, elbow, ankle and wrist.⁴ Histologically, synovial cells undergo metaplasia into chondrocytes, which transform into multiple cartilage nodules.⁵ The treatment of choice for symptomatic patients is surgical intervention.

CASE REPORT

A 45-years-old man came to the outpatient clinic with a history of severe pain in his right knee that was associated with functional incapacity and limitation of movement for the past 6 months. There is no history of trauma or loss of weight/appetite. Upon examination, the swelling was found in the joint, with a range of movement limited terminally and associated with severe pain and negative joint puncture. From a routine radiological evaluation of the knee in AP view, no abnormalities were seen.

The patient then underwent a magnetic resonance examination, which showed a large accumulation of fluid inside the joint, associated with marked synovial proliferation and associated multiple cartilaginous nodules, The patient underwent an arthroscopy on the right knee, which revealed numerous whitish irregular fragments, with the removal of the lesion and near total synovectomy with removal of loose bodies with debridement of the joint (Figure 3).

The material was sent for pathological examination, which showed the presence of synovial chondromatosis. Eight months after the surgery, the patient is in good general condition, without complaints, with a range of motion of 130° in the left knee without joint effusion or signs of inflammation.

DISCUSSION

Primary synovial chondromatosis of the knee joint is a rare disease. It’s true incidence is unknown. Although primary synovial chondromatosis is a locally aggressive condition with a slight tendency to recur, it has no metastatic potential. The treatment for symptomatic primary synovial chondromatosis consists of the removal of the cartilaginous bodies with or without partial synovectomy.^6,7 Conventional radiology is mostly characteristic if the free bodies are calcified (osteochondromatosis), but are difficult to interpret when they are radiotransparent (chondromatosis). T2-weighted magnetic resonance image shows heterogenous synovial hyperplasia and ring-shaped images with a center showing greater intensity.

On arthroscopy, there is a marked thickening of synovium seen and associated with multiple small and loose cartilaginous bodies. Loose bodies removal can be performed using additional necessary portals. The differential diagnosis of the lesion is usually synovial chondrosarcoma which occurs when small fragments of bone or joint cartilage detach and remain in the joint space following trauma or degenerative diseases. Authors believe that the proposed treatment was appropriate since extensive synovectomy presents a greater likelihood of functional limitation.⁷

Complications of synovial chondromatosis can be secondary osteoarthritis, malignant transformation and recurrence.^8,9 Pigmented villonodular synovitis, synovial hemangioma and lipoma arborescens are a few conditions that can mimic synovial chondromatosis.¹⁰ Radiography and histology may help in accurately differentiating between them.

CONCLUSION

Patient with synovial chondromatosis needs long-term follow-up to look for any recurrence or malignant change. Extensive synovectomy with removal of all loose bodies using necessary portals is essential. The use of additional accessory portals helps in the removal of cartilaginous loose bodies.

Funding: No funding sources

Conflict of interest: None declared

Ethical approval: Not required

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