Pediatric Synovial Osteochondromatosis of the Knee with Leg Length Discrepancy: A Case Report

Abstract

Introduction: Synovial chondromatosis (SC) is very rare among children. We are aware of no reports of patients with SC accompanied by leg length discrepancy (LLD).

Case report: We describe a case of synovial osteochondromatosis of a 7-year-old boy complicated by LLD. We performed epiphysiodesis of the distal femur and arthroscopic resection of loose bodies and total synovectomy. Three years after surgery, LLD had been corrected and there was no sign of recurrence.

Conclusion: Physicians should be aware of synovial osteochondromatosis complicated by LLD in childhood and take radiographs of the whole length of lower legs when this condition is suspected.

Keywords: Synovial osteochondromatosis; child; knee joint; leg length discrepancy.

Figure 1

Plain radiographs. Some calcific loose bodies are visible in the lateral anterior knee joint (arrow). (a) Anteroposterior view and (b) lateral view.

Figure 2

Magnetic resonance imaging (MRI). MRI reveals many loose bodies that signaled low in T1-weighted and T2-weighted images. (a) T1-weighted sagittal view and (b) T2-weighted sagittal view.

Figure 3

Computed tomography (CT) scan. CT shows numerous loose bodies in the knee joint. (a) Sagittal view and (b) three-dimensional-CT (3D-CT).

Figure 4

Full-leg radiograph. Full-leg radiograph demonstrated a leg length discrepancy of 2.2 cm (right: 68.7 cm, left: 66.5 cm).

Figure 5

Microscopic image. (Hematoxylin-eosin staining) Pathological analysis shows multiple nodules consisting of hyaline cartilage surrounded by synovial tissues.

Figure 6

Full-leg radiograph at final follow-up. Leg length discrepancy had been largely eliminated 6 months after removal of the eight plates. There is no apparent sign of recurrence.