Haemosiderotic Synovitis Secondary to Anticoagulant Use: An Unusual Mechanism of Failure of a Unicompartmental Knee Replacement

Abstract

Haemosiderotic synovitis is a rare condition caused by recurrent or chronic haemarthroses. This may lead to intra-articular destruction, a painful joint, and, if untreated, ankylosis of the joint. We highlight a case of an elderly lady who presented to an orthopaedic clinic with left knee pain, following recurrent left knee atraumatic haemarthroses secondary to oral anticoagulant use. At her presentation, she had a left medial unicompartmental knee prosthesis in situ. Weight bearing radiographs of the left knee showed marked loss of lateral joint space with valgus alignment. These radiographic findings were not present on the radiographs taken at her first presentation with haemarthrosis nine months previously. A left revision total knee arthroplasty was performed, and a diagnosis of haemosiderotic synovitis was made following histological analysis of intraoperative tissue samples. This case highlights an unusual mechanism of failure of a unicompartmental knee replacement. Though haemosiderotic synovitis is an exceedingly rare condition, it must be considered following recurrent haemarthrosis as, due to its destructive nature, prompt recognition and treatment is paramount.

Figure 1

Long-leg radiographs demonstrating bilateral medial unicompartmental knee replacements. Valgus deformity of the left knee with loss of lateral joint space.

Figure 2

Weight-bearing AP radiograph of the left knee. Medial unicompartmental knee replacement in situ. Loss of lateral joint space, subchondral sclerosis, and infarction of the lateral femoral condyle.

Figure 3

Weight-bearing AP radiograph of the left knee from nine months prior to presentation. Medial unicompartmental knee replacement in situ.

Figure 4

Clinical photo of the left knee with a lateral parapatellar exposure. Medial unicompartmental knee replacement in situ. Haemosiderin staining of the lateral femoral condyle.

Figure 5

Postoperative AP radiograph of the left knee. Revision left total knee in situ. Pin holes used for navigation are present distal to the stemmed tibial component.

Figure 6

Postoperative lateral radiograph of the left knee. Revision left total knee in situ. Pin holes used for navigation are present distal to the stemmed tibial component.

Figure 7

Long-leg radiographs demonstrating a medial unicompartmental knee replacement and revision left total knee replacement at six months.