Subchondral bone cyst of the apical portion of the proximal sesamoid bone as a cause of severe lameness in aWarmblood filly

Abstract

A 20-month-old Warmblood filly was evaluated for acute onset of a nonweightbearing lameness and swelling of the left hindlimb. Clinical and lameness evaluation and diagnostic intrasynovial anaesthesia isolated the lameness to the left hind metatarsophalangeal region. Radiography and ultrasonography revealed a subchondral cystic lesion of the apical portion of the lateral proximal sesamoid bone associated with oedema and synovial effusion of the metatarsophalangeal joint. Arthroscopic surgical debridement of the subchondral cystic lesion resulted in immediate post operative improvement in the lameness score. Rest and controlled exercise achieved complete resolution of the lameness with the filly being able to start training without apparent lameness. Subchondral cystic lesions of the proximal sesamoid bones can be a cause of nonweightbearing lameness. Surgical debridement resulted in complete resolution of the lameness with a favourable outcome in this case.

Clinical and low field magnetic resonance imaging features of osseous cyst‐like lesions of the proximal sesamoid bones in seven horses

“…It is possible that the underlying cause in some of the cases in this series was osteochondrosis; this was speculated to be the cause of an OCLL of the PSB described by Beccar Varela et al . ().…”

“…More recently still, Beccar Varela et al . () described a subchondral bone cyst of the apical portion of the lateral PSB in a 20‐month‐old Warmblood filly that presented with an acute onset of nonweightbearing lameness; this lesion was presumed to be a manifestation of osteochondrosis since the horse had previous osteochondrosis lesions of both stifles and one tarsus.…”

The first recorded subchondral cyst‐like lesion of a proximal sesamoid bone

“…In this issue of the EVE , Beccar Varela et al . () give the first report of a cyst‐like structure in the apical portion of a proximal sesamoid bone, successfully treated by enucleation under endoscopic control. The reported features of this case are not typical of cysts at other sites; the cyst was not in the weightbearing portion of the joint and the yearling showed moderate oedema of the limb from mid metatarsus to pastern, as well as marked effusion of the metatarsophalangeal joint and digital sheath.…”

“…Ultimately the case reported by Beccar Varela et al . () merits attention not only as the first genuine subchondral cyst of a proximal sesamoid bone to be described, but also because of the rapid and apparently complete resolution of clinical signs following its surgical ablation.…”