A large cyst in the distal femur of a horse

Abstract

Summary A 10‐year‐old Warmblood gelding presented with a left hindlimb lameness. Diagnostic analgesia located the lameness to the stifle. Radiography showed an unusually large cyst in the distal femur. Diagnostic arthroscopy of the stifle did not reveal any significant abnormalities. An extra‐articular transcortical approach to the cyst was performed for drainage, curettage, and provision of an autologous, cancellous bone graft, gentamicin‐impregnated collagen fleeces and injectable steroid. The horse returned to a higher level of competitive dressage than prior to surgery. This report describes a large cyst in the distal femur of a horse.

Equine bone cysts: What do we know about them and their treatment?

“…The intracystic appearance of the cyst from Skov Hansen et al . (2021) 2 years after surgery resembles erratic bone healing and is similar to the radiographic aspect of woven (immature) bone rather than lamellar (dense) bone. In fact, bisphosphonate may have hindered appropriate bone healing after the surgical treatment by preventing normal bone remodelling.…”

“…Thus, publishing case reports such as the accompanying article by Skov Hansen et al . (2021) have still tremendous value to increase our knowledge as a community.…”

“…In human subjects, there are at least five types of bone cysts that could match some of the characteristics of the cyst diagnosed by Skov Hansen et al . (2021), including non‐ossifying fibromas (NOFs), aneurismal bone cysts (ABCs), unicameral bone cysts (UBCs), intraosseous ganglia and fibrous dysplasia (Remotti and Feldman 2012). Some of their main features are detailed in Table 1 to facilitate comparison among them and with the reported cyst in the accompanying article.…”

“…Knowledge from the human literature can help determine with relative accuracy the pros and cons for the diagnosis of atypical bone cysts as the cyst reported by Skov Hansen et al . (2021). Radiographs obtained when the horse was 4 years old revealed that the cyst was eccentrically located in the physeal region and covered by a thin sclerotic rim.…”

“…In the case reported by Skov Hansen et al . (2021), only the stifle compartments were anaesthetised and this prevents objectively ruling out lameness originating from the distal limb. It has been recently reported that foot‐induced lameness can improve up to 50% in a third of horses after anaesthetising the stifle compartments (Radtke et al .…”