## Overview Bog spavin is the common term for effusion (excess synovial fluid) in the tarsocrural joint, the large uppermost joint of the hock. It appears as soft, fluctuant swellings on the front and inner aspect of the hock that communicate when pressed. Lameness may be absent or mild; the swelling itself is often mainly a cosmetic concern unless an underlying joint disease is present. ## Causes Osteochondrosis or osteochondritis dissecans in young horses, osteoarthritis, trauma, poor conformation (straight or sickle hocks), and idiopathic synovitis are the main causes. Infection produces a more painful, acute form. ## Diagnosis The characteristic soft, ballotable swelling is usually diagnostic. Radiographs or ultrasound identify osteochondral fragments or other bone changes. Synovial fluid analysis rules out infection when lameness is significant. ## Treatment Idiopathic or mild cases often need only monitoring. Rest, anti-inflammatories, and corrective shoeing help when inflammation is present. Intra-articular corticosteroids or arthroscopic removal of fragments are used for more significant underlying disease. ## Recovery and Prognosis Prognosis is good when no major bone or cartilage damage exists. Chronic effusion related to poor conformation tends to recur. Cases with osteochondritis dissecans or advanced osteoarthritis have a more guarded athletic outlook. ## Prevention Selection for good hock conformation and appropriate management of young horses with osteochondrosis reduce incidence.
soft fluctuant swelling on the front and medial hock; fluid that shifts when pressed; variable or absent lameness; occasional heat
## Overview Bog spavin is the common term for effusion (excess synovial fluid) in the tarsocrural joint, the large uppermost joint of the hock. It appears as soft, fluctuant swellings on the front and inner aspect of the hock that communicate when pressed. Lameness may be absent or mild; the swelling itself is often mainly a cosmetic concern unless an underlying joint disease is present. ## Causes Osteochondrosis or osteochondritis dissecans in young horses, osteoarthritis, trauma, poor conformation (straight or sickle hocks), and idiopathic synovitis are the main causes. Infection produces a more painful, acute form. ## Diagnosis The characteristic soft, ballotable swelling is usually diagnostic. Radiographs or ultrasound identify osteochondral fragments or other bone changes. Synovial fluid analysis rules out infection when lameness is significant. ## Treatment Idiopathic or mild cases often need only monitoring. Rest, anti-inflammatories, and corrective shoeing help when inflammation is present. Intra-articular corticosteroids or arthroscopic removal of fragments are used for more significant underlying disease. ## Recovery and Prognosis Prognosis is good when no major bone or cartilage damage exists. Chronic effusion related to poor conformation tends to recur. Cases with osteochondritis dissecans or advanced osteoarthritis have a more guarded athletic outlook. ## Prevention Selection for good hock conformation and appropriate management of young horses with osteochondrosis reduce incidence.
soft fluctuant swelling on the front and medial hock; fluid that shifts when pressed; variable or absent lameness; occasional heat