Concurrent or sequential tibial subchondral cystic lesions in 4 horses with medial femoral condyle subchondral cystic lesions

Abstract

CASE DESCRIPTION 4 horses were examined because of signs of chronic hind limb lameness. CLINICAL FINDINGS 3 horses had a history of lameness for > 6 months; specific duration was unknown for 1 horse. On initial evaluation, grade 3 to 4 (on a scale from 1 to 5) hind limb lameness was present in all 4 horses. Radiography of the stifle joint of the affected limb revealed medial femoral condyle subchondral lucencies or subchondral cystic lesions (SCLs) in all 4 horses, medial femorotibial osteoarthritis in 3 horses, and medial tibial condyle SCLs in 3 horses. TREATMENT AND OUTCOME 2 horses were treated medically (stall rest and oral NSAID administration), and 2 horses were treated surgically by means of medial femoral transcondylar lag screw placement through the medial femoral condyle SCLs. The 2 horses treated medically did not improve and were euthanized. Necropsy confirmed the presence of medial femoral condyle and medial tibial condyle SCLs. Surgical treatment did not resolve the lameness in 1 horse with SCLs in the medial tibial condyle and medial femoral condyle, and euthanasia was performed 150 days after surgery. In the second horse, a medial tibial condyle SCL was evident on radiographs obtained 3 months after surgery; however, this was not addressed surgically, and signs of lameness resolved 11 months after surgery. CLINICAL RELEVANCE Results of this small case series suggested that SCLs in the medial tibial condyle can occur in association with SCLs of the medial femoral condyle, with a poor prognosis for return to athletic function in affected horses. Further investigation is indicated.

Stimulation of subchondral bone cyst healing by placement of a transcondylar screw in the equine medial femoral condyle

“…The FEM also predicts increases in stress in the medial meniscus with an SBC due to altered load transfer. This finding is in line with clinical information revealing secondary injuries to the meniscus and proximal tibia, which reduce treatment success rates . Therefore, incomplete healing or enlargement of the SBC after treatment may impact long‐term soundness.…”

“…This finding is in line with clinical information revealing secondary injuries to the meniscus and proximal tibia, which reduce treatment success rates. 10,11 Therefore, incomplete healing or enlargement of the SBC after treatment may impact long-term soundness. It is likely that substantial radiographic healing of an SBC will provide a more durable reduction in lameness.…”

Highlights of recent clinically relevant papers

“…This study by Alvaro Bonilla and colleagues in the USA and Canada reports on four horses with concurrent or sequential tibial subchondral cystic lesions with medial femoral condyle subchondral cystic lesions .…”

Subchondral lucencies of the proximal tibia in 17 horses

“…Proximal tibial SCL occur in the medial or lateral condyle . Lateral proximal tibial SCL are most often on the axial and cranial aspect of the tibia and are commonly the sole radiographic abnormality.…”

“…They are more common in the first year of life, usually without radiographically confirmed signs of osteoarthritis (OA), and have been suggested to be the result of osteochondrosis . Medial proximal tibial SCL are most often caudal and abaxial and secondary to an MFC SCL or, less commonly, OA . Conservative therapy for lateral tibial SCL in a limited number of horses has been reported to achieve poor rates of achieving athletic function .…”