Clinical history A 5 yr castrated male mixed breed dog presented to the emergency service with pain in the left pelvic limb - there was no history of trauma - pain was present on palpation of the left stifle joint. A single lateral radiograph was made of the left stifle joint. Single lateral radiograph - What is your diagnosis? Radiographic diagnosis The single lateral study was incorrectly evaluated as a normal study without evidence of injury to the joint. The owner was advised to return if clinical signs continued. Additional radiographs were made of the left limb 1 month later that included the hip joint - What is your diagnosis ?? The additional radiographs included a lateral of the right stifle for comparison - Does this assist in your diagnosis ?? Radiographic diagnosis
- Malformed left distal femur with caudal angulation centered on the distal metaphysis
- No signs of a destructive/productive lesion
- No signs of periosteal response
- A focal lucency within the dorsal cortex is at the site of closure of the distal physeal plate
- Most likely diagnosis is a malunion fracture of the femur without evidence of injury to the stifle joint
- The left hip joint is not normal and should be examined further
- Further palpation showed crepitus in the left hip joint - radiographs were made of the pelvis
Radiograph of the pelvis Final radiographic diagnosis
- Malunion fracture of the distal femur with shortening of the femur and caudal angulation of the distal femur at the fracture site
- Nonunion fractures of the pubis and ischium
- Healed right sacroiliac luxation with malunion
- Malunion fracture of left acetabulum and/or fracture of the left femoral neck with resulting traumatic arthrosis
Comments It is always a risk to take only a lateral radiograph even in the middle of the night on emergency service There is always a positive value in having a comparison radiograph of the opposite limb if the original study appears differently than you expect
