A Labrador retriever with clinical problems in the right hip The only history of interest in this male Labrador was that he sustained a traumatic event when 5 years of age - at that time, radiographs were made of the pelvis using a “frog-leg” positioning with the pelvic limbs flexed. A ventrodorsal radiograph showed luxation of the right femoral head in an otherwise normal hip joint without evidence of associated fracture of either acetabulum or the femoral head A single lateral radiograph of the pelvis was made at that time following an open reduction of the luxation showing replacement of the femoral head A study of the pelvis was made 26 months later when the dog was 7 years old - at that time the patient had shown chronic lameness - What is your diagnosis at this time? Radiographic diagnosis Destructive/productive lesions in the right hip
- Lesions in both the femoral head and the acetabular cup - (arrows)
- Joint space is collapsed dorsocranially
- Periosteal new bone around the acetabulum and on the femoral neck
Secondary arthrosis of the left hip joint probably associated with hip dysplasia Diagnosis - osteomyelitis with infectious arthritis, right hip
- Positive culture of Pseudomonas aeruginosa
An FHO was perfomed on the right side - an immediate post-operative radiograph was made The dog continued to be lame following the surgery and radiographs of the pelvis were made 2 months following the FHO - what is the cause of the lameness?? Radiographic diagnosis Progressive osteolytic lesions in both acetabulum and surface of the osteotomy site in the femur - (arrows) Diagnosis - persistent osteomyelitis Comparison radiographs at the time of the FHO and 2 months post op - note in particular the progression of lytic changes in the greater trochanter Comments The pattern of radiographic changes following the first surgery was that of osteolysis involving bone tissue on both sides of the joint space - in addition, the inflammatory lesion stimulates a poorly defined periosteal response - this pattern is typical for that of a bacterial bone/joint infection. Primary bone tumors usually affect only one bone and are usually epiphyseal or metaphyseal in location. Metastatic tumors usually do not produce a periosteal response distant from the destructive lesions and are usually diaphyseal and not within a joint. Synovial cell sarcomas are usually polyostotic on both sides of a joint but produce well defined lytic lesions with only minimal periosteal response and a strong soft tissue component. Fungal bone/joint infection is usually more productive/sclerotic. It is interesting to note the development of secondary arthrosis in the left hip as seen on the last study after the left hip was evaluated as normal at 5 years of age.
