Femur
Panosteitis
Osteosarcoma
Trauma/fractures
Panosteitis
Signalment
Breeds – Large and giant breeds, especially German shepherd dogs and Bassett hounds
Gender – Males are more commonly affected, but females are also affected
Age – 5 months up to 2 years (although it is uncommon after 1 year of age)
Etiology – Unknown, but nutrition and genetics may play a role. A viral cause has also been postulated.
History
Mild to moderate lameness, often moves between different limbs, may be lethargic with decreased appetite.
Clinical Findings
Mild to moderate lameness, pain on palpation of diaphysis of long bones
Diagnostics
Radiographs are helpful, but not always diagnostic depending on stage. There may be attenuation of trabecular patterns in the proximal and distal aspects of the diaphysis. This may be followed by the development of patchy densities, especially around the nutrient foramen of bones. The periosteum may demonstrate reactive changes, followed by thickening of the cortices. CT may also be helpful.
Treatment Options
Rest, nonsteroidal anti-inflammatory drugs, change to large dog growth diet or adult dog food
Osteosarcoma
Signalment
Breeds – Large and giant breeds
Gender – No apparent predilection
Age – Median age is 7 years, but cases may also occur between 18-24 months of age
Etiology – Unknown, but may have a genetic basis
History
Progressive lameness that may progress to severe lameness with development of a pathologic fracture, owners may notice swelling of the affected area, weight loss, and poor appetite in later stages of the condition.
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Clinical Findings
Mild to moderate lameness, swelling of the distal femur, pain on palpation, possible crepitus and instability if a pathologic fracture is present.
Diagnostics
Radiographs of femur and chest radiographs or CT for evaluation of metastatic disease. Fine needle aspirate or biopsy is recommended to confirm clinical suspicions.
Treatment Options
Amputation with chemotherapy gives the best prognosis with a median survival time of approximately 1 year. Amputation alone gives palliative pain relief, but does not prolong survival. Other limbs and joints should be assessed to be certain that the dog can cope with an amputation. Euthanasia is also an option.
Trauma/fractures
Signalment
Breeds – Any breed
Gender – No gender predilection
Age – Any age
Etiology – Trauma. Many cases occur as a result of automobile trauma. Because of this and the fact that the pelvic limb is affected, careful evaluation of the thoracic and abdominal structures is important to detect cardiac arrhythmias, pneumothorax, pulmonary edema, diaphragmatic hernia, urinary tract trauma, or internal hemorrhage.
History
Often owners witness trauma, such as a fall, hit by automobile, or other sudden traumatic event that results in sudden onset of severe lameness.
Clinical Findings
Fractures of the femur result in pain and crepitation during manipulation of the limb.
Diagnostics
Radiographs are generally diagnostic, but CT evaluation may give additional details.
Treatment Options
Most fractures of the femur require internal fixation to restore anatomy and function. Depending on the size and age of the dog, the fracture configuration and number of fragments, intramedullary pins, interlocking nails, or bone plate and screws may be used to repair femur fractures. Cerclage wire, hemicerclage wire, and screws placed in neutral or lag fashion may be used to reconstruct bone fragments prior to applying the primary form of fixation. External skeletal fixators may be used, but there is morbidity associated with penetration of the pins through muscles.
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