Pathological Fractures: X ray Imaging, Clinical Features and Treatment

Pathological fracture result from normal force acting on abnormal bone (weak bone)

Most commonly caused by osteoporosis but also maybe due to tumors, infection or inherited bone disorders
The term pathological fractures previously used for tumors that cause fractures only but nowadays it also used to describe fractures caused by metabolic bone disease and osteomyelitis
The term insufficiency fracture means fracture caused by repetitive trauma on osteoporotic bone
Fragility fracture caused by minimal trauma on osteoporotic bone

Causes

Metabolic bone disease: osteoporosis, osteomalacia, Paget disease, osteogenesis imperfecta …
Bone Infection: osteomyelitis
Bone tumors: benign and malignant, primary and secondary; e.g. osteosarcoma, lymphoma, myeloma
Most commonly, primary bone tumors both benign and malignant occur in children and adults younger than 40
Secondary metastasis more common patients older than 40
Most frequently carcinomas that metastasize to bone are lung, breast, thyroid, renal and prostate
Most common sites of metastasis are spine, proximal femur and pelvis

History

Same orthopedics trauma history explained in one of the previous videos in this class titled “history taking and examination in orthopedic trauma” but you need to pay attention to some details including:

Bone fractures spontaneously or after mild trauma
History of pain and swelling at the fracture site before it occurs
Ask about the past medical history for previous illnesses and operations, looking for previous diagnoses with tumors regardless of how long it was
History of malignant tumor maybe the source of metastatic lesion, patient present with weight loss, pain, lump, cough or hematuria in this context
History of gastrectomy, intestinal malabsorption, chronic alcoholism or prolonged drug therapy should suggest a metabolic bone disorder
In younger patients, history of previous fractures may suggest a diagnosis of osteogenesis imperfecta

Examination

Same orthopedics trauma examination explained in one of the previous videos in this class titled “history taking and examination in orthopedic trauma” but you need to pay attention to some details including:

General examination: look for characteristic appearances of congenital dysplasia’s, Cushing’s syndrome and Paget’s disease ..
Examine chest, neck, breasts, abdomen, prostate and test for lymphadenopathy
Same Orthopedic examination: Look – feel – move
Neurological examination should be done with attention because in many cases the nerves are affected by the lesion

X ray Imaging

Focus on the coming points while investigating an x ray of a pathological fracture

Type and location of the fracture in the body, e.g. vertebral compression fracture maybe due to severe osteoporosis, metastases or myeloma
Look for the location of the fracture on the bone. If long bone then (diaphysis, metaphysis, epiphysis)
If the fracture associated with a lesion then focus on:

Location of the lesion: (medullary, endosteal, cortical, periosteal)
Look for the zone of transition between lesion and normal bone tissue: well defined margin (means non aggressive pathology) vs ill defined margin (aggressive pathology)
Look at the lesion matrix, could be lytic lesion in MM and metastases, could be fibrous lesion which appears as ground glass on x ray and occur in fibrous dysplasia; could be cumulous cloud in osteoid lesion, popcorn in cartilaginous lesion, could be soap bubbly in cystic lesions
Also look at the morphology of the lesion which could be circular, ovoid …
Look for periosteal reaction to the lesion: could be smooth/benign periosteal reaction in benign lesions, could be hair on end in fast growing, could be lamellated in moderately growing lesion and could be codman triangles in rapid rate of growth of a lesion
Look for extra osseous or soft tissue involvement

Hellerhoff, CC BY-SA 4.0 , via Wikimedia Commons

Other investigations

Radiological investigations looking for tumors includes x rays, ct scan, bone scan, MRI depending on suspicion
Labs looking for metabolic bone disease (CBC, ESR, vit D, calcium, SPEP..) and tumor related tests
Biopsy if the disorder not diagnosed by previous tests

Treatment

Same treatment principles explained in the management of fractures videos (reduce – hold – exercise)
With treatment of the underlying pathology caused the fracture to occur
Internal fixation is advised as a holding method for most of the cases to prevent refracturing and in cases when bone healing is impaired
Internal fixation method used should be strong enough to bear the weight of the patient because bone healing might be impaired too
Pathological fracture near bone end can be treated with excision and arthroplasty, especially hip fractures