What is our main concern with most bone pathologies?
-Increased feature risk.
How are fractures classified?
- Location (mid shaft, proximal, distal)
- Type (open/compound or closed, level of disruption, character of the pieces)
- Pattern of fracture
How do fractures present?
- PAIN, lack of mobility
- Diagnosis via XRAY
What are the 4 steps of fracture healing?
- Hematoma formation (1-2 days after injury). Blood clot forms from damaged tissues. Large clot forms in 2-5 days. Fibrosis begins at the end of week 1.
- Fibrocartilaginous callus (soft tissue) forms. Collagen is secreted by fibroblasts. Osteoblasts begin depositing osteoid into the matrix and edges of fibrocartilaghinous collar connects the bone fragments. Maximal girth in 2-3 weeks. Stabilizes fracture
- Bony callus formation: 3rd or 4th week. Osteogenic cells in area become osteoblasts and initially form trabecular.spongey bone. Radiographic union occurs when all of the fibrocartilage has become spongey bone. Cast may be taken off now.
- Remodeling. Dead bone is reabsorbed by osteoclasts. Osteoclasts re-establish medullary canal. Bone is reorganized along lines of mechanical stress. Compact bone forms along shaft.
What are the bone healing times for: kids, teens, adults?
- Kids: 4-6 weeks
- Teens: 6-8 weeks
- Adults: 10-18 weeks
What type of fractures heal the slowest?
Long bone, displaced, fractures with less surface area.
What is osteomyelitis, and when does it become chronic?
-Bone bacterial infection, >6-8 weeks is chronic.
What are the three routes of bone infection?
- Hematogenous: blood borne
- Contiguous: infection of tissue
- Exogenous: direct traumatic introduction from the external environment.
Who usually gets hematogenous osteomyelitis?
-Kids or adults with compromised immune systems.
What is the most common cause of HO? What are it’s signs?
- Staphylococcus aureus, can bind to collagen and enter bone
- Signs are typical bacterial infection signs: fever, pain, erythema, swelling.
Where does HO usually present?
Metaphysis of bone due to the vascular supply there.
What is the traditional long term progression of HO?
- Infection progresses forming a pocket of puss in bone.
- This pus pocket decreases vascular supply to a portion of bone, resulting in necrosis.
- Fragmentation occurs (fragments are called sequestra) leading to more necrosis.
- New bone, called involcrum, forms around sequestra.
How is HO treated?
-Antibiotics, surgical drainage.
Who is likely to get contiguously spread osteomyelitis?
- People with diabetes and wounds on their feet.
- People with infected open wounds
- People with tuberculosis (most usually impacts the vertebra
What is osteonecrosis and what are some potential causes?
Bone death due to improper blood flow. Potential causes include:
- Fracture
- Thrombus
- Embolism
- Infection of vasculitis
- Vascular compression
- Corticosteroid use
What is the most commonly involved site for osteonecrosis?
-The hip.
How is osteonecrosis treated?
Immobilization, limited weight bearing, hyperbaric oxygen, non steroidal anti-inflammatories, joint replacement.
What do neoplasms of bone most commonly occur as?
Primary or metastatic lesions.
What type of cancers commonly metastasize to bone?
-Prostate, lung, breast.
What can bone neoplasms involve?
Bone, marrow, cartilage.
What is a sarcoma?
A malignant bone neoplasm.
What is an osteoma? A chondroma?
Both are benign.
Osteoma is in bone.
-Chondroma is in cartilage.
What is an osteochondroma?
- Unusual lateral outgrowth of cartilage.
- Common in young individuals, makes up 35% of all benign tumors.
What are some characteristics of being neoplasms?
- Many are asymptomatic and go undiagnosed.
- Defined borders, slow growing.
