Fractures: Types and Overview
- Fractures can involve part of, or all of the bone cortex
- Open fracture – the skin or overlying mucous membrane is breached
- Closed – there is no damage to the overlying skin or mucous membrane
Types of Fracture
- Fractures are always painful!
- Often involve trauma (except for pathological fractures)
- Often swollen
- Mobile at fracture site
- Loss of limb function
X-ray – the investigation of choice.
- All suspected fractures should be x-rayed from 2 planes! – AP, and lateral. This allows you to judge the level of displacement, comminution, angulation and rotation.
Bone scans – if you can’t see a fracture on X-ray, but you still highly suspect one, then you might do a bone scan. There is increased Tc uptake at sites of fracture, so fractures will appear dark on bone scan.
- This effect is less apparent in older patients due to reduced osteoblastic responses to the scan. In such patients, you might have to wait one week between giving the radioactive isotope and performing the scan.
- Particularly useful for femoral neck and sacral injuries in the elderly, and carpal tunnel injuries in the young.
CT – useful if you can’t see anything on x-ray. Make sure the scan is perpendicular to the fracture line!
- CT is also very good at detecting new bone formation, and so can detect subtle stress fractures.
MRI – once again, useful if x-ray looks normal. MRI’s can be especially good, as a T1 scan can show the fracture immediately, (bone scans and CT can take a while), whilst T2 are good for showing up older fractures.
General Complications of Fracture
- Leg pumps
- LMW heparin (in selected patients!)
- May lead to avascular necrosis - this usually occurrs in the hip, but can occur at the end of any long bones, sometimes without associated fracture! Tends to occur within 48 hours of fracture. Needs to be treated with a total hip replacement (THR). X-ray will be normal in the early stages, but in the late stages, affected bone areas will be darker than normal bone, due to collapse of subchondral bone.
- Generally rare, but well recognised
- Usually associated with open, high energy fractures.
- Signs include; cold pulseless limb, ischaemia, paralysis and parasthesia of the limb
- If there is ischaemia, you should presume there is arterial disruption until proven otherwise.
- Angiography confirms the diagnosis
- Treated with surgery to revascularise the limb. Also, often just closing an open fracture can help perfusion.
- You may use a temporary vascular shunt to prevent damage whilst more permanent surgery is performed
- The limb should be fixated before you operate on the vessels
Nerve Injury – particularly if the fracture affects the knee (common peroneal nerve). Look for foot drop and loss of sensation on the dorsum of the foot. The majority of nerve injuries are traction neuropraxia – i.e. the nerve remains intact, but is temporarily unable to transmit nerve impulses. These will subsequently recover. Prognosis for nerve injury is generally good, but many patients might not make a complete recovery. It is important to make detailed notes and examination of nerve injury before surgery – as if the nerve injury is only noted after surgery, the surgeon may be liable.
- Mal-union – the separate areas of bone heal, but with incorrect alignment. Proper placement and reduction of the fracture at the time of injury can prevent it.
- Nonunion – the separated areas of bone do not fuse. More common in smokers. Often occurs when a fracture is ‘missed’ on x-ray and thus the correct treatment is not administered (e.g. immobilisation in a cast). There is usually some tissue development between the two fractured pieces. This can be scar tissue, or more rarely, a pseudo joint forms with cartilaginous articulating surfaces. If union has not occurred by 6 months, then it is unlikely to do so without intervention. Typically a diagnosis of non-union requires an x-ray at >6 months demonstrating non-union of the fractured ends of the bone.
- Delayed union – difficult to distinguish between delayed and non-union. X-ray at 6 months is definitive. In both instances the joint is likely to be painful throughout.
- Can be early or late
- Gas Gangrene - Infection, usually by chlostridium, that produces gas within tissues. Rare.
- This typically occurs in the hand or foot after injury, sometimes after only mild injury. It occurs after about 5% of all trauma injury, and can also occur after frostbite and long periods of immobilisation.
- It results from injury to the sympathetic nervous system which inturn, affects the blood supply to the affected region.
- Typical features include:
- Burning pain in the affected area
- Skin changes – skin often becomes thinned and shiny
- excessive sweating – at the affected site
- Pain stiffness and muscle wasting may become worse with progression, as the patient is reluctant to use the affected body part.
- It can often be successfully treated with physiotherapy, although this can be a lengthy process