Fractures and dislocations
A fracture is a loss in the normal continuity of bone following the application of a direct or indirect force to that bone. A fracture may involve a part or the entire circumference of the cortex.
Classifications of fractures
A closed fracture is one that is not associated with a breach in the overlying skin or mucous membrane.
An open fracture is one where there is direct communication between the fracture and the externa through a breach in the overlying skin or mucous membrane. Open fractures are at significant risk for infection.
Types of fractures
- Comminuted (more than two fragments)
- Green stick - This occurs when only one cortex of the bone is seen to be fractured on the X-ray, and there is usually minimal deformity. This most commonly occurs in the paediatric age group.
- Intra-articular - Fractures that extend to the articular surface of a joint.
- Special fractures.
- Pathologic fracture - fracture through an abnormal bone.
- Stress fracture - fracture through repeated minor trauma to a normal bone (Types of fractures.).
All fractures are painful. There is normally a history of trauma except in pathological fractures where minimal trauma or no trauma is the rule. Fractures are tender, swollen, occasionally deformed, mobile at the fracture site, and associated with loss of limb function.
All suspected fractures should be X-rayed in two planes (antero-posterior, lateral) (Colles fracture. (A) Antero-posterior xray of comminuted distal radial metaphyseal fracture. Note shortening and slight radial angulation of the fracture. An important sign that denotes a fracture are overlapping cortices (arrow). (B) Lateral X-ray of comminuted distal radial fracture. Dorsal displacement, dorsal tilt and shortening is typical of a Colles fracture.).
Suspected fractures, which are not obvious on plain radiographs may be identified by bone scan, which show increased isotope uptake corresponding to the site of the fracture. This maybe less apparent in the geriatric group where an osteoblastic response may be less prominent. In the elderly, a delay of one week before bone scanning is usually required to show a positive scan. Bone scans are useful for detecting femoral neck and pelvic fractures in the elderly and carpal injuries in younger patients.
Computed tomography (CT)
CT Scans are excellent for delineating cortical and trabecular bone. The plane of the CT should be perpendicular or oblique to the fracture line to detect the fracture. CT is good for demonstrating periosteal new bone formation and may be valuable for diagnosing subtle stress fractures such as minimally displaced femoral neck fractures, pelvic ring fractures, and rib fractures.
Magnetic resonance imaging (MRI)
Limited MRI scans in the coronal or surgical plane are excellent for demonstrating fractures which are suspected but not readily apparent on plain X-rays. T1 weighted MRI's are able to detect the fracture immediately after injury and T2 weighted images can differentiate soft tissue inflammation from intraosseous oedema. MRI scans are excellent for early detection of undisplaced scaphoid and femoral neck fractures.
The principles of management of a closed fracture include
- correction of the deformity (reduction)
- immobilisation of the fracture
- protection until the fracture has consolidated
- rehabilitation of the muscles and joints of the affected limb.
Under appropriate anaesthesia (local, regional, general) the fracture fragments should be manipulated and reduced into normal alignment. In reducing the fracture, combinations of distraction, increasing and then reducing the deformity of the fracture, and holding the reduction with 3 point fixation are employed. This technique of reduction is also used with open fractures (Principles of technique of fracture reduction. (A) Most fractures are associated with fractures that are displaced, impacted and shortened. It is common that the periosteum on one side of the fracture is intact, while that of the other side is torn. (B) The first step in reducing a fracture is disimpaction where traction is applied along the axis of the bone to draw the fracture ends apart. In young patients, this may be difficult because of the very thick and resilient periosteum. (C) The next step is to increase the deformity so that the opposing ends of the fracture may be approximated. (D) The final step of reduction once the fracture ends are opposed is to correct the deformity and to apply three point fixation to hold the fracture reduction (arrows). The arrows point to areas where pressure must be applied while shaping the plaster-of-Paris cast.).
Open reduction is indicated when closed manipulation of bone fragments has failed to reduce the fracture into a satisfactory position, if reduction is impossible or if reduction is lost after initial closed reduction. Open reduction may be indicated to stabilise fractures securely to allow safe and effective management of the patients with multiple other bone or soft tissue injuries, or if movement of the adjacent joint is paramount.
Open fractures are at risk of developing infections (acute and chronic osteomyelitis). The principles of management include:
- Cleaning of contaminated tissue. This is usually accomplished by irrigation with copious amounts of sterile or antibiotic loaded irrigation solution. In heavily contaminated wounds, pulsatile irrigation devices are used to agitate the wound to assist in dislodging and diluting out foreign debris.
- Debridement of traumatised wound edges and tissue. This step is important to remove necrotic or ischemic tissue which may become foci for infection if colonised by infective organisms. Careful surgical handling of the tissue is mandatory to prevent extension of tissue injury.
- Stabilisation of fractures. Stability of the fracture is important to protect the surrounding soft tissue from further injury that may occur if the sharp fracture ends were allowed to move. The method of stabilisation is important and will depend on the extent of the soft tissue injury (see below).
- Closure of exposed bone by adequate soft tissue cover.On completion of wound debridement, the soft tissue defect may be closed either by direct suture or tissue grafts. Tissue grafts may be in the form of split skin grafts or tissue flaps. The decision regarding closure will depend on the degree of contamination and size of the defect.
Classification of open fractures
Open fractures are classified according to the severity of the injury and the modality of injury.
- Type 1: Puncture of overlying of skin or mucous membrane by a bony spike from within.
- Type 2: Laceration less than 1 cm overlying the fracture.
- Type 3: Laceration greater than 1 cm overlying a fracture.
- Type 3A: Raising of a soft tissue flap around the fracture.
- Type 3B: Absolute skin loss around a fracture.
- Type 3C: Deep and highly contaminated wound such as after a farm injury, gun shot injury and fractures associated with neurovascular injury.
Surgical considerations of open fractures
- Type 1 and 2 open fractures which can be thoroughly debrided, cleansed with copious amounts of fluid (6 litres) may be able to be fixed with internal fixation devices. Such injuries are also treated with prophylactic perioperative antibiotics for 48 hours: Keflin 1 gm i.v. 6 hourly.
- Type 3 open fractures are usually fixed with external fixation devices after thorough debridement, cleansing, and fracture reduction. Frequently soft tissue reconstruction is required to provide closure of the wound: Keflin 1 gm i.v. 6 hourly.
- Type 3C injuries are associated with a poor prognosis and amputation may be required in up to 60% of 3C injuries. A course of antibiotics is usually prescribed and the selection of antibiotics will depend upon the type of contamination introduced into the wound: Vancomycin 1 gm i.v. 12 hourly (adjusted to preand postadministration levels) and ceftriaxone 1 gm i.v. 12 hourly.
Minor fractures such as those effecting the phalanges of the fingers may be treated using small metal or plastic splints.
Plaster of paris cast
Plaster of Paris cast immobilisation is a conventional method of immobilising the fracture following closed reduction. This may be either a completely encircling moulded cast or an incomplete encircling cast (plaster slab).
Some fractures, particularly those involving the lower limb, may be treated temporarily or definitively by the application of traction along the line the limb. Traction encourages normal alignment of the fracture and the increased tension of the surrounding soft tissue helps to provide internal splintage of the fracture.
External fixation is the application of transfixing pins and bars to create a construct that lies external to the limb and acts to hold the fracture following either open or closed reduction. This method of immobilisation is selected if unstable fractures cannot be held using traditional non-operative techniques. External fixation is also indicated when an open and contaminated fracture is at risk of infection and therefore must be held immobilised by a system which does not introduce into the wound any foreign material such as metal plates and screws.
Internal fixation is indicated when closed reduction has failed, when further displacement is anticipated, when closed non-operative immobilisation constitutes a risk to the patient, or when internal fixation allows earlier mobilisation, rehabilitation and earlier return to normal function. Internal fixation includes the use of transfixing wires, inter fragmentary screws, metal plates, and intra-medullary rods.
Fractures treated with closed reduction are said to have united when no mobility occurs at the fracture site. Early union is normally associated with some tenderness on stressing of the fracture whilst complete union and consolidation is said to be evident when there is no tenderness of the fracture site and stressing does not reproduce symptoms of pain. Radiographic assessment of union is made by observing the development of fracture callous and the gradual disappearance of the fracture line.
Rigid and internal fixation with internal fixation devices may reduce the amount of callus formation and because of the rigidity of the fracture immobilisation may make clinical assessment of union difficult. When fractures have been openly reduced and internally fixed the union is assessed using radiographs to demonstrate the disappearance of the fracture line.
All healing fractures must be protected against refracture by gradually permitting stresses along the fractured bone that is commensurate with the strength of that healing bone. In the lower limb, this may be undertaken as a combination of graduated weight bearing of the fractured limb and the use of external supports such as crutches, splints and braces after 6 to 8 weeks of non-weight bearing. In the upper limb, weighted activity may commence after 4–6 weeks.
Bleeding may occur from laceration of adjacent soft tissue, vascular structures or through fracture ends. Significant amounts of bleeding may occur into soft tissue depending upon the bone fracture, e.g. closed femoral fractures may loose up to 2 litres of blood into the thigh, and pelvic fractures up to 4 litres into the pelvic cavity.
Infection is a risk for all open injuries.
Some fractures extend from bone into the joint. Displacement of articular fragments must be treated by anatomic reduction to reduce the risk of post-traumatic arthritis.
Excessive bleeding or swelling into the soft tissue may induce a compartment syndrome where excessive pressures within a tissue compartment prevents adequate blood flow to that compartment. Unless this is treated expediently necrosis of soft tissue and subsequent scarring may cause loss of limb function or loss of the limb itself. The signs of a compartment syndrome are dominated by pain that is not responsive to analgesia. Increasing pain following limb surgery mandates an examination to exclude a compartment syndrome. Other signs of limb ischemia include pallor, paraesthesia, paralysis, poikylothermia, and pulselessness.
Delayed union occurs when a fracture has not united in a period of time that is at least 25% longer than the expected average time for fracture union at that site. The causes of delayed union include inadequate immobilisation, infection, avascular necrosis of bone, and soft tissue interposition between fracture ends. Delayed union is assessed radiographically.
Non-union is said to have occurred when no evidence of union is seen on sequential X-rays over a six-month period of time. Non-union is associated clinically with movement or pain at the fracture site. If there is copious amounts of callus formation but without bridging of the fracture a state of hypertrophic non-union is said to exist and requires rigid internal fixation for cure. If there is no evidence of callus formation, then a state of hypotrophic non-union is said to exist and bone grafting and internal fixation is required for treatment.
Mal-union occurs when the fracture unites with a loss of anatomical alignment. Mal-union by shortening may be acceptable but angulation and rotation of the bone following union may not be acceptable and may interfere with normal function.
On removal of a plaster cast, the joints adjacent to a fractured limb require rehabilitation to prevent or treat stiffness. This involves passive and active range of motion exercises and proprioception exercises to improve the sense of balance in the recovering joint. In addition, it is important to return the strength and endurance of the muscles in the injured limb by a regime of exercises.
Limbs treated with internal fixation may undergo earlier mobilisation because the fracture is usually more stable than those treated by plaster immobilisation.