Fracture Complications and Healing: A Comprehensive Overview

QUESTION

Fractures are common: most people will experience at least one during a lifetime. With modern medical and surgical care most heal without problems or significant loss of function. However, fractures are associated with a range of complications. Acute

complications are generally those occurring as a result of the initial trauma and include neurovascular and soft tissue damage, blood loss and localised contamination and infection. Delayed complications may occur after treatment or as a result of initial treatment and may include malunion, embolic complications, osteomyelitis and loss of function.

The risk of complications varies with the particular fracture, its site, circumstances and complexity, with the quality of management, with patient-specific risk factors such as age and comorbidities, and with post-fracture activities such as air travel and immobility.

Risk factors

Fracture complications are often variably defined, and there is a lack of consensus in their assessment, which makes their incidence difficult to estimate. Complications clearly vary with fracture site and nature and with quality of surgery but many also vary with patient attributes such as:

• Age.
• Nutritional staus.
• Smoking status.
• Alcohol use.
• Diabetes (type 1 or type 2).
• Use of non-steroidal anti-inflammatory drugs (NSAIDs) within 12 months.
• A recent motor vehicle accident (one month or less prior to fracture).
• Oestrogen-containing hormone therapy (although this may be a proxy for osteoporosis).

Normal fracture healing

The process of normal fracture healing involves:

• Inflammation – with swelling, lasting 2-3 weeks.
• Soft callus formation – a decrease in swelling as new bone formation begins, fracture site stiffens. This takes until week 4-8 post-injury and is not visible on X-ray.
• Hard callus formation as new bone bridges the fracture site. This is visible on X-ray and should fill the fracture by weeks 8-12 post-injury.
• Bone remodelling – the bone remodels to correct deformities in the shape and loading strength. This can take several years, depending on the site.

For healing to happen the site needs adequate stability, a blood supply and adequate nutrition. Healing rates vary by person, and are likely to be compromised by the risk factors above and by age and comorbidity.

Fracture complications such as excessive bleeding or soft tissue compromise, infection, neurovascular injury, presence of complex bone injury, such as crushing or splintering, and severe soft tissue trauma will clearly prolong and possibly hinder or prevent this healing process.

Early complications

Life-threatening complications

• These include vascular damage such as disruption to the femoral artery or its major branches by femoral fracture, or damage to the pelvic arteries by pelvic fracture.
• Patients with multiple rib fractures may develop pneumothorax, flail chest and respiratory compromise^[1] .
• Hip fractures, particularly in elderly patients, lead to loss of mobility which may result in pneumonia, thromboembolic disease or rhabdomyolysis.

Local

• Vascular injury.
• Visceral injury causing damage to structures such as the brain, lung or bladder.
• Damage to surrounding tissue, nerves or skin.
• Haemarthrosis.
• Compartment syndrome (or Volkmann’s ischaemia)^[2] .
• Wound Infection – more common for open fractures.
• Fracture blisters^[3] .

Systemic

• Fat embolism^[4] .
• Shock.
• Thromboembolism (pulmonary or venous).
• Exacerbation of underlying diseases such as diabetes or coronary artery disease (CAD).
• Pneumonia.

Compartment syndrome

See the separate Compartment Syndrome article.

Fat embolism

See the separate Fat Embolism Syndrome article.

Fracture blisters

These are a relatively uncommon complication of fractures in areas where skin adheres tightly to bone with little intervening soft tissue cushioning. Examples include the ankle, wrist, elbow and foot.

Fracture blisters form over the fracture site and alter management and repair, often necessitating early cast removal and immobilisation by bed rest with limb elevation. They are believed to result from large strains applied to the skin during the initial fracture deformation, and they resemble second-degree burns rather than friction blisters. They may be clear or haemorrhagic, and they may lead to chronic ulcers and infection, with scarring on eventual healing. Management involves delay in surgical intervention and casting. Silver sulfadiazine seemed in one review to promote re-epithelialisation.

Risk factors, other than site, include any condition which predisposes to poor skin healing, including diabetes, hypertension, smoking, alcohol excess and peripheral arterial disease.

Late complications of fractures

Local

• Delayed union (fracture takes longer than normal to heal).
• Malunion (fracture does not heal in normal alignment).
• Non-union (fracture does not heal).
• Joint stiffness.
• Contractures.
• Myositis ossificans^[5] .
• Avascular necrosis.
• Algodystrophy (or Sudeck’s atrophy).
• Osteomyelitis.
• Growth disturbance or deformity.

Systemic

• Gangrene, tetanus, septicaemia.
• Fear of mobilising.

Problems with bone healing (non-union, delayed union and malunion)

Delayed union is failure of a fracture to consolidate within the expected time – which varies with site and nature of the fracture and with patient factors such as age. Healing processes are still continuing, but the outcome is uncertain.

Non-union occurs when there are no signs of healing after >3-6 months (depending upon the site of fracture). Non-union is one endpoint of delayed union. The distinction between delayed union and non-union can be slightly arbitrary: whilst fractures can generally be expected to heal in 3-4 months, this will vary in the case of open fractures and those associated with vascular injury, and also in the presence of patient risk factors described below. However, non-union is generally said to occur when all healing processes have ceased and union has not occurred.

Malunion occurs when the bone fragments join in an unsatisfactory position, usually due to insufficient reduction.

ANSWER

Fracture Complications and Healing: A Comprehensive Overview

Fractures are a common occurrence, with the majority of people experiencing at least one in their lifetime. Although most fractures heal well with modern medical care, they can lead to various complications. These complications can be categorized into acute and delayed, each with distinct causes and impacts on healing.

Acute complications arise from the initial trauma and include neurovascular and soft tissue damage, blood loss, and localized contamination and infection. Delayed complications may result from treatment or initial injury and involve malunion, embolic issues, osteomyelitis, and functional loss. The risk of complications varies based on fracture type, location, management quality, patient-specific factors, and post-fracture activities.

Risk factors influencing fracture complications encompass age, nutritional status, smoking, alcohol consumption, diabetes, use of non-steroidal anti-inflammatory drugs, recent motor vehicle accidents, and more. Fracture healing involves distinct stages: inflammation, soft and hard callus formation, and bone remodeling. Adequate stability, blood supply, and nutrition are crucial for successful healing.

Early complications can be life-threatening, involving vascular and visceral damage, pneumothorax, and loss of mobility. Systemic complications such as fat embolism, shock, thromboembolism, and exacerbation of underlying diseases also occur. Fracture blisters, a lesser-known complication, form over tightly adhering skin to bone, requiring specific management.

Late complications include delayed union, malunion, and non-union, each impacting the healing process. Delayed union involves healing beyond the expected timeframe, while non-union signifies an absence of healing after an extended period. Malunion results from inadequate fragment alignment during healing.

In conclusion, fractures encompass a range of complications that can adversely affect healing and functional outcomes. Acute and delayed complications vary based on factors such as fracture site, nature, quality of care, and patient attributes. Recognizing and addressing these complications are vital for optimal fracture management.