Delayed Union and Non-union- What Is It?

Introduction:

Around 100,000 fractures become nonunion every year in the United States. Fracture healing is a very essential clinical event for both the patients and the clinicians dealing with fractures. The risk factors associated with delayed union and nonunion include advanced age, medical comorbidities, smoking, using non-steroidal anti-inflammatory drugs, metabolic diseases, nutritional deficiencies, and genetic disorders.

What Is the Delayed Union Of A Fracture?

A delayed union refers to the bone that takes comparatively longer time to heal than what was expected, but healing eventually happens without any additional surgery.

What Does Nonunion Mean?

Nonunion is when the body is unable to heal the fracture. If the fracture persists for more than nine months without exhibiting any sign of healing for three months, it can be referred to as non-union.

How To Assess Nonunion?

Assessment of a patient with nonunion can be done with the help of the patient's clinical history and some physical examinations, along with imaging studies and laboratory tests. The main points that need to be checked on the clinical history are pain with weight bearing and subjective fracture instability. The physical examination is done to focus on the tenderness or motion at the site of the fracture. It also depends on the extent of the deformity, status of the soft tissue envelope, indications of infection, and range of motion at the joints that are right adjacent to the fracture site.

What Causes Nonunion In A Fracture?

Nonunions occur if there is a lack of stability in the bone or blood blow and in some cases, both. It can also happen if the injury to the bone happens due to some high-impact trauma, such as a car accident because these sorts of injuries often impair blood supply to the broken bone.

What Are The Risk Factors Associated With Nonunion?

There are several risk factors associated with nonunion. Some are :

• Old age

• Consumption of tobacco or nicotine in any form, like smoking, chewing tobacco, or using nicotine gum or patches. This increases the chances of nonunion by inhibiting bone healing.

• Diabetes.

• Cases of severe anemia.

• Hypothyroidism.

• Low levels of Vitamin D.

• Poor nutrition.

• Infection.

• Consumption of medication consists of anti-inflammatory drugs like Aspirin and Ibuprofen.

How Is Blood Supply Related To Nonunion Of A Fracture?

Nonunions are even more likely if there is a limited blood supply in the bone. Things might be different for different bones, though.

• The toe bones can be expected to heal faster because of their inherent stability and excellent blood supply.

• The upper thigh bone and the small wrist bone have limited blood supply that can also be destroyed when the bones break.

• The shinbone has a moderate blood supply but can be disrupted by an injury. A high-impact injury can damage the skin and muscles over the bone, further destroying the external blood supply. The injury can also destroy the internal blood supply that is found in the marrow present at the center of the bone.

What Are The Symptoms Of Nonunion?

The major symptoms generally include pain at the site of the injury after the initial pain of the fracture diminishes. The pain can last from months to years. The pain might be constant or might be felt when that particular arm or leg is used.

What Causes A Delayed Union?

Some major causes of delayed union of fracture are :

• Inadequate blood supply.

• Severe soft tissue damage.

• Periosteal stripping.

• Excessive traction.

• Infections.

• Insufficient splintage.

What Are The Clinical Symptoms That A Delayed Union Of Fracture Exhibit?

Among all the major clinical features, the most common ones are:

• Instability at the site of the fracture.

• Persistent and constant pain at the site of the fracture.

• Non-weight bearing.

• Muscle atrophy.

How Is A Delayed Union And Nonunion Diagnosed?

For proper diagnosis, the podiatrist first uses imaging studies that provide them with pictures of the bones and surrounding tissues in detail. Tests like X-rays and computed tomography scans are done depending on which bone is involved. The doctor might conclude the case as a case of nonunion if there is

• Persistent pain at the site of the fracture.

• A constant gap at the fracture site with no bone spanning in between.

• If the healing is not being done in a time period, that is generally enough for normal healing.

• If no progress in bone healing is seen by comparing repeated imaging studies over months.

On diagnosing nonunion of fracture, the doctor will prescribe some more blood tests to get to the root cause of the problem. The tests might reveal if there is any infection or other medical conditions causing slow bone healing, such as anemia or diabetes.

How Is Delayed Union And Nonunion Of Fracture Treated?

There are both non-surgical and surgical ways of treating this issue. Both ways have their own set of advantages and disadvantages.

• The Non-surgical Treatment: Some cases of nonunions and delayed unions can be treated non-surgically too. The most commonly used one is a bone stimulator that delivers ultrasonic or pulsed electromagnetic waves that, in turn, stimulate healing. The patient places this device on the skin over the site of nonunion from 20 minutes to several hours daily. This should be done daily to see some good results.

• The Surgical Treatment: There are various surgical techniques for treatment, but surgical ways should only be considered when the non-surgical ones fail. Some surgical techniques are :

  • Bone Grafting - Bone grafting further has two methods - Internal fixation and external fixation.

  • Allograft.

  • Using bone graft substitutes or osteobiologics.

How to Prevent Nonunions And Delayed Unions?

One needs to stop consuming tobacco completely for proper prevention. One needs to follow their doctor's advice in a very disciplined manner, along with maintaining a proper lifestyle and balanced diet. A balanced and healthy diet provides the body with the nutrients it needs for growing and healing.

Conclusion:

Lastly, both delayed unions and nonunions are difficult to treat and have a huge financial impact if surgical intervention is needed, but not treating them would be fatal.