Malunion And Non Union : Classification & Types

Fractures in direct communication with the external environment or fracture hematoma in communication with the external environment are known as open fractures. They were previously known as compound fractures.

There are two main complications of an open fracture: malunion and Non-union. We will read about them today. However, it is highly advised that you know about these topics in depth if you want to pass any medical examination in India, like the NEET PG and FMGE exams.

Malunion occurs when the Fracture fragments unite in an abnormal position. If the bone's anatomy is not maintained, it may cause Shortening, alteration in posture, and Imbalance. The main cause of malunion is Improper Treatment. Malunion is more common in cancellous bone than cortical bone. Malunion is more common in Distal radius and Intertrochanteric fracture.

It is Classified into Three Types

• Length Malunion—This is also known as Overlap Malunion. The proximal and distal fragments are overridden, and the length is altered.
• Rotatory Malunion- the Proximal and distal fragments are united in the wrong fashion. Here, Normal length is maintained, but the Alignment of the fragments is altered (Rotated)
• Angulatory Malunion- Proximal and distal fragment are not present in the straight line.

It is very important to remember that remodeling can correct length and angulatory malunion to some extent, but remodeling can never correct rotatory malunion.

Some specific requirements need to be met for treatment. Deformity or angulation should be less than 10 degrees for an acceptable malunion. Also, Minimum angulation will not affect the functions of the bone and joints.

For an Unacceptable Malunion, the deformity or angulation is greater than 10 degrees, and Surgery is performed to correct it.

There are three main methods for the treatment of malunion. Osteoclasis is when the Bone is broken voluntarily, and the angulation is corrected and refixed. The second method of treatment is ORIF (Open reduction internal fixation). In this method, osteoclasis is done first, followed by straightening the angular bone. It is fixed with the help of plates and screws.

Lastly, Osteotomy can also be performed. In osteotomy, the wedge of the

Bones are cut, and the angle is fixed again. This is also known as the corrective osteotomy. It is the gold standard treatment for malunion.

Let us now discuss nonunion, the other complication of an open fracture. A fracture can be categorized as nonunion when at least nine months have elapsed since the injury or the fracture has shown no radiological signs of healing for three months.

The main Manifestation of non-union is Painless abnormal mobility in more than one plane.

Also Read: CTEV (Congenital Talipes Equinovarus) and CDH

Other symptoms, such as pain and tenderness, can also be present.

Unlike malunion, non-union type of open fracture has multiple possible causes.

• The most common cause of non-union is Inadequate immobilization and reduction. To avoid this, the Upper limb fracture should be immobilized for 6 weeks. Ischemia (No adequate blood supply)
• Infection- very common with Compound fracture
• The interposition of soft tissue
• Intact fellow bone
• Chronic systemic Illness
• It also depends on the Individual’s  bone susceptibility
• Iatrogenic means that it could be Physician-induced.
• Abnormal biomechanics of the bone, like abnormal Blood supply and viability
• Bone loss- Gap between the proximal and distal fragments
• Comminuted and Compound fracture

Muller and Weber classified it into vascular and vascular non-union to understand non-union better.

1. Vascular non-union
   1. It is also known as Hypertrophic or Hyper vascular non-union
   2. There is an Excess of callus formation between the proximal and distal fragments.
   3. In an x-ray, an Excess or exuberant callus is seen between the gaps.
2. Avascular non-union:
   1. It is also known as Atrophy
   2. There is a Lack of vascularity here.
   3. An X-ray shows a gap. The edges are tapered, and the Medial canal is not seen as it is Closed.

The treatment of non-union is also based on the vascularity classification. If it is a Vascular non-union, Open reduction and internal fixation are performed. For an avascular non-union, open reduction and internal fixation are followed by an additional step of cancellous bone grafting.

Also Read: Rib Fracture: Causes, Symptoms, Risk Factors, Diagnosis, Treatment, Prevention and Complications

Download the PrepLadder app now to access high-yield content with 24-hr Free Trial. Explore premium study resources like Video Lectures, digital notes, QBank, and Mock Tests for a seamless exam preparation. Time to begin your NEET PG coaching online with PrepLadder.