Pseudarthrosis

Pseudarthrosis (from Greek pseudes — false and arthron — joint) is a pathological condition characterized by a persistent disruption of bone integrity, resulting in abnormal mobility at a previous fracture site.

This is the outcome of an injury where the biological healing process has completely stopped, making spontaneous recovery impossible.

Etiology and pathophysiology

The formation of pseudarthrosis occurs when there remains a gap between bone fragments or regular micro-movement is present. The main causes include insufficient immobilization, premature limb loading, soft tissue interposition between fragments, or local disruption of blood supply.

At the cellular level, the process of bone formation ceases. The ends of the bone fragments become covered with scar tissue, become denser (sclerotic), and close off with bone sealing plates. The bone marrow canal is completely enclosed with scar tissue. A dense fibrous capsule forms around the nonunion site.

Clinical significance

Clinically, the pathology manifests from painless to moderately painful mobility in the area of the false joint, deformation, local muscle atrophy, and impairment of segment function.

Radiographically, a gap between the fragments, characteristic rounding and smoothing of their ends, and complete closure of the bone marrow canal are clearly visualized. The treatment of the false joint is exclusively surgical. It requires the excision of scar tissues, opening of the bone marrow canals, and stable fixation of the fragments.