Pseudarthrosis

Overview

Pseudarthrosis, meaning "false joint," occurs when a broken bone fails to heal. Normally a fracture knits back together over weeks to months, but in pseudarthrosis the healing process stalls and the two ends of bone remain separated, often connected by fibrous tissue rather than solid bone. This leaves the area unstable, much like an extra, unwanted joint.

Pseudarthrosis can happen after a fracture that does not unite, after spinal fusion surgery where the bones fail to fuse, or as a congenital problem present from early childhood. Congenital pseudarthrosis most often affects the shin bone (tibia) and is frequently associated with neurofibromatosis type 1. Treatment is directed by specialists and aims to get the bone to heal solidly and restore stable function.

Symptoms

Symptoms depend on the location and cause but reflect a bone that has not healed.

• Persistent pain at a fracture or surgical site long after it should have healed
• Abnormal movement or a sense of instability at the site
• Swelling or tenderness that does not settle
• Difficulty bearing weight or using the limb
• In congenital tibial cases: bowing of the lower leg and a leg that fractures easily

Persistent pain, deformity, or instability weeks or months after a fracture or fusion surgery should be evaluated, as it may indicate that the bone has not healed.

Causes

Pseudarthrosis develops when conditions needed for bone healing are not met.

• Fracture nonunion: Poor blood supply, inadequate stability, infection, or a large gap between bone ends can prevent healing.
• Failed spinal fusion: When vertebrae intended to fuse after surgery do not unite.
• Congenital pseudarthrosis: A developmental problem present from early life, most often in the tibia and often linked to neurofibromatosis type 1.
• Contributing factors: Smoking, diabetes, certain medications, and poor nutrition can impair healing.

Risk Factors

• Severe or open fractures, or fractures with bone loss
• Infection at the fracture or surgical site
• Smoking, which significantly impairs bone healing
• Diabetes and poor nutrition
• Use of certain medications such as long-term steroids
• Neurofibromatosis type 1, in congenital cases

Diagnosis

Diagnosis is based on the history, examination, and imaging.

• X-rays: The main test, showing a persistent gap or lack of healing across the fracture or fusion site, sometimes over a series of images.
• CT scan: Provides detailed views to confirm nonunion, especially after spinal fusion.
• Tests for contributing causes: Such as checks for infection, blood supply, or metabolic factors that may be preventing healing.

Treatment

Treatment is tailored to the location, cause, and the person's health, and is directed by orthopedic or spinal specialists.

• Surgery: Often required, which may include realigning and stabilizing the bone with plates, rods, or screws, and adding bone graft to encourage healing.
• Bone grafting: Using the person's own bone or graft material to bridge the gap and stimulate new bone formation.
• Treating the underlying cause: Such as clearing infection or improving stability and blood supply.
• Optimizing healing: Stopping smoking, improving nutrition, and managing conditions like diabetes.

Congenital pseudarthrosis of the tibia can be especially difficult to treat and may require more than one operation and long-term follow-up.

Prevention

Not all cases can be prevented, but several steps support healing and reduce the risk of nonunion:

• Not smoking, which is one of the most important factors for bone healing
• Following instructions on weight-bearing and immobilization after a fracture or surgery
• Managing diabetes and maintaining good nutrition
• Promptly treating any wound infection
• Attending follow-up so delayed healing is caught early

When to See a Doctor

See a doctor if pain, swelling, or instability persists at a fracture or surgical site beyond the expected healing time, or if a limb feels like it moves abnormally. Seek prompt care for:

• Increasing pain, deformity, or instability at a healing fracture
• Signs of infection such as redness, warmth, drainage, or fever
• Sudden inability to bear weight on a previously injured limb

Related Topics

Frequently Asked Questions

References

1. American Academy of Orthopaedic Surgeons (AAOS). Nonunions.
2. MedlinePlus, U.S. National Library of Medicine. Fracture healing.
3. National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS). Bone Health.
4. Children's Tumor Foundation. Neurofibromatosis and Bone.