Pseudoarthrosis, often referred to as a “false joint,” is a condition when a bone fracture fails to heal properly. Instead of forming solid bone, the fracture site develops fibrous tissue or cartilage, leading to persistent instability and discomfort, affecting mobility and quality of life.
How Pseudoarthrosis Develops
Normal bone healing is a complex biological process that typically occurs in several overlapping stages. Initially, an inflammatory response begins, followed by the formation of a soft callus, which then matures into a hard callus composed of new bone. The final stage involves remodeling, where the new bone is refined and strengthened. Pseudoarthrosis disrupts this natural progression, resulting in a “non-union” where the bone fragments do not fully bridge the gap. Instead of forming a solid bony connection, the body creates a flexible, fibrous tissue resembling a joint at the fracture site.
This condition can manifest in two primary forms: atrophic and hypertrophic pseudoarthrosis. Atrophic pseudoarthrosis is characterized by inadequate blood supply and diminished bone-forming activity. Conversely, hypertrophic pseudoarthrosis involves the formation of excessive but unorganized callus due to ongoing mechanical instability at the fracture site.
Recognizing the Signs
Pseudoarthrosis often causes persistent pain at a previous fracture or surgery site, particularly with weight-bearing activities or movement. Individuals might also experience a lack of mobility, joint clicking, swelling, or tenderness in the affected area.
In some instances, if nerves are affected, symptoms can extend to numbness, tingling, or weakness in the limbs. While some individuals with pseudoarthrosis may not experience any symptoms, the presence of these signs often prompts medical evaluation.
Diagnosis primarily relies on medical imaging techniques to identify the presence of a non-union and assess its characteristics. X-rays, Computed Tomography (CT) scans, and Magnetic Resonance Imaging (MRI) are commonly used. A physical examination also contributes to the diagnostic process, and CT scans are often considered effective for detailed assessment.
Factors Leading to Pseudoarthrosis
The development of pseudoarthrosis is influenced by biological, mechanical, and patient-related factors that impede the natural healing process. Biological factors include conditions that compromise the body’s ability to repair bone, such as poor blood supply to the fracture site, infections, or underlying systemic diseases like diabetes and osteoporosis. Malnutrition, poor diet, and vitamin D deficiency can also deprive the body of essential nutrients for bone regeneration.
Mechanical factors relate to the stability and environment of the fracture. Excessive movement or instability at the fracture site prevents bone from establishing a solid bridge. Insufficient immobilization or premature weight-bearing before the bone has adequately healed can also lead to a non-union. Surgical aspects, such as inadequate bone grafting, improper placement of fixation devices, or insufficient stabilization during initial treatment, may also increase the risk.
Patient-related factors encompass individual habits and medical history. Smoking is a notable risk factor, as it restricts blood flow and impairs the body’s healing capacity. Older age and the long-term use of certain medications, including corticosteroids, are also associated with an increased likelihood of developing pseudoarthrosis. Alcohol consumption can additionally affect the healing process.
Treatment Approaches
Treating pseudoarthrosis often requires a targeted approach to achieve bone union and restore function. Initially, non-surgical options may be explored, including the use of electrical stimulation devices to promote healing. Bracing or physical therapy might also be employed to provide support and improve mobility. Pain management strategies, such as medications, can help alleviate discomfort. However, these conservative measures may have limited effectiveness in many cases.
Surgical intervention is frequently necessary, especially when non-surgical treatments prove insufficient. A primary surgical technique involves bone grafting, where bone tissue is used to bridge the non-union gap and stimulate new bone growth. This can involve an autograft (patient’s own bone), an allograft (donor bone), or synthetic alternatives.
Internal fixation is commonly used in conjunction with grafting to stabilize the bone fragments. This involves the application of plates, screws, rods, or bolts to hold the bone in proper alignment during healing. Revision surgery might be performed for previously failed fusions. The goal of these treatments is to achieve a solid bone union and enable a return to normal activity.