What happens if a bone stimulator doesn't work?

In rare cases, a fracture does not heal, resulting in a nonunion. If a prescribed bone growth device is unsuccessful, individuals will need to understand what happens if a bone stimulator doesn't work and pursue alternative treatment strategies, which often involves further evaluation and surgery.

Quick Summary

When a bone stimulator is ineffective for a nonunion fracture, the patient requires further medical evaluation to diagnose the cause and determine if alternative treatments, such as surgery, are needed.

Key Points

• Professional Assessment is Crucial: If healing does not progress, a doctor's evaluation with advanced imaging is the necessary next step.

• Addressing Underlying Issues: Successful treatment requires identifying and correcting the root cause of nonunion, such as infection, poor blood supply, or mechanical instability.

• Surgical Intervention is Common: Alternative therapies often involve surgery, such as bone grafting or internal fixation, especially for severe or complex cases.

• Lifestyle Impacts Healing: Factors like smoking and poor nutrition can negatively affect bone healing and may contribute to bone stimulator failure.

• Numerous Surgical Options Exist: From bone grafts to plates and screws, a range of surgical techniques can effectively treat nonunions when stimulation fails.

• Adjunctive Therapies Are Available: In some cases, treatments like higher-intensity ultrasound or special biologics, such as BMPs, can be used to augment healing.

A bone stimulator is a medical device used to encourage the healing of bone fractures, particularly in cases of delayed union or nonunion. Nonunion is a permanent failure of a broken bone to heal, while a delayed union is a fracture that is taking longer than average to heal. A bone stimulator may use electrical or ultrasound waves to stimulate the body’s natural healing process at the fracture site. However, this treatment is not always successful. When it fails, it signifies that the underlying issues preventing healing have not been adequately addressed, necessitating a reevaluation of the treatment plan.

Recognizing Bone Stimulator Failure

Signs and Symptoms

Failure of a bone stimulator is typically indicated by a lack of progress in the fracture healing process. The most common signs and symptoms include:

• Persistent pain: Pain at the fracture site that continues or worsens over the months following treatment, even after the initial healing period. Nonunion pain can last for years if left untreated.
• Continued mobility: Feeling movement or instability at the fracture site, which can be a key indicator that the bones are not fusing together.
• Lack of radiographic progress: Follow-up imaging, such as X-rays, shows little to no evidence of new bone growth or callus formation across the fracture gap.
• Swelling: Continuing or recurring swelling around the site of the injury can signal an ongoing problem.

Diagnosing the Problem

If a bone stimulator is not effective, your doctor will perform a thorough evaluation to diagnose the root cause of the nonunion. This may involve:

• Medical history and physical exam: Your doctor will review your history, including your use of the stimulator and any lifestyle factors that may impact healing.
• Advanced imaging: X-rays, CT scans, and MRIs can provide detailed views of the fracture site to assess the extent of nonunion and identify any underlying issues.
• Blood tests: Blood tests may be used to check for infection, nutritional deficiencies (like vitamin D), or other systemic conditions that could inhibit healing.

Common Reasons Why a Bone Stimulator Might Not Work

Bone stimulator failure is often a symptom of underlying biological, lifestyle, or mechanical issues that inhibit proper bone healing. Some of the most common reasons include:

Biological Factors

• Inadequate Blood Supply: A steady blood supply is crucial for delivering the nutrients and cells needed for bone healing. Some fractures occur in areas with poor blood flow, which can lead to nonunion despite stimulation.
• Infection: Chronic, low-grade infections can prevent healing. The presence of bacteria can interfere with the bone regeneration process.
• Systemic Conditions: Chronic diseases such as diabetes or severe anemia can impair the body's natural healing capabilities.

Lifestyle and Nutritional Factors

• Smoking and Nicotine: Use of tobacco products significantly slows blood flow and impairs the body's healing process, making it a major risk factor for nonunion.
• Poor Nutrition: A diet lacking essential nutrients, such as protein, calcium, and vitamins C and D, can hinder bone healing.
• Medication: Certain medications, including anti-inflammatory drugs like NSAIDs and corticosteroids, can impact healing.

Mechanical and Procedural Issues

• Inadequate Stabilization: A fracture requires stability to heal. If there is excessive movement at the fracture site, the bone stimulator is unlikely to succeed.
• Misuse of the Device: For external stimulators, consistent and correct daily use is critical. Inadequate patient compliance can lead to failure.
• Large Fracture Gap: The bone stimulator may not be effective if the fracture gap is too large.

Device-Related Problems

• Malfunction or Recall: In rare cases, the device itself may malfunction. In 2018, Zimmer Biomet recalled thousands of bone growth stimulators due to manufacturing concerns, highlighting the risk of device failure.

Alternative Treatment Pathways Following Failure

If a bone stimulator proves ineffective, your doctor will likely recommend more aggressive treatment to address the underlying nonunion. These options are often surgical but may also include other adjunctive therapies.

Surgical Options

• Bone Grafting: This procedure involves transplanting healthy bone tissue to the nonunion site to provide a scaffold and a source of new, living bone cells.
  • Autograft: Bone is harvested from another part of the patient's body (often the pelvis).
  • Allograft: Bone from a cadaver is used, reducing harvest site pain.
• Internal Fixation: This involves surgically implanting metal hardware, such as plates, screws, or rods, to hold the bone fragments together and provide the necessary stability for healing. A revision surgery may be performed to use a larger or more rigid implant.
• External Fixation: In cases of severe infection, bone loss, or complex fractures, an external fixation device may be used. This rigid frame is attached to the bone with pins and wires from outside the body.

Other Modalities

• Advanced Biologics: In addition to grafts, doctors may use biological substances like Bone Morphogenetic Proteins (BMPs) or Platelet-Rich Plasma (PRP) to stimulate the biological environment and promote healing.
• High-Intensity Ultrasound: In some cases, a higher intensity, non-invasive ultrasound may be tried, especially after initial surgical failure.

Comparing Nonunion Treatments

Treatment	Description	Pros	Cons
Bone Stimulator	Non-invasive or invasive device emitting waves to encourage healing.	Least invasive, high patient compliance with implanted devices.	Variable effectiveness, requires consistent patient use, device failure is possible.
Surgical Fixation	Stabilizing the fracture with plates, screws, or rods.	Provides immediate stability, high success rates with proper technique.	Invasive, risk of infection, hardware failure, requires skilled surgeon.
Bone Grafting	Transplanting bone tissue to the fracture site.	Provides scaffold and growth factors to restart healing.	Can cause pain at harvest site (autograft), donor tissue risks (allograft).
Advanced Biologics	Using proteins like BMP or PRP to enhance biological healing.	Can accelerate healing, especially in difficult cases.	Higher cost, newer methods, may have specific use cases.

Conclusion

If a bone stimulator doesn't work, it is a clear indication that more aggressive intervention is needed to achieve bone union. The failure should be addressed through a thorough medical evaluation to identify the root cause, which may be biological, mechanical, or patient-related. While a failed bone stimulator can be discouraging, numerous surgical and advanced treatment options, such as bone grafting, internal fixation, and advanced biologics, are available. Patients should consult with their orthopedic surgeon to create a personalized and comprehensive treatment plan, increasing the chances of a successful recovery.

For further information on nonunion diagnosis and treatment, visit the National Center for Biotechnology Information.

Frequently Asked Questions

How do you know if a bone stimulator isn't working?

Signs that a bone stimulator may not be working include persistent pain at the fracture site, limited mobility, continued swelling, and a lack of progress in bone healing as observed on follow-up X-rays.

What are the main reasons for bone stimulator failure?

Common reasons include poor blood supply to the fracture site, infection, inadequate immobilization of the bone, lifestyle factors like smoking, and systemic diseases like diabetes.

Is surgery the only option if a bone stimulator fails?

Not always, but it is a very common and often necessary step for established nonunions. Surgery is typically recommended if the failure points to an underlying mechanical issue or if non-invasive methods have been exhausted.

What is a bone graft and how does it help?

A bone graft involves transplanting healthy bone tissue, either from the patient (autograft) or a donor (allograft), to the nonunion site. It provides a scaffold and growth factors to jump-start the healing process.

What is internal fixation?

Internal fixation is a surgical procedure that uses metal hardware, such as plates, screws, or rods, to provide stability to the broken bone fragments. It is often combined with a bone graft to promote healing.

Can lifestyle factors, like smoking, affect the stimulator's effectiveness?

Yes, smoking and nicotine use are significant risk factors for nonunion. They constrict blood vessels and impede the blood flow essential for healing, potentially leading to the failure of a bone stimulator.

What is the first step after suspecting my bone stimulator isn't working?

You should schedule a follow-up appointment with your orthopedic surgeon immediately. They will conduct a re-evaluation, likely including new imaging studies, to determine the next steps.