Osseointegration: Potential complications

People undergoing osseointegration may experience the same general complications characteristic of any surgery, including those associated with anaesthesia, surgical incision, and the post-operative recovery course.

These risks are often linked to a patient’s existing health status. Our Multidisciplinary Team works to minimize avoidable complications resulting from these factors through perioperative assessment and management.

Patients may also experience complications specific to having a transcutaneous bone-anchored implant. These can include:

1. Infection
2. Hypergranulation
3. Leakage and odour
4. Periprosthetic fracture
5. Implant loosening
6. Pain
7. Revision

1. Infection:

The stoma is a permanent hole in the skin through which the bone-anchored implant connects to the external prosthesis. This hole allows local skin flora access into soft tissue.

Normally, your bodily apertures maintain a good balance between these natural florae and more harmful pathogens. However, if the stoma becomes hot, red, or swollen, or if you begin to experience discharge, this indicates that the balance has been disrupted, a greater number of pathogens and infection.

Nearly all osseointegration patients will experience one superficial infection, typically soon after surgery, until balance is reached. Around 20% (1 in 5) patients experience deep infection. Deep infections can penetrate the inner soft tissue layers or bone, causing abscesses (an inflamed collection of pus) or osteomyelitis (bone infection).

Good stoma hygiene is vital to avoid recurrent infection

Superficial infections can be treated with antibiotics. Occasionally, deep infections may require surgery to treat the infection or remove contaminated tissue. During treatment, the implant may be removed. Once the infection is clear, it can be reinserted.

2. Tissue granulation

If the implant rubs against the stoma, it can cause a potentially painful overgrowth of connective tissue known as hypergranulation.

This overgrowth can be easily treated by applying silver nitrate. The OPL implant possesses an ultra-polished surface at the interface with your skin to minimize this complication.

3. Ooze and odour

If the implant rubs, it can cause the stoma to ooze a light-yellow, translucent watery fluid, as well as bleed (particularly for patients on blood thinners). This is not a sign of infection. If the ooze becomes turbid, dense, and whitish, it may be neccessary to consult your surgeon to rule out infection.

Oozing from the stoma is dependent on individual health and lifestyle factors. Some patients may find that it happens daily; others may not experience it at all. Around 12 months after surgery, the stoma will have matured and a microbiological balance will have been reached which prevents pathogen development. Odour is related to the predominance of certain flora although, by itself, it is not a sign of infection. Our team can help you to manage ooze and odour, and our peer support group can offer further tips and tricks

4. Periprosthetic fractures:

When the bone around the implant breaks, it is known as a periprosthetic fracture. They can happen during surgery or following injury.

For osseointegration patients, periprosthetic fractures are treated surgically as other periprosthetic fractures, such as those of the knee or hip, including through standard methods of fracture fixation and restricted weight-bearing.

5. Implant loosening:

Implant loosening typically occurs when the bone fails to integrate with the implant. Less commonly, it can occur when existing implants are subject to mechanical force, i.e., through injury, or infection.

If the implant becomes loose, it will be removed. The bone bed will be checked for infection and, once excluded or cleared, the osteointegration can be reinserted.

6. Pain

All amputees can experience pain, whether using a wheelchair, a socket prosthesis or a bone-anchored prosthesis.

Osseointegrated and socket-mounted prosthetics can cause different types of pain, due to index trauma or previous surgeries or, for amputees who use prosthetics, suboptimal alignment of the prosthesis. It is crucial to distinguish between non-specific pain and pain related to your osseointegration, and to identify its source.

Osseointegration patients specifically may experience irritation of the stoma, either due to the implant or an infection, or mechanical pain or infection associated with implant loosening. Phantom pain, neuropathic sensation due to neuroma formation, or Chronic Regional Pain Syndrome, as well as deep pain caused by fascia retraction, deep scarring, or infection, may be experienced by all amputees, although they do not relate specifically to osseointegration

7. Revision

Under certain circumstances, it may be necessary to revise your osseointegration.

If the soft tissue around the stoma begins to sag, over time or with changes in your body’s habitus, it can result in painful irritation, and stump refashioning can be performed to reduce the amount of tissue around the implant.

Pain associated with neuroma growth may be addressed using Targeted Muscle Reinnervation (TMR) or Regenerative Peripheral Nerve Interface (RPNI) surgery, while long-standing infection may be addressed by debridement, and the subsequent recreation of the stoma.

If your implant becomes loose, or you suffer a deep infection, your implant may be removed during treatment and later reinserted in a two-stage process. Very rarely, when if the condition is not salvageable, it may be necessary to further shorten the residual limb, or you may decide to remove the implant and return to use of a socket prosthetic.