Can joint fusion be used in severe OA? 

Joint fusion, clinically known as arthrodesis, is a surgical procedure where the two bones forming a joint are permanently joined together, effectively eliminating the joint space. In the context of severe osteoarthritis, this is a highly effective treatment used primarily for smaller joints, such as those in the ankles, feet, wrists, or spine, where the protective cartilage has completely worn away. While a fusion removes the ability to move that specific joint, it is exceptionally successful at eradicating the chronic, debilitating pain caused by bone-on-bone friction. Following NHS and NICE guidelines, joint fusion is generally considered when other surgical options, like joint replacement, are either not feasible or unlikely to provide a durable result. For many patients, the trade-off of losing a small amount of motion for a total resolution of pain is a significant improvement in their overall quality of life and functional independence. 

What We’ll Discuss in This Article 

• The clinical procedure of joint fusion and how bone growth is achieved. 

• Identifying which joints are most suitable for arthrodesis in severe OA. 

• The primary benefit of permanent pain relief compared to joint replacement. 

• Common causes of severe joint wear that necessitate a fusion procedure. 

• Identifying triggers and signs that indicate conservative care has failed. 

• Differentiating between joint fusion and joint replacement options. 

• Understanding the recovery process and the long-term impact on mobility. 

The Procedure: How Arthrodesis is Performed 

Joint fusion is a significant surgical undertaking performed under general or regional anaesthesia. The surgeon begins by removing the remaining damaged cartilage and roughening the surfaces of the bones that form the joint. This creates a biological environment similar to a fracture, triggering the body’s natural bone-healing response. The bones are then positioned in a functional alignment and held securely in place using internal hardware, such as metal plates, screws, or rods. 

Over a period of several months, the two bones grow together into a single, solid unit of bone. Once this fusion is complete, the joint no longer exists, and therefore, it can no longer generate arthritic pain. In the UK, this procedure is often performed in specialised orthopaedic units. While the internal hardware is usually left in place permanently, the ‘success’ of the surgery is determined by the biological union of the bone, which provides a stable and pain-free limb for the long term. 

Suitability: Which Joints Are Commonly Fused? 

Arthrodesis is not suitable for every joint in the body. While it is highly effective for stability and pain relief, losing motion in large joints like the hip or knee would cause significant walking difficulties. Therefore, fusion is primarily reserved for joints where stability is more important than a full range of motion, or where modern joint replacements are not yet as durable. 

Commonly fused joints in the UK include: 

• The Ankle and Midfoot: This is a gold-standard treatment for severe post-traumatic ankle OA, providing a stable base for walking. 

• The Big Toe (First MTP Joint): Fusion is very common for severe ‘hallux rigidus’ (stiff big toe), allowing for a comfortable push-off when walking. 

• The Wrist: Often used for advanced wear after old fractures, allowing the patient to maintain strong grip strength without pain. 

• The Spine: Facet joint fusion (often with a disc replacement or ‘cage’) is used to stop painful movement in an unstable spinal segment. 

• Small Finger Joints: Specifically, the joints closest to the fingernails (DIP joints), which can become very painful and crooked in hand OA. 

The Requirement of Failing Conservative Management 

Following NICE guidelines, joint fusion is a ‘terminal’ procedure, meaning it cannot be reversed. Because of this, UK clinicians require that patients have exhausted all appropriate non-surgical and less invasive surgical options first. Surgery is only recommended when a person’s quality of life is severely compromised, and their pain is no longer managed by daily self-care. 

Conservative management that must be attempted includes: 

• Therapeutic Exercise: Specifically focused on strengthening the muscles around the joint to provide better support. 

• Orthotics and Bracing: Using specialized boots, insoles, or wrist splints to mechanically stabilize the joint. 

• Pharmacological Support: Consistent use of topical and oral anti-inflammatories to manage flares. 

• Activity Modification: Learning how to ‘pace’ activities to avoid overloading the worn joint. 

• Steroid Injections: Using localized injections to provide a temporary window of relief. 

The Underlying Causes of Severe OA Requiring Fusion 

Severe osteoarthritis that leads to a recommendation for fusion is often the result of years of chronic wear, but it is frequently accelerated by specific clinical factors. Unlike primary OA, which is often age-related, the joints that require fusion often have a history of significant mechanical trauma or structural instability. 

Key clinical causes include: 

• Post-Traumatic Arthritis: This is the most common cause for ankle fusion; a past fracture that damaged the joint surface irrevocably. 

• Chronic Instability: Long-term ligament damage (such as recurrent ankle sprains) that leads to abnormal joint ‘shear’ and cartilage death. 

• Failed Previous Surgery: If a joint replacement has failed or become infected, fusion is often the ‘salvage’ procedure used to restore stability. 

• Severe Bony Deformity: When a joint has become so crooked that it can no longer bear weight or function in a neutral position. 

• Inflammatory Destruction: In some cases of rheumatoid arthritis, the small joints of the foot or wrist become so damaged that fusion is the only way to restore function. 

Differentiation: Joint Fusion vs Joint Replacement 

The choice between fusion and replacement is a critical one and depends heavily on the specific joint involved and the patient’s lifestyle. In the UK, this is a collaborative decision made between the orthopaedic surgeon and the patient, weighing the desire for motion against the need for permanent stability. 

Key points of differentiation include: 

• Motion vs Stability: Replacement aims to keep the joint moving. Fusion stops all movement to provide absolute stability and total pain relief. 

• Durability: Artificial joints can wear out or loosen over twenty years. A successful fusion is permanent and will never ‘wear out.’ 

• Activity Levels: Fusion is often better for patients who perform heavy manual labour, as artificial joints are more likely to fail under high-impact stress. 

• Recovery: Fusion usually requires a longer period of total immobilisation (such as a cast) to allow the bone to knit together, whereas replacement patients are encouraged to move immediately. 

Recovery and Long-Term Impact on Mobility 

Recovering from a joint fusion requires patience. Because the goal is for the bones to grow together, the joint must be kept completely still during the initial healing phase. This usually involves a cast or a specialised brace for six to twelve weeks. During this time, the UK clinical team will monitor the progress of the bone union through regular X-rays. 

Once the fusion is solid, patients usually find that their mobility is surprisingly good. For example, after an ankle fusion, the other joints in the foot often ‘take over’ some of the lost movement, allowing the person to walk with a near-normal gait on flat ground. However, because the fused joint no longer moves, the joints above and below it have to work harder. Long-term, this can sometimes lead to increased wear in those adjacent joints, a process called ‘adjacent segment disease.’ This highlights the importance of continuing with the strengthening exercises provided by your physiotherapist to protect the rest of your limb. 

Conclusion 

Joint fusion is a highly effective surgical solution for severe osteoarthritis, particularly in the smaller, high-stress joints of the feet, ankles, and wrists. By permanently joining the bones, it provides a level of pain relief that is often superior to other surgical options, albeit at the cost of joint movement. While it is a major procedure that requires a significant recovery period, most patients find the trade-off worthwhile to regain their independence and return to a life free from chronic arthritic pain. If you have failed conservative treatments, a discussion with a specialist can help determine if this permanent solution is the right clinical step for you. 

According to NHS guidance on ankle fusion, the procedure is exceptionally successful at relieving pain and allowing patients to return to daily activities. 

If you experience severe, sudden, or worsening symptoms, call 999 immediately. 

Authority Snapshot 

This article was written by Dr. Stefan Petrov, a UK-trained physician with an MBBS and postgraduate certifications including Basic Life Support (BLS), Advanced Cardiac Life Support (ACLS), and the UK Medical Licensing Assessment (PLAB 1 & 2). Dr. Petrov has extensive hands-on experience in general medicine, surgery, and emergency care, having worked in both hospital wards and intensive care units. He is dedicated to medical education and ensuring that patient-focused health content is accurate, safe, and aligned with UK clinical standards.