In this article
South Island Interventional Radiology in Christchurch assesses patients with persistent knee pain for image-guided treatment. Osteoarthritis is a common cause of knee pain, but assessment is needed to confirm the cause and discuss suitable options. Contact the team to discuss an assessment.
What is osteoarthritis?
Osteoarthritis affects the whole joint, including cartilage, bone and the joint lining. It can cause pain, swelling, stiffness and reduced movement; it does not always involve bone rubbing against bone. Age, previous injury, genetics and excess body weight can increase the risk.
Common symptoms
Most symptoms are very slow to develop and may become worse over time. One of the most common symptoms is that the knee joint is often sore during and after activity. Some people can also experience swelling, joint stiffness, reduced range of motion and an unstable knee.
The gap between conservative care and knee replacement
Treatment for knee osteoarthritis typically begins with exercise, physiotherapy, weight management where appropriate, medication, and, for some patients, joint injections. These approaches can help manage pain and maintain mobility, but they do not repair damaged cartilage or necessarily prevent osteoarthritis from progressing.
For some patients, these treatments eventually stop providing enough relief, but knee replacement may not yet be the most appropriate option. This period between conservative treatment no longer providing adequate relief and knee replacement becoming appropriate is sometimes referred to as the therapeutic gap.
Can you be too young for a knee replacement?
There is no specific age for knee replacement. The decision depends on the severity of arthritis, impact on daily life, response to previous treatments, overall health and patient preferences.
Age can still be a consideration because younger patients have more years in which revision surgery may be needed. A 2022 New Zealand Joint Registry study estimated a lifetime revision risk of 22.4% for people aged 46–50 at their first knee replacement, and 25.2% for men in that age group. These are population estimates, not a prediction for an individual patient.
However, younger patients should not automatically avoid knee replacement. When arthritis is advanced and symptoms significantly affect quality of life despite non-surgical treatment, surgery may be appropriate. The decision should be based on individual circumstances and shared decision-making.
Where genicular artery embolisation may fit
Genicular artery embolisation (GAE) is a minimally invasive procedure that may be considered for selected patients whose osteoarthritis-related knee pain persists despite appropriate non-surgical care. The evidence is still developing.
GAE targets abnormal blood flow associated with inflammation around the knee, with the aim of reducing pain and inflammation while preserving the joint. It does not rebuild cartilage, correct severe deformity or cure osteoarthritis.
An assessment for GAE may be appropriate for selected patients who:
- Continue to have significant pain despite conservative treatments
- Are not yet suitable for knee replacement
- Cannot undergo major surgery
- Wish to defer surgery after discussing the benefits and limitations
Studies have reported improvements in pain and function following GAE, although outcomes vary.
Creating time for the right decision
For suitable patients, GAE may reduce pain and improve mobility while preserving the knee joint. This can create time to stay active, strengthen the knee and consider longer-term treatment options.
GAE is not intended to replace knee replacement in patients with severe end-stage osteoarthritis, significant deformity or substantial mechanical symptoms.
The goal is to choose the right treatment at the right stage—whether that is conservative care, GAE or knee replacement.
GAE for persistent pain after knee replacement: an emerging use
Knee replacement improves pain for many people, but some have persistent pain afterwards. Estimates vary with how pain is defined and when it is measured. Persistent or worsening pain should be assessed by the treating orthopaedic team.
Small studies have reported improvement after GAE for persistent pain following knee replacement. This remains an emerging use with limited evidence, including small uncontrolled studies. Its benefit compared with standard care and its long-term risks are not yet well established.
Before considering GAE, the knee should be assessed for other causes of persistent pain, including infection, implant loosening, instability, fracture or mechanical problems. GAE cannot correct a faulty implant, but it may benefit selected patients with a stable knee replacement where ongoing inflammation is thought to contribute to their pain.