Osteoarthritis (OA) is a joint disorder that affects middle aged and older adults. It is the most common form of arthritis, and a leading cause of disability in New Zealand. It is commonly referred to as ‘wear and tear of a joint’, but the process is more complex. The primary problem is breakdown of the cartilage within the joint which then leads to bony changes and damage to other surrounding tissues such as the ligaments.
Any joint can be affected but the most common joints are the joints at the base of the thumb, the distal finger joints in the hand, the big toe joint, the knees, the hips and the spine.
Symptoms include joint pain, stiffness and reduced movement. Cracking and grinding noises can occur with joint movement.
The main risk factors for developing OA are older age, being overweight, previous injury to a joint and a family history of osteoarthritis.
The diagnosis may be possible by examination alone, but often will require some form of imaging such as a plain x-ray or ultrasound. Blood tests are usually normal.
The goal of treatment in OA is to reduce pain and to improve function. Unfortunately, there are currently no medical therapies that can reverse cartilage damage. Pain relief can be obtained from heat packs, topical pain killers (e.g. diclofenac gel and capsaicin cream) and from oral pain killers.
Weight loss and exercise to strengthen the appropriate muscles can help symptoms.
The most effective oral pain killers are usually non-steroidal anti-inflammatory medications (e.g. diclofenac, ibuprofen, celecoxib, etc.), but they have potential serious side effects, so the risks need to be balanced with the benefit. Various supplements such as glucosamine sulphate, chondroitin, omega-3 fish oil, and turmeric may provide symptom benefit. In cerrtain circumstances such as a single compartment of the knee having osteoarthritis - then a good brace to unload that compartment can provide some pain relief.
Injection treatments that can be given to treat the symptoms of osteoarthritis include. Most of these are done under ultrasound guidance to ensure correct placement of the needle to deliver the treatmet to the exact target.
1. Steroid (cortisone). This is useful to treat an acute flare of pain and can give pain relief from 6-12 weeks. Any joint can be injected.
2. Hyaluronic acid (HA). This can be considered a lubricant product that can provide benefit in mild to moderate osteoarthritis. It is typically used in large joints such as the knee or hip and if it works can provide 6-12 months of benefit.
3. Platelet rich plasma (PRP). This is derived from your own blood. Blood is centrifuged and components of blood seperated. The platelet rich component is extracted and injected back into the affected joint(s). This tends to also work best in mild to moderate osteoarthritis. If it works it can provide 6-12 months of symptom benefit. This is a safe treatment options which can be repeated as necessary.
4. Nerve blocks. The genicular nerves around the knee can be injected with anaesthetic to provide pain relief relief for those who have severe osteoarthritis of the knee where other injection therapies have failed and surgical options are not possible due to other health issues. Similarly, suprascapular nerve block can be done for severe shoulder arthritis. Occipital nerve blocks can be done for arthritis in the neck that is causing referred pain into the scalp and/or causing headaches. Duration of benefit of the nerve blocks is variable but can be hours to 6 months.