What it is.
Crystal arthritis is inflammation caused by crystals forming inside a joint. Two types matter:
- Gout. Monosodium urate crystals, forming when uric acid in the blood is persistently high. Classically the base of the big toe, but the knee is a common site and the hip is possible.
- Pseudogout, or calcium pyrophosphate deposition. Calcium pyrophosphate crystals. More common with age, and the knee is the most frequently affected joint.
An attack comes on quickly, often overnight, and produces a joint that is hot, red, swollen and exquisitely painful. Some people run a fever.
Why it matters on a joint replacement site.
Two reasons, both practical.
It mimics infection. A hot, swollen, acutely painful joint with a fever is septic arthritis until proven otherwise, and septic arthritis destroys a joint within days. The two cannot be reliably separated on examination or on blood tests. Aspirating the joint and examining the fluid, for organisms and for crystals, is what distinguishes them. The default position is to assume infection and investigate, not to assume gout because the patient has had gout before. People with gout also get infections.
It complicates joint replacement. An attack in the days after surgery is easily mistaken for a prosthetic joint infection, and that mistake can lead to unnecessary surgery. It runs the other way too: assuming a hot replaced joint is just gout can delay treatment of a genuine infection. Where crystal arthritis is known, it is documented before surgery and the perioperative plan takes it into account.
It is not osteoarthritis.
Osteoarthritis builds over years and hurts on loading. Crystal arthritis arrives over hours and hurts constantly, including at rest. The two coexist frequently, particularly pseudogout and knee osteoarthritis, and calcification of the meniscus on an X-ray, called chondrocalcinosis, is a common incidental finding that points to it.
Treatment.
Acute attacks are managed medically with anti-inflammatories, colchicine or corticosteroids, and long-term prevention of gout is with urate-lowering therapy. That is your GP's or rheumatologist's work, not a surgeon's.
What matters here is that it is diagnosed properly rather than assumed, and that it is declared before surgery. Crystal arthritis does not prevent joint replacement, and does not in itself damage an implant.
Common questions.
How do I know if it is gout or an infection?
You often cannot tell from symptoms alone, and neither can a doctor on examination. Both cause a hot, swollen, very painful joint and both can cause fever. The joint needs to be aspirated and the fluid examined for organisms and for crystals. Assume infection until it is excluded.
Can I still have a joint replacement if I have gout?
Yes. Gout does not prevent joint replacement and does not damage an implant. It does need to be declared beforehand so that a post-operative attack is not mistaken for infection, and so the medication plan accounts for it.
What is chondrocalcinosis?
Calcium crystal deposition visible on an X-ray, often in the meniscus of the knee. It is a common incidental finding with age and indicates a predisposition to pseudogout. On its own it does not require treatment.
My knee flared up after surgery. Is that gout?
It might be, and it might be infection. That distinction is made by aspirating the joint, not by assuming. Contact the rooms rather than waiting.
Does gout cause arthritis?
Long-standing untreated gout can cause joint damage and secondary arthritis, which is one reason urate-lowering treatment matters between attacks.
References.
- Dalbeth N, Gosling AL, Gaffo A, Abhishek A. Gout. Lancet. 2021;397(10287):1843-1855.
- Rosenthal AK, Ryan LM. Calcium pyrophosphate deposition disease. N Engl J Med. 2016;374(26):2575-2584.
This page provides general information about a medical condition and a surgical procedure. It is not individual medical advice and does not replace consultation with a qualified practitioner. Outcomes vary between individuals and all surgery carries risk. A referral is needed for a consultation with Professor Daevyd Rodda; without one, you can start with the practice nurse practitioner, who can provide it.