Total Knee Replacement Workers' Comp in California — Authorization, Surgery, and Permanent Disability

When does workers' comp cover a knee replacement?

When a job injury or years of wear damaged your knee, and a doctor says a replacement is needed. Both sudden and slow injuries count.

There are two ways a knee becomes a work injury. The first is one bad moment. You fall from a ladder. A load drops on your leg. Your knee twists on a wet floor. The second builds up over time. Years of kneeling, squatting, and lifting wear the joint away.

Both kinds are covered in California. A slow wear injury has a special start date. Under Labor Code 5412, your clock begins the day you knew the damage came from work. That is usually the day a doctor first links your bad knee to your job.

You also do not need work to be the only cause. It only has to be a real cause. So even if your knee was aging, a job that pushed it over the edge still counts. Some workers need a partial knee. Others need the full joint. Comp covers whichever one your surgeon picks.

All needed care is paid in full. Labor Code 4600 makes the insurer cover your visits, your scans, your surgery, and your therapy. You pay no copay. You pay no deductible. The bills go to the company, not to you.

How do you get the knee surgery approved?

Your doctor asks the insurer to approve it. A review can say no. If they deny it, you appeal to an outside doctor within 30 days.

Most knee surgeries get approved, but rarely on day one. The insurer runs your doctor's request through a check called utilization review. A reviewer you never meet can approve it, delay it, or deny it.

Insurers usually want you to try other steps first. Think shots, braces, and therapy. They follow a state rulebook called the MTUS. Once those steps fail and your scan shows bone on bone, a new knee is usually approved.

What gets a knee approved is clear proof. Your X-ray or MRI should show the worn joint. Your records should show that shots and therapy did not fix it. A detailed report from your surgeon ties it all together. We help your doctor build that file.

If they deny the surgery, do not give up. You can appeal to an outside doctor. This is called Independent Medical Review. Labor Code 4610.5 gives you only 30 days to file. So move fast.

One more thing about your doctors. You usually must pick them from the insurer's network, called the MPN. If your doctor is not helping you, you can switch to another one inside that network.

What do you get paid while you recover?

While you cannot work, you get temporary disability. It pays about two-thirds of your wages. The checks can run up to 104 weeks.

Recovery from a new knee takes time. Most people need months before they walk well again. A job on your feet can keep you out even longer. While you heal, you should not lose your income.

Temporary disability pay covers most of your lost wages. It runs about two-thirds of your weekly pay. Your first check is due within 14 days of your lost time. If it shows up late, the insurer owes a 10 percent penalty.

This pay does not last forever. Labor Code 4656 caps it at 104 weeks within a 5 year window. For most knee cases, that is enough time to heal. Here are the 2026 numbers.

How is a replaced knee rated, and can they blame old wear?

A new knee leaves lasting damage, so it earns an award. The insurer may blame old wear to cut it. Make them prove the split.

A replaced knee is never quite the same as a young, healthy one. So it always carries a permanent rating. Once your knee is as healed as it will get, a doctor scores the lasting damage from 0 to 100 percent.

That score turns into money. Under Labor Code 4660.1, the rating also shifts for your age and your job. Harder jobs often land on the higher end. A rating of 70 percent or more adds a lifetime monthly check called a life pension. The table below uses the 2026 top rate.

Now the biggest fight on a knee case. It is called apportionment. The insurer argues that part of your bad knee comes from old age or old wear, not your job. Every share they pin on the past is a share they do not pay.

The law does not let them guess. Labor Code 4663 says the split must be based on real cause. Their doctor has to explain how much came from work and how much did not, with a medical reason. A doctor who just says "half is your old arthritis" has not met that test. And the boss only pays for the part your job truly caused.

Your award is not the only thing you get. The insurer also keeps paying for your knee. A new joint does not last forever. Years later it can wear out and need a second surgery, called a revision. Future medical care covers that too. Do not sign it away in a fast settlement without advice.