Knee Arthritis & Total Knee Replacement

What is knee arthritis?

The knee is where the thigh bone (femur), shin bone (tibia) and kneecap (patella) meet. Smooth cartilage covers the ends of the bones and a pair of C-shaped menisci act as shock absorbers. In osteoarthritis, the most common type, that cartilage thins and roughens over years. As it wears, the bones may form spurs, the joint space narrows, and the lining of the joint becomes inflamed.

Risk goes up with age, previous injury such as a meniscus or ligament tear, higher body weight, family history, and the alignment of your legs. Arthritis can also follow fractures or be caused by inflammatory conditions such as rheumatoid arthritis.

What does knee arthritis feel like?

Typical symptoms are aching along the inside, outside or front of the knee, stiffness after sitting or in the morning, swelling, and a grinding or catching feeling. Early on, pain flares with stairs, kneeling or long walks and eases with rest. Later it can hurt at night and with every step. Some people notice the knee bowing inward or outward, or giving way.

What can I try before surgery?

A good non-surgical program works for many people for a long time, and it is also the right starting point for people who eventually need surgery. Common elements are:

• Weight loss when it applies, since each pound lost takes about four pounds of load off the knee with each step
• Physical therapy and a home strengthening program for the quadriceps and hip muscles
• Low-impact exercise such as cycling, swimming and walking
• Anti-inflammatory medicine or topical creams when they are safe for you
• A cane in the opposite hand or an unloader brace for some people
• Cortisone injections for short-term relief of a flare

These treatments reduce symptoms but do not regrow cartilage. If they stop being enough, replacement is the next step.

When does knee replacement make sense?

The decision is about how much the knee limits your life, not only what the X-ray looks like. Dr. Stepanyan is more likely to recommend replacement when:

• Pain interrupts sleep or is constant, even at rest
• Walking, stairs or getting up from a chair are limited
• You have tried therapy, medicine and injections and still hurt
• X-rays show advanced arthritis that matches your symptoms
• Pain or a bowed alignment keeps you from work, family or activities you care about

In a randomized trial of 100 patients with moderate to severe knee arthritis, those who had knee replacement followed by a non-surgical program reported greater improvement in pain, function and quality of life at one year than those who had the non-surgical program alone. The surgery group also had more serious complications, which is a real trade-off to weigh.¹

What happens in a knee replacement?

Dr. Stepanyan removes the worn surfaces of the thigh bone and shin bone and caps them with smooth metal and plastic components shaped to fit your knee. In a total knee replacement, the underside of the kneecap may also be resurfaced. Surgery usually takes about an hour to an hour and a half.

Robotic assistance with MAKO. For appropriate patients, Dr. Stepanyan uses the Stryker MAKO robotic-arm system. A CT scan of your knee is turned into a 3D plan before surgery. In the operating room, the robotic arm keeps the saw within the boundaries of that plan so bone cuts match it closely and soft-tissue balance can be checked as the knee is moved. The surgeon guides every step; the robot does not act on its own.

Long-term results, including how long the implants last and whether patients are happier years later, are still being studied, and anyone who promises otherwise is going beyond the evidence.

Most patients stay one night or go home the same day, depending on health and on how the day goes.

How long does a knee replacement last?

A review of studies and national registries with at least 15 years of follow-up estimated that about 82% of knee replacements were still working at 25 years.² Many of those implants were older designs, and modern implants are expected to do at least as well, but no one can promise a result. Younger and more active patients place more wear on implants over time.

What are the risks?

Knee replacement is one of the most common and successful operations performed, but like any surgery it carries risks. They include infection, blood clots, stiffness, persistent pain, loosening or wear of the implant over the years, and injury to nearby nerves or vessels. Dr. Stepanyan takes steps to lower these risks, including antibiotics, blood-clot prevention, early walking and attention to your heart, lung and diabetes control before surgery. Stiffness is the most common problem to manage, and committed rehabilitation is the best defense against it.

Should I get a second opinion?

If you have been told you need a knee replacement and want to be sure, or you were told you are too young or too heavy, a second opinion is reasonable. Request a visit and bring your X-rays and any MRI.

Where can I see Dr. Stepanyan?

Dr. Stepanyan sees knee patients in Glendale, East LA and Santa Fe Springs. He operates at Adventist Health Glendale, Glendale Memorial Hospital, Adventist Health White Memorial and White Memorial Montebello, Providence Saint Joseph Medical Center and Avalon Surgery Center.

What does recovery look like?

These are typical stages after a total knee replacement. Your own plan from Dr. Stepanyan and your therapist may differ.

1. Day of surgery

   Up and moving

   Most patients stand and walk with a walker within hours. Many go home the same day or the next morning with pain control, a blood-thinner plan and a therapy schedule.

2. Weeks 0–2

   Motion first

   Getting the knee straight and bending it steadily matters most. Therapy focuses on motion and walking, with ice and elevation to control swelling.

3. Weeks 2–6

   Build strength

   You move from walker to cane and then to walking on your own. Strengthening and balance work begin. Most people can return to desk work, and driving is generally allowed once off narcotic medicine and able to react safely.

4. Weeks 6–12

   Return to life

   Most daily activity feels normal. Cycling, swimming, walking and golf are usually resumed. Swelling and tightness can continue for several months.

Strength and comfort keep improving for up to a year. Call the office promptly for fever, increasing redness or drainage, calf pain or swelling, or a knee that suddenly cannot bend or bear weight.

Sources

1. Skou ST, Roos EM, Laursen MB, et al. A randomized, controlled trial of total knee replacement. N Engl J Med. 2015;373(17):1597-1606. Journal article
2. Evans JT, Walker RW, Evans JP, Blom AW, Sayers A, Whitehouse MR. How long does a knee replacement last? A systematic review and meta-analysis of case series and national registry reports with more than 15 years of follow-up. Lancet. 2019;393(10172):655-663. Journal article