Do I Need Knee Replacement Surgery?

Frank R. DiMaio, MD, MBA, Chairman, Musculoskeletal Service Line at Catholic Health and Orthopaedic Surgeon at St. Francis Hospital & Heart Center®, answers commonly asked questions about knee replacement surgery.

Q. What is knee replacement surgery?

During knee replacement surgery, an orthopedic surgeon removes damaged articular (surface) cartilage from the ends of the femur and tibia bones and replaces those ends with metal. The new “cartilage” includes a polymer “plastic” articular insert between the metal components. Frequently, the cartilage on the back surface of the patella or “knee cap” is also resurfaced.

Q. What conditions does knee replacement surgery treat?

Knee replacement surgery is recommended for patients with disabling arthritis that can no longer be managed with nonsurgical treatments.

Osteoarthritis is the most common form of arthritis. It is a degenerative disease that causes the cartilage surfaces to break down and wear away. Due to “wear and tear” over time, the joint no longer moves smoothly, and the bones may rub together, commonly referred to as “bone on bone.”

Osteoarthritis causes pain, swelling, stiffness, and changes to the joint alignment and mechanics. This results in limited mobility, such as difficulty walking, climbing stairs or getting up from a chair. Buckling or “giving out” of the knee is a common symptom.

Other common types of knee arthritis that may result in the above include traumatic arthritis after a previous injury, postsurgical arthritis after a failed previous operation, and rheumatoid type arthritis.

Q. Is knee replacement surgery right for me?

When arthritic knee pain becomes severe and affects the patient’s quality of life, it may be time to speak to an orthopedic surgeon about knee replacement surgery.

Knee replacement surgery is typically considered when all other nonsurgical options, such as anti-inflammatory medication, steroid injections, or viscosupplementation (gel injections), have failed. Modifying activities, bracing and physical therapy all help the patient manage their symptoms before surgery.

Q. What are the types of knee replacement surgeries?

After a comprehensive evaluation and careful examination with X-rays, your surgeon may recommend knee replacement surgery.

Most patients need a total knee replacement, which replaces bone and cartilage from the entire knee.

Other patients may need partial knee replacement surgery (uni-compartmental knee arthroplasty) when only one compartment of the knee is damaged. In this procedure, a portion of the knee is resurfaced and replaced with an artificial implant. The incisions are smaller than those for total knee replacement and recovery may be less difficult in some patients.

Revision joint replacement surgery is recommended for patients with a failed previous arthroplasty due to mechanical failure or loosening.

Many advances have been made in knee arthroplasty since the mid-1970s. Recent manufacturing improvements over the past 20 years have led to improved mechanics and longevity of implants. Improvements in surgical instrument platforms and robotic surgery will also play a role going forward.

Newer anesthetic techniques and pain management protocols have improved patient experience and shortened hospital stays. Many younger, healthier patients needing knee replacement surgery are eligible for ambulatory same-day surgery.

Q. How do you prepare for knee replacement surgery?

Your orthopedic surgeon will give you pre-surgical instructions that include:

Pre-op testing (such as a physical exam by your primary care physician)
How to prepare for your hospital stay (including arranging transportation post-surgery to your home or rehabilitation center)
Medications to stop taking (including those that can cause bleeding)

Q. What is the recovery time after knee replacement surgery?

Recovery time depends on your procedure. Partial knee replacement surgery does not require extended hospitalization. Some patients go home the same day, and everyday activities are resumed quickly.

Hospitalization for total knee placement is typically one to two days, and recovery will include an average of three months of physical therapy.

You will receive specific instructions for post-hospitalization, including:

How to reduce swelling
Medications you can take for pain
How to keep the area clean and dry
Avoiding driving or climbing stairs
Avoiding high-impact activities like sports and jogging
How to safely move around (including the use of an assisted device like a cane or walker)
How to safely bathe and use the toilet
How to look for signs of an infection (including fever, increased pain or redness, swelling or leakage around the incision area)

Q. How long does the procedure last?

Each surgery varies but usually takes one to two hours. General anesthesia is avoided in most surgeries. Instead, “paraxial anesthesia” or regional anesthesia, along with intravenous sedation, is most commonly used.

Q. Why is exercise recommended post-surgery?

Moving your new knee after surgery is important, so physical therapy begins in the hospital. A physical therapist will meet with you within hours to create an exercise plan, approved by your doctor, while you are in the hospital. Many patients walk within hours of their surgery. Pain is managed with oral narcotic and non-narcotic medications for your comfort.

Depending on the type of surgery, we will recommend home care for up to two weeks. Outpatient therapy is required until the knee has a restored range of motion, a steady gait, and regained function. Typical recovery time is within three months.

Once the recovery phase ends, you can engage in low-impact activities like walking, swimming and cycling. You can also resume daily activities like driving. But make sure you have clearance from your doctor and check in with them if you experience pain or discomfort.

Q. What are the risks of joint replacement surgery?

According to The American Academy of Orthopaedic Surgeons (AAOS), over 1.2 million people underwent total knee replacement surgery in 2023.

Joint replacement surgery is a common and safe procedure, but any surgery has some level of risk. New protocols have reduced the common risks of wound problems, post-surgical infection, and deep vein thrombosis (clots).

Q. How long does a knee replacement last?

Knee replacements typically last a lifetime. Barring a complication, patients older than 50 years of age can statistically expect their knee replacement to outlive them!

Keeping your body healthy, such as regular exercise and maintaining a healthy weight, reduces strain on the knees and keeps the implant durable. Healthy habits also benefit your overall health.