Queen's Medical Center POB1, 1380 Lusitana Street, Suite 808, Honolulu, HI 96813

Minimally Invasive Total Knee Replacement

Smaller incisions, Better Outcomes

What should I expect with my total knee?

There is no reason to sacrifice your lifestyle when it comes to your knee pain. We use our knees everyday when we we sit, stand, or play with our children. Sometimes, our knees wear out due to injury, illness or the normal aging process. When your knees become worn, your everyday movements can be painful and difficult.

You do not have to live with your aching knees. A knee replacement can help you maintain your quality of life. If your life is limited because of knee pain, you may be a candidate for a knee replacement surgery.

Knee Pain


Am I a Candidate for Total Knee Surgery?


Total Knee Replacement


Realistic Expectations

Frequently Asked Questions

Schedule Appointment

Am I a candidate for Knee Replacement surgery?

When you have failed non-operative treatment for arthritis, you should consider a knee replacement. Non-operative treatment includes injections, anti-inflammatory medications, or exercise.
The goal of a knee replacement surgery is to alleviate your pain and improve function. The best time to think about surgery is when you are having difficulty with the following scenarios:

  • Your daily living activities: household chores and grocery shopping
  • Leisure activities: golf, gardening, long walks, bike riding
  • Loss of ability to work due to pain
  • Avoidance of seeing friends or family
Knee Replacement Model


I will make the diagnosis of arthritis through history and physical exam. An x-ray will be performed in the clinic. The x-rays in someone with arthritis typically show cartilage loss and bone spur growth. The common term we use to describe arthritis is“bone-on-bone.” This term refers to the damage and loss of cartilage between your thigh and shin bones. Bone-on-bone arthritis occurs when you have severe arthritis.

Total knee Replacement

A total knee replacement is a surgery that removes the damaged parts of your knee, which is replaced with an artificial joint. Your new knee is composed of metal and plastic. During the surgery, the metal is solidly fixed to the end of your thigh bone and your shin bone. Your knee replacement is made of a highly-engineered plastic, called polyethylene, that is inserted between the two pieces of metal. The kneecap is also replaced with a small plastic button. I may also consider you a candidate for a partial knee replacement, and will discuss this during your visit.


What's the Recovery Like for a Total Knee?

As the operation is over, you will use your new knee. Most patients begin to walk on the day of surgery with the help of a physical therapist. Your physical therapist will show you how to walk again with a walker as you are recovering. As your muscles heal, you will have some pain. During the first couple of weeks your pain and motion will improve. Over time, you will regain your strength.  Pain after a knee replacement usually resolve over the next few weeks to months. We will provide you with pain medication after surgery and monitor you, making sure that you are comfortable.

What are my goals after surgery?

Six weeks after surgery, most patients with sedentary jobs may return to work. Often, patients are able to walk comfortably by 3 months. Full recovery usually occurs at one year, but may take up to 2 years to have all of your aches and pains improve after knee replacement

Knee replacements are designed to allow you to enjoy many activities such as long walks, dance, playing golf, gardening, and riding a bicycle. Knee replacements have an excellent track record for improving your quality of life, reducing your pain, and providing independence.

total knee replacement

Realistic Expectations

When you are deciding to have a total knee replacement, you must understand the limitations to what the implant can do. Most people who have a total knee replacement have a dramatic reduction in their knee pain and an significant improvement in the ability to perform every day activities. However, with normal activities, you will slowly wear the plastic piece in your knee replacement. The wear and tear can be sped up with excessive activity or weight. Damage to the plastic piece will cause the knee replacement to loosen or become painful. I agree with the American Academy of Orthopedic Surgeons and the American Association of Hip And Knee Surgeons in advising my patients to avoid running, jogging, jumping or other high-impact activities with a knee replacement.


We have high success rates with our knee replacements. However, a knee replacement is a major surgery. There are many possible risks associated with your surgery including:

  • Blood clots
  • Blood loss
  • Infection
  • Implant loosening
  • Fracture
  • Knee stiffness
  • Nerve or blood vessel damage

Dr. Morton does his best to limit the complications of surgery. To learn about improvements in this area, talk with him about robotic joint replacement surgery.

Frequently Asked Questions About Knee Replacement (FAQ)

How long does a knee replacement last?

Modern knee replacements have made a drastic improvement with the invention of highly cross-linked polyethylene. Polyethylene is the plastic component within your knee replacement. Traditionally, these plastic components are expected to last up to 20 years in 90% of people. With newer plastic components, we are hopeful that knee replacements will last even longer.

There are newer knee components including those made from Vitamin E or ceramic, which may reduce the wear of the plastic component.

This length of time that a knee replacement will last is variable. While the current generation of knee implants are expected to last most of our patient's lifetimes. Orthopedic surgeons worry that high levels of activity, weight, or other complications such as infection or loosening could lead to the need for revision.

Am I too young for a knee replacement surgery?

Traditionally, knee replacements were reserved for patients who were elderly with severe knee arthritis. Concerns regarding patients who undergo knee replacement at a younger age are focused on the wear of the knee replacement components. Any patient who is in their 40's and 50's is considered "young" for a knee replacement. However, they may still be a candidate for a knee replacement if they understand the limitations of the implant and have failed non-operative treatment.

The average age of patients today undergoing a knee replacement is 65 years old. While patients under the age of 50 are the fastest-growing segment of the population undergoing knee replacement surgery, many orthopedic surgeons have reservations.

Can I run or jog after a knee replacement? What kinds of sports activities can I be involved in?

Running can put a tremendous amount of stress across your new implant. I would be very careful before starting a heavy-exercise program on your new knee replacement. Despite this, you can still be an athlete and do certain types of activities. The American Academy of Orthopaedic Surgeons (AAOS) recommends the following activities with a total knee:
- Bicycling
- Calesthetics
- Swimming
- Low-resistance rowing
- Gentle Skiing
- Walking & Hiking
- Low-resistance weightlifting

Similarly, the AAOS advises against high-impact activities:
- Baseball
- Basketball
- Football
- Hockey
- Soccer
- High-impact aerobics
- Gymnastics
- Running and Jogging
- Powerlifting

Should I lose weight before knee replacement surgery?

Even if you feel fit and healthy, you may be asked to lose weight before knee replacement surgery if you are heavier. Much of the research on complications following knee replacement surgery has been focused on patients with a high body mass index (BMI). In fact, Queen's Medical Center will not allow the scheduling of any surgery of patients with a BMI greater than 40. This is because patients who are heavier are at higher risk for the following complications:
- Infection
- Component loosening
- Poor wound healing
- Blood clots
- Pulmonary embolism (blood clot travels to the lung)

Typically, we ask patients to aim for a BMI that is less than 40 prior to surgery. We would prefer patients to obtain a BMI less than 35 as this will significantly lower your risk profile.

Should I have bariatric surgery before my knee replacement?

Some patients find that once they lose a significant amount of weight after bariatric surgery, they do not need to see an orthopedic surgeon for a knee replacement. If you are able to successfully lose enough weight before surgery, you may also reduce the chance of a complication after your surgery. Obtaining a healthy weight should be your goal.

Should I quit smoking before my joint replacement?

Tobacco use is known to be a significant risk factor for loosening, infection, or wound healing problems. Minimizing your tobacco use or quitting before surgery will make a significant impact. If you are able to quit for life, you will significantly reduce your risk of other complications to your overall health as well. Learn more about tobacco effects on joint replacements here.

Do I need to get my bad teeth fixed before surgery?

Infections in your mouth are a significant risk factor for a knee replacement infection. We recommend that any evidence of a dental or gingival infection be addressed prior to surgery. Some clinics even require mandatory dental clearance prior to surgery. After surgery, we will often provide patients with antibiotics prior to deep cleaning or any major dental work.

When can I go to the dentist after my knee replacement?

I usually recommend that people wait three months prior to having any dental work done. Please ask for antibiotics, especially within the first year of your surgery.

Should I have a partial (uni) or total knee replacement?

Partial and total knee replacement surgery have excellent track records. There are risks and benefits to both operations. Partial knee replacements often leave patients with a more "natural feeling" knee, while total knee replacements are able to provide the longest term result with lower risk of re-operation.

Is it necessary to have a robot assist with the surgery?

Robotic joint replacements are a hot-topic in hip and knee replacements. While you may not need a robot to perform your surgery, robotic knee replacements are able to provide a much more accurate positioning of your knee replacements and personalize the implantation to your anatomy. Much like anterior hip replacements are able to position our implants better and improve outcomes, I believe that robotic joint replacements can make the same improvements for knee replacements.

Should I have my knee replaced before my hip?

It is often difficult to determine if your knee pain is secondary to your hip arthritis. A careful examination of your hip and knees will help determine what is the source of your pain. If the arthritis is similar in both your hip and knee, often replacing the hip will provide you with improved pain relief that you may not need a knee replacement.

How close before surgery can I have an injection in my knee?

While the science is conflicting on whether injections are associated with infected knee replacements, many insurance companies have made limitations on joint replacements after injections. If you have an injection, most insurance companies will not support payment for a knee replacement for 3 months after your injection. This is with the health of our patients in mind. Avoidance of an infection is of utmost importance as an infection can have devastating consequences.

Do I need custom implants for my joint replacement?

Custom implants and customized jigs are a technology that has not demonstrated to have brought significant value for patient outcomes. These devices have not been demonstrated to be more reliable than traditional knee replacements. It is likely because it does not take into account your soft-tissue anatomy at the time of surgery. This is the difference that robotic joint replacements provide.

How long will the operation take?

Time is relative. For patients undergoing a knee replacement - it will be as if no time has passed, as they will be asleep. For family members in the waiting room, it can be a couple of hours before they have a chance to see their loved ones, depending on the anesthesia used. For me, it usually takes between 30 minutes to an hour to perform a knee replacement depending on patient anatomy. This is because I perform all parts of the operation, including exposure, implantation, and closure.

Do I need to go to a skilled nursing facility or rehab after knee replacement?

Modern knee replacements are performed on an outpatient basis. Many patients are able to go home on the same day, and sometimes the following day. This is because our pain control and anesthesia have significantly improved. Some patients who do not have adequate support at home will require a skilled nursing facility to recover until they are strong.

How long will I stay in the hospital after my knee replacement?

All patients undergoing a partial knee replacement are able to go home on the same day. We evaluate every patient who undergoes a total knee replacement to see if they should stay in the hospital for monitoring. Usually patients are able to go home by the next day. Some patients will require a longer hospital stay if they have medical complications or comorbidities. Even some revision knee replacements are able to leave the next day as well.

When can I drive after a knee replacement?

This depends on if you drive a manual transmission car, and if your replacement involves your right or left knee. Patients who undergo a right knee replacement are going to take longer to start driving - sometimes up to 6 weeks.

I allow patients to drive when they reach the following goals: 1. No significant pain while driving, 2. No longer taking narcotics, 3. Able to stop in the event of an emergency such as a small child crossing the road.

Most patients are able to achieve this with a left knee replacement around two-weeks after surgery.

How quickly will I be up after a knee replacement?

We have our patients walking the same day. patients who are expected to go home will have a course of physical therapy in the post-op unit to ensure that they are safe to go home.

When can I return to work after surgery?

This is a complex question depending on what job type you are doing.

Desk job: I tell most patients that they will feel well enough to begin working around two-weeks after surgery. Some patients who are hung-ho will even start working immediately after surgery.

Light Labor: Light labor that requires frequent walking or light lifting. Some patients may require 6 weeks to 3 months before returning to work. Close monitoring will be needed to help you determine when you are safe.

Heavy labor: Construction and other types of manual labor usually requires at least 3 months of recovery. Some patients will have to change their career depending on their demands. Talk with your surgeon before returning to work.

I have numbness on the outside of my knee after my replacement. Is this normal?

During a knee replacement, we cut through the infra-patellar branch of the saphenous nerve. This nerve is responsible for the sensation on the outside of your knee. This usually disappears slightly with time, but you will always have a numb area there. Some patients can develop a painful neuroma. I am happy to talk about any of your concerns about this numbness.

My friend got a Continuous Passive Motion (CPM) machine after surgery. Why didn't I get one?

These devices have fallen out of favor in the orthopedic community. We have found that these devices are expensive and have not made a difference in return to motion after a knee replacement. These have not been used for years by most orthopedic surgeons.

Is bruising normal after knee replacement?

Yes. In order to implant your new knee, we have to move the muscles and soft tissue to the side. Cutting the bone can cause a significant amount of blood flow. This will cause a large amount of bruising and discoloration after surgery.

Is blistering around my incision normal after knee replacement?

Blistering can be a side effect of the bandages or swelling after your replacement. Blistering is a rare phenomenon. If you have blistering, please call me to make sure that there are no complications to be concerned about.

Do I need a card when I go to the airport? Will I set off the metal detectors?

You do not need a card after your new knee replacement. After all, if you were a terrorist - they would still have to scan you. They will still let you fly, even if you don't have a card. You will have to let the TSA agent know that you have a metal implant in your knee.

Related Pages

Minimally Invasive Total Knee Replacement - Smaller incisions, Better Outcomes 1
Rosa Robotic Surgery at Queen's Medical Center
ROSA is a robotic platform that takes a personalized approach to planning for your knee replacement using a three-dimensional model Read more
Knee Pain in elderly woman
Knee replacements are life-changing. The ability to be more active without pain provides a better quality of life which can Read more
Dressings shower
Wound healing begins before surgery Better wound healing begins with preoperative optimization for surgery.  Risks for developing complications include smoking, Read more
Minimally Invasive Total Knee Replacement
Sports after a total Knee Replacement Many patients ask about return to sports after a total knee replacement. Total knee Read more
partial vs total knee replacement
What is a knee arthroplasty? Knee arthroplasty is an excellent treatment for knee arthritis.  Knee arthritis occurs as the smooth Read more
Outpatient Total Knee
Traditional Total Knee Replacement Total knee replacement is the surgical treatment for knee arthritis.  Surgeons remove the damaged portion of Read more

Schedule an Appointment

Meet Dr. Paul N. Morton, MD

Dr. Paul N. Morton, MD is a fellowship-trained orthopedic surgeon in hip and knee surgery, specializing in robotic joint replacements, complex joint reconstruction, sports injuries, and trauma. Reach out to him to learn more about treatment options for your problem.

Written By: Dr. Paul N. Morton, MD


Post Published on October 17, 2018