Partial Knee Replacement


Understanding Your Options

Many patients who have knee arthritis have disease in only a portion of their knee joint. The rest of the knee is oftentimes completely normal. Partial knee replacement involves replacing only the diseased part of the knee. This allows for the preservation of your normal cartilage and normal ligaments in the rest of your knee. By doing this, your knee is able to move more normally and feel more like your own knee. This surgery is easier to recover from than a full knee replacement and will provide just as much pain relief if done on the correct patient.

Nonsurgical Management

Before having surgery, many patients will try conservative measures. Anti-inflammatory medications like Aleve or ibuprofen can give some relief. There are also prescription anti-inflammatories that may be prescribed. Knee injections using a steroid, such as cortisone, may be utilized to give more focused pain relief. These injections may be less helpful in more severe arthritis. Lastly, physical therapy can be used to strengthen the muscles around the knee to offload the stress the knee is feeling. Weight loss can be one of the most effective treatment options.

Preoperative Testing

Before having surgery, you will be seen by your primary care provider or another doctor arranged by our office to help ensure that you can safely undergo surgery. Testing will often involve an EKG and basic lab work as well as a comprehensive history and physical exam to ensure that you do not have any major medical issues that would make it more difficult to undergo surgery.


The surgery itself takes less than an hour. The time spent in the operating room is close to two hours. Partial knee replacement involves a smaller incision on the front of the knee that is about three to five inches long. The rest of your knee is checked at the time of surgery to ensure that there isn’t any arthritis in other parts of your knee as well.

You Are Going to Replace Only Part of My Knee?

That’s right! By leaving the rest of your knee alone, we are able to preserve the natural ligaments and cartilage that allow your knee to move more normally. This allows for a quicker recovery and for you to be able to return to more advanced activities easily. Surgeons used to incorrectly consider the partial knee replacement as a stepping stone to a full knee replacement. What we have found is that the risk of needing additional surgery on a partial knee in a well-selected patient is not much different than for someone having a total knee replacement. If you are young and do have progression of your arthritis over decades of using your partial knee replacement, the conversion to a total knee replacement is an easier operation, and the hope is that we have given you many years of a highly functional partial knee replacement while you are young and active.


Implants that are used today are typically made of titanium coated in a shiny metal called cobalt chromium. The articulating surface of your knee is a highly durable plastic. The implant is typically cemented to the bone so that it is strong enough to be able to walk on from the moment you leave the operating room. Patients often want to know how long their knee implants will last. Unfortunately, we don’t know the answer yet. Around 1999, we made a pretty significant change to the plastic used. Prior to that time, the implants were lasting between 15 – 20 years. Implants that have been in for almost 20 years now have shown very little wear at all. We can confidently say the implants will last 20 years. It is very likely that they will last 30 years or more, but we will closely watch the implants to track their durability over time.


Most patients will have a spinal and epidural anesthetic as well as a nerve block. This involves having numbing medicine placed by an anesthesiologist that will give you complete pain relief in your lower extremities. This is helpful because you will not require a breathing tube and you will not require narcotics and other medications during surgery that can make you drowsy for a long time. Don’t worry—you will be given some lighter medications to allow you to comfortably take a nap and not be aware of all of the commotion of the operating room (similar to medications that they give during a colonoscopy).

Postoperative Expectations

Most patients are able to go home the same day as their surgery. This rapid recovery is one of the biggest advantages of a partial knee replacement. In rare instances, patients with complicated medical problems will spend a night in the hospital. Having a good team at home to help you with recovery is important.

Most patients will use a walker for a week or two as they get more comfortable walking on their new knee. You will transition to a cane or crutch for a week or two. By the time you come to your first appointment, you may be using your cane for longer walks but you may not be using it much at all. Physical therapy is arranged; although, most patients don’t need much therapy. Walking is the best exercise after knee replacement, and your range of motion will improve quickly.

Recovery after joint replacement takes a full year; however, 90% of your recovery will happen in the first three to four months. When you are fully recovered from your knee replacement, there will be no restrictions on your activity and you can resume any and all activities that you wish.


All surgeries have possible complications. These complications are rare, and we will do everything to help ensure they don’t happen to you. Below are some of the more significant complications that can occur.

  • Infection

    Infections in joint replacements are catastrophic problems. They often require multiple surgeries and weeks of IV antibiotics to get rid of it. This is why it is very important to make sure that you are healthy before surgery and take good care of your incision after surgery. The overall risk of an infection is less than 0.5%.

  • Blood Clots

    Major surgery on the lower extremity puts you at risk for blood clots. The risk of blood clots is higher in some patients, particularly those who have a clotting disorder or a history of blood clots in the past. We will put you on a blood thinner for a month after surgery. Based on your risk factors, it may be as little as just an aspirin twice per day or it may be something stronger. Being as mobile as you can after surgery will help reduce this risk.

  • Nerve or Vascular Injury

    Any time you have surgery, the surgeon does everything possible to avoid damaging nerves and blood vessels that are near the surgical site. One small skin nerve that gives sensation to the outside part of your knee is often unavoidably stretched during surgery. Many patients after knee replacement will have a small area on their outer knee area which is numb. Over the course of a year, that numb spot gets very small and is often not noticeable or bothersome, as it is not in a part of your body that is very sensitive.

If you have any questions regarding partial knee replacement or if you would like to schedule an appointment with Dr. Blake Peterson or Dr. Corey A. Trease please call (816) 233-9888 or click on the Appointment Request button.

Orthopedic and Sports Medicine Center
3107 Frederick Ave, Suite B
St. Joseph, MO 64506
Phone: 816-368-9652
Fax: 816-233-0414
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