﻿ FAQs for Knee | Smith & Nephew - US Patient

FAQs for Knee


For up to 20% of the patient population suffering from knee arthritis, minimally invasive partial knee replacement is a viable option. When only one compartment of your knee is damaged and your orthopaedic surgeon has determined that you have adequate ligament stability, the surgeon may choose to replace only the diseased portion of your knee. The healthy compartments remain untouched, and because the procedure is done through a much smaller incision than a total knee replacement, rehabilitation is less painful and more rapid.

Can I resume my normal activities after minimally invasive partial knee replacement?

Most patients can resume normal activities following partial knee replacement once they have regained adequate strength and flexibility and their orthopaedic surgeon has released them to begin normal activities. However, any activity that results in repetitive joint trauma, such as running, jumping or twisting, should be avoided. After recovering from partial knee replacement surgery, many patients have returned to activities such as swimming, golf, doubles tennis and gardening.

Why is an OXINIUM partial knee replacement something I should ask my surgeon about?

OXINIUM Oxidized Zirconium is nothing short of revolutionary. This new material is used to produce components of knee implants that offer superior performance characteristics over traditional cobalt chrome surfaces due to their increased hardness, smoothness and resistance to scratching and abrasion. OXINIUM material incorporates the best features of cobalt chrome without the risks often associated with it. This makes for potentially longer-lasting, superior performance.

How long will my partial knee implant last?

It's difficult to predict the lifespan of any individual knee implant. However, when good surgical technique and accurate instrumentation are combined with proper patient selection, the vast majority of patients remain trouble-free for up to and even beyond 10 years.

How do scratching and friction affect a knee implant?

Traditionally, cobalt chrome has been the material of choice for knee implants because of its strength and relative hardness. However, studies have shown that cobalt chrome implants have a tendency to roughen over time when implanted in the body. Thus, when a roughened replacement joint rubs against a plastic bearing surface, the plastic wears out. In fact, laboratory tests show that even a single scratch on a cobalt chrome surface can increase the rate of plastic wear 10 times. Over time, the plastic surface simply wears out and additional surgery is then needed to replace the worn implants. Studies conducted recently have proven through controlled wear testing that a scratched or roughened cobalt chrome implant will dramatically increase production of plastic wear debris and reduce the life span of the knee implant substantially.

So how long will an OXINIUM knee replacement last?

According to laboratory wear testing, OXINIUM implants demonstrate the scratch and wear resistance necessary to be potentially longer lasting as compared to traditional artificial knee joints. The smooth, hard surface of an OXINIUM ◊ implant is not a coating, but the result of a process which allows oxygen to absorb into the zirconium metal, which changes only the surface from metal to ceramic. The ceramic surface makes OXINIUM implants 4,900 times more abrasion resistant than cobalt chrome. It also reduces friction between the implant and the plastic surface for superior durability over time.

I am in pain, but my orthopaedic surgeon has advised me to wait for my knee replacement because I am too young. Why will an OXINIUM knee replacement be different?

Oftentimes in the past, orthopaedic surgeons have advised patients under 65 years of age to wait to have knee replacement surgery because the life span of traditional cobalt chrome implants is limited. With the new potentially longer-lasting OXINIUM ◊ knee implant, surgeons have a viable option for a younger patient who may not have been a knee replacement candidate in the past. Therefore, a younger patient with advanced arthritis no longer has to suffer for years until he or she reaches an appropriate age for joint replacement surgery.

In addition, patients who want to return to an active lifestyle which can include low impact activities like dancing, gardening and stationary cycling, may also benefit from OXINIUM ◊ knee replacements due to the fact that they are better able to tolerate activity and may last longer than traditional joint replacements.

What is OXINIUM and how is it made?

First, the zirconium alloy metal is shaped into an implant component. Secondly, the implant is put through a patented process which allows oxygen to absorb into the zirconium metal. Then, once the surface of the metal is saturated with oxygen, it changes from metal to ceramic. This ceramic surface gives the OXINIUM material significant advantages over cobalt chrome. And because only the surface is changed, the rest of the component is still metal and retains its overall strength.

Who is a candidate for total knee replacement?

If pain is preventing you from walking or performing daily activities and conservative measures have failed to give you adequate relief, it may be time to discuss total knee replacement surgery with your orthopaedic surgeon.

How old is the average patient for total knee replacement?

The average total knee replacement candidate is between 65-70 years of age. However, recent improvements in implant material and design now allow younger, more active patients to receive a knee replacement and achieve good long-term outcomes.

How long is the hospital stay for total knee replacement?

The normal hospital stay for total knee replacement surgery is three to five days. However, it's important to keep in mind that healing and recovery times vary from patient to patient.


Most patients are able to walk with the help of a cane within six weeks after surgery. You should also be able to drive a car within six to eight weeks after surgery. After fully recovering from total knee replacement surgery some restrictions may still apply. Normal, low-impact activities like walking, swimming, dancing, golf and bicycling are all appropriate. It is important to continue to work on your range of motion in the knee and to strengthen your hamstrings and quadriceps.

What about pain associated with total knee replacement surgery?

With today's advanced medications, you will be kept comfortable after surgery. And any temporary discomfort you may feel should not compare to the level of arthritis pain many people endure for months and years prior to having total knee replacement surgery.

What activities should I avoid after knee replacement surgery?

Namely, any activities that involve stopping and starting fast, twisting or high-impact loading activities like running, skiing or singles tennis. You should also avoid heavy lifting and repetitive bending and squatting.

Will my new knee replacement set off a metal detector?

It is unlikely that your implant will set off a metal detector. However, if it does, notify the security guard and they will pass a hand-held unit over the knee to verify.

