Do I Need a Partial or Total Knee Replacement?

Did you know that your knee is one of the most stressed joints in the body? In fact according to a recent study, one pound of weight exerted on your knee translates to four pounds of joint stress. When you consider this fact, it is no wonder that around 790,000 knee replacements are performed every year. You may even be considering a knee replacement yourself, especially if you are suffering from debilitating knee pain. 

Candidates for knee replacements are individuals who have severe arthritis or trauma that has damaged the knee joint. Oftentimes, people who need a knee replacement have a hard time walking and using stairs, while some even feel pain while sitting or lying down. Although there are non-surgical treatments for knee pain including medications and walking supports, people in need of a knee replacement often find little relief in these options. 

When considering knee replacement surgery, it is important to note that there are two different kinds: partial and complete. However, just because there are two different kinds does not necessarily mean that you can choose between the two. While there certainly are cases where you may have the option, oftentimes the condition of your knee will make the decision for you. 

In order to understand the difference between a partial and complete knee replacement, we must first understand some basic anatomy of the knee. The human knee is composed of three separate compartments. The compartment on the outside of the knee is known as the lateral compartment, the compartment on the middle or front of the knee is known as the patellofemoral compartment, and the compartment on the inside of the knee is known as the medial compartment. 

Since the knee is essentially separated into three compartments, this can mean that an injury or arthritis may only affect one compartment, while the other two may be just fine. In these cases, a partial knee replacement would generally be recommended. During a partial knee replacement, only the affected knee compartment (either the lateral or medial) would be replaced. Additionally, your anterior and posterior cruciate ligaments are preserved. However, the risk of having a partial knee replacement is that the other compartments of the knee may deteriorate over time and eventually require a total knee replacement.

Ideal candidates for a partial knee replacement are those that are: 

• Older than 60 years
• Less than 180 lbs
• Less active   
• Already has a good range of motion before surgery
• Has minimal deformity in the joint

In cases where two or more of the knee compartments are affected by arthritis or injury, a total knee replacement is usually recommended. Individuals who have rheumatoid arthritis are also recommended to have a total knee replacement, since this is an inflammatory type of arthritis.  During a total knee replacement, all three compartments of the knee are replaced with hardware. Additionally, a total knee replacement also requires the removal of your anterior and posterior cruciate ligaments. 

Ideal candidates for total knee replacement are those that have: 

• 2 or more compartments affected by arthritis or injury
• A deformity due to arthritis (bowing in or out)
• Rheumatoid arthritis
• Chronic knee inflammation or swelling that does improve with medications or rest
• Severe knee pain or stiffness that limits daily activities
• Tried other treatments like anti-inflammatory medications, cortisone or lubricating injections, or physical therapy with little to no improvement

Ultimately, to determine if a partial or total knee replacement is the best option, you will need to schedule an appointment with an orthopaedic surgeon. Only an orthopedic specialist can evaluate your individual case to determine whether a partial or total knee replacement is right for you.