Short Total Joint Summary
By Barry Waldman, MD, Director of the Center for Joint Preservation and Replacement at Sinai Hospital
Osteoarthritis is a very common cause of hip and knee pain. It is the result of the gradual wear and tear of the cartilage, which lines the joint. As the cartilage wears away, the bones begin to rub together causing pain.
Doctors treat the pain with conservative methods, such as over the counter medications, prescription medications, heat and ice, bracing, and topical medications to provide pain relief. However, sometimes these measures no longer help control the pain, and surgery becomes necessary.
Thanks to advances in the surgical treatment of joint pain, there are a variety of long lasting solutions, which can free you from nagging joint pain. Learning about these options may help empower you to take charge of your life again.
There are many options now available to replace the knee joint. They include the traditional total knee replacement, and more conservative implants that preserve more of the natural knee. These implants, such as the Uni-knee or UniSpacerTM are intended to replace only the worn out area of cartilage, leaving the rest of the knee intact. Most people are familiar with total knee replacement but little information is available concerning these bone preserving, minimally invasive techniques.
When a patient exhibits arthritis on only one side of their knee, a procedure called unicompartmental knee replacement can relieve pain and improve function without the need to replace the entire knee joint. Therefore, only patients who exhibit cartilage lose or damage on the inside of the knee joint may be candidates for this implant. In comparison, the uni-knee replacement is not limited to only one side but can be used to replace either the inside or outside of the knee joint.
Here are a number of advantages to the Uni-Knee procedure over the traditional total knee replacement:
Smaller Incision - Before the procedure, the entire knee is examined with an arthroscope through a very small incision. If the rest of the knee is relatively intact, a 3-inch incision is made. A traditional knee replacement requires an 8-inch incision.
Less Blood Loss - The minimally invasive nature of the procedure generally eliminates the need for a blood transfusion. Total knee replacement often requires transfusion or preoperative donation of blood.
Easier Rehabilitation - Since the incision is smaller and the knee cap is not turned upside down as it is during a total knee replacement, moving and bending the knee after the surgery is much easier.
Shorter Recovery - Most patients are driving a car and resuming their normal daily activities two weeks after the surgery. With a total knee replacement, recovery time can much longer and require more extensive physical therapy.
Less Bone Removed - Much less bone is removed than during a standard knee replacement and even less than other forms of unicompartmental knee replacement. If a total knee replacement is needed in the future, enough bone remains to perform the surgery without added difficulty.
Who Can Benefit From Unicompartmental Knee Replacement? Persons 50 and older who show one or more of the following symptoms may benefit from this procedure:
• Pain while standing
• Pain while walking short distances
• Pain changing position, such as sitting to standing
• Persistent knee swelling
• Giving out or locking of the knee.
• Failure of the knee to respond to medical treatment
Knee X-rays, taken while standing, can indicate if the uni procedure may be appropriate. The X-ray must show complete loss of the joint cartilage in one of the two weight-bearing compartments, as demonstrated below.
Minimally invasive knee replacement
Minimally invasive techniques can also be applied to total knee replacement resulting in a smaller incision, less muscle damage and faster recovery. The procedure can be performed without cutting the quadaceps tendon, which can speed recovery and reduce pain.
Over the past few decades, many advances in hip replacement have been made and several types of prostheses are available. They may include the traditional total hip replacement, which is a combination of metal and plastic, and the newer metal on metal total hip replacements.
What is the difference? A traditional total hip replacement uses a metal ball of 28 millimeters in diameter and a plastic socket for motion. While it has an excellent record for long life and durability, the plastic wears with each step and can lead to eventual loosening of the hip replacement. This process can take 10 to 20 years and is not a problem for most patients.
The metal on metal total hip simply replaces the plastic material with metal, which is either a cobalt-chrome alloy, or a titanium alloy. These are "super metals" initially developed for the aerospace industry and now adapted for orthopedics. In laboratory simulations, the wear rate of metal-on-metal is as much as 1000 times lower that traditional metal on plastic. While metal-on-metal does not have the proven track record of metal on plastic, it is believed that it has the potential to last much longer than traditional hip replacements. This procedure has been used successfully for the last two years with excellent early results.
Larger 38 Millimeter Hip
Dr. Waldman has been using a larger metal-on-metal ball, which measures 38 millimeters compared to the traditional 28 millimeters ball, for the past 4 years. This larger ball has a number of advantages including a lower chance of dislocation. It can be performed using minimally invasive techniques through a much smaller incision and the result is less muscle disruption. Patients with the new ball size also have greater range-of-motion and report a more "natural" feeling to the hip.
Though the 38 millimeter prosthesis is FDA approved, the procedure is new and the long-term record isn't known yet. For this reason, surgeons at Sinai are involved in a 5 year follow up study to record and provide to the public proven research on the longevity of this prosthesis and procedure.
The type of prosthesis used for your knee or hip surgery is determined by the surgeon and is based on a number of factors such as your height, weight, age, and bony structure. When considering surgery, ask your doctor about your options.
Magnum Hip
The newest improvement in metal-on-metal hip replacement is the Mangum, or very large head hip. This prosthesis uses a thin but strong metal cup with a head only 6 mm smaller than the cup. This allows maximum range of motion and full activity with the largest head possible for each patient. It is appropriate for younger patients.
Minimally invasive hip replacement
Dr. Waldman has developed a procedure for performing any of these procedures through a single small incision, often only 3 inches in length. This technique has been proven safer and more reliable than 2 incision techniques. It can also be performed in larger patients without undue difficulty.
For more information regarding the procedures described above, please contact Dr. Waldman at 410-377-8900 or by email at bwaldman@mdorthoteam.com.
