When your run has ran out...
Co Authored by Carlos M. Rodriguez, MD, Carlos Lavernia, MD, FAAOS and J. Pieter Hommen, MD
Eight questions you should ask the doc before knee replacement
Does your knee pain significantly limit your everyday life? Do you find yourself unable to perform even the easiest of household tasks? Have you been told you have knee arthritis? If so, then you might be an ideal candidate for a total knee replacement surgery.
Knee replacement surgery, or total knee arthroplasty, is one of the most successful surgical procedures performed today, rivaling corrective eye surgery and some plastic surgery procedures in terms of patient satisfaction. Nearly 700,000 knee replacements are performed each year in the United States alone.
- Am I a candidate for knee replacement?
Patients with advanced stages of arthritis of the knee are ideal candidates for knee replacement surgery. Prior to undergoing replacement surgery, the physician may recommend other conservative treatments such as weight loss, gentle exercise, knee injections, bracing, or therapy. When this conservative approach fails to improve the patient’s condition, then surgery might be the best next step. Age in patients with knee replacements ranges from teenagers with severe rheumatoid arthritis to ninety year olds with osteoarthritis, with the average age being approximately sixty-five years old.
- Who may not be a candidate for total knee replacement?
Patients with active infections should not undergo this procedure. Also those with higher risk for infection, such as patients who have diabetes or are immuno-compromised should take additional measures to prevent and/or treat infections if they arise. Patients with heart disease, neurological impairment, or peripheral vascular disease may need special medical clearance before surgery. Obesity is not a contraindication for surgery, but studies by Winiarsky et al. show that morbid obesity can be cause for increased risk for complications such as infections and impaired wound healing.
- When is the best time to have knee replacement surgery?
The exact time to undergo joint replacement varies from patient to patient. Delaying surgery may impact the amount of preoperative function and therefore functional outcome after surgery. As stated by Lavernia et al., different variables influence the decision to go through with surgery, but sometimes fear can cause a marked delay in surgical intervention, potentially leading to less favorable surgical outcomes. In studies performed at our institution, patients who seek joint replacement at an earlier age and earlier in the disease process tend to have higher patient satisfaction scores than those patients who sought medical treatment later in the disease process.
- What are the risks and benefits of total knee replacement?
The vast majority of patients experience marked improvements in pain and mobility without the misfortune of complications. These benefits include markedly improved mobility as well as the recovery of the natural leg alignment and the return to activities of daily living. However, as with any surgery, total knee replacement carries certain risks such as continued pain, stiffness, numbness, leg length discrepancy, loosening of the prosthesis, infection, blood clots, and death.
- What can I expect during and after the surgery?
imately forty minutes to two hours, depending on the degree of difficulty. Most procedures can be performed under a spinal anesthesia where the patient is anesthetized only from the hips down to the feet for the length of the procedure. An additional pain pump can be used to infuse local pain medication through a catheter along the femoral nerve to provide long-acting knee pain relief for two to three days after surgery. This modality presents a variety of added benefits to the patient after surgery. For example, the patient can expect less postoperative pain, earlier ambulation, and a shorter stay at the hospital.
The rehabilitation period after surgery varies from patient to patient. In general, the hospital stay lasts from three to seven days. During your stay, walking and range of motion exercises resume immediately after surgery to accelerate the recovery process as much as possible. Usually, regular activities of daily living can be resumed after three to six weeks postoperatively. Full recovery can be expected on most patients at up to twelve months after surgery.
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Arthritis is common reason for knee replacement
Arthritis is defined as inflammation of one or more joints, such as one or both knees or wrists, or a part of your spinal column. The most common type of arthritis is osteoarthritis, which is caused by over-use or wear and tear of the knee over time. It may be caused by excessive weight across the knee in obese patients or through repetitive high-stress knee activities like football. Another type of arthritis is rheumatoid arthritis, which may be a genetically acquired disease. Patients with this disorder suffer from cartilage destruction caused by the body’s over-reaction to its own cartilage. Those who are afflicted during their teenage years tend to demonstrate a more destructive disease than those who present later. Also, patients who have sustained a fracture or major ligament injury to the knee may develop another form of arthritis called post-traumatic arthritis.
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- What is minimally invasive total knee replacement?
The standard incision for knee replacement is eight to twelve inches long over the front of the knee. With advancements in knee surgery, small incision knee arthroplasty techniques have shortened the incision dramatically to four to six inches. The size of the incision largely depends on the amount of deformity at the knee, the obesity of the patient and if there was previous surgery performed. The incision must be large enough for the surgeon to safely and correctly perform the surgery without compromising the outcomes of the procedure. The potential benefits of small incision knee arthroplasty surgery are less postoperative pain, earlier ambulation, and a shorter stay at the hospital. Possible complications of small incision knee arthroplasty surgery include incorrect positioning of the implants potentially leading to earlier implant failure. Your physician will best determine if you are a candidate for small incision knee arthroplasty surgery.
- Knee replacement material
Currently, the metal used for total knee replacements is made of cobalt-chromium alloys or titanium alloys made for their durability. The metals are placed on the femur bone and the tibia bone and may be attached with polymethylmethacrylate bone cement or through non-cemented techniques. These include textured or porous coated implants to promote new bone growth into the surface. Allergies to the metals used are extremely rare; however, if you have a history of metal allergies, you should consult with your doctor. The plastic lining in between the two metals is made of a high-density polyethylene that is resistant to years of loading. Implants can last anywhere from ten to twenty-five years, primarily depending on the amount of cycles it is put through. In older more sedentary patients, they tend to last longer due to the lower amount of stress applied on a regular basis. For this reason, patients are usually advised to refrain from significant impact activity to the knee (e.g. jogging), especially in younger patients.
- What is removed from the knee during the surgery?
Diseased soft-tissue such as the cartilage, the menisci, and one or both of the cruciate ligaments are usually removed from the patient’s knee during surgery. The surgeon might spare the posterior cruciate ligament (PCL) in order to preserve the stability of the joint. According to Callahan et al., studies using posterior cruciate ligament-sparing prostheses reported higher mean postoperative global rating scale scores and fewer complications.
Unicondylar knee replacement
A lesser-known procedure, unicondylar knee replacement is designed to replace either the medial or lateral compartment of the knee. Because the incision needed is much smaller than with total knee replacement, the hospitalization is potentially shorter, the rehabilitation faster, and the return to normal activities more rapid. In spite of these benefits, only six to eight percent of patients with knee arthritis are good candidates for this type of knee replacement. Most patients have some degree of degenerative arthritic problems in other parts of the knee, which would need to be replaced simultaneously to prevent continued pain.
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