Introduction
Knee replacement surgery is the most prevalent type of joint replacement procedure. The knee joint is particularly vulnerable to injury, and various factors such as trauma, aging, wear and tear, and arthritis can lead to knee issues.
Arthritis is a condition that results in joint discomfort, stiffness, and swelling, significantly affecting the cartilage within the knee joint. Cartilage is a resilient, shock-absorbing tissue that covers the ends of bones, providing a smooth surface that facilitates movement. When arthritis progresses, this protective cartilage can deteriorate, leading to painful friction between the bones.
For many individuals, managing knee arthritis with medications and lifestyle changes becomes insufficient. Knee replacement surgery often becomes necessary to alleviate pain, restore functionality, and enhance quality of life. One option is Minimally Invasive Knee Arthroplasty, which, like traditional knee replacement, involves excising the damaged knee portion and replacing it with prosthetic implants. The key difference is that this approach uses smaller incisions, resulting in reduced pain, shorter hospital stays, and quicker recovery.
Anatomy
The knee is the largest and most intricate joint in the body, consisting of three main bones: the femur (thighbone), which rests on the tibia (larger leg bone), and the patella (kneecap) that moves within a groove at the femur's end.
Strong ligaments connect these bones, providing stability and facilitating movement, while the thigh's major muscle groups support the knee. Additionally, two menisci (cartilage discs) sit atop the tibia, enabling smooth motion and acting as shock absorbers during activities like walking and running.
A thin tissue capsule envelops the knee bones, lined with the synovial membrane, which secretes synovial fluid. This fluid serves as both lubricant and cushion, promoting smooth, pain-free movement.
Causes
Arthritis stands as the leading cause of knee pain, stiffness, and swelling, arising from various factors including aging, injuries, diseases, and structural abnormalities. There are over 100 forms of arthritis, with osteoarthritis, post-traumatic arthritis, and rheumatoid arthritis being the most common in the knee.
Osteoarthritis, affecting around 21 million Americans, typically develops with age or due to excessive use, causing the cartilage to wear away and resulting in painful bone-on-bone friction.
Rheumatoid arthritis, a severe autoimmune condition, can affect individuals of any age, particularly women over 30. This long-term condition inflames the synovial membrane, damaging cartilage and leading to pain and stiffness.
Post-traumatic arthritis can occur at any age following a serious knee injury, such as fractures or torn ligaments, which may lead to cartilage damage and subsequent pain.
Symptoms
The primary symptom of advanced knee arthritis is pain, which can manifest during movement or at rest and may disrupt sleep. Individuals may experience swelling, stiffness, and instability, leading to visible misalignment of the knee.
Difficulty in bending or moving the knee can severely impact daily activities such as walking, climbing stairs, or getting in and out of chairs. While medications, rest, and physical therapy may alleviate some discomfort, they might not be sufficient for severe cases.
Diagnosis
Diagnosing arthritis typically begins with a physical examination where the physician evaluates medical history, symptoms, and pain levels. Patients may be asked to perform basic movements to assess strength and alignment.
Diagnostic imaging, including X-rays, MRI scans, and sometimes bone scans, helps visualize the extent of damage and identify arthritis. X-rays reveal bone conditions, while MRIs provide detailed images of surrounding tissues. Bone scans, requiring a harmless radioactive injection, pinpoint areas of abnormal bone activity.
Treatment
As arthritis worsens, non-surgical methods like medications, rest, and physical therapy may become ineffective. When symptoms persist and significantly hinder daily activities, knee replacement surgery may be recommended, particularly minimally invasive procedures that offer faster recovery and less bodily trauma.
Surgery
Minimally Invasive Knee Arthroplasty presents a viable alternative to traditional knee replacement for certain patients. While both methods involve replacing the damaged joint with an artificial one, the minimally invasive approach utilizes smaller incisions (3 to 6 inches compared to the traditional 8 to 12 inches), resulting in shorter hospital stays, easier recovery, and smaller scars.
Typically performed as an inpatient procedure, anesthesia options include general anesthesia, which induces sleep, or spinal anesthesia, which numbs the lower body while the patient remains awake but sedated.
During surgery, the knee is positioned for optimal access. The surgeon makes a small incision, carefully moves the patella and thigh muscles aside, and removes the damaged bone, cartilage, and tissue. The artificial joint consists of three main components: a polished metal femoral piece, a metal and plastic tibial component, and a plastic patellar part, which can be cemented or implanted, facilitating pain-free movement.
Recovery
Post-surgery, patients may remain in the hospital for a few days, during which they receive pain management and preventive measures against blood clots and swelling. Blood thinners, support stockings, and leg elevation are common strategies.
Early mobility is crucial for recovery, often beginning the day after surgery with physical therapy. Patients may initially require walkers or crutches, with therapists guiding them through exercises to enhance strength and functionality.
Occupational therapy may assist with daily activities, recommending home adaptations to ensure safety and ease during recovery. Success hinges on adherence to home care instructions and regular activity, with most individuals resuming regular functions within three to six weeks after surgery.
Continuous exercise and safety precautions are vital, including fall prevention strategies and proper use of recommended medical equipment.
