Introduction
The knee is the largest joint in the human body and one of the most vulnerable to injuries. Knee issues can arise from various factors, including injuries, aging, degeneration, and diseases like arthritis.
Arthritis leads to symptoms such as joint pain, stiffness, and swelling, which can severely impact the knee's cartilage. Cartilage is a resilient, shock-absorbing tissue that covers the ends of bones in the knee joint, facilitating smooth movement. As arthritis progresses, this cartilage can deteriorate, resulting in painful friction between the bones.
For many individuals, managing knee arthritis through medication and lifestyle changes becomes inadequate, making knee replacement surgery, or Knee Arthroplasty, a viable option. This procedure involves removing the damaged part of the knee and substituting it with artificial implants, or prosthetics. Knee Arthroplasty is among the most prevalent joint replacement surgeries, known for its effectiveness in alleviating pain and restoring function.
Anatomy
The knee joint is anatomically complex, composed of three primary bones: the femur (thighbone), tibia (larger leg bone), and patella (kneecap). The patella moves within a groove at the femur’s end. Ligaments—strong tissues connecting the knee bones—provide stability and enable movement. Large muscle groups in the thigh contribute to the strength and stability of the knee.
Two cartilage structures, known as menisci, sit atop the tibia. These menisci aid in shock absorption and allow for smooth movement. The knee joint is enclosed by a thin, smooth capsule lined with synovial membrane, which secretes synovial fluid. This fluid serves as a lubricant and cushion, ensuring that the joint functions smoothly and without pain.
Causes
Arthritis is the leading cause of knee pain, stiffness, and swelling, resulting from various factors, including aging, degeneration, injuries, and developmental issues within the knee. There are over 100 types of arthritis, with osteoarthritis, post-traumatic arthritis, and rheumatoid arthritis being the most common in the knee.
Osteoarthritis is the most prevalent form of arthritis, often developing with age. It can also stem from repetitive stress on the knee due to physical activities. This condition causes the cartilage covering the bone ends to gradually wear away, leading to painful bone-to-bone contact and impaired movement.
Rheumatoid Arthritis is a serious autoimmune disease that can affect individuals of any age, particularly women over 30. This condition inflames the synovial membrane, damaging cartilage and causing pain and stiffness.
Post-Traumatic Arthritis may occur at any age following a significant knee injury, such as fractures or ligament tears, which can lead to long-term cartilage damage.
Symptoms
Severe knee arthritis primarily manifests as moderate to intense pain, which can occur during both movement and rest, often disturbing sleep. Other symptoms include swelling, stiffness, and instability, making it difficult for the knee to remain straight.
Limited mobility may hinder daily activities like walking, climbing stairs, or rising from a seated position. When conservative treatments such as medication and physical therapy fail to provide relief, more aggressive interventions may be necessary.
Diagnosis
To diagnose arthritis, a healthcare provider will conduct a physical examination and review the patient’s medical history, symptoms, and pain levels. Simple movements may be performed to evaluate muscle strength, joint motion, and alignment.
Diagnostic imaging, such as X-rays, MRIs, or bone scans, may be utilized to assess bone health and identify areas of arthritis. These tests are painless and essential for determining the appropriate course of treatment.
Treatment
As arthritis worsens, conservative treatments—medication, rest, and physical therapy—may no longer alleviate symptoms. In such cases, knee replacement surgery becomes a recommended option for managing pain and restoring mobility.
Surgery
Knee Arthroplasty involves removing the damaged joint and replacing it with an artificial implant. This inpatient procedure usually requires a hospital stay of a few days. Patients may need to donate their blood beforehand for potential transfusions during or after surgery.
The surgery is typically performed under general anesthesia (which induces sleep) or spinal anesthesia (which numbs the lower body while keeping the patient awake). Your surgeon will guide you in selecting the best option.
During the procedure, the knee is positioned in a bent state, and an incision of approximately six to twelve inches is made beside the kneecap. The surgeon will displace the patella and thigh muscles to access the joint, removing the damaged bone and cartilage before implanting the artificial joint.
The artificial knee joint consists of three main components: a polished metal piece for the femur, a metal and plastic tibial component, and a plastic patellar part that fits within the kneecap. Depending on individual factors like age and activity level, the type of prosthetic used may vary. The new joint is designed to facilitate most of the pain-free movements you previously enjoyed.
Recovery
Post-operative recovery typically lasts two to three days in the hospital, during which pain management and strategies to prevent blood clots will be implemented. Patients may receive blood thinners and wear compression stockings. Elevating the leg and performing foot and ankle movements are crucial for recovery.
Physical therapy usually commences the day after surgery, focusing on walking and regaining strength. Initial mobility aids like walkers or crutches may be necessary, and therapists will assist in teaching how to navigate stairs safely.
An occupational therapist may also provide guidance on dressing and bathing with mobility restrictions in mind. In some cases, a short stay in a rehabilitation facility may be beneficial, where therapists can recommend home medical equipment, such as raised toilet seats or shower chairs, to enhance safety and independence during recovery.
Success after knee replacement largely depends on adhering to post-operative care guidelines. Many patients can return to most regular activities within three to six weeks and experience significant pain reduction, greatly improving their functional abilities.
