What is Knee Arthroplasty?
Knee arthroplasty is a surgical procedure that involves the repair or reconstruction of a damaged knee joint to increase range of motion, relieve pain, and improve mobility. 1
Types of Knee Arthroplasty
Knee arthroplasty encompasses three main categories:
Total Knee Arthroplasty (TKA)
- TKA replaces both the medial and lateral femorotibial joints and the patellofemoral joint with an artificial prosthesis to restore function and relieve pain in patients with severely damaged knees. 2
- This is the most common type of knee replacement procedure, typically performed for patients with advanced osteoarthritis affecting multiple compartments of the knee. 3, 4
- The procedure uses various prosthesis designs including non-constrained (relying on patient's ligaments), semi-constrained (providing some stability), or constrained (for patients with ligamentous insufficiency). 4
Partial Knee Arthroplasty
- Partial knee replacement includes unicompartmental and patellofemoral replacements, which are performed when only one compartment of the knee is affected by arthritis. 3
- Unicompartmental knee replacement appears to be as effective as TKA for appropriately selected patients, with the advantages of shorter hospital stays and faster recovery times. 4
- These procedures offer more natural knee kinematics but carry higher revision rates compared to total knee replacement. 3
Revision Knee Arthroplasty
- Revision arthroplasty addresses failed knee implants using specialized components such as constrained condylar and hinged implants, stem extensions, augments, and megaprostheses. 3
- This procedure carries higher surgical complexity and complication risks compared to primary arthroplasty. 3
Primary Indications
The key indications for knee arthroplasty include:
- Radiological evidence of joint damage with moderate to severe persistent pain that is not adequately relieved by nonsurgical management (physiotherapy, analgesics, anti-inflammatory drugs, intra-articular injections). 4
- Clinically significant functional limitation resulting in diminished quality of life and substantial impact on daily activities. 4
- The most common underlying diagnosis is osteoarthritis, though post-traumatic arthritis and osteonecrosis with secondary arthritis are also indications. 5, 6
Clinical Outcomes
Knee arthroplasty is highly effective, with substantial evidence showing:
- Significant reduction in pain and improvement in function across all studies examining the procedure. 4
- Effect sizes and percent changes demonstrate effectiveness regardless of patient age, prosthesis type, or surgical technique used. 4
- The procedure relieves pain and improves knee function in people with advanced arthritis of the joint. 5
Common Complications
The most common risks associated with knee arthroplasty include:
- Deep venous thrombosis (prevented with heparin prophylaxis and compression stockings). 4
- Infection (minimized with 24-hour postoperative antibiotic prophylaxis). 4
- Stiffness (avoided by early mobilization in the days and weeks following surgery). 4
- Loosening and osteolysis (long-term complications). 4
- Revision rates ranging from 0% to 13% in studies with at least 5 years of follow-up. 4