Kellgren Stages of Knee Osteoarthritis: When to Use Hyaluronic Acid or Consider Surgery
Knee osteoarthritis (OA) is a progressive joint disease characterized by the breakdown of cartilage, leading to pain, stiffness, and reduced mobility. One of the most widely used systems to classify its severity is the Kellgren-Lawrence grading scale. Understanding these stages helps physicians and patients choose the most appropriate treatment, including non-surgical methods like hyaluronic acid injections or, in more advanced cases, surgical interventions.
The Kellgren-Lawrence (KL) scale is a radiographic grading system developed in the 1950s. It classifies knee osteoarthritis into five stages, from Grade 0 to Grade 4, based on visible changes in joint structure on X-rays.
Grade 0:
No signs of osteoarthritis. Normal joint structure.
Grade 1 (Doubtful OA):
Minimal osteophyte formation (bone spurs), no joint space narrowing.
Grade 2 (Mild OA):
Definite osteophytes, possible narrowing of the joint space.
Grade 3 (Moderate OA):
Moderate joint space narrowing, multiple osteophytes, possible bone deformities.
Grade 4 (Severe OA):
Severe joint space narrowing, large osteophytes, clear bone deformities, and sclerosis.
Hyaluronic acid (HA) injections are used to improve joint lubrication and shock absorption. They are most beneficial in the early to moderate stages of osteoarthritis.
Grade 1–2:
HA injections are typically effective in reducing pain and improving mobility. Patients at these stages can often delay the need for surgery with proper conservative management.
Grade 3:
HA injections may still offer temporary relief, especially for patients seeking to avoid or postpone surgery. However, their effectiveness may vary depending on cartilage loss and inflammation.
Grade 4:
HA injections are usually not recommended, as the joint damage is often too advanced. At this stage, surgical treatment such as total knee replacement is generally required.
Surgery becomes a valid option when conservative treatments no longer provide sufficient relief or when joint damage significantly impairs daily activities. In most cases, this corresponds with Kellgren Grade 4.
Common surgical interventions include:
Total knee arthroplasty (knee replacement)
Osteotomy (bone realignment in younger patients)
Arthroscopic debridement (rarely used in advanced OA)
The Kellgren-Lawrence grading system provides a clear framework for assessing the progression of knee osteoarthritis. In early to moderate stages (Grades 1–3), hyaluronic acid injections can be effective in relieving symptoms and maintaining joint function. In severe cases (Grade 4), surgical options should be considered for long-term relief.
Understanding where a patient falls on the Kellgren scale allows healthcare providers to recommend the most appropriate and effective treatment plan.
