Osteoarthritis of the knee: An overview of treatments

by Judah Donaldson, APRN, FNP

Osteoarthritis (OA) of the knee is a degenerative joint disease characterized by the breakdown of cartilage, leading to pain, stiffness, and reduced function. It is a prevalent condition, especially among older adults, and significantly impacts quality of life.

While there is no cure for OA, various treatments aim to alleviate symptoms and improve joint function. Among these treatments, steroid injections and viscosupplementation with hyaluronic acid, have gained attention for their efficacy in managing knee osteoarthritis.

Understanding Knee Osteoarthritis

OA of the knee occurs when the cartilage that cushions the ends of the bones in the joint deteriorates over time. This degeneration results in pain, swelling, and difficulty moving the joint. Risk factors include age, obesity, joint injuries, repetitive stress on the knee, and genetic predisposition.

Treatment Approaches

The treatment of knee OA typically follows a tiered approach, beginning with non-pharmacologic measures and advancing to pharmacologic and surgical interventions when necessary. Common treatments include:

1. Lifestyle Modifications: Weight loss, exercise, and physical therapy can reduce stress on the knee joint and improve symptoms.
2. Medications: Analgesics (pain relievers), nonsteroidal anti-inflammatory drugs (NSAIDs), and topical treatments are commonly used to manage pain and inflammation.
3. Orthotics & Supportive Devices: Braces and orthotic inserts can provide additional support and reduce discomfort.

Steroid Injections

Steroid injections, specifically corticosteroids, are a common treatment for knee OA due to their potent anti-inflammatory properties. These injections can provide significant pain relief and reduce inflammation within the joint.

• Mechanism of Action: Corticosteroids inhibit inflammatory pathways by suppressing the production of pro-inflammatory cytokines (proteins that control inflammation) and enzymes. This leads to a reduction in inflammation and pain.
• Efficacy: Clinical studies indicate that corticosteroid injections can provide substantial pain relief for several weeks to months. However, the duration of relief varies among patients, and repeated injections may lead to diminishing returns.
• Procedure: The injection is typically administered directly into the knee joint under sterile conditions.
• Considerations & Risks: While effective, corticosteroid injections are not without risks. Potential side effects include joint infection, post-injection flare (transient increase in pain), and, with repeated use, possible joint damage and cartilage degradation.

Viscosupplementation with Hyaluronic Acid

Viscosupplementation involves the injection of hyaluronic acid into the knee joint to improve the quality of the synovial fluid, which lubricates and cushions the joint.

• Mechanism of Action: Hyaluronic acid is a natural component of synovial fluid. In OA, the concentration and molecular weight of hyaluronic acid decrease, reducing the fluid's lubricating properties. Viscosupplementation aims to restore these properties, thereby enhancing joint function and reducing pain.
• Efficacy: Research on viscosupplementation has shown mixed results. Some studies report significant improvements in pain and function, while others suggest only modest benefits. The effectiveness may depend on factors such as the severity of OA and individual patient characteristics.
• Procedure: Like steroid injections, hyaluronic acid is injected directly into the knee joint. The treatment typically involves a series of injections administered over several weeks.
• Considerations & Risks: Viscosupplementation is generally well-tolerated, with minimal side effects. Some patients may experience mild pain or swelling at the injection site. Rarely, there may be an allergic reaction to the injected substance.

Comparison & Conclusion

Both steroid injections and viscosupplementation are valuable tools in the management of knee OA, offering different mechanisms of action and benefits.

• Steroid Injections: Provide rapid and significant pain relief, particularly useful for acute flare-ups of knee pain. However, their long-term use is limited by potential side effects.
• Viscosupplementation: Offers a slower onset of action but can provide longer-term relief and improve joint function by enhancing the quality of synovial fluid. It is especially beneficial for patients with mild to moderate OA.

The choice between steroid injections and viscosupplementation should be individualized, taking into account the patient's symptoms, severity of OA, and overall health. Both treatments can be part of a comprehensive OA management plan, potentially used in conjunction with other non-pharmacologic and pharmacologic therapies to optimize patient outcomes.

As research continues, these treatments may be refined to offer even greater benefits to patients suffering from knee osteoarthritis.

Judah Donaldson is a family nurse practitioner who sees patients with orthopedic and spine conditions at the Paris Clinic and Terre Haute Specialty Clinic. He supports the practice of Dr. Harish Kempegowda, orthopedic and spine surgeon.