Is Vitamin D the Magic Pill for Knee Arthritis?

Knee pain
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Osteoarthritis (OA) of the knee is a difficult problem that affects millions of people world-wide. Over percent of men and women over 60 are effected by knee osteoarthritis. Non-steroidal anti-inflammatory medications (NSAIDs) such as ibuprofen (Advil) or naproxen (Aleve), as well as activity modification have been the most common methods of conservative treatment.

Unfortunately the use of NSAIDs is not without its risks.

NSAIDs can lead to serious stomach-related issues including bleed ulcers and kidney damage. Because knee OA is such a prevalent issue that limits the productivity of people around the world, the medical and healthcare communities have been on a mission to find a non-operative intervention that can solve, or at least improve, the issue of OA.

Treatment of Knee Arthritis 

There have been many forays into possible magic pills and injections, to help alleviate the symptoms of osteoarthritis. These have included glucosamine and chondroitin supplements intended to rebuild cartilage, as well as viscoelastic supplementation injections, which involves a thick fluid, intended to provide lubrication to the knee joint.

Unfortunately none of those have proven to be effective when careful analyzed in research studies. Currently there are no medications available that have proven effective in modifying the OA disease process.

The latest foray into a possible medication to improve the symptoms of OA is supplementation with vitamin D.

Vitamin D and Knee Arthritis

Vitamin D is theoretically a good candidate medication for this disease. Prior studies have shown higher rates of OA and more knee pain in people with low vitamin D.

Vitamin D is also implicated in cartilage degeneration process, and higher vitamin D levels have previously shown to potentially decrease rates of cartilage degeneration in lab studies, but this has never been proven in people. But these studies have  significant issues that may cause concern.

First, people with low levels of vitamin D potentially live in colder climates, which means that this population has a specific genetic makeup based. These genes may effect OA more so than the vitamin D levels. Second, it is possible that people with low vitamin D levels live in colder climates and participate in less outdoor activities, and it is the activity level or choice of activity that is more closely linked to knee OA than vitamin D levels.

Researchers from Australia set out to answer the question of whether vitamin D supplementation effects knee pain and the amount of knee cartilage erosion over time in patients with knee OA. The results of their findings were recently published in the Journal of the American Medical Association (JAMA), one of the most respected journals in medicine.

In this study the researchers enrolled 413 participants with knee OA and low vitamin D levels. Participants were randomized to receive vitamin D supplementation versus a placebo (sugar pill).

The patients were then followed for two years, keeping track of knee pain, as well as the thickness of cartilage and any cartilage lesions (well defined areas where cartilage has eroded) using an MRI.

Unfortunately, the Australian researchers found that vitamin D did not improve knee pain or the degree of cartilage degeneration of the course of two years when compared to a sugar pill. It looks like we are still in the search for any medication that can truly change the natural course of OA. Based on these findings it is not recommended that patients take vitamin D supplements with the goal of improving pain from knee OA or preventing disease progression.

It is important to note that this study is the largest, and best-designed study on the topic. While previous studies identified Vitamin D as a potential supplement to help with knee OA, this study confirms that it is ineffective. So where does this leave us with regards to the treatment of knee OA? According to the American Academy of Orthopaedic Surgeons (AAOS) latest guidelines on the topic, the following are recommended treatments: continued low-impact activity/ strengthening/ neuromuscular education, weight loss ideally to a BMI of <25, and the use of NSAIDs or tramadol for symptomatic relief. Other options do not have enough evidence for the AAOS to support their use.

Management of Knee OA

Knee OA remains a difficult problem that we, as medical practitioners, are unable to solve. At this point we are left with conservative management options that seem to improve the symptoms of knee OA for a limited amount of time. Eventually, a significant amount of people continue to progress with regards to their knee OA. Once end-stage knee OA sets in and effects all three compartments of the knee, and the symptoms are too severe to deal with on a daily basis, the only time-proven surgical option is a total knee replacement.

In the meantime, researchers will continue to focus on novel medications that will hopefully one day have the ability to effect the progression of osteoarthritis. This is a goal that has been achieved in other types of arthritis, specifically rheumatoid arthritis. But unfortunately, the progress in this area of osteoarthritis has been slow. More progress has been made over the past few decades on the design and biomaterials used in total hip and total knee replacements. Research efforts continue in the hopes of designing total knees and total hips that last longer and longer, and are able to provide patients with a higher quality of life with less complications and lower rates of revision surgery.

Knee OA is a difficult problem, and although efforts in the pharmaceutical and healthcare industries continue to find a medication that can help with the progression of the disease, none have been found so far. Vitamin D was a strong candidate, and prior studies have found that people with low vitamin D levels have higher rates of knee OA and more knee pain. However the most recent study out of Australia has provided strong evidence that supplementation with vitamin D does not effect cartilage degeneration or knee pain in people with knee OA and low vitamin D levels.

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