Can Strong Back Muscles Lower the Risk of Knee Arthritis?
Our medical care system for orthopedics has a serious issue. It loves to chop people up into parts. You see the back guy for a spine problem, the foot and ankle guy, the shoulder doctor, and so on. The problem is that this isn’t consistent with the way we’re designed. We are one big connected machine. This morning, I’ll share yet another study that supports this idea by showing how your low back is critical for the health of your knees.
I’ve noticed for many years that patients with chronic low back pain are much more likely to have knee issues. In fact, they commonly have problems with the front of the knee, or patellofemoral joint. Why? The nerves in the lowest part of the low back that are commonly affected by back issues supply the glutes and hamstrings. When these muscles get a little weak or their contractions are off due to nerve issues, the quadriceps take over certain functions, and the result is that the knee cap gets overworked and, eventually, it’s cartilage gets burnt out.Learn about Regenexx procedures for knee conditions.
Understanding the Back Muscles
The back muscles are made up of three layers—superficial, intermediate, and deep. You’re probably most familiar with the superficial layer as it consists of the common low back muscles that you can see on the surface. We doctors call these the erector spinae.
A bit deeper and running from the head to the pelvis along either side of the spine is the intermediate layer of back muscles, collectively known as the paraspinal muscles. These are the iliocostalis, longissimus, and spinalis muscles. The superficial and intermediate layers are active in head, neck and shoulder movements, and working with the abdominal muscles, they are active in trunk rotation, forward and side bending, and back arching.
Even deeper, and also running the length of the spine are the deep layer of back muscles, collectively known as the transversospinal muscles. Within this layer is the multifidus muscle, which I often discuss on this blog. The multifidus muscle needs to be particularly strong as its major responsibility is the stabilization of the back bones (the vertebrae).
I’ll expand more on the multifidus muscle in a moment, but first let’s take a look at a new link that has been found between those intermediate paraspinal muscles and knee osteoarthritis.
The Back Bone Is Connected to the…Knee Bone?
Osteoarthritis (OA) is a degenerative condition, meaning it occurs over time as the cartilage that cushions and protects the bones wears down. When we talk about knee arthritis, OA is what we are typically dealing with as it is the most common type of knee arthritis. While knee arthritis is often associated with obesity or weakened muscles in the legs, a new study found there may be something else at play—weak back muscles, particularly the paraspinal muscles.
During physical exams of the musculoskeletal system, X-ray images were reviewed and body mass index (BMI), fat mass, and other measurements were recorded on study participants. When comparing subjects with knee arthritis to those without, researchers determined that those with knee arthritis had smaller paraspinal muscles, leading them to conclude that weaker back muscles were contributing to knee arthritis.
So it seems the back bone really is connected to the knee bone, and what happens in the back doesn’t stay in the back; weak back muscles, injured spinal nerves, and so on can affect any other part of the body’s interconnected system—the knee, the hip, the ankle, the shoulder, and more—and likewise a condition in the knee or another body part can affect the spine, the ankle, and so on. It’s all connected!
More on the Multifidus Muscle
Since the multifidus muscle is the ultimate spine stabilizer, and if this deep muscle is weak, it’s likely the other back muscles are too, let’s review more on the importance of keeping the multifidus strong as well. You can also watch my video on the multifidus below:
When the multifidus muscle weakens, it can atrophy (shrink) and lead to many problems. Let’s take a look at a small handful of issues can contribute to and result from multifidus atrophy:
- A herniated disc can irritate spinal nerves, disrupting nerve supply to the multifidus muscle, causing not only pain but also muscle atrophy.
- Multiple multifidus studies in the US National Library of Medicine have associated multifidus atrophy with back pain and a variety of disruptions in back function.
- Spinal fusion has been shown not only to heavily damage the spine-supporting multifidus muscle but also those intermediate-level back-movement muscles, the paraspinal muscles.
The upshot? The hyperspecialization of doctors has caused them and patients to believe that you are simply a back, a knee, or a shoulder. However, you are one big connected machine, and the cause of why your knees hurt may well be your back. So what happens if you ignore your back and just get knee surgery, avoiding the cause of your knee issues? More knee surgery! Hence, when you see the doctor for knee issues, an examination of your low back is critical!