Knee injuries are quite common in sports medicine and can be caused by an accident, injury, or the wear-and-tear of aging. The first step in making a full recovery is identifying the cause of knee pain right away before the injury worsens and possibly becomes irreversible. If you're looking for what may cause pain on the inner side of the knee, look no further: we have a comprehensive review of what may underlie your inner knee pain below.
The Anatomy of the Knee
Let's start with a quick review of the knee before we hone in on the inner knee area, as each part of this joint is intrinsically connected to the rest.
- Bones: The bones of the knee joint include the femur (thighbone), tibia (shinbone), and the patella (kneecap). They give the knee structure.
- Muscles: The muscles involved in the knee joint include the quadriceps (top of your thighs), hamstrings (back of your thighs), and the calf muscles (the gastrocnemius, soleus, and the tibialis posterior). These muscles allow for movements like standing, sitting, walking, jumping, running, and flexing.
- Tendons: The tendons of the knee attach muscle to bone and include the quadriceps tendon that connects the quadriceps muscle to the kneecap and the patellar tendon that attaches the kneecap to the shinbone (technically making it a ligament, but it's called the patellar tendon all the same).
- Ligaments: Ligaments are connective fibers that attach bone to bone, and after the dubiously named patellar tendon, there are four main ligaments of the knee: the ACL (anterior cruciate ligament) that runs centrally through the joint connecting the thigh and shin bones; the PCL (posterior cruciate ligament) that is larger and stronger than the ACL and runs along the back of the knee between thigh and shin bone; the LCL (lateral collateral ligament) that stabilizes the outside of the knee; and the MCL (medial collateral ligament) that stabilizes the inside of the knee.
- Tissues: Other connective tissues in the knee include cartilage caps that prevent the thigh and shin bone from grinding together, the meniscus that sits between those cartilage caps, and the knee bursae (fluid-filled sacs that help lubricate many joints, including the knee).
Evaluating Pain on the Inner Side of the Knee
Knee problems are quite common due to the nature of the joint. Our ankle, knee, and hip joints are tasked with supporting the weight of the entire body when walking, sitting, and moving throughout the world, but the knee in some ways is the most confined. The hip is a ball-and-socket joint with a wide rotation range, and the ankle, though functionally an up-and-down-style hinge joint just like the knee, nevertheless can also rotate the foot in ways the knee joint cannot move.
This rigidity in the knee gives us the support we need to stand but is also vulnerable to sudden switching movements that can cause slips and injuries among the bones and tissues of the joint. These injuries can result in pain and sometimes permanent loss of function, and this is why it's important to quickly identify knee pain.
When it comes to pain on the inner side of the knee, here are some important distinctions.
- Medial knee pain is the term most frequently used to describe inner knee pain. "Medial" means "middle," which seems like a misnomer, but because the inner-knee tendon is known as the medial collateral ligament, it is aptly termed in health care settings.
- Pain to the inside of the knee may be gradual (as with tendonitis from overuse) or sudden (as with a ligament tear), and may be perceived as an aching or sharp pain. Knowing how to describe the nature of your pain helps with diagnosis.
- Pain above the knee or within the knee may have entirely different causes than inner knee pain, so be as precise as possible in the location of your pain, as it may lead to faster and more successful treatment. Inner knee pain could be a torn meniscus injury. Inner kneecap pain is also distinct and could be due to patellofemoral pain syndrome, aka runner's knee, (which includes front of the knee pain as well).
Pain on Inner Side of Knee: Common Causes
Here are the most common causes of pain on the inner side of the knee.
1. MCL Injury
A sprain or tear to the medial collateral ligament (MCL) causes pain at the inside of the knee. MCL injuries are often caused by either a direct impact to the ligament (say if you were accidentally kicked during a soccer match) or a sharp, twisting motion (again, one that is common in a sport like soccer, basketball, or football). A fall could also cause this sort of injury, making it an injury more likely to be suffered by elderly adults.
2. Pes Anserine Bursitis
Bursae sacs are found throughout the body in over 150 locations, including in the shoulders, hips, and knees. The pes anserine bursa is the sac located on the inner side of the knee, and if it becomes irritated or inflamed, you've got a case of pes anserine bursitis. This condition may present as swelling, stiffness, or pain, and is a frequent complaint of runners and other athletes. Pes anserine bursitis usually requires no further treatment beyond rest and at-home self-care.
3. Meniscus Tear
Menisci are rubbery pads of cushioning tissue that help absorb shocks in your joints. There are two menisci located in each knee: one on the lateral or outer side of the knee, and one on the inner side known as the medial meniscus. Should the medial meniscus become damaged, you may experience instability, swelling, and pain on the inner side of your knee.
4. Rheumatoid or Osteoarthritis
Arthritis is an umbrella term that covers different types of the disease and can afflict just about any joint in the body.
- Rheumatoid arthritis: Inner side of the knee pain could be a symptom of this autoimmune disease that attacks the body's joints and causes painful inflammation. Managing rheumatoid arthritis requires a doctor's advice and guidance, even if it's mild enough to treat with over-the-counter anti-inflammatories such as ibuprofen or even natural anti-inflammatory remedies. Without professional medical supervision from a rheumatologist, this condition could worsen drastically.
- Knee osteoarthritis: While osteoarthritis can afflict many joints throughout the body due to aging (it's known as "wear and tear" arthritis or degenerative joint disease), osteoarthritis of the knee may manifest as pain at the inside of your knee.
5. Medial Plica Syndrome
Medial plica syndrome is a specific version of synovial plica irritation that can manifest as pain throughout the knee joint (such as inner-side knee pain, pain behind the kneecap, anterior knee pain, etc.). The synovial plica is the inner surface of the synovial membrane of the knee joint, and it can become irritated or inflamed in response to injury. This may be the only cause of your knee pain, or it could be one symptom of a more serious underlying cause.
Treatment Options for Inner Knee Pain
Whatever the cause or causes of knee pain, once you've consulted a medical professional, you'll receive specific advice. Here is a quick overview of the variety of treatment options that may be suggested at that time.
- RICE: For mild injuries, you may be sent home with instructions to Rest, Ice, Compress, and Elevate your knee joint.
- Physical therapy: Your doctor or physical therapist may suggest targeted stretches to help you build leg strength around bad knees to ensure that you heal properly and prevent future injury.
- Knee braces: Knee sleeves and braces help stabilize the knee while you heal and help prevent re-injury as you return to sporting or daily activities. You may choose to wear knee sleeves while working out indefinitely, as they can provide extra support to your knee going forward.
- Surgery: A ligament injury like an MCL tear may require surgery to repair and specific rehab advice post-op.
The Inner Side Track
Pain on the inner side or inside of your knee can be debilitating, and in some cases (if left untreated) permanent. For these reasons, it's important to identify the cause of the pain and find the most effective solution for it as soon as possible.