Understanding Osteoarthritis of the Knee

By: Rajit Saluja, MD

If you have just been diagnosed with osteoarthritis of the knee or are experiencing knee pain and don’t know why, you probably want to know more about what osteoarthritis is, how it will affect your daily activities, and when you will feel better. At MOSH, we encourage patients to learn about their condition by answering these questions and suggesting you consult with our orthopedic experts to find the best treatment plan for your recovery and pain management. Understanding your knee osteoarthritis is the first step in returning to an active and healthy lifestyle.

What is Osteoarthritis of the Knee?

Osteoarthritis (OA) is the most common type of arthritis and has many names. It is sometimes called a degenerative joint disease, degenerative arthritis, or a “wear and tear” disease. OA is progressive and can lead to disability, but treatments are available.

OA occurs when cartilage in a joint deteriorates. Cartilage is a connective tissue that is found all over the body. Cartilage protects bones and joints by resisting compression and enhancing flexibility, among other functions. The leg bones are covered in articular cartilage, which helps with the smooth movement of the knee joint. Movement in a damaged joint produces friction and can cause significant pain, swelling, and stiffness.

Knees are particularly susceptible to OA. There are two types of knee osteoarthritis: primary and secondary.

  • Primary osteoarthritis in the knee involves articular cartilage degeneration without any apparent injury or reason. Primary knee OA is prevalent and is often the type affecting older people.
  • Secondary osteoarthritis in the knee means there is an underlying reason for the OA. Usually, this includes onset after a knee injury or another medical condition like rheumatoid arthritis.

Who Gets Osteoarthritis of the Knee?

Osteoarthritis is likely to occur in people aged 50 or older, but it can develop in anyone at any age. According to the Centers for Disease Control and Prevention (CDC), 32.5 million American adults have osteoarthritis. Other risk factors include:

  • Age: commonly the ‘wear and tear’ primary osteoarthritis.
  • Genetics: a family history of arthritis can make you more likely to develop knee OA.
  • Gender: women over 50 years of age are more likely to get osteoarthritis than men.
  • Weight: extra weight puts additional strain on your weight-bearing knee joints.
  • Occupations that cause repetitive knee injuries: this includes jobs that require prolonged kneeling, squatting, sitting, and heavy lifting.
  • Sports: athletics like soccer, baseball (catcher), basketball, running, and tennis can put extra stress on the knees.
  • Medical conditions: rheumatoid arthritis, gout, and metabolic disorders are some preexisting conditions that may cause secondary knee osteoarthritis.

How is Osteoarthritis Diagnosed?

A doctor will diagnose knee osteoarthritis using imaging results from an X-Ray, MRI, or ultrasound and your medical history (including your symptoms and risk factors). A physical examination of your knee will determine what movements cause pain and discomfort and if your knee has a diminished range of motion.

Your doctor will also rule out other conditions before diagnosing osteoarthritis, such as rheumatoid arthritis, fibromyalgia, hip arthritis, cruciate ligament injuries, meniscus tears, patellofemoral syndrome, or spinal stenosis.

How Will Osteoarthritis of the Knee Affect My Daily Activities?

OA develops gradually, and in the case of primary knee osteoarthritis, without a prompting injury. Osteoarthritis can be subtle, so checking in with yourself and evaluating your quality of life is recommended. The development of OA varies in signs and intensity for each individual. It can occur in one knee or both. Often, we stop doing things we usually do or subconsciously alter our daily routines to compensate for pain and decreased knee mobility. As a result, you may be doing less, changing positions often, limping, or feeling irritable or depressed. If you experience pain or are uncomfortable at night, your sleep will also be affected.

In general, if you have OA, you may notice a decrease in your knee’s function and an increase in pain after activities. In addition, once diagnosed with knee OA, your life may be minimally affected by treatments ranging from doctor’s appointments to knee exercises at home to limiting activities after surgery if needed.

Signs and Symptoms of Osteoarthritis in the Knees

Joint pain is one of the significant signs of osteoarthritis. Your knee may have many sensations, like a sharp pain or a deep ache. The pain may be in any part of the knee or in the sides and surrounding soft tissue. In the later stages of OA, your knee joint may feel unstable or like it might buckle. If you experience any of the following signs and symptoms in your knee, consult with a doctor:

  • Pain or discomfort
  • A perception of a lack of knee strength
  • Tenderness
  • A sensation of warmth
  • Swelling
  • Decreased mobility, range of motion, or function
  • Decreased flexibility
  • Pain or stiffness after prolonged sitting or standing
  • Stiffness, especially in the morning
  • A popping, crackling or grinding sound
  • Pain during or after activities like walking, running, or using stairs
  • Bone spurs
  • Pain with postural changes such as sitting to standing

When Will I Feel Better? How to Manage Pain from OA

The good news is that osteoarthritis of the knee is treatable, and you might feel better as soon as you begin recovery. Doctors will often treat osteoarthritis with conservative or non-surgical treatments first. You can consider surgical options if non-invasive treatments fail to relieve the pain and restore knee function. Conservative treatments will manage symptoms. These can include:


Thermotherapy is the use of cold and hot applications to a joint injury. Ice reduces pain and swelling, blocks nerve impulses, and numbs the knee area. Heat helps decrease pain, increase circulation and relaxes the surrounding muscles.

Physical Therapy

Physical therapy is one of the best ways to alleviate OA pain and improve joint function. Physical therapists will give you simple exercises to strengthen your knee and the muscles of your leg, improve balance and flexibility, regain range of motion, and manage pain. MOSH has experienced orthopedic PTs specializing in osteoarthritis rehabilitation.


Pain management is an integral part of the healing process. Therefore, your doctor will likely prescribe a regimen of over-the-counter NSAIDs (non-steroid anti-inflammatory drugs like ibuprofen) and pain relievers like acetaminophen. Other medication therapies include corticosteroid injections and duloxetine (Cymbalta).

Other Non-Surgical Treatments for OA

There are a few other non-surgical treatments that can help you manage knee osteoarthritis successfully. Treatments like:

  • Massage therapy
  • Acupuncture
  • Knee braces or assistive devices
  • Transcutaneous electrical nerve stimulation (TENS machine)
  • Occupational therapy
  • Viscosupplementation (hyaluronic acid injections create denser synovial joint fluid)
  • Weight Loss
  • Healthy Eating

Surgical Treatments for Osteoarthritis of the Knee

Surgical options are available if pain and knee function continue to deteriorate or the conservative treatments fail to provide relief. Knee surgeries are one of the most common and reliable of all major surgeries, but they can have some significant recovery times. Knee surgeries used to treat chronic OA include knee arthroscopy and total or partial knee replacement.

Osteoarthritis of the Knee and Bone Marrow

The medical field’s understanding of osteoarthritis has changed significantly from what it knew 20 years ago. Previously, the focus was on the narrowing of the knee joint space and the subsequent formation of bone spurs. However, it has been discovered that OA-related pain may largely be caused by chronic inflammation in the joint. This inflammation can cause additional damage to the bone just below the joint (subchondral bone) and present as bone marrow edema or swelling. These areas of bone marrow edema are also known as bone marrow lesions.

Bone marrow edema can be serious. Bones and bone marrow are comprised of living cells that require healthy blood flow. If that blood flow is cut off, the cells may die. Left untreated, the bone marrow lesions can lead to more severe damage and, in some cases, collapse the joint. Knees with bone marrow edema are nine times more likely to lead to total knee replacement.

When to Ask Your Doctor About Bone Marrow Lesions

If you have experienced any of the following conditions, please seek an evaluation for possible bone marrow lesions.

  • You received treatment for a torn cartilage, and the MRI shows mild to moderate OA with bone marrow edema.
  • You have previously undergone arthroscopic surgery to repair the damaged meniscus, but your pain has not decreased.
  • You have been diagnosed with mild to moderate OA, but your symptoms are not improving with either cortisone or hyaluronic acid injections.
  • You have been diagnosed with osteonecrosis in the knee region.

Solving Bone Marrow Lesions & Osteoarthritis Pain

Luckily, treating bone marrow edema, which can accompany mild to moderate OA, involves less invasive methods. Your doctor will assess your case’s severity, your overall health, and other factors before selecting a course of treatment that is right for you. Initial treatment is nonsurgical and can include rest, avoiding weight-bearing activity, injections, wearing a support brace, and modifying your activity.

If surgery is required and you are a MOSH patient, we will likely pursue a new biological approach to treatment known as intraosseous bioplasty (IOBP). This treatment is less invasive than a knee replacement. Blood from your bone marrow, which contains stem cells, is obtained during surgery, concentrated for injection, and mixed with the bone matrix. This material is then injected into the subchondral bone to stimulate the healing of the bone marrow lesions.

After surgery, expect three to four weeks of partial weight-bearing and light strengthening exercises. Next, patients will participate in physical therapy to rebuild strength and prepare to return to normal activities. IOBP shows excellent pain relief, improvement in activities, and better day-to-day function.

Osteoarthritis of the knee doesn’t have to stop you from living your life to the fullest. Many treatment options are available to help control the damage, manage pain, and regain knee function. You can return to your active lifestyle with some modification and under a doctor’s care. For more information about OA, bone marrow edema, or IOBP, please contact MOSH at 414-817-5800. You can also visit our MOSH Performance Center Clinic for premier orthopedic care with convenient walk-in appointments.

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