Knee Osteoarthritis… Do I have it? How do I get better?
Arthritis is derived from the Greek words arthro meaning “joint” and itis meaning “inflammation.” It is defined as an acute or chronic joint inflammation that is often associated with pain, stiffness, and structural damage. There are several different types of arthritis but osteoarthritis (OA), which is degenerative and commonly referred to as “wear and tear” arthritis, is the most common. Knee OA accounts for approximately 80% of the disease’s total burden.1 In fact, 14 million people in the United States have symptomatic knee OA, with more than half being younger than 65 years of age.2 The major risk factors for OA include advancing age, female sex, history of joint trauma, and obesity. In one study, obesity increased the likelihood of developing knee OA by 6.8 times, compared to healthy-weight individuals.3 Genetic risk factors likely also play a significant role, but research is ongoing to further determine the heritability of OA.
Pain and stiffness are the primary symptoms of OA and typically develop gradually over time, however, a sudden onset of symptoms is also possible. Symptoms are usually worse in the morning, with activity, and with movement after a period of inactivity, such as standing up and walking after prolonged sitting. Additionally, pain may worsen with high-impact activities, such as jogging or tennis. Other common symptoms include joint swelling, inability to fully extend or bend the knee, warmth around the knee, crepitus (a “snap crackle and pop” sensation within the joint), and weakness and instability (i.e. knee “buckling”).
A thorough physical exam is an important part of diagnosing knee OA. Often, the exam will reveal tenderness along the knee joint line (where the femur meets the tibia bone to form the joint). Other common physical exam findings in knee OA include joint swelling, warmth, crepitus, decreased and painful range of motion, bony enlargement, and abnormalities in gait (or the way you walk).
In knee OA, the cartilage in the joint gradually wears away, and as it thins and frays, the space between the bones decreases. Although X-rays do not directly show the cartilage, they may reveal narrowing of the joint space due to cartilage loss. Other common X-ray findings include changes in the bones themselves (like subchondral sclerosis which is an increased density of bone and cysts) and osteophytes (or bone spurs).
More advanced imaging, such as MRI, is typically not needed to make the diagnosis of knee OA. However, it may be indicated to evaluate for other causes of knee pain when the physical exam and X-ray imaging findings are unclear or if a secondary cause of knee pain, such as a meniscus or ligament injury, is suspected.
Although there is no cure for OA, a variety of non-surgical treatment options are available to ease pain and improve function and quality of life. In cases when there is severe OA and conservative care is not effective in managing pain and restoring function, referral to a joint replacement surgeon may be considered.
Exercise and weight loss when indicated are the foundations of a healthy knee joint. A large literature review concluded there is moderate to high-quality evidence suggesting exercise alone can improve knee pain and function in patients with knee OA.4 Typically, a combination of low-impact aerobic fitness training (e.g., walking, cycling, water aerobics, etc.) and lower-limb strengthening exercise is prescribed; however, individualized exercise plans, tailored to meet each patient’s unique needs, are best.
Maintaining a healthy weight is also important to reduce wear and tear on the knee joint and improve symptoms of knee OA. Carrying excessive weight puts excess pressure on the knee, which adds up over time. The good news is that even a small amount of weight loss significantly reduces the weight bearing load placed on the knee. For example, for every one pound of weight loss, there is a reduction of four pounds of pressure at the knee. Therefore, by losing 10 pounds, the pressure placed on the knee decreases by 40 pounds with each step.6 Studies have shown that a combination of dietary modifications in addition to regular exercise is most effective in achieving healthy weight loss and improving knee pain associated with OA.5
An individualized therapy program, focused on addressing each patient’s unique biomechanical deficits, is also an effective treatment for knee OA.7 Targeted stretching and strengthening of the supporting musculature can correct biomechanical malalignment, reduce stress through the joint, and improve pain and function. Both land-based and aquatic physical therapy programs are beneficial.8 Manual therapy performed by physical therapists and offloading knee braces can also provide pain relief.
Acetaminophen (Tylenol) can reduce pain and is generally considered a first-line medication for treating knee OA. Taking more than the maximum daily limit can cause liver dysfunction, however, so caution is advised.
Over-the-counter nonsteroidal anti-inflammatory medications (NSAIDs), such as ibuprofen and naproxen, can be helpful. Consultation with a physician, however, is always recommended as NSAIDs can cause stomach upset, cardiovascular problems, bleeding problems, and kidney damage. Topical NSAID preparations may be better tolerated and can also provide benefit. More specific NSAIDs called COX-2 selective NSAIDS are also available by prescription. These NSAIDs selectively target and block the cyclooxygenase-2 enzyme, which is responsible for pain and inflammation, while reducing the risk of stomach irritation and gastrointestinal ulceration associated with non-selective NSAIDs..
There are a variety of intra-articular (or into the joint) injections and other therapies which can be considered if knee pain does not adequately improve with more conservative treatments. At Desert Spine and Sports Physicians, we use ultrasound guidance for all intra-articular knee injections to ensure precise needle placement and maximum treatment effectiveness.
Cortisone injections, or steroids, can help temporarily reduce pain from knee OA and improve function.10, 11 In general, routine use of repeat steroid injections is discouraged as this can actually damage the cartilage over time. However, steroid injections can be useful as a treatment for moderate to severe pain from knee OA and during acute pain flares.
Sometimes referred to as “gel” injections, viscosupplementation involves the injection of hyaluronic acid (HA) into the knee joint. HA is naturally found in the knee joint and works by acting like a lubricant and shock absorber. HA injections typically last for 6 months, and some studies have found these injections can provide even longer-term pain relief and improved function.14, 15
Platelet Rich Plasma injections
Platelet rich plasma (PRP), often referred to as a regenerative therapy, has also been proven to be an effective treatment for knee OA.12, 13 PRP involves taking a small amount of the patient’s own blood, spinning it in a centrifuge machine to separate out the cellular components, and then injecting the platelet rich portion into the joint. The platelets contain growth factors which promote the body’s natural healing process and help to repair and rebuild damaged tissue and reduce pain. A recent meta analysis found that PRP may be superior to HA in improving pain and function in knee OA with the effects lasting up to a year or longer.12
Genicular nerve block and radiofrequency ablation
Patients with chronic knee pain that has failed to adequately respond to more conservative treatments may be candidates for genicular nerve ablation. The genicular nerves are a group of sensory nerves that innervate the articular joint surface of the knee. A genicular nerve block involves the injection of a local anesthetic that temporarily interrupts the pain signals coming from the knee and traveling to the brain. The injection is performed with small needles using fluoroscopy (X-ray guidance) to ensure accurate and safe needle placement. If the temporary block provides effective pain relief, then genicular nerve radiofrequency ablation, or burning of the nerves, is likely to provide more long-lasting pain relief.9
If you are having knee pain, please call to schedule an appointment at Desert Spine and Sports Physicians so that our team of physiatrists can help diagnose and treat your issue. We offer appointments and in-office procedures at all of our Phoenix, Scottsdale, and Mesa locations, and we look forward to helping decrease your pain and improve your function.
- Vos T, Flaxman AD, Naghavi M, et al. Years lived with disability (YLDs) for 1160 sequelae of 289 diseases and injuries 1990-2010: A systematic analysis for the Global Burden of Disease Study 2010. Lancet 2012; 380:2163.
- Vina ER, Kwoh CK. Epidemiology of osteoarthritis: literature update. Curr Opin Rheumatol 2018; 30:160.
- Coggon D, Reading I, Croft P, et al. Knee osteoarthritis and obesity. Int J Obes Relat Metab Disord 2001; 25:622.
- Fransen M, McConnell S, Harmer AR, Van der Esch M, Simic M, Bennell KL. Exercise for osteoarthritis of the knee: a Cochrane systematic review. Br J Sports Med. 2015 Dec;49(24):1554-7. doi: 10.1136/bjsports-2015-095424. Epub 2015 Sep 24. PMID: 26405113.
- Messier SP, Mihalko SL, Legault C, Miller GD, Nicklas BJ, DeVita P, Beavers DP, Hunter DJ, Lyles MF, Eckstein F, Williamson JD, Carr JJ, Guermazi A, Loeser RF. Effects of intensive diet and exercise on knee joint loads, inflammation, and clinical outcomes among overweight and obese adults with knee osteoarthritis: the IDEA randomized clinical trial. JAMA. 2013 Sep 25;310(12):1263-73. doi: 10.1001/jama.2013.277669. PMID: 24065013; PMCID: PMC4450354.
- Messier SP, Gutekunst DJ, Davis C, DeVita P. Weight loss reduces knee-joint loads in overweight and obese older adults with knee osteoarthritis. Arthritis Rheum. 2005 Jul;52(7):2026-32. doi: 10.1002/art.21139. PMID: 15986358.
- Deyle GD, Allen CS, Allison SC, Gill NW, Hando BR, Petersen EJ, Dusenberry DI, Rhon DI. Physical Therapy versus Glucocorticoid Injection for Osteoarthritis of the Knee. N Engl J Med. 2020 Apr 9;382(15):1420-1429. doi: 10.1056/NEJMoa1905877. PMID: 32268027.
- Silva LE, Valim V, Pessanha AP, Oliveira LM, Myamoto S, Jones A, Natour J. Hydrotherapy versus conventional land-based exercise for the management of patients with osteoarthritis of the knee: a randomized clinical trial. Phys Ther. 2008 Jan;88(1):12-21. doi: 10.2522/ptj.20060040. Epub 2007 Nov 6. PMID: 17986497.
- El-Hakeim EH, Elawamy A, Kamel EZ, Goma SH, Gamal RM, Ghandour AM, Osman AM, Morsy KM. Fluoroscopic Guided Radiofrequency of Genicular Nerves for Pain Alleviation in Chronic Knee Osteoarthritis: A Single-Blind Randomized Controlled Trial. Pain Physician. 2018 Mar;21(2):169-177. PMID: 29565947.
- Bannuru RR, Schmid CH, Kent DM, Vaysbrot EE, Wong JB, McAlindon TE. Comparative effectiveness of pharmacologic interventions for knee osteoarthritis: a systematic review and network meta-analysis. Ann Intern Med. 2015 Jan 6;162(1):46-54. doi: 10.7326/M14-1231. PMID: 25560713.
- Jüni P, Hari R, Rutjes AW, Fischer R, Silletta MG, Reichenbach S, da Costa BR. Intra-articular corticosteroid for knee osteoarthritis. Cochrane Database Syst Rev. 2015 Oct 22;(10):CD005328. doi: 10.1002/14651858.CD005328.pub3. PMID: 26490760.
- Belk JW, Kraeutler MJ, Houck DA, Goodrich JA, Dragoo JL, McCarty EC. Platelet-Rich Plasma Versus Hyaluronic Acid for Knee Osteoarthritis: A Systematic Review and Meta-analysis of Randomized Controlled Trials. Am J Sports Med. 2021 Jan;49(1):249-260. doi: 10.1177/0363546520909397. Epub 2020 Apr 17. PMID: 32302218.
- Chen P, Huang L, Ma Y, Zhang D, Zhang X, Zhou J, Ruan A, Wang Q. Intra-articular platelet-rich plasma injection for knee osteoarthritis: a summary of meta-analyses. J Orthop Surg Res. 2019 Nov 27;14(1):385. doi: 10.1186/s13018-019-1363-y. PMID: 31775816; PMCID: PMC6880602.
- Di Martino A, Di Matteo B, Papio T, Tentoni F, Selleri F, Cenacchi A, Kon E, Filardo G. Platelet-Rich Plasma Versus Hyaluronic Acid Injections for the Treatment of Knee Osteoarthritis: Results at 5 Years of a Double-Blind, Randomized Controlled Trial. Am J Sports Med. 2019 Feb;47(2):347-354. doi: 10.1177/0363546518814532. Epub 2018 Dec 13. PMID: 30545242.
- Huang TL, Chang CC, Lee CH, Chen SC, Lai CH, Tsai CL. Intra-articular injections of sodium hyaluronate (Hyalgan®) in osteoarthritis of the knee. a randomized, controlled, double-blind, multicenter trial in the Asian population. BMC Musculoskelet Disord. 2011 Oct 6;12:221. doi: 10.1186/1471-2474-12-221. PMID: 21978211; PMCID: PMC3203101.