The Impact of Weight Loss on Knee Osteoarthritis

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The Impact of Weight Loss on Knee Osteoarthritis

Knee osteoarthritis is one of the most common causes of pain and disability in the older population in addition to hip osteoarthritis. Osteoarthritis or OA is a common disorder that affects many adults.  It is the leading cause of functional limitations in older adults which often includes difficulty with walking and managing stairs.  OA is a major health problem and arthritis related conditions are one of the most common reasons a person visits their doctor.  OA can lead to functional decline and the likelihood of being diagnosed with OA increases with age. Related: What you can do NOW to prevent knee problems in the future



What is knee osteoarthritis? Knee osteoarthritis symptoms and breakdown 
The knee joint is made up of bones, cartilage, ligaments and tendons.  Articular cartilage covers the end of the long bone of the thigh which is the femur and the end of the tibia which is the bone in the lower leg in addition to the undersurface of the patella or knee cap.  This articular cartilage is a smooth substance that helps the knee bones glide smoothly across each other as the knee bends and straightens.    In a normal joint, this cartilage can act as a shock absorber and allow for even movement of the joint without pain but when OA is present the cartilage degrades and becomes thinner, which leads to pain.  The cartilage can disappear all together in the more advanced stages of the disease which leads to significant joint pain and difficulty moving the knee.  The symptoms of knee OA include pain, stiffness and muscle weakness which can decrease functional activity tolerance such as walking and stair management and lead to a decreased quality of life. 

OA is a degenerative, chronic and at times progressive joint disease that can be caused by cartilage breakdown or due to a secondary reason caused by other conditions or trauma.  OA patients often complain of pain with movement and typically these people are in more pain with weight bearing activities such as walking or managing stairs when there is the greatest amount of stress or pressure on the joints.  

Knee osteoarthritis treatment options 
Patients will generally end up needing physical therapy and possibly various types of injections for pain control unless they are at the stage where surgery is indicated.  If a patient is not in the end stages of knee OA, then more conservative treatment is usually recommended initially.  There are various studies on different types of interventions including multiple modes of exercise which in turn leads to weight loss, which is important in the management of knee OA because losing weight will help to decrease pressure on the joint.  Hydrotherapy which may include water aerobics and swimming may help to reduce pain, improve strength and improve flexibility.  Hydrotherapy can be performed and is often performed in warm water which has also been show to help alleviate pain and stiffness associated with knee OA.  Appropriately paced (and potentially low impact) aerobic exercise can also reduce joint pain and increase a person’s ability to perform daily tasks.  

Related: Search over 500 workout videos by length, difficulty, muscles used & more (we even have a low impact category!) 

Losing weight while working around knee problems
It's hard enough to lose weight when your body is fully functioning; it's not hard to imagine that it would be especially difficult while dealing with knee or joint issues.

Hydrotherapy and exercise (again; pace, form and appropriate difficulty level are crucial here) can help aide in weight loss in this patient population; particularly because weight reduction is one intervention to help alleviate the symptoms of knee OA.  A healthy diet can also have a significant impact on both bodyweight and your body's ability to heal itself, so make sure that you're eating well.

It has been shown in the research, that people that are overweight experience higher rates of knee OA than those who are not overweight. The force that occurs in the knee joint with weight bearing activities is 3-6 times a person’s body weight.  It makes sense then that if you are overweight you are placing more force on the knee joint.  The greater force on the knee joints over time can lead to the early onset or a steady progression of knee OA.  

The good news
Pain reduction and improvements in walking speed have been shown in those with knee OA who are prescribed weight loss procedures and this occurred in people at various stages of the disease.  People with knee OA should be encouraged to begin a weight loss program and should seek recommendations from their healthcare provider to decrease their weight to alleviate symptoms. People with knee OA that are surgical candidates may not be able to have a total knee replacement until their BMI is under a certain number which is another reason that this population needs to actively manage their weight.  The main reasons that someone with knee OA that is also overweight needs to begin a weight loss program are the following: reduce pain, reduce stress on the knee joint, slow or delay the disease process and be prepared for a possible surgery in the future should it be required. 

To be safe; always make sure to talk to your doctor about any lifestyle changes you intend to make, to make sure that they are safe for you and your personal health care scenario.

Written by L. Augustyn, Physical Therapist

References
Bhatia D, Bejarano T & Novo M. Current interventions in the management of knee osteoarthritis. J Pharm Bioallied Sci. 2013; 5(1):30-38.
Fransen M, McConnell S & Harmer AR, et al. Exercise for osteoarthritis of the knee: a Cochrane systematic review. Br J Sports Med. 2015; 49: 1554-1557. 
Hauk, L. Treatment of knee osteoarthritis: a clinical practice guideline from the AAOS. Journal of the American Academy of Orthopaedic Surgeons. September 2013.
Juhl C, Christensen R, Roos EM, Zhang W, Lund H. Impact of exercise type and dose on pain and disability in knee osteoarthritis. Arthritis & Rheumatology. 2014; 66(3): 622-636. 
Michael JWP, Schluter-Brust KU, Eysel P. The epidemiology, etiology, diagnosis, and treatment of osteoarthritis of the knee. Dtsch Arztebl Int. 2010; 107 (9): 152-162
White DK, Neogi T, Nguyen UDT, Niu J, Zhang Y. Trajectories of functional decline in knee osteoarthritis: the osteoarthritis initiative.  Rheumatology. 2016; 55:801-808.