Osteoarthritis (OA) of the knee joint

What is Osteoarthritis (OA):

Osteoarthritis: Osteon means bone, Arthro means joints, Itis means inflammation. Now this terminology is technically incorrect and OA is actually not an inflammatory condition by nature and this is why some people now call it Osteoathrosis instead. The Osis part actually means degeneration, which is more accurate. So essentially breaking down the word tells us what it is, which is degeneration of the joint. More specifically it is degeneration of the articular cartilage of the joint. This is essentially damage and loss of cartilage until the joint is “bone on bone”. The bone actually starts to thicken and wear in response to the extra load on it, which causes bony outgrowths to form, called osteophytes. The synovium around the joint also thickens and produces extra fluid making the joint swell up.

How common is OA?

Osteoarthritis is very common, it affects about 80% of the population beyond the age of 55 years old (Kruger 2000). It was estimated that 9.9 million adults had symptomatic osteoarthritis of the knee in 2010 (Jevsevar et al 2013).
It is not exclusively a modern problem either:
Ruffer & Rietti (1912) noted that the majority of skeletal lesions coming from ancient Egypt were typically of Osteoarthritis!

What causes OA?

People think that it is caused by overusing your joints but contrary to popular belief overuse of a joint does not appear to cause Osteoarthritis, abnormal use however does.
For example people say “I used to run and this is why I have OA knee” but did you know that running significantly reduced OA and joint replacement risk (Williams 2013).

I actually see more people from an inactive sedentary background with OA than from a physical one. Joints like movement and activity and hate the opposite. The synovial fluid inside the joint acts like a lubricant and carries the nutrition for the cartilage. Weight bearing movement gets this working the best, therefore staving off OA rather than bringing it on. Now I can hear the footballers saying “hang on my knees are ruined from football!” Well evidence shows that the prevalence of knee OA in former elite soccer players is higher than the general population. (Kuijt 2012). However the issue with this is a few things, firstly when a player has a cartilage tear at the highest level they immediately have a meniscectomy, which is a removal of some cartilage. This goes against the evidence for this problem. The cartilage could heal over an estimated 6 month period of time with the correct rehab and therefore it should not actually need removal. If you remove cartilage you accelerate OA development as this evidence shows:

89% of patients experience osteoarthritis following meniscectomy (Rangger et al 1997).

The clubs want the quick fix in spite of any long term implications that won’t affect the club when the player is retired. Secondly the players with the OA knees now, played at a time that didn’t have the science behind it and they used to play on injuries and get painkilling injections etc. So provided you train correctly, don’t play through injury and don’t jump into surgery then you will do better than being a couch potato!

What are the symptoms of OA?

Pain: Especially on movement and weight bearing. Cold damp weather will make the pain worse and warm dry weather will lessen the pain.

Stiffness: This is worst in the morning and generally eases within an hour and continues to improve as the day goes on. Obviously if you are static for some time then this will also stiffen you up.

Swelling: As described before the synovium produces more fluid making the joint swell and thicken.

Muscle weakness: Pain and swelling inhibit the nerve supply to muscle, which makes the muscles waste over time. Also due to the symptoms of OA your activity levels drop and the muscles decondition in response to this.

Crepitus: This is the noise that your knee makes. Commonly people describe grinding or crunching, which is the rough joint surfaces rubbing across each other and the noise from the fluid in the joint moving around.

What makes OA hurt?

Articular cartilage has no nerve supply, so weight bearing on the surface of the joint is pain free. However bone has lots of nerve and blood supply so when the cartilage is gone then it will hurt. This is obviously true but pain in OA starts before the cartilage actually exposes any bone. But why?

More recent evidence points to the fact that it is far more complex. For example, chondrocyte cell death and the production of new tissue has been observed in OA. In an attempt to regenerate itself, an increase in protein synthesis by the chondrocytes has been seen, this osteochondral angiogenesis derived from expression of growth factors has been theorised as to a cause of pain in OA (Girbes et al 2013). Muscle spasm is also a factor, as muscle will go into a protective spasm in response to the pain from the OA itself and this will add to the overall pain experienced. This is why evidence shows a reduction in overall pain levels when you treat the muscle especially the trigger points (Girbes et al 2013).

Neuroplastic changes with chronic pain can also occur, which is when the nervous system physically changes itself and actually creates its own pain signal irrespective to the origin of the pain. This is most evident in phantom limb pain, as the origin of pain was the foot or limb, but removal of this doesn’t actually get rid of the pain!
The nerve pain is highlighted when you consider the medications that are most effective at various times with OA. At first Non-steroidal anti-inflammatory drugs (NSAID’s) work best but they eventually become ineffective leading to the use of Gabapentin and Amitriptyline, which are nerve pain relieving medications. Also if pain was simply from the joint itself then you would expect that a joint replacement would cure the pain and this doesn’t happen in reality although it can help.

What treatments help OA knee?

Exercise:

Exercise & education are recommended for physical management in Osteoarthritis (Larmer et al 2014). It appears however that the effect is short term rather than long term (Davis & Mackay 2013) & (van Bar et al 2001).

Strengthening, low-impact aerobic & neuromuscular exercise are beneficial forms of exercise for OA knee (Jevsevar et al 2013) &(Brosseau et al 2009). Strengthening with or without weight-bearing & aerobic exercises are effective for pain relief in knee osteoarthritis (Tanaka  et al 2013).

Performing land- & water based exercise are helpful for mild-to-moderate knee OA (Golightly et al 2012).
Flexibility exercises are considered important by Uthman et al (2013).
Endurance exercises such as stationary cycling is an effective exercise option for mild to moderate knee osteoarthritis & has been found to improve pain on walking (Salacinski et al 2012).
Lin et al (2009) found that non-weight-bearing proprioceptive training significantly improved outcomes in OA knee.
Tai Chi:  Moderate evidence for short-term improvement of pain, function & stiffness in osteoarthritis of the knee (Lauche et al 2013).
These type of exercises should be done 3 x per week for optimal improvements (Juhl et al 2014).

Acupuncture:

Generally in OA, acupuncture may lead to small improvements in pain & physical function after 8 weeks (Manheimer et al 2010). However, for osteoarthritis of the knee it doesn't appear to be any better than placebo according to Chen et al (2013). Turner & Igo (2013) found that compared to sham there is inconclusive evidence that acupuncture improves pain or function in knee osteoarthritis.

Electrotherapy:

There were no additional benefits of using TENS alongside current management of osteoarthritis of the knee (Palmer et al 2014).
Electromagnetic field treatment may provide moderate benefit for osteoarthritis sufferers in terms of pain relief (Yu et al 2013).
Overall Davis & Mackay (2013) found that interferential current, short wave diathermy, ultrasound & neuromuscular electrical stimulation did not demonstrate benefit over placebo in OA knee.

Psychological interventions:

Self-management strategies based on cognitive therapy principles are beneficial in knee OA (Davis & Mackay 2013).

Weight loss:

Weight loss is vital for patients with symptomatic OA of the knee & a BMI ≥ 25 (Jevsevar et al 2013).

Medication:

Jevsevar et al (2013) recommends nonsteroidal anti-inflammatory drugs or Tramadol for knee OA.

Supplements:

People with osteoarthritis who take glucosamine: may get reduced pain, improved function & probably won't have side effects (Towheed 2009). That being said Jevsevar et al (2013) doesn’t recommend using glucosamine & chondroitin for OA of the knee.
Viscosupplementation (e.g. hyaluronan) is an effective treatment for knee arthritis benefiting pain & function according to Welch et al (2009). But this was not considered effective by Jevsevar et al (2013).

Orthotics (insoles):

Depending on the issues, insoles can be slightly beneficial but more specifically, guidelines have found that lateral wedge insoles shouldn’t be used for medial compartment knee OA (Jevsevar et al 2013).

Injections:

Steroid injections appear to be safe and effective for OA knee according to Raynauld et al (2003) but both steroid and placebo injections reduced pain in this study but ultrasound imaging showed a reduction in synovial “inflammation” in the steroid group. (Hall et al 2013). If you have a Steroid injection then they will not perform a total knee replacement for 6 months afterwards so be aware of this before deciding.

Keyhole surgery:

Arthroscopic debridement for osteoarthritis of the knee doesn't improve pain or function compared to placebo (Laupattarakasem et al 2009).

Joint replacement (Total Knee Replacement):

This is the final point, when all other treatment fails and the OA is just too severe. However, between 10 & 35% of patients have a poor outcome following a total knee replacement so don’t think that it’s an easy fix (Beswick et al 2012).
Cryotherapy may improve the range of movement at the knee in the first one to two weeks after joint replacement (Adie et al 2012).
Another benefit found is that joint replacement surgery can boost the economy: Improvements allow patients to return to work & earn & spend rather than be supported (Dall et al 2013).

So there you go, all you need to know regarding OA knee.

If you need any further information or would like to book an appointment then call Hawkes Physiotherapy on 01782 771861 or 07866195914

WWW.HAWKESPHYSIOTHERAPY.CO.UK