Dislocating Knee (Subluxing Patella)

Sarah in Mirfield, England asks:

"I have a condition called subluxing patella. I also have a torn meniscus cartilage. My problem is not due to an injury as I have been able to 'dislocate or sublux' my knee from an early age. Over the past five years this has got extremely worse (it also comes with a very loud cracking sound, which freaks many a hospital staff out, apparently they have not seen a case as extreme as mine). My knee will dislocate anything from 15-30 times a day. Such as when I'm bending down, pivoting, using stairs or after I walk too far (running is out of the question). I have Hypermobility syndrome although I have no other real problems but the knee. It's the right knee that's affected. Occasionally my left knee will dislocate but only once or twice a week.

My knee is totally unstable, and restricts everything I do. I am currently waiting my second arthroscopy to fix my meniscus, although my consultant said this is unlikely to make much of a difference.

I have some questions about this and was hoping you could help."

David Wales, Clinical Specialist Physiotherapist responds:

"Will physiotherapy help? "

"As a physio I am always inclined to say that it is worth doing physiotherapy rather than not, although considering that you have had your problem for quite some time and have seen no improvement then I have to say that physiotherapy treatment will not cure your problem."

"If my meniscus is torn due to the subluxing, will this happen again in time? "

"The menisci and knee joint generally are susceptible to further damage whenever there is knee joint instability. Hyper Mobilty Syndrome represents extreme instability so if you are repeatedly suffering these injuries then you may suffer further damage."

"What are my chances when it comes to arthritis?"

"Arthritis tends to be accelerated secondary to joint damage. Because you are subluxing or dislocating over 15 times each day then the chances of developing arthritis are increased if your situation is not addressed. However, damage to joint surfaces from dislocation and subluxation tends to be less in individuals who have lax joints and Hypermobility Syndrome. In these individuals the joint pops out so easily there may be little or no tissue damage."

"What is the best knee support/brace that I could get to help support my knee?"

"The most appropriate knee brace for Patellofemoral Instabilty is the Donjoy Hinged TRU PULL Advanced Knee Brace. However this brace is designed for people who have suffered one or two subluxations or for those with pain around the knee cap due to Patellofemoral Pain Syndrome. I don't think that this brace will be effective in your case, due to the very severe symptoms and the way that Hypermobility Syndrome is affecting your knees. Patella subluxations tend to occur when the knee is bent, or when there is rotation of the knee so it is worth asking your orthopaedic doctor if a hinged knee brace that limits the amount of knee bend, such as a good quality Hinged Knee Brace would be suitable for your right knee."

"Will my left knee eventually do the same in time?"

"Due to the fact that you have Hypermobility Syndrome then your left knee may also become more affected, but it is impossible to predict with certainty."

"What other damage could be caused in the future?"

"As you've alluded to earlier, meniscal damage and general joint damage may precede osteoarthritis of the affected joints. However, damage to joint surfaces tends to be less in individuals who have lax joints and Hypermobility Syndrome, where the subluxations are relatively less painful and the joint goes back in place easily."

"Is there anything I should avoid that might make this worse?"

"Try and avoid all the specific movements which you know tend to cause a subluxation. However I understand that this may be very difficult in your case, due to the subluxations occurring during such trivial, everyday activities."

"Overall I would recommend that you consult an orthopaedic consultant who specialises in knee problems, particularly Patellofemoral problems. They will be able to give you specific advice following a thorough history and physical examination of your knees. There are many factors to consider related to Patellofemoral Instability and the orthopaedic consultant will be able to explain these to you following his assessment of your knees. The orthopaedic consultant will also be able to let you know if a non surgical or surgical approach is indicated. There are several surgical approaches to Patella Instability, with the more modern techniques having a particularly good degree of success."

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Article published: February 2007