Jumping ahead, crystal ball gazing and generally over thinking, I’m aware that the number and nature of knee surgeries I’ve had and the start of osteoarthritis mean it’s fairly likely that knee replacement surgery may figure at some point in the future.
I’ve touched on this briefly in another post but being curious about these things, and with the (untested) theory that hypermobility may be part of my problems in mind, I idly found myself googling ‘impact of hypermobility on knee replacement surgery’ one morning, which brought me to this article in the British Medical Journal and, in turn, down a rabbit hole of other ‘what if’ questions that led me to consider the post-op/prehab advice given to knee surgery patients (more on this, the point of the post, in due course).
But first, bear with me as I walk you through my musings:
We already know that having one ACL reconstruction surgery increases your risk of developing osteoarthritis, likely within 10 years of the surgery itself. Revision ACL reconstruction shortens those odds further, along with any other multi-ligament knee surgeries or operations that include trimming/removing the meniscus that helps protect the ends of the leg bones.
If joint hypermobility makes it more likely that ACL surgeries result in suboptimal outcomes, does the same apply to knee replacements? And, if your initial ACLr fails, leading to a revision surgery/surgeries, are you more likely to end up with advanced osteoarthritis at a younger age, which makes knee replacement surgery more likely in itself?
The BMJ article seems to back up the theory that joint hypermobility makes it more likely that knee replacement outcomes will be suboptimal (potential confirmation bias klaxon), in which case, what can patients do to stack the odds more in their favour?
How can we stop ACL reconstruction becoming the first in a series of of operations, each of which potentially makes the next surgery more likely in certain circumstances?
The BMJ article recommends the use of a constrained prosthesis for revision knee replacements, which led me to find out more about the different kinds of replacements available, their strengths and weaknesses. This is neatly summarised in this article on OrthoInfo
If you’re lucky enough to hold out without a knee replacement until your latter years - and with most prosthesis lasting around 20 years these days - hopefully it will be a once in a lifetime job and no need to worry.
If, on the other hand, the osteoarthritis progresses more quickly and you really need that knee replacement sooner rather than later, the chances are you’ll need revision surgery at some point, however successful the initial surgery is.
Which brings me on to the issue of bone quality.
In ACL reconstruction surgery, tunnels are drilled into the femur and tibia to attach the ‘reconstructed’ ligament. The widening or positioning of these tunnels in itself can be a cause of reconstruction failure. In revision surgeries, assuming the alignment is good, the original bone tunnels will be re-used so far as possible. However, I know with my revision surgery that even though my surgeon was pretty happy with the alignment of the original surgery tunnels, there were restrictions as to what he could do without ‘blowing out’ the tunnels. Once you get into revision revision territory, it seems that most surgeons will opt for a two-part surgery: the first grafting the existing bone tunnels to create a ‘clean slate’; before the second, reconstruction part of the surgery takes place at a later date.
As I said, bear with me…
When researching common causes of knee replacement failure - and reading the descriptions of the different types of total and unicompartmental knee replacement prostheses - problems relating to bone quality and the subsequent fixation of the prostheses come up time and time again.
So, if you’ve already had at least one ACL surgery, your tibia and femur are going to be in a suboptimal state before you begin. If you’ve had revision surgeries, they’re likely to be worse.
That’s before you throw into the mix the fact that bone density significantly decreases with age - especially for menopausal and post-menopausal women who, if you’re waiting as long as possible before undertaking knee replacement surgery, is likely to be most female candidates. Then there’s osteoporosis itself to consider, which will also have an impact.
Peak bone density is reached by your late 20s, after which it’s all about mitigating the losses and, while hormones, diet and undertaking weight-bearing exercise can help slow the decline, it seems to be a use it or lose it issue.
Which brings me to the point of this post.
As primarily a sporting injury, torn ACLs are relatively common among teenagers and adults in their 20s and 30s.
Once you’ve had your (hopefully successful) surgery and you’re getting back into action, with the potential for osteoarthritis and potential knee replacements down the line, would it not be sensible to make patients aware of the importance of building (if appropriate) and maintaining bone density through standard post-op advice? The concept of physio pre-hab has been around for a while in the ACL world and, I guess, this is just an extension of that thinking.
Of course, once osteoarthritis is established, many people give up high impact activities such as running, in favour of cycling, swimming and the like. While those can be a great way of keeping active and the joints moving, with bone density issues in mind, maybe patients should also be reminded of the importance of strength training and lower-impact weight-bearing exercise, such as walking. The same extends to diet, not least among teenage girls and young adults who can be put off eating calcium-rich foods due to body-image issues, especially in aesthetic sports and pastimes such as gymnastics and dance.
While not everyone will go back to a high-level of sport after their surgery, could making sure patients are informed about the issues and armed with the tools they need to optimise the condition of their bones post-ACL surgery improve outcomes further down the line?