Want to understanding the effects of mal-alignment? Think about the soles of your shoes. Walk on the outside of your feet regularly and what happens to your shoes? They start to wear on the outside.
So instead of your weight being distributed equally to the entire surface of the bottom of your foot, the forces are concentrated on a much smaller area on the outside. You wear out the lateral portion of your shoe much more quickly than the inside.
Let’s think about another common example: Wheel alignment
When your wheel alignment is off, what happens to your tires- they wear unevenly.The faulty alignment will cause some portions of the tire to be in contact with the road surface more than others and they will naturally wear faster.
Greater forces = increased wear on the surface
For a more complicated discussion of the finer points of wheel alignment go here. (I suggest this link because when you realize how complicated wheel alignment is, you will naturally wonder how complicated it might be getting your own knee aligned correctly)
Proper alignment in a knee replacement is necessary to distribute forces equally across the surface of the implant to ensure that there are no places that will wear out faster than others.
So now we come to the question of incision length.There is an optimal length where the surgeon has enough room to get the correct fit. Make the incision any smaller and you are asking him to perform the surgery looking through a hole about double the end of a paper towel roll- mostly for the sake of vanity.
Needless to say ultra small incisions can seriously impair the long term success of the surgery.
So when someone uses the marketing term “minimally invasive”, find out what they are really saying. Practically all knee replacement surgeries are minimally invasive in that no one is simply making a huge cut like they used to in the 80’s. And the majority of the surgeons use quad sparing techniques so that it takes less time to recovery. This is essentially the standard of care.
American Academy of Orthopedic Surgeons say this about minimally invasive knee replacement surgery on their website :
Minimally invasive knee replacement accomplishes everything that a traditional knee replacement does, but through a smaller incision (4- to 6-inch incision compared with an 8- to 10-inch incision). With the smaller incision come the potential benefits of a shorter hospital stay, shorter recovery, and a better looking scar.
Although there is no question that an artificial knee can be implanted through a smaller incision, doctors still don’t know whether it can be done as well as with the traditional approach.
Outcomes
Several early studies of minimally invasive knee replacement surgery have shown some benefits compared with traditional knee replacement, such as less blood loss, shorter hospital stay, and better motion. Other studies have shown a higher rate of complications with minimally invasive knee surgery, including poorer positioning of the knee implants.
1. Alignment matters..let your surgeon make a big enough incision to do a good job.
2. If your alignment is off, no amount of knee replacement therapy can correct that.
4 replies to "Alignment and Your Knee Replacement"
My wife in Western Australia had a prosthetic knee replacement nine years ago. She has never been able to walk without a stick or crutches ever since. After the operation and still in hospital I noticed that her foot was misaligned by at least seventy degrees to the left. I went to call over a nurse to investigate this and my wife burst into tears not wanting to go through the operation again. How did the medical profession not see this? So making the most stupid decision of my life, I relented but told my wife that she must see the doctor who operated on her ASAP. A few weeks later I took her to this surgeon’s practice but my wife insisted that she saw the doctor alone and so this surgeon got away with his botch-up because my wife is very non-assertive. I would have insisted on nothing less than a full leg scan from hip to toes to show this huge misalignment. Instead a scan only of the knee joint was done which revealed nothing. Over the next year or two my wife had another two scans done on her knee by two separate bone specialist professionals who both insisted that a full leg scan could not be done. Why? Covering up for a fellow professional? My wife came to accept the status quo and her ankle weakened considerably over the years due to the misalignment causing her to fall periodically without warning as her ankle gave way beneath her. Around a year and a half ago I contacted my local Member of Parliament about this matter to see why full leg scans or X-rays seem impossible to be done. My MP informed me that he could issue an order to force a medical centre to do a full leg scan on my wife. I told my wife. More tears and it appears that she has been conditioned to accept her fate and wants to bury her head in the sand and get on with life as it is. Should I just accept this?
John,
Sorry to hear what has happened with your wife. Many MD’s are loathe to criticize another MD and many do not want to be
tasked with correcting another’s shoddy work because of the increased potential for poor outcomes. I’m assuming your wife has a duck foot
when you say that the alignment is off by “seventy degrees” which is horrible if she had proper alignment prior to the surgery.
This will of course cause strain and ultimately malalignment up and down the kinematic chain. Unfortunately there are no easy solutions
as you know. I would try to find an older and experienced MD who might be willing and up for the challenge. As for the scans I can’t really imagine that
the knee scan is normal- to have that amount of malalignment at the ankle it would seem that her patella would be shifted laterally.So even though the joint may be “stable”
the mechanics are anything but normal. I hope that helps.
I had my knee replaced 3 years ago. Right afterwards my wife noticed my toes were pointed slightly outward. It never gave me a problem until recently I have started having Sciatica pain and pain in that knee when I climb stairs. My physical therapist wants me to concentrate on pointing my foot forward when I walk. I can do that but it seems to cause stress in my hip. Should I just continue to walk slightly pigeon toed?
The pain in the knee could be connected to the pain in the back as L3 issues radiate to the knee. I would address the Lumbar issue first- make sure you are sitting in a good chair, generally one in which you will NOT be rounding your low back or sitting sloughed as that puts stress on the back and can lead to sciatica (Put a towel roll back there if you need to). Take stress off that leg when you walk (use a cane) and don’t walk so far as to cause increased pain. (Lower pain or no change in pain is OK). Walk frequently if you can but within prescribed range. And finally don’t use the sciatica leg as your power leg on the stairs. Lead with the good going up and the bad going down to give the back a break.
When you get the back dealt with… all may just go back to normal even with a slight toe out as things have been for the last 3 years.