Well fellers, I've seen a few TKRs. Will normally have had a more than a couple on the books at any one time through my 25 years of healing the injured.
So,
@JimR is more or less correct when he says that the main reason knee replacements don't go so well is because people don't work hard enough to regain range of movement. Fair enough in one respect because knee replacements hurt and the time when you have to work it the most is when it is the sorest as the window to regain ROM is limited. People come up with all sorts of excuses... "It hurts too much now, I'll stretch it in a few weeks once it has settled down a bit" etc.
The main issue there is that the joint capsule (the collagen connective tissue that encloses all of your mobile joints) has a whacking big cut through the front of it and the knee joint capsule is quite sensitive to start with. However, as that incision heals, if it is not stretched frequently and firmly enough early on, that healing (scar) tissue will form as it feels like (ie. tighter than you would like) and will tighten further as it matures because that is what new healing tissue does. Result: Poor ROM. So that is the main reason.
BUT...
There are other reasons why the result can be sub-optimal. If the joint was stiff pre-op, you're going to be up against it trying to gain ROM post-op. Some patients actually go too hard in their rehab and traumatise the healing tissue beyond what it can adapt to. Some can develop adhesions (trash fibro-fatty tissue) internally that can limit ROM and cause pain and that is not the fault of the patient. Some do too much low-priority exercise (walking, strength work) in the early stages when regaining ROM is the only important thing and miss the window because they are burning through the knee's exercise tolerance doing stuff that is not important at that stage. Other issues can include infection, surgeon error and a range of other potential left-field problems that can be difficult to predict and/or identify and are also not the fault of the patient.
In the end, most TKRs come out well but it can take 12 months to get close to the end-point. A small percentage come out fair to poor. Sometimes the fault of the patient. Sometimes not.
So there you have it
So,
@JimR is more or less correct when he says that the main reason knee replacements don't go so well is because people don't work hard enough to regain range of movement. Fair enough in one respect because knee replacements hurt and the time when you have to work it the most is when it is the sorest as the window to regain ROM is limited. People come up with all sorts of excuses... "It hurts too much now, I'll stretch it in a few weeks once it has settled down a bit" etc.
The main issue there is that the joint capsule (the collagen connective tissue that encloses all of your mobile joints) has a whacking big cut through the front of it and the knee joint capsule is quite sensitive to start with. However, as that incision heals, if it is not stretched frequently and firmly enough early on, that healing (scar) tissue will form as it feels like (ie. tighter than you would like) and will tighten further as it matures because that is what new healing tissue does. Result: Poor ROM. So that is the main reason.
BUT...
There are other reasons why the result can be sub-optimal. If the joint was stiff pre-op, you're going to be up against it trying to gain ROM post-op. Some patients actually go too hard in their rehab and traumatise the healing tissue beyond what it can adapt to. Some can develop adhesions (trash fibro-fatty tissue) internally that can limit ROM and cause pain and that is not the fault of the patient. Some do too much low-priority exercise (walking, strength work) in the early stages when regaining ROM is the only important thing and miss the window because they are burning through the knee's exercise tolerance doing stuff that is not important at that stage. Other issues can include infection, surgeon error and a range of other potential left-field problems that can be difficult to predict and/or identify and are also not the fault of the patient.
In the end, most TKRs come out well but it can take 12 months to get close to the end-point. A small percentage come out fair to poor. Sometimes the fault of the patient. Sometimes not.
So there you have it
