Pretty much. Lots of pain...very little pain. Easy flexion...impossible flexion. Done with opioids quickly...still on them months later.
In one incarnation of myself decades ago, I was a pretty good statistician. Know that there is something called The Bell Curve...a line that starts low on the left, gets high in the center and then low again on the right. Given enough data, you can develop a probabalistic model where anyone in the population will fall under some part of the curve.
In a simplistic model where, for example, the mean (average) post-op pain level of the entire population is, say, 5 with a calculated standard deviation of 1, it can be projected that about 68% of people will have a pain level of 4 to 6 while 93% of people will have a pain level somewhere in the 3 to 7 range, all falling within two standard deviations of the mean. Once we get to 3+ standard deviations (the "outliers"
, you are covering 99.99% of the population.
I've talked to people with pain levels of almost zero to 10 so everyone, you can say, is different...on a personal level. However, they ALL do, as part of the "population", fall somewhere under the bell curve, and remember that pain levels are very far from objective. I would rather model PT experience from start to full flexion as the elapsed time, number of sessions and measured flexion are all quantifiable data points.
My guess is that if you surveyed post-TKR patients, they would probably report average pain levels in the 8+ range with a very small standard deviation (espiecially if the scale is limited to a maximum of 10). That guess would include a lot of data points in the 7-10 range. Based on that theory, people with little to no pain post-op would be many standard deviations to the left (lower side) of the mean and would be considered either statistical outliers or incredibly lucky people. I'd put them on a bus for Vegas and roll the dice with them...
Note: In a 2011 Canadian study on the effect of pre-op risk factors as predictors of 3-year post-op pain levels in over 1,800 hip and knee replacement patients, the observed risk factors (subjective pain level, bone spacing, differential diagnoses and more) accounted for only 20% of the variance in current pain levels. In other words, the docs have no way of predicting in advance of a replacement operation if you will have recurring pain in the future. However, they did find correlations between post-op pain and the presence of depression, higher body mass index, younger age, and female gender. Since you can't do anything about the latter two, I'd suggest you stay as thin and happy as possible...and maybe be glad you're older.
