If Your Knee Replacement Really Hurts, Can You Blame Your Parents?
We’re just starting to understand how different we all are. In the 1960s and even when I graduated medical school in the 80s, physicians believed that all of their patients were the same. In fact, much of our current regulatory SNAFUs regarding cell therapies are based on this premise. Turns out, we physicians were wrong, most everyone is quite different in everything from how they heal, to how they react to medications, to the quality of their cells. Case in point this morning is a new study that looked to see if genes could explain the differences in medication orders after knee replacement surgery, meaning is the amount of post surgical knee replacement pain genetic in nature. The authors looked at KCNJ3 (GIRK1) and KCNJ6 (GIRK2) gene variations (which like all gene names sound a lot like Greek). Basically they looked for SNPs or Single Nucleotide Polymorphisms in the genes. To understand SNPs, you need to know that the DNA that makes us different is like a dictionary of words and letters. SNPs are therefore like different spellings of the same word that are off by one letter. That one letter genetic difference can have a huge impact on which proteins are produced and how the body behaves, just like changing one letter in a key word can completely change the meaning of a sentence. What did they find? Sure enough, they identified a SNP that when found in a patient corresponded to significantly more post operative medication needs after a knee replacement. Freaky! They also found that they could add up these SNPs to get a pain risk score based on genes and that this also explained why some patients felt more low back pain than others. The upshot? When you’re sucking down the narcotics like so many M&Ms after your knee replacement, don’t blame your surgeon, blame mom and dad!