An estimated 3.48 million Americans are projected to need knee replacement surgery, known as total knee arthroplasty (TKA), by 2030. Many of these patients experience muscle wasting as the knee is held immobile in the aftermath of surgery. This is especially true for the quadriceps, a group of four muscles on the front of the thigh. As a result, in the weeks following surgery, many patients have difficulty walking, climbing stairs, or rising from a chair. For some patients, muscle weakness can affect balance, increasing the risk of falls.
To test a possible treatment for this problem, researchers funded by the National Center for Medical Rehabilitation Research divided 28 seniors undergoing knee surgery into two groups: One group received a supplement containing essential amino acids (EAAs) following their surgery, and the other received a placebo.
The patients receiving the EAA supplements were able to perform better at a variety of tasks, including rising from a chair, walking, and climbing up and down stairs after surgery. From Magnetic Resonance Imaging results, the scientists observed that patients receiving the supplements also had better muscle strength at 2 and 6 weeks after surgery (PMID: 24135139).