For many older adults with hip fractures, loss of physical function and independence are significant. Only 40% of older adults with hip fractures recover to pre-injury levels of function, and as many as 20% of hip fracture patients living in the community prior to injury require nursing home care after the fracture. 

Functional deficits are attributed to the loss of skeletal muscle that occurs early after injury—and one potential contributing factor is nutrition. 

“Malnutrition is common in the older population,” says Michael Willey, MD, orthopedic surgeon and assistant professor in the University of Iowa Department of Orthopedics and Rehabilitation. “After an injury like this, patients tend to get even fewer nutrients because of pain medications and requirements for anesthesia, which leads to worsening nutritional deficiencies.” 

Previous studies have offered preliminary evidence that essential amino acid (EAA) supplementation mitigates loss of muscle mass after operative fixation of extremity and pelvic fractures and before and after total knee arthroplasty.  

Could the same be true after hip fractures? 

It’s not clear how EAA supplementation leads to improved muscle physiology, but it is “a potentially game-changing intervention to prevent these negative outcomes after trauma,” Willey says. 

Willey and his UI colleagues—in collaboration with researchers and clinicians from the University of Oregon, the Slocum Center for Orthopedics and Sports Medicine in Eugene, Oregon, and Johns Hopkins University—are embarking on a randomized, placebo-controlled clinical trial to see if EAA supplementation will increase skeletal muscle metabolic activity, reduce inflammation, and prevent atrophy after hip fracture in older adults. 

The trial will enroll 60 hip fracture patients, ages 65 and older. Within four days of hospitalization, they will receive EAA supplementation or a placebo. Muscle biopsy and serum analysis will be performed during hip repair surgery and again at two weeks and six weeks post-surgery to assess the physiologic response of skeletal muscle to EAA supplementation. The researchers also will assess the impact on total body skeletal muscle mass and physical function. In addition to the University of Iowa, patients will be enrolled at the Slocum Center. Muscle biopsy and serum analysis will be performed at the University of Oregon. 

Results from the study, funded by a grant from the Orthopedic Trauma Association, could provide evidence for EAA supplementation to guide clinical practice. 

“Right now, essential amino acid supplementation is an understudied intervention that could help preserve function and independence for older patients experiencing hip fractures,” Willey says. “If it works, it could be a low-cost and low-risk intervention with considerable potential to meet metabolic demands and preserve skeletal muscle.”