New Research on Total Knee Replacement


A new study from researchers at TOSH – The Orthopedic Specialty Hospital sheds new light on the relationship between increased proinflammatory cytokines and decreased vitamin D levels. The study has been published in the journal

Medical Hypotheses

Cytokines are molecules that aid cell-to-cell communication in immune responses and stimulate the movement of cells towards sites of inflammation, infection, and trauma. “Vitamin D is an important factor in a patient’s recovery following an orthopedic procedure,” says Tyler Barker, PhD, senior author of the study and a TOSH clinical researcher. “As we learn more about why vitamin D levels decrease postsurgery, we can more easily identify ways to mitigate that decrease and improve the patient’s recovery.”

How does vitamin D affect rehabilitation after a knee replacement? 
Vitamin D is an essential micronutrient that regulates inflammatory events, skeletal muscle size and function, and bone health. Following a total knee replacement, rehabilitation efforts can be slowed due to lower levels of vitamin D. During the study, a patient was followed 46 days before surgery and for six weeks following the total knee replacement. Fasting blood samples were obtained at specific points during the study and used to identify vitamin D and proinflammatory cytokine levels. Patients saw asmuch as a 74 percent decrease in vitamin D levels during the three to eight weeks post-surgery, while cytokine levels increased proportionately. 

Preventing low levels of vitamin D could impact recovery. 
“Pending further study of our initial hypothesis and results, our research could advance our knowledge pertaining to the role of inflammatory cytokines on vitamin D metabolism in humans,” says Vanessa Henriksen, a TOSH athletic trainer and research assistant. “These discoveries may also have a broad impact on the healthcare system and patient care by ameliorating common diseases and disease-related outcomes associated with low vitamin D.” 

As patients are discharged after orthopedic surgery, protecting against these low levels of vitamin D may be accomplished by including diverse dietary, supplemental, or regulated sun exposure regimens in discharge planning. Future research will be instrumental in supporting the causality of the decreased vitamin D levels and increased pro-inflammatory cytokines and may translate across multiple disciplines in healthcare.