Patients with poor nutrition before reverse shoulder replacement surgery have nearly seven times higher risk of developing serious infections afterward, according to a 2026 study of 157 shoulder surgery patients. Gram Research analysis shows that malnutrition, measured by a simple screening tool, independently predicted infection risk even after accounting for age and weight. The good news: improving nutrition before surgery appears to be a practical way to reduce this serious complication.
A new study of 157 shoulder surgery patients found that people with poor nutrition before their operation were nearly six times more likely to develop a serious infection afterward. Researchers used a simple nutrition screening tool to identify patients at risk. The good news: patients with better nutrition had similar pain relief and movement improvements after surgery. According to Gram Research analysis, this finding suggests that doctors should check patients’ nutrition before shoulder replacement surgery and help them improve it beforehand to prevent dangerous infections.
Key Statistics
A 2026 study of 157 reverse shoulder replacement patients found that those with poor preoperative nutrition had a 10.4% infection rate compared to 1.8% in well-nourished patients, a statistically significant difference.
Malnutrition was an independent risk factor for periprosthetic joint infection after reverse shoulder replacement, increasing odds of infection by 6.88 times according to multivariate analysis in a 157-patient study.
Among 157 shoulder replacement patients, 30.6% were classified as malnourished before surgery, and this group showed significantly lower blood protein and hemoglobin levels compared to the well-nourished group.
Despite higher infection rates, malnourished and well-nourished patients showed similar pain relief and functional improvement at 2 years after reverse shoulder replacement surgery in a 157-patient study.
The Quick Take
- What they studied: Whether a patient’s nutrition level before shoulder replacement surgery affects their risk of getting an infection after the operation.
- Who participated: 157 people who had reverse shoulder replacement surgery between 2014 and 2023. About 70% had normal nutrition, and 30% had poor nutrition. The malnourished group was older and had lower body weight and blood protein levels.
- Key finding: Patients with poor nutrition had a 10.4% infection rate compared to 1.8% in well-nourished patients. Poor nutrition increased infection risk nearly seven times, even after accounting for other factors.
- What it means for you: If you need shoulder replacement surgery, improving your nutrition beforehand may significantly reduce your risk of developing a serious infection. Talk to your doctor about nutrition screening before surgery. This is especially important for older adults and those with low body weight.
The Research Details
Researchers looked back at medical records from 157 patients who had reverse shoulder replacement surgery at one hospital over a 10-year period (2014 to 2023). They used a simple scoring system called the Geriatric Nutritional Risk Index to measure each patient’s nutrition status before surgery. This score looks at body weight, height, and blood protein levels to determine if someone is well-nourished or malnourished.
Patients were divided into two groups: those with normal nutrition scores (109 patients) and those with poor nutrition scores (48 patients). The researchers then compared what happened to each group after surgery, tracking infections, pain, movement, and overall shoulder function for at least 2 years.
The study used standard statistical tests to compare the groups and identify which factors independently predicted infection risk. This approach allowed researchers to see whether poor nutrition itself caused the higher infection rate, or whether other factors like age or weight were responsible.
Infections after joint replacement surgery are serious and expensive to treat. They can require additional surgery and antibiotics. If doctors can identify patients at high risk before surgery, they can take steps to prevent infections. This study shows that nutrition is one factor doctors should check. Unlike some risk factors that can’t be changed, nutrition can be improved before surgery, making it a practical target for prevention.
This study has several strengths: it followed patients for at least 2 years, used a validated nutrition screening tool, and included enough patients to find meaningful differences. However, it was conducted at a single hospital, which means results may not apply everywhere. The study looked backward at existing medical records rather than randomly assigning patients to groups, so we cannot be completely certain that poor nutrition alone caused the higher infection rates. Some important details about how infections were diagnosed and treated were not fully described.
What the Results Show
Of the 157 patients studied, 48 had poor nutrition before surgery (30.6%) and 109 had normal nutrition (69.4%). The malnourished group was notably older, had lower body weight, and had lower blood protein and iron levels.
The most striking finding involved infection rates. Patients with poor nutrition developed periprosthetic joint infections (serious infections around the new shoulder joint) at a rate of 10.4%, compared to only 1.8% in the well-nourished group. This difference was statistically significant and clinically important.
When researchers used advanced statistical analysis to account for other factors like age and weight, poor nutrition remained an independent risk factor. Specifically, patients with poor nutrition had 6.88 times higher odds of developing an infection. This means nutrition status itself, not just age or weight, appears to increase infection risk.
Surprisingly, the two groups had similar outcomes in most other measures. Pain relief was comparable, and most patients achieved meaningful improvement in shoulder function by 2 years, regardless of their nutrition status before surgery. The only other difference was that the malnourished group had slightly less forward arm movement at the 2-year mark.
Both groups showed similar improvements in pain scores, shoulder strength measurements, and overall function scores at 2 years after surgery. Most patients in both groups achieved what doctors call ‘minimal clinically important difference,’ meaning they noticed real improvement in their daily life. The malnourished group did show reduced forward arm movement compared to the well-nourished group, though this difference was small and may not affect daily activities significantly.
Previous research in other types of orthopedic surgery has shown that poor nutrition increases surgical complications. This study is among the first to specifically examine this relationship in reverse shoulder replacement surgery. The infection rate findings align with what researchers have observed in hip and knee replacement surgeries, suggesting that nutrition’s protective effect may apply across different joint replacement procedures. However, the finding that nutrition doesn’t affect pain relief or overall function improvement is somewhat surprising and differs from some earlier studies.
This study looked backward at existing medical records rather than following patients forward from the start, which limits what we can conclude about cause and effect. The study included only patients from one hospital, so results may not apply to all populations or surgical centers. The researchers did not describe exactly how they diagnosed and confirmed infections, which could affect accuracy. Some patients may have improved their nutrition between the initial screening and surgery, which wasn’t tracked. Finally, the study did not examine whether specific nutrients (like protein or vitamins) were more important than overall nutrition status.
The Bottom Line
If you are scheduled for reverse shoulder replacement surgery, ask your doctor to screen your nutrition status before the operation. If screening shows poor nutrition, work with a dietitian to improve your protein intake, body weight, and overall nutrition in the weeks before surgery. This appears to reduce infection risk significantly. The evidence for this recommendation is moderate to strong based on this study, though more research is needed.
This finding is most relevant for people over 65, those with low body weight, and anyone with known nutritional deficiencies scheduled for shoulder replacement surgery. It’s also important for surgeons and surgical teams who can implement preoperative nutrition screening. People with normal nutrition before surgery do not need to make changes based on this study alone.
Nutrition improvements should ideally begin 4 to 8 weeks before surgery to allow time for meaningful changes in body weight and blood protein levels. Infection risk reduction would begin immediately after surgery, with the critical period being the first few months after the operation.
Frequently Asked Questions
Does poor nutrition before shoulder surgery increase infection risk?
Yes. A 2026 study found patients with poor nutrition had 10.4% infection rates versus 1.8% in well-nourished patients after reverse shoulder replacement. Poor nutrition increased infection odds by nearly seven times, making preoperative nutrition screening important.
How is nutritional status measured before joint replacement surgery?
Doctors use screening tools like the Geriatric Nutritional Risk Index, which evaluates body weight, height, and blood protein levels. A score below 98 indicates malnutrition. This simple assessment helps identify patients who need nutrition support before surgery.
Can improving nutrition before shoulder surgery reduce infection risk?
Research suggests yes. Since poor nutrition independently predicted infections, improving nutrition through increased protein intake and weight management before surgery may reduce infection risk. Discuss nutrition optimization with your doctor 4 to 8 weeks before surgery.
Does nutrition affect pain relief after shoulder replacement?
No significant difference was found. A 157-patient study showed both well-nourished and malnourished patients achieved similar pain relief and functional improvement at 2 years, though malnourished patients had slightly reduced arm movement.
Who should get nutrition screening before shoulder replacement surgery?
Anyone scheduled for reverse shoulder replacement should receive nutrition screening, especially older adults, those with low body weight, or people with known nutritional deficiencies. Screening is quick and can identify those who need preoperative nutrition support.
Want to Apply This Research?
- Track daily protein intake (grams per day) and body weight (weekly) for 8 weeks before surgery. Set a goal of 1.2 to 1.5 grams of protein per kilogram of body weight daily, and aim to maintain or gain weight if currently underweight.
- Log meals and snacks daily to monitor protein sources (chicken, fish, eggs, dairy, beans, nuts). Set reminders to eat protein-rich foods at each meal. Use the app to schedule nutrition counseling appointments and track progress toward weight or protein goals.
- Create a pre-surgery nutrition dashboard showing weekly weight trends, daily protein intake averages, and progress toward nutrition goals. After surgery, track any signs of infection (fever, increased pain, redness, drainage) and report immediately to your surgical team. Continue monitoring nutrition for 3 months post-surgery to support healing.
This article summarizes research findings and should not replace professional medical advice. Nutrition screening and preoperative optimization should be discussed with your surgeon and healthcare team. If you are scheduled for shoulder surgery, consult your doctor before making significant dietary changes. This research applies specifically to reverse total shoulder arthroplasty and may not apply to other shoulder procedures. Always follow your surgical team’s preoperative instructions.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.