ShoulderBuzz Evidence Card 1 — Preoperative nutrition and retear risk after arthroscopic rotator cuff repair (Shitara et al., 2024)

Who it studied

143 patients age 65 or older who underwent arthroscopic rotator cuff repair and had 2-year postoperative MRI evaluation.

What they did

A single-center retrospective prognostic study used the Geriatric Nutritional Risk Index (GNRI), calculated from albumin and body size, to evaluate whether preoperative nutrition status was associated with healed vs retear status after repair.

What they found

·        The overall retear rate was 20.3%.

·        Albumin and GNRI were lower in the retear group than the healed group.

·        Lower GNRI status and larger medial-lateral tear size were independent risk factors for retear; GNRI <103 was a higher-risk threshold in their analysis.

What it means

For older rotator cuff repair patients, nutrition status may be a meaningful, modifiable risk marker. GNRI is not a treatment by itself, but it can help identify patients who may benefit from preoperative nutrition review and optimization.

Link: PubMed abstract

ShoulderBuzz Evidence Card 2 — Dietary habits and speed of recovery after rotator cuff repair (Liu et al., 2023)

Who it studied

55 patients followed for 12 months after rotator cuff repair and categorized into rapid-recovery vs slow-recovery patterns.

What they did

An observational cohort study used a food-frequency questionnaire and postoperative shoulder scores to test whether habitual food patterns were associated with faster recovery.

What they found

·        Habitual meat intake, fruit intake, and wheat-flour foods were associated with rapid recovery.

·        Steamed/boiled flour products and soup-mixed foods such as noodles/wontons were the wheat-flour patterns most associated with rapid recovery.

·        The study found associations, not proof that these foods caused faster healing.

What it means

A practical patient message is food-first recovery: adequate protein, fruit, and enough energy/carbohydrate may matter during rehab. Because this was a small observational study, it should support sensible nutrition habits rather than strict diet rules.

Link: PubMed abstract | Free full text

ShoulderBuzz Evidence Card 3 — Low albumin and short-term outcomes after arthroscopic rotator cuff repair (McGlone et al., 2021)

Who it studied

15,846 arthroscopic rotator cuff repair cases in the ACS-NSQIP database from 2011 to 2015; 4,152 had preoperative albumin values.

What they did

A retrospective cohort study compared patients with normal albumin to patients with hypoalbuminemia, defined as serum albumin <3.5 g/dL, and evaluated postoperative admission and extended length of stay.

What they found

·        Hypoalbuminemia was associated with higher adjusted odds of postoperative admission.

·        Hypoalbuminemia was also associated with higher adjusted odds of extended length of stay.

·        The study supports albumin as a risk-stratification marker, not a complete nutrition diagnosis.

What it means

For outpatient arthroscopic cuff repair, low albumin can flag higher perioperative risk. It may be reasonable to screen higher-risk patients and consider nutrition counseling before elective surgery.

Link: PubMed abstract

ShoulderBuzz Evidence Card 4 — Hypoalbuminemia and outcomes after open rotator cuff repair (Quan et al., 2022)

Who it studied

3,052 open rotator cuff repair patients in ACS-NSQIP from 2006 to 2019 with albumin measured within 90 days before surgery.

What they did

A retrospective database study compared normal albumin (>=3.5 g/dL) with hypoalbuminemia (<3.5 g/dL), adjusting for demographic and medical confounders.

What they found

·        4.5% of included patients were hypoalbuminemic.

·        After adjustment, hypoalbuminemia was associated with extended hospital stay and hospital readmission.

·        The largest adjusted association was for extended length of stay.

What it means

The open repair population reinforces the same message: low albumin is a warning sign. Nutrition risk may be especially relevant for larger, open, or more medically complex shoulder procedures.

Link: PubMed abstract

ShoulderBuzz Evidence Card 5 — Oral arginine/MSM/collagen/bromelain blend after rotator cuff repair (Gumina et al., 2012)

Who it studied

90 patients with large posterosuperior full-thickness rotator cuff tears treated with arthroscopic repair.

What they did

A prospective randomized study compared rotator cuff repair plus an oral supplement blend for 3 months vs repair without the supplement. The supplement contained arginine L-alpha-ketoglutarate, methylsulfonylmethane, hydrolyzed type I collagen, and bromelain.

What they found

·        Pain at 6 months was lower in the supplement group.

·        MRI repair integrity at final follow-up was slightly better in the supplement group.

·        Objective functional scores did not clearly improve compared with control.

What it means

This is one of the few shoulder-specific supplement trials. It suggests a possible role for a combined collagen/arginine-style supplement after repair, but the study was small and product-specific, so it should not be generalized to every collagen or tendon supplement.

Link: PubMed abstract

ShoulderBuzz Evidence Card 6 — Vitamin D deficiency, early pain, and retear after arthroscopic rotator cuff repair (Chen et al., 2022)

Who it studied

89 patients age 40 to 75 with full-thickness rotator cuff tears treated with arthroscopic repair and postoperative MRI assessment.

What they did

A retrospective cohort study compared patients with preoperative vitamin D deficiency (<20 micrograms/L) to patients with sufficient levels.

What they found

·        The vitamin D deficient group had a higher retear rate than the control group.

·        Pain scores were worse at 1 and 3 months postoperatively in the deficient group.

·        Later pain/function scores were not consistently different.

What it means

Vitamin D is best framed as a screening and correction issue. Patients should not self-prescribe high doses, but identifying and treating deficiency before repair may be reasonable to discuss with the treating team.

Link: PubMed abstract | Free full text

ShoulderBuzz Evidence Card 7 — Vitamin D and rotator cuff repair outcomes: systematic review/meta-analysis (Yeo et al., 2025)

Who it studied

A systematic review and meta-analysis evaluating published studies on serum vitamin D and rotator cuff fatty degeneration and repair outcomes.

What they did

The authors synthesized correlation data and post-repair outcomes to clarify whether vitamin D levels reliably predict healing and clinical results.

What they found

·        Higher vitamin D levels were associated with lower fatty degeneration and possible lower retear risk.

·        The review concluded vitamin D deficiency does not necessarily translate into clearly worse post-repair outcomes across all measures.

·        This helps balance stronger claims from individual studies.

What it means

The patient-facing message should be balanced: vitamin D deficiency is worth identifying and correcting, but vitamin D is not a stand-alone rotator cuff healing treatment.

Link: PubMed abstract

ShoulderBuzz Evidence Card 8 — Leucine and rotator cuff muscle atrophy in a rat model (Zheng et al., 2019)

Who it studied

A tendon-transection rat model of massive rotator cuff tears, not a human clinical trial.

What they did

The study tested leucine-rich diet effects on supraspinatus atrophy, muscle pathology, autophagosome formation, and PI3K/AKT/mTOR signaling.

What they found

·        Leucine supplementation attenuated supraspinatus muscle atrophy and muscle injury in the model.

·        Leucine reduced autophagy-related protein expression and reactivated PI3K/AKT/mTOR signaling.

·        The anti-atrophy effect was blunted when PI3K/mTOR signaling was inhibited.

What it means

This supports biologic plausibility for leucine/EAA strategies in rotator cuff muscle preservation, but it does not prove that leucine supplements improve human shoulder outcomes. It is best used as mechanistic support for adequate protein and EAA intake.

Link: PubMed abstract

ShoulderBuzz Evidence Card 9 — Omega-3 supplementation for rotator cuff-related shoulder pain (Sandford et al., 2018)

Who it studied

Patients with rotator cuff-related shoulder pain participating in a randomized trial of long-chain omega-3 polyunsaturated fatty acid supplementation.

What they did

A randomized controlled trial tested whether omega-3 supplementation improved pain/disability outcomes in rotator cuff-related shoulder pain.

What they found

·        Omega-3 supplementation may have produced a modest effect on disability and pain outcomes.

·        The trial supports cautious discussion of omega-3s as an adjunct, not a primary treatment.

·        Exercise and rehabilitation remained important context.

What it means

Omega-3-rich foods such as fatty fish can fit well into a recovery diet. Supplements may not be appropriate for everyone, especially patients taking blood thinners or preparing for surgery, so clinician review matters.

Link: PubMed abstract

ShoulderBuzz Evidence Card 10 — Nutrition and tendon health/tendinopathy systematic review (Hijlkema et al., 2022)

Who it studied

A systematic review of nutrition interventions and tendon health/tendinopathy across tendon conditions.

What they did

The review evaluated whether nutrition strategies help prevent or treat tendinopathy, including protein/collagen-related and anti-inflammatory concepts.

What they found

·        The tendon nutrition literature is promising but heterogeneous.

·        Collagen/gelatin with vitamin C and loading exercise is one commonly discussed strategy, but evidence quality varies by tendon and population.

·        The review does not support one universal supplement protocol for all tendon problems.

What it means

For ShoulderBuzz, this supports a broad tendon-health theme: nutrition should complement progressive rehab/load management, not replace it. Food-first protein, vitamin C-rich foods, and thoughtful supplement discussions are reasonable.

Link: PubMed abstract

ShoulderBuzz Evidence Card 11 — Amino acid supplementation after orthopedic surgery: systematic review of RCTs (Brown et al., 2025)

Who it studied

10 randomized clinical trials across orthopedic and spine surgery populations, including adult reconstruction, hip fracture, trauma, and spine cohorts.

What they did

A systematic review evaluated EAA, BCAA, and CEAA supplementation effects on muscle atrophy and postoperative function.

What they found

·        Doses, timing, and formulations varied widely, making meta-analysis difficult.

·        Several studies showed favorable muscle size/composition or mobility outcomes, particularly around TKA.

·        The authors concluded amino acids may help prevent muscle wasting but additional studies are needed.

What it means

Amino-acid supplementation is a reasonable evidence-informed concept for orthopedic recovery, but standard dosing is not settled. Cards should avoid promising a universal benefit and should emphasize individualized medical review.

Link: PubMed abstract

ShoulderBuzz Evidence Card 12 — Pre- and post-surgical nutrition review for preserving muscle (Hirsch et al., 2021)

Who it studied

A narrative review focused on orthopedic surgery and strategies to preserve muscle mass, strength, and function around surgery.

What they did

The authors reviewed the surgical stress response, carbohydrate/protein timing, essential amino acids, protein quality, and practical perioperative nutrition timing.

What they found

·        Surgery produces a catabolic stress response that increases protein breakdown and amino acid demand.

·        The review emphasizes high-quality protein distributed across the day and strategies to improve intake before and after surgery.

·        It highlights that protein goals are often not met in surgical patients.

What it means

This is the backbone for the patient page: shoulder recovery needs enough energy and high-quality protein, especially during periods of immobilization and rehab. It also supports a practical timeline around surgery while still deferring fasting instructions to the surgical team.

Link: PubMed abstract | Free full text

ShoulderBuzz Evidence Card 13 — The role of amino acid supplementation in orthopaedic surgery (Jazayeri et al., 2024)

Who it studied

An AAOS review of amino acid supplementation in orthopedic surgery, with emphasis on malnutrition, sarcopenia, perioperative muscle loss, and wound healing.

What they did

The review summarized EAA, conditionally essential amino acids such as arginine/glutamine, HMB, creatine, and cystine/theanine, including commonly used doses and clinical settings.

What they found

·        The review describes nutrition status as a modifiable risk factor.

·        It summarizes EAA evidence for muscle preservation and CEAA/HMB evidence for wound healing and reduced complications in selected orthopedic populations.

·        It notes implementation barriers and need for standardization.

What it means

This supports a clinician-facing ShoulderBuzz message: nutrition is increasingly part of orthopedic optimization, but supplements should be used thoughtfully and not as a substitute for meals, rehab, sleep, and risk-factor control.

Link: PubMed abstract

ShoulderBuzz Evidence Card 14 — Conditionally essential amino acids after fracture fixation (Hendrickson et al., 2022)

Who it studied

400 adults undergoing operative fixation of pelvis or extremity fractures at a level-I trauma center.

What they did

A prospective randomized trial compared standard nutrition with or without twice-daily CEAA supplementation for 2 weeks. The supplement contained arginine, glutamine, and HMB.

What they found

·        Overall complications were lower in the CEAA group than the control group.

·        Control subjects lost fat-free mass at 6 weeks, while the CEAA group maintained it early.

·        The benefit was strongest for early complications and early skeletal muscle wasting.

What it means

Although this is not shoulder-specific, it is a high-quality orthopedic trial showing that targeted amino acids can matter during injury/surgery recovery. It supports the broader muscle-preservation and wound-healing rationale.

Link: PubMed abstract

ShoulderBuzz Evidence Card 15 — Essential amino acids after total knee arthroplasty: 2-year RCT (Ueyama et al., 2023)

Who it studied

52 analyzable patients after unilateral total knee arthroplasty for primary knee osteoarthritis.

What they did

A double-blind randomized trial compared EAA supplementation at 9 g/day vs lactose placebo from 1 week before surgery to 2 weeks after surgery, with ultrasound and strength follow-up to 2 years.

What they found

·        At 2 years, rectus femoris muscle area and quadriceps strength recovery were greater in the EAA group.

·        Clinical outcome scores were not significantly different between groups.

·        The study suggests a long-term muscle benefit from a short perioperative EAA course.

What it means

This supports the concept of protein/EAA support around orthopedic surgery, especially when muscle loss is expected. It should be translated cautiously to shoulder patients because it studied knees, not rotator cuff repair.

Link: PubMed abstract

ShoulderBuzz Evidence Card 16 — Essential amino acids to reduce muscle loss after TKA (Dreyer et al., 2018)

Who it studied

Older adults recovering from total knee arthroplasty.

What they did

A randomized study evaluated perioperative EAA supplementation and postoperative muscle volume changes after TKA.

What they found

·        The PubMed abstract reports that EAA supplementation was safe and reduced loss of muscle volume in older adults recovering from TKA.

·        The study is part of a consistent TKA signal that EAAs can mitigate, but not eliminate, post-surgical atrophy.

·        Functional effects may vary by outcome and time point.

What it means

For shoulder recovery, the relevance is indirect but useful: periods of sling use and reduced activity can accelerate muscle loss, so adequate protein/EAA intake may be a reasonable supportive strategy.

Link: PubMed abstract

ShoulderBuzz Evidence Card 17 — CaHMB, vitamin D, and protein after hip fracture surgery (Ekinci et al., 2016)

Who it studied

75 older female patients with hip fracture and nutritional risk; 62 were included in the final analysis.

What they did

A randomized controlled study compared standard postoperative nutrition with or without an enteral product providing CaHMB, vitamin D, and protein for 30 days.

What they found

·        Wound-healing time was shorter in the supplemented group.

·        More patients in the supplemented group were mobile on postoperative days 15 and 30.

·        Muscle strength at day 30 was higher in the supplemented group.

What it means

This is not a shoulder study, but it supports a practical recovery principle: in nutritionally vulnerable older orthopedic patients, protein plus muscle-support nutrients may improve early mobility and wound recovery.

Link: PubMed abstract

ShoulderBuzz Evidence Card 18 — Protein supplementation and enhanced recovery after posterior spine fusion (Khalooeifard et al., 2022)

Who it studied

80 analyzable patients undergoing elective posterior spine fusion surgery.

What they did

A randomized double-blind placebo-controlled trial compared a diet adjusted to 1.2 g/kg/day protein plus 36 g/day whey protein supplement vs a similar diet plus starch placebo from 48 hours before surgery to 1 month after surgery.

What they found

·        The protein group had a higher vertebral fusion rate.

·        Surgical site infection, pain, and wound-healing scores were better in the protein group.

·        Inflammation markers decreased more and albumin/total protein/IGF-1 increased more in the protein group.

What it means

This supports perioperative protein as part of enhanced recovery, especially for tissue healing and wound recovery. It is spine-specific, so it should inform general orthopedic nutrition rather than direct rotator cuff promises.

Link: PubMed abstract

ShoulderBuzz Evidence Card 19 — High-protein anti-inflammatory nutrition intervention in arthroplasty patients (Schroer et al., 2019)

Who it studied

Elective hip and knee arthroplasty patients across a five-hospital network, including a malnourished subgroup identified by low albumin.

What they did

A prospective population analysis evaluated a patient-education nutrition program emphasizing a high-protein, anti-inflammatory diet and compared outcomes over time between study and control hospitals.

What they found

·        Malnourished patients who received the intervention had shorter length of stay compared with malnourished control-hospital patients in the same period.

·        Hospital charges and 90-day total charges were lower in the intervention cohort.

·        The intervention was education-based and surgery was not automatically cancelled or delayed.

What it means

This is valuable for a patient-facing ShoulderBuzz page because it supports practical food-based education: protein goals, fruits/vegetables, whole grains, nuts/seeds, and limiting excess sugar/simple carbohydrates.

Link: PubMed abstract

ShoulderBuzz Evidence Card 20 — Protein/amino acid supplementation in hip and knee arthroplasty: systematic review/meta-analysis (Khani et al., 2025)

Who it studied

19 studies involving 903 hip or knee arthroplasty patients receiving oral or intravenous protein/amino acid supplementation.

What they did

A systematic review and meta-analysis evaluated muscle atrophy, muscle strength, function, and other recovery outcomes after perioperative supplementation.

What they found

·        EAA supplementation reduced quadriceps femoris and hamstring muscle atrophy in pooled analysis.

·        Effects on muscle strength and function were mixed.

·        The authors called for standardized research to define best dosing, formulation, and timing.

What it means

This is a good capstone source: perioperative protein/amino acid supplementation has supportive evidence for reducing muscle atrophy in arthroplasty, but the functional impact is not guaranteed. It supports cautious, evidence-informed recommendations rather than supplement hype.

Link: PubMed abstract

 

Recovery starts before the repair

Shoulder surgery and rotator cuff healing place extra demand on the body. Studies in rotator cuff repair patients suggest that poor nutrition markers, including low albumin or a lower GNRI score, are associated with higher risk of retear or higher short-term hospital use. Nutrition is not the only driver of healing--tear size, age, muscle quality, diabetes, smoking, vitamin D status, and rehab all matter--but it is one of the few potentially modifiable factors before surgery.

Pillar 1: Do not under-eat during healing

After surgery, the body shifts into a stress state. It uses energy and amino acids for wound healing, immune function, and tissue repair. Appetite is often reduced after anesthesia and pain medicine, so many patients unintentionally eat less exactly when recovery needs more support. A practical goal is to eat regular meals, include protein at each meal, and avoid skipping meals during the early recovery window.

Pillar 2: Build each meal around protein

Protein provides amino acids needed for muscle, tendon, immune function, and wound healing. Good choices include fish, poultry, eggs, Greek yogurt, cottage cheese, lean meats, soy foods, beans, lentils, and protein-fortified options. Some patients may need protein drinks or amino acid supplements to meet targets, but supplements should be individualized, especially for patients with kidney disease, diabetes, liver disease, digestive issues, or medication interactions.

Pillar 3: Preserve muscle while the shoulder is protected

Rotator cuff repair commonly requires sling use and activity restrictions. Reduced activity can accelerate muscle loss. Orthopedic studies in knee arthroplasty, fracture fixation, hip fracture, and spine surgery suggest that protein, essential amino acids, or conditionally essential amino acids may help reduce early muscle wasting or support recovery in selected patients. The direct shoulder evidence is limited, so this is best framed as supportive recovery nutrition rather than a guaranteed shoulder treatment.

Pillar 4: Correct deficiencies instead of megadosing

Vitamin D deficiency has been associated with higher retear risk and early postoperative pain in some shoulder studies, while systematic review data are mixed. A balanced recommendation is to ask about screening and correction of deficiency, not to take high-dose vitamin D without guidance. Similar caution applies to iron, B12, calcium, and other micronutrients.

Pillar 5: Add color and anti-inflammatory food patterns

A recovery diet should be built around protein plus colorful plants and adequate carbohydrates. Fruits, vegetables, whole grains, legumes, nuts, seeds, olive oil, and fatty fish can provide fiber, vitamin C, polyphenols, omega-3 fats, and other nutrients that support general health and may help regulate inflammation. For most patients, a food-first anti-inflammatory pattern is safer and more durable than relying on pills.

Pillar 6: Use supplements selectively

Supplements are tools, not shortcuts. Collagen/gelatin with vitamin C, whey protein, essential amino acids, HMB, vitamin D, and omega-3s all have some rationale or supportive evidence in related tendon/orthopedic recovery contexts. However, the evidence differs by supplement and procedure. Patients should review supplements with their surgeon, primary care clinician, pharmacist, or dietitian--especially before surgery or when taking blood thinners, diabetes medicines, immune suppressants, or medications that affect kidney/liver function.

Practical food-first checklist for patients

·        Include protein at each meal: examples include fish, poultry, eggs, Greek yogurt, cottage cheese, tofu/soy, beans, lentils, lean meat, or a medically appropriate protein drink.

·        Add color twice daily: fruits and vegetables provide vitamin C, polyphenols, potassium, magnesium, and fiber.

·        Do not fear carbohydrates during healing: whole grains, potatoes, fruit, oats, beans, rice, and other complex carbohydrates help meet energy needs for rehab and tissue repair.

·        Choose healthy fats: olive oil, nuts, seeds, avocado, and fatty fish are useful options in an anti-inflammatory eating pattern.

·        Ask about labs when appropriate: albumin/GNRI, vitamin D, diabetes control, anemia/iron status, and other markers may matter in selected patients.

·        Review supplements before surgery: especially omega-3, herbal products, high-dose vitamins, creatine, HMB, collagen blends, and amino-acid products.

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