Ketorolac Injection Into or Around Tendons: Safety Considerations
Do not inject ketorolac directly into tendon substance. While ketorolac can be safely administered peritendinously (around tendons), direct intratendinous injection should be avoided due to theoretical concerns about tendon integrity, though the evidence suggests ketorolac may be safer than corticosteroids in this regard.
Key Safety Principles
Direct Intratendinous Injection
- Avoid injecting directly into the tendon substance itself, as this is the primary concern with any injectable agent 1.
- The American Family Physician guidelines specifically warn that injections into tendon substance may cause deleterious effects, though this warning primarily addresses corticosteroids 1.
- The primary risk with direct tendon injection is tendon rupture, which is well-documented with corticosteroids but less clearly established with NSAIDs like ketorolac 2.
Peritendinous (Around Tendon) Injection
- Peritendinous ketorolac injection appears to be safer than direct intratendinous injection and may be used for conditions like tendinopathy 3, 4.
- Research demonstrates that ketorolac exposure to tendons shows better safety profiles compared to corticosteroids, with no evidence of tendon necrosis 3.
- Animal studies show that tendons exposed to ketorolac demonstrated increased load and energy to failure without material stiffness changes, suggesting preserved tendon integrity 3.
Evidence Supporting Ketorolac Safety Near Tendons
Comparative Safety Data
- In vitro studies show ketorolac maintains tenocyte viability, unlike methylprednisolone which significantly decreases cell viability 5.
- Tenocyte viability at 120 hours was significantly higher with ketorolac treatment (52,025 ± 17,307) compared to methylprednisolone (3,934 ± 1,791) 5.
- Gross tendon adhesions were observed more frequently with corticosteroid treatment than with ketorolac or saline in animal models 3.
Clinical Applications
- Ketorolac injections have demonstrated efficacy for subacromial bursitis, adhesive capsulitis, and joint osteoarthritis—conditions where peritendinous structures are involved 4.
- Ketorolac represents a viable alternative to corticosteroid injections for musculoskeletal conditions, particularly in patients where systemic glucocorticoid effects are concerning 4.
Critical Warnings from FDA Labeling
Hemorrhage Risk
- Ketorolac affects platelet aggregation and hemostasis, which is particularly relevant in the perioperative or peri-injection setting 6.
- Postoperative hematomas and wound bleeding have been reported with ketorolac use, so injection should be undertaken with caution when hemostasis is critical 6.
- Patients on anticoagulants have increased bleeding risk with concurrent ketorolac use 6.
Duration Limitations
- Total duration of ketorolac use (all routes combined) should not exceed 5 days 6.
- Even short-term therapy carries risks, particularly for GI bleeding and renal complications 6.
Practical Injection Guidelines
Technique Considerations
- Target peritendinous tissues (bursa, tendon sheath) rather than tendon substance 1, 3.
- Use ultrasound guidance when available to ensure accurate placement and avoid direct intratendinous injection 2.
- Consider the 5-day maximum duration limit when planning injection therapy 6.
Patient Selection
- Avoid in patients with coagulation disorders or those on anticoagulation therapy 6.
- Use caution in elderly patients (≥65 years) who require reduced dosing 6.
- Contraindicated in patients with advanced renal impairment 6.
Common Pitfalls to Avoid
- Do not confuse peritendinous with intratendinous injection—the former is acceptable while the latter should be avoided 1, 3.
- Do not exceed 5 days of total ketorolac therapy across all administration routes 6.
- Do not use in the immediate perioperative period when hemostasis is critical, as wound bleeding risk is increased 6.
- Avoid combining with other agents that affect hemostasis without careful consideration of bleeding risk 6.