Corticosteroid Injections for Rotator Cuff Injury and Tendonitis
A single subacromial injection of corticosteroid (such as Solu-Medrol/methylprednisolone) with local anesthetic is supported for short-term pain and functional improvement in rotator cuff injuries and tendonitis, but muscle relaxers have no established role in this condition. 1
Corticosteroid Administration
Evidence Supporting Use
- Moderate evidence from the American Academy of Orthopaedic Surgeons supports a single subacromial corticosteroid injection combined with local anesthetic for short-term improvement in both pain and function. 1
- Subacromial injections demonstrate a relative risk of 3.08 for symptom improvement, with a number needed to treat of 3.3 patients to achieve one improvement. 2
- Higher doses (≥50 mg prednisone equivalent) show superior efficacy with a relative risk of 5.9 for improvement. 2
- Corticosteroids appear more effective than NSAIDs alone, with a relative risk of 1.43 and number needed to treat of 2.5. 2
Critical Limitations and Warnings
- Limit to a single injection only—multiple repeated corticosteroid injections are not supported by evidence and should be avoided. 3
- A single dose of methylprednisolone significantly weakens both intact and injured rotator cuff tendons at one week, reducing maximum load from 37.9 N to 27.5 N and maximum stress from 18.1 MPa to 13.6 MPa. 4
- Corticosteroids initiate a structural injury response in uninjured tendons, increasing the type-III to type-I collagen ratio more than fourfold, equivalent to actual structural damage. 5
- These biomechanical effects are transient, returning to baseline by three weeks, but create a critical vulnerability window. 4
- The overall failure rate of conservative treatment including corticosteroid injection is approximately 40% at 22 months follow-up. 6
Muscle Relaxers
There is no evidence supporting the use of muscle relaxers for rotator cuff injury or tendonitis. The guidelines from the American Academy of Orthopaedic Surgeons do not mention muscle relaxers as part of the treatment algorithm for rotator cuff pathology. 1, 3, 7
- Rotator cuff injuries involve tendon pathology, not primary muscle spasm requiring muscle relaxant therapy.
- The conservative management algorithm focuses on NSAIDs, exercise therapy, and selective corticosteroid injection—not muscle relaxers. 3, 7
Recommended Treatment Algorithm
First-Line Management
- NSAIDs combined with exercise programs focusing on rotator cuff strengthening and scapular stabilization. 3, 7
- Activity modification to avoid aggravating movements. 7
- Paracetamol can be added to NSAIDs for enhanced pain control. 3
Second-Line Intervention (If First-Line Fails)
- Single subacromial corticosteroid injection (e.g., 1 cc Depo-Medrol 40 mg with 1 cc lidocaine 2%) for short-term relief. 1, 8
- Inject under ultrasound guidance when possible for optimal placement. 8
- Warn patients about the 1-week period of tendon weakness and avoid heavy lifting during this time. 4
Third-Line Options
- More intensive supervised physical therapy program. 7
- Consider hyaluronic acid injections (limited evidence). 1, 7
- PRP injections show similar or slightly better results than corticosteroids for pain and range of motion, particularly if corticosteroids are contraindicated, though evidence is limited. 8, 1
Common Pitfalls to Avoid
- Do not use multiple corticosteroid injections—this increases risk of tendon rupture without additional benefit. 3, 5, 4
- Do not prescribe muscle relaxers—they have no role in rotator cuff pathology and may cause unnecessary sedation and side effects without addressing the underlying tendon problem.
- Do not use opioids as first-line treatment—reserve strictly for rescue analgesia when other methods fail. 3
- Do not neglect exercise therapy, which forms the cornerstone of conservative management and should not be replaced by injections alone. 7
- Avoid heavy loading activities for at least 2-3 weeks after corticosteroid injection due to transient tendon weakening. 4