The accuracy of subacromial injections: a prospective randomized magnetic resonance imaging study

Arthroscopy. 2006 Mar;22(3):277-82. doi: 10.1016/j.arthro.2005.12.019.


Purpose: To assess the accuracy of shoulder infiltrations in the subacromial bursa (SAB) by a posterior or an anteromedial approach. Magnetic resonance imaging (MRI) and clinical outcome were used for evaluation.

Type of study: A prospective randomized study.

Methods: Thirty-three patients (22 women, 11 men; average age, 46 years; range, 25 to 64 years) with clinical signs of subacromial impingement were infiltrated with a mixture of bupivacaine, methylprednisolone, and gadolinium-DTPA directly followed by MRI to determine the actual site of injection. The SAB was randomly infiltrated posteriorly (n = 17) or anteromedially (n = 16). Injection confidence of the surgeon and body-mass index of the patient were recorded. Follow-up consisted of the Constant Score, Simple Shoulder Test, and visual analog scale score for pain taken within 24 hours and 6 weeks after infiltration.

Results: Thirteen injections (76%) were in the SAB with a posterior approach and 10 (69%) with an anteromedial approach. Many surrounding structures were hit as well, especially the rotator cuff. A positive correlation between the injection confidence of the orthopaedic surgeon and the MRI was found in 66%. Only injection of the SAB alone resulted in a significant decrease of the pain (P = .004) and an increase in the functional scores. Injection in the bursa and rotator cuff muscle showed a significant increase in pain (P = .032) but no change in clinical scores. The body mass index had no influence on the scores.

Conclusions: Injections in the SAB are inaccurate, despite the confident feeling of the clinician. The finding that many different structures can be infiltrated with 1 injection can create both false-positive and -negative results.

Level of evidence: Level II.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Acromion*
  • Adult
  • Anesthetics, Local / administration & dosage*
  • Anesthetics, Local / therapeutic use
  • Anti-Inflammatory Agents / administration & dosage*
  • Anti-Inflammatory Agents / therapeutic use
  • Bupivacaine / administration & dosage*
  • Bupivacaine / therapeutic use
  • Bursa, Synovial*
  • Contrast Media / administration & dosage
  • False Negative Reactions
  • False Positive Reactions
  • Female
  • Gadolinium DTPA / administration & dosage
  • Humans
  • Injections, Intralesional*
  • Magnetic Resonance Imaging*
  • Male
  • Methylprednisolone / administration & dosage*
  • Methylprednisolone / therapeutic use
  • Middle Aged
  • Prospective Studies
  • Rotator Cuff Injuries
  • Shoulder Impingement Syndrome / complications*
  • Shoulder Pain / diagnosis*
  • Shoulder Pain / drug therapy
  • Shoulder Pain / etiology


  • Anesthetics, Local
  • Anti-Inflammatory Agents
  • Contrast Media
  • Gadolinium DTPA
  • Methylprednisolone
  • Bupivacaine