Comparison of the spread pattern of medial-to-lateral and lateral-to-medial rotator interval injections: A cadaveric study.

OBJECTIVE

Rotator interval (RI) corticosteroid injections are used to alleviate pain associated with adhesive capsulitis, though the pattern of injectate spread remains unclear. The purpose of this anatomical study was to assess the staining patterns of intra-articular, intracapsular/extrasynovial, and pericapsular structures of the glenohumeral joint following medial-to-lateral and lateral-to-medial RI injections.

DESIGN

Ten cadaveric specimens were injected with a methylene blue dye injectate: five using a medial-to-lateral RI injection technique and five using a lateral-to-medial RI injection technique. Serial dissection was performed to assess the staining of intra-articular, intracapsular/extrasynovial, and pericapsular structures. The frequency of capture and degree of staining were compared between injection groups.

RESULTS

The lateral-to-medial injection resulted in the capture of all intra-articular; intracapsular/extrasynovial; and pericapsular structures, whereas the medial-to-lateral injection did not consistently stain all structures. Intracapsular/extrasynovial structures (superior glenohumeral ligament and the long head of biceps tendon) were more darkly stained in the lateral-to-medial group, and pericapsular structures (supraspinatus tendon and coracohumeral ligament) were more darkly stained in the medial-to-lateral group.

CONCLUSION

The frequency of capture and degree of staining of intra-articular, intracapsular/extrasynovial, and pericapsular structures of the glenohumeral joint differed between medial-to-lateral and lateral-to-medial RI injection techniques, which may influence outcomes in pain management for adhesive capsulitis.