title: Comparison of accuracy of anterior and superomedial approaches to shoulder injection: an experimental study.
abstract: BACKGROUND
  We aimed to compare the accuracy between the standard anterior technique of shoulder injection and the new superomedial technique modified from Neviaser arthroscopic portal placement. Intra-articular placement, especially at the long head of biceps (LHB) tendon, and needle depth were evaluated.
  
  
  METHODS
  Fifty-eight patients (ages 57 ± 10 years) requiring shoulder arthroscopy in the beach-chair position were recruited. Needle punctures for both techniques were performed by an experienced sports medicine orthopedist. Patients were anesthetized, and the shoulder placed in the neutral position. A single needle was passed through the skin, with only one redirection allowed per trial. The superomedial technique was performed, then the anterior technique. Posterior-portal arthroscopy determined whether needle placement was inside the joint. The percentage of intra-articular needle placements for each technique defined accuracy. When inside the joint, the needle's precise location was determined and its depth measured. A marginal χ(2) test compared results between techniques.
  
  
  RESULTS
  The superomedial technique was significantly more accurate than the anterior technique (84% vs. 55%, p < 0.05). For superomedial versus anterior attempts, the LHB tendon was penetrated in 4% vs. 28% of patients, respectively, and the superior labrum in 35% vs. 0% of patients, respectively; the needle depth was 42 ± 7 vs. 32 ± 7 mm, respectively (all p < 0.05).
  
  
  CONCLUSIONS
  The superomedial technique was more accurate, penetrating the LHB tendon less frequently than the standard anterior technique. A small-diameter needle was needed to minimize superior labral injury. The superomedial technique required a longer needle to access the shoulder joint.
authors.affiliation: Department of Orthopaedic Surgery, Faculty of Medicine, Thammasat University Hospital Klong-Nueng, Klong-Luang, Pathumthani 12120 Thailand.
authors.forename: Bancha
authors.initials: B
authors.lastname: Chernchujit
authors.affiliation: Department of Orthopaedic Surgery, Faculty of Medicine, Thammasat University Hospital Klong-Nueng, Klong-Luang, Pathumthani 12120 Thailand.
authors.forename: Nutthapon
authors.initials: N
authors.lastname: Zonthichai
keywords: Accuracy; Neviaser; Shoulder injection; Superomedial approach