Is the Anterior Injection Approach Without Ultrasound Guidance Superior to the Posterior Approach for Adhesive Capsulitis of the Shoulder? A Sequential, Prospective Trial
Authors: Rijs Zeger , de Groot Pieter C. J. , Zwitser Eline W. , Visser Cornelis P. J. 
Published: May 2021

Abstract

Background
Shoulder injections for conditions such as adhesive capsulitis are commonly performed and can be administered through image-based or landmark-based injection approaches. Ultrasound-guided injections are widely used and accurate because ultrasound allows real-time visualization of the needle and injected contrast. Landmark-based injections would be advantageous, if they were accurate, because they would save the time and expense associated with ultrasound. However, few prospective studies have compared well-described landmark-based shoulder injection techniques without ultrasound.

Question/purpose
Using anatomic landmarks, and without using ultrasound, is the accuracy of glenohumeral injection for adhesive capsulitis greater via the posterior approach or via a new anterior approach?

Methods
Between 2018 and 2020, we treated 108 patients potentially eligible for adhesive capsulitis treatment. These patients had clinical symptoms of aggravating shoulder pain with a duration of less than 4 months and passively impaired, painful glenohumeral ROM. Due to the exclusion of patients with other shoulder conditions (full-thickness rotator cuff ruptures and posttraumatic stiffness), 95 patients received an injection in this sequential, prospective, comparative study. Between 2018 and 2019, 41 patients (17 males and 24 females; mean age 52 ± 5 years; mean BMI 24 ± 3 kg/m2) were injected through the posterior approach, with the acromion as the anatomical landmark, during the first part of the study period. After that, between 2019 and 2020, 54 patients (20 males and 34 females; mean age 54 ± 4 years; mean BMI 23 ± 3 kg/m2) received an injection through a new anterior approach, with the acromioclavicular joint as the anatomic landmark, during the second part of the study period. Injections via both approaches were administered by two experienced shoulder specialists (both with more than 10 years of experience). Both specialists had experience with the posterior approach before this study, and neither had previous training with the new anterior approach. Injections contained a corticosteroid, local anaesthetic, and contrast medium. Radiographs were taken within 20 minutes after the injection, and a radiologist blinded to the technique determined accuracy. Accurate injections were defined as having contrast fluid limited to the glenohumeral joint, while inaccurate injections displayed leakage of contrast fluid into the soft tissue or subacromial space. All of the enrolled patients were analyzed.

Results
In the group with the posterior approach, the accuracy was 78% (32 of 41) in contrast to 94% (51 of 54, odds ratio 0.21 [95% CI 0.05 to 0.83]; p = 0.03) in patients with the new anterior approach.

Conclusion
The new anterior approach without the use of ultrasound was more accurate than the posterior approach. In fact, it was nearly as accurate as previously published ultrasound-guided approaches. We recommend using the new anterior approach for intraarticular glenohumeral injections instead of ultrasound-guided injections because it will save time and costs associated with ultrasound. Still, the clinical effects (anxiety, pain, functional outcome, and adverse events) of the new anterior approach should be compared with ultrasound-guided injections in a randomized study.

Level of Evidence
Level II, therapeutic study.