Abstract
Introduction: Upper root injuries (C5–C6±C7) account for 75 % of all obstetric brachial plexus palsies (OBPP). Among them, about thirty percent develop a medial contracture of the shoulder due to an imbalance between strong internal rotators and weak external rotators. This causes glenohumeral deformities. To decrease the internal contracture it had been proposed either to release the subscapularis (Sever procedure) or to perform a capsular release (Fairbank procedure). Arthroscopic capsular release was proposed in young patient to reduce the medial contracture.
Material & methods: Six children with an average age of 23 months and 1 case aged 12 years old, had a medial contracture of the shoulder secondary to a C5–C6 ( 3 cases) or C5–C7 (4 cases) obstetrical palsy. An arthroscopic evaluation of the deformities was performed in 3 cases. Next a surgical subscapularis release was applied in association with a latissimus dorsi transfer.
An arthroscopic evaluation of the joint associated with an arthroscopic capsular release (release of the coracohumeral ligament) was performed in 4 cases. In addition, the latissimus dorsi was transfered. Pre and Post operative passive external rotation were measured in degrees in R1 position.
Pre and post operative medial rotation were evaluated according to the Mallet classification. A comparative evaluation of the glenohumeral deformities were performed between pre-operative MRI and arthroscopic results.
Results: An arthroscopic evaluation of the glenohumeral joint was performed in 6 cases. In one case the arthroscopic evaluation could not be performed. In the 6 cases, arthroscopy confirmed the MRI lesion : 3 posterior subluxations, 1 posterior luxation and 2 normal joints. The subscapularis release allowed an increase in the passive lateral rotation of an average of 50°. However, a decrease of 1 point in the medial rotation was noted according to Mallet evaluation. The coracohumeral ligament arthroscopic release allowed an increase in the passive lateral rotation of an average of 60° without decreasing the passive medial rotation. Whatever the method used, a reduction of the subluxation of the glenohumeral joint was obtained.
Discussion & Conclusion: Medial contracture of the shoulder may begin in the first two years of life and an early reduction with muscular release and transfers was proposed. However, the precise nature of the progressive limitation of the external passive rotation remains unclear. Is the limitation due to a contracture of the medial rotators or a capsular retraction or a combination of both? Harryman demonstrated the role of the rotator interval capsule and coracohumeral ligament in limiting the external rotation. Our hypothesis was that capsular retraction occurred before the muscular contracture. As a result we decided to perform a capsular release in patients under 24 months. The results on the passive external rotation were similar with both methods. Although, the technique of an arthroscopic release was difficult and demanding, it appears that this technique is beneficial as it allows an evaluation of the joint deformity and treatment of the contracture in the same time.
Arthroscopic release is a safe but demanding technique which allows an increase in the external passive rotation in OBPP. It should be noted that this technique requires a significant practice.
The abstracts were prepared by Editorial Secretary, Mr Robin W Paton. Correspondence should be addressed to BSCOS at the Royal College of Surgeons, 35– 43 Lincoln’s Inn Fields, London WC2A 3PN
