External Rotation Predicts Outcomes After Closed Glenohumeral Joint Reduction With Botulinum Toxin Type A in Brachial Plexus Birth Palsy.

BACKGROUND

Few studies have investigated outcomes after adjunct botulinum toxin type A (BTX-A) injections into the shoulder internal rotator muscles during shoulder closed reduction and spica cast immobilization in children with brachial plexus birth palsy. The purpose of this study was to report success rates after treatment and identify pretreatment predictors of success.

METHODS

Children with brachial plexus birth palsy who underwent closed glenohumeral joint reduction with BTX-A and casting were included. Minimum follow-up was 1 year. Included patients did not receive concomitant shoulder surgery nor undergo microsurgery within 8 months. Records were reviewed for severity of palsy, age, physical examination scores, passive external rotation (PER), and subsequent orthopaedic procedures (repeat injections, repeat reduction, shoulder tendon transfers, and humeral osteotomy). Treatment success was defined in 3 separate ways: no subsequent surgical reduction, no subsequent closed or surgical reduction, and no subsequent procedure plus adequate external rotation.

RESULTS

Forty-nine patients were included. Average age at time of treatment was 11.5 months. Average follow-up was 21.1 months (range, 1 to 9 y). Thirty-two patients (65%) required repeat reduction (closed or surgical). Only 16% of all patients obtained adequate active external rotation without any subsequent procedure. Increased PER (average 41±14 degrees, odds ratio=1.21, P=0.01) and Active Movement Scale external rotation (average 1.3, odds ratio=2.36, P=0.02) predicted optimal treatment success. Limited pretreatment PER (average -1±17 degrees) was associated with treatment failure. Using the optimal definition for success, all patients with pretreatment PER>30 degrees qualified as successes and all patients with PER<15 degrees were treatment failures.

CONCLUSIONS

Pretreatment PER>30 degrees can help identify which patients are most likely to experience successful outcomes after shoulder closed reduction with BTX-A and cast immobilization. However, a large proportion of these patients will still have mild shoulder subluxation or external rotation deficits warranting subsequent intervention.

LEVEL OF EVIDENCE: Level IV-therapeutic.