Analysis of long term results for forearm pronation osteotomy in children with congenital brachial plexus injury

Secondary problems that may develop due to congenital brachial plexus injury cause inadequacies in daily living activities. In children with total plexus injury, supination contractures seen as a result of power imbalance between pronator and supinator muscle groups with flaccid paralysis cause limitations in terms of hand use in daily life. During the follow-up period after birth, problems such as retraction of the interosseous membrane, subluxation of the distal radioulnar joint and dislocation of the radius head may be observed. Biceps re-routing, interosseous membrane release or derotation osteotomy in the pronation direction are performed for pronation insufficiency. The main goal of these surgeries is to restore auxiliary hand function to the affected hand. The first aim of our study is to investigate the changes in active/passive range of motion, forearm rotation posture at rest, Active Movement Scale(AMS) scores, Modified Mallet Scale forearm position at rest, Raimondi Hand Scale results, and Brachial Plexus Outcome Measure(BPOM) scores evaluating the activity domain, both in the body structure and function domain of the osteotomy for pronation gain and the structured targeted physiotherapy program. The second aim of our study is to compare the only radius and combined (radius and ulna) derotation surgical groups with all parameters in forearm derotation osteotomies. This study is a retrospective analysis of the results of forearm derotation osteotomy for forearm supination contracture in 37 children aged 5-18 years with total plexus injury who were followed up with a diagnosis of congenital brachial plexus injury in Hacettepe University Faculty of Medicine, Department of Orthopedics and Traumatology between 2018 and 2023. Patients were divided into two according to osteotomy techniques: only radius derotation(24 patients) and combined derotation(13 patients). The data obtained as a result of the study were analyzed and collected separately both in all patients and in the 2 surgical groups. When joint movements were analyzed; an increase of 45º[(40º)-(47.5)º] in passive pronation, a decrease of 20º[(15º)-(25º)] in passive supination, an increase of 10º[(5º)-(15º)] in active pronation, and a decrease of 10º[(5º)-(15º)] in active supination were observed(p<0.001). A change of 45º[35º-60º] in the direction of pronation was detected in the forearm rotation posture at rest(p<0.001). The pronation score according to AMS increased from 1.0[(0.0)-(2.0)] before surgery to 2.0[(1.0)-(3.0)] after surgery(p<0.001). Raimondi Hand Scale scores increased from 2.0[(1.5)-(3.0)] before surgery to 3.0[(2.0)-(4.0)] after surgery(p<0.001). According to the Modified Mallet Scale, 48.6% of the patients could be turned to pronation and there was an increase in BPOM scores in the activity area(p<0.001). All evaluations were also compared in terms of surgical groups. Passive wrist extension, active elbow flexion and AMS supination scores were higher in the combined derotation group compared to the only radius derotation group(p<0.01). In addition,no difference was observed between the groups in all other parameters(p>0.05). As a result of this study,an increase in pronation movement and activity levels of the affected upper extremity were observed after both derotation osteotomies. It is aimed to use the affected hand as an "assisting hand" in children with total plexus damage, and this level is determined as 3 on the Raimondi Hand Scale. It has been determined that the "assisting hand" function can be achieved with both surgical options and the subsequent structured goal-oriented physiotherapy process. Keywords: Congenital Brachial Plexus Injury, supination contracture, derotation osteotomy, pronation gain, Brachial Plexus Outcome Measurement (BPOM)