gms | German Medical Science

Objectives: Treating chronic neglected Monteggia lesions still is a challenging problem. Open reduction and anular ligament reconstruction may cause scarring and joint stiffness. In addition an ulnar deformity may persist as well as a radial overgrowth can be noted, requiring an ulnar lengthening and flexion osteotomy. Acute lengthening is limited and may lead to delayed union. Using monolateral fixateurs can address this problem, loss of correction and inconvenient traction of the radius may cause problems though. With the hexapod frame a maximum of stability and versatility to continuously reduce the radial head is given.

Methods: The closed reduction of the radial head was achieved by lengthening and angulating the ulna in flexion after proximal, percutaneous corticotomy. The reduction was obtained by a hexapod frame (Taylor Spatial Frame TSF), which was mounted in 180° rotation with proximal referencing. The radius was distally fixed until two weeks after reduction. Series: 8 missed and neglected Monteggia lesions and 1 chronic traumatic subluxation of the radial head, 5 male, 4 female. The average age at trauma was 79 months (46-127), the average delay of treatment was 25 months (4.5-56).

Results and Conclusion: The closed reduction was achieved in all cases without secondary surgical interventions except angulation and distraction adjustments using the TSF software. In average an ulnar lengthening of 15.5 mm (4-26) and a flexion of 25.0° (15-26°) was needed to reduce the radial head and to keep it in place. One case needed additional open reduction due to interposition of a capsular soft tissue formation. The time in frame until consolidation and stable reduction was 96.2 days in average (69-144). The follow up controls were in average 36 months (25-50) showed a persistently stable reduction except for 1 case, which showed a relapse subluxation 3 years after reduction that had to be treated by anular ligament reconstruction. The elbow ROM was in all cases equal or better than before surgery.

The hexapod frame allows precise reduction of the radial head by continuously lengthening and angulating the ulna. Secondary surgical interventions can be avoided in most cases. Pressureless reduction is crucial, requiring a fair amount of lengthening and a solid frame construct. Nevertheless relapses due to changes in the joint configuration during further growth can be observed and will have to be monitored.