Polyaxial Locking Plates in Treating Distal Humeral Fractures: a Comparative Randomized Trial for Clinical Outcome

Before study initiation the approval of the local ethics committee of (Trial Number 253/14) was obtained. The clinical trial included 20 patients with fractures of the distal humerus recruited from a level-one university trauma centre. Patient recruitment was conducted between 03/2014 and 12/2015. Fractures of the distal humerus, as defined by the AO classification system (AO 13-A1 - AO 13-C3), were included in this study as they were identified by the treating surgeon being applicable for locking plate treatment and after written informed consent of the patients was obtained. All patients were randomized following a randomization plan (Randlist, DatInf GmbH, Tübingen, Germany) for either being treated with the DePuy Synthes VA-LCP 2.7/3.5 mm (DePuy Synthes, Umkirch, Germany) or with the Medartis Aptus Elbow system 2.0/3.8 mm (Medartis, Basel, Switzerland). Both systems include anatomically preshaped, polyaxial angular stable locking plates in various sizes. Angle stable screw positioning with the freedom of +/- 15° off-axis screw placement gives the surgeon a large variety in both systems.

The inclusion criteria involve all patients from the age of 18 to 95 years who suffered from a distal humeral fracture (AO 13-A1 - AO 13-C3) that had to undergo operative treatment. The exclusion criteria involve all under-aged patients (< 18 years), pregnant patients and patients with a mental disorder as well as patients under comprehensive legal support. In addition, pathological fractures had been excluded from the study.

Surgical technique

All patients were operated by experienced upper extremity surgeons. The mean interval between injury and operation was 2.4 days (range 0-12 days). General anaesthesia was used in all cases and a single dose of 1.5 mg cephalosporin was given preoperatively for prophylaxis. Patients were positioned in prone position with the injured arm on a radiolucent, small padded arm holder. Under tourniquet control, the posterior approach (Bryan-Morrey) to the distal humerus was performed in all cases. Additional olecranon osteotomy was performed in 7 cases (3x DePuy Synthes vs. 4x Medartis Aptus Elbow) presenting with AO type 13 C2 and AO type 13 C3 fractures. Postoperatively, physiotherapy was initiated using the same rehabilitation protocol for both groups. Passive and active assisted ROM was permitted immediately without limitations, while weight bearing was restricted for 6 weeks.

Follow-up evaluation