MIPO helical pre-contoured plates in diaphyseal humeral fractures with proximal extension. Surgical technique and results.

INTRODUCTION: The aim of this study was to determine the feasibility of applying the MIPO technique with a helical-shaped plate in the treatment of humeral shaft fractures with proximal extension. PATIENTS AND METHODS: We present an observational prospective study of patients with a humeral shaft fracture involving the proximal humerus fixed with a long proximal humerus polyaxial locking plate with an anterior curvature and helical shape (ALPS® Zimmerbiomet, Warsaw, Indianapolis, USA), using a MIPO technique. Between January 2017 and July 2020, 15 patients were treated at our institution. Proximally a 4-5 cm anterolateral transdeltoid approach was made. And distally, a 5-7 cm incision was made 4 cm proximal to the elbow crease. At each follow-up, radiographs were taken to evaluate fracture healing. Funtional scales were applied to evaluate clinical results. RESULTS: Ten women and five men were included, with a mean age of 62 yo (range 26-86). All but one fracture healed uneventfully. The mean time to union was 28 weeks (range 12-48 weeks). Two out of 15 patients presented complications (an atrophic nonunion and a peri­implant distal fracture). None of the patients had a nerve palsy prior neither after the surgery. No other complications, including infection, were registered during follow-up. Shoulder range of motion showed the following means: abduction of 147° (range 50°-180°), anterior flexion of 144° (range 80°-180°), external rotation of 77,5 ° (range 70°-80°) and internal rotation of 54.5° (range 45°-60°). All patients recovered their pre-fracture elbow range of motion. All patients presented less than 10° of angular deviation in varus/valgus or ante/recurvatum after the surgical procedure. At the end of the follow-up, all final functional scores were "good" or "excellent": mean Constant-Murley score was 72 ± 13 (range 38-91), ASES score was 73 ± 12 (range 41-88), UCLA shoulder scale was 30 ± 3,5 (range 10-35), and Q-DASH score was 16.5 ± 0,11 (range 4-57). CONCLUSION: When applied correctly, the treatment of diaphyseal humeral fractures involving the proximal humerus using a polyaxial locking helical plate with a MIPO technique is a reliable treatment method. It has high union rates with low complications.