[Translated article] The use of an anatomical implant compared to a straight LCP decreases extraction in posterior humeral MIPO.

Purpose: Posterior MIPO approach in the humerus has been described by using a 4.5mm LCP plate. Although straight plates have shown good results, they have not been designed to adapt to the distal humeral metaphysis. The goal of the study was to test the null hypothesis that there is no difference in hardware removal after posterior MIPO with either a straight or a pre-contoured plate.

Methods: Patients older than 18 years, who had suffered mid-distal humeral shaft fracture, were treated by a posterior MIPO technique with a locking plate and had a minimum of 12-month follow-up were retrospectively included. Patients were separated into: group 1 (LCP 4.5mm straight plate); and group 2 (3.5mm anatomically shaped plate). Clinical and radiological evaluations were performed in the postoperative period. Patient-reported outcomes and the need of hardware removal because of pain were assessed.

Results: Sixty-seven patients fulfilled the inclusion criteria. Twenty-seven patients in group 1 and 40 in group 2. No patient was lost to follow-up. There were no statistical differences between in patient reported outcomes measures. All the fractures healed. Within group 1, 18% (95%CI: 6-38%) of the patients required implant removal while in group 2 this incidence was 0% (95%CI: 0-9%) (P 0.009).

Conclusion: These results suggest that the use of a 4.5mm LCP compared to an anatomical 3.5mm LCP in posterior MIPO of the humerus generates greater discomfort and therefore leads to a 18% increase in the risk of implant removal.