Distal third diaphyseal humeral fractures treated with posterior minimally invasive plate osteosynthesis (MIPO)

To describe the technique, safety, and clinical outcomes of posterior minimally invasive plate osteosynthesis (MIPO) in patients with distal third diaphyseal humeral fractures, highlighting its advantages over traditional approaches. This retrospective case series included four patients with distal third diaphyseal humeral fractures (AO/OTA 1.2.A-c and 1.2.B-c) treated using posterior MIPO. Patients aged 18–70 years, without prior radial nerve injuries, were included. The procedure involved two small longitudinal incisions, nerve protection, and submuscular plate placement with indirect reduction techniques. Functional outcomes were assessed using VAS, DASH, Constant Score, and MEPI at 1 month, 6 months, and 12 months postoperatively. Radiographic alignment and complications were also evaluated. Four patients (mean age 45 years) were treated. The average surgical time was 1 h 30 min. No infections or cases of nonunion were observed. Only one patient developed transient radial nerve paresthesia, which resolved completely within 4 weeks. Functional outcomes were excellent at final follow-up (12–36 months): VAS : 0–2; DASH : 0–5; Constant Score : 95–100; MEPI : 90–100. Radiographs demonstrated fracture union at an average of 4 months, with residual varus angulation between 0° and 5° without functional impact. Posterior MIPO is a safe and effective technique for distal third diaphyseal humeral fractures, offering excellent functional outcomes, low complication rates, and reduced soft tissue disruption. Proper identification and protection of the radial nerve are critical to success.