Humeral Intramedullary Nailing Utilizing the Minimally Invasive Rotator-Interval Technique (MIR-IT) Improves Shoulder PROMs.

Abstract

To assess whether patients treated with a Minimally Invasive Rotator-Interval Technique (MIR-IT) versus the traditional technique of splitting the rotator cuff (RTCS) for intramedullary nailing of humeral shaft fractures resulted in comparable post-operative clinical and patient-reported outcomes (PROM). Design: Retrospective Cohort Study. Level 1 Trauma Center. Patients >18yo with humeral shaft fractures (AO/OTA 12A-C) treated with IMN between 2015 and 2022. The primary outcome was differences in PROMs (ASES, Quick DASH, and Oxford Shoulder Score) between the MIR-IT and RTCS techniques. Secondary outcome measures included differences in rates of nonunion, superficial and deep surgical infections, wound dehiscence and iatrogenic nerve palsy between the two techniques. Seventy-one patients underwent humeral IMN (MIR-IT - 39; RTCS - 32). Fifty-five patients (MIR-IT- 30; RTCS-25) had radiographic and clinical follow up to union. Mean follow up was 7.5 months (range: 3.1-16.8 months). Patients did not vary significantly with regards to age (MIR-IT: 54.4 ± 22.4; RTCS: 55.1 ± 18.5 years, p=0.896), and gender (Males- MIR-IT: 46.7%, RTCS: 44%, p=0.843). There were no significant differences in nonunion (7.4% vs 4.0% p=1.0), superficial infection (3.6% vs 4% p=1.0) or iatrogenic nerve palsy (3.6% vs 4.0% p=1.0) between the MIR-IT and RTCS groups. There were no deep infections or wound dehiscences in either group. Forty-two patients had PROMs (MIR-IT -21; RTCS -21). Average time to PROMs collection was 35.7 months (MIR-IT: 34.2 months, RTCS: 37.1 months, p=0.682). There were significantly better ASES scores (82.7 vs 71.6 p=.015), Quick DASH scores (9.7 vs 21.0 p=.011) and Oxford Shoulder Scores (39.3 vs 33.9 p=.042) amongst patients treated with the MIR-IT. Humeral IMN utilizing the MIR-IT resulted in better shoulder PROMs compared to the RTCS technique, with similarly low surgical complication rates. Therapeutic Level II.