Infrapatellar vs suprapatellar nailing for fractures of the tibia (INSURT study): A multicentered randomized controlled trial

OBJECTIVES: To compare suprapatellar and infrapatellar tibial nail insertion approaches on post-operative knee pain METHODS: Design : Randomized controlled trial Setting: Multi-centered academic level 1 trauma centers Patient Selection Criteria: Included were all patients 18 to 65 years of age with nailing OTA/AO type 42 and 43A fractures amenable to and indicated for repair with reamed intramedullary nailing Outcome Measures and Comparisons: Patients were randomized to receive a tibial intramedullary nail through either a suprapatellar or infrapatellar approach. The primary outcome was the visual analog scale (VAS) for knee pain after kneeling for 60 seconds. The study was designed to have 80% power to detect a 1.6-point difference in the VAS for pain on kneeling, which was considered clinically significant. Secondary outcomes included the Aberdeen Kneeling Test (AKT) and Aberdeen Standing Test (AST) (objective measures of weight-bearing capacity while kneeling and standing), Lysholm score, EQ-5D score, and Work Productivity and Activity Impairment Questionnaire (WPAI). The outcomes were recorded at 6 weeks, 4 months, 6 months, one year, and two years post-operatively. RESULTS: 254 patients were randomized with 128 patients randomized to suprapatellar nailing and 117 patients randomized to infrapatellar nailing. 96 patients (68.8% male) in the suprapatellar group (mean age 42.4 years, range 18-60 years) and 93 patients (69.2% male) in the infrapatellar group (mean age 38.8 years, range 19-52 years) completed 2-year follow-up. The VAS after kneeling for 60 seconds in the suprapatellar group was lower than the infrapatellar group at 6 weeks (4.1 vs 5.2 p=0.012), 4 months (2.8 vs 4.1 p=0.0003), 6 months (2.2 vs 3.2 p=0.0041), and one year (1.4 vs 2.7 p=0.0021) post-operatively and was statistical significant but not clinically significant. The AKT demonstrated that patients who underwent suprapatellar nailing could bear significantly more weight through their operative knee compared to the infrapatellar treatment group at 6 weeks (36% vs 27% p=0.0004), 4 months (45% vs 41% p=0.0012), 6 months (47% vs 43% p=0.001), one year (49% vs 45% p=0.0007), and two years (50% vs 46% p=0.001) post-operatively. CONCLUSIONS: There was no clinically significant difference between suprapatellar and infrapatellar nailing in terms of VAS knee pain or PROMs. Patients in the suprapatellar cohort could bear more weight through their operative knee up to and including 2 years post-surgery. Patients should be counseled on the ability to kneel and the nail insertion method when considering nail insertion technique. LEVEL OF EVIDENCE: Level I