Infrapatellar Versus Suprapatellar Nailing for Fractures of the Tibia (INSURT Study): A Multicentered Randomized Controlled Trial

Abstract

Objectives: To compare suprapatellar and infrapatellar tibial nail insertion approaches on postoperative knee pain.

Design: Randomized controlled trial.

Setting: Multicentered academic level 1 trauma centers.

Patient selection criteria: Included were all patients 18-65 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 and Aberdeen Standing Test (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, 1 year, and 2 years postoperatively.

Results: In total, 254 patients were randomized with 128 patients randomized to suprapatellar nailing and 117 patients randomized to infrapatellar nailing. In total, 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 that in 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 1 year (1.4 vs. 2.7 P = 0.0021) postoperatively and was statistically significant but not clinically significant. The Aberdeen Kneeling Test demonstrated that patients who underwent suprapatellar nailing could bear significantly more weight through their operative knee compared with 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), 1 year (49% vs. 45% P = 0.0007), and 2 years (50% vs. 46% P = 0.001) postoperatively.

Conclusions: There was no clinically significant difference between suprapatellar and infrapatellar nailing in terms of VAS knee pain or patient-reported outcome measures. Patients in the suprapatellar cohort could bear more weight through their operative knee up to and including 2 years postsurgery. Patients should be counseled on the ability to kneel and the nail insertion method when considering nail insertion technique.

Level of evidence: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Keywords: Aberdeen kneeling test; anterior knee pain; infrapatellar nail; suprapatellar nail.