A Biomechanical Comparison of Gluteus Medius Repair With and Without Iliotibial Band Autograft Augmentation

Abstract

Background:

Gluteus medius tears are an increasingly recognized cause of lateral hip pain in active individuals, yet no gold standard repair technique has been established, and failure and retear rates remain high. Iliotibial band (ITB) graft augmentation is a validated option in rotator cuff and hip labral repairs for stronger repair construct, but its biomechanical utility in gluteus medius repairs has not been investigated.

Hypothesis:

It was hypothesized that ITB-augmented gluteus medius repairs would demonstrate superior ultimate load to failure and increased repair stiffness as compared with nonaugmented repairs.

Study Design:

Controlled laboratory study.

Methods:

Fourteen unpaired fresh-frozen cadaveric hemipelvises with intact gluteus medius tendons were randomized into ITB-augmented and nonaugmented groups and tested biomechanically with a tensile testing machine. Native stiffness was assessed as follows: 10-N preload for 2 minutes, 150 cycles at 0.8 Hz from 10 to 125 N to simulate early partial weightbearing, followed by a quasistatic load to 60 N at 1 mm/s. Tendons were then elevated from their anatomic footprint on the greater trochanter and repaired using double-row suture bridge configurations, with augmented repair incorporating ITB graft fixation. After preconditioning (10 N for 2 minutes, 150 cycles at 0.8 Hz from 10 to 125 N to simulate early partial weightbearing), specimens were loaded to failure at a constant displacement rate of 31 mm/min. Failure load, repair stiffness, and mode of failure were recorded. Data analysis included Shapiro-Wilk test, independent samples 2-tailed t tests, and paired t tests.

Results:

ITB-augmented repairs demonstrated a 98% stronger failure load (mean ± SD, 294.6 ± 87.9 N) than nonaugmented repairs (149.0 ± 40.4 N; P = .002) and were significantly less stiff to their native state (28.1 ± 6.7 vs 137.6 ± 98.1 N/mm; P = .023). The stiffnesses of the native tendons were not different from each other (P = .773).

Conclusion:

Gluteus medius repairs augmented with ITB grafts led to greater failure load than nonaugmented repairs and were less stiff than the native state.

Clinical Relevance:

Utilization of ITB-augmented double-row repairs when treating tears of the gluteus medius tendon can potentially reduce high failure rates.