Load Management After Gluteal Tendon Repair: A Controlled Laboratory Study.

Tendon lesions of the gluteus medius muscle require surgical repair if conservative treatment fails. Postoperatively, the success of the therapy is influenced by the loading conditions during follow-up treatment. Excessive loading of the hip joint during walking after surgery - and consequently, potential overload of the repaired gluteal tendon - could jeopardize the success of the therapy. In this controlled laboratory study, six subjects performed an instrumented 3D gait analysis using optoelectronic motion capture under three different loading conditions: full weight-bearing, partial weight-bearing, and full unloading with crutches. Gait data were used in silico in an inverse dynamics multi-body simulation to calculate tendon loading. Peak loads occurred on the gluteal tendons and the hip joint during the stance phase. The force on the gluteus medius tendon during full weight-bearing amounted to Fme = 12.0 ( ± 1.5) N/kg BW, while the force on the gluteus minimus tendon was Fmi = 5.0 ( ± 1.6) N/kg BW. Partial weight-bearing reduced these loads by ≈ 68%, whereas full unloading led to a ≈ 88% reduction compared to full weight-bearing. In the hip joint, the average maximum load during full weight-bearing reached FH = 39.8 ( ± 6.7) N/kg BW. To prevent muscle atrophy after gluteal tendon repair, the highest possible load should be applied without compromising suture integrity. Full unloading should be implemented if the tendon and/or bone integrity is compromised and suture stability is reduced. However, if stability is sufficient, partial weight-bearing is recommended.