*Jan Kochanowski University in Kielce, Orthopaedic and Traumatology Clinic Kielce, Poland

†Alab Clinic, Zawodzie, Warsaw, Poland

‡Hip Arthroscopy Mexico, Av. Frida Kahlo, Monterrey, Mexico

§Orthopaedic and Trauma Department, Medical University of Lodz, Poland

∥Medical University of Gdańsk, Gdańsk, Poland

All the procedures that involved human participants were performed in accordance with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. The study was approved by the Ethics Committee of the Medical University of Łódź (RNN/94/12/KB 21.02.2012).

Informed consent was obtained from all individual participants included in the study.

The authors declare no conflict of interest.

Address correspondence and reprint requests to Maciej Gnatowski, MD, Wielicka 43/31, Warsaw 02-657, Poland. E-mail: [email protected].