Influence of the use of frontal surgical access on biomechanical gait image and functional outcome of the lower limb in patients after hip arthroplasty

The purpose of the study will be to assess the impact of frontal, intra-muscular operating access on the biomechanical gait image and the functional outcome of the lower limb in patients after hip replacement. The alternative solution for lateral access that is gaining an increasing number of followers is minimally invasive access from the frontal accession. Minimally invasive access is defined as the absence of muscle and / or bone damage combined with short cutaneous cut. Minimally invasive does not mean a short scar, but as little damage to soft tissues, especially muscles and their attachment. Muscle protection accelerates movement improvement, allowing for a faster discharge from the surgical ward The advantage of front access is the maintenance of undamaged muscles and their attachment to the pelvis and femur. This access uses the space between the iliotibial band and the gluteus medius. This allows them to return to their correct tension immediately after the operation. No damage to muscles and their attachment increases the dynamic, muscular stabilization of the operated hip. The qualification for research will be based on the simple randomisation of research group. Allocation of patients to the research group will be decided upon the coin-tossing. Heads – patient is participating in the research, tails – patient does not take part in the research. After the surgery, patients were randomly divided into two groups. Patients for particular groups will be always qualified by the same person - first researcher. The first group is the patients who will have a frontal, intramuscular operation access during surgery, while the second group will have lateral surgical access. The first test session will take place one week before the procedure. After 6 and 12 weeks, the examination will be re-performed. All procedures will be carried out by first researcher. Surgery will be performed by orthopaedic surgeon Research will include: 1. Analysis of the medical documentation of the patient. 2. Measurement of kinematic and kinetic parameters of gait based on three-dimensional motion analysis using the BTS Smart system in conjunction with the torque platform. The analysis will include: - angular changes in the three planes of knee, hip, and ankle joints, - changes in the length of selected muscles, - changes in ground-reaction forces - time-spatial parameters: number of steps per minute, time of single and double support, length and duration of full cycle, and speed of walk. 3. Registration of biopotentialities arising in the gluteus muscles (bilateral for maximus and medium gluteus muscles). Duration of the surgical procedure: 2 hours Overall duration of the assessments – 2 hours: 1. 1 hour for clinical examination, 2. 1 hour for gait and EMG test,