Minimal Invasive Surgery in Total Hip Arthroplasty Patients; Short- and Long Term Results

• Abductor muscle strength [ Time Frame: 3 months postoperatively ] [ Designated as safety issue: No ]
  Measured by 1 repetition maximum (1 RM)
  
  

• Hip joint functionality and mobility [ Time Frame: 3 months postoperatively ] [ Designated as safety issue: No ]
  Measured by patient completed questionnaires and clinician reported scores
  
  
• activity level [ Time Frame: 6 subsequent days postoperatively ] [ Designated as safety issue: No ]
  Measured by an activity monitor
  
  

With total hip replacement surgery, the orthopaedic surgeon's aim is not only pain relief for the patient, but also restoration of hip joint biomechanics resulting in a minimal functional deficit and maximal longevity of the implant. It is not exceptional that these patients still experience mild to moderate long-term impairments postoperatively. These impairments include pain, muscle weakness of the hip abductors, contracture of the hip, gait disorders, as well as weakness of hip extensors and flexors. These problems may in turn lead to complications such as joint instability and loosening of the implant. When the lateral surgical approach is used, major concerns after total hip replacement surgery are muscle abductor weakness/atrophy, tendon defects of the gluteus minimus muscle, and unsuccessful reattachment or denervation of the anterior gluteal flap.

Minimal incision/invasive surgery (MIS) is defined as a surgical approach performed through a short skin and muscle incision to avoid injury to muscles and tendons. Following minimally invasive approach reduced muscle trauma has been found. Moreover clinical outcome improved, as the gluteus medius muscle can be spared more successfully. However, it is debated whether or not the overall results of MIS are superior, or even as good as the traditional hip replacement surgery in terms of component placing and time to revision of the prosthesis.