Computer-assisted Minimally Invasive Total Hip Surgery: a randomized controlled trial into the effectiveness compared to traditional Total Hip Arthroplasty.

Moderate to severe osteoarthrosis is the most common indication for Total Hip
Arthroplasty (THA). THA has proven to be one of the most successful orthopedic
interventions. Minimally Invasive Total Hip Surgery (MIS) and Computer Assisted
Surgery (CAS) were introduced several years ago. However, the literature lacks
well-designed studies that provide objective evidence of the superiority of
computer-assisted MIS compared to a traditional technique.

The purpose of this study is to compare the effectiveness of computer-assisted
MIS with a traditional technique for THA. Primary research question is if
computer-assisted MIS leads to a better recovery during the early postoperative
period (3 months), and at 6 months postoperatively to a recovery at least as
good as THA with a traditional incision technique.
Additionally, does it lead to a decrease in length of hospital stay, fewer
perioperative complications and a better positioning of the prosthesis, and are
there indications for potential cost savings.

A cluster randomized controlled trial will be executed. Patients (N=132) will
be stratified by means of the Charnley classification. They will be randomly
allocated to have MIS using the minimally invasive single-incision anterior
approach or the traditional procedure using a standard posterolateral incision.
Measurements take place preoperatively, perioperatively, and 6 weeks and 3 and
6 months postoperatively.

Patients in the MIS group will have surgery using the minimally invasive
single-incision anterior approach. Using special retractors, reamers and
insertion handles it is possible to perform this procedure in a minimally
invasive way, limiting the skin incision from about 15 cm. to about 8 cm. To
optimize placement of the acetabular and femoral components of the total hip
prosthesis, computer navigation will be used. The minimally invasive technique
will be compared to the traditional posterolateral approach. The anesthetic,
analgesic and postoperative physiotherapy protocols will be standardized.

There are no additional risks with respect to participation in this study other
than the normal risks if a regular procedure would have been executed.

The extent of the burden for participating patients is limited. They have to
fill in a questionnaire 4 times and execute a gait analysis 4 times
(approximately 30 min in total each time). These measurements will take place
in combination with the regular pre- end postoperative visits to the outpatient
clinic. Only for the thrid measurment patients have to come back to the
outpatient clinic seperately.