Total hip arthroplasty by direct anterior approach versus posterolateral approach. A randomized clinical trial.

A variety of surgical approaches have been proved successful for total hip
arthroplasty (THA). The approaches are posterolateral (Moore or Southern),
lateral (Hardinge or Liverpool), anterolateral in supine position
(Watson-Jones) or in lateral decubitus position (Mallory) and anterior
(Smith-Petersen). Over the past decades the posterolateral and anterolateral
approach have predominantly been used for THA. The main reason for world wide
use of these approaches was the familiarity to surgeons.
More recently the orthopaedic community has shown significant interest to
surgical approaches that lessen trauma to soft tissue and bone in order to
allow faster patient rehabilitation and reduced pain. These so-called minimally
invasive total hip arthroplasty approaches can be divided into three basic
categories: an abbreviated incision (small incision), modifications of standard
approaches with smaller incisions and less soft-tissue dissection (less
invasive), and novel approaches that reportedly do not cut muscle (minimally
invasive).
We believe the single-incision direct anterior approach is the only truly
minimally invasive approach for THA. The direct anterior approach (DAA) namely
follows intermuscular and internervous planes reaching the hip joint.
Potentially this approach leads to reduced blood loss, smaller incisions,
reduced pain, shorter hospital stay, faster recovery, more rapidly return to
daily activities and a reduced risk of dislocation. However the benefits of
different surgical approaches for THA continue to be debated. In this
randomized controlled clinical trial will be investigated whether there's a
difference in functional, clinical and radiological outcome between the direct
anterior approach and the posterolateral approach in THA.

Primary objective:
Demonstrating that direct anterior approach results in higher patient
satisfaction than posterolateral approach in total hip arthroplasty.

Secundary objective:
- Demonstrating a difference in secundary clinical and functional outcomes
between DAA and PLA in THA.
- Demonstrating a difference in radiological outcome between DAA and PLA in THA.
- Demonstrating a difference in number of complications between DAA and PLA in
THA.

Single-centre randomized controlled clinical trial, comparing DAA with PLA.
These two groups will be evaluated prospectively, using randomisation with
changing block size, stratificated for surgeon subject to allocation
concealment.
Patient and surgeon are not blinded, investigator and statistician are blinded
for the entire study.

Total hip arthroplasties (THA) will be performed by the department of
orthopedic surgery in the Isala Clinics, Zwolle (The Netherlands). 120 THA's
will be performed in total, of which 60 by posterolateral approach and 60 by
direct anterior approach. Both surgeons perform 60 cemented THA's, of which 30
posterolateral and 30 direct anterior.
THA's will be performed with the following compents:
- Stem: Link SP-II
- Cup: Link FAL
- Cup: Biolox ceramic
All patients are subjected to the same preoperative protocol, postoperative
rehabilitation and blood- and painmanagement. In every patient systemic
profylactic antibiotics (cefazolin 2 gr intravenous) and pharmacological
thromboprofylaxis (fondaparinux 0.3mg SC till 5 weeks postoperative) is given.
Instruction course in direct anterior approach is required for both surgeons.

Conform recent literature one can reasonably assume per-and postoperative
complication risk in direct anterior approach is comparable with posterolateral
approach.
There's minimal additional effort for patients, only 1 extra hospital visit (3
weeks postoperative) and some patient scores to complete.