Three-dimensional planning-guided total hip arthroplasty through a minimally invasive direct anterior approach. Clinical outcomes at five years' follow-up.

PURPOSE: The direct anterior approach is an attractive option for total hip arthroplasty (THA) in order to achieve a quicker rehabilitation. However, this surgical technique presents a longer learning curve and a higher complications rate compared with the standard approach. We investigated whether three-dimensional (3D) planning anticipated the surgical difficulties and helped to achieve a low complications rate with respect to intra-operative complications, dislocation risk and lower limb discrepancy (LLD).

METHODS: One hundred and fifty-four consecutive patients underwent a primary cementless THA using a direct anterior approach. A 3D planning was performed in order to anticipate the difficulties that may be encountered regarding femur perforation or fracture, dislocation and LLD. All patients were assessed at a mean five years' follow-up.

RESULTS: No false route and no fracture occurred at the time of surgery. All the surgical difficulties were anticipated. A motorised reaming procedure of the femur was required in six patients because of a very dense bone or a narrow femur. A retroverted neck was used in 7 % of patients because of a torsional abnormality and enabled an increase in stability. The real implant sizes were the same as the ones planned in 97 % for the cup, 96 % for the stem and 100 % for the neck. At five years' follow-up, no dislocation occurred, no patient complained about LLD and excellent clinical outcomes were achieved.

CONCLUSIONS: This study demonstrates that 3D pre-operative planning-guided THA through a minimally invasive direct anterior approach is a safe and accurate procedure.

LEVEL OF EVIDENCE: Level IV.