[The direct anterior approach to the hip revision]

The objective of this paper is to describe a minimally invasive approach to revision total hip arthroplasty.

Indications for revision hip arthroplasty are septic or aseptic loosening of one or both components of a hip arthroplasty. In revisions the direct anterior approach (DAA) allows for a small incision if only the cup has to be revised or in cases of stem revision; the femoral preparation can be performed strictly endofemorally from the proximal direction. The gluteal muscles can be preserved whether the approach is limited to the original interval between the musculus tensor fasciae latae and the rectus, or has to be extended.

If preservation of the gluteal muscles is desired, the DAA and its extension are the method of choice. For endofemoral revision other than detachment of the musculus tensor fasciae latae, hyperextension and adduction of the operated leg are important. If these cannot be achieved, an alternative operative strategy or a different approach should be considered. As this approach allows for extensions proximally and distally along the femur, it competes with lateral approaches to the hip joint and femur, and does not have additional specific contraindications. The availability of specific curved, angulated, or offset instruments is mandatory.

The starting point of the incision is found two fingerbreadths lateral and two finger breadths distal to the anterior superior iliac spine. The fascia of the musculus tensor fasciae latae is incised sharply at its midpoint. The interval is prepared strictly subfacially and medially to the musculus tensor fasciae latae to expose the hip joint.

For this approach we don't have any specific recommendations. Postoperative management depends mostly on the extension of the approach and the type of reconstruction performed. If the approach can be limited to the minimally invasive direct anterior portal, reduced muscle damage should result in faster rehabilitation.

The retrospective analysis was performed on the data obtained from 48 revision operations with the minimally invasive direct anterior approach to total hip arthroplasty. The median cut-suture time was 108 min (42-282 min); patients spent a median time of 10 days (4-33 days) in the hospital from the day of the operation. The most common revision operations were cup replacement with an augmentation ring (13 out of 48), stem revision (11 out of 48), cup replacement (9 out of 48), H-TEP complete (3 out of 48), removing of ossifications (2 out of 48), cap revision (2 out of 48) and H-TEP removal with insertion of a spacer (2 out of 48). Complications attributed to the procedure were reported in 9 of the 48 cases: 1 wound-healing disorder, 1 late infection, 1 hematoma, 1 deep vein thrombosis, 1 perforation (by the spacer) and 1 ossification. Two patients were diagnosed with trochanteric pain syndrome. In one case an implant loosening was diagnosed 12 months after the revision.