RESTORATION DLS: A NEW CONCEPT IN DISTAL LOCKING HIP REVISION

Abstract

Hip revision failures are partly due to the poor quality of femoral bone stock. Several work showed that bone reconstruction without grafts is possible around a non cemented, stable stem. It is enhanced by a transfemoral approach.

We designed the Restoration TM DLS stem (anatomical, S curved, HA coating and distal locking to ensure a primary stability).

Preoperative planning is necessary. The operative technique is based on a double postero-lateral femoral flaps approach. An innovating and modular instrumentation was developed. It rests on a femoral clamp that solidarises the femur and the trial stem, and allows a precise adjustment of the length and the stem anteversion. A targeting device allows a precise distal locking of the final implant. Osteosynthesis of the flaps is carried out by cerclages in order to bring the bone around the prosthesis.

Forty-seven revisions cases were followed up. No major peroperative incident has occurred. We report one case of locking error. Compared to the planning, the instrumentation was considered to be precise in 94% for the adjustment of the leg length and of the ante-version. The bone adaptation around the implant was generally correct. In 21 cases, it was necessary to carry out metaphysal re-calibration or osteotomies for correction of a femoral deviation. The synthesis of the flaps is stable in 92%. For follow up greater than 3 months, the consolidation of the osteotomies is effective in 90%.

This study made it possible to validate a surgical procedure by transfemoral approach that makes safe implant and cement removal. It also allowed us to validate an innovating, precise yet flexible instrumentation that allows, after preoperative planning, the anatomical reconstruction of the femur around the stem. A perfect proximal adaptation of the femur to the implant is necessary to the good tolerance of the distal locking.