MINIMAL INVASIVE HIP ARTHROPLASTY IN ROUTINE

Abstract

MIS techniques in hip arthroplasty above all have the objective to shorten the rehabilitation period by suitable preparation. A modified Watson-Jones approach through the muscle interval between the middle gluteus and the tensor muscle of fascia latae via a 6 – 8 cm anterolateral skin incision provides a good overview to the preparation. The risk of damaging the lateral femoral cutaneous muscle is relatively low when a suitable incision technique is employed. The use of special instruments decisively decreases the risk of preparation errors, extension damage of the skin nerve and misimplantation of prosthesis components. Back-positioning of the patient on the operating table has clear advantages compared to lateral positioning. When the stem is prepared the proximal femur can be brought into the surgery area by re-positioning the leg under the contralateral leg without overstretching the leg which in turn might lead to extension damage of the femoral nerve. When the implant is chosen, short stems provide minimum bone loss and the advantage of a varic access to the bone, which makes the preparation substantially easier and additionally spares the soft parts. Straight stem prostheses may also be implanted using this method, however, here the danger of an extension damage of the femoral nerve is given by the hyperextension of the leg during preparation. A further common minimal invasive approach is ventral access between the tensor muscle of fascia latae and the sartorious muscle. Here in particular with muscular patients the danger of damaging the rectus femoris by post-operative bleeding is given. The skin is incised in alignment with the lateral femoral cutaneous muscle, which is to be displayed imperatively to be spared. For stem preparation an even more disadvantageous hyperextension of the leg is required. The two-incision-technique where the straight stem is implanted by a gluteussnip – comparable with femur nailing – only provides a very bad view at the proximal femur. Here there is a greater risk of an unnoticed bone fissure when cement-free pressfit stems are used. The advantage of this technique lies in minor hyperextension of the leg for preparation.

Minimal invasive hip arthroplasty provides advantages for the patients above all in the early rehabilitation stage. However, the total concept is to be “minimal invasive” and skin incision, sparing of soft parts, choice of prosthesis and duration of surgery are to be considered.