Rheumatology, Autoimmunity and Orthopedics

Two of best MIS hip approaches at least theoretically are the Röttinger muscles sparing Watson-Jones anterolateral approach in decubitus lateralis and the Pflüger at al MIS anterolateral approach in supine position but in our hands difficulties were present, especially during learning curve, to mobilize the femur without excessive superomedial capsule and external rotators e.g. piriformis and/or obturator internus release. External rotators release increases hip laxity and longer arthroplasty necks are usually used resulting to leg lengthening. In this new approach, only the gluteus minimus insertion tendon is temporary elevated and no branches of serious arteries e.g. of lateral circumflex artery are injured. The operating leg is not placed in extension but in 20° flexion, to avoid stress on abductors, as also in adduction and external rotation. The opposite leg is stabilized at the posterior leg support and the anterior is removed. The opposite leg in slight abduction and extension facilitates even more the femoral access. This approach may be used systematically in all primary or secondary osteoarthritis even in obese patients. In these cases, the skin incision may easily be extended without e.g. lateral cutaneous nerve of the thigh or deep femoral artery branches limitations of the anterior MIS approaches. The main restrictions are the severe posterior acetabular wall insufficiency or some high congenital dislocation cases. Gluteus minimus is strongly resutured at the end of the surgery at its normal place without consequences, the gait is immediate, hospitalization stay is normally 1-2 days and blood transfusion is very rare. Course in 725 patients operated with this new technique, in 342 of them using a short curved antirotation uncemented stem and a new generation threaded cup, is spectacular compared to the classic approaches and is more successful than our previously published less invasive and bloodless lateral MIS hip approach.