The Gibson and Moore postero-lateral approach is one of the most often used in hip replacement. The advantage of this approach is an easy execution but it’s criticized because of its invasivity to muscletendinous tissues especially on extrarotators muscles and because of predisposition to posterior dislocation.

Since June 2003 we executed total hip replacements using a modified postero-lateral approach which allows to preserve the piriformis and quadratus femoris muscles and to detach just the conjoint tendon (gemelli and obturator internus). Articular capsule is preserved and it will be anatomically sutured at the end of the procedure as well as the conjoint tendon with two transossesous sutures. Piriformis and quadratus femoris muscles result untouched by this approach.

We have executed 500 surgeries with this modified approach.

We have used different stems (straight, anatomical, modular and short) and press fit cetabular cup with polyethylene or ceramic insert and we have always used 36 mm femoral heads when allowed by the cup dimensions. We have used any size both of stems and cups without limitation due to the surgical approach. The mean age is 61.8 y.o., 324 females and 176 males. Obese patients, hip dysplasia Crowe 3 and 4 and post traumatic arthrosis are exclusion factors for the execution of this approach. If possible we have maintained the capsulo-tendinous less invasivity. The BMI is not an excluding factor because it’s just the gluteus region that is an important factor to decide if to execute or not a less invasive approach.

Analyzing our 500 cases we didn’t have any case of malpositioning of the stem in varus or valgus (more than 5°) and considering acetabular cup we had the tendency to position it in valgus position (not more than 40°) in the first 20 cases.

No leg discrepancies more than 1 cm were observed.

Intra-operative blood loss have been reduced of about 30 % and 50% in the post-operative. All the patients were able to active hip mobilization within the first day after surgery with a mean range of motion of 0–70°. The patients were mobilized the first day after surgery and 80% of them were able to assisted walk within second day after surgery. The mean time of stay in hospital was 6.8 days.

After 4 weeks 98% of the patients were able to walk without crutches.

One case of deep infection were evaluated and then solved with surgical debridement; no wound dehiscence. We had 1 case of anterior hip dislocation in dysplastic arthrosis due to a technical mistake. In 1 case we had femoral nerve palsy, then solved, probably because of anterior retractor malpositioning. We had 5 cases of piriformis muscle contracture without sciatic nerve palsy, then solved. We think that for total hip replacement this conservative postero-lateral approach, thanks to capsuletendinous modification we have adopted, could be considered an anatomical approach, which doesn’t present more dislocation risks compared to other approaches to the hip also thanks to the introduction of 36 mm femoral head that gives more stability and proprioceptiveness. Besides this approach gives the possibility of a shorter rehabilitation as seen above and it could be consider optimal for total hip replacement.

Von langenbach first described the posterior approach for total hip arthroplasty in 1874. In recent years advances in operative techniques and instrumentation have allowed surgeon to perform total hip arthroplasty through incision much smaller. The primary goal of any joint replacement is to create a biomechanically arthroplasty with excellent prosthesis position and durable interfaces.

Many american authors propose a definition of minimally invasive hip replacement when the skin incision is between 7–10 cm.

For us, to be mini-invasive means saving non only the skin but saving capsule, muscle and tendons too.

We used a mini-posterolateral approach with a mean length of 7 cm. After incision of the gluteus maximus fascia and fascia lata, the gluteus maximus muscle is blunty split. The short external rotator tendons are located; we proceed to saving the piriformis and quadratus femoris tendons. The gemelli and obturator internus tendons are detached with electrocautery. A capsulotomy is performed. The capsule and obturator tendon are tagged with heavy bone-suture for reattachment. The difficulties of the operation can be reduced if instruments developed for the technique are used.

50 cases of minimal incision posterolateral total hip arthroplasties are performed. More rapid rehabilitation and more prompt return to activities of daily living are also some advantage.

Longer follow-up is required to determine the long-term outcome but, our results encouraged to performed a mini-approach for total hip arthroplasty in patients selection.