The minimally invasive total hip replacement has been developed over the last years.

The advantages of minimally invasive approaches concern reduced blood loss and pain, shorter operative time, reduced length of stay, facilitated rehabilitation and increased patient satisfaction. Potential disadvantages are the need for additional training and patient education, the insufficient clinical data and the risk of compromising the final result by giving more importance to the length of incision than to the damage of the deeper tissue.

In the majority of cases, the minimally invasive techniques utilize standard prosthesis and resection of pathological tissue, including part of normal bone such as the femoral neck.

LINK MIT-H permits combining a minimally invasive approach with the insertion of a T.O.P. acetabular cup and a CFP femoral prosthesis, preserving the femoral neck. The conservation of this anatomic part facilitates a shallow entry of the prosthesis in the femoral canal, preserving the bone stock and thereby allowing a more precise reconstruction of the hip geometry. The technique appears to give good results, associating the advantages of minimally invasive surgery with the preservation of the femoral neck.

The good relation between the abductor lever arm and the adductor lever arm guarantees an elevated functional restoration, allowing a favorable and durable result in time.

The LINK MIT-H technique may be utilized with a direct lateral or through a post-lateral approach. We prefer a lateral approach, usually utilizing general instruments such as hooks and Hohmann retractors where the width of instruments is adapted to the length of incision.

A corkscrew may be useful to take out the femoral head, cutting it in the narrow part of the neck. Stein-mann pins, placed at the cranial acetabular rim as self-retaining retractors, associated with two Hohmann retractors below, allow good vision and facilitate reaming the socket. The attachment of fibre optics on the retractors is useful to have more light inside. Straight or cranked shaft instruments are very well suited in reaming and in aligning the T.O.P. acetabular cup.

The minimally invasive technique gives the best results when damaging tissues as little as possible by using a less invasive prosthesis that is easily implanted in small spaces and only replaces the pathologic bone, thereby saving the bone stock best as possible in restoring the hip geometry.

Introduction A wide range of stress-shielding phenomena following THA have been described in the past 20 years. Bone densitometry (DXA) stars as a golden standard in evaluating bone stock and bone density redistribution after total hip replacement.

In this study, DXA scan was employed to evaluate and compare the behaviour of different femoral components including a recently developed stemless implant which features complete stress transfer over the proximal femur.

Methodology A total of 120 patients, operated with six different femoral implants, were included in the present study. Five of these stems are widely commercially available (ABG, CFP, IPS, Mayo, Zweymueller) and present different patterns of stress distribution. The sixth is a custom made implant and features a pronounced lateral flare and complete femoral neck preservation. Rationale of this design is to obtain full load transfer on the proximal femur.

Average interval between the operation and the DXA exam was 3 years, each group included 20 patients. Bone mineral density was measured by DXA in the seven Gruen femoral regions (ROI), using the software metal removal (Hologic QDR 4500 W, MA-USA).

Results Differences in bone density were found in each group as well as between different groups. Significant differences (p< 0.001) were found between the stemless implant and the other five groups in zone I, IV and VII.

CFP, IPS and ABG groups showed decreased bone density in ROI I, while Mayo, IPS, ABG and Zweym-ueller were osteopenic in ROI VII. An increased bone density in ROI IV was found in Zweymueller, Mayo, ABG and IPS groups.

Conclusion Our data suggest that a conservative stemless implant with complete proximal load transfer, produces a homogeneous and more physiologic redistribution of bone density, allowing maintenance of proximal periprosthetic bone stock.