Purpose: Authors introduce short term results, hazards and solutions of 250 two incision MIS hip replacement performed in their institute. Aspects of one incision techniques are detailed with differences in indication .

Methods: Between April 2003 and September 2004 250 two-incision minimally invasive total hip replacements were performed in authors institute. The cup and the stem is implanted through two incisions using physiological muscle route between m. sartorius and m. tensor fasciae latae and the m.rectus femoris and the m. gluteus medius. Preparation of the stem is done through an incision made above the greater trochanter through a gluteus maximus split straight done to the piriformis fossa. No muscles and tendons are detached Neurovascular hazards, complications with solutions are introduced. Indication is determined by pathoanatomy and weight of the patient. 115 osteoarthritis, 72 aseptic necrosis, 57 dysplastic and 6 posttraumatic patients were operated.

Results: The operation performed on properly selected patients results in increased primary stability, because of preserving structures like the iliotibial tract, muscles and the iliofemoral ligament, causing minimal soft tissue damage. There was no dislocation. Radiological analysis revealed more than 3 degrees malalignment in 3,7 % for stem and in 5,1% for cup. Fluoroscopy and OP time was reduced to av. 6 secs. Average flexion was 76 degrees in the first two post op days. Post operative pain was significantly reduced. Hospital stay was 3,2 days. There was no infection, nor heterotopic ossification. In 5 cases the femur fractured and wiring was necessary through the anterior incision. 1 revision for cemented stem was necessary because of stem migration due to extreme size of femur . Conversion to lateral exposure was done in one case.

Conclusions: Two incision minimally invasive total hip replacement is technically more demanding, requiring adequate training and knowledge. Appropriate indication is inevitable. Hospital stay and rehabilitation time is reduced also resulting in economic benefit, though not compromising good result of THR.

Aims: The relationship between the structural and histological changes of articular hyaline cartilage and the stiffness of this tissue was evaluated. Methods: Artscan 1000, an articular stiffness tester was used for in vivo measurements during arthroscopy indicated on orthopaedic or trauma disorders. 100 patients were involved in the study. Measurements were performed at eight standard sites: medial and lateral femoral condyles, medial and lateral tibial condyles, medial and lateral facet of the patellofemoral joint and medial and lateral facet of the patella. Standard 10N predefined loading force was applied during the measurements. The indenter force produced by the deformed cartilage tissue is used as the indicator of cartilage stiffness. Results: Clinical measurements revealed a topographical variation of the stiffness of normal cartilage. In general, the femoral cartilage is stiffer than tibial or patellar one. The stiffest cartilage was measured at the lateral femoral condyle. Conclusions: Changes of articular cartilage structure can be indirectly observed during arthroscopy as an alteration in cartilage stiffness.