“Like other craftsmen, we have often two ways at least of doing the same job, the success of which is dependent upon the character and the integrity of the man. “Approaches” are for us both physical and psychological: in the case of the hip joint it seems clear that there is more than one good method and that, for the sake of those we train, we should keep an open mind.”. Norman A. Capener, 1950. Orientation relative to the abductor musculature and ease of access to the pathology in question should provide the compelling basis for selection of operative approaches to the hip, rather than being based solely on surgeon habit. Approaches to primary total hip arthroplasty remain the surgeon's choice; posterior approaches provide challenges to cup orientation and anterior approaches offer more difficult access to the proximal femur. Imperatives for a decubitus position posterior approach include pelvic dissociation with need for posterior column plating, removal of retained posterior hardware, and sciatic neurolysis after prior injury. Conversely, indications for a supine anterolateral approach include an isolated acetabular revision with a well-fixed femoral stem and the need for retroperitoneal removal of an
One cementless cup which had porous outer surface with Apatite-Wollastonite glass ceramic (AWGC) coating, was revised 13 years after primary THA because of massive osteolysis expanded to medial iliac wall along the screws. While many retrieved studies of hydroxyapatite-coated cup have been reported, there has been no report on the retrieved cup with AWGC coating. The purpose of this study was to describe this rare case in detail, confirm the bone ingrowth to the porous cup, and discuss on the effectiveness of porous surface with AWGC coating. Case. The patient was a 64 old woman and complained of chronic mild pain around her left groin region. X-ray examination revealed that osteolysis had been expanding around the screws and extended proximally. The revision surgery was performed for the massive osteolysis through Hardinge antero-lateral approach. The retrieved implants included a cementless cup made of titanium alloy (QPOC cup, Japan Medical Materirals Inc.(JMM) Osaka, Japan), the outer surface of which was plasma-sprayed with titanium for porous formation and coated with AWGC in the deep layer. It was found that the polyethylene liner was destructed partially in the supero-lateral portion, but the cup was well fixed to the bone. The bone-attached area was found to be dispersed over the porous surface of the hemispherical cup. Histological examination revealed that matured bony tissue intruded into the porous surface of the cup, and contacted to bone directly, which was also demonstrated in the back-scattered electron image. It was also demonstrated that there were residual silicon (Si) rich regions on the porous surface by the SEM-EDX analysis, which indicated that constituents of AWGC still remained on the surface. On the other hand, the results of elementary analyses in the Si rich regions varied among the sections, which probably indicated that the extent of degradation and absorption of AWGC varied among the sections. AWGC was one of the bioactive ceramics and reported to have an ability to bond to bone earlier than hydroxyapatite (HA). In the present case, though massive osteolysis occurred with aggressive wear, it did not expand on the porous surface, and rather progressed along the smooth surface of the screws. Considering that there are many clinical studies reporting poor clinical results of HA-coated smooth cups, bioactive ceramic coating may function well and bring superior clinical results when combined with porous coated substrate. In our study, though the cause of massive polyethylene wear and
