The effect of poly sterilization on wear, osteolysis and survivorship of a press-fit cup at 10-year followup.

Background: During the mid-1990s when our institution was using a press-fit porous-coated cup without supplemental initial fixation for primary THA, the manufacturer transitioned from gamma irradiation to gas plasma for the terminal sterilization of their polyethylene liners.

Questions/purposes: At minimum 10-year followup, we asked whether the fixation achieved by solely relying on a press-fit would be durable and how different liner sterilization methods affected radiographic wear, osteolysis, and survivorship.

Patients And Methods: We retrospectively reviewed 373 patients who underwent 398 primary THAs with a press-fit porous-coated cup between March 1995 and December 1996.

Osteolysis propensity among bilateral total hip arthroplasty patients.

Because some patients with high wear rates demonstrate extensive osteolysis whereas other patients with similarly high wear rates show little or no evidence of osteolysis, we hypothesized that both polyethylene wear and a patient-specific propensity mediate the development of osteolysis. We evaluated wear and osteolysis using computed tomography and radiographs among 46 patients who had undergone bilateral total hip arthroplasties (THAs). A radiographic patient-specific propensity for osteolysis associated with each THA was quantified by dividing the amount of osteolysis by the volumetric wear.

Five Duraloc locking ring failures.

We report on 5 cases that underwent revision for locking ring failure in the Duraloc product line (DePuy, Warsaw, Ind). All liner retrievals showed signs of posterior neck/liner impingement and superior edge loading or significant wear. In these cases, we believe superior head migration and neck/liner impingement due to cup anteversion contributed to these locking ring failures.

A comparison of a second- and a third-generation modular cup design: is new improved?

The highly cross-linked polyethylene liners currently used with modular uncemented cups have substantially decreased wear and osteolysis at early follow-up. However, retroacetabular osteolysis has still been reported in some cases with DePuy Orthopaedic's (Warsaw, IN) second-generation Duraloc acetabular shell. DePuy's third-generation Pinnacle cup incorporates a different shell-liner locking mechanism.

Can the volume of pelvic osteolysis be calculated without using computed tomography?

Unlabelled: The most common method to diagnose and monitor osteolysis is the standard anteroposterior radiograph. Unfortunately, plain radiographs underestimate the incidence and extent of osteolysis. CT scans are more sensitive and accurate but also more expensive and subject patients to more radiation.

Results of the anatomic medullary locking total hip arthroplasty at a minimum of twenty years. A concise follow-up of previous reports.

Between October 1982 and December 1984, the senior author performed 223 total hip arthroplasties in 215 patients with use of the anatomic medullary locking hip stem and TriSpike cup. We now report on 119 of these hips at a mean of 22.0 years (range, 20.

The skeletal effects of glucocorticoid excess override those of orchidectomy in mice.

Hypogonadism has been implicated as a contributing factor in glucocorticoid-induced osteoporosis, but evidence for this is limited. Hypogonadism and glucocorticoid excess both cause bone loss, but the cellular mechanisms responsible are distinct. Loss of gonadal steroids causes an increase in bone remodeling by up-regulating osteoblastogenesis and osteoclastogenesis.

Glucocorticoids act directly on osteoblasts and osteocytes to induce their apoptosis and reduce bone formation and strength.

Whether the negative impact of excess glucocorticoids on the skeleton is due to direct effects on bone cells, indirect effects on extraskeletal tissues, or both is unknown. To determine the contribution of direct effects of glucocorticoids on osteoblastic/osteocytic cells in vivo, we blocked glucocorticoid action on these cells via transgenic expression of 11beta-hydroxysteroid dehydrogenase type 2, an enzyme that inactivates glucocorticoids. Osteoblast/osteocyte-specific expression was achieved by insertion of the 11beta-hydroxysteroid dehydrogenase type 2 cDNA downstream from the osteoblast-specific osteocalcin promoter.

Promotion of osteoclast survival and antagonism of bisphosphonate-induced osteoclast apoptosis by glucocorticoids.

Glucocorticoids depress bone formation by inhibiting osteoblastogenesis and increasing osteoblast apoptosis. However, the role of bone resorption in the initial rapid phase of bone loss characteristic of glucocorticoid-induced osteoporosis is unexplained, and the reason for the efficacy of bisphosphonates in this condition remains unknown. We report that in murine osteoclast cultures, glucocorticoids prolonged the baseline survival of osteoclasts and antagonized bisphosphonate-induced caspase activation and apoptosis by a glucocorticoid receptor-mediated action.