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Background and purpose There have been few reports documenting the wear and oxidation performance of the polyethylene bearing surface of HGPI and HGPII THA devices.We evaluated retrieved HGPI and HGPII acetabular liners that had been in situ for more than 10 years and determined whether there was a relationship between clinical and radiographic factors, surface damage, wear, and oxidation.Materials and methods 129 HGPI and II acetabular liners with implantation times of > 10 years were retrieved at 4 institutions between 1997 and 2010. The liners were made from a single resin and were gamma radiation-sterilized in air. Surface damage, linear wear, and oxidation index (OI) were assessed. Differences in clinical and radiographic factors, surface damage, linear wear, and OI for the 2 designs were statistically evaluated separately and together.Results Articular surface damage and backside damage was similar in the 2 designs. The linear penetration rate was 0.14 (SD 0.07) mm/year for the HGPI liners and 0.12 (SD 0.08) mm/year for the HGPII liners. For both cohorts, the rim had a higher OI than the articular surface. 74% of the liners had subsurface cracking and 24% had a complete fracture through the acetabular rim.Interpretation Despite modification of the HGP locking mechanism in the HGPII design, dissociation of the liner from the acetabular shell can still occur if fracture of the rim of the liner develops due to oxidative degradation.

Purpose The variables causing symptomatic accessory navicular are largely unknown and may inform management of symptomatic patients. The purpose of this study was to examine patient specific factors associated with the development of accessory navicular symptoms. Methods A total of 71 patients with clinical and radiographic evidence of accessory navicular syndrome were evaluated. Patient gender, race, date of birth, date of earliest foot complaint and laterality were recorded. Treatment was defined as conservative versus surgical. Skeletal maturity was assessed based on calcaneal ossification, accessory navicular subtype and the presence of pes planus based on talo-first metatarsal angle were assessed. Results Female patients comprised 72% of the subjects and trended towards symptoms at younger ages than male patients (p = 0.06), while no significant difference in presentation age was appreciated between male and female patients. Skeletal maturity was significantly associated with earlier complaints and age at presentation but was not associated with increased need for surgical management. Patients with pes planus were significantly more likely to undergo operative management. Accessory navicular subtype was significantly correlated with skeletal maturity. Conclusion Female patients were more likely to report symptoms and present with symptomatic accessory navicular. The stage of skeletal maturity is not a predictor of future surgical management but patients with a higher first-metatarsal angle were more likely to require surgery. The correlation between accessory navicular subtype and skeletal maturity suggests that Type II ossicles are likely to develop into Type III over time. Radiographic evaluation of the accessory navicular may lend prognostic data on the necessity of future surgical intervention. Level of Evidence IV, Case Series