The management of severe acetabular bone defects in revision hip arthroplasty using modular porous metal components.

We investigated the early results of modular porous metal components used in 23 acetabular reconstructions associated with major bone loss. The series included seven men and 15 women with a mean age of 67 years (38 to 81), who had undergone a mean of two previous revisions (1 to 7). Based on Paprosky's classification, there were 17 type 3A and six type 3B defects. Pelvic discontinuity was noted in one case. Augments were used in 21 hips to support the shell and an acetabular component-cage construct was implanted in one case. At a mean follow-up of 41 months (24 to 62), 22 components remained well fixed. Two patients required rerevision of the liners for prosthetic joint instability. Clinically, the mean Harris Hip Score improved from 43.0 pre-operatively (14 to 86) to 75.7 post-operatively (53 to 100). The mean pre-operative Merle d'Aubigné score was 8.2 (3 to 15) and improved to a mean of 13.7 (11 to 18) post-operatively. These short-term results suggest that modular porous metal components are a viable option in the reconstruction of Paprosky type 3 acetabular defects. More data are needed to determine whether the system yields greater long-term success than more traditional methods, such as reconstruction cages and structural allografts.

Spatially well-defined binary brushes of poly(ethylene glycol)s for micropatterning of active proteins on anti-fouling surfaces.

We report a novel method for micropatterning of active proteins on anti-fouling surfaces via spatially well-defined and dense binary poly(ethylene glycol)s (PEGs) brushes with controllable protein-docking sites. Binary brushes of poly(poly(ethylene glycol) methacrylate-co-poly(ethylene glycol)methyl ether methacrylate), or P(PEGMA-co-PEGMEMA), and poly(poly(ethylene glycol)methyl ether methacrylate), or P(PEGMEMA), were prepared via consecutive surface-initiated atom transfer radical polymerizations (SI-ATRPs) from a resist-micropatterned Si(100) wafer surface. The terminal hydroxyl groups on the side chains of PEGMA units in the P(PEGMA-co-PEGMEMA) microdomains were activated directly by 1,1'-carbonyldiimidazole (CDI) for the covalent coupling of human immunoglobulin (IgG) (as a model active protein). The resulting IgG-coupled PEG microdomains interact only and specifically with target anti-IgG, while the other PEG microregions effectively prevent specific and non-specific protein fouling. When extended to other active biomolecules, microarrays for specific and non-specific analyte interactions with a high signal-to-noise ratio could be readily tailored.

Plantar dislocation of lateral tarsometatarsal joint: a case of subtle Lisfranc injury.

INTRODUCTION: We present a rare case of plantar dislocation of the cuboid, fourth and fifth metatarsal joints. Fracture-dislocation in the midfoot region may be subtle and difficult to recognise at the emergency department. CLINICAL PICTURE: A 16-year-old girl presented with lateral foot pain and swelling following a fall from a height of 3 m. Initial radiograph revealed a third metatarsal shaft fracture; however, additional views reviewed a plantar direction of fourth and fifth metatarsal dislocation from the cuboid. TREATMENT: Open reduction and internal fixation with Kirschner wires followed by immobilisation in plaster was performed. OUTCOME: She made an uneventful recovery and the wires had since been removed. CONCLUSION: This case was unusual in that there was lateral tarsometatarsal disruption with neither diastasis between the first and second metatarsals nor injury to either the first or second tarsometatarsal joints. The plantar direction of dislocation was also unusual as these injuries are usually dorsal.