The Wagner Cone Stem for the Management of the Challenging Femur in Primary Hip Arthroplasty.

BACKGROUND: Splined conical stems offer design features that facilitate their use in the misshapen, dysplastic proximal femur. METHODS: This study assessed the survivorship of a conical prosthesis when applied to secondary coxarthrosis because of a range of pathologies. Fifty-one prostheses were implanted in 50 patients with a mean age of 50 (range, 15-80) and a median follow-up of 34 months (range, 24-73 months). Indications for the stem included developmental (36), neuromuscular (7), post-traumatic or surgical (7), and inflammatory conditions (1). Survivorship, functional outcome (WOMAC [Western Ontaria and McMaster University Osteoarthrits Index], Oxford Hip Score, and UCLA [University of California Los Angeles]), health status (short form-12 [SF-12]), satisfaction, and osseointegration were determined. RESULTS: Survivorship for aseptic loosening was 100% at 2 years and 98.04% for septic revision. Eight patients required reoperation, 4 for instability, and 1 each for infection, impingement, adverse reaction to metal debris, and pelvic insufficiency fracture. The mean WOMAC score was 85 (standard deviation [SD], 18), the mean Oxford Hip Score 84 (SD, 18), the mean physical SF-12 score was 48.3 (SD, 8.6), and the mean mental SF-12 was 53.7 (SD, 9.2), the mean satisfaction score was 91.5 (SD, 3.9), and the mean UCLA was 6 (SD, 1.6). All femoral components demonstrated osseointegration. CONCLUSION: The cone femoral prosthesis demonstrates excellent early survival and osseointegration when applied to the challenging femur. Because of these encouraging results, we recommend this prosthesis be considered for the small, abnormal femur in primary hip arthroplasty.

Acetabular liner with focal constraint to prevent dislocation after THA.

BACKGROUND: Dislocation continues to commonly cause failure after primary and revision total hip arthroplasty (THA). Fully constrained liners intended to prevent dislocation are nonetheless associated with a substantial incidence of failure by redislocation, mechanical failure, aseptic loosening, or a combination. Constrained liners with cutouts of the elevated rims can theoretically increase range of movement and therefore decrease the risk dislocation, but it is unclear if they do so in practice and whether they are associated with early wear or loosening. QUESTIONS/PURPOSES: We therefore determined (1) occurrence or recurrence of dislocation and (2) rate of complications associated with constrained implants with cutouts; and (3) assessed for early cup loosening. METHODS: We retrospectively reviewed the records of 81 patients at high risk for dislocation who had 82 constrained liners inserted for primary (n = 10) or revision (n = 72) THA between 2008 and 2010. From the records we extracted demographic and implant data and instances of recurrent dislocation, implant failure, osteolysis, loosening, or construct failure. The minimum followup was 24 months (mean, 34 months; range, 24-49 months). RESULTS: Three liners failed as a result of further dislocation (3%). Three deep infections occurred. One patient had progressive loosening at the shell-bone interface. CONCLUSIONS: Our observations suggest this liner is associated with a relatively low risk of dislocation in patients at high risk for dislocation and those with recurrent dislocation.

Intra-operative imaging technique to aid safe placement of screws in percutaneous fixation of pelvic and acetabular fractures.

Percutaneous internal fixation of pelvic fractures is becoming increasingly more popular among trauma surgeons worldwide due to reduced surgical related morbidity and facilitation of early mobilisation. Visualisation of the pelvic bony anatomy during percutaneous fixation is difficult, making the procedure technically demanding. We present a simple and easy intra-operative imaging technique that helps to confirm safe positioning of screws, particularly in the narrow anterior acetabular column, by use of radiopaque contrast medium to define the appropriately drilled track.

HIV1 protease inhibitors selectively induce inflammatory chemokine expression in primary human osteoblasts.

HIV-infected patients are at increased risk of decreased bone mineral density. Several studies have implicated antiretroviral therapy as a contributor to the decreased bone mineral density seen in treated HIV-1 patients. Whilst the exact molecular mechanisms underlying decreased bone density remain to be elucidated, inflammation has been postulated to be an important pathogenomic mechanism. In this study, we have explored primary human osteoblast gene expression in response to protease inhibitors (PIs), by oligonucleotide microarray analysis. A list of dysregulated genes, correlated with the inflammatory response, increased significantly after NFV and RTV exposure. Analysis of gene and protein expression determined a selectively increase of the pro-inflammatory cytokines monocyte chemoattractant protein (MCP)-1 and interleukin-8 (IL-8) following exposure to a pharmacological concentration of NFV and RTV. These data suggested that generation of local inflammatory cascades may contribute to the development of decreased bone mineral density in highly active antiretroviral therapy (HAART)-treated HIV patients.

Posterior intrafocal pinning for reduction of oblique, extension supracondylar humeral fractures in children: a technical note.

A closed reduction technique using a posteriorly inserted intrafocal Kirschner wire for unstable Gartland type-III supracondylar humeral fractures in children is described. This surgical technique has been used in 7 patients. None had neurovascular complications, and all achieved bone union and had good or excellent functional and cosmetic results.

Clostridium perfringens infection complicating periprosthetic fracture fixation about the hip: successful treatment with early aggressive debridement.

Periprosthetic fracture and infection are both challenges following hip arthroplasty. We report the case of an 87 year old female who underwent open reduction and internal fixation of a periprosthetic femoral fracture. Her post-operative course was complicated by infection with Clostridium perfringens. Early aggressive antibiotic treatment and surgical debridement were successful, and allowed retention of the original components.

Vertebral fractures and concomitant fractures of the sternum.

From October 1996 to August 2001, 721 patients with vertebral fractures were admitted to our unit. Ten patients suffered from vertebral fractures and concomitant sternal fractures. The clinical notes and plain film radiographs of these patients were studied. The average age of the patients was 37 (20-69) years. Nine had been involved in road traffic accidents. Three patients had fractures of the cervical spine, six of the upper thoracic spine (T1-T6) and one had a lumbar spine fracture. The extra-thoracic fracture group included two patients with neurological compromise and two patients who were neurologically intact. The entire upper thoracic fracture group suffered neurological compromise, with four patients suffering complete neurological deficit. In addition, four of these patients suffered potentially life-threatening intra-thoracic injuries. The relative severity of the neurological compromise and the attendant injuries in the upper thoracic fracture group offers compelling evidence in support of the "fourth column" theory, as expressed by Berg [Berg EE (1993), The sternal-rib complex. A possible fourth column in thoracic spine fractures. Spine 18(13):1916-1919].