Periprosthetic fractures of the femur in primary total hip arthroplasty: a New Zealand Joint Registry analysis.

BACKGROUND: Periprosthetic femoral fractures around total hip arthroplasty (THA) are increasing annually, and are a major cause for revision surgery in the New Zealand Joint Registry (NZJR). The aim of this study was to determine the timing and risk factors for periprosthetic femoral fractures in THA requiring revision surgery in the NZJR. METHODS: All patients with a primary THA who sustained a periprosthetic femoral fracture requiring revision THA recorded in the NZJR were reviewed to determine age, gender, body mass index, American Society of Anesthesiologists (ASA) rating and femoral stem fixation (cemented or uncemented). Revision rates were calculated per 100 component years (cy), and risk factors determined in the first 90 days, and beyond. RESULTS: Between 1999 and 2017, there were 713 revision THA for periprosthetic femoral fractures. Early revision THA was significantly associated with ASA score and body mass index ≥40. There was no gender difference (P = 0.274). The revision rate in uncemented femoral stems (1.12/100 cy) was significantly higher (p < 0.001) than cemented stems (0.16/100 cy). After 90 days, the revision rate was significantly higher with increasing age (P < 0.001), males (P < 0.001) and higher ASA score (P < 0.001). The difference between cemented (0.07/100 cy) and uncemented (0.05/100 cy) stems did not reach statistical significance (P = 0.108). CONCLUSION: The rate of revision THA for periprosthetic femoral fracture is higher in uncemented femoral stems in the first 90 days, and is significantly associated with ASA score and morbid obesity. After 90 days, the rate is lower for uncemented femoral stems, but did not reach statistical significance.

Pectoralis Major Rupture in an Active Female.

Pectoralis major rupture was historically a rare occurrence, but the incidence is increasing. Most cases occur from indirect trauma in active men aged 20 to 40 years, especially during bench press. Pectoralis major rupture has never been reported in the literature in a woman in this age group. We report the first case of pectoralis major rupture in a young, active woman who underwent successful surgical fixation.

Terahertz scattering by subwavelength cylindrical arrays.

We demonstrate the use of a full-wave electromagnetic field simulator to verify terahertz (THz) transmission-mode spectroscopic measurements of periodic arrays containing subwavelength cylindrical scatterers. Many existing THz scattering studies utilize analytical solutions, which were developed for a single scatterer. For multiple scatterers, a scaling factor equal to the number of scatterers is applied, accounting for interference between far-field radiative contributions from those scatterers but not their near-field mutual coupling. Consequently, analytical solutions do not accurately verify measurements. Conversely, results from the full-wave electromagnetic field simulator elucidate our measurements well, and provide an important insight into how the scattering behavior of cylindrical scatterers is influenced by test conditions.

Subungual Bowen's disease treated by topical aminolevulinic acid-photodynamic therapy.

A 66-year-old man presented with an 18-month history of progressive nail dystrophy involving his left index finger. A diagnostic biopsy specimen confirmed the clinical suggestion of subungual Bowen's disease (carcinoma in situ). Various treatment options were considered, and the decision was made to treat with photodynamic therapy using topical 5-aminolevulunic acid administered as two treatments 4 weeks apart. The patient was reviewed 3 months after treatment and then regularly at 6-month intervals. Thirty months after treatment there remained no clinical evidence of recurrence of the condition with preservation of a normal nail unit. Although the successful treatment of cutaneous Bowen's disease with photodynamic therapy is well documented, this is the first report of the successful treatment of subungual Bowen's disease using topical aminolevulunic acid-photodynamic therapy.

Fluorescence microspectroscopy technique for the study of intracellular protoporphyrin IX dynamics.

We describe a technique designed to monitor the fluorescence dynamics of photosensitizers used in photodynamic therapy (PDT) at micrometer-scale locations within individual formalin-fixed cells. The accumulation of protoporphyrin IX (PpIX) within keratinocytes and fibroblasts. following incubation with 5-aminolaevulinic acid (ALA), is shown to be dependent upon both incubation time and cell proliferation status. Also, the process of photobleaching within these cells is demonstrated via the depletion in PpIX fluorescence emission during exposure to 532 nm light. All spectra show a progressive reduction of the 634 nm PpIX peak, following a bi-exponential decay that is consistent with a singlet oxygen mediated process. The rate of photobleaching, when plotted as a function of light dose, increases with reduced incident laser power. The generation of the hydroxyaldehyde-chlorin photoproduct (photoprotoporphyrin), as monitored by the increase in fluorescence emission centered on 672 nm, is also greatest when the lowest laser power is applied. When light is delivered in two fractions, PpIX fluorescence recovers during the dark period and there is an increase in bleaching rate at the onset of the second exposure. These results are qualitatively consistent with measurements performed in vivo, which demonstrate that the photodynamic dose is dependent upon fluence rate and oxygen status.