Photodynamic therapy (PDT) requires a photosensitiser, a light source of an appropriate wavelength, and the presence of molecular oxygen. Once stimulated to its excited phase by the light, the photosensitiser reacts with oxygen to form free radicals of ‘singlet oxygen’ which is cytotoxic to microorganisms. We aim to demonstrate the effectiveness of PDT as an A PDT treatment protocol was devised using lawns of bacteria on agar plates. PDT was targeted towards the bacteria and the remaining microorganisms were quantified using a serial dilution technique. In order to assess the ability of photodynamic therapy to target biofilms on metallic implants, biofilms were cultured on polished titanium and hydroxyapatite-coated titanium discs and subjected to PDT.Aim
Method
The heat produced by drills, saws and PMMA cement in the handling of bone can cause thermal necrosis. Thermal necrosis could be a factor in the formation of a fibrous tissue membrane and impaired bony ingrowth into porous prostheses. This has been proposed to lead to non-union of osteotomies and fractures, the failure of the bone-cement interface and the failure of resurfacing arthroplasty. We compared three proprietary blades (the De Soutter, the Stryker Dual Cut and the Stryker Precision) in an in-vitro setting with porcine tibiae, using thermocouples embedded in the bone below the cutting surface to measure the increases in bone temperature. There was a significant (p=0.001) difference in the change in temperature (δT) between the blade types. The mean increase in temperature was highest for the De Soutter, 2.84°C (SD: 1.83°C, range 0.48°C to 9.30°C); mean δT was 1.81°C (SD: 1.00°C, range 0.18°C to 4.85°C) for the Precision and 1.68°C (SD: 0.95°C, range 0.24°C to 5.67°C). Performing paired tests, there was no significant difference in δT between the Precision and Dual Cut blades (p=0.340), but both these blades had significantly (p=0.003 for Precision vs De Soutter, p<0.001 for Dual Cut vs De Soutter) lower values for δT than the Dual Cut.
We present a retrospective comparative review of the radiological outcomes of Chevron and Scarf with Akin osteotomy in the treatment of hallux valgus.
The mean post-operative intermetatarsal angles (IMA) were: Chevron mean 8.050, standard deviation 2.560, standard error 0.57. Scarf with Akin mean 7.220, standard deviation 2.56, standard error 0.57. The difference in postoperative IMA between the two groups did not achieve statistical significance. The mean change in IMA for each was: Chevron mean increment 4.90 Standard deviation 2.290, standard error 0.51. Scarf with Akin mean increment 6.680, standard deviation 4.130, and standard error 0.88. The difference in alteration of IMA between the two groups did not achieve statistical significance.
These radiological outcomes were compared with alignment outcomes for ‘Star’ total ankle replacement, as published by PLR Wood. (Total Ankle Replacement JBJS April 2003 85B, pg 334)
32/35 Angle A were within the published accepted range (850–950). 23/35 Angle B were within the published accepted range (800–900). 35/35 Angle C were within the published accepted range (200–400) No statistical difference between the distribution of angle A, B and C and the means for A, B and C for the published results.
A lower angle B positions the implant on metaphyseal bone with a risk of subsidence. Comparing Angle B with a modified acceptable range (850–950) 31/35 fell in the new range.
