Eradication of infection in chronic osteomyelitis requires effective dead space management after debridement. Residual bacteria in biofilm may be resistant to normal levels of systemic antibiotic penetrating bone and will contribute to recurrence of osteomyelitis. This study evaluated a new antibiotic-loaded biocomposite in the eradication of chronic infection from bone defects. We report a prospective study of 100 patients with Cierny and Mader types III and IV chronic osteomyelitis, in 105 bones. Osteomyelitis followed open fracture or ORIF of closed fractures in 71%. Nine had concomitant septic arthritis. 80% had comorbidities (Cierny-Mader Class B hosts). Ten had infected non-unions. All patients were treated by a multidisciplinary team with a single-stage protocol including; debridement, multiple sampling, culture-specific systemic antibiotics, stabilisation, dead space filling with Cerament G™ and immediate primary skin closure. Stabilisation was required in 21 cases and 5 required joint fusion as part of the initial surgery. Plastic surgical skin closure was needed in 23 cases (18 free flaps). Patients were followed up for a minimum of one year (mean 19.5 months; 12–34).Aim
Patients and Method
Trunnionosis in modular hip arthroplasty has recently been recognised to be clinically important. Gaining an understanding of how the material interface at the head-trunnion affects the tribology at the modular junctions has current clinical implications as well as an implication on future implant selection and material choice. This matched-cohort study aims to compare tribocorrosion between ceramic and cobalt-chromium trunnions and to investigate other factors that contribute to the difference in tribocorrosion if present. All hip prostheses retrieved between 1999 and 2015 at one centre were reviewed. Fifty two ceramic heads were retrieved, and these were matched to a cobalt-chromium cohort according to taper design, head size, neck length and implantation time in that order. The two cohorts were similar in male:female ratio (p=0.32) and body mass index (p=0.15) though the ceramic group was younger than the cobalt-chromium group (56.6 (+/−)13.5 years for ceramic group vs 66.3 (+/−14.4) years for cobalt-chromium group; p=0.001). There was no significant difference in the reasons for revision between the two groups (p=0.42). The femoral head trunnions were examined by two independent observers using a previously published 4-point scoring technique. The trunnions were divided into three zones: apex, middle and base. The observers were blinded to clinical and manufacturing data where possible. Ceramic head trunnions demonstrated a lower median fretting and corrosion score at the base zone (p<0.001), middle zone (p<0.001) and in the combined score (p<0.001). In a subgroup analysis by head size, ceramic heads had a lower fretting and corrosion score at 28mm head diameter (p<0.001). Within the ceramic group, taper design had a significant effect on fretting and corrosion in the apex zone (p=0.04). Taper design also had a similar effect in the cobalt-chromium group in the apex zone (p=0.03). For the ceramic trunnions, the largest effect was contributed by the difference between the 11/13 taper and the 12/14 taper. For the cobalt-chromium trunnions, the largest effect was contributed by the difference between the 5 degree 38′ 37″ taper and type 1 taper. Ceramic head trunnions showed a significantly lower fretting and corrosion score as compared to cobalt-chromium trunnions. Ceramic heads had a lower score than cobalt-chromium heads at 28mm head diameter. Taper design had an effect on fretting and corrosion within each cohort.
The role of porosity in the longevity of polymethylmethacrylate (PMMA) bone cement mantles remains unclear, although porosity reduction is probably desirable. It is not known whether pore patterns, pore distribution or pore morphology contribute to failure, since it is difficult to assess these features with traditional techniques. We used a novel microtomographic technique to quantitatively and qualitatively assess porosity in PMMA cements of differing viscosities to establish whether pore distribution can be effectively assessed and to document any differences in porosity (in both quantity, distribution and morphology). Each cement was also examined with and without the addition of vacuum, since this is thought to reduce porosity. Four PMMA bone cements of different viscosities (three of the same brand and the fourth chosen due to its popularity) were prepared and moulded according to established protocols (ASTM F451-99a), with and without the addition of vacuum. 25 samples per group (200 total) were prepared and densities for each sample calculated using Archimedes' principle. Four samples per group (total 32) were randomly selected for further analysis. These samples underwent micro-computer tomography (micro-CT) at a magnification of 20× and slice thickness of 13.67μm and reconstructed images were analysed with in-house developed software to measure pore size and volume. Results were analysed and compared with the two-sample T-test assuming significance at P<0.05. Qualitative assessment of pore character and distribution was made using three dimensional (3D) reconstruction.Introduction
Methods and materials
The histology results implied a potential acceleration in the early stage of fracture healing in the high dose (75 μg) MB group. However progression to union following this initial early phase acceleration was delayed as callus volume increased rather than union according to micro CT and histological data.
