Osteoarthritis of the knee is a complex peripheral joint disorder with multiple risk factors. The molecular basis of osteoarthritis has been generally accepted; however, the exact pathogenesis is still not known. Management of patients with osteoarthritis involves a comprehensive history, thorough physical examination and appropriate radiological investigation. The relative slow progress in the disease allows a stepwise algorithmic approach in treatment. Non-surgical treatment involves patient education, lifestyle modification and the use of orthotic devises. These can be achieved in the community. Surgical options include joint sparing procedures such as arthroscopyando osteotomy or joint-replacing procedures. Joint-replacing procedures can be isolated to a single compartment such as patellofemoral arthroplasty or unicompartmental knee replacement or total knee arthroplasty. The key to a successful long-term outcome is optimal patient selection, preoperative counselling and good surgical technique.

Mesenchymal stem cells are sensitive to changes in feature height, order and spacing. We had previously noted that there was an inverse relationship between osteoinductive potential and feature height on 15-, 55- and 90 nm-high titania nanopillars, with 15 nm-high pillars being the most effective substrate at inducing osteogenesis of human mesenchymal stem cells. The osteoinductive effect was somewhat diminished by decreasing the feature height to 8 nm, however, which suggested that there was a cut-off point, potentially associated with a change in cell–nanofeature interactions. To investigate this further, in this study, a scanning electron microscopy/three-dimensional scanning electron microscopy approach was used to examine the interactions between mesenchymal stem cells and the 8 and 15 nm nanopillared surfaces. As expected, the cells adopted a predominantly filopodial mode of interaction with the 15 nm-high pillars. Interestingly, fine nanoscale membrane projections, which we have termed ‘nanopodia,’ were also employed by the cells on the 8 nm pillars, and it seems that this is analogous to the cells ‘clinging on with their fingertips’ to this scale of features.

ObjectivesWear debris released from bearing surfaces has been shown to provoke negative immune responses in the recipient. Excessive wear has been linked to early failure of prostheses. Analysis using coordinate measuring machines (CMMs) can provide estimates of total volumetric material loss of explanted prostheses and can help to understand device failure. The accuracy of volumetric testing has been debated, with some investigators stating that only protocols involving hundreds of thousands of measurement points are sufficient. We looked to examine this assumption and to apply the findings to the clinical arena. MethodsWe examined the effects on the calculated material loss from a ceramic femoral head when different CMM scanning parameters were used. Calculated wear volumes were compared with gold standard gravimetric tests in a blinded study. ResultsVarious scanning parameters including point pitch, maximum point to point distance, the number of scanning contours or the total number of points had no clinically relevant effect on volumetric wear calculations. Gravimetric testing showed that material loss can be calculated to provide clinically relevant degrees of accuracy. ConclusionsProsthetic surfaces can be analysed accurately and rapidly with currently available technologies. Given these results, we believe that routine analysis of explanted hip components would be a feasible and logical extension to National Joint Registries.Cite this article: Bone Joint Res 2014;3:60–8.

When taper junction damage is identified during revision of a LD MoM hip, it should be suspected that a male taper composed of a standard CoCr alloy has sustained significant changes to the taper cone geometry which are likely to be more extensive than those affecting a Ti alloy stem. Cite this article: 2017;99-B:1304-12.

ObjectivesTo review the current best surgical practice and detail a multi-disciplinary approach that could further reduce joint replacement infection.MethodsReview of relevant literature indexed in PubMed.ResultsSurgical site infection is a major complication following arthroplasty. Despite its rarity in contemporary orthopaedic practice, it remains difficult to treat and is costly in terms of both patient morbidity and long-term health care resources.ConclusionsEmphasis on education of patients and all members of the health-care team and raising awareness in how to participate in preventative efforts is imperative.

High-intensity narrow-spectrum (HINS) light is a novel violet-blue light inactivation technology which kills bacteria through a photodynamic process, and has been shown to have bactericidal activity against a wide range of species. Specimens from patients with infected hip and knee arthroplasties were collected over a one-year period (1 May 2009 to 30 April 2010). A range of these microbial isolates were tested for sensitivity to HINS-light. During testing, suspensions of the pathogens were exposed to increasing doses of HINS-light (of 123mW/cm(2) irradiance). Non-light exposed control samples were also used. The samples were then plated onto agar plates and incubated at 37°C for 24 hours before enumeration. Complete inactivation (greater than 4-log10 reduction) was achieved for all of the isolates. The typical inactivation curve showed a slow initial reaction followed by a rapid period of inactivation. The doses of HINS-light required ranged between 118 and 2214 J/cm(2). Gram-positive bacteria were generally found to be more susceptible than Gram-negative. As HINS-light uses visible wavelengths, it can be safely used in the presence of patients and staff. This unique feature could lead to its possible use in the prevention of infection during surgery and post-operative dressing changes. Cite this article: Bone Joint J 2015;97-B:283-8.

Allogenic blood is a finite resource, with associated risks. Previous studies show intraoperative cell salvage (ICS) can reduce allogenic transfusion rates in orthopaedic surgery. However, there are concerns regarding efficacy and cost-effectiveness of ICS. This study was carried out to review ICS use in revision hip arthroplasty.All patients who underwent ICS and re-infusion between 2008 and 2010 in the Southern General Hospital (SGH) were audited. The fall in haemoglobin (Hb), volume of blood re-infused and postoperative allogenic transfusion rates were recorded. This group was compared to a similar SGH cohort who underwent surgery by the same surgeons between 2006 and 2008, and a pre-2005 control group where no ICS was used.The proportion of patients receiving a postoperative allogenic transfusion fell by 55% in the 2008–2010 ICS cohort compared with the control, and by 40% compared with the previous ICS group. In both instances, there was a statistically significant (p < 0.001) reduction in mean units transfused per patient; in the 2008–2010 ICS cohort, a mean of 0.8 units was used per patient, while 1.4 were used in the 2006–2008 cohort. 3.5 units were used in the control group. There was no statistically significant difference in age or preoperative Hb between the groups, or in length of hospital stay.In this study, ICS has been shown to be effective in reducing rates and volume of postoperative allogenic transfusion in patients undergoing revision hip surgery at the SGH. However, further work is needed to establish the effect of changing anaesthetic technique on postoperative allogenic transfusion rates.

Periprosthetic joint infection (PJI) remains an extremely challenging complication. We have focused on this issue more over the last decade than previously, but there are still many unanswered questions. We now have a workable definition that everyone should align to, but we need to continue to focus on identifying the organisms involved. Surgical strategies are evolving and care is becoming more patient-centred. There are some good studies under way. There are, however, still numerous problems to resolve, and the challenge of PJI remains a major one for the orthopaedic community. This annotation provides some up-to-date thoughts about where we are, and the way forward. There is still scope for plenty of research in this area. Cite this article: Bone Joint J 2022;104-B(11):1193–1195.