Two major challenges in arthroplasty are obesity and antibiotic resistance. This study was performed to characterise the organisms responsible for deep infection following total hip arthroplasty and to determine if obesity affected the microbiology profile.

A retrospective analysis of the national surgical site infection register was made to obtain data regarding deep infection following 10948 primary total hip arthroplasty (THA) from 1998–2013, with a minimum of 2 year follow-up.

Of all the primary THAs performed, there were 108 deep infections (56 patients had a BMI >30 (obese) and 52 patients <30). There were no significant differences between cardio-respiratory disease, smoking and alcohol status, and diabetes between the 2 groups. Over the last 15 years, staphylococcus aureus continues to be the most frequently isolated organism. Infection with multiple organisms was found exclusively in obese patients. Furthermore, in obese patients, there was a linear increase with methicillin resistant staphylococcus aureus (MRSA) infections and streptococcus viridans.

On this basis, we recommend careful selection of antibiotic therapy in obese patients, rather than empirical therapy, which can be especially important if there is no growth in an infected THA. In addition, a preoperative discussion regarding dental prophylaxis against streptococcus viridans may be warranted.

When performing total knee replacement (TKR), surgeons must select a size of tibial component tray that most closely matches the anatomy of the proximal tibia. As implants are available in a limited range of sizes, it may be necessary to slightly under or oversize the component. There are concerns overhang could lead to pain from irritation of soft tissues, and underhang could lead to subsidence and failure.

154 TKRs at 1- or 5-year follow up were reviewed prospectively. Oxford Knee Score (OKS), WOMAC and SF-12 was recorded along with pain scores. Scaled radiographs were reviewed and grouped into perfect sizing (78 TKRs, 50.6%), underhang in isolation (48 TKRs, 31.1%), minor overhang 1–3 mm (10 TKRs, 6.49%) or major overhang >3 mm (18 TKRs, 11.7%).

There was no significant difference in the SF-12 (p=0.356), post-operative OKS (p=0.401) or WOMAC (p=0.466) score. For the OKS, there was no difference for the scores collected at 1 year (p=0.176) or at 5 years (p=0.883).

Pre-operative OKS was well matched between the groups (p=0.152). There was no significant difference in the improvement in OKS from pre-operative scores (p=0.662). There was no significant difference in either the OKS or WOMAC pain scores (p=0.237 and 0.542 respectively).

There was no significant association of medial overhang with?medial knee pain (p=1.000) or lateral overhang with lateral knee pain (p=0.569) when compared to the group of patients with a well sized tibial component.

Our results suggest that tibial component overhang or underhang has no detrimental affect on outcome or pain scores. Surgeons should continue to select the tibial component that most closely fits the rim of the proximal tibia while accepting slight overhang if necessary due to the potential longer-term complications of subsidence and premature failure with an undersized tibial tray.

Knee osteoarthritis is common, disabling and can be effectively treated by total knee arthroplasty (TKA). In North America, consideration has been given to the varying outcomes amongst racial groups. However, scant attention has been paid to the outcomes of surgery in different racial groups found in the United Kingdom (UK). We investigated the results of surgery in one of the principal ethnic minorities in the UK; that of a south Asian population.

We retrospectively analysed our prospectively collected database at the Southern General Hospital, Glasgow. We identified 39 Asian patients who had TKA. They were age and sex matched to a Caucasian group. Mean follow up was 40.3 months.

Mean pre-operative oxford knee scores were poorer than in the Caucasian group (8.5 vs. 14.7, p=0.001.) Post operative oxford knee scores were similarly poorer in the Asian group (29.9 vs. 36.1, p=0.07.) Interestingly, the change in oxford knee scores was similar in both groups.

SF-12 and WOMAC scores demonstrated poorer pre and post operative scores in the Asian group. Knee flexion was greater in the Asian group, however (107.5° vs. 106.2°, p=0.742.)

We conclude that while patients of Asian origin have poorer post operative pain and function following TKA, they have a similar gain from surgery as do a Caucasian group and therefore surgery is effective intervention in this group. An important topic for further work is to identify why Asians present later in their arthritic disease process to healthcare professionals than do their Caucasian counterparts.

Cardiovascular disease is now the leading cause of morbidity and mortality worldwide. Raised blood pressures (BP) are associated with increased cardiovascular risks such as myocardial infarction, stroke and arteriosclerosis. During surgery the haemodynamic effects of stress are closely monitored and stabilised by the anaesthetist. Although there have been many studies assessing the effects of intraoperative stress on the patient, little is known about the impact on the surgeon.

A prospective cohort study was carried out using an ambulatory blood pressure monitor to measure the BP and heart rates (HR) of three consultants and their respective trainees during hallux valgus, hip and knee arthroplasty surgery. Our principle aim was to assess the physiological effects of performing routine operations on the surgeon. We noted if there were any differences in the stress response of the lead surgeon, in comparison to when the same individual was assisting. In addition, we recorded the trainee's BP and HR when they were operating independently. The intraoperative measurements were compared with their baseline readings and their stress response, assessed using the Bruce protocol.

Many trends were noted in this pilot study. All of the surgeons had higher BP and HR readings on operating days compared to baseline. The physiological parameters normalised by one hour post-theatre list in all subjects. When the trainer was leading the operation, their BP gradually increased until implant placement, while their trainees remained stable. On the other hand, when the trainee was operating and the trainer assisting, the trainer's BP peaked at the beginning of the procedure, and slowly declined as it progressed. The trainee's BP remained elevated throughout. The highest peaks for trainees were noted during independent operating.

We conclude that all surgery is stressful, and that trainees are more likely to be killing themselves than their trainers.

Anterior knee pain following primary total knee replacement (TKR) is a common problem with average reported rates in the literature of approximately 10%. Symptoms are frequently attributed to the patellofemoral joint, and the treatment of the patella during total knee replacement is controversial.

There is no article in the literature that the authors know of that has specifically evaluated the effect of patella rim cautery on TKR outcome. This is a denervation technique that has historically been employed, with no evidence base. A prospective comparative cohort study was performed to compare the outcome scores of patients who underwent circumferential patella rim cautery, with those who did not.

Patients who had undergone a primary TKR were identified from the unit's arthroplasty database. Two cohorts, who were age and gender matched, were established. None of the patients had their patella resurfaced, but all had a patellaplasty. The Low Contact Stress TKR (Depuy International) was used in all cases.

The effect of circumferential patella rim cautery on the Oxford Knee Score (OKS) and the more anterior knee pain specific Patellar Score (PS) a minimum of 2 years post surgery was evaluated. Previous reports have suggested that a change of 5 points in the OKS represents a clinical difference. A sample size calculation based on an effect size of 5 points with 80% power and a p-value of 0.05 would require a minimum of 76 patients in each group.

There were 94 patients who had undergone patellaplasty only, and 98 patients who had supplementary circumferential patella rim cautery during their primary TKR. The mean OKS were 34.61 and 33.29 respectively (p=0.41), while the PS scores were 21.03 and 20.87 (p=0.87).

No statistically significant differences were noted between the groups for either outcome score. Patella rim cauterisation is unnecessary in primary TKR.