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AimsAs the population ages, there is projected to be an increase in the level of demand for total knee arthroplasty (TKA) in octogenarians. We aimed to explore whether those aged ≥ 80 years achieved similar improvements in physical function to younger patients while also comparing the rates of length of stay (LOS), discharge to rehabilitation, postoperative complications, and mortality following TKA in older and younger patients.Patients and MethodsPatients from one institution who underwent primary elective TKA between 1 January 2006 and 31 December 2014 were dichotomized into those ≥ 80 years old (n = 359) and those < 80 years old (n = 2479) for comparison. Multivariable regression was used to compare the physical status component of the 12-Item Short-Form Health Survey (SF-12), LOS, discharge to rehabilitation, complications, and mortality between the two groups.ResultsBoth age groups demonstrated a clinically meaningful improvement in their self-reported physical health relative to their baseline with no clinically relevant difference noted between them. Being ≥ 80 years old was associated with a 0.58-day increase in LOS and older patients were more likely to be discharged to rehabilitation (odds ratio (OR) 3.06, p < 0.001). Medical complications and mortality were higher in elderly patients (OR 1.92 for complications, p < 0.001; hazard ratio 3.40 for death, p < 0.001). There was no statistically significant association between age group and experiencing a postoperative surgical or wound-related complication.ConclusionThose aged over 80 years achieved a statistically significant lower median SF-12 physical score than the younger group, after adjusting for the preoperative score, but this difference of 4.46 was not considered to be clinically meaningful. However, clinicians should be aware that the elderly are at a higher risk of experiencing longer hospital stays, postoperative medical complications, and mortality.Cite this article: Bone Joint J2018;100-B:1463–70.

ABSTRACTThe management of prosthetic joint infections remains a clinical challenge, particularly infections due to methicillin-resistant staphylococci. Previously, this infection was considered a contraindication to debridement and retention strategies. This retrospective cohort study examined the treatment and outcomes of patients with arthroplasty infection by methicillin-resistant staphylococci managed by debridement and retention in conjunction with rifampin-fusidic acid combination therapy. Over an 11-year period, there were 43 patients with infection by methicillin-resistant staphylococci managed with debridement and retention. This consisted of close-interval repeated arthrotomies with pulsatile lavage. Rifampin was combined with fusidic acid for the majority of patients (88%). Patients were monitored for a median of 33.5 months (interquartile range, 20 to 54 months). Overall, 9 patients experienced treatment failure, with 12- and 24-month estimates of infection-free survival of 86% (95% confidence interval [CI], 71 to 93%) and 77% (95% CI, 60 to 87%), respectively. The following factors were associated with treatment failure: methicillin-resistant Staphylococcus aureus(MRSA) arthroplasty infection, a single surgical debridement or ≥4 debridements, and the receipt of less than 90 days of antibiotic therapy. Patients with infection by methicillin-resistant coagulase-negative staphylococci (MR-CNS) were less likely to fail treatment. The overall treatment success rate reported in this study is comparable to those of other treatment modalities for prosthetic joint infections by methicillin-resistant staphylococci. Therefore, the debridement and retention of the prosthesis and rifampin-based antibiotic therapy are a valid treatment option for carefully selected patients.

The role of computer-assisted surgery in maintaining the level of the joint in primary knee joint replacement (TKR) has not been well defined. We undertook a blinded randomised controlled trial comparing joint-line maintenance, functional outcomes, and quality-of-life outcomes between patients undergoing computer-assisted and conventional TKR. A total of 115 patients were randomised (computer-assisted, n = 55; conventional, n = 60).Two years post-operatively no significant correlation was found between computer-assisted and conventional surgery in terms of maintaining the joint line. Those TKRs where the joint line was depressed post-operatively improved the least in terms of functional scores. No difference was detected in terms of quality-of-life outcomes. Change in joint line was found to be related to change in alignment. Change in alignment significantly affects change in joint line and functional scores.

We carried out a prospective, continuous study on 529 patients who underwent primary total knee replacement between January 2006 and December 2007 at a major teaching hospital. The aim was to investigate weight change and the functional and clinical outcome in non-obese and obese groups at 12 months post-operatively. The patients were grouped according to their pre-operative body mass index (BMI) as follows: non-obese (BMI < 30 kg/m2), obese (BMI 330 to 39 kg/m2) and morbidly obese (BMI > 40 kg/m2). The clinical outcome data were available for all patients and functional outcome data for 521 (98.5%). Overall, 318 (60.1%) of the patients were obese or morbidly obese.At 12 months, a clinically significant weight loss of = 5% had occurred in 40 (12.6%) of the obese patients, but 107 (21%) gained weight. The change in the International Knee Society score was less in obese and morbidly obese compared with non-obese patients (p = 0.016). Adverse events occurred in 30 (14.2%) of the non-obese, 59 (22.6%) of the obese and 20 (35.1%) of the morbidly obese patients (p = 0.001).

This paper describes an investigation into the teaching of a programming language by methods of computer-assisted instruction (CAI). The subjects were first-year university students who were divided into groups to enable comparisons to be made first between CAI lessons and conventional lectures and secondly between on-line examples sessions and the usual demonstration classes. The selection into groups were determined mainly on the student's performance in a programming aptitude test but other factors such as previous programming experience, availability and objections to the methods of instruction were considered. All students were given a post-test in an effort to determine how much they had assimilated during the week. An analysis of covariance on these two scores gives estimates of the effects of placement in a particular group. Conclusions are drawn and suggestions made as to how future investigations should be made in the light of this experiment.

CAI course authors have been faced with the distinct problem of having to learn an instructional coding language before they can get their courses into the computer. A system has been devised so that an author may easily write his course in English on course planning forms and then a preprocessor will generate the coding which will be input for the machine assembler.

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