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Refereed/Peer-reviewed Background: The objective is to determine whether body mass index is associated with patient-reported expectations and well-being before primary total hip or total knee arthroplasty, and patient-reported outcomes 6 months after surgery. Methods: Data were obtained from the Australian Orthopaedic Association National Joint Replacement Registry. Outcome measures included pre-operative expectations for post-operative mobility, joint pain and health, pre- and post-operative EQ-5D-5L, EQ-VAS, Oxford Hip/Knee Scores and joint pain scales, and post-operative perceived change and perceived satisfaction. Associations with BMI were assessed using chi-square tests, analysis of variance and Linear Mixed Models equations. Results: Data were available for 12 816 primary THA patients and 20 253 primary TKA patients. Pre-operatively, patients in higher BMI categories were significantly more likely to expect ongoing problems with mobility, more joint pain and poorer health following surgery (P

Background Patient-reported outcome measures (PROMs) are commonly used to evaluate surgical outcome in patients undergoing joint replacement surgery, however routine collection from the target population is often incomplete. Representative samples are required to allow inference from the sample to the population. Although higher capture rates are desired, the extent to which this improves the representativeness of the sample is not known. We aimed to measure the representativeness of data collected using an electronic PROMs capture system with or without telephone call follow up, and any differences in PROMS reporting between electronic and telephone call follow up. Methods Data from a pilot PROMs program within a large national joint replacement registry were examined. Telephone call follow up was used for people that failed to respond electronically. Data were collected pre-operatively and at 6 months post-operatively. Responding groups (either electronic only or electronic plus telephone call follow up) were compared to non-responders based on patient characteristics (joint replaced, bilaterality, age, sex, American Society of Anesthesiologist (ASA) score and Body Mass Index (BMI)) using chi squared test or ANOVA, and PROMs for the two responder groups were compared using generalised linear models adjusted for age and sex. The analysis was restricted to those undergoing primary elective hip, knee or shoulder replacement for osteoarthritis. Results Pre-operatively, 73.2% of patients responded electronically and telephone follow-up of non-responders increased this to 91.4%. Pre-operatively, patients responding electronically, compared to all others, were on average younger, more likely to be female, and healthier (lower ASA score). Similar differences were found when telephone follow up was included in the responding group. There were little (if any) differences in the post-operative comparisons, where electronic responders were on average one year younger and were more likely to have a lower ASA score compared to those not responding electronically, but there was no significant difference in sex or BMI. PROMs were similar between those reporting electronically and those reporting by telephone. Conclusion Patients undergoing total joint replacement who provide direct electronic PROMs data are younger, healthier and more likely to be female than non-responders, but these differences are small, particularly for post-operative data collection. The addition of telephone call follow up to electronic contact does not provide a more representative sample. Electronic-only follow up of patients undergoing joint replacement provides a satisfactory representation of the population invited to participate.

The standard Exeter stem has a length of 150 mm with offsets 37.5 to 56 mm. Shorter stems of lengths 95, 115 and 125 mm with offsets 35.5 mm or less are available for patients with smaller femurs. Concern has been raised regarding the behavior of the smaller implants. This paper analyzed data from the Australian Orthopaedic Association National Joint Replacement Registry comparing survivorship of stems of offset 35.5 mm or less with the standard stems of 37.5 mm offset or greater. At 7 years, there was no significant difference in the cumulative percent revision rate in the short stems (3.4%, 95% CI 2.4-4.8%) compared with the standard length stems (3.5%, 95% CI 3.3-3.8%) despite its use in a greater proportion of potentially more difficult developmental dysplasia of the hip cases.

The nutrient requirements and metabolic pathways used by the developing embryo transition from predominantly pyruvate during early cleavage stages to glucose at the blastocyst; however, the complexities involved in the regulation of metabolism at different developmental stages are not clear. The aims of this study were to examine the role of the malate-aspartate shuttle (MAS) in nutrient metabolism pathways in the developing mouse blastocyst and the consequences of impaired metabolism on embryo viability and fetal and placental growth. Eight-cell-stage mouse embryos were cultured in the presence of the MAS inhibitor amino-oxyacetate, with or without pyruvate as an energy substrate in the media. When the MAS was inhibited, the rate of glycolysis and lactate production was significantly elevated and glucose uptake reduced, relative to control cultured embryos in the presence of pyruvate. Despite these changes in embryo metabolism, this did not influence development to the blastocyst stage, but it did reduce the number of inner cell mass and trophectoderm cells. When these embryos were transferred to psuedopregnant females, inhibition of the MAS significantly reduced the proportion of embryos that implanted and developed into fetuses on Day 18 of pregnancy. Finally, fetal growth was reduced while placental weight was maintained, leading to a decreased fetal:placental weight ratio relative to control embryos. These results suggest that impaired metabolism of glucose in the blastocyst via the MAS alters the ability of the embryos to implant and form a pregnancy and leads to reduced fetal weight, likely via altered placental development and function.