Summary. Cognitive testing scores do not correlate with physical braking performance. Psychological questioning shows patients are more dependent on driving than a control group. Introduction. Returning to driving after surgery is a multifaceted issue. There are the medical aspects to consider- whether the patient is medically fit to drive. The term ‘medically fit to drive’ can encompass a range of issues which fall to doctors to solve, including the psychological and mental wellbeing. Groups whose governance involves patients or driving do not issue sound advice for patients or doctors to follow. Investigation of aspects affecting a driver's ability to control their vehicle in a safe manner could go towards providing an evidence base for guidance to be issued in the future. Methods. A custom force assessment rig was used to gather peak force and reaction time measurements from a group of patients waiting for, or having undergone lower limb surgery. A bespoke questionnaire that investigated patient's attitudes towards returning to driving; their behaviours and concerns was issued. Other mobility questions were also issued to these patients, including the lower extremity functional scale (LEFS). The final tests (Stroop task, tower of Hanoi, and the opposite worlds test [OWT]) were aimed at assessing a patient's neurological function, in an attempt to investigate the effect of post-operative cognitive dysfunction (POCD) on driving ability. These data were compared against a control cohort. Results. No significant differences were observed in the physical results between cohorts. However, significant differences between the control cohort and patient cohort were observed in a number of tests. The tower of Hanoi was the only significantly different neurological test (p=0.027). The Stroop task and OWT were not significantly different (p=0.103, p=0.131 respectively). There were significant differences in many of the psychological and mobility questions posed (reliance on driving [p<0.001], keenness to return [p=0.014], anxiety about being unable to drive [p=0.019], depression at being unable to drive [p=0.011], worries that driving would cause them pain [p<0.001], and confidence in using public transport [p=0.002]). Activity rankings also had a significant difference, with driving becoming a higher priority in the patient group (p=0.002). There were no significant differences between cohorts in physical testing, but LEFS was significantly different (p<0.001). There was no significant correlation between physical testing and neurological function, so we cannot prove nor disprove that neurological deficits affect physical function. Psychological variables and physical function did not correlate, but LEFS was correlated to a number of psychological variables. Conclusions. Due to the insignificance of correlations between neurological function tests and physical function, further work is recommended to conclusively determine whether there is a link or not. Different and/or additional neurological test batteries should be also considered, for example the CANTAB. Future studies should stratify cohorts based on surgical indication. Extension of the psychological research could identify the most popular goals or activities for those returning from surgery, potentially creating targets for the rehabilitation process

Sex hormones play important roles in the regulation of the proliferation, maturation and death of chondrocytes in the epiphyseal growth plate. We have investigated the effects of male castration on the cell kinetics of chondrocytes as defined by the numbers of proliferating and dying cells. The growth plates of normal rabbits and animals castrated at eight weeks of age were obtained at 10, 15, 20 and 25 weeks of age.

Our study suggested that castration led to an increase in apoptosis and a decrease in the proliferation of chondrocytes in the growth plate. In addition, the number of chondrocytes in the castrated rabbits was less than that of normal animals of the same age.