The Potential of Fasting and Caloric Restriction to Mitigate Radiation Damage-A Systematic Review.

Detrimental health effects from ionizing radiation to living organisms is one of the key concerns identified and addressed by Radiation Protection institutions, nationally and internationally on Earth and for human spaceflight. Thus, new methods for mitigating the adverse effects of ionizing radiation are urgently needed for terrestrial health and deep space exploration. Caloric restriction and (intermittent-) fasting have been reported to elicit a variety of immediate and long-term physiological effects. The rapidly growing body of evidence of research studies investigating the effects of caloric restriction and dietary fasting points toward a multitude of benefits affecting numerous physiological systems. Therefore, a systematic review was performed to evaluate the evidence of caloric restriction and dietary fasting on the physiological response to ionizing radiation in humans and animals. All experimental studies of humans, animals, and eukaryotic cell lines available in PubMed, Cochrane library, and specialized databases were searched comparing irradiation post-caloric restriction or fasting to a non-nutritionally restricted control group on a broad range of outcomes from molecular to clinical responses. The initial search yielded 2,653 records. The final analysis included 11 studies. Most studies investigated survival rate or cancer occurrence in animals. Included studies did not reveal any benefit from pre exposure caloric restriction, except when performed with post radiation caloric restriction. However, the effects of pre-exposure fasting suggest increased resilience to ionizing radiation.

The theoretical mortality risk of an asymptomatic patient with a negative SARS-CoV-2 test developing COVID-19 following elective orthopaedic surgery.

AIMS: The risk to patients and healthcare workers of resuming elective orthopaedic surgery following the peak of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has been difficult to quantify. This has prompted governing bodies to adopt a cautious approach that may be impractical and financially unsustainable. The lack of evidence has made it impossible for surgeons to give patients an informed perspective of the consequences of elective surgery in the presence of SARS-CoV-2. This study aims to determine, for the UK population, the probability of a patient being admitted with an undetected SARS-CoV-2 infection and their resulting risk of death; taking into consideration the current disease prevalence, reverse transcription-polymerase chain reaction (RT-PCR) testing, and preassessment pathway. METHODS: The probability of SARS-CoV-2 infection with a false negative test was calculated using a lower-end RT-PCR sensitivity of 71%, specificity of 95%, and the UK disease prevalence of 0.24% reported in May 2020. Subsequently, a case fatality rate of 20.5% was applied as a worst-case scenario. RESULTS: The probability of SARS-CoV-2 infection with a false negative preoperative test was 0.07% (around 1 in 1,400). The risk of a patient with an undetected infection being admitted for surgery and subsequently dying from the coronavirus disease 2019 (COVID-19) is estimated at approximately 1 in 7,000. However, if an estimate of the current global infection fatality rate (1.04%) is applied, the risk of death would be around 1 in 140,000, at most. This calculation does not take into account the risk of nosocomial infection. Conversely, it does not factor in that patients will also be clinically assessed and asked to self-isolate prior to surgery. CONCLUSION: Our estimation suggests that the risk of patients being inadvertently admitted with an undetected SARS-CoV-2 infection for elective orthopaedic surgery is relatively low. Accordingly, the risk of death following elective orthopaedic surgery is low, even when applying the worst-case fatality rate. Cite this article: Bone Joint J 2020;102-B(9):1256-1260.

Why Do Patellofemoral Stabilization Procedures Fail? Keys to Success.

In recent years, surgical interventions for patellofemoral joint instability have gained popularity, possibly revitalized by the recent advances in our understanding of patellofemoral joint instability and the introduction of a number of new surgical procedures. This rise in surgical intervention has brought about various complications. In this review article, we present the complications that are associated with 5 main surgical procedures to stabilize the patella-medial patellofemoral ligament reconstruction, tibial tubercle osteotomy, trochleoplasty, lateral release/lateral retinacular lengthening, and derotation osteotomies. The key to success and potential problems with these surgical techniques are highlighted in the form of "expert takeaways."

Retrospective cohort study of the South Tyneside Exercise Referral Scheme 2009-14: predictors of dropout and barriers to adherence.

Background: Exercise Referral Schemes (ERS) are a prevalent method of increasing physical activity levels. However, they suffer from participant dropout and research predicting dropout or barriers to adherence are limited. This study aimed to focus upon the effect of referral characteristics on dropout, dropout predictors and whether self-reported barriers to exercise predict dropout. Methods: ERS data from 2009 to 2014 were retrieved for analysis. Chi-squared and t-tests were used to investigate differences between referral characteristics, and logistic regression used to investigate dropout predictors. Results: Of 6894 participants, 37.8% (n = 2608) dropped out within 6 weeks and 50.03% (n = 3449) by the final 12th week. More males adhered (P < 0.001) with dropouts being significantly younger (P < 0.001). Dropout predictors were smoking (OR = 1.58, 95% CI: 1.29-1.93) or being a Tier 3 referral (OR = 1.47, 95% CI: 1.25-1.73). Increasing age (OR = 0.98, 95% CI: 0.98-0.99), drinking alcohol (OR = 0.82, 95% CI: 0.71-0.95), secondary care referrals (OR = 0.68, 95% CI: 0.52-0.90), having a lack of motivation (OR = 0.81, 95% CI: 0.69-0.95) or a lack of childcare (OR = 0.69, 95% CI: 0.50-0.95) decreased the likelihood of dropout. Conclusion: ERS dropout continues to be problematic. Smoking and having moderate-high comorbidities predicted dropout. Increasing age and patient-reported barriers of a lack of time or childcare decreased dropout risk. The reasons for dropout require further investigation.

An evaluation of the effectiveness of medial patellofemoral ligament reconstruction using an anatomical tunnel site.

PURPOSE: Medial patellofemoral ligament (MPFL) reconstruction for recurrent patellar instability has gained popularity, and anatomical and biomechanical studies have recently altered our operative techniques. The aim of this study was to report the clinical outcome of this new anatomical MPFL reconstructive technique and investigate whether correlating factors could be identified. METHODS: Between 2009 and 2012, a total of 31 consecutive patients underwent MPFL reconstruction using an autologous gracilis graft and anatomical tunnel placement. Pre- and post-operative data were collected as a part of routine clinical practice. The preoperative assessment included a rotational profile CT scan of the lower extremity according to the Lyon protocol with TT-TG distance measurement. Outcomes were evaluated with the Kujala and Norwich patella instability (NPI) scores preoperatively and at follow-up (1.5-5.1 years). RESULTS: A significant improvement in both the Kujala (p < 0.001) and NPI (p = 0.012) scores was recorded. A medium and large negative correlations were found between TT-TG distance and Kujala score improvement (ρ = -0.48, p = 0.020) and NPI score improvement (ρ = -0.83, p = 0.042), respectively. Multiple regression analysis identified TT-TG distance, Beighton score and BMI as factors explaining the variance of Kujala score improvement. CONCLUSION: Anatomical MPFL reconstruction with the gracilis autograft for patellar instability resulted in good outcome. This underlines the importance of anatomical tunnel placement in MPFL reconstruction. With a precise preoperative work-up, factors can be identified that may guide selecting the optimal operative strategy and improve counselling of the patient. LEVEL OF EVIDENCE: Case series, Level IV.

Gait analysis of fixed bearing and mobile bearing total knee prostheses during walking: do mobile bearings offer functional advantages?

BACKGROUND: Limited previous findings have detailed biomechanical advantages following implantation with mobile bearing (MB) prostheses after total knee replacement (TKR) surgery during walking. The aim of this study was to compare three dimensional spatiotemporal, kinematic, and kinetic parameters during walking to examine whether MBs offer functional advantages over fixed bearing (FB) designs. METHODS: Sixteen patients undergoing primary unilateral TKR surgery were randomised to receive either a FB (n=8) or MB (n=8) total knee prosthesis. Eight age and gender matched controls underwent the same protocol on one occasion. A 12 camera Vicon system integrated with four force plates was used. Patients were tested pre-surgery and nine months post-surgery. RESULTS: No significant differences between FB and MB groups were found at any time point in the spatiotemporal parameters. The MB group was found to have a significantly reduced frontal plane knee range of motion (ROM) at pre-surgery than the FB group (FB=14.92±4.02°; MB=8.87±4.82°), with the difference not observed post-surgery. No further significant kinematic or kinetic differences were observed between FB and MB groups. Fixed bearing and MB groups both displayed spatiotemporal, kinematic, and kinetic differences when compared to controls. Fixed bearing and MB groups differed from controls in six and five parameters at nine months post-surgery, respectively. CONCLUSIONS: No functional advantages were found in knees implanted with MB prostheses during walking, with both groups indicative of similar differences when compared to normal knee biomechanics following prosthesis implantation. LEVEL OF EVIDENCE: Level II.

Post-operative gait analysis in total hip replacement patients-a review of current literature and meta-analysis.

Gait analysis has been used to measure gait adaptations following total hip replacement (THR) for many years. In this time, advances have been made in implant technology and surgical procedure. However, gait adaptations persist after surgery. This review of seven published studies, where gait characteristics were compared between post-operative THR patients and healthy controls, had the objective of investigating current practice in gait analysis of this patient population and to determine if there is a consensus on post-operative gait changes associated with THR. Levels of methodological quality and study design were found to be variable. Meta-analyses were performed on all gait variables reported by at least three studies to determine overall Cohen's d effect sizes and 95% confidence intervals. Reductions in walking velocity (d=-0.79; CI=-1.54, -0.04), stride length (d=-1.06; CI=-1.62, -0.49) and sagittal hip range of motion (d=-1.58; CI=-2.12, -1.04) were observed. Increases in peak hip flexion (d=0.52; CI=-0.01, 1.09) and extension (d=0.54; CI=-0.10, 1.09) moments were found, although these were likely to be of less clinical significance. Reduced peak hip abduction was also observed (d=-0.58; CI=-1.09, -0.06). Future developments in THR technology and surgical methods should therefore aim to reduce the differences between patients and controls in terms of walking velocity, stride length, hip range of motion and hip abduction moments.