Patellofemoral MRI Alterations Following Single Bundle ACL Reconstruction with Hamstring Autografts Are Associated with Quadriceps Femoris Atrophy

High incidence of patellofemoral pain and patellofemoral joint osteoarthritis was found following anterior cruciate ligament(ACL)reconstruction.The unstability of patellofemoral joint might be an important contribution factor.This study was designed to define the relationship between the unstability of patellofemoral joint and quadriceps femoris atrophy.Twenty patients underwent MRI scan before ACL reconstruction and every two weeks after surgery,until 12 weeks.The merchant’s patellar congruence angle,lateral inclination angle,and quadriceps femoris muscle cross-sectional area were measured and the relationship between the changes of angles and the ratio of quadriceps femoris atrophy was studied by multiple regression analysis.Significant quadriceps femoris atrophy was observed after ACL reconstruction during the follow-up period of 12 weeks.The merchant’s patellar congruence angle and lateral inclination angle significantly changed after surgery.The alterations of the merchant’s patellar congruence angle were significantly correlated with the atrophy ratio of vastus medialis(coefficient=-5.76)and vastus lateralis(coefficient=8.35)during the follow-up period of 12 weeks.The alterations of lateral inclination angle were significantly correlated with the atrophy ratio of vastus medialis(coefficient=20.62),vastus lateralis(coefficient=-11.38)and rectus femoris(coefficient=-0.469)during the follow-up period 12 weeks.To sum up,ACL reconstruction can alleviate the dysfunction of patellofemoral joint to a certain extent.But,the unbalanced atrophy of quadriceps femoris once again destroyed the stability of patellofemoral joint following the operation,which might be one cause of patellofemoral joint pain and early onset of osteoarthritis after ACL reconstruction.So,rehabilitation training that focuses on quadriceps femoris especially the vastus medialis shortly following operation is suggested.

Acute exercise in ozone-polluted air induces apoptosis in rat quadriceps femoris muscle cells via mitochondrial pathway

Ozone(O_(3))pollution can decrease sport performance and induce respiratory toxicity,but relatively few studies have investigated its effects on skeletal muscles.We randomly assigned rats to the following groups based on a 2×4 two-factor factorial design:Air+0,Air+10,Air+15,and Air+20,O_(3)+0,O_(3)+10,O_(3)+15,and O_(3)+20.The rats in the+0 groups rested,whereas those in the+10,+15,and+20 groups ran on a treadmill(in clean air for Air groups and in air polluted with 0.14 parts per million[ppm]O_(3)for O_(3)groups)at speeds of+10,+15,and+20 m/min,respectively,for 1 h.Thereafter,key enzyme activities involving the tricarboxylic acid cycle,oxidative phosphorylation,adenosine triphosphate(ATP)content,histopathological changes,oxidative stress,inflammation factors,and apoptosis were assessed in the rat quadriceps femoris samples.Ozone reduced key enzyme activities and ATP contents in the quadriceps femoris regardless of whether the rats exercised.Pathological changes,inflammatory factors,oxidative stress,and mitochondria-dependent apoptosis were only evident under conditions of exercise combined with ozone and increasingly worsened as exercise intensity increased.These findings suggested that acute exercise under ozone exposure could induce damage to the quadriceps femoris,which would negatively affect sport performance.Ozone-induced disrupted energy metabolism might be an early event that becomes more critical as exercise intensity increases.Therefore,care should be taken when exercising in polluted air,even when ozone pollution is mild.

Sonographic muscle mass assessment in patients after cardiac surgery

BACKGROUND Patients undergoing cardiac surgery particularly those with comorbidities and frailty,experience frequently higher rates of post-operative morbidity,mortality and prolonged hospital length of stay.Muscle mass wasting seems to play important role in prolonged mechanical ventilation(MV)and consequently in intensive care unit(ICU)and hospital stay.AIM To investigate the clinical value of skeletal muscle mass assessed by ultrasound early after cardiac surgery in terms of duration of MV and ICU length of stay.METHODS In this observational study,we enrolled consecutively all patients,following their admission in the Cardiac Surgery ICU within 24 h of cardiac surgery.Bedside ultrasound scans,for the assessment of quadriceps muscle thickness,were performed at baseline and every 48 h for seven days or until ICU discharge.Muscle strength was also evaluated in parallel,using the Medical Research Council(MRC)scale.RESULTS Of the total 221 patients enrolled,ultrasound scans and muscle strength assessment were finally performed in 165 patients(patients excluded if ICU stay<24 h).The muscle thickness of rectus femoris(RF),was slightly decreased by 2.2%[(95%confidence interval(CI):-0.21 to 0.15),n=9;P=0.729]and the combined muscle thickness of the vastus intermedius(VI)and RF decreased by 3.5%[(95%CI:-0.4 to 0.22),n=9;P=0.530].Patients whose combined VI and RF muscle thickness was below the recorded median values(2.5 cm)on day 1(n=80),stayed longer in the ICU(47±74 h vs 28±45 h,P=0.02)and remained mechanically ventilated more(17±9 h vs 14±9 h,P=0.05).Moreover,patients with MRC score≤48 on day 3(n=7),required prolonged MV support compared to patients with MRC score≥49(n=33),(44±14 h vs 19±9 h,P=0.006)and had a longer duration of extracorporeal circulation was(159±91 min vs 112±71 min,P=0.025).CONCLUSION Skeletal quadriceps muscle thickness assessed by ultrasound shows a trend to a decrease in patients after cardiac surgery post-ICU admission and is associated with prolonged duration of MV and ICU length of stay.