ABSTRACT
BACKGROUND:The maximum muscle strength is typically used for evaluating the recovery of muscle function after anterior cruciate ligament reconstruction.Recent studies have suggested that neuromuscular function should also be considered,such as rate of force development,which measures the slope of the force time curve at different time intervals under conditions of isometric muscle contraction. OBJECTIVE:To elaborate on the current research status and shortcomings of muscle isometric rate of force development in patients undergoing anterior cruciate ligament reconstruction surgery,and analyze the degree of defects in quadriceps femoris and hamstring isometric rate of force development at different times after surgery;to analyze the effect of isometric rate of force development on postoperative functional performance,thereby providing important information for optimizing postoperative rehabilitation following anterior cruciate ligament reconstruction,reducing secondary injury to patients,and reducing the incidence of knee osteoarthritis. METHODS:Literature retrieval of CNKI,VIP,WanFang and PubMed was performed using"anterior cruciate ligament,rate of force development"as Chinese search terms and"anterior cruciate ligament,rate of force development,rate of torque development"as English search terms.Finally,69 articles were included according to inclusion and exclusion criteria. RESULTS AND CONCLUSION:Most studies have found defects in bilateral muscle isometric rate of force development in patients undergoing anterior cruciate ligament reconstruction within 6 months.Early isometric rate of force development of the bilateral hamstring muscles(i.e.the slope of the force time curve at any time interval during muscle contraction of 100 ms)showed significant improvement after 6 months.However,long-term defects in early isometric rate of force development of the bilateral quadriceps indicate long-term damage to the neuromuscular function of the quadriceps after surgery.There is limited research on late isometric rate of force development(the slope of the force time curve at any time interval after 100 ms of muscle contraction),and conclusions cannot be drawn.Regarding landing exercises(jumping to the ground,lateral cutting,etc.)and daily activities(walking,running),early isometric rate of force development of the quadriceps is more correlated with isometric peak torque.Abnormal biomechanical changes during exercise are considered an important risk factor for secondary injury and traumatic knee osteoarthritis in patients.Actively improving early isometric rate of force development of the quadriceps may reduce the incidence of secondary injury and traumatic knee osteoarthritis.Currently,there is limited evidence to suggest that whole-body vibration training can improve early isometric rate of force development of the quadriceps femoris in patients undergoing anterior cruciate ligament reconstruction.It is recommended to use neuromuscular electrical stimulation to intervene in the quadriceps and hamstring in the early postoperative stage and implement explosive force and high resistance training in the late postoperative stage,which may improve the isometric rate of force development in patients.Generating sufficient muscle strength in a short period of time is necessary to effectively protect the anterior cruciate ligament,while the relationship between isometric rate of force development in the hamstring muscle and functional performance is still unclear,which may provide information on preventing secondary injury in patients.It is recommended to use the isometric rate of force development as one of the evaluation indicators for guiding rehabilitation and restoring movement.In addition to focusing on improving symmetry and differences from normal individuals,the hamstring to quadriceps strength ratio should also be considered.An appropriate range of ratios can ensure the balance of muscles during rapid muscle exertion,which may reduce the occurrence of secondary injuries.However,the normal range of ratios is not yet clear.Future research should consider the effects of graft type and knee flexion angle on isometric rate of force development,in order to identify neuromuscular dysfunction in patients as much as possible and help them recover better.
ABSTRACT
<p><b>OBJECTIVE</b>To study the clinical and genetic characteristics of twins and siblings affected with Wilson's disease (WD).</p><p><b>METHODS</b>Clinical data and blood samples were collected from the subjects after informed consent was obtained. Genomic DNA was extracted and potential mutations in the exons in ATP7B gene were detected with PCR-DNA sequencing. Short tandem repeat (STR) genotyping was performed to determine the zygosity of the twins.</p><p><b>RESULTS</b>The 5 pairs of twins have all met the diagnostic criteria for WD. STR genotyping has confirmed that 4 pairs were monozygotic twins. 3 pairs of twins had an onset with liver symptoms, the other 2 had an onset with brain symptoms. ATP7B gene mutations were detected in 4 pairs of twins, which have all located in exons 8 and 13. A heterozygous p.R778W mutation in exon 8 and homozygous p.P992L mutation in exon 13 were detected in all patients from one family, whose parents have carried a heterozygous p.R778W mutation and p.P992L heterozygous mutation, respectively, which suggested loss of heterozygosity (LOH). In one family, no mutation was detected in all exons of the ATP7B gene in the patients and their parents. For a triplet, one female was with definite WD and brain symptoms at the onset, one male had subclinical type with WD, whilst another female was completely normal. The triplets and their mother have all carried a p.P992L heterozygous mutation .</p><p><b>CONCLUSION</b>Above results have confirmed an important role for genetic factors in the pathogenesis of WD. In addition to point mutations, LOH is also involved in the pathogenesis for WD.</p>