The measurement of skeletal muscle fatigue in response to cycling exercise is commonly done in isometric conditions, potentially limiting its ecological validity, and creating challenges in monitoring the time course of muscle fatigue across an exercise bout. This study aimed to determine if muscle fatigue could be reliably assessed by measuring quadriceps twitch force evoked while pedaling, using instrumented pedals. Nine participants completed three laboratory visits: a step incremental test to determine power output at lactate threshold, and on separate occasions, two constant-intensity bouts at a power output 10% above lactate threshold. Femoral nerve electrical stimulation was applied to elicit quadriceps twitch force both while pedaling (dynamic) and at rest (isometric). The test-retest reliability of the dynamic twitch forces and the agreement between the dynamic and isometric twitch forces were evaluated. Dynamic twitch force was found to have excellent reliability in an unfatigued state (intraclass correlation coefficient (ICC) = 0.920 and mean coefficient of variation (CV) = 7.5%), and maintained good reliability at task failure (ICC = 0.846 and mean CV = 11.5%). When comparing dynamic to isometric twitch forces across the task, there was a greater relative decline in the dynamic condition (P = 0.001). However, when data were normalized to the 5 min timepoint when potentiation between conditions was presumed to be more similar, this difference disappeared (P = 0.207). The reliability of this method was shown to be commensurate with the gold standard method utilizing seated isometric dynamometers and offers a new avenue to monitor the kinetics of muscle fatigue during cycling in real time.

BACKGROUND: Together with an increased interest in minimally invasive lateral transpsoas approach to the lumbar spine goes a demand for detailed anatomical descriptions of the lumbar plexus. Although definitions of safe zones and essential descriptions of topographical anatomy have been presented in several studies, the existing literature expects standard appearance of the neural structures. Therefore, the aim of this study was to investigate the variability of the extrapsoas portion of the lumbar plexus in regard to the lateral transpsoas approach.
METHODS: A total of 260 lumbar regions from embalmed cadavers were utilized in this study. The specimens were dissected as per protocol and all nerves from the lumbar plexus were morphologically evaluated.
RESULTS: The most common variation of the iliohypogastric and ilioinguinal nerves was fusion of these two nerves (9.6%). Nearly in the half of the cases (48.1%) the genitofemoral nerve left the psoas major muscle already divided into the femoral and genital branches. The lateral femoral cutaneous nerve was the least variable one as it resembled its normal morphology in 95.0% of cases. Regarding the variant origins of the femoral nerve, there was a low formation outside the psoas major muscle in 3.8% of cases. The obturator nerve was not variable at its emergence point but frequently branched (40.4%) before entering the obturator canal. In addition to the proper femoral and obturator nerves, accessory nerves were present in 12.3% and 9.2% of cases, respectively.
CONCLUSIONS: Nerves of the lumbar plexus frequently show atypical anatomy outside the psoas major muscle. The presented study provides a compendious information source of the possibly encountered neural variations during retroperitoneal access to different segments of the lumbar spine.

Continuous adductor canal block (CACB) is almost a pure sensory nerve block and can provide effective analgesia without blocking the motor branch of the femoral nerve. Thus, the objective of this study was to systematically evaluate the efficacy of CACB versus continuous femoral nerve block (CFNB) on analgesia and functional activities in patients undergoing knee arthroplasty. PubMed, Embase and the Cochrane Central Register of Controlled Trials (from inception to 3 October 2023) were searched for randomized controlled trials (RCTs) that compared CACB with CFNB in patients undergoing knee arthroplasty. Registration in the PROSPERO International prospective register of the meta-analysis was completed, prior to initiation of the study (registration number: CRD42022363756). Two independent reviewers selected the studies, extracted data and evaluated risk of bias by quality assessment. Revman 5.4 software was used for meta-analysis and the summary effect measure were calculated by mean differences and 95% confidence intervals. Eleven studies with a total of 748 patients were finally included. Pooled analysis suggested that both CACB and CFNB showed the same degree of pain relief at rest and at motion at 12 h, 24 h and 48 h in patients undergoing knee arthroplasty. Compared with CFNB, CACB preserved the quadriceps muscle strength better (P<0.05) and significantly shortened the discharge readiness time (P<0.05). In addition, there was no significant difference in opioid consumption, knee extension and flexion, timed up and go (TUG) test, or risk of falls between the two groups. Thus, Compared with CFNB, CACB has similar effects on pain relief both at rest and at motion and opioid consumption for patients undergoing knee arthroplasty, while CACB is better than CFNB in preserving quadriceps muscle strength and shortening the discharge readiness time.

BACKGROUND: Femoral nerve block (FNB) is a prevalent method used for postoperative pain management after knee surgery; however, it decreases the strength of the quadriceps muscle and is not conducive to early recovery after surgery. Pectineus muscle plane (PMP) block involves the injection of a local anaesthetic into the fascial plane below the pectineus muscle, where it blocks the obturator and saphenous nerves. However, there is little evidence on the effectiveness of PMP block for analgesia after knee surgery. The aim of this trial is to assess whether PMP block can improve postoperative analgesia, promote early recovery and reduce the length of hospital stay.
METHODS: In this randomised controlled study, 46 patients will be randomly allocated into two groups: the PMP block group (n=23) and the FNB group (n=23). The primary outcome measures will include Visual Analog Scale scores for pain at rest and during movement at various time points following knee surgery. Secondary outcomes will include the degree of active flexion, straight leg raise test performance, get-out-of-bed test result, 20 m walk test result, total dose administered via patient-controlled analgesia infusion pumps, hospital stay duration, patient satisfaction and postoperative complications, such as pulmonary embolism and deep vein thrombosis.This study protocol adheres to rigorous standards for ethical conduct and patient safety. The findings from this trial are expected to contribute valuable insights to the optimisation of postoperative pain management strategies and the improvement of early recovery outcomes for patients who undergo knee surgery.
BACKGROUND: This trial has been approved by the ethics committee of Zhejiang Hospital (2022(128K)) on 17 November 2022, and inpatients who meet the inclusion criteria and diagnostic requirements are eligible for this study. Any subsequent protocol and informed consent document amendments must be approved by the responsible ethics committee. All communications with the regulatory authorities and the ethics committee must be recorded. All recruited patients will be informed of the trial purposes and their duties within the trial before randomisation. Recruited patients can withdraw from the study at any time without providing any specific reason. The patient data will be stored in a separate, safe place, but that it may be reviewed by the relevant investigator. The results will be published in international peer-reviewed medical journals.
BACKGROUND: http://www.chictr.org.cn, ID: ChiCTR2300076018. Registered on 21 September 2023.

UNASSIGNED: Recent findings suggest increased excitatory heteronymous feedback from quadriceps onto soleus may contribute to abnormal coactivation of knee and ankle extensors after stroke. However, there is lack of consensus on whether persons post-stroke exhibit altered heteronymous reflexes and, when present, the origin of increased excitation (i.e. increased excitation alone and/or decreased inhibition). This study examined heteronymous excitation and inhibition from quadriceps onto soleus in paretic, nonparetic, and age-matched control limbs to determine whether increased excitation was due to excitatory and/or reduced inhibitory reflex circuits. A secondary purpose was to examine whether heteronymous reflex magnitudes were related to clinical measures of lower limb recovery, walking-speed, and dynamic balance.
UNASSIGNED: Heteronymous excitation and inhibition from quadriceps onto soleus were examined in fourteen persons post-stroke and fourteen age-matched unimpaired participants. Heteronymous feedback was elicited by femoral nerve and quadriceps muscle stimulation in separate trials while participants tonically activated soleus at 20% max. Fugl-Myer assessment of lower extremity, 10-meter walk test, and Mini-BESTest were assessed in stroke survivors.
UNASSIGNED: Heteronymous excitation and inhibition onsets, durations, and magnitudes were not different between paretic, nonparetic or age-matched unimpaired limbs. Quadriceps stimulation elicited excitation that was half the magnitude of femoral nerve stimulation. Femoral nerve elicited paretic limb heteronymous excitation was positively correlated with walking speed but did not reach significance because only a subset of paretic limbs exhibited excitation (n = 8, Spearman r = 0.69, P = 0.058).
UNASSIGNED: Heteronymous feedback from quadriceps onto soleus assessed in a seated posture was not impaired in persons post-stroke. Despite being unable to identify whether reduced inhibition contributes to abnormal excitation reported in prior studies, our results indicate quadriceps stimulation may allow a better estimate of heteronymous inhibition in those that exhibit exaggerated excitation. Heteronymous excitation magnitude in the paretic limb was positively correlated with self-selected walking speed suggesting paretic limb excitation at the higher end of a normal range may facilitate walking ability after stroke. Future studies are needed to identify whether heteronymous feedback from Q onto SOL is altered after stroke in upright postures and during motor tasks as a necessary next step to identify mechanisms underlying motor impairment.

BACKGROUND: Entrapment or injury of the lateral femoral cutaneous nerve (LFCN) is being recognized with increasing frequency, often requiring a surgical approach to relieve symptoms. The presence of anatomic variations can lead to errors in diagnosis and intraoperative decision-making.
METHODS: This study presents the experience of a single surgeon (T.W.T.) in managing 184 patients referred with clinical issues related to the LFCN. A comprehensive review of these cases was conducted to develop a prospective surgical management algorithm. Data on the LFCN\'s anatomic course, pain relief outcomes, comorbidities, body mass index, and sex were extracted from patients\' medical charts and operative notes. Pain relief was assessed subjectively, categorized into \"excellent relief\" for complete pain resolution, \"good\" for substantial pain reduction with some residual discomfort, and \"failure\" for cases with no pain relief necessitating reoperation.
RESULTS: The decision tree is dichotomized based on the mechanism of LFCN pathology: compression (requiring neurolysis) versus history of trauma, surgery, and/or obesity (requiring resection). Forty-seven percent of the patients in this series had an anatomic variation. It was found that failure to relieve symptoms of compression often indicated the presence of anatomic variation of the LFCN or intraneural changes consistent with a neuroma, even if adequate decompression was achieved. With respect to pain relief as the outcome measure, recognition of LFCN anatomic variability and use of this algorithm resulted in 75% excellent results, 10% good results, and 15% failures. Twenty-seven of the 36 failures originally had neurolysis as the surgical approach. Twelve of those failures had a second surgery, an LFCN neurectomy, resulting in 10 excellent, 1 good, and 1 persistent failure.
CONCLUSIONS: This article establishes an algorithm for the surgical treatment of MP, incorporating clinical experience and anatomical insights to guide treatment decisions. Criteria for considering neurectomy may include a history of trauma, prior local surgery, anatomical LFCN variations, and severe nerve damage due to chronic compression.

OBJECTIVE: To compare the difference in analgesic effect between femoral triangle block (FTB) and adductor canal block (ACB) during arthroscopic knee surgery.
METHODS: Patients who underwent arthroscopic knee surgery were randomized preoperatively to FTB group or ACB group. For each group, 20 mL of 0.1% ropivacaine was injected.
METHODS: The numeric rating score (NRS) at 12 h after surgery at rest and during movement.
RESULTS: (1) The NRS at post anesthesia care unit (PACU) and 2, 24 h after surgery at rest and during movement; (2) The quadriceps muscle strength at PACU and 2, 12, 24 h after surgery; (3) Consumption of Rescue analgesia; (4) Incidence of adverse reactions.
RESULTS: The NRS at 12 h after surgery at rest and during movement of ACB group were higher than FTB group. Among secondary outcomes, the NRS at PACU at rest and during movement, 2 h after surgery during movement of FTB group lower than ACB group; the quadriceps muscle strength at 2 h after surgery of FTB group stronger than ACB group. After multiple linear regression model analysis, the data showed additional statistically significant reduction NRS at 24 h after surgery at rest (0.757, p = 0.037) in FTB group. Other outcomes were similar between two groups.
CONCLUSIONS: The FTB appears to provide superior pain control after knee arthroscopy than ACB, the FTB is superior to the ACB in quadriceps muscle strength at 2 h after surgery.
BACKGROUND: The trial was registered in the Chinese Clinical Trial Registry (ChiCTR2300068765). Registration date: 28/02/2023.

Objective.Electrical stimulation of peripheral nerves has long been a treatment option to restore impaired neural functions that cannot be restored by conventional pharmacological therapies. Endovascular neurostimulation with stent-mounted electrode arrays is a promising and less invasive alternative to traditional implanted electrodes, which typically require invasive implantation surgery. In this study, we investigated the feasibility of endovascular stimulation of the femoral nerve using a stent-mounted electrode array and compared its performance to that of a commercially available pacing catheter.Approach.In acute animal experiments, a pacing catheter was implanted unilaterally in the femoral artery to stimulate the femoral nerve in a bipolar configuration. Electromyogram of the quadriceps and electroneurogram of a distal branch of the femoral nerve were recorded. After retrieval of the pacing catheter, a bipolar stent-mounted electrode array was implanted in the same artery and the recording sessions were repeated.Main Results.Stimulation of the femoral nerve was feasible with the stent-electrode array. Although the threshold stimulus intensities required with the stent-mounted electrode array (at 100-500µs increasing pulse width, 2.17 ± 0.87 mA-1.00 ± 0.11 mA) were more than two times higher than the pacing catheter electrodes (1.05 ± 0.48 mA-0.57 ± 0.28 mA), we demonstrated that, by reducing the stimulus pulse width to 100µs, the threshold charge per phase and charge density can be reduced to 0.22 ± 0.09µC and 24.62 ± 9.81µC cm-2, which were below the tissue-damaging limit, as defined by the Shannon criteria.Significance.The present study is the first to reportin vivofeasibility and efficiency of peripheral nerve stimulation using an endovascular stent-mounted electrode array.

UNASSIGNED: To compare the effect of sciatic nerve block (SNB) combined with continuted femoral nerve block (FNB) or continuted adductor canal block (ACB) on pain and motor function after total knee arthroplasty (TKA).
UNASSIGNED: A total of 60 patients with TKA-treated osteoarthritis of the knee who met the selection criteria were enrolled between November 2020 and February 2021 and randomised allocated into the study group (SNB combined with continuted ACB) and the control group (SNB combined with continuted FNB), with 30 cases in each group. There was no significant difference in gender, age, body mass, height, body mass index, preoperative Hospital for Special Surgery (HSS) score, femoral tibial angle, and medial proximal tibial angle between the two groups ( P>0.05). The operation time, the initial time to the ground, the initial walking distance, and the postoperative hospital stay were recorded. At 2, 4, 6, 12, 24, and 48 hours after operation, the numerical rating scale (NRS) score was used to evaluate the rest pain around the knee joint, the quadriceps femoris muscle strength was evaluated by the freehand muscle strength method, and the knee flexion and extension angles were measured.
UNASSIGNED: There was no significant difference in the operation time and initial walking distance between the two groups ( P>0.05); the initial time to the ground and postoperative hospital stay of the study group were significantly shorter than those of the control group ( P<0.05). Except for the 48-hour postoperative NRS score of the study group, which was significantly lower than that of the control group ( P<0.05), there was no significant difference in the NRS scores between the two groups at the remaining time points ( P>0.05). The quadriceps femoris muscle strength from 4 to 24 hours postoperatively and the knee extension angle from 2 to 6 hours postoperatively of the study group were significantly better than those of the control group ( P<0.05); the differences in the quadriceps femoris muscle strength and knee extension and flexion angles between the two groups at the remaining time points were not significant ( P>0.05).
UNASSIGNED: SNB combined with either continuted ACB or continuted FNB can effectively relieve pain in patients after TKA, and compared with combined continuted FNB, combined continuted ACB has less effect on quadriceps femoris muscle strength, and patients have better recovery of knee flexion and extension mobility.
UNASSIGNED: 比较坐骨神经阻滞（sciatic nerve block，SNB）联合持续股神经阻滞（femoral nerve block，FNB）或持续收肌管阻滞（adductor canal block，ACB）对人工全膝关节置换术（total knee arthroplasty，TKA）术后疼痛和运动功能的影响。.
UNASSIGNED: 共纳入2020年12月—2021年2月收治且符合选择标准的60例行TKA治疗的膝关节骨关节炎患者，随机分为研究组（SNB联合持续ACB）和对照组（SNB联合持续FNB），每组30例。两组患者性别、年龄、体质量、身高、身体质量指数及术前膝关节美国特种外科医院（HSS）评分、胫股角、胫骨近端内侧角等基线资料比较差异均无统计学意义（ P>0.05）。记录手术时间、初次下地时间、初次行走距离、术后住院时间；术后2、4、6、12、24、48 h，采用数字评分量表（NRS）评价患者膝关节周围静息疼痛情况，采用徒手肌力法评价股四头肌肌力变化，并测量膝关节屈曲及伸直角度。.
UNASSIGNED: 两组患者手术时间和初次行走距离比较差异无统计学意义（ P>0.05）；研究组初次下地时间和术后住院时间均明显短于对照组，差异有统计学意义（ P<0.05）。除术后48 h研究组NRS评分低于对照组（ P<0.05）外，其余时间点两组NRS评分比较差异无统计学意义（ P>0.05）。术后4～24 h研究组股四头肌肌力及2～6 h膝关节伸直角度均优于对照组，差异有统计学意义（ P<0.05）；其余时间点两组股四头肌肌力和膝关节屈伸角度比较差异均无统计学意义（ P>0.05）。.
UNASSIGNED: SNB联合持续ACB或持续FNB均可有效缓解TKA术后患者疼痛，与联合持续FNB相比，联合持续ACB对股四头肌肌力影响更小，患者膝关节屈伸活动恢复更好。.

Evaluating reciprocal inhibition of the thigh muscles is important to investigate the neural circuits of locomotor behaviors. However, measurements of reciprocal inhibition of thigh muscles using spinal reflex, such as H-reflex, have never been systematically established owing to methodological limitations. The present study aimed to clarify the existence of reciprocal inhibition in the thigh muscles using transcutaneous spinal cord stimulation (tSCS). Twenty able-bodied male individuals were enrolled. We evoked spinal reflex from the biceps femoris muscle (BF) by tSCS on the lumber posterior root. We examined whether the tSCS-evoked BF reflex was reciprocally inhibited by the following conditionings: (1) single-pulse electrical stimulation on the femoral nerve innervating the rectus femoris muscle (RF) at various inter-stimulus intervals in the resting condition; (2) voluntary contraction of the RF; and (3) vibration stimulus on the RF. The BF reflex was significantly inhibited when the conditioning electrical stimulation was delivered at 10 and 20 ms prior to tSCS, during voluntary contraction of the RF, and during vibration on the RF. These data suggested a piece of evidence of the existence of reciprocal inhibition from the RF to the BF muscle in humans and highlighted the utility of methods for evaluating reciprocal inhibition of the thigh muscles using tSCS.