Reliability of Power Spectral Analysis of Surface Electromyogram Recorded during Sustained Vastus Medialis Isometric Contraction in Assessment of Muscle Fatigability

The aim of this study was to determine the within-day and between-days reliability of surface electromyographic (EMG) power spectral analysis in assessing fatigability of the vastus medialis (VM) muscle during knee and hip flexion under constant load application. The subjects were 13 healthy adult men free of knee abnormalities. Surface EMG was recorded from vastus medialis obliquus (VMO) and vastus medialis longus (VML) during sustained isometric contractions at 60% of maximal voluntary contraction until exhaustion on the leg press machine (static leg press test). Linear regression analysis was applied to median frequency (MF) time series to calculate initial MF and MF slope. For VMO and VML, the initial MF showed moderate to high reliability, while the MF slope showed high reliability (Intraclass correlation coefficient (ICC) = initial MF: 0.63 - 0.92, MF slope: 0.70 - 0.86). The results demonstrated that spectral analysis of surface EMG recording during isometric VM muscle contraction has high within-day and between-days reliability in the assessment of fatigability of the VMO and VML.

Osteotomy of the Margo Medialis Scapulae to Approach Subscapular and Subrhomboid Tumors. A Technical Note

Purpose: The approach to resect subscapular and subrhomboid tumors needs elevation of the scapula. This is usually performed by detaching the muscles from the margo medialis of the scapula. We wish to communicate our technique of a longitudinal osteotomy of the margo medialis for improved refixation of the muscles. Patients and Methods: 5 patients with subscapular and one patient with a subrhomboid benign tumor were operated on using this technique. Results: All patients achieved stable healing and full functional recovery;only in one patient there was slightly reduced elevation of the arm. Conclusion: Elevation of the muscles inserting into the medial scapular margo with a small rim of bone facilitates refixation and allows for excellent restitution of function.

Combination of medial patellofemoral ligament reconstruction with vastus medialis advancement for chronic patellar dislocation

Background The medial patellofemoral ligament （MPFL） reconstruction is popular in clinical practice for chronic patellar dislocation; however, the combination with vastus medialis advancement is rare. The aim of this study was to evaluate the clinical outcome of the combination of MPFL reconstruction with vastus medialis advancement.Methods We retrospectively analyzed 69 patients with chronic patellar dislocation between July 2004 and October 2008： twenty eight cases with isolated MPFL reconstruction （group Ⅰ）, forty one cases with the combination of MPFL reconstruction with vastus medialis advancement （group C）. All patients had CT scans available for review with knee flexion at 30 degree, on which the congruence angle, patellar tilt angle and patellar lateral shift were measured. Physical apprehension tests were examined and the redislocation was recorded. In addition, knee function was evaluated using the Kujala score and subjective questionnaires.Results Patients were followed up for a mean of 42 months （12-65 months） without a recurrent dislocation reported.Postoperatively, all indexes on CT scan were within the normal range without a statistical difference between the two groups. Results from the apprehension test showed eight patients in group Ⅰ and three in group Chad patellar lateral shift exceeding 1.5 cm with a hard end point （P 〈0.05）. The Kujala score improved significantly from 51.3±4.5 to 79.9±6.2 in group Ⅰ and from 53.7±5.2 to 83.9±6.5 in group C （P 〉0.05）. However, the subjective questionnaire revealed a significant difference （P 〈0.05）, including 12 excellent, seven good and nine fair in group Ⅰ and 30 excellent, six good and five fair in group C.Conclusion The combination of MPFL reconstruction with vastus medialis advancement is better than isolated reconstruction to improve the subjective effects and decrease the patellar instability rate for chronic patellar dislocation.

Significance of Diffusion Tensor Imaging of Vastus Medialis Oblique in Recurrent Patellar Dislocation

Background： Numerous studies have investigated the influence of osseous factors on patellofemoral joint instability, but research on the influence of dynamic muscle factors in vivo is still in the exploratory stage. This study aimed to use magnetic resonance imaging （MRI） and diffusion tensor imaging （DTI） to evaluate vastus medialis oblique （VMO） fiber bundles in patients with recurrent patellar dislocation to explore the changes in muscle morphology and function. Methods： This prospective study involved 30 patients （7 males and 23 females; average age, 21.4 ± 3.8 years） clinically diagnosed with recurrent patellar dislocation in Peking University Third Hospital and 30 healthy volunteers matched for age, sex, and body mass index in our medical school between January 2014 and October 2014. None of the patients had a recent history of traumatic patellar dislocation or transient patellar dislocation. All patients underwent conventional MRI and DTI of the knee. The cross-sectional area of the VMO on MRI and the fractional anisotropy （FA）, apparent diffusion coefficient （ADC）, and primary （λ1）, secondary （λ2）, and three-level characteristic （λ3） values on DTI were measured. The independent-samples t-test was used to compare these parameters between the two groups. Results： Compared with the control group, the patient group showed significantly higher FA values （0.39 ± 0.05 vs. 0.33 ± 0.03） and significantly lower ADC （1.51 ± 0.13 vs. 1.58± 0.07）, λ2 （4.96 ±0.13 vs. 5.04 ± 0.07）, and λ3 values （4.44 ± 0.14 vs. 4.58 ± 0.07; t = 5.99, t = -2.58, t = 3.02, and t = -4.88, respectively： all P 〈 0.05）. Cross-sectional VMO area and λ1 values did not differ between the two groups （t = 1.82 and t = 0.22, respectively; both P 〉 0.05）. Conclusions： The functional status of the VMO is closely associated with recurrent patellar dislocation. MRI, especially DTI （FA, ADC, λ2, and ,λ3）, can detect early changes in VMO function and might lhcilitate the noninvasive monitoring of the functional status of the VMO in patients with recurrent patellar dislocation.

稻纵卷叶螟抗药性研究进展

简述了稻纵卷叶螟(Cnaphalocrocis medialis Guenee)对杀虫剂抗性的发展、抗药性形成及其影响因素、抗药性机理与治理策略等方面的研究。

Posterolateral dislocation of the knee:Recognizing an uncommon entity

Posterolateral dislocations of the knee are rare injuries.Early recognition and emergent open reduction is crucial.A 48-year-old Caucasian male presented with right knee pain and limb swelling 3 d after sustaining a twisting injury in the bathroom.Examination revealed the pathognomonic anteromedial "pucker" sign.Anklebrachial indices were greater than 1.0 and symmetrical.Radiographs showed a posterolateral dislocation of the right knee.He underwent emergency open reduction without an attempt at closed reduction.Attempts at closed reduction of posterolateral dislocations of the knee are usually impossible because of incarceration of medial soft tissue in the intercondylar notch and may only to delay surgical management and increase the risk of skin necrosis.Magnetic resonance imaging is not crucial in the preoperative period and can lead to delays of up to 24 h.Instead,open reduction should be performed once vascular compromise is excluded.

End-to-side neurorrhaphy repairs peripheral nerve injury：sensory nerve induces motor nerve regeneration

End-to-side neurorrhaphy is an option in the treatment of the long segment defects of a nerve.It involves suturing the distal stump of the disconnected nerve（recipient nerve） to the side of the intimate adjacent nerve（donor nerve）.However,the motor-sensory specificity after end-to-side neurorrhaphy remains unclear.This study sought to evaluate whether cutaneous sensory nerve regeneration induces motor nerves after end-to-side neurorrhaphy.Thirty rats were randomized into three groups：（1） end-to-side neurorrhaphy using the ulnar nerve（mixed sensory and motor） as the donor nerve and the cutaneous antebrachii medialis nerve as the recipient nerve;（2） the sham group：ulnar nerve and cutaneous antebrachii medialis nerve were just exposed;and（3） the transected nerve group：cutaneous antebrachii medialis nerve was transected and the stumps were turned over and tied.At 5 months,acetylcholinesterase staining results showed that 34% ± 16% of the myelinated axons were stained in the end-to-side group,and none of the myelinated axons were stained in either the sham or transected nerve groups.Retrograde fluorescent tracing of spinal motor neurons and dorsal root ganglion showed the proportion of motor neurons from the cutaneous antebrachii medialis nerve of the end-to-side group was 21% ± 5%.In contrast,no motor neurons from the cutaneous antebrachii medialis nerve of the sham group and transected nerve group were found in the spinal cord segment.These results confirmed that motor neuron regeneration occurred after cutaneous nerve end-to-side neurorrhaphy.