Long head of biceps tendon transposition for massive and irreparable rotator cuff tears:A systematic review and meta-analysis

BACKGROUND Superior capsular reconstruction(SCR)with long head of biceps tendon(LHBT)transposition was developed to massive and irreparable rotator cuff tears(MIRCTs);however,the outcomes of this technique remain unclear.AIM To perform a systematic review of biomechanical outcomes and a meta-analysis of clinical outcomes after LHBT transposition for MIRCTs.METHODS We performed a systematic electronic database search on PubMed,EMBASE,and Cochrane Library.Studies of SCR with LHBT transposition were included according to the inclusion and exclusion criteria.Biomechanical studies were assessed for main results and conclusions.Included clinical studies were evaluated for quality of methodology.Data including study characteristics,cohort demographics,and outcomes were extracted.A meta-analysis was conducted of the clinical outcomes.RESULTS According to our inclusion and exclusion criteria,a total of six biomechanical studies were identified and reported an overall improvement in subacromial contact pressures and prevention of superior humeral migration without limiting range of motion(ROM)after LHBT transposition for MIRCTs.A total of five clinical studies were included in the meta-analysis of LHBT transposition outcomes,consisting of 253 patients.The results indicated that compared to other surgical methods for MIRCTs,LHBT transposition had advantages of more significant improvement in ROM(forward flexion mean difference[MD]=6.54,95%confidence interval[CI]:3.07-10.01;external rotation[MD=5.15,95%CI:1.59-8.17];the acromiohumeral distance[AHD][MD=0.90,95%CI:0.21-1.59])and reducing retear rate(odds ratio=0.27,95%CI:0.15-0.48).No significant difference in American Shoulder and Elbow Surgeons score,visual analogue scale score,and University of California at Los Angles score was demonstrated between these two groups for MIRCTs.CONCLUSION In general,SCR with LHBT transposition was a reliable and economical technique for treating MIRCTs,both in terms of biomechanical and clinical outcomes,with comparable clinical outcomes,improved ROM,AHD,and reduced the retear rates compared to conventional SCR and other established techniques.More high-quality randomized controlled studies on the long-term outcomes of SCR with LHBT transposition are required to further assess.

Hot-electron deposition and implosion mechanisms within electron shock ignition

A hot-electron driven scheme can be more effective than a laser-driven scheme within suitable hot-electron energy and target density. In our one-dimensional (1D) radiation hydrodynamic simulations, 20× pressure enhancement was achieved when the ignitor laser spike was replaced with a 60-keV hot-electron spike in a shock ignition target designed for the National Ignition Facility (NIF), which can lead to greater shell velocity. Higher hot-spot pressure at the deceleration phase was obtained owing to the greater shell velocity. More cold shell material is ablated into the hot spot, and it benefits the increases of the hot-spot pressure. Higher gain and a wider ignition window can be observed in the hot-electron-driven shock ignition.

Long-term Outcome of Multiple Small-diameter Drilling Decompression Combined with Hip Arthroscopy versus Drilling Alone for Early Avascular Necrosis of the Femoral Head

Background： Avascular necrosis of femoral head （AVNFH） typically presents in the young adults and progresses quickly without proper treatments. However, the optimum treatments for early stage of AVNFH are still controversial. This study was conducted to evaluate the therapeutic effects of multiple small-diameter drilling decompression combined with hip arthroscopy for early AVNFH compared to drilling alone. Methods： This is a nonrandomized retrospective case series study. Between April 2006 and November 2010, 60 patients （98 hips） with early stage AVNFH participated in this study. The patients underwent multiple small-diameter drilling decompression combined with hip arthroscopy in 26 cases/43 hips （Group A） or drilling decompression alone in 34 cases/55 hips （Group B）. Patients were followed up at 6, 12, and 24 weeks, and every 6 months thereafter. Radiographs were taken at every follow-up, Harris scores were recorded at the last follow-up, the paired t-test was used to compare the postoperative Harris scores. Surgery effective rate of the two groups was compared using the Chi-square test. Results： All patients were followed up for an average of 57.6 months （range： 17-108 months）. Pain relief and improvement of hip function were assessed in all patients at 6 months after the surgery. At the last follow-up, Group A had better outcome with mean Harris＇ scores improved from 68.23 ± 11.37 to 82.07 ± 2.92 （t = -7.21, P = 0.001） than Group B with mean Harris＇ scores improved from 69.46 ± 9.71 to 75.79± 4.13 （t = -9.47, P = 0.037） （significantly different： t = -2.54, P = 0.017）. The total surgery effective rate was also significantly different between Groups A and B （86.0% vs. 74.5%; Z2 = 3.69, P = 0.02）. Conclusion： For early stage of AVNFH, multiple small-diameter drilling decompression combined with hip arthroscopy is more effective than drilling decompression alone.