糖皮质激素在成人呼吸窘迫综合征救治中的合理应用

采用放射配体结合法测定２８例成人呼吸窘迫综合征（ＡＲＤＳ）病人外周血白细胞糖皮质激素受体（ＧＣＲ），结果（１０１８．３±８２５．２）位点／细胞，显著低于正常人（４６３４．１±４３６．５）位点／细胞（Ｐ＜０．０１）。而其血浆皮质醇浓度为（２８９±１５１）ｕｇ／Ｌ，高于正常人（１２４±４７）ｕｇ／Ｌ（Ｐ＜０．０５）。结合病人ＡＰＡＣＨＥⅡ评分，并根据ＧＣＲ指导地塞米松的用法，使ＡＲＤＳ的病死率由８８．３％下降至３６。４％。     

神经节苷酯对低氧大鼠脑钙,钙调素及蛋白激酶Ⅱ的影响

观察了神经节苷酯对急性低氧组大鼠（Ａ组：模拟海拔７００ｍ，５ｈ；Ｂ组：给神经节苷酯）和常氧对照组大鼠（Ｃ组：常氧；Ｄ组：给神经节苷酯）脑组织Ｃａ￣（２＋）、钙调素（ＣａＭ）及ＣａＭ依赖性蛋白激酶Ⅱ（ＣａＭＰＫⅡ）活性的影响。用Ｆｕｒａ－２测得Ｃａ￣（２＋）水平分别为７２２．１±８１．２．６４０．６±７４．４、２５８。７±３９．２和２６３．８±４１．３ｎｍｏｌ／Ｌ，Ａ组明显高于常氧对照组（Ｐ＜０．０１）；Ｂ组明显低于Ａ组（Ｐ＜＜０．０５）。用流式细胞仪（ＦＡＣＳ）所测ＣａＭ平均荧光强度分别为４０．２±４．７、４４．３±４．８．４６．１±５．１和４５．９±５．０道；Ａ组明显低于常氧对照组。用同位素（ｒ￣（３２）－ＡＴＰ）液闪计数法所测ＣａＭＰＫⅡ活性分别为１８２．９±７．９、１９２．３±８．２、１９７．９±９．２和１９８．２±９．３ｐｍｏｌｐｉ．ｍｉｎ￣（－１）ｍｇ￣（－１）ｐｒｏｔｅｉｎ，Ａ组明显低于其它三组，急性低氧Ｂ组与常氧对照组比无明显差别。表明，低氧时神经节苷酯可以减少胞内Ｃａ￣（２＋）蓄积和稳定ＣａＭ和ＣａＭＫｉｎａｓｅⅡ的变化．     

G-CSF减轻大鼠下肢缺血再灌注致肺功能损伤的实验研究

目的：研究重组粒细胞集落刺激因子（Ｇ－ＣＳＦ）对大鼠下肢缺血再灌注所致肺功能损伤的治疗作用。方法：雄性ＳＤ大鼠随机分３组,手术组及给药组麻醉后开腹解剖口主动脉．在肾动脉水平远端阻断１２０ｍｉｎ,开放、再灌注 １２０ ｍｉｎ;假手术组不阻断腹主动脉,余同手术组。３组均于术前经舌静脉注入伊文氏蓝（Ｅｖａｎ’ｓ ｂｌｕｅ ｄｇｅ） ３０ ｍｇ／ｋｇ;给药组术前经尾赢脉注入Ｇ－ＣＳＦ ２０μｇ／ｋｇ．余二组给予生理盐水１ｍｌ。术后取肺组织测定丙二醛（ｍａｌｏｎｒｌｄｉａｄｅｈｙｄｅ,ＭＤＡ）及伊文氏蓝含量。结果：给药组ＭＤＡ含量为（１．７１±０．３４）ｎｍｏｌ／ｍｇ,假手术组为（ｌ．７３±０．６５）ｎｍｏｌ／ｍｇ,均显著低于手术组〔（２．５４±０．３９）ｎｍｏｌ／ｍｇ］。 给药组伊文氏蓝含量为（１．５０±０．２９）μｇ／ｍｇ．假手术组为（０．１３±０．０７）μｇ／ｍｇ,均显著低于手术组［（（３．０７±１．１８）μｇ／ｍｇ］．结论：Ｇ－ＣＳＦ有减轻大鼠下肢缺血再灌注所致肺功能损伤的作用。     

心肌肌凝蛋白轻链放射免疫分析及临床初步应用

为提供急性心肌梗塞（ＡＭＩ）早期血清学诊断法，用改进后的Ｓｃｈｏβ法提取狗肌凝蛋白轻链（ＣＭ－ＬＣ），免疫兔获得抗血清。氯胺Ｔ法标记抗原，建立血清ＣＭ－ＬＣ ＲＩＡ。结果：该方法标准曲线测量范围１－１００μｇ／Ｌ，批内、批间（ＣＶ分别是３．２％和９．１％，平均回收率９５．３％。正常人３０例血清ＣＭ－ＬＣ为３．５±１．５μｇ／Ｌ，２０例ＡＭＩ患 者血清ＣＭ＝ＬＣ为２０．２±８．６μｇ／Ｌ，两组间差异     

ApoE基因敲除鼠12周游泳运动前后纤溶激活功能的改变

目的：探讨ＡｐｏＥ在长期有氧运动中影响纤溶激活作用中的有关机制。方法：以ＡｐｏＥ基因敲除（ＡｐｏＥ－／－）鼠为实验组、以相同遗传背景的Ｃ５７ＢＬ／６Ｊ鼠为对照组建立运动模型。结果：１２周游泳后，对照组鼠ＴＧ（０．９６±０．３０ｖｓ０．５４±０．０７０ｍｍｏｌ／Ｌ，Ｐ＜０．０１）和ＰＡＩ（０．９２±０．０７ｖｓ０．８０±０．０９ＡＵ／ｍｌ，Ｐ＜０．０５）降低，ｔＰＡ升高（０．６０±０．１２ｖｓ１．０４±０．２３ＩＵ／ｍｌ，Ｐ＜０．０１）；而ＡｐｏＥ－／－鼠的ＴＧ（１．２８±０．３４ｖｓ１．２９±０．３２ｍｍｏｌ／Ｌ，Ｐ＞０．０５）和ＰＡＩ（０．７４±０．１０ｖｓ０．７９±０．０４ＡＵ／ｍｌ，Ｐ＞０．０５）均没有显著变化，ｔＰＡ（０．７１±０．１５ｖｓ０．９７±０．１７ＩＵ／ｍｌ，Ｐ＜０．０１）升高。结论：长期有氧运动使对照小鼠纤溶激活作用明显改善，其机制与ＴＧ和含ＡｐｏＥ脂蛋白水平降低导致ＬＲＰ清除ｔＰＡ－ＰＡＩ作用加强、ＰＡＩ抑制作用减弱及ｔＰＡ合成水平增加有关。Ａｐ ｏＥ－／－鼠运动后，ＰＡＩ水平稳定而ｔＰＡ活性增加，提示ｔＰＡ合成作用增强。     

HLA配型相合母子间移植1例

本文报告了１例母子间外周血干细胞移植病例。供受者ＨＬＡ表型完全相合．但供者ＣＭＶ—ＩｇＧ（＋）,ＩｇＭ（＋）。预处理为全身照射（ＴＢＩ）加环磷酰胺（ＣＹ）方案,环孢素Ａ（ＣＳＡ）加甲氨喋呤（ＭＴＸ）方案预防ＧＶＨＤ。输入ＭＮＣ ３．３×１０３／ｋｇ,ＣＤ３４＋ＣＤ３８—１１．８×１０６／ｋｇ。ＷＢＣ下降到最低点（０．１×１０９／Ｌ）为移植后第７天,血小板下降到最低点（７×１０９／Ｌ）为第８天。ＷＢＣ超过１．０×１０９／Ｌ为第１９天,血小板达到２０×１０９／Ｌ上下为第２５天。移植后第３０天、５８天两次行细胞遗传学检查,结果均为４６（Ｘ,Ｘ）。移植后产生了ＩＶ度ａＧＶＨＤ和ＣＭＶ间质性肺炎,经积极治疗后均得到控制。移植后已近２年,现血象基本正常,有局限性ｃＧＶＨＤ表现。仍在服用环胞素Ａ胶囊中。本文对二代间移植的相关问题进行了讨论。     

丙二醛及D-二聚体水平在脑梗塞时的变化

为探讨急性脑梗塞时患者体内 脂质过氧化及纤溶状况，以指导临床诊疗。用硫代巴比妥酸比色法和酶联免疫吸附双抗体夹心法分别测定了患者丙二醛（ Ｍ Ｄ Ａ） 及 Ｄ 二聚体（ Ｄ ｄｉｍ ｅｒ） 水平，结果在急性脑梗塞时 Ｍ Ｄ Ａ 为（７１ ±１ ．４）ｎｍ ｏｌ／ Ｌ，较正常人（６ ．０±１ ．３）ｎ ｍｏｌ／ Ｌ 明显地升高（ Ｐ＜ ０ ．０１） ， Ｄ ｄｉｍｅｒ 在急性脑梗塞时为（１ ．７２ ±０ ．９８） ｍ ｇ／ Ｌ 较正常人（０ ．２６ ±０ ．１３） ｍｇ／ Ｌ 也明显地升高（ Ｐ＜ ０ ．０１） 。提示脑梗塞时机体内存在脂质过氧化及纤溶活性的增强，适当予以抗氧化及溶栓治疗是降低病人死亡率，提高治愈率的一项有效措施。     

高原低氧性肺动脉高压的多普勒超声研究

应用脉冲式或连续式多普勤超声技术，对１８例海拔３２００ｍ高原正常人及２５例高原性心脏病（ＨＡＨＤ）患者测定其肺动脉压。正常组及ＨＡＨＤ无瓣膜返流组１０例（４０％）应用Ｈａｈａｍ回归方程，ＰＡＭＰ分别为２．８４±０．４及３．７３±０．５７（ｌｋＰａ＝７．５ｍｍＨｇ）；ＨＡＨＤ有三尖瓣返流组８例（３２％）用ＴＲＰＧ法测得ＰＡＳＰ为６．１３±１．７３ｋＰａ；ＨＡＨＤ有肺动脉瓣返流组７例（２８％）用ＰＲＰＧ法测得ＰＡＤＰ为４．０±０．７３ｋＰａ。表明多普勒超声技术的不同方法可用于不同病理状态上高原低氧性肺动脉高压的测定，并揭示了出现瓣膜返流改变时高原低氧性肺动脉高压的程度。     

采用Seldinger技术锁骨下动脉穿刺插管的解剖学基础及临床应用研究

经皮锁骨下动脉（ＳＣＡ）穿刺是导管药盒系统植入术的难点之一。对１２例成人尸体标本双侧ＳＣＡ走行及毗临关系解剖学观察表明，ＳＣＡ的体表投影点（Ｄ点）位于胸锁关节与喙突连线中点偏外约１ｃｍ处。当动脉的穿刺靶点为Ｄ点内１．５ｃｍ上约１ｃｍ处时，在锁骨中外１／３下２～３ｃｍ处进针，角度额状面为（２０～３０）°，横断面为（１０～２０）°，深度为４～５ｃｍ。２０例患者穿刺成功并送入导丝后的Ｘ线照片测量显示左ＳＣＡ位于第一肋外缘中点处，可作为透视下定位点和靶点。ＳＣＡ穿刺先按体表标志进行，困难时按透视下骨性标志进行，不成功则采取经股动脉插管，入左ＳＣＡ，透视引导下穿刺。     

99Tcm-MIBI心肌断层显像用于直接PTCA及静脉溶栓治疗AMI的对比研究

目的　比较直接经皮冠状动脉腔内成形术（ 直接ＰＴＣＡ） 和静脉溶栓疗法在急性心肌梗死（ＡＭＩ） 治疗中的效果。方法　１２４ 例ＡＭＩ患者（ 直接ＰＴＣＡ组６０ 例,溶栓组６４ 例） 均于发病２ 周时和１２ 周后行９９Ｔｃｍ甲氧基异丁基异腈（ＭＩＢＩ）心肌断层显像,将左室心肌分为２０ 个节段,并对心肌摄取９９ＴｃｍＭＩＢＩ的程度进行打分,分别计算发病２ 周时心肌显像的总积分（Ｓ２ＷＳ） 、发病后１２ 周心肌显像的总积分（Ｓ１２ＷＳ）和两者相减的积分（ＳＤＳ）。直接ＰＴＣＡ组和溶栓组分别有３８ 人和３５ 人于心肌显像后行平衡法门控心室显像。结果　直接ＰＴＣＡ 组与溶栓组比较：Ｓ２ＷＳ为１８－３±６－９ 和２８－６ ±７－３（ｔ＝７－３,Ｐ＜ ０－００１）,Ｓ１２ＷＳ为１１－２ ±４－２ 和２４－４ ±６－２（ｔ＝ １１－７,Ｐ＜ ０－００１）,ＳＤＳ为７－６ ±３－２ 和４－３ ±１－１（ｔ＝ ５－４,Ｐ＜ ０－００１）。直接ＰＴＣＡ组和溶栓组入院２ 周时的左室射血分数（ＬＶＥＦ） 分别为（４１－４ ±６－５） ％ 和（３９－５ ±７－２）％ （ｔ＝ １－５ ,Ｐ＞ ０－０５）,出院１２ 周后的ＬＶＥＦ 分别为（６２－６ ±７－８）％ 和（５１－４ ±     

The effect of knee flexion and rotation on the tibial tuberosity–trochlear groove distance

Purpose

The purpose was to measure the effect of flexion and additional rotation of the femur relative to the tibia on the tuberosity–trochlear groove distance (TT–TG) in the same subject in 20 cadaveric knees joint.

Methods

In 20 human adult cadavers, formal fixed knees (age: 81.9 years, SD 12.3; 10 female) CT scans were performed in extension and 30° of flexion as well as in neutral, maximal possible internal (IR), and external rotation (ER). On superimposed CT scan images, TT–TG was measured in each position. TT–TG measurements were correlated in all knee positions.

Results

TT–TG in full extension/neutral rotation was 7.8 mm (SD 3.4, range, 2.4–15.3). TT–TG in full extension and IR was significantly lower, and TT–TG in full extension and ER was significantly higher than in neutral rotation (5.4 ± 2.3 vs. 10.9 ± 4.8 mm; P < 0.001). IR and ER varied between 1.0°–7.6° and 0.2°–9.2°, respectively. TT–TG in 30° flexion/neutral rotation was 3.9 mm (SD 1.8, range, 1.3–7.8), which was significantly lower than in full extension and neutral rotation (P < 0.001). TT–TG in 30° flexion and IR was significantly lower, and TT–TG in 30° flexion and ER was significantly higher than values obtained in neutral rotation (2.7 ± 1.2 vs. 6.5 ± 3.4 mm; P < 0.001). IR and ER in 30° flexion varied between 0.6°–10.7° and 1.9°–13.0°, respectively.

Conclusion

Flexion as well as rotation of the knee joint significantly alters the TT–TG. These results may have wider clinical relevance in assessing TT–TG and further decisions based on it.

     

Extension gap needs more than 1-mm laxity after implantation to avoid post-operative flexion contracture in total knee arthroplasty

Purpose

In total knee arthroplasty (TKA), a high soft-tissue tension in extension at the time of operation would cause a post-operative flexion contracture. However, how tight the extension gap should be during surgery to avoid a post-operative flexion contracture remains unclear. The hypothesis is that some laxity in the intraoperative extension gap is necessary to avoid the post-operative flexion contracture.

Methods

A posterior-stabilized TKA was performed for 75 osteoarthritic knees with a varus deformity. The intraoperative extension gap was measured using a tensor device that provides the gap length and the angle between the femoral component and the tibial cut surface. The medial component gap was defined as the gap calculated by subtracting the selected thickness of the tibial component, including the polyethylene liner, from the extension gap at the medial side. Then, the patients were divided into three groups according to the medial component gap, and post-operative extension angle measured 1 year after the surgery was compared between each groups.

Results

One year post-operatively, a flexion contracture of more than 5° was found in 0/34 patients when the medial component gap was more than 1 mm, in 2/26 (8 %) patients when the gap was between 0 and 1 mm, and in 3/15 (20 %) patients when the gap was <0 mm. Three factors were associated significantly with the post-operative extension angle: age, preoperative extension angle, and medial component gap.

Conclusion

The intraoperative extension gap is related to the post-operative extension angle. Surgeons should leave more than 1-mm laxity after the implantation to avoid the post-operative flexion contracture. As a clinical relevance, this study clarified the optimal extension gap to avoid the post-operative flexion contracture.

Level of evidence

Prospective comparative study, Level II.     

不同跖屈角度对踝三角韧带损伤X线诊断的影响

目的 评估踝关节不同跖屈角度对踝三角韧带损伤X线诊断的影响,提高踝三角韧带损伤诊断的准确率.方法 自2010年2月至2010年12月收治踝关节旋后-外旋型骨折患者24例,均为腓骨远端骨折但无内踝骨折.所有患者外翻应力下分别取中立位0°、跖屈位15°、30°、45°拍摄踝穴位X线片,并行患侧踝关节MRI检查.对不同跖屈角度下四组患者X线片内侧踝穴宽度(medial clear space,MCS)及胫距上关节宽度(superior clear space,SCS)进行测量.测量结果采用单因素方差分析LSD-t检验,分别以(1)MCS≥4 mm,且MCS＞ SCS,(2)MCS≥5 mm,且MCS＞ SCS作为踝三角韧带损伤X线诊断的标准,踝关节MRI检查结果作为诊断“金标准”,进行诊断性试验研究.结果 外翻应力下踝关节中立位0°、跖屈位15°、30°、45°时,MCS测量结果分别为(4.10±0.79)mm、(4.55±0.72)mm、(4.99±0.56)mm、(5.71 +0.86)mm,组间比较差异有统计学意义(P＜0.05);SCS测量结果分别为(3.56±0.41)mm、(3.50±0.43)mm、(3.71±0.44)mm、(3.93±0.51)mm,组间比较差异无统计学意义(P＞0.05);以MCS≥4 mm,且MCS＞SCS作为诊断标准时,中立位0°、跖屈位15°、30°、45°时,出现假阳性率分别为50.0％、66.7％、88.9％、94.4％.以MCS≥5 mm,且MCS＞ SCS作为诊断标准时,中立位0°、跖屈位15°、30°、45°时,出现假阳性率分别为5.6％、11.1％、38.9％、77.8％.结论 不同跖屈角度是影响踝三角韧带损伤X线诊断的重要因素,随着踝关节跖屈角度增加,踝三角韧带损伤X线诊断的假阳性率亦随之升高.     

End-stage extension of the knee and its influence on tibial tuberosity-trochlear groove distance (TTTG) in asymptomatic volunteers

Purpose

Increased tibial tuberosity-trochlear groove distance (TTTG) is one potential correcting parameter in patients suffering from lateral patellar instability. It was hypothesized that end-stage extension of the knee might influence the TTTG distance on MR images.

Methods

Transverse T1-weighted MR images of the knee were acquired at full extension, 15° and 30° flexion of the knee in 30 asymptomatic volunteers. MRI parameters: slice thickness: 3 mm, matrix: 256 × 384, FOV: 150 × 150 mm. Two observers independently measured the TTTG at all positions.

Results

Mean TTTG for observer 1 was 15.1 ± 3.2 mm at full extension, 10.0 ± 3.5 mm at 15° flexion and 8.1 ± 3.4 mm at 30° flexion. Mean TTTG for observer 2: 14.8 ± 3.3 mm at full extension, 9.4 ± 3.0 mm at 15° flexion, 8.6 ± 3.4 mm at 30° flexion. Mean values were significantly different (p < 0.001) between full extension and 15° as well as 30° flexion for both observers. Mean values were significantly different (p < 0.001) between 15° and 30° for observer 1, but not for observer 2 (n.s.). Interobserver agreement was very good (intraclass correlation coefficient: 0.87–0.88; p < 0.001).

Conclusions

The TTTG increases significantly at the end-stage extension of the knee. Therefore, the comparability of published TTTG values measured on radiographs, CT and MRI at various flexion/extension angles of the knee are limited.

Level of evidence

Development of diagnostic criteria in a consecutive series of patients and a universally applied ‘gold’ standard, Level II.     

Anatomic double-bundle ACL reconstruction restricts knee extension in knees with hyperextension

Purpose

Double-bundle ACL reconstruction has been demonstrated to be at least as effective as single-bundle reconstruction in terms of restoring knee rotational and translational stability. Until now, the influence on knees with hyperextension has not been evaluated. It was the purpose of this study to evaluate whether double-bundle ACL reconstruction restricts extension in hyperextendable knees.

Methods

Hamstring tendon reconstructions of 10 human cadaveric knees with the ability of hyperextension (age: 48 ± 14 years) were performed as single bundle (SB) on one side and double bundle (DB) on the other side. A surgical navigation system (BrainLab, Germany) was used to assess the kinematics of each knee at the intact and reconstructed state. A difference with regard to the anterior-to-posterior translation (AP) and rotational stability at 30° of knee flexion, 90° of flexion and the hyperextension capability of each specimen was analysed.

Results

The difference in AP translation before and after the reconstruction was not significantly different in 30° and 90° of flexion (n.s). Both single- and double-bundle reconstructions restored the preoperative kinematics at 30° and 90° of knee flexion (n.s). The knee extension was 4° ± 1.8° with the intact ACL and 4° ± 1.7° after reconstruction in the SB group (n.s). The knee extension was 5° of hyperextension ± 1.1° with the intact ACL and 0° ± 0.4° after reconstruction in the DB group; the limitation of the extension was significantly larger in this group (p = 0.013).

Conclusion

Both single- and double-bundle ACL reconstruction techniques are capable of restoring knee anteroposterior and rotational stability. Double-bundle reconstructions significantly reduce knee extension in knees with hyperextension capability. Care must be taken when using double-bundle techniques in patients with knee hyperextension as this procedure may limit the knee extension after double-bundle ACL reconstruction.     

Gait kinematic alterations in subjects with adult spinal deformity and their radiological determinants

BackgroundAdults with spinal deformity (ASD) are known to have postural malalignment affecting their quality of life. Classical evaluation and follow-up are usually based on full-body static radiographs and health related quality of life questionnaires. Despite being an essential daily life activity, formal gait assessment lacks in clinical practice.Research QuestionWhat are the main alterations in gait kinematics of ASD and their radiological determinants?Methods52 ASD and 63 control subjects underwent full-body 3D gait analysis with calculation of joint kinematics and full-body biplanar X-rays with calculation of 3D postural parameters. Kinematics and postural parameters were compared between groups. Determinants of gait alterations among postural radiographic parameters were explored.ResultsASD had increased sagittal vertical axis (SVA:34 ± 59 vs −5 ± 20 mm), pelvic tilt (PT:19 ± 13 vs 11 ± 6°) and frontal Cobb (25 ± 21 vs 4 ± 6°) compared to controls (all p < 0.001). ASD displayed decrease walking speed (0.9 ± 0.3 vs 1.2 ± 0.2 m/s), step length (0.58 ± 0.11 vs 0.64 ± 0.07 m) and increased single support (0.45 ± 0.05 vs 0.42 ± 0.04 s). ASD walked with decreased hip extension in stance (−3 ± 10 vs −7 ± 8°), increased knee flexion at initial contact and in stance (10 ± 11 vs 5 ± 10° and 19 ± 7 vs 16 ± 8° respectively), and decreased knee flexion/extension ROM (55 ± 9 vs 59 ± 7°). ASD had increased trunk flexion (12 ± 12 vs 6 ± 11°) and reduced dynamic lumbar lordosis (−11 ± 12 vs −15 ± 7°, all p < 0.001). Sagittal knee ROM, walking speed and step length were negatively determined by SVA; lack of lumbar lordosis during gait was negatively determined by radiological lumbar lordosis.SignificanceStatic compensations in ASD persist during gait, where they exhibit a flexed attitude at the trunk, hips and knees, reduced hip and knee mobility and loss of dynamic lordosis. ASD walked at a slower pace with increased single and double support times that might contribute to their gait stability. These dynamic discrepancies were strongly related to static sagittal malalignment.     

Isometric fascicle behaviour of the biceps femoris long head muscle during Nordic hamstring exercise variations

ObjectivesTo compare biceps femoris long head (BFlh) muscle tendon unit and fascicle function during Nordic hamstring exercise (NHE) variations with different hip range of motion.DesignCross-sectional.MethodsTwelve healthy volunteers (age: 24 ± 4 years; mass: 77 ± 6 kg; height: 177 ± 4 cm) performed two NHE variations: NHE with hips in neutral (fixed) position (conventional NHE); and NHE with hip flexion/extension. BFlh fascicle length behaviour was assessed using a dual transducer ultrasound configuration. BFlh and semitendinosus muscle electromyography, lower limb kinematics and knee flexion moment were also recorded. A biomechanical model was used to estimate BFlh muscle-tendon unit (MTU) length. Statistical Parametric Mapping was used to assess timing differences in outcome variables across the movement.ResultsIn both variations, during much of the exercise (~30–80% of movement phase), BFlh fascicles undergo little length change (isometric) while the MTU lengthens. Fascicles stretched considerably just in the last ~20% of the exercise, and changes in fascicle length (<2 cm stretch) were smaller in comparison to changes in MTU length (<4 cm stretch). Hip flexion resulted in the muscle tendon unit and fascicles operating at longer lengths until approximately 80% of the movement phase.ConclusionsThe decoupling between fascicle and MTU length seen during the NHE variations suggests that stretch of the elastic tissue of the MTU has an important role in absorbing energy during Nordic hamstring exercises. This may be important when considering adaptations to BFlh muscle and connective tissues that might occur from NHE training.     

Flexion and extension gaps created by the navigation-assisted gap technique show small acceptable mismatches and close mutual correlations

Purpose

The aim of this study was to investigate the mechanism underlying the development of gap differences in total knee arthroplasty using the navigation-assisted gap technique and to assess whether these gap differences have statistical significance.

Methods

Ninety-two patients (105 knees) implanted with cruciate-retaining prostheses using the navigation-assisted gap balancing technique were prospectively analysed. Medial extension and flexion gaps and lateral extension and flexion gaps were measured at full extension and at 90° of flexion. Repeated measures analysis of variance was used to compare the mean values of these four gaps. The correlation coefficient between each pair of gaps was assessed using Pearson’s correlation analysis.

Results

Mean intra-operative medial and lateral extension gaps were 20.6 ± 2.1 and 21.7 ± 2.2 mm, respectively, and mean intra-operative medial and lateral flexion gaps were 21.6 ± 2.7 and 22.1 ± 2.5 mm, respectively. The pairs of gaps differed significantly (P < 0.05 each), except for the difference between the medial flexion and lateral extension gaps (n.s.). All four gaps were significantly correlated with each other, with the highest correlation between the medial and lateral flexion gaps (r = 0.890, P < 0.001) and the lowest between the medial flexion and lateral extension gaps (r = 0.701, P < 0.001).

Conclusion

Medial and lateral flexion and extension gaps created using the navigation-assisted gap technique differed significantly, although the differences between them were <2 mm, and the gaps were closely correlated.

Clinical relevance

These narrow ranges of statistically acceptable gap differences and the strong correlations between gaps should be considered by surgeons, as should the risks of soft tissue over-release or unintentional increases in extension or flexion gap after preparation of the other gap.

Level of evidence

III.     

Alignment in knee flexion position during navigation-assisted total knee arthroplasty

Purpose

The aim of this study was to demonstrate the lower limb alignment in knee flexion position after navigation-assisted total knee arthroplasty using the gap technique and to identify the correlative factors.

Methods

One hundred and twenty consecutive osteoarthritic knees (120 patients) were prospectively enrolled for intraoperative data collection. All TKA surgeries were performed using the navigation system (OrthoPilot?, version 4.0; B. Braun Aesculap, Tuttlingen, Germany). Before and after final prosthesis implantation, the lower limb navigation alignment in both knee extension (0°) and knee flexion (90°) position was recorded. The knee flexion alignment was divided into three groups: varus, neutral and valgus alignment. To determine the factors of the alignment in knee flexion position, preoperative demographics, radiologic and intraoperative data were obtained. Pearson’s correlation (r) analysis was performed to find the correlation. The Knee Society Score and Western Ontario and McMaster Universities Osteoarthritis Index were compared between groups.

Results

Although all postoperative extension alignment was within neutral position (between ?2° and +2°), postoperative knee flexion alignment was divided into three groups: varus (≤?3°), 24 cases (20 %); neutral (between ?2° and +2°), 85 cases (70.8 %) and valgus (≥+3°) alignment, 11 cases (9.2 %). There were a good correlation of alignment in knee flexion position with the rotation of femoral component relative to posterior condylar axis (r = ?0.502, p = 0.000) and weak correlations with posterior femoral cut thickness (lateral condyle) (r = 0.207, p = 0.026), medial flexion (90°) gap after femoral component rotation adjustment (r = 0.276, p = 0.003). Other variables did not show correlations. There were no statistical clinical differences between varus, neutral and valgus knee flexion alignment groups.

Conclusion

About 30 % of the cases showed malalignment of more than 3° in knee flexion position although with neutral alignment in extension position. The knee flexion alignment had a good correlation with the rotation of femoral component relative to posterior condylar axis. Neutral alignment in knee flexion position may be adjusted by femoral component rotation especially by the use of navigation system.

Level of evidence

IV.

     

Neuromuscular adaptations induced by adjacent joint training

Effects of resistance training are well known to be specific to tasks that are involved during training. However, it remains unclear whether neuromuscular adaptations are induced after adjacent joint training. This study examined the effects of hip flexion training on maximal and explosive knee extension strength and neuromuscular performance of the rectus femoris (RF , hip flexor, and knee extensor) compared with the effects of knee extension training. Thirty‐seven untrained young men were randomly assigned to hip flexion training, knee extension training, or a control group. Participants in the training groups completed 4 weeks of isometric hip flexion or knee extension training. Standardized differences in the mean change between the training groups and control group were interpreted as an effect size, and the substantial effect was assumed to be ≥0.20 of the between‐participant standard deviation at baseline. Both types of training resulted in substantial increases in maximal (hip flexion training group: 6.2% ± 10.1%, effect size = 0.25; knee extension training group: 20.8% ± 9.9%, effect size = 1.11) and explosive isometric knee extension torques and muscle thickness of the RF in the proximal and distal regions. Improvements in strength were accompanied by substantial enhancements in voluntary activation, which was determined using the twitch interpolation technique and RF activation. Differences in training effects on explosive torques and neural variables between the two training groups were trivial. Our findings indicate that hip flexion training results in substantial neuromuscular adaptations during knee extensions similar to those induced by knee extension training.