CR-lipped bearing is an adequate functional solution to patients with perioperative excessive laxity in cruciate retaining total knee arthroplasty

BackgroundThe cruciate retaining lipped (CR-lipped) bearing is designed to provide more anterior-posterior (AP) stability and could be employed to resolve excessive intraoperative laxity during the cruciate retaining TKA (CR-TKA). The aim of the study was to determine whether the CR-lipped bearing in CR-TKAs with a perioperative excessive laxity allows equivalent functional results as compared to the standard CR articulation.MethodsA cohort of 111 TKAs with CR-lipped bearings was matched to a cohort of conventional CR bearings regarding age and sex. The CR-lipped bearing was used in patients with excessive knee AP laxity and the regular CR bearing was used in patients without excessive AP laxity during TKA. Various PROMs (WOMAC, KSS, SF-36) were assessed preoperatively and at 5-years postoperative in combination with revision rate and Range of Motion (ROM).ResultsPROMs did not differ significantly between both groups 5-years postoperatively. Mean ROM (flexion) 5-years postoperatively was not significantly different. The implant survivorship was 100% for both cohorts with revision for any reason as end point.ConclusionBased on these results, the CR-lipped bearing is a safe and effective solution for mild interoperatively assessed PCL laxity during CR-TKA without loss of function or decreased survivorship at 5 years. Peroperative conversion to a PS-TKA in order to obtain satisfactory functional scores might therefore not be necessary when mild PCL laxity is observed during surgery. Further research should focus on verifying this approach and longer follow-up is needed to generate data on long term survivorship.Level of evidenceLevel IV therapeutic, retrospective, cohort study.     

基于膝关节三维模型的髌股关节动力学特性研究

目的构建有效的膝关节三维模型以计算髌股关节动力学参数。方法基于CT图像处理和CAD技术, 重建包括股骨下端、胫骨上端及髌骨的膝关节的骨骼三维模型,并定义髌股关节运动起重要作用的股四头肌直线模型、韧带及其它软组织的非线性弹性纤维束模型,以股四头肌肉力为输入控制变量。结果构造出一个有效的膝关节三维模型。结论该模型可以有效的计算髌股关节动力学参数。     

Osteotomy around the knee: Assessment of quality,content and readability of online information

BackgroundAs knee osteotomy surgery becomes increasingly accessible, more patients may turn to the Internet for information. This study examined the source, quality, content and readability of online information regarding osteotomy around the knee.MethodsThe first 70 websites returned by the top four search engines were identified using the key words: “knee osteotomy” and “high tibial osteotomy.” The websites were categorised by type and assessed using the DISCERN score, Journal of the American Medical Association (JAMA) benchmark criteria and a novel Knee Osteotomy-Specific Score (KOSS). The presence of the Health On the Net (HON) code accreditation seal was noted. Readability of each website was assessed using eight readability formulae. The mean reading grade level (RGL) was compared to the 6th and 8th grade reading levels. The mean RGL of each category was also compared.ResultsOf the 45 unique websites analysed, the majority were Physician (33%) and Journal websites (31%). The mean DISCERN score was 36.7 (±8.9) which is classified as ‘poor.’ The mean JAMA benchmark criteria score was 2.04 (±1.5) and Physician websites were most likely to be scored zero. The mean KOSS was 15.4 (±5.7). The highest scoring website was a Commercial site but, overall, Journal category sites provided the best quality information. Websites that bore the HONcode seal obtained higher DISCERN, JAMA benchmark criteria and Knee Osteotomy - Specific Scores.The cumulative mean RGL was 13.2 (±2.2) which exceeded the 6th grade level by an average of 7.2 grade levels and the 8th grade level by an average of 5.2 grade levels. No website (0%) was written at or below either the 6th or the 8th grade reading levels. The mean Flesch Reading Ease Score of all websites was 41.13 (±14.7) which is classified as ‘difficult.’ Journal websites had the highest RGL.ConclusionThe information available online regarding osteotomy around the knee varies tremendously in quality and completeness. Physician sites predominate, but these were among the lowest scoring of all websites. Even where high quality information is available, it is set at too high a level to be easily understood.Level of evidenceSurvey of materials – Internet.     

Intra-articular morphine and postoperative analgesia after knee arthroscopy

The aim of this study was to evaluate the postoperative analgesic effect of intra-articular administration of a low- and a high-dose morphine solution after knee arthroscopy. Thirty patients who underwent diagnostic arthroscopy or arthroscopic meniscectomy were allocated in three groups. At the end of the arthroscopic procedure patients in Group A received intra-articularly 20 ml normal saline (N/S), Group B received 5 mg morphine in 20 ml N/S and Group C received 15 mg morphine in 20 ml N/S. The postoperative pain was assessed using a visual analogue scale for 24 h, while all the patients stayed at hospital. Side effects from the central action of opioids were not detected. Although the pain scores in the group of low-dose morphine were lower than in the control group, we failed to detect any significant differences in pain scores among the three groups. There was evidence that a high-dose can cause hyperalgesia.     

膝关节动脉的血液供应

本文通过动脉灌注,对120侧不同年龄(新生儿至87岁)尸体的膝关节骨性部和软组织的血液供应分别进行了研究。新生儿的膝动脉在软骨内分布呈节段性,软骨骨化后,骨骺和髌骨的动脉间建立广泛的吻合。骺软骨板分隔膝关节的骨骺与干骺端。随骺板的闭合,两者间有血管互相交通。骺板的血液供应来自骺动脉、干骺动脉和滋养动脉终末的毛细血管袢以及骨膜动脉网的小支。髌骨的动脉分3组,发自髌前丛和髌周动脉环。滑膜和髌下脂垫的血管分布丰富。肌睫和韧带在骨的附着处缺乏血管。成人半月板外1/5有血管分布,内4/5无血管。本文对膝关节血管分布的临床意义作了简要讨论。     

MR imaging of posteromedial and posterolateral stabilisers of the knee: anatomic basis and patterns of lesions in knee injuries

Summary The angular points are the ligamentous and tendinous structures that reinforce the posteromedial and posterolateral capsule of the knee and share in fixation of the posterior horns of the menisci. They are often damaged in acute injuries and this is usually associated with ruptures of the cruciate and collateral ligaments and may add to the degree of laxity. We describe the normal appearance of these structures in terms of the sectional anatomy, correlated with the lesional appearances of complete and incomplete ruptures and associated meniscal detachments as shown by clinical testing and arthrotomy findings.

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IRM des points d'angle du genou : bases anatomiques et applications aux genoux traumatiques

Résumé Les points d'angle sont des structures ligamentaires et tendineuses qui renforcent la capsule postéro-médiale et postéro-latérale et participent à la fixation des cornes postérieures des ménisques. Leurs lésions, fréquentes au cours des traumatismes aigus, sont généralement associées à des ruptures des ligaments croisés et des ligaments collatéraux et peuvent être source d'une aggravation de la laxité. Nous rapportons, en corrélation avec l'anatomie en coupe, l'aspect normal de ces structures, et en corrélation avec les données de l'arthrotomie et du testing les aspects lésionnels observés au cours des traumatismes : ruptures complètes, incomplètes et désinsertions méniscales associées.

     

膝关节动脉血液供应的初步观察

本文选择固定和新鲜尸体下肢标本57侧,采用局部解剖、动脉铸型、动脉造影和标本透明等方法,对膝关节动脉血液供应作了初步观察。动脉关节支起点变异和共干形式,以右侧居多。膝区各动脉均有特殊的形态和一定的分布区域,在每一局部几个血液供应来源中,总有一个主次关系和层次关系。膝区动脉按口径大小,可以分成3组。口径的变化除了可以评价局部血液供应丰富的程度外,也是衡量相邻动脉大小的指征。整个膝区动脉血液供应配布比较均匀对称。供应膝关节的各动脉起点的高度是恒定的,相互间保持一定关系。本文还就纯关节支和肌关节支的概念、动脉吻合、局部“乏血管区”、髌前动脉网与髌骨血液供应的关系等进行了简单讨论。     

Antagonist moment of force during maximal knee extension in pubertal boys: effects of quadriceps fatigue

The examination of the moment exerted by the hamstrings during maximum isokinetic knee extensor tests is useful when comparing isokinetic strength and muscle activity patterns between children and adults. The purpose of this study was to examine the effect of antagonist moment of the hamstrings on the isokinetic moment of the knee extensors in pubertal children and to determine whether this effect is altered following a fatigue task. Eighteen healthy pubertal males [age 14.3 (0.5) years] performed 34 maximal isokinetic concentric efforts of the knee extensors at 60°·s⁻¹. The average moment of force and electromyographic (aEMG) signal of vastus medialis (VM), vastus lateralis (VL) and biceps femoris (BF) at 11–30°, 31–50°, 51–70° and 71–90° of knee flexion were calculated for each repetition. The hamstrings antagonist moment was determined before and after the fatigue task by fitting the aEMG–moment relationship at different levels of muscle effort using second-degree polynomials. The percentage contribution of the antagonist moment to the resultant joint moment ranged from 7.1 % to 60.4 % throughout the range of motion, with the highest percentage observed close to full knee extension (11–30°). The antagonist effect was significantly greater during concentric tests of the knee extensors compared to the corresponding eccentric tests (p<0.05). Following the fatigue test, there was an overall decline of the resultant joint moment, but no changes in the predicted hamstrings moment were observed. These results indicate that when testing maximal knee extensor isokinetic strength in pubertal boys, activity of the hamstrings implies a reduction of the net extensor moment as compared to the isolated capacity of the knee extensors. However, this antagonist effect is not altered following the performance of an isokinetic fatigue knee extension task. Electronic Publication     

Contraction history affects the in vivo quadriceps torque-velocity relationship in humans

We hypothesized that the history of contraction would affect the in vivo quadriceps torque-velocity relationship. We examined the quadriceps torque-velocity relationship of the human knee extensors at the descending and ascending limb of the torque-position relationship by initiating the knee extension at a knee angle position of 1.39 rad (80°) or 0.87 rad (50°) over a 0.52 rad (30°) range of motion under conditions of constant or linearly increasing velocity. Maximal voluntary isometric knee extension torque (M₀) was measured at 1.87 rad, 0.87 rad, and 0.35 rad, and concentric torque was measured. The subjects carried out ten maximal knee extensions at ten distinct velocities, each velocity ranging between 0.52 rad·s^–1 to 5.24 rad·s^–1 in steps of 0.52 rad·s^–1. Peak concentric torque was measured and mean torque calculated from the respective torque-time curves. Peak or mean torque, computed from the individual torque-time curves, and velocity data were fitted to the Hill equation under the four experimental conditions and the curve parameters computed. The M₀ was similar at 0.87 rad and 1.39 rad, but it was significantly lower at 0.35 rad. In the low-velocity domain of the torque-velocity curve where a plateau normally occurs, peak torque was always lower than M₀. Peak and mean torque were significantly greater under linearly increasing velocity conditions and the 1.39 rad starting knee position. Mean torque but not peak torque data could be well fitted to the Hill equation and the two computations resulted in significantly different Hill curve parameters including the concavity ratio, peak power, and maximal angular velocity. We concluded that the history of contraction significantly modifies the in vivo torque-velocity relationship of the human quadriceps muscle. Muscle mechanics and not neural factors may have accounted for the inconsistencies in the human torque-velocity relationships reported previously. Electronic Publication     

Arterial and lymphatic supply of the knee integuments

Summary The surgical approach to the anterior knee region carries a risk for postoperative integument infection and skin necrosis. A hypothesis is that surgical approach may damage integumental blood supply and additionally the lymphatic drainage from the foot and leg. The goal of this study was to describe the arteries and lymphatics directly affected by the antero-medial approach. Injection of the femoral a. was used to identify the femoral and popliteal aa. and their branches distributed to the integument of the anterior, medial and lateral aspects of the knee. Lymphatic injection into the plantar aspect of the first toe was also performed to identify the subdermal lymphatics traversing the area. Our results showed that most of the blood supply arises from the medial aspect of the knee integuments. However, subcutaneous arterial anastomoses provide a significant blood-supply when there is interruption of the medial vessels as seen in the medial surgical approach to the knee. Most of the lymphatic drainage originating from the foot crosses the knee region on the medial side, opposite or below the tibial tuberosity. Because the subdermal arterial network is well-developed, the medial approach for knee surgery does not endanger the anterior knee integuments as long as the lateral vascular supply is preserved. However, this approach may interrupt the lymphatic circulation, particularly in the case of an extended incision, which could explain postoperative edema and an increased rate of wound infection.

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Vascularisation artérielle et lymphatique des téguments du genou

Résumé L'abord chirurgical du genou présente un risque d'infection post-opératoire et de nécrose cutanée. Une hypothèse serait que la voie d'abord peut détruire la vascularisation artérielle et lymphatique qui draine la jambe et le pied. Le but de notre étude était de décrire la circulation artérielle et lymphatique impliquée dans la voie d'abord antéromédiale du genou. Des injections ont été utilisées pour identifier les aa. fémorale et poplitée et leurs branches qui se distribuent aux téguments de la région médiale et latérale du genou. Des injections lymphatiques ont été également utilisées pour localiser le réseau subdermique lymphatique de la région du genou. Nos résultats montrent que la majorité de l'apport artériel des téguments du genou provient de la partie médiale. Des anastomoses sub-cutanées entre les systèmes artériels latéral et médial permettent un apport artériel suffisant pour les téguments en cas d'interruption de l'apport médial. La plupart des vaisseaux lymphatiques provenant du pied et de la cheville croisent la région dorsale du pied de dehors en dedans à une distance variable de la tubérosité tibiale. Du fait du bon développement du réseau artériel sub-cutané, la voie d'abord médiale ne présente pas de risque de nécrose des téguments de la face antérieure du genou tant que l'apport latéral est préservé. Toutefois, elle peut être responsable de l'interruption des conduits lymphatiques, en particulier lorsque l'incision s'étend vers le bas, exposant aux lésions des collecteurs lymphatiques, ce qui expliquerait un dème post-opératoire et un taux accru d'infection.