Arthroscopic irrigation - a cautionary tale

A fit 38-year-old female patient developed absent foot pulses following a routine arthroscopic partial medial meniscectomy. Irrigation fluid, which was delivered using an arthroscopic flushing set, had extravasated through a ruptured Baker's cyst into the popliteal fossa causing vascular compression and spasm. The pulses gradually returned to normal following the procedure. Knee arthroscopy is a common procedure and a Baker's cyst is a common sequel to degenerative disease. With the increasing popularity of pressurised fluid irrigation systems, this previously unreported complication is both relevant and important.     

Personalized volumetric assessment of lower body muscles in patients with knee injuries: A descriptive case series

BackgroundPatients with knee joint pathology present with variable muscular responses across the muscles of the lower limb and pelvis. Conventional approaches to characterizing muscle function are limited to gross strength assessments that may overlook subtle changes both in the thigh, hip and shank musculature.PurposeTo describe individualized patterns of lower extremity muscle volumes in patients with knee pathologies.MethodsThis was a retrospective case series performed in a University medical center. Nine patients diagnosed with meniscus tear recommended to undergo meniscectomy volunteered. Participants underwent 3.0 Tesla magnetic resonance imaging (MRI) of the lower extremities. Thirty-five MRI-derived muscle volumes were compared between limbs and expressed as percentage asymmetry. For additional context, z-scores were also calculated for mass- and height-normalized muscles and pre-determined muscle groupings relative to a normative database.ResultsThere were no consistent patterns observed when considering between-limb asymmetries among all patients. The ankle musculature (dorsiflexors, plantar flexors, and invertors) was the only muscle group to be consistently smaller than normal for all patients, with the psoas major and flexor hallucis longus being the only individual muscles. The severity or chronicity of injury and presence of surgical intervention did not appear to have a clear effect on muscle volumes.ConclusionPatients with a history of meniscal pathology demonstrate inconsistent patterns of lower extremity muscle volumes about the hip, knee, and ankle between limbs and in comparison to uninjured individuals. These data support the need for individualized assessment and intervention in this population.     

胫骨外侧髁骨折塌陷对关节轴线及接触压力的影响

目的:研究在胫骨外侧髁骨折中关节面塌陷和外侧半月板切除对膝关节轴线、接触面积及压力的影响。方法:6个新鲜尸体膝关节标本制成胫骨外侧髁劈裂骨折模型,通过使用支撑垫片制成关节面塌陷0、1、2、4和6mm。膝关节在屈膝0°,负荷500N和屈膝30°,负荷350N。通过数码相机记录关节轴线的变化;而关节内外间隙的压力和压力扩散则由F-Scan感应器记录。每个标本在保留和切除外侧半月板下进行测试。结果:随着关节面塌陷高度的增加,膝关节外翻角度、外侧间隙的平均和最大的接触压力逐渐增加,而接触面积则逐渐减少。在屈膝0°,关节面塌陷6mm时,外翻角度平均增加7.6°,平均接触压力和最大接触压力分别增加208%和97%;而接触面积则减少33%。在同一关节面塌陷高度,切除半月板平均增加38%的外翻角度和外侧间隙45%的接触压力;而接触面积则减少26%。结论:研究结果表明在治疗胫骨外髁劈裂骨折中,减少关节面的塌陷十分重要,特别是在需切除半月板的时候。     

半月板的血供及其临床意义

通过动脉灌注,对56侧儿童和成人尸体的半月板血供进行了研究。成人半月板外1/5为血管区,内4/5为无血管区。半月板的撕裂常发生于无血管区或无血管区与血管区的连接处。半月板的退化和磨损位于无血管区。     

Partial medial meniscectomy leads to altered walking mechanics two years after anterior cruciate ligament reconstruction: Meniscal repair does not

BackgroundPartial meniscectomy dramatically increases the risk for post-traumatic, tibiofemoral osteoarthritis after anterior cruciate ligament reconstruction (ACLR). Concomitant medial meniscus surgery influences walking biomechanics (e.g., medial tibiofemoral joint loading) early after ACLR; whether medial meniscus surgery continues to influence walking biomechanics two years after ACLR is unknown.Research questionDoes medial meniscus treatment at the time of ACLR influence walking biomechanics two years after surgery?MethodsThis is a secondary analysis of prospectively collected data from a clinical trial (NCT01773317). Fifty-six athletes (age 24 ± 8 years) with operative reports, two-year biomechanical analyses, and no second injury prior to two-year testing participated after primary ACLR. Participants were classified by concomitant medial meniscal status: no medial meniscus involvement (n = 36), partial medial meniscectomy (n = 9), and medial meniscus repair (n = 11). Participants underwent biomechanical analyses during over-ground walking including surface electromyography; a validated musculoskeletal model estimated medial compartment tibiofemoral contact forces. Gait variables were analyzed using 3 × 2 ANOVAs with group (medial meniscus treatment) and limb (involved versus uninvolved) comparisons.ResultsThere was a main effect of group (p = .039) for peak knee flexion angle (PKFA). Participants after partial medial meniscectomy walked with clinically meaningfully smaller PKFAs in both the involved and uninvolved limbs compared to the no medial meniscus involvement group (group mean difference [95%CI]; involved: −4.9°[−8.7°, −1.0°], p = .015; uninvolved: −3.9°[−7.6°, −0.3°], p = .035) and medial meniscus repair group (involved: −5.2°[−9.9°, −0.6°], p = .029; uninvolved: −4.7°[−9.0°, −0.3°], p = .038). The partial medial meniscectomy group walked with higher involved versus uninvolved limb medial tibiofemoral contact forces (0.45 body weights, 95% CI: −0.01, 0.91 BW, p = 0.053) and truncated sagittal plane knee excursions, which were not present in the other two groups.SignificanceAberrant gait biomechanics may concentrate high forces in the antero-medial tibiofemoral cartilage among patients two years after ACLR plus partial medial meniscectomy, perhaps explaining the higher osteoarthritis rates and offering an opportunity for targeted interventions.Level of EvidenceLevel III.     

Effects of radial tears and partial meniscectomy of lateral meniscus on the knee joint mechanics during the stance phase of the gait cycle—A 3D finite element study

The purpose of the current study was to evaluate influences of radial tears and partial meniscectomy of lateral meniscus on the knee joint mechanics during normal walking by using computational modeling. A 3D geometry of a knee joint of a healthy patient was obtained from our previous study, whereas the data of normal walking were taken from the literature. Cartilage tissue was modeled as a fibril reinforced poroviscoelastic material, whereas meniscal tissue was modeled as a transverse isotropic elastic material. The realistic gait cycle data were implemented into the computational model and the effects of radial tears and partial meniscectemy of lateral meniscus on the knee joint mechanics were simulated. Middle, posterior, and anterior radial tears in lateral meniscus increased stresses by 300%, 430%, and 1530%, respectively, at the ends of tears compared to corresponding areas in the model with intact lateral meniscus. Meniscus tears did not alter stresses and strains at the tibial cartilage surface, whereas partial meniscectomy increased contact pressures, stresses, strains and pore pressures in the tibial cartilage by 50%, 44%, 21%, and 43%, respectively. Increased stresses and strains were observed primarily during the first ～50% of the stance phase of the gait cycle. The present study suggests that anterior radial tear causes the highest risk for the development of total meniscal rupture, whereas partial meniscectomy increases the risk for the development of OA in lateral tibial cartilage. Highest risks for meniscus and cartilage failures are suggested to occur during the loading response and mid‐stance of the gait cycle. In the future, the present modeling may be further developed to offer a clinical tool for aid in decision making of clinical interventions for patients with knee joint injuries. © 2013 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 31:1208–1217, 2013     

外侧半月板切除术后膝关节周围骨密度的变化及其影响因素

目的: 观察外侧半月板切除术后膝关节周围骨密度的变化及其影响因素. 方法: 选择术后患者128例,根据术后时间分为: 0～1 a组, 2～4 a组,5～10 a组和11～17 a组, 对照组为对应健侧;根据性别、手术时年龄和体质量各设: 男性组,女性组;≤40岁组,＞40岁组;≤75 kg组,＞75 kg组;应用双能X线骨密度仪测量膝关节周围6个目的区(ROI)骨密度,并进行性别、年龄和体质量与骨密度的线性相关分析. 结果: 0～1 a组6区骨密度下降, R1～R4下降显著分别为0.93±0.30, 0.91±0.21, 1.25±0.36和1.30±0.51 (P＜0.01);2～4 a组R1～R4骨密度下降,而R5, R6骨密度增加,其中以R1, R3变化显著,分别为0.93±0.22和1.28±0.08 (P＜0.01);术后5～10 a组除R2骨密度下降外,其余骨密度增加,以外侧ROI骨密度增加显著,分别为0.95±0.12,1.20±0.19及1.25±0.18 (P＜0.05);术后11～17 a组R1, R3骨密度下降分别为: 0.93±0.20, 1.19±0.18,与对照组比较差异有显著的统计学意义(P＜0.05). 结论: 外侧半月板切除术后膝关节周围发生适应性骨重构是多种因素作用的结果.     

内侧副韧带切断合并半月板部分切除对大鼠膝关节软骨、滑膜和细胞因子的影响

目的:观察内侧副韧带切断合并半月板部分切除对大鼠膝关节软骨、滑膜和关节液中细胞因子的影响。方法:20只SD大鼠,行内侧副韧带切断和内侧半月板部分切除术,分别在术后第1、2、3、4和5周各处死4只大鼠并取材;另备4只作为正常对照。组织学观察其关节软骨和滑膜的变化,酶联免疫吸附法(ELISA)测定关节液中细胞因子白细胞介素-1β(IL-1β)和肿瘤坏死因子-α(TNF-α)表达。结果:膝关节内侧副韧带切断和部分半月板切除后,大鼠关节液中IL-1β和TNF-α表达显著增高,TNF-α在术后第1周时、IL-1β在术后第2周时达到峰值,然后逐渐下降,第5周时仍显著高于正常对照水平。术后第1周,关节软骨丢失,软骨层变薄;软骨细胞减少,排列层次紊乱,有簇聚现象;蛋白多糖分泌减少,表面的软骨组织甲苯胺蓝染色失染。第2周,软骨继续退变,表面软骨纤维化,软骨下骨硬化,部分侵入软骨层,蛋白多糖进一步丢失,甲苯胺蓝染色失染严重。从第3周开始,正常的软骨细胞基本消失,呈纤维样变,软骨下骨硬化;髓腔融合、开放、纤维化,呈现晚期骨性关节炎的改变。滑膜细胞从术后第1周开始增生,炎细胞浸润;第2周滑膜炎症加重,并有血管增生;第3周滑膜已出现明显的纤维化改变。结论:内侧副韧带切断伴内侧半月板部分切除后,大鼠膝关节呈现骨性关节炎的改变,关节液中IL-1β和TNF-α表达显著增高。     

关节镜下清理并半月板切除治疗合并膝骨关节炎的半月板损伤

目的探讨关节镜下清理并半月板切除治疗合并早、中期膝关节骨关节炎(KOA)的中、重度半月板损伤的疗效。方法选取2011年10月-2014年10月该科156例合并有早、中期KOA的中、重度半月板损伤患者,行关节镜下清理并半月板切除术。术前对所有患者行Lysholm膝关节功能评分,常规行膝关节正侧位、髌骨轴位、双下肢全长站立位X片和患膝磁共振成像(MRI)检查,明确KOA诊断和临床分期以及半月板损伤诊断和分级。所有患者均在全麻下行关节镜下关节清理并半月板切除术。术后积极行患肢康复训练,术后7~10天出院,出院后佩戴护膝负重行走。采用门诊复诊或电话方式对患者进行随访。结果所有患者均无围手术感染、化脓性关节炎等严重围手术期并发症;术后随访6~12个月,平均10.9个月。Lysholm膝关节功能评分术后(87.3±7.9)明显优于术前(67.5±4.9)(P0.05)。结论关节镜下清理并半月板切除治疗合并早、中期KOA的中、重度半月板损伤,创伤小、恢复快、近期疗效良好。     

Knee joint biomechanics following arthroscopic partial meniscectomy

We investigated spatiotemporal data, joint kinematics, and joint kinetics during gait in a group of subjects who had recently undergone arthroscopic partial meniscectomy and compared the results to those of healthy controls. Gait analysis was performed on 105 pain‐free meniscectomy patients and 47 controls, walking at a self‐selected speed. The meniscectomy population was comparable to controls in spatiotemporal parameters and knee kinematics. However, they had reduced range of motion (ROM) and lower peak moments in the sagittal plane on the operated limb compared to the nonoperated limb. Compared to controls, the meniscectomy patients had significantly larger knee adduction moments over stance, even after accounting for their greater body weight. These differences likely increase articular loads on the medial compartment of the tibiofemoral joint and may contribute to the high risk of knee osteoarthritis following arthroscopic meniscal surgery. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:1075–1080, 2008