Displacement of the medial meniscus within the passive motion characteristics of the human knee joint: an RSA study in human cadaver knees

The objective of this study was to validate an in vitro human cadaver knee-joint model for the evaluation of the meniscal movement during knee-joint flexion. The question was whether our model showed comparable meniscal displacements to those found in earlier meniscal movement studies in vivo. Furthermore, we determined the influence of tibial torque on the meniscal displacement during knee-joint flexion. Three tantalum beads were inserted in the medial meniscus of six human-cadaver joints. The knee joints were placed and loaded in a loading apparatus, and the movements of the beads were determined by means of RSA during knee-joint flexion and extension with and without internal tibial (IT) and external tibial (ET) torque. During flexion without tibial torque, all menisci moved in posterior and lateral direction. The anterior horn showed significantly greater excursions than the posterior horn in both posterior and lateral direction. Internal tibial torque caused an anterior displacement of the pathway on the tibial plateau. External tibial torque caused a posterior displacement of the pathway. External tibial torque restricted the meniscal displacement during the first 30° of knee-joint flexion. The displacements of the meniscus in this experiment were similar to the displacements described in the in vivo MRI studies. Furthermore, the application of tibial torque confirmed the relative immobility of the posterior horn of the meniscus. During external tibial torque, the posterior displacement of the pathway on the tibial plateau during the first 30° of flexion might be restricted by the attached knee-joint capsule or the femoral condyle. This model revealed representative meniscal displacements during simple knee-joint flexion and also during the outer limits of passive knee-joint motion.     

Repair of meniscal tears with the absorbable Clearfix screw: results after 1–3 years

Introduction Total meniscus resection usually leads to osteoarthritis of the knee joint. Preservation and refixation of the injured menisci are therefore of great clinical importance.Materials and methods The present study examines 40 meniscal injuries in 37 patients that were arthroscopically treated with Clearfix meniscal screws (Mitek, Norderstedt, Germany) in the period from August 1999 to December 2002. The mean patient age was 27.7 (range 16–62) years. Nine patients were female. A total of 24 patients (27 meniscal tears) also had an anterior cruciate ligament (ACL) lesion, and 5 patients had cartilage injuries. Twenty-two patients were treated within the first 2 weeks following the trauma, 10 patients within 8 weeks, and 5 patients after 8 weeks. The lesions were a bucket-handle tear of the medial meniscus in 11 cases and a bucket-handle tear of the lateral meniscus in 2 cases. The posterior horn of the medial meniscus was torn in 13 cases, and the pars intermedia in 3 cases. The posterior horn of the lateral meniscus was torn in 8 cases, and the pars intermedia in 3 cases. The mean tear length was 2.9 (±1.5) cm and was fixed with an average of 1.8 (±0.7) screws. In 7 cases, the anterior horn was treated with an additional meniscal suture. A total of 35 patients were examined after an average of 18 (range 7–45) months.Results In the event of a moderate outcome, MRI was performed as part of the follow-up investigation. The average Lysholm score was 93 (±7.4), the Tegner activity index was 6.3 (±2.0) before the accident and 5.8 (±2.0) at the follow-up, the Marshall knee score was 47 (±3.8). The VAS pain assessment was 1.6 (±1.3) and the VAS function assessment was 7.9 (±1.6). Of the 7 patients with a moderate result, 2 patients without additional ligament lesions suffered re-ruptures after 6 and 13 months, respectively. The other 5 patients with a moderate result each had multiple accompanying injuries or pre-existing damage to the affected knee joint.Conclusion The Clearfix screws achieved a clinical success rate of 82% in isolated meniscal tears in stable knee joints and a clinical success rate of 100% with additional ACL reconstruction. In view of the good clinical results and the simple procedure for use, the implant should be recommended for meniscal refixation.     

Intraspecies and Interspecies Comparison of the Compressive Properties of the Medial Meniscus

Quantification of the compressive material properties of the meniscus is of paramount importance, creating a "gold-standard" reference for future research. The purpose of this study was to determine compressive properties in six animal models (baboon, bovine, canine, human, lapine, and porcine) at six topographical locations. It was hypothesized that topographical variation of the compressive properties would be found in each animal model and that interspecies variations would also be exhibited. To test these hypotheses, creep and recovery indentation experiments were performed on the meniscus using a creep indentation apparatus and analyzed via a finite element optimization method to determine the material properties. Results show significant intraspecies and interspecies variation in the compressive properties among the six topographical locations, with the moduli exhibiting the highest values in the anterior portion. For example, the anterior location of the human meniscus has an aggregate modulus of 160 +/- 40 kPa, whereas the central and posterior portions exhibit aggregate moduli of 100 +/- 30 kPa. Interspecies comparison of the aggregate moduli identifies the lapine anterior location having the highest value (450 +/- 120 kPa) and the human posterior location having the lowest (100 +/- 30 kPa). These baseline values of compressive properties will be of help in future meniscal repair efforts.     

Accuracy of double-contrast arthrography and arthroscopy of the knee joint

Only in the diagnosis of medial meniscal lesions is double contrast arthrography superior to arthroscopy, provided that arthroscopy is carried out only from the anterolateral side (94% against 81% positive correlations). The rates in diagnosing lateral meniscal lesions are respectively 90% and 94.5%, in patellar chondropathy 55% and 99.5% respectively, and in diagnosing cruciate ligament lesions 69% and 97% respectively.     

Computer-assisted design of the sagittal shapes of a ligament-compatible total ankle replacement

The poor results of total ankle replacement have been attributed to the inability of designers to restore adequately the critical mutual function of the ligaments and the articular surfaces. The purpose of this study was to design sagittal shapes of the articular surfaces for a new ankle prosthesis to be compatible with the geometry of the reticular surfaces for a new ankle prosthesis to be compatible with the geometry of the retained ligamentous structures. Several ligament-compatible pairs of articular surfaces were tested using a computerised version of a four-bar linkage model. The kinematics of the ankle when replaced by non-conforming two-component and by fully conforming three-component designs with either flat, concave or convex tibial surfaces were assessed by the model. A ligament-compatible convex-tibia fully-congruent three-component prosthesis showed the best features. The three-component prosthesis allows complete congruence over the entire range of flexion. A convex shape for the tibial are was preferred because of the better degree of entrapment of the meniscal bearing. A 5 cm convex-tibia arc radius gave 2 mm entrapment together with 9.8 mm of tibial bone cut. Ligament elongation imposed by full congruence of the articular surfaces was less than 0.03% of the original length. The original patterns of joint kinematics and ligament tensioning are closely restored in the joint replaced by the proposed prosthesis.     

中药胶剂修复半月板损伤的实验研究

目的 观察中药胶剂促进半月板损伤修复的效果,并探讨其作用机理。方法 选用同样条件饲养,体重３ｋｇ左右的健康成年日本大耳白兔８０只,雌雄不拘,每组４０只,均采用左右侧自身对照,侧别由掷币法随机决定。一组动物为空白对照,即一侧半月板裂伤植入中药胶剂,另一侧裂伤不做任何处理;另一组动物为实验对照,即一侧裂伤植入中药胶剂,另一侧裂伤植入物理性状与该中药胶剂相似的明胶。在日本大耳白兔双侧下肢内侧半月板前１／     

臭氧与曲安奈德治疗膝关节半月板损伤的病例对照研究

目的：比较曲安奈德、臭氧以及两者联合治疗轻型半月板损伤的临床疗效.方法：2008年1月至2012年12月将MRI诊断为Ⅰ、Ⅱ级的半月板损伤患者119例,分为曲安奈德组、臭氧组和曲安奈德加臭氧联合组.曲安奈德组（A组）40例,男38例,女2例;年龄18～48岁,平均（25.34±6.34）岁;单膝36例,双膝4例;关节积液44膝.臭氧组（B组）39例,男37例,女2例;年龄19～50岁,平均（26.98±7.20）岁;单膝33例,双膝6例;关节积液40膝.曲安奈德加臭氧联合组（C组）40例,男37例,女3例;年龄18～47岁,平均（26.44±6.38）岁;单膝33例,双膝7例;关节积液39膝.3组分别以醋酸曲安奈德3 mg、浓度30 μg/ml的医用臭氧30 ml、两者联合行膝关节腔注射,每周1次,4次为1个疗程.治疗前与治疗后的1个月分别进行Lysholm膝关节功能评分和行MRI检查观察膝关节积液变化并比较.结果：3组治疗前后膝关节功能评分分别为A组：35.68±4.15和65.55±7.66;B组：36.35±6.83和74.39±8.47;C组：36.62±6.03和95.47±4.78.3组治疗后膝关节评分均高于治疗前,C组较A、B组评分高,而A、B组间差异无统计学意义.治疗前MRI检查所见关节积液征象的膝数,A组44膝,B组40膝,C组39膝;治疗后MRI检查所见关节积液征象的膝数,A组14膝,B组15膝,C组5膝.C组消除关节积液的效果优于A、B组,A组和B组间差异无统计学意义.结论：臭氧和曲安奈德治疗轻度半月板损伤对缓解症状、促进关节功能恢复、消退关节积液均有效果,两者联用,效果更佳.     

Bilateral bucket handle medial meniscal tears of the knee: A case report

INTRODUCTIONMeniscal tears may cause knee pain and functional impairment. Bilateral bucket-handle meniscal tears is an uncommon condition.PRESENTATION OF CASEThis report presents the case of a 35-year-old male patient with bilateral bucket handle medial meniscal tears that occurred nonsimultaneously. The lesions were treated arthroscopically with partial resection in one knee and meniscal suture in the other.DISCUSSIONBucket handle meniscal tear of meniscus without underlying meniscal, ligamentous pathology or lower limb deformity is a rare condition.CONCLUSIONTo our knowledge, bilateral bucket handle medial meniscal tears without underlying meniscal anomalies have been reported in only two cases before, and our case is the third one.