Articular cartilage thickness and glycosaminoglycan distribution in the young canine knee joint after remobilization of the immobilized limb

The recovery of articular cartilage from atrophy induced by joint immobilization was investigated in immature dogs. In a previous study, we showed that 11 weeks of immobilization of the knee (stifle) joint of young dogs reduced the concentration of articular cartilage glycosaminoglycans (GAGs) by 13–47%. In the present study, right hindlimbs from six female beagles were immobilized for 11 weeks, as in the previous study, and then were remobilized for 15 weeks. Cartilage from the knee joint was compared with cartilage from nonimmobilized knees of eight age-matched control beagles. Histological samples taken from 11 different locations of the knee joint were stained with safranin O, and microspectrophotometry was used to demonstrate distribution of GAGs in the tissue. After remobilization, GAG concentration was restored in the patellofemoral region and tibial condyles. On the summits of the femoral condyles, and especially at the periphery of the femoral condyles, GAG concentration remained 8–26% less than the control values. On the summits, the thickness of the uncalcified cartilage was as much as 15% less than in the age-matched controls. Consequently, the changes induced by unloading were reversible to a great extent, but a full restoration of articular cartilage was not obtained at all sites of the knee joint within the 15 weeks of remobilization. Immobilization of the skeletally immature joint therefore may affect the development of articular cartilage in such a way that very slow recovery or permanent alterations are induced.     

膝关节软骨人体标本解剖与磁共振成像的比较研究

目的 探讨膝关节尸体标本解剖与磁共振成像(MRI)三维序列-扰相梯度回波序列(3D-FS-SPGR)测量关节软骨厚度的差异,并分析软骨组织主要成分在关节软骨不同位置的差异.方法选用国人青壮年中等身材、无明显关节病变的成年男性尸体膝关节标本2具,首先进行3D-FS-SPGR序列矢状位扫描.复冻后按解剖部位进行矢状位解剖,分别对股骨及胫骨内、外髁负重区前、后面及髌骨面软骨厚度进行测量.关节软骨石蜡切片进行维多利亚蓝-丽春红复合染色并观察.结果 软骨尸体标本解剖与3D-FS-SPGR序列测得的膝关节软骨厚度:股骨外侧髁前负重面平均分别为2.25、2.25 mm,股骨外侧髁后负重面平均分别为2.70、2.75 mm,胫骨外侧髁前负重面平均分别为2.00、2.10 mm;胫骨外侧髁后负重而平均分别为2.35、2.25 mm,股骨内侧髁前负重面平均分别为2.20、2.20 mm,股骨内侧髁后负重面平均分别为2.15、2.30 mm,胫骨内侧髁前负重面半均分别为2.20、2.45mm,胫骨内侧髁后负重面平均分别为2.70、2.95 mm,髌骨面软骨平均分别为3.08、3.15 mm.软骨组织学染色显示:关节软骨表层胶原纤维含量相对较多,软骨细胞及其周围基质相对较少;在关节软骨深层,胶原纤维含量相对较少,而软骨及软骨周围基质相对较多.结论 3D-FS-SPGR序列能够相对真实地反映关节软骨的形态及厚度.胶原纤维主要集中在软骨表层,其分布与软骨的功能相一致.     

膝关节软骨人体标本解剖与磁共振成像的比较研究

目的 探讨膝关节尸体标本解剖与磁共振成像(MRI)三维序列-扰相梯度回波序列(3D-FS-SPGR)测量关节软骨厚度的差异,并分析软骨组织主要成分在关节软骨不同位置的差异.方法选用国人青壮年中等身材、无明显关节病变的成年男性尸体膝关节标本2具,首先进行3D-FS-SPGR序列矢状位扫描.复冻后按解剖部位进行矢状位解剖,分别对股骨及胫骨内、外髁负重区前、后面及髌骨面软骨厚度进行测量.关节软骨石蜡切片进行维多利亚蓝-丽春红复合染色并观察.结果 软骨尸体标本解剖与3D-FS-SPGR序列测得的膝关节软骨厚度:股骨外侧髁前负重面平均分别为2.25、2.25 mm,股骨外侧髁后负重面平均分别为2.70、2.75 mm,胫骨外侧髁前负重面平均分别为2.00、2.10 mm;胫骨外侧髁后负重而平均分别为2.35、2.25 mm,股骨内侧髁前负重面平均分别为2.20、2.20 mm,股骨内侧髁后负重面平均分别为2.15、2.30 mm,胫骨内侧髁前负重面半均分别为2.20、2.45mm,胫骨内侧髁后负重面平均分别为2.70、2.95 mm,髌骨面软骨平均分别为3.08、3.15 mm.软骨组织学染色显示:关节软骨表层胶原纤维含量相对较多,软骨细胞及其周围基质相对较少;在关节软骨深层,胶原纤维含量相对较少,而软骨及软骨周围基质相对较多.结论 3D-FS-SPGR序列能够相对真实地反映关节软骨的形态及厚度.胶原纤维主要集中在软骨表层,其分布与软骨的功能相一致.

Abstract：

Objective To compare corpse sampling and MR imaging with 3D-FS-SPGR sequences in measurement of the articular cartilage thickness and to investigate knee cartilage topography. Methods Two fresh specimens of the knee joint were obtained from 2 normal young adult male corpses of medium stature. MR1 scanning was carried on the 2 specimens in sagittal 3D-FS-SPGR MR sequences. After defrosted,the knee specimens were dissected longitudinally, and the cartilage thicknesses were measured at different locations of the knee joint. Paraffin sections of the knee cartilage were observed following compound staining with victoria blue and ponceau red. Results The average cartilage thicknesses measured by dissection and MR imaging sequence were respectively: 2. 25 mm and 2. 25 mm at the anterior weight-loading surface of the femoral lateral condyle, 2. 70 mm and 2. 75 mm at the posterior weight-loading surface of the femoral lateral condyle, 2. 00 mm and 2. 10 mm at the anterior weight-loading surface of the tibial lateral condyle,2. 35 mm and 2. 25 mm at the posterior weight-loading surface of the tibial lateral condyle, 2. 20 mm and 2. 20mm at the anterior weight-loading surface of the femoral medial condyle, 2. 15 mm and 2. 30 mm al the posterior weight-loading surface of the femoral medial condyle, 2. 20 mm and 2.45 mm at the anterior weight-loading surface of the tibial medial condyle, 2. 70 mm and 2. 95 mm at the posterior weight-loading surface of the tibial medial condyle and 3. 08 mm and 3. 15 mm at patella cartilage surface. Collagen fibers were rich at the periphery of the articular cartilage with sparse chondrocytes and matrixes, while the opposite was observed at the center of the articular cartilage. Conclusions MR imaging with 3D-FS-SPGR sequences can display the actual knee cartilage topography. Collagen fibers mainly concentrate at the periphery of the articular cartilage, which accounts for the function of the articular cartilage.     

大运动量跑步对大鼠膝关节软骨蛋白多糖的影响

目的 观察平板跑步运动对大鼠关节软骨蛋白多糖的影响.方法 将Wistar大鼠10只随机分为对照组和跑步组.对照组笼养,跑步组每天以20m/min速度,连续跑步1000m,每天1次.连续训练45d后,处死大鼠,切取双膝关节,固定,脱钙,包埋,沿矢状面整体切片,苏木素-伊红(HE)及番红O染色.观察股骨内侧髁负重区和胫骨内侧平台负重区软骨形态结构和基质染色差异,利用图像分析系统,测量胫骨平台软骨厚度,并对软骨各层染色深浅进行吸光度定量.结果 对照组软骨结构正常,跑步组软骨表面完整,胫骨内侧平台负重区非钙化层厚度较对照组显著下降(P<0.05);番红O染色,负重区软骨非钙化层平均吸光度较对照组明显下降(P<0.05),其中表层下降66%(P<0.01),中层下降56%(P<0.01),深层与对照组差异无统计学意义(P>0.05),而钙化层吸光度较对照组上升38%(P<0.05).结论 大鼠连续平板运动45d后,膝关节负重区软骨虽然结构完整,但已经出现退行性改变.

Abstract：

Objective To study the influences of the strenuous running training program on the knee joint articular cartilage. Methods At the age of 16 weeks, 5 male Wistar rats started running on a horizontal treadmill. Thereafter, the rats were trained for 45 days continuously. The rats ran 1 km/day at the speed of 20 m/min. Five matched male rats served as controls. Knees of the rats were studied by whole-mounted section, Hematoxylin and Eosin (HE) stain, safranin O stain. Results The cartilage surfaces were intact after the running exercise. The glycosaminoglycan concentration was decreased by an average of 66% in the superficial zone, 56% on the middle zone, but no difference was found in the deep zone. The glycosaminoglycan concentration was increased by 38% in the calcified cartilage. Conclusion Strenuous running induced marked decrease of proteoglycan in the uncalcified cartilage, but induced no osteoarthritis in this rat strenuous running model.     

Clinical significance of knee joint changes after meniscectomy

The incidence of Fairbank's radiologic knee joint changes after unilateral meniscectomy was investigated in 180 patients. All patients who had a fracture, cartilage disorders, and/or ligamentous instability at the time of operation or suffered from identical lesions during the follow-up period were excluded. The degree of Fairbank's changes, squaring and sclerosis of the tibial and femoral chondylar articular surfaces, was compared with the postoperative results. The assessment of the results was based on the patient's history. An unsatisfactory postoperative result appeared to coincide more often with Fairbank's changes, but no relation could be demonstrated between the degree of Fairbank's changes and the postoperative result. Fairbank's changes were observed in 77 (42.8%) of the patients. No relation could be demonstrated between the length of the follow-up period and the degree of Fairbank's changes.     

Articular cartilage changes following meniscal lesions. Repair and meniscectomy studied in the rabbit knee

A well-defined, longitudinal lesion in the avascular part of the medial meniscus of the right knee was made in 30 rabbits. After 3 months, the lesion was repaired surgically in 12 rabbits, was untreated in 12 rabbits, and a meniscectomy was performed in 6 rabbits. The articular cartilage was studied macroscopically and microscopically at 3-month intervals. Cartilage changes 3 months after meniscectomy were more pronounced than after meniscal repair or than in untreated lesions. However, meniscal repair did not reverse the cartilage changes.     

Articular cartilage after meniscectomy: Rabbit knees studied with the scanning electron microscope

Ten rabbits had a medial meniscectomy in both knees. The articular surface was studied with a scanning electron microscope 2, 4 or 12 weeks after the operation. Three sham operated and two unoperated rabbits served as controls.

Progressive articular cartilage damage was observed on the weight-bearing areas of the medial condyles. The findings are compatible with clinical observations after meniscectomy; they confirm that meniscectomy is not a harmless operation.     

Articular cartilage lesions of the knee

The pathogenesis and clinical significance of articular cartilage lesions of the knee persist as topics of considerable interest among orthopedic surgeons. This study was designed to assess the association of articular cartilage degeneration with concomitant intraarticular abnormalities and to correlate the prevalence and severity of articular cartilage damage with preoperative historical and physical exam findings in patients presenting with knee pain. Twenty-six history and physical exam data points were prospectively collected from 192 patients (200 knees), consecutively undergoing arthroscopic knee surgery. During surgery, all articular cartilage lesions were recorded with respect to size, location, and character and were graded according to Oglivie-Harris et al. All concomitant knee joint abnormalities were simultaneously recorded. Of 200 knees examined arthroscopically, 12 knees revealed no demonstrable etiology for the presenting symptoms, 65 knees revealed assorted intraarticular pathology but no articular cartilage degeneration, and the remaining 123 knees revealed a total of 211 articular cartilage lesions (103 femoral, 72 patellar, 36 tibial); 7 femoral, 6 patellar and 0 tibial lesions were completely isolated (no concomitant knee joint pathology). The concomitance of femoral defects with tibial lesions was highly significant (p = 0.01). Femoral and tibial articular cartilage lesions were strikingly correlated with the presence of an unstable torn meniscus (p less than 0.001). Medial compartment articular cartilage lesions were significantly more common (p = 0.001), more closely associated with meniscal derangement, and appreciably more severe than lateral compartment lesions. In 75% of anterior cruciate ligament-deficient knees with concomitant articular cartilage degeneration, the duration from injury to surgery was greater than 9 months, and in each of these cases, a history of reinjury to the knee was elicited. From these data one can conclude that: (a) in some patients with painful knees, isolated articular cartilage lesions may be the only abnormality noted at arthroscopy; (b) unstable meniscal tears are significantly associated with destruction of articular cartilage; (c) the medial compartment is particularly susceptible to articular cartilage degeneration; and (d) in our series, anterior cruciate ligament tears were increasingly associated with articular cartilage destruction as the elapsed time from injury to arthroscopy increased.     

Articular cartilage restoration of the knee

Articular cartilage defects are common and play a significant role in degenerative joint disease. Cartilage is unable to regenerate, secondary to an inherent lack of vascular supply, thus, various techniques have been described in an attempt to treat and potentially restore these defects. Treatment decisions should be based on appropriate evaluation and classification of the pathology. Only then can the surgeon choose to perform a repair or a restoration of the articular surface. Current literature and techniques for the treatment of articular cartilage defects are reviewed, with an algorithm developed for the management of articular cartilage defects by orthopaedic surgeons.     

Interindividual variability and correlation among morphological parameters of knee joint cartilage plates: analysis with three-dimensional MR imaging

OBJECTIVE: To determine the range and variability of the cartilage volume, thickness, and articular surface areas in the knee joints of healthy male subjects, the association of these parameters within and between the knee joint cartilage plates, and their correlation with anthropometric variables. METHOD: The right knees of 27 individuals (age 23 to 64 years) without cartilage damage were examined. Sagittal magnetic resonance imaging was with a fat-suppressed gradient echo sequence (resolution 2 x 0.31 x 0.31 mm(3)), quantitative parameters being computed for all cartilage plates. RESULTS: The total knee joint cartilage volume ranged from 16.6 to 31.4 ml, the size of the articular surfaces from 102 to 163 cm(2), and the mean cartilage thickness from 1.57 to 2.43 mm. The mean and maximal cartilage thickness were highest in the patella (2.76 and 5.72 mm). There was a significant correlation of the cartilage volume with the mean thickness (R=0.80) and with the joint surface areas (R=0.56), but not between the thickness and surface area (R=0.37). The association among the patella, tibia, and femur was 0.16 to 0.72 for volumes, 0.08 to 0.78 for thickness, and 0.24 to 0.62 for surfaces. The knee joint cartilage volume and the surface areas were significantly associated with the body height (R=0.51 and 0.57), but not the cartilage thickness (R=0.22). CONCLUSION: There is a surprisingly high variability of the quantitative distribution of cartilage within the knee joint, with only moderate correlations between knee joint cartilage plates, and this variability cannot be adequately predicted based on anthropometric variables.     

MRI序列及三维重建在膝关节软骨损伤的诊断价值

目的观察脂肪抑制三维扰相梯度回波序列（FS-3D-SPGR）、FS-FSE-T2W序列及三维重建对软骨损伤的诊断价值。方法41个膝关节关节面共205个区域进入研究,MR检查至少包括FS-FSE-T2W、3D-FS-SPGR序列,对损伤进行分级。在工作站上采用HDMIP进行三维重建,其结果与关节镜对照。结果3D-FS-SPGR序列对软骨损伤显示的敏感度为89．47％,特异度为97．65％;FS-FSE-T2W序列的敏感度为78．57％,特异度为94．71％。结论3D-FS-SPGR能准确评价关节软骨的损伤程度,但对软骨下骨及骨髓损伤不敏感;FS-FSE-T2W能准确反应软骨下骨及骨髓损伤的程度及范围,二者结合是目前诊断软骨损伤的最佳扫描序列。关节软骨的三维重建图像能够较真实准确地显示软骨损伤的部位与范围。     

The acute structural changes of loaded articular cartilage following meniscectomy or ACL-transection

Objective Meniscectomy and anterior cruciate ligament (ACL) rupture have been identified as precursors of osteoarthrosis (OA) in clinical reviews and animal experiments. In this study, the acute effects of these injuries on articular cartilage matrix deformation, preserved in a loaded state using a cryopreservation technique, were studied by scanning electron microscopy (SEM).Method Whole knee joints from adult White New Zealand rabbits (N=87) were loaded ex vivo, using a simulated quadriceps pull under static and cyclic loading conditions, following medial meniscectomy or transection of the ACL. Specimens were plunge-frozen while under load, or following a recovery period, and prepared for SEM by cryofixation. Using SEM and photographic images, the medial tibial plateau cartilage was assessed both qualitatively and quantitatively.Results After meniscectomy, significantly increased bending and crimping of radial collagen fibers occurred with static loading. Compared to intact knees, the area of tibial cartilage showing an indentation was increased by 80% (P< 0.05), the articular cartilage thickness was significantly more reduced when under load (for high force long duration static loading, intact joints had 53%±3 reduction in cartilage thickness compared to 39%±4 after meniscectomy, P< 0.05), and it took nearly twice as long for the cartilage thickness to recover following loading. These post-meniscectomy differences were either not present or were minimal when the joint was allowed to extend when loaded. ACL-transection slightly increased collagen deformation in the deeper zones, but only with cyclic loading.Conclusion The findings indicate that, with static loading, significantly increased deformation of articular cartilage collagen structure can occur following meniscectomy, but is minimized by joint motion. This increased deformation may be relevant to the etiology and progression of joint degeneration.     

Softening of canine articular cartilage after immobilization of the knee joint

Using the indentation method, effects of immobilization with a splint for 11 weeks on the stiffness of the articular cartilage in the canine knee were investigated. Stiffness was determined for femoral, tibial, and patellar articular cartilages with nine, eight, and three test points, respectively, in the form of elastic moduli. Immobilization, without causing any macroscopic changes on cartilage surface, influenced the quality and quantity of articular cartilage. Immobilization caused significant softening of the femoral and tibial cartilages. The rate of deformation under the test load increased (42%) and the average thickness of the cartilage decreased (9%) as compared with the controls. Normal cartilage stiffness remained in the contact area between the patella and patellar surface of the femur, probably as a consequence of the sustained, but not forceful, loading between the femur and the patella produced by the flexion of the knee joint.     

The femoro-patellar joint and cartilage damage of the knee joint

This article surveys the update knowledge of diagnosis and treatment of damage to the cartilage with particular reference to the femoropatellar joint. Complementary to this the biomechanical fundamentals and special anatomic features are explained, the knowledge of which is imperative for an understanding of the complex linkups and interconnections.     

Traumatic cartilage damage of the knee joint

Thirty-five traumatic lesions to cartilage were recorded, together with other injuries, from 225 arthroscopic examinations in two years. Most of the lesions (20) were located at the femoral condyle. The patella was involved in eight cases. However, if the patellar surface was related to the surface of the femoral condyles, the former was just as strongly affected by traumatic effects as the latter. No unambiguous localisation was possible in six cases, most of them smaller cartilage abrasions. Optional therapy proved to be applicable via the arthroscope in seven cases, while small incisions in the form of mini-arthrotomy were necessary in five cases. Arthrotomy was performed on 21 patients, and no therapeutic action at all was required in two cases. Complications included one transient soft-tissue infection and haemarthrosis of one patients who had to be punctured. Following very short-time immobilisation in plaster cast, the use of forearm walking supports was considered appropriate for short-term weight relief. A weight-relieving orthotic device with dynamic partial-loading facility was fitted for longer-term weight relief.