双骨道与三骨道前交叉韧带双束重建的生物力学比较

背景:关节镜下前交叉韧带重建可以有效地解决前交叉韧带损伤引起的膝关节不稳症状,而双骨道(胫骨单骨道-股骨单骨道)与三骨道(胫骨单骨道-股骨双骨道)前交叉韧带重建是目前较为常用的重建方式。目的:探讨双骨道与三骨道前交叉韧带双束重建对膝关节稳定性的影响。方法:选用8具新鲜正常成人尸体膝关节标本,分别进行双骨道与三骨道前交叉韧带双束重建,然后在MTS-809生物力学测试系统上测试膝关节在胫前加载(134N)以及胫骨旋转加载(5Nm内旋)下屈曲0°,15°,30°,60°,90°时的膝关节稳定性。结果与结论:①胫前加载:在所测的5个角度下,两重建组的胫前位移较前交叉韧带完整组均增大,但差异无显著性意义(P>0.05);双骨道重建组较三骨道重建组胫前位移增大,但差异无显著性意义(P>0.05)。②旋转加载:在所测的5个角度下,前交叉韧带完整组的胫前位移最小,双骨道重建组与三骨道重建组比较,在膝关节屈曲0°,15°和90°时,差异无显著性意义(P>0.05),在膝关节屈曲30°和60°时,三骨道重建组胫前位移小于双骨道重建组,差异有显著性意义(P<0.05);三骨道重建组与前交叉韧带完整组比较,差异无显著性意义(P>0.05)。提示双骨道与三骨道前交叉韧带双束重建均可促进膝关节前后及旋转稳定性的恢复,三骨道前交叉韧带双束重建与双骨道前交叉韧带双束重建相比,显示了更好恢复膝关节旋转稳定性的作用。     

计算机导航技术在后交叉韧带重建胫骨隧道定位中的应用

背景：后交叉韧带重建中胫骨隧道的定位一直是手术的难点,把计算机导航技术运用到后交叉韧带重建中,希望能提高胫骨隧道定位的精度。目的：采用计算机导航系统在重建膝关节后交叉韧带中准确定位胫骨隧道的方法,评价其在后交叉韧带重建中的应用价值。方法：甲醛防腐成人下肢标本50侧,切断标本后交叉韧带后分别用聚氨酯海棉粘贴包裹模拟软组织覆盖的完整标本。随机分成两组,分别采用计算机辅助导航系统（导航组）及传统关节镜（对照组）定位胫骨隧道。观察两组标本胫骨隧道的出口位置,透视后测量胫骨隧道的矢状角度及长度,记录透视次数。结果与结论：导航组胫骨虚拟隧道矢状角度和长度术中定位及术后实测比较差异均无显著性意义（P〉0.05）。导航组术后实测胫骨隧道矢状角度为（61.88±0.94）°、透视次数为（3.0±0.5）次,对照组分别为（52.63±1.04）°及（9.0±2.7）次;导航组隧道出口位于后交叉韧带生理附着区23例,对照组为15例;两组比较差异均有显著性意义（P〈0.05）。结果提示透视导航技术可以辅助后交叉韧带重建手术中胫骨隧道的定位,具有隧道定位准确性高、辐射及手术污染机会减少的特点。     

Influence of the tunnel angle in ACL reconstructions on the biomechanics of the knee joint

BACKGROUND: A high tension in anterior cruciate ligament grafts affects both graft and knee functional performance. Clinical observations suggest that impingement of the graft against the posterior cruciate ligament might cause high graft tensions. Also, meniscal injury has been well documented in association with damage in the anterior cruciate ligament. METHODS: In this paper, we present the results obtained in a three-dimensional finite element model of the human knee, corresponding to different aspects of anterior cruciate ligament reconstruction with bone-patellar tendon-bone grafts. This model was used to investigate the effect of the angle in the coronal plane of femoral and tibial tunnels. Firstly, graft tension was computed in a knee moved from 0 degrees to 60 degrees of flexion and the results were compared with experimental ones obtained by other authors. Secondly, the resulting kinematics under an anterior load of 134 N was compared to that of the intact knee. FINDINGS: The obtained results showed that the closest anterior tibial translation to that of the intact knee was obtained with femoral and tibial tunnels with angles of 60 degrees. In this same case, a lower graft tension was also obtained. The results demonstrated noticeable increases in the meniscal stresses after anterior cruciate ligament reconstruction. INTERPRETATION: Our results showed that impingement only depends on the femoral tunnel angle. On the contrary, laxity principally depends on the tibial tunnel angle. The angle of the femoral tunnel affects the graft tension while the tibial tunnel affects laxity, meniscal stresses and strains.     

Comparative investigation on the biomechanical properties of ligament replacement in the sheep knee using six different ligament prostheses

Six different ligament prostheses were implanted in 40 sheep to replace the anterior cruciate and medial collateral ligament of the right knee. After one year the explanted knee joints were tested for stability by measurement of the anterior drawer. Tensile tests on the ligament replacements were performed to determine the stiffness and rupture force of the replacement. Gross inspection of the knee joint showed abrasion and partial ruptures for all types of prostheses after one year. Depending on the type of prosthesis total rupture rates between 0 and 66% of all implants could be seen. The anterior drawer for the operated knee was 3-4 times higher than for the non-operated contralateral side. Neither the stiffness nor the rupture strength of the replacements reached the biomechanical properties of the normal ligaments.     

计算机导航技术辅助后交叉韧带重建中胫骨隧道的规划及定位

背景:常规后交叉韧带重建术可改善关节的后向稳定性,但移植物与胫骨隧道口之间相互磨损,使移植物机械强度下降或隧道口扩大而导致后交叉韧带术后残存松弛.目的:利用基于术中透视的计算机导航技术,辅助关节镜下后交叉韧带重建手术中胫骨隧道的合理规划及准确定位,探讨导航技术在后交义韧带重建手术中的有效性与实用性.设计、时间及地点:病例分析,于2006-08/2007-03北京积水潭医院完成.对象:后交叉韧带重建手术患者15例均为复合韧带损伤.14例选用异体跟腱移植,1例选用自体骨髌韧带中1/3一骨移植.方法:导航系统需要在胫骨及后交叉韧带胫骨导向器上分别安装追踪器,经过注册及校准后,导航系统识别并捕获上述追踪器主动发射的信号,实时计算确定胫骨近端的三维空间位置及与胫骨导向器的相对关系,并将后交叉韧带重建中所需要的虚拟胫骨隧道路径叠加至由术中"℃"型臂X射线透视机所获得的胫骨近端X射线影像上.根据规划方案术中实时调整虚拟隧道的位置,正位影像隧道出几位于两侧髁间嵴中线偏外侧、关节面远侧1.5cm处,侧位影像上要求在保证胫骨近端后侧皮质完整的情况下、与胫骨平台关节线角度呈最大.主要观察指标:手术中透视时间和次数,术后标准正、侧位X射线片、三维CT及MRI评估胫骨隧道的出口位置、移植物与隧道的角度、隧道与胫骨后方皮质的贴合程度及隧道后壁的完整性.结果:15例患者中14例获得手术成功,1例失败.手术中透视次数由2～15次减少至2～4次,透视时间缩短10～30 min.无导航相关并发症出现.14例获得成功的病例隧道出几均位于后交义韧带的解剖附丽区内,胫骨隧道与移植物夹角平均为123.3°;隧道与胫骨后办皮质贴合紧密,贴合距离均存2 min内.10例隧道后壁完整,4例轻度破裂但隧道整体完整性存在.结论:透视导航技术可辅助后交叉韧带重建术中胫骨隧道的快速定位,获得准确的隧道口位置和控制合理的隧道角度,具有节省透视时间、准确性高的特点.     

Biomechanical evaluation of a new reconstruction technique of the ulnar collateral ligament in the elbow with modified bone tunnel placement and interference screw fixation

Background

A new method for reconstruction of the anterior bundle of the ulnar collateral ligament using modified bone tunnel placement and interference screw fixation was developed to minimize operative dissection, improve graft tensioning, and reduce associated operative morbidities. The objective of this study was to compare varus–valgus laxity and failure properties of this new ulnar collateral ligament reconstruction to the intact ulnar collateral ligament.

Methods

Nine matched pairs of cadaveric upper extremities were used, the intact ulnar collateral ligament as the control for the load to failure properties and the contralateral arm for ulnar collateral ligament reconstruction. Varus–valgus laxity was measured at 30°, 50°, 70°, and 90° of elbow flexion for intact, ulnar collateral ligament transected, and ulnar collateral ligament reconstruction. Ulnar collateral ligament reconstruction was performed using a tendon graft passed through a bone tunnel and looped around the medial column of the humerus without dissection of the ulnar nerve. Distally, the graft was looped through a bone tunnel in the proximal ulna. Both ends were secured with interference screws. The specimens were loaded to failure at 50° of flexion at a rate of 30 deg/s. Repeated measures analysis of variance with a P value of 0.05 was used.

Findings

Elbow laxity significantly increased with ulnar collateral ligament transection. Following reconstruction, varus–valgus laxity at 30° and 50° of elbow flexion was completely restored to the intact state, only partially restored at 70°, and not changed at 90°. There was no significant difference between the yield and ultimate torques for the intact vs. reconstructed elbows. The angular displacement at yield and failure was significantly greater for the reconstructed elbows compared to the intact.

Interpretation

This reconstruction technique provides comparable strength to that of the native ligament. While stability was improved, failure occurred at greater angular displacement for the reconstructed limbs.     

An implant-free double-bundle reconstruction of the anterior cruciate ligament: operative technique and influence on tibiofemoral kinematics

Background

Reconstruction of the anterior cruciate ligament is a standard surgical procedure in sports traumatology. The widespread replacement method using hamstring tendons has an important shortcoming namely delayed or missing bony healing in contrast to patellar tendon grafts where implant-free fixation is established by using the adjacent bone blocks. The purpose of this study was to describe a new implant-free surgical procedure using hamstring tendon grafts and to analyse the influence on tibiofemoral kinematics in vitro.

Methods

Nine human knee specimens with arthroscopically transected anterior cruciate ligaments were mounted on a dynamic knee simulator and weight-bearing muscle-loaded knee flexions were simulated while a robotic universal force sensor system was used to provide external tibial loads. Three different loading conditions were simulated including partial body weight only, an additional 50 N anterior tibial force or an additional Five Nm of internal rotational torque. After reconstruction of the anterior cruciate ligament using a tibial bone block hybrid technique these three trials were repeated. The kinematics was measured with an ultrasonic measuring system and different loading and ligament conditions were examined. Graft tunnel placement was verified by computed tomography.

Findings

Our fixation method achieved stability to anterior tibial drawer force whereas internal tibial rotation did not change before and after the reconstruction. Computed tomography confirmed anatomical graft and tunnel placement.

Interpretation

The presented operative procedure is technically feasible and leads to reproducible results concerning knee joint kinematics and graft placement.     

Cyclic testing of tibialis tendon allografts for anterior cruciate ligament reconstruction using suture-post versus spiked washer tibial fixation

BackgroundThe purpose of this study was to directly compare spiked washer and suture-post tibial-sided fixation techniques used for anterior cruciate ligament reconstruction by measuring anterior tibial translation during cyclic tests.MethodsFresh-frozen human knees were tested using a robotic system that applied 250 cycles of anterior-posterior tibial force (134 N) at 30° flexion, while recording tibial translation. Ten intact knees were tested to collect baseline data for native specimens. A single knee was selected to test ligament reconstructions using doubled tibialis tendon allografts. All grafts were fixed proximally using an EndoButton™, and the tibial end of the graft was fixed with either a spiked washer or with a suture post placed at two different locations (near and distant) relative to the tibial tunnel.FindingsMean first cycle translation for intact knees was 4.8 (sd 1.8) mm; means after reconstruction were 2.6 (sd 0.9) mm (spiked washer), 10.1 (sd 1.9) mm (suture post near), and 10.4 (sd 1.5) mm (suture post distant). Corresponding means for translation increase over 250 cycles were 0.3 (sd 0.2) mm, 3.6 (sd 1.3) mm, 7.2 mm (sd 0.9) mm, and 8.0 (sd 1.3) mm. All mean increases (first cycle and cyclic) after ACL reconstruction were significantly greater than those for the intact knees, and all means with a suture post were significantly greater than those with a spiked washer. There were no significant differences between mean translations for near and distant suture post locations.InterpretationUse of suture post fixation for anterior cruciate ligament reconstruction is questioned since increases in anterior tibial translation could lead to excessive post-operative knee laxity and possibly early clinical failure.     

Korrektur der tibialen Tunnelposition durch exzentrisches ��berbohren

A correctly positioned anatomical tunnel is the most important factor for successful cruciate ligament replacement. Incorrect placement of the bone channel is the most common cause for revision. Excentric overdrilling represents an easily carried out and safe correctional option for slightly incorrect placement of the tibial drill channel during arthroscopic reconstruction of the anterior cruciate ligament. In contrast pedrilling of a new tibial bone channel is often complicated by the new channel merging with the previously drilled channel.     

The effect of localized leg muscle fatigue on tibial impact acceleration

OBJECTIVE: The objective of this study was to assess the effect of localized leg muscle fatigue on tibial acceleration following impact. BACKGROUND: Peak tibial accelerations measured just distal to the knee joint during running have been shown to increase with general body fatigue. However, the role that local leg muscle fatigue plays in shock attenuation is not clear. METHODS: The unshod, dominant foot of 24 healthy women in two different age groups was impacted into a vertical force plate, using a human pendulum method. Impact velocity and force approximated that found in running. EMG activity of the gastrocnemius and tibialis anterior muscles was monitored during fatiguing isometric exercise to assess fatigue, and quantified at impact as a measure of muscle activation level. A skin-mounted uni-axial accelerometer, was located at the tibial tubercle under pre-load, to measure tibial acceleration at impact. RESULTS: There was a significant decrease in peak tibial acceleration (P = 0.008) and acceleration slope (P = 0.033) following fatigue. There were no significant main effects or interactions for age group or muscle group for all tibial response variables. CONCLUSION: The reduction in peak tibial acceleration following fatigue (for the test performed) is contrary to the response documented following whole-body fatigue.     

Evaluation of the material properties of the subsynovial connective tissue in carpal tunnel syndrome

BACKGROUND: The purpose of this study was to determine the material properties of the normal carpal tunnel subsynovial connective tissue in response to shear stress. METHODS: The shear modulus and maximum shear strength were measured with a custom-made micro-tester in 10 specimens of subsynovial connective tissue from 10 wrists in eight patients with idiopathic carpal tunnel syndrome and in 10 specimens from five fresh frozen cadavers without a history of carpal tunnel syndrome. FINDINGS: The mean shear modulus was 22.8 (SD 15.4)kPa for the patient group and 2.7 (SD 1.8)kPa for the control group. The mean maximum shear strength was 54.6 (SD 20.3)kPa for the patient group and 23.3 (SD 10.7)kPa for the control group. The values for the patient group were significantly higher than the control group (P<0.05). INTERPRETATION: The material properties of subsynovial connective tissue are altered in patients with idiopathic carpal tunnel syndrome. The impact, if any, of these altered properties on carpal tunnel syndrome remains to be elucidated.     

Vereinfachtes Fadenmanagement beim arthroskopischen HKB-Ersatz

The number of arthroscopic procedures for replacement of the posterior cruciate ligament (PCL) is increasing. Most studies in the literature deal with the different operation techniques concerning tunnel positioning or graft fixation. There are only few papers describing practical details on suture management and graft transport through the tibial and femoral tunnel and around the posterior edge of the tibia (killer turn). However, it is during these steps of the operation that technical problems sometimes occur, which may endanger an easy and quick operation. In this article a simplified concept for suture management is presented facilitating graft insertion and transport in arthroscopic PCL reconstruction according to routine techniques for shoulder arthroscopy.     

Biomechanics of the transverse carpal arch under carpal bone loading

BackgroundCarpal tunnel release and conservative interventions are widely used in clinical therapies of carpal tunnel syndrome. The efficacy of these treatment and interventions mainly lies in the exploitation of the mechanical properties of carpal tunnel. This study investigated the structural mechanics of the transverse carpal arch using cadaveric hands.MethodsPaired force was applied to the insertion sites of the transverse carpal ligament at both the distal (hamate–trapezium) and proximal (pisiform–scaphoid) levels of the carpal tunnel. The two pairs of forces were simultaneously applied in an inward or outward direction when the transverse carpal ligament was intact and transected. Transverse carpal arch and carpal tunnel compliance in response to the forces were analyzed. Three-way repeated measures ANOVA were used to examine the effect of the transverse carpal ligament status (intact/transected), the level of the carpal tunnel (distal/proximal) and the force application direction (inward/outward) on the biomechanics of the transverse carpal arch.FindingsTransverse carpal ligament plays a stabilizing role in resisting outward deformation of the carpal tunnel. The carpal tunnel at the proximal level is more flexible than the carpal tunnel at the distal level. The carpal tunnel is more compliant under the inward force application than under the outward force application.InterpretationThe understanding of carpal tunnel mechanics potentially helps to improve the existing strategies and to develop alternatives for the treatment of carpal tunnel syndrome.     

The use of a hydrogel implant in the repair of osteochondral defects of the knee: A biomechanical evaluation of restoration of native contact pressures in cadaver knees

BackgroundOsteochondral injuries have been treated by a variety of methods, each having its own drawbacks. The purpose of this study was to determine the biomechanical feasibility of using a hydrogel implant replacement for an osteochondral core defect. The hypothesis of this study was that the contact pressure of the native knee can be recreated with the use of a hydrogel implant.MethodsSix cadaver knees were tested in a knee simulator while contact pressures were measured on the tibial plateau. Pressure data was collected in the intact knee, after coring of the condyle and after insertion of a hydrogel implant. Following 1000 gait cycles of fatigue testing, each knee was taken through axial loading indentation testing where the stiffness of the in situ implant was compared to the contralateral condyle.FindingsWhile coring significantly reduced the peak pressure at the coring site from 1.8 MPa in the intact knee to 0.0 MPa after coring, implant insertion significantly increased it to 1.2 MPa. There was no significant difference in the peak pressures or the average pressures at the hole location between the intact knee and following implant insertion. After fatigue testing, no macroscopic loosening or implant damage was observed. Based on indentation testing, the stiffness of the medial condyle, 157 N/mm, was significantly less than the lateral condyle, 696 N/mm.InterpretationThe insertion of the hydrogel implant was able to achieve restoration of contact pressures in the knee supporting the viability of hydrogel implants in the treatment of osteochondral lesions of the knee.     

前交叉韧带重建失败后的首次翻修

背景：前交叉韧带重建失败可由多种因素引起,需要进行翻修手术治疗。国内关于前交叉韧带翻修的报道较少。目的：分析前交叉韧带重建失败后行翻修治疗的主要原因、适应证、方法及效果。方法：前交叉韧带重建后失稳需要接受翻修患者30例,均在关节镜下行探查与翻修治疗。翻修后应用KT-2000、国际膝关节评分委员会评分标准（IKDC）、Lysholm及Tegner评分系统进行评价。结果与结论：30例患者中,初次手术选用自体骨-髌腱-骨移植物9例,自体半腱股薄肌腱14例,同种异体腘绳肌腱7例,翻修原因上、下两端骨道均偏前8例,上骨道偏前12例,下骨道偏前8例,其中1例合并关节强直;自体骨-髌腱-骨重建固定上骨道内骨块的挤压螺钉位置异常1例;内侧副韧带股骨止点撕脱骨折未予修复1例。翻修术中重建的前交叉韧带完全断裂和吸收12例,韧带有部分连接但已明显松弛失张力18例。无骨道骨质严重缺损,均一期行前交叉韧带翻修手术,重建移植物采用同侧腘绳肌腱（STG）10例,对侧腘绳肌腱14例,人工韧带6例。前交叉韧带翻修后KT-2000检查膝关节屈曲90°和30°平均差值,以及IKDC、Tegner和Lysholm评分均较翻修前有明显改善。前交叉韧带重建手术失败的原因较多,但主要与手术骨道位置异常、固定失效、复合韧带损伤处理不当、关节强直等有关。前交叉韧带翻修后膝关节的主观功能和客观稳定性可获得明显改善。     

Biomechanical evaluation of a novel dynamic posterior cruciate ligament brace

BackgroundUse of a rigid brace or cast immobilization is recommended in conservative treatment or postoperative rehabilitation after a posterior cruciate ligament injury. To prevent the loss of knee joint function and muscle activity often associated with this, a flexible knee brace has been developed that allows an adjustable anteriorly directed force to be applied to the calf in order to prevent posterior tibial translation. The purpose of this biomechanical study was to evaluate the impact of this novel dynamic brace on posterior tibial translation after posterior cruciate ligament injury and reconstruction.MethodsA Telos stress device was used to provoke posterior tibial translation in seven human lower limb specimens, and stress radiographs were taken at 90° of knee flexion. Posterior tibial translation was measured in the native knees with an intact posterior cruciate ligament; after arthroscopic posterior cruciate ligament dissection with and without a brace; and after posterior cruciate ligament reconstruction with and without a brace. The force applied with the brace was measured using a pressure sensor.FindingsPosterior tibial translation was significantly reduced (P = 0.032) after application of the brace with an anteriorly directed force of 50 N to the knees with the dissected posterior cruciate ligament. The brace also significantly reduced posterior tibial translation after posterior cruciate ligament reconstruction in comparison with reconstructed knees without a brace (P = 0.005).InterpretationPosterior tibial translation was reduced to physiological values using this dynamic brace system that allows an anteriorly directed force to be applied to the calf.     

Probleme bei vorderer Kreuzbandplastik

Bungee effect, bone tunnel expansion and impingement are the main problems complicating reconstruction of the anterior cruciate ligament. Key points for anatomical reconstruction are graft and bone tunnel placement and graft fixation. Using bone-tendon-bone patellar ligament grafts, the press-fit technique has proven to be a useful alternative technique, achieving high primary stability with refilling of the tibial bone tunnel, avoiding postoperative bone tunnel enlargement and addressing the requirements of graft fixation at the anatomical points on the femoral and tibial sites. Fixation of hamstring tendon grafts is subject to the same principles of anatomical repair; particularly important are shortening the free graft length, reducing the elasticity of the construct, increasing the stiffness and avoiding the movements of the graft in the bone tunnel. Using hybrid fixation techniques prevents graft slipping and bone tunnel widening. Graft impingement should be avoided with intraoperative controls of K-wire placement before drilling the tibial bone tunnel.     

Quantification of the transverse carpal ligament elastic properties by sex and region

Background

The transverse carpal ligament is an integral factor in the etiology of carpal tunnel syndrome. The purpose of this study was to report the biomechanical properties of this ligament and quantify sex-based differences and regional variation in tissue response. We hypothesized that the mechanical response would not be uniform across the surface, and that female ligament properties would have higher strain profiles and lower mechanical properties.

Methods

Uniaxial testing of twelve (six males, six females) human fresh frozen cadaveric transverse carpal ligaments was carried out using an Instron Materials Testing Machine. Strain was measured via a non-contact optical method.

Findings

The following biomechanical properties of the transverse carpal ligament were reported in this work: failure strain (male: 9.2 (SD 5.0), female: 15.5 (SD 7.1)%), strength (male: 4.9 (SD 1.5), female: 4.5 (SD 1.6) MPa), and modulus of elasticity (male: 52.9 (SD 19.6), female: 38.2 (SD 21.9) MPa). The radial side displayed significantly more strain at failure compared to ulnar (P < 0.0001).

Interpretation

The results of this study provide evidence that manipulative treatments should focus stretching on the radial half of the tissue, which experiences larger strains under uniform loading conditions. In addition, this work suggests possible sex-based differences in mechanical properties of the transverse carpal ligament, which could provide a basis for the development of improved non-surgical treatment methods for carpal tunnel syndrome. The results can also be applied to generate more accurate computational models of the wrist.     

关节镜下微创治疗对胫骨髁间棘骨折的疗效

目的 探讨关节镜下复位不同内固定方法治疗胫骨髁间棘撕脱性骨折的疗效.方法 采用关节镜下治疗胫骨髁间棘撕脱性骨折83例,其中Ⅱ型27例,Ⅲ型38例,Ⅳ型18例.在关节镜监视下行骨折复位、利用前交叉韧带胫骨导向器准确确定骨床上的钻孔位置;于胫骨结节内下部经皮向关节腔钻入一个骨隧道;采用双股5号尼龙编织缝线套扎前交叉韧带基底并经骨隧道引出关节外固定于胫骨结节内侧门型钉上.结果 术后83例获得随访6～36个月,平均15个月.术后Lachman和抽屉试验均为阴性.X线片显示除2例骨块前缘有2 mm上撬外均为解剖复位,骨折全部愈合.膝关节活动均正常.结论 关节镜下复位及双股尼龙编织缝线套扎固定治疗胫骨髁间棘撕脱骨折,复位满意、固定可靠;该手术方法简便易行,创伤小,有利于膝关节功能恢复.     

Bone formation and remodeling around implanted materials under load-bearing conditions

Bone formation and remodeling around implanted materials are influenced by the load-bearing conditions. In this study, three types of material were implanted into dog femoral condyles and bone formation and remodeling were observed for 24 weeks thereafter. Even thickening of lamellar bone was observed around bead-coated alumina implants, whereas thick fibrous tissue surrounded by corticalized bone formed around those made of smooth alumina. With an implant made of an artificial osteo-chondral composite material, abundant bone ingrowth into the titanium fibers was observed 8 weeks after the operation and this ingrowth resulted in firm attachment of this composite material to the host bone site. The tibial joint surface against the polyvinyl alcohol (PVA)-hydrogel articular surface of this implant remained intact, which suggests this artificial osteochondral composite material is a very promising joint prosthetic material.