Differences in cellular properties and responses to growth factors between human ACL and MCL cells

The anterior cruciate ligament (ACL) has poor healing responses compared with those of the medial collateral ligament (MCL). It has been implied that this is partially due to the poor reparative capacity of ACL cells for ligament injury. The present study was designed to elucidate the reparative capacities of human ACL and MCL cells by investigating their cellular properties and their responses to growth factors. Human ACL and MCL were obtained from seven fresh human cadavers. The cells were isolated from each tissue, and primary cultures were used for the examination. The growth rates of all the human ACL cells were lower than those of the human MCL cells; consistent with this, the doubling time of the ACL cells was 30 ± 7.4% longer than that of the MCL cells. The chemotactic migration of human ACL cells was 33 ± 8.1% slower and the synthesis of DNA and collagen in human ACL cells was 29 ± 6.3% and 31 ± 9.7% lower, respectively, in comparison with those of MCL cells. Cellular responses, in terms of DNA synthesis, in human ACL cells to either basic-fibroblast growth factor (1.0 and 10.0 ng/ml) or transforming growth factor-β (1.0 ng/ml) were lower than those of human MCL cells. However, no differences in the cellular responses in terms of collagen synthesis were found. Composite data show that human ACL cells have poorer cellular properties and lower responses to growth factors compared with those of human MCL cells, which suggests that the reparative capacity of human ACL cells may be poorer than that of human MCL cells. Received for publication on Sept. 2, 1998; accepted on Jan. 29, 1999     

Complete ACL/MCL deficiency induces variable degrees of instability in sheep with specific kinematic abnormalities correlating with degrees of early osteoarthritis

People are not equally disabled by combined anterior cruciate ligament (ACL)/medial collateral ligament (MCL) injuries, nor do they all develop osteoarthritis (OA). Although biological/biomechanical causes are not clear, some association presumably exists between joint instability and OA development. We hypothesized that degree of OA development following standardized complete ACL/MCL injuries will vary directly with the degree of biomechanical abnormality between individuals. Three groups of sheep were used to test the hypothesis: 17 normal, 9 ACL/MCL transected, and 7 sham animals. Normal joints were assessed morphologically while sham and experimental animals had gait assessment pre‐ and at 4 and 20 weeks post‐surgery, with cartilage and bone changes being mapped and graded at sacrifice at 20 weeks. Sham joints were morphologically normal and had only one minor kinematic change at 20 weeks. Although variable, ACL/MCL deficient animals showed significant kinematic abnormalities in 4/6 degrees of freedom (DOFs), as well as cartilage/bone damage by 20 weeks (p < 0.05). Linear regression analysis revealed that changes in medial–lateral (ML) translation were related to the current level of joint degradation as represented by total gross OA score (p = 0.0044, R² = 0.71) in the ACL/MCL transected group. Even identical ACL/MCL injuries result in inter‐animal variations in instability and OA, however significant kinematic abnormalities in ML translation do relate to early OA in sheep. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 30:384–392, 2012     

Variations in the three-dimensional location and orientation of the ACL in healthy subjects relative to patients after transtibial ACL reconstruction

Recent reports have indicated that anatomical placement of the anterior cruciate ligament (ACL) graft is an important factor for restoration of joint function following ACL reconstruction. The objective of this study was to address a need for a better understanding of anatomical variations in ACL position and orientation within the joint. Specifically, variations in the ACL anatomy were assessed by testing for side-to-side ACL footprint location symmetry in a healthy population relative to the operative and contralateral knee in a patient population after traditional transtibial single-bundle ACL reconstruction. MRI and three-dimensional modeling techniques were used to determine the in vivo tibiofemoral ACL footprint centers and the resulting ACL orientations in both knees of 30 healthy subjects and 30 subjects after transtibial ACL reconstruction. While there were substantial inter-subject variations in ACL anatomy, the side-to-side RMS differences in the ACL footprint center were 1.20 and 1.34 mm for the femur and tibia, respectively, for the healthy subjects and no clinically meaningful intra-subject differences were measured. However, there were large intra-subject side-to-side differences after transtibial ACL reconstruction, with ACL grafts placed 5.63 and 7.64 mm from the center of the contralateral femoral and tibial ACL footprint centers, respectively. Grafts were placed more medial, anterior, and superior on the femur and more posterior on the tibia; producing grafts that were more vertical in the sagittal and coronal planes. Given the large variation among subjects, these findings advocate the use of the contralateral ACL morphology for retrospectively evaluating patient-specific anatomic graft placement.     

关节镜下保留残端手术与常规手术重建前交叉韧带疗效比较

目的比较关节镜下保留残端手术与常规手术重建前交叉韧带(ACL)的疗效。方法采用关节镜下自体腘绳肌腱单束重建治疗66例膝关节ACL断裂患者,其中采用常规手术方法重建治疗37例,保留残端手术方法重建治疗29例。结果 66例均获随访,时间12~28个月。常规手术组及保留残端手术组术后前抽屉试验和Lachman试验比较差异均无统计学意义(P0.05);采用Lysholm、IKDC评分评价膝关节功能:两组术后比较差异均有统计学意义(P0.05),保留残端组优于常规手术组。结论关节镜下保留残端手术与常规手术行自体腘绳肌腱单束重建治疗膝关节ACL损伤都能获得满意的临床疗效,但关节镜下保留残端手术有利于移植物的再血管化及本体感受器的恢复。     

Decreased posterior cruciate and altered collateral ligament loading following ACL transection: A longitudinal study in the ovine model

Although ACL deficiency is shown to lead to joint degeneration, few quantitative data are reported on its effect on soft tissue structures surrounding the knee joint, specifically, the posterior cruciate and collateral ligaments. The kinematics of the stifle joint of sheep (N = 5) were measured during “normal” gait, as well as 4 and 20 weeks after ACL transection. These motions were reproduced using a unique robotic manipulator and the loads borne by PCL, MCL, and LCL during gait were determined. Our results demonstrated a significant decrease in mean PCL loads 20 weeks post‐ACL injury, at hoof‐strike (0% of gait, p = 0.034), hoof‐off (66% of gait, p = 0.006), peak‐swing (85% of gait, p = 0.026), and extension‐before‐hoof‐strike (95% of gait, p = 0.028). Mean MCL loads did not significantly increase following ACL transection, maybe due to large between‐animal variation. Finally, mean LCL loads indicated a significant decrease (p < 0.047) at 20 weeks across the entire gait cycle. From a clinical perspective, the load redistributions observed in cruciate and collateral ligaments following ACL injury indicate that these tissues can carry/adapt to the altered mechanical environment of the joint. The considerable variability in the magnitudes of change following ACL injury among animals also simulates clinical variability in humans after trauma. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:431–438, 2014.     

塞来昔布在膝关节镜下前交叉韧带重建围手术期镇痛的效果分析

[目的] 研究塞来昔布在膝关节镜下自体腘绳肌腱前交叉韧带重建围术期应用的镇痛效果.[方法] 采用随机对照研究方法,对90例前交叉韧带损伤患者行膝关节镜下自体腘绳肌腱重建术,随机分为3组,其中A组应用传统PCA镇痛,B组应用塞来昔布辅助曲马多镇痛,C组采用塞来昔布超前镇痛辅助曲马多镇痛.通过比较3组的术后各时间点VAS评分、术后不良反应发生率及辅助曲马多用量来比较3种方法的临床效果.[结果] 术前3组患者年龄、体重、病情等基本情况无差别.术后6、12、24、48 h,C组及A组VAS评分无差别且均小于B组(P_(6,12,24,48)<0.05);术后A组不良反应发生率为43.3%.大于B组的16.7%及C组的20.0%(x~2=6.3920,P=0.0115);术后A组辅助曲马多用量最少,而B组最多(F_(24)=84.93,P_(24)<0.0001;F_(48)=117.13,P_(48)<0.0001).术后各组中患者均恢复良好,伤口均一期愈合,未出现严重的并发症及过敏反应.[结论] 膝关节镜下自体腘绳肌腱前交叉韧带重建围术期应用塞来昔布超前镇痛辅助盐酸曲马多的镇痛方法,其镇痛效果好,不良反应低,具有良好的临床效果和安全性.     

Vascular structure and function in the medial collateral ligament of anterior cruciate ligament transected rabbit knees

To determine if decreased vascular responsiveness in the medial collateral ligament (MCL) of anterior cruciate ligament transected (ACL‐t) rabbit knees is due to pericyte deficiency associated with angiogenesis. Vascular responses to potassium chloride (KCl), phenylephrine, acetylcholine, and sodium nitroprusside (SNP) were evaluated in ACL‐t rabbit knees (n = 6) and control knees (n = 5) using laser speckle perfusion imaging. Ligament degeneration was determined by ultrasound imaging. Vascular and pericyte volume were measured using quantitative immunohistochemical volumetric analysis using CD31 and α‐smooth muscle actin antibodies with co‐localization analysis. Perfusion was increased in the ACL‐t rabbits 2.5‐fold. Responsiveness to phenylephrine, SNP, and acetylcholine was significantly decreased in the ACL knee while no change in KCl responses was seen. MCL ultrasound imaging revealed decreased collagen organization, increased ligament thickness, and increased water content in the ACL‐t MCL. Vascular Volume was increased fourfold in ACL deficient knees, while pericyte volume to endothelial volume was not changed. No difference in CD31 and α‐SMA co‐localization was found. Blood vessels in the MCL of ACL‐t knees do not lack smooth muscle. The MCL vasculature can undergo constrictive response to KCl, but have impaired receptor mediated responses and impaired nitric oxide signaling. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:1104–1110, 2014.     

ACL reconstruction by bone-patellar tendon-bone graft: mechanical evaluation of the elastic modulus and failure modes

The aim of this study was to apply an engineering approach to study the biomechanical behaviour of both native and reconstructed anterior cruciate ligaments (ACL) under tensile test, simulating the primary stability of the reconstructed ACL in the immediate postoperative period, when the bone callus has not formed yet. We used the bovine bone-patellar tendon-bone grafts to reconstruct ACL in bovine knees. The grafts were fixed by means of titanium interference screws and titanium transverse compressive screws. We tested 18 native and 18 reconstructed ligaments (7 with interference screws and 11 with transverse compressive screws). We applied mechanical tension at a 500 mm/min strain rate, and observed the mode of failure. The data analysis confirmed the different behaviour recorded in load elongation curves, a difference enhanced in stress-strain curves for both fixation methods. The stress-strain patterns for the interference screw and for the native ligament were quite similar.     

Tripeptide–copper complex GHK‐Cu (II) transiently improved healing outcome in a rat model of ACL reconstruction

After anterior cruciate ligament reconstruction (ACLR), the biological healing of the graft is a rate‐limiting step which can contribute to graft failure. The tripeptide–copper complex glycyl‐L ‐histidyl‐L ‐lysine‐Cu(II) (GHK‐Cu) is a well‐known activator of tissue remodeling. We investigated whether GHK‐Cu can improve graft healing following ACLR. Seventy‐two rats underwent unilateral ACLR were randomized to saline, 0.3 or 3 mg/ml GHK‐Cu groups (n = 24). Post‐operational intra‐articular injections were given from week 2, once a week, for 4 weeks. Gait analysis was performed pre‐injury and at harvesting time. At 6 or 12 weeks post‐operation, knee specimens were harvested for knee laxity test, graft pull‐out test, and histology. At 6 weeks post‐ACLR, GHK‐Cu groups resulted in a smaller side‐to‐side difference in knee laxity as compared to the saline group (p = 0.009), but there was no significant difference at 12 weeks post‐operation. The graft complex in the 0.3 mg/ml GHK‐Cu group had higher stiffness than saline group at 6 weeks post‐operation (p = 0.026), but there was no significant difference in ultimate load, gait parameters, and histological scores among treatment groups. All grafts failed mid‐substance during pull‐out test. Intra‐articular supplementation with a bioactive small molecule GHK‐Cu improved graft healing following ACLR in rat, but the beneficial effects could not last as treatment discontinued. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1024–1033, 2015.     

前内侧入路解剖重建单束前交叉韧带的临床评估

目的评估关节镜下经前内侧入路解剖重建单束前交叉韧带(ACL)的位置、形态及临床效果。方法对25例ACL断裂患者在关节镜下经前内侧入路应用解剖重建技术行单束ACL重建术,移植物应用自体腘绳肌腱。术后行X线、MRI检查,了解骨道情况,观察移植物形态及张力,并与11例健侧膝关节的正常ACL进行对比。应用Lysholm评分系统评估膝关节功能。结果术后X线片显示股骨隧道内口位于髁间窝顶与股骨后缘皮质线交叉点前缘,胫骨隧道内口位于髁间窝顶后方。MRI显示所有重建ACL张力良好,ACL上倾角为50.82°±4.57°,胫骨平台止点至前缘距离与平台纵径比值为0.50±0.04,两项与对照组比较差异均无统计学意义(P0.05)。患者均获得随访,时间为13~44个月。Lysholm评分术后为92.20分±4.29分,明显高于术前的64.76分±7.16分(P0.01)。结论关节镜下经前内侧入路解剖重建ACL的位置及形态接近解剖结构,早中期临床效果满意。     

保留残迹对前交叉韧带重建移植物愈合影响的组织学研究

[目的]观察保留残迹对前交叉韧带(anterior cruciate ligament,ACL)重建移植物愈合的影响,并探讨其原因.[方法]新西兰兔30只(封闭群,体重2.9～3.5 kg,平均3.2 kg)随机分为3组,每组10只.取其跟腱为移植物,切断双侧前交叉韧带,随机一侧保留ACL残迹,对侧切除残迹,行前交叉韧带重建.分别于术后4、8、12周处死动物,取关节内重建ACL移植物标本10%多聚甲醛固定、10%EDTA脱钙、包埋、切片,HE染色及Masson、PAS特殊组织化学染色,检测成纤维细胞密度及观察组织学形态,数据采用SPSS 12.0软件进行统计分析.[结果]各时间段保留残迹组移植物HE染色组织切片成纤维细胞密度均高于切除残迹组,两组比较有显著统计学差异(P<0.05),两处理组8周时细胞密度高于4、12周,不同时间段比较有统计学差异(P<0.05).各时间段保留残迹组移植物的组织学表现均优于切除残迹组.[结论]保留残迹ACL重建有利于新生细胞长入替代移植物,促进移植物组织结构成熟.     

Tension patterns of the anteromedial and posterolateral grafts in a double‐bundle anterior cruciate ligament reconstruction

The two functional bundles of the anterior cruciate ligament (ACL), namely, the anteromedial (AM) and posterolateral (PL) bundles, must work in concert to control displacement of the tibia relative to the femur for complex motions. Thus, the replacement graft(s) for a torn ACL should possess similar tension patterns. The objective of the study was to examine whether a double‐bundle ACL reconstruction with the semitendinosus‐gracilis autografts could replicate the tension patterns of those for the intact ACL under controlled in vitro loading conditions. By means of a robotic/universal force moment sensor (UFS) testing system, the in situ force vectors (both magnitude and direction) for the AM and PL bundles of the ACL, as well as their respective replacement grafts, were determined and compared on nine human cadaveric knees. It was found that double‐bundle ACL reconstruction could closely replicate the in situ force vectors. Under a 134‐N anterior tibial load, the resultant force vectors for the intact ACL and the reconstructed ACL had a difference of 5 to 11 N (p > 0.05) in magnitude and 1 to 13° (p > 0.05) in direction. Whereas, under combined rotatory loads of 10‐N‐m valgus and 5‐N‐m internal tibial torques, the corresponding differences were 10 to 16 N and 4° to 11°, respectively. Again, there were no statistically significant differences except at 30° of flexion where the force vector for the AM graft had a 15° (p < 0.05) lower elevation angle than did the AM bundle. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27: 879–884, 2009     

骨洗方联合持续被动活动治疗膝关节镜下前交叉韧带重建术后关节僵硬

目的观察骨洗方联合持续被动活动（CPM）治疗膝关节前交叉韧带（ACL）重建术后关节僵硬的疗效。方法对我院2009年1月至2010年3月24例（24膝）膝关节镜下ACL重建术后关节僵硬患者,随机分为两组（A组、B组）,每组12例,A组给予中药骨洗方（由薄荷、桂枝、半枫荷、两面针、红花、宽筋藤等组成）熏洗联合CPM训练,B组仅进行CPM训练,定期随访,以Lysholm膝关节功能评估系统（0-100分）和膝关节活动度（ROM）分别评估膝关节功能。结果 24例患者均获得随访,A组随访时间6-12个月,平均随访10个月,B组随访时间7-12个月,平均10.5个月。A组ROM由治疗前78.6°±16.2°（62-95°）,提高到治疗后125.5°±12.1°（112-135°）,差别有统计学意义（t=8.035,P〈0.001）。B组由治疗前80.2°±13.7°（65-91°）提高到治疗后115.4°±10.1°（102-131°）,差别有统计学意义（t=7.164,P〈0.001）。A、B组治疗前ROM无统计学差异（t=0.261,P〉0.05）,治疗后ROM有统计学差异（t=2.220,P〈0.05）。A组Lysholm评分由治疗前74.3±5.8,提高到治疗后86.7±6.5,差别有统计学意义（t=4.931,P〈0.001）。B组Lysholm评分由治疗前72.7±6.3,提高到治疗后81.5±5.5,差别有统计学意义（t=3.645,P〈0.001）。A、B组治疗前Lysholm评分无统计学差异（t=0.647,P〉0.05）,治疗后Lysholm评分有统计学差异（t=2.116,P〈0.05）。两组无一例患者出现皮肤过敏等并发症。结论中药骨洗方熏洗联合CPM训练对膝关节镜下ACL重建术后关节僵硬患者的膝关节活动功能恢复有明显的促进作用,且效果优于单纯行CPM训练。     

前交叉韧带重建中两种建立股骨隧道方法的比较

[目的]对关节镜下重建前交叉韧带(ACL)手术中,经胫骨隧道与髌下前内侧入路建立股骨隧道的长度、角度进行比较.[方法]在140例ACL移植重建患者中,70例采用经胫骨隧道、70例经前内入路建立股骨隧道,术中记录股骨隧道长度,术后行膝关节前后位及侧位X线检查,测量股骨隧道在冠状面与内外髁连线及矢状面与股骨干轴线夹角,并使用t检验进行统计分析.[结果]经胫骨隧道组及经前内人路组股骨隧道长度分别为(50.67±5.00) mm、(37.97±4.45) mm,后者股骨隧道长度短于前者,差异非常显著(P＜0.01)；冠状面股骨隧道角度两者分别为68.20°±6.92°；矢状面为45.45°±7.47°、32.81°±9.45°,无论在冠状面及矢状面,前内入路组股骨隧道角度均小于胫骨隧道组,差异非常显著(P＜0.01).[结论]在关节镜下ACL移植重建手术中,采用前内入路制备的股骨隧道,长度短、角度小.它可以减小“雨刮效应”和“蹦极效应”发生的可能,最终获得更好的临床效果.     

Medial collateral ligament insertion site and contact forces in the ACL-deficient knee.

The objectives of this research were to determine the effects of anterior cruciate ligament (ACL) deficiency on medial collateral ligament (MCL) insertion site and contact forces during anterior tibial loading and valgus loading using a combined experimental-finite element (FE) approach. Our hypothesis was that ACL deficiency would increase MCL insertion site forces at the attachments to the tibia and femur and increase contact forces between the MCL and these bones. Six male knees were subjected to varus-valgus and anterior-posterior loading at flexion angles of 0 degrees and 30 degrees. Three-dimensional joint kinematics and MCL strains were recorded during kinematic testing. Following testing, the MCL of each knee was removed to establish a stress-free reference configuration. An FE model of the femur-MCL-tibia complex was constructed for each knee to simulate valgus rotation and anterior translation at 0 degrees and 30 degrees, using subject-specific bone and ligament geometry and joint kinematics. A transversely isotropic hyperelastic material model with average material coefficients taken from a previous study was used to represent the MCL. Subject-specific MCL in situ strain distributions were used in each model. Insertion site and contact forces were determined from the FE analyses. FE predictions were validated by comparing MCL fiber strains to experimental measurements. The subject-specific FE predictions of MCL fiber stretch correlated well with the experimentally measured values (R2 = 0.95). ACL deficiency caused a significant increase in MCL insertion site and contact forces in response to anterior tibial loading. In contrast, ACL deficiency did not significantly increase MCL insertion site and contact forces in response to valgus loading, demonstrating that the ACL is not a restraint to valgus rotation in knees that have an intact MCL. When evaluating valgus laxity in the ACL-deficient knee, increased valgus laxity indicates a compromised MCL.     

Joint kinematics and in situ forces after single bundle PCL reconstruction: a graft placed at the center of the femoral attachment does not restore normal posterior laxity

Introduction: Femoral tunnel placement has a great influence on the clinical outcome after PCL reconstruction. Materials and methods: Using a robotic/universal force moment sensor (UFS) testing system, we examined joint kinematics and in situ forces of human knees following soft-tissue single bundle PCL reconstruction fixed at the center of the femoral attachment. Results: Posterior tibial translation significantly increased at all flexion angles after transsection of the posterior cruciate ligament (p<0.05). PCL reconstruction resulted in significantly less posterior tibial translation at all flexion angles when compared to the PCL deficient knee (p<0.05). The differences in the in situ force between the intact ligament and the reconstructed graft were statistical significant (p<0.05). Conclusion: Single bundle PCL reconstruction with a soft-tissue graft fixed at the center of the femoral attachment is able to reduce the posterior tibial translation significantly. However, it cannot restore kinematics of the intact knee and in situ forces of the intact PCL.     

Comparison of volumetric bone mineral density in the operated and contralateral knee after anterior cruciate ligament and reconstruction: A 1‐year follow‐up study using peripheral quantitative computed tomography

The purpose of this study was to quantify changes in volumetric bone mineral density (vBMD) in the tibial plateau of the operated and contralateral leg measured using peripheral quantitative computed tomography (pQCT) before and 3, 6, and 12 months after anterior cruciate ligament (ACL) reconstruction. The ACL was reconstructed with a hamstring tendon autograft using press‐fit fixation. pQCT measurements of the proximal tibia were obtained in 61 patients after ACL reconstruction, and total, cortical, and trabecular vBMD were calculated. vBMD in the operated leg decreased from baseline to 3 months (?12% [total], ?11% [cortical], and ?12.6% [trabecular]; p < 0.001) and remained below baseline for 12 months after surgery (6 months: ?9.5%, ?9.4%, and ?9.6%, p < 0.001; 12 months: ?8%, ?5%, and ?11%, p < 0.001). vBMD in the contralateral leg was slightly reduced only 6 months after surgery. Including age and sex as covariates into the analysis did not affect the results. ACL reconstruction contributed to loss in bone mineral density within the first year after surgery. The role of factors such as time of weight‐bearing, joint mechanics, post‐traumatic inflammatory reactions, or genetic predisposition in modulating the development of posttraumatic knee osteoarthritis after ACL injury should be further elucidated. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1804–1810, 2015.