Isolated posterior cruciate ligament insufficiency induces morphological changes of anterior cruciate ligament collagen fibrils.

We studied the ultrastructural changes of the human anterior cruciate ligament (ACL) with transmission electron micrograph cross-sections following isolated posterior cruciate ligament (PCL) injury. Biopsy specimens were obtained from the proximal third and anteromedial aspect of the ACL. Fourteen patients with PCL-deficient knees at a mean of 22.1 months from injury to surgery and 5 normal knees amputated secondary to malignant tumors or traumatic injuries were used as controls. A significant difference was found in the number of collagen fibrils per 1 microm2 between the PCL-deficient knee group and the control group. There was a significant difference found in the collagen fibril diameter between the PCL-deficient knee group and the control group. The collagen packing density (the percentage of sampled area occupied by collagen fibrils) was also significantly different between the PCL-deficient knee and the control group. The current study shows that an isolated PCL insufficiency can induce morphological changes in ACL collagen fibrils, suggesting that a PCL insufficiency can have adverse effects on other ligamentous structures in the knee joint.     

Approach to meniscal tears in anterior cruciate ligament reconstruction

It is generally accepted that meniscus repair in a knee with persistent anterior cruciate ligament (ACL) insufficiency leads to a higher retear rate, and that meniscal repair in conjunction with ACL reconstruction is associated with a higher rate of meniscal healing compared with patients who do not undergo ACL reconstruction. In this article, we will review the background of thses concepts and present treatment strtegies for meniscal tears in ACL-insufficient knees, with particular attention to meniscal repair and meniscal allograft transplanatation.     

The Functional Status of the ACL in Varus OA of the Knee: The Association With Varus Deformity and Coronal Tibiofemoral Subluxation

BackgroundThe present article analyzes the association of the functional anterior cruciate ligament (ACL) status and the overall varus deformity and coronal tibiofemoral subluxation (CTFS) in varus OA of the knee.MethodsOne hundred consecutive knees with varus OA in 84 patients were prospectively included. Knees were divided into two groups, in accordance with the ACL status (functionally sufficient or insufficient). All included patients were potential candidates for unicompartmental knee arthroplasty with predominantly medial compartment OA. Knees with Kellgren/Lawrence ≥ grade 3 in the lateral compartment were excluded leaving 79 knees to be included in this study. Mechanical varus deformity and CTFS were evaluated on AP radiographs and valgus stress radiographs, and compared between the two groups.ResultsKnees with a functionally insufficient ACL had significantly more varus deformity on hip-to-ankle AP standing radiographs (P = .001) and on valgus stress radiographs (P = .017). CTFS on AP standing radiographs was significantly higher (P = .045) in knees with a functionally insufficient ACL. Seventy-three percent (8/11) of the ACL-insufficient knees had a varus deformity of ≥10° and 64% (7/11) of ACL-insufficient knees had CTFS ≥ 6mm. By contrast, only one patient (2%, 1/41) with an insufficient ACL had< 10° varus deformity and a CTFS of < 6mm.ConclusionFunctional ACL insufficiency in osteoarthritic varus knees is associated with greater varus deformity and more advanced CTFS. Seventy-three percent of ACL-insufficient knees had a varus deformity of ≥10° and 64% of ACL-insufficient knees a CTFS of ≥ 6mm. In the work-up for medial unicompartmental knee arthroplasty, functional ACL insufficiency is likely in knees with varus deformity of ≥10° and CTFS of ≥ 6mm.     

Analysis of the significance of the measurement of acceleration with respect to lateral laxity of the anterior cruciate ligament insufficient knee

The purpose of this study was to assess dynamically the lateral thrust of anterior cruciate ligament (ACL) insufficient knees, and from the findings determine any relationship between ACL insufficiency and the later development of osteoarthritis (OA). We investigated 80 knees in 40 patients awaiting ACL reconstruction and 25 knees of 25 patients, which had undergone ACL reconstruction. An acceleration sensor was fixed to the anterior tibial tubercle and this ’acted’ in two directions – medial lateral and perpendicular. The peak value of the lateral acceleration immediately after heel strike was significantly greater in the ACL insufficient knees when compared to their opposite normal knees. When the periods from injury were compared, the lateral thrust of the injured side after 3 years or more was significantly greater than in the first 3 years. There was no significant difference between the normal knees and the ACL reconstructed knees. The results indicated that the lateral acceleration peak value was significantly greater in the ACL insufficient knees than in their opposite normal knees.

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Résumé   A partir d’une évaluation dynamique de l’instabilité de genoux atteints d’insuffisance du ligament croisé antérieur (LCA), nous avons tenté de déterminer la relation entre l’apparition de l’arthrose du genou et l’insuffisance du LCA. Notre étude a porté sur 40 patients (80 genoux) devant subir une opération de reconstruction du LCA et 25 patients (25 genoux) après l’opération de reconstruction du LCA. Des détecteurs d’accélération ont été placé sur la tubérosité tibiale antérieure. Les pics d’accélération latérale suivant immédiatement le contact au sol du talon étaient significativement plus élevés chez les patients avec un genou atteint d’insuffisance du LCA que chez les patients normaux. Il est également apparu que les pics d’accélération latérale étaient significativement plus élevés dans les cas ou le délai après l’altération du LCA étaient de 3 ans ou plus que dans les cas ou cette période était inférieure à 3 ans. L’opération de reconstruction a permis une diminution significative des pics d’accélération au point que ceux-ci ne présentaient aucune différence significative avec ceux enregistrés avec les genoux normaux.

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Accepted: 14 June 2000     

Anterior cruciate ligament and intercondylar notch in the coronal oblique plane: anatomy complemented by magnetic resonance imaging in cruciate ligament-intact knees.

We assessed the anatomy of the anterior cruciate ligament (ACL) and femoral intercondylar notch on cryosections from one cadaveric knee specimen in the coronal oblique plane oriented parallel to the intercondylar roof. We determined the course of the ACL, the widths of the cruciate ligaments at intersection, and the intercondylar notch configuration on coronal oblique plane magnetic resonance images in 51 adult cruciate ligament-intact knees (25 women, 26 men; age range, 16 to 47 years). The intercondylar notch widths were measured at the notch entrance, at the intersection of the ACL and posterior cruciate ligament (PCL), and at the notch outlet. In the coronal oblique plane, the ACL exhibited a diagonal course from the central and medial part of the anterior intercondylar area of the tibia distally, across the lateral third of the intercondylar notch, to the intercondylar surface of the lateral femoral condyle proximally. At the cruciate ligament intersection, the absolute widths of the ACLs measured on average 6.1+/-1.1 mm in men and 5.2+/-1.0 mm in women representing 31.9% and 31.1% of the ACL/central intercondylar notch width ratios. The absolute widths of the PCLs measured on average 9.6+/-1.3 mm in men and 8.5+/-1.3 mm in women representing 50.4% and 51.4% of PCL/central intercondylar notch width ratios. On average for both groups, men and women, the absolute widths of the PCLs were significantly larger than the absolute widths of the ACLs. However, the relative widths of the cruciate ligaments with respect to corresponding intercondylar notch widths were not significantly different. In the coronal oblique plane, the intercondylar notch widths showed on average a significant decrease from posterior to intersection and from intersection to anterior. At notch outlet, the mean notch width measured 21.4 mm in men and 18.5 mm in women. At intersection, the mean notch width measured 19.1 mm in men and 16.6 mm in women. At notch entrance, the notch width measured 14.6+/-1.8 mm in men and 12.7+/-2.1 mm in women. We recommend magnetic resonance tomography of the knee in the coronal oblique plane oriented parallel to the intercondylar roof as the imaging modality of choice to visualize accurately the anatomic diagonal course of the ACL and its relation to the intercondylar notch and posterior cruciate ligament complex.     

Arthroscopically assisted combined anterior and posterior cruciate ligament reconstruction

This article presents the minimum 2-year results (range, 24 to 48 months) of 20 arthroscopically assisted combined anterior cruciate ligament/posterior cruciate ligament (ACL/PCL) reconstructions, evaluated preoperatively and postoperatively using the Tegner, Lysholm, and Hospital for Special Surgery knee ligament rating scales, and the KT 1000 knee ligament arthrometer (Medmetric Corp, San Diego, CA). There were 16 men or boys, 4 women or girls; 9 right, 11 left; 10 acute, and 10 chronic knee injuries. Ligament injuries included 1 ACL/PCL tear, 2 ACL/PCL/medial collateral ligament (MCL)/posterior lateral corner tears, 7 ACL/PCL/MCL tears, and 10 ACL/PCL/posterior lateral corner tears. ACLs were reconstructed using autograft or allograft patellar tendons. PCLs were reconstructed using allograft Achilles tendon, or autograft patellar tendon. MCL tears were successfully treated with bracing. Posterior lateral instability was successfully treated with long head of the biceps femoris tendon tenodesis. Teguer, Lysholm, and Hospital for Special Surgery knee ligament rating scales significantly improved preoperatively to postoperatively (P = .0001). Corrected anterior KT 1000 measurements improved from preoperative to postoperative status (P = .0078).     

The gross morphology of torn human anterior cruciate ligaments in unstable knees.

To evaluate the presence and incidence of reattachments of torn human anterior cruciate ligaments (ACL), we prospectively investigated 101 patients undergoing arthroscopic ACL reconstruction to study the intra-articular morphology of ACLs under circumstances in which functional healing had failed. Results showed that roughly 72% of these unstable knees had reattachment of the torn ACL to the posterior cruciate ligament (PCL). Eighteen percent had no signs of ACL reattachment but only 2% of previously torn ACLs were absent. These results suggest that even in chronic situations in which the knee remains functionally unstable, human ACLs rarely resorb. It also suggests that torn human ACLs commonly reattach in the knee, mainly to the PCL via a process that is consistent with scarring. While the function of these reattachments is clearly inadequate in people with unstable knees because of a combination of reattachment location, scar quantity, or quality, these results nonetheless show that the intra-articular environment in humans often maintains ACL stumps and it is not totally inhibitory to ACL reattachment via some biological process.     

膝关节前交叉韧带胫骨止点的软组织解剖标记

背景：膝关节前交叉韧带（ACL）重建时,胫骨骨道定位不准会产生重建韧带与髁间窝的撞击或起不到维持膝关节稳定性的作用。因此,确定ACL胫骨止点的位置非常重要。目的：研究膝关节ACL胫骨止点前内束（AMB）和后外束（PLB）与软组织标记后交叉韧带（PCL）和外侧半月板前角的距离,从而明确ACL胫骨止点在胫骨平台的位置,为ACL损伤双束重建提供理论支持。方法：解剖18个膝关节尸体标本（左膝10个,右膝8个）,测量ACL中点、AMB中点、PLB中点与PCL和外侧半月板前角的距离,并分析左、右膝关节是否存在差异。结果：AMB中点与PCL和外侧半月板前角的距离分别为（15.00±3.97）mm和（19.78±4.10）mm;PLB中点与两者的距离分别为（10.17±5.56）mm和（19.50±4.40）mm;ACL中点与两者的距离分别为（12.67±4.52）mm和（19.61±3.87）mm。左右膝关节ACL中点、AMB中点、PLB中点与软组织解剖标记的距离无明显统计学差异。结论：膝关节ACL损伤行手术重建时,可采用PCL和外侧半月板前角作为定位标记。     

Nociceptive sensory innervation of the posterior cruciate ligament in osteoarthritic knees

Introduction

Although the posterior cruciate ligament (PCL) is considered to contain not only proprioceptive but also nociceptive sensory fibers, there is a lack of information about nociceptive sensory innervation of the PCL. We hypothesized that the PCL has constant nociceptive sensory innervation, suggesting the possible source of osteoarthritic (OA) knee pain.

Materials and methods

Innervation of the PCL was examined by immunohistochemistry with particular reference to nociceptive nerve fibers in OA knees. Sensory nerve fibers were semi-quantitatively counted in the PCL of OA knees, comparing with non-OA knees. Protein gene product 9.5 (PGP9.5) as a general neuronal marker and calcitonin gene related peptide (CGRP) as a marker for nociceptive neuron were used.

Results

The PCLs had constant CGRP-immunoreactive (IR) nerve fibers in both OA and non-OA knees. The difference of the CGRP-IR nerve density between groups did not reach a statistical significance (p = 0.062). For PGP9.5-IR nerve fibers, however, the PCLs in OA knees were statistically less innervated than non-OA knees (p = 0.0009).

Conclusions

Our results showed that, in spite of a significant decrease in total innervation in OA knees, the PCLs have constant nociceptive sensory innervation. Although the relationship between the decrease in total innervations in the PCL and OA pathophysiology is still unclear, the PCL is the possible source of OA knee pain. Our results should be taken into account when examining the pain source of the OA knees and handling the PCL during total knee arthroplasty.     

Intercondylar notch measurements with special reference to anterior cruciate ligament surgery

The femoral intercondylar notch width was measured in 93 patients with chronic anterior cruciate ligament (ACL) insufficiency (Group 1), in 62 patients with an acute tear of the ACL (Group 2), and in 38 fresh anatomic specimen knees (Group 3). In six of the specimen knees, further anatomic studies of the intercondylar notch were performed after tissue removal. The average intercondylar distance was 16.1 mm in Group 1, 18.1 mm in Group 2, and 20.4 mm in Group 3. All differences were highly significant. The intercondylar notch was wider in the posterior part and had no crossing bony ridges but had generally concave walls, which provided a functional shelf for the ACL to insert on the lateral side. Significant osteophyte formation and stenosis of the anterior outlet of the intercondylar notch occur early in the ACL-deficient knee. A narrow anterior outlet of the intercondylar notch without osteophytes was also found in knees with an acute ACL rupture. At reconstruction of the ACL, notchplasty should be performed concomitantly.     

Tibial articular cartilage wear in varus osteoarthritic knees: correlation with anterior cruciate ligament integrity and severity of deformity

Tibial articular cartilage wear was assessed intraoperatively in 100 consecutive patients with varus osteoarthritis undergoing total knee arthroplasty. Severity of deformity on radiographs, integrity of the anterior cruciate ligament (ACL) at surgery, and body mass index were recorded. Posterior half of the medial tibial plateau was more commonly involved in knees with ACL deficiency; there was predominantly anteromedial involvement with an intact ACL. Varus deformity was significantly greater in knees with a deficient ACL than with an intact ACL. Severity of deformity did not alter the wear pattern, irrespective of the ACL integrity. The functional status of ACL in an osteoarthritic knee can be corroborated with the wear pattern on the tibial plateau articular cartilage.     

Anterior laxity and MR signals of the knee after exercise. A comparison of 9 normal knees and 6 anterior cruciate ligament reconstructed knees.

9 healthy volunteers and 6 patients with anterior cruciate ligament (ACL) grafts underwent anterior knee laxity measurements and MRI examinations of their knees before and after intensive physical exercise. In the volunteer group, anterior displacement of the knee at 89 and 133 newtons of loading, measured with a KT-2000 knee arthrometer, increased after exercise, compared to before it. In addition, anterior terminal stiffness decreased at 133 newtons of anterior loading. In the ACL group, anterior displacement at 89 and 133 newtons of loading also increased, while no difference was found in anterior terminal stiffness before versus after exercise. On MRI, the signal intensity of normal ACLs after exercise was higher than before it. In contrast, the signals from the grafts showed no differences before versus after exercise. Our findings suggest that the ACL grafts are biomechanically and biochemically different from normal ACLs, even 15 months after ACL reconstruction.     

A comparison of joint stability between anterior cruciate intact and deficient knees: a new canine model of anterior cruciate ligament disruption.

Transection of the canine anterior cruciate ligament (ACL) is a well-established osteoarthritis (OA) model. This study evaluated a new method of canine ACL disruption as well as canine knee joint laxity and joint capsule (JC) contribution to joint stability at two time points (16 and 26 weeks) after ACL disruption (n=5/time interval). Ten crossbreed hounds were evaluated with force plate gait analysis and radiographs at intervals up to 34 weeks after monopolar radiofrequency energy (MRFE) treatment of one randomly selected ACL. Each contralateral ACL was sham treated. The MRFE treated ACLs ruptured approximately eight weeks (mean 52.5 days, SEM+/-1.0, range 48-56 days) after treatment. Gait analysis and radiographic changes were consistent with established canine ACL transection models of OA. Anterior-posterior (AP) translation and medial-lateral (ML) rotation were measured in each knee at 30 degrees, 60 degrees, and 90 degrees of flexion with and then without JC with loads of 40 N in AP translation and 4 Nm in ML rotation. A statistically significant interaction in AP translation included JC by cruciate (P=0.02), and there was a trend for a cruciate by time (P=0.07) interaction. Significant interactions in ML rotational testing included the presence of joint capsule (P=0.0001) and angle by cruciate (P=0.0012). This study describes a model in which canine ACLs predictably rupture approximately eight weeks after arthroscopic surgery and details the contribution of JC to canine knee stability in both ACL intact and deficient knees. The model presented here avoids the introduction of potential surgical variables at the time of ACL rupture and may contribute to studies of OA pathogenesis and inhibition. This model may also be useful for insight into the pathologic changes that occur in the knee as the ACL undergoes degeneration prior to rupture.     

膝关节后内侧结构损伤合并单一交叉韧带断裂的早期治疗

目的 探讨膝关节后内侧结构损伤合并单一交叉韧带断裂进行早期手术的疗效.方法 2002年1月至2005年12月共治疗12例后内侧结构损伤合并单一交叉韧带断裂患者,其中10例合并前交叉韧带(ACL)断裂,2例合并后交叉韧带(PCL)断裂.交叉韧带损伤术前Lysholm评分为50～60分(平均56.7分).关节镜下重建交叉韧带,开放修复后内侧结构.8例采用自体半腱肌、股薄重建ACL(transfix术式),2例采用骨.髌腱.骨重建ACL.2例采用一端带骨块的异体跟腱蓖建PCL.后内侧结构损伤修复:8例采用星状钢板螺钉同定,2例采用GⅡ锚钉固定.1例采用自体半肌腱、股薄肌移植重建,1 例采用端对端缝合.结果 12例中除2例随访4个月后失访外,其余10例患者术后获平均12个月(6～18个月)随访.交叉韧带损伤重建后Lysholm评分为74～94分(平均81.2分).后内侧结构修复后10例膝伸屈范围正常,2例伸直受限5.外翻应力试验于O啦时,9例正常,2例弱阳性(+),1例阳性(++).结论 膝后内侧结构损伤合并单一交叉韧带断裂时,早期重建交叉韧带同时一期修复膝后内侧结构可以较好地恢复膝关节稳定性.     

Associated lateral/medial knee instability and its relevant factors in anterior cruciate ligament-injured knees

Background

Associations of lateral/medial knee instability with anterior cruciate ligament (ACL) injury have not been thoroughly investigated. The purposes of this study were to investigate whether lateral/medial knee instability is associated with ACL injury, and to clarify relevant factors for lateral/medial knee instability in ACL-injured knees.

Tibial subluxation in anterior cruciate ligament–deficient knees: Implications for tibial tunnel placement

Purpose: This study was performed to determine whether subtle anterior subluxation occurs in anterior cruciate ligament (ACL)–deficient knees with the knee in full extension. Type of study: Radiographic evaluation of tibial position in ACL-intact and ACL-deficient knees. Methods: Twenty-four subjects with arthroscopically documented ACL-deficient knees were compared with 20 subjects with arthroscopically documented ACL-intact knees. A previously reported method was used to evaluate the tibial position relative to the femur. Results: Measurements on standing lateral radiographs revealed asymptomatic but significant anterior subluxation of the tibia compared with the ACL-intact subjects. Conclusions: The possibility of anterior tibial subluxation with the knee in full extension should be taken into account when deciding on tibial tunnel placement or when evaluating for postoperative graft impingement by the intercondylar notch.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 17, No 9 (November-December), 2001: pp 960–962     

关节镜下同种异体跟腱骨一期重建膝关节前后交叉韧带

目的 评价关节镜下利用同种异体跟腱骨一期重建膝关节前后交叉韧带的疗效.方法 2000年7月至2005年2月收治15例患膝前后交叉韧带断裂但对侧膝关节完好者,在关节镜下先对合并存在的半月板损伤进行修复,然后使用2条同种异体跟腱骨一期重建前后交叉韧带.亚急性期或慢性期(>3周)重建12例,急性期(<3周)重建3例.手术前后采用IKDC和Lysholm评分系统对患膝关节功能进行评估,随访结果与对侧健康膝火节进行比较.结果 所有患者均获得36～40个月(平均38个月)随访.根据IKDC评分,术前所有患膝关节功能都严重异常,术后9例患膝功能改善为止常,5例接近正常,1例异常.Lysholm评分由术前平均(56±5)分改善为术后(90±4)分,差异有统汁学意义(t=15.660,P<0.05.结论同种异体跟腱骨可用于关节镜下重建膝关节前后交叉韧带,疗效满意.     

Relation of the fibular head sign to other signs of anterior cruciate ligament insufficiency. A follow-up letter to the editor.

The fibular head sign is a clinical finding that seems not to have been previously reported for the diagnosis of chronic anterior cruciate ligament insufficiency (ACLI) associated with lateral rotatory instability of the knee joint. The fibular head could be palpated as a prominent bony lump, felt subcutaneously in the posterior lateral corner of the popliteal fossa. In a prospective study of 20 patients with ACLI, the mean age of the patients (15 males, five females) at the time of assessment was 26 years (range, 18-57 years). The left knee was involved in 11 patients, the right knee in the remaining nine patients. All the patients sustained their knee ligament injury in sporting activities except one patient who was involved in a motor vehicular accident. The majority of the patients had instability-related symptoms for more than six months. After history taking, physical examination in the clinic, and examination under anesthesia, and arthroscopy in the operating room of all patients, it was determined that there were 13 ACL injuries, four posterior cruciate ligament (PCL) injuries, and three combined A/PCL injuries. All ACL injury patients had a prominent fibular head sign. Other associated signs included passive hyperextension of 10-20 degrees, and major anterolateral, and to a lesser degree a posterolateral, rotatory instability. The fibular head sign was negative in isolated posterior cruciate injuries and in combined A/PCL injuries.     

Simultaneous reconstruction of anterior cruciate ligament and posterior cruciate ligament by using allogeneic patellar tendon under arthroscopy

With fast development of arthroscopic surgery inChina, simple reconstruction of ACL (anteriorcrucial ligament) or PCL has been reported in number. However , the methods concerningsimultaneous reconstruction of ACL and PCL are rarelyreported. Simultaneous …     

Movement of the posterior cruciate ligament during knee flexion--MRI analysis.

The movement of the posterior cruciate ligament (PCL) during flexion of the living knee is unknown. The purpose of the present study was to analyze the movement of the PCL using magnetic resonance imaging (MRI). The posterior cruciate ligaments in 20 normal knees were visualized using MRI from extension to deep flexion. Sagittal inclination relative to the longitudinal axis of the tibia was measured and analyzed with reference to the patellar tendon (PT) and the anterior cruciate ligament (ACL). Although the PCL was slack in extension, it straightened with anterior inclination (24.1+/-5.1 degrees ) at 90 degrees flexion. At active maximum flexion (129.2+/-8.1 degrees ), the ligament was almost parallel (3.9+/-7.4 degrees inclination) to the longitudinal axis of the tibia. At passive maximum flexion (158.8+/-5.8 degrees ), the inclination was reversed anteroposteriorly, measuring -23.0+/-6.7 degrees . The PCL and PT moved in a corresponding manner within 20 degrees of discrepancy. The results of this in vivo study of the PCL have clinical relevance to conservative therapy for PCL knee injuries. The results of this study could also be useful in PCL reconstruction surgery to determine the optimum graft position to allow maximum postoperative motion.