Mucoid degeneration of the anterior cruciate ligament with erosion of the lateral femoral condyle

We report a case of a mucoid degeneration of the anterior cruciate ligament (ACL) that produced osseous erosion of the medial aspect of the lateral femoral condyle. The MRI findings and differential diagnosis are discussed.     

Mucoid degeneration of the anterior cruciate ligament

Mucoid degeneration of the anterior cruciate ligament (ACL) is a rare cause of knee pain. We report a case of a patient with mucoid degeneration of the ACL, presenting with posterior knee pain and no history of a major knee trauma. On clinical examination, the active range of motion showed a flexion deficit. The posterior knee pain was induced by passive hyperflexion of the knee. There was no evidence of ligamentary instability. MRI showed a diffuse thickening of the ACL with a nodular mass on the femoral insertion occupying the intercondylar notch, with increased signal intensity on both T1- and T2-weighted images. Arthroscopic evaluation showed a diffuse hypertrophy of the ACL, throughout the entire length of the posterolateral bundle (PLB). A yellowish homogenous mass on the femoral insertion of the ACL impinged on the posterior cruciate ligament (PCL) in flexion and occupied the entire intercondylar notch. We performed an arthroscopic debridement of the hypertrophied tissues as precisely as possible. This resulted in a nearly complete removal of the PLB and immediate relief of symptoms. Examination of knee stability after debridement showed a stable ACL. Arthroscopic debridement of the mucoid degeneration of the ACL proved to be a safe and effective method, without causing ligamentary instability in daily activities.     

Mucoid degeneration of the anterior cruciate ligament: magnetic resonance imaging findings of an underdiagnosed entity

Although imaging and clinical criteria are already established for the diagnosis of mucoid degeneration of the anterior cruciate ligament (ACL), many radiologists remain unaware of their existence. Once regarded as a rare occurrence, it has been recently suggested that its incidence is in fact very much higher than previously thought, and that it is probably underdiagnosed or misdiagnosed as partial ruptures of the ACL or as cystic ganglia. In this review, the authors revisit the literature concerning this subject and present their personal experience with it, stressing the paramount importance of magnetic resonance imaging and correlation with clinical data for a correct diagnosis.     

Relationship between mucoid hypertrophy of the anterior cruciate ligament (ACL) and morphologic change of the intercondylar notch: MRI and arthroscopy correlation

OBJECTIVE: The purpose of this study was to evaluate the relationship between mucoid hypertrophy of the anterior cruciate ligament (ACL) and morphologic change of the intercondylar notch. MATERIALS AND METHODS: We retrospectively reviewed the 105 patients with knee magnetic resonance imaging (MRI) with or without knee arthroscopy [group 1: patients with arthroscopic notchplasty (N = 47), group 2: knee arthroscopy demonstrating intact ACL (N = 33), and group 3: patients with normal knee MRI but no arthroscopy (N = 25)]. Groups 2 and 3 served as an arthroscopic and MR control group, respectively. Two musculoskeletal radiologists reviewed all MR examinations. The intercondylar notch width, notch index (width of intercondylar notch/width of femoral condyle), transverse notch angle (TNA), sagittal notch angle (SNA), and notch area were recorded on axial and sagittal MR images at the midpoint of Blumensaat's line which was identified on sagittal images. The diameter of the ACL was recorded on coronal MR images at the posterior end of Blumensaat's line. RESULTS: The mean values of the intercondylar notch width, notch index, TNA, SNA, notch area, and ACL diameter for the three groups were 16.0 mm/0.2/50.3 degrees /36.5 degrees /249.0 mm(2)/7.7 mm (group 1); 19.3 mm/0.3/52.9 degrees /40.2 degrees /323.4 mm(2)/4.8 mm (group 2); and 20.3 mm/0.3/51.4 degrees /39.1 degrees /350.8 mm(2)/4.5 mm (group 3). The intercondylar notch width, notch index, SNA, and notch area were smaller, and ACL diameter was thicker in group 1 compared with the other groups (p < 0.05). CONCLUSION: Patients with mucoid ACL hypertrophy show a narrower notch, a steeper notch angle, and a smaller notch area than control groups.     

Mucoid degeneration of the anterior cruciate ligament mistaken for ligamentous tears

Objective. To describe the MR features of mucoid degeneration of the anterior cruciate ligament (ACL) in a series of patients with MRI findings that were mistaken for tears in the majority of cases but who were found to have an intact ligament at arthroscopy. We will suggest a pathologic entity corresponding to this finding and describe some characteristic features that can be used to identify this entity on MRI. Design. A retrospective analysis of 10 MRI examinations of the knee was performed after arthroscopic evaluation. Prearthroscopic MRI findings had been interpreted as a tear in six patients prospectively and in the remaining four the diagnosis of mucoid degeneration was suggested and ultimately proven. All patients had an intact ACL by preoperative clinical examination, examination under anesthesia, and at arthroscopy. Results. MRI examinations demonstrated an ill-defined ACL, greater in girth than the normal ligament and characterized by increased signal on all sequences. The high-signal ligament was oriented in the normal direction of the ACL. The overall appearance of the ligament was retrospectively described as like a celery stalk. Arthroscopy demonstrated mechanically intact ligaments with a normal to expanded external appearance. Probing of three of the ligaments caused a material to be expressed and pathologic evaluation resulted in the diagnosis of cystic, mucoid degeneration. Conclusion. Mucoid degeneration and an intact ACL can be suspected when an apparently thickened and ill-defined ligament with increased signal intensity on all sequences is identified in a patient with a clinically intact ligament. Received: 10 April 2000 Revision requested: 18 July 2000 Revision received: 13 November 2000 Accepted: 27 November 2000     

Isokinetic muscle strength after anterior cruciate ligament reconstruction

The purpose of the present study was to investigate the isokinetic muscle strength 6 months after reconstruction of the anterior cruciate ligament (ACL). In order to recommend full-load come-back in sport, sufficient muscle strength may be important. Ninety female elite team handball players (mean 24.1 years) were postoperatively tested with Biodex. The operated limb was compared with the contralateral limb: 82.2% had a hamstring strength of a minimum of 49.6 Nm, corresponding to at least 90% of the non-operated limb, while only 12.2% fulfilled the recommended strength of 117.7 Nm for quadriceps femoris. Patients over 26 years showed significantly lower muscle strength in the operated limb than their younger counterparts. Increased focus on quadriceps femoris muscle strength during rehabilitation may improve the knee function faster after ACL reconstruction.     

MRI of normal anterior cruciate ligament (ACL) and reconstructed ACL: comparison of when the knee is extended with when the knee is flexed

The purpose of this study was to evaluate, using MRI, the morphology of normal anterior cruciate ligament (ACL) and ACL grafts when the knee was extended compared with when the knee was flexed. Eighteen normal controls and 22 ACL graft patients were studied. Spin-echo (SE) T1-weighted images (TR 330 ms/TE 15 ms, NEX 1) were obtained with a slice thickness of 3 mm. Oblique sagittal images parallel to the ACL were obtained at various flexed angles of the knee joint. In 12 of the 18 normal controls the ACL appeared convex toward the posterior side when the knee was extended and gradually became straight when the knee was flexed. In 15 of the 22 ACL graft patients the grafts appeared straight when the knee was extended and became convex toward the anterior side when the knee was flexed. It is concluded that the morphological changes seen on MR images of ACL grafts from when the knee is extended to when the knee is flexed are different from those in the normal ACL. Received: 11 January 1996; Accepted: 27 December 1996     

Composite Gore-Tex and autogenoussemitendinosus anterior cruciate ligament reconstruction: Long-term results and historical review

Over the past decade, anterior cruciate ligament reconstruction has evolved into a reproducible procedure withpredictably good results. However, there are still some failures. Some of these failures have obvious mechanical or technical etiologies. For others, the etiology remains unclear. This article examines an explanation for some of these failures and presents a reasonable revision technique to avoid a recurrent failure.     

Comparison of functional outcome after anterior cruciate ligament reconstruction resulting in low, normal and increased laxity

The aim of the study was to analyse and compare the results after arthroscopic anterior cruciate ligament (ACL) reconstruction using patellar tendon autografts in three groups of patients. The groups were determined by knee laxity as measured with the KT-1000 arthrometer at the follow-up two to five years after the reconstruction. Group A (n=15) had an anterior side-to-side laxity difference of <-3 mm (i.e. the reconstructed knee was less lax than the contralateral non-injured knee), Group B (n=376) had a difference of > or = -1, but < or = +2 mm and Group C (n=38) had a difference of > or g=6 mm. All the patients had a normal contralateral knee. In Group A, 7/15 (47%) patients and, in Group B, 82/375 (22%) patients had an extension deficit of > or =5 degrees (P=0.052). The corresponding values in terms of flexion deficit were 8/15 (53%) and 99/375 (26%) respectively (P=0.04) (one missing value in Group B). In Group C, 14/38 (37%) had an extension deficit (P=0.04; Group B vs Group C). Group C displayed worse results than Group B in terms of the Lysholm score and the one-leg-hop test (P=0.001 and P=0.011 respectively). The corresponding comparison between Group A and Group B revealed no significant differences. We conclude that a considerable number of patients showed persisting deficits in range of motion (ROM) after an ACL reconstruction. No major differences were found if they were analysed in subgroups with decreased, near normal or with increased knee laxity. The worst residual functional impairment, as measured with the Lysholm score and one-leg-hop test, was found in the group with increased knee laxity and most ROM deficits in the knees with decreased laxity.     

Proprioceptive comparison of allograft and autograft anterior cruciate ligament reconstructions

The aim of this study is to search if there is any proprioceptive difference between auto and allograft anterior cruciate ligament (ACL) reconstructions, and also to determine if there is any relationship between instrumented anterior knee laxity and proprioception after an ACL reconstruction. The following four groups were constituted for this purpose: group I, control group; group II, autograft reconstructions; group III, allograft reconstructions and group IV, people with injured ACLs. Each group consisted of 20 patients/volunteers. Two subgroups were constituted according to the findings of KT-1000 laxity testing in group II and III; patients/volunteers found to have a laxity of 3 mm or less were enroled in the normal subgroup and those with a laxity of more than 3 mm were enroled in the lax subgroup. Two proprioceptive tests were used: threshold to detect passive motion (TDPM) and joint position sense (JPS) by using Cybex Norm dynamometer. Patients underwent ten tests and the discrepancy in degrees was averaged for ten trials. Comparisons were made to evaluate the proprioceptive differences between groups/subgroups; ANOVA and t test was used for comparisons where appropriate, and the significance was set at P < 0.05. There was a significant difference in degrees between patients with injured ACLs and the other three groups in TDPM evaluations (injured: 1.93° vs. control: 1.03°, autograft: 1.01°, allograft: 0.96°; P < 0.001). Auto and allograft reconstructions were not different from each other and controls. Allo and autograft ACL reconstructions are not different from each other according to proprioceptive measurements. Also, proprioception is not correlated to postoperative anterior knee laxity; many variables involve joint proprioception and mostly the anterior knee laxity may not be the sole determining element, and a lax ACL still may fulfill some of its afferent arc functions as long as it bridges the femur and tibia.     

Tunnel placement in anterior cruciate ligament reconstruction: MRI analysis as an important factor in the radiological report

 Objective. Correct placement of tunnels for anterior cruciate ligament (ACL) reconstruction is of prime importance for the clinical outcome of the patient. In this study, the possibility of using MRI to document tunnel placement and provide a more comprehensive report following ACL reconstruction was explored at no additional cost in patients scheduled for routine knee MRI. Design and patients. One year after ACL reconstruction, 45 patients underwent clinical examination (IKCD score), radiographic examination, and MRI using a 1.5-T unit. Results. Twenty patients with good tibial and femoral attachment results were found at clinical examination to have a stable knee joint with a full range of motion. In 25 patients with suboptimal placements, examination showed either a stable knee with a decreased range of motion or instability with a normal range of motion. Conclusion. Patients’ clinical outcome, and the radiographic and MRI findings, correlated closely with the quality of operative tunnel placement. A record of this finding is important for completeness of the radiological report. Furthermore the MRI findings can be used to improve the surgical quality of tunnel placement. Because tunnel placement can be shown adequately with radiography, however, MRI cannot be justified for this reason alone, so such assessment is advised only when MRI is needed to show all postoperative features.     

MRI of anterior cruciate ligament repair with patellar and hamstring tendon autografts

Objective. Several MRI sequences were used to evaluate the 2-year postoperative appearance of asymptomatic knee with a torn anterior cruciate ligament (ACL) reconstructed with bone–patellar tendon–bone (BTB) and semitendinosus and gracilis (STG) tendon autografts. Design and patients. Two groups with successful repair of ACL tear with BTB (n=10) or STG (n=10) autografts were imaged at 1.5 T with sagittal and oblique coronal proton density-, T2-weighted and sagittal STIR sequences and plain and contrast-enhanced oblique coronal T1-weighted sequences. The appearance of the graft and periligamentous tissues was evaluated. Results. In all 20 cases, the ACL graft showed homogeneous, low signal intensity with periligamentous streaks of intermediate signal intensity on T2-weighted images. In 10 cases, localised areas of intermediate signal intensity were seen in the intra-articular segment of the graft on proton density- and T1-weighted images. The graft itself did not show enhancement in either of the two groups, but mild to moderate periligamentous enhancement was detected in 10 cases. Conclusion. The MRI appearance of ACL autograft is variable on proton density- and T1-weighted images. Periligamentous tissue showing contrast enhancement is a typical MRI finding after clinically successful ACL reconstruction. Received: 22 February 2000 Revision requested: 27 June 2000 Revision received: 21 August 2000 Accepted: 23 August 2000     

MRI assessment of tibial tunnel and its relation to complication following arthroscopic reconstruction of anterior cruciate ligament

Purpose

To assess the role of MRI in evaluation of tibial tunnel and correlate findings with the rate of post anterior cruciate ligament (ACL) repair complication.

Patients and methods

A prospective study recruited 34 patients, their ages ranged between 18 and 38 years after arthroscopic repair of ACL. All patients were referred from the orthopedic department between July 2012 and July 2013 with symptoms and signs suspicious of complications. MRI knee was performed for all patients after meeting inclusion criteria.

Results

MRI was positive in 24 (70.6%) out of 34 patients. Graft impingement was the most frequently encountered complication representing 13/24 (54.1%). Graft disruption was encountered in 4/24 (16.7%). Graft stretching, arthrofibrosis and ganglion cyst were seen in two patients for each (8.3%). One patient had abnormal graft signal without disruption (4.1%). The remaining 12/34 (35.3%) patients had negative MRI with intact graft. Tunnel mal position was seen in 18/24 (75%) with positive post ACL reconstruction complications.

Conclusion

Anterior cruciate ligament reconstruction is one of the most commonly performed sports medicine procedures. MRI proved as an accurate method for post arthroscopic reconstruction evaluation that can help predict post ACL reconstruction complication.     

Simultaneous bilateral anterior cruciate ligament tears in a female beginner skier

We present a case of simultaneous bilateral ACL tears in a woman injured while skiing for the first time. We discuss the role of intercondylar notch stenosis as a high-risk factor for tearing the ACL, the injury mechanism, prevention measures, and the therapeutic strategy. Received: 10 January 2000 Accepted: 10 April 2000     

Revision of failed gore-tex anterior cruciate ligament reconstruction

The Gore-Tex synthetic knee ligament was widely used in the early 1980s because of encouraging early results. However, the long-term failure rate is unfavorable. Gore-Tex failures are divided into four categories: effusion, graft rupture, loosening/ osteolysis, and infection. Revision surgery is challenging and requires a systematic approach to achieve optimal results.     

前交叉韧带断裂的MRI征象研究

目的 研究前交叉韧带(ACL)断裂的MRI表现,探讨其直接征象和间接征象的产生机制及诊断价值.方法 本组男37例,女3例;年龄16～49岁,平均33岁.急性期断裂28例,慢性期断裂12例,均经关节镜检查和手术证实.采用1.5 T西门子MRI扫描仪,SE或TSE序列T1、12、质子压脂、medic和横断位、矢状位、冠状位多方位成像.组织3名高年资医师进行回顾分析,对ACL断裂的MRI直接征象和间接征象进行统计分析.结果 ACL断裂4|D例中完全性断裂35例,部分断裂5例.急性期断裂的28例直接征象分别为信号中断或不连续24例(86%),信号不均匀18例(64%),韧带肿胀增厚10例(36%);而慢性期断裂的12例分别韧带增厚11例(92%),信号中断或不连续9例(75%),信号不均匀7例(58%),其中韧带增厚征象主要见于慢性期的ACL断裂(P＜0.01).完全性断裂的35例中,28例(80%)发生在中段,上端、下端发生率低;5例部分断裂均发生在前内侧束.ACL断裂的间接征象中,后交叉韧带(PCL)"7"字变形34例(85%);半月板外露26例,其中外侧半月板外露16例(62%);骨损伤15例,其中胫骨撕裂骨折8例(53%);关节间隙增宽9例,其中78%属于慢性断裂;胫骨前移23例(57%).本组40例中,术前正确诊断37例,正确率为92%;3例部分断裂术前未能诊断,漏诊率为8%.结论 根据ACL断裂的直接征象和间接征象,结合外伤史,术前诊断比较容易.     

One-stage bilateral anterior cruciate ligament reconstruction with use of hamstring tendon autografts: a case report

This article presents an unusual problem of a patient with chronic bilateral ACL-deficient knees and constitutionally very thin patellar tendons. Author decided to perform one-stage bilateral ACL reconstructions using hamstring tendon autografts so as not to weaken his quadriceps muscles by compromising his extensor mechanism.     

高频超声测量前交叉韧带厚径与前交叉韧带损伤的相关性

 目的 探讨应用高频超声测量前交叉韧带(anterior cruciate ligament, ACL)厚径与ACL损伤的相关性。方法 选择单侧非接触性ACL损伤现役男性军人患者30例为ACL损伤组,另选择现役男性健康军人30名为对照组。应用高频超声测量ACL胫骨止点端厚径,ACL损伤组检查健侧ACL,对照组检查双侧ACL。对比分析对照组左侧、右侧ACL厚径,再对比分析ACL损伤组健侧、对照组ACL厚径。结果 对照组左侧、右侧ACL厚径分别为(8.11±0.64)mm、(8.03±0.61)mm,差异无统计学意义(P<0.05)。ACL损伤组健侧ACL厚径为(6.25±0.37)mm,小于对照组(8.07±0.61) mm,差异有统计学意义(P<0.05)。结论 ACL厚径小会增加ACL损伤的风险,高频超声测量ACL厚径可作为一项评估ACL损伤风险的筛查指标。     

Oblique sagittal view of the anterior cruciate ligament: comparison of coronal vs. axial planes as localizing sequences

The purpose of this study was to determine whether oblique sagittal T2-weighted images of the anterior cruciate ligament (ACL) are better prescribed off axial or coronal localizing images. Thirty-one patients underwent two sets of oblique sagittal T2-weighted fast spin-echo sequences to evaluate the ACL. One oblique was prescribed from a coronal localizing sequence, while the other was prescribed off an axial series. Objective (average number of images to demonstrate ACL) and subjective (radiologist's confidence level) evaluations of both sequences were performed independently of the other and then comparatively by two radiologists. The coronally prescribed sagittal oblique was subjectively preferred in 18 patients, the axially prescribed oblique was preferred in one patient, and both sequences were felt to be equivalent in 12 patients. In 13 intact ligaments, the average number of images clearly demonstrating the entire length of the ACL was 1.77 on the coronally prescribed sequence and 1.31 on the axially prescribed images. Oblique sagittal images prescribed off a coronal localizer are both subjectively and objectively more effective than axially prescribed sagittal obliques in evaluating the ACL.     

Objective factors affecting overall subjective evaluation of recovery after anterior cruciate ligament reconstruction

Muneta T, Sekiya I, Ogiuchi T, Yagishita K, Yamamoto H, Shinomiya K. Objective factors affecting overall subjective evaluation of recovery after anterior cruciate ligament reconstruction. The goal of this prospective study was to determine how objective measurements affect the overall subjective evaluation of recovery after anterior cruciate ligament (ACL) reconstruction and to evaluate the effects of graft material, residual instability and sporting activity on patient satisfaction. Ninety-seven patients with unilateral ACL injuries whose ACL was reconstructed using either a multi-strand semitendinosus (ST) graft or a central-third bone-patellar tendon-bone (BTB) graft were followed for an average of 30 months. An “overall subjective recovery score” was derived from the patients' evaluation of function of the operated knee as a percentage of the unoperated knee. The mean overall subjective recovery score at follow-up was 80% (range, 20% to 100%). This study strongly suggested that integrity of the knee extension mechanism, that is, good recovery of knee extension strength with achievement of full extension and no problems in the patellofemoral joint, is the most important factor in patient satisfaction after ACL reconstruction.