Anterior medial meniscus detachment and anterior cruciate ligament tear

This paper reports on two cases of medial meniscus injury involving detachment of the anterior horn together with a coronary ligament tear. Both cases were associated with tearing of the anterior cruciate ligament. The meniscal injuries observed were similar to those reported in the literature prior to the development of arthroscopic surgery. Variant attachments of the anterior horn of the medial meniscus are thought to have contributed to this injury.     

Partial tear of the anterior cruciate ligament of the knee: injury patterns on MR imaging

Purpose  

To describe rupture patterns of partial anterior cruciate ligament (ACL) tears on magnetic resonance (MR) imaging.     

Lateral meniscus root tear and meniscus extrusion with anterior cruciate ligament tear

PURPOSE: To retrospectively determine the prevalence of posterior lateral meniscus root tears (LMRTs), as depicted on magnetic resonance (MR) images, in patients with an anterior cruciate ligament (ACL) tear and to investigate the association of LMRTs with lateral meniscus extrusion and other ligament injuries. MATERIALS AND METHODS: Institutional review board approval was obtained; informed consent was not required. This study was HIPAA compliant. MR images were obtained in 174 male and 119 female patients (mean age, 37 years; age range, 16-87 years) and retrospectively reviewed for LMRT, medial meniscus root tear (MMRT), nonroot meniscus tear, meniscus extrusion, and presence of meniscofemoral ligaments (MFLs). The chi2 and unpaired Student t tests were performed. RESULTS: In 33 patients, 34 meniscus root tears were identified. An LMRT was present in 26 (9.8%) of 264 patients, and an MMRT was present in eight (3.0%) (P=.008). Lateral meniscus extrusion was present in six (23%) of 26 LMRTs and five (2.2%) of 231 patients with normal meniscus roots (P<.001). Complex or deep radial tears were found in three of five cases of lateral meniscus extrusion and normal root. The MFL was not observed in five (19%) of 26 studies of an LMRT. Among these 26 studies of an LMRT, lateral meniscus extrusion was identified in three (14%) of 21 cases in which the MFL was intact and in three (60%) of five cases in which the MFL was not identified (P<.03). Prevalence of an extruded meniscus was seven (88%) of eight for an MMRT and six (23%) of 26 for an LMRT (P=.001). CONCLUSION: Prevalence of LMRTs is greater than that of MMRTs in patients with an ACL tear. LMRTs and complex and radial tears are associated with lateral meniscus extrusion; an absent MFL is more prevalent in patients with LMRTs and when the meniscus is extruded.     

Followup of the acute nonoperated isolated anterior cruciate ligament tear

This report is an attempt to analyze what happens to an isolated ACL tear that is treated nonoperatively. The results of 40 patients treated initially by nonoperative means for this injury and followed an average of 4 years are reported. A very small percentage of these patients had associated meniscal pathology. Secondary reconstructive surgery was necessary in 12 patients (30%). Primary meniscal tears were present in 4 of 25 knees (16%) and secondary meniscal tears occurred in an additional four of the patients. Giving way was a problem for 36 (86%) of the nonoperated patients, but pain and swelling were not significant problems for most. Full return to unlimited athletic activities was possible for only four (14%) of the patients. Objective signs of ACL insufficiency could be demonstrated on all patients upon clinical examination at followup. Overall grading of the knees revealed 87.5% fair or poor results.     

Knee laxity after complete anterior cruciate ligament tear: a prospective study over 15 years

There is limited knowledge of knee laxity in the long term after a complete anterior cruciate ligament (ACL) tear treated without ACL reconstruction. The aim of this study was (1) to describe the clinical course of knee laxity after a complete ACL tear over 15 years, and (2) to study the association between knee laxity and meniscal injuries and the development of knee osteoarthritis (OA). We studied 100 consecutive subjects [mean (SD) age 26 (8) years] presenting with acute ACL injury prospectively. The initial treatment in all subjects was knee rehabilitation without reconstructive surgery. The subjects were examined with Lachman's and pivot‐shift tests at baseline, 6 weeks, 3 months, 1 year, 3 years and 15 years after the injury. Sagittal knee laxity was also evaluated with the KT‐1000 arthrometer at the 15‐year follow‐up. During follow‐up, 22 subjects were ACL reconstructed due to unacceptable knee instability. There was only a mild remaining knee laxity [median Lachman grade and pivot‐shift test value of 1 on a 4‐grade scale (0–3)] after 15 years in subjects treated without primary ACL reconstruction. Knees with higher anterior sagittal knee laxity 3 months after the injury had a worse long‐term outcome with respect to meniscal injuries and knee OA development.     

Kinematics of active knee extension after tear of the anterior cruciate ligament

Three-dimensional movements of the knees in 13 patients with unilateral old tears of ACLs were studied during extension. Roentgen stereophotogrammetric methods were used to measure tibial movements in the injured and the intact knees. Reduced internal rotation and adduction were recorded at the end of extension on both sides. The injured knees displayed increased anterior and distal displacements of the tibial intercondylar eminence. Abnormal tibial displacements in our patients indicate that the absence of the ACL is not completely compensated for during active extension past 30 degrees; close to the extended position, the tibial movements tend to normalize.     

Partial tears of the anterior cruciate ligament in children and adolescents

BACKGROUND: The functional outcome after partial anterior cruciate ligament tears in children and adolescents treated without reconstruction has not been established. HYPOTHESIS: Nonreconstructive management of partial anterior cruciate ligament tears can be effective in certain pediatric patients. STUDY DESIGN: Prospective cohort study. METHODS: We studied 45 skeletally mature and immature patients 17 years of age or less who had an acute hemarthrosis, magnetic resonance imaging signal changes, grade A or B Lachman and pivot shift result, and an arthroscopically documented partial anterior cruciate ligament tears. All patients were treated without reconstruction, underwent a structured rehabilitation program, and were followed up for a minimum of 2 years. RESULTS: Fourteen patients (31%) underwent subsequent reconstruction. Significant associations with subsequent reconstruction included tears that were greater than 50%, predominantly posterolateral tears, a grade B pivot shift test result, and older chronologic and skeletal age. Among patients who did not require reconstruction, those with tears that were greater than 50% or predominantly posterolateral had significantly lower Lysholm, satisfaction, and Cincinnati Knee Scale scores. CONCLUSIONS: Nonreconstructive management is recommended for partial anterior cruciate ligament tears in children and adolescents 14 years of skeletal age or younger with normal or near-normal Lachman and pivot shift results. Reconstruction is recommended in older athletes or in those with greater than 50% or predominantly posterolateral tears.     

关节镜下异体骨-髌腱-骨纤维束重建治疗前交叉韧带部分损伤

目的 探讨异体骨-髌腱-骨纤维束（B-PT-B）重建前交叉韧带（ACL）全部纤维束和部分纤维束的早期疗效。方法在187例采用B-PT-B术式重建ACL的患者中，获得随访的ACL部分束损者共25例，其中采用全部纤维束重建的患者6例，部分纤维束重建19例。术后行X线和KT-1000检查，并按照IKDC、Lysholm、Irgang、Larson评分进行疗效评价。结果 所有患者随访时移植物位置良好，KT-1000检查双侧膝关节前向松弛度差值〈3mm。部分束重建组与全部束重建组各评分系统和分项评分系统无显著性差异。结论 异体B-PT-B重建治疗ACL部分损伤可以取得良好的临床疗效，与ACL全部束重建术相比综合评定无明显差异。     

Eighteen- to twenty-four-year follow-up after complete rupture of the anterior cruciate ligament

A unilateral, complete rupture of the anterior cruciate ligament was diagnosed in 60 consecutive patients by arthroscopy within 1 week of trauma. Most ruptured ligaments were treated by acute nonaugmented repair immediately after the arthroscopy. Fifty-five and 56 patients were reevaluated after 12 years and 20 years, respectively. Twenty-five patients (45%) had at least one reoperation during the follow-up period of 20 years, primarily for meniscal problems. Seven patients (13%) had repeat anterior cruciate ligament surgery. The overall Lysholm knee function score remained at a median of 90 points from 12 to 20 years, but patients had decreased their sporting activities from team sports at full rehabilitation to physical fitness activities at the late follow-up. Patients who had repeat surgery had a worse knee function score, were less satisfied with their knees, and also had to change activities and change work more often than patients without reoperation. The majority of patients had, at both follow-up periods, unstable knees. At 20 years, weightbearing radiographs showed slight-to-moderate changes equivalent to osteoarthrosis in 84% (47) of patients and a 32% increase in osteoarthrosis since the 12-year evaluation.     

Correlation of anthropometric measurements, strength, anterior cruciate ligament size, and intercondylar notch characteristics to sex differences in anterior cruciate ligament tear rates

We performed a prospective study based on the hypothesis that physiologic differences exist between men and women in strength after adjustments for body weight; that the size of the anterior cruciate ligament is proportionate to the strength of its antagonists, the quadriceps muscles; and that women have a relatively small anterior cruciate ligament, thus predisposing them to a disproportionate number of anterior cruciate ligament injuries. One hundred matched high school basketball players, 50 male and 50 female, were evaluated with anthropometric measurements, body fat analysis, muscle strength evaluation, and magnetic resonance imaging measurements of the intercondylar notch and cross-sectional area of the anterior cruciate ligament at the outlet. The male players were taller and heavier than their female counterparts, although they had 11% less body fat. Male players had statistically greater quadriceps and hamstring muscle strength than female players, even when adjustments were made for body weight. With adjustments for body weight, the size of the anterior cruciate ligament in girls was found to be statistically smaller than in boys. There was no statistically significant difference in the notch width index between the sexes. The study data support our hypothesis that sex differences in anterior cruciate ligament tear rates are caused primarily by several interrelated intrinsic factors. Most importantly, stiffness and muscular strength increase stress on the anterior cruciate ligament in female athletes. The anterior cruciate ligament, when adjustments have been made for body weight, is smaller in female athletes, and therefore, probably does not compensate for the lack of stiffness and strength.     

Anterolateral ligament injuries in knees with an anterior cruciate ligament tear: Contribution of ultrasonography and MRI

Objectives

To describe the pathological appearance of the anterolateral ligament (ALL) on US and MRI in knees with an anterior cruciate ligament (ACL) tear.

Methods

This prospective study included 30 patients who had a suspected acute ACL tear. Their injured and contralateral knees were evaluated with radiography, US and MRI. Two radiologists evaluated the ALL on the MRI and US examinations. Agreement between these examiners’ findings was evaluated with Cohen’s kappa.

Results

On US examination, the ALL was found to be injured in 63% of cases (19/30; k = 0.93). The enthesis was found to be torn in 50% of cases (15/30; k = 1), with the tear located at the tibial attachment in all instances. On the MRI exam, the ALL was found to be injured in 53% of cases (16/30; k = 0.93). The enthesis was found to be torn in 13% of cases (4/30; k = 0.76), with the tear located at the tibial attachment in all instances (k = 0.93).

Conclusion

ALL injuries that occur with ACL tears are located at the tibial enthesis. They are often associated with bone avulsion at the enthesis and are better viewed on US.

Key Points

? ALL injuries often occur in combination with ACL tears. ? ALL injuries can be assessed with ultrasonography and MRI. ? ALL injuries associated with ACL tears are located at the tibial enthesis.

     

Anatomy of the anterior cruciate ligament

The anterior cruciate ligament (ACL) is a band of dense connective tissue which courses from the femur to the tibia. The ACL is a key structure in the knee joint, as it resists anterior tibial translation and rotational loads. When the knee is extended, the ACL has a mean length of 32 mm and a width of 7–12 mm. There are two components of the ACL, the anteromedial bundle (AMB) and the posterolateral bundle (PLB). They are not isometric with the main change being lengthening of the AMB and shortening of the PLB during flexion. The ACL has a microstructure of collagen bundles of multiple types (mostly type I) and a matrix made of a network of proteins, glycoproteins, elastic systems, and glycosaminoglycans with multiple functional interactions. The complex ultrastructural organization and abundant elastic system of the ACL allow it to withstand multiaxial stresses and varying tensile strains. The ACL is innervated by posterior articular branches of the tibial nerve and is vascularized by branches of the middle genicular artery.     

The anterior cruciate ligament tear rate varies by race in professional Women's basketball

BACKGROUND: Female basketball players are more likely to tear their anterior cruciate ligament than are their male counterparts. Many causes are postulated for the difference observed in the rate of anterior cruciate ligament tears between genders. However, little is known about the differences in tears within gender. HYPOTHESIS: The rate of anterior cruciate ligament tears is different in White European American female basketball players and non-White European American players. STUDY DESIGN: Cohort study (Prevalence); Level of evidence, 2. METHODS: The authors investigated the differences in anterior cruciate ligament tears by risk exposure in women of different racial or ethnic backgrounds playing in the Women's National Basketball Association for the 1999 through 2003 seasons. Using the injury surveillance data from the Women's National Basketball Association, the authors compared anterior cruciate ligament injuries in White European American and non-White European American players to determine differences in the rate of anterior cruciate ligament tears between racial groups. RESULTS: The anterior cruciate ligament tear rate for White European American players was 0.45 per 1000 athletic exposures, whereas for non-White European American players (black or African American, Hispanic, and Asian players) the rate was 0.07. The odds ratio of anterior cruciate ligament tears in White European American versus non-White European American players was 6.55 (95% confidence interval, 1.35-31.73). CONCLUSION: Our retrospective study shows that the anterior cruciate ligament tear rate for White European American players was 0.45 per 1000 athletic exposures, whereas tear rates in the Women's National Basketball Association vary by racial group, with White European American players having more than 6 times the anterior cruciate ligament tear rate of other ethnic groups combined. Further prospective studies of athletes are needed to validate this finding and shed light on possible reasons.     

双前交叉韧带征:外侧半月板桶柄状撕裂MR征象

目的:报道外侧半月板桶柄状撕裂的一个MR征象-双"ACL"征.方法:回顾性分析7例经关节镜证实外侧半月板桶柄状撕裂的MR表现.结果:7例患者中,4例MR机检查矢状位T2W图像上观察到ACL后方与ACL平行的条状低信号影,呈现双"ACL"征.结论:双"ACL"征可以提示ACL桶柄状撕裂可能,其临床价值有待于进一步研究.     

Quantitative knee cartilage measurement at MR imaging of patients with anterior cruciate ligament tear

In previous studies, numerous approaches were proposed that assess knee cartilage volume quantitatively using 3D magnetic resonance (MR) imaging. However, the clinical use of these approaches is limited because 3D MR is prone to metal artifacts in postoperative cases. Our purpose in this study was to validate a method for knee cartilage volume quantification using conventional MR imaging in patients who underwent anterior cruciate ligament (ACL) reconstruction surgery. The study included 16 patients who underwent MR imaging before and 1 year after ACL reconstruction surgery. Knee cartilage volumes were measured by our computer-based method with the use of T1-weighted sagittal images. We classified the cartilage into eight regions and made comparisons between preoperative and postoperative cartilage volumes in each region. There was a significant difference between preoperative and postoperative cartilage volumes with regard to medial posterior weight-bearing, medial posterior, lateral posterior weight-bearing, and lateral posterior portions (p = 0.006, 0.023, 0.017 and 0.002, respectively). These results were consistent with the previous studies showing that knee cartilage loss occurs frequently in these portions due to an anterior subluxation of the tibia accompanied by ACL tear. With our method, knee cartilage volumes could be measured quantitatively with conventional MR imaging in patients who underwent ACL reconstruction surgery.     

Deep lateral femoral sulcus: study of 124 patients with anterior cruciate ligament tear

Abnormal deepening of the lateral femoral sulcus has been proposed as a potential indirect sign allowing the diagnosis of an anterior cruciate ligament (ACL) tear on conventional lateral knee radiographs. We studied a large group of patients with proven ACL tears during the acute injury and at 5-year follow-up to determine (a) the normal range of the depth of this sulcus and (b) the sensitivity, specificity, and positive predictive value of a deepened lateral sulcus. One hundred fifty patients with suspected ACL tears after sustaining unilateral injuries to their knees were referred to a specialty clinic for further evaluation. The injury was based on the presence of hemarthrosis, pathologic joint motion, and/or instability of the tibiofemoral joint. From this group, 124 patients were diagnosed with complete ACL tears (112 cases confirmed by arthroscopy, 12 cases diagnosed by the presence of pathologic motion with a KT-1000 arthrometer). Conventional radiographs of the injured knee were obtained in all 150 patients at the time of the acute injury. Five years later, radiographs of both the injured knee and the uninjured contralateral knee were evaluated. The lateral femoral condylopatellar sulcus, or notch, was measured on the acute injury and 5-year follow-up radiographs, and this measurement was compared to that on radiographs of the uninjured contralateral knee. The depth of the lateral sulcus consistently was noted to be similar in both knees in a given patient. Two groups of patients were identified: one group consisted of 124 patients with torn ACLs with a mean notch depth on the injured side of 0.57 mm [range, 0.0–3.3 mm; standard deviation (SD), 0.57 mm] and on the uninjured contralateral side of 0.43 mm (range, 0.0–2.0 mm; SD, 0.42 mm); and a second group consisted of those 26 injured patients with intact ACLs with a mean notch depth on the injured side of 0.31 mm (range, 0.0–1.0 mm; SD, 0.35 mm) and on the uninjured contralateral side of 0.27 mm (range, 0.0–0.8 mm; SD, 0.26 mm). Four of the 124 patients with a proven ACL tear had lateral notch measurements greater than 2.0 mm in depth. No patient with an intact ACL demonstrated a lateral sulcus that exceeded 2.0 mm in depth. A depth greater than 2.0 mm had a specificity of 100%, sensitivity of 3.2%, accuracy of 60%, and a positive predictive value of 100% for complete ACL tear. This work was supported in part by Veterans Affairs Grant SA 206.