Mechanisms of anterior cruciate ligament ruptures in skiing

In the years 1980–1989, 78 patients with an acute anterior cruciate ligament (ACL) rupture sustained during downhill or cross-country skiing were treated at the University Hospital of Tampere, Finland. In every case, the ACL rupture was verified at arthroscopy or open surgery. The injury mechanism could be clarified for 51 patients using a collection of pictures of the most typical injury mechanisms in skiing. Thirty-nine of them (76%) were women and 12 men (24%). In 32 cases (63%) the injury occurred during downhill skiing and in 19 cases (37%) during cross-country skiing. In 24 cases (47%) the injury mechanism was valgus-external rotation, in 21 cases (41%) flexion-internal rotation, in two cases hyperextension-internal rotation, while in four cases the exact mechanism remained unclear. The great majority of the patients with an injury mechanism of flexion-internal rotation were women (90%), and they were significantly older than the patients with an injury mechanism of valgus-external rotation (mean ages 44 and 34 years, respectively:P<0.05). According to the patients' subjective evaluation, the main reasons for the injury were poor ski area conditions (such als slippery slopes and trails) and deficient equipment, especially poorly functioning bindings. Many of them had had little skiing experience before the accident.     

Patellotibial contusions in anterior cruciate ligament tears

Bone contusions are an important ancillary finding of many knee injuries. Not only are they a source of pain, they may suggest a mechanism of injury or a specific derangement of the knee joint. We have encountered a small number of patients being evaluated for anterior cruciate ligament (ACL) tears with unexplained patellar and tibial edema at magnetic resonance (MR) imaging. We present three individuals with contusions of the inferior patella with a corresponding contusion of the anteromedial tibial plateau. Internal derangements in these patients were similar to other individuals with acute ACL tears, however osseous contusions were more widespread. In conclusion, patellotibial contusions are rare and may indicate an injury with forces greater than usually encountered in most ACL tears. A careful search for uncommon associated injuries is prudent in these high-energy knee injuries.     

The course of partial anterior cruciate ligament ruptures

In a prospective study 21 consecutive patients were followed up for an average of 6 years after partial tear of the anterior cruciate ligament (ACL) diagnosed by clinical examination and arthroscopy. The ACL tear was treated conservatively and associated lesions were sutured. At followup a knee function score was recorded. The maximum possible score was 100 points. The mean score at followup was 93 +/- 6 points. All patients were classified as good or excellent. Three knees were unstable at followup, but the score was not impaired. With a partial tear of the ACL the course is benign and the long-term result good, in contrast to total ruptures of ACLs. It is, therefore, important to make an accurate diagnosis in order to choose the proper treatment.     

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.     

Acute anterior cruciate ligament stump entrapment in anterior cruciate ligament tears: MR imaging appearance

PURPOSE: To describe the magnetic resonance (MR) imaging appearance of anterior cruciate ligament (ACL) stump entrapment in patients who presented with decreased knee extension after rupturing the ACL. MATERIALS AND METHODS: MR images in 15 patients who had presented with a block to terminal knee extension after sustaining an ACL tear were retrospectively reviewed. The MR imaging appearances of entrapped ACL stumps were defined and correlated with arthroscopic and histologic findings. RESULTS: The entrapped ACL stumps had two distinct appearances. Type 1 stumps (n = 11) were characterized by a nodular mass located at the anterior aspect of the intercondylar notch, interposed between the lateral femoral condyle and tibia. Type 2 stumps (n = 4) were characterized by a tonguelike free end and angulation of the stump. Histologic evaluation of the resected specimens showed distorted ACL fibers intermixed with variable fibrosis and inflammation. CONCLUSION: Entrapment of an ACL stump can limit knee extension. The two observed appearances of entrapped ACL stumps likely represent two points along a spectrum of appearances, which possibly includes the cyclops lesion.     

前交叉韧带撕裂的MRI诊断

目的:研究膝关节前交叉韧带撕裂的MRI表现。方法:回顾分析30例经关节镜证实的前交叉韧带撕裂MR图像及40例完好的ACL,分析其直接及间接征象的特征。结果:在评价的直接征象中,ACL不连续和ACL走行异常均具有相对高的诊断敏感性、特异性;在评价的间接征象中,后交叉韧带角、Blumensaat角、后交叉韧带指数、半月板后移征、“对吻性”骨挫伤、胫骨前移位等6个征象具有相对高的特异性,后交叉韧带角、Blumensaat角具有较高的敏感性。结论:ACL损伤的直接征象为诊断主要依据,ACL损伤的间接征象具有辅助诊断意义。     

Diagnosis of acute and chronic anterior cruciate ligament tears

The diagnosis of acute and chronic injuries of the ACL has been reviewed. Attention has been given to the history, physical examination, and other diagnostic tools available for evaluation of the ligamentous injury. Clinical correlations have been highlighted. Finally, our recommendations for surgical intervention have been presented.     

Different patterns of meniscal tears in acute anterior cruciate ligament (ACL) ruptures and in chronic ACL-deficient knees

Through the retrospective study of 1103 reconstructions of the anterior cruciate ligament (ACL) performed between 1984 and 1993, we try to outline the natural history of meniscal tears in acute lesions and in chronic insufficiency of the ACL. According to a more accurate evaluation of the clinical evolution, ACL-deficient knees can be classified into four different stages: acute, subacute, subchronic and properly chronic laxities. While acute injuries show a higher rate of lateral meniscus tears, chronic laxities are very frequently associated with severe medial meniscus lesions. Subacute and subchronic stages seem therefore to be the most favourable phases for ACL reconstruction, because of the lower percentage of severe associated meniscus tears and the minor risk of arthrofibrosis.     

Association of peripheral vertical meniscal tears with anterior cruciate ligament tears

OBJECTIVE: The purpose of this article is to describe a type of meniscal tear seen on magnetic resonance (MR) imaging, the peripheral vertical tear, and to determine the prevalence of anterior cruciate ligament (ACL) tears in knees with this type of meniscal tear compared to knees with other types of meniscal tears. MATERIALS AND METHODS: Following Institutional Review Board approval, a retrospective review of 200 knee MR examinations with imaging diagnoses of 'meniscal tear' was performed to assess the location and morphology of the meniscal tear, and to assess the status of the ACL. RESULTS: Nineteen peripheral vertical meniscal tears were identified in 17 patients, 14 of whom had acute ACL tears, prior ACL reconstruction, or chronic ACL deficiency. Three peripheral vertical tears were seen in the setting of a normal ACL. Of the 183 examinations with other types of meniscal tears, there were 17 cases with acute ACL tears, prior ACL reconstruction, or chronic ACL deficiency. The difference in the prevalence of ACL tear, reconstruction, or deficiency in knees with meniscal tears of the peripheral vertical type (82.4%) compared with the prevalence of ACL tear, reconstruction, or deficiency in knees with other types of meniscal tears (9.3%) was statistically significant (P < 0.001). The calculated specificity of the presence of peripheral vertical tear morphology in detecting an ACL injury in patients with meniscal tears was 98.2%. CONCLUSIONS: Peripheral vertical meniscal tears, particularly when involving the posterior horn, are highly associated with ACL tear, deficiency, or reconstruction. The finding of this type of tear on knee MR imaging should prompt close inspection of the ACL for evidence of acute or chronic injury, and its presence may help make the diagnosis of ACL tear in equivocal cases.     

Incidence and long-term follow-up of isolated posterior cruciate ligament tears

Purpose

Isolated posterior cruciate ligament (PCL) tears are an uncommon injury. The goals of this study are to (1) determine the population-based incidence of isolated PCL tears, (2) compare the occurrence of secondary meniscal tears or arthritis in patients with PCL deficiency to patients without PCL tears, and (3) evaluate factors associated with long-term sequelae among patients with PCL deficiency.

Methods

This retrospective study included a population-based incidence cohort of 48 patients with new-onset, isolated PCL tears between 1990 and 2010, as well as an age and sex-matched cohort of individuals without PCL tears. A chart review was performed to collect information related to the initial injury, treatment, and outcomes. Subjects were retrospectively followed to determine the development of subsequent meniscal tears, arthritis, or total knee arthroplasty (TKA).

Results

The age- and sex-adjusted annual incidence of isolated, complete PCL tears was 1.8 (95 % CI 1.3, 2.3) per 100,000. During a mean 12.2-year follow-up, patients with isolated PCL tears had a significantly higher likelihood (HR 6.2, 95 % CI 1.8, 21.2) of symptomatic arthritis compared to individuals without PCL tears. The likelihood of subsequent meniscal tears (HR 2.1, 95 % CI 0.4, 10.7) and TKA (HR 3.2, 95 % CI 0.5, 19.6) was more frequent among patients with PCL tears compared to subjects without PCL tears. Older age at injury was significantly associated with future arthritis (P = 0.003) and TKA (P = 0.02).

Conclusion

Isolated PCL tears remain a rare injury with an estimated annual incidence of 2 per 100,000 persons. Patients with isolated PCL tears have a significantly higher risk of symptomatic arthritis than patients without PCL tears. Older age at injury is associated with a higher risk of arthritis and the need for TKA. The results of this study can be used to educate patients about the natural history of isolated PCL tears and provide a baseline of expectations for the future development of arthritis and subsequent meniscal injury following isolated PCL injury.

Level of evidence

Retrospective comparative study, Level III.

     

Incidence and outcomes of anterior cruciate ligament reconstruction among U.S. Army aviators

BACKGROUND: The incidence, injury history and aeromedical disposition of anterior cruciate ligament (ACL) reconstruction among Army aviators is unknown. METHODS: The U.S. Army Aviation Epidemiology Data Register was queried for the study period of calendar years 1988-95. Factors considered included age, gender, type and mechanism of injury, prior history of ACL reconstruction, and final aeromedical disposition. The population was divided into two groups: Group I aviators had no history of ACL injury before entering aviation service, while Group II aviators had ACL reconstructions prior to entering aviation service. The data set was analyzed to determine the incidence of ACL reconstruction, to characterize the type and mechanism of injury and to determine the risk of aeromedical termination from service. RESULTS: The ACL reconstruction rate (ACL reconstructions/1000 aviators per year) was 0.52 overall, 0.50 for males and 1.39 for females. Sports accounted for 76% of the injuries requiring ACL reconstruction. The ACL reconstruction rate in Group I was 0.050%, while that of Group II was 63.3%. Among Group I aviators requiring ACL reconstruction, 94.3% returned to aviation service, 2.3% were aeromedically terminated and 3.4% were lost to follow-up. Among Group II aviators requiring revision ACL reconstruction, 60% returned to aviation service and 40% were aeromedically terminated. CONCLUSION: Female aviators and Group II aviators had the greatest risk of requiring ACL surgery. Group II aviators had a greater likelihood of undergoing a revision ACL reconstruction and subsequent aeromedical termination compared with an initial ACL reconstruction for Group I aviators.     

Accuracy of MRI patterns in evaluating anterior cruciate ligament tears

 The purpose of this study was to determine the different patterns of anterior cruciate ligament (ACL) tears on MRI and the prevalence and accuracy of these patterns. Images were obtained on high-tesla and low-tesla units and the results compared to determine whether field strength affects the interpretation using the grading system. In 172 patients who underwent knee MRI (109 knees with high-tesla units and 63 knees with low-tesla units) and arthroscopy, there was a total of 91 arthroscopically proven ACL tears. Five patterns of ACL tears were observed and designated as type 1 (diffuse increase in signal on T2-weighted images and enlargement of the ligament, 48%); type 2 (horizontally oriented ACL, 21%); type 3 (nonvisualization of the ACL, 18%); type 4 (discontinuity of the ACL, 11%); and type 5 (vertically oriented ACL, 2%). The positive predictive value (PPV) for type 2, 4, and 5 patterns was 100% for both field strengths; for type 3 PPV was just above 80% for both field strengths. The PPV value for type 1 was 90% for the high-tesla unit and 79% for the low-tesla, unit, which was not statistically significant. Combining the results of both field strengths, the overall sensitivity and specificity were 93% and 89%, respectively. Arthroscopic results were also used to determine the association between meniscal and ACL tears. Only 13% of ACL tears were isolated, the rest being associated with meniscal tears. Forty-five percent of medial meniscal and 50% of lateral meniscal tears were associated with an ACL tear, and 94% of ACLs were torn when both menisci were torn.     

关节镜下4股半腱肌腱单束重建前交叉韧带部分损伤

目的 介绍关节镜下单束蕈建增强治疗前交叉韧带(anterior cruciate ligament,ACL)后外侧束部分损伤方法 ,探讨其临床效果. 方法 对26例单纯ACL后外侧柬部分损伤患者,在关节镜下采用自体半腱肌腱进行单束解剖重建.按照国际膝关节评分委员会(internationalknee documentation committee,IKDC)和Lysholm膝关节功能评分表对患膝功能进行评估,通过KT-1000检查比较膝关节的前向松弛度. 结果 术后无活动受限,屈膝活动度130°～150°,平均142°.术后随访12～18个月,最后随访时IKDC评分为A级25例(96%),B级1例(4%);IKDC评分从术前的(71.4±3.7)分提高到随访结束时的(95.8±3.4)分(t=9.836,P<0.01).屈膝25°位KT-1000检查,双侧膝关节胫骨结节前移差异从术前的(5.1±1.2)mm减少到终末随访的(2.1±1.3)mm(t=10.48,P<0.01).患者术前Lysholm膝关节功能评分为(76.7±3.2)分,终末随访时为(95.7±2.4)分(t=7.356,P<0.01). 结论 在关节镜下采用自体半腱肌腱单束解剖重建增强治疗ACL后外侧束部分损伤,能取得良好效果.     

Management of anterior cruciate ligament tears in skeletally immature athletes

The prevalence of anterior cruciate ligament (ACL) injuries in skeletally immature athletes has increased dramatically over the past decade. Many attribute this to increased training, single-sport specialization and year-round competitive play. ACL injuries most commonly occur in athletic activities that involve cutting, pivoting, jumping and landing. Non-operative treatment consisting of activity modification, physical therapy and specialized bracing may have a role; however, recent data suggest that this may not be optimal in young, active patients. Surgical treatment has become more favorable, specifically for athletes with aspirations of higher-level sports participation. To minimize growth plate disturbances and potential for limb malalignment, the patient’s skeletal age, pubertal status and remaining growth potential must be taken into consideration. We provide a review on how to evaluate, manage and treat the skeletally immature athlete with an ACL injury.     

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.     

Surgical management of partial tears of the anterior cruciate ligament

Purpose

Partial anterior cruciate ligament (ACL) tears involving the posterolateral (PL) bundle can lead to rotatory laxity of the knee, while tears involving the anteromedial (AM) bundle result in abnormal anteroposterior laxity of the knee. In this systematic review, we examine the best evidence on the management of partial tears of the ACL.

Methods

A comprehensive search of several databases was performed from the inception of the database to December 2011, using various combinations of keywords focusing on clinical outcomes of human patients who had partial tears of ACL and who had undergone ACL augmentation. We evaluated the methodological quality of each article using the Coleman Methodology Score.

Results

Ten articles published in peer-reviewed journals were identified (392 males and 242 females), with a mean modified Coleman methodology of 66.1 ± 10.2. Only two studies compared standard ACL reconstruction and augmentation techniques. No study has a sample large enough to allow establishing guidelines. Validated and standardized proprioception assessment methods should be used to report outcomes. Imaging outcomes should be compared to functional outcomes, and a control group consisting of traditional complete ACL reconstruction should be present.

Conclusion

There is a need to perform appropriately powered randomized controlled trials presenting clinical outcome with homogeneous score systems to allow accurate statistical analysis. ACL augmentation technique, preserving the intact AM or PL bundle of the ACL, is encouraging but currently available evidences are too weak to support his routine use in clinical practice.

Level of evidence

Systematic review, Level IV.     

Magnetic resonance diagnosis of meniscal tears in patients with acute anterior cruciate ligament tears

OBJECTIVE: To evaluate the accuracy of magnetic resonance imaging in the diagnosis of meniscal tear in patients with acute anterior cruciate ligament tears. METHODS: Magnetic resonance images obtained from 41 patients imaged within 6 weeks of injury who had acute anterior cruciate ligament tears identified at arthroscopy were retrospectively reviewed for meniscal tear. RESULTS: With MR imaging the sensitivity, specificity and accuracy for diagnosing meniscal tears in the presence of acute anterior cruciate ligament tears were 71%, 93%, and 88%; for the lateral meniscal tears were 57%, 100% and 85%; and for the medial meniscal tears were 100%, 88%, 90%. All false negative cases (n = 6) involved the posterior horn of the lateral meniscus. CONCLUSION: In the presence of acute anterior cruciate ligament tears, MRI imaging has relatively low sensitivity for detecting meniscal tears due to missed tears in the lateral meniscus.