Meniscal extrusion in young athletes: associated knee joint abnormalities

OBJECTIVE: The objective of our study was to assess the rate of meniscal extrusion and its connection with common meniscal and joint abnormalities. MATERIALS AND METHODS: MR signs of meniscal extrusion were evaluated retrospectively in 24 rugby and soccer players (40 knees) who are currently free of pain in the knee, impaired mobility, and joint swelling. The control group consisted of 23 consecutive active individuals (36 knees) with no history of knee problems. The criterion for extrusion of the meniscus was defined as a distance of 3 mm or more between the peripheral border of the meniscus and the edge of the tibial plateau measured on coronal images. RESULTS: Forty-eight percent of the athletes' knees and 30% of the control subjects' knees showed evidence of meniscal extrusion. Among the athletes, a significant association between meniscal extrusion and joint effusion (11 cases), meniscal tears (seven cases), and anterior cruciate ligament (ACL) tear (four cases) was found (p < or = 0.004). In the control group, no significant association was found between meniscal extrusion and joint effusion (three cases), meniscal tears (four cases), and ACL tears (two cases) (p = 1.00). A significant association was not found between degenerative change and meniscal extrusion in either the athletes (p = 0.23) or the control subjects (p = 1.00). The most commonly associated knee abnormality was joint effusion in 73% of knees with meniscal extrusion in athletes. CONCLUSION: Meniscal extrusion is a common finding on MRI of athletes' knees. Meniscal extrusion in association with meniscal tear and joint effusion is postulated as a significant injury in athletes and its recognition as such in this group is important because it may prompt orthopedic intervention.     

Prospective evaluation of 1485 meniscal tear patterns in patients with stable knees

BACKGROUND: Despite emphasis on classifying meniscal tears based on healing potential of the tear, research has concentrated on unstable knees, and few reports have provided information regarding associated clinical variables in stable knees. PURPOSE: To report on a large series of meniscal tears in stable knees that have been carefully mapped by tear shape and tear zones to allow comparison with meniscal tears in unstable knees. STUDY DESIGN: Prospective case series, reviewed retrospectively. METHODS: A total of 1485 meniscal tears in stable knees were evaluated. Preoperatively, each patient underwent a standardized assessment. Each tear was carefully mapped at arthroscopy. Statistical analysis was performed to determine factors that may be associated with peripheral meniscal tears. RESULTS: The distribution and shape of tears varied significantly within the radial and circumferential zones in this stable knee population. Five prospective variables were associated with peripheral tears: gender, presence of an effusion, positive McMurray test, varus alignment, or a loss of extension more than 5 degrees. CONCLUSIONS: Patient demographic information and physical examination can be useful in identifying patients who may have a peripheral meniscus tear.     

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.     

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.     

Medial meniscus extrusion on knee MRI: is extent associated with severity of degeneration or type of tear?

OBJECTIVE: The meniscus is considered "extruded" when it extends beyond the tibial margin. We hypothesize that severe degeneration, large radial tears, complex tears, and tears involving the meniscal root would alter meniscal stability and cause more substantial extrusion. MATERIALS AND METHODS: The knee MRI database at Thomas Jefferson University Hospital was searched for reports describing meniscal extrusion; MR images were reviewed retrospectively. On mid coronal images, extrusion of the medial meniscus was quantified in millimeters. A separate, independent review of the meniscus evaluated degeneration severity and tear (type and extent). Radial tears were divided into those involving more (large) or less (small) than 50% of the meniscal width. Tears that involved the "root" at the tibial spine were recorded. Chi-square analysis compared these findings with extrusion extent, divided into minor ( 3 mm) extrusion. RESULTS: One hundred five knees were reviewed (12 men and 93 women; age range, 34-83 years; mean age, 56 years). Distribution of medial meniscus extrusion was 2 mm (n = 17), 3 mm (n = 17), 4 mm (n = 27), 5 mm (n = 14), 6 mm (n = 16), and 7-10 mm (n = 14). Mild, moderate, or marked degeneration was seen in 47%, 26%, and 27% with minor extrusion, respectively, and in 17%, 41%, and 42% with major extrusion, respectively (p = 0.003). Tears were seen in 59% (20/34) with minor extrusion versus 89% (63/71) with major extrusion (p = 0.001). Tears involved one third, two thirds, or all of the meniscus in 75%, 25%, or 0%, respectively, with minor extrusion and 46%, 40%, or 14% with major extrusion, respectively (p = 0.014). Longitudinal (nonradial) and horizontal tears were not associated with extent of extrusion (p = 1.0). Oblique tears were significantly associated with minor extrusion (minor, 26% [9/34]; major, 4% [3/71]; p = 0.003). Radial tears were seen in 9% (3/34) with minor extrusion versus 21% (15/71) with major extrusion (p = 0.20). All three radial tears with minor extrusion were small; conversely, 87% (13/15) of radial tears with major extrusion were large (p = 0.019). Complex tears were seen in 18% (6/34) with minor extrusion versus 59% (42/71) with major extrusion (p < 0.001). Tears involving the meniscal root were seen in 3% (1/34) with minor extrusion and 42% (30/71) with major extrusion (p < 0.001). CONCLUSION: Substantial medial meniscus extrusion (> 3 mm) is associated with severe meniscal degeneration, extensive tear, complex tear, large radial tear, and tear involving the meniscal root.     

Three-dimensional axial volume acquisition on meniscal lesions of the knee]

Axial three-dimensional volume scans obtained by magnetic resonance (MR) imaging were used to evaluate meniscal lesions of the knee in 28 knees of 26 cases. Axial 0.7 mm thin-sliced images with volume scan outlined the overall meniscal appearance for the first time. Axial volume scan was essential to the diagnosis of discoid lateral meniscus because only it could depict the characteristic elongated appearance of discoid lateral meniscus. Radial meniscal tears were depicted only by this technique: conventional sagittal and coronal views could not detect this type of meniscal tear. Volume scan could detect the precise extent of lesions with horizontal meniscal tears and meniscal degeneration. These MR findings obtained by axial volume scans were confirmed by arthroscopy in all cases. We concluded that volume scans were extremely useful in the evaluation of meniscal lesions because they offered axial views that provided much information on menisci located horizontally in the knee.     

MR imaging of meniscal cysts: incidence, location, and clinical significance.

OBJECTIVE: The purpose of this study was to determine the incidence of medial versus lateral meniscal cysts as seen on MR imaging. MATERIALS AND METHODS: A total of 2572 knee MR imaging reports were retrospectively reviewed for the presence of meniscal tears and cysts. Two musculoskeletal radiologists reviewed all images with reported cysts. The type and location of meniscal tear and the presence and location of meniscal cysts were recorded. RESULTS: A total of 1402 meniscal tears were reported in 2572 MR examinations (922 [66%] of 1402 in the medial compartment; 480 [34%] of 1402 in the lateral compartment). Meniscal cysts were present in 109 (4%) of 2572 knees. Of the 109 cysts, 72 (66%) were in the medial compartment, and 37 (34%) were in the lateral compartment. Meniscal cysts were found in association with 72 (7.8%) of the 922 medial meniscal tears and 37 (7.7%) of the 480 lateral meniscal tears. Meniscal cysts showed direct contact with an adjacent meniscal tear in 107 (98%) of 109 cases, with the tear showing a horizontal component in 96 (90%) of 107 cases. CONCLUSION: Meniscal cysts occur almost twice as often in the medial compartment as in the lateral compartment. Medial and lateral tears occur with the same frequency. These findings, when viewed in the context of the historical literature on meniscal cysts, suggest that MR imaging detects a greater number of medial meniscal cysts than physical examination or arthroscopy, and that MR imaging can have an important impact on surgical treatment of patients.     

外伤性膝关节前外侧韧带损伤的MR影像特征及相关性分析

目的探讨外伤所致膝关节前外侧韧带损伤病人的MR影像特征,并分析其与前交叉韧带撕裂、外侧半月板撕裂及骨挫伤的相关性,为深入研究前外侧韧带对膝关节稳定性的作用提供可靠依据。方法回顾性分析2016年1月—2017年2月间因外伤进行膝关节MRI检查的320例病人(共321膝)的影像资料。采用美国GE公司生产的Signa HDe 1.5 T MR扫描设备,分别行膝关节斜矢状面T1WI、质子密度加权成像(PDWI)和冠状面、横断面PDWI扫描。根据前外侧韧带的完整性和损伤部位对所有病人进行分类统计。采用独立性卡方检验对前外侧韧带撕裂与前交叉韧带撕裂、外侧半月板撕裂及骨挫伤的相关性进行分析。结果全部病人膝关节MR影像均可显示前外侧韧带,显示率为100%。151/321膝(47.0%;95%CI为41.6%~52.5%)存在前外侧韧带损伤,其中累及胫骨部、股骨部及半月板部的分别为97膝、96膝及65膝。前交叉韧带撕裂158膝,外侧半月板撕裂98膝,股骨外侧髁挫伤58膝,外侧胫骨平台挫伤71膝,分别与前外侧韧带撕裂具有相关性(均P0.001)。结论 MRI检查可以很好地显示前外侧韧带解剖及其损伤情况。膝关节前外侧韧带损伤与前交叉韧带撕裂、外侧半月板撕裂及膝外侧骨挫伤具有相关性。     

Hemi-bucket-handle tears of the meniscus: appearance on MRI and potential surgical implications

Objectives

To describe a type of meniscus flap tear resembling a bucket-handle tear, named a “hemi-bucket-handle” tear; to compare its imaging features with those of a typical bucket-handle tear; and to discuss the potential therapeutic implications of distinguishing these two types of tears.

Materials and methods

Five knee MR examinations were encountered with a type of meniscus tear consisting of a flap of tissue from the undersurface of the meniscus displaced toward the intercondylar notch. A retrospective analysis of 100 MR examinations prospectively interpreted as having bucket-handle type tears yielded 10 additional cases with this type of tear. Cases of hemi-bucket-handle tears were reviewed for tear location and orientation, appearance of the superior articular surface of the meniscus, presence and location of displaced meniscal tissue, and presence of several classic signs of bucket-handle tears.

Results

A total of 15/15 tears involved the medial meniscus, had tissue displaced toward the notch, and were mainly horizontal in orientation. The superior surface was intact in 11/15 (73.3%). In 1/15 (6.7%) there was an absent-bow-tie sign; 6/15 (40%) had a double-PCL sign; 14/15 (93.3%) had a double-anterior horn sign.

Conclusion

We describe a type of undersurface flap tear, named a hemi-bucket-handle tear, which resembles a bucket-handle tear. Surgeons at our institution feel this tear would likely not heal if repaired given its predominantly horizontal orientation, and additionally speculate the tear could be overlooked at arthroscopy. Thus, we feel it is important to distinguish this type of tear from the typical bucket-handle tear.     

An arthroscopic analysis of lateral meniscal variants and a comparison with MRI findings

We reviewed 164 consecutive cases (158 patients) of arthroscopic examinations for lateral meniscal variants during the last 10 years. We classified lateral meniscal variants into four types by arthroscopic appearance, into six tear patterns by modifying OConnors classification, and compared magnetic resonance images (MRI) with arthroscopic findings. Regarding the four types, 131 cases were complete, 25 cases were incomplete, 4 cases were Wrisberg, and 4 cases were ring-shaped meniscus. The six tear patterns were as follows: 33 simple horizontal, 21 combined horizontal, 37 longitudinal, 27 central, 14 complex, and 12 radial tear. Among the 31 knees with a central tear or ring-shaped meniscus, we reviewed 25 MR images. Fifteen (60%) MRI findings were interpreted to represent a bucket-handle (displaced) tear of the normal C-shaped meniscus; 7(28%) MRI findings, a discoid meniscal tear; and the remaining 3(12%) MRI findings, a simple meniscal tear. Moreover, all ring-shaped menisci were interpreted as a displaced lateral meniscal tear on the MRI findings. Twelve patients (13 knees, 7.9%) had osteochondritis dissecans: Nine patients (10 knees) of them had a central tear, two patients (2 knees) of them had a simple horizontal tear of the discoid meniscus, and one patient (1 knee) had a ring-shaped meniscus. Twenty three patients (92.6%) with a central tear of the discoid meniscus did not have any traumatic events. For the differential diagnosis of a central tear or a ring-shaped meniscus from a bucket-handle tear of the normal C-shaped meniscus, we should take a careful history, in particular any traumatic events, we should also consider the possibility of misinterpreting the MR images though these images can provide additional information about associated abnormalities and probe carefully in the arthroscopic operations.     

膝关节半月板撕裂磁共振成像与关节镜对照研究

目的分析磁共振成像（MRI）在膝关节半月板撕裂诊断中的价值。方法分析168例（共计336个半月板）临床疑诊半月板损伤患者,依次在1周内行磁共振（MR）和关节镜检查,对比MR和关节镜检查结果,探讨MRI对膝关节半月板撕裂诊断符合率。结果以关节镜为参考标准,168例（共计336个半月板）中MRI诊断半月板撕裂敏感性96．9％,特异性为87．5％,准确性为92．5％,假阳性率为12．5％,假阴性率3．1％,MRI具有术前诊断价值。结论MRI诊断半月板撕裂具有很高准确性,但仍有一定的假阳性与假阴性。     

Analysis of meniscal and chondral lesions accompanying anterior cruciate ligament tears: relationship with age,time from injury,and level of sport

The purposes of this multi-center study were: (a) to document the location and type of meniscal and chondral lesions that accompany anterior cruciate ligament (ACL) tears, and (b) to test for possible relationships between these lesions and patient age, time from initial injury (TFI), and sports level (i.e., recreation, amateur, professional, and national). The cases of 764 patients with ACL tears who underwent arthroscopy for the first time were retrospectively analyzed. The group included 684 males and 80 females of mean age 27 years (range 14–59 years). The mean TFI was 19.8 months (range 0.2–360 months). Eighty-seven percent of the group engaged in regular sporting activity. Thirty-seven percent had medial meniscal tears, 16% had lateral meniscal tears, and 20% had tears of both menisci. The most common tear types were longitudinal tears in the posterior and middle horns of both menisci. Tears of the lateral meniscus were more centrally located than those of the medial meniscus. Incomplete tears and radial tears were significantly more common in the lateral meniscus. Nineteen percent of the knees had one or more chondral lesions. Sixty percent of the chondral lesions were located in the medial tibio-femoral compartment. Patient age was statistically associated with presence of a medial meniscal tear, presence of a grade 3 or 4 chondral lesion, and presence of a complex tear of the medial meniscus. Sports level was not statistically related to any of the parameters studied. The odds of having a medial meniscal tear at 2 to 5 years TFI were 2.2 times higher than the odds in the first year post-injury, and the odds at >5 years were 5.9 times higher than at 0 to 12 months TFI. The frequency of lateral meniscal tear remained fairly constant at 2 years TFI. The odds of having a grade 3 or 4 chondral lesion were 2.7 times greater at 2 to 5 years TFI than they were at 1 year post-injury, and these odds increased to 4.7 when patients at >5 years TFI were compared to those in the 2 to 5 years category. Multivariate analysis demonstrated that TFI and age were equally important predictors of lateral meniscal tears and of grade 3 or 4 chondral lesions; however, TFI was the better predictor of medial meniscal tear.This multi-center study was performed by the Turkish Society of Sports Traumatology, Arthroscopy and Knee Surgery. It was presented as a poster at the ESSKA 2000 Congress in London, UK     

Correlation between type of discoid lateral menisci and tear pattern

This study analyzed the relationship between type of discoid lateral menisci and tear pattern. There were 108 consecutive cases (103 patients) with discoid lateral meniscus tear treated by arthroscopy. Regarding type of discoid meniscus (Watanabe's classification), 38 cases were "complete" and 70 cases "incomplete." There was no Wrisberg type. Tear patterns were classified into simple horizontal, complicated horizontal, longitudinal, radial, degenerative, and complex tear. The relationship between tear pattern and type of discoid menisci was statistically highly significant. Simple horizontal tear was found only in the complete type of case, and radial, degenerative, and complex tears were found only in the incomplete type of case. In the longitudinal tear, however, we found no correlation between tear pattern and type of discoid meniscus. In addition, the extent of meniscal resection was dependent on the tear pattern. Subtotal or total meniscectomy was performed significantly more frequently in longitudinal and complex tears. In radial and degenerative tears only partial meniscectomy was carried out. Complicated horizontal tears showed no difference in extent of resection. Among the 13 cases of simple horizontal tears partial meniscectomy was performed in 12 cases. These findings about relationship between the type of discoid menisci and tear pattern could be useful in planning operation and deciding extent of resection.     

Relationship between bone bruise volume and the presence of meniscal tears in acute anterior cruciate ligament rupture

Purpose

To determine whether there is a relationship between the size of the bone bruise volume after an acute anterior cruciate ligament (ACL) rupture and the presence of meniscal tears in the medial and lateral compartment.

Methods

Following Institutional Review Board approval, 50 patients with an acute ACL rupture and MRI imaging within 30 days of injury were identified. Two musculoskeletal radiologists evaluated the lateral and medial menisci and graded them as one of the following: no meniscal tear, tear of one meniscus (medial or lateral) or tear of both menisci (medial and lateral). Sagittal T2 fat-suppressed images were used to calculate bone bruise volume. The relationship between bone bruise volume and the presence of a meniscus tear was calculated.

Results

Forty-three (86 %) patients had a bone bruise, 16 (32 %) patients had no tear, 7 (14 %) patients had lateral meniscus tear, 13 (26 %) patients had medial tear and 14 (28 %) patients had medial and lateral tears. There was a statistically significant difference in femoral bone bruise volume when comparing no meniscal tear to medial and lateral tears as well as when comparing medial or lateral tears to medial and lateral tears.

Conclusion

There is a statistically significant relationship between femoral bone bruise volume and the presence of meniscal tears in ACL injury, especially in the setting of medial and lateral pathology.

Level of evidence

Retrospective cohort study, Level III.     

膝关节半月板囊肿22例MRI分析

目的：分析膝关节半月板囊肿的MRI特点，提高对该病的认识。方法：回顾性分析22例膝关节半月板囊肿的MRI表现并与关节镜或手术结果对照。探讨半月板囊肿发生的部位、形态、信号特征及与半月板的毗邻关系。结果：22例半月板囊肿中，内侧半月板囊肿4例(18．1％)，外侧半月板囊肿18例(81．8％)。22例半月板囊肿中显示半月板水平撕裂15例(68．2％)，纵行撕裂3例(18．1％)。结论：半月板囊肿好发于外侧半月板，并与半月板的撕裂相关，表明MRI对诊断半月板囊肿有较高的临床价值。     

膝关节内侧盘状软骨损伤13例病历分析

目的:回顾性研究13例膝关节内侧盘状软骨损伤患者(随访11例)的临床表现和手术治疗效果。方法:对我所收治的13例内侧盘状软骨损伤患者的临床特征、手术方式、治疗效果和影像学改变等进行评估,并结合文献进行分析。结果:内侧盘状软骨损伤占全部半月板损伤的1.35‰,男性多见。内侧盘状软骨分为完全型和不完全型两种类型。损伤发生年龄平均为(28.8±14.0)岁,损伤机制多为屈膝内旋损伤,损伤类型以纵裂和层裂多见。临床症状以疼痛、肿胀、弹响和打软为主,体征以内侧关节间隙压痛最为典型。手术以盘状软骨切除为主,近期效果良好:术后2年的Tegner评分为7(4~9)分,Lysholm评分为94.8±2.4。远期效果由于内侧关节间室退变而变差。结论:内侧盘状软骨损伤少见,临床特征同一般半月板损伤,无特异性表现。盘状软骨切除近期效果良好,远期效果由于内侧关节间室的退变而逐渐变差。     

半月板下表面撕裂的MRI影像学表现

目的 探讨半月板下表面撕裂(meniscus lower surtace tear,MLST)的MRI影像学表现及与半月板撕裂传统分型的差异.方法 以"桶柄状撕裂""水平撕裂""复杂撕裂"为关键词,检索2018-06至2021-06在医院影像归档系统(picture archiving and communicatio...     

The O'Donoghue triad revisited. Combined knee injuries involving anterior cruciate and medial collateral ligament tears

We identified 60 consecutive patients with combined anterior cruciate and medial collateral ligament (ACL-MCL) disruptions that were incurred during athletic endeavors. Each underwent acute reconstruction of the ACL. The arthroscopic data obtained at the time of reconstructive surgery was reviewed in order to determine the incidence of O'Donoghue's triad (the "unhappy triad"), consisting of ACL, MCL, and medial meniscus tears. Patients were subdivided into two groups for analysis based upon the degree of MCL injury at time of presentation (Group I, 35 patients with a second-degree sprain; Group II, 25 patients with a complete, or third-degree injury). Medial meniscus tears were an uncommon finding. Lateral meniscus tears significantly out-numbered medial meniscus tears in both groups, occurring in 25 (71%) of Group I patients and 8 (32%) of those in Group II. Even chondral fractures of the lateral femoral condyle outnumbered medial meniscus tears [6 (17%) versus 4 (11%)] in patients with a second-degree MCL sprain. Furthermore, when present in Group I patients, tears of the medial meniscus were associated with a concomitant lateral meniscus injury. Group II patients were more likely (60%) than Group I not to have any meniscal abnormality at all. We conclude that the classic O'Donoghue triad is, in fact, an unusual clinical entity among athletes with knee injuries; it might be more accurately described as a triad consisting of ACL, MCL, and lateral meniscus tears. This injury combination appears to be more common when an incomplete, or second-degree, tear of the medial collateral has occurred.(ABSTRACT TRUNCATED AT 250 WORDS)     

半月板损伤部位与临床查体阳性体征的相关性研究

目的:分析半月板损伤部位与半月板损伤查体之间的对应关系,评价各种临床查体方法对半月板损伤诊断的临床价值。方法:对2009年3月~2011年3月通过临床查体及MRI诊断以及关节镜检确诊半月板损伤的114例(123膝)患者进行回顾性分析,研究半月板损伤各种查体方法对于诊断不同部位半月板损伤的敏感度和特异性。结果:各种半月板损伤的查体方法对诊断半月板损伤有着重要的提示作用,并与半月板损伤部位存在明显的相关性。结论:多个相关临床查体相结合可提高半月板损伤诊断的准确率。     

A comparison of acute anterior cruciate ligament examinations. Initial versus examination under anesthesia

The preoperative examination, the examination under anesthesia, and the findings at surgery were compared for acutely injured knees that were found at surgery to have anterior cruciate ligament (ACL) tears. The pivot shift was initially positive in only 35% of the knees; however, under anesthesia 98% were positive. The Lachman test was initially positive in 99% of the knees, and under anesthesia, 100%. The anterior drawer sign was present initially in 70% of the knees, and under anesthesia this increased to 91%. Of the 37 patients with isolated ACL tears, only 20 (54%) had initially positive anterior drawer signs. In the knees in which secondary restraints to anterior-posterior motion were injured, this percentage increased to 69% in medial meniscus injury, 82% in lateral meniscus injury and 89.5% in rupture of the medial collateral ligament (MCL). The Lachman test seems relatively unaffected by associated ligamentous or meniscal injuries, but the end point in the Lachman test is absent in all complete ACL tears. The pivot shift phenomenon, which was demonstrable in 98% of patients when tested under anesthesia, may be diminished when there is a MCL injury or absent in partial ACL tears. Experience in performing the Lachman test and in appreciating the quality of the end point will give the examiner a high degree of accuracy in making the diagnosis of an ACL tear without resorting to anesthesia, arthroscopy, or arthrography in most patients.