Healing results of meniscal tears left in situ during anterior cruciate ligament reconstruction: a review of clinical studies

The presence of peripheral meniscal tears is common at the time of anterior cruciate ligament (ACL) reconstruction. Techniques to preserve the maximum amount of meniscal tissue include “non operative” management (tear left alone, without repair or removal), meniscus repair, partial meniscectomy. There is a lack of consensus guidelines about the management of peripheral stable meniscal tears. When to remove, let alone or repair? We performed an evidence-based review of the outcomes of stable meniscal tears left in situ during ACL surgery, in order to assess the effectiveness of this popular procedure. Clinical and anatomical results (arthrography or second look arthroscopy) were analyzed. Our literature search yielded ten relevant studies (9 level IV, 1 level III). The mean time of follow-up was 16 months. Pain or mechanical symptoms related to the medial tibiofemoral joint were reported in 0–66% of cases. Subsequent medial meniscectomy or repair were performed in 0–33% of cases. Pain or mechanical symptoms related to the lateral tibiofemoral joint were reported in 0–18% cases. Subsequent lateral meniscectomy or repair were performed in 0–22% cases. A complete healing occurred in 50–61% cases for the medial meniscus and in 55–74% cases for the lateral meniscus. No definite conclusion can be made with regard to these results. The conservative approach is more effective for lateral menisci. The rate of bad results for the medial meniscus remains high when a conservative treatment is used. For the medial meniscus, repair of stable peripheral tears may be always indicated to decrease the risk of postoperative pain or subsequent meniscectomy.     

Bucket handle tears of the medial meniscus: meniscal intrusion rather than meniscal extrusion

Objective To determine the frequency of medial meniscal extrusion (MME) versus “medial meniscal intrusion” in the setting of bucket handle tears. Images were evaluated for previously reported risk factors for MME, including: medial meniscal root tear, radial tear, degenerative joint disease and joint effusion. Methods Forty-one consecutive cases of bucket handle tear of the medial meniscus were reviewed by consensus by two musculoskeletal radiologists. Imaging was performed using a 1.5 GE Signa MR unit. Patient age, gender, medial meniscal root integrity, MME, medial meniscal intrusion, degenerative joint disease, effusion and anterior cruciate ligament (ACL) tear were recorded. Results Thirteen females and 27 males (age 12–62 years, median=30 years) were affected; one had bucket handle tear of each knee. Effusion was small in 13, moderate in 9 and large in 18. Degenerative joint disease was mild in three, moderate in two and severe in one. 26 ACL tears included three partial and three chronic. Medial meniscal root tear was complete in one case and partial thickness in two. None of the 40 cases with an intact or partially torn medial meniscal root demonstrated MME. MME of 3.1 mm was seen in the only full-thickness medial meniscal root tear, along with chronic ACL tear, moderate degenerative joint disease and large effusion. Medial meniscal intrusion of the central bucket handle fragment into the intercondylar notch was present in all 41 cases. Conclusion Given an intact medial meniscal root in the setting of a “pure” bucket handle tear, there is no MME.     

Medial and lateral meniscal tear patterns in anterior cruciate ligament-deficient knees. A prospective analysis of 575 tears

We used our database to evaluate the locations of meniscal tears associated with anterior cruciate ligament injuries. Five hundred seventy-five meniscal tears were seen in 476 patients. Each tear was categorized prospectively according to the side (medial/lateral), the radial zone of the tear, and the circumferential zone of the tear. The different tear locations were then compared for the medial and lateral menisci and evaluated for statistical significance. We found a nearly equal number of tears on the medial (305) and lateral (270) sides. A significantly greater number of tears on the medial side as compared with the lateral side were posterior (99.4% versus 87.8%) and peripheral (75.4% versus 44.1%). Peripheral posterior horn tears of the medial meniscus were the most common type of tear (230 of 575, 40%) by a statistically significant amount.     

Magnetic resonance imaging findings of surgically proven medial meniscus root tear: tear configuration and associated knee abnormalities

OBJECTIVE: To evaluate magnetic resonance imaging (MRI) findings of medial meniscal root tear and the correlation of medial meniscal root tear with other associated knee abnormalities. METHODS: We retrospectively assessed preoperative magnetic resonance images of 39 patients with arthroscopically confirmed medial meniscal root tear. Magnetic resonance imaging findings were retrospectively reviewed by 2 experienced musculoskeletal radiologists for consensus. We evaluated the configuration of meniscal root tear and the other associated knee abnormalities on MRI for direct correlation with arthroscopic findings. RESULTS: At arthroscopy, there were 36 radial tears and 3 complex tears involving the medial meniscal posterior horn roots. All 36 radial tears could be correctly diagnosed by MRI, with findings showing ghost sign on sagittal images in 100% (36/36), vertical linear defect on coronal images in 100% (36/36), and radial linear defect on axial image in 94% (34/36). However, all 3 complex tears were misdiagnosed as radial tears on MRI. Medial meniscal root tears displayed a strong association with degenerative joint disease in 97% (38/39). Medial meniscal root tears were also found in association with cartilage defects of the medial femoral condyle and medial meniscal extrusions (> or =3 mm) in 89% (34/38) and 67% (26/39), respectively. CONCLUSIONS: Medial meniscal root tears were usually posterior horn root radial tear. A high association with degenerative joint disease, cartilage defects of the medial femoral condyle, and medial meniscal extrusions (>/=3 mm) were also noted.     

Meniscal tears on knee arthrography: Patterns of arthrographic abnormalities

The presence or absence of a meniscal tear was established in 340 out of 475 consecutive patients who had double contrast knee arthrograms. The accuracy in these 340 cases was 95% for both the medial and lateral menisci although the specificity for lateral tears was only 0.64. Analysis of the pattern of arthrographic abnormalities revealed that both medial and lateral tears usually involved the posterior horn of the meniscus. Posterior horn abnormalities rarely caused a false positive diagnosis of a meniscal tear. In contrast, isolated blunting of the anterior horn of either the lateral or medial meniscus was an unreliable sign of a tear and accounted for many of the false positive diagnoses. It is concluded that careful attention to the posterior horn of each meniscus is essential for accurate arthrographic diagnosis of a meniscal tear.     

Patterns of meniscal injury associated with acute anterior cruciate ligament injury in skiers.

To determine if the incidence and patterns of meniscal injury associated with acute anterior cruciate ligament injury in skiers are different from those seen in individuals injured in nonskiing athletic activities, we reviewed the records of 150 patients with acute anterior cruciate ligament injuries. All patients had undergone arthroscopic evaluation within 21 days from the time of injury. There were 75 individuals who were injured while skiing and 75 individuals who sustained an injury in some other high-load athletic activity. Associated meniscal injury was documented at the time of arthroscopy and characterized by location, region, zone, depth, shape, size, and stability. Thirty-one of 75 skiers had an associated meniscal injury as compared to 47 of 75 of the nonskiers. This suggested a strong trend of decreased incidence of meniscal injury in the skier group, but the nonskiers had a higher incidence of major meniscal tears that required repair or partial meniscectomy. The location of the meniscal tear was also significantly different. The incidence of isolated lateral meniscal injury in skiers was higher than in nonskiers. There was a strong trend of increased incidence of medial meniscal involvement in the nonskiers than in the skiers. While there was no difference in the zone or region of tear between the two groups, the skier group was more likely to have a longitudinal tear of the posterior horn of the lateral meniscus. In both groups, lateral meniscal tears were more likely to require conservative treatment or partial meniscectomy while medial meniscal tears were more likely to be repaired than excised.     

A new surgical technique for arthroscopic repair of the meniscus root tear

Injury of the meniscal root can lead to meniscal extrusion and loss of normal hoop stress distribution by the meniscus. This has been shown to result in an excessive tibiofemoral contact pressures and has been associated with development of arthritis in the affected compartment of the knee. Repair of meniscal root avulsion has been shown to restore the normal contact stresses, and several techniques for such repair have been described. We report an all-arthroscopic technique that allows anatomic reattachment of the avulsed meniscal root, applicable to both the medial or lateral menisci. Our technique utilizes a novel retrograde reaming device to create a small intraosseous socket at the meniscal tibial attachment, and may be particularly useful for repairing meniscal root avulsions in knees with multiligamentous injuries.     

Contribution of thin-slice (1 mm) axial proton density MR images for identification and classification of meniscal tears: correlative study with arthroscopy

Objective To evaluate the diagnostic efficacy of thin-slice (1 mm) axial proton density-weighted (PDW) MRI of the knee for meniscal tear detection and classification. Methods We prospectively assessed pre-operative MR images of 58 patients (41 males, 17 females; age range 18-62 years) with arthroscopically confirmed meniscal tear. First, we evaluated the performance of the sagittal and thin-slice axial MR images for the diagnosis of meniscal tears. Second, we compared the correlation of tear types presumed from sagittal and axial MRI with arthroscopy and tear classification from axial MRI. Tears were classified on the sagittal plane and the axial plane separately. The diagnostic performance and tear classification were compared statistically with arthroscopy results, which is accepted as the standard of reference. Results 8 of 58 patients were removed from the study group because they had complex or degenerative tears. A total of 62 tears were detected with arthroscopy in 50 patients. On the sagittal images, sensitivity and specificity values were 90.62% and 70.37%, respectively, for medial meniscus tears and 72.73% and 77.14%, respectively, for lateral meniscus tears. The corresponding values for axial images were 97.30% and 84.00%, respectively, for medial meniscus tears and 95.65% and 80.50%, respectively, for lateral meniscus tears. There was no significant difference in tear classification between the arthroscopy results and the thin-slice axial PDW MRI results (p>0.05). Conclusion thin-slice axial PDW MRI increases the sensitivity and specificity of meniscal tear detection and especially classification, which is important for surgical procedure decisions.     

Pitfalls in MR imaging of the knee

Discrepancies between the findings of magnetic resonance (MR) imaging and those of arthroscopy were reviewed retrospectively in 52 knee examinations. Some of the discrepancies between MR imaging and arthroscopy were caused by errors in interpretation of MR images due to normal structures that mimicked meniscal tears. The transverse ligament and the lateral inferior genicular artery can produce the appearance of tears in the anterior horns of the medial and lateral menisci, respectively. The popliteus tendon may be mistaken for a tear in the posterior horn of the lateral meniscus. The normal concavity at the outer edge of the meniscus can create a volume-averaging artifact, which mimics a horizontal tear in the meniscus. Tears of the meniscus and separations of the meniscus from the joint capsule were not seen or were underestimated when the tears were oriented parallel to the plane of the image. An awareness of these pitfalls may improve the accuracy of the interpretation of MR images of the knee.     

Meniscal repair using the inside-out suture technique

Operations to treat meniscal injuries rank among the most frequent procedures performed by orthopedic surgeons. Ongoing research into the natural history, basic science, and biomechanics of meniscal injury has highlighted the importance of preserving the meniscus to maintain normal knee biomechanics and function. The arthroscopic inside-out suture repair is currently the gold standard by which other meniscal repair techniques are judged. Although it is difficult to identify meniscal tears amenable to repair preoperatively, an assessment of patient factors and tear characteristics on the basis of magnetic resonance imaging and intraoperative findings will aid the decision to excise or repair. For successful repair the meniscal tear must have appropriate location and characteristics, without evidence of fraying or degeneration. Repair with the arthroscopic inside-out method affords anatomic reduction of the meniscus tear and allows stimulation of circulation, factors which contribute to healing of the repair. Coupled with careful dissection and needle placement, this method minimizes complications associated with meniscus repair.     

膝关节半月板后根部撕裂的MRI评价

目的 探讨MRI对膝关节半月板后根部撕裂的价值.方法 回顾分析经关节镜证实的30例半月板后根部撕裂患者(17例累及内侧半月板,13例累及外侧半月板)的MRI表现,分析MRI对半月板后根部撕裂的诊断敏感度,MRI对内侧、外侧半月板后根部撕裂的检出比例比较采用Fisher确切概率法检验.结果 30例半月板后根部撕裂患者中,MRI正确诊断26例(包括17例内侧半月板后根部撕裂和9例外侧半月板后根部撕裂),诊断敏感度为86.7%(26/30).半月板后根部撕裂的MRI表现主要为后根部形态失常,代之以异常高信号影.MRI对内侧半月板后根部撕裂的检出比例(17/17)明显高于外侧(9/13)(P=0.026).内侧半月板后根部撕裂合并半月板脱位的发生比例(15/17)明显高于外侧(6/13)(P=0.020),但并发前交叉韧带损伤的发生比例(5/17)则明显低于外侧(11/13)(P=0.004).结论 MRI是诊断半月板后根部撕裂及伴发损伤的较好方法.     

Radiological classification of meniscocapsular tears of the anterolateral portion of the lateral meniscus of the knee

In an arthroscopic-MRI correlation study of acute injuries to the knee it was found that anterolateral meniscocapsular separations of the lateral aspect of the knee were missed on MRI reporting. Eighty sports-related injuries of the knee were seen by experienced orthopaedic surgeons at the University of Malaya Medical Centre and at the National Sports Centre, Malaysia from January 1996 to July 1997. Fifty of the patients were suspected to have meniscal tears that were either lateral or medial on clinical examination and they were sent for MRI. Many of these patients were tertiary referrals. Magnetic resonance imaging examinations in 27 of the 50 patients were reported as not showing any intrasubstance or obvious meniscocapsular tears, but arthroscopy performed on them revealed anterolateral meniscocapsular tears of the lateral meniscus of varying degrees in nine of these patients. In retrospect the tears could be seen on MRI, and a pattern to the tears was noted and classified as follows. Type 0, normal; type 1, torn inferior or superior meniscocapsular attachment; type 2, both meniscofemoral and meniscotibial ligaments torn but with minimal separation of meniscus and capsule by fluid or synovitis; and type 3, marked separation of meniscus and capsule by fluid (> 3 mm). Ten patients who did not undergo arthroscopy for various personal and financial reasons underwent MRI which showed type 1 and type 2 tears, and were treated conservatively. These patients were all asymptomatic after 4-6 weeks with regard to clinical signs, suggesting a lateral meniscal tear. Magnetic resonance imaging therefore does reveal minor degrees of meniscocapsular tears anterolaterally when one understands the normal anatomy in this region.     

Marginal fractures of the medial tibial plateau: possible association with medial meniscal root tear

We report two cases of marginal fractures of the medial tibial plateau associated with medial meniscal root tears. Both patients sustained knee dislocations, with complete tears of the posterior horn medial meniscal root. One sustained a “reverse Segond fracture”; the other sustained an “anteromedial impingement fracture” of the tibial plateau. The meniscal root tears were arthroscopically confirmed and repaired. In the first patient, the integrity of the meniscal root repair was confirmed at a 6-month follow-up arthroscopy for lysis of adhesions. In the second patient, follow-up MRI at 10 months demonstrated a healed meniscal root. The association of medial meniscal root tear with marginal fractures of the medial tibial plateau has not been previously reported.     

外侧半月板腘肌腱区损伤的缝合方法

目的介绍一种经前方关节镜入路进行全关节内半月板缝合的手术技术,探讨外侧半月板腘肌腱区安全、有效的修补方法。方法2002年7月至2006年5月,共采用经前方入路的全内缝合技术修补外侧半月板腘肌腱区损伤36例,其中合并前交叉韧带损伤26例,单纯桶柄样撕裂2例,盘状软骨损伤8例。常规关节镜前内及前外侧入路,缝合时关节镜置于前外侧入路,前内侧入路为缝合通道。膝关节屈曲90°位内翻,呈“4”字位。将预装配可吸收缝线的缝合钩通过前内侧入路置入关节内,在腘肌腱两侧分别进行缝合,关节内完成垂直褥式缝合、过线、打结、剪线的全部操作步骤。合并前交叉韧带损伤者同时行韧带重建手术,具备修补性的盘状软骨损伤者在修补术之前进行成形术。结果其中30例得到随访,平均随访25.8个月。采用临床检查及二次手术探查对半月板愈合状况进行综合评估。30例可随访病例全部进行了临床检查,均属于“无症状”,其中26例进行了二次手术探查,结果25例完全愈合,1例部分愈合,未发现不愈合病例。无明显手术并发症出现。结论经前方关节镜入路的全关节内缝合技术修补外侧半月板腘肌腱区损伤,可以达到牢靠的缝合效果,有效地避免损伤腘肌腱及腓总神经,获得较好的临床疗效。     

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。     

Effect of chondrocalcinosis on the MR imaging of knee menisci

OBJECTIVE: Our goal was to determine the influence of chondrocalcinosis on MR imaging in the detection of meniscal tears. MATERIALS AND METHODS: A retrospective review was performed of knee MR imaging and arthroscopy records from two university hospitals between 1996 and 1998. Seventy individuals had radiographic evidence of chondrocalcinosis and underwent knee MR imaging. Thirty-seven of these individuals had undergone arthroscopy for further evaluation of their symptoms. MR imaging sensitivity and specificity in the detection of medial and lateral meniscal tears were calculated in these 37 patients who had radiographic evidence of chondrocalcinosis and in a control group of 34 patients who underwent MR imaging and arthroscopy but did not have knee chondrocalcinosis. RESULTS: In the chondrocalcinosis group, MR imaging sensitivity, specificity, and accuracy for meniscal tear were 78%, 71%, and 78%, respectively, for the lateral meniscus, and 89%, 72%, and 81% for the medial meniscus. The control group showed sensitivity, specificity, and accuracy of 93%, 100%, and 97%, respectively, for the lateral meniscus and 100% in all cases for the medial meniscus. The MR imaging detection of meniscal tears in both the lateral and medial compartments combined is significantly poorer in the presence of chondrocalcinosis (p < 0.005). CONCLUSION: MR imaging sensitivity and specificity for detection of meniscal tear is decreased in the presence of meniscal chondrocalcinosis. Chondrocalcinosis appeared as a high-signal-intensity region on T1-weighted, intermediate-weighted, and inversion recovery sequences. The high signal of chondrocalcinosis on inversion recovery sequence is an interesting observation that to our knowledge has not been previously reported. Radiographic correlation with the MR imaging examination can help prevent overdiagnosing meniscal tears.     

MR of the knee: the significance of high signal in the meniscus that does not clearly extend to the surface

On MR images of the knee it is sometimes impossible to determine with confidence if a focus of high signal in the meniscus is confined to the substance of the meniscus or if it extends to involve the surface. This is a critical differentiation because the latter represents meniscal tears that can be found and treated at arthroscopy, whereas the former represents degeneration, tears, or perhaps normal variants that cannot be detected or treated arthroscopically. We make an equivocal diagnosis of a tear when it is difficult to decide if signal in a meniscus involves the meniscal surface. We studied MR scans of the knee in 142 consecutive patients for the presence of such equivocal tears. Their prevalence was 14% (20/142); 17 were in the posterior horn of the lateral meniscus and three were in the posterior horn of the medial meniscus. In 13 cases with arthroscopy/arthrotomy correlation, no tears were found. In one of the 20 patients in whom the meniscus was removed during arthroplasty, histologic examination of the meniscus showed separation of collagen bundles, which was caused by meniscal degeneration confined to the substance of the meniscus. These results suggest that a meniscal tear is unlikely when MR scans show a focus of high signal in a meniscus that does not unequivocally extend to involve the surface of the meniscus.     

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)     

Meniscal tears: role of axial MRI alone and in combination with other imaging planes

OBJECTIVE: The purpose of this study was to determine the reliability of standard axial MR images alone in the diagnosis of meniscal tears of the knee and in combination with other imaging planes. MATERIALS AND METHODS: Sixty-two patients (55 men, seven women; age range, 23-68 years) with a prior MRI examination who underwent arthroscopic surgery of the knee during a 1-year period were included in the study group. Images were independently reviewed for identification of meniscal tears by two musculoskeletal radiologists blinded to arthroscopic findings. Sequences for meniscal evaluation included axial fat-saturated fast spin-echo proton density, coronal fat-saturated fast spin-echo proton density, and sagittal fast spin-echo proton density with 4- to 5-mm slice thicknesses. Imaging groups for evaluation were axial, coronal, sagittal, axial and sagittal, axial and coronal, and coronal and sagittal. Observers reported a confidence level for the presence or absence of meniscal tear in all imaging groups based on a 5-point scale. Statistical analysis considered medial and lateral menisci separately. RESULTS: Forty patients had medial meniscal tears, and 16 had lateral meniscal tears at arthroscopy. For medial and lateral meniscal tears, the accuracy (79% and 71%, respectively) of imaging in the axial plane was comparable to other imaging groups but the mean confidence levels (2.82 and 3.00, respectively) were low. In one patient, the axial plane alone correctly showed that no tear was present. No statistically significant difference was observed between imaging plane groups of both menisci in the diagnosis of meniscal tears (p > 0.05). The axial plane increased the accuracy of sagittal and coronal planes of lateral meniscus when combined. CONCLUSION: In standard knee MRI examinations, the axial imaging plane may be valuable for the detection and characterization of meniscal tears.