Posterior double PCL sign: a case report of unusual MRI finding of bucket-handle tear of medial meniscus

Among the MRI signs of bucket-handle tears of medial meniscus, double posterior cruciate ligament (PCL) sign denotes a low signal band anterior and parallel to the PCL, which looks like another PCL in MR images. If the bucket-handle fragment subsequently tears at the anterior horn, the torn meniscal substance can be displaced to the posterosuperior region of the PCL, and looks like another PCL behind the original PCL. We propose the lesion be called the “posterior double PCL sign” in contrast to the ordinary double PCL sign. We present a case showing the posterior double PCL sign.     

Double PCL sign does not always indicate a bucket-handle tear of medial meniscus

The discoid medial meniscus is an extremely rare anomaly. Bilateral discoid medial menisci are much more rare but intermittently reported. We report the first case of bilateral discoid medial menisci with positive double PCL sign, which typically indicates a bucket-handle tear of medial meniscus. A literature review was also conducted on bilateral discoid medial menisci. Level of evidence IV.     

MR imaging of displaced bucket-handle tear of the medial meniscus

A bucket-handle tear of the meniscus is a vertical or oblique tear with longitudinal extension toward the anterior horn in which the inner fragment is frequently displaced toward the intercondylar notch with resultant mechanical locking of the knee joint. A precise MR diagnosis requires identification of the centrally displaced fragment because the peripheral nondisplaced component may have only a subtle truncated or foreshortened appearance that may escape detection. Eighteen consecutive cases of displaced bucket-handle tears of the medial meniscus diagnosed by MR had a characteristic low-signal band extending across the joint and projecting over the medial tibial eminence. The posterior portion was parallel and beneath the posterior cruciate ligament on both sagittal and coronal images. Arthroscopy confirmed the presence and location of the displaced fragment in all 18 cases. Awareness of this characteristic MR finding may increase the sensitivity of MR imaging in the diagnosis of bucket-handle tears of the medial meniscus.     

Distraction forces on repaired bucket-handle lesions in the medial meniscus

BACKGROUND: Numerous studies have investigated the biomechanical properties of meniscal repair techniques. One of the most commonly discussed parameters is the failure load in the axis of insertion, although little is known about the distraction forces actually occurring at repaired bucket-handle lesions. HYPOTHESIS: There are clinically relevant distraction forces on repaired meniscus bucket-handle lesions. STUDY DESIGN: Controlled laboratory study. METHODS: Meniscus bucket-handle lesions were created and repaired in human cadaveric knees with a vertical suture made from a braided steel wire. A small-sized load sensor was connected to the wire at the periphery of the meniscus. The distraction forces acting on the lesion were measured at different knee joint angles (0 degrees -120 degrees of flexion) with internal and external rotation and with and without weight loading. Forces in excess of 10 N were considered to have clinical relevance. RESULTS: Mean forces on the meniscus repair ranged from 1.64 to 4.72 N. Irrespective of the modalities (ie, different flexion angles, weight load, direction of rotation), it was found that the forces were well below the cutoff value of 10 N (P < .01). Increasing flexion angles generally did not cause an increase in distraction forces. CONCLUSION: The data suggest that distraction forces are not the primary factor in the mechanical stability of meniscal repair. It must therefore be assumed that other factors such as shear forces are of greater significance. CLINICAL RELEVANCE: The results may help to validate the biomechanical properties of different meniscal repair techniques.     

The quadruple cruciate sign of simultaneous bicompartmental medial and lateral bucket-handle meniscal tears

We report the second known case of bicompartmental bucket-handle tears of the medial and lateral menisci and the first documented case of the bucket-handle tears occurring simultaneously following trauma, which occurred after a motorcycle accident. Both bucket-handle fragments were displaced into the intercondylar notch. An anterior cruciate ligament tear was also present. Coronal images demonstrated four structures in the intercondylar notch: the anterior and posterior cruciate ligaments and the medial and lateral bucket-handle meniscal fragments.     

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.     

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.     

Non-operative treatment of degenerative posterior root tear of the medial meniscus

We reviewed thirty patients with degenerative posterior root tear of the medial meniscus to investigate clinical results of non-operative treatment retrospectively. There were 3 men and 27 women at a median age of 59 years old (range, 51–65). The median follow-up period was 36 months (range, 24–51). Non-operative treatments included non-steroidal anti-inflammatory drugs daily for 8–12 weeks and supervised physical therapy twice a week at least during a period of 8 weeks. The symptoms, physical signs, the Visual Analog Scale pain, the Lysholm Knee Scoring scale and IKDC subjective activity level were analyzed at the time of pre-intervention, 6 months, 12 months and the final follow-ups. Most patients had intense mechanical pain initially, but the severity and frequency of pain was decreased within 3 months. Clinical outcome was improved at 12 months follow-up and then declined to a level that was still improved over initial scores at final follow-up. Two patients with Kellgren–Lawrence grade 2 progressed to grade 3 at the median follow-up of 36 months. In conclusion, this study demonstrated that non-operative treatment provided symptomatic relief in most patients with the degenerative posterior root tear of the medial meniscus and functional improvements in a short term follow-up.     

Wrisberg variant of the discoid lateral meniscus with flipped meniscal fragments simulating bucket-handle tear: MRI and arthroscopic correlation

An MRI diagnosis of the Wrisberg variant discoid lateral meniscus should be considered in patients presenting with an anteriorly flipped posterior horn fragment without a definable peripheral rim. We present four cases discovered on arthroscopy that were thought to resemble bucket-handle tears on preoperative MRI. Posterior hypermobility poses a surgical challenge as excessive debridement without careful attention to underlying meniscal morphology may lead to further instability. Although this diagnosis can be difficult to make on MRI, alerting the orthopedic surgeon preoperatively may influence repair technique and meniscus conservation.     

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.     

The flipped meniscus sign

Meniscal fragments may be difficult to detect on magnetic resonance (MR) imaging and yet are clinically significant. This paper describes and illustrates the MR appearance of an easily overlooked meniscal fragment. Ten knees, each appearing to show an abnormally large anterior meniscal horn (8 mm or more in height) were prospectively identified on MR images. In each case demonstrable large tears of the ipsilateral posterior horns were present (same meniscus as had large anterior horns). The lateral meniscus was involved in nine cases and the medial in one. Two of the ten patients imaged had surgically proven bucket-handle meniscal tears as well as meniscal fragments overlying the ipsilateral anterior horn. In one case previous MR imaging at our institution had demonstrated the affected anterior horn to be of normal caliber. The striking MR appearance of an abnormally enlarged anterior meniscal horn in association with a tear of the ipsilateral posterior horn suggests the presence of a meniscal fragment or of a posteriorly detached bucket-handle tear of the posterior horn of the meniscus.Presented at the Fifteenth Annual Skeletal Symposium of the Hospital of the University of Pennsylvania at Sun Valley, Idaho, USA, on 3 March 1992     

Larger medial femoral to tibial condylar dimension may trigger posterior root tear of medial meniscus

Purpose

The major meniscal functions are load bearing, load distribution, and shock absorption by increasing the tibiofemoral joint (TFJ) contact area and dissipating axial loads by conversion into hoop stresses. The increased hoop strain stretches the meniscus in outward direction towards radius, causing extrusion, which is associated with the root tear and resultant degenerative osteoarthritis. Since the larger contact area of medial TFJ may increase the hoop stresses, we hypothesized that the larger medial femoral to tibial condylar dimension would contribute to the development of medial meniscus posterior root tear (MMPRT). Thus, the purpose of the study was to assess the relationship between MMPRT and medial femoral to tibial condylar dimension.

Methods

A case–control study was conducted to compare medial femoral to tibial condylar dimensions of patients with complete MMPRT (n = 59) with those of demography-matched controls (n = 59) during the period from 2010 to 2013. In each patient, MRIs were reviewed and several parameters were measured including articulation width of medial femoral condyle (MFC) at 0°, 30°, 60°, and 90°, medial tibial condyle (MTC) width, degree of meniscal extrusion, and medial femoral to tibial condylar width ratio (MFC/MTC) at 0°, 30°, 60°, and 90°, respectively. Demographic and radiographic data were assessed.

Results

A larger medial femoral to tibial condylar dimension was associated with MMPRT at 0° and 30° knee angles. Patients with MFC/MTC greater than 0.9 at 0° also showed about 2.5-fold increase in the chance of MMPRT. Those with meniscal extrusion greater than 3 mm also had about 17.1 times greater chance for the presence of MMPRT accordingly.

Conclusions

A larger medial femoral to tibial condylar dimension may be considered as one of the regional contributors to the outbreak of MMPRT, and medial femoral to tibial condylar width ratio greater than 0.9 at 0° knee angle may be considered as a significant risk factor for MMPRT.

Level of evidence

III.

     

Digital radiographic evaluation of medial joint space narrowing after partial meniscectomy of bucket-handle medial meniscus tears in anterior cruciate ligament-intact knees

BACKGROUND: Few studies exist that evaluate the effect of partial medial meniscectomy in knees with intact anterior cruciate ligaments. HYPOTHESIS: Partial meniscectomy of bucket-handle medial meniscus tears will cause joint space narrowing. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Between 1982 and 2001, 135 patients met the study criteria of a partial medial meniscectomy, intact ligaments, no surgery to the contralateral knee, and no chondromalacia greater than grade II. Seventy-nine patients living within 150 miles of the clinic were asked to return for physical examination. Joint space narrowing was measured from the middle of the femoral condyle to the middle of the tibial plateau using digitally magnified weightbearing 45 degrees flexed posteroanterior and full-extension anteroposterior radiographs. Measurements were performed twice with the observer blinded to the previous measurements. Subjective follow-up was obtained prospectively on an annual basis with International Knee Documentation Committee and modified Noyes knee questionnaires. RESULTS: Forty-nine patients were examined at a mean of 11.8 years postoperatively. Mean medial joint space narrowing was 1.2 +/- 0.5 mm on 45 degrees flexed posteroanterior radiograph and 0.2 +/- 0.9 mm on full-extension anteroposterior radiographs (P < .001). Four patients had 2 mm or more of joint space narrowing. Subjective surveys obtained from 95 patients showed a mean subjective score of 89.9 points. Subjective scores did not decrease through time, and there was no correlation of joint space narrowing to lower subjective scores. CONCLUSION: Partial medial meniscectomy in stable knees causes only mild joint space narrowing (mean, 1.2 mm) at a mean 12-year follow-up. Digitally magnified 45 degrees flexed posteroanterior radiographs are more likely to demonstrate joint space narrowing than are full-extension anteroposterior radiographs.     

Arthroscopic pullout repair of posterior root tear of the medial meniscus: the anterior approach using medial collateral ligament pie-crusting release

Posterior root tears of the medial meniscus are frequently encountered and should be repaired if possible to prevent osteoarthritis of the medial compartment. Various surgical techniques have been proposed to repair posterior root tears. The anterior arthroscopic approach can cause an iatrogenic chondral injury due to the narrow medial joint space. The posterior approaches might be technically unfamiliar to many surgeons because they require the establishment of a posteromedial or trans-septal portal. This paper describes the medial collateral ligament pie-crusting release technique for arthroscopic double transosseous pullout repair of posterior root tears of the medial meniscus through the anterior approach to provide the good visualization of the footprint and sufficient working space.