Posterior Meniscus Research Articles

Avulsion of the anterior medial meniscus root: case report and surgical technique

Injuries of the meniscus roots have become increasingly recognised as a serious pathology of the knee joint. However, the current available literature focuses primarily on posterior meniscus root tears. In this article, a case with an isolated avulsion of the anterior medial meniscus root is presented, and a new arthroscopic technique to treat this type of injury is described. The anterior horn of the medial meniscus was sutured with a double-looped nonabsorbable suture and reattached to the tibial plateau using a knotless suture anchor. This technique may also be useful to treat avulsion injuries of the anterolateral or posteromedial meniscus root, and symptomatic subluxation of the medial meniscus in case of a variant insertion anatomy with an absent attachment of the anterior horn of the medial meniscus to the tibial plateau. Level of evidence V.

Posterior root tear fixation of the lateral meniscus combined with arthroscopic ACL double-bundle reconstruction: technical note of a transosseous fixation using the tibial PL tunnel

According to our observation in ACL reconstruction, we find root tears of the posterior horn of the lateral meniscus as a common concomitant injury in ACL-deficient knees. This might be a consequence of initial trauma or of the increased anterior-posterior translation of the tibia and an overload impact on the posterior meniscus root in ACL-deficient knees. A tear of the posterior horn of the medial meniscus causes a 25% increase in peak pressure in the medial compartment compared with that found in the intact condition. The repair restores the peak contact pressure to normal (Allaire et al. in J Bone Joint Surg Am 90(9):1922-1931, [2008]). A tear of the posterior horn of the lateral meniscus might have similar consequences. We hypothesize the surgical anatomical reattachment of the root at the tibia helping to restore knee joint kinematics and helping to advance ACL-graft function. This article presents an arthroscopical technique to reattach the posterior meniscus root in combination with ACL double-bundle reconstruction. The procedure uses the tibial PL tunnel to fix the meniscus suture.

MRI evaluation of the posterior meniscus root tear

：Objective To determinethe value of MRI for diagnosing the posterior meniscus root tear. Methods MR examinationsof 30 patients with tear of the posterior meniscus root confirmed by knee arthroscopieswere retrospectively reviewed. Of the 30 patients, 17 with posterior medial meniscus roottear (MMRT) and 13 with posterior lateral meniscus root tear (LMRT). The diagnosticsensitivity of MRI for the posterior meniscus root tear was analyzed. Fisher's exact testwas used to compare the detection rate of MRI for MMRT with that for LMRT. Results All 17cases with MMRT and 9 cases out of 13 with LMRT were correctly diagnosed by MRI and thediagnostic sensitivity of MRI for the posterior meniscus root tear was 86. 7% (26/30). Themain MR appearance of the posterior meniscus root tear was distortion of the meniscalroot, with its low signal replaced by abnormal high signal. The detection rate of MRI forMMRT (17/17)was significantly greater than that for LMRT (9/13) ( P =0. 026). Theprevalence of MMRT associated with meniscus extrusion ( 15/17 ) was significantly greaterthan that of LM RT ( 6/13 ) ( P = 0. 020), but the prevalence of MMRT associated withanterior cruciate ligament (ACL) injury (5/17) was significantly lower than that of LMRT(11/13) (P = 0. 004). Conclusion MRI is a relatively good method for detection ofposterior meniscus root tears and associated injuries.

Differential MMP-2 activity induced by mechanical compression and inflammatory factors in human synoviocytes.

The anterior cruciate ligament, posterior cruciate ligament, cartilage and meniscus in human knee joint have poor healing ability. Accumulation of MMPs in the joint fluids due to knee injury has been considered as the main reason. Our previous experiments showed that synovium may be the major regulator of MMPs in joint cavity after injury. In this paper, we used human synoviocytes harvested from synovium to determine whether mechanical injury and inflammatory factors will induce MMP-2 production in synoviocytes. With zymography, we found that mechanical compression increased the MMP-2 production by 23% under 6% compressions, 61% under 12% compression and 109% under 14% compressions. In addition, TNF-alpha can also elevate the activity of MMP-2 in a dose dependent manner, while IL-1alpha does not. However, mixture of these two factors dramatically increased MMP-2 production by 201%. In addition, mechanical injury had a strong synergistic effect on MMP-2 production with TNF-alpha, IL-1alpha and their mixture, increasing by 207%, 354% and 468% individually. The generic MMP activity assayrevealed that mechanical compression increased the generic activity. APMA treatment increased the generic activity of MMPs induced by compres-

An 11-Year-Old Girl Presenting with Chronic Knee Pain: A Case Report with Diagnostic Dilemma

Discoid meniscus is the commonest anatomical aberration of the knee joint, among rare cases such as bilateral separated lateral meniscus, accessory lateral meniscus, partial deficiency of the lateral meniscus and double-layered lateral meniscus. An 11-year-old girl presented with history of chronic pain in her right knee for the last 6 months. The problem disturbed her involvement in the sport activities at school. Clinical examination revealed a clicking sensation on knee extension with lateral joint line tenderness. Magnetic resonance imaging (MRI) of her right knee showed torn posterior horn of lateral meniscus. Arthroscopy examination revealed a discoid meniscus with absence posterior horn. Posterior horn deficient discoid meniscus is a rare form of a congenital meniscus anomaly. We as clinicians believe that the abnormal shaped meniscus may pose a diagnostic challenge clinically and radiologically. Presentation of this case may be beneficial for orthopaedicians in their daily clinical practice.

Coordinated Expression of MMPs and TIMPs in Rat Knee Intra-Articular Tissues After ACL Injury

Anterior cruciate ligament (ACL) has poor healing ability and an injured ACL would induce the degeneration of other intra-articular connective tissues. However, the coordinated expression and activities of matrix metalloproteinase (MMPs) in intra-articular tissues induced by ACL rupture were poorly understood. With a rat ACL rotating injury model, we found that after ACL injury, the mRNA levels of MMP-13, TIMP-1, and CD147 were significantly elevated in ACL, posterior cruciate ligament (PCL), synovium, meniscus, and cartilage. Also, MMP-2 activity was also elevated significantly in a time-dependent manner in all intra-articular tissues. Synovium showed the most capability to release MMPs, whereas ACL showed the highest MMP-13/TIMP-1 ratio. Generic MMP activity assay and zymography showed time dependent elevation of MMP activities in synovial fluids (SF). We concluded that the ACL injury would induce a coordinated response of intra-articular tissues to express MMPs, TIMPs, and CD147. The MMP activities in the microenvironment in SF would accumulate, released by all the intra-articular tissues, which would contribute to the knee damage and degeneration induced by ACL injury.

Delayed gadolinium‐enhanced magnetic resonance imaging of the meniscus: An index of meniscal tissue degeneration?

Much attention has been focused recently on the need for a better understanding of the mechanisms and natural progression of knee osteoarthritis (OA), particularly in its early stages. One technique that has been used to investigate early OA is delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC), where T1(Gd) (T1 value after penetration of the MRI contrast agent gadopentate dimeglumine [Gd-DTPA(2-)]) is used as an index of the molecular status of articular cartilage. The goal of this study was to explore T1(Gd) in the meniscus and its relationship with articular cartilage T1(Gd) in knee dGEMRIC image data sets. T1(Gd) maps of the meniscus and articular cartilage were made from knee dGEMRIC images obtained from prior studies of dGEMRIC of the knee in 21 asymptomatic subjects and 9 patients with self-reported OA. T1(Gd) of the meniscus covered a range of values (247-515 msec) and patterns (homogeneous and focal variations). In addition, T1(Gd) of the meniscus correlated with that of articular cartilage (R = 0.38, P = 0.037; R = 0.57, P = 0.001 for correlations of the medial posterior meniscus with the medial femoral and tibial cartilage, respectively; T1[Gd] of the anterior meniscus and lateral compartments also correlated, with R > 0.38 and P < 0.037), potentially demonstrating parallel degradative processes in the knee. While the biophysical basis for the T1(Gd) results relative to meniscus molecular structure needs investigation, these findings introduce a potential means of examining the time course of meniscal tissue change in the development and progression of arthritis.

Knee immobilization on meniscal healing after suture: an experimental study in sheep.

Immobilization and nonweightbearing may influence the healing of sutured meniscal lesions in the avascular zone. In 12 sheep, 3 to 4 months of age, a 0.5-cm longitudinal lesion was made in the middle segment and posterior portion of the medial meniscus of the left knee in the avascular zone. The lesion was sutured immediately. The knees of six sheep were immobilized with a monolateral external fixator, which crossed the knee, and the knees in the other six sheep were not immobilized. The animals were sacrificed 6 weeks after the operation. Specimens from the anterior meniscus were used for histologic and vascular studies, and the posterior meniscus was used for mechanical testing. Repair was observed in two of 12 sheep in the form of fibrous tissue. Fibrochondrocytes and synovial cells were involved. Meniscal fibrochondrocytes from the nearest meniscal tissue, synovial cells from the femoral and tibial meniscal surfaces, and fibroblastic cells migrating through the suture channel provide cell access to the meniscus lesion. Sutured menisci, immobilized or not, support less than 50% of a normal load and are mechanically weak.

KNEE PAIN - MENISCUS TEAR 829

HISTORY - A 23-year-old senior male basketball player for a Division I university landed after an attempted blocked shot and felt intense pain over the posterior-lateral aspect of his knee. He did not feel a pop or have complaints of instability. He had no previous history of knee pain or injury. The fifth year senior wanted to complete his final season if possible. PHYSICAL EXAM - The athlete was evaluated at courtside by the athletic trainer and in the training room by the team physician. His primary complaint was of pain and inability to fully extend his knee. Range of motion was 15°-60° limited by pain. No gross effusion was present. He was focally tender over the posterior lateral joint line. Ligamentous stability appeared to be intact with a negative Lachman's, negative posterior sag, negative external rotation recurvatum, and negative laxity to varus and valgus stress at 0° and 30°. McMurray's examination instituted pain laterally but was not complete secondary to limited range of motion. DIFFERENTIAL DIAGNOSIS: Lateral meniscus tear, 2. Posterior-lateral complex injury, 3. Popliteal tendon rupture, 4. Lateral collateral ligament strain, 5. Fracture or bone bruise. TEST AND RESULTS: Plain radiographs were negative for fracture or bony pathology. Magnetic resonance imaging revealed a peripheral tear of the entire posterior horn of the lateral meniscus and Grade I changes in the lateral collateral ligament and posterior lateral complex. FINAL DIAGNOSIS: After review of the test results with the athlete, his family, and his athletic trainer, he was taken to surgery for arthroscopy of his knee. A large bucket handle tear of his posterior meniscus was identified locked in the intercondylar notch. The unstable fragment comprised 60-70% of his entire meniscus and 100% of his posterior horn. Meniscal repair was selected over meniscectomy due to the peripheral nature and overwhelming size of the tear. An accelerated aggressive rehabilitation allowing full weight-bearing and full range of motion immediately was instituted. However, he was restricted from twisting and cutting activities for two months. TREATMENT: While meniscus tears are not an uncommon injury in elite athletes, they do present a difficult dilemma in recommendation and treatment options for coaches, athletic trainers, team physicians, and orthopaedic surgeons. This case notes an athlete playing in his final collegiate season who is an important cog in his team's success. The player, coach, athletic trainer, and physician all would like to have the athlete back as soon as possible which would imply partial meniscectomy. Nonetheless, due to the likelihood of early degenerative arthritis with a nearly complete meniscectomy, a meniscal repair with its associated longer rehabilitation would best serve this patient in the long run.

Inframeniscal Approach for Arthroscopic Resection of Tears of the Posterior One-third of the Medial Meniscus

Arthroscopic resection of tears of the posterior third of the medial meniscus may be difficult. Meniscectomy by use of routine portals superior to the meniscus is difficult in knees in which valgus stress does not allow access to the posterior meniscus. The operation may be facilitated by the use of portals inferior to the meniscus. This inframeniscal approach avoids the problem of excessive scuffing, possible medial collateral ligament sprain, and the need for a posterior medial portal.

Arthrography of the lateral meniscus.

Double contrast arthrography can be utilized to assess the anatomic shape and movement of the lateral meniscus. The area of primary importance appears to be where the popliteus bursa crosses the posterior meniscus. Pathological conditions such as peripheral separation of the meniscus, cystic degeneration of the meniscus and the discoid lateral meniscus have characteristic radiographic findings involving the meniscus posteriorly at either its peripheral or central attachments.