Original Article|Articles in Press

Isolated Posterior Lateral Meniscofemoral Ligament Tears Show Greater Meniscal Extrusion in Knee Extension, and Isolated Posterior Lateral Meniscal Root Tears Show Greater Meniscal Extrusion at 30° Using Ultrasound: A Cadaveric Study

Published:February 20, 2023DOI:


      To quantify the effects that posterior meniscofemoral ligament (pMFL) lesions have on lateral meniscal extrusion (ME) both with and without concomitant posterior lateral meniscal root (PLMR) tears and describe how lateral ME varied along the length of the lateral meniscus.


      Ultrasonography was used to measure ME of human cadaveric knees (n = 10) under the following conditions: control, isolated pMFL sectioning, isolated PLMR sectioning, pMFL+PLMR sectioning, and PLMR repair. ME was measured anterior to the fibular collateral ligament (FCL), at the FCL, and posterior to the FCL in both unloaded and axially loaded states at 0° and 30° of flexion.


      Isolated and combined pMFL and PLMR sectioning consistently demonstrated significantly greater ME when measured posterior to the FCL compared with other image locations. Isolated pMFL tears demonstrated greater ME at 0° compared with 30° of flexion (P < .05), whereas isolated PLMR tears demonstrated greater ME at 30° compared with 0° of flexion (P < .001). All specimens with isolated PLMR deficiencies demonstrated greater than 2 mm of ME at 30° flexion, whereas only 20% of specimens did so at 0°. When the pMFL was sectioned following an isolated PLMR tear, there was a significant increase in ME at 0° (P < .001). PLMR repair after combined sectioning restored ME to levels similar to that of controls in all specimens when measured at and posterior to the FCL (P < .001).


      The pMFL protects against ME primarily in full extension, whereas the presence of ME in the setting of PLMR injuries may be better appreciated in knee flexion. With combined tears, isolated repair of the PLMR can restore near-native meniscus position.

      Clinical Relevance

      The stabilizing properties of intact pMFL may mask the presentation of PLMR tears and delay appropriate management. Additionally, the MFL is not routinely assessed during arthroscopy due to difficult visualization and access. Understanding the ME pattern of these pathologies in isolation and combination may improve detection rates so that the source of patients’ symptoms can be addressed to satisfaction.
      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to Arthroscopy
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Allen P.R.
        • Denham R.A.
        • Swan A.V.
        Late degenerative changes after meniscectomy. Factors affecting the knee after operation.
        J Bone Joint Surg Br. 1984; 66: 666-671
        • Fairbank T.J.
        Knee joint changes after meniscectomy.
        J Bone Joint Surg Br. 1948; 30B: 664-670
        • Fox A.J.S.
        • Bedi A.
        • Rodeo S.A.
        The basic science of human knee menisci: Structure, composition, and function.
        Sports Health. 2012; 4: 340-351
        • Forkel P.
        • Herbort M.
        • Sprenker F.
        • Metzlaff S.
        • Raschke M.
        • Petersen W.
        The biomechanical effect of a lateral meniscus posterior root tear with and without damage to the meniscofemoral ligament: Efficacy of different repair techniques.
        Arthroscopy. 2014; 30: 833-840
        • Gupte C.M.
        • Bull A.M.
        • Thomas R.D.
        • Amis A.A.
        A review of the function and biomechanics of the meniscofemoral ligaments.
        Arthroscopy. 2003; 19: 161-171
        • Yamamoto M.
        • Hirohata K.
        Anatomical study on the menisco-femoral ligaments of the knee.
        Kobe J Med Sci. 1991; 37: 209-226
        • Amadi H.O.
        • Gupte C.M.
        • Lie D.T.T.
        • McDermott I.D.
        • Amis A.A.
        • Bull A.M.J.
        A biomechanical study of the meniscofemoral ligaments and their contribution to contact pressure reduction in the knee.
        Knee Surg Sports Traumatol Arthrosc. 2008; 16: 1004-1008
        • Grood E.S.
        • Hefzy M.S.
        • Lindenfield T.N.
        Factors affecting the region of most isometric femoral attachments. Part I: The posterior cruciate ligament.
        Am J Sports Med. 1989; 17: 197-207
        • Moran C.J.
        • Poynton A.R.
        • Moran R.
        • Brien M.O.
        Analysis of meniscofemoral ligament tension during knee motion.
        Arthroscopy. 2006; 22: 362-366
        • Geeslin A.G.
        • Civitarese D.
        • Turnbull T.L.
        • Dornan G.J.
        • Fuso F.A.
        • LaPrade R.F.
        Influence of lateral meniscal posterior root avulsions and the meniscofemoral ligaments on tibiofemoral contact mechanics.
        Knee Surg Sports Traumatol Arthrosc. 2016; 24: 1469-1477
        • Krych A.J.
        • Bernard C.D.
        • Kennedy N.I.
        • et al.
        Medial versus lateral meniscus root tears: Is there a difference in injury presentation, treatment decisions, and surgical repair outcomes?.
        Arthroscopy. 2020; 36: 1135-1141
        • Brody J.M.
        • Lin H.M.
        • Hulstyn M.J.
        • Tung G.A.
        Lateral meniscus root tear and meniscus extrusion with anterior cruciate ligament tear.
        Radiology. 2006; 239: 805-810
        • Pula D.A.
        • Femia R.E.
        • Marzo J.M.
        • Bisson L.J.
        Are root avulsions of the lateral meniscus associated with extrusion at the time of acute anterior cruciate ligament injury? A case control study.
        Am J Sports Med. 2014; 42: 173-176
        • Friedman L.
        • Finlay K.
        • Jurriaans E.
        Ultrasound of the knee.
        Skelet Radiol. 2001; 30: 361-377
        • Karpinski K.
        • Diermeier T.
        • Willinger L.
        • Imhoff A.B.
        • Achtnich A.
        • Petersen W.
        No dynamic extrusion of the medial meniscus in ultrasound examination in patients with confirmed root tear lesion.
        Knee Surg Sports Traumatol Arthrosc. 2019; 27: 3311-3317
        • Park G.Y.
        • Kim J.M.
        • Lee S.M.
        • Lee M.Y.
        The value of ultrasonography in the detection of meniscal tears diagnosed by magnetic resonance imaging.
        Am J Phys Med Rehabil. 2008; 87: 14-20
        • Rowland G.
        • Mar D.
        • McIff T.
        • Nelson J.
        Evaluation of meniscal extrusion with posterior root disruption and repair using ultrasound.
        Knee. 2016; 23: 627-630
        • Nogueira-Barbosa M.H.
        • Gregio-Junior E.
        • Lorenzato M.M.
        • et al.
        Ultrasound assessment of medial meniscal extrusion: A validation study using MRI as reference standard.
        AJR Am J Roentgenol. 2015; 204: 584-588
        • Özdemir M.
        • Turan A.
        Correlation between medial meniscal extrusion determined by dynamic ultrasound and magnetic resonance imaging findings of medial-type knee osteoarthritis in patients with knee pain.
        J Ultrasound Med. 2019; 38: 2709-2719
        • Van Thiel G.
        • Frank R.
        • Gupta A.
        • et al.
        Biomechanical evaluation of a high tibial osteotomy with a meniscal transplant.
        J Knee Surg. 2011; 24: 45-54
        • Condron N.B.
        • Knapik D.M.
        • Gilat R.
        • et al.
        Concomitant meniscotibial ligament reconstruction decreases meniscal extrusion following medial meniscus allograft transplantation: A cadaveric analysis.
        Arthroscopy. 2022; 38: 3080-3089
        • Paletta G.A.
        • Crane D.M.
        • Konicek J.
        • et al.
        Surgical treatment of meniscal extrusion: A biomechanical study on the role of the medial meniscotibial ligaments with early clinical validation.
        Orthop J Sports Med. 2020; 8232596712093667
        • Daney B.T.
        • Aman Z.S.
        • Krob J.J.
        • et al.
        Utilization of transtibial centralization suture best minimizes extrusion and restores tibiofemoral contact mechanics for anatomic medial meniscal root repairs in a cadaveric model.
        Am J Sports Med. 2019; 47: 1591-1600
        • Chahla J.
        • Moulton S.G.
        • LaPrade C.M.
        • Dean C.S.
        • LaPrade R.F.
        Posterior meniscal root repair: the transtibial double tunnel pullout technique.
        Arthrosc Tech. 2016; 5: e291-e296
        • Lerer D.B.
        • Umans H.R.
        • Hu M.X.
        • Jones M.H.
        The role of meniscal root pathology and radial meniscal tear in medial meniscal extrusion.
        Skeletal Radiol. 2004; 33
        • Oppo K.
        • Leen E.
        • Angerson W.J.
        • Cooke T.G.
        • McArdle C.S.
        Doppler perfusion index: An interobserver and intraobserver reproducibility study.
        Radiology. 1998; 208: 453-457
        • Lourensz M.
        • Trost N.
        • Pianta M.
        MSK Imaging Tips and Tricks. MAGNETOM Flash.
        (Published February 1, 2012)
        • Cunningham J.B.
        • Gardner E.
        Power, effect and sample size using GPower: Practical issues for researchers and members of research ethics committees.
        Evidence Based Midwifery. 2007; 5: 132-136
        • Faul F.
        • Erdfelder E.
        • Lang A.G.
        • Buchner A.
        G∗Power 3: A flexible statistical power analysis program for the social, behavioral, and biomedical sciences.
        Behav Res Methods. 2007; 39: 175-191
        • Bao H.R.C.
        • Zhu D.
        • Gu G.S.
        • Gong H.
        The effect of complete radial lateral meniscus posterior root tear on the knee contact mechanics: A finite element analysis.
        J Orthop Sci. 2013; 18: 256-263
        • Svensson F.
        • Felson D.T.
        • Turkiewicz A.
        • et al.
        Scrutinizing the cut-off for “pathological” meniscal body extrusion on knee MRI.
        Eur Radiol. 2019; 29: 2616-2623
        • Liu Y.
        • Joseph G.B.
        • Foreman S.C.
        • et al.
        Determining a threshold of medial meniscal extrusion for prediction of knee pain and cartilage damage progression over 4 years: Data from the Osteoarthritis Initiative.
        AJR Am J Roentgenol. 2021; 216: 1318-1328
        • Muzaffar N.
        • Kirmani O.
        • Ahsan M.
        • Ahmad S.
        Meniscal extrusion in the knee: should only 3 mm extrusion be considered significant? An assessment by MRI and arthroscopy.
        Malays Orthop J. 2015; 9: 17-20
        • Kijima H.
        • Miyakoshi N.
        • Kasukawa Y.
        • et al.
        Cut-off value of medial meniscal extrusion for knee pain.
        Adv Orthop. 2017; 20176793026
        • Crema M.D.
        • Roemer F.W.
        • Felson D.T.
        • et al.
        Factors associated with meniscal extrusion in knees with or at risk for osteoarthritis: The Multicenter Osteoarthritis Study.
        Radiology. 2012; 264: 494-503
        • Acebes C.
        • Romero F.I.
        • Contreras M.A.
        • Mahillo I.
        • Herrero-Beaumont G.
        Dynamic ultrasound assessment of medial meniscal subluxation in knee osteoarthritis.
        Rheumatology. 2013; 52: 1443-1447
        • Achtnich A.
        • Petersen W.
        • Willinger L.
        • et al.
        Medial meniscus extrusion increases with age and BMI and is depending on different loading conditions.
        Knee Surg Sports Traumatol Arthrosc. 2018; 26: 2282-2288