Study of the Nerve Endings and Mechanoreceptors of the Anterolateral Ligament of the Knee


      To describe the morphology and distribution of the anterolateral ligament of the knee (ALL) nerve endings, aiming to understand the interaction between the proprioceptive system and knee mechanics.


      Twenty ALLs were obtained from fresh frozen cadavers. The ligaments were measured, weighed, and cut. Sections (10 μm) were prepared in hematoxylin and eosin–stained slides to analyze tissue integrity, and 50-μm sections were subjected to immunofluorescence with the protein gene product 9.5 as primary antibody and Alexa Fluor 488 as secondary antibody, followed by microscopic analysis.


      The ALL was identified in 100% of the dissections, exhibiting a mean (± standard deviation) length of 4.0 ± 0.4 cm, a mean width of 5.5 ± 0.8 mm, and a mean weight of 0.9 ± 0.2 g. The histological sections in hematoxylin and eosin showed dense, well-organized collagen and the presence of vascular tissue. All the specimens analyzed contained type I (Ruffini-like) mechanoreceptors and free nerve endings (type IV), varying from parallel to intertwined fibers. Unclassified nerve endings with different irregular shapes were also found. The neural elements occupied 0.6% ± 0.3% of the ligament area, and most were observed near the origin of ALL insertions.


      The ALL exhibits a peripheral nerve structure, primarily type I and IV mechanoreceptors. These findings suggest that the ALL is important for the proprioception and anterolateral stabilization of the knee.

      Clinical Relevance

      It is important to understand ALL innervation and infer how an injury could compromise the proprioceptive role of the lateral compartment, as the ligaments contribute dynamically to stability through proprioceptive control of muscle forces. The findings confirm that the ALL is highly innervated by mechanoreceptors and may have a proprioceptive role in conjunction with the lateral collateral ligament in the lateral region of the knee.
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        • Vincent J.P.
        • Magnussen R.A.
        • Gezmez F.
        • et al.
        The anterolateral ligament of the human knee: An anatomic and histologic study.
        Knee Surg Sport Traumatol Arthrosc. 2012; 20: 147-152
        • Claes S.
        • Vereecke E.
        • Maes M.
        • Victor J.
        • Verdonk P.
        • Bellemans J.
        Anatomy of the anterolateral ligament of the knee.
        J Anat. 2013; 223: 321-328
        • Helito C.P.
        • Demange M.K.
        • Bonadio M.B.
        • et al.
        Anatomy and histology of the knee anterolateral ligament.
        Orthop J Sport Med. 2013; 1 (2325967113513546)
        • Van Der Watt L.
        • Khan M.
        • Rothrauff B.B.
        • et al.
        The structure and function of the anterolateral ligament of the knee: A systematic review.
        Arthroscopy. 2015; 31: 569-582.e3
        • Pomajzl R.
        • Maerz T.
        • Shams C.
        • Guettler J.
        • Bicos J.
        A review of the anterolateral ligament of the knee: Current knowledge regarding its incidence, anatomy, biomechanics, and surgical dissection.
        Arthroscopy. 2015; 31: 583-591
        • de Lima D.A.
        • Helito C.P.
        • de Lima L.L.
        • de Castro Silva D.
        • Cavalcante M.L.C.
        • Leite J.A.D.
        Anatomy of the anterolateral ligament of the knee: A systematic review.
        Arthroscopy. 2019; 35: 670-681
        • Claes S.
        • Luyckx T.
        • Vereecke E.
        • Bellemans J.
        The Segond fracture: A bony injury of the anterolateral ligament of the knee.
        Arthroscopy. 2014; 30: 1475-1482
        • Helito C.P.
        • Camargo D.B.
        • Sobrado M.F.
        • et al.
        Combined reconstruction of the anterolateral ligament in chronic ACL injuries leads to better clinical outcomes than isolated ACL reconstruction.
        Knee Surg Sport Traumatol Arthrosc. 2018; : 1-8
        • Sonnery-Cottet B.
        • Thaunat M.
        • Freychet B.
        • Pupim B.H.B.
        • Murphy C.G.
        • Claes S.
        Outcome of a combined anterior cruciate ligament and anterolateral ligament reconstruction technique with a minimum 2-year follow-up.
        Am J Sports Med. 2015; 43: 1598-1605
        • Ariel de Lima D.
        • Helito C.P.
        • Lima F.R.A.D.
        • Leite J.A.D.
        Surgical indications for anterior cruciate ligament reconstruction combined with extra-articular lateral tenodesis or anterolateral ligament reconstruction.
        Rev Bras Ortop. 2018; 53: 661-667
        • Imbert P.
        • Lutz C.
        • Daggett M.
        • et al.
        Isometric characteristics of the anterolateral ligament of the knee: A cadaveric navigation study.
        Arthroscopy. 2016; 32: 2017-2024
        • Sonnery-Cottet B.
        • Lutz C.
        • Daggett M.
        • et al.
        The involvement of the anterolateral ligament in rotational control of the knee.
        Am J Sports Med. 2015; 44: 1209-1214
        • Helito C.P.
        • Bonadio M.B.
        • Soares T.Q.
        • et al.
        The meniscal insertion of the knee anterolateral ligament.
        Surg Radiol Anat. 2016; 38: 223-228
        • Helito C.P.
        • do Prado Torres J.A.
        • Bonadio M.B.
        • et al.
        Anterolateral ligament of the fetal knee: An anatomic and histological study.
        Am J Sports Med. 2017; 45: 91-96
        • Macchi V.
        • Porzionato A.
        • Morra A.
        • et al.
        The anterolateral ligament of the knee: A radiologic and histotopographic study.
        Surg Radiol Anat. 2016; 38: 341-348
        • Caterine S.
        • Litchfield R.
        • Johnson M.
        • Chronik B.
        • Getgood A.
        A cadaveric study of the anterolateral ligament: Re-introducing the lateral capsular ligament.
        Knee Surg Sport Traumatol Arthrosc. 2015; 23: 3186-3195
        • Schultz R.A.
        • Miller D.C.
        • Kerr C.S.
        • Micheli L.
        Mechanoreceptors in human cruciate ligaments: A histological study.
        J Bone Joint Surg Am. 1984; 66: 1072-1076
        • Schutte M.J.
        • Dabezies E.J.
        • Zimny M.L.
        • Happel L.T.
        Neural anatomy of the human anterior cruciate ligament.
        J Bone Joint Surg Am. 1987; 69: 243-247
        • Zimny M.L.
        • Schutte M.
        • Dabezies E.
        Mechanoreceptors in the human anterior cruciate ligament.
        Anat Rec. 1986; 214: 204-209
        • Del Valle M.E.
        • Harwin S.F.
        • Maestro A.
        • Murcia A.
        • Vega J.A.
        Immunohistochemical analysis of mechanoreceptors in the human posterior cruciate ligament: A demonstration of its proprioceptive role and clinical relevance.
        J Arthroplasty. 1998; 13: 916-922
        • Katonis P.G.
        • Assimakopoulos A.P.
        • Agapitos M.V.
        • Exarchou E.I.
        Mechanoreceptors in the posterior cruciate ligament: Histologic study on cadaver knees.
        Acta Orthop. 1991; 62: 276-278
        • Franchi A.
        • Zaccherotti G.
        • Aglietti P.
        Neural system of the human posterior cruciate ligament in osteoarthritis.
        J Arthroplasty. 1995; 10: 679-682
        • Yan J.
        • Sasaki W.
        • Hitomi J.
        Anatomical study of the lateral collateral ligament and its circumference structures in the human knee joint.
        Surg Radiol Anat. 2010; 32: 99-106
        • Çabuk H.
        • Kuşku Çabuk F.
        Mechanoreceptors of the ligaments and tendons around the knee.
        Clin Anat. 2016; 29: 789-795
        • Daggett M.
        • Busch K.
        • Sonnery-Cottet B.
        Surgical dissection of the anterolateral ligament.
        Arthrosc Tech. 2016; 5: e185-e188
        • Jew J.Y.
        • Berger E.J.
        • Berger R.A.
        • Lin Y.T.
        Fluorescence immunohistochemistry and confocal scanning laser microscopy: A protocol for studies of joint innervation.
        Acta Orthop Scand. 2003; 74: 689-696
        • Freeman M.
        • Wyke B.
        The innervation of the knee joint. An anatomical and histological study in the cat.
        J Anat. 1967; 101: 505-532
        • Freeman M.A.R.
        • Wyke B.
        The innervation of the ankle joint. An anatomical and histological study in the cat.
        Cells Tissues Organs. 1967; 68: 321-333
        • Backenkohler U.
        • Strasmann T.J.
        • Halata Z.
        Topography of mechanoreceptors in the shoulder joint region—A computer-aided 3D reconstruction in the laboratory mouse.
        Anat Rec. 1997; 248: 433-441
        • McLain R.F.
        • Pickar J.G.
        Mechanoreceptor endings in human thoracic and lumbar facet joints.
        Spine. 1998; 23: 168-173
        • Raunest J.
        • Sager M.
        • Bürgener E.
        Proprioception of the cruciate ligaments: Receptor mapping in an animal model.
        Arch Orthop Trauma Surg. 1998; 118: 159-163
        • Amir G.
        • Lowe J.
        • Finsterbush A.
        Histomorphometric analysis of innervation of the anterior cruciate ligament in osteoarthritis.
        J Orthop Res. 1995; 13: 78-82
        • Assimakopoulos A.P.
        • Katonis P.G.
        • Agapitos M.V.
        • Exarchou E.I.
        The innervation of the human meniscus.
        Clin Orthop Relat Res. 1992; : 232-236
        • Dimitroulias A.
        • Tsonidis C.
        • Natsis K.
        • et al.
        An immunohistochemical study of mechanoreceptors in lumbar spine intervertebral discs.
        J Clin Neurosci. 2010; 17: 742-745
        • Hagert E.
        • Garcia-Elias M.
        • Forsgren S.
        • Ljung B.O.
        Immunohistochemical analysis of wrist ligament innervation in relation to their structural composition.
        J Hand Surg Am. 2007; 32: 30-36
        • Mihalko W.M.
        • Creek A.T.
        • Mary M.N.
        • Williams J.L.
        • Komatsu D.E.
        Mechanoreceptors found in a posterior cruciate ligament from a well-functioning total knee arthroplasty retrieval.
        J Arthroplasty. 2011; 26 (504.e9-504.e12)
        • Vilensky J.A.
        • O’Connor B.L.
        • Fortin J.D.
        • et al.
        Histologic analysis of neural elements in the human sacroiliac joint.
        Spine. 2002; 27: 1202-1207
        • Jang Y.C.
        • Isik F.F.
        • Gibran N.S.
        Nerve distribution in hemangiomas depends on the proliferative state of the microvasculature.
        J Surg Res. 2000; 93: 144-148
        • Jew J.Y.
        • Fink C.A.
        • Williams T.H.
        Tyrosine hydroxylase- and nitric oxide synthase-immunoreactive nerve fibers in mitral valve of young adult and aged Fischer 344 rats.
        J Auton Nerv Syst. 1996; 58: 35-43
        • Shirai C.
        • Ohtori S.
        • Kishida S.
        • Harada Y.
        • Moriya H.
        The pattern of distribution of PGP 9.5 and TNF-alpha immunoreactive sensory nerve fibers in the labrum and synovium of the human hip joint.
        Neurosci Lett. 2009; 450: 18-22
        • Hirasawa Y.
        • Okajima S.
        • Ohta M.
        • Tokioka T.
        Nerve distribution to the human knee joint: Anatomical and immunohistochemical study.
        Int Orthop. 2000; 24: 1-4
        • Daggett M.
        • Helito C.
        • Cullen M.
        • et al.
        The anterolateral ligament: An anatomic study on sex-based differences.
        Orthop J Sport Med. 2017; 5
        • Toro-Ibarguen A.N.
        • Pretell-Mazzini J.
        • Pérez E.
        • Pedrajas I.
        • Cano-Egea J.M.
        • Ramón Sanudo J.
        The anterolateral ligament: A cadaveric study in fetuses.
        Clin Anat. 2017; 30: 625-634
        • Corbo G.
        • Norris M.
        • Getgood A.
        • Burkhart T.A.
        The infra-meniscal fibers of the anterolateral ligament are stronger and stiffer than the supra-meniscal fibers despite similar histological characteristics.
        Knee Surg Sport Traumatol Arthrosc. 2017; 25: 1078-1085
        • Helito C.P.
        • Helito P.V.P.
        • Bonadio M.B.
        • et al.
        Correlation of magnetic resonance imaging with knee anterolateral ligament anatomy: A cadaveric study.
        Orthop J Sport Med. 2015; 3 (2325967115621024)
        • Kennedy M.I.
        • Claes S.
        • Fuso F.A.F.
        • et al.
        The anterolateral ligament: An anatomic, radiographic, and biomechanical analysis.
        Am J Sports Med. 2015; 43: 1606-1615
        • Zens M.
        • Niemeyer P.
        • Ruhhammer J.
        • et al.
        Length changes of the anterolateral ligament during passive knee motion: A human cadaveric study.
        Am J Sports Med. 2015; (0363546515594373)
        • Helito C.P.
        • De Souza Miyahara H.
        • Bonadio M.B.
        • et al.
        Anatomical study on the anterolateral ligament of the knee.
        Rev Bras Ortop. 2013; 48: 368-373
        • Fardin P.B.A.
        • Lizardo JH. de F.
        • Baptista J. da S.
        Study of the anterolateral ligament of the knee in formalin-embedded cadavers.
        Acta Ortop Bras. 2017; 25: 89-92
        • Sabzevari S.
        • Rahnemai-Azar A.A.
        • Albers M.
        • Linde M.
        • Smolinski P.
        • Fu F.H.
        Anatomic and histological investigation of the anterolateral capsular complex in the fetal knee.
        Am J Sports Med. 2017; 45: 1383-1387
        • Helito C.P.
        • do Amaral C.
        • Nakamichi Y.D.
        • et al.
        Why do authors differ with regard to the femoral and meniscal anatomic parameters of the knee anterolateral ligament? Dissection by layers and a description of its superficial and deep layers.
        Orthop J Sport Med. 2016; 4 (2325967116675604)
        • Stijak L.
        • Bumbaširević M.
        • Radonjić V.
        • et al.
        Anatomic description of the anterolateral ligament of the knee.
        Knee Surg Sport Traumatol Arthrosc. 2016; 24: 2083-2088
        • Kosy J.D.
        • Soni A.
        • Venkatesh R.
        • Mandalia V.I.
        The anterolateral ligament of the knee: Unwrapping the enigma. Anatomical study and comparison to previous reports.
        J Orthop Traumatol. 2016; 17: 303-308
        • Roessler P.P.
        • Schüttler K.F.
        • Stein T.
        • et al.
        Anatomic dissection of the anterolateral ligament (ALL) in paired fresh-frozen cadaveric knee joints.
        Arch Orthop Trauma Surg. 2017; 137: 249-255
        • Shea K.G.
        • Milewski M.D.
        • Cannamela P.C.
        • et al.
        Anterolateral ligament of the knee shows variable anatomy in pediatric specimens.
        Clin Orthop Relat Res. 2017; 475: 1583-1591
        • Sonia Farhan P.H.
        • Sudhakaran R.
        • Thilak J.
        Solving the mystery of the antero lateral ligament.
        J Clin Diagnostic Res. 2017; 11: AC01-AC04
        • Neri T.
        • Palpacuer F.
        • Testa R.
        • et al.
        The anterolateral ligament: Anatomic implications for its reconstruction.
        Knee. 2017; 24: 1083-1089
        • Daggett M.
        • Ockuly A.C.
        • Cullen M.
        • et al.
        Femoral origin of the anterolateral ligament: an anatomic analysis.
        Arthroscopy. 2016; 32: 835-841
        • Johansson H.
        • Sjölander P.
        • Sojka P.
        A sensory role for the cruciate ligaments.
        Clin Orthop Relat Res. 1991; 268: 161-178
        • de Avila G.
        • O’Connor B.L.
        • Visco D.M.
        • Sisk T.D.
        The mechanoreceptor innervation of the human fibular collateral ligament.
        J Anat. 1989; 162: 1-7
        • Mine T.
        • Kimura M.
        • Sakka A.
        • Kawai S.
        Innervation of nociceptors in the menisci of the knee joint: An immunohistochemical study.
        Arch Orthop Trauma Surg. 2000; 120: 201-204
        • Grigg P.
        • Schaible H.G.
        • Schmidt R.F.
        Mechanical sensitivity of group III and IV afferents from posterior articular nerve in normal and inflamed cat knee.
        J Neurophysiol. 1986; 55: 635-643
        • Halata Z.
        • Rettig T.
        • Schulze W.
        The ultrastructure of sensory nerve endings in the human knee joint capsule.
        Anat Embryol (Berl). 1985; 172: 265-275
        • Solomonow M.
        Sensory-motor control of ligaments and associated neuromuscular disorders.
        J Electromyogr Kinesiol. 2006; 16: 549-567
        • Amiri S.
        • Cooke D.
        • Kim I.Y.
        • Wyss U.
        Mechanics of the passive knee joint. Part 1: The role of the tibial articular surfaces in guiding the passive motion.
        Proc Inst Mech Eng Part H J Eng Med. 2006; 220: 813-822
        • Amiri S.
        • Cooke D.
        • Kim I.Y.
        • Wyss U.
        Mechanics of the passive knee joint. Part 2: Interaction between the ligaments and the articular surfaces in guiding the joint motion.
        Proc Inst Mech Eng H. 2007; 221: 821-832
        • Rein S.
        • Semisch M.
        • Garcia-Elias M.
        • Lluch A.
        • Zwipp H.
        • Hagert E.
        Immunohistochemical mapping of sensory nerve endings in the human triangular fibrocartilage complex.
        Clin Orthop Relat Res. 2015; 473: 3245-3253

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