title: Histological features of the ACL remnant in partial tears.
abstract: BACKGROUND
  The aim of this study was to investigate the histological features of the remaining fibers bridging the femur and tibia in partial ACL tears.
  
  
  METHODS
  Twenty-six ACL remnants were harvested from patients who had arthroscopic criteria concordant with a partial tear. Histological analysis includes cellularity, blood vessel density evaluation and characterization of the femoral bony insertion morphology. Immunohistochemical studies were carried out to determine cells positive for α-smooth actin and for mechanoreceptor detection.
  
  
  RESULTS
  In these samples, a normal femoral insertion of the remnant was present in 22.7% of the cases. In 54% of the samples, substantial areas of hypercellularity were observed. Myofibroblasts were the predominant cell type and numerous cells positive for α-smooth actin were detected at immunostaining. Blood vessel density was increased in hypercellularity areas and in the synovial sheet. Free nerve endings and few Golgi or Ruffini corpuscles were detected in 41% of the specimens. The cellularity was correlated to the time between injury to surgery (p=0.001).
  
  
  CONCLUSIONS
  Competent histological structures including a well-vascularized synovial sheet, numerous fibroblasts and myofibroblasts and mechanoreceptors were found in ACL remnants. These histological findings bring additional knowledge towards the preservation of the ACL remnant in partial tears when ACL reconstruction or augmentation is considered.
  
  
  CONCLUSIONS
  Descriptive laboratory study.
authors.affiliation: Centre Orthopédique Santy, Hôpital Privé Jean Mermoz, Lyon, France.
authors.forename: Bertrand
authors.initials: B
authors.lastname: Sonnery-Cottet
authors.affiliation: CHU de Caen, Caen cedex 14003, France.
authors.forename: Céline
authors.initials: C
authors.lastname: Bazille
authors.affiliation: CHU de Caen, Caen cedex 14003, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Hulet
authors.affiliation: Clinique du Sport, 9 rue Jean Moulin, Mérignac 33700, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Colombet
authors.affiliation: Centre Borely Mermoz, 118 rue Jean Mermoz, Marseille 13008, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Cucurulo
authors.affiliation: Clinique des Cèdres, 48 av Grugliasco, Echirolles 38130, France.
authors.forename: Jean Claude
authors.initials: JC
authors.lastname: Panisset
authors.affiliation: Médipole Garonne, 45 rue de Gironis, Toulouse 31100, France.
authors.forename: Jean François
authors.initials: JF
authors.lastname: Potel
authors.affiliation: CHU de la Croix Rousse, 103 Grande Rue de la Croix-Rousse, Lyon 69004, France.
authors.forename: Elvire
authors.initials: E
authors.lastname: Servien
authors.affiliation: Service de Chirurgie Orthopédique, Hôpital de l'Archet 2, 151 route St A. de Ginestière, Nice 06200, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Trojani
authors.affiliation: IAL Nollet, 23 rue Brochant, Paris 75017, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: Djian
authors.affiliation: CMC Paris 5, 36, Boulevard Saint-Marcel, Paris 5 75005, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Graveleau
authors.affiliation: Hôpital André Mignot, 177 rue de Versailles, Le Chesnay 78150, France. Electronic address: npujol@ch-versailles.fr.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Pujol
mesh_terms: D000293:Adolescent; D000328:Adult; D016118:Anterior Cruciate Ligament / Q000473:pathology; D000070598:Anterior Cruciate Ligament Injuries; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D001182:Arthroscopy; D005260:Female; D005269:Femur / Q000473:pathology* / Q000601:surgery; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013977:Tibia / Q000473:pathology* / Q000601:surgery; D014945:Wound Healing / Q000502:physiology*; D055815:Young Adult
keywords: ACL biology; ACL histology; Anterior cruciate ligament; Graft healing; Partial ACL tears