title: Similar histopathological picture in males with Achilles and patellar tendinopathy.
abstract: OBJECTIVE
  To ascertain whether there are differences in the histopathological appearance of tendinopathic Achilles and patellar tendons.
  
  
  METHODS
  In males, we studied biopsies from tendinopathic Achilles (N = 28; average age 34.1 yr) and patellar tendons (N = 28; average age 32.1), Achilles tendons (N = 21; average age 61.8 yr) from deceased patients with no known tendon pathology, and patellar tendons (N = 15; average age 28.3) from patients undergoing anterior cruciate ligament reconstruction. Hematoxylineosin stained slides were interpreted using a semiquantitative grading scale (0: normal to 3: maximally abnormal) for fiber structure, fiber arrangement, rounding of the nuclei, regional variations in cellularity, increased vascularity, decreased collagen stainability, and hyalinization. All slides were assessed blindly twice, the agreement between two readings ranging from 0.170 to 0.750 (kappa statistics).
  
  
  RESULTS
  The highest mean score of tendinopathic Achilles tendons was not significantly different from that of tendinopathic patellar tendons (11.6 +/- 5 and 10.4 +/- 3, respectively). The ability to differentiate between an Achilles tendon and a patellar tendon was low.
  
  
  CONCLUSIONS
  Tendinopathic Achilles and patellar tendons show a similar histological picture. It was not possible to identify whether a specimen had been harvested from an Achilles or a patellar tendon on the basis of histological examination. The general pattern of degeneration was common to both tendinopathic Achilles and patellar tendons. A common, as yet unidentified, etiopathological mechanism may have acted on both these tendon populations.
authors.affiliation: Department of Trauma and Orthopaedic Surgery, Keele University School of Medicine, Stoke on Trent, Keele, United Kingdom. n.maffulli@keele.ac.uk
authors.forename: Nicola
authors.initials: N
authors.lastname: Maffulli
authors.forename: Vittorino
authors.initials: V
authors.lastname: Testa
authors.forename: Giovanni
authors.initials: G
authors.lastname: Capasso
authors.forename: Stanley W
authors.initials: SW
authors.lastname: Ewen
authors.forename: Alessio
authors.initials: A
authors.lastname: Sullo
authors.forename: Francesco
authors.initials: F
authors.lastname: Benazzo
authors.forename: John B
authors.initials: JB
authors.lastname: King
mesh_terms: D000125:Achilles Tendon / Q000473:pathology*; D000293:Adolescent; D000328:Adult; D006801:Humans; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010329:Patella / Q000473:pathology*; D015203:Reproducibility of Results; D013708:Tendon Injuries / Q000473:pathology*; D013710:Tendons / Q000473:pathology*