title: Comparative analysis of the morphologic structure of quadriceps and patellar tendon: a descriptive laboratory study.
abstract: OBJECTIVE
  The difference in ultimate strength between the quadriceps and patellar tendon could be reflected by different morphologic features.
  
  
  METHODS
  Standardized samples of quadriceps and patellar tendons were harvested from 20 cadavers and were investigated via light and electron microscopy, immunohistochemistry, and morphometry. The thickness of collagen fibrils, fibril-interstitium ratio, density of blood vessels, density of fibroblasts, and distribution of collagen fibrils were analyzed.
  
  
  RESULTS
  In comparison with the patellar tendon, the quadriceps tendon showed a significantly higher fibril-interstitium ratio (P = .0004) and a higher fibroblast density (P = .0011). No differences regarding the thickness of collagen fibrils, density of blood vessels, and distribution of fibrils were found.
  
  
  CONCLUSIONS
  The quadriceps tendon graft can provide approximately 20% more collagen than the patellar tendon graft with the same thickness. This fact can play an important role in the better ultimate strength of the quadriceps tendon.
  
  
  CONCLUSIONS
  The detailed anatomic description of the quadriceps tendon and patellar tendon explains the difference in their ultimate strength.
authors.affiliation: Department of Pathology, University of Heidelberg, Germany. phadjicostas@yahoo.com
authors.forename: Panayiotis T
authors.initials: PT
authors.lastname: Hadjicostas
authors.forename: Panayotis N
authors.initials: PN
authors.lastname: Soucacos
authors.forename: Irina
authors.initials: I
authors.lastname: Berger
authors.forename: Nadezda
authors.initials: N
authors.lastname: Koleganova
authors.forename: Hans H
authors.initials: HH
authors.lastname: Paessler
mesh_terms: D000328:Adult; D000368:Aged; D002102:Cadaver; D003094:Collagen / Q000648:ultrastructure; D005260:Female; D005347:Fibroblasts / Q000648:ultrastructure; D006801:Humans; D007717:Knee / Q000033:anatomy & histology*; D008297:Male; D008875:Middle Aged; D017847:Patellar Ligament / Q000033:anatomy & histology; D052097:Quadriceps Muscle; D013710:Tendons / Q000033:anatomy & histology*
chemical_list: D003094:Collagen