title: Assessment of bone quality within the tuberosities of the osteoporotic humeral head: relevance for anchor positioning in rotator cuff repair.
abstract: BACKGROUND
  Tears of the rotator cuff are highly prevalent in patients older than 60 years, thereby presenting a population also suffering from osteopenia or osteoporosis. Suture fixation in the bone depends on the holding strength of the anchoring technique, whether a bone tunnel or suture anchor is selected. Because of osteopenic or osteoporotic bone changes, suture anchors in the older patient might pull out, resulting in failure of repair.
  
  
  OBJECTIVE
  The aim of our study was to analyze the bone quality within the tuberosities of the osteoporotic humeral head using high-resolution quantitative computed tomography (HR-pQCT).
  
  
  METHODS
  Descriptive laboratory study.
  
  
  METHODS
  Thirty-six human cadaveric shoulders were analyzed using HR-pQCT. The mean bone volume to total volume (BV/TV) as well as trabecular bone mineral densities (trabBMDs) of the greater tuberosity (GT) and the lesser tuberosity (LT) were determined. Within the GT, 6 volumes of interest (VOIs) within the LT, and 2 VOIs and 1 control volume within the subchondral area beyond the articular surface were set.
  
  
  RESULTS
  Comparing BV/TV of the medial and the lateral row, significantly higher values were found medially (P < .001). The highest BV/TV, 0.030% + or - 0.027%, was found in the posteromedial portion of the GT (P < .05). Regarding the analysis of the LT, no difference was found comparing the superior (BV/TV: 0.024% + or - 0.022%) and the inferior (BV/TV: 0.019% + or - 0.016%) portion. Analyzing trabBMD, equal proportions were found. An inverse correlation with a correlation coefficient of -0.68 was found regarding BV/TV of the posterior portion of the GT and age (P < .05).
  
  
  CONCLUSIONS
  Significant regional differences of trabecular microarchitecture were found in our HR-pQCT study. The volume of highest bone quality resulted for the posteromedial aspect of the GT. Moreover, a significant correlation of bone quality within the GT and age was found, while the bone quality within the LT seems to be independent from it.
  
  
  CONCLUSIONS
  The shape of the rotator cuff tear largely determines the bony site of tendon reattachment, although the surgeon has distinct options to modify anchor positioning. According to our results, placement of suture anchors in a medialized way at the border to the articular surface might guarantee a better structural bone stock.
authors.affiliation: Department of Orthopedic Sports Surgery, Klinikum Rechts der Isar, Technische Universitaet Muenchen, Ismaningerstrasse 22, D-81675 Munich, Germany. Kirchhoff@lrz.tu-muenchen.de
authors.forename: Chlodwig
authors.initials: C
authors.lastname: Kirchhoff
authors.forename: Volker
authors.initials: V
authors.lastname: Braunstein
authors.forename: Stefan
authors.initials: S
authors.lastname: Milz
authors.forename: Christoph M
authors.initials: CM
authors.lastname: Sprecher
authors.forename: Florian
authors.initials: F
authors.lastname: Fischer
authors.forename: Andrea
authors.initials: A
authors.lastname: Tami
authors.forename: Philipp
authors.initials: P
authors.lastname: Ahrens
authors.forename: Andreas B
authors.initials: AB
authors.lastname: Imhoff
authors.forename: Stefan
authors.initials: S
authors.lastname: Hinterwimmer
mesh_terms: D015502:Absorptiometry, Photon; D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density; D002102:Cadaver; D005260:Female; D006801:Humans; D006811:Humerus / Q000000981:diagnostic imaging* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000000981:diagnostic imaging* / Q000601:surgery; D016059:Range of Motion, Articular; D000070636:Rotator Cuff Injuries; D053441:Suture Anchors