title: Glenoid subchondral bone density distribution in male total shoulder arthroplasty subjects with eccentric and concentric wear.
abstract: BACKGROUND
  Glenoid component loosening in total shoulder arthroplasty may be prevented by component placement on a congruent and adequate bony surface. Glenoid subchondral bone density (SBD) variability may be correlated with this concept. This study analyzed the 3-dimensional distribution of glenoid SBD in total shoulder arthroplasty patients with osteoarthritis.
  
  
  METHODS
  Three-dimensional computed tomography osteoabsorptiometry (CT-OAM) was performed in 42 men (21 with eccentric and 21 with concentric wear patterns) with glenohumeral arthritis. Glenoid SBD was measured from the joint surface based on 5 clinically relevant topographic zones. The correlation of the wear pattern with the SBD distribution was investigated.
  
  
  RESULTS
  The glenoid subarticular layers could be separated into distinct regions: calcified cartilage (≤ 1.5 mm), subchondral plate (2-4.5 mm) and cancellous bone (≥ 5 mm). There were significant differences in SBD among these layers within and between patients with concentric and eccentric wear patterns. In concentric glenoids, the SBD distribution was homogeneous, with greater mineralization in the central zone, 1,749.1 ± 162.3 Hounsfield units (HU) (at 2.5 mm), compared with the posterior, anterior, and superior zones (P < .001). In the eccentric group, the SBD distribution was inhomogeneous. Mineralization was greatest in the posterior zone, 1,739.0 ± 172.6 HU (at 2.5 mm), followed by the inferior zone, 1,722.1 ± 186.6 HU (at 3 mm).
  
  
  CONCLUSIONS
  This study represents the first study using CT-OAM to evaluate the 3-dimensional SBD distribution of the glenoid vault for different arthritic wear patterns. The study findings indicate that the SBD distribution is dependent on (1) depth from the articular surface, (2) topographic zone, and (3) wear pattern. CT-OAM may be an effective tool to assist in preoperative planning for shoulder arthroplasty.
authors.affiliation: Phillip Spiegel Orthopaedic Research Laboratory, Foundation for Orthopaedic Research and Education, Tampa, FL, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Simon
authors.affiliation: Department of Shoulder and Elbow Surgery, Florida Orthopaedic Institute, Tampa, FL, USA.
authors.forename: Anil
authors.initials: A
authors.lastname: Gupta
authors.affiliation: Department of Shoulder and Elbow Surgery, Florida Orthopaedic Institute, Tampa, FL, USA.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Pappou
authors.affiliation: Department of Shoulder and Elbow Surgery, Florida Orthopaedic Institute, Tampa, FL, USA.
authors.forename: Michael M
authors.initials: MM
authors.lastname: Hussey
authors.affiliation: Phillip Spiegel Orthopaedic Research Laboratory, Foundation for Orthopaedic Research and Education, Tampa, FL, USA.
authors.forename: Brandon G
authors.initials: BG
authors.lastname: Santoni
authors.affiliation: Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL, USA.
authors.forename: Nozomu
authors.initials: N
authors.lastname: Inoue
authors.affiliation: Department of Shoulder and Elbow Surgery, Florida Orthopaedic Institute, Tampa, FL, USA. Electronic address: mfrankle@floridaortho.com.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Frankle
mesh_terms: D000368:Aged; D019643:Arthroplasty, Replacement / Q000009:adverse effects; D015519:Bone Density; D019544:Equipment Failure Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery; D011475:Prosthesis Failure; D012540:Scapula / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery; D012785:Shoulder Joint / Q000000981:diagnostic imaging / Q000601:surgery*; D014057:Tomography, X-Ray Computed
keywords: Shoulder; glenoid; glenoid wear patterns; loosening; osteoabsorptiometry; osteoarthritis; total shoulder arthroplasty