title: The role of eccentric and offset humeral head variations in total shoulder arthroplasty.
abstract: BACKGROUND
  Humeral head variations were developed based on anatomic and biomechanical advantages; however, the effect of this expanded prosthetic inventory has yet to be investigated clinically. This study seeks to determine whether prosthetic variety has led to better outcomes, has led to similar outcomes facilitating joint reconstruction, or created any unanticipated complications.
  
  
  METHODS
  One hundred sixty primary total shoulder arthroplasties were performed for osteoarthritis. Patients received 52 standard, 60 eccentric, and 48 offset humeral heads. Head geometry was selected intraoperatively during trialing based on a complementing relationship to the glenoid throughout a near-normal range of motion. Patients had 2 years of follow-up or follow-up until reoperation (mean, 4.7 years; range, 0.8-8.3 years).
  
  
  RESULTS
  Mean pain scores decreased from 4.5 to 1.9 on a 5-point scale (P < .001), mean elevation increased from 94° to 150°, mean external rotation increased from 22° to 57° (P < .001), larger lucent lines (≥ 1.5 mm) or change in glenoid position occurred around 19 components, and survivorship was 98% (95% confidence interval, 97%-100%) at 1 year and 98% (95% confidence interval, 95%-100%) at 5 years. No difference among head configurations was found for any of these outcomes.
  
  
  CONCLUSIONS
  Evolution of designs has provided options to more accurately re-create anatomy including changes caused by osteoarthritis. At the length of follow-up in this study, clinical outcomes, radiographic performance, and survivorship are equivalent when applying these humeral head variations, and no special complications have developed.
authors: Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN 55905, USA.
authors: Adam
authors: A
authors: Sassoon
authors: Bradley
authors: B
authors: Schoch
authors: Peter
authors: P
authors: Rhee
authors: Cathy D
authors: CD
authors: Schleck
authors: William S
authors: WS
authors: Harmsen
authors: John W
authors: JW
authors: Sperling
authors: Robert H
authors: RH
authors: Cofield
mesh_terms: D000368:Aged; D019643:Arthroplasty, Replacement / Q000009:adverse effects / Q000379:methods*; D015331:Cohort Studies; D016001:Confidence Intervals; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D058430:Humeral Head; D007595:Joint Prosthesis; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000000981:diagnostic imaging / Q000601:surgery*; D010147:Pain Measurement; D017060:Patient Satisfaction / Q000706:statistics & numerical data; D018579:Patient Selection; D011474:Prosthesis Design; D011475:Prosthesis Failure; D011859:Radiography; D016059:Range of Motion, Articular / Q000502:physiology*; D020127:Recovery of Function; D012086:Reoperation / Q000379:methods / Q000706:statistics & numerical data; D012189:Retrospective Studies; D018570:Risk Assessment; D012720:Severity of Illness Index; D012785:Shoulder Joint / Q000000981:diagnostic imaging / Q000601:surgery*; D013997:Time Factors; D016896:Treatment Outcome