title: Total elbow arthroplasty: Influence of implant positioning on functional outcomes.
abstract: BACKGROUND
  Restoring the axis of rotation is often considered crucial to achieving good functional outcomes of total elbow arthroplasty. The objective of this work was to evaluate whether variations in implant positioning correlated with clinical outcomes.
  
  
  OBJECTIVE
  Clinical outcomes are dictated by the quality of implant positioning.
  
  
  METHODS
  A retrospective review was conducted of data from 25 patients (26 elbows). Function was assessed using a pain score, the Disabilities of the Arm, Shoulder, and Hand (DASH) Score, and the Mayo Elbow Performance Score (MEPS). The patients also underwent a clinical evaluation for measurements of motion range and flexion/extension strength. Position of the humeral and ulnar implants was assessed by computed tomography with reconstruction using OsiriX software. Indices reflecting anterior offset, lateral offset, valgus, height, and rotation were computed by subtracting the ulnar value of each of these variables from the corresponding humeral value. These indices provided a quantitative assessment of whether position errors for the two components had additive effects or, on the contrary, counterbalanced each other. Elbows with prosthetic loosening or extensive epiphyseal destruction were excluded.
  
  
  RESULTS
  Of the 26 elbows, 5 were excluded. In the remaining 21 elbows, the discrepancy between the humeral and ulnar lateral offsets was significantly associated with pain intensity (P ≤ 0.05) and the MEPS (P ≤ 0.05). Anterior position of the ulna relative to the humerus was associated with decreased extension strength (P ≤ 0.05) and worse results for all functional parameters (P ≤ 0.05).
  
  
  CONCLUSIONS
  In the absence of loosening, positioning errors seem to adversely affect functional outcomes, probably by placing inappropriate stress on the soft tissues.
  
  
  METHODS
  III.
authors.affiliation: Hand and Upper Limb Surgical unit, Lapeyronie Teaching Hospital, CHU Lapeyronie, 371, avenue du Doyen-Gaston Giraud, 34295 Montpellier cedex 5, France. Electronic address: hubert.lenoir@laposte.net.
authors.forename: H
authors.initials: H
authors.lastname: Lenoir
authors.affiliation: Research Laboratory: Movement to Health (M2H), EA 2991, STAPS School of Sports Science, Montpellier-1 University, Montpellier, France.
authors.forename: J P
authors.initials: JP
authors.lastname: Micallef
authors.affiliation: Hand and Upper Limb Surgical unit, Lapeyronie Teaching Hospital, CHU Lapeyronie, 371, avenue du Doyen-Gaston Giraud, 34295 Montpellier cedex 5, France.
authors.forename: I
authors.initials: I
authors.lastname: Djerbi
authors.affiliation: Hand and Upper Limb Surgical unit, Lapeyronie Teaching Hospital, CHU Lapeyronie, 371, avenue du Doyen-Gaston Giraud, 34295 Montpellier cedex 5, France.
authors.forename: T
authors.initials: T
authors.lastname: Waitzenegger
authors.affiliation: Hand and Upper Limb Surgical unit, Lapeyronie Teaching Hospital, CHU Lapeyronie, 371, avenue du Doyen-Gaston Giraud, 34295 Montpellier cedex 5, France.
authors.forename: C
authors.initials: C
authors.lastname: Lazerges
authors.affiliation: Hand and Upper Limb Surgical unit, Lapeyronie Teaching Hospital, CHU Lapeyronie, 371, avenue du Doyen-Gaston Giraud, 34295 Montpellier cedex 5, France.
authors.forename: M
authors.initials: M
authors.lastname: Chammas
authors.affiliation: Hand and Upper Limb Surgical unit, Lapeyronie Teaching Hospital, CHU Lapeyronie, 371, avenue du Doyen-Gaston Giraud, 34295 Montpellier cedex 5, France.
authors.forename: B
authors.initials: B
authors.lastname: Coulet
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D057929:Arthroplasty, Replacement, Elbow / Q000379:methods*; D004550:Elbow; D004551:Elbow Joint / Q000503:physiopathology / Q000601:surgery*; D058569:Elbow Prosthesis; D005260:Female; D006801:Humans; D007592:Joint Diseases / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D056888:Patient Positioning; D016059:Range of Motion, Articular; D012189:Retrospective Studies
keywords: Anatomy; Positioning; Rotation axis; Total elbow arthroplasty