title: Risk of insufficient internal rotation after bilateral reverse shoulder arthroplasty: clinical and patient-reported outcome in 57 patients.
abstract: BACKGROUND
  Bilateral reverse shoulder arthroplasty (RSA) is controversial because of potential rotational deficits impairing daily living activities. We assessed achievement of insufficient internal rotation (IR) and associated factors in bilateral RSA patients.
  
  
  METHODS
  Fifty-seven staged bilateral RSA patients with a minimum of 1 year of follow-up after the second intervention were identified from our local monocentric register. Shoulder range of motion (including IR using the Apley scratch test), strength, and Constant and Shoulder Pain and Disability Index scores were assessed preoperatively and 6, 12, and 24 months postoperatively.
  
  
  RESULTS
  Before surgery, both shoulders were similar regarding imaging parameters, but first operated shoulders tended to have poorer function. One year after the first RSA, 21% of patients had insufficient IR (not reaching the lumbosacral junction) compared with 33% after the second intervention (P = .180). At 2 years, 5% of patients had insufficient IR on both sides. Patients with insufficient IR on the second side at baseline (relative risk [RR], 1.8 [1.0-3.2]) and patients with insufficient IR 1 year after the first RSA (RR, 3.0 [1.6-5.6]) were more likely to have insufficient IR 1 year after the second RSA. Constant and Shoulder Pain and Disability Index scores and abduction of the second side were significantly worse 1 year after the second RSA (P ≤ .047); at 2 years, there were no differences in functional outcome between shoulders.
  
  
  CONCLUSIONS
  A minority of bilateral RSA patients did not achieve sufficient IR on at least 1 side. Staged surgery is justified, particularly when the outcome of the initial operation is satisfactory.
authors.affiliation: Upper Extremities Department, Schulthess Clinic, Zürich, Switzerland.
authors.forename: Barbara
authors.initials: B
authors.lastname: Wirth
authors.affiliation: Upper Extremities Department, Schulthess Clinic, Zürich, Switzerland; Research and Development Department, Schulthess Clinic, Zürich, Switzerland.
authors.forename: Christoph
authors.initials: C
authors.lastname: Kolling
authors.affiliation: Upper Extremities Department, Schulthess Clinic, Zürich, Switzerland.
authors.forename: Hans-Kaspar
authors.initials: HK
authors.lastname: Schwyzer
authors.affiliation: Upper Extremities Department, Schulthess Clinic, Zürich, Switzerland.
authors.forename: Matthias
authors.initials: M
authors.lastname: Flury
authors.affiliation: Upper Extremities Department, Schulthess Clinic, Zürich, Switzerland; Research and Development Department, Schulthess Clinic, Zürich, Switzerland. Electronic address: laurent.audige@kws.ch.
authors.forename: Laurent
authors.initials: L
authors.lastname: Audigé
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000072228:Arthroplasty, Replacement, Shoulder / Q000009:adverse effects / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D000071066:Patient Reported Outcome Measures; D016059:Range of Motion, Articular; D012307:Risk Factors; D012399:Rotation; D012785:Shoulder Joint / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery; D020069:Shoulder Pain / Q000209:etiology; D013997:Time Factors; D016896:Treatment Outcome
keywords: Bilateral reverse shoulder arthroplasty; Case Series; Constant score; Level IV; Treatment Study; case series; complications; internal rotation; patient-reported outcomes