title: Rate of Improvement in Clinical Outcomes with Anatomic and Reverse Total Shoulder Arthroplasty.
abstract: BACKGROUND
  The rate of clinical improvement has never been studied after anatomic (aTSA) and reverse (rTSA) total shoulder arthroplasty. This study quantifies the rate of improvement after aTSA and rTSA using five different scoring metrics for 1,641 patients.
  
  
  METHODS
  We evaluated 1,641 (69 ± 9.3 years old) patients treated by 14 orthopaedic surgeons using either aTSA or rTSA with a single platform shoulder system. Seven hundred twenty-nine patients received aTSA, and 912 patients received rTSA. Each patient was scored preoperatively and at various follow-up intervals (2 weeks, 6 weeks, 3 months, 6 months, annually, etc.) with a maximum follow-up time of 139 months using the SST, UCLA, ASES, Constant, and SPADI metrics. In addition, range of motion was measured. The rate of improvement was analyzed using a 40-point moving filter treadline over the entire range of follow-up.
  
  
  RESULTS
  All metrics improved in a majority of patients with less than 5% worsening after 6 months. While gains in motion were present in the majority of patients after aTSA, a higher incidence of patients failed to experience improvement in range of motion after rTSA. Clinical worsening was seen in up to 10% and 20% of the visits for active flexion and abduction and external rotation, respectively. The majority of clinical improvement after aTSA and rTSA was noted in the first 6 months with full improvement noted by 12 to 24 months. During the first 12 months, the rate of improvement associated with rTSA patients was generally 30% larger than that of aTSA patients.
  
  
  CONCLUSIONS
  The results of this large-scale database analysis demonstrate the reliability of improvements in outcomes and motion achieved with both aTSA and rTSA for various indications. For both aTSA and rTSA, less than 5% of patients reported worsening in each of the five clinical metrics after 6 months postoperative follow-up time. This study is significant because it quantifies how patient outcomes improve with time following treatment with both aTSA and rTSA. These results can be used to establish realistic patient expectations regarding the typical follow-up time required for pain to be reduced and function restored following surgical treatment with a total shoulder prosthesis.
authors.forename: Ryan
authors.initials: R
authors.lastname: Simovitch
authors.forename: Pierre-Henri
authors.initials: PH
authors.lastname: Flurin
authors.forename: Yann
authors.initials: Y
authors.lastname: Marczuk
authors.forename: Richard
authors.initials: R
authors.lastname: Friedman
authors.forename: Thoma W
authors.initials: TW
authors.lastname: Wrigh
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Zuckerman
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Roche
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019643:Arthroplasty, Replacement / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D001696:Biomechanical Phenomena; D016208:Databases, Factual; D005260:Female; D005602:France; D006801:Humans; D007595:Joint Prosthesis; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000209:etiology; D011446:Prospective Studies; D011474:Prosthesis Design; D016059:Range of Motion, Articular; D020127:Recovery of Function; D012307:Risk Factors; D012785:Shoulder Joint / Q000503:physiopathology / Q000601:surgery*; D013997:Time Factors; D016896:Treatment Outcome; D014481:United States