title: Development of a Prediction Model to Estimate the Risk of Walking Limitations in Patients with Total Knee Arthroplasty.
abstract: OBJECTIVE
  Early and accurate risk prediction of walking limitations after total knee arthroplasty (TKA) is important for clinical and economic reasons. However, to our knowledge, no studies have systematically integrated multiple predictors into a single, clinically practical model. Our study aimed to develop a prediction model to estimate the risk of post-TKA walking limitations.
  
  
  METHODS
  We performed a prospective cohort study of 1096 patients who underwent elective, primary TKA between July 2013 and September 2014. Candidate predictors included patient demographics, surgical factors, and pre- and early (1-mo) post-TKA functional measures. The outcome of interest was self-reported walking limitations at 6 months of post-TKA. We used multivariable proportional odds regression with bootstrap internal validation to develop the model.
  
  
  RESULTS
  In all, 12% of patients reported walking limitations (maximum walk time ≤ 15 min) at 6 months postsurgery. The main predictors of increasing levels of walking limitations were preoperative walking limitations (overall p < 0.001), higher levels of body mass index [interquartile range (IQR)-OR 1.3, 95% CI 1.2-1.5], lower values of 1-month post-TKA gait speed (IQR-OR 1.9, 95% CI 1.3-2.6), the presence of contralateral knee pain (OR 1.9, 95% CI 1.2-3.0), and the use of a quadstick preoperatively (OR 3.5, 95% CI 1.7-7.3). The prediction model had an optimism-corrected concordance index of 0.71.
  
  
  CONCLUSIONS
  A small but sizable proportion of patients with TKA had persistent mobility limitations. Our prediction model may help to risk-stratify patients, and external validation is required before the model can be used in clinical practice.
authors.affiliation: From the Department of Physiotherapy, Singapore General Hospital, Singapore; Faculty of Health Sciences, Australian Catholic University, Victoria, Australia.Y.H. Pua, PhD, Department of Physiotherapy, Singapore General Hospital; F.J. Seah, MS, Department of Physiotherapy, Singapore General Hospital; R.A. Clark, PhD, Faculty of Health Sciences, Australian Catholic University; C.L. Poon, MS, Department of Physiotherapy, Singapore General Hospital; J.W. Tan, BSc, Department of Physiotherapy, Singapore General Hospital; H.C. Chong, BSc, Department of Physiotherapy, Singapore General Hospital. puayonghao@gmail.com.
authors.forename: Yong-Hao
authors.initials: YH
authors.lastname: Pua
authors.affiliation: From the Department of Physiotherapy, Singapore General Hospital, Singapore; Faculty of Health Sciences, Australian Catholic University, Victoria, Australia.Y.H. Pua, PhD, Department of Physiotherapy, Singapore General Hospital; F.J. Seah, MS, Department of Physiotherapy, Singapore General Hospital; R.A. Clark, PhD, Faculty of Health Sciences, Australian Catholic University; C.L. Poon, MS, Department of Physiotherapy, Singapore General Hospital; J.W. Tan, BSc, Department of Physiotherapy, Singapore General Hospital; H.C. Chong, BSc, Department of Physiotherapy, Singapore General Hospital.
authors.forename: Felicia Jie-Ting
authors.initials: FJ
authors.lastname: Seah
authors.affiliation: From the Department of Physiotherapy, Singapore General Hospital, Singapore; Faculty of Health Sciences, Australian Catholic University, Victoria, Australia.Y.H. Pua, PhD, Department of Physiotherapy, Singapore General Hospital; F.J. Seah, MS, Department of Physiotherapy, Singapore General Hospital; R.A. Clark, PhD, Faculty of Health Sciences, Australian Catholic University; C.L. Poon, MS, Department of Physiotherapy, Singapore General Hospital; J.W. Tan, BSc, Department of Physiotherapy, Singapore General Hospital; H.C. Chong, BSc, Department of Physiotherapy, Singapore General Hospital.
authors.forename: Ross Allan
authors.initials: RA
authors.lastname: Clark
authors.affiliation: From the Department of Physiotherapy, Singapore General Hospital, Singapore; Faculty of Health Sciences, Australian Catholic University, Victoria, Australia.Y.H. Pua, PhD, Department of Physiotherapy, Singapore General Hospital; F.J. Seah, MS, Department of Physiotherapy, Singapore General Hospital; R.A. Clark, PhD, Faculty of Health Sciences, Australian Catholic University; C.L. Poon, MS, Department of Physiotherapy, Singapore General Hospital; J.W. Tan, BSc, Department of Physiotherapy, Singapore General Hospital; H.C. Chong, BSc, Department of Physiotherapy, Singapore General Hospital.
authors.forename: Cheryl Lian-Li
authors.initials: CL
authors.lastname: Poon
authors.affiliation: From the Department of Physiotherapy, Singapore General Hospital, Singapore; Faculty of Health Sciences, Australian Catholic University, Victoria, Australia.Y.H. Pua, PhD, Department of Physiotherapy, Singapore General Hospital; F.J. Seah, MS, Department of Physiotherapy, Singapore General Hospital; R.A. Clark, PhD, Faculty of Health Sciences, Australian Catholic University; C.L. Poon, MS, Department of Physiotherapy, Singapore General Hospital; J.W. Tan, BSc, Department of Physiotherapy, Singapore General Hospital; H.C. Chong, BSc, Department of Physiotherapy, Singapore General Hospital.
authors.forename: John Wei-Ming
authors.initials: JW
authors.lastname: Tan
authors.affiliation: From the Department of Physiotherapy, Singapore General Hospital, Singapore; Faculty of Health Sciences, Australian Catholic University, Victoria, Australia.Y.H. Pua, PhD, Department of Physiotherapy, Singapore General Hospital; F.J. Seah, MS, Department of Physiotherapy, Singapore General Hospital; R.A. Clark, PhD, Faculty of Health Sciences, Australian Catholic University; C.L. Poon, MS, Department of Physiotherapy, Singapore General Hospital; J.W. Tan, BSc, Department of Physiotherapy, Singapore General Hospital; H.C. Chong, BSc, Department of Physiotherapy, Singapore General Hospital.
authors.forename: Hwei-Chi
authors.initials: HC
authors.lastname: Chong
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee; D005260:Female; D005684:Gait; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D020370:Osteoarthritis, Knee / Q000503:physiopathology* / Q000601:surgery; D016059:Range of Motion, Articular / Q000502:physiology; D020127:Recovery of Function / Q000502:physiology*; D018570:Risk Assessment; D016138:Walking / Q000502:physiology*
keywords: KNEE; MOBILITY LIMITATIONS; PROGNOSIS; REPLACEMENT