Simon Décary1, Pierre Frémont2, Bruno Pelletier3, Michel Fallaha3, Sylvain Belzile4, Johanne Martel-Pelletier5, Jean-Pierre Pelletier5, Debbie Feldman6, Marie-Pierre Sylvestre7, Pascal-André Vendittoli8, François Desmeules9. 1. School of Rehabilitation, Faculty of Medicine, University of Montreal, Montreal, Quebec, Canada; Orthopaedic Clinical Research Unit, Maisonneuve-Rosemont Hospital Research Center, Centre intégré universitaire de santé et de services sociaux de l'Est-de-l'Île-de-Montréal, Montreal, Quebec, Canada. Electronic address: decary.simon@gmail.com. 2. Department of Rehabilitation, Faculty of Medicine, Laval University, Quebec City, Quebec, Canada. 3. Department of Surgery, Maisonneuve-Rosemont Hospital, University of Montreal, Montreal, Quebec, Canada; Centre intégré universitaire de santé et de services sociaux de l'Est-de-l'Île-de-Montréal, Montreal, Quebec, Canada. 4. Department of Surgery, Laval University Hospital Center (CHUL), Laval University, Quebec, Quebec, Canada. 5. Osteoarthritis Research Unit, University of Montreal Hospital Research Center (CRCHUM), Montreal, Quebec, Canada. 6. School of Rehabilitation, Faculty of Medicine, University of Montreal, Montreal, Quebec, Canada. 7. University of Montreal Hospital Research Center (CRCHUM), Montreal, Quebec, Canada; Department of Social Preventive Medicine, School of Public Health, Université de Montréal, Montreal, Quebec, Canada. 8. Orthopaedic Clinical Research Unit, Maisonneuve-Rosemont Hospital Research Center, Centre intégré universitaire de santé et de services sociaux de l'Est-de-l'Île-de-Montréal, Montreal, Quebec, Canada; Department of Surgery, Maisonneuve-Rosemont Hospital, University of Montreal, Montreal, Quebec, Canada; Centre intégré universitaire de santé et de services sociaux de l'Est-de-l'Île-de-Montréal, Montreal, Quebec, Canada. 9. School of Rehabilitation, Faculty of Medicine, University of Montreal, Montreal, Quebec, Canada; Orthopaedic Clinical Research Unit, Maisonneuve-Rosemont Hospital Research Center, Centre intégré universitaire de santé et de services sociaux de l'Est-de-l'Île-de-Montréal, Montreal, Quebec, Canada.
Abstract
OBJECTIVE: To assess the validity of diagnostic clusters combining history elements and physical examination tests to diagnose or exclude patellofemoral pain (PFP). DESIGN: Prospective diagnostic study. SETTINGS: Orthopedic outpatient clinics, family medicine clinics, and community-dwelling. PARTICIPANTS: Consecutive patients (N=279) consulting one of the participating orthopedic surgeons (n=3) or sport medicine physicians (n=2) for any knee complaint. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: History elements and physical examination tests were obtained by a trained physiotherapist blinded to the reference standard: a composite diagnosis including both physical examination tests and imaging results interpretation performed by an expert physician. Penalized logistic regression (least absolute shrinkage and selection operator) was used to identify history elements and physical examination tests associated with the diagnosis of PFP, and recursive partitioning was used to develop diagnostic clusters. Diagnostic accuracy measures including sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios with associated 95% confidence intervals (CIs) were calculated. RESULTS: Two hundred seventy-nine participants were evaluated, and 75 had a diagnosis of PFP (26.9%). Different combinations of history elements and physical examination tests including the age of participants, knee pain location, difficulty descending stairs, patellar facet palpation, and passive knee extension range of motion were associated with a diagnosis of PFP and used in clusters to accurately discriminate between individuals with PFP and individuals without PFP. Two diagnostic clusters developed to confirm the presence of PFP yielded a positive likelihood ratio of 8.7 (95% CI, 5.2-14.6) and 3 clusters to exclude PFP yielded a negative likelihood ratio of .12 (95% CI, .06-.27). CONCLUSIONS: Diagnostic clusters combining common history elements and physical examination tests that can accurately diagnose or exclude PFP compared to various knee disorders were developed. External validation is required before clinical use.
OBJECTIVE: To assess the validity of diagnostic clusters combining history elements and physical examination tests to diagnose or exclude patellofemoral pain (PFP). DESIGN: Prospective diagnostic study. SETTINGS: Orthopedic outpatient clinics, family medicine clinics, and community-dwelling. PARTICIPANTS: Consecutive patients (N=279) consulting one of the participating orthopedic surgeons (n=3) or sport medicine physicians (n=2) for any knee complaint. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: History elements and physical examination tests were obtained by a trained physiotherapist blinded to the reference standard: a composite diagnosis including both physical examination tests and imaging results interpretation performed by an expert physician. Penalized logistic regression (least absolute shrinkage and selection operator) was used to identify history elements and physical examination tests associated with the diagnosis of PFP, and recursive partitioning was used to develop diagnostic clusters. Diagnostic accuracy measures including sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios with associated 95% confidence intervals (CIs) were calculated. RESULTS: Two hundred seventy-nine participants were evaluated, and 75 had a diagnosis of PFP (26.9%). Different combinations of history elements and physical examination tests including the age of participants, knee pain location, difficulty descending stairs, patellar facet palpation, and passive knee extension range of motion were associated with a diagnosis of PFP and used in clusters to accurately discriminate between individuals with PFP and individuals without PFP. Two diagnostic clusters developed to confirm the presence of PFP yielded a positive likelihood ratio of 8.7 (95% CI, 5.2-14.6) and 3 clusters to exclude PFP yielded a negative likelihood ratio of .12 (95% CI, .06-.27). CONCLUSIONS: Diagnostic clusters combining common history elements and physical examination tests that can accurately diagnose or exclude PFP compared to various knee disorders were developed. External validation is required before clinical use.