Diagnostic validity and triage concordance of a physiotherapist compared to physicians' diagnoses for common knee disorders

Abstract

Background: Emergence of more autonomous roles for physiotherapists warrants more evidence regarding their diagnostic capabilities. Therefore, we aimed to evaluate diagnostic and surgical triage concordance between a physiotherapist and expert physicians and to assess the diagnostic validity of the physiotherapist's musculoskeletal examination (ME) without imaging. Methods: This is a prospective diagnostic study where 179 consecutive participants consulting for any knee complaint were independently diagnosed and triaged by two evaluators: a physiotherapist and one expert physician (orthopaedic surgeons or sport medicine physicians). The physiotherapist completed only a ME, while the physicians also had access to imaging to make their diagnosis. Raw agreement proportions and Cohen's kappa (k) were calculated to assess inter-rater agreement. Sensitivity (Se) and specificity (Sp), as well as positive and negative likelihood ratios (LR+/-) were calculated to assess the validity of the ME compared to the physicians' composite diagnosis. Results: Primary knee diagnoses included anterior cruciate ligament injury (n = 8), meniscal injury (n = 36), patellofemoral pain (n = 45) and osteoarthritis (n = 79). Diagnostic inter-rater agreement between the physiotherapist and physicians was high (k = 0.89; 95% CI:0.83-0.94). Inter-rater agreement for triage recommendations of surgical candidates was good (k = 0.73; 95% CI:0.60-0.86). Se and Sp of the physiotherapist's ME ranged from 82.0 to 100.0% and 96.0 to 100.0% respectively and LR+/- ranged from 23.2 to 30.5 and from 0.03 to 0.09 respectively. Conclusions: There was high diagnostic agreement and good triage concordance between the physiotherapist and physicians. The ME without imaging may be sufficient to diagnose or exclude common knee disorders for a large proportion of patients. Replication in a larger study will be required as well as further assessment of innovative multidisciplinary care trajectories to improve care of patients with common musculoskeletal disorders.