Validité et fidélité de la combinaison de l’anamnèse et de l’examen physique pour le diagnostic des pathologies communes au genou

Knee complaints are among the most common reasons for consulting a healthcare practitioner. Common knee disorders include those of traumatic onset such as anterior cruciate ligament or meniscal tears, or those of progressive onset such as degenerative meniscal tears, knee osteoarthritis or patellofemoral pain syndrome. An early diagnosis to guide toward an efficient management is advocated to prevent persistence of pain, functional limitations and loss of quality of life in affected individuals. However, evidence currently shows an overreliance on medical imaging tests and inappropriate orthopaedic surgery referrals, thus delaying initiation of treatment. Evidence is currently limited concerning the validity and reliability of combining history elements and physical examination tests to support the differential diagnosis of common knee disorders.  To answer this evidence gap, this thesis had two objectives: 1- to assess inter-rater diagnostic agreement between a physiotherapist using only a standardized musculoskeletal examination and expert physicians using a musculoskeletal examination in combination with imaging tests for the diagnosis of common knee disorders; 2- to assess the diagnostic validity of clusters combining history elements and physical examination tests and produce a series of tools to support the differential diagnosis of four common knee disorders.  We prospectively recruited two hundred and seventy-nine participants presenting 359 primary and secondary diagnoses including: 43 participants with an anterior cruciate ligament tear, 80 subjects had a meniscal tear, 129 suffered from knee osteoarthritis, 75 were diagnosed with patellofemoral pain syndrome and 32 presented other knee diagnoses. The physiotherapist achieved high inter-rater agreement with the expert physicians for the diagnosis of common knee disorders (k= 0.89; 95%CI:0.83-0.94).   Multiple clusters combining history elements and physical examination tests were developed to support the differential diagnosis of knee disorders. Our results show that an individual consulting for a knee complaint following trauma during a pivot and describing a “popping sensation” during the trauma as well as showing a positive Lachman or pivot shift tests has a high probability of having an anterior cruciate ligament tear with a positive likelihood ratio of 38.4 (95%CI: 16.0-92.5). If this individual consulting for a knee complaint following trauma during a pivot experience medially located knee pain, confirmed with medial joint line tenderness at palpation, the subject has a high probability of having a meniscal tear of traumatic origin with a positive likelihood ratio of 8.9 (95%CI: 6.1-13.1).  An individual consulting for a complaint of progressive onset with isolated medially located pain during activities requiring a pivot, who also presents a normal knee alignment or full passive knee flexion, has a moderate probability of having a degenerative meniscal tear with a positive likelihood ratio of 6.4 (95%CI: 4.0-10.4). If this individual complaining of knee pain of progressive onset is older than 50 years old, has a body mass index higher than 30 and at physical examination presents knee crepitus at palpation, a valgus or varus knee misalignment or a restricted passive knee extension, he has a high probability of having symptomatic knee osteoarthritis with a positive likelihood ratio of 13.6 (95%CI: 6.5-28.4). Lastly, an individual consulting for isolated anterior knee pain with difficulty descending stairs, palpable patellar facets tenderness and full passive knee extension has a high probability of having a patellofemoral pain syndrome with a positive likelihood ratio of 8.7 (95%CI: 5.2- 14.6).  Overall, the results demonstrated high inter-rater diagnostic concordance between providers and that combining selected history elements and physical examination tests was moderately to highly valid to support the differential diagnosis of common knee disorders. The proposed diagnostic clusters will require external validation in various clinical contexts, including primary care, before widespread implementation in clinical practice.

Keyphrases: Diagnostic, Knee, Diagnosis, History elements, Physical examination, Anterior cruciate ligament, Meniscus, Knee osteoarthritis, Patellofemoral pain syndrome