The intra- and inter-observer reliability of the physical examination methods used to assess patients with patellofemoral joint instability

Toby O. Smith, Allan Clark, Sophia Neda, Elizabeth A. Arendt, William R. Post, Ronald P. Grelsamer, David Dejour, Karl Frederik Almqvist, Simon T. Donell

Research output: Contribution to journalArticlepeer-review

42 Citations (Scopus)


Background An accurate physical examination of patients with patellar instability is an important aspect of the diagnosis and treatment. While previous studies have assessed the diagnostic accuracy of such physical examination tests, little has been undertaken to assess the inter- and intra-tester reliability of such techniques. The purpose of this study was to determine the inter- and intra-tester reliability of the physical examination tests used for patients with patellar instability. Methods Five patients (10 knees) with bilateral recurrent patellar instability were assessed by five members of the International Patellofemoral Study Group. Each surgeon assessed each patient twice using 18 reported physical examination tests. The inter- and intra-observer reliability was assessed using weighted Kappa statistics with 95% confidence intervals. Results The findings of the study suggested that there were very poor inter-observer reliability for the majority of the physical tests, with only the assessments of patellofemoral crepitus, foot arch position and the J-sign presenting with fair to moderate agreement respectively. The intra-observer reliability indicated largely moderate to substantial agreement between the first and second tests performed by each assessor, with the greatest agreement seen for the assessment of tibial torsion, popliteal angle and the Bassett's sign. Conclusions For the common physical examination tests used in the management of patients with patellar instability inter-observer reliability is poor, while intra-observer reliability is moderate. Standardization of physical exam assessments and further study of these results among different clinicians and more divergent patient groups is indicated.
Original languageEnglish
Pages (from-to)404–410
Number of pages7
JournalThe Knee
Issue number4
Publication statusPublished - Aug 2012

Cite this