Factors affecting the intra-examiner and inter-examiner reliability of palpation for supine medial malleoli asymmetry

BackgroundMany authors in the field of osteopathy claim that identification of asymmetrical bony landmarks may be useful for identifying sacroiliac joint dysfunction, but previous studies have failed to establish acceptable inter-examiner reliability for the detection of these landmarks.ObjectiveTo examine factors that may improve the inter-examiner reliability of palpation for medial malleoli asymmetry.MethodsFive final-year osteopathic students examined two groups of five asymptomatic female subjects for supine medial malleoli symmetry in separate trials, conducted a week apart. Subjects in the first trial were not screened for any asymmetry. In Trial 2, the author screened and selected five subjects from 15 healthy volunteers who were estimated to have a medial malleoli asymmetry of greater than 4 mm, but less than 10 mm. Three rounds of assessment of medial malleoli symmetry were performed on every supine subject, by all examiners. In order to blind the examiners, subjects were covered from head to knees with a sheet, and changed tables between rounds. Examiner agreement was analysed using Cohen's weighted Kappa (κ) statistic.ResultsInter-examiner agreement for Trial 1 was fair (κ = 0.22), but was almost perfect (κ = 0.94) in Trial 2. Similarly, mean intra-examiner agreement in Trial 1 was fair (κ = 0.31), whereas it was almost perfect (κ = 0.94) in Trial 2.ConclusionIntra-examiner and inter-examiner reliability was almost perfect following subject selection for malleoli asymmetry, which suggests that clinicians can reliably detect medial malleoli asymmetries of greater than approximately 4 mm difference. The clinical usefulness of detecting medial malleoli levels and leg length inequality requires investigation.