ICAOR 2006 Factors influencing intra-examiner and inter-examiner reliability of palpation for supine medial malleoli asymmetry

Introduction: Some authors in the field of osteopathy claim that the detection of asymmetry of bony landmarks is useful for identifying sacroiliac dysfunction. 1,2 A previous study 3 found that the medial malleoli was the landmark with the highest inter-examiner agreement, and, although agreement was less than acceptable for a clinical test, examiner fatigue caused by the repeated examination of many landmarks may have adversely affected examiner reliability. The present study aimed to examine ways in which the reliability of palpation for medial malleoli asymmetry can be improved. Methods: Five final-year osteopathic students examined five asymptomatic female subjects for supine medial malleoli symmetry in two trials, conducted one week apart. Subjects in the first trial were not screened for any asymmetry, but for Trial 2, the author screened and selected five subjects from approximately 15 healthy volunteers, who appeared to have a medial malleoli asymmetry of greater than 4 mm, but less than 10 mm. Three assessments of medial malleoli symmetry were performed on every supine subject, by all examiners. Examiner agreement was analysed using Cohen’s weighted Kappa (k) statistic. Results: Inter-examiner agreement for Trial 1 was only fair (k ¼ 0.22), but was almost perfect (k ¼ 0.94) in Trial 2. Similarly, mean intra-examiner agreement in Trial 1 was fair (k ¼ 0.31), whereas it was almost perfect (k ¼ 0.94) in Trial 2. Conclusions: Inter-examiner agreement in Trial 1 was similar to a previous study where examiners assessed six landmarks and one motion test in 10 subjects, which suggests that examiner fatigue did not influence agreement. Intra and inter-examiner reliability was almost perfect for Trial 2, 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 still requires investigation.