Validation of three classification systems for posterior malleolus fractures of the ankle.

PURPOSE: A number of classification systems exist for posterior malleolar ankle fractures. The user reliability of these classification systems remains unclear. The primary aim of this study was to evaluate the reliability of three commonly utilised classification systems for fractures of the posterior malleolus. METHODS: Imaging of 60 patients across 2 hospitals with ankle fractures including a posterior malleolar fragment was identified. All patients had undergone plain radiographs and computed tomography of their injured ankle as part of their normal standard of care. 9 surgeons including pre-resident/registrar level, resident/registrar level, and attending/consultant level applied the Haraguchi, Bartonícek, and Mason classifications to these fractures, at two timepoints, at least 4 weeks apart. The order was randomised between assessments. Inter-rater reliability was assessed using Fleiss' κ and standard error (SE). Intra-rater reliability was assessed using Cohen's κ and standard error (SE). RESULTS: Inter-rater reliability (Fleiss' κ) was calculated for the Haraguchi classification as 0.588 (SE 0.023), for the Bartonícek classification as 0.626 (SE 0.019), and the Mason classification as 0.541 (SE 0.098). Intra-rater reliability (Cohen's κ) was 0.761 (SE 0.098) for the Haraguchi classification, 0.761 (SE 0.091) for the Bartonícek, classification, and 0.724 (SE 0.096) for the Mason classification. CONCLUSIONS: This study reports the inter-rater and intra-rater reliability for three classification systems for posterior malleolus fractures. Based on definitions by Landis and Koch (Biometrics 33:159-174, 1977), inter-rater reliability was rated as 'moderate' for the Haraguchi and Mason classifications and 'substantial' for the Bartonícek classification. Similarly, the intra-rater reliability was rated as 'substantial' for all three classifications.

The pivot shift test is of limited clinical relevance in the arthritic anterior cruciate ligament-deficient knee.

The pivot shift test is used to assess the integrity of the anterior cruciate ligament (ACL). This test has been shown to be highly sensitive in detecting instability in knees with complete ACL rupture. However, in the presence of osteoarthritis, the rotation and subluxation required for the pivot shift to be effective can be limited and therefore is likely to impact upon the reliability of this test. We performed the pivot shift test on 50 patients, under general anesthesia, prior to total knee replacement and then recorded the integrity of the ACL intraoperatively. This allowed us to assess the accuracy of this test in the presence of significant osteoarthritis. Of the 50 knees tested, none had a positive pivot shift test preoperatively; however, 14% of the knees included in the study had a completely ruptured ACL. This gives a sensitivity of 0% and a specificity of 1% for the pivot shift test for ACL ruptures in the presence of established osteoarthritis. We conclude that the pivot shift test may not be a reliable test for ACL function in the presence of symptomatic arthritis of the knee.