Reliability of methods used to evaluate lower limb malalignments: a systematic review

Abstract

Background: Common malalignments of the lower extremities are: increased subtalar pronation/supination, leg length discrepancy, genu recurvatum, increased Q angle, increased femoral antetorsion/retrotorsion and increased tibial torsion. The evaluation of each malalignment can be conducted with a variety of methods, making difficult the decision of the most reliable one, regarding the smallest error of measurement (SEM). Purpose: The main objective of the present study was to systematically review the existing reliability data on lower limb malalignment measurement. Given the clinical significance of malalignment assessment the study provided conclusive evidence for the variousmethods utilized for physical therapy practice. Methods: A structured research was conducted in PUBMED, CINAHL, PEDro and in The Cochrane Database, using the following keywords: quadriceps angle, navicular drop, rearfoot angle, leg length, discrepancy, genu recurvatum and asymmetry. 421 articles were found of which 41 were eventually included. The Critical Appraisal Skills Programme (CASP) was used to evaluate these articles. Results: 1) Rearfoot angle: No clear conclusions could be drawn for the methods used to measure rearfoot angle. The most reliable method (both for intraand inter examiner reliability) seemed to be the rearfoot angle measurement in relation to the sagittal plane when calculated as the difference between the angle measured with the subtalar joint in neutral and resting position (ICC= 0.85–0.91). 2) Navicular drop: It was difficult to propose a method that is superior to others.With the exception of navicular drift, the methods provided in the literature have moderate to high intra-tester reliability (ICC= 0.73–0.96) but disagreements were evident regarding the inter-tester reliability. A major issue in the measurement of navicular drop was the SEM, because the range of valuesmeasuredwas small and the same applies for SEM. Results from the studies could not clarify if any of the methods previously described appeared to have acceptably small SEM. 3) Leg length discrepancy: Controversial evidence was found regarding the reliability of both direct and indirect methods and further research is needed. 4) Genu recurvatum: Insufficient evidence currently exists due to small number (only 2) of studies assessing this clinical presentation. 5) Q angle:Measurement from the upright position without quadriceps isometric contraction seemed to be reliable (ICC= 087–0.98). For the other methods, further research is needed. 6) Femoral antetorsion/retrotorsion: Ryder’s test has “poor” to “fair” inter-examiner reliability (ICC= 0.45–0.74) and “good” to “high” intra-examiner reliability (ICC= 0.77–0.94). No conclusion could be made for the Femoral Torsion Index method. 7) Tibial torsion:Clear conclusions could not occur been drawn because only 5 studies were reported in the literature and no study examined all measurements. Conclusion(s): Further reliability studies should be conducted for the methods measuring malalignments. Future studies should focus on appropriate statistical analyses for calculation of SEM. Implications: This study should help physical therapists to clarify which malalignment measuring methods are reliable for use in everyday practice.