Orthopaedic Surgery Research Unit, Aalborg University Hospital, Aalborg, Denmark.
J Foot Ankle Res. 2014 Feb 13;7(1):12. doi: 10.1186/1757-1146-7-12.
Increased navicular drop is associated with increased risk of lower extremity overuse injuries and foot orthoses are often prescribed to reduce navicular drop. For laboratory studies, transparent shoes may be used to monitor the effect of orthoses but no clinically feasible methods exist. We have developed a stretch-sensor that allows for in-shoe measurement of navicular drop but the reliability and validity is unknown. The purpose of this study was to investigate: 1) the reliability of the stretch-sensor for measuring navicular drop, and 2) the concurrent validity of the stretch-sensor compared to the static navicular drop test.
Intra- and inter-rater reliability was tested on 27 participants walking on a treadmill on two separate days. The stretch-sensor was positioned 20 mm posterior to the tip of the medial malleolus and 20 mm posterior to the navicular tuberosity. The participants walked six minutes on the treadmill before navicular drop was measured. Reliability was quantified by the Intraclass Correlation Coefficient (ICC 2.1) and agreement was quantified by Limits of Agreement (LOA). To assess concurrent validity, static navicular drop was measured with the stretch-sensor and compared with static navicular drop measured with a ruler on 27 new participants. Linear regression was used to measure concurrent validity.
The reliability of the stretch-sensor was acceptable for barefoot measurement (intra- and inter-rater ICC: 0.76-0.84) but lower for in-shoe measurement (ICC: 0.65). There was a significant association between static navicular drop measured with the stretch-sensor compared with a ruler (r = 0.745, p < 0.001).
This study suggests that the stretch-sensor has acceptable reliability for dynamic barefoot measurement of navicular drop. Furthermore, the stretch-sensor shows concurrent validity compared with the static navicular drop test as performed by Brody. This new simple method may hold promise for both clinical assessment and research but more work is needed before the method can be recommended.
足舟骨下降与下肢过度使用损伤的风险增加有关，因此常开具矫形鞋垫来降低足舟骨下降。在实验室研究中，通常使用透明鞋来监测矫形鞋垫的效果，但目前还没有临床可行的方法。我们已经开发出一种拉伸传感器，可以在鞋内测量足舟骨下降，但该传感器的可靠性和有效性尚不清楚。本研究的目的是调查：1）拉伸传感器测量足舟骨下降的可靠性，以及 2）与静态足舟骨下降测试相比，拉伸传感器的同时效度。
27 名参与者在两天内在跑步机上行走，以测试内和间测试者的可靠性。拉伸传感器位于内踝尖后 20mm 和舟状骨结节后 20mm 处。参与者在跑步机上行走六分钟后测量足舟骨下降。可靠性通过组内相关系数（ICC 2.1）进行量化，一致性通过界限协议（LOA）进行量化。为了评估同时效度，使用拉伸传感器测量静态足舟骨下降，并与 27 名新参与者使用标尺测量的静态足舟骨下降进行比较。线性回归用于测量同时效度。
拉伸传感器在赤脚测量时的可靠性是可以接受的（内和间测试者 ICC：0.76-0.84），但在鞋内测量时的可靠性较低（ICC：0.65）。使用拉伸传感器测量的静态足舟骨下降与使用标尺测量的静态足舟骨下降之间存在显著关联（r=0.745，p<0.001）。
本研究表明，拉伸传感器在动态赤脚测量足舟骨下降方面具有可接受的可靠性。此外，与 Brody 进行的静态足舟骨下降测试相比，拉伸传感器具有同时效度。这种新的简单方法可能在临床评估和研究中都有前途，但在该方法被推荐之前还需要做更多的工作。
