Knee osteoarthritis (OA) is one of five leading causes of disability among adults. About 25% of people with knee OA have pain on walking and have difficulty doing major activities of daily living (ADLs) such as walking 1/4 mile, climbing stairs, or kneelin. Mechanical loading that occurs at the medial tibiofemoral knee joint is strongly associated with the development and progression of knee OA. The knee adduction moment is one measure of knee loading that is associated with medial compartment OA presence, radiographic disease severity, rate of progression, and the presence of OA symptoms. One conservative treatment method for OA patients is the prescription of a walking cane. Studies have shown cane use contralateral to the affected knee can significantly reduce the medial load experienced by the joint if proper cane loading is achieved. Proper cane loading implies the cane supports a substantial portion of one's body weight, e.g. 15% body weight. Recent work has shown that the greater the load placed on the cane the greater the resulting reduction in medial knee load. The importance of reducing the medial knee load is significant. For example, a 20% increase in peak KAM was shown to lead to a 6-fold increase in the risk of knee osteoarthritis over a six-year period. While walking canes can be effective if used correctly there is evidence that very few patients receive instruction on how to use a cane. Sixty seven percent of senior living community cane users self- prescribe their canes and 82% receive no education or demonstration from medical professionals. Therefore we propose that the development of a walking cane that is intuitive to use, encourages greater cane loading, and shown to be more effective at reduce knee loading than a conventional cane would be beneficial for the knee OA patient population.
We aim to develop and validate a smart cane that can facilitate proper cane loading by guiding the user to maintain greater longitudinal forces through the cane. The smart cane uses real-time vibrotactile biofeedback to inform the user when proper cane load has been achieved. A first prototype of the smart cane has already been developed which signals the user via handle vibration when a specific cane load, expressed in terms of percent body weight has been applied to the cane. For this study, we propose to evaluate the smart cane in terms of the its ability to increase cane loading and decrease knee loading as compared to a conventional walking cane. Specifically, we aim to demonstrate that, 1) cane loading is greater when walking with a smart cane as compared to walking with a conventional cane and 2) the KAM is reduced when walking with a smart cane as compared to walking with a conventional cane. We hypothesis that H1) mean peak cane load when using a smart cane is greater than mean peak cane load when using a conventional cane, H2) mean peak KAM when using a smart cane is less than mean peak KAM when using a conventional cane, and that mean peak cane loading will be greater (H3.1) and KAM will be reduced (H3.2) when comparing regular cane use before and one week after smart cane practice. We believe that simple biofeedback technologies can be used to improve the efficacy of walking canes. Relaying cane force to the user in real-time may allow knee OA patients to more accurately and consistently load their walking cane to the appropriate level. This consistent long term proper cane use has the potential to result in persistent reduction of knee loading resulting in a decrease in knee pain and improved knee joint function. Developing more effective conservative treatment strategies that can slow the progression of joint deterioration would benefit those suffering from knee OA and improve their quality of life.
In the United States an estimated 9 million adults have symptomatic knee OA, which can cause pain and disrupt one's activities of daily living. As our Veterans continue to age the prevalence of knee OA will also increase. Walking canes are often prescribed to knee OA patients; however, they are easy to improperly use resulting in ineffective knee OA management. Over the last few hundred years walking canes have barely changed yet embedded computational power, sensors and actuators have become miniaturized and inexpensive. This proposal will determine the efficacy of a novel smart walking cane that we have developed. Improving conservative treatment strategies of knee OA in Veterans is one of the overall objectives of this research. Veterans are expected to greatly benefit from the proposed study, which will yield key knowledge needed to advance a new generation of walking canes that slow disease progression.