特制运动鞋对膝骨关节炎患者有益

芝加哥拉什大学风湿病科的Najia Shakoor医生及其合作者初步研究发现，穿6个月的特制运动鞋可明显减轻膝盖的负荷，即使在受试者此后再穿普通鞋时亦如此，这表明这种鞋存在步态适应，长期用之可改变步态，可能对膝骨关节炎患者的治疗有益。

这种运动鞋是由Shakoor医生与Roy Lidkte医生发明的，在足部主要弯曲点有些沟壑，能使足部产生自然的“赤脚样”运动。以前的一项研究显示，这种鞋能模拟赤脚步行时的无负荷效应。有证据显示，膝骨关节炎患者的膝关节负荷增大与“放射学严重病变、疾病进展及疼痛”有关联，因此“减小膝部的负荷可能会产生明显的症状改善。”此鞋的专利由拉什大学医学中心所有，若成功的话，该大学将会因许可协议而获得付款，而Shakoor医生和Lidtke医生也将得到部分付款。

该研究在内侧间室膝骨关节炎患者中评估了这种鞋对步态运动学的影响，共招募了16例膝骨关节炎患者，平均年龄为57岁。研究者在6、12及24周时测量症状较重一侧的膝外展运动(KAM，衡量内侧间室膝负荷的一项合理指标，与膝骨关节炎的疼痛和进展有关联)。患者穿这种鞋子的时间为每天至少6小时，每周穿6天(平均7小时/天)。共有10例患者完成了研究；其余6例因为无效而退出研究或未返回接受后续随访，其结果也被纳入了分析。

结果显示，受试者24周时的KAM较基线穿普通鞋时的基值降低了18%，有显著的统计学差异。此外，在24周时，他们穿普通鞋测得的KAM较基值降低了11%，徒步行走时测得的KAM较基值降低了10%，提示穿特制鞋可能“重新调整了”步态。 其他研究结果包括受累膝部疼痛明显改善，衡量指标为西安大略大学和麦克马斯特大学骨关节炎指数(WOMAC)。

这项原理循证研究为膝骨关节炎治疗中鞋类选择的重要性提供了证据支持。在既往研究中，与穿普通鞋相比，步行时赤脚和穿模拟赤脚力学设计的鞋与膝盖负荷减小有关，但研究者并未确定特制鞋在较长时间范围内的作用。

研究者承认本研究存在局限性，包括样本量小和仅随访6个月等。

本研究由关节炎基金会资助。

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By: ELIZABETH MECHCATIE, Internal Medicine News Digital Network

A pilot study involving 16 people with osteoarthritis of the knee found that wearing specially designed shoes for 6 months significantly reduced knee loading, providing evidence that specialized footwear might be useful in the management of patients with OA of the knee, according to the investigators.

The improvements seen with the use of the shoes suggest "that footwear can be used as a mechanical device to achieve beneficial adaptations and alteration of gait with chronic use," said Dr. Najia Shakoor of the rheumatology section at Rush University, Chicago, and her associates.
 
In addition, after wearing the shoes for 6 months, the reduced load was evident even when the participants wore conventional shoes, suggesting "the presence of a gait adaptation with reductions in loading present even once the mobility shoes are removed," they added (Arthritis Rheum. 2013 April 10 [doi:10.1002/art.37896]).

Invented by Dr. Shakoor and one of her coauthors, Dr. Roy Lidtke, who is also at Rush, the mobility shoe has grooves that are "strategically placed at major flexion points of the foot to allow for natural, ‘barefoot-like’ movement of the foot," they said. In a previous study, they showed that the shoe mimicked the unloading effect of walking barefoot. They referred to evidence that elevated load on the knee joint in people with knee OA is associated with "radiographic severity, disease progression, and pain," and therefore, "reduction of loading at the knee may yield significant symptomatic benefits."

The patent for the shoe is owned by Rush University Medical Center, and if successful, the university will be paid for the licensing agreement and Dr. Shakoor and Dr. Lidtke also will receive some of the payments.

The study evaluated the effects of the shoes on the kinematics of gait in patients with medial compartment knee OA who were a mean age of 57 years. In the more symptomatic knee of each patient, the investigators measured the knee adduction moment (KAM) at 6, 12, and 24 weeks. KAM is a validated measure of medial compartment knee loading that has been associated with pain and progression of knee OA. Patients wore the shoes for at least 6 hours a day, 6 days a week (mean was 7 hours a day). Overall, 10 patients completed the study; the other 6 either dropped out because of a lack of effect or did not return for later visits; their results were included in the analysis.

At 24 weeks, the KAM was 18% lower when compared with measurements obtained at baseline, when the participants were wearing their regular shoes – a statistically significant difference. In addition, at 24 weeks, compared with baseline, the KAM was 11% lower while they were wearing their own shoes and 10% lower when walking barefoot, indicating that wearing the shoes may have "retrained" their gait, according to Dr. Shakoor and her associates.

Other findings included significant improvements in the pain of the affected knee, as measured by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC).

This proof-of-principle study "provides support for the importance of footwear choice in the management of knee OA," the authors concluded. In previous studies, the authors showed that walking barefoot and wearing footwear designed to mimic barefoot mechanics was associated with reductions in knee loading, compared with wearing conventional footwear, but they had not determined the effects of the shoes over a longer period of time.

The study had limitations, including its sample size and follow-up duration of only 6 months, as well as the fact that the complete benefit of the shoes may not be clear until they are worn in a larger group of people for a longer period of time, the authors pointed out.

The study was supported by the Arthritis Foundation.