Favouring footwear or being barefoot? Gaining insights to the possibility of barefoot activities to aid osteoarthritis of the knee

“Most people assume that any comfortable shoe must also be healthy”

Daniel Lieberman 2014 p 232

The Story of the Human Body. Evolution, health and disease. Penguin Books.

Footwear is so much a part of modern lifestyle that people do not give a second thought to putting on shoes, trainers or sandals to go outside. In fact, footwear feels so natural that the thought of walking barefoot around the concrete pavements of a city would be enough to curl our toes! Footwear provides protection and comfort, but should we be careful not to mistake comfort for wellbeing?

Our Palaeolithic ancestors were habitually barefoot despite the possibility of stepping on sharp objects, toxic substances or ‘critters that bite’. Palaeolithic feet adapted to these potential dangers by developing a protective layer of thick skin on the sole. If modern day city dwellers dared to walk barefoot for a prolonged period of time, they too would develop thicker skin of the soles of their feet. Eventually, being barefoot would likely feel ‘normal’.

Being barefoot increases activity in muscles of the foot, ankle, knee and hip and over time this strengthens joints, making movement more efficient and improving stability. Barefoot also exposes the skin of the feet to the surface of the ground and to variations in environmental temperature. This increases sensory input to the central nervous system stimulating responses that improve the awareness of the position of the body (proprioception) aiding stability whilst walking and running. The greater sensory input also reduces pain. The ‘natural’ sensory input associated with being barefoot is diminished when wearing footwear, especially footwear that is cushioned and covers the whole foot.

The first known human footwear appeared approximately 30,000 years ago as a means to protect feet from injuries associated with stepping on harmful objects and exposure to extremes of temperature, such as hot sand or cold snow. Often, modern footwear has cushioned soles to absorb ground reaction force and reduce forces transmitted through load-bearing joints. However, footwear creates a barrier between the skin of the foot and the surface of the ground resulting in a reduction in ‘natural’ sensory input to the body. This affects proprioception and the position of feet relative to the ground resulting in alterations in stride length, cadence and forces through joints when compared with being barefoot. Manufacturers have to consider the influence absorption of impact, stability and protection in the design of footwear on the health of the feet and lower limbs.

Recently, there has been interest in whether being barefoot influences knee pain associated with osteoarthritis. Osteoarthritis can affect load-bearing joints in the lower limb, resulting in pain, stiffness and reduced movement. An estimated 4.11 million people over the age of 45 years have osteoarthritis of the knee (Arthritis Research UK. The Musculoskeletal Calculator (prevalence data tool) 2019) and this is likely to rise in the future with an ever-ageing population. Guidelines for the management of osteoarthritis published by the National Institute for Health and Care Excellence (NICE) recommend that patients should receive individualised, self-management treatment with positive life-style changes including exercise, weight loss and suitable footwear. Characteristics of conventional footwear detrimental to the health of feet and joints of the lower limb are listed in the Table.

Table. Characteristics of conventional footwear.

Excessive loading of the inside of the knee joint has been shown to create compressive forces contributing to pain and physical dysfunction in people with osteoarthritis of the knee. Suitable footwear is considered to be supportive and cushioned to absorb impact to the feet from the ground because such footwear reduces load at the knee joint. Paradoxically, research suggests that walking barefoot may also reduce load at the knee by and altering gait pattern and increasing lower limb muscle activity and strength. Some research has found that walking barefoot alleviates common signs and symptoms associated with osteoarthritis, including pain along the medial aspect of the knee. In addition, increased sensory input from exposed skin of the feet may improve proprioception and reduce pain. Interestingly, health care practitioners recommend that patients recovering from injuries that involve musculoskeletal structures perform exercises whilst barefoot to develop proprioceptive sense. Runners may include barefoot training to prevent injury, or when returning from injury as part of a rehabilitation package.

A potential role for barefoot exercises including walking for people with osteoarthritis of the knee seems to be contradictory to advice recommended by NICE and merits further exploration. Presently, we are undertaking a programme of research to gain insights into the biomechanical and physiological characteristics of barefoot activities in people with osteoarthritis in the lower limbs. The research involves the following stages:

1. To review existing literature on the biomechanics of walking barefoot or shod in people with osteoarthritis of the knee
2. To survey healthcare professionals about their attitudes, beliefs and use of footwear for the management of knee osteoarthritis.
3. To conduct some laboratory studies to compare the biomechanics and foot morphology of barefoot locomotion in patients with and without knee osteoarthritis.

It is hoped that this research will be the first steps in deciding whether being barefoot be considered as part of an individualised self-management care plan for people with osteoarthritis of the knees.