We commonly prescribe walking boots, sometimes referred to as controlled ankle motion (CAM) walkers, for the treatment of diabetic foot ulcerations, fractures and tendon injuries of the lower extremity. Clinicians continue to be baffled and frustrated by the fact that, in spite of the significance of these pathologies, patients have very poor adherence in wearing these devices that are a vital part of the treatment plan.
An eye-opening study by Armstrong and colleagues showed that patients who were prescribed walking boots to treat active diabetic foot ulcerations only wore the devices 28 percent of the time they were ambulating.1 Many have speculated on why patients are non-adherent in the use of walking boots, including the fact that the devices are bulky and a perception that they may negatively affect balance.2
Despite the perception that walking boots impair balance, few studies exist to validate this notion. Several studies have shown the negative effects of solid ankle-foot orthoses (AFOs) on balance while articulated AFOs in these same studies showed no negative effects but actual improvements in balance.3,4 Researchers speculate that solid AFOs and walking boots negatively affect balance by limiting ankle joint motion, which decreases proprioceptive feedback from ankle joint receptors and muscle spindles around the ankle joint while also limiting the “ankle strategy” for correcting postural alignment.5,6
Even healthy patients who have no balance impairments appear to be non-adherent in wearing walking boots on a daily basis. In my own practice, I am always concerned about the fact that many patients report that walking boots cause pain in proximal joints including the knees, hips and spine. One reason for this is the fact that walking boots establish a limb length discrepancy, which we often overlook when fitting the devices to the patient.
A recently published study in the Journal of Prosthetics and Orthotics has shown some interesting insight into how walking boots affect balance and limb length compensations.7 Goodworth and co-workers conducted balance tests on patients wearing walking boots with and without heel lifts applied to the contralateral limb and compared them to people without walking boots. As expected, the wearing of a walking boot on one lower extremity caused significant compromise of balance during quiet stance, functional reach tests and perturbed walking tests. Applying a heel lift to the contralateral foot reduced the negative effects of the walking boot but only in the quiet stance test.
The authors of this study speculated that the negative effects on balance, which they measured when patients wore a walking boot, were due to decreased ankle motion as well as reduced surface contact with the floor due to the rocker bottom of the boot and a leg length discrepancy imposed by the sole of the boot. At least some of the negative balance effects can improve with the use of a heel lift on the opposite foot customized to the patient to ensure leveling of the pelvis in the frontal plane.
The take-home message from this study as well as others cited below is the fact that most of the offloading strategies we use in clinical practice have the potential to compromise balance. This factor alone may explain the reluctance of our patients to wear immobilizing devices on a daily basis. Here are a few clinical pearls that have improved patient adherence with walking boots in my own clinical practice.
• Patient education when dispensing a walking boot is vital to improve patient adherence. The patient must recognize that balance will be affected and should take appropriate precautions such as avoiding uneven surfaces. Patients should take extra care when walking at night or during poorly illuminated conditions. While balance might be compromised, the boot is critical to healing and the patient must wear it at all times during ambulation.
• Office staff should be trained to apply a heel lift to the contralateral shoe and should visually align the pelvis during static stance to ensure that they have minimized limb length discrepancy. Patients should get instructions to make sure they feel level with any shoe or heel lift combination they wear on the contralateral foot.
• One should dispense a cane for elderly patients, neuropathic patients or any other fall risk patients for use during ambulation with a walking boot or cast.
Follow these measures for all non-articulated solid shell offloading devices including total contact casts, walking boots, solid AFOs and gauntlet braces. Not only will patient adherence with use of the devices improve but one can minimize the risk of falling or sustaining injury.
1. Armstrong DG, Lavery LA, Kimbriel HR, Nixon BP, Boulton AJ. Activity patterns of patients with diabetic foot ulceration: patients with active ulceration may not adhere to a standard pressure off-loading regimen. Diabetes Care. 2003; 26(9):2595-7.
2. Armstrong DG, Lavery LA, Wu S, et al. Evaluation of removable and irremovable cast walkers in the healing of diabetic foot wounds: a randomized controlled trial. Diabetes Care. 2005; 28(3):551-4.
3. Radtka SA, Oliveira GB, Lindstrom KE, Borders MD. The kinematic and kinetic effects of solid, hinged and no ankle-foot orthoses on stair locomotion in healthy adults. Gait Posture. 2006; 24(2):211-18.
4. Cattaneo D, Marazzini F, Crippa A, Cardini R. Do static or dynamic AFO’s improve balance? Clinical Rehabilitation. 2002; 16(8):894-899.
5. Horak FB, Nashner LM. Central programming of postural movements: adaptation to altered support-surface configurations. J Neurophysiol. 1986; 55(6):1369-1381.
6. Hof AL, Vermerris SM, Gjaltema WA. Balance responses to lateral perturbations in human treadmill walking. J Exp Biol. 2010; 213(15):2655-2664.
7. Goodworth AD, Kunsman M, DePietro V, LaPenta G, et al. Characterization of how a walking boot affects balance. J Prosthet Orthotics. 2014; 26(1):54-60.