Patients apply excessive weight when instructed to partially weight-bear but with biofeedback can learn to correct this

Abstract

Does pressure biofeedback improve the ability of patients to achieve their prescribed weight-bearing status? Randomised controlled trial. A rehabilitation centre in Israel. Adults with medical instruction to partially weight-bear after fracture or surgery affecting a single lower limb. Major cognitive impairment and neurologic disease were exclusion criteria. Randomisation of 33 participants allotted 15 to the biofeedback group and 18 to a control group. Both groups received physiotherapy for 45 minutes for 10 days. The intervention group practised appropriate weight bearing through the affected leg for 20 minutes in standing with audiovisual biofeedback. The feedback was from an insole linked to a portable auditory unit and to a stationary computer screen for visual feedback. This was followed by 15 minutes of walking training with audio feedback and a 5-minute review of the participant's weight-bearing that day. The control group practised appropriate weight bearing through the affected leg for 20 minutes in standing followed by 20 minutes of walking training, all with the biofeedback unit taking measurements but providing no feedback. However, a physiotherapist supervised the treatment and gave verbal summary feedback. Both groups concluded with 10 minutes of transfer practice and instructions in strengthening exercises for the injured limb. To test retention of any treatment effect, all auditory and visual feedback was switched off in the intervention group after the first 5 days. The primary outcome was the percentage of body weight borne through the affected leg as measured by the biofeedback unit. The target for toetouch (TT) weight bearing was ≤ 20% of body weight and the target for partial weight bearing (PWB) was 21–50% of body weight. Secondary outcomes included the Timed Up and Go test and pain rating using a visual analogue scale. At baseline, most TT participants exceeded their weight-bearing target: 49 ± 14% in the treatment group and 51 ± 21% in the control group. Similarly, most PWB participants exceeded their target at baseline: 63 ± 14% in the treatment group and 59 ± 12% in the control group. Most TT and all PWB participants in the study group met their target weight-bearing status, with or without feedback, at Day 5. This treatment effect was preserved after 5 further days of training without the biofeedback. Among the TT subjects at Day 10, weight bearing was 21 ± 9% of body weight in the treatment group, significantly lower than in the control group (49 ± 26%). Among the PWB subjects at Day 10, weight bearing was 49 ± 9% of body weight in the treatment group, significantly lower than in the control group (64 ± 16%). The groups did not differ significantly on the secondary outcomes at any time. Biofeedback enhances the ability of patients to meet their prescribed amount of partial weight bearing.