Are current methods of partial weight-bearing instruction accurately translating to crutch-assisted gait?

Background/Aims:Partial weight-bearing protocols are commonly incorporated into hospital, clinical and field-based rehabilitation to enhance recovery, particularly in patients following cartilage surgeries. Overloading can affect healing time and the stability or integrity of the healing structure, however underloading can also be detrimental, as adequate weight bearing encourages the healing process—for example, osteoblastic stimulation. Therefore, accurate reproducibility of these protocols could be considered essential to the rehabilitation process. The aim of this study was to determine the accuracy with which weight-bearing protocols (20%, 50% or 80% of body weight) could be reproduced shortly after being taught.Methods:Thirty participants were taught three partial weight-bearing protocols (20%, 50% and 80% of body weight), using bathroom scales. Participants ability to reproduce their target load for each protocol was assessed statically using bathroom scales and dynamically with a force plate using a three-point elbow crutch-assisted gait. Participants were assessed 10 minutes after being taught. Errors between actual and target load during these trials was calculated.Findings:Accuracy assessed with scales was comparatively good for all target loads, however dynamic trials using the force plate showed an inverse relationship between all error measures and target loads (i.e. 20% > 50% > 80% body weight; all P<0.01). The peak error was double the intended load at 20% of body weight (95% CI: 11.9% body weight, 24.1% body weight). At 80% of body weight, the peak error was not significantly different from zero.Conclusions:The static method of instruction of partial weight-bearing protocols, using bathroom scales, does not seem to translate accurately to dynamic motion, and therefore affects adherence to medical instruction. Practitioners should be aware of the potential errors in reproducing these loads and the potential effect on rehabilitation. These results would suggest that practitioners should be cautious when using bathroom scales to teach partial weight-bearing protocols and not to rely on them to assess reproduction accuracy during gait.