The effects of a hinge-post-strap type functional knee brace on patients with anterior cruciate ligament reconstruction

Abstract

This study compared the performance in isokinetic tests, static knee joint angle repositioning, running and jumping of subjects with ACL reconstruction under three conditions: (1) no brace, (2) functional Donjoy Legend brace, and (3) mechanical placebo knee brace. The mechanical placebo brace was made with similar materials and design as the functional knee brace except the mechanical hinges were removed. Furthermore, questions were asked using the subjective part of the Cincinnati rating scale and a custom designed questionnaire on the bracing habits and feelings towards using a functional knee brace. Thirty-one subjects with ACL reconstruction using the semitendinosus autograft, performed at least five months earlier, were recruited. Results showed that subjects ran and turned faster in the no brace condition than both bracing conditions (p<0.05). There was no significant difference in the jumping and isokinetic tests among the three conditions (p#62;0.05). For the knee joint angle repositioning test, subjects performed better in both bracing conditions than the no brace condition (p<0.05), but there was no difference between the two bracing conditions. These results suggested that the functional knee brace did not improve the motor performance of people with ACL reconstruction, after 5 months of operation. The use of a knee brace had actually caused a decline in the running and turning performance of these subjects. The only improvement observed with the brace was the static knee joint angle repositioning sense, but the improvement was not due to the mechanical hinges of the brace. It could be the cutaneous sensory stimulation from the brace that led to the improvement. Based on the above findings, the notion of functional ACL brace enhancing knee function after at least 5 months post-operation was not supported. The use of knee braces for subjects with ACL reconstruction needs further justification. For the subjective data, all subjects scored 60 points or more out of 100 in the Cincinnati subjective rating questionnaire. These results indicated that the subjects had rehabilitated quite well at the time of testing. Twenty-nine subjects(93.6%) felt that the functional knee brace could provide a sense of stability after ACL reconstruction. In conclusion, the present study has provided new information on the effects of functional knee brace on subjects with ACL reconstruction. The functional knee brace has a role to provide psychological support as well as static knee joint sense to subjects with ACL reconstruction. It could not improve the neuromuscular, running and jumping performances as evaluated in the present study, and it could even slow down the running and turning speed of these subjects.