Walking, orthoses and physical effort in a Swedish population with arthrogryposis

PURPOSE Excessive movements during walking have been observed by gait analysis in children with arthrogryposis (AMC) using orthoses compared to children using only shoes. The aim of this study was to evaluate energy expenditure and functional exercise capacity in children with AMC. METHODS Twenty-four children with AMC and 25 typically developing (TD) children underwent oxygen measurement and the 6-minute walk test (6MWT). Children were divided into AMC1 using knee-ankle-foot orthoses with locked knee joints (KAFO-LK); AMC2 KAFOs with open knee joints (KAFO-O) or ankle-foot orthoses (AFO); and AMC3 using shoes. RESULTS The net non-dimensional oxygen cost (NNcost) was lower in TD (0.308) than in AMC2 (0.455, n = 10) (p = 0.002). There were no differences in the net non-dimensional consumption (NNconsumption) or normalised walking velocity. The lowest NNconsumption (0.082), NNcost (0.385) and normalised walking velocity (0.214) were found in AMC1 (n = 3), but no statistical calculation was performed. In the 6MWT, both AMC2 (402.7, n = 11) and AMC3 (476.8, n = 10) walked shorter distances (m) than TD (565.1) (p < 0.001 and p = 0.043, respectively). AMC2 (0.435) had lower normalised walking velocity than TD (0.564) (p < 0.001). CONCLUSIONS Children with AMC using open KAFOs or AFOs (AMC2) had higher energy effort represented by significantly higher NNcost than TD, whereas AMC children requiring only shoes (AMC3) did not differ significantly from TD. To maintain the NNconsumption at an acceptable level, children using locked KAFOs (AMC1) slowed down their walking velocity. Compared to TD, the exercise capacity was lower in children with AMC using open KAFOs or AFOs and shoes, represented by lower walking velocity and shorter distance walked during the 6MWT.