Introduction In order to avoid pseudarthrosis in adolescent idiopathic (AIS) patients, it is recommended to bring additional bone graft or substitute. Modern rigid instrumentations have been shown to provide less pseudarthroses even without bone substitutes. The aim of our study was to determine the impact of using bones substitutes on fusion rates in adolescent idiopathic scoliosis patients undergoing PSF with sublaminar bands. Method AIS patients scheduled to undergo PSF with sublaminar bands were prospectively enrolled into this study and not given any bone substitutes (no-substitute group). Data were collected and analyzed in patients with at least two years of follow-up. Pseudarthrosis was diagnosed if at least one of the following was present: persistent back pain, hardware failure, loss of correction greater than 10 degrees. The results were compared to a control group who received bone substitutes for the same surgical procedure. Results Eighty-eight patients were included. For the whole cohort, the mean age was 14.8 years old and the mean follow-up was 30.9 months. For the `no-substitute' group (n = 44), the mean Cobb angle was 56 degrees pre-operatively, 20.1 degrees post-operatively, and 22 degrees at final follow-up. The fusion rate was not statistically different between the two groups (97.7% vs 95.5%, p = 0.56). At last follow-up, one pseudarthrosis occurred in the `no substitute' group and two in the control group. Discussion This is the first study to determine the impact of bone substitutes in AIS fusion using sublaminar bands. In our study, the use of local autologous bone graft alone resulted in a fusion rate of 97.7% despite the use of more flexible instrumentation. The high rate of fusion in AIS patients is more probably due to the healing potential of these young patients rather than to the type of instrumentation. Conclusion The use of additional bone graft or bone substitutes may not be mandatory when managing AIS.