Introduction. Traditional treatment of idiopathic flatfoot in the adult population include calcaneal neck lengthening or fusions. These surgical methods result in abnormal function with significant complication rates. Our prospective study aimed to quantify the functional and radiological outcome of a new technique for spring ligament reconstruction using a hamstring graft, calcaneal osteotomy and medial head of gastrocnemius recession if appropriate. Methods. 22 feet were identified from the senior authors flatfoot reconstructions over a 3 year period (Jan 2013 to Dec 2015). 9 feet underwent a spring ligament reconstruction. The control group were 13 feet treated with standard tibialis posterior reconstruction surgery. Follow up ranged from 8 to 49 months. Functional assessment comprised VAS heath and pain scales, EQ-5D and MOXFQ scores. Radiographic analysis was performed for standardised parameters. Results. Each group contained two bilateral procedures. The spring ligament patients had a mean age of 43, BMI of 29 and a male to female ratio of 4;1 There were no statistical differences between groups starting point functional scores or pre-operative radiological deformity. Post-operatively there was a statistically significant improvement of all domains and overall MOXFQ, EQ5d and VAS in the spring ligament patients. There was a statistically significant improvement in all radiological parameters with all patients being returned to normal. Functional scores were not significantly better than the control group [MOXFQ components, Control vs spring ligament group, Pain: 42 vs 45 (p=0.71), Walking: 50 vs 56 (p=0.43), Social: 35 vs 39 (p=0.72), EQ-5D: 0.64 vs 0.70 (p=0.72)]. Spring ligament reconstruction produced statistically better deformity correction for 4 of 5 measured radiological parameters (p< 0.05). Conclusion. Our new method of spring ligament reconstruction restores normal anatomy. In comparison to traditional procedures our method provides equivalent functional results and improved deformity correction