Introduction. It has been postulated that a mild clubfoot does better than a severe clubfoot no matter what treatment course is taken. There have been previous efforts to classify clubfoot. For units worldwide that use the Ponseti Method of clubfoot management, the Pirani scoring system is widely used. This scoring system has previously been shown to predict the number of plasters required to gain correction. Our study aimed to investigate whether the Pirani score gave an indication of longer-term outcome using tibialis anterior tendon transfer as an endpoint. Methods. A prospectively collated database was used to identify all patients treated in the Ponseti clinic at the Royal Manchester Children's Hospital between 2002 and 2005 with idiopathic clubfoot who had not received any treatment prior to their referral. Rate of tibialis tendon transfer as well as the patient's presenting Pirani score were noted. Feet were grouped for analytical purposes into a mild clubfoot (Pirani score <4) and a severe clubfoot (Pirani score 4) category depending on initial examination. Clinic records were reviewed retrospectively to identify patients who were poorly compliant at wearing boots and bars and were categorised into having “good” or “bad” compliance with orthosis use. Results. 132 feet in 94 children were included in the study. 30 (23%) tibialis tendon transfers were performed at a mean of 4.2 years (range 2.3–5.5 years). Children with severe clubfoot had a significantly higher rate of tendon transfer compared with those with mild clubfoot (28% vs. 6%; p=0.0001). 81% of patients were classified as being “good” boot wearers. Tibialis tendon transfer rates in those who were poorly compliant with boot usage were significantly higher compared with those with good compliance (52% vs. 16%; p=0.0003). There was a significantly higher tendon transfer rate in those with severe disease and poor compliance compared with good compliance (69% vs. 20%; p=0.0002). There was no association between boot compliance and tendon transfer rates in those with mild disease. Conclusion. This study shows that late recurrences, requiring tibialis anterior tendon transfer, are associated with severity of disease at presentation and compliance with use of orthoses. Tendon transfer rates are higher for those with severe disease. We have confirmed previous reports that compliance with orthotic use is associated with recurrence. However, the novel findings regarding recurrence rates in mild clubfeet may have implications regarding usage of orthoses in the management of mild