Another tendon transfer method was described by Cobb and popularised in the southern UK and some other circles by Helal. The tibialis anterior tendon was split, passed through the medial cuneiform or the tibialis posterior insertion, then through the tibialis posterior sheath and attached to the tibialis posterior stump proximally. This gave a large, strong reconstruction which seemed more able to restore the arch.
Only two substantial series have been published. Knupp and Hintermann (2007) reported 22 patients followed up for a mean of 24 (12-46) months. They did not report the disease stage as such but comment that all patients had "supple forefoot supination deformities" in a way that imples they were probably Truro stage 2a or 2b. The AOFAS ankle-hindfoot score improved from a mean of 53(40-68) pre-operatively to 88(78-94). Eleven also had a medial displacement calcaneal osteotomy, 3 a lengthening ostoeotmy, 17 repair of the deltoid and 3 of the spring ligament. There was no weakness of the tibialis anterior at follow-up. Nineteen patients could wear shoes without modifications or insoles. One patient had a wound healing problem, one a nerve injury and one was revised to a triple fusion for continuing pain.
Parsons (2010) reported 32 patients with stage 2a AAFF treated with a Cobb transfer and a medial displacement calcaneal osteotomy. Follow-up was 3-7.2yr. Two patients had repair of the spring ligament. A split tibialis anterior grat was passed hrough a drill hole in the navicular from dorsal to plantar and sutured to the dorsum of the naviculocuneiform joint as a check-rein. Mean AOFAS score increased from 52.2-89/100. 29 paients were abole to do a single-foot tiptoe at fllow-up. All patients retained grade 5 power of the remaining tibialis anterior. There was one infection and one nerve injury. All patients continued to wear at least comfort insoles.
Giorgini (2010) described a combination of the Kidner and Cobb procedures in 21 patients with stage 2 adult acquired flatfoot, as well as 19 children with hypermobile flatfeet. An unspecified number of additional procedures were also performed. 19/21 had no pain, problems with shoe wear or activity limitations at a mean follow-up of 4.6y.
These results are comparable to those reported for medial displacement calcaneal osteotomy with FDL or FHL transfer. A RCT comparing these techniques would be appropriate although recruitment of enough patients would probably require a multicentre trial.