Subtalar arthrodesis with flexor digitorum longus transfer and spring ligament repair for treatment of posterior tibial tendon insufficiency

The surgical treatment of flexible pes planovalgus deformities resulting fr om Stage 2 posterior tibial tendon insufficiency is controversial and many techniques have been proposed, We retrospectively reviewed the results of s ubtalar arthrodesis combined with spring ligament repair/reefing and flexor digitorum longus (FDL) transfer to the navicular. There were sixteen patie nts (seventeen feet) with an average follow-up of 27 months (9-52), All def ormities were passively correctable. The average age was 56 yrs (39-78). All patients had failed conservative ma nagement, 88% had previously been treated with orthotics, and 53% had later al pain from subfibular impingement. Two patients were noted to have degene rative changes of the subtalar joint. Successful subtalar joint fusion occurred in all patients with an average t ime to radiographic union of 10.1 weeks (5-24). The average AOFAS hindfoot score and Maryland foot score postoperatively was 82 and 86 respectively, S tanding radiographic analysis demonstrated an average improvement in the AP talo-1st metatarsal angle of 6 degrees (24 degrees preoperative, 18 degree s postoperative), The talonavicular coverage angle improved an average of 1 7 degrees (34 degrees preoperative, 17 degrees postoperative), The lateral talo-1st metatarsal angle improved an average of 10 degrees (18 degrees pre operative, 8 degrees postoperative), The lateral talocalcaneal angle decrea sed an average of 21o (55 degrees preoperative, 34 degrees postoperative), The distance of the medial cuneiform to the floor on the lateral radiograph averaged 12mm preoperatively and 18mm postoperatively (avg, improvement 6m m). The combination of the flexor digitorum longus tendon transfer and spring l igament repair with subtalar arthrodesis is an effective and reliable proce dure which provides excellent correction of hindfoot valgus as well as:fore foot abduction and restoration of the height of the longitudinal arch, Thes e results compare favorably with flexor transfer combined with either calca neal osteotomy or lateral column lengthening.