Radiographic Evaluation of Adult Acquired Flatfoot Correction with Augmented Spring Ligament Repair

CATEGORY: Flatfoot reconstruction INTRODUCTION/PURPOSE: Adult acquired flatfoot often results from posterior tibial tendon dysfunction followed by attenuation of the ligamentous support of the medial longitudinal arch of the foot. The spring ligament is the strongest ligamentous support for the talonavicular joint making it a viable target for flatfoot reconstruction procedures. There are concerns that direct repair of the spring ligament complex could result in failure as the already attenuated tissues of the ligament stretch out with mobilization and weight bearing. Suture tape augmentation of ligament repairs has shown greater loads to failure in biomechanical testing; however, there is a paucity of data surrounding clinical and radiographic outcomes of flatfoot reconstruction with augmented spring ligament repair. METHODS: A retrospective review was performed of patients who underwent flatfoot reconstruction including spring ligament repair with suture tape augmentation between July 2014 and August 2017. Weight bearing radiographs were obtained for all patients both pre-operatively and at their last available follow-up. All radiographs were assessed by two surgeons for validated radiographic parameters including AP talocalcaneal angle, AP talo-first metatarsal angle, AP talar uncoverage, lateral talocalcaneal angle, lateral talo-first metatarsal (Meary) angle, lateral medial cuneiform-fifth metatarsal height, and lateral calcaneal pitch. Paired sample T-tests were used to compare pre-operative and post-operative radiographic measurements to assess for correction of these parameters. RESULTS: 57 patients met inclusion criteria. The average time to final radiographic evaluation was 47 weeks (10 to 200 weeks). All radiographic parameters assessed showed significant correction when compared to pre-operative measurements. The average correction for each parameter included 6.02 degrees for AP talocalcaneal angle (p<0.001), 10.96 degrees for AP talo-first metatarsal angle (p<0.001), 12.65% for AP talar uncoverage percentage (p<0.001), 4.27 degrees for lateral talocalcaneal angle (p<0.001), 11.35 degrees for lateral talo-first metatarsal (Meary) angle (p<0.001), 8.31 mm for lateral medial cuneiform-fifth metatarsal height (p<0.001), and 2.91 degrees for lateral calcaneal pitch (p<0.001). Post-operative complications occurred in 5 patients. CONCLUSION: Reconstruction of adult acquired flatfoot with spring ligament repair using suture tape augmentation is a safe procedure that resulted in significant weight bearing radiographic correction at an average of 47 weeks follow-up.