Effect of Medial Ligament Reconstruction in Flatfoot Deformity: How It Affects the Soft Tissue Improvement and Radiological Outcome of the Surgery?

CATEGORY: Ankle; Hindfoot; Sports INTRODUCTION/PURPOSE: Surgical treatment of adult flatfoot deformity has traditionally be driven by tendon transfers and osteotomy. In acquired deformity, injury to the spring ligament and superficial deltoid ligament is common. The procedures mentioned previously do nothing to restore the function of the medial ligament complex. Studies have shown that reconstruction of the medial ligament complex, and thus the medial talonavicular joint, has benefit to patient outcomes. The question still remains of how much correction the medial ligament reconstruction confers on its own. The purpose of this study is to compare isolated medial ligament reconstruction procedures to other flat foot correcting procedures in the treatment of acquired flat foot deformity. METHODS: 18 patients were identified that underwent procedure for flatfoot deformity. Of these patients there were 7 patients that underwent isolated medial ligament complex reconstruction and 11 patients that underwent non-tendon transfer procedure for correction of flat foot deformity. Imaging was performed on patient's weight bearing (WB) and non-weight bearing (NWB) before and after surgery. Measurements included Angles: calcaneal pitch, talo-1st metatarsal, talocalcaneal, talar declination, calcaneal 1st metatarsal and Distances: talar height, navicular height, 1st cuneiform height, cuboid height, and 1st to 5th metatarsal distance in lateral X-ray, and Angles: talonavicular coverage, talar 1st metatarsal, talar 2nd metatarsal and Distances: talonavicular uncoverage distance in AP. The differences in measurement between the pre-op and post-op non-weight bearing are considered as bony correction effect while differences between pre-op and post-op weight bearingare considered as soft tissue correction RESULTS: For non-weight bearing; medial ligament reconstruction impact was seen on calcaneal pitch (19 to 35 degrees, p=0.007), 1st cuneiform height (21 to 28mm, p=0.016), talonavicular coverage (6 to 3 degrees, p=0.026), and Talar 1st metatarsal angle (14 to 7 degrees, p=0.008). Other corrections had an impact on calcaneal pitch (15 to 24 degrees, p=0.006), Talo-1st metatarsal angle (11 to 6 degrees, p=0.019), Calcaneal 1st metatarsal (139 to 129 degrees, p=0.044), Talar height (31 to 42mm, p=0.001), navicular height (24 to 34mm, p=0.002), and 1st cuneiform height (18 to 22mm, p=0.016). For weight bearing; reconstruction impact was seen on talocalcaneal angle (36 to 44 degrees, p=0.011), 1st-5thmetatarsal distance (12 to 18mm, p=0.047), and hindfoot moment arm (16 to 6mm, p=0.031). Other corrections had an impact on talar height (34 to 40mm, p=0.028), navicular height (26 to 30mm, p=0.031), cuboid height (p=0.021), and hindfoot alignment angle (17 to 7 degrees, p=0.003). CONCLUSION: When compared to procedures that only address bony changes in the foot, it is clear from this study that medial ligament repair plays a different, but significant, role in correction of flat foot deformity. Interestingly, the non-weight bearing and weight bearing results show that medial ligament reconstruction affects different aspects of the correction in these two distinct phases. This study serves to suggest that medial ligament reconstruction has a role in the correction of flat foot deformity that is not completely addressed in the more common procedures performed.