Combined Subtalar and Naviculocuneiform Fusion for Treating Adult Acquired Flatfoot Deformity With Medial Arch Collapse at the Level of the Naviculocuneiform Joint

Abstract

Background: A challenge in treating acquired flatfoot deformities is the collapse of the medial arch at the level of the naviculocuneiform (NC) joint. Triple fusions, being a treatment option, may lead to problems such as increased foot stiffness. We thus established a method that combines subtalar (ST) fusion with NC fusion while preserving the Chopart joint. We analyzed the radiographic correction, fusion rate, and patient satisfaction with this procedure. Methods: 34 feet in 31 patients (female, 23; male, 8; age 67 [45-81] years) were treated with a ST and NC joint fusion. In 15 cases, a medial sliding-osteotomy was additionally necessary to fully correct hindfoot valgus. The following radiographic parameters were measured on weightbearing radiographs preoperatively and at 2 years: talo-first metatarsal angle, talocalcaneal angle, calcaneal pitch, talonavicular coverage angle and calcaneal offset. Fusion was radiologically confirmed. Results: All parameters, except the calcaneal pitch, showed a significant improvement. Fusion was observed after 1 year in all but 2 cases (94.1%). One nonunion each occurred at the ST and NC joint without needing any subsequent treatment. One patient developed avascular necrosis of the lateral talus with need for total ankle replacement after 1 year. All patients were satisfied with the obtained results. Conclusion: Our data suggest that a combined fusion of the ST and NC joint was effective and safe when treating adult acquired flatfoot with collapse of the medial arch at the level of the NC joint. Although the talonavicular joint was not fused, its subluxation was significantly reduced. Level of Evidence: Level IV, case series.

Contribution of First-Tarsometatarsal Joint Fusion to Deformity Correction in the Treatment of Adult-Acquired Flatfoot Deformity

“…Some authors have advocated for NC fusion in cases of substantial midfoot sag, but the indications for this procedure are not well defined. 24,29 Steiner et al examined the role of combined ST and NC fusion in restoring medial arch collapse in severe flatfoot deformity. The authors demonstrated in their cohort of patients a significant correction in Meary angle, talocalcaneal angle, TN coverage, and HMA, concluding that collapse at the medial arch can be restored with these procedures with good clinical and radiographic outcomes.…”

“…The authors demonstrated in their cohort of patients a significant correction in Meary angle, talocalcaneal angle, TN coverage, and HMA, concluding that collapse at the medial arch can be restored with these procedures with good clinical and radiographic outcomes. 29 However, the necessity of correcting deformity at the NC joint has not been established.…”

Talus morphology differs between flatfeet and controls, but its variety has no influence on extent of surgical deformity correction

“…Other exclusion criteria were additional bony procedures on the hindfoot [i.e. subtalar arthrodesis (n = 37) or medial sliding calcaneus osteotomy (n = 9)] or the medial column (Cotton osteotomy, arthrodesis of the 1st tarsometatarsal joint [15,16] or the navicular-cuneiform joint [17,18] (n, in total = 18)), lack of preoperative MRI or CT of the hindfoot (n = 10), and lack of pre-and postoperative complete conventional radiographs (weight-bearing lateral and dorsoplantar views) (n = 2) with a minimum follow-up of 3 months.…”

Consensus on Indications for Isolated Subtalar Joint Fusion and Naviculocuneiform Fusions for Progressive Collapsing Foot Deformity

“…However, the concept of using an NC fusion instead TN fusion was reported to be successful in correcting and stabilizing the forefoot. 34,35 With the hypothesis that attenuation of the medial supporting structures of the foot results in the progression of the PCFD, Miller 28 was the first to propose correction of the medial alignment of the foot by fusion of the medial column, specifically, a fusion of the NC and first TMT joints. In addition to the medial column fusion, he performed an advancement of the PTT complex as an osteoperiosteal flap.…”

“…2,13 Even though prior literature has reported important nonunion rates of NC joint fusions, 20,28,34 using this surgical technique, union of both joints was found in 32 of 34 cases; a nonunion occurred in only 1 case at the ST joint and in 1 case at the NC fusion site, but the patient remained asymptomatic. 35 The low nonunion rate could potentially be explained by a protective effect of the ST fusion stability to the fusion site at the NC joint, possibly decreasing the mechanical overload in this joint, even with early weightbearing as tolerated being allowed immediately postoperatively. In 15 cases (44%), an additional medial sliding osteotomy of the calcaneus was performed to achieve the required correction of hindfoot alignment, and in 5 cases (14.7%), an FDL tendon transfer was done.…”