Level IV, prospective case series.

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.

In many cases of acquired flatfoot deformity,

Category: Midfoot/Forefoot Introduction/Purpose: A conflicting problem in treating acquired flatfoot deformities is the break-down of the arch at the naviculocuneiform (NC) joints. After having encountered problems with extended triple fusion, in particular increased stiffness of the foot, we established a rational to combine subtalar (ST) fusion with NC I-III fusion while preserving the talonavicular (TN) and calcaneo-cuboidal (CC) joint. Our hypothesis was that the break-down of the arch at the NC joint can be specifically addressed while sparing the Chopart Joint (TN and CC joint). This, in turn, will allow the patient to accommodate better to the ground while walking. The aim of the study was to analyze the radiographic correction and fusion rate, and to determine patient’s satisfaction with this procedure. Methods: Between 2009 and 2015, a consecutive series of 34 feet in 31 patients (female, 23; male, 8; age 67 [45-81] years) were treated by combining a fusion of the subtalar joint with a NC fusion. Both joints were exposed through a medial approach. Two 7.5mm-screws were used for ST fusion, and two 5.5mm-screws were used for NC fusion. In addition an anatomically contoured plate was used as a medio-plantar tension bending support of the NC joint. In 15 patients, an additional medial sliding-osteotomy was done to fully correct valgus misalignment of the hindfoot. The following measures were taken on standard weight-bearing radiographs including hindfoot alignment view preoperatively and at 2 years: the talus-first metatarsal angle, the talocalcaneal angle, the calcaneal pitch, the talonavicular coverage angle, the talus-first metatarsal angle, and calcaneal offset. Bony fusion was confirmed on plain radiographs. If no trabeculation was visible, a CT scan was performed. Results: All radiographic parameters, except the calcaneal pitch, showed a statistically significant improvement (Table 1). Solid fusion at the arthrodesis site was observed between 8 and 12 weeks in all but 2 cases (94.1%). One nonunion occurred at the ST joint and one at the NC joint. No interventions were necessary as both cases were asymptomatic. One patient developed an avascular necrosis of the lateral talus with need for a total ankle replacement after one year. All patients were satisfied with the results of this procedure and stated that they would undergo the surgery again. All patients were able to wear normal shoes without insoles. Conclusion: Our results show that a combined fusion of the subtalar and NC joint is an effective and safe technique in treating the adult acquired flatfoot with collapse of the medial arch at the level of the NC joint. The deformity was corrected in all three planes. Even though the TN joint was not fused, its subluxation was significantly reduced. Although our radiographic results are promising, a clinical follow-up study is necessary to quantify the clinical benefit of this procedure.