Background: Hallux valgus (HV) is a triplanar deformity of the first ray including pronation of the first metatarsal with subluxation of the sesamoids. The purpose of this study was to investigate if a first tarsometatarsal fusion (modified Lapidus technique), without preoperative knowledge of pronation measured on weightbearing computed tomographic (CT) scans, changed pronation of the first metatarsal and determine if reduction of the sesamoids was correlated with changes in first metatarsal pronation. Methods: Thirty-one feet in 31 patients with HV who underwent a modified Lapidus procedure had preoperative and at least 5-month postoperative weightbearing CT scans and radiographs. Differences in preoperative and postoperative pronation of the first metatarsal using a 3-dimensional computer-aided design, HV angle, and intermetatarsal angle (IMA) were calculated using Wilcoxon signed-rank tests. After dividing patients into groups based on sesamoid station, Kruskal-Wallis H tests were used to compare first metatarsal pronation between the groups. Results: The mean preoperative and postoperative pronation of the first metatarsal was 29.0 degrees (range 15.8-51.1, SD 8.7) and 20.2 degrees (range 10.4-32.6, SD 5.4), respectively, which was a mean change in pronation of the first ray of −8.8 degrees ( P < .001). There was no difference in pronation of the first ray when stratified by postoperative sesamoid position ( P > .250). The average preoperative and postoperative IMA was 16.7 degrees (SD 3.2) and 8.8 degrees (SD 2.8), which demonstrated a significant change ( P < .001). Conclusions: The modified Lapidus procedure was an effective tool to change pronation of the first ray. Reduction of the sesamoids was not associated with postoperative first metatarsal pronation. Level of Evidence: Level IV, case series.

Background: The Salto Talaris is a fixed-bearing implant first approved in the US in 2006. While early surgical outcomes have been promising, mid- to long-term survivorship data are limited. The aim of this study was to present the survivorship and causes of failure of the Salto Talaris implant, with functional and radiographic outcomes. Methods: Eighty-seven prospectively followed patients who underwent total ankle arthroplasty with the Salto Talaris between 2007 and 2015 at our institution were retrospectively identified. Of these, 82 patients (85 ankles) had a minimum follow-up of 5 (mean, 7.1; range, 5-12) years. The mean age was 63.5 (range, 42-82) years and the mean body mass index was 28.1 (range, 17.9-41.2) kg/m2. Survivorship was determined by incidence of revision, defined as removal/exchange of a metal component. Preoperative, immediate, and minimum 5-year postoperative AP and lateral weightbearing radiographs were reviewed; tibiotalar alignment (TTA) and the medial distal tibial angle (MDTA) were measured to assess coronal talar and tibial alignment, respectively. The sagittal tibial angle (STA) was measured; the talar inclination angle (TIA) was measured to evaluate for radiographic subsidence of the implant, defined as a change in TIA of 5 degrees or more from the immediately to the latest postoperative lateral radiograph. The locations of periprosthetic cysts were documented. Preoperative and minimum 5-year postoperative Foot and Ankle Outcome Score (FAOS) subscales were compared. Results: Survivorship was 97.6% with 2 revisions. One patient underwent tibial and talar component revision for varus malalignment of the ankle; another underwent talar component revision for aseptic loosening and subsidence. The rate of other reoperations was 21.2% ( n = 18), with the main reoperation being exostectomy with debridement for ankle impingement ( n = 12). At final follow-up, the average TTA improved 4.4 (± 3.8) degrees, the average MDTA improved 3.4 (± 2.6) degrees, and the average STA improved 5.3 (± 4.5) degrees. Periprosthetic cysts were observed in 18 patients, and there was no radiographic subsidence. All FAOS subscales demonstrated significant improvement at final follow-up. Conclusions: We found the Salto Talaris implant to be durable, consistent with previous studies of shorter follow-up lengths. We observed significant improvement in radiographic alignment as well as patient-reported clinical outcomes at a minimum 5-year follow-up. Level of Evidence: Level IV, retrospective case series.

Background: Semiautomatic 3-dimensional (3D) biometric weightbearing computed tomography (WBCT) tools have been shown to adequately demonstrate the relationship between the center of the ankle joint and the tripod of the foot. The measurement of the foot and ankle offset (FAO) represents an optimized biomechanical assessment of foot alignment. The objective of this study was to evaluate the correlation between FAO and traditional adult acquired flatfoot deformity (AAFD) markers, measured in different planes. We hypothesized that the FAO would significantly correlate with other radiographic markers of pronounced AAFD. Methods: In this retrospective comparative study, we included 113 patients with stage II AAFD, 43 men and 70 women, mean age of 53.5 (range, 20-86) years. 3D coordinates (x, y, and z planes) of the foot tripod (most plantar voxel of the first and fifth metatarsal heads, and calcaneal tuberosity) and the center of the ankle joint (most proximal and central voxel of the talar dome) were assessed by 2 blinded and independent fellowship-trained orthopedic foot and ankle surgeons. The FAO was automatically calculated using the 3D coordinates by dedicated software. Multiple WBCT parameters related to the severity of the deformity in the coronal, sagittal, and transverse planes were manually measured. Results: We found overall good to excellent intra- (range, 0.75-0.99) and interobserver (range, 0.73-0.99) reliability for manual AAFD measurements. FAO semiautomatic measurements demonstrated excellent intra- (0.99) and interobserver (0.99) reliabilities. Hindfoot moment arm (HMA) ( P < .00001), subtalar horizontal angle ( P < .00001), talonavicular coverage angle ( P = .00004), and forefoot arch angle ( P = .0001) were the only variables found to significantly influence and correlate with FAO measurements, with an R2 value of 0.79. An HMA value of 19.8 mm was found to be a strong threshold predictor of increased values of FAO, with mean values of FAO of 6.5 when the HMA was lower than 19.8 mm and 14.6 when the HMA was equal to or higher than 19.8 mm. Conclusion: We found that 3D WBCT semiautomatic measurements of FAO significantly correlated with some traditional markers of pronounced AAFD. Measurements of FAO were also found to be slightly more reliable than the manual measurements. The FAO offers a simple and more complete biomechanical and multiplanar assessment of the AAFD, representing in a single measurement the 3D components of the deformity. Level of Evidence: Level III, retrospective comparative study.

Background: Residual supination of the midfoot during reconstruction of the stage II adult-acquired flatfoot deformity (AAFD) is often addressed with a medial cuneiform (Cotton) osteotomy after adequate correction of the hindfoot valgus deformity. The purpose of this study was to determine if there was a correlation between postoperative alignment of the medial cuneiform and patient-reported outcomes. Methods: Sixty-three feet in 61 patients with stage II AAFD who underwent a Cotton osteotomy as part of a flatfoot reconstruction were included in the study. Radiographic angles were measured on weightbearing lateral radiographs at a minimum of 40 weeks postoperatively. Pearson’s correlation analysis was used to determine if there was an association between postoperative radiographic angles and Foot and Ankle Outcome Score (FAOS) at a minimum of 24 months postoperatively. Patients were also divided into mild plantarflexion (cuneiform articular angle [CAA] ≥–2 degrees) and moderate plantarflexion (CAA <–2 degrees) groups to evaluate for differences in clinical outcomes. Results: Postoperative CAA was significantly positively correlated with the postoperative FAOS symptoms ( r = .27, P = .03), daily activities ( r = .29, P = .02), sports activities ( r = .26, P = .048), and quality of life ( r = .28, P = .02) subscales. Patients in the mild plantarflexion group had statistically and clinically better outcomes compared with the moderate plantarflexion group in the FAOS symptoms ( P = .04), daily activities ( P = .04), and sports activities ( P = .01) subscales. Conclusions: Our study suggests that the surgeon should avoid excessive plantarflexion of the medial cuneiform and use the Cotton osteotomy judiciously as part of a flatfoot reconstruction for stage II AAFD. Level of Evidence: Level III, comparative series.

Background: Assessment of operative correction of adult-acquired flatfoot deformity (AAFD) has been traditionally performed by clinical evaluation and conventional radiographic imaging. Previously, a 3-dimensional biometric weightbearing computed tomography (WBCT) tool, the foot ankle offset (FAO), has been developed and validated in assessing hindfoot alignment. The purpose of this study was to investigate the role of FAO in evaluating operative deformity correction in AAFD. Methods: In this prospective comparative study, 19 adult patients (20 feet) with stage II (flexible) flatfoot deformity underwent preoperative and postoperative standing WBCT examination at mean 19 months (range, 6-24) after surgery. Three-dimensional coordinates of the foot tripod and center of the ankle joint were acquired by 2 independent and blinded observers. These coordinates were used to calculate the FAO using dedicated software, and subsequently compared pre- and postoperatively. The FAO is a previously validated biometric measurement that represents centering of the foot tripod as well as hindfoot alignment, with a normal mean FAO of 2.3% ± 2.9%. In addition, Patient Reported Outcomes Measurement Information System (PROMIS) clinical outcomes scores were compared pre- and postoperatively with a mean follow-up of 22.6 months (range, 14-37). Results: There was significant correction of flatfoot deformity from a mean preoperative FAO of 9.8% to a mean postoperative value of 1.3% ( P < .001). Additionally, there was statistically significant improvement in all PROMIS domains ( P < .05), except depression, at an average follow-up of 22.6 months. Spring ligament reconstruction was the only procedure associated with a significant correction in FAO ( P = .0064). Conclusion: The FAO was a reliable and sensitive tool that was used to evaluate preoperative deformity as well as postoperative correction, with patients demonstrating both significant improvement in FAO as well as patient-reported outcomes. These findings demonstrate the role for biometric 3-dimensional WBCT imaging in assessing operative correction after flatfoot reconstruction, as well as the potential role for operative planning to address preoperative deformity. Level of Evidence: Level II, prospective comparative study.