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Category: Ankle Arthritis; Ankle Introduction/Purpose: Fourth generation total ankle arthroplasty (TAA) implants minimize tibial resection and utilize small pegs or posts for fixation. The components are designed to facilitate osseous integration. However, a number of studies have identified concerning rates of lucencies around the tibial components of all newer generation implants. In this study, we evaluated a consecutive series of patients receiving a fourth generation TAA prosthesis to describe the incidence and characteristics of tibial component lucencies at minimum one year follow-up. Of these patients, we aimed to identify the rate of revision surgery. Secondary aims included identifying any difference in patient factors between patients with global lucencies and a cohort of patients without lucencies. Methods: A prospectively-collected TAA registry was queried to identify eligible patients. All patients greater than 18 years old who underwent primary TAA with a Cadence, Infinity, Infinity Adaptis, or Vantage prosthesis through January 2021 were identified. Each surgery was performed by one of six fellowship-trained orthopedic foot and ankle surgeons. For radiographic analyses, lucency was defined as a radiolucent line adjacent to the tibial tray of at least 1 mm in thickness, comprising at least 50% of the zone (Figure). Poorly-defined lucency around the tibial component in all four tibial zones, as agreed upon by two independent reviewers, was considered “global lucency.” Intraoperative, one year, and two year postoperative radiographs were assessed for periprosthetic lucencies. Pre- and postoperative coronal tibiotalar alignment was recorded. Additional data collected included age, sex, BMI, diagnosis, presence of diabetes, smoking status, presence of ipsilateral hindfoot fusion, pre- and postoperative PROMIS scores, and reoperation and complication data. Results: 616 ankles were analyzed: 274 Vantage (44.4%), 253 Infinity (41.1%), 52 Cadence (8.4%), and 37 Infinity Adaptis (6.0%). Mean radiographic follow-up was 27±20 months. There were 28 revisions (4.5%), 21 (3.4%) for symptomatic tibial component loosening. 36 patients (5.8%) had global tibial lucency at one year. Of these, 15 (42%) were eventually revised and the remaining 21 (58%) were doing well clinically at final follow-up. When comparing patients with global lucency at 1 year and revision for loosening (42 patients, 6.8%) with the remaining patients, there were no significant differences in any of the factors assessed (Table). PROMIS pain interference scores were higher at 2 years in the loosening group (p = 0.03). Intraoperative lucencies were not predictive of global lucency or revision for loosening. Conclusion: Aseptic loosening is the most common mode of failure of TAA, and has been reported with all of the low-profile fourth generation implants. We found a 6.8% incidence of tibial loosening (global radiographic lucency at 1 year or revision for tibial loosening). We were unable to identify any patient factors associated with loosening. Although 50% of these patients did not require revision and were doing well clinically at early follow-up, tibial loosening was associated with higher PROMIS pain interference scores at 2 years. Further research will be required to determine how patients with tibial loosening fare over longer-term follow-up.

Category: Hindfoot; Other Introduction/Purpose: In addition to peri-talar subluxation of the foot, previous studies have demonstrated that the talus is more internally rotated with respect to the trans-malleolar axis of the ankle in PCFD patients compared with normal patients. However, no studies have investigated the change in rotation of the talus in PCFD postoperatively and its association with outcomes. The primary aim of this study was to investigate the preoperative to postoperative change in rotation of the talus following reconstruction of the flexible PCFD. Secondary aims were to determine whether changes in rotation of the talus were associated with radiographic measurements of PCFD or specific reconstructive procedures and whether postoperative talar rotation was associated with two-year patient-reported outcome scores. Methods: Thirty-four consecutive patients over the age of 18 years old who underwent reconstruction of a flexible PCFD with preoperative and at least 5-month postoperative weightbearing CT (WBCT) scans and plain radiographs and had preoperative and at least two-year postoperative PROMIS scores were included in the study. Patients were excluded if they underwent a talonavicular fusion. Talar axial rotation was the angle between the transmalleolar axis and talar axis on preoperative and postoperative WBCT scans as previously described by Kim et al (2023) with smaller angles representing more internal rotation. Hindfoot moment arm, Meary’s angle, and talonavicular angle were measured on plain radiographs. Due to small sample sizes, descriptive statistics are reported as median and interquartile ranges (IQRs). Wilcoxon signed rank and Mann Whiney U tests were used to investigate differences between groups. Spearman correlation coefficients were employed to detect associations between variables and reported using 95% confidence intervals (95% CIs). Results: Median preoperative and postoperative talar axial rotation were 39.9° (IQR 36.7°, 45.3°) and 49.7° (IQR 45.9°, 57.3°, P < 0.001), respectively. The talus externally rotated by a median of 8.3° (IQR 4.1°, 13.1°) following surgery. The preoperative to postoperative change in talar rotation was not associated with changes in any plain radiographic parameter (Table 1). Increasing external rotation of the talus was associated with an increase in postoperative PROMIS Pain Intensity (rho=0.38, 95% CI 0.00, 0.67) with similar trends in the PROMIS Physical Function (rho=-0.22, 95% CI -0.55, 0.18) and Pain Interference (rho=0.19, 95% CI -0.21, 0.53) domains (Figure 1). Lateral column lengthening and subtalar fusion procedures were not associated with changes in talar rotation (both P > 0.10). Conclusion: Reconstruction of the flexible PCFD distal to the talus results in external rotation of the talus within the ankle mortise. Talar rotation was not associated with common measures of deformity or specific procedures. Kim et al. found that control patients had approximately 40°-60° of talar axial rotation, which is similar to the corrected position of the talus in our study. However, increasing talar external rotation resulted in worse postoperative PROMIS Pain Intensity scores with a similar trend seen in other PROMIS domains and raises the possibility of overcorrecting the internal rotational deformity of the talus in flexible PCFD.

Category: Hindfoot; Other Introduction/Purpose: As progressive collapsing foot deformity (PCFD) advances, narrowing between the lateral talar process and calcaneus at the angle of Gissane often occurs. This signifies more advanced peri-talar subluxation and may result in sinus tarsi impingement. However, the clinical significance of narrowing at the angle of Gissane and its effect on patient-reported outcomes following a flatfoot reconstruction is unknown. The primary aim of this study was to investigate if there was a relationship between preoperative talocalcaneal distance between the lateral talar process and calcaneus at the angle of Gissane and two-year postoperative outcomes in patients with flexible PCFD who underwent a reconstruction of their deformity. A secondary aim was to compare this cohort of patients to those who underwent a subtalar arthrodesis. Methods: Seventy-six consecutive patients >18 years old who underwent reconstruction of a flexible PCFD with (fusion cohort, n=40) or without (non-fusion cohort, n=36) a subtalar arthrodesis, had preoperative weightbearing CT (WBCT) scans, and had preoperative and ≥two-year postoperative PROMIS scores were included. Patient were excluded if they underwent a talonavicular fusion. Patients underwent a subtalar fusion if their chief complaint was lateral sinus tarsi pain. The talocalcaneal distance was measured on preoperative WBCT scans as the closest distance between the lateral process of the talus and the superior aspect of the calcaneus (Jeng et al 2018). Spearman correlation coefficients and multivariable regression analyses controlling for subtalar fusion were calculated between preoperative talocalcaneal distance and postoperative PROMIS scores. Due to the small sample sizes, descriptive statistics were reported as median and interquartile range (IQR), and differences between the non-fusion and fusion cohorts were determined using Mann Whitney U tests. Results: The median preoperative talocalcaneal distance for the non-fusion and fusion cohorts were 1.2 mm (IQR 0.75 mm, 1.7 mm) and 0.6 mm (IQR 0.1 mm, 1.1 mm, P=0.007), respectively. For the non-fusion cohort, there was no correlation between preoperative talocalcaneal distance and two-year postoperative PROMIS Physical Function (rho=0.198, P=0.891), Pain Interference (rho=-0.0136, P=0.891), and Pain Intensity (rho=-0.038, P=0.923). Similarly, there was no correlation between preoperative talocalcaneal distance and two-year postoperative PROMIS scores for the fusion cohort (all P>0.80). At two-years postoperatively, there was no difference in PROMIS scores between the non-fusion and fusion cohorts (all P>0.10) (Table 1). When controlling for talocalcaneal distance, there was no difference in postoperative PROMIS scores between the fusion and non-fusion cohorts (all P>0.30) (Figure 1). Conclusion: In PCFD patients undergoing a flatfoot reconstruction, there was no correlation between preoperative talocalcaneal distance and two-year postoperative patient-reported outcomes. Additionally, there was no difference in outcomes between patients who underwent a subtalar arthrodesis compared with patients who underwent a reconstruction even when controlling for talocalcaneal distance. Our results suggest that preoperative talocalcaneal distance is not an indication for subtalar arthrodesis. Additionally, patients indicated for a subtalar fusion for correction of their flexible PCFD deformity do not have worse outcomes than patients who did not undergo a subtalar arthrodesis regardless of preoperative talocalcaneal distance.

Category: Bunion; Midfoot/Forefoot Introduction/Purpose: Hallux valgus(HV) is a triplanar deformity that includes the pronation of the first ray. Although there is little data regarding the effect of pronation on clinical outcomes, the rotational component of HV may play an important role. One study suggested that the modified Lapidus technique effectively decreased the pronation of the first ray. However, there is no evidence for alternative procedures such as minimally invasive(MIS) bunionectomy. This study sought to assess if MIS bunionectomy can effectively correct the first ray's pronation and determine the correlation with improved PROMIS scores. In addition, the association between postoperative first-ray pronation and the sesamoid station was investigated. We hypothesized a significant decrease in first-ray pronation after MIS bunionectomy, which would be associated with improved PROMIS scores. Methods: Sixty-three consecutive patients who underwent MIS bunionectomy with available pre- and at least 5-month postoperative WBCT-scans were included. Pre- and postoperative measurements of HV deformity, including the intermetatarsal angle(IMA) and hallux valgus angle (HVA) on plain radiographs, and triplanar pronation angle (TAP – a measure of first ray pronation) and sesamoid station from WBCTs, were performed as previously described. The TAP was referenced to the dorsal aspect of the second metatarsal base. Pre- and 1-year postoperative PROMIS scores were reviewed. Sample t-tests were used to compare pre- and postoperative values. The Kruskal-Wallis test assessed statistical differences between postoperative sesamoid station groups regarding postoperative TAP or IMA. Spearman rank (rho) was used to assess correlations between pre- to postoperative change in TAP with PROMIS scores in the physical function (PF), pain interference (PIF), and pain intensity (PI) domains. Scatterplots were simultaneously presented to visualize potential trends between TAP and PROMIS scores. Results: The mean TAP significantly decreased by 8.21º(95%CI -9.62,-6.8) after MIS bunionectomy (p< 0.05). Mean(SD) pre- and postoperative TAP values were 31.57º(8.3) and 23.36º(7.6), respectively. Similarly, mean HVA and IMA values decreased by 21.98º and 11.41º, respectively. Mean preoperative sesamoid station was 1.84, which decreased to 0.95 after surgery. Forty-four patients reduced their sesamoid position by one station. There was a statistically significant difference in TAP between postoperative sesamoid station groups (p=0.038). Mean(SD) postoperative TAP according to sesamoid station was 25.93º(6.2) for group 1, 23.83º(7.9) for group 2, and 18.75º(6.6) for group 3. No significant differences between groups were observed regarding IMA (p=0.25). There was a modest correlation between TAP change and PROMIS PF (rho = 0.046), PIF ( rho = -0.30), and PI (rho = -0.03). Conclusion: Our study suggests that MIS bunionectomy is an effective tool for reducing first-ray pronation in patients with HV. Although there was a statistically significant correlation between first-ray pronation and sesamoid station, our results showed that patients with higher first-ray pronation had less reduced sesamoids. Therefore, these should be considered separate deformities, and the sesamoid station shouldn’t be used as a guide for pronation correction. It appears that correction of the first-ray pronation is poorly associated with 1-year PROMIS scores. Consequently, future studies assessing mid-to-long-term effects of first-ray pronation on clinical outcomes, such as recurrence, are still warranted.

Category: Bunion; Midfoot/Forefoot Introduction/Purpose: Third-generation minimally invasive (MIS) bunionectomy requires a lateral shift of the metatarsal head, pushing the shaft into adduction and levering off the 1st-tarsometatarsal (TMT) joint. A previous study on plain radiographs reported postoperative 1st-TMT joint slippage in the transverse plane, with a medial subluxation of the 1st metatarsal base. However, risk factors and clinical implications have yet to be determined. This study sought to assess the prevalence of postoperative 1st-TMT joint slippage in the transverse plane and to identify associated risk factors using weight-bearing CT (WBCT) scans. In addition, the effect of 1st-TMT slippage on postoperative midshaft foot width was investigated. We hypothesized that postoperative 1st-TMT slippage in the transverse plane would be associated with preoperative 1st-TMT instability and increased postoperative midshaft foot width. Methods: Sixty-three consecutive patients who underwent MIS bunionectomy with available pre- and postoperative WBCT-scans were included. Radiographic measurements included hallux valgus angle(HVA), intermetatarsal angle(IMA), and midshaft foot width, measured from the 1st metatarsal shaft to the 5th metatarsal head on AP-foot radiographs. Tri-planar rotation angle(TAP), and 1st-TMT plantar-gap and medial-middle(MM) intercuneiform distances(mm) were obtained from WBCTs. Two raters measured pre- and postoperative 1st-TMT distances between the most lateral aspect of the medial cuneiform and 1st metatarsal base at the dorsal, central, and plantar thirds on axial cuts. The average corresponds to the overall 1st-TMT lateral distance, a measure of 1st-TMT slippage. Rater agreement was assessed. Paired t-tests were used to compare pre- and postoperative values. Logistic regression models were used to investigate the association of postoperative 1st-TMT lateral distance with potential risk factors (preoperative 1st-TMT lateral distance, 1st-TMT plantar-gap distance, IMA, TAP, and MM intercuneiform distance) and postoperative midshaft foot width. Results: The interobserver reliability of the 1st-TMT lateral distance was excellent (r=0.97). Mean (SD) 1st-TMT lateral distance increased from 0.26 mm(0.4) to 1.33 mm(0.9) after surgery(P< 0.05). Postoperative 1st-TMT lateral distance was > 2 mm in 15 patients(24%), and > 1 mm in 33(52%). Mean(SD) dorsal 1st-TMT lateral distance (2.7mm[1.3]) was significantly higher than central (0.85mm[1.1]) and plantar (0.55mm[0.99]) 1st-TMT lateral distances. Mean(SD) midshaft foot width increased from 80.04mm(6.7) to 84.25mm(6.1) postoperatively (P< 0.05). Regression analysis showed that pre- and postoperative 1st-TMT lateral distances were correlated (Coef=0.64,P=0.02), and identified a 1 mm increase in postoperative 1st-TMT lateral distance with each 0.63 mm increase in preoperative 1st-TMT plantar-gap distance (Coef=0.63,P=0.008). A significant positive correlation was also observed between postoperative 1st-TMT lateral distance and postoperative midshaft foot width (Coef=1.43,P< 0.05). Conclusion: Our study suggests a possible association between postoperative 1st-TMT joint slippage and preoperative 1st-TMT multiaxial instability following MIS bunionectomy. This raises an important question as to whether alternative techniques, such as modified Lapidus, should be preferred over MIS bunionectomy in patients with 1st-TMT instability. Notably, medial slippage was significantly higher at the dorsal aspect of the 1st-TMT joint, suggesting a component of rotational instability. It appears that 1st-TMT slippage is associated with a wider midshaft foot width postoperatively, and patients should be warned about it. Future studies assessing mid-to-long-term effects of 1st-TMT slippage, like recurrence or degenerative changes, are warranted.

Background: Both an open cheilectomy with a Moberg osteotomy and percutaneous cheilectomy have been successfully used to treat hallux rigidus and preserve motion. However, there have been no studies that have compared these 2 procedures using validated patient-reported outcomes such as the Patient Reported Outcome Measurement Information System. Methods: A retrospective review of hallux rigidus patients between January 2016 and July 2021 collected 48 percutaneous cheilectomy (PC) patients and 71 open cheilectomy with Moberg (OCM) patients. Preoperative and minimum 1-year postoperative PROMIS scores were collected. Results: The OCM and PC cohorts did not have significant differences in their postoperative PROMIS scores. Both cohorts had modest but significant improvements postoperatively in the physical function, pain interference, and pain intensity domains. The OCM group had a larger degree of improvement in physical function, pain interference, and pain intensity ( P = .015, .011, .001, respectively). No significant difference was identified in the reoperation rate. Conclusion: Patients undergoing an OCM had worse preoperative PROMIS scores and a modestly greater change in patient-reported outcomes than patients undergoing a PC. Level of Evidence: Level III, retrospective review.