Background: Lateral bony impingement is a major cause of lateral foot pain in progressive collapsing foot deformity (PCFD). Weightbearing computed tomography (WBCT) provides better sensitivity than standard radiographs for detecting impingement. However, many orthopaedic centers have not yet acquired WBCT imaging. This study aimed to (1) investigate the correlation of common radiographic parameters measured on standard weightbearing radiographs with talocalcaneal and calcaneofibular distance assessed with WBCT and (2) establish radiographic cutoff values to detect bony impingement as identified on WBCT. Methods: Ninety-one patients treated for PCFD with standard preoperative radiographs and WBCT were identified. Patients with asymmetric ankle arthritis (talar tilt >2 degrees) were excluded. The talocalcaneal distance at the sinus tarsi and calcaneofibular distance were measured in multiplanar reconstructed WBCT images. Impingement was defined as direct abutment between bones. The relationships between WBCT measurements and 4 common parameters (talonavicular coverage angle [TNC], talo–first metatarsal angle, calcaneal pitch, and hindfoot moment arm [HMA]) in standard radiographs were assessed with Pearson correlations. Receiver operating characteristic curve analysis evaluated the ability of radiographic cutoffs to detect sinus tarsi or calcaneofibular bony impingement, and the area under curve (AUC), sensitivity, specificity, negative and positive predictive value (PPV) were calculated. Results: Talocalcaneal distance narrowing at the sinus tarsi strongly correlated with TNC ( r = 0.64, P < .001), and the calcaneofibular distance narrowing correlated with the HMA moderately yet best among the parameters ( r = 0.55, P < .001). TNC (AUC = 0.837, 95% CI 0.745-0.906) and HMA (AUC=0.959, 95% CI 0.895-0.989) provided the best predictive ability for sinus tarsi and calcaneofibular bony impingement, respectively. A TNC threshold of 41.2 degrees had a 100% PPV for predicting sinus tarsi impingement, whereas an HMA threshold of 38.1 mm had a 100% PPV for calcaneofibular impingement. Conclusion: This study provides evidence that TNC and HMA measurements made on standing radiographs could be used to indicate potential lateral bony impingement in PCFD. Narrowing of talocalcaneal distance best correlated with abduction deformity of the foot, and the narrowing of calcaneofibular distance was best correlated with valgus hindfoot deformity. Level of Evidence: Level III, case control study.

Background: The Cadence Total Ankle System is a 2-component, fixed-bearing fourth-generation total ankle arthroplasty (TAA) system that was introduced for clinical use in 2016. The purpose of this study was to report non–inventor, non–industry funded survivorship, radiographic and clinical outcomes, and early complications following use of this implant at a minimum of 2 years. Methods: This single-center retrospective study included patients who underwent TAA by 2 surgeons with this novel fixed-bearing system between January 2017 and September 2018. Forty-eight patients were evaluated at an average of 33.6 months. Radiographic outcomes included preoperative and postoperative tibiotalar angle on anteroposterior radiographs of the ankle, sagittal tibial angle (STA) on lateral radiographs of the ankle, and periprosthetic lucency formation and location. Revision and reoperation data were collected, and patient-reported outcomes were assessed using Patient Reported Outcomes Measurement Information System (PROMIS). Subgroup analysis assessed associations between preoperative deformity, postoperative implant alignment, PROMIS scores, and periprosthetic lucency formation. Results: Survivorship of implant was 93.7%, with 3 revisions, 1 due to infection and 2 due to loosening of the implant (1 tibial and 1 talar component). Three patients had reoperations (6.3%): 2 for superficial infection and 1 for gutter debridement due to medial gutter impingement. Fifteen patients (35.8%) developed periprosthetic lucencies, all on the tibial side. PROMIS scores improved after surgery in all domains except Depression. Patients with significant postoperative periprosthetic lucency had worse postoperative PROMIS Physical function scores than patients without lucency ( P < .05). Conclusion: This study demonstrated excellent minimum 2-year clinical and radiographic outcomes and low revision and reoperation rates of this new fourth-generation TAA system. Future studies with longer follow-up, especially on patients with periprosthetic lucency, are necessary to investigate the long-term complications and understand the long-term functional and radiographic outcomes of this implant.

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Background: Patients with hallux rigidus who do not experience significant pain relief after cheilectomy often require a conversion to metatarsophalangeal (MTP) fusion. However, it is unclear whether the previous cheilectomy affects outcomes of the subsequent fusion. The aim of this study was to compare patient-reported outcomes and complications in patients undergoing MTP fusion for hallux rigidus between patients with a history of cheilectomy and those undergoing a fusion as a primary procedure. Methods: This retrospective cohort study included patients who underwent MTP fusion who had preoperative and minimum 1-year postoperative Patient Reported Outcomes Measurement Information System (PROMIS) scores. Patients were divided into a “primary MTP fusion” cohort and a “prior cheilectomy” cohort based on their history of a previous cheilectomy. Preoperative, postoperative, and improvement in PROMIS scores, along with rates of complications including nonunion, infection, interphalangeal (IP) joint pain, and removal of hardware were compared between groups. Results: The prior cheilectomy group had significantly lower preoperative physical function scores than the primary MTP fusion group ( P < .05). Postoperatively, the prior cheilectomy group had worse physical function ( P < .017) and global physical health ( P < .017) scores. However, there were no significant differences in pre- to postoperative change in PROMIS scores. There were no significant differences in rates of nonunion ( P = .99), infection ( P = .99), or hardware removal ( P = .99). More patients in the prior cheilectomy group had IP joint pain ( P = .034). Conclusion: This study found that a prior cheilectomy may not affect serious complication rates of a subsequent fusion, but it may be associated with worse baseline function. Overall, our results suggest that a prior failed cheilectomy does not influence the amount of improvement in function and pain from MTP fusion. Level of Evidence: Level III, retrospective cohort study.

Background: Digitally reconstructed radiographs (DRRs) generated from weightbearing computed tomography (WBCT) may potentially substitute for weightbearing plain radiographs (XRs) but have not been clinically validated. This study aims to test the reliability of 6 radiographic parameters of progressive collapsing foot deformity (PCFD) as measured on DRR, to investigate whether DRR represents comparably to XR through the same measurements, and to compare agreement of DRR and XR measurements of a standardized arch height parameter with reference measurements made on WBCT. Methods: DRR generated from preoperative WBCT of 71 patients (72 feet) treated surgically for PCFD were retrospectively compared with preoperative weight-bearing XR after exclusion criteria were applied. Six radiographic measurements were performed, including Meary angle, calcaneal pitch (CPA), medial cuneiform height (MCH), AP talar–first metatarsal angle (T-1MT), talonavicular coverage (TNCA), and talar incongruency (TIA). Arch height was measured on XR, DRR, and WBCT using a validated, standardized, navicular-based index. Intraclass correlation coefficients assessed DRR intraobserver and interobserver reliability. Paired samples t tests tested differences between XR and DRR. Bland-Altman limits of agreement analysis compared DRR and XR agreement with WBCT measurements. Results: Measurements were within standard PCFD ranges on XR and DRR. All measurements demonstrated excellent intrarater reliability and good to excellent interrater agreement, consistent with previous literature on XR. No differences were found for Meary, CPA, or TNCA. Minor differences were observed for MCH, T-1MT, and TIA. DRR measurements demonstrated greater agreement with WBCT than XR measurements. Conclusion: DRR from WBCT may be a promising substitute for XR in the clinical evaluation of PCFD. Radiographic measurements made on DRR demonstrated good to excellent reliability. Although small differences were found between XR and DRR for certain measurements, DRR more accurately represented medial arch anatomy compared to gold standard WBCT data than XR. If validated as a clinical substitute, DRR could eventually obviate XR where WBCT is available. Level of Evidence: Level III, retrospective cohort study.

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Background: Progressive collapsing foot deformity (PCFD) is a debilitating condition encompassing several interrelated, progressive deformities requiring a combination of reconstructive procedures. Few studies investigate returns to activity following flatfoot reconstruction, and existing studies only examine 1 or 2 of the numerous procedures employed. This study aims to provide the first generalizable assessment of returns to sports and physical activity following reconstruction surgery in patients with flexible flatfoot deformity. Methods: Patients aged 18-60 years who underwent reconstructive surgery between February 16 and May 19 for symptomatic flexible-stage flatfoot deformity were identified by registry review. Eighty-two of 113 eligible patients (73%) were reached at a mean 2.9 years (range, 2.0-5.4) of follow-up with mean age at surgery of 48.9 years (range, 18-59). Returns to physical activity were evaluated with a sports-specific survey. Clinical outcomes were evaluated with Patient-Reported Outcomes Measurement Information System (PROMIS) scores. Results: Patients reported participation in 21 specific sports and activities. One-fourth (25.6%) of patients (21/82) reported increased difficulty with physical activities postoperatively, 15.9% reported equal difficulty, and 58.5% (48/82) reported decreased difficulty. Median return times were 9-12 months for participation and 12-18 months to reach maximum preoperative participation levels. Improvements in Physical Function ( P= .001), Pain Interference ( P < .001), Pain Intensity ( P <.001), and Global Physical Health ( P = .004) were associated with increased satisfaction with respect to sports and physical activities. Discussion: This study investigated participation in specific sports and physical activities following flatfoot reconstruction. Our findings suggest mixed outcomes, where many patients reported life-changing improvements but many also experienced prolonged pain and difficulty after surgery. Some patients reported increased difficulty or inability to return to their preoperative maximum level of participation, indicating that flatfoot reconstructions can lead to athletic limitations. Conclusion: Although flatfoot reconstruction can be a powerful tool to increase patients’ capacity to engage in physical activity, in our cohort many patients had reduced physical activity outcomes. Level of Evidence: Level IV, retrospective case series.

Background: Patients with hallux valgus commonly present with concomitant flatfoot deformity. First-ray hypermobility, among other biomechanical factors, has been suggested as a potential link between these deformities. However, not all hallux valgus patients exhibit symptoms associated with flatfoot deformity, and the necessity of correcting the asymptomatic flatfoot at the time of hallux valgus correction is unclear. We aimed to investigate the relationship between asymptomatic flatfoot and patient-reported and radiographic outcomes after the Lapidus procedure. Methods: This study included 142 patients who underwent the Lapidus procedure for hallux valgus at a single institution. Sixty-one patients met radiographic criteria for flatfoot. No patients exhibited symptoms related to flatfoot deformity on review of clinical notes. Preoperative, minimum 1-year postoperative, and change in Patient-Reported Outcomes Measurement Information System (PROMIS) scores between asymptomatic flatfoot and control groups were compared. Radiographic outcomes including hallux valgus angle (HVA), intermetatarsal angle (IMA), Meary angle, talonavicular coverage angle (TNCA), and calcaneal pitch (CP) were compared. Results: Preoperatively, the flatfoot group had higher BMI 22.6 vs 24.6 ( P < .01) and IMA 15.32 vs 14.0 degrees ( P < .05). Both groups demonstrated preoperative to postoperative improvement in PROMIS physical function ( P < .01), pain interference ( P < .001), pain intensity ( P < .001), and global physical health ( P < .001). There were no preoperative or postoperative differences in PROMIS scores between groups. Postoperatively, there were no differences in HVA or IMA between groups; however, the flatfoot group exhibited greater deformity in Meary angle, TNCA, and CP (all P < .001). Conclusion: There were no significant postoperative differences in patient-reported outcomes of the Lapidus procedure between patients with and without asymptomatic flatfoot, and both groups achieved similar radiographic correction of their hallux valgus deformity. The Lapidus procedure appears to be a reasonable surgical option for hallux valgus correction in patients with asymptomatic flatfoot deformity. Level of Evidence: Level III, retrospective cohort study.