Defining the patient acceptable symptom state using PROMIS following reconstruction of the progressive collapsing foot deformity.

BACKGROUND: The patient acceptable symptom state (PASS) represents the threshold beyond which patients are satisfied with their outcome. This study aimed to define PASS thresholds for progressive collapsing foot deformity (PCFD) reconstruction using Patient-Reported Outcomes Measurement Information System (PROMIS) scores and anchor question responses. METHODS: This retrospective study consisted of 109 patients who underwent flexible PCFD reconstruction, had preoperative and 2-year postoperative PROMIS scores, and 2-year postoperative anchor question responses. ROC curve analyses were performed to quantify PASS thresholds. RESULTS: PASS thresholds for the PROMIS Physical Function (PF) and Pain Interference (PI) domains were found to be lower and higher, respectively, than population norms. Furthermore, patients with higher preoperative PROMIS PF scores or lower preoperative PROMIS PI scores had a significantly higher likelihood of achieving the PASS thresholds. CONCLUSION: In addition to guiding future outcomes research, these results may help surgeons optimize treatment for PCFD and better manage patient expectations. LEVEL OF EVIDENCE: III, retrospective cohort study.

Finite Element Modeling of Planus and Rectus Foot Types for the Study of First Metatarsophalangeal and First Metatarsocuneiform Joint Contact Mechanics.

The foot is a highly complex biomechanical system for which finite element (FE) modeling has been used to evaluate its loading environment. However, there is limited knowledge of first metatarsophalangeal (MTP) and first metatarsocuneiform (MTC) joint contact mechanics. Our goal was to develop a framework for FE modeling of the medial forefoot which could accurately predict experimental measurements of first MTP and first MTC joint loading. Simulations of planus and rectus foot types were conducted for midstance of gait. A custom-built force-controlled cadaveric test-rig was used to derive intracapsular pressure sensor measurements of contact pressure, force, and area during quasi-static loading. The FE model was driven under the same boundary and loading conditions as the cadaver. Mesh sensitivity analyses and best-fit calibrations of moduli for first MTP and first MTC joint cartilage were performed. Consistent with previous experimental research, a lower compressive modulus was best-fit to the first MTP compared to first MTC joint at 10 MPa and 20 MPa, respectively. Mean errors in contact pressures, forces, and areas were 24%, 4%, and 40% at the first MTP joint and 23%, 12%, and 19% at the first MTC joint, respectively. The present developmental framework may provide a basis for future modeling of first MTP and first MTC joint contact mechanics. This study acts as a precursor to validation of realistic physiological loading across gait to investigate joint loading, foot type biomechanics, and surgical interventions of the medial forefoot.

Chronic Achilles Tendon Ruptures: From Bracing Treatment to Complex Reconstruction.

The optimal management of chronic Achilles tendon injuries continues to be debated. The tension-length relationship and intrinsic viscoelasticity of the native tendon that allows efficient propulsion during ambulation are difficult to restore once the tendon has been injured. Missed or misdiagnosed injuries or failure of surgical or nonsurgical management of acute Achilles tendon ruptures can lead to the tendon healing in an elongated position or lack of healing altogether. This condition results in persistent weakness, pain, and functional debilitation for the patient. Understanding the tendon and muscle properties will inform the choice of treatment. Nonsurgical treatment options are primarily bracing treatment and physical therapy. Surgical treatment options involve direct repair, reconstruction with local tissue, allograft or autograft, and tendon transfer. Various options and techniques for reconstruction are described to assist in optimizing management of this challenging clinical problem.

The influence of concomitant hammertoe correction on postoperative outcomes in patients undergoing hallux valgus correction.

BACKGROUND: Patients with hallux valgus often develop secondary hammertoe deformities of the lesser toes. Operative management of bunions with hammertoe can be more extensive; however, it is unclear whether this affects patient-reported outcomes. The aim of this study was to compare postoperative patient-reported outcome measures and radiographic outcomes between patients who underwent isolated bunion correction and patients who underwent simultaneous bunion and hammertoe correction. METHODS: Preoperative, postoperative, and change in Patient-Reported Outcomes Measurement Information System (PROMIS) scores were compared between patients who underwent isolated hallux valgus correction and those who underwent concomitant hammertoe correction. Radiographic measures including hallux valgus angle (HVA), intermetatarsal angle (IMA), distal metatarsal-articular angle (DMAA), and Meary's angle were also compared. Targeted minimum-loss estimation (TMLE) was used for statistical analysis to control for confounders. RESULTS: A total of 221 feet (134 isolated bunion correction, 87 concomitant hammertoe correction) with a minimum of 12 months follow-up were included in this study. Both cohorts demonstrated significant improvements in the physical function, pain interference, pain intensity, and global physical health PROMIS domains (all p < 0.001). However, patients in the concomitant hammertoe cohort had significantly less improvements in pain interference and pain intensity (p < 0.01, p < 0.05 respectively). The concomitant hammertoe cohort also had significantly higher postoperative pain interference scores than the isolated bunion cohort (p < 0.01). Radiographic outcomes did not differ between the two groups. CONCLUSION: While both isolated bunion correction and concomitant hammertoe correction yielded clinically significant improvements in patient reported outcomes and normalized radiographic parameters, patients undergoing simultaneous bunion and hammertoe correction experienced substantially less improvement in postoperative pain-related outcomes than those who underwent isolated bunion correction.

Pronation on weightbearing radiographs does not correlate with pronation from weightbearing CT scans.

INTRODUCTION: In hallux valgus (HV), first metatarsal pronation is increasingly recognized as an important aspect of the deformity. The purpose of this study was to compare pronation in HV patients determined from the shape of the lateral head of the first metatarsal on AP weightbearing radiographs with pronation calculated from weightbearing CT (WBCT) scans. METHODS: Patients were included in this study if they had preoperative and 5-month postoperative WBCT scans and corresponding weightbearing AP radiographs of the affected foot. Pronation of the first metatarsal on WBCT scans was measured using a 3D CAD model and the alpha angle and categorized into four groups on radiographs. Association between pronation groups on radiographs and WBCT scans was determined using Spearman correlation coefficients (rs) and by comparing mean WBCT pronation of the first metatarsal between plain radiograph pronation groups. RESULTS: Agreement between the two observers' pronation on radiographs was good (k = 0.634) and moderate (k = 0.501), respectively. There was no correlation between radiographic pronation and the 3D CAD model (rs < 0.15). Preoperatively, there was weak correlation between the alpha angle and the radiographic pronation groups (rs = 0.371, P = 0.048) although this relationship did not hold postoperatively (rs = 0.330, P = 0.081). There was no difference in mean pronation calculated on WBCT scans between the plain radiographic groups. CONCLUSION: Pronation of the first metatarsal measured on weightbearing AP radiographs had moderate interobserver agreement and was only weakly associated with pronation measured from WBCT scans. These results suggest that first metatarsal pronation measured on weightbearing radiographs is not a substitute for pronation measured on WBCT scans. LEVEL OF EVIDENCE: III, retrospective cohort study.

The use of three-dimensional biometric Foot and Ankle Offset to predict additional realignment procedures in total ankle replacement.

BACKGROUND: Decision to perform associated corrective alignment procedures in patients undergoing total ankle replacement (TAR) is commonly made intraoperatively. The Foot and Ankle Offset (FAO) can evaluate multiplanar deformity and be an effective instrument in surgical planning. This study objective was to assess the ability of this tool to predict the need for additional realignment procedures at the time of TAR. METHODS: In this retrospective study, we enrolled 21 patients who underwent TAR and had preoperative WBCT studies. Two independent and blinded observers calculated the preoperative FAO using dedicated software. FAO measurements were compared between the different alignment groups (physiological alignment, valgus and varus). A multivariate regression analysis was used to assess the correlation between performed realignment procedures and FAO values. RESULTS: Mean preoperative FAO was 4.4% (95%CI = 1.4-7.5). The number of osseous realignment procedures needed was found to correlate positively and significantly with FAO (p = .001). The number of osseus procedures needed was significantly higher in patients with valgus malalignment (p = .009). Patients with valgus malalignment needing a medial column procedure had a relative risk of 6.3 when compared to varus malalignment patients (p = .02). CONCLUSION: The number of additional bony realignment procedures performed at the time of TAR significantly correlated with preoperative FAO and that the number of osseus procedures needed was significantly higher in patients with valgus malalignment. Such biometric tools may enhance the preoperative assessment and surgical planning for patients undergoing TAR, with the potential to optimize surgical outcomes.

Combined weightbearing CT and MRI assessment of flexible progressive collapsing foot deformity.

BACKGROUND: The objective of this study was to evaluate the correlation between Weightbearing CT (WBCT) markers of pronounced peritalar subluxation (PTS) and MRI findings of soft tissue insufficiency in patients with flexible Progressive Collapsing Foot Deformity (PCFD). We hypothesized that significant correlation would be found. METHODS: Retrospective comparative study with 54 flexible PCFD patients. WBCT and MRI variables deformity severity were evaluated, including markers of pronounced PTS, as well as soft tissue degeneration. A multiple regression analysis and partition prediction models were used to evaluate the relationship between bone alignment and soft tissue injury. P-values of less than .05 were considered significant. RESULTS: Degeneration of the posterior tibial tendon was significantly associated with sinus tarsi impingement (p = .04). Spring ligament degeneration correlated to subtalar joint subluxation (p = .04). Talocalcaneal interosseous ligament involvement was the only one to significantly correlate to the presence of subfibular impingement (p = .02). CONCLUSION: Our results demonstrated that WBCT markers of pronounced deformity and PTS were significantly correlated to MRI involvement of the PTT and other important restraints such as the spring and talocalcaneal interosseus ligaments. LEVEL OF EVIDENCE: Level III, Retrospective comparative study.

Weight-bearing radiographs and cone-beam computed tomography examinations in adult acquired flatfoot deformity.

BACKGROUND: Optimal characterization of Adult acquired flatfoot deformity (AAFD) on two-dimensional radiograph can be challenging. Weightbearing Cone Beam CT (CBCT) may improve characterization of the three-dimensional (3D) structural details of such dynamic deformity. We compared and validated AAFD measurements between weightbearing radiograph and weightbearing CBCT images. METHODS: 20 patients (20 feet, right/left: 15/5, male/female: 12/8, mean age: 52.2) with clinical diagnosis of flexible AAFD were prospectively recruited and underwent weightbearing dorsoplantar (DP) and lateral radiograph as well as weightbearing CBCT. Two foot and ankle surgeons performed AAFD measurements at parasagittal and axial planes (lateral and DP radiographs, respectively). Intra- and Inter-observer reliabilities were calculated by Intraclass correlation (ICC) and Cohen's kappa. Mean values of weightbearing radiograph and weightbearing CBCT measurements were also compared. RESULTS: Except for medial-cuneiform-first-metatarsal-angle, adequate intra-observer reliability (range:0.61-0.96) was observed for weightbearing radiographic measurements. Moderate to very good interobserver reliability between weightbearing radiograph and weightbearing CBCT measurements were observed for the following measurements: Naviculocuneiform-angle (ICC:0.47), Medial-cuneiform-first-metatarsal-gapping (ICC:0.58), cuboid-to-floor-distance (ICC:0.68), calcaneal-inclination-angle(ICC:0.7), axial Talonavicular-coverage-angle(ICC:0.56), axial Talus-first-metatarsal-angle(ICC:0.62). Comparing weightbearing radiograph and weightbearing CBCT images, statistically significant differences in the mean values of parasagittal talus-first-metatarsal-angle, medial-cuneiform-first-metatarsal-angle, medial-cuneiform-to-floor-distance and navicular-to-floor-distance was observed (P < 0.05). CONCLUSION: Moderate to very good correlation was observed between certain weightbearing radiograph and weightbearing CBCT measurements, however, significant difference was observed between a number of AAFD measurements, which suggest that 2D radiographic evaluation could potentially underestimate the severity of AAFD, when compared to 3D weightbearing CT assessment.

Accuracy of patient-specific instrumentation in total ankle arthroplasty: A comparative study.

BACKGROUND: Patient-specific instrumentation (PSI) for TAA is a novel technology with several potential benefits. The primary goal of this study was to compare the use of PSI with the standard referencing guide (SRG) in regards to accuracy of tibial implant positioning. Operative time, fluoroscopy time and accuracy of PSI preoperative reports were also evaluated. METHODS: A retrospective analysis of 99 patients who underwent a primary TAA with the INFINITY prosthesis (Wright Medical, Memphis, TN) was performed. Patients were divided in two groups based on the type of instrumentation used during the TAA (75 in the PSI group vs 24 in the SRG group). There was no significant difference between groups in regards to age at the time of surgery (P=0.122), sex (P=0.138), number of concomitant procedures performed during surgery (P=0.567) and etiology (P=0.841). However, preoperative deformity was significantly smaller in the PSI group (P=0.002). RESULTS: Tibial implant positioning was similar between groups. In the coronal plane, the absolute deviation of the tibial implant from the intended alignment was 1.7±1.4° for the SRG and 1.6±1.2° for PSI (P=0.710). In the sagittal plane, the absolute alignment deviation of the tibial implant was 1.8±1.4° for the SRG and 1.9±1.5° for PSI (P=0.675). Operative time (167 vs 190min, P=0.040) and fluoroscopy time (85 vs 158s, P<0.001) were significantly decreased in the PSI group. The PSI preoperative plan report correctly predicted the implant size in 73% of cases for the tibial component and in 51% of cases for the talar component. CONCLUSIONS: PSI provided similar tibial component alignment as standard instrumentation. Additionally, PSI preoperative plan reports were poor predictors of implant sizing. Therefore, the final decision should always be based on surgeon's experience in order to prevent errors in implant sizing and positioning. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Readiness for Discharge After Foot and Ankle Surgery Using Peripheral Nerve Blocks: A Randomized Controlled Trial Comparing Spinal and General Anesthesia as Supplements to Nerve Blocks.

BACKGROUND: Neuraxial anesthesia is often viewed as superior to general anesthesia but may delay discharge. Comparisons do not typically use multimodal analgesics and nerve blockade. Combining nerve blockade with general anesthesia may reduce pain, opioid consumption, and nausea. We hypothesized that general anesthesia (with nerve blocks) would lead to earlier readiness for discharge, compared to spinal anesthesia (with nerve blocks). METHODS: All patients underwent ambulatory foot and ankle surgery, with a predicted case duration of 1-3 hours. All patients received popliteal and adductor canal nerve blocks using bupivacaine and dexamethasone. No intraoperative opioids were administered. All patients received ondansetron, dexamethasone, ketamine, and ketorolac. Patients, data collectors, and the data analyst were not informed of group assignment. Patients were randomized to spinal or general anesthesia with concealed allocation. Spinal anesthesia was performed with mepivacaine and accompanied with propofol sedation. After general anesthesia was induced with propofol, a laryngeal mask airway was inserted, followed by sevoflurane and propofol. Time until ready for discharge, the primary outcome, was compared between groups after adjusting for age and surgery time using multivariable unconditional quantile regression. Secondary outcomes compared at multiple timepoints were adjusted for multiple comparisons using the Holm-Bonferroni step-down procedure. RESULTS: General anesthesia patients were ready for discharge at a median of 39 minutes earlier (95% confidence interval, 2-75; P = .038) versus spinal anesthesia patients. Patients in both groups met readiness criteria for discharge substantially before actual discharge. Pain scores at rest were higher among general anesthesia patients 1 hour after leaving the operating room (adjusted difference in means, 2.1 [95% confidence interval, 1.0-3.2]; P < .001). Other secondary outcomes (including opioid use, opioid side effects, nausea, headache, sore throat, and back pain) were not different. CONCLUSIONS: General anesthesia was associated with earlier readiness for discharge, but the difference may not be clinically significant and did not lead to earlier actual discharge. Most secondary outcomes were not different between groups. The choice of spinal or general anesthesia as an adjunct to peripheral nerve blockade can reflect patient, clinician, and institutional preferences.

Evaluation of peritalar subluxation in adult acquired flatfoot deformity using computed tomography and weightbearing multiplanar imaging.

BACKGROUND: The aim of this study was to assess the inferior talus-superior talus (inf-tal-sup-tal) angle (previously proven reliable in multiplanar-weight bearing imaging (MP-WB)) on both computed tomography (CT) and MP-WB scans. We sought to compare the angle between the two modalities in both AAFD and control groups, as well as to compare the groups to each other. METHODS: Inf-tal-sup-tal angles were compared between a stage II AAFD group (n=38) with routine MP-WB and CT scans and a control group (n=20) with preoperative CT scans for lisfranc injuries and normal hindfoot alignment after healing. RESULTS: The CT inf-tal-sup-tal angle was significantly greater in AAFD compared to control (AAFD, 12±6; control, 5±4; p<0.001), but was even greater with MP-WB. There was no significant correlation between inf-tal-sup-tal angles on MP-WB and CT (Pearson's=0.29, p=0.08). CONCLUSIONS: MP-WB imaging proved to be correlated more strongly with AAFD than CT by revealing greater hindfoot valgus. This confirmed that CT scans are useful in predicting AAFD, but cannot be used as a surrogate for MP-WB scans.

Sonography of Morton Neuromas: What Are We Really Looking At?

OBJECTIVES: To determine what accounts for the sonographic appearance of a Morton neuroma by correlating preoperative sonograms with the sonographic appearance of the resected surgical specimen, the surgical findings, and the pathologic examination. METHODS: Ten Morton neuromas that had preoperative sonograms underwent postoperative specimen sonography and histologic evaluation. The appearance and size of the neuromas were compared between the preoperative and postoperative specimen images and were compared to the surgical and pathologic appearances. RESULTS: Preoperative images showed a fibrillar echogenic nerve coursing into a heterogeneous hypoechoic mass measuring 14.3 mm in average length (range, 9.0-24.0 mm) that contained a round, mildly echogenic mass within it measuring 7.6 mm in average length (range, 4.5-12.0 mm). Surgically, the specimens showed scarred intermetatarsal bursas and tangled vessels surrounding the nerve. Specimen sonography showed echogenic focal enlargement of the nerve at the site of the neuroma, measuring 6.8 mm in average length (range, 3.5-11.0 mm). The size of the resected neuroma was smaller than the hypoechoic mass on the presurgical images (P < .001). Within the hypoechoic mass, the small echogenic focus showed no difference in size compared to the specimen (P = .40), but the shape of the echogenic specimen was fusiform, whereas the preoperative appearance was round. Histologically, the resected specimens showed sclerosis and mucoid degeneration of the nerve fascicles and fibrotic thickening of the perineurium. CONCLUSIONS: The hypoechoic heterogeneous mass that is referred to as a Morton neuroma sonographically is really a "neuroma-bursal complex" that is much larger than the actual neuroma itself.

Conversion of ankle autofusion to total ankle replacement using the Salto XT revision prosthesis.

Few reports in the literature have described the conversion of a surgically fused ankle to a total ankle replacement. The takedown of an autofusion and conversion to a prosthesis has not been described. We report the case of a patient with severe rheumatoid arthritis with an ankle autofusion fixed in equinus and severe talonavicular arthritis that was converted to ankle replacement using the Salto XT revision system. We describe the reasons why the decision was made to perform total ankle arthroplasty while concomitantly fusing the talonavicular joint, and discuss the rationale of the various surgical treatment options considered. We describe the clinical and radiographic outcomes achieved in this case. At 12 months post-operatively the patient reported significant reduction of pain, increased FAOS scores and had increased ankle range of motion.

A case of acute tarsal tunnel syndrome following lateralizing calcaneal osteotomy.

Surgical correction of hindfoot varus is frequently performed with a lateral displacement calcaneal osteotomy. It has rarely been associated with iatrogenic tarsal tunnel syndrome in patients with pre-existing neurological disease. We report the first case of acute postoperative tarsal tunnel syndrome in a neurologically intact patient with post-traumatic hindfoot varus. Early diagnosis and emergent operative release afforded an excellent clinical outcome. Imaging studies can help outrule a compressive hematoma and assess for possible nerve transection; however it is paramount that a high index of suspicion is utilized with judicious operative intervention to minimize long-term sequelae.

Influence of Joint Line Level on Clinical Outcomes and Range of Motion in Total Ankle Arthroplasty.

BACKGROUND: Ankle arthritis leads to an elevated joint line compared to the nonarthritic ankle, as measured by the "joint line height ratio" (JLHR). Previous work has shown that the JLHR may remain elevated after total ankle arthroplasty (TAA). However, the clinical impact of this has yet to be determined. This study assessed the correlation between postoperative JLHR, post-TAA range of motion (ROM), and 1-year Patient-Reported Outcome Measurement Information System (PROMIS) scores. METHODS: A retrospective review of 150 patients who underwent primary TAA was performed. Preoperative and postoperative JLHR, as well as postoperative dorsiflexion, plantarflexion, and total ROM, was calculated on weightbearing radiographs at a minimum of 1-year follow-up. Correlation between JLHR, post-TAA ROM, and 1-year PROMIS scores was investigated using Pearson correlation and multiple linear regression models. Interobserver reliability for the JLHR was also calculated. RESULTS: Interobserver reliability for the JLHR was excellent (r = 0.98). Mean (SD) JLHR changed from 1.66 (0.45) to 1.55 (0.26) after TAA (P < .001), indicating that the joint line was lowered after TAA. An elevated joint line was correlated with decreased post-TAA dorsiflexion (r = -0.26, P < .001), total ROM (r = -0.18, P = .025), and worse 1-year PROMIS physical function (r = -0.22, P = .046), pain intensity (r = 0.22, P = .042), and pain interference (r = 0.29, P = .007). There was no correlation between the JLHR and post-TAA plantarflexion (r = -0.025, P = .76). Regression analysis identified a 0.5-degree reduction in post-TAA dorsiflexion with each 0.1-unit increase in JLHR (Coeff. = -5.13, P = .005). CONCLUSION: In this patient cohort, we found that an elevated joint line modestly correlated with decreased postoperative dorsiflexion, total ROM, and worse 1-year PROMIS scores. These data suggest that effort likely should be made toward restoring the native joint line at the time of TAA. In addition, future studies investigating the clinical outcomes after TAA may consider including a measure of joint line height, such as the JLHR, because we found it was associated with patient-reported outcomes. LEVEL OF EVIDENCE: Level III, retrospective review of prospectively collected data.

Preoperative Degenerative Changes at the Tibial Sesamoid-Metatarsal Joint in Hallux Valgus: Association With Postoperative Patient-Reported Outcomes After Modified Lapidus Procedure.

Background: Degenerative changes at the sesamoid-metatarsal joints (SMJs) may be a source of pain following hallux valgus surgery. The aims of this study were to describe degenerative changes at the SMJs on weightbearing computed tomography (WBCT) scans and, secondarily, investigate their association with 1-year patient-reported outcome scores following a modified Lapidus procedure for hallux valgus. We hypothesized that reduced joint space in the SMJs would correlate with worse patient-reported outcomes. Methods: Fifty-seven hallux valgus patients who underwent a modified Lapidus procedure had preoperative and minimum 5-month postoperative WBCT scans, and preoperative and at least 1-year postoperative PROMIS physical function (PF), pain interference, and pain intensity scores were included. Degenerative changes at the SMJs were measured using distance mapping between the sesamoids and first metatarsal head on preoperative and postoperative WBCT scans. The minimum and average distances between the first metatarsal head and tibial sesamoid (tibial-SMJ) for each patient preoperatively and postoperatively were measured. Sesamoid station was measured on WBCT scans using a 0 to 3 grading system. Linear regression was used to investigate the correlations between minimum preoperative and postoperative tibial-SMJ distances and 1-year postoperative PROMIS scores. Results: The median minimum and average tibial-SMJ distances increased from 0.82 mm (interquartile range [IQR] 0.40-1.03 mm) and 1.62 mm (IQR 1.37-1.75 mm) preoperative to 1.09 mm (IQR 0.96-1.23 mm) and 1.73 mm (IQR 1.60-1.91 mm) postoperative (P < .001 and P < .001), respectively. In a subset of patients with complete sesamoid reduction, we found an association between preoperative minimum tibial-SMJ distance and 1-year postoperative PROMIS PF scores (coefficient 7.2, P = .02). Conclusion: Following the modified Lapidus procedure, there was a statistically significant increase in the tibial-SMJ distance. Additionally, in patients with reduced sesamoids postoperatively, reduced preoperative tibial-SMJ distance correlated with worse PROMIS PF scores. Level of Evidence: Level IV, case series.

Postoperative Medial Malleolar Fractures in Total Ankle Replacement Are Associated With Decreased Medial Malleolar Width and Varus Malalignment: A Case-Control Study.

BACKGROUND: There are limited data regarding risk factors associated with periprosthetic medial malleolar fractures in total ankle arthroplasty (TAA). This case-control study aimed to identify the risk factors and analyze the effect of prophylactic screw fixation in preventing a medial malleolar fracture after TAA. METHODS: A case-control study was conducted on 149 patients who underwent primary TAA. Twenty patients with postoperative medial malleolar fractures >4 weeks postoperatively (cases) were identified. An additional 129 patients (controls) were randomly selected from the TAA database. Radiographic evaluation included tibial component coronal alignment and postoperative medial malleolar width. Demographics and radiographic variables were compared between cohorts. Logistic regression was used to investigate the association between medial malleolar fracture and postoperative coronal alignment, medial malleolar width, and prophylactic fixation of the medial malleolus. RESULTS: Mean (SD) medial malleolar width was significantly smaller in the fracture cohort (8.52 mm [1.6]) than in the control group (11.78 mm [1.74]) (P < .001). Mean (SD) tibial component coronal alignment was 92.17 degrees (2.77) in the fracture cohort and 90.21 degrees (1.66) in the control group (P = .002). Regression analysis identified a significant negative association between postoperative medial malleolar width and the probability of fracture (OR = 0.06, 95% CI 0.01, 0.26, P < .001). Varus malalignment of the tibial component was positively associated with the probability of fracture (OR = 1.90, 95% CI 1.27, 2.86, P = .002). Prophylactic screw fixation resulted in more than 90% reduction in the odds of a fracture (OR = 0.04, 95% CI 0.01, 0.45, P = .01). ROC curve analysis determined a medial malleolar width of 10.3 mm as a potential threshold for predicting fracture. CONCLUSION: Decreased medial malleolar width and postoperative varus malalignment were associated with an increased risk of postoperative medial malleolar fracture. Therefore, surgeons should consider prophylactic screw fixation in patients with a medial malleolar width <10.3 mm or at risk of postoperative varus deformity.

Correlation of Clinical Outcomes and Relative Position of the First Metatarsal After the Modified Lapidus Procedure.

BACKGROUND: Hallux valgus is a complex 3-dimensional deformity, and the modified Lapidus is a commonly used procedure to correct moderate to severe cases. Shortening and elevation of the first ray can occur with this procedure, which may result in increased pressure on the lesser metatarsal heads. However, there is currently no consensus regarding an accepted length and elevation of the first ray following the modified Lapidus. Therefore, the purpose of this study is to evaluate the impact of the position of the first ray on patient-reported outcome measures. METHODS: This retrospective study identified 68 patients (72 feet) who underwent the modified Lapidus bunionectomy over a 4-year period at a single institution with a median follow-up of 24 months (range, 11-35.6 months). Patients were included if they were over 18 years of age, had pre- and postoperative weightbearing computed tomography (WBCT) scans, and preoperative and minimum 1-year postoperative Patient-Reported Outcome Measurement Information System (PROMIS) scores. PROMIS scores from 6 domains including physical function, pain interference, pain intensity, global physical health, global mental health, and depression were evaluated and compared pre- and postoperatively. Radiographic parameters were measured and compared before and after surgery. Paired t tests were used to evaluate the significance of pre- to postoperative changes. Differences between cohorts were compared using Mann-Whitney U test for continuous variables or Fisher exact test for categorical variables. Correlation between radiographic measurements and patient-reported outcomes were assessed using the Spearman rank rho estimate and visualized with scatterplots with a linear regression. RESULTS: PROMIS physical function, pain interference, pain intensity, and global physical health improved significantly following the modified Lapidus (all P < .001); however, scores did not show any significant correlation with shortening of the first ray up to a maximum shortening of 4.8 mm. The length of the first metatarsal relative to the second decreased by an average of 2.7 mm following the procedure when measured on WBCT (P < .001), and 2.6 mm when measured on plain radiographs (P < .001). No significant elevation of the first ray was observed postoperatively. CONCLUSION: This study revealed that the Lapidus bunionectomy resulted in significantly improved pain and physical function at short-term follow-up. The amount of first ray shortening and elevation that occurred in this cohort did not adversely affect patient-reported outcomes.

Passive Eversion Assessment for Progressive Collapsing Foot Deformity After Lateral Column Lengthening: A Cadaveric Biomechanical Study.

BACKGROUND: Reduced hindfoot eversion motion has been proposed as a cause of increased lateral foot pressure following lateral column lengthening (LCL) for progressive collapsing foot deformity (PCFD). A subjective intraoperative assessment of passive eversion has been suggested to help evaluate correction; however, it is unclear how passive eversion correlates with objective measurements of foot stiffness. Our objectives were to quantify the relationship between the maximum passive eversion in hindfoot joints following LCL with plantar pressure during stance and to determine the influence of wedge size on these outcomes. METHODS: Ten cadaveric specimens extending from the mid-tibia distally were tested on a 6-degrees-of-freedom robot to simulate the stance phase of level walking. Five conditions were tested: intact, simulated PCFD, and 3 LCL wedge conditions (4, 6, and 8 mm). Outcomes included the lateral-to-medial forefoot plantar pressure (LM) ratio during stance and the maximum passive eversion measured in the hindfoot joints. Simple linear regressions were performed to evaluate relationships between outcomes and wedge sizes. RESULTS: A strong negative relationship was found between passive subtalar eversion and the LM ratio during stance (r[38] = -0.46; p = 0.0007), but not between passive talonavicular eversion and the LM ratio (r[38] = -0.02; p = 0.37). Wedge size was strongly related to subtalar eversion (r[38] = -0.77; p < 0.0001), talonavicular eversion (r[38] = -0.55; p = 0.0003), and the LM ratio (r[38] = 0.70; p < 0.0001). Increased wedge size resulted in average decreases in subtalar and talonavicular eversion of 1.0° (95% confidence interval [CI]: 0.8° to 1.3°) and 1.2° (95% CI: 0.6° to 1.6°), respectively. Increased wedge size also increased the LM ratio by 0.38 (95% CI: 0.25 to 0.50), indicating a lateral shift in plantar pressure. CONCLUSIONS: Decreased hindfoot eversion following LCL was related to increased lateral plantar pressure during stance. Increasing wedge size correlated with decreasing passive hindfoot eversion and increasing lateral plantar pressure, suggesting that intraoperative preservation of eversion motion may be important for preventing excessive lateral loading. CLINICAL RELEVANCE: To avoid overcorrection or undercorrection of the deformity, hindfoot eversion assessment in addition to radiographic evaluation may be important for optimizing the amount of lengthening to achieve successful LCL.