Progressive Collapsing Foot Deformity Research Articles

Change in Talar Axial Rotation and Pain Intensity Following Correction of Progressive Collapsing Foot Deformity.

The talus is more internally rotated within the ankle mortise in progressive collapsing foot deformity (PCFD) patients. However, no studies have investigated the change in talar axial rotation (AR) in PCFD postoperatively. The primary aim was to investigate the change in talar AR following PCFD reconstruction. Secondary aims were to determine whether talar AR changes were associated with other radiographic measurements or specific procedures, and whether postoperative talar AR was associated with 2-year patient-reported outcome scores. Twenty-seven patients older than 18 years who underwent flexible PCFD reconstruction with preoperative and at least 5-month postoperative weightbearing computed tomographic (WBCT) scans and radiographs and had preoperative and at least 2-year postoperative PROMIS scores were included. Patients with talonavicular fusions were excluded. Talar AR was the angle between the transmalleolar axis and talar axis on WBCT scans, with smaller angles representing more internal rotation as described by Kim et al. Hindfoot moment arm, Meary angle, fibulocalcaneal and talocalcaneal distance, subtalar middle facet uncoverage, and talonavicular angle were measured on radiographs. Postoperative talar AR was 49.7 degrees (IQR, 45.9, 57.3), which was more externally rotated than preoperative AR by a median of 8.3 degrees (IQR, 2.2, 15.7) (P > .001). The change in talar AR was not associated with changes in any radiographic parameter. Increasing external talar AR was associated with an increase in postoperative PROMIS pain intensity (rs = 0.38, 95% CI 0.00, 0.67). Lateral column lengthening and subtalar fusion procedures were not associated with changes in talar AR (P > .10). PCFD reconstruction results in external rotation of the talus within the ankle mortise. Kim et al found that control patients had approximately 40 to 60 degrees of talar AR, which is similar to this study's corrected position of the talus. However, increasing talar external rotation resulted in worse postoperative PROMIS pain intensity, suggesting the possibility of overcorrecting the internal AR deformity.

First Tarsometatarsal Alignment May Self-Correct After Triple Arthrodesis in Progressive Collapsing Foot Deformity.

Triple arthrodesis is commonly used to correct rigid progressive collapsing foot deformity (PCFD). These patients often have associated first tarsometatarsal (TMT) instability on lateral weightbearing radiographs. It has not been well established if it is necessary to add first TMT arthrodesis to adequately correct the overall deformity. This study retrospectively examined pre- and postoperative radiographs of PCFD patients with first TMT instability that were managed by triple arthrodesis alone. All triple arthrodesis cases were searched for a single surgeon between 2013 and 2021. Inclusion criteria were patients with PCFD who underwent triple arthrodesis without first TMT joint fusion. Preoperative radiographs were examined for first TMT joint instability, demonstrated by plantar gapping of the first metatarsal-medial cuneiform angle or first metatarsal dorsal subluxation at the TMT joint. Measurement of sagittal first metatarsal-medial cuneiform angle and first metatarsal subluxation as described by King and Toolan was performed. Twenty patients satisfied the inclusion criteria. Six patients did not demonstrate at least 30% improvement of one or both measurements of first TMT instability postoperatively and were considered failures. Fourteen patients demonstrated correction of their first TMT joint instability. Average follow-up was 5.0 (range, 1.8-9.4) years. The first metatarsal-medial cuneiform angle improved from 3.8 to 1.1 degrees (P < .05). The first metatarsal subluxation corrected from 4.1 to 1.5 mm (P < .05). One patient showed radiographic evidence of arthritis in the first TMT joint at final follow-up. Seventy percent of patients with PCFD with asymptomatic first TMT joint instability demonstrated correction of first TMT radiographic instability with isolated triple arthrodesis. This was maintained at 5-year mean follow-up. In cases of PCFD with medial column instability, triple arthrodesis alone may be adequate to restore overall alignment.

Correlation of progressive collapsing foot deformity with varus knee alignment in young adults – A case control study

BackgroundMajority of patients with Progressive Collapsing Foot Deformity(PCFD) have symptoms pertaining to the knee. Malalignment at the foot will have effects on the alignment of the knee. In this case control study, we compare the alignment of the knees between patients with PCFD and controls. MaterialsSixty subjects, 30 PCFD and 30 controls, underwent radiographs in which the tibiofemoral angle and radiological parameters of PCFD were assessed. Parameters of PCFD were correlated with the tibiofemoral angle. ResultsMean tibiofemoral angle was 3.8° among the cases and 4.8° among the controls which was statistically significant(P = 0.001). Varus knee alignment was seen in 41 out of 60 limbs with PCFD which was statistically significant(P < 0.001). The tibiofemoral angle correlated significantly with the Meary angle(P = 0.03) and the talonavicular coverage angle(P = 0.003). ConclusionsPCFD is associated with varus knee malalignment. This varus deformity early in adulthood may lead to deleterious effects like medial compartment osteoarthritis in later life. Early intervention for such patients may help avoid this knee damage. Level of evidenceLevel 3-prognostic.

Influence of the transverse tarsal arch on radiological components of progressive collapsing foot deformity.

The importance of the transverse tarsal arch (TTA) has recently been extensively reevaluated and has even been considered to play a greater role in foot stability than the medial longitudinal arch (MLA). However, the relevance of this observation in the context of common clinical foot disorders, such as progressive collapsing foot deformity (PCFD), has not yet been fully clarified. In this biomechanical study, we examined ten pairs of human cadaveric feet by serial weight-bearing cone-beam computed tomography under controlled loading using a custom-designed testing machine. The MLA and TTA were transected separately, alternating the order in two study groups. A semiautomated three-dimensional evaluation of their influence on three components of PCFD, namely collapse of the longitudinal arch (sagittal Meary's angle), hindfoot alignment (sagittal talocalcaneal angle), and forefoot abduction (axial Meary's angle), was performed. Both arches had a relevant effect on collapse of the longitudinal arch, however the effect of transecting the MLA was stronger compared to the TTA (sagittal Meary's angle, 7.4° (95%CI 3.8° to 11.0°) vs. 3.2° (95%CI 0.5° to 5.9°); p = 0.021). Both arches had an equally pronounced effect on forefoot abduction (axial Meary's angle, 4.6° (95%CI 2.0° to 7.1°) vs. 3.0° (95%CI 0.6° to 5.3°); p = 0.239). Neither arch showed a consistent effect on hindfoot alignment. In conclusion, weakness of the TTA has a decisive influence on radiological components of PCFD, but not greater than that of the MLA. Our findings contribute to a deeper understanding and further development of treatment concepts for flatfoot disorders.

Electromyographic Analysis of Large Muscle Activity in Progressive Collapsing Foot Deformity.

There are various deformities described in the spectrum of Progressive Collapsing Foot Deformity (PCFD) which not only have adverse effects on the foot but also on the entire lower limb. Early lower limb muscular fatigue and pain during exertion is the most common complaint of patients with PCFD. Surface electromyography (sEMG) provides an accurate assessment of muscle activity. In this study, we aim to compare the activities of quadriceps, hamstrings, and gastrosoleus muscle groups of adult patients with PCFD with normal lower limbs and correlate the radiological parameters and functional effects of PCFD with the activities. Thirty patients with bilateral PCFD and 30 controls underwent weight-bearing anteroposterior (AP), lateral, and hindfoot alignment radiographs of the foot. Radiographic parameters of PCFD were assessed. Surface electromyography was used to assess the quadriceps, hamstrings, and gastrosoleus activities, and this was compared between the 2 groups and correlated with radiological measurements of PCFD. Tegner activity questionnaire was used to assess the functional effects of collapsed arch. Electrical activities of all muscle groups were significantly higher in cases than controls. Meary's angle and hindfoot moment arm had significant correlations with hamstring activity (P = .013) and gastrosoleus activity (P = .027), respectively. Tegner scores of cases were significantly lower than those of controls (P = .041). The PCFD causes an increase in activity of large muscles of the affected lower limb which act on joints other than those in the foot. This finding may be due to several compensatory mechanisms that counteract the deforming forces. This may be a cause for the frequent complaint, early fatigue, and hence functional impairment. However, most radiological parameters did not correlate with muscle activities and larger study size may be required for further association. Diagnostic: Level 3.

Correction of progressive collapsing foot deformity classes after isolated arthroscopic subtalar arthrodesis

IntroductionSubtalar osteoarthritis in the context of flatfoot (recently renamed Progressive Collapsing Foot Deformity (PCFD)) may be treated through subtalar joint (SJ) arthrodesis with anticipated consequences on three-dimensional bony configuration. This study investigates the correction of PCFD-related deformities achieved after Anterolateral Arthroscopic Subtalar Arthrodesis (ALAPSTA). MethodsIn this retrospective study, we evaluated pre- and post-operative (at 6 months) weight bearing computed tomography (WBCT) images of patients diagnosed with PCFD with a degenerated SJ (2 A according to PCFD classification) and/or peritalar subluxation (2D) with or without associated flexible midfoot and/or forefoot deformities (1B, 1 C and 1E) which underwent ALAPSTA as a standalone procedure between 2017 and 2020. Multiple measurements were used to assess and compare pre and post-operative PCFD classes. ResultsThirtythree PCFD (33 patients, median age 62) were included in the study. Preoperative medial facet subluxation was 28.3 % (IQR, 15.1 to 49.3 %). Overall PCFD 3D deformity improved with a reduction of the foot and ankle offset from 9.3 points (IQR, 7.8 to 12) to 4 (IQR, 0.9 to 7) (p < 0.001). Class A-hindfoot valgus (median tibiocalcaneal angle and median calcaneal moment arm improved by 9.4 degrees (p < 0.001) and 11 mm (p < 0.001), respectively), class B-midfoot abduction (median talonavicular coverage angle improved by 20.5 degrees, p < 0.001) and class C-forefoot varus (median sagittal talo-first metatarsal angle improved by 10.2 degrees (p < 0.001)) were significantly corrected after surgery. Class D was difficult to assess due to the fusion procedure. No patient had a pre-operative valgus deformity at the ankle (no class E), and no significant change of the talar tilt was observed (p = 0.12). ConclusionIn this series, ALAPSTA performed as a standalone procedure to treat patients diagnosed with PCFD with a degenerated subtalar joint and/or peritalar subluxation was effective not only at correcting hindfoot alignment but also flexible midfoot abduction and flexible forefoot varus. Level of evidenceLevel IV, case series

Flatfoot Surgery for Flexible Progressive Collapsing Foot Deformity With Inflammatory Joint Diseases: A Report of 3 Cases.

Three cases of inflammatory joint diseases (systemic lupus erythematosus and ongoing juvenile idiopathic arthritis) with painful flexible progressive collapsing foot deformity (PCFD) underwent flatfoot surgery. All cases maintained sufficient radiological correction and achieved good clinical condition at final follow-up. Although the prospect for recurrence of the deformity is not clear, even in inflammatory joint diseases, flat foot surgery such as flexor digitorum longs transfer, spring ligament reconstruction, and lateral column lengthening could have a possibility to be indicated against PCFD, as long as disease activity could be well suppressed by drug therapy, subsequently subtalar and talonavicular joints could be preserved.

Clinical outcomes of subtalar arthroereisis for the treatment of stage 1 flexible progressive collapsing foot deformity

BackgroundThe use of subtalar arthroereisis as an adjunct to the surgical treatment of stage 1 flexible progressive collapsing foot deformity (PCFD) is controversial. The aim was to investigate the clinical outcomes and report the implant removal rate of subtalar arthroereisis as an adjunct for stage 1 PCFD.MethodsA retrospective study of 212 consecutive feet undergoing operative management of stage 1 PCFD with adjunctive subtalar arthroereisis between October 2010 and April 2018. The primary outcome was the Foot and Ankle Outcome Score (FAOS). Secondary outcomes included Foot and Ankle Disability Index (FADI), Euroqol-5D-5L Index and implant removal rate.ResultsPost-operative clinical FAOS outcomes were collected for 153 feet (72.2%). At mean 2.5-year follow-up, the mean ± standard deviation FAOS for each domain was as follows; Pain: 81.5 ± 18.5, Symptoms: 79.5 ± 12.9, Activities of Daily Living: 82.5 ± 15.4 and Quality of Life: 64.2 ± 23.7. EQ-5D-5L Index was 0.884 ± 0.152. Pre-operative scores were available for 20 of these feet demonstrating a statistically significant improvement in all FAOS, FADI and EQ-5D-5L domains (p < 0.05). The implant removal rate for persistent sinus tarsi pain was 48.1% (n = 102).ConclusionUse of a subtalar arthroereisis implant as an adjunct to conventional procedures in stage 1 flexible PCFD can result in significant improvement in pain and function. Patients should be counselled as to the relatively frequent rate of subsequent implant removal.Level of evidenceIV.

Progressive collapsing foot deformity: how to use new knowledge in developing countries

The 2019 progressive collapsing foot deformity (PCFD) consensus did not only change the disease nomenclature and provided a new classification for the condition formerly known as flatfoot deformity. It was also the pinnacle of a revolution in the field in terms of knowledge and clinical perspectives. The use of advanced imaging, such as weight-bearing computed tomography, three-dimensional algorithms, and magnetic resonance, expanded the way we understand peritalar subluxation and how we can address it. However,much of these improvements felt short in terms of global reproducibility due to economic restraints. The objective of this review studyis to present PCFD new concepts through the lens and realities of developing countries, considering their potentially limited access tonovel technologies. Level of Evidence V; Expert opinion.

Risk Factors for Midfoot Arthritis Associated With Medical History by Weight Bearing Computed Tomography

Tarso-metatarsal joints and naviculocuneiform joints comprising midfoot is the second most commonly involved joints following the first metatarsophalangeal joint in the foot. However, related factors of midfoot arthritis (MA) have been rarely reported. The bony structure and alignment can be more precisely assessed using Weight-Bearing Computed Tomography (WBCT) than conventional radiographs. Therefore, the aim of this study was to investigate risk factors for MA related to medical history and comorbid foot deformities using WBCT. WBCT data from September 2014 to April 2022 were extracted from a single referral hospital. All cases were divided into two groups by the presence of MA. Twenty-five potential related factors including demographics, etiology, and common co-occurring foot deformities were collected for comparison. Six hundred six cases (247 males and 359 females) among consecutive 1316 cases between September 2014 to April 2022 were selected. One hundred thirty-nine male cases (56.3%) and 210 female cases (58.5%) showed MA. In stepwise multiple logistic regression analysis, 5 factors remained statistically significant. The multivariate-adjusted odds ratios for age, laterality, body mass index (BMI), Progressive Collapsing Foot Deformity (PCFD), and lesser toe deformities (LTD) were 1.08, 1.54, 1.05, 6.62, and 3.03 respectively. Risk factors for MA associated with medical history and foot deformities included age, laterality, BMI, PCFD, and LDT.

Defining the Patient Acceptable Symptom State Using PROMIS Following Reconstruction of the Progressive Collapsing Foot Deformity

Introduction/Purpose: Although reconstruction of the flexible progressive collapsing foot deformity (PCFD) has been shown to improve patient-reported outcomes (PROs), there is limited data describing postoperative success as defined by patient satisfaction following surgery. Distinct from the minimal clinically important difference (MCID), the patient acceptable symptom state (PASS) is a novel PRO measurement that represents the symptom threshold beyond which patients are satisfied with their postoperative outcome. The primary aim of this study was to use Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function (PF) and Pain Interference (PI) scores in combination with anchor questions to define PASS thresholds following reconstruction of the flexible PCFD. A secondary aim was to analyze how patient-specific variables and certain PCFD reconstruction procedures may impact the probability of reaching PASS thresholds. Methods: Using data collected from a foot and ankle orthopedic registry at a large academic institution, 109 patients who underwent reconstruction of a flexible PCFD between February 2019 and March 2021, had preoperative and 2-year postoperative PROMIS PF and PI scores, and 2-year postoperative responses to two PASS anchor questions (the delighted-terrible scale and the satisfied scale) were included in the study. Patients who underwent either a double or triple arthrodesis were excluded. Patient responses to the anchor questions were dichotomized and receiver operating characteristic (ROC) curve analyses were performed. Using the Youden Index to balance sensitivity and specificity and maximize the area under the curve (AUC), PASS thresholds with 95% confidence intervals were quantified using 2000 bootstrapped iterations. Lastly, multivariable logistic regressions were performed to analyze the influence of patient demographics, preoperative PROMIS scores, and certain PCFD reconstruction procedures on the probability of reaching the PASS thresholds. Results: The PASS threshold for PROMIS PF was found to be 42.6 using both the delighted-terrible and the satisfied scale and 73.4% of patients (80/109) reached the threshold (both AUCs: 0.91) (Table 1). The PASS thresholds for PROMIS PI defined using the delighted-terrible scale and the satisfied scale were 54.5 (AUC: 0.90) and 57.5 (AUC: 0.91), respectively, with 72.5% of patients (79/109) and 81.7% of patients (89/109) meeting the respective thresholds. Neither patient demographics nor specific PCFD reconstruction procedures affected the probability of meeting the PASS thresholds. However, a lower preoperative PROMIS PF score or a higher preoperative PROMIS PI score significantly decreased the probability of achieving the PASS thresholds. Conclusion: Following reconstruction of the flexible PCFD, PASS thresholds for the PROMIS PF and PI domains were found to be lower and higher, respectively, than population norms. This suggests that patients may be satisfied with the outcome of their surgery despite not returning to the population mean. The probability of achieving the PASS thresholds was influenced by both preoperative PROMIS PF and PI scores but not by patient demographics or certain PCFD reconstruction procedures. In addition to guiding future outcomes research, these results may help foot and ankle surgeons optimize treatment for the flexible PCFD and better manage patient expectations.

First Tarsometatarsal Instability Corrects Itself After Triple Arthrodesis in Progressive Collapsing Foot Deformity

Introduction/Purpose: Triple arthrodesis is commonly used to correct severe or rigid progressive collapsing foot deformity (PCFD). In many cases of PCFD, patients have associated first tarsometatarsal instability demonstrated by plantar gapping or dorsal subluxation on the lateral weight-bearing radiographs. During flatfoot reconstruction this is usually addressed with a first tarsometatarsal fusion to realign the joint and to restore the medial column height. However in the setting of triple arthrodesis it has not been well established if it is necessary to add a first tarsometatarsal fusion to the procedure in order to adequately correct the overall deformity. This study retrospectively examined pre- and post-operative radiographs of patients that had first tarsometatarsal instability as a component of their PCFD and who were managed by triple arthrodesis alone. Methods: All triple arthrodesis cases were searched for a single surgeon between 2013 and 2021. Inclusion criteria were patients who had a diagnosis of PCFD and had an isolated triple arthrodesis without first tarsometatarsal joint fusion. Pre-operative radiographs were then examined for the presence of first tarsometatarsal joint instability on the lateral weight-bearing view only. This was demonstrated by either plantar gapping or first metatarsal dorsal subluxation at the tarsometatarsal joint. Those patients who were a minimum of 21 months post-op were called to obtain current radiographs. Measurement of the sagittal first metatarsal-medial cuneiform angle as well as a the first metatarsal lift as described by King and Toolan (FAI 2004) was performed. Results: Twenty patients satisfied the inclusion criteria and were included in the study. Of these patients, five had no correction of their first tarsometatarsal joint instability postoperatively and were considered failures. The remaining fifteen patients demonstrated early correction of their first tarsometatarsal joint instability and were called back for longer term follow-up radiographs. Average follow-up was 4.8 years (range 1.8 - 9.4 years). The sagittal first metatarsal-medial cuneiform angle (plantar gapping) improved significantly from 3.8 degrees to 1.0 degrees (p=0.00002). The first metatarsal lift (dorsal subluxation) corrected from 4.0 mm to 1.5 mm (p=0.000001). Only one patient showed radiographic evidence of arthritis in the first tarsometatarsal joint at final follow-up. Conclusion: First tarsometatarsal joint fusion to correct medial column instability is well established in flatfoot reconstruction cases. However less is known about whether this is required when performing a triple arthrodesis for PCFD. In this study, 75% of patients had their first tarsometatarsal joint instability correct itself after isolated triple arthrodesis and maintained this correction at 4.8 year follow-up. In many cases of PCFD with medial column instability, triple arthrodesis alone may be adequate to restore overall alignment thereby avoiding the additional operative time and risk for complication associated with a first tarsometatarsal joint fusion. First tarsometatarsal joint instability correction following isolated triple arthrodesis. Pre-operative radiographs demonstrate plantar gapping and dorsal subluxation at the first tarsometatarsal joint consistent with medial column instability. At 2.8 year post-operative follow up after isolated triple arthrodesis, radiographs show maintained correction of the instability.

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

BackgroundThe 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. MethodsThis 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. ResultsPASS 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. ConclusionIn addition to guiding future outcomes research, these results may help surgeons optimize treatment for PCFD and better manage patient expectations. Level of evidenceIII, retrospective cohort study

Peroneus Brevis to Longus Tendon Transfer in the Treatment of Flexible Progressive Collapsing Foot Deformity: A Cadaveric Study.

Although operative treatment of the flexible progressive collapsing foot deformity (PCFD) remains controversial, correction of residual forefoot varus and stabilization of the medial column are important components of reconstruction. A peroneus brevis (PB) to peroneus longus (PL) tendon transfer has been proposed to address these deformities. The aim of our study was to determine the effect of an isolated PB-to-PL transfer on medial column kinematics and plantar pressures in a simulated PCFD (sPCFD) cadaveric model. The stance phase of level walking was simulated in 10 midtibia cadaveric specimens using a validated 6-degree of freedom robot. Bone motions and plantar pressure were collected in 3 conditions: intact, sPCFD, and after PB-to-PL transfer. The PB-to-PL transfer was performed by transecting the PB and advancing the proximal stump 1 cm into the PL. Outcome measures included the change in joint rotation of the talonavicular, first naviculocuneiform, and first tarsometatarsal joints between conditions. Plantar pressure outcome measures included the maximum force, peak pressure under the first metatarsal, and the lateral-to-medial forefoot average pressure ratio. Compared to the sPCFD condition, the PB-to-PL transfer resulted in significant increases in talonavicular plantarflexion and adduction of 68% and 72%, respectively, during simulated late stance phase. Talonavicular eversion also decreased in simulated late stance by 53%. Relative to the sPCFD condition, the PB-to-PL transfer also resulted in a 17% increase (P = .045) in maximum force and a 45-kPa increase (P = .038) in peak pressure under the first metatarsal, along with a medial shift in forefoot pressure. The results from this cadaver-based simulation suggest that the addition of a PB-to-PL transfer as part of the surgical management of the flexible PCFD may aid in correction of deformity and increase the plantarflexion force under the first metatarsal. This study provides biomechanical evidence to support the addition of a PB-to-PL tendon transfer in the surgical treatment of flexible PCFD.

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

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. 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. 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. 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. 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.

Radiographic Analysis of Valgus Ankle Deformity With or Without Medial Longitudinal Arch Collapse.

Establishing a surgical plan for ankle deformities necessitates a comprehensive understanding of the deforming forces involved, and the morphology of the ankle deformity plays an important role as well. Valgus tibiotalar tilt development has mostly been described in patients with a low medial longitudinal arch, as seen in progressive collapsing foot deformity (PCFD). However, some valgus ankles demonstrate no radiographic evidence of a collapsed medial arch. This study aims to investigate whether there are differences in the radiographic morphology of valgus ankle deformities between patients with and without a low medial longitudinal arch to explore if they have different etiologies. We retrospectively reviewed patients who underwent surgical treatment for asymmetric valgus ankle deformity at our institution between 2017 and 2021. Patients with a valgus tibiotalar tilt (TT) greater than 4 degrees and Meary angle greater than 30 degrees (mean: 38.9) were included in the PCFD group (n = 29). The non-PCFD group (n = 24) with TT greater than 4 degrees and Meary angle less than 4 degrees (mean: 0.3) was also established. In the weightbearing ankle anteroposterior view, the TT and medial distal tibial angle were measured. Additionally, to assess the mediolateral position of the talus, the talar center migration (TCM) and lateral talar dome-plafond distance (LTD-P) ratio in the coronal plane were measured. In weightbearing computed tomography (WBCT), the degree of axial plane talocalcaneal subluxation and the prevalence of sinus tarsi bony impingement were assessed. Intergroup comparison was conducted. Both groups demonstrated a similar degree of TT, with a mean of 11.6 degrees in the PCFD group and 13.7 degrees in the non-PCFD group (P = .2330). However, the PCFD group showed a significantly greater TCM and LTD-P ratio compared with those of the non-PCFD group (P < .0001), indicating that PCFD patients have a more medially translated talus in ankle anteroposterior radiographs. WBCT showed that the PCFD group on average had 18 degrees greater axial plane talocalcaneal subluxation (P < .0001) and 52% higher prevalence of sinus tarsi bony impingement (P = .0002) compared with the non-PCFD group. This study suggests that valgus ankles may exhibit different radiographic morphologies depending on the status of the longitudinal arch. Valgus ankles in PCFD patients tend to have a more medially translated talus. This finding may suggest the presence of different deforming forces between the 2 groups and may indicate the need for different treatment strategies to address talar tilt. Level III, case-control.

Association Between Weightbearing CT and MRI Findings in Progressive Collapsing Foot Deformity.

Weightbearing computed tomography (WBCT) scans allow for a better understanding of foot alignment in patients suffering from progressive collapsing foot deformity (PCFD). However, soft tissue integrity (eg, spring ligament complex or tibialis posterior tendon) cannot be easily assessed via WBCT. As performing both WBCT and magnetic resonance imaging (MRI) might not be cost effective, we aimed to assess whether there is an association between osseous and soft tissue findings in WBCT and MRI. In this observational study, a consecutive cohort of 24 patients of various stages of PCFD (mean age 51 ± 18 years) underwent WBCT scans and MRI. Twenty-four healthy individuals of similar age, body mass index (BMI), and sex with WBCT scans were used as a control group. In addition to of osseous sinus tarsi impingement, 4 commonly used 3-dimensional (3D) measurements (talocalcaneal overlap [TCO], talonavicular coverage [TNC], Meary angle [MA], axial/lateral) were obtained using a dedicated postprocessing software (DISIOR 2.1, Finland) on the WBCT data sets. Sinus tarsi obliteration, spring ligament complex, tibiospring ligament integrity, as well as tibialis posterior tendon degeneration were evaluated with MRI. Statistical analysis was performed for significant (P < .05) correlation between findings. None of the assessed 3D measurements correlated with either spring ligament complex or tibiospring ligament tears. BMI and TCO were found to be associated with tibialis posterior tendon tears. Seventy-five percent of patients with osseous sinus tarsi impingement on WBCT also showed signs of sinus tarsi obliteration on MRI. Although WBCT reflects foot alignment and can reveal osseous sinus tarsi impingement in PCFD patients, the association between WBCT-based 3D measurements and ligament or tendon tears assessed via MRI is limited. WBCT appears complimentary to MRI regarding its diagnostic value. Both imaging options add important information and may impact decision making in the treatment of PCFD patients. Level IV, observational study.

Biomechanical Effects of Subtalar Joint Fusion and Medial Ligament Reconstruction in Simulated Progressive Collapsing Foot Deformity.

The purpose of this study is to investigate the biomechanical effect of medial displacement calcaneal osteotomy (MDCO), subtalar joint fusion (SF), and medial ligament reconstruction (MLR: deltoid-spring ligament) in a severe flatfoot model. We hypothesized that (1) combination of MDCO and SF improves the tibiotalar and foot alignment in severe progressive collapsing foot deformity (PCFD) cadaver model. (2) However, if a residual valgus heel alignment remains after MCDO and SF, it can lead to increased medial ligament strain, foot malalignment, and tibiotalar valgus tilt, which will be mitigated by the addition of MLR. Ten fresh-frozen cadaveric foot specimens were used to create a severe flatfoot model. The foot alignment changes, including the talo-first metatarsal angle in the axial and sagittal planes, subtalar angle, and tibiotalar angle in the coronal plane, were measured. The angles were measured at the initial condition, after creating the severe flatfoot model, and after each successive reconstructive procedure in the following order: (1) MDCO, (2) SF, and (3) MLR. Tibiotalar valgus tilt was decreased with the MDCO procedure: 4.4 vs 1.0 degrees (P = .04). Adding in situ SF to the MDCO led to increased tibiotalar tilt to 2.5 degrees was different from the initial condition (P = .01). Although the tibiotalar valgus tilt was significantly decreased after adding the MLR to the MDCO/SF procedure compared with the severe flatfoot model (0.8 vs 4.4 degrees, P = .03), no significant difference in the tibiotalar valgus tilt was observed between MDCO/SF and MDCO/SF with MLR. Our results demonstrated that MDCO significantly improved forefoot abduction and medial arch alignment, with no significant additional improvement observed with addition of SF. Following SF, a residual valgus heel alignment can contribute to subsequent tibiotalar valgus tilt. The addition of MLR did not show significantly decreased tibiotalar valgus tilt following SF. Residual valgus heel alignment after subtalar joint fusion in the surgical treatment of PCFD can lead to increased medial ligament strain. Although MLR might be considered for providing medial stability, it may not necessarily prevent the development of tibiotalar valgus tilt.

Minimally Invasive Scarf Calcaneal Osteotomy is an Alternative Technique for the Correction of Progressive Collapsing Foot Deformity

Scarf calcaneal osteotomy is an extra-articular procedure to correct progressive collapsing foot deformity (PCFD). As an open approach may display wound healing problems, we herein report a novel method of percutaneously performed minimally invasive scarf calcaneal osteotomy. Twenty patients aged 56.75 ± 7.13 with grade 1AB of PCFD were included. A radiologic assessment was performed before the procedure and after 3 months. Clinical evaluation was done before the procedure, after 3 months, and after 12 months. The Manchester-Oxford Foot Questionnaire and Functional Foot Index score improved from 77.63 ± 11.67 preoperatively to 33.29 ± 18.55 at the follow-up (P &lt; 0.001) and from 69.26 ± 16.32 preoperatively to 32.00 ± 20.35 at the follow-up (P &lt; 0.001), respectively. There was a statistically significant improvement in all radiologic measurements, namely, talonavicular coverage angle from 20.03 ± 5.51 to 14.18 ± 6.49 (P &lt; 0.001), the distance between medial cuneiform and fifth metatarsal from 0.53 ± 3.31 to 6.95 ± 4.01 (P &lt; 0.001), anteroposterior talo-first metatarsal angle from 22.13 ± 7.28 to 17.09 ± 6.87 (P &lt; 0.005), Meary angle from 25.12 ± 2.73 to 15.17 ± 7.06 (P &lt; 0.001), calcaneal inclination angle from 12.23 ± 4.01 to 16.82 ± 5.53 (P &lt; 0.001), navicular height from 15.57 ± 4.10 to 20.57 ± 6.87 (P &lt; 0.005), and tibio-calcaneal angle from −3.79 ± 5.15 to 6.71 ± 4.41 (P &lt; 0.001). In experienced hands, minimally invasive scarf calcaneal osteotomy seems to be an effective and reproducible subtalar preserving surgical technique for PCFD cases with mild midfoot abduction severity. Level of Evidence: Diagnostic Level 4. See Instructions for Authors for a complete description of levels of evidence.

ALTERNATION OF THE 3D SUBTALAR JOINT ALIGNMENT AFTER INFRAMALLEOLAR OSTEOTOMY IN PROGRESSIVE COLLAPSING FLATFOOT DEFORMITY

A medializing calcaneal osteotomy (MCO) is one of the key inframalleolar osteotomies to correct progressive collapsing foot deformity (PCFD). While many studies were able to determine the hind- and midfoot alignment after PCFD correction, the subtalar joint remained obscured by superposition on plain radiography. Therefore, we aimed to perform a 3D measurement assessment of the hind- and subtalar joint alignment pre- compared to post-operatively using weightbearing CT (WBCT) imaging.Fifteen patients with a mean age of 44,3 years (range 17-65yrs) were retrospectively analyzed in a pre-post study design. Inclusion criteria consisted of PCFD deformity correct by MCO and imaged by WBCT. Exclusion criteria were patients who had concomitant midfoot fusions or hindfoot coalitions. Image data were used to generate 3D models and compute the hindfoot - and talocalcaneal angle as well as distance maps.Pre-operative radiographic parameters of the hindfoot and subtalar joint alignment improved significantly relative to the post-operative position (HA, MASa, and MACo). The post-operative talus showed significant inversion, abduction, and dorsiflexion of the talus (2.79° ±1.72, 1.32° ±1.98, 2.11°±1.47) compared to the pre-operative position. The talus shifted significantly different from 0 in the posterior and superior direction (0.62mm ±0.52 and 0.35mm ±0.32). The distance between the talus and calcaneum at the sinus tarsi increased significantly (0.64mm ±0.44).This study found pre-dominantly changes in the sagittal, axial and coronal plane alignment of the subtalar joint, which corresponded to a decompression of the sinus tarsi. These findings demonstrate the amount of alternation in the subtalar joint alignment that can be expected after MCO. However, further studies are needed to determine at what stage a calcaneal lengthening osteotomy or corrective arthrodesis is indicated to obtain a higher degree of subtalar joint alignment correction.