Progressive Collapsing Foot 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.

Trends in the Use of Weightbearing Computed Tomography.

Background: This review aimed to critically appraise the most recent orthopedic literature around cone beam weightbearing computed tomography (WBCT), summarizing what evidence has been provided so far and identifying the main research trends in the area. Methods: This scoping review was performed on studies published between January 2013 and December 2023 on the Pubmed database. All studies (both clinical and nonclinical) in which WBCT had been used were critically analyzed to extract the aim (or aims) of the study, and the main findings related to the role of this imaging modality in the diagnostic pathway. Results: Out of 1759 studies, 129 were selected. One hundred five manuscripts (81%) dealt with elective orthopedic conditions. The majority of the analyses (88 studies; 84%) were performed on foot and ankle conditions, while 13 (12%) studies looked at knee pathologies. There was a progressive increase in the number of studies published over the years. Progressive Collapsing Foot Deformity (22 studies; 25%) and Hallux Valgus (19 studies; 21%) were frequent subjects. Twenty-four (19%) manuscripts dealt with traumatic conditions. A particular interest in syndesmotic injuries was documented (12 studies; 60%). Conclusions: In this review, we documented an increasing interest in clinical applications of weightbearing CT in the orthopedic field between 2013 and 2023. The majority of the analyses focused on conditions related to the foot and the ankle; however, we found several works investigating the value of WBCT on other joints (in particular, the knee).

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.

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.

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.

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

ASSOCIATION BETWEEN WEIGHTBEARING CT AND MRI FINDINGS IN PROGRESSIVE COLLAPSING FOOT DEFORMITY

BackgroundWeightbearing computed tomography scans allow for better understanding of foot alignment in patients with Progressive Collapsing Foot Deformity. However, soft tissue integrity cannot be assessed via WBCT. As performing both WBCT and magnetic resonance imaging is not cost effective, we aimed to assess whether there is an association between specific WBCT and MRI findings.MethodsA cohort of 24 patients of various stages of PCFD (mean age 51±18 years) underwent WBCT scans and MRI. In addition to signs of sinus tarsi impingement, four three-dimensional measurements (talo-calcaneal overlap, talo-navicular coverage, Meary's angle axial/lateral) were obtained using a post processing software (DISIOR 2.1, Finland) on the WBCT datasets. Sinus tarsi obliteration, spring ligament complex and tibiospring ligament integrity, as well as tibialis posterior tendon degeneration were evaluated with MRI. Statistical analysis was performed for significant (P&lt;0.05) correlation between findings.ResultsNone of the assessed 3D measurements correlated with spring ligament complex or tibiospring ligament tears. Age, body mass index, and TCO were associated with tibialis posterior tendon tears. 75% of patients with sinus tarsi impingement on WBCT also showed signs of sinus tarsi obliteration on MRI. Of the assessed parameters, only age and BMI were associated with sinus tarsi obliteration diagnosed on MRI, while the assessed WBCT based 3D measurements were, with the exception of MA axial, associated with sinus tarsi impingement.ConclusionWhile WBCT reflects foot alignment and indicates signs of osseous impingement in PCFD patients, the association between WBCT based 3D measurements and ligament or tendon tears in MRI is limited. Partial or complete tears of the tibialis posterior tendon were only detectable in comparably older and overweight PCFD patients with an increased TCO. WBCT does not replace MRI in diagnostic value. Both imaging options add important information and may impact decision-making in the treatment of PCFD patients.

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.

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

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.

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.

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.

Isolated Talonavicular Arthrodesis as Treatment for Flexible Progressive Collapsing Foot Deformity: A Case Series.

For the younger, more active patient with flexible symptomatic progressive collapsing foot deformity (PCFD), joint-sparing procedures may be preferred to preserve functional motion. Isolated talonavicular (TN) arthrodesis has been described for treatment of rigid and flexible PCFD for patients that are older and less active whose deformity is still correctable through the TN joint. The purpose of this study was to evaluate radiographic and clinical outcomes in patients with PCFD treated with isolated triplanar correction with a TN joint arthrodesis. Forty-nine patients (53 feet) with flexible PCFD underwent isolated TN arthrodesis. Weightbearing radiographs were performed pre- and postoperatively, and measurements included lateral talar-first metatarsal angle, calcaneal pitch, TN coverage angle, and the anteroposterior (AP) talar-first metatarsal angle. The Foot and Ankle Ability Measure (FAAM) and Veterans-Rand 12-Item Health Survey (VR-12) scores were also collected. Thirty-five females and 14 males were evaluated with a mean age of 63 years, at an average follow-up of 41.3 months. Significant improvements were found radiographically. Lateral radiographs demonstrated improvements in lateral talar-first metatarsal angle from 25.2 degrees preoperatively to 9.5 degrees postoperatively (P < .001) and calcaneal pitch from 14.9 degrees preoperatively to 17.5 degrees postoperatively (P < .001). AP radiographs showed the TN coverage angle improving from 35.0 degrees to 4.9 degrees postoperatively (P < .001) and AP talar-first metatarsal angle improving from 17.3 degrees to 5.9 degrees postoperatively (P < .001). Clinical outcomes were improved in the FAAM pain score (48.6 to 39.2, P = .130), FAAM ADL score (53.8 to 69.2, P = .002), FAAM Sport score (29.5 to 40.7, P = .099), and the overall FAAM score (47.7 to 63.1, P = .006). Patient satisfaction with medical care was 85.2/100 postoperatively. Isolated TN arthrodesis is a viable surgical option for older, lower-demand patients with flexible PCFD. This study demonstrated significant improvements in radiographic alignment and FAAM scores. Comparative studies with other surgical procedures should be performed to determine which is the best technique for older, lower-demand patients with flexible PCFD. Level III, retrospective cohort study.

The Mini Bone Extra-articular Reconstruction System for Progressive Collapsing Foot Deformity—Surgical Technique With Cadaveric Quantification of Surrounding Anatomy

We present a novel surgical technique, the mini Bone Extra-articular Reconstruction (BEAR) system, that involves minimally invasive all BEAR systems. The surgical technique was used to perform the medial displacement calcaneal osteotomy, Evans osteotomy, and Cotton osteotomy on 9 cadaveric feet under fluoroscopic guidance. We also present a case series of patients who have undergone the procedure. We first carefully dissected the sural nerve, superficial peroneal nerve, and its branches from each cadaveric foot and evaluated injuries following the mini-BEAR osteotomy cuts. We then measured and recorded the distance between the osteotomy cuts and these anatomic structures. We believe that this technique can potentially replace the multiple long surgical incisions with minimal ones. Level of Evidence: Level IV.

The Role of the Transverse Arch in Progressive Collapsing Foot Deformity.

The transverse arch (TA) has recently been shown to significantly increase the intrinsic stiffness of the midfoot when coupled with the medial longitudinal arch (MLA). Progressive collapsing foot deformity (PCFD) is a complex deformity that ultimately results in a loss of stiffness and collapse of the MLA. The role of the TA has not been investigated in patients diagnosed with this disorder using weightbearing CT (WBCT). Therefore, this study aims to answer the following questions: (1) Is the curvature of the TA decreased in PCFD? (2) Where within the midfoot does TA curvature flattening happen in PCFD? A retrospective review of weightbearing CT images was conducted for 32 PCFD and 32 control feet. The TA curvature was assessed both indirectly using previously described methods and directly using a novel measurement termed the transverse arch plantar (TAP) angle that assesses the angle formed between the first, second, and fifth metatarsals in the coronal plane. Location of TA collapse was also assessed in the coronal plane. The TAP angle was significantly higher in PCFD (mean 115.2 degrees, SD 10.7) than in the control group (mean 100.8 degrees, SD 7.9) (P < .001). No difference was found using the calculated normalized TA curvature between PCFD (mean 17.1, SD 4.8) and controls (mean 18.3, SD 4.0) (P = .266). Location of collapse along the TA in PCFD was most significant at the second metatarsal and medial cuneiform. The TA is more collapsed in PCFD compared to controls. This collapse was most substantial between the plantar medial cuneiform and the plantar second metatarsal. This may represent a location of uncoupling of the TA and MLA. Level III, retrospective case control.

Transfer of the Flexor Hallucis Longus Tendon Improves Joint Kinematics of the Medial Column during Simulated Stance Phase in Progressive Collapsing Foot Deformity

Category: Hindfoot; Midfoot/Forefoot Introduction/Purpose: Medial longitudinal arch collapse is one of the key clinical and radiographic features of progressive collapsing foot deformity (PCFD) and can occur anywhere within its three constituents: first tarsometatarsal (TMT1), naviculo- cuneiform (NC), and talonavicular (TN) joints. Medial column osteotomy or fusion has typically been utilized to address this instability. A new procedure involving transferring the flexor hallucis longus (FHL) tendon to the 1st metatarsal base has shown promising results in restoring radiographic alignment of the entire medial column in conjunction with a hindfoot procedure. However, the mechanism of correction in a dynamic environment is unclear. Thus, this study examined the effect of medial column stabilization using FHL transfer on the foot and ankle kinematics during stance phase. Methods: Twelve mid-tibia cadaveric specimen (6 male; Age 48 ± 16 years) underwent stance phase simulations using a validated six-degree of freedom robotic gait simulator. Three conditions were tested each cadaveric specimen: pre-deformity (Intact), after creating a simulated progressive collapsing foot deformity (sPCFD), and after an FHL transfer (FHL). Motion capture cameras tracked the motion of retroreflective markers inserted into bones of the foot and ankle. The FHL transfer was performed on each specimen by harvesting the FHL tendon at its distal insertion and fixing it in the 1st metatarsal with a biotenodesis screw (Figure 1A). Outcome measures include joint rotations of the TMT1, NC, TN, subtalar, and ankle joint. Significant differences (p &lt; 0.05) in joint kinematics were statistically analyzed by constructing 95% confidence intervals of the repeated measures difference between both the sPCFD and FHL conditions and the intact condition. Results: The FHL condition demonstrated significant differences in the kinematics of the medial column compared to the sPCFD condition (Figure 1B). The TMT1 joint showed increased plantarflexion in early and late stance, as well as increased eversion during early and mid-stance. The NC joint demonstrated increased plantarflexion, eversion, and abduction during early stance. At the TN joint, there was increased inversion during early and late stance, as well as increased adduction during mid-stance. At the subtalar joint, subtalar eversion was decreased during early stance, and no significant differences were observed from the intact condition throughout stance. No differences were found in the ankle joint kinematics across all conditions. Conclusion: The results of our study demonstrate that the medial column stabilization procedure with FHL transfer can improve the kinematics of the medial column in sPCFD. Additionally, the correction at the TN and subtalar joint demonstrates the potential efficacy of this procedure for hindfoot correction. The correction occurred during the earlier stance phase as well when the FHL is not active, suggesting that this procedure provides correction in both a dynamic and static manner. This procedure can be used in conjunction with hindfoot corrective procedures in PCFD, particularly when preoperative imaging suggests multiple levels of instability within the medial column.