Non-surgical management of posterior tibial tendon dysfunction- a UK survey.

BACKGROUND: Posterior Tibial Tendon Dysfunction (PTTD) is commonly seen within musculoskeletal care. The condition's prevalence and management is poorly understood. This study aims to demonstrate current practice by multi-professional clinicians across the United Kingdom within the National Health Service. METHODS: A national (UK) cross-sectional online survey was conducted among multi-professionals who treat PTTD within their NHS practice. The survey covered assessment, management and evaluation. This was shared via social media and professional groups. RESULTS: Two hundred thirteen surveys were completed, with 153 matching the eligibility criteria. The main respondents were Physiotherapists (48%) and Podiatrists (38%). Ultrasound scanning was used most frequently when considering initial imaging (67%). Many different treatment modalities were used, but a core set of education/advice, foot orthoses, and foot specific as well as general exercise were most commonly chosen. Outcome measures routinely used were pain scale (96/269) and single leg heel raise (84/269), but patient reported outcome measures were not routinely used. The most frequent reason to escalate care was failure to manage symptoms with conservative management (106/123; 86.2%), followed by fixed deformity (10/123; 8.2%). CONCLUSIONS: This survey provides evidence on current non-surgical management for PTTD from UK NHS practice. It provides a valuable marker for clinicians to use to compare their own practice and can be used in further research as a comparator.

Lower limbs biomechanical deficits associated with stage 1 and 2 posterior tibialis tendon dysfunction during walking.

BACKGROUND: Posterior tibialis tendon dysfunction (PTTD) is a chronic degenerative musculoskeletal disorder causing a progressive ankle complex and arch collapse altering lower limb biomechanics. However, biomechanical changes associated with stage 1 and 2 PTTD need to be better characterized during walking to guide clinical recommendations and improve non-operative treatments. RESEARCH QUESTION: What are the lower limb kinematic and kinetic differences between individuals with stage 1 (PTTD1), individuals with stage 2 PTTD (PTTD2) and healthy counterparts during gait? METHODS: Sixteen PTTD1, 11 PTTD2 and 20 healthy controls were included in this multicentric case-control study to compare their lower limb gait biomechanics. Kinematic and kinetic data were recorded using a three-dimensional motion capture system and a force plate. One-dimensional statistical parametric mapping was used to compare lower limb joint motion and moments between groups during the stance phase. RESULTS: PTTD1 had minimal biomechanical differences compared with the control group. In contrast, PTTD2 presented significant differences compared with controls and PTTD1. At the ankle, PTTD2 exhibited greater plantarflexion and eversion angles and midfoot dorsiflexion and inversion angles throughout stance compared with controls and PTTD1. PTTD2 presented lower midfoot abduction moments compared with controls. These changes led PTTD2 to exhibit knee and hip adaptative biomechanical mechanisms in the frontal and transverse planes in late stance. PTTD2 had greater knee internal rotation angles and smaller knee external rotation moments compared to controls. PTTD2 had smaller hip internal rotation angles compared with PTTD1 and smaller hip adduction moments compared with controls. SIGNIFICANCE: PTTD1 showed minimal biomechanical differences compared to controls and important differences compared to PTTD2. The lower limb biomechanical deficits accentuate as the pathology advances from stage 1 to stage 2. PTTD is a progressive condition needing early clinical management at stage 1 to avoid successive biomechanical changes associated with stage 2.

"Biological Fixation" of Flexor Digitorum Longus: A New Modification of Tendon Transfer for Treatment of Posterior Tibialis Tendon Dysfunction.

Numerous surgical procedures for the treatment of posterior tibialis tendon (PTT) dysfunction have been developed, including tendon transfers, osteotomies, and arthrodesis. Among these methods, foot and ankle surgeons most frequently use flexor digitorum longus (FDL) tendon transfer in conjunction with medial translational osteotomy of the calcaneus. Formerly, some less invasive techniques have been described to reduce surgical-related complications after FDL tendon transfer. Herein, we introduced a new modification of short-stump FDL tendon fixation to the navicular bone and reported the functional outcomes of the current technique in a patient with PTT dysfunction. In the current technique, the FDL tendon was fixed to the navicular bone via a trans-osseous tunnel using a split PTT stump. This method does not require any kind of fixation devices, such as an interference screw or anchor suture.Level of Evidence: V.

Endoscopic assisted flexor digitorum longus transfer in flexible flatfoot.

BACKGROUND: Posterior tibial tendon insufficiency is the commonest cause of adult flexible flatfoot. Transfer of the flexor digitorum longus (FDL) has been described a therapeutic arsenal in flexible flat feet and posterior tibial tendon disorders. It is often combined with bony procedure (open or percutaneous calcaneal osteotomy). METHODS: We describe a technique and the steps endoscopic approach of FDL transfer. RESULTS: The procedure is able to be performed safely and reproducible under perfect viewing CONCLUSION: In the future with a clinical study investigating, we purpose the results of such surgery in a cohort of patients with flexible flatfoot. Level IV Therapeutic study: case serie. No funding was received for this research project.

[A painful collapse: the flat foot management]. / Un effondrement douloureux : la prise en charge du pied plat.

Flatfoot is a progressive deformity with a collapse of the foot. Its therapeutic approach has undergone a conceptual shift. Initially focused on posterior tibial tendon insufficiency, it is now defined by a sum of anatomical alterations resulting in a three-dimensional deformity. If the deformity is symptomatic, we look for hindfoot valgus, forefoot abduction and varus, as well as valgus ankle instability. The clinical rigidity of the deformities and the weight-bearing radiological examinations help guide treatment. Although plantar supports and rigid orthoses are sufficient for mild cases, surgical treatment using bone, ligament, tendon or even prosthetics procedures are the final stage of management for severe cases.

Le pied plat est une déformation progressive avec un effondrement du pied. Son approche a fait l'objet d'un changement de concept. Initialement centré sur l'insuffisance du tendon tibial postérieur, il est maintenant défini par une somme d'altérations anatomiques engendrant une déformation tridimensionnelle. Si celle-ci est symptomatique, on recherche le valgus d'arrière-pied, l'abduction et le varus d'avant-pied ainsi que l'instabilité de cheville en valgus. La rigidité clinique des déformations et les examens radiologiques en charge permettent de guider le traitement. Bien que des supports plantaires ou des orthèses plus rigides soient suffisants pour les cas légers, un traitement chirurgical par procédures osseuses, ligamentaires, tendineuses, voire prothétiques est le stade final de la prise en charge pour les cas sévères.

Supination resistance variations in foot and ankle musculoskeletal disorders: implications for diagnosis and customised interventions with wedged insoles.

BACKGROUND: Supination resistance is a clinical outcome that estimates the amount of external force required to supinate the foot. A greater supination resistance may indicate greater loads on structures responsible for generating internal supination moments across the subtalar joint during static and dynamic tasks. As such, greater supination resistance may be an expected finding in medial foot and ankle musculoskeletal disorders, such as plantar fasciopathy (PF) and posterior tibial tendon dysfunction (PTTD), whereas reduced supination resistance may be present in lateral ankle disorders, such as chronic ankle instability (CAI). However, no studies have yet investigated the changes in supination resistance across these foot and ankle musculoskeletal disorders. This study aimed to quantify supination resistance in individuals with PF, PTTD and CAI compared to healthy controls. Additionally, this study aimed to explore the changes in supination resistance following the simulation of varus and valgus wedges, which are commonly used interventions for these disorders. METHODS: Fourteen participants with PF, fourteen with PTTD, fourteen with CAI and fourteen healthy controls were recruited. Supination resistance was quantified on a level surface and on a 10-degree inclined surface with varus and valgus positions. RESULTS: Supination resistance was lower for the injured foot for CAI (p < 0.001) and greater for PTTD (p < 0.001) compared to the healthy foot. There was no significant between-foot difference observed for PF (p = 0.275) and controls (p = 0.970). In the injured foot, CAI exhibited lower supination resistance compared to controls (p < 0.001), PF (p = 0.012) and PTTD (p = 0.014). Regardless of the groups, supination resistance increased when tested on a surface with valgus inclination (p < 0.001) and decreased when tested on a surface with varus inclination (p < 0.001). CONCLUSIONS: Varus and valgus inclinations to the surface were effective in modifying supination resistance in PTTD and CAI, respectively. Supination resistance seemed unchanged in PF, and thus inclining the standing surface leads to greater between-feet asymmetries. This study also highlights the potential of wedged insoles as a mean to customise treatments and modify tissue stresses in these disorders. The findings contribute to the understanding of foot and ankle biomechanics and may aid in the development of more effective management and rehabilitation strategies.

Medial Double Arthrodesis Through Single Approach.

Triple arthrodesis is a time-tested procedure toward primary salvage in the context of posterior tibial tendon dysfunction, symptomatic rigid and severe hindfoot malalignment, end-stage degenerative and posttraumatic arthritis, and sequelae of paralytic diseases. Today, the indication for hindfoot arthrodesis is applied to correct painful deformities and arthritic joints, such as advanced cases of adult-acquired flatfoot secondary to ligament collapse and insufficiency of the posterior tibial tendon. Although the triple arthrodesis is an effective and reliable outcome procedure, the popularity of a medial double arthrodesis has increased.

Tibial Retro-Malleolar Groove Morphology in Patients With Posterior Tibialis Tendon Dysfunction.

The posterior tibial tendon is a gliding tendon which courses around the medial malleolus and fails in posterior tibialis tendon dysfunction (PTTD) leading to a flat foot deformity. Distal tibial bone spurs have been identified as a secondary sign of PTTD although they have not been quantified in detail. The aim of this study was to assess the association of tendon dysfunction with the bony morphology of the tibial retro-malleolar groove. We performed a retrospective review of the clinical presentation, plain radiographs, and 103 magnetic resonance imaging (MRI) scans in 82 consecutive patients with PTTD compared with a non-PTTD group. We carried out a quantitative and qualitative assessment of the presence of plain radiographic bone spurs, stage of PTTD and MRI imaging of the morphology of the tibial bony malleolar groove. Plain radiographic bone spurs, as a secondary sign of PTTD, were present in 21.3% of ankle radiographs. MRI bone spurs were identified in 26/41 (63.4%) for all high-grade partial and complete tears and 7/41 (17.1%) for isolated complete tears compared with only 3.9% of the non-PTTD group. There was a significant association between the presence of bone spurs on MRI imaging and high-grade partial and complete tibialis posterior tears (p < .001; odds ratio of 4.98). Eleven of 103 (10.7%) of spurs were large and in 4/103 (3.9%) were substantial enough to create a tunnel-like hypertrophic groove not previously reported. There is variation in the bony structure of the malleolar groove in PTTD not observed in the non-PTTD group. Further investigation over time may elucidate whether the groove morphology may lead to mechanical attrition of the tibialis posterior tendon and contribute to failure of healing and progressive tendon degeneration.

Single and Double Osteotomies of the Calcaneus for the Treatment of Posterior Tibial Tendon Dysfunction.

Posterior tibial tendon disfunction is one of the most commonly treated foot and ankle entities. Surgical treatment may consist of various components and is often performed on an a-la-carte basis. Commonly, joint preservative surgery for posterior tibial tendon dysfunction invariably involves one or more osteotomies of the calcaneus. This article evaluates the current existing evidence guiding providers in the selection of single or double calcaneal osteotomies.

Approach to the Ankle in Adult Acquired Flatfoot Deformity.

Adult acquired flatfoot is a progressive deformity of the foot and ankle, which frequently becomes increasingly symptomatic. The posterior tibial tendon is most commonly associated with the deformity. A targeted physical examination with plain film radiographs is the recommended initial assessment, which will further guide a physician toward procuring more advanced imaging or toward surgical intervention. In this chapter the authors review the current literature of their approach to the treatment of the ankle in end stage of adult acquired flatfoot deformity.

A comparison between the Bluman et al. and the progressive collapsing foot deformity classifications for flatfeet assessment.

INTRODUCTION: Bluman et al., flatfoot classification is based on posterior tibial tendon (PTT) dysfunction leading to a chronological appearance of several foot deformities. An expert consensus recently proposed a new classification named Progressive Collapsing Foot Deformity (PCFD) in which the focus was shifted to five different independent foot and ankle deformities and their flexibility or rigidity. The aim of this study was to compare Bluman and PCFD classifications. We hypothesize that both classifications will be reliable and that the PCFD classification will allow a larger distribution of the different types of foot deformity. MATERIALS AND METHODS: We performed a retrospective IRB-approved study including 92 flatfeet. Three foot and ankle surgeons reviewed patient files and radiographs to classify each foot using both classifications. Bluman classification was performed one time as initially described and a second time after removing the Angle of Gissane sclerosis sign. Interobserver reliabilities were determined with Fleiss' kappa values. RESULTS: Interobserver reliabilities of Bluman and PCFD classifications were, respectively, substantial 0.67 and moderate 0.55. PCFD Class C and D reliabilities were, respectively, slight 0.07 and fair 0.28. The 276 readings were spread into 10 substages in Bluman and 65 subclasses in PCFD. The progressivity of the Bluman classification prevented the combination of flexible hindfoot valgus (II Bluman, 1A PCFD), midfoot abduction (IIB, 1B) and medial column instability (IIC, 1C) which was frequent in our study (112/276 readings, 40.6%). By removing the Angle of Gissane sclerosis sign from the Bluman classification, the prevalence of stage III decreased from 44.2 to 10.1%. CONCLUSIONS: Bluman and PCFD classifications were reliable. The PCFD classification showed a larger distribution of different types of flatfeet but Classes C and D need better definition. The progressivity of Bluman classification causes inconsistencies and Gissane angle sclerosis sign is inappropriately used and might lead to incorrect surgical indications.

Transferencia del flexor hallucis longus en un paciente con síndrome pospoliomielítico con déficit de la función del tendón tibial posterior. Reporte de un caso y técnica quirúrgica / Flexor hallucis longus transfer in a patient with post-polio syndrome with posterior tibial tendon dysfunction. Case report and surgical technique

El síndrome pospoliomielítico con déficit de la función del tendón tibial posterior puede presentarse con un pie equino flexible y marcha equina (steppage) en algunos pacientes. Se describe el caso de una paciente que solo conservaba la función muscular del tendón flexor hallucis longus y se decidió su transferencia al mediopié para obtener un pie plantígrado y restaurar la dorsiflexión. Nivel de Evidencia: IV

Post-polio syndrome with posterior tibial tendon dysfunction may present a flexible clubfoot and steppage gait in some patients. We describe the case of a patient who only preserved flexor hallucis longus tendon function; therefore, we decided to transfer it to the midfoot to obtain a plantigrade foot and restore dorsiflexion. Level of Evidence: IV

Characteristics and Future Direction of Tibialis Posterior Tendinopathy Research: A Scoping Review.

Background and Objectives: Tibialis posterior tendon pathologies have been traditionally categorized into different stages of posterior tibial tendon dysfunction (PTTD), or adult acquired flatfoot deformity (AAFD), and more recently to progressive collapsing foot deformity (PCFD). The purpose of this scoping review is to synthesize and characterize literature on early stages of PTTD (previously known as Stage I and II), which we will describe as tibialis posterior tendinopathy (TPT). We aim to identify what is known about TPT, identify gaps in knowledge on the topics of TPT, and propose future research direction. Materials and Methods: We included 44 studies and categorized them into epidemiology, diagnosis, evaluation, biomechanics outcome measure, imaging, and nonsurgical treatment. Results: A majority of studies (86.4%, 38 of 44 studies) recruited patients with mean or median ages greater than 40. For studies that reported body mass index (BMI) of the patients, 81.5% had mean or median BMI meeting criteria for being overweight. All but two papers described study populations as predominantly or entirely female gender. Biomechanical studies characterized findings associated with TPT to include increased forefoot abduction and rearfoot eversion during gait cycle, weak hip and ankle performance, and poor balance. Research on non-surgical treatment focused on orthotics with evidence mostly limited to observational studies. The optimal exercise regimen for the management of TPT remains unclear due to the limited number of high-quality studies. Conclusions: More epidemiological studies from diverse patient populations are necessary to better understand prevalence, incidence, and risk factors for TPT. The lack of high-quality studies investigating nonsurgical treatment options is concerning because, regardless of coexisting foot deformity, the initial treatment for TPT is typically conservative. Additional studies comparing various exercise programs may help identify optimal exercise therapy, and investigation into further nonsurgical treatments is needed to optimize the management for TPT.

How Common is Subsequent Posterior Tibial Tendon Dysfunction or Tarsal Tunnel Syndrome After Ankle Sprain Injury?

Posterior tibial tendon dysfunction (PTTD) and tarsal tunnel syndrome (TTS) are debilitating conditions reported to occur after ankle sprain due to their proximity to the ankle complex. The objective of this study was to investigate the incidence of PTTD and TTS in the 2 years following an ankle sprain and which variables are associated with its onset. In total, 22,966 individuals in the Military Health System diagnosed with ankle sprain between 2010 and 2011 were followed for 2 years. The incidence of PTTD and TTS after ankle sprain was identified. Binary logistic regression was used to identify potential demographic or medical history factors associated with PTTD or TTS. In total, 617 (2.7%) received a PTTD diagnosis and 127 (0.6%) received a TTS diagnosis. Active-duty status (odds ratio [OR] 2.18, 95% confidence interval [CI] 1.70-2.79), increasing age (OR 1.03, 95% CI 1.02-1.04), female sex (OR 1.58, 95% CI 1.28-1.95), and if the sprain location was specified by the diagnosis (versus unspecified location) and did not include a fracture contributed to significantly higher (p < 0.001) risk of developing PTTD. Greater age (OR 1.06, 95% CI 1.03-1.09), female sex (OR 2.73, 95% CI 1.74-4.29), history of metabolic syndrome (OR 1.73, 95% CI 1.03-2.89), and active-duty status (OR 2.28, 95% CI 1.38-3.77) also significantly increased the odds of developing TTS, while sustaining a concurrent ankle fracture with the initial ankle sprain (OR 0.45, 95% CI 0.28-0.70) significantly decreased the odds. PTTD and TTS were not common after ankle sprain. However, they still merit consideration as postinjury sequelae, especially in patients with persistent symptoms. Increasing age, type of sprain, female sex, metabolic syndrome, and active-duty status were all significantly associated with the development of one or both subsequent injuries. This work provides normative data for incidence rates of these subsequent injuries and can help increase awareness of these conditions, leading to improved management of refractory ankle sprain injuries.

Histologic grading correlates with inflammatory biomarkers in tibialis posterior tendon dysfunction.

BACKGROUND: It has been theorized that tibialis posterior tendon dysfunction (TPTD) is a degenerative process unrelated to inflammation. The purpose of this study was to determine if inflammatory cytokines, matrix metalloproteases (MMPs), and glutamate were elevated in diseased tibialis posterior tendons (TPTs). METHODS: Matched diseased TPT, TPT insertion, and flexor digitorum longus (FDL) samples were collected from 21 patients. The samples were individually incubated in media, which was analyzed for inflammatory cytokines, MMPs, and glutamate. Histology and statistical analyses were performed. RESULTS: Diseased TPT and TPT insertion were significantly elevated compared to transferred FDL in eight inflammatory markers (p < 0.005). Only the diseased TPT was significantly elevated compared to the transferred FDL tendons for glutamate (p < 0.01). Histologic grading correlated with inflammatory cytokine levels. CONCLUSION: Diseased TPT and TPT insertion demonstrated significantly elevated levels of inflammatory markers compared to the transferred tendons used as controls, suggesting a role for inflammation in the disease process. The amount of inflammation correlated with increased tendon degradation. LEVEL OF EVIDENCE: Level III.

Operative Management: Spring Ligament.

Pes planovalgus is a multiplanar deformity consisting of a combination of hindfoot valgus, collapse of the medial longitudinal arch, forefoot varus, and forefoot abduction. This deformity is often associated with posterior tibial tendon dysfunction. Collapse of the medial longitudinal arch increases stress to the static stabilizers of the medial column including the deltoid ligament, spring ligament, plantar fascia, plantar and talocalcaneal interosseous ligaments, as well as the talonavicular and naviculocuneiform capsules. There is a higher incidence of concomitant spring ligament pathology in pes planovalgus deformity and posterior tibial tendon dysfunction based on magnetic resonance imaging and intraoperative observation than in other static stabilizers.

Double Versus Triple Arthrodesis Fusion Rates: A Systematic Review.

Hindfoot arthrodesis is often required for end-staged deformities, such as posterior tibial tendon dysfunction, osteoarthritis, or rheumatoid arthritis. Although the need for hindfoot arthrodesis is generally accepted in severe deformities, there is a debate whether a double or triple arthrodesis should be performed. The aim of our systematic review is to review the fusion rates and mean time to fusion in double and triple arthrodesis. A total of 184 articles were identified using the keyword search through the database of articles published from 2005 to 2017. After review by 3 physicians, a total of 13 articles met the eligibility criteria. The reason for double or triple arthrodesis within the studies were posterior tibial tendon dysfunction, tarsal coalition, degenerative joint disease, osteoarthritis, rheumatoid arthritis, Charcot Marie Tooth, Multiple Sclerosis, Polio, neuromuscular disorder, cerebral palsy, acrodystrophic neuropathy, clubfoot, post-traumatic, and seronegative arthropathy (spondyloarthritis). Within these 13 studies, there were a total of 343 (6-95) subjects extremities operated on. The overall fusion rate for double arthrodesis was 91.75% (289/315) compared to 92.86% (26/28) triple arthrodesis fusion rate, p value .8370. The mean time to fusion for double arthrodesis was 17.96 ± 7.96 weeks compared to 16.70 ± 8.18 weeks for triple arthrodesis, p value = .8133. There are risks associated with triple arthrodesis including increased surgical times, lateral wound complications, residual deformity, surgical costs and peri-articular arthritis. Given the benefits of double arthrodesis over triple arthrodesis and the nearly equivalent fusion rates and time to fusion, double arthrodesis is an effective alternative to triple arthrodesis. The authors of this systematic review recommend double arthrodesis as the hindfoot fusion procedure of choice.

Does tibialis posterior dysfunction correlate with a worse radiographic overall alignment in progressive collapsing foot deformity? A retrospective study.

BACKGROUND: Posterior Tibial Tendon (PTT) dysfunction is considered to have an important role in Progressive Collapsing Foot Deformity (PCFD). The objective of our study was to assess the relationship between PTT status and three-dimensional foot deformity in PCFD. METHODS: Records from 25 patients with PCFD were included for analysis. The PTT was considered deficient in patients with a positive single heel rise test or a deficit in inversion strength. Three-dimensional foot deformity was assessed using the Foot and Ankle Offset (FAO) from Weight-Bearing-CT imaging. Hindfoot valgus, midfoot abduction and medial longitudinal arch collapse were assessed on X-Rays using hindfoot moment arm, talonavicular coverage angle and Meary's angle respectively. Deland and Rosenberg MRI classifications were used to classify PTT degeneration. RESULTS: PCFD with PTT deficit (13/25) had a mean FAO of 7.75 + /- 3.8% whereas PCFD without PTT deficit had a mean FAO of 6.68 + /- 3.9% (p = 0.49). No significant difference was found between these groups on the hindfoot moment arm and the talonavicular coverage angle (respectively p = 0.54 and 0.32), whereas the Meary's angle was significantly higher in case of PCFD with PTT deficit (p = 0.037). No significant association was found between PTT degeneration on MRI and FAO. CONCLUSION: PCFD associated three-dimensional deformity, hindfoot valgus and midfoot abduction were not associated with PTT dysfunction. PTT dysfunction was only associated with a worse medial longitudinal arch collapse in our study. Considering our results, it does not appear that PTT is the main contributor to PCFD. LEVEL OF EVIDENCE: Level III, Retrospective Comparative Study.

Postural Control Differences between Patients with Posterior Tibial Tendon Dysfunction and Healthy People during Gait.

BACKGROUND: Patients with posterior tibial tendon dysfunction (PTTD) may exhibit postural instability during walking likely due to a loss of medial longitudinal arch, abnormal foot alignment, and pain. While many studies have investigated gait alterations in PTTD, there is no understanding of dynamic postural control mechanisms in this population during gait, which will help guide rehabilitation and gait training programs for patients with PTTD. The purpose of the study was to assess dynamic postural control mechanisms in patients with stage II PTTD as compared to age and gender matched healthy controls. METHODS: Eleven patients with stage II PTTD (4 males and 7 females; age 59 ± 1 years; height 1.66 ± 0.12 m; mass 84.2 ± 16.0 kg) and ten gender and age matched controls were recruited in this study. Participants were asked to walk along a 10 m walkway. Ten Vicon cameras and four AMTI force platforms were used to collect kinematic and center of pressure (COP) data while participants performed gait. To test differences between PTTD vs. control groups, independent t-tests (set at α < 0.05) were performed. RESULTS: Patients with PTTD had significantly higher double stance ratio (+23%) and anterior-posterior (AP) time to contact (TTC) percentage (+16%) as compared to healthy control. However, PTTD had lower AP COP excursion (-19%), AP COP velocity (-30%), and medial-lateral (ML) COP velocity (-40%) as compared to healthy controls. Mean ML COP trace values for PTTD were significantly decreased (-23%) as compared to controls, indicating COP trace for PTTD tends to be closer to the medial boundary than controls during single-support phase of walking. CONCLUSION: PTTD patients showed more conservative and cautious postural strategies which may help maintain balance and reduce the need for postural adjustment during PTTD gait. They also showed more medially shifted COP patterns than healthy controls during single-support phase of walking. Dynamic postural control outcomes could be used to develop effective gait training programs aimed at alleviating a medial shift of COP (everted foot) for individuals with PTTD in order to improve their functionality and gait efficiency.

Intra- and Interobserver Reliability of the New Classification System of Progressive Collapsing Foot Deformity.

BACKGROUND: Historical concept of flatfoot as posterior tibial tendon dysfunction (PTTD) has been questioned. Recently, the consensus group published a new classification system and recommended renaming PTTD to Progressive Collapsing Foot Deformity (PCFD). The new PCFD classification could be effective in providing comprehensive information on the deformity. To date, there has been no study reporting intra- and interobserver reliability and the frequency of each class in PCFD classification. METHODS: This was a single-center, retrospective study conducted from prospectively collected registry data. A consecutive cohort of PCFD patients evaluated from February 2015 to October 2020 was included, consisting of 92 feet in 84 patients. Classification of each patient was made using characteristic clinical and radiographic findings by 3 independent observers. Frequencies of each class and subclass were assessed. Intraobserver and inteobserver reliabilities were analyzed with Cohen kappa and Fleiss kappa, respectively. RESULTS: Mean sample age was 54.4, 38% was male and 62% were female. 1ABC (25.4%) was the most common subclass, followed by 1AC (8.7%) and 1ABCD (6.9%). Only a small percentage of patients had isolated deformity. Class A was the most frequent component (89.5%), followed by C in 86.2% of the cases. Moderate interobserver reliability (Fleiss kappa = 0.561, P < .001, 95% CI 0.528-0.594) was found for overall classification. Very good intraobserver reliability was found (Cohen kappa = 0.851, P < .001, 95% CI 0.777-0.926). CONCLUSION: Almost half (49.3%) of patients had a presentation dominantly involving the hindfoot (A) with various combinations of midfoot and/or forefoot deformity (B), (C) with or without subtalar joint involvement (D). The new system may cover all possible combinations of the PCFD, providing a comprehensive description and guiding treatment in a systematic and individualized manner, but this initial study suggests an opportunity to improve overall interobserver reliability. LEVEL OF EVIDENCE: Level III, retrospective diagnostic study.