The acquired flatfoot, often called progressive collapsing foot deformity, frequently includes attenuation or failure of the spring ligament. Reconstruction of the spring ligament has been proposed in conjunction with other bone and soft tissue reconstruction techniques. In this study, we compared a tendon-graft reconstruction with suture tape augmentation in a cadaveric flatfoot model. Eight matched-pair fresh-frozen cadaver feet underwent flatfoot creation and reconstruction. The feet were cyclically loaded with 16,000 cycles from 200 N to 1.5× body weight at 1 Hz. Each foot was randomly assigned to undergo either suture tape or tendon graft reconstruction. Radiographic parameters and foot motion were measured at baseline, following creation of the collapsed arch deformity, and after repair. The cadaveric flatfoot model was successfully created, demonstrated by significant (P < .05) changes in Meary angle (mean change = +9.4 ± 6.4 degrees), talonavicular coverage angle (mean change = +15.6 ± 9.2 degrees), medial cuneiform height (mean change = -6.6 ± 4.1 mm), and calcaneal pitch (mean change = -2.6 ± 2.2 degrees). The tendon graft repair had significant improvements compared with flatfoot in the Meary angle (mean change = -6.4 ± 3.6 degrees), talonavicular coverage angle (mean change = -6.4 ± 5.2 degrees), calcaneal pitch (mean change = +1.9 ± 1.7 degrees), and medial cuneiform height (mean change = +3.7 ± 2.4 mm). The suture tape repair had significant improvements compared with flatfoot of talonavicular coverage angle (mean change = -8.1 ± 4.1) and calcaneal pitch (mean change = +2.9 ± 0.6). Inversion and eversion data showed hindfoot motion preserved from native to repair conditions. In load-to-failure testing, the tendon graft group had 1 failure at the interference screw and 1 midsubstance failure of the tendon graft. The suture tape group had 3 failures at the interference screws and 1 failure of the suture tape. Both techniques restored arch alignment from the flatfoot condition and preserved hindfoot motion in a cadaveric flatfoot model. Both techniques may provide a viable approach to restore alignment during flatfoot reconstruction. Both were mechanically stable under cyclic loading in this cadaver model; the tendon graft technique has a theoretical benefit of biological incorporation.

To explore the effectiveness of the flexor digitorum longus (FDL) transfer combined with single-bundle spring ligament reconstruction and medial displacement calcaneal osteotomy in the treatment of stage ⅠAB progressive collapsing foot deformity (PCFD). Between January 2019 and September 2023, 19 patients (19 feet) with stage ⅠAB PCFD were treated with FDL transfer combined with single-bundle spring ligament reconstruction and medial displacement calcaneal osteotomy. There were 11 males and 8 females, aged 18 to 60 years, with an average age of 45.5 years. Nine cases were on the left foot and 10 cases on the right foot. The disease duration was 9-21 months, with an average of 12.3 months. Postoperatively, the effectiveness was evaluated by visual analogue scale (VAS) for pain, American Orthopaedic Foot and Ankle Society (AOFAS) score, and Tegner score. Based on X-ray films, the talonavicular coverage angle (TNCA), talus-first metatarsal angle (T1MT), Meary angle, and pitch angle were measured. The plantar pressure parameters of the foot were measured by the Footscan plantar pressure measurement system, including peak pressure and load of the forefoot, midfoot, and hind foot. The patients' satisfaction with the surgical outcome was evaluated. All 19 surgeries were successfully completed. One patient had poor incision healing after operation, while the incisions of the remaining patients healed by first intention. All patients were followed up 12-28 months (mean, 16.8 months). At last follow-up, the VAS score significantly decreased compared with that before operation, and the AOFAS score and Tegner score significantly increased ( P<0.05). Radiological measurements showed that the TNCA, T1MT, Meary angle, and Pitch angle all significantly improved compared with those before operation ( P<0.05). Plantar pressure tests indicated that the peak pressures of the forefoot and midfoot significantly reduced compared with those before operation ( P<0.05), while the peak pressure of the hind foot showed no significant change ( P>0.05). The forefoot load significantly increased and the midfoot load decreased compared with those before operation ( P<0.05), while the hind foot load showed no significant change ( P>0.05). The total satisfaction rate of patients with the surgical outcome (very satisfied+satisfied) reached 84.2% (16/19). The FDL transfer combined with single-bundle spring ligament reconstruction and medial displacement calcaneal osteotomy can effectively correct the stage ⅠAB PCFD, improve the abnormal distribution of plantar pressure and load, alleviate foot pain symptoms, and improve foot movement function. The patient's satisfaction is high. However, the long-term effectiveness still needs to be further observed and clarified.

Translated article] Cadaveric biomechanical study of the calcaneonavicular ligament in midfoot medial column collapse comparing two surgical techniques

Research Type: Level 4 – Case series Introduction/Purpose: Adult-acquired flatfoot deformity (AAFD) can occur due to posterior tibialis tendon (PTT) degeneration and spring and deltoid ligament insufficiency. Some repair techniques reconstruct the spring ligament. A current repair technique involves suture-tape augmentation with anchors from the calcaneus to the navicular. We have developed a novel tendon graft reconstruction repair utilizing graft tissue from the medial talar neck to the navicular. The purpose of this study was to compare these two reconstruction methods in a cadaveric flatfoot model. Methods: Five matched-pair fresh-frozen cadaver feet (four female and one male, age 76.4±11.3 years) underwent flatfoot creation and reconstruction. The feet were cyclically loaded with 16,000 cycles from 200 N to 1.5× body weight at 1 Hz. Each foot was randomly assigned to undergo either suture-tape augmentation or tendon graft reconstruction. Radiographic parameters, foot motion, and pressure mapping were measured before loading, after loading, and after repair. Ramp-to-failure testing was conducted as well. Results: The cadaveric flatfoot model was successfully created, demonstrated by significant changes in Meary’s angle (mean change = 7.4°, &lt; .05), talonavicular coverage (mean change = 14.7°, p &lt; .05), and medial cuneiform height (mean change = 5.6mm, p &lt; .05). The tendon graft technique (mean change = 7.1°, p &lt; .05) resulted in more significant improvements in Meary’s angle compared to the other technique (mean change = 2.3°). There were no significant differences in inversion and eversion data between repair techniques. The tendon graft technique had a significantly higher failure threshold (mean failure = 2864.9 N, p&lt; 0.05) compared to the other technique (mean failure = 2594.8N), and a lower failure rate (1/5 failed with tendon graft vs. 3/5 failed with suture tape). Conclusion: Both techniques successfully restored arch alignment and preserved hindfoot motion in a cadaveric flatfoot model. However, the tendon graft technique demonstrated greater improvement in alignment and failure resistance. Further evaluation of the tendon graft technique is necessary to determine its viability as a substitute for stabilizing procedures like osteotomies or fusions. Given the potential for host tissue incorporation, the tendon graft technique may offer better long-term durability. Foot Specimen Set Up for Loading Figure 1: (A) Lateral view of the foot with retro-reflective markers and of the Achilles tendon sandwiched between sailcloth. (B) Anterior view of the foot with retro-reflective markers.

Research Type: Level 3 - Retrospective cohort study, Case-control study, Meta-analysis of Level 3 studies Introduction/Purpose: Progressive collapsing foot deformity (PCFD) is a complex condition characterized by progressive ligamentous and osseous changes in the hindfoot, midfoot, and forefoot. While osseous changes at the subtalar and transverse tarsal joints have been well-studied, ligamentous anatomy in PFCD is less understood. This study aims to evaluate the cervical ligament, interosseous (IO) talocalcaneal ligament, and the spring ligament in patients with PCFD versus controls using magnetic resonance imaging (MRI) analysis. Methods: A retrospective review was conducted at a single academic institution, analyzing MRI (1.5+ Tesla) and weight-bearing radiographs of 39 patients (23 with PCFD and 16 normal controls). MRIs were used to measure the coronal plane orientation of the interosseous talocalcaneal, cervical, and spring ligaments relative to the subtalar joint medial facet. Radiographic data was collected from weight-bearing x-rays, including anteroposterior (AP) talonavicular coverage percentage, AP talocalcaneal angle (Kite angle), lateral talar-first metatarsal angle (Meary Angle), talar declination angle, and calcaneal pitch. Two observers measured each radiographic and MRI angle. Statistical analysis included an independent student t-test and intraclass correlation coefficient (ICC) to assess agreement and inter- and intra-observer reliability between each observer. Results: PCFD patients demonstrated significantly more horizontal ligament orientations than controls, with reduced cervical (25.5° vs. 45°, p &lt; 0.001), spring (11.5° vs. 23.1°, p &lt; 0.001), and interosseous talocalcaneal ligament angles (39.5° vs. 49.0°, p = 0.005). Radiographically, PCFD patients had decreased talonavicular coverage (64.5% vs. 80.9%, p &lt; 0.001), increased Meary angle (22.2° vs. -2.3°, p &lt; 0.001), increased talar declination (37.0° vs. 26.0°, p &lt; 0.001), increased Kite Angle (20.7° vs 17.2°, p &lt; 0.079) and decreased calcaneal pitch (15.5° vs. 24.6°, p &lt; 0.001). Inter- and intra-observer reliability was excellent, with ICC values exceeding 0.94 for all measurements except the interosseous talocalcaneal ligament angle (ICC = 0.83). Conclusion: Patients with progressive collapsing foot deformity (PCFD) experience significantly more horizontal orientation of the cervical, spring, and interosseous talocalcaneal ligaments compared to controls in the non-weightbearing state. These findings may aid future research into the potential reconstruction of these ligaments to prevent progression or restore anatomy in patients with PCFD.

Research Type: Level 4 – Case series Introduction/Purpose: Operative treatment for Progressive Collapsing Foot Deformity (PCFD) is indicated for symptomatic patients who have failed conservative measures, aiming to correct hindfoot valgus (Class A), forefoot/midfoot abduction (Class B), forefoot varus/medial column instability (Class C), and peritalar subluxation (Class D). In flexible PCFD (stage 1), joint-sparing reconstructive procedures preserve mobility of the triple joint complex. These typically include osteotomies, tendon transfers or reattachments, and ligament retensioning/reconstructions. This study analyzed a cohort of PCFD patients who underwent joint-sparing reconstruction by a single surgeon following a standardized protocol, with 3D-measurements derived from Weight Bearing CT (WBCT). We hypothesized that these procedures would achieve significant radiological correction across different PCFD classes. Methods: This IRB-approved retrospective cohort study included 43 adult PCFD patients (24 female, 19 male) with a mean age of 47.8 years (SD 17.8) and mean BMI of 31.0 kg/m² (SD 7.0). All patients underwent joint-sparing reconstructive procedures performed by a single surgeon at a single institution, with a minimum follow-up of three months (mean follow-up 9.3 months). Postoperative management included six weeks of non-weightbearing in a splint/cast and boot, followed by progressive weight-bearing in a boot between week six and twelve. Preoperative and three-month postoperative WBCT scans assessed alignment using a combination of PCFD semiautomated and manual measurements, involving parameters representative for PCFD classes A (Foot and Ankle Offset, Hindfoot Moment Arm), B (Talonavicular Coverage Angle), C (Forefoot Arch Angle, Sagittal Talus First Metatarsal Angle), and D (Middle Facet Subluxation). All surgical procedures performed and any associated complications were recorded. Statistical significance was set at P &lt; .05. Results: Plantarizing first ray procedures (Cotton or Lapicotton) were most frequently performed (100%, mean wedge size 8.2mm), followed by Medial Displacement Calcaneal Osteotomy (MDCO) (93%, mean displacement 9.3mm), Peroneus brevis to longus transfer (86%), posterior tibial tendon (PTT) procedure (84%) and Spring ligament reconstruction (67%). All radiographic parameters showed significant improvement at three months postoperatively (P &lt; 0.01). Three patients (7%) experienced complications. One patient had both a minor complication (superficial wound dehiscence) and a major complication (nonunion MDCO). The other two patients developed sensitive neuritis and nonunion of Lapicotton and MDCO, respectively. Conclusion: This study highlights the potential of reconstructive PCFD surgery, demonstrating promising radiographic short-term radiological outcomes. First ray procedures, MDCO, peroneal and posterior tibial tendon procedures were most frequently performed. While our complication rate aligns with previous literature, we observed two non-unions among 40 MDCO, a higher rate than previously reported. Longer follow-up with WBCT scans is needed to assess the durability of correction. Additionally, studies evaluating clinical outcomes after joint-sparing procedures are warranted.

Background:Progressive collapsing foot deformity (PCFD) is a complex condition characterized by progressive ligamentous and osseous changes in the hindfoot, midfoot, and forefoot. Although osseous changes at the subtalar and transverse tarsal joints have been well studied, ligamentous anatomy in PCFD is less understood. This study evaluates the cervical, interosseous talocalcaneal, and superomedial fibers of the spring ligament in patients with PCFD vs controls using magnetic resonance imaging (MRI) analysis.Methods:Nonweightbearing MRI and weightbearing radiographs of 39 patients (23 PCFD, 16 controls) were retrospectively reviewed. MRIs measured the coronal plane orientation of the interosseous talocalcaneal, cervical, and superomedial spring ligaments relative to the subtalar joint middle facet. Radiographic data included anteroposterior (AP) talonavicular coverage percentage, AP talocalcaneal angle (Kite), lateral talar–first metatarsal angle (Meary), talar declination angle, and calcaneal pitch. Two observers measured each radiographic and MRI angle. Statistical analysis included an independent t test and intraclass correlation coefficient (ICC) to assess interobserver reliability.Results:PCFD patients demonstrated significantly more horizontal ligament orientations than controls, with reduced cervical (25.5 vs 45 degrees, P < .001), superomedial spring (11.5 vs 23.1 degrees, P < .001), and interosseous talocalcaneal ligament angles (39.5 vs 49.0 degrees, P = .005). Radiographically, PCFD patients had decreased talonavicular coverage (64.5% vs 80.9%, P < .001), increased Meary angle (22.2 vs −2.3 degrees, P < .001), increased talar declination (37.0 vs 20.6 degrees, P < .001), increased Kite angle (20.7 vs 17.2 degrees, P = .079), and decreased calcaneal pitch (15.5 vs 24.6 degrees, P < .001). Interobserver reliability was excellent, with ICC values exceeding 0.94 for all measurements except interosseous talocalcaneal ligament angle (ICC = 0.83).Conclusion:On nonweightbearing MRI, PCFD patients showed more horizontal orientation of key subtalar ligaments than controls; whether these differences persist under physiologic load should be confirmed with weightbearing imaging.

Background: Spring ligament (SL) injuries are primarily associated with progressive collapsing flatfoot deformity, but can also occur due to trauma. It remains unclear whether the morphological changes following trauma differ from those caused by chronic overload. The aim of this study was (1) to analyze whether a relationship exists between the injury pattern and foot deformity and (2) to evaluate whether there is a distinction between trauma-related and non-trauma-related injuries. Method: We prospectively enrolled 198 patients with a median age of 57 years (range, 13 to 86 years; female, 127 (64%); male, 71 (36%)) who had a clinically diagnosed, surgically confirmed, and classified SL injury. We used weight-bearing standard X-rays to assess foot deformity. The control group consisted of 30 patients (median age 51 years, range, 44–66; female, 21 (70.0%); male, 9 (30.0%)) with no foot deformities or prior foot surgeries. Results: A 41.9% incidence of trauma was identified as the cause of these injuries, accounting for 16 (20.8%) of isolated injuries to the SL, 30 (42.9%) of SL injury accompanied by a posterior tibial (PT) tendon avulsion, and 37 (72.5%) of SL injury alongside a bony avulsion at the navicular injuries. The odds of being post-traumatic decreased with each year of age by a factor of 0.97 (95% CI: 0.95–0.99). Conclusions: While all radiographic measurements for flatfoot deformity became pathological after an injury to the SL, they did not accurately predict the injury patterns of the SL and distal PT tendon. Generally, post-traumatic cases exhibited lower severity of foot deformity, suggesting that other structures beyond the SL may contribute to the development of flatfoot deformity.

Repair or reconstruction of spring ligament complex (SLC) is strongly recommended in the surgical treatment of flexible pes planovalgus, as this structure plays a major role in supplying the integrity of the medial longitudinal arch. The SLC is located underneath the terminal portion of the posterior tibial tendon (PTT) and the navicular tubercle, which makes visualization and repair grueling and often inadequate, unless the overlying structures are mobilized and removed temporarily out of its path. Previously defined techniques for mobilizing the terminal portion of the PTT include cutting the tendon body or detaching its distal end from the navicular bone. However, tendon-to-tendon and tendon-to-bone repairs inevitably heal with scar tissue, demonstrate inferior tissue strength and carry the risk of rupture, elongation and loss of function. Any technique that preserves the tendon and its bony attachment during mobilization of the PTT would definitely be more advantageous in terms of postoperative strength and function. This article defines a navicular tubercle osteotomy technique to mobilize the terminal portion of PTT without violating the tendon body or its bony insertion site. This technique provides perfect visualization and access to the SLC, talo-calcaneal joint and deep plantar structures of the foot. It also enables superior initial fixation of the detached fragment compared with tendon-to-tendon or tendon-to-bone fixation, allows scar-free healing at the osteotomy site and permits distalization of the insertion site of the PTT for retensioning. Level of Evidence: IV.

Increased Achilles tendon force required to achieve heel-lift in cadaveric model of midfoot instability - A cadaveric study.

Novel technique for deltoid spring complex reconstruction in progressive collapsing foot disorder.

Assessing the relationship between planter fascia and planter calcaneonavicular ligament thickness in individuals suffering from planter fasciitis using musculoskeletal ultrasonography

To investigate the effectiveness of spring ligament repair combined with subtalar arthroereisis (STA) and the Kidner procedure for treating children's flexible flatfoot with painful accessory navicular. A retrospective analysis was conducted on clinical data from 45 children (45 feet) aged 7-14 years with flexible flatfoot and painful accessory navicular who met the selection criteria and were treated between February 2018 and May 2022. Among them, 23 cases (23 feet) were treated with spring ligament repair combined with STA and Kidner procedure (observation group), while 22 cases (22 feet) received STA with Kidner procedure alone (control group). Comparison of baseline data between the two groups including gender, age, affected side, preoperative visual analogue scale (VAS) score, American Orthopaedic Foot & Ankle Society (AOFAS) score, talonavicular coverage angle (TCA), talus-first metatarsal angle (T1MT), talus-second metatarsal angle (T2MT), talus first plantar angle (Meary angle), calcaneal inclination angle (Pitch angle) showed no significant differences ( P>0.05). The following parameters were recorded and compared between the two groups: operation time, intraoperative blood loss, incision length, hospital stay, time to full weight-bearing, and complication rates. Foot pain and functional recovery were assessed using the VAS score and AOFAS score preoperatively and at last follow-up. Radiographic measurements including TCA, T1MT, T2MT, Meary angle, and Pitch angle were analyzed by comparing preoperative to last follow-up values. Both groups of patients successfully completed the surgery without any procedure-related complications such as vascular, neural, or tendon injury. The operation time in the observation group was significantly longer than that in the control group ( P<0.05). There was no significant difference between the two groups in terms of intraoperative blood loss, incision length, hospital stay, or time to full weight-bearing ( P>0.05). All patients were followed up 23-47 months (mean, 33.7 months). In the control group, 1 patient experienced discomfort during walking, attributed to screw irritation in the sinus tarsi, which resolved after 2-3 months of rehabilitation. None of the remaining patients developed complications such as sinus tarsi screw loosening, peroneal tendon contracture, or wound infection. At last follow-up, the observation group showed significantly better improvements in radiographic parameters (TCA, T1MT, T2MT, Meary angle, Pitch angle) and greater reductions in VAS and AOFAS scores compared to the control group ( P<0.05). The combined procedure of spring ligament repair, STA, and Kidner procedure for children's flexible flatfoot with painful accessory navicular demonstrates significant improvements in foot appearance, arch collapse correction, and pain relief. This technique offers technical simplicity, minimal intraoperative complications, and satisfactory clinical outcomes.

Progressive collapsing flatfoot deformities (PCFD) are commonly the result of the impairment of medial hindfoot soft tissue structures including the posterior tibial tendon, deltoid, and spring ligament. These deformities have been treated surgically via calcaneal osteotomies and tendon transfers; only recently has soft tissue reconstruction gained momentum. Advancements have now made available graft materials to help augment and stabilize ligament repairs to further improve results. Medial hindfoot ligament reconstruction procedures require surgeon familiarity with soft tissue and osseocartilaginous structures. We assessed 20 cadaveric specimens after a simulated medial hindfoot ligament reconstruction procedure focusing on the sustentaculum bone tunnel. Post-procedure anatomic and radiographic observations carefully detailed any damage to anatomic structures. The sustentaculum tunnel guidewire at the lateral calcaneal cortex was documented, including angular position in relation to the subtalar joint. We determined that the posterior-inferior aspect of the lateral calcaneal surface serves as the ideal target region for the placement of the guidewire and subsequent tunnel drilling. Complications increased when drilling tunnels at 7 mm in diameter. The results provide insight for medial-to-lateral drilling of the calcaneus when performing tunneling techniques and can be used to help optimize surgical results when for deltoid/spring ligament repair augmented with graft materials.Level of Evidence: Level V.

The aim of this study is to reviewthe variation in description of the individual bands comprising the deltoid and spring ligaments in anatomical dissection studies and to propose a novel approach to describe the structure. A literature search for cadaveric studies identifying anatomical variations in the deltoid and spring ligament complexes was conducted using PubMed and Medline databases. The inclusion criteria encompassed human cadaveric dissection studies with measurement of individual deltoid and spring ligament bandsin the English languageand with full-text availability. The following studies were excluded: animal studies, articles describing surgical repair approaches, and radiological assessment studies without cadaveric dissection. The demographic data, parameters of individual components, as well as the morphological structure of individual deltoid bands were summarised. Out of the 18,208 studies from the database search, 11 articles were included in this study. Thirteen additional studies were obtained from the bibliographies, resulting in a total of 24 studies with 528 ankles evaluated. Due to the complexity of their anatomical relationships, the deltoid and spring ligaments should be described as a single entity: the "deltoid-spring ligament complex". Its gross morphology can be described as triangular, trapezoidal, and rectangular. It can be differentiated into the deep deltoid and the superficial deltospring ligament, which are connected. The latter encompasses the superficial deltoid and superomedial part of the spring ligament. The deep plantar ligament and "the inferior spring ligament" are separate entities reflecting their discrete natures and histological differences. The superficial deltospring ligament can be divided into contiguous segments with variable bands (thickening but not true ligaments). Each segment can be clinically assessed en masse. This description can help to clarify the nomenclature.

IntroductionThe use of an arthroereisis screw is well described in the paediatric population for the correction of flexible flat feet. There are no long-term studies of its use in adults. We performed a functional and radiographic evaluation of a single centre, single surgeon series following the use of a subtalar arthroereisis screw, to augment reconstruction in adult patients with acquired adult flat foot deformity secondary to spring ligament / tibialis posterior tendon failure.MethodsWe performed a retrospective review of 40 consecutive feet with stage 2 PTTI that underwent flexor digitorum longus transfer, reefing of the spring ligament, translational medialising calcanaeal osteotomy and augmentation with an arthroereisis screw (Kalix, Integra; 22 feet or ProStop, Arthrex; 3 feet), between 2005 and 2021. All arthroereisis screws were electively removed at 6 months. Radiographic values were assessed pre- and post-operatively at 1-year with functional results both at 1-year and average 10-year follow-up.ResultsThe mean age of patients at surgery was 60 years (range 44–77 years). There was a significant improvement p&lt;0.05) in radiographic parameters (calcaneal pitch, Mearys angle, medial column height, talus to 1st and 2nd metatarsal angle and talonavicular coverage). There were no re-operations. Manchester Oxford Foot Questionnaire, EQ-5D and VAS scores at an average of 10.6 years for pain were reported as 2.3 (range 0–64, Likert scale), 0.94 (range -0.59–1) and 0.2 (0–10), respectively. Health TODAY averaged at 91.4%.ConclusionWe conclude that the use of an arthroereisis screw is a promising adjunct to conventional reconstruction in adult PTTI that protects the spring ligament repair and tendon transfer during the initial healing time of the soft tissues. Excellent radiological and functional results were obtained in our cohort with high levels of patient satisfaction at long-term follow-up.

Achilles Tendon Rupture (ATR) is a common yet debilitating injury that affects individuals of all ages and activity levels. Several theories describe the pathogenesis of ATR. This study aims to evaluate if there is increased medial column instability in terms of talonavicular laxity or first ray instability in patients with ATR. Patients were recruited from a database of Tendoachilles (TA) ruptures presenting to the clinic. All patients underwent non operative treatment. Patients with pre-existing foot surgery, arthropathy or generalised laxity were excluded. A total of 15 TA ruptures were assessed for first ray instability and Spring Ligament (SL) incompetence. Results: No patients had pre-existing Achilles problems or foot instability in our cohort. One patient had a chronic unilateral rupture, missed an initial presentation and had treatment. TA maximum Anteroposterior (AP) thickness between affected and unaffected feet demonstrated no significant difference. ATR feet demonstrated greater midfoot instability in terms of both Talonavicular (TN) laxity and First Ray Instability (FRI) in all ATR feet (p&lt;0.05). Despite medial column instability the incidence of significant valgus impingement pain was 8/15 cases. Both were statistically increased. This suggests that combined pathogenesis may be responsible for both pathologies. In conclusion, this is the first study to our knowledge that reports increased medial column laxity being present in all ATR feet. External biomechanical factors in a predisposed foot help generate an internal moment/ force that overloads the TA. The relationship between intrinsic foot biomechanics and ATR has not been described. Future treatments may therefore be directed at restoring midfoot stability using orthotics or surgery to help restore biomechanics and to help offload the TA and protect the foot from future re-ruptures.

Introduction: Management strategies for stage II tibialis posterior tendon dysfunction are centered on tendon transfers and osteotomies. One of the most commonly used tendon transfers is flexor digitorum longus (FDL) tendon to navicular, but its superiority over transfers to other locations or transfers of other tendons, along with the role of spring ligament and tibialis posterior tendons, have not been objectively evaluated. Aims: We aimed to quantify both the location and magnitude of secondary stresses that develop as a consequence of the initial pathology. Methods: In this study, we used a computational model to study flat foot development and evaluate the effects of various tendon transfers and failures of passive structural elements, as well as their effect on the biomechanics of the foot. Results: We found that both FDL and FHL transfers have biomechanical advantages and disadvantages. Neither of these transfers decrease the stress on the tibialis posterior tendon if the underlying pathologies such as spring ligament failure are not addressed. Conclusions: Of the tendon transfers evaluated, FDL transfer to the navicular had the most profound effect on reducing the stresses on the spring ligament.

The clinical disorder traditionally known aspes planovalgus due to posterior tibial tendon insufficiencyoradult-acquired pes planovalgushas been the subject of several publications over the past two decades. Now, it is understood that the problem does not lie in the posterior tibial tendon per se and may even occur without tendon injury. Studies have brought new concepts and understanding that question the views on this subject, culminating in the replacement of existing classifications with one that is more assertive and discriminative of the potential presentation patterns of the deformity. In addition, a change in the name of the disorder toprogressive collapsing foot deformity(PCFD) has been proposed.Regarding surgical treatment, the concept of anà la carteapproach persists, emphasizing axis realignment through osteotomies, arthrodeses, and soft tissue balancing, which consists of tendon transpositions/repairs and reconstruction of ligament structures, especially the deltoid ligament complex and the spring ligament.

The use of computational models of the human foot based on finite element analysis offers a promising alternative for understanding the biomechanical internal changes of this structure. However, the evaluation of dynamic scenarios has been challenging. This research aims to design a computational model that accurately simulates foot biomechanics during the stance period of the gait cycle in healthy and flatfoot scenarios. The model is focused on analyzing stress variations in soft tissues such as the plantar fascia and spring ligament to provide valuable insights into the internal biomechanics of the foot. The results were evaluated using maximum principal stress. Validation was performed by measuring clinical angles and comparing the range of motion of foot joints with known values for each phase. Results show that the plantar fascia and spring ligament stress increase during the second and third rockers compared to the first rocker. Additionally, as was expected, flatfoot simulations show stress increments in those evaluated soft tissues, while surgical treatment scenarios contributed to stress reduction in these regions. These findings emphasize the active role of the plantar fascia and spring ligament, particularly during approximately 50% of the stance period when the plantar arch deformity is greater. Results show valuable insights into the internal biomechanics of the foot through computational models.