BACKGROUND:The deltoid-spring ligament complex (DSL) is recognised as an integrated stabilising structure of the ankle-hindfoot complex; however, the relative contributions of its individual components to talonavicular joint (TNJ) stability remain incompletely defined. While the tibiocalcaneal (TC) fibres are known to influence ankle and subtalar mechanics, their role in TNJ abduction stability has not previously been experimentally assessed. PURPOSE:To quantify the contribution of the tibiocalcaneal fibres to talonavicular joint abduction stability (primary outcome, degrees) and hindfoot eversion (secondary outcome, millimetres), and to compare their effect with that of other DSL components using a paired cadaveric sectioning model. METHODS:Eighteen embalmed cadaveric lower limbs were tested under controlled, non-weight-bearing conditions. Specimens were randomised to anterior-posterior or posterior-anterior sequential sectioning of the tibionavicular, tibiospring, spring, and tibiocalcaneal fibres. Changes in TNJ abduction and hindfoot eversion were recorded following isolated and sequential ligament sectioning. The primary comparison was the effect of isolated tibiocalcaneal sectioning versus isolated tibionavicular and tibiospring sectioning on TNJ abduction. RESULTS:Sequential DSL sectioning resulted in significant, stepwise increases in TNJ abduction and hindfoot eversion (p < 0.05). Isolated sectioning of the tibiocalcaneal fibres produced greater TNJ abduction than isolated tibionavicular or tibiospring sectioning. Across protocols, the tibiocalcaneal fibres accounted for approximately 28-40% of total TNJ abduction stability. Hindfoot eversion increased progressively with ligament disruption, reflecting combined tibiotalar and subtalar contributions. CONCLUSIONS:Tibiocalcaneal fibres contribute substantially to talonavicular joint abduction stability despite not directly spanning the joint. These findings support the concept of integrated medial ligament function and provide biomechanical insight to inform future experimental and modelling studies of ankle-hindfoot stability.

The obliquity of the first metatarsocuneiform joint has long been proposed as a contributing factor in the development of hallux valgus (HV). Several studies have evaluated the medial slope of the distal articular surface of the medial cuneiform relative to its longitudinal axis, commonly described as the distal medial cuneiform angle (DMCA). An increased DMCA has been hypothesized to predispose individuals to HV by altering first-ray biomechanics. The objective of this study is to conduct a systematic review of the literature to determine whether DMCA is a significant risk factor for the development of HV. A systematic literature search was conducted across Ovid, Embase, MEDLINE, and PubMed databases on February 8, 2025, identifying studies published between January 2004 and December 2024. Searches used predefined MeSH terms, including obliquity, angulation, and medial cuneiform, followed by combined-term analysis. English-language full-text articles were screened, and reference lists were reviewed for additional studies. Eligible studies compared DMCA measurements between HV and control cohorts. Where appropriate, pooled effect sizes were calculated using Hedges' g. The review identified a limited number of heterogeneous observational studies evaluating DMCA in HV populations. Meta-analytic synthesis demonstrated a small but statistically significant association between increased DMCA and HV (Hedges' g = 0.19, p = 0.01). However, substantial variability was noted in measurement techniques, radiographic positioning, and definitions of HV severity, limiting comparability across studies. Current evidence demonstrates a statistically significant but small association between increased DMCA and HV. The modest effect size suggests that DMCA alone is unlikely to be a dominant causal factor and should be considered within a multifactorial biomechanical framework. Further high-quality, standardized studies are required to clarify the clinical relevance of DMCA in the pathogenesis of HV.

BACKGROUND:Open calcaneal fractures are rare, high-energy injuries involving extensive soft-tissue loss and comminuted bone disruption. Successful management depends on coordinated orthoplastic reconstruction to achieve stable fixation and durable coverage. Multiple flap types have been described, yet comparative outcomes remain poorly defined. METHODS:A systematic review was performed in accordance with PRISMA guidelines (PROSPERO: CRD420251138394). MEDLINE, Embase, Cochrane CENTRAL, and Scopus were searched from January 2000 to July 2025. Studies reporting flap-based reconstruction for open calcaneal fractures in adults were included. Extracted data included flap type, fixation method, follow-up duration, and complications such as infection, necrosis, vascular crises, flap loss, and amputation. RESULTS:Thirteen studies comprising 88 major flap reconstructions were analysed. Overall flap survival was 97.7%, with two failures (both muscle/myocutaneous). Fasciocutaneous flaps showed the lowest complication rates (8.3%) with no reported cases of infection, while muscle/myocutaneous flaps demonstrated cases of infection (20%) and accounted for both flap failures and the only reported amputation. Chimeric flaps were increasingly used in recent series (n = 32), achieving reliable survival but higher vascular compromise (6.3%). Osteocutaneous flaps were rare (n = 4) and primarily used for defects with bone loss, showing infection in 50% of cases. Meta-analysis was not possible due to heterogeneity and small sample sizes. CONCLUSIONS:Fasciocutaneous flaps provide reliable, low-complication coverage for clean wounds, while muscle flaps remain valuable for contamination or complex cases with extensive tissue loss. Chimeric, and osteocutaneous flaps show promise, but larger, standardised studies are needed to clarify their roles in hindfoot reconstruction.

INTRODUCTION:Calcaneal fractures present significant treatment challenges due to their complex anatomy and load-bearing function. Increasingly, minimally invasive techniques are used in treatment. This study evaluates the biomechanical performance of 3 different fixation methods using embalmed cadaver calcanei subjected to a controlled linear increase in load. METHODS:18 cadaveric calcanei were dissected and a simulated Sanders IIB joint depression calcaneal fracture was created with a saw. The fixation techniques used were: plate and 6.5 mm longitudinal screws, plate alone, and screws alone. Biomechanical testing was conducted using a uniaxial loading machine to assess stability, load transmission, and fragment displacement characteristics. RESULTS:There was no statistically significant difference in the force/energy to failure between fixation types. Plate fixation did not result in any displacement of the fracture fragments in all specimens tested. Failure of fixation occurred in both screw fixation and plate with screw fixation, predominantly affecting the anterior process. CONCLUSIONS:In this cadaver model, minimally invasive techniques provide similar stability of fracture fixation with uniaxial loading to plate fixation, however further consideration of fixation of the anterior process may be required with minimally invasive techniques.

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 progressive ligament instability associated with flatfoot deformity may result in altered foot biomechanics and represent a risk factor for the development of Achilles Tendinopathy (AT). The aim of this study was to determine whether an increased tendo-Achilles (TA) force was required to generate a set heel lift in a cadaveric flatfoot model. Thirteen fresh (previously frozen) cadavers, with no previous foot pathology and sectioned from the knee were mounted on a testing frame. The frame maintained a dorsiflexed ankle position, to simulate the terminal stance phase of gait, and allowed a constant axial load to be applied through the tibia. The heel was elevated 3 cm by a measured traction force through the TA to a pre-determined laser mark. The flatfoot model was created by sequential sectioning of the medial arch supporting structures, creating progressive midfoot instability and flatfoot deformity, from mild to severe. The force (N) required to generate heel lift was recorded at each stage of the development of the flatfoot. Initially, following Spring ligament and Tibialis Posterior sectioning, the force required to generate heel lift decreased. However, as the flatfoot deformity progressed the force required for heel lift increased. A severe flat foot deformity, characterised by medial ray destabilisation significantly increased the force required to generate a heel lift (5.1 ± 7.2 N, p = 0.02) as did sectioning of the (ii) short and long plantar ligaments (5.5 ± 8.7 N, p = 0.03). Progressive ligament failure associated with acquired flatfoot deformity may be a risk for AT overload due to increased TA force required for heel lift, resulting in TA overload symptoms. The paradoxical decrease in force required to generate heel lift with isolated SL sectioning has not been previously described. This biomechanical study raises the possibility that interventions that support the medial longitudinal arch, such as orthotics, may protect against TA overload.

The aim of this study is to review the 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 bands in the English language and 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.

Bilateral, simultaneous ruptures of the knee extensor mechanism, involving either the quadriceps tendon or the patellar tendon, represent uncommon injuries which are often associated with specific predisposing risk factors. In this, the largest retrospective series yet published, we present 12 cases of extensor mechanism rupture. Medical records across four hospitals in East Anglia were reviewed, identifying eight cases of bilateral quadriceps tendon rupture, two of bilateral patellar tendon rupture and two of asymmetric injury, with rupture of the quadriceps on one side and the patellar tendon on the other. Data was collected on mechanism of injury, patient demographics, risk factors and surgical repair techniques utilised The mean age of patients was 60.6 years (range 39 to 77). Patients with bilateral quadriceps tendon rupture were older (mean 62.5 years) than patients with bilateral patellar tendon rupture (mean 44.5 years). Type 2 Diabetes Mellitus and smoking were the most common medical risk factors, affecting two patients each. Eight patients underwent a transosseus suture repair, two a direct suture repair, one a direct suture repair augmented by cerclage wiring. In the immediate post-operative period, seven had their range of movement restricted in a hinged knee brace, and four were immobilised in a cast. One patient lacked operative data. A high index of suspicion is required to diagnose knee extensor mechanism injuries. We recommend as part of the consenting process counselling on modifiable risk factors which increase the likelihood of rupture and pose intra-operative and post-operative challenges.

Background: Classifications of AAFD/PCFD have evolved with an increased understanding of the pathology involved. A review of classification systems helps identify deficiencies and respective contributions to the evolution in understanding the classification of AAFD/PCFD. Methods: Using multiple electronic database searches (Medline, PubMed) and Google search, original papers classifying AAFD/PCFD were identified. Nine original papers were identified that met the inclusion criteria. Results: Johnson’s original classification and multiple variants provided a significant leap in understanding and communicating the pathology but remained tibialis posterior tendon-focused. Drawbacks of these classifications include the implication of causality, linearity of progression through stages, an oversimplification of stage 2 deformity, and a failure to understand that multiple tendons react, not just tibialis posterior. Later classifications, such as the PCFD classification, are deformity-centric. Early ligament laxity/instability in normal attitude feet and all stages of cavus feet can present with pain and instability with minor/no deformity. These may not be captured in deformity-based classifications. The authors developed the ‘Triple Classification’ (TC) understanding that primary pathology is a progressive ligament failure/laxity that presents as tendon reactivity, deformity, and painful impingement, variably manifested depending on starting foot morphology. In this classification, starting foot morphology is typed, ligament laxities are staged, and deformity is zoned. Conclusions: This review has used identified deficiencies within classification systems for AAFD/PCFD to delink ligament laxity, deformity, and foot type and develop the ‘Triple classification’. Advantages of the TC may include representing foot types with no deformity, defining complex secondary instabilities, delinking foot types, tendon reactivity/ligament instability, and deformity to represent these independently in a new classification system. Level of Evidence: Level V.

BACKGROUND:Calcaneal fractures remain a big challenge in orthopaedic surgery and lead to long lasting disabilities. Cadaveric research plays an important role in determining optimal fracture treatment. This scoping review aims to provide insight into cadaveric research that has been conducted on calcaneal fractures, including biomechanics, fixation, approaches and radiographic studies.METHODOLOGY:A search strategy was created and implemented as per PRISMA guidance. 3 databases, Medline, Embase and Scopus, were used when conducting this review.RESULTS:484 individual studies were retrieved across the 3 databases, of which 186 duplicates were excluded. Study abstracts were individually reviewed, of which 208 studies were excluded in accordance with study criteria. 90 papers were sought for retrieval, of which 83 full text papers were successfully retrieved. Of the full papers retrieved, 22 did not meet our inclusion criteria, and 19 papers related only to talus fractures. In the end, 43 cadaveric studies pertaining to this scoping review were included and reviewed.DISCUSSION:Studies were grouped into biomechanical, anatomical, fixation and radiographic studies for review.CONCLUSION:Evaluation of current cadaveric studies pertaining to calcaneal fractures has allowed greater insight into the myriad challenges in the management of these injuries. Effects of intra-articular fractures on calcaneal biomechanics assist in establishing surgical goals. Whilst fixation studies showing good stability of nail fixations could encourage further development in minimally invasive techniques. Avoiding pitfalls seen in the extensile lateral approach. Recommendations of areas for further research include use of external fixators, fixation in non-Sanders Type 2 fractures, and comparison of intraoperative CT/3D fluoroscopy with o conventional fluoroscopy.

Introduction First Ray Instability (FRI) and especially hypermobility leads to the collapse of the medial longitudinal arch's structural framework, which reduces the foot's ability to become a rigid lever for propulsion, resulting in progressive foot deformities. Early detection of FRI with prompt intervention helps prevent degenerative foot deformities. Various manual, device-based and radiographic diagnostic tests for FRI quantification have been described in the literature. We aim to conduct an up-to-date, comprehensive, systematic review of the literature reporting on diagnostic tests to evaluate FRI. Methodology Electronic databases (Medline, Embase and PubMed) and bibliography lists were searched until May 2021 for studies evaluating diagnostic tests for FRI. MeSH terms were used to conduct the literature search. The authors screened all produced abstracts. Selected articles were further assessed in full based on inclusion and exclusion criteria. The relevant studies were qualitatively assessed and grouped into tables based on tests. Results 18,176 studies were identified. Thirty-two full-text articles were included for assessment. Ten articles were excluded based on evaluation criteria. 18 studies were included for qualitative assessment: two studies describing manual diagnostic tests, three evaluating device-driven tests, six image-guided studies and seven comparison studies assessing a new test versus an established one. Conclusion Gold standard tests in defining FRI need to be improved. Manual tests exhibit significant subjective variability. Radiographic tests, while accurate, are complex and cumbersome to perform and, therefore, are not widely applied. Dorsal rulers have demonstrated mixed results and shown variability when compared to instruments. The focus has been on assessing FRI in hallux valgus (HV). More studies are needed to investigate FRI in the absence of HV.

BackgroundTalar neck fractures are rare but potentially devastating injuries, with early reduction and rigid fixation essential to facilitate union and prevent avascular necrosis. Even small degrees of malunion will alter load transmission and subtalar joint kinematics. Changes in fixation techniques have led to dual plating strategies. While locked plating has perceived advantages in porotic bone and comminution, its biomechanical benefits have not been proven.AimTo compare the strength of locking vs. non-locking plate fixation in comminuted talar neck fractures.MethodSeven pairs of cadaveric tali were randomised to locking or non-locking plate fixation. A standardised model of talar neck fracture with medial comminution was created, and fixation performed. The fixed specimens were mounted onto a motorised testing device, and an axial load applied.ResultsPeak load to failure, deformation at failure, work done to achieve failure, and stiffness of the constructs were measured. No statistically significant difference was found between locking and non-locking constructs for all parameters.ConclusionsBoth constructs provide similar strength to failure in talar neck fracture fixations. Mean peak load to failure did not exceed the theoretical maximum forces generated of 1.1 kN when weight-bearing. We would advocate caution with early mobilisation in both fixations.

Cuboid navicular coalition (CN) is a rare type of osseous, cartilaginous, or fibrous congenital bridge arising from failure of differentiation of more than two tarsal bones. We report the first reported case of a 36-year-old male presenting with a calcaneus fracture associated with an osseous CN coalition with no prior coalition symptoms. CT and MRI demonstrated unusual fracture patterns extending into the middle facet with a middle facet and talonavicular subluxation. Initial emergency talonavicular reduction and delayed calcaneal open reduction and internal fixation (ORIF) was undertaken. The coalition was not excised as there were no prior coalition symptoms. This is the first reported case presentation of a rare CN osseous coalition presenting with a calcaneal fracture. Variations in presentation of calcaneal fractures may allude to the presence of a coalition requiring careful consideration of both pathologies when considering treatment.

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 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 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 laxity and first ray instability in all ATR feet (p<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 helps 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.

Adult-acquired flatfoot has been considered to arise from tibialis posterior tendon deficiency. Recent evidence shows that arch stability is mainly maintained by structures such as plantar fascia and spring ligament. The dysfunction of these ’passive’ stabilizers results in loss of arch integrity that causes forefoot pronation and reactive tendon overload, especially in the tibialis posterior tendon and peroneus longus tendon. The peroneus longus tendon (PLT) spans several midfoot joints and overloads with arch lengthening. The biomechanical stress/changes that occurs in this tendon are not well recognized. This study evaluates the biomechanical consequences that fusions have on peroneus longus tendon stresses in soft-tissue deficiencies associated with flatfoot deformity. A complete computational human foot model was used to simulate different scenarios related to the flatfoot deformity and associated common midfoot/hindfoot fusions, to quantify the biomechanical changes in the peroneus longus tendon. The results showed that the stress of the peroneus longus tendon is especially affected by the fusion of hindfoot joints and depends on the soft tissue types that fail, causal in generating the flatfoot. These results could be useful to surgeons when evaluating the causes of flatfoot and the secondary effects of surgical treatments on tissues such as the peroneus longus tendon.

Adult acquired flatfoot deformity (AAFD) involves a complex spectrum of pathologies, arising primarily from failure of static restrains, leading to collapse of the medial longitudinal arch and further subsequent deformities in the foot. The landmark paper and classification by Johnson et al. proposed that pathology in the posterior tibial tendon (PTT) was key in the development of AAFD. Since then, the understanding of AAFD has evolved and advanced. Multiple structures aside from the PTT, such as the spring ligament, plantar fascia and deltoid ligament, have been identified to play a similarly key role in disease development and progression. Classification systems have also evolved to incorporate this new understanding. These include modifications to Johnson's classification (Myerson, Bluman) as well as new systems which aim to incorporate modern thinking, capture the wide spectrum of presentations or utilize modern advancements in imaging modalities. Current classification systems continue to aid understanding and management of AAFD, despite their increasing complexity. Future classifications should aim to provide a succinct way to describe and understand AAFD, as well as guiding prognosis and management.

AAFD comprises ligamentous failure and tendon overload, mainly focused on the symptomatic posterior tibial tendon and the spring ligament. Increased lateral column (LC) instability arising in AAFD is not defined or quantified. This study aims to quantify the increased LC motion in unilateral symptomatic planus feet, using the contralateral unaffected asymptomatic foot as an internal control. In this case matched analysis, 15 patients with unilateral stage 2 AAFD foot and an unaffected contralateral foot were included. Lateral foot translation was measured as a guide to spring ligament competency. Medial and LC dorsal sagittal instability were assessed by direct measurement of dorsal 1st and 4th/5th metatarsal head motion and further video analysis. The mean increase in dorsal LC sagittal motion (between affected vs unaffected foot) was 5.6 mm (95% CI [4.63–6.55], p < 0.001). The mean increase in the lateral translation score was 42.8 mm (95% CI [37.48–48.03], p < 0.001). The mean increase in medial column dorsal sagittal motion was 6.8 mm (95% CI [5.7–7.8], p < 0.001). Video analysis also showed a statistically significant increase in LC dorsal sagittal motion between affected and unaffected sides (p < 0.001). This is the first study that quantifies a statistically significant increased LC dorsal motion in feet with AAFD. Understanding its pathogenesis and its link to talonavicular/spring ligament laxity improves foot assessment and may allow the development of future preventative treatment strategies.

•Modified application of heel external rotation test detects deep deltoid instability in AAFD.•Spring ligament sectioning causes non-significant increase in tibiotalar external rotation.•Deep deltoid is the only medial ligament, when sectioned, to cause significant tibiotalar external rotation.

Lateral column (LC) instability occurs in adult acquired flatfoot deformity (AAFD). Differential ligament contribution to LC stability is unknown. The primary aim was to quantify this by using cadaver sectioning of lateral plantar ligaments. We also determined the relative contribution of each ligament to dorsal translation of the metatarsal head in the sagittal plane.

Classifications of AAFD/PCFD have evolved with an increased understanding of the pathology involved. A review of classification systems helps identify deficiencies and respective contributions to the evolution in understanding the classification of AAFD. Using multiple electronic database searches (Medline, PubMed) and Google search, original papers classifying AAFD were identified. Nine original articles were identified that met the inclusion criteria. Johnson's original classification and multiple variants provided a significant leap in understanding and communicating the pathology but remained tibialis posterior tendon focussed. Drawbacks of these classifications include the implication of causality, linearity of progression through stages, an over-simplification of stage 2 deformity and a failure to understand multiple tendons react, not just tibialis posterior. Later classifications, such as the PCFD classification, are deformity-centric. Early instability in non-cavus feet and all stages of cavus feet can present pain and instability with minor/no deformity. These may not be captured in deformity-based classifications biased to planus feet.' The authors developed the 'Triple Classification' (TC) understanding that primary pathology is a progressive ligament failure/instability that presents as tendon reactivity, deformity, and painful impingement. There is a variable manifestation dependent on starting foot morphology. This review has identified deficiencies within classification systems used in AAFD/PCFD and, as a result, was used to help develop a more comprehensive 'Triple classification'. Advantages of the TC include representing foot types with no deformity, defining complex secondary instabilities, delinking of foot types, tendon reactivity/ligament instability and deformity to represent these independently in a more comprehensive classification system.