Acquired adult flat foot due to isolated plantar calcaneonavicular (spring) ligament insufficiency with a normal tibialis posterior tendon

Advancing Adult-Acquired Flatfoot Deformity Treatment: Enhanced Biomechanical Support Through Graphene Oxide-Integrated Bioengineered Grafts Tested In Silico

Adult-Acquired Flatfoot Deformity (AAFD) is a progressive orthopedic condition causing the collapse of the foot's medial longitudinal arch, often linked with injuries to the plantar arch's passive stabilizers, such as the spring ligament (SL) and plantar fascia. Conventional treatment typically involves replacing the SL with synthetic material grafts, which, while providing mechanical support, lack the biological compatibility of native ligaments. In response to this shortcoming, our study developed an electrospun, twisted polymeric graft made of polycaprolactone (PCL) and type B gelatin (GT), enhanced with graphene oxide (GO), a two-dimensional nanomaterial, to bolster biomechanical attributes. The addition of GO aimed to match the native ligamentous tissue's mechanical strength, with the PCL-GT-GO 2.0% blend demonstrating an optimal Young's modulus of 240.75 MPa. Furthermore, the graft showcased excellent biocompatibility, evidenced by non-hemolytic reactions, suitable wettability and favorable platelet aggregation-essential features for promoting cell adhesion and proliferation. An MTT assay revealed cell viability exceeding 80% after 48 h of exposure, highlighting the potential of the graft as a regenerative scaffold for affected ligaments. Computational modeling of the human foot across various AAFD stages assessed the graft's in situ performance, with the PCL-GT-OG 2.0% graft efficiently preventing plantar arch collapse and offering hindfoot pronator support. Our study, based on in silico simulations, suggests that this bioengineered graft holds significant promise as an alternative treatment in AAFD surgery, marking a leap forward in the integration of advanced materials science for enhanced patient care.

Spring Ligament Reconstruction for Progressive Collapsing Foot Deformity: Contemporary Review

The spring ligament is one of the main stabilizers of the medial arch of the foot and the primary static supporter of the talonavicular joint. Attenuation or rupture of this ligament is thought to play a central role in the pathophysiology of progressive collapsing foot deformity. Traditional correction of flexible flatfoot consists of posterior tibial tendon augmentation along with various osteotomies or hindfoot fusions. Repair or reconstruction of the spring ligament has not been as widely pursued. In recent years, newer techniques have been explored and may improve outcomes of traditional procedures, or possibly entirely replace some osteotomies. Combined spring-deltoid ligament reconstruction is also gaining traction as a viable technique, particularly as the ankle begins to deform into valgus. This review summarizes the variety of nonanatomic and anatomic reconstruction techniques that have been described, including autologous tendon transfers, allografts, and synthetic augmentation. Although many have only been characterized in biomechanical cadaver studies, this article reviews preliminary clinical studies that have shown promising results. There is a need for more high-quality studies evaluating the clinical, radiographic, and patient-reported outcomes following spring ligament reconstruction.

Ligament Insufficiency with Flatfoot: Spring Ligament and Deltoid Ligament

The objective of this article was to review the deltoid ligament and spring ligament specifically as they pertain to ligament insufficiency and adult-acquired flatfoot deformity. Discussion includes the normal and abnormal biomechanical forces that extend through these ligaments in normal and flatfoot deformity. Current literature related to spring ligament repair as part of the flatfoot deformity reconstruction is also reviewed.

The Potential of Endoscopic Spring Ligament Repair in Flatfoot Reconstruction

BACKGROUND

Spring ligament fulfills 2 main important functions: one, supporting the head of the talus and stabilizing the talonavicular joint, and the other, maintaining the longitudinal arch by acting as a static support. In this preliminary report, we describe an endoscopic repair for spring ligament injuries with modified portals.

METHODS

We performed a retrospective case series study from February 2019 to January 2022. Posterior tibial tendon and/or associated bone deformities were assessed at the same surgical procedure. All patients were ≥18 years old and they had more than 6 months of follow-up. The procedure was performed in 11 patients. Mean age was 46 years (range 18-63). Ten had concomitant bony realignment surgery, and 8 had posterior tibial tendon surgery.

RESULTS

In all patients, endoscopic spring ligament repair could be technically done. The modified portals were used in all procedures as described in the surgical technique. Three patients had a superficial lesion, 1 had a rupture <5 mm, 7 had a rupture >5 mm but not a complete rupture through the entire spring ligament. Most of the patients had good clinical results from the surgery that included endoscopic spring ligament debridement and/or repair at 2 years follow up.

CONCLUSION

In this small series we found that endoscopy may be an effective technique to diagnose and treat incomplete spring ligament injuries.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Seguridad de los portales para la reparación endoscópica del ligamento calcaneonavicular: estudio cadavérico

Introducción: La lesión del ligamento calcaneonavicular ha sido descrita como una de las causas de la deformidad en el pie plano del adulto. El objetivo de este artículo es describir portales modificados para el diagnóstico y la reparación endoscópica de las lesiones del fascículo superomedial del ligamento calcaneonavicular y evaluar la seguridad de los portales utilizados. Materiales y Métodos: Se llevó a cabo un estudio cadavérico con seis preparados reproduciendo una lesión del fascículo superomedial del ligamento calcaneonavicular con una punta de corte de radiofrecuencia y la posterior reparación endoscópica. Se crearon dos portales modificados para el abordaje. Luego se procedió a la disección anatómica para evaluar la seguridad de los portales en relación con las estructuras anatómicas. El primer portal se realiza inmediatamente proximal a una línea trazada desde la punta del maléolo medial dirigida al centro del talón, el segundo portal se emplaza 0,5 cm proximal a la inserción del tendón tibial posterior en el escafoides por transiluminación. Si es necesario, se coloca un portal accesorio inmediatamente dorsal al tendón tibial posterior a mitad de camino entre los dos portales antes descritos. Resultados: En todos los casos, fue posible la reparación del ligamento con el procedimiento endoscópico. En la disección anatómica de los portales, se observó una distancia promedio a las estructuras vasculonerviosas de 11,83 mm del portal proximal y de 9,66 mm del portal distal. Conclusión: Los portales modificados son seguros y permiten la visualización directa del haz superomedial del ligamento calcaneonavicular y su reparación endoscópica.

The Effect of Progressive Lateral Column Lengthening in a Novel Stage II-B Flatfoot Cadaveric Model Evaluated Using Software-Guided Radiographic Measurements of Foot Alignment

BACKGROUND

This work used software-guided radiographic measurement to assess the effects of progressive lateral column lengthening (LCL) on restoring alignment in a novel cadaveric model of stage II-B flatfoot deformity.

METHODS

A stage II-B flatfoot was created in 8 cadaveric specimens by transecting the spring ligament complex, anterior deltoid, and interosseous talocalcaneal and cervical ligaments. Weightbearing computed tomographic (WBCT) scans were performed with specimens under 450 N of compressive load in the intact, flat, and 6-, 8-, and 10-mm lateral column-lengthening conditions. Custom software-guided radiographic measurements of the lateral talo-first metatarsal (Meary) angle, anteroposterior talo-first metatarsal angle, naviculocuneiform overlap, and 2 new measures (plantar fascia [PF] distance and angle) were recorded on digitally reconstructed radiographs. Four anonymized analysts performed measurements twice. Intra- and interobserver agreement was assessed using intraclass correlation coefficients (ICCs).

RESULTS

Six-millimeter LCL restored alignment closest to the intact foot in this new cadaveric model, whereas 10-mm lengthening tended toward overcorrection. The PF line displaced laterally in the flatfoot condition, and LCL restored the PF line to a location beneath the talonavicular joint. Interobserver agreement was excellent for PF distance (ICC = 0.99) and naviculocuboid overlap (ICC = 0.91), good for Meary angle (ICC = 0.81) and PF angle (ICC = 0.69), and acceptable for the talonavicular coverage angle (ICC = 0.65).

CONCLUSION

In this stage II-B cadaveric flatfoot model, cervical ligament transection was essential to create deformity after the medial hindfoot ligaments were transected. Software-guided radiographic measurement proved reliable; standardized implementation should improve comparability between studies of flatfoot deformity. The novel PF distance performed most consistently (ICC = 0.99) and warrants further study. With this model, we found that a 6-mm LCL restored alignment closest to the intact foot, whereas 10-mm lengthening tended toward overcorrection.

CLINICAL RELEVANCE

Future joint-sparing flatfoot corrections may consider using a relatively small LCL combined with other bony and/or anatomic ligament/tendon reconstructions.

A Critical Biomechanical Evaluation of Foot and Ankle Soft Tissue Repair

The objective of this article is to review the biomechanical stresses that occur during normal physiologic function of lower extremity soft tissue anatomic structures and to use this as a baseline for a critical analysis of the medical literature because it relates to surgical reconstruction following injury. The Achilles tendon, anterior talofibular ligament, plantar plate, and spring ligament are specifically evaluated.

Injuries to the Spring Ligament: Nonoperative Treatment

The fibrocartilage within the superomedial calcaneonavicular (spring) ligament is part of an interwoven complex of ligaments that span the ankle, subtalar, and talonavicular joints. Acute isolated rupture of the spring ligament has been reported in association with an eversion ankle sprain. Attenuation and failure of the spring ligament causes complex 3D changes called the progressive collapsing foot deformity (PCFD). This deformity is characterized by hindfoot eversion, forefoot supination, collapse of the medial longitudinal arch, and forefoot abduction. Nonoperative treatment of an isolated spring ligament rupture and PCFD using various designs of orthoses have shown promising results.

How does the postoperative medial arch height influence the patient reported outcomes of stage Ⅱ acquired adult flatfoot deformity?

BACKGROUND

This study aimed to assess how the postoperative medial arch height influenced postoperative patient-reported clinical outcomes after surgery for stage Ⅱ acquired adult flatfoot deformity.

METHODS

A total of 30 feet of 30 patients (7 males, 23 females) who underwent surgery for stage Ⅱ acquired adult flatfoot deformity and could be followed up for at least 2 years were included. The average age at surgery was 60.0 (standard deviation, 13.0) years, and the average follow-up period was 40 (standard deviation, 15.4) months. Among them, 16 patients underwent lateral column lengthening and 14 patients did not. Patient-reported clinical outcomes were evaluated using the Self-Administered Foot Evaluation Questionnaire. Radiographic alignment was evaluated by the talonavicular coverage angle, lateral talo-1st metatarsal angle, medial cuneiform height, medial cuneiform to 5th metatarsal height, and calcaneal pitch. The correlation between postoperative Self-Administered Foot Evaluation Questionnaire and radiographic alignment was assessed with Pearson's correlation analysis.

RESULTS

Self-Administered Foot Evaluation Questionnaire and radiographic alignment significantly improved postoperatively in all patients (P < 0.0001). In patients with severe deformity who needed lateral column lengthening, lateral talo-1st metatarsal angle was negatively and medial cuneiform to 5th metatarsal height was positively correlated with physical functioning Self-Administered Foot Evaluation Questionnaire subscales (r = -0.56 and 0.55), and medial cuneiform height was positively correlated with physical functioning, social functioning and general health Self-Administered Foot Evaluation Questionnaire subscales (r = 0.70, 0.55 and 0.73, respectively).

CONCLUSION

Postoperative medial arch height could influence physical functioning, social functioning, and general health in patients with severe stage II adult-acquired flatfoot deformity.

Outcomes of 2B Adult Acquired Flatfoot Deformity Correction in Patients With and Without Spring Ligament Tear

BACKGROUND

It is currently unclear how injury to the spring ligament (SL) affects the preoperative presentation of adult acquired flatfoot deformity (AAFD) or the outcome of operative reconstruction. The purposes of this study were to assess the preoperative features and pre- or postoperative function of patients who underwent direct operative repair of an SL tear compared to those without a tear.

METHODS

86 patients undergoing operative correction of grade 2B AAFD by a single fellowship-trained foot and ankle orthopaedic surgeon were reviewed at an average follow-up of 45.9 months. There were 35 feet found to have an SL tear that underwent concomitant debridement and direct repair of the SL. Patient charts were reviewed for demographic information, preoperative visual analog scale (VAS) pain level, and their Foot and Ankle Ability Measure (FAAM) activities of daily living (ADL) and sports subscales. Preoperative radiographic parameters were assessed. Patient outcomes of VAS pain, FAAM-ADL, and FAAM-Sports were collected and compared between groups.

RESULTS

Those with an SL tear had significantly lower FAAM-ADL and sports scores, with higher VAS pain scores preoperatively. Patient age, talonavicular uncoverage percentage, and talonavicular angle were found to be associated with spring ligament degeneration. At final follow-up, patients demonstrated a significant improvement in all outcome parameters, with no statistical difference found with patient satisfaction, final postoperative VAS pain, FAAM-ADL, or FAAM-Sports in those requiring a repair of their SL as compared to the control group.

CONCLUSION

Increasing patient age, increasing talonavicular uncoverage percentage, and decreasing talonavicular angle are all independently associated with increased likelihood of patients with AAFD having an SL tear. At follow-up for operative treatment of grade 2B AAFD flatfoot with our approach, we found no clinical outcomes difference between those without SL tears and those with SL tears treated with concomitant SL debridement and repair.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Spring and Deltoid Ligament Insufficiency in the Setting of Progressive Collapsing Foot Deformity. An Update on Diagnosis and Management

The spring ligament and deltoid ligament are important stabilizers of the medial ankle. Together, they form a complex along the medial ankle and foot that is critical to stability of both the ankle and the medial longitudinal arch. Incompetence of the spring and deltoid ligament is a component of both the early and late stages of progressive collapsing foot deformity. As the importance of this medial ligament complex has been recognized, repair and reconstruction of these ligaments have progressively evolved, initially as separate reconstructions, and more recently as combined techniques.

What Are the Updates on Epidemiology of Progressive Collapsing Foot Deformity?

Progressive collapsing foot deformity is one of the most controversial topics in foot and ankle surgery. Much research has been done regarding anatomy, biomechanics, and etiology behind this complex deformity and there is interest in studying metabolic or genetic conditions that could influence the development of this multifactorial disorder. Relevant anatomy includes osseous and soft tissue structures. Several risk factors like obesity, genetics, and flat foot during childhood have been proposed in literature. It occurs 3 times more often in women, the peak incidence happening at age 55, and is more common in white, obese, diabetic, rheumatic, and hypertensive patients.

Current Trends in Treatment of Injuries to Spring Ligament

The spring ligament is the main static supporter of the medial longitudinal arch. Identifying every detail of the pathophysiology of each condition in which these structures are involved is the key to an appropriate approach and treatment. Isolated reconstruction of the posterior tibial tendon present long-term results with a high failure rate. It is important to diagnose spring ligament injuries because of the probable consequences if not treated, such as acquired flatfoot deformity and loss of correction of treated flatfoot. The option of surgical treatment is discussed in this article.

Anatomy of the Deltoid-Spring Ligament Complex

A thorough knowledge of the anatomy of the deltoid and spring ligament complex is important for treatment of deformities that impact the foot and ankle. Both ligaments are interconnected, and the study of their anatomic characteristics is better performed together than in isolation. The deltoid ligament is a group of ligaments that derives its origin from the medial malleolus, and the spring ligament complex consist of a group of ligaments that connects the navicular and the sustentaculum tali of the calcaneus. They both play an important role in stabilization of the medial ankle and medial column of the foot.

Flatfoot Deformity Due to Isolated Spring Ligament Injury

Patients with acquired flatfoot deformity due to isolated injury of the spring ligament, with healthy posterior tibialis tendon, are rarely identified. Between December 2004 and September 2011 (6 years and 9 months), we treated 10 patients with acquired flatfoot deformity due to spring ligament injury without tibialis posterior tendon tear. One patient (10%) was lost to follow-up. The mean age of the patients was 44.33 ± 12.91 years; 4 (44.4%) were female, and 5 (55.56%) were male. Clinical presentation included mild to moderate hindfoot valgus and pain extending from the inferior part of the medial malleolus to the navicular, inferior to tibialis posterior. Forefoot abduction was not always present. Weightbearing radiographs and magnetic resonance imaging (MRI) scans were obtained in all cases. Six patients (66.66%) of the patients had a history of minor trauma. Spring ligament repair was performed in all cases, and 4 patients (44.44%) underwent adjunct procedures. After surgery, a cast was applied, and weightbearing was avoided for 6 weeks. The mean preoperative American Orthopaedic Foot and Ankle Society (AOFAS) score was 39.66 ± 18.55, and this improved to 84.88 ± 12.41 after surgery (p = .023). No statistically significant differences were found between males and females or between isolated repairs and adjunct procedures. The mean duration of follow-up was 45.33 ± 37.11 months (range 15 to 120), and no complications were identified. Isolated injuries of the spring ligament with normal posterior tibialis tendon are rarely described and may be more prevalent than generally appreciated.

High incidence of spring ligament laxity in ankle fractures with complete deltoid ruptures and secondary first ray instability

AIMS

To assess the incidence of spring ligament failure in patients who have complete deltoid ruptures.

PATIENTS AND METHODS

The authors retrospectively analysed ankle fractures in our trauma database from January 2015 to January 2019. 61 patients who sustained ankle fractures with complete deltoid ligament ruptures based on an AP ankle radiographs with increased medial joint space were identified. 25 patients attended clinic for assessment. Of these, 5 were found to have gross planovalgus with pre-existing spring ligament laxity in the uninjured control foot and these were excluded from the analysis. 20 patients were assessed for spring ligament failure /laxity. For each patient, the uninjured foot was used as the control.

RESULTS

The TMT instability score and the lateral translation score showed statistically significant increases in the injured compared to the uninjured foot. The ratio of increase in both TMT instability and lateral translation scores (strain) in the injured versus the uninjured foot was assessed. A strong correlation (+0.62 pearson correlation coefficient) was found between the two ratios.

CONCLUSION

All 20 patients showed increased spring ligament laxity and 19 patients showed increased TMT instability. Our results show that with complete deltoid rupture, there is likely greater disruption of the medial ligamentous structures of the foot than previously recognised. The degree of increase in the spring ligament strain also correlates with the degree of strain at the plantar TMT joint ligaments, and thus first ray instability. This finding has significant implications for the long-term assessment and management of ankle fractures involving complete deltoid disruption. Early intervention with orthotics in this cohort may prevent progressive destabilisation of the midfoot and the first ray. This evolving understanding may lead to the prospect of earlier surgical intervention to reconstitute the integrity of the spring ligament and protect the foot progressing to stage 2 AAFD.

Association between anterior talofibular ligament injury and ankle tendon, ligament, and joint conditions revealed by magnetic resonance imaging

Background

The lateral ankle ligament complex is the most frequently injured ligament secondary to strong ankle inversion movement during lateral ankle sprains (LAS). Among these injuries, anterior talofibular ligament (ATFL) injury is the most frequent condition (present in 66-85% of such injuries). The purpose of this research was to use magnetic resonance imaging (MRI) to determine the association between ankle tendon, ligament, and joint conditions and ATFL injuries.

Methods

A case-control MRI study was carried out to compare the presence of ankle muscle, tendon, ligament, and joint conditions in patients with injured ATFLs (case group; n=25) and non-injured ATFLs (control group; n=25).

Results

Achilles tendinopathy was present in 1/25 (4%) patients with injured ATFLs and 7/25 (28%) non-injured ATFL subjects (P=0.048). Injured calcaneofibular ligaments (CFLs) were present in 19/25 (76%) patients with injured ATFLs and 1/25 (4%) non-injured ATFL subjects (P<0.001). Finally, injured tibiotalar joints were present in 16/25 (64%) patients with injured ATFLs and 5/25 (20%) non-injured ATFL subjects (P=0.002). Other musculoskeletal structure injuries occurred at similar rates between patients with injured ATFLs and those with non-injured ATLFs (P≥0.05).

Conclusions

Patients with ATFL injuries showed a greater presence of CFL and tibiotalar joint injuries than subjects with non-injured ATFLs.

Painful Accessory Navicular and Spring Ligament Injuries in Athletes

Painful accessory navicular and spring ligament injuries in athletes are different entities from more common posterior tibialis tendon problems seen in older individuals. These injuries typically affect running and jumping athletes, causing medial arch pain and in severe cases a pes planus deformity. Diagnosis requires a detailed physical examination, standing radiographs, and MRI. Initial treatment focuses on rest, immobilization, and restriction from sports. Orthotic insoles may alleviate minor pain, but many patients need surgery to expedite recovery and return to sports. The authors review their approach to these injuries and provide surgical tips along with expected rehabilitation to provide optimal outcomes.

Functional assessment of the spring ligament using ultrasonography in the Japanese population

OBJECTIVES

Spring ligament (SL) insufficiency is observed commonly in association with adult-acquired flatfoot deformity. Evaluation of the SL using ultrasonography (US) has not been fully investigated, and the functional characteristics of the spring ligament have not been clarified. The purpose of this study was to perform a functional evaluation of the SL using US.

METHODS

Fifty-one healthy young volunteers (31 males, 20 females; 102 feet) participated in this study. The thickness of the SL in both non-weight bearing (NSL) and 90% weight bearing (WSL) conditions was measured using US. The correlation between assessment of foot alignment (Navicular Drop test (NDT), Arch height Index (AHI), and Arch height flexibility (AHF)) and the thickness of the SL was investigated.

RESULTS

The thickness of the SL in NSL and WSL conditions was 2.28 ± 0.38 mm and 2.13 ± 0.34 mm, respectively. The thickness was 2.42 ± 0.38 mm (NSL)/2.26 ± 0.31 mm (WSL) in males, and 2.07 ± 0.28 mm (NSL)/1.93 ± 0.29 mm (WSL) in females. The standard values of the thickness of the SL were 2.0-2.8 mm in males and 1.8-2.4 mm in females. The thickness of the SL was significantly different between males and females (p < 0.01), but was within the margin of error between NSL and WSL. The relationship between NSL and foot alignment only showed a weak correlation with AHI (r = 0.23, p < 0.05).

CONCLUSIONS

Our results indicate that the SL is a hardy structure that shows little change in thickness on weight bearing in vivo.

Comparative Study of Spring Ligament Reconstructions Using Either Hamstring Allograft or Synthetic Ligament Augmentation

BACKGROUND

Idiopathic flatfeet are usually caused by attenuation of the medial soft tissues rather than a lateral osseous deficiency. Debate continues on whether spring ligament attenuation or posterior tibial tendon (PTT) dysfunction is the initial driver for the deformity. Our comparative prospective study aimed to quantify the radiological and clinical outcomes of 2 techniques for spring ligament reconstruction using a hamstring graft or a synthetic ligament.

METHODS

Seventeen spring ligament reconstructions (SLRs) were performed in 17 patients using synthetic ligament augmentation and 16 SLRs were performed using hamstring allograft in 13 patients. Additional procedures such as gastrocnemius recession, PTT advancement, flexor digitorum longus transfer, and calcaneal osteotomy were performed as required. A minimum of 12 months of follow-up was available for all cases. Radiographic analysis was performed with standardized parameters.

RESULTS

Following SLR with synthetic ligament augmentation, all radiological parameters significantly improved (P < .05). Hamstring allograft SLR also demonstrated significantly improved radiographic parameters in all but Meary's line at final follow-up. At 12 months, patient outcome scores were significantly better in the synthetic ligament group.

CONCLUSION

Reconstruction of the spring ligament using either hamstring allograft or synthetic ligament augmentation provided significant improvements in radiological alignment; however, superior patient-reported outcomes were found in the synthetic ligament augmentation group.

LEVELS OF EVIDENCE

Level III, retrospective cohort study.

Treatment of Stage 4 Flatfoot

Stage 4 flatfoot represents only a small proportion of flatfoot cases and is likely to become even rarer. The evidence base to guide treatment is limited to case series and expert opinion. Therefore, a pragmatic approach to treatment must be taken. Low-demand individuals may manage well with conservative treatment. Surgical management is complex, likely to require staging, and has a significant complication profile. Patients should be fully informed and understanding of this. First principles of surgery should be followed, including restoring hindfoot and ankle joint alignment, appropriate soft tissue balancing, and optimizing function by limiting arthrodeses and subsequent stiffness.

Morphology of Spring Ligament Fibrocartilage Complex Lesions

BACKGROUND

The spring ligament fibrocartilage complex (SLFC) is an important static foot stabilizer comprising the superomedial ligament (SML) and the inferior ligament, with anatomical variations (third ligament). The aim of this study was to describe the patterns of the lesions found during SLFC surgery, to allow direct comparison between the results with various surgical techniques.

METHODS

Fourteen consecutive patients with SLFC lesions were analyzed during surgical treatment. The mean patient age was 37.3 years, and the mean time from injury was 6.9 months. Intraoperative assessments and anatomical descriptions of the lesions were collected.

RESULTS

Three types of lesion were found. In 13 of 14 cases, only the superomedial ligament was involved: five superomedial ligament distentions and eight superomedial ligament ruptures. In one case, total SLFC (superomedial and inferior ligaments) rupture was observed.

CONCLUSIONS

The first classification of SLFC lesions is presented, which is simple, consistent, and based on anatomical description.

Anatomic study of the medial side of the ankle base on the joint capsule: an alternative description of the deltoid and spring ligament

Background

Adult acquired flatfoot deformity (AAFD) is caused by impaired medial ligamentous structures and posterior tibialis tendon dysfunction (PTTD). Although degeneration and trauma could separately cause AAFD, how these factors interact in the pathomechanism of AAFD is unclear. The joint capsule in the medial ankle is considered an important structure, providing passive stability by limiting joint movement. Previous reports on the joint capsule suggest its involvement in pathological changes of the ankle, but because of the high priority placed on the ligaments, few reports address the ankle joint from the joint capsule standpoint. The current study aimed to anatomically examine the medial ankle joint, focusing on the deltoid and spring ligaments in perspective of the joint capsule.

Methods

We conducted a descriptive anatomical study of 19 embalmed cadavers (mean 82.7 years, range 58 to 99). We included 22 embalmed cadaveric ankles. We detached the joint capsule in 16 ankles from the anterior to posteromedial joint, analyzed the capsular attachments of the ankle and adjacent joints, and measured the widths of the bony attachments. We histologically analyzed the joint capsule using Masson’s trichrome staining in 6 ankles.

Results

The capsule could be separated as a continuous sheet, including 3 different tissues. The anterior capsule was composed of fatty tissue. Between the medial malleolus and talus, the capsule was strongly connected and was composed of fibrous tissue, normally referred to as the deep deltoid ligament. The tibial attachment formed a steric groove, and the talar side of the attachment formed an elliptical depressed area. On the medial part of the subtalar and talonavicular joints, the capsule covered the joints as cartilaginous tissue, normally referred to as the superomedial ligament of the spring ligament. The outer side of the cartilaginous and fibrous tissue formed the sheath floor of the posterior tibialis tendon. Histological analysis revealed three different tissue types.

Conclusions

The capsules of the ankle, subtalar, and talonavicular joints could be detached as a continuous sheet. The deltoid and the superomedial ligament of the spring ligaments could be interpreted as a part of the continuous capsule, which had different histological features.

Level of evidence

Descriptive Laboratory Study.

Adult-Acquired Flatfoot Deformity

Adult-acquired flatfoot deformity (AAFD) comprises a wide spectrum of ligament and tendon failure that may result in significant deformity and disability. It is often associated with posterior tibial tendon deficiency (PTTD), which has been linked to multiple demographic factors, medical comorbidities, and genetic processes. AAFD is classified using stages I through IV. Nonoperative treatment modalities should always be attempted first and often provide resolution in stages I and II. Stage II, consisting of a wide range of flexible deformities, is typically treated operatively with a combination of soft tissue procedures and osteotomies. Stage III, which is characterized by a rigid flatfoot, typically warrants triple arthrodesis. Stage IV, where the flatfoot deformity involves the ankle joint, is treated with ankle arthrodesis or ankle arthroplasty with or without deltoid ligament reconstruction along with procedures to restore alignment of the foot. There is limited evidence as to the optimal procedure; thus, the surgical indications and techniques continue to be researched.

Imaging in Foot and Ankle Instability

This article reviews the imaging aspects relevant to ligamentous instabilities of the foot and ankle with a focus on MRI and ultrasound imaging. A pictorial review of the anatomy of the medial and lateral ankle ligaments, syndesmosis, spring ligament, Lisfranc complex, hallux sesamoid complex, and lesser toe plantar plate as seen on MRI is presented. Selected cases of ligamentous pathology relevant to foot and ankle instability are presented. The value of imaging in the assessment of foot and ankle instability is reviewed.

Spring Ligament Instability

The crucial role of the spring ligament complex within the pathologic process that leads to flatfoot deformity has evolved recently. There has been improvement in the anatomic knowledge of the spring ligament and understanding of its complex relationship to the deltoid complex and outstanding advances in biomechanics concepts related to the spring ligament. Optimization of flatfoot treatment strategies are focused on a renewed interest in the spring ligament and medial soft tissue reconstruction in concert with bony correction to obtain an adequate reduction of the talonavicular deformity and restoration of the medial longitudinal arch.

Combined Spring and Deltoid Ligament Repair in Adult-Acquired Flatfoot

BACKGROUND

Adult-acquired flatfoot deformity (AAFD) is usually due to a combination of mechanical failure of the osteoligamentous complex that maintains the medial longitudinal arch of the foot and attenuation or complete tear of the posterior tibial tendon. Magnetic resonance imaging studies in patients with flatfoot deformities have reported the posterior tibial tendon to be pathologic in up to 100% of patients, the spring ligament in up to 87%, and the deltoid ligament in 33%. Many studies in the literature describe reconstruction of the spring ligament or the deltoid ligament associated with AAFD, but there is no study in which both (spring and deltoid) ligaments are reconstructed at the same time. We describe a novel technique to reconstruct the deltoid ligament and the spring ligament at the same time.

METHODS

We described the technique and evaluated 10 consecutive patients with AAFD and insufficient ankle and midfoot ligaments.

RESULTS

We found no postoperative complications, stiffness, or loss of correction.

CONCLUSION

We present a novel technique to reconstruct the failed deltoid and spring ligament during flatfoot correction. It is unique in that it uses internal brace augmentation with FiberTape^® to help and protect the soft tissue healing.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Arthroscopic approach to the spring (calcaneonavicular) ligament

BACKGROUND

This research studied the safety and efficacy of a new portal to the spring ligament. This portal is located just plantar to the insertion of the posterior tibial tendon and above the fibrous septum between the posterior tibial and the flexor digitorum longus tendons.

METHODS

Twelve fresh frozen foot and ankle specimens were used. The distance between the accessory medial portal and the medial plantar nerve was measured. The relation between the medial plantar nerve and the spring ligament was studied. The depth that can be reached through the portal was also assessed.

RESULTS

The average distance between the insertion point of the 3mm diameter metal rod and the medial plantar nerve was 20(6-27)mm. The medial plantar nerve located at lateral third of the ligament in 8 specimens (67%), middle third in 2 specimens (17%) and medial third in 2 specimens (17%). The tip of rod can reach Zone A in all specimens.

CONCLUSION

This study demonstrated that arthroscopic approach and repair of the spring ligament can injure the medial plantar nerve.

CLINICAL RELEVANCE

The clinical relevance of this cadaver study is that it confirmed the feasibility of arthroscopic approach to the whole span of the spring ligament and alerted the potential risk of injury to the medial plantar nerve during arthroscopic assisted repair of the ligament.

Imaging of the Tibionavicular Ligament, and Its Potential Role in Adult Acquired Flatfoot Deformity

BACKGROUND

The spring ligament is an important medial arch stabilizer. However, when disrupted, it does not cause planovalgus deformity until the foot is cyclically loaded. We propose that the tibionavicular (TN) ligament plays an important role. However, this ligament is not imaged in routine magnetic resonance imaging (MRI) sequences.

METHODS

A prospective case-control study using a novel MRI sequence to image the TN ligament in 20 normal feet creating a baseline appearance of the ligament. We then scanned 20 patients with adult acquired flatfoot deformity (AAFD). All patients had weightbearing anteroposterior and lateral radiographs. We followed up patients, the end point being surgery or 18 months' follow-up.

RESULTS

The normal ligament was reliably identified on the novel sequences. It had a reproducible appearance in 2 views, and consistent length and width. Two groups of patients were identified in the AAFD cohort: Normal TN (11/20) (The mean Meary angle was 6.8 degrees) and Abnormal TN (9/20). The ligament was thickened proximally, with distal attenuation and intrasubstance edema. On sagittal sequence, it had dorsal bulging and high signal. The mean Meary angle was 13.2 degrees ( P = .013). All patients had posterior tibial tendon dysfunction and 8 had spring ligament complex attenuation. Five patients have undergone corrective surgery compared to none in the other group.

CONCLUSION

This study adds to the evidence that AAFD is multifactorial. With this imaging technique, we were able to reliably image the TN ligament. We hope that including this sequence into routine scanning will help us understand its role in flatfoot deformity. This poses the question of whether this structure will play a role in reconstructive surgery in future.

LEVEL OF EVIDENCE

Level II, prospective comparative study.

Role of Tendoscopy in Treating Stage II Posterior Tibial Tendon Dysfunction

BACKGROUND

Stage II tibialis posterior tendon dysfunction (PTTD) resistant to conservative therapies is usually treated with invasive surgery. Posterior tibial tendoscopy is a novel technique being used in the assessment and treatment of posterior tibial pathology. The aims of this study were (1) to clarify the role of posterior tibial tendon tendoscopy in treating stage II PTTD, (2) to arthroscopically classify spring ligament lesions, and (3) to compare the arthroscopic assessment of spring ligament lesions with magnetic resonance imaging (MRI) and ultrasonographic (US) data.

METHODS

We reviewed prospectively collected data on 16 patients affected by stage II PTTD and treated by tendoscopy. We report the reoperation rate and functional outcomes evaluated by comparing pre- and postoperative visual analogic scale for pain (VAS-pain) and the Short-Form Health Survey (SF-36; with its physical [PCS] and mental [MCS] components). Postoperative satisfaction was assessed using a VAS-satisfaction scale. One patient was lost to follow-up. Spring ligament lesions were arthroscopically classified in 3 stages. Discrepancies between preoperative imaging and intraoperative findings were evaluated.

RESULTS

At a mean of 25.6 months' follow-up, VAS-pain ( P < .001), SF-36 PCS ( P = .039), and SF-36 MCS ( P < .001) significantly improved. The mean VAS-satisfaction score was 75.3/100. Patients were relieved from symptoms in 80% of cases, while 3 patients required further surgery. MRI and US were in agreement with intraoperative data in 92% and 67%, respectively, for the tendon assessment and in 78% and 42%, respectively, for the spring ligament.

CONCLUSIONS

Tendoscopy may be considered a valid therapeutic tool in the treatment of stage II PTTD resistant to conservative treatment. It provided objective and subjective encouraging results that could allow continued conservative therapy while avoiding more invasive surgery in most cases. MRI and US were proven more useful in detecting PT lesions than spring ligament tears. Further studies on PT could use this tendoscopic classification to standardize its description.

LEVEL OF EVIDENCE

Level IV, therapeutic study, case series.

Long-term follow-up of patients undergoing tibialis posterior transfer: Is acquired pes planus a complication?

In this retrospective study, a series of 10 elective patients treated with transfer of the tibialis posterior (TP) tendon for pes cavus and drop foot are described. Since TP transfer completely subtracts the role of this tendon, this cohort of patients provides an opportunity to examine the consequences of tibialis posterior (TP) deficiency. After a mean follow up period of 44.7 months, only one patient showed evidence of strain in the spring ligament but none of the patients in this series developed clinical or radiological evidence of planovalgus deformity. The authors conclude that planovalgus deformity is not an inevitable sequelae of TP Tendon transfer and that established theory underestimates the role of static soft tissue restraints such as spring ligament in hindfoot stability.

The resistance to failure of spring ligament reconstruction

INTRODUCTION

The spring ligament (SL) is increasingly recognised as the major structure that fails in acquired adult flatfoot deformity (AAFD). This is the first study that demonstrates integrity of repair of the SL.

PATIENTS AND METHODS

Six pairs of fresh frozen cadavers were setup in a standardised fashion with ankle in plantargrade (mean age 59 years, BMI 25). A 25N lateral force was applied to the medial metatarsal head using an algometer. Lateral displacement of the foot was measured with SL intact, sectioned, following FibreWire^® repair, then Arthrex InternalBrace (IB) reconstruction, then with selective sectioning of each limb of the IB reconstruction.

RESULTS

In 12 specimens, overall lateral translation with SL intact was 21mm±4.9. This increased to 39.2mm±10.9 (p<0.05) with SL sectioning, no significant improvement to 34.2mm±9.5 with repair (p=0.159), before significantly returning to baseline 16.55mm±5.1 (p<0.001) with the IB. Augmenting with FDL did not influence lateral translation (p=0.586).

CONCLUSION

Restoration of SL integrity is fundamental to prevent flatfoot. This study shows traditional repair models fail to provide sufficient resistance to planovalgus. Using an augmented device such as the IB provides optimal resistance to lateral translation and hence planovalgus, particularly the plantar limb of the augmentation.

What to Do with the Spring Ligament

The spring ligament complex is an important static restraint of the medial longitudinal arch of the foot and its failure has been associated with progressive flatfoot deformity. Reconstruction of the spring ligament complex is most appropriate in stage II posterior tibial tendon dysfunction, before severe peritalar subluxation and rigid deformity develops. Although an understanding of the spring ligament complex and its contribution to medial arch stability has grown, there is no unanimously accepted surgical technique that has consistently demonstrated satisfactory outcomes. This article reviews the pathoanatomy of the spring ligament complex and the role of spring ligament reconstruction in acquired flatfoot deformity, and highlights current research.

MR Imaging of the Midfoot Including Chopart and Lisfranc Joint Complexes

Following a brief description of the normal anatomy and biomechanics of the midfoot, this article focuses on MR imaging features of common osseous, tendon, and ligament abnormalities that affect the midfoot. Discussion of the anatomy and pathology affecting the Chopart and Lisfranc joint complexes, both of which play important roles in linking the midfoot to the hindfoot and the forefoot respectively, is also included.

Ultrasound evaluation of adult-acquired flatfoot deformity: Emphasis on the involvement of spring ligament

Adult-acquired flatfoot deformity (AAFD), a condition commonly caused by tibialis posterior tendon (TPT) dysfunction, has recently been recognised to encompass a spectrum of other deformities, including the disruption of the spring ligament complex. This case series reviews eight examples of chronic AAFD, outlines the sonographic assessment of the TPT and spring ligament and depicts various abnormalities of the TPT and spring ligament that are relevant to AAFD. The importance to always include the spring ligament during the assessment of AAFD will be addressed, as misdiagnosis of the involvement of the spring ligament could lead to inappropriate operative management.

Novel reconstruction technique for an isolated plantar calcaneonavicular (SPRING) ligament tear: A 5 case series report

BACKGROUND

It is usually accepted that acquired flatfoot deformity after injury is usually due to partial or complete tear of the posterior tibial tendon (PTT), with secondary failure of the other structures which maintain the medial longitudinal arch, such as the plantar calcaneo-navicular (SPRING) ligament. It is unusual to find an isolated Spring Ligament (SL) tear, with an intact TP tendon.

METHODS

The medial arch reconstruction technique of an isolated SL tear in 5 patients is presented discussed in this paper. In these 5 cases the clinical presentation mimicked PTT dysfunction. The operative regimen consisted of three steps: direct repair of the ligament, primary reconstruction of the SL by using FiberWire^® (Arthrex, Inc) and a medial calcaneal osteotomy.

RESULTS

American Orthopedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Score improved from 55.8 (range, 34-74) before surgery to 97.6 (range, 91-100) at more than one year follow-up. No recurrence of the flatfoot deformity was observed at 10 years follow-up.

CONCLUSION

SL tear should be suspected in cases of clinical presentation of medial arc collapse even when PTT is intact. In such cases of isolated SL tear reconstruction of the torn ligament using the method described is recommended.

Arthroscopic Repair of Superomedial Spring Ligament by Talonavicular Arthroscopy

A spring ligament tear can occur because of failure of the tibialis posterior tendon in adult-acquired flatfoot deformity or as an isolated injury with a normal tibialis posterior tendon. The superomedial spring ligament is the most common site of rupture. Compromise of this ligament is a primary causative factor of peritalar subluxation, and a functioning tibialis posterior tendon cannot prevent or correct a planovalgus foot deformity. Therefore, the spring ligament should be repaired in addition to treatment of tibialis posterior tendon abnormalities. The purpose of this technical note is to describe a minimally invasive approach for repair of the superomedial spring ligament by talonavicular arthroscopy.

Talonavicular ligament: prevalence of injury in ankle sprains, histological analysis and hypothesis of its biomechanical function

OBJECTIVE

To assess the prevalence of injury of the talonavicular ligament (TNL) in ankle sprains, its anatomy and the stability of the talonavicular joint (TNJ) before and after dividing the TNL in a cadaver.

METHODS

During a prospective study of 100 patients to assess the outcome of ankle injuries, we noted high incidence of TNL injuries; we will discuss here the TNL findings. Each patient had undergone ultrasound and cone beam CT examination of the ankle. Six TNLs were dissected off fresh-frozen cadaveric feet for histological analysis. In further six cadaveric feet, the stability of the TNJ was assessed by mechanical stress before and after division of the TNL; movement at the joint was assessed by measuring the distance between the talus and navicular bone [talonavicular distance (TD)] using ultrasound. The TD was measured on ten randomly selected ultrasound images by three independent observers and repeated twice by a single observer to determine the inter- and intraobserver reliability.

RESULTS

21% of the patients had an injury to the TNL. Histological examination demonstrated a dense connective tissue composed of bundles of collagen in parallel arrangement along the ligament length. The interobserver and intraobserver reliability of the TD showed almost perfect agreement. Displacement at the TNJ after stress with the TNL intact measured 0.18 ± 0.08 cm and 0.29 ± 0.07 cm (p < 0.005) when divided.

CONCLUSION

The TNL is surprisingly commonly injured in ankle sprains. Its anatomy and histology suggest a role in tensile force transmission during the windlass mechanism in gait. Advances in knowledge: Injury to the TNL is common and has not been described. Its anatomy suggests resistance to tensile forces and its injury allows excessive movement at the TNJ.

Spring ligament complex: Illustrated normal anatomy and spectrum of pathologies on 3T MR imaging

The spring (plantar calcaneonavicular) ligament complex connects the calcaneus and navicular bone of the foot and serves as the primary static stabilizer of the medial longitudinal arch of the foot. In this article, we describe the normal anatomy of the spring ligament complex, illustrate 3T magnetic resonance imaging appearances in its normal and abnormal states, and discuss the pathological associations with relevant case examples.

Endoscopic Repair of the Superficial Deltoid Ligament and Spring Ligament

The plantar calcaneonavicular ligament, also known as the spring ligament, is an important static stabilizer of the medial longitudinal foot arch. Compromise of this ligament is a primary causative factor of peritalar subluxation, and it should be repaired in addition to treatment of tibialis posterior tendon abnormalities. Open repair of the ligament requires extensive soft-tissue dissection. The development of the high distal portal for posterior tibial tendoscopy allows repair of the ligament endoscopically. This, together with endoscopically assisted reconstruction of the tibialis posterior tendon, allows complete endoscopic treatment of stage 2 posterior tibial tendon deficiency. The major structure at risk is the medial plantar nerve. This technique is technically demanding and should be reserved for experienced foot and ankle arthroscopists.

Anatomic Reconstruction Technique for a Plantar Calcaneonavicular (Spring) Ligament Tear

Acquired flatfoot deformity in adults is usually due to partial or complete tearing of the posterior tibial tendon, with secondary failure of other structures such as the plantar calcaneonavicular (spring) ligament (SL), which maintain the medial longitudinal arch. In flexible cases, the tibialis posterior can be replaced with the flexor digitorum longus. It is common practice to suture the SL directly in the case of a tear; however, if the tear is complete, suturing directly to the ligament alone will not be possible. Reconstruction of the ligament is needed; however, no validated methods are available to reconstruct this ligament. The operative technique of SL reconstruction described in this report as a part of acquired flatfoot deformity reconstruction consists of augmenting remnants of the spring from the navicularis to the sustentaculum tali and suspending it to the medial malleolus using 2-mm-wide, long-chain polyethylene suture tape. This technique results in the firm anatomic reconstruction of the SL, in addition to "classic" medial arch reconstruction. We recommend SL reconstruction for medial arch reconstruction when the SL is torn.

Evaluation of standing stability in individuals with flatfeet

OBJECTIVE

Flatfoot is one of the most common foot disorders, which not only influences the performance of the foot but also affects the alignments of the ankle, knee, and hip joints. The performance of the flat-arched individuals differs from that of normal individuals during walking. However, there is not enough information in the literature regarding their standing stability. Moreover, the influence of use of foot insole on standing stability has not been evaluated. Therefore, the aim of this study was to evaluate standing stability in individuals with flatfoot with and without insole.

METHODS

Two groups of normal and flat-arched individuals were recruited into this study. A Kistler force plate was used to measure the center of pressure (CoP), which is recognized as a good approximation of sway of center of gravity in a horizontal plane. Stability was determined by calculating the CoP excursions, path length, and velocity in the mediolateral and anteroposterior directions. The difference between stability in normal individuals and those with flatfoot was examined using the independent t test. The paired t test was used to determine the difference between stability in each group with and without insole. Significant P value was set at α ≤.05.

RESULTS

There was a significant difference between stability of flat-arched and normal individuals based on CoP velocity and total velocity. In addition, there was no direct correlation between the severity of flatfoot and instability during quiet standing. However, the mean values of CoP total velocity during standing with and without insole were significantly different (P < .001).

CONCLUSION

This study suggests that individuals with flatfoot are more unstable when compared with normal individuals during quiet standing. It seems that the foot insole improves the alignment of foot structure and reduces the forces applied on the ligament, thus, improving standing stability. Therefore, stability assessment in patients with flatfoot may be important, and the insole is a useful modality that can be used to improve stability in this patient group.

LEVELS OF EVIDENCE

Therapeutic, Level II: Prospective, comparative trial.

Adult flatfoot

Adult flatfoot is defined as a flattening of the medial arch of the foot in weight-bearing and lack of a propulsive gait. The 3 lesion levels are the talonavicular, tibiotarsal and midfoot joints. The subtalar joint is damaged by the consequent rotational defects. Clinical examination determines deformity and reducibility, and assesses any posterior tibialis muscle deficit, the posterior tibialis tendon and spring ligament being frequently subject to degenerative lesions. Radiographic examination in 3 incidences in weight-bearing is essential, to determine the principal level of deformity. Tendon (posterior tibialis tendon) and ligamentous lesions (spring ligament and interosseous ligament) are analyzed on MRI or ultrasound. In fixed deformities, CT explores for arthritic evolution or specific etiologies. 3D CT reconstruction can analyze bone and joint morphology and contribute to the planning of any osteotomy. Medical management associates insoles and physiotherapy. Acute painful flatfoot requires strict cast immobilization. Surgical treatment associates numerous combinations of procedures, currently under assessment for supple flatfoot: for the hindfoot: medial slide calcaneal osteotomy, calcaneal lengthening osteotomy, or arthroereisis; for the midfoot: arthrodesis on one or several rays, or first cuneiform or first metatarsal osteotomy; for the ankle: medial collateral ligament repair with tendon transfer. Fixed deformities require arthrodesis of one or several joint-lines in the hindfoot; for the ankle, total replacement after realignment of the foot, or tibiotalocalcaneal fusion or ankle and hindfoot fusion; and, for the midfoot, cuneonavicular or cuneometatarsal fusion. Tendinous procedures are often associated. Specific etiologies may need individualized procedures. In conclusion, adult flatfoot tends to be diagnosed and managed too late, with consequent impact on the ankle, the management of which is complex and poorly codified.

Could failure of the spring ligament complex be the driving force behind the development of the adult flatfoot deformity?

We conducted an investigation into the relative associations of magnetic resonance imaging (MRI)-defined pathologic features of the spring ligament and/or tibialis posterior tendon with radiographic evidence of a planovalgus foot position. A total of 161 patient images (MRI and plain radiographs) obtained from the foot and ankle clinic (2008 to 2011) were retrospectively reviewed. All 161 patients (64 male and 97 female; mean age 45.9 years, range 18 to 86) were included in the analysis. Lateral weightbearing radiographs were analyzed for the talo-first metatarsal angle ≥ 5°, calcaneal pitch ≤ 20°, and talocalcaneal angle ≥ 45°. A positive finding for ≥ 1 measurements identified a radiographic planovalgus position of the foot. The radiographic deformity was analyzed against the MRI evidence of either spring ligament or tibialis posterior tendon pathologic features for significance (p < .05). Evidence of a spring ligament abnormality was strongly associated with a planovalgus foot position, reaching high levels of statistical significance in all 3 categories of radiographic deformity (odds ratio 9.2, p < .0001). Abnormalities of the tibialis posterior tendon failed to demonstrate significance, unless grade I changes were excluded, and grade II and III appearances were analyzed in isolation (odds ratio 2.9, p = .04). Although absolute causal relationships were not tested, this investigation has clearly demonstrated that MRI-defined abnormalities of the spring ligament complex are possibly of at least equal importance to tibialis posterior dysfunction for the presence of a moderate to severe radiographic planovalgus foot position.