Biomechanics of procedures used in adult flatfoot deformity

A comprehensive exercise program improves foot alignment in people with flexible flat foot: a randomised trial

QUESTION

In people with flexible flat foot, what is the effect of a comprehensive exercise program on navicular drop height and medial longitudinal arch angle compared with a control regimen of brief active range of motion exercises?

DESIGN

Randomised controlled trial with concealed allocation, blinding of assessors and intention-to-treat analysis.

PARTICIPANTS

Fifty-two people with flexible flat foot.

INTERVENTION

The experimental group undertook 30-minute exercise sessions three times per week for 6 weeks. The exercises involved active dorsiflexion and plantarflexion, foot shortening exercises, gluteal muscle strengthening, and stretching. The control group performed active dorsiflexion and plantarflexion only for 6 weeks.

OUTCOME MEASURES

Navicular drop height and longitudinal arch angle.

RESULTS

Randomisation allocated 26 participants to each group. One participant from the experimental group and two from the control group did not complete the study. After 6 weeks, the participants in the experimental group improved their navicular drop height by 0.4 cm (95% CI 0.4 to 0.5) more than those in the control group. These participants also improved their longitudinal arch angle by 16 deg (95% CI 13 to 19) more than those in the control group.

CONCLUSION

In people with flexible flat foot, a comprehensive 6-week exercise program improved the navicular drop height and longitudinal arch angle more than active dorsiflexion and plantarflexion alone. This improved the cosmetic appearance of the foot and reduced progression towards more severe flat foot, which typically becomes symptomatic.

TRIAL REGISTRATION

CTRI/2021/07/034599.

Pie plano y tratamientos conservadores en adultos físicamente activos. Una revisión sistemática

El término pie plano es utilizado para describir cualquier anormalidad que causa el colapso del arco longitudinal medial del pie, cuando es sintomático condiciona el grado, tipo y calidad de actividad física que practique un adulto. Como objetivo nos planteamos revisar los tratamientos conservadores existentes para el pie plano en adultos jóvenes y de mediana edad. Siguiendo las directrices de la declaración PRISMA, se realizó una revisión sistemática de la literatura científica publicada sobre el pie plano y tratamientos conservadores. Los tratamientos conservadores para el pie plano son aplicados de manera aislada o en combinación, estos incluyen ejercicios de fortalecimiento, de estiramientos, uso de ortesis, aplicación de vendaje, modificación del calzado y estimulación eléctrica. Son requeridos estudios de tratamientos conservadores en adultos de mediana edad con pie plano sintomático que evalúen el efecto a corto y largo plazo de los actuales protocolos en poblaciones con diferente nivel de condición física. 

The role of medial ligaments and tibialis posterior in stabilising the medial longitudinal foot arch: a cadaveric gait simulator study

BACKGROUND

Debate exists whether adult acquired flatfoot deformity develops secondary to tibialis posterior (TibPost) tendon insufficiency, failure of the ligamentous structures, or a combination of both.

AIM

The aim of this study is to determine the contribution of the different medial ligaments in the development of acquired flatfoot pathology. Also to standardise cadaveric flatfoot models for biomechanical research and orthopaedic training.

METHODS

Five cadaveric feet were tested on a dynamic gait simulator. Following tests on the intact foot, the medial ligaments - fascia plantaris (FP), the spring ligament complex (SLC) and interosseous talocalcaneal ligament (ITCL) - were sectioned sequentially. Joint kinematics were analysed for each condition, with and without force applied to TibPost.

RESULTS

Eliminating TibPost resulted in higher internal rotation of the calcaneus following the sectioning of FP and SLC (d>1.28, p = 0.08), while sectioning ITCL resulted in higher external rotation without TibPost (d = 1.24, p = 0.07). Sequential ligament sectioning induced increased flattening of Meary's angle.

CONCLUSION

Function of TibPost and medial ligaments is not mutually distinctive. The role of ITCL should not be neglected in flatfoot pathology; it is vital to section this ligament to develop flatfoot in cadaveric models.

Decision Tree-Based Foot Orthosis Prescription for Patients with Pes Planus

Pes planus, one of the most common foot deformities, includes the loss of the medial arch, misalignment of the rearfoot, and abduction of the forefoot, which negatively affects posture and gait. Foot orthosis, which is effective in normalizing the arch and providing stability during walking, is prescribed for the purpose of treatment and correction. Currently, machine learning technology for classifying and diagnosing foot types is being developed, but it has not yet been applied to the prescription of foot orthosis for the treatment and management of pes planus. Thus, the aim of this study is to propose a model that can prescribe a customized foot orthosis to patients with pes planus by learning from and analyzing various clinical data based on a decision tree algorithm called classification and regressing tree (CART). A total of 8 parameters were selected based on the feature importance, and 15 rules for the prescription of foot orthosis were generated. The proposed model based on the CART algorithm achieved an accuracy of 80.16%. This result suggests that the CART model developed in this study can provide adequate help to clinicians in prescribing foot orthosis easily and accurately for patients with pes planus. In the future, we plan to acquire more clinical data and develop a model that can prescribe more accurate and stable foot orthosis using various machine learning technologies.

Biomechanics of Medial Ankle and Peritalar Instability

The deltoid and spring ligaments are the primary restraints against pronation and valgus deformity of the foot, and in preserving the medial arch. The posterior tibial tendon has a secondary role in plantar arch maintenance, and its biomechanical stress increases considerably when other tissues fail. A thorough understanding of the anatomy and biomechanics of the deltoid-spring ligament is crucial for successful reconstruction of the tibiocalcanealnavicular ligament, hence, to restore ankle and medial peritalar stability. Although effective in correcting the deformity, tibionavicular tenodesis might be critical, as it blocks physiologic pronation of the hindfoot, which may result in dysfunction and pain.

The effects of individually designed insoles on pes planus treatment

The aim of this study was to examine the effects of individually designed insole in pes planus treatment. Designed insoles was adjusted according to height, length and function of the sole of each participant with pes planus in order to improve the physical parameters of them. A total of 34 participants (17 males and 17 females) with pes planus participated in the study. Height, weight, percent body fat, 30-m sprint test, vertical jump, 12-min Cooper test and Visual Analog Scale (VAS) measurement were obtained before the study and after 1 year later. Wilcoxon signed rank test was conducted to examine whether there were any differences between the pre- and post-test measurements. It was determined that individually designed insoles reduced body weight and BMI, made positive improvements in 30-m speed, vertical jump and 12-min Cooper scores, and significant decrease in VAS scores. In conclusion, it is seen that individually designed insoles have beneficial role in normalizing forces acting on the foot and improve the physical performance parameters of individuals with pes planus. Future studies are needed to explore the long-term effects of individually designed insoles and prefabricated insoles.

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.

Biomechanics and Orthotic Treatment of the Adult Acquired Flatfoot

The adult acquired flatfoot deformity resulting from posterior tibial tendon dysfunction is the result of rupture of the posterior tibial tendon as well as key ligaments of the ankle and hindfoot. Kinematic studies have verified certain levels of deformity causing hindfoot eversion, lowering of the medial longitudinal arch and forefoot abduction. The condition is progressive and left untreated will cause significant disability. Bracing with ankle-foot orthoses has shown promising results in arresting progression of deformity and avoiding debilitating surgery. Various types of ankle-foot orthoses have been studied in terms of effects on gait as well as efficacy in treatment.

Severe Flexible Pes Planovalgus Deformity Correction Using Trabecular Metallic Wedges

BACKGROUND:

Lateral column lengthening and plantarflexion dorsal opening wedge osteotomy of the medial cuneiform are 2 commonly used procedures to address the deformity seen in severe flexible pes planovalgus deformity. Traditionally, iliac crest allograft or autograft has been used to fill the osteotomy sites. Porous metallic wedges can be used as an alternative to avoid the concerns associated with both autograft and allograft.

METHODS:

We performed a retrospective review of patients who had corrective osteotomies utilizing metallic wedges to address flexible pes planovalgus with at least 2 years of follow-up data. Preoperative radiographic measurements (anteroposterior [AP] and talo-first metatarsal angle, calcaneal pitch, talocalcaneal angle, and talonavicular uncoverage angle) and functional scores (visual analog scale [VAS] pain, Foot and Ankle Ability Measure [FAAM] Activities of Daily Living [ADL], FAAM Sports) were compared to postoperative radiographic measurements and functional scores.

RESULTS:

There were statistically significant improvements in all radiographic parameters and functional scores. Two nonunions were seen, one of which healed with revision surgery while the other was asymptomatic. At the time of last radiographic follow-up, there were no recurrences of deformity or collapse.

CONCLUSION:

Porous metallic wedges offer an attractive alternative to autograft and/or allograft in the setting of corrective osteotomies for severe flexible pes planovalgus. Patients who underwent corrective osteotomies using these wedges demonstrated reliable, effective, and stable radiographic correction as well as significant improvements in function and pain.

LEVEL OF EVIDENCE:

Level IV, case series.

Flatfoot and normal foot a comparative analysis of the stress shielding

Objective

this study aims to develop a comprehensive 3D FE model of the foot to investigate the effect of soft tissue stiffness on the plantar pressure distributions and the internal load transfer between bony structures.

Methods

the stress shielding occurring on the plantar surface of a flatfoot was investigated and compared with the mechanical behavior of a healthy foot, trough baropodometric analyses and the FE models.

Results

the flatfoot evidences a more intensive stress-shielding map with significant values of pressure acting on the medial plantar fascia.

Conclusion

Clinically and radiographically, symptomatic adult flatfoot is a complex abnormality involving all three dimensions and multiple joints within the foot.

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.

Towards patient-specific medializing calcaneal osteotomy for adult flatfoot: a finite element study

Clinically in medializing calcaneal osteotomy (MCO), foot and ankle surgeons are facing difficulties in choosing appropriate surgical parameters due to the individual differences in deformities among flatfoot patients. Traditional cadaveric studies have provided important information regarding the biomechanical effects of tendons, ligaments, and plantar fascia, but limitations have been reached when dealing with individual differences and tailoring patient-specific surgeries. Therefore, this study aimed at implementing the finite element (FE) method to investigate the effect of different MCO parameters to help foot and ankle surgeons performing patient-specific surgeries. This study constructed FE models of a flatfoot and a healthy foot based on computed tomography (CT) images. After validating the FE models with experimental measurements, differences in plantar stress were compared between two models and a criterion was established for evaluating the performance of surgical simulations. Four MCO parameters were then studied through FE simulations. Results suggested that the transverse angle, β, and translation distance, d, affected surgical performance. Therefore, special attentions may be recommended when choosing these two parameters clinically. However, the sagittal angle, α, and osteotomy position, p, were found to have less effect on the MCO performance.

An attachment-based description of the medial collateral and spring ligament complexes

BACKGROUND

Anatomy of the medial collateral and spring ligament complexes has been the cause of confusion. The anatomic description is highly dependent on the source studied and little agreement exists between texts. In addition, inconsistent nomenclature has been used to describe the components. This study attempted to clarify confusion through the creation of a 3D ligament map using attachment-based dissection.

METHODS

Nine fresh foot and ankle specimens were observed. The medial collateral ligament and spring ligament complexes were dissected using their attachment sites as a guide to define individual components. Each component's perimeter and thickness was measured and each bony attachment was mapped using a microscribe 3D digitizer.

RESULTS

Five components were identified contributing to the ligament complexes of interest: the tibiocalcaneonavicular, superficial posterior tibiotalar, deep posterior tibiotalar, deep anterior tibiotalar, and inferoplantar longitudinal ligaments. The largest component by total attachment area was the tibiocalcaneonavicular ligament followed by the deep posterior tibiotalar ligament. The largest ligament surface area of attachment to the tibia and talus was the deep posterior tibiotalar ligament. The largest attachment to the navicular and calcaneus was the tibiocalcaneonavicular ligament, which appeared to function in holding these bones in proximity while supporting the head of the talus.

CONCLUSION

By defining complex components by their attachment sites, a novel, more functional and reproducible description of the medial collateral and spring ligament complexes was created.

CLINICAL RELEVANCE

The linear measurements and 3D maps may prove useful when attempting more anatomically accurate reconstructions.

Surgical decision making for stage IV adult acquired flatfoot disorder

Adult acquired flatfoot deformity is a debilitating musculoskeletal condition affecting the lower extremity. Posterior tibial tendon dysfunction (PTTD) is the primary etiology for the development of a flatfoot deformity in an adult. PTTD is classified into 4 stages (with stage IV subdivided into stage IV-A and IV-B). This classification is described in detail in this article.

Approach and treatment of the adult acquired flatfoot deformity

Adult acquired flatfoot deformity (AAFD), embraces a wide spectrum of deformities. AAFD is a complex pathology consisting both of posterior tibial tendon insufficiency and failure of the capsular and ligamentous structures of the foot. Each patient presents with characteristic deformities across the involved joints, requiring individualized treatment. Early stages may respond well to aggressive conservative management, yet more severe AAFD necessitates prompt surgical therapy to halt the progression of the disease to stages requiring more complex procedures. We present the most current diagnostic and therapeutic approaches to AAFD, based on the most pertinent literature and our own experience and investigations.

Management of the rigid arthritic flatfoot in the adults: alternatives to triple arthrodesis

Every alternative to triple arthrodesis in the rigid acquired flatfoot deformity is predicated on limiting the patient exposure to the complication associated with triple arthrodesis. When possible, avoiding arthrodesis of either the talonavicular and calcaneocuboid joints, with their higher nonunion rates, seems a cogent option. Successful treatment is dependent on thoughtful patient evaluation and examination, meticulous joint preparation, careful positioning with rigid fixation, and judicious use of adjunctive procedures to achieve the goal of a plantigrade foot that functions well and is minimally painful.

Update on stage IV acquired adult flatfoot disorder: when the deltoid ligament becomes dysfunctional

Deltoid ligament complex insufficiency is a fundamental pathologic component of stage IV AAFD. Failure of the deltoid ligament allows the talus to tilt into valgus within the ankle mortise. If left untreated, ankle joint biomechanics are altered and may lead to debilitating tibiotalar arthritis. All surgical treatments that address the valgus talar tilt seen with stage IV AAFD require accompanying procedures to properly realign the hindfoot. Stage IV AAFD can be subdivided into two groups. Patients with a flexible ankle deformity without advanced tibiotalar arthritis (stage IV-A) can be considered for a joint-sparing procedure. A variety of procedures have been described, but longterm follow-up studies have yet to determine which of these techniques is optimal. Patients with a rigid valgus ankle deformity or a flexible deformity accompanied by advanced tibiotalar arthritis (stage IV-B) should be considered for a joint-sacrificing procedure. To date, the most reliable results for stage IV-B AAFD have been reported with either tibiotalocalcaneal or pan-talar arthrodesis.

Subtalar and naviculocuneiform fusion for extended breakdown of the medial arch

Combined subtalar and naviculocuneiform fusion was successful in restoring the longitudinal medial arch after extended breakdown while preserving the talon avicular joint. This surgical technique was shown to give a reliable fusion and biomechanically stable position of the foot. In this review article, we summarize the medial column procedures for flatfoot deformity and present our surgical technique and results of 10 consecutive patients treated with this method at a minimum 1-year follow-up.

The modified Kidner-Cobb procedure for symptomatic flexible pes planovalgus and posterior tibial tendon dysfunction stage II: review of 50 feet in 39 patients

Symptomatic flatfoot is a prevalent disorder. We undertook a review of 50 feet in 39 patients with flexible flatfoot treated between August 2000 and January 2008 in order to evaluate the modified Kidner-Cobb procedure. Overall clinical results were rated as good in 48 (96%) feet and fair in 2 (4%) feet, and there were no poor results. Average follow-up was 4.6 years, and total recovery time was 5.7 months in older patients and 3.7 months in children. Manual muscle-strength testing revealed no difference in tibialis anterior strength between the operated and contralateral extremity. All patients visually demonstrated postoperative elevation of the medial longitudinal arch height. Complications included 2 feet with wound dehiscence and 1 foot with fractured hardware. The results of this review indicate that the modified Kidner-Cobb procedure is a useful treatment option for patients with symptomatic flexible flatfoot with posterior tibial tendon dysfunction stage 2.

Conservative treatment of tibialis posterior tendon dysfunction--a review

BACKGROUND

Appropriate conservative treatment is considered essential to address symptoms associated with tibialis posterior tendon dysfunction (TPTD) and prevent its potential long-term disabling consequences. The main aim of this review, undertaken in 2007, was to evaluate the evidence from studies for the effects of conservative treatment modalities in the management of TPTD. This evidence could then be used as a basis for the development of a clinical guideline for the management of the condition.

METHODOLOGY

Studies were selected according to specific criteria and evaluated for methodological quality. As preliminary literature searches had identified no randomised controlled trials at the time of the review, studies of lower hierarchy were included.

RESULTS

Five uncontrolled observational studies evaluating the outcomes of various orthotic treatments alone or in combination with other therapies were included in the review. Different study designs, methodological quality, population characteristics, interventions and outcome measures were found.

DISCUSSION

Limited and poor quality evidence was found in this review regarding the conservative treatment of TPTD. Thus a cause-effect relationship between intervention and outcome could not be established nor an optimal conservative treatment regime for the condition. Further better quality research is warranted in this area to inform practice, particularly as there is no consensus in the literature regarding treatment of this condition.

A review of 51 talonavicular joint arthrodeses for flexible pes valgus deformity

The purpose of this study was to evaluate the radiographic and clinical outcomes of isolated talonavicular arthrodesis in the treatment of the flexible pes valgus foot type. Retrospectively, 51 consecutive isolated talonavicular arthrodeses in 41 patients were evaluated. The mean patient age was 47 (range 9 to 72) years, and the mean follow-up duration was 43.3 (range 11 to 113) months. The mean 10-cm categorical pain score before the surgery was 7.60 +/- 2.37, and this improved to 1.90 +/- 2.38 postoperatively, and this difference was statistically significant (P < .001). We also measured the preoperative and postoperative percent of talar uncovering, calcaneocuboid angle, Kite's angle, talar dome height, calcaneal inclination angle, and Meary's angle, and observed statistically significant (P < .001) improvements in all of these. Fifty-one (100%) of the cases progressed to radiographic osseous union, although 2 (3.92%) of the cases were considered delayed unions. Moreover, 4 (7.84%) of the cases displayed juxta-articular arthrosis postoperatively, and 2 (3.9%) cases developed transfer pain to the lateral column. The authors concluded that isolated talonavicular arthrodesis is a safe and effective procedure for the treatment of painful pes valgus deformity.

Foot pain: biomechanical basics as a guide for assessment and treatment

A large percentage of Americans will likely have a foot problem in their lifetime. Foot pain has a multitude of diagnoses; however, most can be properly diagnosed with a basic understanding of the biomechanics of gait. For pain-free ambulation, human feet go through a series of rotatory motions involving pronation and supination. Pathologic biomechanics are generally divided into excessive pronation or excessive supination. Treatment is often directed at minimizing the pathologic biomechanical forces to assist with pain-free walking.

The effects of sectioning the spring ligament on rearfoot stability and posterior tibial tendon efficiency

Posterior tibial tendon insufficiency has been implicated as a cause of adult acquired flatfoot. Multiple theories are debated as to whether or not a flatfoot deformity develops secondary to insufficiency of the posterior tibial tendon or of the ligamentous structures such as the spring ligament complex. This cadaveric study was undertaken in an attempt to determine the effect that sectioning the spring ligament complex has on foot stability, and whether engagement of the posterior tibial tendon would be able to compensate for the loss of the spring ligament complex. A 3-dimensional kinematic system and a custom-loading frame were used to quantify rotation about the talus, navicular, and calcaneus in 5 cadaveric specimens, before and after sectioning the spring ligament complex, while incremental tension was applied to the posterior tibial tendon. This study demonstrated that sectioning the spring ligament complex created instability in the foot for which the posterior tibial tendon was unable to compensate. Sectioning the spring ligament complex also produced significant changes in talar, navicular, and calcaneal rotations. During simulated midstance, the navicular plantarflexed, adducted, and everted; the talar head plantarflexed, adducted, and inverted; and the calcaneus plantarflexed, abducted, and everted, after sectioning the spring ligament complex. The results of this study indicate that the spring ligament complex is the major stabilizer of the arch during midstance and that the posterior tibial tendon is incapable of fully accommodating for its insufficiency, suggesting that the spring ligament complex should be evaluated and, if indicated, repaired in flatfoot reconstruction.

LEVEL OF CLINICAL EVIDENCE

5.

Calcaneal osteotomies for the treatment of adult-acquired flatfoot

Calcaneal osteotomies are useful procedures for the treatment of stage 2 adult-acquired flatfoot. Often combined with adjunctive soft-tissue procedures, the posterior calcaneal displacement osteotomy and Evans procedure provide effective realignment of pes planovalgus deformity. Preoperative evaluation, indications, contraindications, surgical considerations and techniques are discussed.

The flexible flatfoot in the adult

The adult acquired flatfoot deformity is characterized by flattening of the medial longitudinal arch with insufficiency of the supporting posteromedial soft tissue structures of the ankle and hindfoot. While the etiology of this deformity can be arthritic or traumatic in nature, it is most commonly associated with posterior tibial tendon dysfunction (PTTD). By one estimate, PTTD affects approximately five million people in the United States. The clinical presentation of adult flatfoot can range from a flexible deformity with normal joint integrity to a rigid, arthritic foot.

Advances in orthotics and bracing

Understanding of the adult acquired flatfoot deformity (AAFD) continues to grow, as does the sophistication of orthotics and braces used to treat this disorder. This article reviews these advances and some of the devices commonly used to treat patients who have AAFD. Additionally, the recent proliferation and potential implications of mass-manufactured products is discussed.

Stage IV posterior tibial tendon rupture

Adult acquired flatfoot deformity progresses through well defined stages as set out by Johnson and Strom. Myerson modified this classification system with the addition of a fourth, more advanced stage of the disease. This stage describes the involvement of the tibiotalar joint in addition to the hindfoot malalignment seen in stages II and III. This most advanced stage is comprised of a hindfoot valgus deformity, resulting from degeneration of the posterior tibial tendon, with associated valgus tilting of the talus within the mortise. The deformity at the tibiotalar joint may or may not be rigid. Although rigid deformities are still best treated with fusions of the ankle and hindfoot, supple tibiotalar deformity may be treated with joint sparing procedures involving reconstructive procedures of the foot and deltoid ligaments.

Pediatric and adult flatfoot reconstruction: subtalar arthroereisis versus realignment osteotomy surgical options

One of the most common presenting problems to most foot and ankle surgical practices is the painful flatfoot. Often, the problem is treated with excellent outcomes through a combination of conservative options. In certain cases, conservative care may not alleviate the associated symptoms of foot, ankle, knee, and possibly even back fatigue, pain of the foot and leg, and arthritis of the midfoot, rearfoot, or ankle. In such cases, multiple surgical options are available to treat the underlying deformity and associated symptoms. it is essential to treat the foot and leg as a unit and not to perform surgical based on rapid recovery abut rather on a long-term stable and lasting outcome.

Radiographic assessment of adult flatfoot

BACKGROUND

The accurate measurement of flatfoot on standing radiographs allows correct diagnosis of the condition and evaluation of reconstructive procedures.

METHOD

The standing radiographic measurements of patients with symptomatic, adult flatfoot were compared to controls using blinded observers.

RESULTS

On the lateral radiograph, the talar-to-first metatarsal angle, the calcaneal pitch angle, and the medial cuneiform-fifth metatarsal height differed significantly between the patient group and the controls. The difference in the talar-to-first metatarsal angles on lateral radiographs was the most statistically significant (patient group 21.1 +/- 10.8 degrees and control 7.1 +/- 10.7 degrees, p < 0.0001) with good correlation between readings (intraobserver 0.75, interobserver 0.83). On the anteroposterior (AP) radiograph, the talar head uncoverage distance was the most significantly different measurement between these groups.

CONCLUSIONS

These findings support the hypothesis that the talar-first metatarsal angle is an accurate radiographic identifier of patients with symptomatic, adult flatfoot.

Posterior tibial tendon insufficiency: which ligaments are involved?

BACKGROUND

The pathology manifested in posterior tibial tendon insufficiency (PTTI) is not limited to the posterior tibial tendon. The association of ligament failure with deformity has been discussed in numerous publications, but extensive documentation of the structures involved has not been performed. The purpose of this observational study was to identify the pattern of ligament involvement using standardized, high-resolution magnetic resonance imaging (MRI) in a series of 31 consecutive patients diagnosed with PTTI compared to an age matched control group without PTTI.

METHOD

The structures evaluated by MRI were the posterior tibial tendon, superomedial and inferomedial components of the spring ligament complex, talocalcaneal interosseous ligament, long and short plantar ligaments, plantar fascia, deltoid ligament, plantar naviculocuneiform ligament, and tarsometatarsal ligaments. Structural derangement was graded on a five-part scale (0 to IV) with level 0 being normal and level IV indicating a tear of more than 50% of the cross-sectional area of the ligament. Standard flatfoot measurements taken from preoperative plain standing radiographs were correlated with the MRI grading system.

RESULTS

Statistically significant differences in frequency of pathology in the PTTI group and controls were found for the superomedial calcaneonavicular ligament (p < 0.0001), inferomedial calcaneonavicular ligament (p < 0.0001), interosseous ligament (p = 0.0009), anterior component of the superficial deltoid (p < 0.0001), plantar metatarsal ligaments (p = 0.0002) and plantar naviculocuneiform ligament (p = 0.0006). The ligaments with the most severe involvement were the spring ligament complex (superomedial and inferomedial calcaneonavicular ligaments) and the talocalcaneal interosseous ligament.

CONCLUSION

Ligament involvement is extensive in PTTI, and the spring ligament complex is the most frequently affected. Because ligament pathology in PTTI is nearly as common as posterior tibial tendinopathy, treatment should seek to protect or prevent progressive failure of these ligaments.

Stage IV posterior tibial tendon insufficiency: the tilted ankle

Stage IV PTTD is the most challenging of the posterior tibial tendon deficiencies. The combination of a flattened longitudinal arch and a tilted ankle make successful management unpredictable. Conservative management universally fails and surgical options have been limited to pantalar and tibiotalocalcaneal arthrodesis. Alternatives to surgical management included herein are unproven, but provide a potential solution beyond that of arthrodesis.

Soft tissue procedures

Soft tissue procedures for PTT dysfunction and adult acquired flat foot improve function and preserve joint motion. These procedures can only be applied to patients who have correctable deformities. The durability of these procedures, without the addition of bone realignment procedures, has been questioned and needs to be investigated further. Reconstruction of the spring ligament complex corrects the flat foot in cadavers but has not been studied clinically. There is still much to be learned in this condition so we are able to provide optimal care for our patients.

Lateral-sided bony procedures

Treatment of any hindfoot deformity should include correction of the deformity and preservation of complex hindfoot motion. This important motion is protective of adjacent, and more removed, joints in that it serves a shock-absorbing function and protects them from stresses. Lateral column lengthening combined with a medial soft-tissue procedure is the treatment of choice for stage II flat foot. Patients who have significant subluxation of the subtalar joint will also need a medial displacement calcaneal osteotomy to correct the hindfoot valgus. Only patients who have a rigid foot secondary to degenerative changes will require an arthrodesis to correct the deformity and provide pain relief. Unfortunately, although fusion works well to correct deformity, it accelerates future degenerative changes.

Biomechanics and pathophysiology of flat foot

When the foot works properly it is an amazing, adaptive, powerful aid during walking, running, jumping, and in locomotion up or down hill and over uneven ground. Dysfunction of the foot can often arise from the foot losing its normal structural support, thus altering is shape. An imbalance in the forces that tend to flatten the arch and those that support the arch can lead to loss of the medial longitudinal arch. An increase in the arch-flattening effects of the triceps surae or an increase in the weight of the body will tend to flatten the arch. Weakness of the muscular, ligamentous, or bony arch supporting structures will lead to collapse of the arch. The main factors that contribute to an acquired flat foot deformity are excessive tension in the triceps surae, obesity, PTT dysfunction, or ligamentous laxity in the spring ligament, plantar fascia, or other supporting plantar ligaments. Too little support for the arch or too much arch flattening effect will lead to collapse of the arch. Acquired flat foot most often arises from a combination of too much force flattening the arch in the face of too little support for the arch. Treatment of the adult acquired flat foot is often difficult. The clinician should remember the biomechanics of the normal arch and respond with a treatment that strengthens the supporting structures of the arch or weakens the arch-flattening effects on the arch. After osteotomies or certain hindfoot fusions, the role of the supporting muscles of the arch, in particular the PTT, play less of a role in supporting the arch. Rebalancing the forces that act on the arch can improve function and lessen the chance for further or subsequent development of deformity.