The effect of Stage II posterior tibial tendon dysfunction on deep compartment muscle strength: a new strength test

Influence of ankle invertor muscle fatigue on workload of the lower extremity joints during single-leg landing in the sagittal and frontal planes

BACKGROUND

Insufficient rigidity of the foot owing to its ligaments and muscles can decrease the attenuation of the ground reaction force during landing. Therefore, dysfunction of the ankle invertors may increase the proximal joint load during landing.

RESEARCH QUESTION

What are the effects of the fatigued ankle invertors on workload in the lower extremity joints during single-leg landing?

METHODS

Twenty-seven young adults (13 men and 14 women) performed landing trials in the forward and medial directions before and after exercise-induced fatigue of the ankle invertors. The exercise consisted of repeated concentric and eccentric ankle inversions until the maximum torque was below 80% of the baseline value. Negative joint workload during the landing tasks was calculated for the hip, knee, and ankle in the sagittal and frontal planes. Additionally, lower extremity work (the sum of the work of the hip, knee, and ankle) was calculated.

RESULTS

Invertor fatiguing exercise resulted in a significant increase in negative joint work in the frontal and sagittal plane hip and the frontal plane knee during medial landing, whereas no significant change in negative joint work was observed during forward landing.

SIGNIFICANCE

These findings suggested that ankle invertor dysfunction may induce a high load on the proximal joints and have direction-specific effects.

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

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

A 3-Dimensional Gait Analysis of the Effects of Fatigue-Induced Reduced Foot Adductor Muscle Strength on the Walking of Healthy Subjects

Dysfunction of the tibialis posterior muscle is the most common cause of adult acquired flat foot. Tibialis posterior muscle weakness has been observed in several patient populations, including those in the early stages of rheumatoid arthritis. However, the influence of tibialis posterior weakness on gait mechanics is not fully understood, although gait instability has been reported. In 24 healthy participants, 3-dimension lower limb kinematics and kinetics during walking were evaluated bilaterally, before and after, a muscle fatigue protocol aiming to decrease the right foot adductor muscles strength, including the tibialis posterior muscle. The 3-dimension gait kinematics and kinetics were analyzed with statistical parametric mapping. The stance phase duration was increased for the right side. The right ankle external rotation moment decreased, and the left hip extension moment increased with reduced muscle strength compared with normal strength conditions. These changes are similar in patients with dysfunction in the tibialis posterior muscle, indicating that compensatory strategies observed in these patients might be related to the loss of tibialis posterior muscle strength. Such strategies may involve the unaffected side.

Gait alterations in posterior tibial tendonitis: A systematic review and meta-analysis

BACKGROUND

Posterior tibial tendon dysfunction (PTTD) is a common and debilitating tendinopathy that can lead to a profound decrease in gait function. While the clinical diagnosis and treatment of this disorder are well described, the pathomechanics have not been adequately characterized. The purpose of this systematic review and meta-analysis is to compare foot/ankle kinematics and kinetics in patients with PTTD with healthy controls during gait.

METHODS

Relevant articles were selected thought Medline (Pubmed), Scopus, CINAHL, and Web of Science. Studies focused on foot/ankle kinematics and kinetics in patients with PTTD were involved. Articles were included if they: 1) compared patients with PTTD to healthy controls, 2) utilized kinematics or kinetics as the primary outcome measure, 3) evaluated gait tasks, and 4) were written in English.

RESULTS

Eleven articles were included in this systematic review, and 8 studies were synthesized and analyzed. Our meta-analyses indicated increased dorsiflexion and abduction of the forefoot, as well as increased plantarflexion and eversion of hindfoot for patients with PTTD during stance of walking.

CONCLUSION

Our results from the meta-analysis showed more conclusive changes in the forefoot (increased dorsiflexion and abduction) and hindfoot (increased plantarflexion and eversion) kinematics during stance of walking, which may be associated with a pathological process of PTTD. This review provides an improved understanding of gait function in patients with PTTD and preliminary knowledge for future research.

"I need somebody who knows about feet" a qualitative study investigating the lived experiences of conservative treatment for patients with posterior tibial tendon dysfunction

Background

Posterior tibial tendon dysfunction is a disabling, chronic, progressive tendon condition that detrimentally affects foot, ankle and lower limb function. Research suggests that posterior tibial tendon dysfunction is poorly recognised and difficult to treat. When posterior tibial tendon dysfunction is diagnosed, the clinician is faced with a weak evidence base and guidelines for the common conservative treatments.to guide their management. Moreover, there are no current evidence-based guidelines for the conservative management of posterior tibial tendon dysfunction. Emerging research suggests that posterior tibial tendon dysfunction not only has a physical impact on the patient, but it also has psychosocial impact on quality of life.Conservative treatments for posterior tibial tendon dysfunction are generally undertaken during early management. The most common are foot orthoses, exercises, bracing, lifestyle changes and injections. Quantitative evidence supporting conservative treatments for posterior tibial tendon dysfunction in relation to function, pain and patient reported outcome measures are reported in the literature.There is a paucity of qualitative research investigating the psychosocial impact of the common treatments for posterior tibial tendon dysfunction. Interpretative phenomenology is concerned with lived experience which is involves the detailed exploration of experience which is embedded within the social and temporal contexts of the lifeworld of the person. The aim of study research is to investigate the lived experience of conservative treatments for patients who have posterior tibial tendon dysfunction using Interpretative Phenomenological Analysis.

Methods

Five participants with posterior tibial tendon dysfunction were purposively recruited from a private podiatry practice and semi-structured interviews were conducted to examine their lived experiences of treatment for posterior tibial tendon dysfunction. The data for this study was collected and analysed using Interpretative Phenomenological Analysis.

Results

This research identified three superordinate themes which influenced the lived experience of treatment for these patients (i) adverse experience during the patient journey (ii) treatment burden, and (iii) negative self-concept.

Conclusion

This study highlights some of what is anecdotally known about the lived experience of treatment for patients with posterior tibial tendon dysfunction, but has never been studied in a qualitative, methodological manner. This study addresses the gap in the qualitative literature. It reveals novel aspects of the lived experience throughout the patient journey, the detrimental impact of treatment burden, loss and negative self-concept. This evidence is important because it highlights the need for a greater understanding of the psychological and social factors that can influence the lived experience of treatment for this group of patients.

Self-reported social and activity restrictions accompany local impairments in posterior tibial tendon dysfunction: a systematic review

BACKGROUND

Posterior tibial tendon dysfunction (PTTD) is a painful, progressive tendinopathy that reportedly predominates in middle-age, overweight women. There is no evidence based guidelines that clinicians can use to guide treatment planning, which leaves clinicians to make decisions on the basis of presenting clinical impairments and self-reported pain and disability. The purpose of this systematic review was to quantify clinical impairments, pain and disability in individuals with PTTD compared with controls.

METHODS

Five databases were searched for terms referring to the posterior tibial tendon and flatfoot up to and including 11 March 2018. The systematic review was registered with PROSPERO (CRD: 42016046951). Studies were eligible if they were published in the English language and contained data on clinical impairments, pain or disability compared between participants diagnosed with PTTD and pain-free individuals. Standardised mean differences (SMDs) were calculated where possible and meta-analysis was performed when homogeneity of outcomes allowed.

RESULTS

Ten eligible studies were identified and pooled in the meta-analyses. Strong effects were revealed for poor heel rise endurance (SMD -1.52, 95% CI -2.05 to - 0.99), less forefoot adduction-inversion strength (SMD -1.19, 95% CI -1.68 to - 0.71) and lower arch height (SMD -1.76, 95% CI -2.29 to - 1.23). Compared to controls, individuals with PTTD also had more self-reported stiffness (SMD 1.45, 95% CI 0.91 to 1.99), difficulties caused by foot problems (SMD 1.42, 95% CI 0.52 to 2.33) and social restrictions (SMD1.26, 95% CI 0.25 to 2.27).

CONCLUSION

There is evidence of impaired tibialis posterior capacity and lowered arch height in individuals with PTTD compared to controls. Further to addressing the expected impairments in local tendon function and foot posture, pain, stiffness, functional limitations and social participation restrictions should be considered when managing PTTD.

Reported selection criteria for adult acquired flatfoot deformity and posterior tibial tendon dysfunction: Are they one and the same? A systematic review

BACKGROUND

Posterior tibial tendon dysfunction (PTTD) and adult acquired flatfoot deformity (AAFD) are used interchangeably, although both suggest quite different pathological processes.

OBJECTIVE

To investigate key differences in selection criteria used for inclusion into research studies.

METHODS

An electronic database search was performed from inception to June 2016. All primary research articles with clear inclusion/diagnostic criteria for PTTD or AAFD were included in the review. All criteria were extracted and synthesised into one aggregate list. Frequencies of recurring criteria were calculated and reported for each stage of the conditions.

RESULTS

Of the potentially eligible papers, 148 (65%) did not specify inclusion/selection criteria for PTTD or AAFD and were excluded. Eligibility criteria were reported 82 times in the 80 included papers, with 69 descriptions for PTTD and 13 for AAFD. After synthesis of criteria from all papers, there were 18 key signs and symptoms. Signs and symptoms were considered to be those relating to tendon pathology and those relating to structural deformity. The total number of individual inclusion/diagnostic criteria ranged from 2 to 9. The majority of articles required signs of both tendon dysfunction and structural deformity (84% for AAFD and 81% for PTTD). Across both groups, the most frequently reported criteria were abduction of the forefoot (11.5% of total criteria used), the presence of a flexible deformity (10.2%) and difficulty performing a single leg heel raise (10.0%). This was largely the case for the PTTD articles, whereas the AAFD articles were more focused on postural issues such as forefoot abduction, medial arch collapse, and hindfoot valgus (each 16.7%).

CONCLUSION

As well as synthesising the available literature and providing reporting recommendations, this review has identified that many papers investigating PTTD/AAFD do not state condition-specific selection criteria and that this limits their clinical applicability. Key signs and symptoms of PTTD and AAFD appear similar, except in early PTTD where no structural deformity is present. We recommend that PTTD is the preferred terminology for the condition associated with signs of local tendon dysfunction with pain and/or swelling along the tendon and difficulty with inversion and/or single leg heel raise characterising stage I and difficulty with single leg heel raise and a flexible flatfoot deformity characterizing stage II PTTD. While AAFD may be useful as an umbrella term for acquired flatfoot deformities, the specific associated aetiology should be reported in studies to aid consolidation and implementation of research into practice.

TRIAL REGISTRATION

Prospero ID: 42016046943.

[Degeneration of the posterior tibial tendon : Established and new concepts]

BACKGROUND

The most common cause of degeneration of the posterior tibial tendon is a congenital valgus deformity of the calcaneus. Other associated pathologies are forefoot supination, forefoot abduction and shortening of the gastrocnemius muscle.

DIAGNOSTICS

Loaded x‑rays of the foot in three planes as well as the hindfoot alignment view enable evaluation of the axis of the foot under static loading conditions. The posterior tibial tendon can be imaged with ultrasound and magnetic resonance imaging (MRI). The fatty degeneration of the posterior tibial muscle can be identified in MRI.

CONSERVATIVE THERAPY

Unloading of the posterior tibial tendon can be achieved by orthotics with medial support or braces.

SURGICAL THERAPY

The surgical therapy of the posterior tibial tendon alone has not been proven to be successful. The key element is the correction of the hindfoot valgus by medializing calcaneal osteotomy. Depending on the deformity, an additional lateral lengthening osteotomy of the calcaneus, as well as a dorsal open wedge osteotomy of the medial cuneiform bone (Cotton osteotomy) can additionally be indicated. The transposition of the tendon of the flexor digitorum longus muscle to the navicular bone is used to augment the posterior tibial tendon. Ruptures of the plantar calcaneonavicular ligament are sutured, in addition a sinus tarsi spacer can be implanted to protect medial soft tissues. A shortening of the gastrocnemius muscle is addressed by release of the aponeurosis. First results are published on use of biologically active substances, such as platelet rich plasma.

RESULTS

The correction of the hindfoot deformity as well as the subsequent treatment of the different components of the pathology lead to a significant improvement in foot function. Pre-existing degenerative alterations are limiting factors.

Randomized Controlled Trial Comparing Orthosis Augmented by Either Stretching or Stretching and Strengthening for Stage II Tibialis Posterior Tendon Dysfunction

BACKGROUND

The value of strengthening and stretching exercises combined with orthosis treatment in a home-based program has not been evaluated. The purpose of this study was to compare the effects of augmenting orthosis treatment with either stretching or a combination of stretching and strengthening in participants with stage II tibialis posterior tendon dysfunction (TPTD).

METHODS

Participants included 39 patients with stage II TPTD who were recruited from a medical center and then randomly assigned to a strengthening or stretching treatment group. Excluding 3 dropouts, there were 19 participants in the strengthening group and 17 in the stretching group. The stretching treatment consisted of a prefabricated orthosis used in conjunction with stretching exercises. The strengthening treatment consisted of a prefabricated orthosis used in conjunction with the stretching and strengthening exercises. The main outcome measures were self-report (ie, Foot Function Index and Short Musculoskeletal Function Assessment) and isometric deep posterior compartment strength. Two-way analysis of variance was used to test for differences between groups at 6 and 12 weeks after starting the exercise programs.

RESULTS

Both groups significantly improved in pain and function over the 12-week trial period. The self-report measures showed minimal differences between the treatment groups. There were no differences in isometric deep posterior compartment strength.

CONCLUSIONS

A moderate-intensity, home-based exercise program was minimally effective in augmenting orthosis wear alone in participants with stage II TPTD.

LEVEL OF EVIDENCE

Level I, prospective randomized study.

A population of patient-specific adult acquired flatfoot deformity models before and after surgery

Following IRB approval, a cohort of 3-D rigid-body computational models was created from submillimeter MRIs of clinically diagnosed Adult Acquired Flatfoot Deformity patients and employed to investigate postoperative foot/ankle function and surgical effect during single-leg stance. Models were constrained through physiologic joint contact, passive soft-tissue tension, active muscle force, full body weight, and without idealized joints. Models were validated against patient-matched controls using clinically utilized radiographic angle and distance measures and plantar force distributions in the medial forefoot, lateral forefoot, and hindfoot. Each model further predicted changes in strain for the spring ligament, deltoid ligament, and plantar fascia, as well as joint contact loads for three midfoot joints, the talonavicular, navicular-1st cuneiform, and calcaneocuboid. Radiographic agreement ranged across measures, with average absolute deviations of <5° and <4 mm indicating generally good agreement. Postoperative plantar force loading in patients and models was reduced for the medial forefoot and hindfoot concomitant with increases in the lateral forefoot. Model predicted reductions in medial soft-tissue strain and increases in lateral joint contact load were consistent with in vitro observations and elucidate the biomechanical mechanisms of repair. Thus, validated rigid-body models offer promise for the investigation of foot/ankle kinematics and biomechanical behaviors that are difficult to measure in vivo.

Total and distributed plantar loading in subjects with stage II tibialis posterior tendon dysfunction during terminal stance

BACKGROUND

In subjects with stage II tibialis posterior tendon dysfunction (TPTD), the function of the tibialis posterior muscle is altered and may be associated with a change in total and distributed loading.

METHODS

Thirty subjects with a diagnosis of stage II TPTD and 15 matched control subjects volunteered to participate in a study to examine the total and distributed plantar loading under the foot during the terminal stance phase of gait. Plantar loading, measured as the subject walked barefoot, was assessed using instrumented flexible insoles. A secondary analysis was done to explore the contribution of flatfoot kinematics to plantar loading patterns.

RESULTS

Overall, there was reduced total plantar loading in subjects with stage II TPTD compared with controls. Accounting for differences in total loading, the presence of clinically measured weakness in subjects with TPTD was associated with reduced lateral forefoot loading. Medial longitudinal arch height was significantly correlated with loading patterns but explained only 21% of the variance in observed loading patterns.

CONCLUSION

Subjects with TPTD who are strong exhibited loading patterns similar to controls. Changes in total and distributed loading during terminal stance suggest there are altered ankle mechanics at push-off during the functional task of gait.

CLINICAL RELEVANCE

Strength, in the presence of TPTD, may be important to stabilize the midfoot during gait and might be important in rehabilitation protocols.

Biomechanical and clinical factors related to stage I posterior tibial tendon dysfunction

STUDY DESIGN

Case control.

OBJECTIVES

To investigate differences in arch height, ankle muscle strength, and biomechanical factors in individuals with stage I posterior tibial tendon dysfunction (PTTD) in comparison to healthy individuals.

BACKGROUND

PTTD is a progressive condition, so early recognition and treatment are essential to help delay or reverse the progression. However, no previous studies have investigated stage I PTTD, and no single study has measured static anatomical structure, muscle strength, and gait mechanics in this population.

METHODS

Twelve individuals with stage I PTTD and 12 healthy, age- and gender-matched control subjects, who were engaged in running-related activities, participated in this study. Measurements of arch height index, maximum voluntary ankle invertor muscle strength, and 3-dimensional rearfoot and medial longitudinal arch kinematics during walking were obtained.

RESULTS

The runners with PTTD demonstrated significantly lower seated arch height index (P = .02) and greater (P = .03) and prolonged (P = .05) peak rearfoot eversion angle during gait, compared to the healthy runners. No differences were found in standing arch height index values (P = .28), arch rigidity index (P = .06), ankle invertor strength (P = .49), or peak medial longitudinal arch values (P = .49) between groups.

CONCLUSION

The increased foot pronation is hypothesized to place greater strain on the posterior tibialis muscle, which may partially explain the progressive nature of this condition.

Tendon disorders of the foot and ankle, part 3: the posterior tibial tendon

This article provides a review of posterior tibial tendon pathology and the authors' preferred management. The tibialis posterior musculotendinous unit is the most powerful inverter of the foot and an important dynamic stabilizer of the arch. In the stance phase of the gait cycle, it serves as an initiator of both ankle plantar flexion and subtalar inversion. This creates a rigid midfoot by stabilizing the transverse tarsal joint, and allows for increased power generation by the gastrocsoleus complex through toe-off. Injuries to the posterior tibialis tendon include traumatic laceration and dislocation, as well as tenosynovitis and tendinopathy, which can lead to attenuation and rupture. If these injuries are not addressed, significant clinical deformity and disability can result.

Deep posterior compartment strength and foot kinematics in subjects with stage II posterior tibial tendon dysfunction

BACKGROUND

Tibialis posterior muscle weakness has been documented in subjects with Stage II posterior tibial tendon dysfunction (PTTD) but the effect of weakness on foot structure remains unclear. The association between strength and flatfoot kinematics may guide treatment such as the use of strengthening programs targeting the tibialis posterior muscle.

MATERIALS AND METHODS

Thirty Stage II PTTD subjects (age; 58.1 +/- 10.5 years, BMI 30.6 +/- 5.4) and 15 matched controls (age; 56.5 +/- 7.7 years, BMI 30.6 +/- 3.6) volunteered for this study. Deep Posterior Compartment strength was measured from both legs of each subject and the strength ratio was used to compare each subject's involved side to their uninvolved side. A 20% deficit was defined, a priori, to define two groups of subjects with PTTD. The strength ratio for each group averaged; 1.06 +/- 0.1 (range 0.87 to 1.36) for controls, 1.06 +/- 0.1 (range, 0.89 to 1.25), for the PTTD strong group, and 0.64 +/- 0.2 (range 0.42 to 0.76) for the PTTD weak group. Across four phases of stance, kinematic measures of flatfoot were compared between the three groups using a two-way mixed effect ANOVA model repeated for each kinematic variable.

RESULTS

Subjects with PTTD regardless of group demonstrated significantly greater hindfoot eversion compared to controls. Subjects with PTTD who were weak demonstrated greater hindfoot eversion compared to subjects with PTTD who were strong. For forefoot abduction and MLA angles the differences between groups depended on the phase of stance with significant differences between each group observed at the pre-swing phase of stance.

CONCLUSION

Strength was associated with the degree of flatfoot deformity observed during walking, however, flatfoot deformity may also occur without strength deficits.

CLINICAL RELEVANCE

Strengthening programs may only partially correct flatfoot kinematics while other clinical interventions such as bracing or surgery may also be indicated.

Choosing among 3 ankle-foot orthoses for a patient with stage II posterior tibial tendon dysfunction

STUDY DESIGN

Case report.

BACKGROUND

No head-to-head comparisons of different orthoses for patients with stage II posterior tibial tendon dysfunction (PTTD) have been performed to date. Additionally, the cost of orthoses varies considerably, thus choosing an effective orthosis that is affordable to the patient is largely a trial-and-error process.

CASE DESCRIPTION

A 77-year-old woman was seen with complaints of abnormal foot posture ('my foot is out'), minimal medial foot and ankle pain, and a 3-year history of conservatively managed stage II PTTD. The patient was not able to complete 1 single-limb heel rise on the involved side, while she could complete 3 on the uninvolved side. Ankle strength testing revealed a mild to moderate loss of plantar flexor strength (20%-31% deficit on the involved side), combined with a 22% deficit in isometric ankle inversion and forefoot adduction strength. To assist this patient in managing her flatfoot posture and PTTD, 3 orthoses were considered: an off-the-shelf ankle-foot orthosis (AFO), a custom solid AFO, and a custom articulated AFO. The patient's chief complaint was partly cosmetic (ìmy foot is outî). As decreasing flatfoot kinematics may unload the tibialis posterior muscle, thus prevent the progression of foot deformity, the primary goal of orthotic intervention was to improve flatfoot kinematics. Given the difficulties in clinical approaches to evaluating flatfoot kinematics, a quantitative gait analysis, using a multisegment foot model, was used.

OUTCOMES

In the frontal plane, all 3 orthoses were associated with small changes toward hindfoot inversion. In the sagittal plane, between 2.7 degrees and 6.1 degrees , greater forefoot plantar flexion (raising the medial longitudinal arch) occurred. There were no differences among the orthoses on hindfoot inversion and forefoot plantar flexion. In the transverse plane, the off-the-shelf design was associated with forefoot abduction, the custom solid orthosis was associated with no change, and the custom articulated orthosis was associated with forefoot adduction.

DISCUSSION

Based on gait analysis, the higher-cost custom articulated orthosis was chosen as optimal for the patient. This custom articulated orthosis was associated with the greatest change in flatfoot deformity, assessed using gait analysis. The patient felt it produced the greatest correction in foot deformity. Reducing flatfoot deformity while allowing ankle movement may limit progression of stage II PTTD.

LEVEL OF EVIDENCE

Therapy, level 4.

Foot kinematics during a bilateral heel rise test in participants with stage II posterior tibial tendon dysfunction

STUDY DESIGN

Experimental laboratory study using a cross-sectional design.

OBJECTIVES

To compare foot kinematics, using 3-dimensional tracking methods, during a bilateral heel rise between participants with posterior tibial tendon dysfunction (PTTD) and participants with a normal medial longitudinal arch (MLA).

BACKGROUND

The bilateral heel rise test is commonly used to assess patients with PTTD; however, information about foot kinematics during the test is lacking.

METHODS

Forty-five individuals volunteered to participate, including 30 patients diagnosed with unilateral stage II PTTD (mean +/- SD age, 59.8 +/- 11.1 years; body mass index, 29.9 +/- 4.8 kg/m2) and 15 controls (mean +/- SD age, 56.5 +/- 7.7 years; body mass index, 30.6 +/- 3.6 kg/m2). Foot kinematic data were collected during a bilateral heel rise task from the calcaneus (hindfoot), first metatarsal, and hallux, using an Optotrak motion analysis system and Motion Monitor software. A 2-way mixed-effects analysis of variance model, with normalized heel height as a covariate, was used to test for significant differences between the normal MLA and PTTD groups.

RESULTS

The patients in the PTTD group exhibited significantly greater ankle plantar flexion (mean difference between groups, 7.3 degrees ; 95% confidence interval [CI]: 5.1 degrees to 9.5 degrees ), greater first metatarsal dorsiflexion (mean difference between groups, 9.0 degrees ; 95% CI: 3.7 degrees to 14.4 degrees ), and less hallux dorsiflexion (mean difference, 6.7 degrees ; 95% CI: 1.7 degrees to 11.8 degrees ) compared to controls. At peak heel rise, hindfoot inversion was similar (P = .130) between the PTTD and control groups.

CONCLUSION

Except for hindfoot eversion/inversion, the differences in foot kinematics in participants with stage II PTTD, when compared to the control group, mainly occur as an offset, not an alteration in shape, of the kinematic patterns.

Ankle and foot kinematics associated with stage II PTTD during stance

BACKGROUND

Subjects with stage II posterior tibial tendon dysfunction (PTTD) exhibit abnormal foot kinematics; however, how individual segment kinematics (hindfoot (HF) or first metatarsal (first MET) segments) influence global foot kinematics is unclear. The purpose of this study was to compare foot and ankle kinematics and sagittal plane HF and first MET segment kinematics between stage II PTTD and controls.

MATERIALS AND METHODS

Thirty patients with stage II PTTD and 15 healthy controls were evaluated. Kinematic data from the tibia, calcaneus, and first MET were collected during walking using three dimensional motion analysis techniques. A three-segment foot model (HF, calcaneus; first MET, first metatarsal, and tibia) was used to calculate relative angles (ankle, HF relative to tibia; midfoot, first MET relative to HF) and segment angles (HF and first MET relative to the global). A mixed effect ANOVA model was utilized to compare angles between groups for each variable.

RESULTS

Patients with PTTD showed greater ankle plantarflexion (p = 0.02) by 6.8 degrees to 8.4 degrees prior to or at 74% of stance; greater HF eversion (p < 0.01) across stance (mean difference = 4.5 degrees); and greater first MET dorsiflexion (p < 0.01) across stance (mean difference = 8.8 degrees). HF and first MET segment angles revealed greater HF dorsiflexion (p = 0.01) during early stance and greater first MET dorsiflexion (p = 0.001) across stance.

CONCLUSION

Abnormal HF and first MET segment kinematics separately influence both ankle and midfoot movement during walking in subjects with stage II PTTD.

CLINICAL RELEVANCE

These abnormal kinematics may serve as another measure of response to clinical treatment and/or guide for clinical strategies (exercise, orthotics, and surgery) seeking to improve foot kinematics.