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\u27s 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

The Relationship Between Ankle, Hindfoot, and Forefoot Position and Posterior Tibial Muscle Excursion

Background: The purpose of this study was to examine the relationship of forefoot position in the transverse plane (abduction/adduction), hindfoot position in the frontal plane (eversion/inversion), and ankle position in the sagittal plane (plantarflexion/dorsiflexion) with posterior tibialis (PT) muscle excursion using an in vitro cadaver model. Methods: Seven fresh-frozen cadaver specimens were potted and mounted on a frame. The PT tendon was dissected 15 cm proximal to the medial malleolus, and a 5-kg weight was sutured to the tendon. A six-camera motion analysis system (Optotrak, Northern Digital, Inc.) was used to track three-dimensional (3D) motion of the tibia, calcaneus (hindfoot) and first metatarsal (forefoot) using bone pins. The ankle, hindfoot, and forefoot were manually placed in 24 different ankle and foot positions. A stepwise regression analysis was used to examine the relationship among ankle, hindfoot, and forefoot kinematics and PT muscle excursion. Results: Hindfoot eversion/inversion and forefoot abduction/adduction accounted for 77% of the variance in PT muscle excursion, with small contributions from ankle plantarflexion/dorsiflexion (5.7%) and forefoot plantarflexion/dorsiflexion (1.9%). A combined regression equation applied to individual specimens resulted in average errors of less than 2.5 mm. Conclusions: This study supports the hypothesis that PT muscle excursion can be estimated using specific foot and ankle kinematic variables. Further, these data suggest that hindfoot eversion and forefoot abduction account for most of the variance in PT muscle excursion and are theorized to be important to control clinically altering the length of the posterior tibial muscle

Adult-Acquired Flatfoot Deformity and Age-Related Differences in Foot and Ankle Kinematics During the Single-Limb Heel-Rise Test

STUDY DESIGN: Cross-sectional laboratory study. OBJECTIVE: To compare single-limb heel-rise performance and foot-ankle kinematics between persons with stage 2 adult-acquired flatfoot deformity (AAFD) and healthy controls. BACKGROUND: The inability to perform a single-limb heel rise is considered a positive functional diagnostic test for AAFD. However, which foot motions contribute to poor performance of this task are not known. METHODS: Fifty individuals participated in this study, 20 with stage 2 AAFD (mean +/- SD age, 57.6 +/- 11.3 years), and 15 older participants (age, 56.8 +/- 5.3 years) and 15 younger participants (age, 22.2 +/- 2.4 years) without AAFD as control groups. Forefoot (sagittal plane) and rearfoot (sagittal and frontal planes) kinematics were collected using a 3-D motion analysis system. Heel-rise performance (heel height) and kinematics (joint angles, excursions) were evaluated. One-way and 2-way analyses of variance were used to examine differences in heel-rise performance and kinematics between groups. RESULTS: Individuals with AAFD and older controls demonstrated lower heel-rise height than those in the younger control group (P\u3c.001). Persons with AAFD demonstrated higher degrees of first metatarsal dorsiflexion (P\u3c.001), lower ankle plantar flexion (P\u3c.001), and higher subtalar eversion (P = .027) than those in the older control group. Persons with AAFD demonstrated lower ankle excursion (P\u3c.001) and first metatarsal excursion (P\u3c.001) than those in the older control group, but no difference in subtalar excursion (P = .771). CONCLUSION: Persons with stage 2 AAFD did not achieve sufficient heel height during a single-leg heel rise. Both forefoot and rearfoot kinematics in the sagittal plane, as opposed to the frontal plane, contributed to the lower heel height in participants with stage 2 AAFD. Older controls demonstrated lower heel-rise height than younger controls, indicating that clinical expectations of heel-rise performance may need to be adjusted for age

Altered Tendon Characteristics and Mechanical Properties Associated with Insertional Achilles Tendinopathy

Study Design: Case-control laboratory study. Objectives: To compare tendon characteristics (shape, composition) and mechanical properties (strain, stiffness) on the involved side of participants with insertional Achilles tendinopathy (IAT) to the uninvolved side and to controls, and to examine if severity of tendon pathology is associated with severity of symptoms during function. Background: Despite the severity and chronicity of IAT, the quality of theoretical evidence available to guide the development of exercise interventions is low. While tendon pathology of midportion Achilles tendinopathy has been described, there are few studies specific to IAT. Methods: Twenty individuals with unilateral IAT and 20 age- and sex-matched controls volunteered to participate. Ultrasound imaging was used to quantify changes in tendon shape (diameter) and composition (echogenicity). A combination of ultrasound and dynamometry was used to measure tendon mechanical properties (strain and stiffness) during passive ankle rotation toward dorsiflexion. Generalized estimating equations were used to examine the association between IAT, alterations in tendon properties, and participant demographics. Pearson correlation was used to examine the association between severity of tendon pathology and severity of symptoms (Victorian Institute of Sport Assessment-Achilles). Results: The side with IAT had a larger tendon diameter (P Conclusion: Ultrasound imaging combined with dynamometry can discriminate alterations in tendon shape, composition, and mechanics in participants with IAT. Future clinical trials for IAT may consider strategies to alter tendon characteristics and restore tendon mechanic

Is there a Difference in Outcomes between Patients who Received a Double or Triple Arthrodesis for Hindfoot Arthritis?

Introduction/Purpose: Triple arthrodesis has historically been considered the standard of treatment for arthritis of the hindfoot with or without deformity. The complications of this surgery including non-union, malunion, nerve injury, infection and wound healing problems can occur at any of the three joints. Double arthrodesis is capable of producing a similar reduction in degrees of motion and correction of foot deformity but may also cause less patient morbidity in regard to these complications due to one less joint being incorporated into the fusion procedure. What is unknown is the patient reported outcomes, specifically physical function (PF) and pain interference (PI) between these two procedures. The purpose of this study is to evaluate the clinical outcomes for hindfoot deformity using a triple compared to a double arthrodesis

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 \u3c 0.01) across stance (mean difference = 4.5 degrees); and greater first MET dorsiflexion (p \u3c 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. Copyright © 2009 by the American Orthopaedic Foot & Ankle Society

Clinical outcomes and static and dynamic assessment of foot posture after Lateral column lengthening procedure

Background: Lateral column lengthening (LCL) has been shown to radiographically restore the medial longitudinal arch. However, the impact of LCL on foot function during gait has not been reported using validated clinical outcomes and gait analysis. Methods: Thirteen patients with a stage II flatfoot who had undergone unilateral LCL surgery and 13 matched control subjects completed self-reported pain and functional scales as well as a clinical examination. A custom force transducer was used to establish the maximum passive range of motion of first metatarsal dorsiflexion at 40 N of force. Foot kinematic data were collected during gait using 3-dimensional motion analysis techniques. Results: Radiographic correction of the flatfoot was achieved in all cases. Despite this, most patients continued to report pain and dysfunction postoperatively. Participants post LCL demonstrated similar passive and active movement of the medial column when we compared the operated and the nonoperated sides. However, participants post LCL demonstrated significantly greater first metatarsal passive range of motion and first metatarsal dorsiflexion during gait than did controls (P \u3c.01 for all pairwise comparisons). Conclusion: Patients undergoing LCL for correction of stage II adult-Acquired flatfoot deformity experience mixed outcomes and similar foot kinematics as the uninvolved limb despite radiographic correction of deformity. These patients maintain a low arch posture similar to their uninvolved limb. The consequence is that first metatarsal movement operates at the end range of dorsiflexion and patients do not obtain full hindfoot inversion at push-off. Longitudinal data are necessary to make a more valid comparison of the effects of surgical correction measured using radiographs and dynamic foot posture during gait. Level of Evidence: Level III, comparative series. © The Author(s) 2013

2016 J. Leonard Goldner Award - Can Initial PROMIS Scores Predict Outcome for Foot and Ankle Patients?

Category: Other Introduction/Purpose: The use of patient reported outcomes continues to expand beyond the scope of clinical research to involve standard of care assessments across orthopaedic practices. It is currently unclear how to interpret and apply this information in the daily care of patients. We examined the relationship between patient reported outcomes (PROMIS Physical Function, Pain Interference and Depression scores) obtained at initial visit as a predictor of outcome at a minimum of 7 month follow up. Methods: Prospective collection of all consecutive patient visits to the University of Rochester Orthopaedic foot and ankle clinic was initiated on April 2015. Data through December 2015 was classified as new or follow up and operative or non-operative based on ICD-9 and CPT codes. 17,019 patient visits were collected on 7,265 patients, of which 4,213 were new patients. PROMIS physical function, pain interference, and depression scores were assessed at initial and follow up visits. Only patients with a minimum of 7 months (mean 8.2) follow up who completed all PROMIS domains were included, resulting in 262 patients (69 operative, 193 non-operative). PROMIS scores are normalized to a US population with an average score of 50 and a standard deviation of 10. Statistical analysis using student t-tests and linear regression were performed to determine if the initial PROMIS scores were predictive of patient reported outcomes at final follow up. Results: There were no differences between operative and non-operative treatment groups in initial PROMIS scores or change in scores at follow up (p>0.40). Patients with higher baseline pain were likely to experience less pain over time (r=0.63, p < 0.01). Similarly, patients with higher baseline depression were likely to experience decreased depression over time (r =0.52, p < 0.01). Patients with lower baseline physical function were likely to improve over time whereas patients with higher baseline physical function were likely to worsen over time (r=0.68, p< 0.01). Specifically, all patients with baseline physical function score less than 28 improved over time, while all patients with a score greater than 52 worsened (Figure 1). Conclusion: Physical function, pain, and depression trends did not vary between operative and non-operative patients at 8.2 month follow up. Patients with high initial pain and depression were likely to have improvements in pain and depression over time. Similarly, patients with low initial physical function were likely to have improved physical function. However, despite treatment, patients with above average initial physical function did not experience improvement in physical function, suggesting these patients are more challenging to treat. This information demonstrates that baseline patient reported outcomes are predictive of improvement in outcomes over time, and could assist in the treatment decision process

Noninvasive Measurement of Normal Foot and Ankle Joint Reaction Force

Category: Basic Sciences/Biologics Introduction/Purpose: Various biomechanical studies have examined pressure changes across the foot and ankle joints. However, most of these studies disrupted the capsuloligamentous complex surrounding the joint to insert pressure sensors, compromising the integrity of the natural joint structure and the accuracy of biomechanical assessments. This is the first noninvasive study to report measurement of natural joint reaction forces (JRF) across the foot and ankle while preserving all soft tissue structures. Since articular surfaces experience equal and opposing compression forces, we aimed to evaluate the distraction force needed to overcome these compression forces. Methods: Ten fresh-frozen cadavers of the lower extremity were obtained that were disarticulated at the knee joint. Steinmann pins were percutaneously placed across the distal tibia, and the center of the talus, navicular, cuboid, and calcaneus while preserving all surrounding soft tissues. A custom fixation device was utilized in conjunction with a tensile testing machine to allow distraction in line with the axis of the tibiotalar, subtalar, talonavicular (TN), and calcaneocuboid (CC) joints. Displacement was measured as distance between Steinmann pins on either side of the joint examined. Under progressive axial distraction, displacement and force were measured. Best-fit polynomials were calculated to fit the force-displacement curves. The inflection point, representing the joint reaction force (JRF) where distraction forces across the joint equal the compression forces, was calculated for each curve. Results: All force-displacement curves demonstrated an inflection point. Prior to the inflection point, relatively large increases in distraction force resulted in minimal displacement. Once the inflection point was reached, relatively small increases in distraction force resulted in large increases in displacement. Each cadaver was measured three times with high reproducibility. The mean JRF were tibiotalar 33.8 N [standard deviation (SD) 10], subtalar 18.2 N (SD 12), TN 13.3 N (SD 4), and CC 14.7 N (5.8). Conclusion: We present the first application of a reliable and noninvasive method of measuring JRF of the foot and ankle joints. In the medium or small joints, dissection of the capsule and surrounding ligaments can significantly alter joint stability and biomechanics. By preserving all the periarticular soft tissues, this experimental model will allow future investigation of biomechanical changes of pathologic states and efficacy of surgical intervention under conditions that most accurately reflect the in vivo state