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Ledoux WR. Role of Robotic Gait Simulators in Elucidating Foot and Ankle Pathomechanics. Foot Ankle Clin 2023; 28:45-62. [PMID: 36822688 DOI: 10.1016/j.fcl.2022.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Testing with cadaveric foot and ankle specimens began as mechanical techniques to study foot function and then evolved into static simulations of specific instances of gait, before technologies were eventually developed to fully replicate the gait cycle. This article summarizes the clinical applications of dynamic cadaveric gait simulation, including foot bone kinematics and joint function, muscle function, ligament function, orthopaedic foot and ankle pathologies, and total ankle replacements. The literature was reviewed and an in-depth summary was written in each section to highlight one of the more sophisticated simulators. The limitations of dynamic cadaveric simulation were also reviewed.
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Affiliation(s)
- William R Ledoux
- Center for Limb Loss and MoBility (CLiMB), VA Puget Sound Health Care System, ms 151, 1660 South Columbian Way, Seattle, WA 98108, USA; Department of Mechanical Engineering, University of Washington, Seattle, WA, USA; Department of Orthopaedics & Sports Medicine, University of Washington, Seattle, WA, USA.
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Dussa CU, Böhm H, Döderlein L, Fujak A. Treatment of spastic varus/ equinovarus foot with split-tendon transfers in cerebral palsy: How does it affect the hindfoot motion? Gait Posture 2022; 92:343-350. [PMID: 34920359 DOI: 10.1016/j.gaitpost.2021.10.042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 09/10/2021] [Accepted: 10/25/2021] [Indexed: 02/02/2023]
Abstract
INTRODUCTION The flexible spastic varus foot in cerebral palsy is commonly corrected by split-tendon transfer of tibialis anterior or tibialis posterior. These tendon transfers are said to preserve hindfoot motion, which is until now not been proven. Therefore, the aim of the study was to show the hindfoot motion following split-tendon transfer in comparison to a midtarsal arthrodesis. MATERIALS AND METHODS A retrospective study was done on patients with flexible spastic varus foot in cerebral palsy who underwent a combined split-tendon transfer of tibialis anterior and posterior. Patients with a rigid foot deformity underwent a midfoot arthrodesis. These children and normal children served as controls. An instrumented gait analysis was done in all patients before and at follow-up. A statistical analysis was done using 2-factor ANOVA with repeated measures on time. RESULTS Thirteen children underwent a combined split-tendon transfers of tibialis anterior and posterior muscles and 14 children midtarsal arthrodesis. The mean follow-up was 2.4 (SD=0.8) years for flexible varus foot and 1.9 (SD=0.7) years for rigid foot deformity. The preoperative hindfoot range of motion in eversion-inversion was 54% and 49% of TD controls in flexible varus foot and rigid foot deformity respectively. At follow-up, it reduced further to 45% and 42% of TD controls in the respective groups. CONCLUSION Both flexible and rigid hindfoot deformity reduced the hindfoot motion. However following surgery, the hindfoot motion reduced further and was identical in both groups independent of the type of surgery. This indicates a tenodesis-effect of split-tendon transfers on the hindfoot.
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Affiliation(s)
- Chakravarthy U Dussa
- Department of Paediatric Orthopaedics, Orthopaedische Kinderklinik, Bernauerstrasse 18, D-83229 Aschau i. Chiemgau, Bavaria, Germany.
| | - Harald Böhm
- Gait Laboratory, Orthopaedische Kinderklinik, Bernauerstrasse 18, D-83229 Aschau i. Chiemgau, Bavaria, Germany
| | - Leonhard Döderlein
- Pediatric Orthopaedic Surgeon, Aukamm Klinik, Leibnizstraße 21, 65191 Wiesbaden, Germany
| | - Albert Fujak
- Department of Trauma and Orthopaedic Surgery, Pediatric and Neuro Orthopaedics, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Krankenhausstr. 12, D-91054 Erlangen, Bavaria, Germany
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Abstract
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.
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Affiliation(s)
- Beat Hintermann
- Center of Excellence for Foot and Ankle Surgery, Kantonsspital Baselland, Rheinstrasse 26, CH-4410 Liestal, Switzerland.
| | - Roxa Ruiz
- Center of Excellence for Foot and Ankle Surgery, Kantonsspital Baselland, Rheinstrasse 26, CH-4410 Liestal, Switzerland
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Affiliation(s)
- Markus Knupp
- 1 Department of Orthopaedic Surgery, Kantonsspital Baselland, Switzerland
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Krähenbühl N, Tschuck M, Bolliger L, Hintermann B, Knupp M. Orientation of the Subtalar Joint: Measurement and Reliability Using Weightbearing CT Scans. Foot Ankle Int 2016; 37:109-14. [PMID: 26293157 DOI: 10.1177/1071100715600823] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND Up to 60% of patients with an osteoarthritic ankle joint develop talar tilt with progression of the osteoarthritic process. The configuration of the subtalar joint, in particular the posterior facet, may contribute to the development of this wear pattern. Recently, the subtalar vertical angle (SVA) was used to describe the posterior facet of the subtalar joint in the frontal plane. The aim of this work was to analyze if the orientation of the subtalar joint may influence the type of asymmetric ankle osteoarthritis. METHODS In total, 60 ankles were retrospectively analyzed including 40 osteoarthritic patients and 20 healthy controls. The osteoarthritic ankles were divided into 4 groups: varus ankle joints with (incongruent) or without (congruent) a tilted talus and valgus ankle joints with (incongruent) or without (congruent) a tilted talus. The orientation of the subtalar joint was described using the SVA. The SVA was determined for every patient using weightbearing CT scans. Additionally, the inter- and intraobserver reliability was assessed using intraclass correlation coefficients (ICCs). RESULTS The inter- and intraobserver reliability was excellent (ICC > 0.989 and >0.975, respectively). The varus groups (incongruent and congruent) had significantly lower SVA values, that is, more varus orientation of the subtalar joint than the valgus groups (P < .05). The SVA of the control group was between the values of the varus and valgus ankles. CONCLUSION The SVA provided a reliable and consistent method to assess the varus/valgus configuration of the posterior facet of the subtalar joint. In our cohort, varus osteoarthritis of the ankle joint occurred with varus orientation of the subtalar joint whereas in patients with valgus osteoarthritis, valgus orientation of the subtalar joint was found. Our data suggest that the subtalar joint orientation may be a risk factor for the development of ankle joint osteoarthritis. LEVEL OF EVIDENCE Level III, retrospective case control study.
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Affiliation(s)
- Nicola Krähenbühl
- Clinic for Orthopaedic and Trauma Surgery, Kantonsspital Baselland, Switzerland
| | - Michael Tschuck
- Clinic for Orthopaedic and Trauma Surgery, Kantonsspital Baselland, Switzerland
| | - Lilianna Bolliger
- Clinic for Orthopaedic and Trauma Surgery, Kantonsspital Baselland, Switzerland
| | - Beat Hintermann
- Clinic for Orthopaedic and Trauma Surgery, Kantonsspital Baselland, Switzerland
| | - Markus Knupp
- Clinic for Orthopaedic and Trauma Surgery, Kantonsspital Baselland, Switzerland
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The split anterior tibialis tendon transfer procedure for spastic equinovarus foot in children with cerebral palsy: results and factors associated with a failed outcome. INTERNATIONAL ORTHOPAEDICS 2015; 39:1593-8. [DOI: 10.1007/s00264-015-2793-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 04/05/2015] [Indexed: 11/25/2022]
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Knutsen AR, Avoian T, Sangiorgio SN, Borkowski SL, Ebramzadeh E, Zionts LE. How do different anterior tibial tendon transfer techniques influence forefoot and hindfoot motion? Clin Orthop Relat Res 2015; 473:1737-43. [PMID: 25421955 PMCID: PMC4385364 DOI: 10.1007/s11999-014-4057-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 11/10/2014] [Indexed: 01/31/2023]
Abstract
BACKGROUND Idiopathic clubfoot correction is commonly performed using the Ponseti method and is widely reported to provide reliable results. However, a relapsed deformity may occur and often is treated in children older than 2.5 years with repeat casting, followed by an anterior tibial tendon transfer. Several techniques have been described, including a whole tendon transfer using a two-incision technique or a three-incision technique, and a split transfer, but little is known regarding the biomechanical effects of these transfers on forefoot and hindfoot motion. QUESTIONS/PURPOSE We used a cadaveric foot model to test the effects of three tibialis anterior tendon transfer techniques on forefoot positioning and production of hindfoot valgus. METHODS Ten fresh-frozen cadaveric lower legs were used. We applied 150 N tension to the anterior tibial tendon, causing the ankle to dorsiflex. Three-dimensional motions of the first metatarsal, calcaneus, and talus relative to the tibia were measured in intact specimens, and then repeated after each of the three surgical techniques. RESULTS Under maximum dorsiflexion, the intact specimens showed 6° (95% CI, 2.2°-9.4°) forefoot supination and less than 3° (95% CI, 0.4°-5.3°) hindfoot valgus motion. All three transfers provided increased forefoot pronation and hindfoot valgus motion compared with intact specimens: the three-incision whole transfer provided 38° (95% CI, 33°-43°; p < 0.01) forefoot pronation and 10° (95% CI, 8.5°-12°; p < 0.01) hindfoot valgus; the split transfer, 28° (95% CI, 24°-32°; p < 0.01) pronation, 9° (95% CI, 7.5°-11°; p < 0.01) valgus; and the two-incision transfer, 25° (95% CI, 20°-31°; p < 0.01) pronation, 6° (95% CI, 4.2°-7.8°; p < 0.01) valgus. CONCLUSION All three techniques may be useful and deliver varying degrees of increased forefoot pronation, with the three-incision whole transfer providing the most forefoot pronation. Changes in hindfoot motion were small. CLINICAL RELEVANCE Our study results show that the amount of forefoot pronation varied for different transfer methods. Supple dynamic forefoot supination may be treated with a whole transfer using a two-incision technique to avoid overcorrection, while a three-incision technique or a split transfer may be useful for more resistant feet. Confirmation of these findings awaits further clinical trials.
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Affiliation(s)
- A. R. Knutsen
- />Department of Biomedical Engineering, University of California Los Angeles, Los Angeles, CA USA
- />The J. Vernon Luck, Sr. M.D. Orthopaedic Research Center, Orthopaedic Institute for Children, 403 West Adams Boulevard, Los Angeles, CA 90007 USA
| | - T. Avoian
- />Orthopaedic Institute for Children, Los Angeles, CA 90007 USA
| | - S. N. Sangiorgio
- />The J. Vernon Luck, Sr. M.D. Orthopaedic Research Center, Orthopaedic Institute for Children, 403 West Adams Boulevard, Los Angeles, CA 90007 USA
- />Department of Orthopaedic Surgery, University of California, Los Angeles, Los Angeles, CA USA
| | - S. L. Borkowski
- />Department of Biomedical Engineering, University of California Los Angeles, Los Angeles, CA USA
- />The J. Vernon Luck, Sr. M.D. Orthopaedic Research Center, Orthopaedic Institute for Children, 403 West Adams Boulevard, Los Angeles, CA 90007 USA
| | - E. Ebramzadeh
- />The J. Vernon Luck, Sr. M.D. Orthopaedic Research Center, Orthopaedic Institute for Children, 403 West Adams Boulevard, Los Angeles, CA 90007 USA
- />Department of Orthopaedic Surgery, University of California, Los Angeles, Los Angeles, CA USA
| | - L. E. Zionts
- />Department of Orthopaedic Surgery, University of California, Los Angeles, Los Angeles, CA USA
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Krzak JJ, Corcos DM, Damiano DL, Graf A, Hedeker D, Smith PA, Harris GF. Kinematic foot types in youth with equinovarus secondary to hemiplegia. Gait Posture 2015; 41:402-8. [PMID: 25467429 PMCID: PMC4574499 DOI: 10.1016/j.gaitpost.2014.10.027] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Revised: 09/05/2014] [Accepted: 10/31/2014] [Indexed: 02/02/2023]
Abstract
BACKGROUND Elevated kinematic variability of the foot and ankle segments exists during gait among individuals with equinovarus secondary to hemiplegic cerebral palsy (CP). Clinicians have previously addressed such variability by developing classification schemes to identify subgroups of individuals based on their kinematics. OBJECTIVE To identify kinematic subgroups among youth with equinovarus secondary to CP using 3-dimensional multi-segment foot and ankle kinematics during locomotion as inputs for principal component analysis (PCA), and K-means cluster analysis. METHODS In a single assessment session, multi-segment foot and ankle kinematics using the Milwaukee Foot Model (MFM) were collected in 24 children/adolescents with equinovarus and 20 typically developing children/adolescents. RESULTS PCA was used as a data reduction technique on 40 variables. K-means cluster analysis was performed on the first six principal components (PCs) which accounted for 92% of the variance of the dataset. The PCs described the location and plane of involvement in the foot and ankle. Five distinct kinematic subgroups were identified using K-means clustering. Participants with equinovarus presented with variable involvement ranging from primary hindfoot or forefoot deviations to deformtiy that included both segments in multiple planes. CONCLUSION This study provides further evidence of the variability in foot characteristics associated with equinovarus secondary to hemiplegic CP. These findings would not have been detected using a single segment foot model. The identification of multiple kinematic subgroups with unique foot and ankle characteristics has the potential to improve treatment since similar patients within a subgroup are likely to benefit from the same intervention(s).
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Affiliation(s)
- Joseph J. Krzak
- Midwestern University, Physical Therapy Program, College of Health Sciences, 555 31st Street, Downers Grove, IL, United States,Shriners Hospitals for Children®-Chicago, 2211 North Oak Park Avenue, Chicago, IL, United States,Corresponding author at: Midwestern University, Physical Therapy Program, College of Health Sciences, 555 31st Street, Downers Grove, IL, United States. Tel.: +1630 960-3942; fax: +1 630 515-7224. (J.J. Krzak)
| | - Daniel M. Corcos
- Northwestern University Feinberg School of Medicine, Department of Physical Therapy and Human Movement Sciences, 645 North Michigan Avenue, Chicago, IL, United States
| | - Diane L. Damiano
- National Institutes of Health, Functional & Applied Biomechanics Section, 10 Center Drive, Bethesda, MD, United States
| | - Adam Graf
- Shriners Hospitals for Children®-Chicago, 2211 North Oak Park Avenue, Chicago, IL, United States
| | - Donald Hedeker
- University of Chicago, Department of Public Health Sciences, 5841 South Maryland Avenue, Chicago, IL, United States
| | - Peter A. Smith
- Shriners Hospitals for Children®-Chicago, 2211 North Oak Park Avenue, Chicago, IL, United States,RUSH University Medical Center, Department of Orthopaedic Surgery, College of Medicine, 1611 West Harrison Street, Chicago, IL, United States
| | - Gerald F. Harris
- Shriners Hospitals for Children®-Chicago, 2211 North Oak Park Avenue, Chicago, IL, United States,Orthopaedic & Rehabilitation Engineering Center (OREC), Marquette University/Medical College of Wisconsin, 735 North 17th Street, Milwaukee, WI, United States
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Affiliation(s)
- Beat Hintermann
- Clinic of Orthopaedic Surgery, Kantonsspital Liestal, Liestal, Switzerland.
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McCullough MB, Ringleb SI, Arai K, Kitaoka HB, Kaufman KR. Moment arms of the ankle throughout the range of motion in three planes. Foot Ankle Int 2011; 32:300-6. [PMID: 21477550 DOI: 10.3113/fai.2011.0300] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND The moment, a force applied at a distance, is responsible for movement and balance. A key component of the moment is the moment arm. The moment arms of nine muscles surrounding the ankle complex during motion in three planes, were studied. MATERIALS AND METHODS Five cadaveric feet were mounted in a testing device that created moments in the sagittal, coronal and transverse planes. Axial and tendon loads were applied as the foot was passively moved in these planes. Tendon excursions and bone kinematics were monitored. The moment arm was calculated using the tendon excursion method and averaged across all specimens. RESULTS The largest average moment arm during plantarflexion/dorsiflexion, was the Achilles (mean, 53.1; SD, 5.1 mm). During internal/external rotation the largest moment arm was the peroneus brevis (mean, 20.5; SD, 6.4 mm). During inversion/eversion, the largest moment arm was the peroneus longus (31 mm; SD, 2.3 mm). CONCLUSION This study quantified the functional moment arms of nine tendons of the ankle/foot. The involvement of multiple tendons in multiple planes of motion should be considered in computational models and when deciding treatments. CLINICAL RELEVANCE The correlation between moment arms and muscle function has significant effects on treatment efficacy. Information on the balance of moments around the ankle will assist in achieving optimal biomechanical behavior following operative treatments.
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Hunter BV, Thelen DG, Dhaher YY. A three-dimensional biomechanical evaluation of quadriceps and hamstrings function using electrical stimulation. IEEE Trans Neural Syst Rehabil Eng 2009; 17:167-75. [PMID: 19193516 DOI: 10.1109/tnsre.2009.2014235] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Neurological disorders such as stroke impair locomotor control and result in abnormal 3-D gait kinematics. Establishment of effective rehabilitation strategies requires an understanding of how individual muscles contribute to pathological movement. Forward dynamic simulations account for complexities of interjoint coupling and can be used to predict dynamic muscle function. However to date, limited experimental validations of dynamic models have been performed. Our objective was to measure 3-D movement induced by the biceps femoris (BF), rectus femoris (RF), and vastus lateralis (VL) in limb configurations corresponding to the swing phase of gait, and to assess the biomechanical factors that affect dynamic function. Subjects were positioned in a robotic gait orthosis that included a compliant interface. Electrical stimulation was introduced into individual muscles while induced hip and knee joint movements were recorded. Measured hip to knee sagittal plane acceleration ratios were consistent with dynamic musculoskeletal model simulations. However RF and VL induced substantially larger frontal plane hip movements than model-based predictions. Sensitivity analyses on musculoskeletal model parameters revealed that muscle function depends primarily on moment arm assumptions. Though generic musculoskeletal models are suitable for predicting sagittal plane muscle function, improvements in moment arm accuracy are essential for investigation of 3-D pathological gait.
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Affiliation(s)
- Betsy V Hunter
- Biomedical Engineering Department, Northwestern University, Evanston, IL 60208 USA.
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Lee SS, Piazza SJ. Inversion–eversion moment arms of gastrocnemius and tibialis anterior measured in vivo. J Biomech 2008; 41:3366-70. [DOI: 10.1016/j.jbiomech.2008.09.029] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2008] [Revised: 09/13/2008] [Accepted: 09/23/2008] [Indexed: 11/29/2022]
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Landsman A, Cook E, Cook J. Tenotomy and tendon transfer about the forefoot, midfoot and hindfoot. Clin Podiatr Med Surg 2008; 25:547-69, vii. [PMID: 18722899 DOI: 10.1016/j.cpm.2008.05.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Tendon lengthening and transfer are essential surgical procedures for every foot and ankle surgeon to master, because they are useful in restoring balance and correcting flexible foot deformities. These techniques are even more useful in treating the high-risk patient, because they involve minimal soft-tissue injury and maximum preservation of vascularity. The primary goal of this article is to supplement the foot and ankle surgeon's options for treating static and dynamic foot deformities in the high-risk patient by discussing useful tendon lengthening and transfer procedures about the forefoot, midfoot, and hindfoot.
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An Algorithm for Automated Analysis of Ultrasound Images to Measure Tendon Excursion in Vivo. J Appl Biomech 2008; 24:75-82. [DOI: 10.1123/jab.24.1.75] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The accuracy of an algorithm for the automated tracking of tendon excursion from ultrasound images was tested in three experiments. Because the automated method could not be tested against direct measurements of tendon excursion in vivo, an indirect validation procedure was employed. In one experiment, a wire “phantom” was moved a known distance across the ultrasound probe and the automated tracking results were compared with the known distance. The excursion of the musculotendinous junction of the gastrocnemius during frontal and sagittal plane movement of the ankle was assessed in a single cadaver specimen both by manual tracking and with a cable extensometer sutured to the gastrocnemius muscle. A third experiment involved estimation of Achilles tendon excursion in vivo with both manual and automated tracking. Root mean squared (RMS) error was calculated between pairs of measurements after each test. Mean RMS errors of less than 1 mm were observed for the phantom experiments. For the in vitro experiment, mean RMS errors of 8–9% of the total tendon excursion were observed. Mean RMS errors of 6–8% of the total tendon excursion were found in vivo. The results indicate that the proposed algorithm accurately tracks Achilles tendon excursion, but further testing is necessary to determine its general applicability.
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Hui HEJ, Beals TC, Brown NAT. Influence of tendon transfer site on moment arms of the flexor digitorum longus muscle. Foot Ankle Int 2007; 28:441-7. [PMID: 17475138 DOI: 10.3113/fai.2007.0441] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND Adult acquired flatfoot is a common condition that leads to significant morbidity. Along with bony procedures to operatively treat this condition, transfer of the flexor digitorum longus (FDL) tendon to the medial cuneiform or navicular is routinely performed. The goal of this tendon transfer is to increase the capacity of the FDL to invert the hindfoot and control the transverse tarsal joints. However, it is not known whether this biomechanical goal is met or whether one transfer site produces a larger mechanical advantage compared to another site. The purpose of this study was to calculate FDL muscle moment arms at the hindfoot with two clinically relevant transfer locations to quantify the change in mechanical advantage of the FDL after tendon transfer. METHODS In seven cadaver specimens, muscle moment arms of the FDL with respect to hindfoot motion were measured using the tendon excursion method before and after the FDL was transferred to the plantar aspect of the navicular and medial cuneiform. The position and orientation of the foot and excursion of the FDL tendon were measured with an optoelectronic measurement system. RESULTS The FDL moment arm did not increase after tendon transfer to either the medial cuneiform or navicular when compared to its native site. There were significant decreases in FDL moment arm when transferred from its native site to the medial cuneiform (56% decrease, p=0.018) and navicular (46% decrease, p=0.026). CONCLUSIONS In contrast to the clinical proposition that FDL transfer to the navicular or medial cuneiform increases this muscle's mechanical advantage to invert the hindfoot, this cadaver study suggests that, to the contrary, FDL muscle moment arms decrease after tendon transfer.
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Affiliation(s)
- Hou-en J Hui
- Department of Bioengineering, University of Utah, Salt Lake City, UT 84108, USA
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Abstract
Knowledge of the location of the subtalar joint axis in individual patients would permit clinical assessment of the forces and moments that produce frontal-plane foot and ankle deformities. Biomechanical analysis of the subtalar joint is hindered, however, by the inaccessibility of the talus, which makes locating the joint axis difficult, and by the high degree of intersubject anatomic variation. This article discusses work done with cadaver specimens and using invasive methods in vivo that has enhanced our understanding of the mechanics of the subtalar joint and its function during gait. Also reviewed are investigations of the actions of muscles that cross the subtalar joint.
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Affiliation(s)
- Stephen J Piazza
- Department of Kinesiology, Mechanical & Nuclear Engineering, The Pennsylvania State University, University Park, PA 16802, USA.
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Gabrieli APT, Stein HE, Machado Neto L. Tratamento do pé varo espástico através da hemitransposição do tendão do tibial posterior. ACTA ORTOPEDICA BRASILEIRA 2004. [DOI: 10.1590/s1413-78522004000400002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Foram avaliados dez pacientes (12 pés) com paralisia cerebral espástica submetidos à hemitransposição do tendão do tibial posterior para correção da deformidade em varo do pé. Quatro pacientes eram do sexo feminino e 6 do sexo masculino. A idade média dos pacientes foi de 8 anos e 9 meses. Seis pacientes apresentavam paralisia cerebral espástica hemiplégica; 2,diplégica e 2 pacientes, paralisia cerebral tipo misto. O tempo médio de seguimento foi de 26 meses. Cirurgias associadas foram realizadas em 11 pés (92%). Oito pés apresentaram bom resultado (67%), três pés (25%), resultado regular e um pé (8%), mau resultado. Nenhum dos pés desenvolveu deformidade em calcâneo-valgo. Os resultados regulares e mau estiveram associados principalmente à insuficiência do músculo tibial anterior que levou à necessidade de manutenção do uso de órtese no pós-operatório, à influência de outras forças deformantes no pé além do músculo tibial posterior e à presença de deformidade óssea estruturada. Os autores concluem que a técnica de hemitransposição do tendão do tibial posterior, associada a outras cirurgias quando necessário, tem bom resultado na correção da deformidade em varo do pé na paralisia cerebral; desde que sejam determinadas corretamente as características dinâmicas da deformidade e eventuais deformidades associadas sejam tratadas de forma apropriada, concomitantemente.
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Piazza SJ, Adamson RL, Moran MF, Sanders JO, Sharkey NA. Effects of tensioning errors in split transfers of tibialis anterior and posterior tendons. J Bone Joint Surg Am 2003; 85:858-65. [PMID: 12728036 DOI: 10.2106/00004623-200305000-00013] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND Split transfers of the tibialis anterior and posterior tendons are commonly performed to address hindfoot varus deformities in patients with cerebral palsy, stroke, or brain injury. Poor outcomes from these procedures are often attributed to a failure to tension the transferred tendon properly, but the mechanical effects of this aspect of the procedure have not been quantified, to our knowledge. The purpose of the present study was to use a cadaver model to examine changes in the actions of these muscles that occur when the tensions in the halves of the split tendon are intentionally balanced or unbalanced to varying degrees. METHODS Tendon excursion was measured in seven cadaveric specimens before and after split tendon transfer with experimentally controlled tensions in the halves of the split tendon. The muscle moment arm, a quantitative indicator of the action of a muscle about a joint axis, was calculated as the derivative of tendon excursion with respect to the subtalar joint angle. RESULTS The tibialis anterior had an eversion moment arm with the subtalar joint in a neutral position following surgery, but the tibialis posterior had virtually no action in the neutral position. Following the split transfers with ideally balanced tension, subtalar joint rotations of >5 degrees strongly influenced the moment arm of the tibialis posterior (p < 0.0002), indicating that its action depends on the position of the hindfoot. The moment arm of the tibialis anterior, however, was influenced only by rotations of >/=20 degrees (p > 0.1741 for each angle pair comparison of <20 degrees ). Moment arms were generally insensitive to imbalances in tension between the medial and lateral tendon halves; significant differences in the moment arm (p < 0.05), compared with that in the balanced condition, were seen only when one half was slack or nearly so. CONCLUSIONS These results suggest that it is possible for a split tendon transfer to be successful over a large range of tensionings. Split transfer of the tibialis posterior tendon produced the desired mechanical outcome in that the tibialis posterior had an eversion moment arm when the foot was inverted and an inversion moment arm when the foot was everted. Split transfer of the tibialis anterior to the cuboid, however, produced a muscle that consistently functioned as an everter regardless of the position of the hindfoot.
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