Anterior Talofibular Research Articles

Instrumented Analysis of Ankle-Subtalar Joint Complex Motion at Different Flexion Angles for Lateral Ligament Injuries

1075 PURPOSE: As part of a long-term effort (Foot Ankle, 20:12, 1999) to develop a diagnostic procedure for ankle ligament injuries, the effects of sectioning the anterior talofibular (ATFL) and calcaneofibular (CFL) ligaments on the load-displacement behavior of the ankle-subtalar joint complex were evaluated in vitro during anterior drawer and inversion rotation loading. METHODS: Eight fresh cadavers were tested using a portable instrumented arthrometer consisting of a load-measuring handle attached to a footplate and a 6-degrees-of-freedom spatial kinematic linkage connecting an anterior tibial pad to the footplate. High validity coefficients (r = .86 – .88) for ankle arthrometry have been previously reported (J Athl Train 37:4, 2002). Motion (laxity) was measured as anterior displacement (AD) (mm) at 125 N of applied force and inversion rotation (IR) (degrees ROM) at 4 N-m of applied torque at neutral and 10° dorsi- and plantar flexion. Two-way repeated-measures analysis of variance compared AD and IR before and after serial sectioning of the ATFL and CFL. RESULTS: Both flexion angle and ligament sectioning affect laxity of the ankle-subtalar joint complex. Compared to the intact ankle, sectioning the ATFL increased anterior laxity for all 3 flexion angles (neutral: 7.1 ± 2.9 vs. 9.8 ± 3.2 mm; dorsiflexion: 7.2 ± 3.4 vs. 9.7 ± 4.7 mm; plantar flexion: 7.7 ± 3.0 vs. 9.07 ± 3.2 mm; p = .001), with no differences (p >.05) between flexion angles observed. Sequentially cutting the CFL did not significantly increase (p = .137) anterior laxity compared to the ATFL condition. During inversion loading, the ankle-subtalar joint complex was most lax in plantar flexion and most stable in dorsiflexion, with the greatest laxity differences observed between neutral and dorsiflexion (p = .04). Cutting the ATFL did not significantly increase inversion laxity compared to the intact condition across the 3 flexion angles. Whereas, sectioning the CFL increased inversion laxity significantly compared to the intact ankle (neutral: 16.3 ± 4.1 vs. 23.5 ± 9.3°; dorsiflexion: 15.2 ± 4.3 vs. 21.6 ± 8.8°; plantar flexion: 17.5 ± 5.2 vs. 25.3 ± 11.9°; p = .013) and ATFL injury condition (neutral: 17.4 ± 4.8 vs. 23.5 ± 9.3°; dorsiflexion: 14.8 ± 4.5 vs. 21.6 ± 8.8°; plantar flexion: 17.8 ± 5.4 vs. 25.3 ± 11.9°; p = .021). CONCLUSIONS: Results of this study indicate that arthrometric measurements provide a basis for differentiating between the intact ankle and isolated injury of the ATFL or combined ATFL and CFL injury.

Instrumented Analysis of Ankle-Subtalar Joint Complex Motion at Different Flexion Angles for Lateral Ligament Injuries

1075 PURPOSE: As part of a long-term effort (Foot Ankle, 20:12, 1999) to develop a diagnostic procedure for ankle ligament injuries, the effects of sectioning the anterior talofibular (ATFL) and calcaneofibular (CFL) ligaments on the load-displacement behavior of the ankle-subtalar joint complex were evaluated in vitro during anterior drawer and inversion rotation loading. METHODS: Eight fresh cadavers were tested using a portable instrumented arthrometer consisting of a load-measuring handle attached to a footplate and a 6-degrees-of-freedom spatial kinematic linkage connecting an anterior tibial pad to the footplate. High validity coefficients (r = .86 – .88) for ankle arthrometry have been previously reported (J Athl Train 37:4, 2002). Motion (laxity) was measured as anterior displacement (AD) (mm) at 125 N of applied force and inversion rotation (IR) (degrees ROM) at 4 N-m of applied torque at neutral and 10° dorsi- and plantar flexion. Two-way repeated-measures analysis of variance compared AD and IR before and after serial sectioning of the ATFL and CFL. RESULTS: Both flexion angle and ligament sectioning affect laxity of the ankle-subtalar joint complex. Compared to the intact ankle, sectioning the ATFL increased anterior laxity for all 3 flexion angles (neutral: 7.1 ± 2.9 vs. 9.8 ± 3.2 mm; dorsiflexion: 7.2 ± 3.4 vs. 9.7 ± 4.7 mm; plantar flexion: 7.7 ± 3.0 vs. 9.07 ± 3.2 mm; p = .001), with no differences (p >.05) between flexion angles observed. Sequentially cutting the CFL did not significantly increase (p = .137) anterior laxity compared to the ATFL condition. During inversion loading, the ankle-subtalar joint complex was most lax in plantar flexion and most stable in dorsiflexion, with the greatest laxity differences observed between neutral and dorsiflexion (p = .04). Cutting the ATFL did not significantly increase inversion laxity compared to the intact condition across the 3 flexion angles. Whereas, sectioning the CFL increased inversion laxity significantly compared to the intact ankle (neutral: 16.3 ± 4.1 vs. 23.5 ± 9.3°; dorsiflexion: 15.2 ± 4.3 vs. 21.6 ± 8.8°; plantar flexion: 17.5 ± 5.2 vs. 25.3 ± 11.9°; p = .013) and ATFL injury condition (neutral: 17.4 ± 4.8 vs. 23.5 ± 9.3°; dorsiflexion: 14.8 ± 4.5 vs. 21.6 ± 8.8°; plantar flexion: 17.8 ± 5.4 vs. 25.3 ± 11.9°; p = .021). CONCLUSIONS: Results of this study indicate that arthrometric measurements provide a basis for differentiating between the intact ankle and isolated injury of the ATFL or combined ATFL and CFL injury.

The effect of an ankle brace on the 3-dimensional kinematics and tibio-talar contact condition for lateral ankle sprains.

Ten fresh-frozen cadaveric ankles were studied to investigate the effect of an ankle brace (Air-Stirrup) on the three-dimensional (3-D) motion and contact-pressure distribution of the talo-tibial joint with lateral ligamentous injury. Three-dimensional motion and contact-pressure distribution were simultaneously measured under dynamic conditions employing a direct linear-transformation technique and a dynamic-pressure sensor, respectively. Inversion increased significantly upon severing of the anterior talo-fibular (ATF) ligament and calcaneo-fibular (CF) ligaments; however, restoration to the intact level was observed following application of the ankle brace. Internal rotation also increased upon severing of the lateral ligaments in the plantar flexion; however, this difference was not altered by using the ankle brace. The contact area on the articular surface of the talus shifted from posterior to anterior between plantar flexion and dorsal flexion; additionally, a high pressure area was evident in the medial aspect of the talus following severing of the lateral ligaments. Upon application of the ankle brace, however, no significant changes were apparent in the contact condition. The results of this study suggest that stabilization against inversion is the major function of braces in terms of protection of ankle sprains. Ankle sprains, however, often occur in combinations of inversion, plantar flexion and internal rotation; therefore, restriction of plantar flexion and internal rotation may also be an important function of the ankle brace.

Interindividuelle Varianz unterschiedlicher Operateure bei der Festlegung der distalen Insertionsstellen der lateralen Kollateralbänder des OSG

Am lateralen Malleolus mit seiner gegenuber dem medialen Malleolus groseren Kapselflache fur die Sprunggelenke finden sich drei verstarkende Bander, deren Relationen zueinander sowie zu der Achse des subtalaren und des Sprunggelenkes bei allen rekonstruktiven Masnahmen sorgfaltige Beachtung finden mussen. Die grosen biomechanischen Relevanz dieser Ligamente fordert eine anatomische korrekte Wiederherstellung. Die Reproduzierbarkeit operativer ligamentarer Rekonstruktionen ist bislang jedoch nicht untersucht worden. An einem nach Thiel fixierten Fus-Praparat wurde lateral ein epifaszialer Aspekt hergestellt, der operativen Gegebenheiten fur eine Bandrekonstruktion entsprach. Mit Kanulen wurden Referenzpunkte festgelegt und vermessen (spharischer Exzess unter 5%). 33 operativ erfahrene Orthopaden markierten unabhangig voneinander die distalen Ansatze der Ligg. calcaneo-fibulare und talo-fibulare entsprechend ihrem operativen Vorgehen. Die photographische Dokumentation erfolgte bei 6 Pixel pro Millimeter. Nach Beendigung der Messreihe wurden die anatomischen Ansatze als Goldstandard freiprapariert. Die Kalibirierung erfolgte durch einen mitphotographierten Masstab. Die perspektivischen Verzerrungen der Einzelphotos wurden interaktiv anhand der Referenzpunkte und der anatomischen Strukturen durch Uberlagerung korrigiert. Kein Kandidat traf die tatsachlichen Ansatzpunkte entsprechend der Freipraparation. Der mittlere Abstand zwischen den Punkten lag bei ca 75% des tatsachlichen Abstandes. Der Abstand zum calcaneo-fibularen war im Mittel geringer als beim talo-fibularen Ansatz, hatte aber eine grosere Streubreite und lag in 79% zu weit cranial, d. h. wurden systematisch falsch eingeschatzt. 3 Operateure suchten den Ansatz des Lig. talo-fibulare cranial des Malleolus lateralis. 2 Kandidaten verlegten die Insertion des Lig. calcaneo-fibulare nach ventral (bezogen auf den Mallelolus lateralis). Der Winkel zwischen den Bandern wurde 29-mal zu klein eingeschatzt und 1 Kandidat erzielte einen nach dorsocranial statt nach ventrocaudal offenen Winkel. Bei 23 Operateuren wich die Winkelhalbierende um mehr als 10° von der anatomischen Richtung im Praparat ab, 17-mal davon zu sehr nach ventral. Die vorliegende Untersuchung zeigt, dass es eine grose Variabilitat zwischen unterschiedlichen Operateuren gibt. Alleine hierdurch ist mit einer grosen Streuung der klinischen Ergebnisse zu erwarten.

Visualization of ankle tendons and ligaments with MR imaging: influence of passive positioning.

To determine if passive positioning of the ankle influences the MR imaging appearance of ankle tendons and ligaments. A positioning device was used during imaging of 10 volunteers. Axial and coronal T1-weighted images were acquired in six positions of the ankle, and the appearance of the tendons and lateral ligaments was subjectively evaluated. The peroneus longus (PL), peroneus brevis (PB), anterior tibialis (AT), extensor digitorum longus (EDL), and extensor hallucis longus (EHL) tendons were best visualized in 20 degrees of plantarflexion and 20 degrees of inversion (p < 0.0001). The anterior talofibular (ATF) and calcaneofibular (CF) ligaments were best seen in 20 degrees of plantarflexion (p < 0.0001). Ten degrees of dorsiflexion was the least useful imaging plane for all of the aforementioned structures. When there is clinical concern regarding pathology of a specific structure about the ankle, passive positioning may allow optimal evaluation.

A new ankle laxity tester and its use in the measurement of the effectiveness of taping

Damage to the lateral ligaments of the ankle, namely the anterior talofibular (ATFL) and the calcaneofibular (CFL) ligaments, is a frequently reported sports injury. The anterior drawer test is generally used to evaluate whether the ATFL has been torn, while the talar tilt test is used to determine if the CFL has been injured. Although these two manual tests are often utilized for quick diagnosis, they have been criticized because of their subjective nature and their inability to produce quantitative and reproducible results. A prototype ankle tester was manufactured that could measure the input force and torque, as well as the linear and angular deprivations for the anterior drawer test and the talar tilt test, respectively. This device was used to take readings on 10 human volunteers of a mean age of 21.6 years. This device was X-ray compatible, adjustable for varying patient sizes, relatively small, portable, and easy to operate. Testing was performed to determine how the stiffness of the ankle would respond to taping, and the effect of walking on the taped ankle. The overall mean anterior drawer was 5.93 mm and the mean talar tilt was 51.6° for bare ankles using a force of 111 N (25 lbs) for the drawer and a torque of 16 N m for the tilt. Taping provided an average increase in stiffness of 11.3%, demonstrating that it did provide increased stability. However, statistically significant ( P<0.05) decreases in the stiffness subsequent to taping were observed between the initially taped ankles and after 20 min of walking, when it was shown that talar tilt had increased. The prototype ankle tester produced repeatable measurements, and results show that the increase in stiffness due to taping did decrease after a short period of time.

Ankle biomechanics during impact landings on uneven surfaces.

Inversion sprains of the lateral ligaments of the ankle are one of the most common of all sporting injuries. While the strains in the anterior talofibular (ATFL) and calcaneofibular (CFL) ligaments have been measured in quasi-static conditions, the dynamic strains during an actual traumatic event have not been determined. The present investigation determined the strains and strain rates in the ATFL and CFL during an in vitro inversion sprain. The ATFL tended to have higher strain and strain rate values than the CFL, which may explain why it is more often injured than the CFL.

Linear and quasi-linear viscoelastic characterization of ankle ligaments.

The objective of this study was to produce linear and nonlinear viscoelastic models of eight major ligaments in the human ankle/foot complex for use in computer models of the lower extremity. The ligaments included in this study were the anterior talofibular (ATaF), anterior tibiofibular (ATiF), anterior tibiotalar (ATT), calcaneofibular (CF), posterior talofibular (PTaF), posterior tibiofibular (PTiF), posterior tibiotalar (PTT), and tibiocalcaneal (TiC) ligaments. Step relaxation and ramp tests were performed. Back-extrapolation was used to correct for vibration effects and the error introduced by the finite rise time in step relaxation tests. Ligament behavior was found to be nonlinear viscoelastic, but could be adequately modeled up to 15 percent strain using Fung's quasilinear viscoelastic (QLV) model. Failure properties and the effects of preconditioning were also examined.

Trabecular trauma of the talus and medial malleolus concurrent with lateral collateral ligamentous injuries of the ankle: evaluation with MR imaging.

The objective of this study was to elucidate the relationship between lateral collateral ligamentous injuries of the ankle (ankle sprain) and bone bruise (trabecular trauma) of the talus and/or malleoli in the patients with twisting injuries of the ankle. Magnetic resonance studies of the ankle were retrospectively reviewed, focusing on the presence or absence of lateral collateral ligamentous injuries and the location of bone bruise in the talus and/or malleoli. Thirty-five patients with acute twisting injuries of the ankle were studied. Four patterns of bone bruise were found in 14 patients: (1) bone bruise in the talar dome equivalent to osteochondral fracture in two patients, (2) bone bruise in the posteromedial aspect of the talus and the medial malleolus singly or in combination in four, (3) bone bruise in the anteromedial aspect of the talus in six, and (4) bone bruise with a combination of the second and third patterns in two. The second pattern was associated with tear of the anterior talofibular (ATAF) ligament in all patients and injury of the calcaneofibular (CF) ligament in one out of four. The third and fourth patterns were associated with tears of both ATAF and CF ligaments in all patients. The identification of bone bruise was of value in indicating lateral collateral ligamentous injuries.

Ankle Instability: In Vitro Kinematics in Response to Axial Load

This study was undertaken to elucidate the kinematics of hindfoot instability. An axial load was applied to the inverted hindfoot. Unlike prior studies, axial rotation was not constrained. Using computerized tomography, measurements were made on the axial views of external or internal rotation of the leg, talus, and calcaneus. On the coronal views, tilting of the talus at the ankle and subtalar joints was assessed. No tilting of the talus in the mortise occurred with isolated release of the anterior talofibular (ATF) or calcaneofibular (CF) ligament. In every specimen, talar tilt occurred only after both ligaments were released, averaging 20.6 degrees. External rotation of the leg occurred with inversion averaging 11.1 degrees in the intact specimen. The leg averaged a further external rotation of 4.9 degrees after ATF release and 12.8 degrees further than the intact inverted specimens when both ligaments (ATF-CF) had been released. In earlier reports on the subject, the articular surfaces were believed to be the main constraint against tilting of the talus. In those studies, either axial rotation was constrained while inversion was allowed, or vice versa. Based on the data reported here, the ATF and the CF work in tandem to prevent tilting of the talus, and the articular surfaces do not seem to prevent tilting of the talus in the mortise.

Stress Examination of Traumatized Lateral Ligaments of the Ankle

In the diagnostic analysis of acute injury to the lateral ankle ligaments, ankle arthrography and plain film stress examination play an important role. Inasmuch as the treatment of choice, whether conservative or surgery, and insofar as the therapeutic results may be determined by the extent of injury, it is important to have access to quantitative information on the functional properties of the involved ligaments at the time of the initial diagnostic studies. This can be obtained by measuring the strain on the anterior talofibular (tf) and calcaneofibular (cf) ligaments as a function of pressure applied to the distal tibia. Any device that ensures that the externally applied pressure is proportionally carried through to the ligaments can be used for this purpose. The results of 25 quantitative stress examinations using a Telos stress device are compared with arthrography findings and findings at surgery. Stress examination correlates well with both arthrographic and operative findings. The method is also useful for the evaluation of chronic ankle instability, follow-up examinations, and for the detection of vestiges of previous trauma of the contralateral ankle. The procedure is straightforward and noninvasive and can be performed within 15 minutes.

足関節外側側副じん帯損傷のストレスＸ線評価について 問題点に対する実験的考察

In order to clarify roentgenographical diagnosis of ankle instability resulting from lateral ligament injury of the ankle, morphological measurements of the anterior talofibular(ATF) ligament and the calcaneofibular (CF) ligament were performed utilizing thirty-three cadaver ankles and six amputated ankles. The ATF ligaments of sixteen ankles were cut and changes in ankle instability which were influenced by the application of force and the position of the ankle were observed. Then the CF ligament was also cut and changes in ankle instability were again noted.In taking stress roentgenograms of the anterior drawer test and the varus stress test, it may be desirable to keep the ankle in a neutral position and apply manually a force of more than 10kg.In the above mentioned situation, it is suggested that the anterior drawer test is mainly related to the condition of the ATF ligament and the varus stress test to that of the CF ligament.