Talar Tilt Test Research Articles

Biomechanical Comparison of an Open vs Arthroscopic Approach for Lateral Ankle Instability.

The current clinical standard for the surgical treatment of ankle instability remains the open modified Broström procedure. Modern advents in arthroscopic technology have allowed physicians to perform certain foot and ankle procedures arthroscopically as opposed to traditional open approaches. Twenty matched lower extremity cadaver specimens were obtained. Steinman pins were inserted into the tibia and talus with 6 sensors affixed to each pin. Specimens were placed in a Telos ankle stress apparatus in an anteroposterior and then lateral position, while a 1.7 N-m load was applied. For each of these tests, movement of the sensors was measured in 3 planes using the Optotrak Computer Navigation System. Changes in position were calculated and compared with the unloaded state. The anteriortalofibular ligament and the calcaneofibular ligament were thereafter sectioned from the fibula. The aforementioned measurements in the loaded and unloaded states were repeated on the specimens. The sectioned ligaments were then repaired using 2 corkscrew anchors. Ten specimens were repaired using a standard open Broström-type repair, while the matched pairs were repaired using an arthroscopic technique. Measurements were repeated and compared using a paired t test. There was a statistically significant difference between the sectioned state and the other 3 states (P < .05). There were no statistically significant differences between the intact state and either the open or arthroscopic state (P > .05). There were no significant differences between the open and arthroscopic repairs with respect to translation and total combined motion during the talar tilt test (P > .05). Statistically significant differences were demonstrated between the 2 methods in 3 specific axes of movement during talar tilt (P = .04). Biomechanically effective ankle stabilization may be amenable to a minimally invasive approach. A minimally invasive, arthroscopic approach can be considered for treating patients with lateral ankle instability who have failed conservative treatment.

Narrowing the Normal Range for Lateral Ankle Ligament Stability with Stress Radiography

Stress radiographs are commonly performed to evaluate lateral ankle ligament stability; however, little agreement exists on the physiologic limits obtained from the anterior drawer and talar tilt stress tests. Published studies have reported the normal range for the anterior drawer test to be 3 to 10 mm and the normal range for the talar tilt test to be 0° to 23° for the uninjured ankle, leading to inconsistent interpretation. The primary objective of the present study was to narrow the threshold for the diagnosis of ankle ligament injury using stress radiographs by refining the values seen in the normal ankle. An improved understanding of normal ankle motion could allow for a more accurate determination of ligament injury using stress imaging. Conducted in a simplified, yet reproducible, manner, we hoped the present study would draw a parallel with generalized use in an office setting and would allow physicians the ability to more effectively diagnose ankle ligament injury. Bilateral radiographic images of anterior drawer and talar tilt stress tests were taken of 50 participants (100 ankles) with no history of ankle fracture or surgical intervention for ankle instability. Participants with a previous ankle sprain were later excluded from the result computations. Factors such as patient age and gender were evaluated. In the final analysis, 46 participants (76 ankles) were included, with a mean anterior drawer test result of 2.00 mm ± 1.71 mm and talar tilt test result of 3.39° ± 2.70° in the normal ankle. The results of the present study suggest that stress radiographs for lateral ankle stability can be performed in a simple and reliable manner. These results also support a much lower threshold for the diagnosis of lateral ankle injury than previously reported.

Lateral ligament reconstruction with allograft in patients with severe chronic ankle instability

Chronic ankle instability is a condition of perception of giving way and persistent pain usually following multiple ankle sprains. In case of severe joint laxity, surgical treatment with reconstruction of the lateral ligamental complex is recommended. The aim of this study was to evaluate the functional outcome of patients treated with lateral ligament reconstruction with allograft for severe chronic lateral ankle instability. We performed a retrospective cohort study of ten patients who underwent allograft external non-anatomic ligamentoplasty for severe chronic lateral ankle instability between 2009 and 2011, with an average follow-up of 16.3 months (SD 8.2). Median age at surgery was 29 years (range 25-35). All patients presented both ATFL and CFL lesion. Patients were evaluated using American Orthopaedic Foot and Ankle Society score, Karlsson-Peterson score, Tegner activity level, Sefton stability scale, and objective examination comprehending range of motion, anterior drawer sign and talar tilt test. Telos stress equipment was used for pre- and post-operative radiographic laxity testing. Follow-up examination at an average of 16.3 months (SD 8.2) after surgery showed significant improvement of all variables compared to pre-operative values (p < 0.001). Most patients rated their outcome as good/excellent. Telos stress radiographs documented improvement in joint stability. Lateral ligament reconstruction with allograft represents a valid treatment option in patients with severe chronic lateral ankle instability.

The prevalence of clinical signs of ankle instability in club rugby players

Background. Ankle injuries are one of the most common injuries in sport and have a high recurrence rate.Aim. To determine the prevalence of clinical signs of ankle injuries in club rugby players in South Gauteng.Methods. Institutional ethical clearance was obtained for the study. Of the 180 players from 9 clubs who were eligible for participation in thestudy, 76% (n=137) were recuited. Informed consent was obtained before players were asked to complete a battery of tests. Each player wasasked to complete a demographic questionnaire and the Olerud and Molander questionnaire to determine the prevalence of clinical signs ofperceived instability. The prevalence of clinical signs of mechanical instability was determined by the anterior drawer test (ADT) and talartilt test (TTT). Balance and proprioception were assessed by the Balance Error Scoring System (BESS) and this was used to determine theprevalence of clinical signs of functional instability.Results. The prevalence of perceived instability was 44%. The prevalence of clinical signs of mechanical ankle instability was 33%. There was anincreased prevalence of mechanical instability in players who had a history of previous ankle injuries: ADT left (p=0.003); ADT right (p=0.01);TTT left (p=0.001); TTT right (p=0.08), both tests positive left (p=0.001) and both tests positive right (p=0.03). The prevalence of clinical signsof functional ankle instability depended on the surface and visual input, and was greater as the challenge or perturbation increased.Conclusion. There was a high prevalence of clinical signs of ankle instability in club rugby players for perceived, mechanical and functionalinstability. Those with previously injured ankles were more likely to have unstable ankles.

The prevalence of clinical signs of ankle instability in club rugby players

Background . Ankle injuries are one of the most common injuries in sport and have a high recurrence rate. Aim . To determine the prevalence of clinical signs of ankle injuries in club rugby players in South Gauteng. Methods . Institutional ethical clearance was obtained for the study. Of the 180 players from 9 clubs who were eligible for participation in the study, 76% (n=137) were recuited. Informed consent was obtained before players were asked to complete a battery of tests. Each player was asked to complete a demographic questionnaire and the Olerud and Molander questionnaire to determine the prevalence of clinical signs of perceived instability. The prevalence of clinical signs of mechanical instability was determined by the anterior drawer test (ADT) and talar tilt test (TTT). Balance and proprioception were assessed by the Balance Error Scoring System (BESS) and this was used to determine the prevalence of clinical signs of functional instability. Results . The prevalence of perceived instability was 44%. The prevalence of clinical signs of mechanical ankle instability was 33%. There was an increased prevalence of mechanical instability in players who had a history of previous ankle injuries: ADT left (p=0.003); ADT right (p=0.01); TTT left (p=0.001); TTT right (p=0.08), both tests positive left (p=0.001) and both tests positive right (p=0.03). The prevalence of clinical signs of functional ankle instability depended on the surface and visual input, and was greater as the challenge or perturbation increased. Conclusion . There was a high prevalence of clinical signs of ankle instability in club rugby players for perceived, mechanical and functional instability. Those with previously injured ankles were more likely to have unstable ankles.

The prevalence of clinical signs of ankle instability in club rugby players

Background. Ankle injuries are one of the most common injuries in sport and have a high recurrence rate.Aim. To determine the prevalence of clinical signs of ankle injuries in club rugby players in South Gauteng.Methods. Institutional ethical clearance was obtained for the study. Of the 180 players from 9 clubs who were eligible for participation in thestudy, 76% (n=137) were recuited. Informed consent was obtained before players were asked to complete a battery of tests. Each player wasasked to complete a demographic questionnaire and the Olerud and Molander questionnaire to determine the prevalence of clinical signs ofperceived instability. The prevalence of clinical signs of mechanical instability was determined by the anterior drawer test (ADT) and talartilt test (TTT). Balance and proprioception were assessed by the Balance Error Scoring System (BESS) and this was used to determine theprevalence of clinical signs of functional instability.Results. The prevalence of perceived instability was 44%. The prevalence of clinical signs of mechanical ankle instability was 33%. There was anincreased prevalence of mechanical instability in players who had a history of previous ankle injuries: ADT left (p=0.003); ADT right (p=0.01);TTT left (p=0.001); TTT right (p=0.08), both tests positive left (p=0.001) and both tests positive right (p=0.03). The prevalence of clinical signsof functional ankle instability depended on the surface and visual input, and was greater as the challenge or perturbation increased.Conclusion. There was a high prevalence of clinical signs of ankle instability in club rugby players for perceived, mechanical and functionalinstability. Those with previously injured ankles were more likely to have unstable ankles.

Biomechanical Analysis of Brostrom Versus Brostrom-Gould Lateral Ankle Instability Repairs

The traditional Brostrom repair and the modified Brostrom-Gould repair are 2 historically reliable procedures used to address lateral ankle instability. The purpose of this study was to evaluate the biomechanical stability conferred by the Brostrom repair as compared to the Brostrom-Gould modification in an unstable cadaveric ankle model. A total of 10 cadaveric specimens were placed in a Telos ankle stress apparatus in an anterior-posterior position and then in a lateral position, while a 170 N load was applied to simulate anterior drawer (AD) and talar tilt (TT) tests, respectively. In both circumstances, the ankle was held in 15 degrees of plantarflexion, neutral, and 15 degrees of dorsiflexion, while the movement of the sensors was measured using a video motion analysis system. Measurement of the translation between the talus and tibia in the AD test and the angle between the tibia and talus in the TT test were calculated for specimens in the (1) intact, (2) sectioned (division of the ATFL and CFL), (3) Brostrom repair and (4) Gould modification states. When compared to both the repaired states and the intact states, the sectioned state demonstrated increased inversion and translation at all ankle positions during TT and AD testing. Furthermore, no significant differences were found between the intact state and either of the repaired states. Finally, no difference in the biomechanical stability could be identified between the traditional Brostrom repair and the modified Brostrom-Gould procedure. Our findings indicate that there is no significant biomechanical difference in initial ankle stability conferred by augmenting the traditional Brostrom repair with the Gould modification in this time-zero cadaveric model. These data suggest that the additional reinforcement of an ankle's lateral ligament complex repair of the ankle with the inferior extensor retinaculum may be marginal at the time of surgery.

Utilizzo di “allograft” per il trattamento dell’instabilità cronica di caviglia

Ten patients who underwent allograft external ligamentoplasty for chronic lateral ankle instability between 2009 and 2011, were retrospectively evaluated with an average follow-up of 16.3 months (SD: 8.2). Median age at surgery was 29 years (range: 25 to 35). All patients presented both anterior talo-fibular (ATFL) and calcaneo-fibular (CFL) ligaments lesion. Patients were evaluated using AOFAS score, Karlsson-Peterson score, Tegner activity level, Sefton stability scale, and objective examination comprehending ROM, anterior drawer sign and talar tilt test. Telos Stress equipment was used for pre- and post-operative radiographic laxity testing. Follow-up examination at an average of 16.3 months after surgery showed significant improvement of all variables compared to pre-operative values (p<0.001). Allograft ligamentoplasty represents a valuable treatment option in patients with severe chronic lateral ankle instability.

Accuracy of Plain Radiographs Versus 3D Analysis of Ankle Stress Test

Radiographic stress testing using both the anterior drawer (AD) and talar tilt (TT) technique is a widely accepted means of assessing ankle instability. The purpose of this study was to investigate the accuracy of plain film radiography in measuring translation of the talus during the AD test and the rotation of the talus during TT stress testing. In addition to determining the true accuracy of radiologic assessment in two planes, our goal was to further define instability in the sagittal, coronal and transverse planes. Twenty lower extremity specimens were placed in a Telos ankle stress apparatus, and respective lateral and AP radiographs were taken during simulated AD and TT testing. Positional measurements were calculated from the films. Next, a three-dimensional tracking system was used to calculate these displacements. The anterior talofibular ligament and calcaneofibular ligament were sectioned to simulate an unstable ankle, followed by repeat measurement using both methods. Movement calculated using the three dimensional system was compared to that of plain radiographs using a paired t-test. Mean positional changes determined by plain film radiographs were found to be significantly lower than those calculated by the three-dimensional system in both AD and TT tests in the intact and sectioned states (p < 0.001). Radiographic stress testing assessment of ankle instability appears to be much less accurate than previously believed. Compared to values calculated with the 3D system, radiographic measurements may underestimate the true magnitude of TT and AD changes which could influence clinical decision making.

Hip Kinematics During a Stop-Jump Task in Patients With Chronic Ankle Instability

Chronic ankle instability (CAI) commonly develops after lateral ankle sprain. Movement pattern differences at proximal joints may play a role in instability. To determine whether people with mechanical ankle instability (MAI) or functional ankle instability (FAI) exhibited different hip kinematics and kinetics during a stop-jump task compared with "copers." Cross-sectional study. Sports medicine research laboratory. Sixty-three recreational athletes, 21 (11 men, 10 women) per group, matched for sex, age, height, mass, and limb dominance. All participants reported a history of a moderate to severe ankle sprain. The participants with MAI and FAI reported 2 or more episodes of giving way at the ankle in the last year and decreased functional ability; copers did not. The MAI group demonstrated clinically positive anterior drawer and talar tilt tests, whereas the FAI group and copers did not. Participants performed a maximum-speed approach run and a 2-legged stop jump followed by a maximum vertical jump. An electromagnetic tracking device synchronized with a force plate collected data during the stance phase of a 2-legged stop jump. Hip motion was measured from initial contact to takeoff into the vertical jump. Group differences in hip kinematics and kinetics were assessed. The MAI group demonstrated greater hip flexion at initial contact and at maximum (P = .029 and P = .017, respectively) and greater hip external rotation at maximum (P = .035) than the coper group. The MAI group also demonstrated greater hip flexion displacement than both the FAI (P = .050) and coper groups (P = .006). No differences were noted between the FAI and coper groups in hip kinematic variables or among any of the groups in ground reaction force variables. The MAI group demonstrated different hip kinematics than the FAI and coper groups. Proximal joint motion may be affected by ankle joint function and laxity, and clinicians may need to assess proximal joints after repeated ankle sprains.

A Biomechanical Comparison of an Open vs. Arthroscopic Approach for the Treatment of Lateral Ankle Instability (SS-57)

Introduction Ankle sprains are the most common musculoskeletal injury, accounting for 2 million emergency department visits annually. Most sprains involve the lateral ligament complex secondary to an inversion force on a plantar flexed foot. The diagnosis of chronic ankle instability is considered when repetitive sprains or persistent symptoms of giving way are present. The current clinical standard is the open modified Brostrom procedure (open). Many surgeries in orthopedics have evolved with minimally invasive approaches. The purpose of this study was to biomechanically compare a minimally invasive arthroscopic technique for the treatment of ankle instability to the open technique. Methods Twenty matched lower extremity cadaver specimens were tested (mean 40 ± 12 years). Specimens were examined for gross instability or anatomic lesions. Steinman pin wires were inserted into the tibia and the talus, and six sensors were rigidly affixed to each of the wires to establish relative planes of movement. Specimens were placed in a Telos ankle stress apparatus and loaded to 1.7 N-m in two orientations simulating the anterior drawer and talar tilt clinical exam tests. For each of these tests the ankle was held in three orientations: 15° plantar-flexion, neutral alignment, and 15° dorsiflexion. During testing, the movement of the sensors was measured in three separate planes using the Optotrak Computer Navigation System. The difference in translation between the talus and the tibia in the loaded anterior drawer test and the angle between the tibia and talus in the loaded talar tilt test were calculated and compared to the unloaded state to determine the differences in translation and angle. Following intact testing, the anterior talofibular ligament and the calcaneofibular ligament were both sectioned from the fibula to simulate an unstable ankle and retested in all test modes. Sectioned ligaments were then repaired using two 3.5mm diameter corkscrew suture anchors. One anchor was placed at the ATFL origin and the other at the CFL origin. Ten of the specimens were repaired using the standard open repair; while the remaining 10 contralateral specimens were repaired using an arthroscopic technique. All test modes were retested following repair. Statistically significant differences in displacement within treatment groups were analyzed using a repeated measures ANOVA. A paired t-test was used to determine differences between the open and arthroscopy groups. Results There was significantly more motion in the sectioned ankles compared to intact and both treated groups for all but one test mode (anterior drawer in dorsiflexion, p=0.054). The arthroscopic and open repair techniques were biomechanically similar with the exception of the inversion in plantar flexion. However, the difference in total combined motion was not statistically significant and both repair groups were statistically superior to the sectioned state. Conclusion Our findings suggest similar improvement in biomechanical function with both the arthroscopic and open repairs when compared to the sectioned state. Both techniques were shown to be comparable to the intact state suggesting that biomechanically effective ankle stabilizations may be able to be performed through a minimally invasive approach.

Treatment of lateral ankle ligament injuries and ankle instability with semitendinosus tendon graft

Objective To explore the effectiveness of ipsilateral autologous semitendinosus ten don graft in treatment of lateral ankle ligament injuries and ankle instability. Methods Two patients including one male (25 years old) and one female (17 years old) with chronic lateral instability of the ankle were enrolled in the study. Both patients had the history of repeated ankle sprain in supination position and had grade Ⅲ injury of the lateral ankle ligament according to the American College of Foot and Ankle Surgeons Grading System. Anterior drawer test and talar tilt test were all positive. The stress-inversion radiograph demonstrated the average inclination of the talus for 21 ° and the lateral radiograph demonstrated anterior dislocation of the talus. The chronic ankle instabilities in two patients were treated by using the ipsilateral autologous semitendinosus tendon graft to reconstruct the lateral ankle ligament. Results The two patients were followed up for mean eight months, which revealed that the active and passive range of motion was good, with no pain or swelling. The anterior drawer test and talar tilt test were all negative. The stress-inversion radiograph demonstrated that the average inclination of the talus was less than 5°, with no anterior dislocation of the talus. According to the Mazur grading system, the clinical outcome was excellent in one patient and good in one. The two patients were satisfied with the stability of the ankle. Conclusions ( 1 ) Lateral ankle ligament injury is a common cause of chronic ankle instability,even the ankle osteoarthritis. ( 2 ) Brostr(o)m method can attain satisfactory result for fresh lateral injury of the ankle, but not for the old injuries. ( 3 ) Ipsilateral autologous semitendinosus tendon graft is simpleand effective for treatment of lateral ankle ligament injuries and chronic ankle instability and may play an important role in the treatment of lateral ankle instability and prevention of the occurrence of ankle osteoarthritis. Key words: Ankle joint; Sprains and strains; Lateral ligament,ankle

Reliability of the Anterior Drawer and Talar Tilt Tests Using the Ligmaster Joint Arthrometer

Joint arthrometers have been developed to help determine the severity of ligament sprains. To establish intratester and intertester reliability of the talar inversion and anterior drawer tests using the LigMaster. Intratester reliability was investigated using a repeated-measures design. Intertester reliability was investigated using 2 different clinicians testing subjects on the same day. Athletic training research laboratory. Thirty participants volunteered for this study. Anterior displacement and talar inversion were measured using the LigMaster. Intrarater reliability was .74 for the talar inversion test and .65 for the anterior drawer test. Interrater reliabilities for the talar inversion and anterior drawer tests were .76 and .81, respectively. The LigMaster joint arthrometer is a reliable tool for measuring talar inversion and anterior displacement at the ankle.

Chronic Ankle Instability Influences Laxity and Stiffness during Anterior Drawer But Not Inversion Talar Tilt

PURPOSE: To assess ankle laxity and stiffness during the anterior drawer and talar tilt tests with an instrumented arthrometer in individuals with and without chronic ankle instability (CAI). METHODS: Twenty-seven subjects with CAI (20 females, 7 males) and 20 healthy control subjects (14 females, 6 males) participated. The CAI subjects had an average of 5.5 +/− 3.7 previous ankle sprains, and scores of 89.0 +/− 7.5 percent and 74.9 +/− 14.0 percent on the Foot and Ankle Disability Index Main and Sport scales, respectively. An ankle arthrometer was used to perform an anterior drawer test to a load of 125 N and an inversion talar tilt test to 4000 N-mm. For both tests, laxity was quantified as the amount of maximal displacement and stiffness was estimated by calculating the slope of the force displacement curve. RESULTS: The CAI group had significantly greater anterior drawer laxity on their involved ankles (11.1 +/− 4.3 mm) than the control group had on their side-matched ankles (7.6 +/− 3.8 mm) (p=.006). The CAI group (14.3 +/− 10.3) also demonstrated significantly less stiffness during the anterior drawer test than the control group (18.4 +/− 8.9 mm) on the involved ankles (p=.028). There were no significant differences between the anterior drawer measures on the uninvolved ankles in the CAI group and the side-matched limbs in the control group. For the inversion talar tilt measures, there were no significant differences in laxity or stiffness between groups on either the involved or uninvolved ankles. CONCLUSIONS: Laxity and stiffness deficits were found in the CAI group with the anterior drawer test, but not the inversion talar tilt test. These results indicate residual mechanical insufficiency of the anterior talofibular ligament, but not the calcaneofibular ligament, in those with CAI. Mechanical deficiency of the anterior talofibular ligament alone, without concurrent involvement of the calcaneofibular ligament, may be sufficient to contribute to the development of CAI.

SECONDARY GAIT CHANGES IN SUBJECTS WITH RECURRENT ANKLE SPRAIN -SUBTALAR AND KNEE JOINT MOMENTS DURING STANCE-

This study assessed how the frontal plane moment and angle at the subtalar joint was associated with the knee joint varus moment during stance in persons with an unstable lateral ankle. METHODS Forty two female athletes (20 persons with an unstable lateral ankle: 21.4±2.4 yrs, 1.58±0.06 m, 50.6±5.4 kg and 22 healthy controls: 22.5 ±3.3 yrs, 1.61±0.05 m, 53.4±7.4 kg) participated in this experiment. Subjects were recruited by the investigator with the assistance of intramural athletic trainers. The inclusion criteria for persons with an unstable lateral ankle were: a history of at least two lateral ankle sprains to the same ankle during the past 2 years, a history of ankle pain or swelling during injury, and apprehension during either anterior drawer or talar tilt tests. Three-dimensional gait analyses were conducted with a motion analysis system (VICON) operating at 60 Hz with 12 infrared cameras and 8 force platforms (KISTLER) operating at 60 Hz. Subjects were asked to walk barefoot at a self-selected walking cadence (115.1±5.3 steps/min for persons with an unstable lateral ankle, 114.7±8.4 steps/min for healthy controls, P=0.861), indicated by a metronome. Moments were derived using a three-dimensional inverse dynamics model of the lower extremity [3]. The average moments at the subtalar and knee joints were equivalent to the division of the area under the moment-time curve and its time of application, respectively. Evaluations of the average angles and ground reaction forces were performed using the same methods as for those applied for the average moments [3]. Unpaired Student’s t-test was used to determine the statistical significance between the persons with an unstable lateral ankle and the healthy controls. In addition, simple regression analysis with Pearson coefficients was used to determine correlation between the subtalar joint valgus moment and the knee joint varus moment during stance. Table 1. Stance phase average values between healthy controls and persons with

The Effects of Exercise on Non-Accident Related Chronic Ankle Instablitiy in Participants With Collagen Disorders

Chronic functional instability is the inability of an individual to perform routine daily activities, such as standing, walking, or rising from a chair, due to the instability of joint structures. Several genetic and neuromuscular disorders exist that result in severe ankle instability (hypermobility) without a prior history of traumatic injuries (Ehlers-Danlos Syndrome, Marfan's Syndrome, Osteogenesis Imperfecta, and Benign Hypermobility Syndrome). Individuals with hypermobility are susceptible to recurring injury and have been previously treated with extensive rest, a treatment that has been shown to increase chronic instability. PURPOSE: To determine the effects of exercise and movement on non-accident-related chronic ankle instability, particularly in participants who have Ehlers-Danlos Syndrome or Benign Hypermobility Syndrome. METHODS: Five female participants (32±12 yrs) were recruited for this study and all completed the full study; three of the participants had Benign Hypermobility Syndrome and two had Ehlers-Danlos Syndrome. Participants took part in an eight-week exercise regimen, with ankle stability measurements taken at the pre-, 4-weeks, and post-study. The exercise regimen included four sections: resistance training, reactive neuromuscular training, proprioception exercises, and active stabilization exercises. Participants underwent two days of resistance training with reactive neuromuscular training and proprioception exercises, and a third day of resistance training with active stabilization exercises each week. Range of motion (using a goniometer) of the ankle was tested, and functional strength assessment included single-weight-bearing tests for dorsiflexion, plantar flexion, inversion, and eversion. Stability tests included anterior draw, posterior draw, talar tilt, wedge, and Thompson, and Kleiger's tests. RESULTS: Functional strength was increased for the five subjects, and pain levels were reduced in every subject, for each of the tests. Not only were pain levels reduced, but also joint popping was reduced and participants reported feeling higher levels of stability and balance. Subjects showed a generally reduced range of motion, from 25% to 65%, in all areas of the ankle joint. This overall decrease in the range of movement indicates a tightening of the joint capsule and an increase in joint stability. CONCLUSION: Strength exercises lead to decreased range of motion, strengthening of the ankle, increased balance, decreased pain, and an overall increase in daily function.

BIOMECHANICS OF THE INTACT AND REPLACED HUMAN ANKLE JOINT

The main objective of the study was to develop advanced biomechanical models of the intact human ankle complex. It was also aimed at designing a total ankle replacement which would better reproduce the physiological function of the joint. Passive flexion was analyzed in a number of lower-leg preparations with stereophotogrammetry and radiostereometry. The articular surfaces and fibres within the calcaneofibular and tibiocalcaneal ligaments were observed to prescribe the changing positions of bones, ligaments and instantaneous axis of rotation. Joint motion included rolling as well as sliding. Computer-based models elucidated this kinematics at the intact joint, and how changing positions of the centre of rotation and muscle lines of action affect lever arm length at different flexion angles. The mechanical response of the joint to anterior drawer and talar tilt tests was explained in terms of fibre recruitment. The experimental evidence and the geometrical models gave the basis for the design of a novel ankle replacement. A three-component, convex-tibia prosthesis was developed with articular surface shapes that are compatible with the geometry of the ligaments. The proposed prosthesis based on ligament/shape compatibility is showing encouraging results in initial implantation.

Anatomical and possible clinical relationships between the calcaneofibular ligament and peroneus brevis – a pilot study

The authors have observed in their clinical practice patients presenting with chronic retromalleolar pain following lateral ankle injuries. It has been hypothesized that persistent retromalleolar pain following a supination sprain may be due to peroneus brevis (PB) tendon tears (Boruta et al. 1990). The aims of this study were to investigate whether an anatomical relationship exists between the calcaneofibular ligament (CFL) and PB, and if so, the significance of this relationship in the positions of supination sprain and talar tilt test. Seven out of eight cadaveric ankles demonstrated fibrous connecting tissue between the tendon of PB and CFL. Four of the eight ankles demonstrated PB tendon abnormalities. The presence of connecting tissue between CFL and PB suggests an anatomical basis for concomitant damage to the PB tendon with a supination sprain, thus supporting the hypothesis that there may be an anatomical basis for persistent retromalleolar pain subsequent to injury to the lateral ankle complex.

SURFACE EMG ANALYSIS A DURING VERTICAL JUMP WHILE A SEMI-RIGID ANKLE BRACE

PURPOSE The purpose of this study was to evaluate muscle activity while wearing a semi-rigid ankle brace during a vertical jump in persons with functional ankle instability. METHODS Twelve subjects (6 stable ankles 22.0 ± 0.37 yrs; BMI = 25.1 ± 1.20 kg m2; 6 unstable ankles 22.0 ± 1.20 yrs; BMI = 28.1 ± 1.98 kg m2) volunteered to participate in the study. Ankle instability was determined by subject history as well as talar tilt and anterior drawer tests. Both stable (controls) and unstable ankle (US) subjects were asked to perform three vertical jump trials on two successive days. US group were randomly assigned into braced (B) and unbraced (UB) conditions for each day. The brace worn for the US group was a semi-rigid brace (Sure Step® Custom). Surface electromyography (SEMG) activity of seven muscles-semitendinosus, biceps femoris, vastus lateralis, vastus oblique, peroneus longus, tibialis anterior, and lateral gastrocnemius were simultaneously recorded during the jump. For each jump, the SEMG data were divided and normalized to each respective maximal voluntary isometric muscle contraction, and then averaged for all subjects across the three trials in each condition. RESULTS The controls were able to jump higher than UB subjects (F = 7.99, p < 0.05), however, there were no differences in jump height when the subjects were braced. There were also no significant differences in SEMG activity in any of the seven muscles between B and UB conditions. CONCLUSION The UB subjects were not able to jump as high as the controls, however, when braced there were no differences between groups. In addition, it appears that the brace does not limit or alter muscle activity in either the PREP or LAND phases of the vertical jump.

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.