Eccentric muscle strength in functional ankle instability

PURPOSE: To investigate muscle strength in subjects with unilateral functional ankle instability, with the specific aim of determining whether eccentric strength deficits exist. METHODS: Isokinetic invertor and evertor torques were assessed eccentrically and concentrically at speeds of 60 and 120 degrees.s(-1) in 16 subjects with unilateral ankle instability. Absolute peak torque values were compared between the injured and noninjured limbs to determine whether strength deficits existed. RESULTS: No eccentric or concentric evertor strength deficit was found in the injured limb. Interestingly, for the injured limb, a significant interaction effect was found whereby eccentric inversion strength was reduced. CONCLUSION: Functional ankle instability is not associated with deficits in evertor strength. Deficits in eccentric invertor strength were found, and this may contribute to the symptoms of functional ankle instability. Weak invertors may contribute to functional ankle instability because of a reduced ability to assist in controlling lateral displacement of the shank over the weight-bearing foot. Excess lateral postural sway outside of the base of support results in the foot's medial border rising from the floor once the limits of closed chain eversion is reached, which may result in the foot being forced into rapid inversion.     

足踝部反复损伤青少年足球运动员FootScan足底压力分析

目的:探讨足底压力分析在青少年运动损伤领域的应用价值。方法:2008年1月～2009年10月期间,在上海市普陀区青少年运动训练基地将40名16～19岁足踝部损伤3次以上的青少年足球运动员分为左足损伤和右足损伤两组,采用美国Tekscan公司的F-Scan三维动态足底压力步态分析系统,进行静、动态足底压力测试,测试数据与前期120名足踝部未损伤的健康青少年足球运动员正常数据进行对比分析。所有受试者均脱鞋袜,以个人正常步态自然行走,测量双脚各3次静、动态足底压力,测量指标为足底每个区域的压强峰值、接触时间负荷,计算足底各区域的压强峰值和负荷分布、重心轨迹特征。结果:青少年足球运动员损伤侧足底压力分布特征:(1)足底压强峰值最大区域在第5跖骨、足跟外侧;(2)足前区跖骨部的内侧与外侧比值低于正常参考值,差异具有统计学意义,足前区存在内翻倾向;(3)足部压力重心变化有向足前区转移的趋势,双足压强变化不对称;(4)足踝反复损伤者前足撑地时间延长,后足撑地时间减少。结论:足踝反复损伤青少年足球运动员足底压强变化不稳定,双足压强变化不对称;损伤足与正常对照差异显著,足部压力重心变化有向足前区转移的趋势,前足撑地时间延长,后足撑地时间减少,可能是为了减少损伤侧足踝关节的载荷而采取的保护性机制。足底压力分析在预防青少年足球运动员足踝反复损伤方面有临床价值。     

Directions of single-leg landing affect multi-segment foot kinematics and dynamic postural stability in male collegiate soccer athletes

BackgroundUnderstanding lower limb kinematics and postural control in different directions of single-leg landings is critical to evaluate postural control and prevent lower limb injuries. However, foot and ankle kinematics and postural control during single-leg landings in different directions are less known.Research questionDoes the difference in the direction of single-leg landing affect the foot kinematics on the frontal plane and dynamic postural stability?MethodsA cross-sectional study was conducted. Forty-nine male collegiate soccer players performed single-leg forward (FL), 45° lateral (LL), and medial (ML) direction landings. The lower limb, foot (rearfoot, midfoot, forefoot), and ankle kinematics during an impact phase were evaluated, and a curve analysis was performed using a statistical parametric mapping method to compare the three landings. The three landings were compared in terms of postural control parameters, including time to stabilization (TTS), peak of ground reaction forces (GRFs), root-mean-square of the mediolateral GRFs for 0–0.4 s (GRFML0.4), loading rate, and magnitude of horizontal GRFs from 0–0.4 s (HGRF-0.4), 0.4–2.4 s (HGRF-2.4), and 3.0–5.0 s.ResultsAnkle and rearfoot kinematics in LL exhibited smaller eversion and pronation positions than FL and ML (p < 0.01). The TTS-mediolateral (TTS-ML) was longer in the LL than in FL and ML (p < 0.001). The GRFML0.4, HGRF-0.4, and -2.4 in the LL and ML were greater than those in the FL (p < 0.001).SignificanceDirections of single-leg landing affect foot and ankle kinematics and postural stability. Specifically, the LL exhibits more inverted ankle and supinated rearfoot positions, and longer TTS-ML. Thus, the LL may induce stretching of the lateral ankle ligament. These findings can help understand foot kinematics and assess dynamic postural control.     

Ligamentous posttraumatic ankle osteoarthritis

BACKGROUND: Ankle sprains are the most common injuries in sports and recreational activities. HYPOTHESIS: Ankle osteoarthritis can be caused by ankle ligament lesions. Latency time between injury and osteoarthritis is influenced by the type and side of the injured ligaments. The side of the ligamentous lesion correlates with the hindfoot alignment. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Of a cohort of 247 patients with ankle arthritis, we reviewed data from 30 patients (33 ankles; mean age, 58.6 years) with ligamentous end-stage ankle osteoarthritis. The patients were evaluated etiologically, clinically, and radiologically. RESULTS: Etiologic analysis: 55% had a ligamentous lesion from sports injuries (soccer, 33%); 85% injured the lateral ankle ligaments, and 15% injured the medial and medial-lateral ligaments. The mean latency time between injury and osteoarthritis was 34.3 years. The survivorship rate for single severe ankle sprains was worse than that for chronic recurrent ligamentous lesions (mean latency time, 25.7 vs 38.0 years; P < .05), and the rate for medial sprains was worse than for lateral sprains (mean latency time, 27.5 vs 35.0 years; P < .05). At follow-up, the American Orthopaedic Foot and Ankle Society hindfoot score was 23.0 points, 52% had varus malalignment, 52% had persistent instability, and the mean ankle arthritis grade was 2.6 points. There was a correlation between chronic lateral ankle instability and varus malalignment. CONCLUSION: Lateral ankle sprains in sports are the main cause of ligamentous posttraumatic ankle osteoarthritis and correlate with varus malalignment. At the time of end-stage ligamentous ankle osteoarthritis, persistent instability may be encountered.     

急性外踝韧带和关节囊撕裂

报告了９０例（９１个踝关节）外踝韧带断裂和关节囊撕裂的病例，指出：外踝韧带断裂和踝前外侧关节囊的撕裂是踝足旋后伤所致；外踝韧带断裂易发生在篮球、足球等运动项目；外踝韧带断裂分为４型，对于运动员的Ⅲ度外踝韧带断裂应给予手术治疗，术后效果令人满意；外踝韧带损伤可导致腓骨长短肌的瞬时反应时延长；术后应加强踝关节跖屈、背伸、内翻和外翻肌力的练习，恢复关节的平衡性和灵活性。     

Major factors influencing rearfoot external eversion moment during barefoot walking

BackgroundExcessive rearfoot eversion motion during walking has been considered as a risk factor for lower limb chronic injuries. External moment due to ground reaction force (GRF) is the essential cause by which the rearfoot is passively everted during walking.Research questionThis study aims to identify the key factors influencing the rearfoot external eversion moments due to the GRF during walking.MethodsFrom 3-D foot coordinates and GRF data of 29 healthy participants during walking, the rearfoot external eversion moments due to the GRF and factors composing the moment (height of the ankle joint center, mediolateral GRF, mediolateral distance of the center of pressure relative to the ankle joint center in the transverse plane, vertical GRF) were computed.ResultsThe mediolateral GRF was a key factor influencing the magnitude of the rearfoot external eversion moment just after foot contact, with which pre-contact medial foot velocity was significantly correlated. During the subsequent support phase, the mediolateral distance of the center of pressure (the application point of the vertical GRF) relative to the ankle joint center was also found to be another determinant of the magnitude of the rearfoot external eversion moment.SignificanceWe succeeded in demonstrating the specific factors that most likely explain the magnitude of the rearfoot external eversion moment during initial contact and the subsequent support phase during walking. Based on the findings, specific measures to suppress the rearfoot external eversion moment could be proposed.     

Inversion injury biomechanics in functional ankle instability: a cadaver study of simulated gait

The purpose of this study was to test pathogenetic models for the "unprovoked" ankle inversion injuries seen in functional ankle unstable subjects. The consequence of spatial mal-alignment of the ankle/foot complex on the risk of producing an ankle inversion torque at heel-strike and during swing-phase follow through was analyzed in cadaver simulations. Heel-strike was simulated using a 5 degrees of freedom rig in a material testing machine. A set-up capable of accelerating lower limb specimens towards a support surface simulated swing-phase follow through. Joint excursions were monitored with flexible wire goniometers. The unloaded ankle/foot complex was placed in increasing positions of talar and subtalar joint excursions. The consequences of these settings on the behavior of the ankle/foot complex at heel-strike and when the lateral part of the foot "caught" the ground during swing-phase follow through were monitored. An inversion torque at heel-strike was first seen when the unloaded foot was set in positions exceeding 30 degrees of inversion combined with full plantar flexion and 10 degrees of internal tibial rotation. A collision between the lateral border of a 20 degrees inverted, but otherwise neutral ankle/foot complex and the ground surface during swing-phase follow through forced the foot into the full limit of inversion, plantar flexion and internal tibial rotation measurable in this set-up. Clinical consequence: The study showed that the foot/ankle complex exhibits a high degree of intrinsic stability at heel-strike. The foot will thus stabilize itself and move into normal eversion at the beginning of the stance-phase even though it is set to the ground in a substantial degree of mal-alignment. In contrast, the swing-phase collision model provides a link that can connect the small deficits in inversion angle awareness measured in chronic functional ankle unstable subjects with an increased risk in this group of sustaining ankle inversion injuries.     

Influence of foot posture on immediate biomechanical responses during walking to variable-stiffness supported lateral wedge insole designs

BackgroundNovel designs of lateral wedge insoles with arch support can alter walking biomechanics as a conservative treatment option for knee osteoarthritis. However, variations in foot posture may influence individual responses to insole intervention and these effects are not yet known.Research questionHow does foot posture influence biomechanical responses to novel designs of lateral wedge insoles with arch support?MethodsThis exploratory biomechanical investigation categorized forty healthy volunteers (age 23–34) into pronated (n = 16), neutral (n = 15), and supinated (n = 9) foot posture groups based on the Foot Posture Index. Three-dimensional gait analysis was conducted during walking with six orthotic insole conditions: flat control, lateral wedge, uniform-stiffness arch support, variable-stiffness arch support, and lateral wedge + each arch support. Frontal plane knee and ankle/subtalar joint kinetic and kinematic outcomes were compared among insole conditions and foot posture groups using a repeated measures analysis of variance.ResultsThe lateral wedge alone and lateral wedge + variable-stiffness arch support were the only insole conditions effective at reducing the knee adduction moment. However, the lateral wedge + variable-stiffness arch support had a smaller increase in peak ankle/subtalar eversion moment than the lateral wedge alone. Supinated feet had smaller ankle/subtalar eversion excursion and moment impulse than neutral and pronated feet, across all insole conditions.SignificanceSupinated feet have less mobile ankle/subtalar joints than neutral and pronated feet and, as a result, may be less likely to respond to biomechanical intervention from orthotic insoles. Supported lateral wedge insoles incorporating an arch support design that is variable-stiffness may be better than uniform-stiffness since reductions in the knee adduction moment can be achieved while minimizing increases in the ankle/subtalar eversion moment.     

Effects of medially wedged insoles on the biomechanics of the lower limbs of runners with excessive foot pronation and foot varus alignment

BackgroundExcessive foot pronation during running in individuals with foot varus alignment may be reduced by medially wedged insoles.Research questionThis study investigated the effects of a medially wedged insole at the forefoot and at the rearfoot on the lower limbs angles and internal moments of runners with excessive foot pronation and foot varus alignment.MethodsKinematic and kinetic data of 19 runners (11 females and 8 males) were collected while they ran wearing flat (control condition) and medially wedged insoles (insole condition). Both insoles had arch support. We used principal component analysis for data reduction and dependent t-test to compare differences between conditions.ResultsThe insole condition reduced ankle eversion (p = 0.003; effect size = 0.63); reduced knee range of motion in the transverse plane (p = 0.012; effect size = 0.55); increased knee range of motion in the frontal plane in early stance and had earlier knee adduction peak (p = 0.018; effect size = 0.52); reduced hip range of motion in the transverse plane (p = 0.031; effect size = 0.48); reduced hip adduction (p = 0.024; effect size = 0.50); reduced ankle inversion moment (p = 0.012; effect size = 0.55); and increased the difference between the knee internal rotation moment in early stance and midstance (p = 0.012; effect size = 0.55).SignificanceInsoles with 7˚ medial wedges at the forefoot and rearfoot are able to modify motion and moments patterns that are related to lower limb injuries in runners with increased foot pronation and foot varus alignment with some non-desired effects on the knee motion in the frontal plane.     

Snowboarder's talus fractures experimentally produced by eversion and dorsiflexion

BACKGROUND: Fracture of the lateral process of the talus is an unusual injury that has received heightened attention in recent years because of its association with snowboarding. The diagnosis is often confused with that of lateral ankle sprain. If left untreated, it can cause long-term impairment, including osteoarthritis and subtalar joint degeneration. It is generally thought to result from dorsiflexion and inversion. However, few experimental studies have been conducted to investigate the injury mechanism. HYPOTHESIS: Eversion of a dorsiflexed ankle is more likely to fracture the lateral process of the talus than inversion of a dorsiflexed ankle. STUDY DESIGN: Controlled laboratory study. METHODS: Ten cadaveric leg specimens were subjected to dynamic inversion or eversion of an axially loaded and dorsiflexed ankle. RESULTS: Inversion failed to produce any fractures in three injured specimens. However, all six specimens subjected to eversion sustained a fracture of the lateral process of the talus. CONCLUSIONS: The incidence of fracture of the lateral process of the talus was significantly higher in the eversion group compared with the inversion group. Clinical Relevance: Eversion of an axially loaded and dorsiflexed ankle may be an important injury mechanism for fracture of the lateral process of the talus among snowboarders.     

Foot and Ankle Injuries in Professional Soccer Players

Soccer is a physically demanding and highly competitive sport with a high rate of injuries. The foot and the ankle joint are especially at danger. Risk factors of foot and ankle injuries in soccer players are: lack of structured warm up training, neuromuscular deficits, inadequate training, chronic fatigue, previous injuries, foul play, artificial turf, and others. While the most common injury is the ankle sprain, complex injuries like fractures, ligament tears, and cartilage damage can occur. Such injuries have a high impact on the player's career. Professional soccer players are pressured to meet the expectations of the clubs, and the public. While most injuries to the foot and ankle joint can be treated conservatively, complex injuries require anatomic reconstruction to allow for quick rehabilitation and return to play earliest possible.     

Telemark skiing injuries: an 11-year study

This study evaluated telemark injuries in a Swedish ski area in terms of injury ratio, location, and causes over time. During the seasons of 1989-2000 all injured telemark skiers ( n=94) who attended the medical center in T?rnaby, Sweden, within 48 h after the accident were registered and asked to fill in an injury form. A control group of noninjured telemark skiers were interviewed in the season of 1999-2000. The most common cause of injury was fall (70%) and the injury ratio was 1.2. There was a higher proportion of beginners in the injured population, and they had a fall/run ratio of 0.7, compared with 0.3 for average and advanced skiers. Ankle/foot injuries were most common (28% of injuries) followed by knee (20%) and head/neck (17%). The ankle/foot injuries decreased from 35% to 22% in the seasons 1989-1995 to 1995-2000. Beginners had more ankle/foot injuries than skilled participants. The severity of ankle/foot injuries classified as the Abbreviated Injury Scale group 2 or higher decreased from 33% to 21% during the study period. Twenty-seven percent used plastic and 73% leather boots. We found no association between boot material and ankle/foot injuries. The proportion of high boots with two or more buckles was 51%. High boots appeared to be protective against ankle/foot injuries. The proportion of high boots increased from 24% to 67% during the study period. Thus ankle/foot injuries were the most common injury location, but have decreased over time. The severity of these injuries has also decreased. A possible explanation could be the increased use of high boots.     

Injuries to dancers. Prevalence, treatment and prevention

Studies from the USA and UK indicate that the back, neck and shoulder and the lower limb (particularly the hip, knee, ankle and foot) are the most frequent sites of injury among dancers. Most injuries are soft tissue injuries. Most dancers experience injuries at some time and about half have chronic injuries. Shoulder injuries appear to be caused by frequent or unaccustomed lifting, and are treated by rest and oral anti-inflammatory medication. Back injuries include sprains, prolapsed or herniated intervertebral discs, and spondylolytic stress fractures. Several risk factors, especially training error, have been identified for overuse injuries. Hip injuries include degenerative changes and osteoarthritis, stress fractures, bursitis and damage to the sciatic nerve. The most common foot injury is an anterior lateral ligament sprain, which may lead to permanent instability in the ankle. More soundly based research into the prevalence, diagnosis and treatment of injuries is needed.     

Propensity for osteoarthritis and lower limb joint pain in retired professional soccer players

OBJECTIVE: To quantify the prevalence of osteoarthritis and the severity of pain in the lower limb joints of players retired from English professional soccer. METHOD: An anonymous self administered questionnaire was distributed to 500 former players registered with the English Professional Footballers' Association. The questionnaire was designed to gather information on personal details, physical activity loading patterns, history of lower limb joint injury, and current medical condition of the lower limb joints. RESULTS: Of 500 questionnaires distributed, 185 (37%) were returned. Nearly half of the respondents (79: 47%) retired because of injury; 42% (33) were acute injuries and 58% (46) chronic injuries. Most of the acute injuries that led to early retirement were of the knee (15: 46%), followed by the ankle (7: 21%) and lower back (5: 15%). Most of the chronic injuries that led to early retirement were also of the knee (17: 37%), followed by the lower back (10: 22%) and the hip (4: 9%). Of all respondents, 32% (59) had been medically diagnosed with osteoarthritis in at least one of the lower limb joints. More respondents had been diagnosed with osteoarthritis in the knee joints than either the ankle or the hip joints. Significantly (p<0.001) more respondents reported pain in one lower extremity joint during one or more daily activities than those who did not (joint pain: 137, 80%; no joint pain: 35, 20%). CONCLUSION: The risk for professional soccer players of osteoarthritis in at least one of the lower extremity joints is very high and significantly greater than for the general population. The results support the suggestion that professional soccer players should be provided with health surveillance during their playing career.     

Prevention of non-contact anterior cruciate ligament injuries in soccer players. Part 1: Mechanisms of injury and underlying risk factors

Soccer is the most commonly played sport in the world, with an estimated 265 million active soccer players by 2006. Inherent to this sport is the higher risk of injury to the anterior cruciate ligament (ACL) relative to other sports. ACL injury causes the most time lost from competition in soccer which has influenced a strong research focus to determine the risk factors for injury. This research emphasis has afforded a rapid influx of literature defining potential modifiable and non-modifiable risk factors that increase the risk of injury. The purpose of the current review is to sequence the most recent literature that reports potential mechanisms and risk factors for non-contact ACL injury in soccer players. Most ACL tears in soccer players are non-contact in nature. Common playing situations precluding a non-contact ACL injury include: change of direction or cutting maneuvers combined with deceleration, landing from a jump in or near full extension, and pivoting with knee near full extension and a planted foot. The most common non-contact ACL injury mechanism include a deceleration task with high knee internal extension torque (with or without perturbation) combined with dynamic valgus rotation with the body weight shifted over the injured leg and the plantar surface of the foot fixed flat on the playing surface. Potential extrinsic non-contact ACL injury risk factors include: dry weather and surface, and artificial surface instead of natural grass. Commonly purported intrinsic risk factors include: generalized and specific knee joint laxity, small and narrow intercondylar notch width (ratio of notch width to the diameter and cross sectional area of the ACL), pre-ovulatory phase of menstrual cycle in females not using oral contraceptives, decreased relative (to quadriceps) hamstring strength and recruitment, muscular fatigue by altering neuromuscular control, decreased “core” strength and proprioception, low trunk, hip, and knee flexion angles, and high dorsiflexion of the ankle when performing sport tasks, lateral trunk displacement and hip adduction combined with increased knee abduction moments (dynamic knee valgus), and increased hip internal rotation and tibial external rotation with or without foot pronation. The identified mechanisms and risk factors for non-contact ACL injuries have been mainly studied in female soccer players; thus, further research in male players is warranted. Non-contact ACL injuries in soccer players likely has a multi-factorial etiology. The identification of those athletes at increased risk may be a salient first step before designing and implementing specific pre-season and in-season training programs aimed to modify the identified risk factors and to decrease ACL injury rates. Current evidence indicates that this crucial step to prevent ACL injury is the only option to effectively prevent the sequelae of osteoarthritis associated with this traumatic injury.     

Does a balance deficit persist in Australian football players with previous lower limb ligament injury?

A history of lower limb ligament injury is a commonly-cited risk factor for another similar injury. During the acute phase of injury, there is a balancing skill deficit in the injured limb. It has been unclear as to whether this deficit persists in the medium-to-long term for previously injured Australian footballers, contributing to the risk of re-injury. This study compared the balance ability of footballers with and without previous lower limb ligament injury and, for previously injured players, the balance ability of the previously injured limb to the opposite uninjured limb. A total of 216 players from 6 teams from the Australian Football League were tested. The balance task comprised stepping on to a foam mat on top of a force plate and maintaining one-legged balance. The subjects were divided into 4 groups based on their injury history: all ankle injuries to only one limb, recent ankle injuries to only one limb (within the last 12 months), knee ligament injury only to one limb, and no previous ankle or knee ligament injury. Statistical analysis revealed that there was no significant difference between the balance scores of any of the previously injured players and those with no previous lower limb ligament injury. There was no significant difference between the balance score of the previously injured limb with the opposite uninjured limb. It appears that a balance deficit does not persist in Australian Football players with previous lower limb ligament injury.     

Assessing performance,stability, and cleat comfort/support in collegiate club soccer players using prophylactic ankle taping and bracing

Soccer athletes at all levels of play are keenly aware of their equipment needs including cleat wear, and want to be protected from injury but without impeding on-field performance. Ankle injury is a common disorder that is prevalent in the sport of soccer and recent improvements in ankle prophylaxis interventions have proven effective. The aim of this study was to determine if the use of elastic taping or a neoprene sleeve alters performance, stability, and cleat comfort/support in soccer players compared to wearing a soccer cleat without any external support. Twenty male collegiate club soccer players were recruited and randomly assigned to the three conditions (untaped control, taped, neoprene sleeve). Performance testing and comfort/support assessment for each condition took place in one on-field test session, while stability testing was completed during a separate laboratory session. The only significant finding was improved inversion/eversion stability in both the tape and sleeve conditions as compared to the cleated condition. The addition of tape or a sleeve did not have an adverse effect on performance or comfort during functional and stability testing, and should therefore be considered as a method to decrease ankle injuries in soccer athletes as external supports provide increased stability in inversion/eversion range of motion.     

Single‐leg drop landing motor control strategies following acute ankle sprain injury

No research currently exists investigating the effect of acute injury on single‐limb landing strategies. The aim of the current study was to analyze the coordination strategies of participants in the acute phase of lateral ankle sprain (LAS) injury. Thirty‐seven participants with acute, first‐time LAS and 19 uninjured participants completed a single‐leg drop landing task on both limbs. Three‐dimensional kinematic (angular displacement) and sagittal plane kinetic (moment‐of‐force) data were acquired for the joints of the lower extremity from 200 ms pre‐initial contact (IC) to 200 ms post‐IC. The peak magnitude of the vertical component of the ground reaction force (GRF) was also computed. Injured participants displayed a bilateral increase in hip flexion, with altered transverse plane kinematic profiles at the knee and ankle for both limbs (P < 0.05). This coincided with a reduction in the net‐supporting flexor moment of the lower extremity (P < 0.05) and magnitude of the peak vertical GRF for the injured limb (21.82 ± 2.44 N/kg vs 24.09 ± 2.77 N/kg; P = 0.013) in injured participants compared to control participants. These results demonstrate that compensatory movement strategies are utilized by participants with acute LAS to successfully reduce the impact forces of landing.     

Clinical association of acute lateral ankle sprain with syndesmotic involvement: a stress radiography and magnetic resonance imaging study

BACKGROUND: Information concerning the clinical association between syndesmosis injury and grade of lateral ankle ligament damage would aid in the diagnosis and treatment of ankle sprains. HYPOTHESIS: Evaluation of lateral ligament injury in terms of percentage tear of both the anterior talofibular and calcaneofibular ligaments can provide information on the extent of syndesmotic involvement. STUDY DESIGN: Prospective cohort study. METHODS: Twenty-five patients volunteered to have magnetic resonance imaging examinations performed and 21 volunteered to undergo graded stress radiographs. Talar tilt angles were measured from radiographs taken with 0, 6, 9, 12, and 15 daN of force applied medially just above the ankle joint, and the percentage of ligament tear and grade of injury were determined. Scans were obtained with the foot in neutral and plantar flexion to image the anterior talofibular and calcaneofibular ligaments. RESULTS: Grades of lateral ligament injury determined by magnetic resonance imaging and graded stress radiography were the same. The extent of syndesmotic injury could be assessed for all patients. CONCLUSIONS: Intact tibiofibular ligaments were found equally frequently among patients with normal or any grade of lateral ligament damage, but the more severe injuries to the syndesmotic ligaments were associated with normal or minimally traumatized lateral ligaments. The inverse correlation can be explained on the basis of the difference between the mechanisms that precipitate these injuries.