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BACKGROUND: The purpose of this study was to determine how closely the present designs of ankle prostheses mimic the unique requirements of the foot and ankle. The three-dimensional range of motion (ROM) of the ankle joint complex, before and after ankle arthrodesis and after implantation of three currently used total ankle prostheses, was investigated. METHODS: The three-dimensional ROM was determined in six fresh-frozen cadaver leg specimens using a 6-df device with an axial load of 200 N and a four-camera high-speed video system. A moment of 100 Nm was applied to the footplate to determine the ROM in the sagittal (dorsiflexion and plantarflexion) and frontal (inversion and eversion) planes. The same moment was applied to the tibia to determine the ROM for the internal and external tibial rotation. The measurements were performed for the normal ankle, the fused ankle, and the AGILITY, HINTEGRA, and S.T.A.R. prostheses. RESULTS: Compared to the normal condition, the ROM for dorsiflexion and plantarflexion was changed for all surgical interventions. The changes were highest for the ankle arthrodesis. The changes due to the prostheses were significantly less than the changes due to ankle arthrodesis. Compared to the normal condition, the total ROM for inversion/eversion was slightly decreased by the fused ankle and not changed by the three-component prostheses (HINTEGRA, S.T.A.R.). However, the ROM for inversion/eversion was significantly higher for the two-component prosthesis, AGILITY. The ROM for internal and external tibial rotation was not altered by the AGILITY and HINTEGRA ankle, but it was significantly reduced by the ankle arthrodesis. S.T.A.R. showed a significant shift of the total ROM toward internal tibial rotation. CONCLUSIONS: The three tested ankle joint prostheses changed the ROM of the ankle joint complex less than ankle fusion did. Total ankle prostheses were shown to replicate normal joint ROM closely. However, ankle arthrodesis was found to reduce the ROM substantially in all three planes: the sagittal, frontal, and horizontal planes. CLINICAL IMPLICATIONS: With respect to the ROM, total ankle replacement changes the natural ankle joint condition less than ankle arthrodesis, which reduces the ROM in all three planes and might increase stress in adjacent structures. The prosthesis that replicated the normal ankle joint ROM best was the one with the most anatomical design.
OBJECTIVE: To review the surgical indications, techniques, biomechanical testing, and clinical results reported for the most common surgical techniques used to treat ankle instability. DATA SOURCES: We searched MEDLINE from 1960-2001 using the terms ankle instability, functional ankle instability, mechanical ankle instability, ankle ligament surgery, Broström, Chrisman-Snook, and Evans. DATA SYNTHESIS: Although 80% to 85% of acute ankle sprains are successfully treated with a functional ankle-rehabilitation program, the remaining 15% to 20% have recurrent ankle instability and reinjury, necessitating surgical intervention. The fundamentals of the surgical approach to lateral ankle instability are based on the anatomy of the lateral ankle ligaments, the anterior talofibular ligament, and the calcaneofibular ligament. Ankle-instability surgery has been broadly divided into an anatomic repair consisting of an imbrication of the lateral ligamentous complex and an ankle-ligament reconstruction. An ankle-ligament reconstruction weaves a harvested tendon graft, most commonly the peroneus brevis, to augment the lateral ligaments of the ankle. Goals of surgery are to reestablish ankle stability and function without compromising motion and without complications. Anatomic repair and imbrication of the lateral ligament complex with the Gould modification has an 85% to 95% success rate, and the risk of associated nerve injuries is low. This approach provides increased stability by reinforcing local host tissue, preserving subtalar and talocrural motion, eliminating the comorbidity associated with tendon-graft harvest, and offering a quicker functional recovery. One concern in using the anatomic approach is the resultant strength of the repair, although the literature does not support this concern. Ankle-reconstruction procedures that sacrifice tendons are thought to provide a stronger construct, and hence, more stability. This increased stability results in loss of talocrural and subtalar range of motion, prolonging recovery and decreasing sport performance. Adjacent nerve injury is more common with ankle-ligament reconstruction. CONCLUSIONS/RECOMMENDATIONS: Based on the literature, we believe that a modified Broström lateral-ligament repair should be considered the first choice for persistent ankle instability refractory to a functional ankle-rehabilitation protocol. Ankle reconstruction with tendon augmentation should be reserved for patients with generalized ligamentous laxity or long-standing ligamentous insufficiency or as a salvage procedure in a patient with a failed modified Broström lateral-ligament repair.
BACKGROUND: There is renewed interest in total ankle arthroplasty as an alternative to ankle fusion in the treatment of end-stage ankle arthritis. Despite a lack of long-term data on the clinical outcomes associated with these implants, the use of ankle arthroplasty is expanding. The purpose of this cost-effectiveness analysis was to evaluate whether the currently available literature justifies the emerging use of total ankle arthroplasty. This study also identifies thresholds for the durability and function of ankle prostheses that, if met, would support more widespread dissemination of this new technology. METHODS: A decision model was created for the treatment of ankle arthritis. The literature was reviewed to identify possible outcomes and their probabilities following ankle fusion and ankle arthroplasty. Each outcome was weighted for quality of life with use of a utility factor, and effectiveness was expressed in units of quality-adjusted life years. Gross costs were estimated from Medicare charge and reimbursement data for the relevant codes. The effect of the uncertainty of estimates of costs and effectiveness was assessed with sensitivity analysis. RESULTS: The reference case of our model assumed a ten-year duration of survival of the prosthesis, resulting in an incremental cost-effectiveness ratio for ankle arthroplasty of $18,419 per quality-adjusted life year gained. This reflects a gain of 0.52 quality-adjusted life years at a cost of $9578 when ankle arthroplasty is chosen over fusion. This ratio compares favorably with the cost-effectiveness of other medical and surgical interventions. Sensitivity analysis determined that the cost per quality-adjusted life year gained with ankle arthroplasty rises above $50,000 if the prosthesis is assumed to fail before seven years. Treatment options with ratios above $50,000 per quality-adjusted life year are commonly considered to have limited cost-effectiveness. This threshold is also crossed when the theoretical functional advantages of ankle arthroplasty are eliminated in sensitivity analysis. CONCLUSIONS: The currently available literature has not yet shown that total ankle arthroplasty predictably results in levels of durability and function that make it cost-effective at this time. However, the reference case of this analysis does demonstrate that total ankle arthroplasty has the potential to be a cost-effective alternative to ankle fusion. This reference case assumes that the theoretical functional advantages of ankle arthroplasty over ankle fusion will be borne out in future clinical studies. Performance of total ankle replacement will be better justified if these thresholds are met in published long-term clinical trials.
OBJECTIVE: To describe the functional anatomy of the ankle complex as it relates to lateral ankle instability and to describe the pathomechanics and pathophysiology of acute lateral ankle sprains and chronic ankle instability. DATA SOURCES: I searched MEDLINE (1985-2001) and CINAHL (1982-2001) using the key words ankle sprain and ankle instability. DATA SYNTHESIS: Lateral ankle sprains are among the most common injuries incurred during sports participation. The ankle functions as a complex with contributions from the talocrural, subtalar, and inferior tibiofibular joints. Each of these joints must be considered in the pathomechanics and pathophysiology of lateral ankle sprains and chronic ankle instability. Lateral ankle sprains typically occur when the rearfoot undergoes excessive supination on an externally rotated lower leg. Recurrent ankle sprain is extremely common; in fact, the most common predisposition to suffering a sprain is the history of having suffered a previous ankle sprain. Chronic ankle instability may be due to mechanical instability, functional instability, or most likely, a combination of these 2 phenomena. Mechanical instability may be due to specific insufficiencies such as pathologic laxity, arthrokinematic changes, synovial irritation, or degenerative changes. Functional instability is caused by insufficiencies in proprioception and neuromuscular control. CONCLUSIONS/RECOMMENDATIONS: Lateral ankle sprains are often inadequately treated, resulting in frequent recurrence of ankle sprains. Appreciation of the complex anatomy and mechanics of the ankle joint and the pathomechanics and pathophysiology related to acute and chronic ankle instability is integral to the process of effectively evaluating and treating ankle injuries.
BACKGROUND: Functional ankle instability or a subjective report of ;;giving way'' at the ankle may be present in up to 40% of patients after a lateral ankle sprain. Damage to mechanoreceptors within the lateral ankle ligaments after injury is hypothesized to interrupt neurologic feedback mechanisms resulting in functional ankle instability. The altered input can lead to weakness of muscles surrounding a joint, or arthrogenic muscle inhibition. Arthrogenic muscle inhibition may be the underlying cause of functional ankle instability. Establishing the involvement of arthrogenic muscle inhibition in functional ankle instability is critical to understanding the underlying mechanisms or chronic ankle instability. The purpose of this investigation was to determine if arthrogenic muscle inhibition is present in the ankle joint musculature of patients exhibiting unilateral functional ankle instability. METHODS: Twenty-nine subjects, 15 with unilateral functional ankle instability and 14 healthy control subjects, consented to participate. Bilateral soleus, peroneal, and tibialis anterior H-reflex and M-wave recruitment curves were obtained. Maximal H-reflex and maximal M-wave values were identified and the H:M ratios were calculated for data analysis. Separate 1 x 2 ANOVA were done for both the functional ankle instability and control groups to evaluate differences between limbs on the H:M ratios. Bonferroni multiple comparison procedures were used for post hoc comparisons (p < or = 0.05). RESULTS: The soleus and peroneal H:M ratios for subjects with functional ankle instability were smaller in the injured limb when compared with the uninjured limb (p < 0.05). No limb difference was detected for the tibialis anterior H:M ratio in the functional ankle instability group (p = 0.904). No side-to-side differences were detected for the H:M ratios in patients reporting no history of ankle injury (p > 0.05). CONCLUSIONS: Depressed H:M ratios in the injured limb suggest that arthrogenic muscle inhibition is present in the ankle musculature of patients exhibiting functional ankle instability. Establishing and using therapeutic techniques to reverse arthrogenic muscle inhibition may reduce the incidence of functional ankle instability.
BACKGROUND: Stance-control knee-ankle-foot orthoses permit free knee motion in swing while providing knee flexion resistance in stance for individuals with quadriceps muscle weakness. However, some stance-control knee-ankle-foot orthoses require full knee extension to engage the knee-joint lock, thereby not providing knee support when climbing stairs or stepping over curbs. Stance-control knee-ankle-foot orthoses that do support a flexed knee are either heavy, bulky, expensive, offer a limited number of locking positions, or cause noise. This paper presents a preliminary kinematic evaluation of a new stance-control knee-ankle-foot orthosis that was designed to address these limitations. METHODS: Kinematic gait analysis was performed on three male knee-ankle-foot-orthosis users with knee extensor weakness in at least one limb (mean age: 56.3 years (SD 4.0)). Three walking trials were performed with the subjects' current knee-ankle-foot-orthosis and then the new stance-control knee-ankle-foot orthosis (non-randomized before-after trial). Subjects completed a questionnaire about the new stance-control knee-ankle-foot orthosis and current knee-ankle-foot-orthosis. FINDINGS: A mean increase in knee flexion of 21.1 degrees (SD 8.2) during swing and a greater total knee range of motion was found when walking with the new stance-control knee-ankle-foot orthosis. Two knee-ankle-foot-orthosis users experienced a reduction in pelvic obliquity and hip abduction angle abnormalities when walking with the stance-control knee-ankle-foot orthosis. Two out of three subjects preferred walking with the new stance-control knee-ankle-foot orthosis over their prescribed knee-ankle-foot-orthosis. INTERPRETATION: The new stance-control knee-ankle-foot orthosis permitted improved gait kinematics for knee-ankle-foot-orthosis users while providing knee support in stance and free knee motion in swing at appropriate instants in the gait cycle. Overall, the new stance-control knee-ankle-foot orthosis provided more natural gait kinematics for orthosis users compared to conventional knee-ankle-foot-orthoses.
The goal of this study was to describe the movement patterns of the ankle joint whilst standing on one leg. Ten healthy adult females (age 24 +/- 5.3 years) performed a one-legged standing task with eyes closed. Force platform recordings and video analyses were used to describe the kinematic and kinetic characteristics of the ankle joint during this task. A rocking movement of the foot (heel inversion-eversion) was documented by examining instances of extreme ankle displacement. Extreme ankle displacement was defined as any instant when the ankle position was more than +/- 2 SD away from the mean ankle joint position. Extreme values of lateral and medial ankle joint displacement were 14.8 and 9.2 mm, correspondingly. These instances of extreme foot inversion-eversion were characterized by large medial-lateral displacement of the gravity line (GLP) and center of pressure (COP) and large horizontal forces. Comparing instances of extreme ankle joint displacement to periods of non-extreme ankle displacement, the ankle joint moment remained fairly constant, averaging 8.4 +/- 4 and 6.9 +/- 3.5 Nm, respectively. The moment about the 'body-minus-foot' center of mass generated by the ankle joint reaction force, however, was on average over four times larger during instances of extreme ankle displacement (3.4 +/- 2.8 Nm), than during periods of non-extreme ankle displacement (0.8 +/- 0.4 Nm). In utmost situations, the moment due to the joint reaction force was up to 73% of the ankle joint moment. These results suggest that at least two different techniques are used to maintain balance during one-legged standing. The first technique, termed the ankle torque technique, involves a large restorative moment at a stationary ankle joint for balance maintenance. The other technique, the shear force technique, involves a large horizontal force at a moving ankle joint for balance maintenance. During non-extreme periods, balance was maintained primarily through the ankle torque technique. During extreme instances, a combination of both techniques was observed.
BACKGROUND: Interest in mobile-bearing total ankle arthroplasty has increased in recent years. However, to our knowledge, no study has focused exclusively on patients with the diagnosis of inflammatory joint disease or has provided a detailed analysis of the risk factors for failure. METHODS: A prospective observational study of the results of cementless mobile-bearing total ankle arthroplasty in patients with inflammatory joint disease (mainly rheumatoid arthritis) was conducted at two centers. Ninety-three total ankle arthroplasties were performed. The LCS (low contact stress) prosthesis was used initially, in nineteen ankles, between 1988 and 1992, and a modification of the LCS prosthesis, the Buechel-Pappas design, was used in seventy-four ankles between 1993 and 1999. Clinical and radiographic follow-up was performed at yearly intervals. Three clinical scoring systems were used, and any complication was recorded throughout follow-up. Actuarial survival (with revision as the end point), multivariate analysis, and a competing risk approach were used to describe the long-term outcome. RESULTS: The clinical result at one year after surgery showed a significant improvement in the scores on all three scoring systems (p < 0.05). Ankle dorsiflexion (mean, 7 degrees ) also improved significantly (p < 0.05) compared with the preoperative state. The most frequent complication was a malleolar fracture, which occurred in twenty ankles. Only when it occurred in combination with a deformity in the frontal plane did this complication have an adverse effect on the end result. At a mean follow-up of eight years, seventeen patients (twenty-one ankles) had died and fifteen ankles had been revised because of aseptic loosening (six ankles), primary or secondary axial deformity with edge-loading (six ankles), deep infection (two ankles), and a severe wound-healing problem (one ankle), leaving fifty-seven ankles (61%) that were evaluated. The mean overall survival rate at eight years was 84%. An increased failure rate was encountered in ankles with a preoperative deformity in the frontal plane of >10 degrees (p = 0.03) and in ankles in which an undersized tibial component had been implanted (p = 0.02). CONCLUSIONS: Mobile-bearing total ankle arthroplasty is a valid treatment option for the rheumatoid ankle if proper indications are used. Aseptic loosening and persistent deformity are the most important modes of failure.
Ankle inversion sprain is common in rugby. This review outlines research evidence relating to the effects of external ankle support by means of bracing and taping, on the incidence of ankle injuries, how performance is affected by support, how support may act at the joint (with respect to end range of motion, strength, resistive torque, muscle activation patterns and proprioception) to prevent injury, and how exercise changes the effectiveness of support. In addition, the implications of the laws of rugby for the use of external support are discussed. Prospective epidemiological studies have shown a decrease in the incidence of ankle injury with external ankle support use. The effectiveness of external ankle support was dependent upon the material properties and application method of the tape or brace, and on the athlete's status of ankle stability or previous injury. Experimental studies have indicated that the degree of ankle inversion restriction provided, and the degree of loss of restriction after exercise, were dependent upon the external support tested. External ankle support has been reported to have no effect on performance, or to have an adverse effect on performance in a variety of movement tasks. No prophylactic external ankle support has been shown to improve performance. If an external support is to provide mechanical support to a ligament it should exceed the strength of the ligament, which for the anterior fibular ligament is a force limit of between 6 and 56 kg. Tape can provide only limited mechanical support of the ankle joint complex, but it may have proprioceptive effects. Taping may work as a psychological reminder, so that the athlete consciously moderates lower limb-loading behaviour. There is equivocal evidence of the effect of brace use on ground reaction force excursions, balance ability and ankle strength. It is concluded that while there have been many investigations of the effects of tape and some forms of brace on ankle range of motion with and without exercise, there is equivocal evidence regarding the mechanism by which an external support acts. It is recommended that future research address the effects of external ankle support during dynamic exercise and that brace manufacturers utilise the information in the development of future brace designs to help reduce the risk of ankle inversion sprain injury. As external support can decrease the incidence of ankle inversion sprain the International Rugby Board should consider the use of ankle braces in rugby, allowing for stiff lateral components of the brace.
STUDY DESIGN: A comparative study. OBJECTIVES: To assess whether in subjects with unilateral chronic ankle instability the dynamic reaction time of the affected ankle differs from the healthy ankle and from ankles of a control group. BACKGROUND: Reaction time is an essential element in joint protection against sudden unexpected excessive movement requiring fast and coordinated muscle action. During a sudden ankle inversion movement, a reflex action of the evertor muscles is needed to counteract the movement. Adequate neuromuscular response is crucial and a delayed response could contribute to inversion trauma and subsequently to chronic ankle instability. The isokinetic dynamometer acceleration time (ACC-TIME) provides valuable information on dynamic neuromuscular ability. MATERIAL AND METHODS: Patients with unilateral chronic ankle instability (n = 11) and healthy individuals in a control group (n = 11) were tested on an isokinetic dynamometer during 3 sets of 3 reciprocal inversion/eversion movements of both ankles at 30 degrees/s and 120 degrees/s. Analysis of variance models were used to compare the ACC-TIME of the affected ankle to the unaffected ankle of the same subjects and a control group. RESULTS: For the evertor muscles at 30 degrees/s and 120 degrees/s a significantly prolonged ACC-TIME was found when comparing the affected ankles to the contralateral ankles and both ankles of the control group. For the invertor muscles at 120 degrees/s a significantly prolonged ACC-TIME was found when comparing the affected ankle to the unaffected ankles of patients and those of the control group. CONCLUSIONS: Because the most important evertor muscles are innervated by the fibular nerve, the significantly prolonged ACC-TIME of the affected ankle is consistent with the finding of a lower motor nerve conduction velocity of the fibular nerve after inversion trauma. The results support the concept of a delayed neuromuscular response as an important factor in the etiology of chronic ankle instability.
Ankle arthroplasties using metal and polyethylene prostheses were done on 28 patients (30 ankles) with painful osteoarthritis or rheumatoid arthritis between 1975 and 1980. Significant loosening and subsidence of the metal prostheses occurred in most patients, and ceramic prostheses were introduced in 1980. Ceramic prostheses with or without cement were used to replace 60 ankles in 56 patients with painful arthritis between 1980 and 1991. Revision surgery was required for five patients (five ankles) during the followup period (mean, 12 years 6 months). Loosening and subsidence of the prostheses were seen in 50% of patients within 5 years after the index procedure. As a result, a new design of bead-formed alumina coated with hydroxyapatite was used. A tibial prosthesis fixed to the posterior cortex of the tibia with a screw was used from 1991. These new ceramic prostheses were used to replace 70 ankles in 62 patients between 1991 and 2000. Thirty-six patients (36 ankles) with a mean age of 71 years (range, 50-87 years) had osteoarthritis, and 26 patients (31 ankles) with a mean age of 60 years (range, 41-76 years) had rheumatoid arthritis. During followup, with an average of 5 years 2 months, three patients (three ankles) required revision surgery (one for infection, two for talar necrosis). Overall results for patients with osteoarthritis were excellent in 21 ankles, good in 10 ankles, fair in two, ankles and poor in zero ankles. Results in patients with rheumatoid arthritis were excellent in five ankles, good in 16 ankles, fair in three ankles, and poor in two. In the intermediate study, 29 patients (31 ankles; 91.2%) with osteoarthritis and 19 patients (21 ankles; 76.9%) with rheumatoid arthritis were satisfied with the short-time results of arthroplasty.
OBJECTIVES: To determine the rate of ankle injury and examine risk factors of ankle injuries in mainly recreational basketball players. METHODS: Injury observers sat courtside to determine the occurrence of ankle injuries in basketball. Ankle injured players and a group of non-injured basketball players completed a questionnaire. RESULTS: A total of 10 393 basketball participations were observed and 40 ankle injuries documented. A group of non-injured players formed the control group (n = 360). The rate of ankle injury was 3.85 per 1000 participations, with almost half (45.9%) missing one week or more of competition and the most common mechanism being landing (45%). Over half (56.8%) of the ankle injured basketball players did not seek professional treatment. Three risk factors for ankle injury were identified: (1) players with a history of ankle injury were almost five times more likely to sustain an ankle injury (odds ratio (OR) 4.94, 95% confidence interval (CI) 1.95 to 12.48); (2) players wearing shoes with air cells in the heel were 4.3 times more likely to injure an ankle than those wearing shoes without air cells (OR 4.34, 95% CI 1.51 to 12.40); (3) players who did not stretch before the game were 2.6 times more likely to injure an ankle than players who did (OR 2.62, 95% CI 1.01 to 6.34). There was also a trend toward ankle tape decreasing the risk of ankle injury in players with a history of ankle injury (p = 0.06). CONCLUSIONS: Ankle injuries occurred at a rate of 3.85 per 1000 participations. The three identified risk factors, and landing, should all be considered when preventive strategies for ankle injuries in basketball are being formulated.
Eighteen intact ankles were loaded with inversion-eversion and anterior-posterior forces, and motions of the talus and calcaneus were measured. Ankles were tested in neutral, 15 degrees of dorsiflexion, and 15 degrees of plantar flexion. The anterior talofibular ligament was then sectioned and testing was repeated. In half the specimens the calcaneofibular ligament was also sectioned followed by repeat testing. The Evans, Watson-Jones, and Chrisman-Snook procedures were performed on each ankle and testing was repeated. With inversion-eversion loading, only the Chrisman-Snook reconstruction resulted in a significantly more stable ankle joint complex than in the anterior talofibular ligament cut ankles. All three reconstructions increased ankle stability over the anterior talofibular and calcaneofibular ligament cut state. With anterior-posterior loading, all reconstructions resulted in a significantly more stable ankle joint complex than the anterior talofibular ligament cut ankles. The Evans and Chrisman-Snook procedures resulted in more stability than the anterior talofibular and calcaneofibular ligament cut ankles. There was no difference in subtalar joint motion with inversion-eversion loading among ankles with the anterior talofibular ligament cut and those with any of the reconstructions. For the anterior talofibular and calcaneofibular ligament cut ankles, subtalar joint motion was similar to that in intact ankles after each reconstruction. All three reconstructions resulted in ankles with significantly less subtalar joint motion with anterior-posterior loading than ankles with the anterior talofibular ligament cut or with the anterior talofibular and calcaneofibular ligaments cut. The Chrisman-Snook procedure resulted in ankles with significantly less motion than intact ankles.
OBJECTIVE: Taping and bracing are thought to decrease the incidence of ankle sprains; however, few investigators have addressed the effect of preventive measures on the rate of ankle sprains. Our purpose was to examine the effectiveness of ankle taping and bracing in reducing ankle sprains by applying a numbers-needed-to-treat (NNT) analysis to previously published studies. DATA SOURCES: We searched PubMed, CINAHL, SPORT Discus, and PEDro for original research from 1966 to 2002 with key words ankle taping, ankle sprains, injury incidence, prevention, ankle bracing, ankle prophylaxis, andnumbers needed to treat. We eliminated articles that did not address the effects of ankle taping or bracing on ankle injury rates using an experimental design. DATA SYNTHESIS: The search produced 8 articles, of which 3 permitted calculation of NNT, which addresses the clinical usefulness of an intervention by providing estimates of the number of treatments needed to prevent 1 injury occurrence. In a study of collegiate intramural basketball players, the prevention of 1 ankle sprain required the taping of 26 athletes with a history of ankle sprain and 143 without a prior history. In a military academy intramural basketball program, prevention of 1 sprain required bracing of 18 athletes with a history of ankle sprain and 39 athletes with no history. A study of ankle bracing in competitive soccer players produced an NNT of 5 athletes with a history of previous sprain and 57 without a prior injury. A cost- benefit analysis of ankle taping versus bracing revealed taping to be approximately 3 times more expensive than bracing. CONCLUSIONS/RECOMMENDATIONS: Greater benefit is achieved in applying prophylactic ankle taping or bracing to athletes with a history of ankle sprain, compared with those without previous sprains. The generalizability of these results to other physically active populations is unknown.
OBJECTIVE: The appearance of fluid in tendon sheaths of the ankle joint and in ankle articulations seems to vary. To determine the degree of this variability and to see if fluid occurs in normal ankles, we evaluated the presence, amount, and distribution of joint fluid as seen on MR images of normal and abnormal ankles. MATERIALS AND METHODS: The study included 40 normal ankles of volunteers, 15 ankles of patients with disorders of the posterior tibial tendon, 73 ankles of patients with disorders not involving tendons studied (occult fractures, osteochondritis dissecans, and Achilles tendon disorders), and 46 asymptomatic ankles of patients with disorders of the opposite ankle. We analyzed the MR images of these ankles to determine the volume of fluid in the ankle and subtalar joints. We also analyzed the relative volumes of fluid in tendon sheaths. We then compared the results in patients who had symptoms with those in asymptomatic subjects and developed an algorithm of fluid interrelationships. RESULTS: Most patients had fluid in the ankle (77%) and subtalar joints (72%). Fluid was common around all tendons except the extensor tendons. Large amounts of fluid were particularly common around the flexor hallucis longus tendon (14%). No statistically significant difference in the prevalence or relative volumes of fluid in the subtalar or ankle joints or tendon sheaths was found between normal and abnormal ankles. A close relationship was found between volumes of fluid between tendons, usually those in close proximity to each other. We found no correlation between fluid in the subtalar and ankle joints. CONCLUSION: Our results show that fluid in the articulations and tendon sheaths of the ankle is common in asymptomatic patients, and the amounts of fluid are not significantly different from the amounts in patients with symptoms. There also appear to be complex interrelationships between fluid seen in the joint and in tendon sheaths.
The purposes of this study were (1) to define and estimate the direction and amount of the energy transfer between the knee and ankle through gastrocnemius (GA) and plantaris (PL) muscles during cat locomotion, and (2) to test the assumption that the force and activity patterns of soleus (SO), GA, and PL are mechanically and physiologically advantageous for providing the transfer of energy between these joints. The direction, amount and rate of the energy transfer through a two-joint muscle were defined using a theoretical analysis of movements in two adjacent joints spanned by the two-joint muscle. The energy transferred between the ankle and the knee was calculated using the time integration of the difference between the power developed by the moments of SO, GA, and PL at the ankle joint and the total power of these muscles. The total power of SO, GA, and PL muscles, and the power of their movements about the ankle and knee, were obtained using the experimentally determined muscle forces, the rates of change in muscle length, and the angular velocities at the knee and ankle which were calculated from the kinematics and the geometry of the cat hindlimb. Muscular forces and hindlimb kinematics of the cats were recorded during normal walking and trotting on a treadmill at speeds of 0.4, 0.8, 1.2, 1.5, and 1.8 ms-1 using 'E'-shaped tendon transducers and high-speed video, respectively. It was found that during the early phase of support, there was a transfer of mechanical energy from the ankle to the knee through GA and PL. During the late phase of support, mechanical energy was transferred from the knee to the ankle. The amount of energy transferred increased with increasing speeds of locomotion. The energy transferred from the ankle to the knee was 3-60 mJ (7-22% of the negative work done by the moments of SO, GA, and PL at the ankle), and the energy transferred from the knee to the ankle was 10-67 mJ (7-14% of the positive work done by the moments of SO, GA, and PL at the ankle). The results of this study suggest that the activation and the forces of one-joint SO and multi-joint GA and PL are organized in such a way as to fit the features of the design of these ankle extensor muscles in order to provide locomotion efficiently. For example, the decrease in the contractile abilities of SO during the late phase of support at fast speeds of locomotion may be compensated for by the transfer of energy from the knee to the ankle through GA and PL. The design of GA and PL (a high percentage of fast-twitch muscle fibers, large angles of pinnation and short length of the fibers, long tendons, and the location about the ankle and knee joints) seems to be well suited for transferring mechanical energy between the ankle and knee at fast speeds of locomotion. Because of the design of GA and PL, their contractile abilities remain close to the maximum at fast speeds of locomotion. The design of GA and PL allows for extension of the ankle joint through the action of the knee extensor muscles during knee extension with a relatively small change in length of GA and PL.
OBJECTIVE: To critically review the current data concerning the efficacy of preventive measures described in the literature, on the incidence of lateral ankle ligament injuries. DATA SOURCES: MEDLINE, Sportdiscus, and EMBASE were searched for papers published between 1980 and December 1998. Keywords used in the search were "prevention" in combination with "ankle," "ankle taping," "ankle bracing," "orthosis," "shoes," and "proprioception." Additional references were reviewed from the bibliographies of the retrieved articles. STUDY SELECTION: A study was included if: 1) the study contained research questions regarding the prevention of lateral ankle ligament injuries; 2) the study was a randomized controlled trial, a controlled trail, or a time intervention; 3) the results of the study contained incidence rates of lateral ankle ligament injuries as study outcome; and 4) the study met the cut-off score set for quality. DATA EXTRACTION AND SYNTHESIS: Two reviewers reviewed relevant studies for strengths and weaknesses in design and methodology, according to a standardized set of predefined criteria. Eight relevant studies met the criteria for inclusion and were analyzed. MAIN RESULTS: Overall, all studies reported a significant decrease in incidence of ankle sprains using the studied preventive measure. There was a great variety in methodology and study design between the eight analyzed studies, and every study had one or more drawbacks. Therefore, between studies only general results could be compared. CONCLUSIONS: The use of either tape or braces reduces the incidence of ankle sprains. Next to this preventive effect, the use of tape or braces results in less severe ankle sprains. However, braces seem to be more effective in preventing ankle sprains than tape. It is not clear which athletes are to benefit more from the use of preventive measures: those with or those without previous ankle sprains. The efficacy of shoes in preventing ankle sprains is unclear. It is likely the newness of the footwear plays a more important role than shoe height in preventing ankle sprains. Proprioceptive training reduces the incidence of ankle sprains in athletes with recurrent ankle sprains to the same level as subjects without any history of ankle sprains.