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At least 487 records · Page 27Linked to original sources
PubMed2002

Differences between trunk sway characteristics on a foam support surface and on the Equitest ankle-sway-referenced support surface.

Clinicians have sought ways to increase trunk sway so that it is easily observed and a balance deficit more easily identified. One technique often used for this purpose is to reduce the efficacy of ankle proprioceptive inputs on sway. To achieve this reduction either a foam mat is used as an unstable support surface or the subject stands on a surface made unstable with servo-driven ankle-sway-referencing. The purpose of the current study was to investigate differences in trunk pitch and roll sway characteristics using these techniques. Trunk sway while standing quietly on two legs was measured in 25 normal subjects in the age range 20-35 years for three support-surface conditions. Each condition was tested twice for 20 s, once with eyes open and once with eyes closed. The three conditions were standing on a foam support surface, standing on a support surface with pitch (fore-aft) ankle-sway-referencing as used for the standard Sensory Organization Test (SOT) of the Neurocom Equitest System (SOT 4 and 5), and standing with roll (lateral) ankle-sway-referencing. The latter was achieved by having the subjects stand turned 90 degrees to the standard SOT position. Two angular velocity sensors mounted on a belt measured trunk sway in the pitch and roll directions. Trunk roll angle and angular velocity amplitudes for pitch sway-referencing were reduced compared to either the foam or roll sway-referencing conditions, but trunk pitch angle and angular velocities amplitudes were greater. For roll sway-referencing, the trunk roll angle was greater than for the other stimulus conditions. Analyses of the trunk sway velocity in the frequency domain indicated that ankle-sway-referencing in the pitch direction increased trunk pitch sway at 1 Hz and decreased trunk roll sway between 2 and 5 Hz compared to foam support frequency spectra. Roll ankle-sway-referencing decreased trunk roll between 2 and 4 Hz only. These results indicate that using a foam support surface provides multidirectional trunk sway with velocity content across all frequencies in the range 0.8-5.2 Hz. Roll ankle-sway-referencing, but not pitch ankle-sway-referencing, yields trunk sway with similar characteristics to those with foam. Pitch ankle-sway-referencing forces pitch trunk resonance to be around 1 Hz and yields very different trunk sway from that obtained with a foam support surface. Roll sway-referencing is an alternative means to test multidirectional control of sway. Clinically though, foam is simpler to use and provides a more difficult balance task for the patient.

Adult↗
PubMed2003

Comparison of the catabolic effects of fibronectin fragments in human knee and ankle cartilages.

OBJECTIVE: To compare the response of knee and ankle cartilages to fibronectin fragments (Fn-f) in terms of kinetics of matrix proteoglycan (PG) degradation and synthesis, since previous data had shown that knee was more sensitive to Fn-f in terms of steady-state PG content. DESIGN: Human knee and ankle cartilage explants were treated with the 29kDa Fn-f, and its effects on PG-degradation kinetics, on the half-lives of 35S-sulfate-labeled PG, on PG synthesis suppression and on matrix metalloproteinase -3 (MMP-3) were compared. Cultures were also treated with the interleukin (IL) receptor antagonist protein (IRAP) in order to determine whether IL-1 is involved in the Fn-f effect. RESULTS: The Fn-f enhanced PG-degradation rates in both human knee and ankle cartilages. Knee cartilage showed a greater effect of Fn-f on half-lives of newly synthesized 35S-labeled PG than ankle. The extent of release of MMP-3 was similar for human ankle and knee cartilages. However, PG synthesis in knee cartilage was sensitive to 10- to 100-fold lower concentrations of Fn-f than was ankle cartilage. IRAP partially reversed Fn-f activity in ankle cartilages. CONCLUSIONS: The role of Fn-f in proteolysis leading to cartilage damage appears to be minor in human cartilages than had previously been shown for bovine. This decreased proteolysis is true for both knee and ankle. The major difference between human ankle and knee cartilage appears to be greater sensitivity to PG synthesis suppression in knee cartilage. A further indication that IL-1 is involved in the pathway was provided by the partial reversal with IRAP.

Adolescent↗
PubMedDate not supplied

Sprained ankle syndrome: prevalence and analysis of 639 acute injuries.

The ankle sprain is often thought of as an injury involving only the lateral ankle ligaments. Frequently other structures are also injured. However, the literature describes only some of the associated injuries. The authors feel that a thorough analysis of each structure injured with the inversion and eversion ankle sprain along with the incidence would be invaluable in making an accurate diagnosis and providing appropriate treatment. The authors conducted a prospective study using a standardized evaluation during the initial examination of patients reporting with an ankle sprain. Over a 33-month period, 639 patients were studied at Oakwood Hospital Downriver Center Emergency Room and Occupational Medicine Clinic. Of the 639 patients, 92 had an associated avulsion or compression fracture of the foot or ankle. Of the remaining 547 patients, the anterior talofibular ligament was injured 453 times, the calcaneal fibular ligament was injured 366 times, and the posterior talofibular ligament was injured 187 times. Injuries to the ankle joint capsule were noted in 180 cases, the extensor digitorum brevis was involved in 111 cases, the sinus tarsi was involved in 88 cases, the peroneal tendons in 83 cases, the Achilles tendon in 67 cases, the calcaneal-cuboid ligament in 41 cases, and the syndesmosis was injured in 31 cases. Additionally, neuritis was seen in 80 patients presenting with a sprained ankle. Because of the varied and multiple components to the common sprained ankle, the authors feel that this condition would more appropriately be designated as the sprained ankle syndrome. The findings of this study may aid the examiner in exploring a more knowledgeable approach in evaluation, leading to an accurate diagnosis and appropriate treatment.

Acute Disease↗
PubMed1996

Ankle blood pressure measurement, an acceptable alternative to arm measurements.

The use of automatic noninvasive blood pressure (NIBP) devices has become a common technique to monitor blood pressure intraoperatively. The usual cuff placement for these devices on the upper arm sometimes poses problems. As an alternative, many clinicians place the cuff on the ankle. This practice has not been previously investigated to determine its efficacy. The purpose of our study was to determine whether a noninvasive blood pressure cuff on the arm could be replaced by one on the ankle. We monitored 24 patients intraoperatively with two non-invasive blood pressure cuffs, one on the upper arm and one on the ankle. Systolic, diastolic, and mean pressures were obtained from each cuff placement at intervals of no shorter than 3 minutes. The time necessary to obtain the measurements and the presence of any artifact were also recorded. A total of 404 pairs of data were obtained and the systolic blood pressure ranged from 82 to 196 mm Hg. The mean and diastolic pressure readings were equivalent between the arm and ankle blood pressure readings. The systolic pressures were not equivalent, reflecting the fact that the ankle systolic blood pressure is physiologically higher than the arm systolic blood pressure. The difference between the times necessary to obtain the readings from arm or ankle was not statistically significant. Eight of the paired readings (2.0%) represented artifact, arbitrarily defined as a difference in mean blood pressure readings of 15 mm Hg between the arm and the ankle. Since the mean blood pressure readings obtained at the arm and at the ankle were statistically equivalent, we concluded that the ankle cuff placement provided a reliable alternative to the placement of the cuff on the arm.

Adult↗
PubMed1998

Serum sialic acid and ankle versus brachial arterial-pressure ratio in NIDDM.

Serum sialic acid is related to mortality from cardiovascular disease and is increased in patients with diabetic microangiopathies. The purpose of this study was to examine whether serum sialic acid is associated with ischemic disease of the lower extremities, using the ankle versus brachial arterial-pressure ratio. The subjects were NIDDM patients attending diabetic clinics. They received a questionnaire on smoking and duration of diabetes, and physical examinations including measurement of blood pressure of upper and lower extremities. Fasting blood was taken for measurement of sialic acid, total and HDL cholesterol, and HbA1c. Serum sialic acid was significantly correlated with ankle versus brachial arterial-pressure ratio (r = -0.32) and HbA1c (r=0.45). The correlation with ankle versus brachial arterial-pressure ratio was evident in the patients with low ankle versus brachial arterial-pressure ratios (r = -0.66), but was not significant in those with normal ankle versus brachial arterial-pressure ratios (r=0.16). The correlation with HbA1c was significant independently of ankle versus brachial arterial-pressure ratios. Mean serum sialic acid was higher in patients with very low ankle versus brachial arterial-pressure ratios (< 0.9) than in those with normal ankle versus brachial arterial-pressure ratios (> or = 1.0) or slightly low ankle versus brachial arterial-pressure ratios (0.9 approximately 1.0). These results suggest that serum sialic acid reflects the status of blood glucose control and the progression of ischemic disease of the lower extremities in NIDDM patients.

Ankle↗
PubMed1999

Ankle sprains and other soft tissue injuries.

Lateral ankle sprains are the most frequently encountered injuries in sports. In the evaluation of lateral ankle injury, one should consider all soft tissue structures (i.e., peroneal tendons, ligaments of the ankle, subtalar joints, around the lateral ankle). The treatment of most ankle sprains has evolved from immobilization to functional rehabilitation. Many patients with ankle sprains return to their previous activities. A few patients are left with pain and residual instability after conservative treatment; thus, the question of when to operate on acute severe ankle sprain remains controversial. The other challenge physicians face is the problem of persistent lateral ankle pain after sprain. This condition may be due to intra-articular or extra-articular pathology (i.e., soft tissue lateral ankle impingement, osteochondral lesion, or partial peroneal tendon tear). Diagnosis can be made with careful history, physical examination, and appropriate ancillary studies. Only proper diagnosis can lead to uncompromised, undelayed patient care.

Ankle Injuries↗
PubMed1998

Ankle arthrodesis in patients with rheumatoid arthritis.

The results of 26 ankle arthrodeses performed for rheumatoid arthritis on 21 patients were reviewed. Tibiotalar arthrodesis was performed in 14 ankles, and tibiotalocalcaneal arthrodesis was performed in 12. External fixation was used in 20 ankles, and internal fixation was used in six. Followup was available in 24 of 26 ankles (19 patients), and averaged 5 years (range, 2-8 years). There was no pain experienced in 19 ankles; mild, occasional pain was experienced in four ankles; and moderate, daily pain was experienced in one ankle. Daily activities were limited in five patients and recreational activities were limited in 11. All patients reported some difficulty walking on uneven terrain. Nearly all patients were satisfied; two were satisfied with reservations and two were dissatisfied. Union was achieved in 25 of 26 (96%) ankles. Ankle arthrodesis is an effective operation in patients with rheumatoid arthritis. Unlike previous reports, union and complication rates in this series were comparable with rates for arthrodesis for posttraumatic and degenerative arthritis.

Adult↗
PubMed1998

Charcot neuroarthropathy of the foot and ankle.

The goal of this study was to characterize Charcot neuroarthropathy of the foot and ankle by specific sites of involvement (ankle, hindfoot, midfoot, and forefoot), modes of presentation, methods of management, and outcome. A summary of treatment and results for 50 ankles, 22 hindfeet, 131 midfeet, and 18 forefeet is presented. Nondisplaced neuropathic ankle fractures typically healed uneventfully with casting and bracing. For displaced ankle fractures, closed reduction and casting generally resulted in loss of reduction and progressive deterioration; better results were obtained with open reduction and internal fixation, using supplemental Kirschner wires and screws. Ankles with Charcot neuroarthropathy and preexisting arthritis typically required arthrodesis. Of the ankles with neuropathic avascular talar necrosis, approximately 1/3 did well with nonoperative intervention and 2/3 required surgery. Chronic, unstable, malaligned Charcot ankles often required arthrodesis. Neuropathic calcaneal fractures were managed successfully nonoperatively. For feet with transverse tarsal joint involvement (Schon Type IV), management was more complex. Nonoperative treatment was successful for less than 1/2. Two thirds of the feet with midtarsus involvement (Schon Types I, II, and III) were managed successfully nonoperatively; 1/3 required surgery for recurrent ulceration, instability, or osteomyelitis. Half of the feet with forefoot neuroarthropathy required surgery for malalignment, ulceration, and/or difficulty with shoewear or braces. This review has established patterns of Charcot involvement of the foot and ankle with corresponding methods of treatment and subsequent responses. From this extensive clinical experience with 221 neuropathic fractures or Charcot joints, recommendations were derived to assist in selecting appropriate management options.

Ankle Joint↗
PubMed2001

Complications of total ankle replacement.

Total ankle arthroplasty is emerging as a viable treatment for patients with symptomatic tibiotalar arthritis who have not responded to nonoperative treatment. First generation ankle replacement prostheses had significant complications, leading many orthopaedic surgeons to abandon their use. Second generation designs have attempted to address some of these problems with innovative new designs. Ankle arthritis differs from other forms of degenerative arthritis in that the majority is posttraumatic in origin, and occurs in a younger age group. Correction of alignment is complicated by deformity of the foot distal to the ankle. Published results of second generation ankle replacement systems are limited, and the understanding of them is necessarily anecdotal. In the current study, complications of current second generation total ankle arthroplasty are divided into preoperative or patient selection problems, complications related to prosthetic design, intraoperative, and postoperative complications. Solutions, or the controversies surrounding those complications that have no obvious solution, will be discussed when appropriate. Total ankle arthroplasty with these second generation prostheses is gaining increasing popularity. The surgeon contemplating total ankle arthroplasty should have an understanding of anatomy and lower extremity biomechanics, and a thorough knowledge of the total ankle system he or she decided to use.

Ankle Joint↗
PubMed2006

The ability of the Lauge-Hansen classification to predict ligament injury and mechanism in ankle fractures: an MRI study.

OBJECTIVES: The Lauge-Hansen classification system was designed to predict the mechanism and ligament injury patterns of ankle fractures on the basis of x-rays. The purpose of this study was to evaluate the accuracy of these predicted injury sequences using magnetic resonance imaging (MRI) in a series of patients with ankle fractures. DESIGN: Retrospective cohort. SETTING: Two university level 1 trauma centers. PATIENTS: Fifty-nine patients with operative ankle fractures who were evaluated with both x-ray and MRI were included. INTERVENTION: All patients had a standard 3-view ankle x-ray series before fracture reduction, followed by an MRI. All plain x-rays were assigned to a Lauge-Hansen category by an experienced orthopedic traumatologist. MRI studies were subsequently read by an MRI musculoskeletal radiologist for the integrity of the ankle ligaments. MAIN OUTCOME MEASUREMENTS: After evaluation of the x-rays, fractures were classified according to the system of Lauge-Hansen, and the predicted presence, sequence, and mechanism of injury was determined. These were then compared to the actual injured structures on MRI in each case, and the ability of the Lauge-Hansen system to accurately predict the complete injury pattern was determined for the entire cohort. RESULTS: Average patient age was 59 (range: 18 to 84) years. Of the 59 ankle fractures evaluated, 37 (63%) were classified as supination external rotation, 11 (19%) were pronation external rotation, 1 (2%) was supination adduction, and 10 (17%) were not classifiable on the basis of the Lauge-Hansen system. Of the 49 fractures that fit into Lauge-Hansen categories, 26 (53%) had patterns of ligamentous injury and fracture morphology that did not coincide with the Lauge-Hansen predictions. A common fracture pattern was observed in 8 of the 10 unclassifiable fractures, which included a high spiral fracture of the fibula, vertical shear fracture of the medial malleolus, posterior malleolar fracture, and complete tears of the anterior-inferior tibiofibular ligament and the interosseous membrane. In addition, over 65% of patients in this series had complete ligamentous injury and a fracture of the malleolus to which the ligament attaches. CONCLUSIONS: These results demonstrate that the Lauge-Hansen classification system may have some limitations as a predictor of the mechanism of injury and the presence of soft-tissue damage associated with ankle fractures. The identification of a novel pattern of ankle fracture also illustrates how the system fails to describe all possible fracture patterns. For these reasons, we recommend that the Lauge-Hansen system be used only as a guide in the diagnosis and management of ankle fractures and not solely relied upon for treatment decisions. Although the exact clinical implications of the variety of ligamentous injuries observed on MRI are yet to be determined, this technique may be useful in individual cases in which doubt about joint stability and soft-tissue integrity exists. Additionally, MRI may be helpful in planning surgical approaches in atypical fractures in which injury patterns are less predictable solely on the basis of x-ray.

Adolescent↗
PubMed1998

Ground reaction forces and EMG activity with ankle bracing during inversion stress.

PURPOSE: The purpose of this investigation was to evaluate the effects of external ankle support on ground reaction forces and myoelectrical activity of selected lower extremity muscles during dynamic inversion stress. METHODS: Twenty-four healthy males performed five trials of a lateral dynamic movement at a rate between 80-90% of their maximal speed under three ankle brace conditions (no brace--control, Aircast Sport-Stirrup, Active Ankle). Ground reaction forces along the mediolateral axis and EMG activity of the peroneus longus, tibialis anterior, and medial gastrocnemius were simultaneously recorded during force plate contact. RESULTS: Ankle bracing did not affect peak impact force (P > 0.05), maximum loading force (P > 0.05), or peak propulsion force (P > 0.05) in the lateral direction compared with the control condition. Ankle bracing reduced the EMG activity of the peroneus longus during peak impact force compared with the control condition (P < 0.05), although no differences were noted between the two braces. Furthermore, peroneous longus activity during maximum loading force and peak propulsion remained unaffected (P < 0.05). Ankle bracing did not affect the EMG activity of the tibialis anterior and medial gastrocnemius at the point of peak impact force, maximum loading force (P > 0.05), and peak propulsion force (P > 0.05). CONCLUSIONS: These data suggest that ankle bracing may not affect the forces experienced at the foot and ankle, but helps reduce the strain placed on the peroneus longus during peak impact force. Furthermore, ankle bracing does not alter the function of the tibialis anterior and medial gastrocnemius during dynamic inversion stress.

Adult↗
PubMed2003

Evaluation of the Ottawa ankle rules in children.

OBJECTIVE: The Ottawa Ankle Rules (OAR) are criteria for predicting ankle fractures in adults allowing for insignificant fractures, defined as small avulsion fractures. Because the clinical significance of avulsion fractures and Salter-Harris type I fractures in children is unclear, we sought to prospectively evaluate the use of the OAR in children and to determine whether different criteria should be used for predicting ankle fractures in children. METHODS: In this prospective study, patients younger than 18 years presenting to a pediatric emergency department (ED) with an acute nonpenetrating ankle injury were eligible for study participation. Information on 22 clinical variables was recorded on a standardized data sheet. The OAR were included but not specifically identified on the data sheets. A standard ankle radiographic series was obtained on all subjects. All fractures were considered to be significant. Follow-up phone calls were performed to assess final diagnosis and outcome. Sensitivity and specificity of OAR and other potential criteria for predicting ankle fractures in children were calculated. RESULTS: A total of 195 patients with ankle injuries were evaluated. The mean age of patients was 12.6 years. Forty fractures (21%) were identified. The sensitivity of OAR was 83% (95% CI, 65-94%), specificity was 50% (95% CI, 41-59%), positive predictive value was 28%, and negative predictive value was 93%. Three independent factors were significantly associated with ankle fractures: inability to walk immediately after the event, inability to bear weight for four steps in the ED, and tender deltoid ligament. If one or more of these factors were present, sensitivity for predicting ankle fractures was 93% (95% CI, 78-99%), specificity was 27% (95% CI, 20-36%), positive predictive value was 23%, and negative predictive value was 95%. CONCLUSION: The OAR cannot be applied to children with the same sensitivity as adults.

Adolescent↗
PubMed2004

Ankle arthroplasties generate wear particles similar to knee arthroplasties.

Second-generation total ankle arthroplasties have encouraging medium-term results, but the wear of the joint materials is of concern. The aim of the current study was to examine and compare the size, shape, and concentration of polyethylene particles in synovial fluid with total ankle arthroplasties and established posterior-stabilized total knee arthroplasties. Synovial fluid was obtained from 15 patients with well-functioning total ankle arthroplasties and 11 patients with posterior-stabilized total knee arthroplasties at least 6 months after surgery. Polyethylene particles were isolated and analyzed using scanning electron microscopy. Particle size (equivalent circle diameter) in ankles was 0.81 +/- 0.09 microm (mean +/- standard error) and in knees was 0.78 +/- 0.08 microm. Particle shape (aspect ratio) in ankles was 1.57 +/- 0.04 and in knees was 2.30 +/- 0.22. The particle concentration was 1.02 +/- 0.43 x 10/mL in ankles and 1.13 +/- 0.56 x 10/mL in knees, and the particle concentration and size in total ankle arthroplasties were similar to those in total knee arthroplasties. Total ankle arthroplasties generated significantly rounder particles than total knee arthroplasties. These data suggest that the long-term result of total ankle arthroplasty should be as good as posterior-stabilized total knee arthroplasties in terms of polyethylene wear and the prevalence of osteolysis.

Aged↗
PubMed2004

Radiographic and biomechanical support for fibular plating of the agility total ankle.

Syndesmosis nonunion with the Agility total ankle system has been associated with adverse radiographic findings such as radiolucency and migration. We analyzed radiographs and biomechanical data to determine whether the addition of a fibular plate was associated with improved findings related to syndesmosis union compared with results when two syndesmosis screws alone were used. Radiographs for 40 consecutive ankles with the Agility total ankle system with two syndesmosis screws were compared with radiographs for the subsequent 40 consecutive total ankle replacements with an added fibular plate. When all ankles were considered, syndesmosis nonconsolidation at 6-10 weeks was associated significantly with nonunion at 5-7 months. Syndesmosis nonconsolidation at 6-10 weeks in ankles with screws alone was significantly higher than in ankles with plates. The radiolucency rate at 5-7 months also was significantly higher in ankles with screws alone than in ankles with plates. In the biomechanical evaluation using full tibia and fibula sawbones, maximum compression force within the syndesmosis was measured using the ISCAN sensor (TekScan). The addition of the fibular plate allowed significantly higher compression than the use of screws alone.

Adult↗
PubMed2006

Angiosomes of the foot and ankle and clinical implications for limb salvage: reconstruction, incisions, and revascularization.

BACKGROUND: Ian Taylor introduced the angiosome concept, separating the body into distinct three-dimensional blocks of tissue fed by source arteries. Understanding the angiosomes of the foot and ankle and the interaction among their source arteries is clinically useful in surgery of the foot and ankle, especially in the presence of peripheral vascular disease. METHODS: In 50 cadaver dissections of the lower extremity, arteries were injected with methyl methacrylate in different colors and dissected. Preoperatively, each reconstructive patient's vascular anatomy was routinely analyzed using a Doppler instrument and the results were evaluated. RESULTS: There are six angiosomes of the foot and ankle originating from the three main arteries and their branches to the foot and ankle. The three branches of the posterior tibial artery each supply distinct portions of the plantar foot. The two branches of the peroneal artery supply the anterolateral portion of the ankle and rear foot. The anterior tibial artery supplies the anterior ankle, and its continuation, the dorsalis pedis artery, supplies the dorsum of the foot. Blood flow to the foot and ankle is redundant, because the three major arteries feeding the foot have multiple arterial-arterial connections. By selectively performing a Doppler examination of these connections, it is possible to quickly map the existing vascular tree and the direction of flow. CONCLUSIONS: Detailed knowledge of the vascular anatomy of the foot and ankle allows the plastic surgeon to plan vascularly sound reconstructions, the foot and ankle surgeon to design safe exposures of the underlying skeleton, and the vascular surgeon to choose the most effective revascularization for a given wound.

Ankle↗
PubMed2007

Passive dorsiflexion flexibility after cast immobilization for ankle fracture.

Ankle fracture is frequently managed with cast immobilization, but immobilization may produce ankle contracture (loss of flexibility). We aimed to quantify recovery of ankle dorsiflexion flexibility in people treated with cast immobilization after ankle fracture, and to determine if initial orthopaedic management was associated with recovery. Ankle flexibility was measured in 150 people with plantarflexion contracture who had been referred for outpatient physical therapy following cast immobilization for ankle fracture. We obtained measurements using an instrumented footplate within 5 days of cast removal and then 4 weeks and 3 months later. Data were compared with published normative data. Both stiffness and the torque corresponding to the peak dorsiflexion angle at baseline decreased during the 3 month recovery period, but recovery was still incomplete 3 months after cast removal. Surgical fixation was associated with higher stiffness, preload and torque values. Passive ankle flexibility does not return to normal values within 3 months of cast removal after ankle fracture. Recovery of normal ankle dorsiflexion flexibility typically takes longer than the initial period of immobilization.

Ankle Injuries↗
PubMed2001

Human balancing of an inverted pendulum: is sway size controlled by ankle impedance?

Using the ankle musculature, subjects balanced a large inverted pendulum. The equilibrium of the pendulum is unstable and quasi-regular sway was observed like that in quiet standing. Two main questions were addressed. Can subjects systematically change sway size in response to instruction and availability of visual feedback? If so, do subjects decrease sway size by increasing ankle impedance or by some alternative mechanism? The position of the pendulum, the torque generated at each ankle and the soleus and tibialis anterior EMG were recorded. Results showed that subjects could significantly reduce the mean sway size of the pendulum by giving full attention to that goal. With visual feedback sway size could be minimised significantly more than without visual feedback. In changing sway size, the frequency of the sways was not changed. Results also revealed that ankle impedance and muscle co-contraction were not significantly changed when the sway size was decreased. As the ankle impedance and sway frequency do not change when the sway size is decreased, this implies no change in ankle stiffness or viscosity. Increasing ankle impedance, stiffness or viscosity are not the only methods by which sway size could be reduced. A reduction in torque noise or torque inaccuracy via a predictive process which provides active damping could reduce sway size without changing ankle impedance and is plausible given the data. Such a strategy involving motion recognition and generation of an accurate motor response may require higher levels of control than changing ankle impedance by altering reflex or feedforward gain.

Adolescent↗
PubMed1999

Early mobilization versus immobilization after ankle ligament stabilization.

Functional outcome, stability at radiographic investigation and ankle joint torque after anatomical reconstruction of the lateral ankle ligaments were evaluated in patients with early postoperative mobilization versus those with cast immobilization. Thirty patients with chronic lateral ligament instability of the ankle underwent anatomical reconstruction of the ligaments. Postoperatively the patients were randomly allocated to two groups: Group A (n=15) were immobilized in a below-knee plaster for 6 weeks and Group B (n=15) underwent early controlled range of motion training using an Air-Cast ankle brace. The functional results were evaluated using a scoring scale and objective results using standardized stress radiographs. Also eccentric and concentric muscle torque at 60 degrees/s was measured in plantar flexion and dorsiflexion, respectively. The functional results were satisfactory in 12/15 ankles in Group A and 14/15 in Group B (n.s.). All the patients with satisfactory results regained normal range of motion. Patients with unsatisfactory results had either residual pain or recurrent instability. In Group B, the strength measurements revealed significantly higher peak torque values after three months in plantar flexion at 60 degrees/s. Six months postoperatively, the torque values did not differ significantly between the groups. Also, there was no group difference in the laxity of the ankle joint, including both anterior talar translation test and talar tilt test, at the two-year follow-up. One patient had a superficial wound infection. We conclude that after the reconstruction of chronic lateral ligament instability of the ankle the functional and stability results were equally good with early postoperative mobilization and 6-week immobilization. However, using early mobilization plantar flexion strength was regained earlier than with cast immobilization, without any risk of short- or medium-term complications, such as increased ankle laxity. We recommend early mobilization after anatomical reconstruction of the lateral ankle ligaments.

Adolescent↗