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PubMed1995

[Effects of fibular malunion on contact area and stress distribution at the ankle with six simulated loading conditions].

A shortened, externally rotated malunion in the lateral malleolus following an ankle fracture-dislocation often causes post-traumatic degenerative arthrosis even without talar displacement (occult malunion). The purpose of this study was to examine the effect of malalignment of the fibula on stress distribution in the ankle joint using two grades of pressure sensitive film (super-low and low) as a transducer. The ankles of seven amputated lower legs were mounted in an MTS machine, then loaded in 6 different positions of 3 single leg stance positions at the neutral, abduction and adduction of the foot, and 3 simulated positions in the stance phase of walking. A normal ankle, an ankle with 5 mm shortened fibula only, and an ankle with a shortened fibula plus an additional 20 degrees external rotation of the fibula were tested. Talar shift was examined on X-ray, before and after each test. When the fibula was shortened, and after additional external rotation, there was no talar shift even after loading and the total contact area was not significantly different from normal, however, there was the stress increase on the lateral side of the tibio-talar joint, with the area of higher stress range significantly larger than normal. There was no significant difference between the ankle with a shortened fibula only and that with an additional 20 degrees external rotation. The stress change in the fibular malalignment was concluded to be mainly due to the shortened fibula. It seems that the shortened lateral malleoli affect the ankle joint regardless of the talar shift and may induce degenerative arthrosis.

Aged↗
PubMed1998

[Biomechanics of the ankle joint--injury mechanisms].

The complex mechanics of the ankle joint complex depends highly on the integrity of the ankle ligaments. An incomplete restoration of the antero-fibular ligament after trauma may result in a mechanical dissociation of the talus from the ankle mortise. The force that is needed to induce a non-physiological movement of the foot is determined by the individual configuration of the bony and articular structures of the hindfoot. A pes cavus is less protected to suffer of an ankle sprain than a flatfoot. As the leverarm of the peroneal muscles decreases with increasing plantarflexion of the foot, the active protection to resist against a supination stress decreases with plantarflexion. These findings have significant implications for the practice. First of all an adequate treatment of any ankle sprain is necessary to restore the mechanical interplay of the ankle joint complex. Ankle orthoses should protect the foot against supination stress and excessive plantarflexion. The prevention of ankle injury may be significantly improved by recognition of the individual mechanical disposition.

Ankle Injuries↗
PubMed1995

Decision rules for roentgenography of children with acute ankle injuries.

OBJECTIVE: The Ottawa Ankle Rules (OAR) assist emergency physicians in the appropriate use of roentgenography in adults with acute ankle injuries. The OAR state that ankle roentgenograms are needed only if there is pain near the malleoli and one or more of the following exists: (1) age 55 years or older; (2) inability to bear weight; or (3) bone tenderness at the posterior edge or tip of either malleolus. This study assessed the utility of the OAR on pediatric patients with acute ankle injuries. DESIGN: Prospective, consecutive survey of pediatric patients with acute ankle injuries. SETTING: Pediatric emergency department of an urban university hospital. PARTICIPANTS: Seventy-one children with acute ankle injuries were enrolled from July 22, 1993, to December 1, 1993. INTERVENTIONS: Twenty-four standardized clinical variables were assessed and recorded by physicians in the pediatric emergency department. The OAR were applied to each patient by the investigator to determine which ones would qualify for roentgenography. MAIN OUTCOME MEASURES: Sensitivity and specificity of the OAR were calculated, as was percent reduction in roentgenograms ordered. RESULTS: Seventy-one of 73 eligible patients were enrolled. The two missed patients had open fractures of the tibia. Sixty-eight of 71 patients had ankle roentgenography during the visit. Fourteen patients (21%) (mean age, 11.8 +/- 4.0 years) had fractures noted on the roentgenograms. Fifty-four patients (79%) (mean age, 12.0 +/- 3.6 years) had no fracture. Application of the OAR would have reduced the number of roentgenograms ordered by 25% without missing any fractures. Sensitivity of OAR was 100% (95% confidence interval, 77% to 100%), specificity was 32% (95% confidence interval, 21% to 43%), negative predictive value was 100% (95% confidence interval, 80% to 100%), and positive predictive value was 28% (95% confidence interval, 17% to 39%). CONCLUSIONS: Initial testing suggests that the OAR may help determine which children with acute ankle injuries could safely forgo roentgenograms without risk of missing fractures.

Acute Disease↗
PubMed1988

Effects of ankle taping on the motion and loading pattern of the foot for walking subjects.

Gait analysis was used to compare the ground reaction forces, ankle and foot rotations in the sagittal plane, and the center of pressure pattern beneath the right feet of seven normal subjects walking barefoot, with and without their right ankles taped in the neutral position. Instrumentation included a force plate, ankle goniometer, and two accelerometers mounted on top of the foot. The ground reaction forces showed no changes between the same ankle, taped and untaped. Taping served to reduce the range of ankle rotations in the sagittal plane by approximately 20%, with a subsequent increase in the rotation about the metatarsal heads during heel-up. Heel-up occurred earlier in stance when the ankle was taped than with no taping. The vertical force graph was integrated over time when the center of pressure was located beneath the heel and the ball, resulting in two impulse measurements. The heel impulse decreased for each of the 7 subjects and 6 of the 7 subjects displayed an increase in the ball impulse due to taping, indicating that taping served to shift the load-time history away from the heel and toward the ball. The results of this study may apply to fused ankle patients, who may suffer forefoot abnormalities subsequent to ankle fusion surgery.

Adult↗
PubMed1994

Technique for in vivo measurement of the three-dimensional kinematics and laxity characteristics of the ankle joint complex.

We introduce here a technique to measure the three-dimensional kinematics and laxity characteristics of the ankle joint complex in vivo. The system consists of an optoelectric, kinematic data acquisition system that is used to measure the motion of the ankle joint complex in response to controlled moments applied through a system of pneumatic actuators. As a first step toward development of the method into a quantitative diagnostic tool for injuries of ankle ligaments, we addressed the following questions: (a) What is the reliability for measurement of range of motion and laxity of the ankle joint complex? (b) Are there significant differences in laxity between the left and right joints of a healthy individual? and (c) Are there significant differences in laxity of the ankle joint complex between men and women? To answer these questions, we performed repeated measures of range of motion and laxity of paired ankles in a population of 18 healthy young individuals. The high intraclass correlation coefficients obtained from the statistical analysis indicate that the new experimental system is highly reliable in measurement of total range of motion and total laxity of the ankle joint complex. We further concluded that, within the statistical power available in our experimental design, there are no significant differences in either range of motion or laxity between left and right ankles of healthy individuals or between men and women.

Adult↗
PubMed2006

Changes in lower limb kinematics, kinetics, and muscle activity in subjects with functional instability of the ankle joint during a single leg drop jump.

The purpose of this study was to identify differences in 3D kinematics, kinetics, and ankle joint muscle activity in subjects with functional instability (FI) of the ankle joint during a drop jump. Twenty-four subjects with the subjective complaint of FI of the ankle joint and 24 noninjured control subjects performed 10 single leg drop jumps onto a force-plate. Timing and magnitude of kinetic data, timing of kinematic data, and integrated EMG (IEMG) activity of the rectus femoris, peroneus longus, tibialis anterior, and soleus muscles during two 200-ms time periods either side of initial contact (IC) with the ground were analyzed and compared between groups. Subjects with FI demonstrated a significant decrease in pre-IC peroneus longus IEMG activity, which was accompanied by a change in frontal plane movement at the ankle joint during the same time period. Following IC, FI subjects were less efficient than control group subjects in reaching the closed packed position of the ankle joint. Significant differences were seen between the groups' time-averaged and peak vertical and sagittal components of ground reaction force. The altered pre-IC peroneus longus IEMG and increased inversion of the ankle joint observed in FI subjects could help to explain why subjects with FI may suffer from inversion injury to their ankle joint when subjected to an unanticipated ground contact. The kinematic and kinetic differences observed in subjects with FI may lead to repeated injury and damage to the supporting structures of the ankle joint.

Adult↗
PubMed1993

Effect of upper tibial osteotomy on fibula movement and ankle joint motion.

Several techniques of upper tibial osteotomy in the treatment of unicompartmental osteoarthritis of the knee have been described. Osteotomy of the fibula is normally also carried out, or alternatively, dissection of the capsule of the proximal tibiofibular joint. There is concern, however, that this latter procedure may have an adverse effect on the mobility of the ankle joint and on fibula rotation. To investigate these suspected interactions we performed experimental studies in 14 cadaver legs. The vertical, lateral and rotational movements of the fibula were measured with the ankle in neutral (0 degrees) and maximal ankle dorsiflexion before and after performing an interligamental upper tibial osteotomy of a standardised valgus wedge. Maximal ankle dorsiflexion before the osteotomy produced external rotation of the fibula in most specimens, whereas after osteotomy this movement caused mainly internal rotation. In the neutral position of the ankle, upper tibial osteotomy lead to external rotation of the fibula. The upward movement of the fibula head after osteotomy was 0.64 cm on average. There was no measurable vertical motion of the fibula during ankle dorsiflexion either before nor after upper tibial osteotomy. Ankle dorsiflexion improved minimally after osteotomy. In conclusion, this study shows that upper tibial osteotomy with dissection of the capsule of the proximal tibiofibular joint has no adverse effect on movement of the fibula or of the ankle joint. In addition, unlike fibular osteotomy, this technique also has the advantage that the risk of common peroneal nerve injury is minimal.

Ankle Joint↗
PubMed2006

[Muscle biomechanics in total ankle replacement].

The purpose of this orthopaedic-biomechanical study was to evaluate the muscle function in total ankle replacement (TAR) patients 1 year after surgery. Ten patients underwent a combined clinical and muscle biomechanical assessment prior to implantation and at the 1-year follow-up. Pain score, American Orthopaedic Foot and Ankle Society (AOFAS) ankle score, ankle range of motion (ROM), and calf circumference difference between the affected leg and contralateral healthy leg were assessed. Biomechanically, isometric maximal voluntary torque for ankle dorsiflexion and plantar flexion was measured simultaneously with surface electromyography of four lower leg muscles. At follow-up, a significant improvement of the pain score (from 6.7 to 0.8 points), AOFAS ankle score (from 35.6 to 92.3 points), and ROM could be shown. Not significantly, the mean calf circumference difference between legs decreased from 2.2 to 1.4 cm. However, a significant increase was seen in the mean dorsiflexion (from 17.0 to 25.8 Nm) and plantar flexion torque (15.7 to 24.6 Nm) of the TAR-treated ankle. The mean EMG frequency content of the affected lower leg at TAR follow-up was lower than in the muscles of the contralateral healthy side. In contrast, the mean EMG intensity at TAR follow-up in side-comparison was statistically the same for all muscles. Ankle OA patients have better muscle function with TAR than under the arthritic condition, but they do not reach the normal level of the contralateral healthy leg 1 year after surgery.

Adult↗
PubMed2005

Stabilizing effects of ankle bracing under a combination of inversion and axial compression loading.

The combined effects of bracing, axial compression and inversion rotation on the ankle-subtalar complexes were evaluated. Ex vivo tests under the load-controlled condition were performed on six cadaver ankle specimens using a six degree-of-freedom fixture. Inversion rotation was measured while subjecting the ankle-subtalar complex to a 2.5 N-m inversion moment and a combination of the testing variables (brace type, no brace, 178 N axial compression load, no compression load, 0 degrees and 20 degrees of plantar flexion) for a total of 16 tests per specimen. Three commercially available braces (two semirigid types and one lace up type) were evaluated. An axial compression load significantly decreased ankle-subtalar motion in unbraced ankles for the tested inversion moment. The contribution of bracing to stabilization of the ankle was smaller in the axial loading condition than in the no axial loading condition. The semirigid braces had greater stabilizing effects in response to the inversion moment than the lace up brace. Stabilizing effects of bracing were significantly greater in 20 degrees of plantar flexion than in 0 degrees of plantar flexion. The most common mechanism for an ankle sprain injury is inversion rotation on a weight-bearing ankle. Therefore, we should not overestimate stabilizing effects of bracing from evaluations of bracing without axial compression loading.

Adult↗
PubMed1997

Influence of external stabilizing devices of the ankle on sport-specific capabilities.

We compared sport-specific-skills in 23 athletes with functionally unstable ankle joints to those of 18 healthy volunteers by performing a Japan test as well as a specially designed single-leg jumping test. For external stabilization of the ankle, an Aircast brace, a Ligafix Air brace, a Malleoloc brace and a tape bandage were applied. For the Japan test in the group with uninjured ankle joints, the best results were obtained when wearing the Aircast brace, followed by tape bandage, Ligafix brace and no stabilizing device in descending order. The worst results were presented by the group with the Malleoloc brace. However, there were no significant differences among these devices. In the group with functionally unstable ankle joints, the best score was achieved with the tape bandage, followed by the Ligafix brace, Mallcoloc brace and Aircast brace. The unstabilized group showed significantly worse results compared with all other groups. In the single-leg jumping test, the stabilizing devices had no negative influence on the jumping capability in the uninjured ankle joints. Additionally, there was no significant difference among the orthoses. Volunteers with unstable ankle joints experienced a significant improvement of jumping performance with most of the devices. The best results were achieved with the Aircast brace, followed by the Malleoloc brace, Ligafix brace and tape bandage. However, there was no significant difference among these orthoses. While the reaction time of the volunteers was the same for all test situations, the time for dynamically stabilizing the ankle joint appeared to be significantly worse in those ankle joints without a brace. For athletic activities, which are dominated by movement patterns comparable to the Japan test as well as the jumping test used, these stabilizing devices seem to have no negative effect on sport-specific capabilities.

Adult↗
PubMed2003

fMRI analysis of ankle movement tracking training in subject with stroke.

This study examined whether ankle-movement tracking training could improve ankle function and brain reorganization, evidenced with functional magnetic resonance imagery (fMRI), in a single subject with stroke. Test measurements included self-ratings of functional activities, 15.24 m (50 feet) walk time, ankle range of motion, ankle tracking accuracy, and peak dorsiflexion movement during dorsiflexion phases of tracking. Cortical activation in the frontal and parietal lobes was measured during fMRI with an active voxel count. Additionally, a signal intensity index was determined for the gyrus precentralis (GPrC). Training consisted of 16 sessions of tracking waveforms on a computer screen with ankle motion. Four pretest, four posttest and two follow-up measurements occurred. Data were analyzed by visual inspection and by statistical analysis that examined whether posttest measurements exceeded the pretest mean by at least two standard deviations on at least two consecutive posttest measurements. Posttest results showed that the subject's self report of paretic ankle "catches" (failure of toes to clear floor during swing phase) during gait were eliminated and that peak dorsiflexion movement improved visually but not statistically. Multiple cortical areas showed increased voxel count statistically, as did the intensity index for GPrC. Follow-up results showed that the ankle "catches", peak dorsiflexion movement, and the intensity index remained at the same levels as posttest. Voxel counts returned toward pretest values. We concluded that tracking training produced training effects in both ankle function and brain reorganization.

Ankle↗
PubMed2004

Navigation for ankle arthroscopy: anatomical study of the anterolateral portal with reference to the superficial peroneal nerve.

We aimed to navigate the surgeon regarding the localization of the main anatomical structures at the anterior part of the ankle joint, in order to find easily the safest anatomical points with reference to the superficial peroneal nerve (SPN), in particular for anterolateral portal placement in ankle arthroscopy. Sixty-three ankles in 36 fresh cadavers were dissected. In all specimens we examined (1) the distance between the SPN bifurcation and the most distal point of the lateral malleolus; and at the level of ankle joint, (2) the number of SPN, (3) the distance between the medial and intermediate dorsal cutaneous nerves, which are branches of the SPN, (4) the localization of the peroneus tertius (PT) tendon in relation to the lateral malleolus, (5) the width of the extensor digitorum longus (EDL) tendon, (6) the relationship of the PT tendon and (7) the relationship of the extensor hallucis longus (EHL) tendon with the SPN. The results were as follows: (1) In 41 ankles with bifurcation (65%) the average distance was 71.8+/-35.3 mm. (2) There were two SPN branches in 39 (62%), three branches in seven (11%) and one branch in 17 (27%) cases. (3) In 39 ankles with two branches of the SPN, the mean distance was 15.2+/-7.1 mm. (4) The lateral border of the PT tendon was positioned a mean distance of 20.8+/-3.3 mm proximal and 25.2+/-5.8 mm medial to the reference points. (5) The mean width was 10.1+/-2.9 mm. (6) In 42 ankles (67%) the distance between the lateral border of the PT tendon and the SPN was a mean of 6.2+/-6.6 mm, median of 3 mm (range 0-22 mm lateral to the tendon). (7) In 56 cases (89%) a branch of the SPN was found a mean of 6.6+/-4 mm and a median of 6 mm lateral to the EHL tendon, and in seven cases (11%) on the tendon. According to our study, in ankle arthroscopy the risk of the SPN injury is maximal in the 0-3 mm lateral to the PT tendon. To avoid injury to the SPN, the safest placement of the anterolateral portal is 4 mm lateral to the PT tendon.

Adult↗
PubMed2005

Efficacy of total ankle replacement with meniscal-bearing devices: a systematic review and meta-analysis.

INTRODUCTION: The reputation of total ankle arthroplasty for treating end-stage ankle arthritis of different origin is dubious. Newer generation meniscal-bearing prostheses may have overcome the known problems with earlier implants. There is, however, no systematic approach to the available scientific evidence allowing for a critical appraisal of their benefits and risks. MATERIALS AND METHODS: We conducted a systematic review meta-analysis of studies exploring the efficacy of three-component total ankle prostheses. We demanded a minimum sample size of 20 subjects, at least 1 year of follow-up, and a clinically relevant study endpoint (for example, results of ankle scoring, ranges of motion [ROM], complications, and survival rates). We identified citations by electronic medical databases and a manual search. We made no restrictions for language. We used an eight-point quality scale to appraise methodological standards, and modeled outcomes by random-effects meta-regression analysis. RESULTS: Eighteen of 1830 citations including 1086 patients fulfilled our eligibility criteria. Studies met a median of four quality items (interquartile range 2-5). Outcome estimates did not depend on methodological quality. There was no evidence of strong heterogeneity or publication bias. With standardized 100-point ankle and hindfoot scores, formal data pooling was possible for 10 trials (n =497), showing a mean improvement of 45.2 points (95% confidence interval [CI] 39.3-51.1). Overall ROM improved slightly (6.3 degrees, 95%CI 2.2-10.5 degrees ). Weighted complication rates ranged from 1.6% (deep infections) to 14.7% (impingement). Secondary surgery had to be performed in 12.5%, whereas secondary arthrodesis was necessary in 6.3%. The weighted 5-year prosthesis survival rate averaged 90.6%. CONCLUSIONS: Ankle arthroplasty improves pain and joint mobility in end-stage ankle arthritis. Its performance in comparison to the current reference standard (that is, ankle fusion) remains to be defined in a properly designed randomized trial.

Ankle Joint↗
PubMed1996

Foot-ankle injuries: influence of crash location, seating position and age.

Foot-ankle injuries have increased in relative importance in recent years. As a basis for future countermeasures, an epidemiology study has been undertaken using Swedish accident data from Folksam Insurance. The database consists of 805 foot-ankle injuries out of 57,949 car occupant injuries reported from 1985 to 1991. The influence of crash location, seating position and occupant age is determined for the frequency, incidence and rate of foot-ankle injury in car crashes. Frontal car crashes produce 76% of the AIS 2-3 foot-ankle injuries with 13% in side impacts and 8% in roll-overs. The rate of AIS 2-3 foot-ankle injury is 24.7 per 1000 occupants injured in all crash locations and is similar irrespective of seating positions. Ankle fractures and sprains both occur at an incidence of 3.7 per 1000 injuries, followed by malleolus fractures at 2.7 and midtarsal fractures at 2.4. The foot-ankle injury incidence and rate are significantly greater (p < 0.01) in near oblique-frontal crashes than for 12 o'clock frontals. For drivers in 11 o'clock and front passengers in 12 o'clock, the incidence is 27.8 per 1000 injuries as compared to 17.5 for drivers and front passengers in 12 o'clock crashes. Occupant age is not as significant as seating position and crash location; however, there are higher incidences for rear occupants > or = 60 years old in oblique frontal crashes. Using the new AAAM Impairment Injury Scale (IIS), 48% of the foot-ankle injuries are rated with residual impairment IIS 1-2. The incidence in near-seated occupants is 1.5 times greater in oblique frontal crashes than in frontals. The incidence for IIS 1-2 impairment in near oblique-frontal crashes is 12.8 per 1000 occupant injuries as compared to 8.3 in frontal crashes.

Abbreviated Injury Scale↗
PubMed1980

Inhibition of flexor burst generation by loading ankle extensor muscles in walking cats.

The role of proprioceptive input from the ankle extensor triceps surae in the control of walking was examined in premammillary cats walking on a treadmill. The left hindlimb was rigidly fixed in one position after denervating almost all the leg muscles except the ankle extensor (triceps surae) and ankle flexor (tibialis anterior). Rhythmic alternating contractions of the isolated ankle flexor and extensor occurred in the fixed hindleg during periods of walking in the other three intact limbs. These rhythmic contractions disappeared when the isolated triceps surae was stretched so as to increase the force of the active contractions to beyond 4 kg. With maintained stretch the periodic contractions in the ankle flexor and extensor returned only after the force in the stretched triceps surae gradually decreased and fell below approximately 4 kg. Isometric contractions of the triceps surae produced either by stimulation of ventral root S1 or by large amplitude vibrations also led to the sudden disappearance of ankle flexor bursts. Inhibition of the locomotory rhythm could also be produced in all muscles of a single intact hindleg by clamping the ankle joint in a flexed position so as to stretch the ankle extensor. In all these cases, an increased rate of stepping of the contralateral hindleg was associated with the inhibition of the rhythmic locomotory activity. It is suggested that triceps surae proprioceptors signalling the presence of loading of the hindlimb extensor muscles inhibit the central generation of hindlimb flexion. During normal walking this mechanism could be of major importance during stance to prevent the initiation of the swing phase of a time when hindlimb extension is fully needed to support the weight of the animal. Thus a necessary, but not always sufficient, condition for the initiation of swing may be an unloading of leg extensor muscles.

Animals↗
PubMed1991

Impaired venoarteriolar reflex as a possible cause for nifedipine-induced ankle oedema.

Ankle oedema is not an uncommon side effect of treatment with nifedipine. To evaluate the possible effect of nifedipine on the microcirculation of the skin, 18 patients with systemic hypertension who were known to develop ankle oedema after nifedipine and 19 patients with systemic hypertension who did not develop ankle oedema after nifedipine were studied. Following four weeks of nifedipine therapy (10 mg, three times daily), the microcirculation on the dorsum of the foot was measured using laser-Doppler flowmetry. Estimation of the microcapillary flow was made both after supine resting and on standing upright. The venoarteriolar reflex was expressed as the standing flow in percentage of the resting flow. There was no significant difference between the two groups of patients in the resting flow, supine flow, or the venoarteriolar reflex before nifedipine therapy (P greater than 0.4). Before nifedipine, the blood blow in the skin of both groups of patients was reduced from the supine level upon standing, thus indicating a normal response to dependency. After nifedipine administration, no significant difference was observed between the two groups of patients in the resting flow (P greater than 0.5). The flow on standing, however, was 96.2% of that measured during resting supine in patients who developed ankle oedema and 79.8% of the resting flow in the patients who did not develop ankle oedema, suggesting a weaker venoarteriolar reflex in patients who developed ankle oedema following administration of nifedipine (P less than 0.0001). Thus, the microcapillary flow did not decrease upon standing in patients who developed ankle oedema following nifedipine therapy, indicating an abnormal venoarteriolar reflex. This may explain why ankle oedema develops in such patients following nifedipine.

Adult↗
PubMed2004

Changes in ground reaction force during jump landing in subjects with functional instability of the ankle joint.

OBJECTIVE: To identify changes in ground reaction force during jump landing in subjects with functional instability of the ankle joint. DESIGN: Comparison of ground reaction force during jump landing between subjects with functional instability and healthy controls. BACKGROUND: We have recently demonstrated significantly altered patterns of ankle and knee movement immediately pre- and post-impact in subjects with functional instability compared to healthy controls. We now examine the changes in timing and magnitude of forces sustained by the unstable ankle during jump landing. METHODS: Fourteen subjects with unstable ankles and 10 age, sex and activity matched controls performed five single leg jumps onto a force platform whilst ground reaction forces were sampled. Timing and magnitudes of forces during the first 150 ms following impact were analysed and compared between groups. RESULTS: Lateral and anterior force peaks occurred significantly earlier in subjects with functional instability. Significant differences were seen between groups' time-averaged vertical, frontal and sagittal components of ground reaction force. These ranged from 5% (frontal force) to 100% (vertical force) of body mass. These changes occur immediately post-impact and too early for reflex correction/modification. CONCLUSIONS: The disordered force patterns observed in subjects with functional instability are likely to result in repeated injury due to significant increase in stress on ankle joint structures during jump landing. We suggest that they are most likely to result from deficits in feed-forward motor control. RELEVANCE: These results identify the potentially injurious nature of the changes in the forces applied to the unstable ankle joint during jump landing. The timing of these changes suggests that they are caused by a motor control deficit. Treatment approaches aimed at retraining feed-forward control of ankle joint movement could succeed in restoring more normal patterns of force absorption and reduce the occurrence of repeated micro-trauma to ankle structures.

Adaptation, Physiological↗
PubMed2006

Efficacy of intra-articular hyaluronic acid in patients with osteoarthritis of the ankle: a prospective study.

OBJECTIVE: To investigate the efficacy, safety and the duration of treatment effectiveness of intra-articular hyaluronic acid (Artz, Japan) in patients with ankle osteoarthritis (OA). METHOD: As a prospective clinical trial, 93 patients with unilateral ankle pain for at least 6 months and radiographically classified as Kellgren-Lawrence grade I or II ankle OA were included. After five weekly intra-articular Artz injections, the Ankle Osteoarthritis Scale (AOS), the American Orthopaedic Foot and Ankle Society (AOFAS) ankle/hindfoot score, ankle sagittal range of motion (ROM), patients' global satisfaction, local adverse events and consumption of rescue analgesics were analyzed. RESULTS: Seventy-five patients completed the study. Significant improvement in AOS and AOFAS ankle/hindfoot scores was noted at 1 week, 1 month, 3 months and 6 months post the fifth injection (P < 0.001 compared with baseline). The mean reduction of AOS score was 1.9, 2.6, 2.5 and 2.6 at each following visit (P < 0.001). The mean AOFAS ankle/hindfoot score improved from 64 points at baseline to 75, 78, 78, and 78 points at 1 week, 1 month, 3 months and 6 months, respectively, post the fifth injection (P < 0.001). Ankle sagittal ROM did not improve significantly (P > 0.05). The majority of patients reported satisfaction at 1 week (100%), 1 month (100%), 3 months (90.7%) and 6 months (86.7%) follow-up. Local adverse events occurred in 6.7% of patients. Acetaminophen consumption dropped significantly following treatment (P < 0.001). CONCLUSION: Five weekly intra-articular injections of Artz provide pain relief and functional improvements in patients with Kellgren-Lawrence grades I and II ankle OA. The clinical effect was rapid at 1 week and may last for 6 months or more.

Adjuvants, Immunologic↗