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Purpose: To investigate the clinical measures of foot posture and morphology, multisegmented joint motion and play, strength, and dynamic balance in recreationally active young adults with and without a history of a lateral ankle sprain (LAS), copers, and chronic ankle instability (CAI)., Methods: Eighty recreationally active individuals (healthy: n = 22, coper: n = 21, LAS: n = 17, CAI: n = 20) were included. Foot posture index (FPI), morphologic measures, joint motion (weight-bearing dorsiflexion (WBDF), rearfoot dorsiflexion, plantar flexion, inversion, eversion; forefoot inversion, eversion; hallux flexion, extension), joint play (proximal and distal tibiofibular; talocrural and subtalar, forefoot; 1st tarsometatarsal and metatarsophalangeal), strength (dorsiflexion, plantar flexion, inversion, eversion, hallux flexion, lesser toe flexion), and Star Excursion Balance Test (SEBT) (anterior, posteromedial, posterolateral) were assessed., Results: There were no group differences in FPI or morphological measures. LAS and CAI groups had decreased ankle dorsiflexion (p = 0.001) and greater frontal plane motion (p < 0.001), first MT plantar flexion, and sagittal excursion (p < 0.001); increased talocrural glide (p = 0.02) and internal rotation (p < 0.001) and decreased forefoot inversion joint play (p < 0.001); and decreased strength in all measures (p < 0.001) except dorsiflexion compared to healthy controls. The LAS group also demonstrated decreased distal tibiofibular (p = 0.04) and forefoot general laxity (p = 0.05) and SEBT performance (anterior: p = 0.02; posteromedial: p < 0.001; posterolateral: p < 0.001)., Conclusion: Individuals with LAS or CAI have increased pain, impaired physiologic and accessory joint motion, ligamentous tenderness, and strength in the foot and ankle. Clinicians should assess the multiple segments of the ankle-foot complex when caring for individuals with an LAS or CAI., Level of Evidence: II.

Purpose: To compare muscle strength, muscle endurance, and postural stability in both the affected and unaffected ankles between patients with chronic ankle instability (CAI) who underwent conservative treatment and those who underwent the modified Broström procedure (MBP)., Methods: A total of 67 patients (37, conservative treatment; 30, MBP) participated. Muscle strength and muscle endurance were measured using an isokinetic device, and postural stability was tested using a postural stabilometry system. We used the independent t test for continuous variables with a normal distribution and Fisher's exact test for categorical variables., Results: There was no difference in the muscle strengths of the affected and unaffected ankles between the groups. The muscle endurance of plantarflexion and inversion muscles was significantly lower in the affected ankles of the conservative treatment group than in those of the MBP group (plantarflexion: 209 ± 103.1 vs. 318 ± 162.2, p = 0.001; inversion: 93 ± 58.7 vs. 154 ± 65.9, p < 0.001). Static postural stability testing showed no significant differences between the affected and unaffected ankles of the two groups. In the dynamic postural stability test, the overall, anterior-posterior, and medial-lateral stability indices were all significantly higher in the affected ankles of the conservative treatment group than in those of the MBP group (p < 0.001, p = 0.004, p = 0.004, respectively), with no differences observed in the unaffected ankles., Conclusion: The MBP may significantly improve muscle endurance and dynamic postural stability in CAI patients in whom conservative treatment has failed. Therefore, clinicians should consider using MBP instead of conservative treatment when patients show severe muscle weakness or dynamic postural instability., Level of Evidence: Case-control study, Level III.

Purpose: To compare the surgical outcomes of the two different ankle stabilization techniques., Methods: This randomized controlled trial aimed to compare the outcomes of the modified Broström procedure with [calcaneofibular ligament (CFL) group] or without CFL repair [anterior talofibular ligament (ATFL) only group]. Of the 50 patients randomly assigned to two groups, 43 were followed up prospectively for ≥ 2 years (CFL group: 22 patients, 36.6 ± 13.1 months; ATFL Only group: 21 patients, 35.3 ± 11.9 months). Functional outcomes were assessed using the Karlsson-Peterson and Tegner activity level scoring systems. Anterior talar translation (ATT), talar tilt angle (TTA), and degrees of displacement of the calcaneus against the talus on stress radiographs were measured. All parameters were compared between the two groups. Multiple regression analysis setting the postoperative Karlsson-Peterson score as the dependent variable was performed to determine the significant variable., Results: There were no significant differences between the two groups in functional (Karlsson-Peterson and Tegner activity level) scores at the last follow-up and their changes. There were no significant differences between the two groups in the ATT, TTA, their differences compared with the contralateral ankles, and degrees of displacement of the calcaneus against the talus at the last follow-up. Osteochondral lesion of the talus rather than CFL repair was the significant variable related to functional outcome., Conclusion: The modified Broström procedure with additional CFL repair did not result in a significant advantage in any measured outcome at 3 years., Level of Evidence: Randomized controlled trial, Level I.

Purpose: To compare proprioception, postural stability, and neuromuscular control between patients with mechanical laxity and recurrent ankle sprain., Methods: Among 86 patients with ankle instability, 45 patients had mechanical laxity (mean age 27.2 ± 7.0 years) and 41 had recurrent ankle sprain (mean age 25.1 ± 9.2 years). Both the affected and unaffected ankles of each patient were evaluated. Proprioception and neuromuscular control tests were conducted using an isokinetic machine, and postural stability was tested using a postural stabilometry system., Results: Proprioception was not significantly different between the unaffected or affected ankles of the mechanical laxity group compared with those of the recurrent ankle sprain group (n.s). Static and dynamic postural stability and neuromuscular control were similar in the affected ankles between the two groups (n.s). However, postural stability (static, overall: p = 0.009, anterior-posterior: p = 0.028, medial-lateral: p = 0.022; dynamic, overall: p = 0.012, anterior-posterior: p = 0.004, medial-lateral: p = 0.001) and neuromuscular control (inversion: p = 0.031, eversion: p = 0.039, dorsiflexion: p = 0.029, plantarflexion: p = 0.035) were significantly decreased in the unaffected ankles of the recurrent ankle sprain group compared with those of the mechanical laxity group., Conclusion: The unaffected ankles of the recurrent ankle sprain group showed significant decreases in both postural stability and neuromuscular control compared with the mechanical laxity group. Clinicians and therapists should consider unaffected ankle rehabilitation in patients with recurrent ankle sprain to prevent future sprain events., Level of Evidence: Case-control study, III.

Purpose: The purpose of this study was to investigate the effect of chronic ankle instability (CAI) on electromechanical delay times (EMD) before and after fatigue. Understanding the mechanisms that contribute to CAI is essential for the development of effective rehabilitation programmes. It was hypothesized that patients with CAI will demonstrate prolonged EMD times compared to healthy subjects and that fatigue will cause greater increases in EMD times in the CAI group., Methods: Twenty-one male volunteers participated in the study providing data on 16 ankles with CAI and 26 with no history of ankle injury. EMD was measured on an isokinetic dynamometer. Measurements were taken with the ankle in neutral (0°) and at 30° of inversion. All subjects followed an isokinetic fatigue protocol until eversion torque fell below 50 % of initial torque for three consecutive repetitions. A 2 × 2 × 2 ANOVA was used to calculate the effect of ankle status (CAI vs. healthy), fatigue, angle (0° vs. 30°) and their interactions on EMD., Results: Fatigue caused a significant increase on EMD [non-fatigued: 122(29)ms vs. fatigue 155(54)ms; p < 0.001]. EMD times were shorter at 30° of inversion compared to neutral [neutral: 145(39)ms vs. 30° of inversion: 132(40)ms, p = 0.015]. An interaction effect for ankle status and angle was found (p = 0.026) with CAI ankles demonstrating longer EMD [CAI: 156(45)ms vs. healthy: 133(40)ms] in neutral but not at 30° of inversion [CAI: 133(46)ms vs. 132(33)ms]., Conclusions: Patients with CAI had longer EMD times in neutral, but not when the ankle was placed in inversion. This suggests that rehabilitation programmes may be more effective when retraining occurs with the ankle in neutral position. It is likely that low EMD times prevent ankle acceleration at the beginning of the mechanism of injury, but they are less important when the ankle has already inverted at 30°. Both CAI and healthy subjects demonstrated longer EMD after fatigue, emphasizing the importance of proper conditioning in the prevention of delayed peroneal response and subsequent ankle injury. Improving resistance to fatigue of the peroneals may prove to be an effective prevention tool of ankle sprain recurrence in patients with CAI., Level of Evidence: III.

Purpose: Balancing unicondylar knee arthroplasty (UKA) is challenging. If not performed properly, it may lead to implant loosening or progression of osteoarthritis in the preserved compartment. This study was aimed to document the biomechanical effects of improper balancing. We hypothesised that overstuffing would lead to more valgus, higher strain in the medial collateral ligament (sMCL), and higher lateral contact force., Methods: Six fresh-frozen cadaver specimens were mounted in a kinematic rig. Three motion patterns were applied with the native knee and following medial UKA (passive motion, open-chain extension, and squatting), while infrared cameras recorded the trajectories of markers attached to femur and tibia. Three inlay thicknesses were tested (8, 9, 10 mm)., Results: Overstuffed knees were in more valgus and showed less tibial rotation and higher strains in the sMCL (p < 0.05). Lateral contact forces were higher in some specimens and lower in others. Stiffening of the medial compartment by UKA, even well balanced, already leads to a knee more in valgus with a more stressed sMCL. Overstuffing increases these effects. Knees with a tight sMCL may even see lower lateral contact force. Biomechanics were closest to the native knee with understuffing., Conclusion: The first two hypotheses were confirmed, but not the latter. This underlines the importance of optimal balancing. Overstuffing should certainly be avoided. Although kinematics is only slightly affected, contact forces and ligament strains are considerably changed and this might be of more clinical importance. It is advisable to use thinner inlays, if stability is not compromised.

Purpose: A painful episode in the region of the peroneal tendons, within the retromalleolar groove, is a common precipitating event of an acute lateral ankle sprain. A forefoot striking pattern is suspected to cause peroneal tendinosis. The aim of this study is to analyse the role of peroneal tendinosis as a predisposing factor for ankle sprain trauma in runners., Methods: Fifty-eight runners who had experienced acute ankle sprain trauma, with pre-existing pain episodes for up to 4 weeks in the region of the peroneal tendons, were assessed clinically. Fractures were excluded by conventional radiography. An magnetic resonance imaging (MRI) scan had been performed within 14 days after the traumatic event and was subsequently evaluated by two experienced radiologists., Results: MRI revealed peroneal tendinosis in 55 patients (95% of the total study population). Peroneus brevis (PB) tendinosis was found in 48 patients (87% of all patients with peroneal tendinosis), and peroneus longus (PL) tendinosis was observed in 42 cases (76%). Thirty-five patients (64%) had combined PB and PL tendinosis. A lesion of the anterior talofibular ligament was found to be the most common ligament injury associated with peroneal tendinosis (29 cases; 53%), followed by a lesion of the calcaneofibular ligament (16 cases; 29%) and a lesion of the posterior tibiofibular ligament (13 cases; 24%)., Conclusion: The results of this study reflect the correlation between peroneal tendinosis and ankle sprain trauma. Injuries of one or more ligaments are associated with further complications. A period of rest or forbearance of sports as well as adequate treatment of the peroneal tendinosis is essential to prevent subsequent ankle injuries, especially in runners. Modification of the running technique would also be beneficial., Level of Evidence: IV.

Purpose: To construct and evaluate an ankle arthrometer that registers inversion joint deflection at standardized inversion loads and that, moreover, allows conclusions about the mechanical strain of intact ankle joint ligaments at these loads., Methods: Twelve healthy ankles and 12 lower limb cadaver specimens were tested in a self-developed measuring device monitoring passive ankle inversion movement (Inv-ROM) at standardized application of inversion loads of 5, 10 and 15 N. To adjust in vivo and in vitro conditions, the muscular inactivity of the evertor muscles was assured by EMG in vivo. Preliminary, test-retest and trial-to-trial reliabilities were tested in vivo. To detect lateral ligament strain, the cadaveric calcaneofibular ligament was instrumented with a buckle transducer. After post-test harvesting of the ligament with its bony attachments, previously obtained resistance strain gauge results were then transferred to tensile loads, mounting the specimens with their buckle transducers into a hydraulic material testing machine., Results: ICC reliability considering the Inv-ROM and torsional stiffness varied between 0.80 and 0.90. Inv-ROM ranged from 15.3° (±7.3°) at 5 N to 28.3° (±7.6) at 15 N. The different tests revealed a CFL tensile load of 31.9 (±14.0) N at 5 N, 51.0 (±15.8) at 10 N and 75.4 (±21.3) N at 15 N inversion load., Conclusions: A highly reliable arthrometer was constructed allowing not only the accurate detection of passive joint deflections at standardized inversion loads but also reveals some objective conclusions of the intact CFL properties in correlation with the individual inversion deflections. The detection of individual joint deflections at predefined loads in correlation with the knowledge of tensile ligament loads in the future could enable more individual preventive measures, e.g., in high-level athletes.

Purpose: Currently, controversy exists whether restoration of neutral mechanical alignment should be attempted in all patients undergoing TKA. Our hypothesis was that restoration of constitutional rather than neutral mechanical alignment may in theory lead to a more physiological strain pattern in the collateral ligaments; therefore, it could potentially be beneficial to patients. Thus, the aim of this study was to measure collateral ligament strains during three motor tasks in the native knee and compare them with the strains noted after TKA in different post-operative alignment conditions., Methods: Six cadaver specimens (approval number ML4190 from the Research Ethics Committee of University of Leuven, Belgium) were examined using a validated knee kinematics rig under physiological loading conditions. The effect of coronal malalignment was evaluated by using custom-made tibial implant inserts that induced different alignment conditions. The study of six specimens allows us to show that a difference in the mean strains in MCL and LCL of 3.6 and 5.8 %, respectively, was statistically significant with a probability (power) of 0.8., Results: The results indicated that after TKA insertion, the strains in the collateral ligaments closely resembled the pre-operative pattern of the native knee specimens when constitutional alignment was restored. Restoration to neutral mechanical alignment was associated with greater collateral strain deviations from the native knee., Conclusion: Based upon this study, it was concluded that restoration of constitutional alignment within a "safe zone" of ±2° during TKA leads to more physiological peri-articular soft tissue strains during loaded as well as unloaded motor tasks.

Purpose: To demonstrate the potential for a simple clinical test of hamstring muscle strength to identify susceptibility to muscle strain injury., Methods: A single-case design was used; specifically, an elite-level male Australian Rules football player performed bilateral isometric maximum voluntary contractions of the hamstring muscles on a weekly basis for a period of 5 weeks preceding a right hamstring muscle strain injury., Results: Minimal asymmetry (no greater than ±1.2% difference) was evident in the hamstring isometric maximum voluntary contractions during the first 4 weeks, but 5 days prior to injury, the right hamstring isometric maximum voluntary contraction was reduced by 10.9% compared to the left., Conclusion: Measuring asymmetry in isometric maximum voluntary contractions of the hamstring muscles may be a useful clinical test to identify susceptibility to muscle strain injury.

The purpose of this study was to investigate the effects of isokinetic exercise on strength, joint position sense and functionality in recreational athletes with functional ankle instability (FAI). Strength, proprioception and balance of 24 recreational athletes with unilateral FAI were evaluated by using isokinetic muscle strength measurement, ankle joint position sense and one leg standing test. The functional ability was evaluated using five different tests. These were; single limb hopping course (SLHC), one legged and triple legged hop for distance (OLHD-TLHD), and six and cross six meter hop for time (SMHT-CSMHT). Isokinetic peak torque of the ankle invertor and evertor muscles were assessed eccentrically and concentrically at test speeds of 120 degrees /s. Isokinetic exercise protocol was carried out at an angular velocity of 120 degrees /s. The exercise session was repeated three times a week and lasted after 6 weeks. At baseline, concentric invertor strength was found to be significantly lower in the functionally unstable ankles compared to the opposite healthy ankles (p < 0.001). This difference was not present after executing the 6 weeks exercise sessions (p > 0.05). Ankle joint position sense in the injured ankles declined significantly from 2.35 +/- 1.16 to 1.33 +/- 0.62 degrees for 10 degrees of inversion angle (p < 0.001) and from 3.10 +/- 2.16 to 2.19 +/- 0.98 degrees for 20 degrees of inversion angle (p < 0.05) following the isokinetic exercise. One leg standing test score decreased significantly from 15.17 +/- 8.50 to 11.79 +/- 7.81 in the injured ankles (p < 0.001). Following the isokinetic exercise protocol, all of the worsened functional test scores in the injured ankles as compared to the opposite healthy ankles displayed a significant improvement (p < 0.01 for OLHD and CSMHT, p < 0.001 for SLHC, TLHD, and SMHT). These results substantiate the deficits of strength, proprioception, balance and functionality in recreational athletes with FAI. The isokinetic exercise program used in this study had a positive effect on these parameters.

Improvement of ankle proprioception through physiotherapy (a.k.a. proprioceptive training) is a widely accepted conservative treatment modality of chronic functional lateral ankle instability. Clinical studies provided controversial data on its proprioceptive effect. Aim of this study was to gain evidence on the efficacy of proprioceptive training on ankle joint position sense. Ten patients (five males and five females, aged 23.3+/-5.4 years) were treated conservatively for chronic lateral ankle instability with a special training programme over 6 weeks. For the assessment of joint position sense we used the slope-box test, first applied and described by Robbins et al. (Br J Sports Med 29:242-247, 1995). The test was performed before the start and after the end of the training programme, measuring joint position sense on 11 different slope amplitudes in four directions (anterior, posterior, lateral and medial) in random order each on both ankles. Comparisons were made between pre- and post-training results as well as versus a control-group of ten healthy athletes. Overall the proprioceptive sensory function of the studied group has improved, but this improvement was not significant in all directions. Only two patients have shown significant improvement of joint position sense in all directions (mean estimate error improvement: 2.47 degrees ), while conservative treatment was partially successful in five others (mean estimate error improvement: 0.73 degrees ). The follow-up results of these seven patients were comparable with the values measured in the control-group. Three patients did not show any improvements (mean estimate error improvement: -0.55 degrees ) (overall difference between improving and non-improving patients: P<0.0001). Mean absolute estimate error profiles of the seven improving patients became similar to the profiles of healthy athletes, while these changes could not be observed in the case of the three non-improving participants. Proprioceptive rehabilitation programme can be an effective method in order to improve impaired joint position sense function. After 6 weeks non-responding patients can be well identified, and considered for other treatment modalities. The determination of the effective length of the programme however needs further evaluation. Still, changes in the proprioceptive sensory function of the ankle plantarflectors indicate the preventive effect of the training programme. Furthermore, our results support the theory of simultaneous function of different mechanoreceptor-systems.

The purpose of this study was to analyse objective modalities of ankle joint function after an acute ankle sprain and to see whether treatment with an air-cushioned ankle brace could enhance the restoration of function compared with a traditionally used compression bandage. The study included 73 consecutive patients between 15 and 55 years of age with an acute grade II or III ankle sprain, who sought medical care within 24 h of the time of injury. Patients with recurrent sprain were excluded. The patients were allocated at random to treatment with compression bandage or an air-cushioned ankle brace (Air-Stirrup, Aircast). The regimen included early motion and weight-bearing in both groups. The patients were examined initially within 24 h, after 3-5 days, 2, 4 and 10 weeks after the injury by the following tests: clinical examination including range of motion, recording of postural sway by stabilometry, joint position sense test, isokinetic eversion-inversion muscle torques and figure-of-eight running. A decreased active range of motion in eversion-inversion was observed during the entire follow-up period. Increased postural sway was registered when standing on the injured foot up to 4 weeks after the injury, as were a deficit in evertor muscle peak torque and an evertor-invertor muscle imbalance compared with the uninjured side. Women demonstrated a greater impairment in postural sway than men. A longer curve running time with the injured ankle at the outside of the curve was noted at the 10-week follow-up. With the exception of running in a figure of eight, these measures were not influenced by treatment with a semi-rigid ankle brace. The methods used in the present study are well suited for further studies of objective modalities of ankle joint function, with the possible exception of the joint position sense test.

The application of adhesive tape to the ankle prevents sprains and is therefore frequently used by athletes with functional instability of that joint. The purpose of the study was to investigate the effect of taping on postural sway during a sudden perturbation in subjects with unilateral functional instability of the ankle joint. Nine Swedish male elite soccer players with unilateral functional instability of the ankle joint after a sprain participated in the study. Their mean age was 25 years. All but one had sustained an ankle sprain during the last 1-12 months, and they applied adhesive tape on one ankle at every practice session and game. Eight moderately active male subjects served as controls (mean age 32 years). Recording and analysis of postural sway was performed by the use of stabilometry. We used a device previously tested for reliability and added a perturbation device. The perturbation device was an ankle disc standing on four bars on top of the force plate. At the start of each recording, the ankle disc was stable. The bars could be removed simultaneously by the test leader. The following parameters were analysed: (1) max sway, the maximal sway amplitude upon perturbation in mediolateral and anteroposterior directions; (2) mean sway, the mean sway during the recording in mediolateral and anteroposterior directions. There was no difference between the right and left ankles before the practice session. The postural sway during perturbation (max sway) decreased when the ankle was taped before the exercise. After the exercise there was no difference between the taped and untaped ankles. The maximum and mean amplitude of sway without tape were smaller after exercise than before exercise. The results in the present study indicate a positive effect of tape on postural sway during perturbation before a practice session. The decreased sway with an untaped ankle after the practice session could mean that the prophylactic effect of taping is most important during the first part of a practice session or a game. Warmer muscle units mean less uncontrolled muscle activity which could result in more effective stabilisation of the ankle joint.

The ankle joints of 14 healthy volunteers and 16 patients with unstable ankle joints were tested regarding their functional and proprioceptive capabilities. All of them were active athletes. Three tests were used of the study: single-leg stance test, single-leg jumping course test, angle-reproduction test. The influence of three stabilization devices (lace-on-brace/"Mikros", stirrup-brace/"Aircast", taping) on the proprioceptivity of stable and unstable ankle joints was evaluated. The scores of the single-leg jumping course without any stabilizing device (category "standard") ranged between 8.06 and 13.68 (10.65 +/- 1.29). In the categories "Mikros" (9.85 +/- 0.99), and "Aircast" (9.99 +/- 1.14) as well as with the tape bandage (10.27 +/- 0.81) better scores were achieved. The differences "standard vs. Mikros" and "standard vs. Aircast" revealed a significant reduction of the scores with orthoses (P < 0.01). The error rate in the single-leg stance test was within the range of 0-16 (5.12 +/- 2.85) for the category "standard". It was lower for the categories "Mikros" (3.65 +/- 2.65) and "Aircast" (4.17 +/- 2.59). The error rate was highest in the group with a tape bandage (5.79 +/- 3.53). The differences "standard vs Mikros" as well as "standard vs. Aircast" were significant (P < 0.01). There was also a significant difference between these categories regarding injured and not injured ankle joints (P < 0.01). The angle-reproduction-test showed higher values for the category "standard" (2.36 degrees +/- 0.97) in comparison to the categories "Mikros" (1.46 degrees +/- 0.72), "Aircast" (1.62 degrees +/- 0.91) and "taping" (1.84 degrees +/- 0.41).(ABSTRACT TRUNCATED AT 250 WORDS)

The present study compares postural ankle stability between previously injured basketball players, uninjured players and a control/group. Postural sway was recorded and analysed by stabilometry using a specially designed computer-assisted forceplate. Recordings were obtained for 60 s on each foot. The stabilometric results in the players with no previous injuries did not differ from those in the controls. Players with a previously injured ankle differed significantly from the control group. These players had a larger mean postural sway and used a larger sway area.