Preventive lateral ligament tester (PLLT): a novel method to evaluate mechanical properties of lateral ankle joint ligaments in the intact ankle.

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.

Early functional outcome of two different orthotic concepts in ankle sprains: a randomized controlled trial.

INTRODUCTION: Purpose of the study was the evaluation of the early functional outcome of patients with an acute ankle sprain treated either with a semirigid, variable, phase-adapted modular ankle orthosis or an invariable orthotic reference device. MATERIALS AND METHODS: Forty-seven patients with acute ankle sprain grade II or more were included. In addition, 77 healthy controls as a reference were investigated. The injured subjects were treated with one of the two devices by random for 6 weeks. Ankle scores (FAOS, AOFAS) were taken at baseline after injury, 1 and 3 months after injury. Functional performance tests (balance platform, zig zag run, shuttle run, vertical drop jump) were performed at 1 and 3 months after injury. RESULTS: No significant score differences could be found between the two intervention groups except for achieving a preinjury activity level after 3 months only in the modular orthosis group. Postural functional performances (balance test) also showed no significant differences whereas the results of the agility tests revealed small but significant better results in the modular orthosis group in comparison to the invariable orthosis group. Cohen's effect sizes were high. CONCLUSION: Differences between the two intervention groups were marginal and very small but significant and--regarding Cohen's effect sizes--effective. Especially relating to functional performance, this might be a careful indication that a more effective strategy for promoting a protected, rapid recovery to physical activity after ankle sprains might be achieved by applying a phase-adapted ankle orthosis. Especially in athletic patients, phase-adapted orthosis should be further investigated and considered to ensure fully protected ligament healing as well as to regain early functional recovery.

Residual mechanical effectiveness of external ankle tape before and after competitive professional soccer performance.

OBJECTIVE: To evaluate the presupposed preventive residual mechanical effectiveness of the widespread use of adhesive elastic ankle tape after a nonlaboratory, realistic soccer-specific outfield intervention reflecting a soccer halftime. DESIGN: A prospective nonrandomized test-retest design was used. SETTING: Laboratory. PARTICIPANTS: Seventeen professional male outfield players (mean age, 25.5) without any signs of chronic ankle instability. INTERVENTION: Participants were investigated before and after a 45-minute soccer-specific field intervention. MAIN OUTCOME MEASURES: The passive inversion range of motion (ROM) of the ankle was tested unloaded on a self-developed inversion device with and without a standardized ankle tape before and after the intervention. Additionally, electromyography signal was taken to assure the inactivity of the protective evertor muscles, and reliability tests for the inversion device (test-retest and trial to trial) were conducted in 12 healthy controls. RESULTS: Tape restricted the maximum passive inversion ROM of the uninjured ankle significantly to 50.3%. The protection declined nearly completely after 45 minutes of outfield soccer performance to a negligible nonsignificant ROM restriction of 9.7%. Pearson correlation coefficient for the reliability was 0.931 (P ≤ 0.001) for the test-retest and 0.983 (P ≤ 0.001) for the trial-to-trial test. CONCLUSIONS: The initial significant protection of external ankle-tape support declines almost completely without relevant remaining residual mechanical effect after 45 minutes, reflecting a soccer halftime. The so far presupposed residual mechanical effectiveness of tape to prevent injury is increasingly irrelevant during soccer performance and consequently antidromic to the increasing injury risk toward the end of a soccer halftime.

Short-term effects of a dedicated knee orthosis on knee adduction moment, pain, and function in patients with osteoarthritis.

OBJECTIVE: To analyze knee joint loading, subjective pain relief, and improvements in function in patients with osteoarthritis (OA) with the use of 2 orthosis adjustments. DESIGN: Patients were tested under 3 different conditions (without orthosis, orthosis at 4° valgus, and a neutral very flexible adjustment) in a crossover trial. SETTING: University gait analysis laboratory with 3-dimensional motion analysis and force platforms. PARTICIPANTS: Patients (N=11) with a clinical and radiographic diagnosis of unilateral OA in the medial knee compartment. INTERVENTIONS: Patients wore a knee orthosis designed to unload the medial knee compartment for 4 weeks in 2 different adjustments (2 weeks in each adjustment). MAIN OUTCOME MEASURES: Net knee adduction moment and net knee adduction angular impulse during the stance phase were analyzed by using inverse dynamics. Subjective pain relief, stiffness, and function improvement were evaluated using a questionnaire (Western Ontario and McMaster Universities Osteoarthritis Index). A 6-minute walk test and stair-climbing test also were performed. RESULTS: Both orthosis adjustments induced subjective pain relief and improvement in function compared with the condition without orthosis. Knee adduction moment was significantly decreased with both adjustments, whereas the decrease observed with the 4° valgus adjustment was significantly greater than the flexible adjustment (25% vs 12.5%). Compared with the condition without orthosis, changes in knee adduction angular impulse of 29% and 15% were found with 4° valgus and the neutral flexible orthosis, respectively. Time required for the stair-climbing activity was significantly decreased using the orthosis in 4° valgus adjustment compared with the condition without orthosis. No significant differences were observed among conditions during the 6-minute walk test. CONCLUSIONS: Both orthosis adjustments were effective in decreasing symptoms; however, a decrease in knee loading was more effective using the 4° valgus adjustment, which could contribute to avoidance of disease progression.