Characteristics and predictors of muscle strength deficit in mechanical ankle instability

Abstract

Purpose Muscle strength training is a common strategy for treating chronic ankle instability (CAI), but the effectiveness decreases for mechanical ankle instability (MAI) patients with initial severe ligament injuries. The purpose of this study was to investigate the characteristics and the potential predictors of muscle strength deficit in MAI patients, with a view to proposing a more targeted muscle strength training strategy. Methods A total of 220 MAI patients with confirmed initial lateral ankle ligament rupture and a postinjury duration of more than 6 months were included. All patients underwent a Biodex isokinetic examination of the ankle joints of both the affected and unaffected sides. Then, the associations between the limb symmetry index (LSI) (mean peak torque of the injury side divided by that of the healthy side) and the patients’ sex, body mass index, postinjury duration, presence of intra-articular osteochondral lesions, presence of osteophytes and ligament injury pattern (i.e., isolated anterior talofibular ligament (ATFL) injury or combined with calcaneofibular ligament injury) were analysed. Results There was significantly weaker muscle strength on the affected side than on the unaffected side in all directions (p < 0.05). The LSI in plantar flexion was significantly lower than that in dorsiflexion at 60°/s (0.87 vs 0.98, p < 0.001). A lower LSI in eversion was significantly correlated with female sex (0.82 vs 0.94, p = 0.016) and isolated ATFL injury (0.86 vs 0.95, p = 0.012). No other factors were found to be associated with muscle strength deficits. Conclusion MAI patients showed significant muscle strength deficits on the affected side, especially in plantar flexion. There were greater strength deficits in eversion in females and individuals with an isolated ATFL injury. Thus, a muscle strength training programme for MAI patients was proposed that focused more on plantar flexion training and eversion training for females and those with an isolated ATFL injury.

Arthroscopic modified Broström procedure achieves faster return to sports than open procedure for chronic ankle instability

“…Isokinetic strength was assessed with a Biodex isokinetic dynamometer [14] (Biodex Medical Systems Inc, Shirley, NY). Aydoğ [2] found that isokinetic ankle strength measured by the Biodex were reliable (intraclass correlation coefficient ranged from 0.87 to 0.96).…”

New Values of Normal Ankle Strength and Its Importance for Rehabilitation and Return to Play

“…In the present study, the participants were seated, with the knee exed at approximately 20°, with the evaluated leg parallel to the ground. Different angular velocity protocols are also possible, with most research reporting velocities between 30-180°/s [42][43][44]. An inversely proportional trend describes the concentric mode's torque force and angular velocity relationship [45].…”

One in Three Patients With Chronic Lateral Ankle Instability Has a Cartilage Lesion

“…Blank cells indicate not available . BMI, body mass index; CLAI, chronic lateral ankle instability. b Hou et al 17 defined postinjury duration as the period from initial injury to examination. All other studies defined postinjury duration as the period from initial injury to surgery. c Kim et al 19 was the only study from which the percentage was calculated out of the number of ankles with CLAI, instead of the number of patients with CLAI. d The primary outcome was obtained by contacting the authors; therefore, no additional patient characteristics were available. e Data in parentheses indicate 95% CI. …”

“…With regard to the MINORS score, consensus was reached between the reviewers in all studies. Six noncomparative studies 5,8,17,27,28,46 had an average score of 8.8 out of 16 points (range, [7][8][9][10][11]. Six comparative studies [18][19][20]23,32,38 scored an average of 17 out of 24 points (range, [15][16][17][18][19].…”

“…Six noncomparative studies 5,8,17,27,28,46 had an average score of 8.8 out of 16 points (range, [7][8][9][10][11]. Six comparative studies [18][19][20]23,32,38 scored an average of 17 out of 24 points (range, [15][16][17][18][19]. The MINORS score per study is provided in the Appendix Table A2 (available online).…”