The influence of altered lower-limb muscle strength on dynamic plantar pressure distribution in participants who underwent anterior cruciate ligament reconstruction

Introduction Deficits in lower-limb muscle strength and altered gait mechanics are common after anterior cruciate ligament reconstruction (ACL). While isokinetic strength testing is widely accepted in return-to-sport assessment, the role of plantar pressure analysis in detecting compensatory gait strategies remains underexplored. Methods This study included 10 male patients (30.27 ± 5.59 years; 178.37 ± 6.30 cm; 84.85 ± 10.74 kg) who underwent ACL reconstruction using bone–patellar tendon–bone autografts. Assessments were performed preoperatively and at 3 and 6 months postoperatively, evaluating isokinetic knee strength and plantar pressure distribution during barefoot level walking. Non-parametric Friedman tests with Kendall's W assessed temporal differences, followed by Conover post hoc tests with Bonferroni correction. Spearman's rank correlation examined associations between muscle strength and plantar pressure. Results Significant deficits in extensor strength were found at both postoperative time points compared to preoperative levels (both p < .001), with improvement at six months vs. three ( p < .001). Flexor strength showed a similar but less pronounced recovery ( p = .005). Plantar pressure analysis revealed changes relative to baseline: reduced hindfoot contact area at six months ( p = .035), decreased midfoot maximum force at three ( p = .047) and six months ( p = .026), and lower peak pressure under the fifth metatarsal head at six months ( p = .035). No significant correlations emerged between muscle strength and plantar pressure parameters. Discussion These findings suggest plantar pressure analysis may complement return-to-sport evaluation by revealing hindfoot asymmetries persisting despite strength recovery. However, as dynamic plantar pressure parameters do not reflect quadriceps or hamstring status reliably, they cannot replace standard tests like isokinetic dynamometry. Combining plantar pressure metrics with conventional strength and functional assessments may better identify residual gait deficits and guide targeted rehabilitation to lower reinjury risk

Anterior cruciate ligament · Barefoot · Gait · Gait analysis · Heel · Physical medicine and rehabilitation · Plantar pressure · Pressure sensor · Knee injuries and reconstruction techniques · Lower Extremity Biomechanics and Pathologies · Medicine · Sports injuries and prevention · Anatomy · Orthodontics