AmirAli Jafarnezhadgero

Background Anterior cruciate ligament reconstruction (ACLR) is commonly performed to restore anatomical and functional knee stability. Although altered walking biomechanics have been observed post-ACLR, previous studies have not consistently accounted for the interval between injury and surgery. Objective This systematic review and meta-analysis aimed to determine whether walking-related knee biomechanical alterations following ACLR are transient or persist over time, and whether the timing of surgery influences these alterations. Methods Five electronic databases (Scopus, PubMed, Web of Science, Physiotherapy Evidence Database [PEDro], and Cochrane Central Register of Controlled Trials [CENTRAL]) were systematically searched from inception through August 2026. Studies comparing walking biomechanics between patients who underwent ACLR and healthy controls and reporting the interval between anterior cruciate ligament injury and reconstructive surgery were included. Biomechanical outcomes during the stance phase of walking were extracted and stratified according to the interval between injury and surgery: short term (0 to < 6 months), mid-term (6 to < 12 months), and long term (≥ 12 months). Standardized mean differences (SMDs) with 95% confidence intervals were calculated using a random-effects model. Study quality was assessed using a modified Downs and Black checklist. Results Of the 3522 identified records, 16 studies involving male and female participants aged 18–55 years met the inclusion criteria. The mean methodological quality score was 65%, indicating an overall moderate level of methodological quality. Compared with healthy controls, ACLR participants demonstrated lower peak knee flexion angle (SMD = − 0.33, 95% confidence interval [CI] − 0.64 to − 0.02, p = 0.03, I² = 57%), peak knee adduction angle (SMD = − 0.47, 95% CI − 0.92 to − 0.01, p = 0.04, I² = 66%), and peak knee flexion moment (SMD = − 0.64, 95% CI − 1.05 to − 0.23, p = 0.002, I² = 76%). In subgroup analyses, the long-term group (≥ 12 months between injury and surgery) demonstrated lower peak knee flexion angle (SMD = − 0.27, 95% CI − 0.54 to − 0.00, p = 0.05, I² = 8%) and peak knee flexion moment (SMD = − 1.97, 95% CI − 3.77 to − 0.17, p = 0.03, I² = 88%). The short-term group (0 to < 6 months) demonstrated lower peak knee adduction angle (SMD = − 0.79, 95% CI − 1.18 to − 0.40, p < 0.0001, I² = 19%) and peak knee extension moment (SMD = − 0.55, 95% CI − 0.93 to − 0.18, p = 0.004, I² = 50%). Conclusions The interval between anterior cruciate ligament injury and ACLR was associated with differences in postoperative walking biomechanics. Delayed reconstruction (≥ 12 months) is associated with persistent sagittal plane deficits, which may reflect chronic neuromuscular adaptations or preoperative joint degeneration. In contrast, early surgery (within 6 months after anterior cruciate ligament injury) was associated with fewer long-term sagittal-plane deficits, although temporary frontal-plane asymmetries and extension deficits may persist during the early postoperative period and may improve with rehabilitation. These findings underscore the importance of considering the timing of ACLR when planning surgery and postoperative rehabilitation to support walking recovery.

Objective This systematic review and meta-analysis aimed to examine the biomechanical characteristics of running in individuals who had undergone anterior cruciate ligament reconstruction (ACLR) at various postoperative time intervals. Methods A systematic search was performed in PubMed, Google Scholar, Scopus, SID, Magiran, ISC, ScienceDirect, JCR, and Web of Science from May ...

Individuals with anterior cruciate ligament reconstruction and pronated feet (ACLR-PF) often display abnormal running ground reaction forces (GRFs), which are associated with higher re-injury risk and post-traumatic osteoarthritis. While foot orthoses (FOs) are used to influence biomechanics, their effectiveness at various post-operative stages in this group remains unknown. This study aimed to evaluate the immediate impact of different FOs on GRFs during running in males with ACLR-PF at 6-, 12-, and 18-months post-operative, compared to a healthy control group. This controlled laboratory study with randomized repeated orthotic conditions included males with ACLR-PF at 6, 12, and 18-months post‑operative, as well as healthy controls. Forty-five right-footed males with ACLR-PF were divided into three groups based on post-operative duration: 6 ± 1 months (group A, n = 15), 12 ± 1 months (group B, n = 15), and 18 ± 1 months (group C, n = 15). A matched health control group (group D, n = 15) was also included. Participants ran at 3.2 m/s under four randomized footwear conditions: control shoe, placebo orthotic, double-density orthotic, and arch-support orthotic. Three-dimensional GRFs were collected using a force plate. ACLR-PF groups at 12- and 18-months showed significantly higher impact vertical peaks and vertical loading rates than the healthy group. The 6-months ACLR-PF group had a longer time-to-peak for the impact vertical peak. Peak positive free moment was higher in the 6- and 18-months ACLR-PF groups compared to controls. A significant main effect of FOs was detected, with the double-density orthotic significantly decreasing the peak positive free moment relative to the control shoe. Significant group-by-FOs interactions indicated that the impact of specific orthoses on peak posterior force, loading rate, and stance time depended on the post-operative stage. Abnormal loading patterns continue up to 18-months after ACLR in individuals with PF, highlighting a critical window for intervention. FOs, especially double-density designs, can immediately adjust specific maladaptive GRFs, such as lowering excessive rotational moments. An orthotic prescription should be customized to the individual's specific biomechanical deficits and the stage in the rehabilitation process. In this controlled laboratory study, double-density and arch-support FOs acutely modified selected GRFs in males with ACLR and PF across post-operative stages. These findings suggest that FOs may provide immediate biomechanical adjustments during running; however, the long‑term clinical relevance of these acute changes remains uncertain and requires longitudinal investigation.

This study examined how running-induced fatigue protocol affects ground reaction forces (GRFs) in individuals with anterior cruciate ligament reconstructio

Objective: Artificial intelligence has made a significant breakthrough with its ability to analyze complex data and identify hidden patterns, especially in the field of gait biomechanics. The aim of this study was to review and classify different AI approaches in gait biomechanics analysis. Methods: The present study was a systematic review. Searches ...

Background: In this systematic review with meta-analysis, we aimed to compare the kinematic and kinetic variables of the involved limb with the contralateral limb in individuals who had undergone an anterior cruciate ligament reconstruction (ACLR) recorded during walking from short-term (p < 0.0001, I² = 66%). More specifically, the peak knee flexion angle was 2.63° (95% CI −3.81 to −1.44) lower in the ACLR compared to the contralateral limb. The analysis of time post-surgery revealed significant differences in the short-term (four studies: large SMDs = −1.14, 95% CI −1.61 to −0.67, p < 0.00001, I² = 56%) and mid-term (five studies: small SMDs = −0.52, 95% CI −0.74 to −0.29, p < 0.0001, I² = 0%) periods after surgery but not for the long-term follow-up (10 studies: small SMDs = −0.10, 95% CI −0.27 to 0.07, p = 0.26, I² = 32%). Meta-analysis indicated that the peak knee flexion moment was significantly lower in the ACLR compared to the contralateral limb (11 studies: small SMDs = −0.37, 95% CI −0.59 to −0.14, p = 0.0001, I² = 46%). A lower peak knee flexion moment was observed in the ACLR limb for both less than 12 months (three studies: moderate SMDs = −0.76, 95% CI −1.44 to −0.07, p = 0.03, I² = 66%) and over 12 months (eight studies: small SMDs = −0.25, 95% CI −0.43 to −0.07, p = 0.01, I² = 46%) after surgery time points compared to the contralateral limb. Conclusion: These findings suggest a time-dependent compensatory mechanism, where protective adaptations (e.g., reduced flexion/extension moments) may initially offload the reconstructed limb, with some asymmetries resolving over time. Clinically, these results underscore the need for rehabilitation strategies tailored to address phase-specific deficits, promoting symmetrical loading and functional recovery.