Knee Osteoarthritis Following Anterior Cruciate Ligament Reconstruction: Frequency, Contributory Elements, and Recent Interventions to Modify the Route of Degeneration

The evolution of three-dimensional knee kinematics after ACL reconstruction within one year

Introduction

This study aims to explore the dynamic changes in the six degrees of freedom (6DOF) kinematics of the knee joint in patients within one year after anterior cruciate ligament reconstruction (ACLR), combined with clinical scoring systems to analyze functional recovery characteristics, providing scientific evidence for optimizing postoperative rehabilitation strategies.

Methods

The study enrolled 49 patients followed up at 3 months postoperatively, 33 patients at 6 months, and 35 patients at 12 months. Twenty-nine healthy controls were recruited. A three-dimensional motion capture system was used to collect 6DOF knee kinematic data at 3, 6, and 12 months after surgery, including flexion-extension, internal-external rotation, adduction-abduction angles, and anterior-posterior, distal-proximal, medial-lateral translation data. Clinical function was assessed using the IKDC and KOOS scores. One Way ANOVA of one-dimensional statistical parametric mapping (SPM1D) was used to assess the changes in gait kinematics and differences compared to healthy controls.

Results

After ACLR, the IKDC and KOOS scores of patients significantly improved between 3 and 12 months postoperatively, showing good subjective functional recovery. Over the course of one year, the knee kinematic data of gait has gradually recovered. However, abnormalities in knee joint kinematics still exist. In the coronal plane, the adduction angle of the knee joint during motion is relatively large (p < 0.05); In the sagittal plane, the flexion angle increased during the standing phase (p < 0.05); In the transverse plane, the internal rotation angle of the knee joint increased compared to the controls (p < 0.05). The range of motion of flexion and rotational angles decreased compared to the controls (p < 0.05).

Discussion

The kinematic recovery of the knee joint in ACLR patients presents multidimensional characteristics and dynamic changes. The recovery rates and patterns differ significantly across dimensions, with some abnormalities not fully corrected within one-year post-urgery. These findings provide scientific evidence for individualized rehabilitation strategies, emphasizing the need for strengthening joint stability and range of motion recovery in the early postoperative phase (0-6 months) and focusing on correcting rotational and flexion-extension function during the later phase (6-12 months) to further improve knee function and prevent long-term adverse outcomes.

Reducing Walking Speed Decreases Surgical Knee Loading but Not Between-Limb Symmetry in Individuals With Anterior Cruciate Ligament Reconstruction

A higher risk of knee osteoarthritis (OA) has been identified in patients with slower walking speeds following anterior cruciate ligament reconstruction (ACLR). Given that altered loading of the surgical knee has been the most proposed mechanism for early knee OA post-ACLR, understanding how modulating walking speed may modify knee joint loading is essential for developing strategies to reduce the risk of knee OA in ACLR patients. The purpose of this study was to determine how modulation of walking speed affects knee joint loading during overground walking post-ACLR. Lower extremity kinematics and kinetics were recorded during overground walking at a self-selected, slower, and faster speed from 16 patients with unilateral ACLR. The results showed that ACLR patients demonstrated lesser peak knee flexion and adduction moments of the surgical knees when walking at slower speeds. However, modulating walking speed did not alter between-limb knee loading asymmetry. The ACLR limbs had lower peak knee flexion moments than the uninjured limbs across all 3 walking speeds. Although interventions that increase walking speed may deter the onset of knee OA by elevating the mechanical stimulation at the surgical knee, additional gait training strategies may be needed to restore the between-limb loading symmetry in ACLR patients.

Advancing Osteoarthritis Research: Insights from Rodent Models and Emerging Trends

Osteoarthritis (OA) is a degenerative joint disease that affects millions of individuals worldwide, causing pain, disability, and a significant burden on public health. Preclinical research using animal models is essential to our understanding of the underlying pathogenesis of OA and developing therapeutic strategies. Rodent models, in particular, have become indispensable in studying OA due to their ability to mimic various features of human disease. This review provides an overview of commonly used rodent models of OA, including surgical induction (e.g., destabilization of the medial meniscus and anterior cruciate ligament transection), chemical induction (e.g., monoiodoacetate-induced cartilage degeneration), and genetically modified models. Additionally, age-related OA models that naturally develop OA-like symptoms in aged rodents are also discussed. Despite their utility, rodent models face limitations in fully recapitulating the complexity of human OA. Emerging trends in OA research, including the use of 3D imaging for joint analysis, molecular profiling for deeper insights into disease mechanisms, and advancements in biomarkers for early detection and treatment, are highlighted. These innovations provide new opportunities to refine existing models and enhance the translation of findings to clinical therapies. This critical review provides comprehensive information for researchers working in OA and related fields, promoting a better understanding of the available rodent models and their applications in OA research.

Early Intervention With Boiogito to Suppress Knee Osteoarthritis Progression: An Experimental Approach Using a Medial Meniscus Instability Rat Model

Background Knee osteoarthritis (KOA) is a prevalent and chronic condition characterized by swelling, pain, and limited range of motion of the knee due to degenerative changes in joint structures, leading to impairment in performing daily activities. Although conservative treatments, such as exercise therapy and nonsteroidal anti-inflammatory drugs are employed, there are few effective therapeutic options for preventing disease progression. During early KOA, there is osteoclast proliferation in the subchondral bone, disruption in cartilage homeostasis, elevation of matrix metalloproteinase-13 (MMP-13) levels, and reduction in tissue inhibitors of matrix metalloproteinase-1 (TIMP-1) levels. Boiogito (BOT), which is a traditional Japanese medicinal formula, attenuates KOA progression, however, its effects when administered after KOA progression remain unclear. This study aimed to assess the therapeutic efficacy of BOT in preventing KOA progression in a rat model by focusing on its effects on motor function, subchondral bone turnover, and cartilage degradation in relation to the timing of administration. Methods A rat KOA model was created by destabilizing the medial meniscus (DMM). Rats were divided into Sham, DMM, DMM + BOT (0w, BOT administered immediately post-surgery), and DMM + BOT (3w, BOT administered 3 weeks post-surgery) groups. BOT was included in the diet at 1% (w/w). Motor function was evaluated biweekly by a treadmill running test, while structural changes in the knee were assessed by measuring the medial meniscus extrusion ratio (MMER) using computed tomography (CT). Histological and immunohistochemical analyses were conducted to evaluate joint degeneration via the Osteoarthritis Research Society International (OARSI) score, osteoclast numbers in subchondral bone through tartrate-resistant acid phosphatase (TRAP) staining, and MMP-13/TIMP-1 ratios in articular cartilage. Results Treadmill testing revealed that the DMM + BOT (0w) had significantly higher running speeds compared with the DMM and DMM + BOT (3w) groups. In all groups that underwent DMM surgery, the MMER was not significantly different. Histological assessments showed that the DMM + BOT (0w) group had lower OARSI scores and reduced osteoclast numbers in the subchondral bone compared with the DMM group. Immunohistochemical analysis showed a significant reduction in MMP-13 expression and MMP-13/TIMP-1 ratios in the DMM + BOT (0w) group, whereas the DMM + BOT (3w) group showed limited efficacy compared with the early intervention. Conclusion Early administration of BOT attenuates KOA progression by preserving motor function, reducing subchondral bone turnover, and mitigating cartilage degradation. These findings highlight the importance of early intervention with BOT to achieve optimal therapeutic outcomes in KOA.

Coordination of the Lower Limbs of Soccer Players after Anterior Cruciate Ligament Reconstruction with Allograft and Autograft during Landing

Objectives

Quantitative biomechanical tests, along with physical assessment, may be useful to understand kinematics associated with graft types in anterior cruciate ligament surgery, particularly in individuals aiming for a safe return to sport.

Methods

Sixty male soccer players in three groups participated in this study. Three equal groups of healthy, auto transplanted and allotransplanted participants, matched for age, gender, activity level and functional status, landed with one foot on a force plate. Their kinematic information was recorded by the motion analyzer and used to describe coordination the variability by measuring coupling angles using vector coding.

Results

The coordination variability of the allograft group in the surgical limb was significantly greater than that of the healthy group at least 9 months after the reconstructive surgery of the ACL and at the stage of return to sports, (F (6, 35) = 2.79, p = 0.025; Wilk's Λ = 0.676, partial η2 = 0.32). The coordination pattern in the surgical and healthy limbs of the surgical groups also differed from that of the healthy people, which was more pronounced in the allograft group, (F (6, 35) = 2.61, p = 0.034; Wilk's Λ = 0.690, partial η2 = 0.31).

Conclusion

These results show that the allograft group has a different coordination variability at return to sport than the healthy group, so they may need more time for excessive training and competition.