Vertical ground reaction force 2 years after anterior cruciate ligament reconstruction predicts 10-year patient-reported outcomes

Osteoarthritis year in review 2024: Biomechanics

OBJECTIVE

We aimed to systematically review and summarize the literature of the past year on osteoarthritis (OA) and biomechanics, to highlight gaps and challenges, and to present some promising approaches and developments.

METHODS

A systematic literature search was conducted using Pubmed and the Web of Science Core Collection. We included original articles and systematic reviews on OA and biomechanics in human subjects published between April 2023 and April 2024.

RESULTS

Of the 155 studies that met the inclusion criteria, 9 were systematic reviews and 146 were original (mostly cross-sectional) studies that included a total of 6488 patients and 1921 controls with a mean age of 57.5 and 44.7 years, respectively. Promising advances have been made in medical imaging of affected soft tissue structures, the relationship between soft tissue properties and biomechanical changes in OA, new technologies to facilitate easier assessment of ambulatory biomechanics, and personalized physics-based models that also include complex chemical and mechanobiological mechanisms, all of which are relevant to gaining mechanistic insights into the pathophysiology of OA.

CONCLUSIONS

There is still an unmet need for larger longitudinal data sets that combine clinical, radiological, and biomechanical outcomes to characterize the biomechanical fingerprint that underlies the trajectory of functional decline and biomechanical phenotypes of OA. In addition, criteria and guidelines for control groups, as well as methods and standards for model verification allowing for comparisons between studies are needed.

Long-Term Outcomes of Anterior Cruciate Ligament Reconstruction Based on Gait Analysis

BACKGROUND

Currently available studies on the long-term functional outcomes of anterior cruciate ligament (ACL) reconstruction have yielded conflicting results. The purpose of this study was to evaluate the biomechanical characteristics of walking in the long term after ACL reconstruction.

METHODS

The study included a test group of 18 patients (3.4 years from the date of ACL reconstruction on average) and a control group of 20 healthy subjects. Their gaits were assessed using functional tests at voluntary walking and fast-walking speeds. The biomechanical assessments utilized included spatiotemporal and kinematic parameters of walking, as well as surface electromyography (EMG) amplitudes of the main flexor-extensor muscles of the lower extremities.

RESULTS

Fast-walking speeds and the clearances of the operated-upon limbs in the patient group exceeded those in the control group. The gait cycle in the patient group was significantly longer when walking at a voluntary speed compared to the control group. In the patient group, most of the movements were symmetrical at both speeds, and the parameters did not differ from the control group. The only exception was the hip joint amplitude and the main amplitude of the knee joint flexion, which significantly and simultaneously increased when walking at a fast speed.

CONCLUSIONS

In the postoperative period, at voluntary speeds, the patient group was characterized by increased amplitudes in the hip and knee joints and higher EMG amplitudes, which almost disappeared at higher speeds.

Qualitative and Quantitative Measures in the Infrapatellar Fat Pad in Older Adults: Associations with Knee Pain, Radiographic Osteoarthritis, Kinematics, and Kinetics of the Knee

RATIONALE AND OBJECTIVES

The purpose of this study is to delineate cross-sectional associations between qualitative and quantitative measures of the infrapatellar fat pad (IPFP) and knee symptoms, structure, kinematics, and kinetics in older adults.

METHODS

Ninety eligible subjects (90 knees, mean age 54.0 years, 68.9% female) were examined at our center. We used T2-weighted fat-suppressed magnetic resonance imaging (MRI) to evaluate signal intensity alteration, maximum sagittal area, and depth of the IPFP. Symptomatic osteoarthritis (SOA) was a pain subscale score greater than 0 on the Western Ontario McMaster Osteoarthritis Index. A Kellgren-Lawrence grade ≥ 2 identified incident radiographic osteoarthritis (iROA). Three-dimensional gait data were employed to analyze knee joint kinematics and kinetics. Correlation and regression analyzes assessed associations between IPFP measurements and SOA, iROA, kinematics, and kinetics.

RESULTS

There were strong and positive associations between IPFP signal intensity alteration and both SOA and iROA in multivariable regression analyzes [OR (95% CI): 2.849 (1.440 to 5.636), 2.356 (1.236 to 4.492), respectively]. Conversely, a significant negative correlation was observed between IPFP maximum area and flexion angle [B (95%CI): - 1.557 (-2.549 to -0.564)]. Moreover, adjusting for covariates did not reveal any significant correlation between IPFP parameters and other indicators (P > 0.05, respectively).

CONCLUSION

IPFP signal intensity alteration and area were associated with knee clinical symptoms, structural abnormalities, and flexion angle in adults over 40, respectively. These findings suggest that IPFP may be a crucial imaging biomarker in early and middle knee osteoarthritis.

Sex differences in dynamic joint stiffness during walking in older adults

BACKGROUND

Knee osteoarthritis (OA) often occurs in older women. Walking assistance such as knee brace is used to reduce mechanical stress on the knee, preventing OA onset. Dynamic joint stiffness (DJS) quantifies the resistance of an assistive device, providing a foundation for an objective bending stiffness prescription model. DJS may show sex differences among older adults.

RESEARCH QUESTION

This study aimed to investigate sex differences in lower limb DJS in the sagittal plane during walking in older adults.

METHODS

A total of 132 healthy older adults, aged 65 years or older (71 men and 61 women), were extracted from a public dataset. DJS of the hip, knee, and ankle joints in the sagittal plane was determined during the power absorption phase of the stance. DJS, joint angular excursion, and Δ joint moment were compared between older men and women using the Mann-Whitney U test. In addition, the r-value was calculated to represent the effect size of the differences in amplitude.

RESULTS

Ankle DJS in older women was significantly lower with a reduced Δ ankle plantar flexion moment compared with that into men (p < 0.001 and p = 0.001; r = 0.35 and 0.42, respectively). Additionally, knee DJS was lower in older women (p = 0.007). However, since the joint angular excursion and ΔMoment showed no differences (p = 0.624 and 0.222, respectively), the effect size was small (r = 0.24). Hip DJS showed no significant sex differences (p = 0.703).

SIGNIFICANCE

These results suggest that the decrease in ankle DJS in older women was caused by the reduced ankle plantarflexion moment. Thus, support for ankle DJS is necessary for healthy older women. Nonetheless, knee DJS does not elucidate the cause of knee OA in the older women.

Osteoarthritis year in review 2021: mechanics

Osteoarthritis (OA) has a complex, heterogeneous and only partly understood etiology. There is a definite role of joint cartilage pathomechanics in originating and progressing of the disease. Although it is still not identified precisely enough to design or select targeted treatments, the progress of this year's research demonstrates that this goal became much closer. On multiple scales - tissue, joint and whole body - an increasing number of studies were done, with impressive results. (1) Technology based instrument innovations, especially when combined with machine learning models, have broadened the applicability of biomechanics. (2) Combinations with imaging make biomechanics much more precise & personalized. (3) The combination of Musculoskeletal & Finite Element Models yield valid personalized cartilage loads. (4) Mechanical outcomes are becoming increasingly meaningful to inform and evaluate treatments, including predictive power from biomechanical models. Since most recent advancements in the field of biomechanics in OA are at the level of a proof op principle, future research should not only continue on this successful path of innovation, but also aim to develop clinical workflows that would facilitate including precision biomechanics in large scale studies. Eventually this will yield clinical tools for decision making and a rationale for new therapies in OA.