Knee biomechanics and contralateral knee osteoarthritis progression after total knee arthroplasty

Staged Bilateral Total Knee Arthroplasty: Differing Results Comparing the First and Second Knees

BACKGROUND

Patients often prefer one knee over the other following staged bilateral total knee arthroplasty (BTKA). Our study compared patient-reported outcomes scores of each knee following BTKA and identified factors that may contribute to the identified discrepancies.

METHODS

All patients who underwent staged BTKA between July 2014 and August 2022 were identified. The patient-reported outcomes were collected preoperatively and at 2 weeks, 6 weeks, 1 year, and 2 years postoperatively. Each knee's results were compared using paired t-tests and McNemar tests. Preoperative Kellgren-Lawrence Grade (KLG), postoperative range of motion (ROM), reoperation rates, and manipulations under anesthesia (MUAs) were collected. Results were stratified based on time between TKAs (< 3 months, 3 to 12 months, 1 to 2 years, and > 2 years).

RESULTS

There were 911 patients who underwent staged BTKA, with a mean 4.1-year follow-up. The ROM, patient satisfaction, MUAs, and reoperations were not significantly different between knees. Comparing the KLG of the first and second knees, 71% had the same KLG for both knees, 21% had a lower KLG, and 7% of the second knees had a higher KLG. The first knee had greater pain reduction (-10.6 at 2 weeks, -27.4 at 6 weeks) compared to the second (9.3 at 2 weeks, -8.1 at 6 weeks) (P < .0001) and better improvement in Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS JR) score (8.5 at 2 weeks, 16.9 at 6 weeks) compared to the second (-5.8 at 2 weeks, 5.0 at 6 weeks) (P < .0001). The 1-year outcomes between first and second knees, or recovery curves, were not different when stratifying by time between TKAs.

CONCLUSIONS

The second knee in a staged BTKA has less delta improvement in KOOS JR and pain scores at early follow-up, likely due to higher starting KOOS JR and Patient-Reported Outcomes Measurement Information System scores, despite similar final patient satisfaction and clinical outcome measures. Lower KLG in the second total knee arthroplasty (TKA) may contribute to these findings. An MUA after the first TKA is highly predictive of an MUA after the second TKA.

Lower extremity muscle patterns and frontal plane biomechanics are altered in the contralateral knee of adults with osteoarthritis compared to asymptomatic adults

PURPOSE

To compare knee joint muscle activity during gait between the contralateral limb of individuals with knee osteoarthritis (OA) and an asymptomatic older adult group. A secondary objective was to compare frontal and sagittal plane moment and sagittal plane motion features between groups.

SCOPE

84 individuals with moderate knee OA (61 ± 6 years, 43 % female, BMI 29.2 ± 5.7 kg/m2), and 45 asymptomatic older adults (61 ± 7 years, 49 % female, BMI 25.0 ± 3.4 kg/m2) participated. Participants walked at a self-selected pace on a dual belt treadmill. Surface electromyograms of the quadriceps, hamstrings, and gastrocnemius, segment motions and ground reaction forces were recorded. Principal component analyses identified amplitude and temporal electromyogram features. Sagittal plane motion and net external sagittal and frontal plane moments were calculated. Analysis of Variance models using Bonferroni corrections determined between and within group differences in these gait features.

CONCLUSIONS

The contralateral knee showed prolonged lateral hamstring activation and altered temporal features of the gastrocnemius and greater knee adduction moments compared to asymptomatic adults. Group, muscle, or interaction effects were not found for the quadriceps. These findings highlight the importance of exploring the implications of contralateral knee function of individuals with moderate knee OA, particularly considering the altered antagonist muscle activations, and heightened frontal plane moments.

Morphology and transverse alignment of the patella have no effect on knee gait characteristics in healthy Chinese adults over the age of 40 years

Background: The influence of patella morphology and horizontal alignment on knee joint kinematics and kinetics remains uncertain. This study aimed to assess patella morphology and transverse alignment in relation to knee kinetics and kinematics in individuals without knee conditions. A secondary objective was to investigate the impact of femur and tibia alignment and shape on knee gait within this population. Patients and methods: We conducted a prospective collection of data, including full-leg anteroposterior and skyline X-ray views and three-dimensional gait data, from a cohort comprising 54 healthy individuals aged 40 years and older. Our study involved correlation and logistic regression analyses to examine the influence of patella, femur, and tibia morphology and alignment on knee gait. Results: The patellar tilt angle or the patella index did not show any significant relationships with different aspects of gait in the knee joint, such as velocity, angle, or moment (p > 0.05, respectively). Using multivariate logistic regression analysis, we found that the tibiofemoral angle and the Q angle both had a significant effect on the adduction angle (OR = 1.330, 95%CI 1.033-1.711, p = 0.027; OR = 0.475, 95%CI 0.285-0.792, p = 0.04; respectively). The primary variable influencing the knee adduction moment was the tibiofemoral angle (OR = 1.526, 95% CI 1.125-2.069, p = 0.007). Conclusion: In healthy Chinese individuals aged over 40, patella morphology and transverse alignment do not impact knee gait. However, the femoral-tibial angle has a big impact on the knee adduction moment.

Finding the Goldilocks Zone of Mechanical Loading: A Comprehensive Review of Mechanical Loading in the Prevention and Treatment of Knee Osteoarthritis

In this review, we discuss the interaction of mechanical factors influencing knee osteoarthritis (KOA) and post-traumatic osteoarthritis (PTOA) pathogenesis. Emphasizing the importance of mechanotransduction within inflammatory responses, we discuss its capacity for being utilized and harnessed within the context of prevention and rehabilitation of osteoarthritis (OA). Additionally, we introduce a discussion on the Goldilocks zone, which describes the necessity of maintaining a balance of adequate, but not excessive mechanical loading to maintain proper knee joint health. Expanding beyond these, we synthesize findings from current literature that explore the biomechanical loading of various rehabilitation exercises, in hopes of aiding future recommendations for physicians managing KOA and PTOA and athletic training staff strategically planning athlete loads to mitigate the risk of joint injury. The integration of these concepts provides a multifactorial analysis of the contributing factors of KOA and PTOA, in order to spur further research and illuminate the potential of utilizing the body's own physiological responses to mechanical stimuli in the management of OA.

The Immediate Effect of Backward Walking on External Knee Adduction Moment in Healthy Individuals

Backward walking (BW) has been recommended as a rehabilitation intervention to prevent, manage, or improve diseases. However, previous studies showed that BW significantly increased the first vertical ground reaction force (GRF) during gait, which might lead to higher loading at the knee. Published reports have not examined the effects of BW on medial compartment knee loading. The objective of this study was to investigate the effects of BW on external knee adduction moment (EKAM). Twenty-seven healthy adults participated in the present study. A sixteen-camera three-dimensional VICON gait analysis system, with two force platforms, was used to collect the EKAM, KAAI, and other biomechanical data during BW and forward walking (FW). The first ( $P<0.001$ ) and second ( $P<0.001$ ) EKAM peaks and KAAI ( $P=0.02$ ) were significantly decreased during BW when compared with FW. The BW significantly decreased the lever arm length at the first EKAM peak ( $P=0.02$ ) when compared with FW. In conclusion, BW was found to be a useful strategy for reducing the medial compartment knee loading even though the first peak ground reaction force was significantly increased.