With the increasing advocacy for maintaining a healthy lifestyle in regards to exercise and the average age of the population in the U.S. growing older, there has been an increased incidence of arthritic knee damage as a result of osteoarthritis. Once non-procedural methods of treatment have been exhausted, such as NSAIDs and physical therapy, the most effective therapy to regain previous range of motion and quality of life is total knee arthroplasty (TKA). Additionally, TKA is useful to treat patients with rheumatoid disease once their knees have reached end-stage cartilage damage, although it does not restore function as well in these patients as it does in patients with osteoarthritis. Current technological developments have produced prostheses that mimic physiological movement and allow attachment of components positioned similarly to ligaments in the human knee, providing better longevity and functional recovery from the damaged state. The TKA procedure has become fast-tracked to limit the length of stay for patients and the cost to both the individual and the hospital. Though this change to fast-track procedures has helped limit post-operative complications, such as venous thromboembolism, multiple comorbidities and componentry failure continue to increase the risk of failure or revision of the procedure. With the projected increase in the need for TKAs in the future, it is important to review factors that may influence access and success of this procedure, for example, the effect socioeconomic status has on the ability of different patients to receive quality replacements and experience sustained quality of life. Multiple studies have shown that utilization of TKA differs between low income and high income populations, with racial minority populations undergoing the procedure less often as they represent a greater percentage of low income populations. Interestingly, low income patients report greater improvement in function when compared to high income patients, most likely due to low income patients being admitted with more severe knee damage when compared to the other population. Their satisfaction, along with financial constraints and insurance, are factors that lower the rate of revision for low income populations even though their measured range of motion post-operatively is not as good as that in high income populations on average. Social support has been determined to be a significant factor in determining whether patients will undergo TKA and follow the rehabilitation prescribed to them appropriately. Studies have shown less social support reported from minority groups, but not low income cohorts specifically. Using the current knowledge of the impact these differences in socioeconomic status can have on the outcomes of TKA, can help create healthcare environments which will optimize the success rate of TKA for all patients, regardless of socioeconomic status, and prevent unnecessary strain on the healthcare system due to avoidable post-operative issues. Future studies should determine what policies and procedures can be implemented to help aid patients, such as greater social support, and to support hospitals with limited resources in an effort to improve surgical outcomes.

BACKGROUND: Up to 37% of people with knee osteoarthritis (OA) present with varus thrust, an abrupt and dynamic worsening of varus alignment during the load-bearing stages of gait. Varus thrust is associated with up to 4-fold increased odds of medial knee OA progression as well as worsening clinical outcomes. While the implications of varus thrust have been well studied, the neuromuscular factors related to varus thrust are still not well understood and many studies report contradictory findings. Additionally, many potential factors remain unstudied. This warrants further efforts to determine associations between neuromuscular factors and varus thrust. The purpose of this study is to investigate knee muscle strength and muscle activation during walking in relation to biomechanical measures of varus thrust. METHODS: Analyses of existing data from participants with and without knee OA recruited at three institutions were used for this study. All participants underwent gait analyses at their self-selected pace while kinematics, kinetics, and surface EMG data were collected. Quadriceps and hamstrings strength was measured using isokinetic dynamometry. Gait data were used to calculate adduction excursion and peak knee adduction velocity as measures of varus thrust. A custom MATLAB code was used to calculate the rate of force development of the quadriceps, and a muscular co-contraction equation was used to calculate co-contraction values for four antagonist muscle pairs (VL-LH, VM-MH, VL-LG, and VM-MG) from surface EMG data during walking. Correlational analyses were performed to assess associations of strength, rate of force development, and muscle co-contraction variables with measures of varus thrust. RESULTS: A total of 183 participants were enrolled, however, a varying number of participants were used for different analyses based on available data. Peak isokinetic quadriceps strength at 60 degrees/second and peak hamstrings strength at both 60 and 120 degrees/second were negatively correlated with knee adduction velocity in people with knee OA. This association was not observed for people without knee OA. VLLH and VMMH co-contraction indices during preactivation were positively correlated with knee adduction excursion. VLLG co-contraction during midstance was positively correlated with peak knee adduction velocity. Association between rate of force development and varus thrust variables was not significant. CONCLUSIONS: Lower isokinetic thigh muscle strength and greater preactivation during walking are related to greater magnitude of varus thrust measured using motion capture. These results advance our understanding of neuromuscular factors related to varus thrust and could inform future interventions to reduce thrust and prevent further progression of OA. / 2020-06-14T00:00:00Z

A dissertation submitted to the Faculty of Health Sciences, University of the Witwatersrand, in fulfilment of the requirements for the degree of Master of Science in Medicine, Johannesburg, 2017 / Objective: Physical activity (PA) is recommended in the management of osteoarthritis (OA) to reduce pain and improve function. Total volumes of PA and sedentary behaviour (SB) have been described in people with knee OA, but detailed information about the patterns of accumulation of PA and SB in knee OA populations is lacking. The purpose of this study was to objectively assess the patterns of accumulation of PA and SB and to explore associations with subjectively measured functional outcomes and quality of life in patients with knee OA. Methods: End-stage knee OA patients (n = 87, 65 ± 8.8 (mean ± SD) years, body mass index 34.4 ± 7.8 kg/m2) with Kellgren-Lawrence-defined grade 3-4 radiographic OA, wore an Actigraph and an activPAL accelerometer for 24 hours a day for 7 consecutive days. Total volumes of SB, light physical activity (LPA), moderate to vigorous physical activity (MVPA), and different bouts of SB, LPA, and MVPA were assessed. Self-report questionnaires were used to assess patient-experienced pain, function, quality of life and activities of daily living were the Western Ontario and McMaster Universities (WOMAC) osteoarthritis index and the Knee Injury Osteoarthritis Outcome Score (KOOS). Results: Of the 87 knee OA patients only 76 and 65 had complete Actigraph and activPAL data respectively. The participants had a mean (SD) age of 65.0 (8.8) years, were mostly women and most were classified as being obese with an average BMI of 34.4 (7.8) kg/m2. The Actigraph mean (95% CI) of awake wear time was 15.6 (15.1-16) hours/day, SB 10.9 (10.5-11.4) hours/day, LPA 4.5 (4.1-5) hours/day and MVPA 8.2 (3.3-13) min/day. Approximately 7% of patients met the current recommended PA guidelines. The activPAL mean (95% CI) of sitting time, standing time, stepping time and number of steps were 9.3 (8.5 – 10.1) hours per day, 5.0 (4.4 – 5.6) hour per day, 76.5 (66.6 – 86.3) minutes per day and 2489 (2130 – 2848) minutes per day respectively. There were variations in the hourly patterns of movement behaviours. Participants were significantly less sedentary between 6 am and 9 am compared to the grand mean of sedentary time per hour over the day (p<0.01) and were significantly more sedentary per hour from 3 pm to 7 pm (p<0.05). Significant correlations were found between WOMAC pain scores and Actigraph measured SB (r=0.277, p=0.031), LPA (r=-0.240, p=0.043), MVPA (r=-0.242. p=0.042), number of steps (r=-0.282, p=0.020), number of breaks in bouts of SB greater than 20 minutes (r=-0.292, x p=0.016), average duration of breaks in SB (r=-0.277, p=0.024), average duration of MVPA bouts (r=-0.326, p=0.012). Significant correlations were also found between WOMAC activity of daily living scores and Actigraph measured LPA (r=-0.206, p=0.048), MVPA (r=-0.246, p=0.029), number of steps (r=-0.286, p=0.010) and average duration of MVPA bouts (r=-0.383, p=0.002). Significant correlations were found between WOMAC pain scores and activPAL sitting time (r=0.029, p=0.02), and stepping time (r=-0.029, p=0.01), between self-reported WOMAC activity of daily living score and stepping time (r=-0.309, p=0.02), between KOOS activity of daily living score and stepping time (r=-0.276, p=0.004), and between KOOS quality of life score and stepping time (r=-0.263, p=0.008). Conclusion: This study describes novel detail of the patterns of activity and sedentary behaviour in patients with knee OA. The use of two accelerometers gives a detailed account of daily activity and the variation throughout the day, highlighting when interventions to improve activity might be most effective. Therefore, interventions should target the long bouts of inactivity in this population. Since even healthy populations of older adults struggle to meet current recommended PA guidelines, it may be important to shift attention from meeting recommendations of MVPA to creating feasible suggestions of doing more light activity and breaking more sedentary time in knee OA patients. / XL2018

Note:

Total knee arthroscopy is one of the most performed and most successful orthopedic surgeries, with nearly a million procedures performed in 2020 in the United States alone. Due to changing patient demographics, the use of cementless fixation for implant stability is becoming more prevalent amongst recipients. Cementless implants rely on the surface morphology of a porous coating to bond implant to bone; the quality of this bond is dependent on an interference fit and the roughness, or coefficient of friction, between implant and bone. Stress shielding is a comparison of the properties in implanted bone to natural bone; it is a commonly used measurable when using a finite element model to optimize implant design. The purpose of this study is to investigate how different coating types (coefficients of friction) and the location of their application affect the stress shielding response in the tibia. A finite element model was constructed to investigate the impact of these variables. The results concluded that the stress distribution in an implanted tibia is dependent on the coefficient of friction applied at the tip of the stem. Lower friction coefficients applied to the stem tip resulted in higher compressive stresses, and higher friction coefficients resulted in lower compressive stresses. Thus, lower friction coefficients provided more favorable stress shielding responses, however, at the expense of stress concentrations of greater magnitude.

The knee is the most common site of osteoarthritis (OA) and is one of the leading causes of disability in older adults affecting over 53 million people in the United States and more than 302 million people worldwide. These numbers are only expected to grow because of the rise of diseases such as obesity, demographic shifts to an older population, and a more sedentary lifestyle. The rise of obesity and a more sedentary lifestyle comes with increases in joint loading which along with the aging population creates worse outcomes in proprioception. All of which can contribute to worsening OA. Despite the great costs to quality of life and society, there is no cure for OA. Only treatments exist to treat the symptoms of OA; and since knee pain is one of the most common symptoms of OA, it is a powerful driver for treatment because of the disruptive nature it can have on quality of life. Therefore, many treatments focus on pain relief and exercise to reduce the pain and worsening of OA. Radio frequency nerve ablation (RFA) is a procedure that is increasingly being performed for those who want an alternative before resorting to or are not a good match for total knee arthroplasty (TKA). Because RFA is minimally invasive, it can be performed on an outpatient basis and has been shown to be effective in reducing pain for at least 24 months for most patients. Despite the benefits in pain reduction, little is known about the biomechanical effects of RFA and its consequences on proprioception. However, based on prior studies into the pain relieving effects of interventions such as celecoxib or HA injections, we can hypothesize that with a decrease in pain, knee loading increases. Therefore, the pain relieving effects of RFA may increase the incidence of OA. Furthermore, because the RFA procedure involves ablating nerves that carry sensory information, changes to proprioception are expected. However, currently there is no information regarding its effect on proprioception. Again, using prior research that studies the consequences of reduced proprioception on those with OA, we can hypothesize that with RFA, proprioception would be further reduced compared to the reductions experienced by people with OA already, and it may also lead to worsening OA outcomes. Despite the possible issue of worsening OA outcomes with RFA, the pain relieving effects cannot be discounted as it is one of the most disruptive symptoms of OA. Therefore, effects of RFA on knee biomechanics and proprioception should be studied to understand the long-term impacts of this procedure.

A randomized, controlled, clinical trial of a yoga-based exercise intervention for knee osteoarthritis / Background: Knee osteoarthritis is a chronic disease involving the breakdown of joint tissues resulting in pain and disability. Exercise provides equivalent pain relief to medication, improves physical functioning, and ameliorates co-morbidities. However, certain forms of exercise can potentially overload the joint and exacerbate symptoms; the optimal type is unknown. We developed a yoga-based exercise intervention designed for knee osteoarthritis by incorporating postures that minimize a mechanical loading variable implicated in disease progression. Purpose: The objective was to compare the efficacy of this biomechanically-tailored yoga program as treatment for knee osteoarthritis with the current “gold standard” of physical therapy, and a no-exercise attention control group. Methods: A single-blinded, 12-week, 3-arm, parallel randomized control trial was conducted. Participants (women 50 years or over, with clinical knee osteoarthritis; n=31) were stratified by disease severity and randomized to receive biomechanical yoga exercise (YE; n=10), traditional exercise (TE; n=11), or no-exercise (NE; n=10). The primary outcome measure was pain; secondary outcomes included patient-reported physical function and mobility performance; and tertiary outcomes included muscular strength, quality-of-life, and symptoms of depression. Results: The YE and TE groups demonstrated statistically and clinically significant within-group improvements in pain, physical function, and mobility performance (p<0.017), while the NE group did not. The YE group reported greater improvements in pain compared to the NE group (p=0.003). The YE group also demonstrated greater improvements in physical function compared to NE (p=0.010). There were no significant between-group differences in mobility performance, strength, quality-of-life, or depression (p>0.05). Conclusion: Yoga appears as an efficacious and well-tolerated conservative treatment option for women with knee osteoarthritis. The yoga intervention yielded comparable, and in some cases possibly greater improvements in the major burdening symptoms of the disease compared to traditional physical therapy. Future investigations with larger samples are warranted to establish effectiveness and possibly superiority to traditional exercise. / Thesis / Master of Science (MSc) / Osteoarthritis of the knee is a debilitating joint disease and a leading cause of disability. Treatment often involves medication to control pain and surgery when drugs fail. Exercise is a conservative approach to improve symptoms and quality of life. Some forms of exercise however can overload the knee and possibly worsen the disease. We have developed a yoga-inspired exercise regimen specifically for knee osteoarthritis that minimizes damaging mechanical loads. To test this program, women with knee osteoarthritis were randomly assigned to receive either 12 weeks of yoga, traditional physical therapy, or no-exercise. Before and after the intervention, pain, physical function, and mobility were measured. The yoga and traditional exercise groups demonstrated improvements in pain, physical function, and mobility; while the no-exercise group did not. In some aspects, yoga even outperformed traditional exercise. These findings suggest yoga is as effective as traditional exercise, and potentially more so, in treating knee osteoarthritis.

This is Part A. / Abstract Not Provided. / Thesis / Master of Engineering (MEngr)

Anterior cruciate ligament (ACL) injuries are common orthopaedic injuries among athletes who participate in sports that involve cutting and changing directions. Many of these adolescent athletes intend to return to sports (RTS), and therefore undergo ACL reconstruction (ACLR). These athletes exhibit unfavorable landing biomechanics from muscle atrophy and asymmetrical neuromuscular control post-ACLR, putting them at a higher risk of re-injury. Thus, rehabilitation following ACLR is important to improve kinetic and kinematic outcomes and reduce re-injury risk. Biofeedback during rehabilitation is thought to be one way to potentially restore neuromuscular control deficits of athletes recovering from ACLR. Therefore, understanding the effectiveness of a biofeedback intervention on factors associated with re-injury among post-ACLR patients is essential in successful RTS. The purpose of this study is to analyze the effect of a 6-week biofeedback intervention on eccentric knee joint power (ECCKP), limb stiffness, and limb stiffness symmetry (using normalized symmetry index, NSI), in addition to secondary lower extremity outcomes that are associated with these metrics, during landing among patients following ACLR. This study used data collected from an ACL-Biofeedback Trial (ClinicalTrials.gov: AR069865) where participants were randomized into a biofeedback (BF) or control group (C). The BF group received visual and tactile feedback during a series of controlled squats while the C group participated in several online and in-person educational sessions. Participants completed 10 stop-jump tasks before (pre), after (post), and 6 weeks after (ret) the intervention. Kinetic, kinematic, and ground reaction forces (GRF) were collected from embedded force plates and 3D motion capture. Partaking in a biofeedback intervention did not improve ECCKP, limb stiffness, or limb stiffness NSI compared to controls. A group-by-time interaction was found for hip excursion (p=0.035), and a main effect of time was found for ECCKP, with this variable increasing by 18.5% from pre to ret (p=0.001). In addition, when considering surgical versus non-surgical limbs, this cohort exhibited interlimb asymmetries in stiffness, peak resultant GRF (rGRF), and time to reach peak rGRF (p<0.009). Further, a group-by-limb interaction (p=0.005) and a 7.1% reduction in peak rGRF were found from post to ret (p=0.02). Participants in this study also exhibited limb stiffness asymmetry greater than 10%, which supports existing literature that observed interlimb asymmetries in athletes following ACLR around the typical RTS time (9-12 months post-ACLR). The results from this analysis demonstrated that the current biofeedback intervention was inadequate in improving ECCKP, limb stiffness, and limb stiffness NSI, but additional biofeedback studies with larger sample sizes that investigate task dependencies are needed to better understand the effectiveness of biofeedback interventions. / Master of Science / Anterior cruciate ligament (ACL) injuries are common orthopaedic injuries among athletes who participate in sports that involve cutting and changing directions. Many of these adolescent athletes intend to return to their pre-injury level, therefore undergo a surgical procedure called ACL reconstruction (ACLR). However, following this procedure, athletes display unsafe and stiff landing patterns due to muscle weakness and asymmetrical neuromuscular, or mind-body, control post-ACLR, which increases their risk of re-injury once they return to sport (RTS) following recovery. Rehabilitation for patients following ACLR is of the utmost importance in improving unsafe movement patterns to reduce the risk of re-injury. Biofeedback training refers to receiving external signals that can be processed and transferred to the muscles in the body. This technique aims to restore the neuromuscular deficits of athletes following ACLR and could potentially be helpful during ACLR rehabilitation. Therefore, understanding the effectiveness of a biofeedback intervention on outcomes associated with an increased risk of re-injury in patients following ACLR is important to safely RTS. The purpose of this study is to determine the effect of a 6-week biofeedback intervention on the ability of the knee to absorb impact forces (quantified as eccentric knee joint power, ECCKP), limb stiffness, and limb stiffness symmetry (measured with normalized symmetry index, NSI), along with secondary outcomes related to these variables, among patients following ACLR. This study used data collected from an ACL-Biofeedback Trial (ClinicalTrials.gov: AR069865) where participants were randomized into a biofeedback (BF) or control group (C). The BF group received visual and resisted feedback during a series of controlled squats while the C group participated in several online and in-person educational sessions. Participants completed 10 stop-jump tasks before and after the intervention, and biomechanical data was obtained. The biofeedback intervention did not result in an improved ability for the knee to absorb impact from landing, and it was not able to decrease limb stiffness or limb stiffness asymmetry. It was able to improve hip excursion, which allows for a favorable, less upright posture when landing. ECCKP improved for both groups, indicating that the biofeedback did not add extra benefit to the participant's rehabilitation outside of the study. Asymmetries were observed between the surgical and non-surgical limbs in limb stiffness, peak GRF, and the time it takes to reach this peak GRF. This sample exhibited limb stiffness asymmetry greater than the recommended 10% threshold, raising concern for when these athletes RTS. The results from this analysis demonstrated that the current biofeedback intervention was inadequate in improving ECCKP, limb stiffness, and limb stiffness NSI, but biofeedback in ACLR rehabilitation can still be efficacious in improving hip biomechanics and overall neuromuscular control but may be task-dependent and call for a larger sample size.

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