OBJECTIVE: To investigate the effect of a 12-week exercise-based physical therapy on movement-evoked pain (MEP) in knee osteoarthritis (OA) and assess the relations between baseline psychological factors and treatment responses based on MEP. BACKGROUND: Pain during movement (i.e., MEP) is one of the most common complaints amongst people with knee OA, which induces greater functional challenges during daily activities. Although the worsening of pain during exercise appears to hinder activity-based treatment adherence, the assessments of MEP tend to be overlooked in the pain management in knee OA. METHODS: The data analyzed in this study was from the parent study, Wearable Sensors in Knee Osteoarthritis (WESENS-OA) study, a longitudinal, single-arm clinical trial of a 12-week exercise intervention in people with symptomatic knee OA. In the WESENS-OA (n = 60), participants self-reported pain intensity during the nominated activity as well as psychological symptoms (Center for Epidemiologic Studies Depression Scale), cognitive pattern (Pain Catastrophizing Scale), and central sensitization (Central Sensitization Inventory). Pain intensity during functional tasks and strength testing were collected during the laboratory visits. Three characteristics of MEP outcomes were assessed: (1) pain during the nominated activity, (2) functional MEP, and (3) exercise MEP. The participants reported the pain intensity during the nominated activity that is most troublesome due to their knee pain weekly using the 11-point numerical rating scale (NRS, range: 0-10). Pain intensity during or immediately after functional tasks (i.e., 6-minute walking, chair stand, climbing the staircase, range: 0-10) and strength testing (i.e., maximal voluntary isometric contractions of knee extensors and flexors, isokinetic knee flexion-extension at 60°/s and 120°/s each, range: 0-10) were evaluated to measure functional MEP or exercise MEP, respectively. MEP index score (i.e., maximum pain corrected for baseline pain) was reported as the outcome. Mixed model repeated measures (MMRM) analysis was utilized to evaluate the effect of an exercise intervention on the change in movement-evoked pain from baseline to 12 weeks, and least square means with the standard error were reported simultaneously. Each participant’s treatment response was determined by comparing the change in MEP from baseline to Week 12. A participant with a difference of ≥ 2 points in NRS for pain-nominated activity was classified as a responder, and for functional MEP and exercise MEP, treatment responder classification was done based on the hierarchical agglomerative clustering analysis. After dichotomizing participants, using binomial regression, the relative risk (RR) was reported to explore the predictive ability of CSI, CES-D, and PCS on treatment response based on MEP. RESULTS: For pain during nominated activity, the mean difference (MD) from baseline to Week 6 was -1.72 with 95% CI (-2.35 to -1.08; P <0.0001), and the difference at Week 12 was -2.41 with 95% CI (-2.92 to -1.89; P <0.0001). For functional MEP, MD with 95% CI at Week 6 was -0.34 (-0.52 to -0.16; P = 0.0003), and at Week 12 was -0.44 (-0.58 to -0.31; P<0.0001). Unlike the other MEP measures, for exercise MEP, MD was measured at one timepoint, at Week 12, which was -0.58 with 95% CI (-0.88 to -0.27; P = 0.003). Our secondary analysis did not provide evidence that baseline measures of CSI, CES-D, and PCS were associated with the treatment response based on the change in MEP measures after the exercise intervention. CONCLUSION: In conclusion, our study strongly supports the effect of exercise on reduction in three measures of MEP—pain during nominated activity, functional MEP, and exercise MEP. Our hypothesis to confirm the predictive ability of psychological factors on treatment response based on MEP was not reached, with insufficient evidence to substantiate such a notion. However, our findings hold strength to pioneer discovering the underlying mechanism of understudied MEP in knee OA. / 2026-02-28T00:00:00Z

“Excessive” and/or “delayed” subtalar joint (STJ) pronation has been linked to overuse injuries because of its influence on tibial internal rotation (TIR). The transfer of STJ pronation to TIR occurs via the talocrual joint, believed to have limited transverse plane motion. However, studies have shown the talocrural joint to have more transverse plane motion than once believed, therefore it is feasible that the STJ will only influence the motion of the tibia once this motion has been exhausted. Currently, studies evaluating this relationship have focused on peak joint angles and excursion without reference to the amount of motion available at the ankle joint complex (AJC). Therefore the purpose of these studies were to evaluate whether runners with anterior knee pain (AKP) utilize a greater percentage of their available eversion motion (eversion buffer), evaluate the effects of small eversion buffers on coordination, and evaluate the influence of orthotics on those with AKP and with the smallest eversion buffers. This study found healthy and injured runners, for the most part, presented with no significant differences in traditional pronation related variables. The one exception was peak pronation velocity, where injured runners demonstrated faster velocities. On the other hand injured runners had significantly smaller eversion buffers which lead them to change their coordinative pattern earlier during stance. This difference in pattern also caused the intra-individual coupling variability to peak earlier during stance. Orthotics successfully controlled the kinematics of the AJC and increased the eversion buffer of injured runners and in those displaying the smallest buffers. While orthotics successfully influenced the kinematics of the AJC, they did not influence those of the tibia and knee. These changes at the AJC did not have a strong impact on the coordinative patterns of the lower extremity, however demonstrated a trend toward being able to influence the intra-individual coupling variability. In summary, injured runners demonstrated smaller eversion buffers and changed their coordinative pattern earlier during stance. While orthotics successfully increased the eversion buffer, they did not strongly influence coordination variables. Future studies analyzing pronation related variables in injured populations should evaluate them relative to the available motion at the AJC.

<p> Osteoarthritis (OA) is the most common arthritis, and the second most common diagnosis leading to disability. While loss of joint function is disabling, patients report that the greatest disabler of OA is the pain. Unfortunately, OA pain remains an unmet medical need. Numerous mechanisms have been proposed for the pathogenesis of OA pain. However, none of these mechanisms has led to satisfactory evidence-based treatment for OA pain. There is a critical need to address the mechanisms for OA pain due to the aging demographics and the prevalence of OA in older adults. This thesis project was aimed to study neural mechanisms for OA pain. The general hypothesis was that the pain of OA arises as a result of phenotypic changes in primary sensory neurons, especially in larger diameter A-fiber neurons. In vivo intracellular recordings were used to determine changes in specific populations of DRG neuron in a surgical knee derangement model of OA in the rat. It was found that AB-fiber low threshold mechanoreceptors, particularly muscle spindle afferents underwent significant changes (including changes in action potential configurations and in responses to repetitive stimulation) one month following the model induction when histopathological changes of the knee joint and the nocifensive behaviors of the affected lower limb favor OA. Nociceptors, including C-, As- and AB-fiber neurons remained largely unchanged at one month OA. AB-fiber high threshold mechanoreceptors exhibited significant changes at two month OA, a later phase during the progression of OA. The data demonstrate that distinct populations of dorsal root ganglia neuron are altered during the progression of OA, which might be the neuronal basis for clinical presentations of sensory deficit in OA including pain and loss of proprioception. The data also suggest that the pain in OA might be a form of neuropathic pain. </p> / Thesis / Doctor of Philosophy (PhD)

Despite the well-researched impact of ACL injuries, both acutely and longitudinally, and even though adolescent females have the highest risk of sustaining an ACL injury, there is surprisingly very little biomechanical research conducted on adolescent populations after an ACL rupture has taken place. The increasing rates of ACL injuries and re-injury among adolescents demonstrates a need for improved rehabilitation and return-to-activity (RTA) guidelines that are age/maturity- and sex-appropriate. To accomplish this, the first step is to describe this population alongside a non-injured activity-, maturity- and sex-matched population. Therefore, the overall purpose of this Doctoral thesis was to provide evidence to support the creation of return-to-activity guidelines for adolescent patients with ACL injuries. The findings of this thesis, briefly outlined below, can directly contribute to improving clinical and rehabilitation management of ACL injuries among adolescent males and females. First, a systematic review was performed to synthesize sex differences in muscle activation patterns in movements associated with ACL injuries in both adult and adolescent populations. Ultimately, 30 articles were included in the review with a wide range of inconsistent findings. In brief, females demonstrated higher pre- and post-landing activation of the quadriceps and lower activation of the hamstrings in 15 of 27 studies. Females also had higher quadriceps-to-hamstring co-contraction ratios during pre- and post-landing phases compared to their male counterparts in 4 of 9 studies. What's more concerning was the identification of only five research articles that evaluated muscle activations in adolescent or younger cohorts, further emphasising the importance of addressing this gap in literature. The second article of this thesis explored metrics used to evaluate knee joint function that are often a part of rehabilitation guidelines, such as limb symmetry indices (LSI) during single limb hopping and strength tasks. To date, no evidence exists to support or refute the use of these measures in an adolescent population. Therefore, we sought to investigate LSIs and knee joint function among adolescent males and females with and without ACL-injuries during single-limb assessments. A total of 141 participants were recruited and evaluated during a series of maximum voluntary tasks; isometric knee extension and flexion, and single-limb hopping tasks (anterior-hops, lateral-hops, 6m timed-hops, cross-hops, and triple-hops). In brief, females and males with ACL injuries had lower performance metrics compared to their matched controls, however, the differences were not the same within each sex. Females displayed deficits in all tasks, whereas males with and without ACL injuries were only different in the anterior-hop, triple-hop, and knee extension tasks. The final two articles of this thesis are complimentary as they both explored knee stabilisation strategies during countermovement jumps (CMJs) and side-cutting tasks. However, Article 3 included only adolescent males and females without ACL injuries to identify the influence of sex and limb-dominance on knee stabilisation strategies, whereas Article 4 included the same uninjured cohorts but compared with matched groups of males and females with ACL injuries. In both studies, surface electromyography and full-body kinematics were captured during CMJs and side-cutting. Knee stabilisation strategies were evaluated using co-activation indices (CIs), full muscle waveforms, knee joint flexion stiffness (KJFS) and knee joint sagittal and frontal excursions (KJSE and KJFE, respectively). In Article 3, sex differences were observed in CIs, with females having higher medial CIs in the non-dominant limb in both CMJs and side-cuts, and higher total CIs in the non-dominant limb during side-cuts. Between-limb differences were present in both sexes. Females had higher total CI in their non-dominant limb in CMJs and higher frontal KJE in their non-dominant limb during the stance phase of side-cuts. Males had higher medial CIs in their dominant limb in CMJs and higher sagittal KJE in their non-dominant limb during the preparatory and landing phases of CMJs. No significant sex or limb differences were identified in individual muscle activations or KJFS. Based on these findings, males and females were treated statistically independent when evaluating the effect of ACL-injury in Article 4. Interestingly, when comparing groups, only one significant effect of injury was observed in knee stability metrics; males with ACL injuries had significantly higher vastus medialis activity during the preparatory phase of the CMJ compared to their uninjured counterparts. There were no other significant differences in either task. Despite the importance of ACL injury prevention in adolescents, the evidence on sex difference in muscle activation patterns in this population is still scarce. The results of this Doctoral thesis indicate that males and females in adolescent populations have differences in knee stabilisation strategies and overall knee joint function. These findings further support the need for additional research considering risk factors such as, age/maturity-, sex-, and limb-dominance. This research will contribute to the tailoring of rehabilitation programs, thus providing an opportunity to improve the success rate of rehabilitation following ACL-injury among adolescents.

京都大学 / 新制・課程博士 / 博士(医学) / 甲第24829号 / 医博第4997号 / 新制||医||1067(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 森信, 暁雄, 教授 竹内, 理, 教授 濵﨑, 洋子 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Knee osteoarthritis (OA) is a progressive disease that ultimately requires patients to receive a total knee arthroplasty (TKA) to replace the damaged structures within the knee with an artificial joint. Surgeons have many options when selecting an appropriate implant. Patients want a TKA that feels 'normal' and allows them to perform most activities without pain, stiffness, and other residual symptoms. However, 20% of patients remain unsatisfied with their surgery, regardless. This thesis aimed to examine the effect of implant selection during TKA on knee biomechanical function during various ADLs. Several gaps were identified within the review of literature: 1) patient-reported outcome measures cannot differentiate between medial ball and socket (MBS) and posterior stabilized (PS) implants, 2) most biomechanical studies were performed only in postoperative patients, and 3) studies that compared MBS and PS implants were primarily focused on level walking conditions, and overlooked tasks that placed more demand on the knee joint. Twenty-eight individuals with severe knee OA were randomized to receive either an MBS (n=14) or PS implant. They completed a biomechanical assessment within one month and one year after TKA and were compared to 14 controls of similar age, sex, and body mass index. They performed a variety of tasks which explored three main areas: 1) examine the alterations in gait variability among individuals with OA following a TKA procedure using either a PS or MBS implant; 2) enhance the understanding of the post-operative effects of TKA with either MBS and PS implants on knee biomechanics and muscle activities during level walking, as well as more demanding tasks such as descending a ramp or staircase; 3) simulate the dynamic knee joint loads in post-operative TKA patients with either PS or MBS implants during closed-chain, bilateral tasks such as sit-to-stand. Initially, a series of studies were performed to develop a new test called waveform-level variance inequality test (eqvartest), which had not been previously utilized in the literature. This test was used to identify discrepancies in gait variability pre and post-TKA in the gait cycle. Following TKA, patients showed decreased variability in knee moment and power at single-limb support. Neither the MBS nor PS implant provided the same level of variability as the control group, demonstrating reduced knee joint stability. The MBS group had a gait pattern closer to the control group during level walking, whereas the PS group walked with a stiffer knee. However, during more demanding ADLs, the differences were less apparent. During ramp descent, knee joint stability issues became prominent as MBS and PS groups adopted a 'cautious gait pattern,' widening their base of support and stiffening their knee to reduce loading. During stair descent, the MBS implant provided increased stability as it required less muscle activity than the PS, requiring greater hamstring muscle activation. During sit-to-stand, MBS and PS groups favoured their non-operated knee as they had reduced total vertical, medial, and lateral KCF on their operated knee compared to their non-operated side. This may be due to compensatory strategies developed through the progression of knee OA and may increase the risk of developing knee OA on the non-operated limb. The outcomes of this thesis can assist clinicians in selecting the most appropriate implant for their patients and guide them in designing rehabilitation programs that can enhance patient function following TKA.

To alleviate the poor ergonomics which surgeons suffer during knee arthroscopy, a semi-robotic device with braking mechanism is created for intraoperative assistance. A slitted ball joint assembly is developed to transmit the clamping force to the arthroscope inside. Ball deformation and stress at various angles to the vertical and clamping forces is recorded through Abaqus Finite Element Analysis (FEA). Contact forces between the scope and inner surfaces of the ball is also computed in FEA at different clamping forces. The von Mises stress occurring in the ball joint is under the yield stress limit for polyethylene, and there is noticeable force preventing the scope from sliding along the ball through-hole under clamping. A prototype of this device is constructed for proof-of-concept.

The COVID-19 pandemic resulted in the cancellation of many hip and knee replacements, creating a backlog of patients on top of an existing long waiting list. To reduce wait lists with no financial burden, we aim to evaluate the possibility of leveraging our previous efficiency-improving work to add an additional case to a typical 4-joint day with no extra cost. To do this, 761 total operation days were analyzed from 2012 to 2019, capturing variables such as case number, success (completion of 4 cases before 3:45pm), and patient out of room time. Linear regression was used on 301 successful days to predict 5th cases, while overtime hours saved were calculated from the remaining unsuccessful days. Different cost distributions were then analyzed for a 77% 4-joint day success rate (our baseline), and a 100% 4-joint day success rate. Our predictions show that increasing performance to a 77% success rate can lead to approximately 35 extra cases per year at our institution, while a 100% success rate can produce 56 extra cases per year. Overall, this shows the extent of resources wasted by overtime costs, and the potential for their use in reducing wait times. Future work can explore optimal staffing procedures to account for these extra cases.

Background: Osteoarthritis (OA) is a common degenerative disease in elderly people, OA of the knee (KOA) makes up for a big part of all OA cases. Common KOA inconveniences are joint stiffness, pain and loss of muscle strength, which can have a negative impact on the quality of life. The OA process affects the kinematics of the knee joint and increases joint laxity, an impairment which can create more damage to the knee joint. Conservative treatment including exercise is the first option of choice in rehabilitation. Manual joint mobilization is another common treatment method which has effect on function and pain in patients with KOA. One muscle located in the hollow of the knee is the popliteal muscle and its function is to internally rotate the tibia, flex the knee joint and reduce ventral translation of the tibia; popliteal activity aims to maintain proper knee kinematics. Purpose: To investigate what effect myofascial release and exercise for the popliteus muscle have regarding pain, function and health related quality of life in people suffering from KOA. Method: A single subject experimental design study consisting of three participants with KOA was performed. The study started with a baseline phase measurement where the participants answered questionnaires about their pain, function and quality of life, followed by the intervention phase consisting of myofascial release (MFR) and exercise for the popliteal muscle. Result: There was not any concordant results for any of the outcome measurements even though each participant had positive changes in one or more of the different measurements mainly regarding pain, function in daily living or quality of life (QoL). Conclusion: MFR and exercise for the popliteus muscle might be effective as a treatment for people with KOA related inconveniences regarding mainly pain, function in daily living and QoL. Key words: Knee osteoarthritis, myofascial release, exercise, popliteus muscle.

Background: Osteoarthritis (OA) in the knee is one of the most common joint diseases in the world. The symptoms include local joint pain, joint stiffness, crepitation etc. Treatment follows national clinical guidelines which includes patient education, exercise and weight loss. Manual therapy can be used as an additional treatment and has shown a positive effect on pain, range of motion (ROM) and function but the method is not studied enough. Purpose: To investigate the effect of manual mobilization with the OMT Nordic System method as a complement to exercise and patient education for patients with knee OA on pain, Quality of Life (QoL) and ROM. Method: A Single subject experimental design study with 4 participants was conducted. Participants underwent a standardized patient education followed by a 6-week baseline of physical exercise, then a 3-week intervention phase which added manual therapy of the knee joint two times a week for the entire phase. The data was analysed regarding changes in both trend and level. Result: All participants had a significant positive change in level of pain and one participant had a positive change in trend. QoL varied among the participants, two had no change in level, one had a significantly positive change and one had a significantly negative change. Only one participant had a positive change of trend in QoL. ROM increased significantly in level in three out of four participants and the trend changed positively among two of the participants Conclusion: This study indicates that OMT Nordic system as a complement to physical exercise and patient education have a positive effect on pain and ROM in patients with knee OA in the short term. However, since not both level and trend were all over significant the result lacks in significance. Due to the study’s design the results should not be generalized on a group level. To be able to draw general conclusions further studies needs to investigate the effect of the OMT Nordic System with more participants and in different settings.