The purpose of this study is to create an accurate experimental database for the passive (in vitro)freedom-of-motion characteristics of the human knee joint on a subject to subject basis, suitable for the verification and enhancement of mathematical knee-joint models. Knee-joint specimens in a six degree-of-freedom motion rig are moved through flexion under several combinations of external loads, including tibial torques, axial forces and AP-forces. Euler rotation angles and translation vectors, describing the relative, spatial motions of the joint are measured using an accurate Roentgen Stereo Photogrammetric system. Conceptually the joint is considered as a two degrees-of-freedom of motion mechanism (flexion-tibial rotation), whereby the limits of internal and external tibial rotation are defined at torques of ± 3 Nm. The motion pathways along these limits are denned as the envelopes of passive knee joint motion. It is found that these envelope pathways are consistent and hardly influenced by additional axial forces up to 300 N and AP-forces of 30 N. Within the envelope of motion, however, the motion patterns are highly susceptible to small changes in the external load configuration. It is shown that the external tibial rotation during extension ('screw-home mechanism') is not an obligatory effect of the passive joint characteristics, but a direct result of the external loads. Anatomical differences notwithstanding, the inter-individual discrepancies in the motion patterns of the four specimens tested, showed to be relatively small in a qualitative sense. Quantitative differences can be explained by small differences in the alignment of the coordinate systems relative to the joint anatomy and by differences in rotatory laxity.
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BACKGROUND: Patients with knee osteoarthritis can adapt their gait to unload the most painful knee joint in order to try to reduce pain and improve physical function. However, these gait adaptations can cause higher loads on the contralateral joints. The aim of the study was to investigate the interlimb differences in knee and hip frontal plane moments during gait in patients with knee osteoarthritis and in healthy controls.METHODS: Forty patients with knee osteoarthritis and 19 healthy matched controls were measured during comfortable treadmill walking. Frontal plane joint moments were obtained of both hip and knee joints. Differences in interlimb moments within each group were assessed using statistical parametric mapping and discrete gait parameters.FINDINGS: No interlimb differences were observed in patients with knee osteoarthritis and control subjects at group level. Furthermore, the patients presented similar interlimb variability as the controls. In a small subgroup (n = 12) of patients, the moments in the most painful knee were lower than in the contralateral knee, while the other patients (n = 28) showed higher moments in the most painful knee compared to the contralateral knee. However, no interlimb differences in the hip moments were observed within the subgroups.INTERPRETATION: Patients with knee osteoarthritis do not have interlimb differences in knee and hip joint moments. Patients and healthy subjects demonstrate a similar interlimb variability in the moments of the lower extremities. In this context, differences in knee pain in patients with knee osteoarthritis did not induce any interlimb differences in the frontal plane knee and hip moments.
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Background The gait modification strategies Trunk Lean and Medial Thrust have been shown to reduce the external knee adduction moment (EKAM) in patients with knee osteoarthritis which could contribute to reduced progression of the disease. Which strategy is most optimal differs between individuals, but the underlying mechanism that causes this remains unknown. Research question Which gait parameters determine the optimal gait modification strategy for individual patients with knee osteoarthritis? Methods Forty-seven participants with symptomatic medial knee osteoarthritis underwent 3-dimensional motion analysis during comfortable gait and with two gait modification strategies: Medial Thrust and Trunk Lean. Kinematic and kinetic variables were calculated. Participants were then categorized into one of the two subgroups, based on the modification strategy that reduced the EKAM the most for them. Multiple logistic regression analysis with backward elimination was used to investigate the predictive nature of dynamic parameters obtained during comfortable walking on the optimal modification gait strategy. Results For 68.1 % of the participants, Trunk Lean was the optimal strategy in reducing the EKAM. Baseline characteristics, kinematics and kinetics did not differ significantly between subgroups during comfortable walking. Changes to frontal trunk and tibia angles correlated significantly with EKAM reduction during the Trunk Lean and Medial Thrust strategies, respectively. Regression analysis showed that MT is likely optimal when the frontal tibia angle range of motion and peak knee flexion angle in early stance during comfortable walking are high (R2Nagelkerke = 0.12). Significance Our regression model based solely on kinematic parameters from comfortable walking contained characteristics of the frontal tibia angle and knee flexion angle. As the model explains only 12.3 % of variance, clinical application does not seem feasible. Direct assessment of kinetics seems to be the most optimal strategy for selecting the most optimal gait modification strategy for individual patients with knee osteoarthritis.
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Background: The modified painDETECT questionnaire (PDQ) is a self-reported questionnaire to discriminatebetween nociceptive and neuropathic-like pain in patients with knee/hip osteoarthritis (OA). This studyaims to assess the structural and construct validity of this questionnaire.Methods: Confirmatory factor analysis and hypothesis-testing was used. For 168 patients, predefinedhypotheses were formulated on the correlation between the modified painDETECT and several otherquestionnaires, and in a subsample of 46 with pain pressure thresholds (PPTs).Results: Two principal components were confirmed. The pain pattern item did not load on any component.Eighty per cent of the hypotheses on the correlation between modified PDQ and the questionnaireswere met, as were 50% concerning PPTs measurements.Conclusions: This study is the first to assess structural and construct validity of the modified PDQ knee/hip by using factor analysis and hypothesis-testing. This questionnaire seems to reflect neuropathic-like pain symptoms experienced by hip/knee OA-patients with adequate validity. The item on pain patternmight not reflect the construct. More than 75% of the predefined hypotheses regarding the modified PDQ and the other questionnaires were met. Only 50% of the hypotheses on PPTs measurements were met, probably due to heterogeneity and limited size of this subsample.
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Purpose: The etiology of pain in osteoarthritis (OA) is complex andmultifactorial. A growing number of studies suggest that modificationof pain-transmission in the peripheral and central nervous system,leading to sensitization, plays a role in OA pain. Sensitization seems tobe associated with neuropathic pain-like symptoms and assessment ofthese symptoms can help to identify patients who could benefit fromadditional treatment options. Several questionnaires are available todistinguish neuropathic from nociceptive pain symptoms. The modifiedpainDETECT questionnaire (mPDQ) is a self-reported questionnairedeveloped to discriminate between nociceptive- and possible/likelyneuropathic pain in knee OA patients. Recently the mPDQ was translatedinto Dutch and adjusted to also fit hip OA patients. The aim of thisstudy was to assess the validity of the mPDQ-NL in patients with hip orknee OA.Methods: Primary hip and knee OA patients were recruited from threeDutch hospitals. Based on previous research, confirmatory factor analysisfor two principal components was performed to assess structuralvalidity. Construct validity (both convergent and divergent) wasassessed using hypothesis testing. Predefined hypotheses were formulatedconcerning the correlation between the mPDQ-NL and theSelf-reported Leeds Assessment of Neuropathic Symptoms and Signs (SLANSS),subscales of the Knee injury and Osteoarthritis Outcome score/Hip disability and Osteoarthritis Outcome Score (KOOS/HOOS), VisualAnalogue Scale for pain (VAS pain), and subscales of the RAND-36health survey (RAND-36). According to the COSMIN criteria, constructvalidity of a questionnaire is sufficient if 75% of predefined hypothesesare met. Additionally, convergent validity was assessed with blunt PainPressure Thresholds (PPTs) in a subsample of participants. A reducedPPT is a somatosensory abnormality that is considered an indication ofsensitization in OA. Therefore it was expected that reduction of PPTswas associated with higher mPDQ scores.Results: 168 participants were included. PPT measurements wereperformed in a sample of 46 participants. Factor analysis confirmed twoprincipal components. The items that loaded on the first componentcould be described as “evoked neuropathic sensations”, the items thatloaded on the second component as “spontaneous neuropathic sensations”.However there were two items that substantially loaded on bothcomponents. The item regarding pain pattern did not load on anycomponent. Considering construct analysis, 80% of the predefinedhypotheses concerning the correlation between mPDQ and self-reportedquestionnaires were met. Considering the correlation with PPTmeasurements, 50% of the predefined hypotheses were met.Conclusions: The mPDQ-NL seems to adequately reflect neuropathicpain-like symptoms experienced by hip and knee OA patients. Concerningstructural validity, two determinative components seem to bepresent, in line with previous research. However, one particular itemregarding pain pattern might not reflect the construct of neuropathicpain-like symptoms in hip or knee OA. Therefore, when using the mPDQin hip or knee OA patients, it might be considered to skip this particularitem. Construct validity can be considered sufficient, with over 75% ofthe predefined hypotheses regarding correlation between the mPDQNLand other questionnaires were met. However, only 50% of the hypotheses concerning PPT measurements were met, probably due toheterogeneity and limited sample size of this subgroup. To ourknowledge, this study is the first to assess the structural validity of themPDQ knee and hip by using factor analysis and to assess constructvalidity using elaborate hypothesis testing as proposed by the COSMINguidelines.
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Introduction: Cutting is an important skill in team-sports, but unfortunately is also related to non-contact ACL injuries. The purpose was to examine knee kinetics and kinematics at different cutting angles. Material and methods: 13 males and 16 females performed cuts at different angles (45 , 90 , 135 and 180 ) at maximum speed. 3D kinematics and kinetics were collected. To determine differences across cutting angles (45 , 90 , 135 and 180 ) and sex (female, male), a 4 2 repeated measures ANOVA was conducted followed by post hoc comparisons (Bonferroni) with alpha level set at a 0.05 a priori. Results: At all cutting angles, males showed greater knee flexion angles than females (p < 0.01). Also, where males performed all cutting angles with no differences in the amount of knee flexion 42.53 ± 8.95 , females decreased their knee flexion angle from 40.6 ± 7.2 when cutting at 45 to 36.81 ± 9.10 when cutting at 90 , 135 and 180 (p < 0.01). Knee flexion moment decreased for both sexes when cutting towards sharper angles (p < 0.05). At 90 , 135 and 180 , males showed greater knee valgus moments than females. For both sexes, knee valgus moment increased towards the sharper cut- ting angles and then stabilized compared to the 45 cutting angle (p < 0.01). Both females and males showed smaller vGRF when cutting to sharper angles (p < 0.01). Conclusion: It can be concluded that different cutting angles demand different knee kinematics and kinet- ics. Sharper cutting angles place the knee more at risk. However, females and males handle this differ- ently, which has implications for injury prevention.
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Background: Osteoarthritis is one of the most common chronic joint diseases, mostly affecting the knee or hip through pain, joint stiffness and decreased physical functioning in daily life. Regular physical activity (PA) can help preserve and improve physical functioning and reduce pain in patients with osteoarthritis. Interventions aiming to improve movement behaviour can be optimized by tailoring them to a patients' starting point; their current movement behaviour. Movement behaviour needs to be assessed in its full complexity, and therefore a multidimensional description is needed. Objectives: The aim of this study was to identify subgroups based on movement behaviour patterns in patients with hip and/or knee osteoarthritis who are eligible for a PA intervention. Second, differences between subgroups regarding Body Mass Index, sex, age, physical functioning, comorbidities, fatigue and pain were determined between subgroups. Methods: Baseline data of the clinical trial 'e-Exercise Osteoarthritis', collected in Dutch primary care physical therapy practices were analysed. Movement behaviour was assessed with ActiGraph GT3X and GT3X+ accelerometers. Groups with similar patterns were identified using a hierarchical cluster analysis, including six clustering variables indicating total time in and distribution of PA and sedentary behaviours. Differences in clinical characteristics between groups were assessed via Kruskall Wallis and Chi2 tests. Results: Accelerometer data, including all daily activities during 3 to 5 subsequent days, of 182 patients (average age 63 years) with hip and/or knee osteoarthritis were analysed. Four patterns were identified: inactive & sedentary, prolonged sedentary, light active and active. Physical functioning was less impaired in the group with the active pattern compared to the inactive & sedentary pattern. The group with the prolonged sedentary pattern experienced lower levels of pain and fatigue and higher levels of physical functioning compared to the light active and compared to the inactive & sedentary. Conclusions: Four subgroups with substantially different movement behaviour patterns and clinical characteristics can be identified in patients with osteoarthritis of the hip and/or knee. Knowledge about these subgroups can be used to personalize future movement behaviour interventions for this population.
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PURPOSE: It has been reported that there is no correlation between anterior tibia translation (ATT) in passive and dynamic situations. Passive ATT (ATTp) may be different to dynamic ATT (ATTd) due to muscle activation patterns. This study aimed to investigate whether muscle activation during jumping can control ATT in healthy participants.METHODS: ATTp of twenty-one healthy participants was measured using a KT-1000 arthrometer. All participants performed single leg hops for distance during which ATTd, knee flexion angles and knee flexion moments were measured using a 3D motion capture system. During both tests, sEMG signals were recorded.RESULTS: A negative correlation was found between ATTp and the maximal ATTd (r = - 0.47, p = 0.028). An N-Way ANOVA showed that larger semitendinosus activity was seen when ATTd was larger, while less biceps femoris activity and rectus femoris activity were seen. Moreover, larger knee extension moment, knee flexion angle and ground reaction force in the anterior-posterior direction were seen when ATTd was larger.CONCLUSION: Participants with more ATTp showed smaller ATTd during jump landing. Muscle activation did not contribute to reduce ATTd during impact of a jump-landing at the observed knee angles. However, subjects with large ATTp landed with less knee flexion and consequently showed less ATTd. The results of this study give information on how healthy people control knee laxity during jump-landing.LEVEL OF EVIDENCE: III.
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Het ondergaan van een eenzijdige beenamputatie is een drastische chirurgische ingreep. Mensen, die na een amputatie in staat zijn om te lopen met een prothese, zijn functioneel onafhankelijker, en hebben een hogere kwaliteit van leven dan mensen die in een rolstoel belanden. Het is daarom niet verrassend dat het herwinnen van de oopvaardigheid één van de voornaamste doelen is tijdens de revalidatie. Doel van het onderzoek was om inzicht te krijgen in de factoren die het herwinnen en onderhouden van de loopvaardigheid van mensen na een beenamputatie beïnvloeden. Gebaseerd op de resultaten van het onderzoek kan geconcludeerd worden dat de fysieke capaciteit hierbij een belangrijke rol speelt. Een relatief kleine verbetering in de capaciteit kan al resulteren in significante en klinisch relevante verbeteringen. Hoewel geavanceerde prothesen de mechanische belasting van het lopen met een beenprothese verminderen, kan een ineffectieve balanscontrole deze positieve resultaten weer tenietdoen. ABSTRACT Undergoing a lower limb amputation is a life-changing surgery. The ability to walk greatly influences the subject's functional independence and quality of life. Not surprisingly, regaining walking ability is one of the primary goals during prosthetic rehabilitation. The primary aim of the research performed was to enhance our understanding of some of the factors that influence the ability to regain and maintain walking after a unilateral lower limb amputation. Based on the results we can deduce that a person's physical capacity plays an important role in their walking ability. Relatively small improvements in capacity could lead to significant and clinically relevant improvements in people's walking ability. Furthermore, results show that sophisticated prosthetic feet can reduce the mechanical load experienced when walking with a prosthesis. Interestingly, inefficient balance control strategies can undo any positive effect of these prostheses.
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Integrating physical therapy sessions and an online application (e-Exercise) might support people with hip osteoarthritis (OA), knee OA, or both (hip/knee OA) in taking an active role in the management of their chronic condition and may reduce the number of physical therapy sessions. The objective of this study was to investigate the short- and long-term effectiveness of e-Exercise compared to usual physical therapy in people with hip/knee OA. The design was a prospective, single-blind, multicenter, superiority, cluster-randomized controlled trial. e-Exercise is a 3-month intervention in which about 5 face-to-face physical therapy sessions were integrated with an online application consisting of graded activity, exercise, and information modules. Usual physical therapy was conducted according to the Dutch physical therapy guidelines on hip and knee OA. Primary outcomes, measured at baseline after 3 and 12 months, were physical functioning and free-living physical activity. Secondary outcome measures were pain, tiredness, quality of life, self-efficacy, and the number of physical therapy sessions.
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