Publications by authors named "Jens Aaboe"

12 Publications

  • Page 1 of 1

Quadriceps-strengthening exercise and quadriceps and knee biomechanics during walking in knee osteoarthritis: A two-centre randomized controlled trial.

Clin Biomech (Bristol, Avon) 2018 11 15;59:199-206. Epub 2018 Sep 15.

The Parker Institute, Department of Rheumatology, Copenhagen University Hospital Bispebjerg-Frederiksberg, Copenhagen, Denmark.

Objective: To assess the effect of quadriceps strengthening on quadriceps muscle force, power, and work and tibio-femoral compressive loads during walking in adults with knee osteoarthritis.

Methods: Study design: Two-center, randomized, controlled trial.

Intervention: Patients with knee osteoarthritis were randomly allocated to quadriceps strengthening program (3 times weekly) or no attention control group.

Main Outcome Measures: Primary outcome was change from baseline in peak quadriceps force during walking at 12 weeks. Secondary outcomes included quadriceps power and work, knee compression forces during walking estimated with musculoskeletal modeling, muscle strength and pain and function. Outcomes were measured at baseline and 12 weeks.

Results: 30 patients were randomized to receive either training (n = 15) or no attention (n = 15). At follow-up, there were no statistical differences between groups for maximum quadriceps force, quadriceps positive power, negative work, and positive work, and knee compressive force. Maximum negative quadriceps power in early stance was statistically significantly increased 36% in the training group compared to the control group which was most likely partially a response to faster walking velocity at follow-up. Muscle strength and patient reported pain and function were improved in the training group compared to the control group.

Conclusions: Quadriceps strength training leads to increased muscle strength and improved symptomatic and functional outcomes but does not change quadriceps or knee joint biomechanics during walking. The biomechanical mechanism of improved health with strength training in knee osteoarthritis patients remains unknown. ClinicalTrials.gov Identifier: NCT01538407.
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http://dx.doi.org/10.1016/j.clinbiomech.2018.09.016DOI Listing
November 2018

Effects of supervised exercise compared to non-supervised exercise early after total hip replacement on patient-reported function, pain, health-related quality of life and performance-based function - a systematic review and meta-analysis of randomized controlled trials.

Clin Rehabil 2019 Jan 3;33(1):13-23. Epub 2018 Aug 3.

6 Elective Surgery Centre, Silkeborg Regional Hospital, Silkeborg, Denmark.

Background:: The rehabilitation after a total hip replacement varies in degree of supervision; however, it remains unknown whether supervised programmes are more effective than non-supervised.

Objective:: This study compared the effectiveness of supervised exercise compared to non-supervised home-based exercise after total hip replacement on patient-reported function, hip-pain, health-related quality of life and performance-based function.

Methods:: A systematic review and meta-analysis of randomized controlled trials investigating the effect of supervised exercise compared to non-supervised home-based exercise. An electronic search was performed in Medline, Embase and CINAHL on 14 March 2018. The methodological quality was assessed using the Cochrane Risk of Bias tool.

Results:: Seven studies were included with a total of 389 participants. A small and non-significant difference in favour of the supervised groups was found in patient-reported function (standardized mean difference (SMD) -0.22 (95% confidence interval (CI) -0.46 to 0.02)), hip-related pain (SMD -0.03 (95% CI -0.27 to 0.21)), health-related quality of life (mean difference (MD) -3.08 (95% CI -6.29 to 0.14)) and performance-based function (SMD -0.26 (95% CI -0.68 to 0.17)) at end of treatment and in patient-reported function (MD -1.31 (95% CI -3.79 to 1.16)) at the 6- to 12-month follow-up.

Limitations:: The literature search was systematic, but limited to three databases. The overall quality of evidence was downgraded to moderate due to lack of blinding in included studies.

Conclusion:: Supervised exercise was not significantly effective compared to non-supervised home-based exercise on patient-reported function, pain, health-related quality of life and performance-based function after primary total hip replacement.

Others:: PROSPERO registration number: CRD42017055604.
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http://dx.doi.org/10.1177/0269215518791213DOI Listing
January 2019

National Clinical Guidelines for non-surgical treatment of patients with recent onset low back pain or lumbar radiculopathy.

Eur Spine J 2018 01 20;27(1):60-75. Epub 2017 Apr 20.

, Hvidkildevej 62, 2400, København NV, Denmark.

Purpose: To summarise recommendations about 20 non-surgical interventions for recent onset (<12 weeks) non-specific low back pain (LBP) and lumbar radiculopathy (LR) based on two guidelines from the Danish Health Authority.

Methods: Two multidisciplinary working groups formulated recommendations based on the GRADE approach.

Results: Sixteen recommendations were based on evidence, and four on consensus. Management of LBP and LR should include information about prognosis, warning signs, and advise to remain active. If treatment is needed, the guidelines suggest using patient education, different types of supervised exercise, and manual therapy. The guidelines recommend against acupuncture, routine use of imaging, targeted treatment, extraforaminal glucocorticoid injection, paracetamol, NSAIDs, and opioids.

Conclusion: Recommendations are based on low to moderate quality evidence or on consensus, but are well aligned with recommendations from international guidelines. The guideline working groups recommend that research efforts in relation to all aspects of management of LBP and LR be intensified.
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http://dx.doi.org/10.1007/s00586-017-5099-2DOI Listing
January 2018

Effect of weight maintenance on symptoms of knee osteoarthritis in obese patients: a twelve-month randomized controlled trial.

Arthritis Care Res (Hoboken) 2015 May;67(5):640-50

The Parker Institute, Bispebjerg and Frederiksberg Hospital, The Capital Region of Copenhagen, Denmark.

Objective: To compare results of obese patients with knee osteoarthritis (OA) who, after an intensive weight loss regimen, received 1 year of either dietary support (D), a knee-exercise program (E), or "no attention" (C; control group).

Methods: We conducted a randomized, 2-phase, parallel-group trial. A total of 192 obese participants with knee OA were enrolled; the mean age was 62.5 years and 81% were women with a mean entry weight of 103.2 kg. In phase 1, all participants were randomly assigned to 1 of 3 groups and began a dietary regimen of 400-810 and 1,250 kcal/day for 16 weeks (2 8-week phases) to achieve a major weight loss. Phase 2 consisted of 52 weeks' maintenance in either group D, E, or C. Outcomes were changes from randomization in pain on a 100-mm visual analog scale, weight, and response according to the Outcome Measures in Rheumatology-Osteoarthritis Research Society International criteria.

Results: Mean weight loss for phase 1 was 12.8 kg. After 1 year on maintenance therapy, the D group sustained a lower weight (11.0 kg, 95% confidence interval [95% CI] 9.0, 12.8 kg) than those in the E (6.2, 95% CI 4.4, 8.1 kg) and C (8.2, 95% CI 6.4, 10.1 kg) groups (P = 0.002 by analysis of covariance [ANCOVA]). Adherence was low in the E group. All groups had statistically significant pain reduction (D: 6.1; E: 5.6; and C: 5.5 mm) with no difference between groups (P = 0.98 by ANCOVA). In each group 32 (50%), 26 (41%), and 33 (52%) participants responded to treatment in the D, E, and C groups, respectively, with no statistically significant difference in the number of responders (P = 0.41).

Conclusion: A significant weight reduction with a 1-year maintenance program improves knee OA symptoms irrespective of maintenance program.
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http://dx.doi.org/10.1002/acr.22504DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4657487PMC
May 2015

The Influence of Radiographic Severity on the Relationship between Muscle Strength and Joint Loading in Obese Knee Osteoarthritis Patients.

Arthritis 2011 10;2011:571519. Epub 2011 Apr 10.

Clinical Motor Function Laboratory, The Parker Institute, Frederiksberg Hospital, 2000 Frederiksberg, Denmark.

Objective. To investigate the relationship between knee muscle strength and the external knee adduction moment during walking in obese knee osteoarthritis patients and whether disease severity influences this relationship. Methods. This cross-sectional study included 136 elderly obese (BMI > 30) adults with predominant medial knee osteoarthritis. Muscle strength, standing radiographic severity as measured by the Kellgren and Lawrence scale, and the peak external knee adduction moment were measured at self-selected walking speed. Results. According to radiographic severity, patients were classified as "less severe" (KL 1-2, N = 73) or "severe" (KL 3-4, N = 63). A significant positive association was demonstrated between the peak knee adduction moment and hamstring muscle strength in the whole cohort (P = .047). However, disease severity did not influence the relationship between muscle strength and dynamic medial knee joint loading. Severe patients had higher peak knee adduction moment and more varus malalignment (P < .001). Conclusion. Higher hamstring muscle strength relates to higher estimates of dynamic knee joint loading in the medial compartment. No such relationship existed for quadriceps muscle strength. Although cross sectional, the results suggest that hamstrings function should receive increased attention in future studies and treatments that aim at halting disease progression.
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http://dx.doi.org/10.1155/2011/571519DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3200076PMC
November 2011

The relationship between pain and dynamic knee joint loading in knee osteoarthritis varies with radiographic disease severity. A cross sectional study.

Knee 2012 Aug 11;19(4):392-8. Epub 2011 Aug 11.

Clinical Motor Function Laboratory, The Parker Institute, Frederiksberg Hospital, Ndr. Fasanvej 57, DK-2000 Frederiksberg C, Denmark.

Objective: In a cross sectional study, we investigated the relationships between knee pain and mechanical loading across the knee, as indicated by the external knee adduction moment (KAM) during walking in patients with symptomatic knee OA who were distinguished by different radiographic disease severities.

Methods: Data from 137 symptomatic medial knee OA patients were used. Based on Kellgren/Lawrence (K/L) grading, the patients were divided into radiographically less severe (K/L ≤ 2, n=68) or severe (K/L>2, n=69) medial knee OA. Overall knee pain was rated on a 10 cm visual analog scale, and peak KAM and KAM impulses were obtained from gait analyses. Mixed linear regression analyses were performed with KAM variables as the outcome, and pain and disease severity as independent variables, adjusting for age, gender, and walking speed.

Results: In adjusted analyses, less severe patients demonstrated negative relationships between pain intensities and dynamic loading. The severe patient group showed no relationship between pain intensity and peak KAM, and a positive relationship between pain intensity and KAM impulse.

Conclusion: In radiographically less severe knee OA, the negative relationships between pain intensity and dynamic knee joint loading indicate a natural reaction to pain, which will limit the stress on the joint. In contrast, either absent or positive relationships between pain and dynamic loading in severe OA may lead to overuse and accelerated disease progression. These findings may have a large potential interest for strategies of treatment in knee OA.
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http://dx.doi.org/10.1016/j.knee.2011.07.003DOI Listing
August 2012

The association between submaximal quadriceps force steadiness and the knee adduction moment during walking in patients with knee osteoarthritis.

J Orthop Sports Phys Ther 2011 Aug 12;41(8):592-9. Epub 2011 Jul 12.

Clinical Motor Function Laboratory, The Parker Institute, Frederiksberg Hospital, Frederiksberg, Denmark.

Study Design: Cross-sectional study.

Objectives: To investigate the relationship between quadriceps force steadiness and knee adduction moment during walking in patients with knee osteoarthritis (OA).

Background: Studies have shown that quadriceps force steadiness is impaired in patients with knee OA. Furthermore, patients with knee OA, compared to healthy controls, have also demonstrated a significantly higher external knee adduction moment during walking. However, no studies have examined the relationship between quadriceps force steadiness and the peak knee adduction moment during walking in this population.

Methods: Forty-one patients with knee OA (34 females and 7 males) were included in the study. Submaximal isometric quadriceps force steadiness was measured during a force target-tracking task. Peak knee adduction moments during ambulation were measured using a 3-dimensional gait analysis system, and knee pain was assessed using the Knee Injury and Osteoarthritis Outcome Score (KOOS) pain subscale and a visual analog scale.

Results: Regression analyses showed that quadriceps force steadiness did not predict the peak knee adduction moment (adjusted R2 = 0.05, P = .41). Inclusion of covariates did not change the outcome.

Conclusion: No statistically significant association between submaximal isometric quadriceps force steadiness and peak knee external adduction moments during walking was found. It could be speculated that submaximal isometric quadriceps muscle force steadiness and knee joint loads during walking represent 2 distinctive pathways and may have independent influences on knee OA pathogenesis.
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http://dx.doi.org/10.2519/jospt.2011.3481DOI Listing
August 2011

Experimental knee pain reduces muscle strength.

J Pain 2011 Apr 13;12(4):460-7. Epub 2010 Dec 13.

Clinical Motor Function Laboratory, The Parker Institute, Frederiksberg Hospital, Frederiksberg, Denmark.

Unlabelled: Pain is the principal symptom in knee pathologies and reduced muscle strength is a common observation among knee patients. However, the relationship between knee joint pain and muscle strength remains to be clarified. This study aimed at investigating the changes in knee muscle strength following experimental knee pain in healthy volunteers, and if these changes were associated with the pain intensities. In a crossover study, 18 healthy subjects were tested on 2 different days. Using an isokinetic dynamometer, maximal muscle strength in knee extension and flexion was measured at angular velocities 0, 60, 120, and 180 degrees/second, before, during, and after experimental pain induced by injections of hypertonic saline into the infrapatellar fat pad. On a separate day, isotonic saline injections were used as control condition. The pain intensity was assessed on a 0- to 100-mm visual analogue scale. Knee pain reduced the muscle strength by 5 to 15% compared to the control conditions (P < .001) in both knee extension and flexion at all angular velocities. The reduction in muscle strength was positively correlated to the pain intensity. Experimental knee pain significantly reduced knee extension and flexion muscle strength indicating a generalized muscle inhibition augmented by higher pain intensities.

Perspective: This study showed that knee joint pain has a significant impact on muscle function. The findings provide evidence of a direct inhibition of muscle function by joint pain, implying that rehabilitative strengthening exercises may be antagonized by joint pain.
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http://dx.doi.org/10.1016/j.jpain.2010.10.004DOI Listing
April 2011

Motor responses to experimental Achilles tendon pain.

Br J Sports Med 2011 Apr 11;45(5):393-8. Epub 2010 Jun 11.

Clinical Motor Function Laboratory, The Parker Institute, Frederiksberg Hospital, Denmark.

Background: Achilles tendinopathies are characterised by pain and reduced function, and heavy-load exercises have been shown to be effective in the treatment of painful chronic Achilles tendinopathies. However, basic information is needed on how the biomechanics and neuromuscular control of the exercise are affected by Achilles tendon pain.

Objective: The authors aimed to determine the effects of experimental Achilles tendon pain on motor function during one-legged weight bearing ankle plantar and dorsal flexion exercises.

Methods: In a crossover study, with 16 healthy subjects tested on two different days separated by 1 week, three-dimensional ground reaction forces, ankle joint kinematics and surface electromyography (EMG) of the lower leg muscles were recorded during one-legged full weight-bearing ankle plantar (concentric) and dorsal (eccentric) flexion exercises. Measurements were done before, during and after either experimental Achilles tendon pain or a non-painful control condition. Pain was induced by intratendinous injections of hypertonic saline with isotonic saline injections as control. Joint kinematics, ground reaction force frequency contents and average EMG amplitudes were calculated.

Results: Compared with the control condition experimental Achilles tendon pain reduced the EMG activity in agonistic, synergistic and antagonistic muscles, and increased the ground reaction force frequency content around 10 Hz, during both eccentric and concentric movement phases.

Conclusions: These data show that experimental Achilles tendon pain causes widespread and reduced motor responses with functional effects on the ground reaction force.
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http://dx.doi.org/10.1136/bjsm.2010.072561DOI Listing
April 2011

Gait changes in patients with knee osteoarthritis are replicated by experimental knee pain.

Arthritis Care Res (Hoboken) 2010 Apr;62(4):501-9

Clinical Motor Function Laboratory, Frederiksberg Hospital, Ndr. Fasanvej 57, Frederiksberg, Denmark.

Objective: Medial knee osteoarthritis (OA) is characterized by pain and associated with abnormal knee moments during walking. The relationship between knee OA pain and gait changes remains to be clarified, and a better understanding of this link could advance the treatment and prevention of disease progression. This study investigated changes in knee moments during walking following experimental knee pain in healthy volunteers, and whether these changes replicated the joint moments observed in medial knee OA patients.

Methods: In a crossover study, 34 healthy subjects were tested on 3 different days; gait analyses were conducted before, during, and after pain induced by hypertonic saline injections (0.75 ml) into the infrapatellar fat pad. Isotonic saline and sham injections were used as control conditions. Peak moments in frontal and sagittal planes were analyzed. The results were compared with data from 161 medial knee OA patients. The patients were divided into less severe OA and severe OA categories, which was based on radiographic disease severity of the medial compartment.

Results: Experimental knee pain led to reduced peak moments in the frontal and sagittal planes in the healthy subjects, which were similar to the patterns observed in less severe OA patients while walking at the same speed.

Conclusion: In healthy subjects, pain was associated with reductions in knee joint moments during walking in a manner similar to less severe knee OA patients. The experimental model may be used to study mechanically-driven knee OA progression and preventive measures against abnormal joint loading in knee OA.
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http://dx.doi.org/10.1002/acr.20033DOI Listing
April 2010

Biomechanical characteristics of the eccentric Achilles tendon exercise.

J Biomech 2009 Dec 22;42(16):2702-7. Epub 2009 Sep 22.

Clinical Motor Function Laboratory, The Parker Institute, Frederiksberg Hospital, Denmark.

Background: Eccentric exercise has been shown to provide good short-term clinical results in the treatment of painful mid-portion chronic Achilles tendinopathies. However, the mechanisms behind the positive effects of eccentric rehabilitation regimes are not known, and research into the biomechanics of the exercise may improve our understanding.

Methods: Sixteen healthy subjects performed one-legged full weight bearing ankle plantar and dorsiflexion exercises during which three-dimensional ground reaction forces (GRF), ankle joint kinematics and surface electromyography (EMG) of the lower leg muscles were recorded. Joint kinematics, GRF frequency contents, average EMG amplitudes, and Achilles tendon loads were calculated.

Findings: The eccentric movement phase was characterized by a higher GRF frequency content in the 8-12 Hz range, and reduced EMG activity in the lower leg muscles. No differences in Achilles tendon loads were found.

Interpretation: This descriptive study demonstrates differences in the movement biomechanics between the eccentric and concentric phases of one-legged full weight bearing ankle dorsal and plantar flexion exercises. In particular, the findings imply that although the tendon loads are similar, the tendon is vibrated at higher frequencies during the eccentric phase than during the concentric phases. This study provides data that may explain the mechanisms behind the effectiveness of eccentric exercises used in the treatment of Achilles tendinopathies.
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http://dx.doi.org/10.1016/j.jbiomech.2009.08.009DOI Listing
December 2009

Experimentally reduced hip abductor function during walking: Implications for knee joint loads.

J Biomech 2009 Jun 14;42(9):1236-40. Epub 2009 Apr 14.

Clinical Motor Function Laboratory, The Parker Institute, Frederiksberg Hospital, Ndr. Fasanvej 57, Frederiksberg, Denmark.

Hip and knee functions are intimately connected and reduced hip abductor function might play a role in development of knee osteoarthritis (OA) by increasing the external knee adduction moment during walking. The purpose of this study was to test the hypothesis that reduced function of the gluteus medius (GM) muscle would lead to increased external knee adduction moment during level walking in healthy subjects. Reduced GM muscle function was induced experimentally, by means of intramuscular injections of hypertonic saline that produced an intense short-term muscle pain and reduced muscle function. Isotonic saline injections were used as non-painful control. Fifteen healthy subjects performed walking trials at their self-selected walking speed before and immediately after injections, and again after 20 min of rest, to ensure pain recovery. Standard gait analyses were used to calculate three-dimensional trunk and lower extremity joint kinematics and kinetics. Surface electromyography (EMG) of the glutei, quadriceps, and hamstring muscles were also measured. The peak GM EMG activity had temporal concurrence with peaks in frontal plane moments at both hip and knee joints. The EMG activity in the GM muscle was significantly reduced by pain (-39.6%). All other muscles were unaffected. Peaks in the frontal plane hip and knee joint moments were significantly reduced during pain (-6.4% and -4.2%, respectively). Lateral trunk lean angles and midstance hip joint adduction and knee joint extension angles were reduced by 1 degrees . Thus, the gait changes were primarily caused by reduced GM function. Walking with impaired GM muscle function due to pain significantly reduced the external knee adduction moment. This study challenge the notion that reduced GM function due to pain would lead to increased loads at the knee joint during level walking.
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http://dx.doi.org/10.1016/j.jbiomech.2009.03.021DOI Listing
June 2009
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