Quadriceps Femoris and Hamstring Muscle Function in a Person With an Unstable Knee
TL;DR: Muscle inhibition decreased and maximal isometric knee flexion and extension torques increased during the 12-week training period and a 50% decrease in the maximum knee extensor moment and an increase in walking speed was demonstrated.
Abstract: Background and Purpose. The purpose of this case report is to describe the evaluation, treatment, and short-term outcome for an individual with chronic, progressively worsening instability of the knee during gait associated with anterior cruciate ligament (ACL) insufficiency. Case Description. The patient was a 34-year-old man who sustained bilateral ACL injuries. Subsequently, an autograft reconstruction of the left knee ACL was performed. Eight months post-reconstruction, the left knee was unstable despite bracing. Gait analysis and tests to determine the presence of muscle inhibition were performed prior to and after 12 weeks of training. Isometric torque of the knee extensors and flexors was measured with the knee in 90 degrees of flexion. A training program primarily consisted of electromyographic biofeedback during thigh muscle exercises, balance exercises, and gait. Outcomes. Muscle inhibition decreased and maximal isometric knee flexion and extension torques increased during the 12-week training period. Gait analysis demonstrated a 50% decrease in the maximum knee extensor moment and an increase in walking speed. Discussion. Selected gait variables, torque production, and muscle inhibition may change in a person with an unstable knee. The measurement of variables that have previously been documented as mechanisms of knee instability during walking allows for the selection of a specific treatment approach.
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TL;DR: The purpose of this article is to present a guide, accompanied by an inclusive reference list, for the use and interpretation of kinesiologic electromyographic data, intended as a tool for students, educators, clinicians, and beginning researchers who use and interpret kinesicographic data.
Abstract: Physical therapists are among the most common users of electromyography as a method for understanding function and dysfunction of the neuromuscular system. However, there is no collection of references or a source that provides an overview or synthesis of information that serves to guide either the user or the consumer of electromyography and the data derived. Thus, the purpose of this article is to present a guide, accompanied by an inclusive reference list, for the use and interpretation of kinesiologic electromyographic data. The guide is divided into 4 major sections: collecting, managing, normalizing, and analyzing kinesiologic electromyographic data. In the first of these sections, the issues affecting data collection with both indwelling and surface electrodes are discussed. In the second section, data management through alternative forms of data processing is addressed. In the third section, various reasons and procedures for data normalization are discussed. The last section reviews qualitative descriptors once used as the only means of analyzing data, then focuses on more quantitative procedures that predominate today. The guide is intended as a tool for students, educators, clinicians, and beginning researchers who use and interpret kinesiologic electromyographic data. Modifications will likely be needed as alternative forms of collecting, managing, normalizing, and analyzing electromyographic data are proposed, used in various settings, and reported in the literature.
512Â citations
TL;DR: In this paper, the authors review the current literature and critically discuss current rehabilitation approaches to restore quadriceps muscle function after ACL reconstruction, and identify strategies to minimize the muscle weakness following ACL injury and reconstruction.
366Â citations
TL;DR: Known neuromuscular consequences of ACL injury and reconstruction are reviewed and changes in somatosensation, muscle activation, muscle strength, atrophy, balance, biomechanics, and patient-oriented outcomes are discussed.
233Â citations
TL;DR: This study systematically examined the incidence and severity of quadriceps voluntary activation failure in both lower extremities after acute anterior cruciate ligament injury and found that there would be no difference in inhibition by gender.
142Â citations
TL;DR: Since participants in this study were free of knee joint pathology, it is possible that they did not have the capacity to allow for large changes in quadriceps muscle activation to occur, and this effect was not present after the 20 min interval.
84Â citations
Cites background from "Quadriceps Femoris and Hamstring Mu..."
...Individuals with knee joint pathology typically have some level of quadriceps inhibition (Stratford, 1982; SnyderMackler et al., 1994; Maitland et al., 1999; Suter et al., 1999, 2000; Urbach et al., 1999, 2001; Hopkins et al., 2001; Palmieri et al., 2003, 2004; Williams et al., 2003; Chmielewski et al., 2004) which may allow for greater changes in quadriceps activation to occur following intervention....
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...Individuals with knee joint pathology typically have some level of quadriceps inhibition (Stratford, 1982; SnyderMackler et al., 1994; Maitland et al., 1999; Suter et al., 1999, 2000; Urbach et al., 1999, 2001; Hopkins et al., 2001; Palmieri et al., 2003, 2004; Williams et al., 2003; Chmielewski et…...
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TL;DR: The results demonstrate that with the subjects walking at their natural or preferred spped, the gait variables are quite repeatable, and suggest that it may be reasonable to base significant clinical decisions on the results of a single gait evaluation.
1,415Â citations
TL;DR: Hours per year of sports participation and levels of sports par ticipation decreased in all groups and factors that correlated with patients who had late surgery for a meniscal tear or an ACL reconstruction were preinjury hours of sports Participation, arthrometer surements, and patient age.
Abstract: We followed 292 patients who had sustained an acute traumatic hemarthrosis for a mean of 64 months. The KT-1000 arthrometer measurements within 90 days of injury revealed the injured knee was stable in 56 pa tients and unstable in 236. Forty-five unstable patients had an ACL reconstruction within 90 days of injury. Sur gical procedures performed >90 days after injury in cluded ligament reconstruction in 46 patients. Factors that correlated with patients who had late surgery for a meniscal tear or an ACL reconstruction (P < 0.05) were preinjury hours of sports participation, arthrometer mea surements, and patient age.Follow-up data are presented for the patients divided into four groups: I, early stable, no reconstruction; II, early unstable, no reconstruction; III, early recon struction; and IV, late reconstruction. No patient changed occupation because of the knee injury. Hours per year of sports participation and levels of sports par ticipation decreased in all groups. Joint arthrosis was documented by ...
1,175Â citations
TL;DR: The antagonist muscles (hamstrings) were clearly demonstrated to assume the role of joint stabilizers in the patient who has a deficient ACL, and the importance of an appropriate muscle-conditioning rehabilitation program in such a patient is substantiated.
Abstract: The synergistic action of the ACL and the thigh muscles in maintaining joint stability was studied experimentally. The EMG from the quadriceps and hamstring muscle groups was recorded and analyzed in three separate experimental procedures in which the knee was stressed. The test revealed that direct stress of the ACL has a moderate inhibitory effect on the quadriceps, but simultaneously it directly excites the hamstrings. Similar responses were also obtained in patients with ACL damage during loaded knee extension with tibia subluxation, indicating that an alternative reflex arc unrelated to ACL receptors was available to maintain joint integrity.The antagonist muscles (hamstrings) were clearly demonstrated to assume the role of joint stabilizers in the patient who has a deficient ACL. The importance of an appropriate muscle-conditioning rehabilitation program in such a patient is substantiated.
812Â citations
TL;DR: In 10 subjects with normal knees, an experimentally produced knee fusion was found to result in profound inhi bition of reflexly evoked quadriceps contraction, and the anatomical and physiologic data are discussed.
Abstract: This investigation utilized gross dissections, histolog ical preparations, and neurophysiologic experiments to gain an improved understanding of the innervation of the human knee. Anatomical illustrations represent the findings of dissections of 15 fresh amputation specimens. Neurohistologic preparations using silver staining techniques demonstrate the rich innervation of the soft tissues of the knee, and a variety of spe cialized receptors are identified. In 10 subjects with normal knees, an experimentally produced knee ef fusion of 60 cc was found to result in profound inhi bition of reflexly evoked quadriceps contraction. Clin ical implications of the anatomical and physiologic data are discussed.
767Â citations
TL;DR: In the 53 patients arthroscoped who had complete ACL tears, the anterior laxity measurements performed in the clinic were suggestive or diagnostic of pathologic posterior laxity in 50 patients.
Abstract: Instrumented anterior/posterior laxity measurements were performed on 138 patients evaluated within 2 weeks of injury with their first traumatic knee hemarthrosis. All patients were tested with the MEDmetric Arthrometer model KT-1000 in a knee injury clinic. Seventy-five of the patients had knee arthroscopy. Thirty-three had arthrometer laxity tests under anesthesia. Eighty-seven percent of patients arthroscoped had anterior cruciate ligament (ACL) tears and 41% had meniscus tears. One hundred twenty normal subjects were tested to establish normal anterior laxity values. Three tests were used to evaluate anterior laxity: anterior displacement between a 15 and 20 pound force (compliance index), anterior displacement with a 20 pound force, and anterior displacement with a high manually applied force. Displacement measurements in normal subjects revealed a wide range of normal laxity with a small right knee-left knee difference. For example, the 20 pound anterior displacement range was 3 to 13.5 mm with a right knee-left knee difference (mean +/- SD, 0.8 +/- 0.7 mm). Eighty-eight percent of the normals had a right-left difference of less than 2 mm. In the 53 patients arthroscoped who had complete ACL tears, the anterior laxity measurements performed in the clinic were suggestive or diagnostic of pathologic anterior laxity in 50 patients.
657Â citations