2004 anterior cruciate ligament assisi


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2004 anterior cruciate ligament assisi

  1. 1. NEMOCOsrl CST srl Neuromotor Controlling Operators Cro System Trading
  2. 2. Effect of vibrating proprioceptive activation on the posture of patients after ACL-reconstruction Brunetti O*, Liti A.***, Roscini M.*, Cerulli G.***, Pettorossi V. E*. Filippi G.M.**, Fisiologia Umana, Perugia* Università Cattolica, Roma** Ortopedia, Perugia*** Vibration of muscles elicits short lasting effects, persisting after vibration ending, on muscle tension and posture reflexes. Beyond the increase of muscle tone (TVR), muscle vibration has positive and persisting effects on motor system in many different cases and experimental conditions. In fact, following muscle vibration the performance of the muscles is enhanced in healthy muscles (Bosco, C., M. Cardinale, and O. Tsarpela. Influence of vibration on mechanical power and electromyogram activity in human arm flexor muscles. Eur. J. Appl. Physiol. Occup. Physiol. 79: 306-311, 1999), in palsy neck muscles (Cannon, S. E., J. P. Rues, M. E. Melnick, and D. Guess. Head-erect behavior among three preschool-aged children with cerebral palsy. Phys. Ther. 67:1198-204, 1987), in spasmodic torticollis (Karnath, H. O., J. Konczak, and J. Dichgans. Effect of prolonged neck muscle vibration on lateral head tilt in severe spasmodic torticollis J. Neurol. Neurosurg. Psychiatry. 69:658-660, 2000). On the other hand, proprioceptive training is reported to be able to induce persisting improvements of motor control and body stability. In addition, self motion perception and stepping in place are influenced by neck muscle vibration for many days, suggesting a long term effect of proprioceptors on the internal NEMOCOsrl CST srl Neuromotor Controlling Operators Cro System Trading
  3. 3. spatial representation. On this base, one can easily predict that movements and body stability impaired by joints and muscles pathology may be also improved by prolonged vibratory stimulations. However, the challenge for the researchers in this field is to find how to prolong the positive effects of vibration and induce steady advantage. Recently, we found that a brief sequence of low amplitude, high frequency vibratory stimulation on isometric contracted muscle (>20 micron, 75-120 Hz, 1-2 N, sul ginocchio, 0.2 N sul collo), applied for few consecutive days, 30 minutes each day, is able to prolong the motor benefit of vibration for long period in healthy people. In theory, this particular modality of muscle vibration could be also useful in different pathologic condition concerning the locomotor system and could help patients in recovering correct movements and posture. On this basis, we applied short lasting period of vibration to the quadriceps muscle of subjects underwent anterior cruciate ligament (ACL) reconstruction and we examined their muscle power and equilibrium. Methods. Twenty subjects underwent ACL reconstruction have been studied in double blinded procedure. Informed consent and local ethics committee approval were obtained for all subjects. The subjects were separated in a NEMOCOsrl CST srl Neuromotor Controlling Operators Cro System Trading
  4. 4. stimulated group, receiving vibratory application and a control group that underwent a slight rehabilitation period instead of mechanical vibration Stimulus paradigm. The experimental paradigm consisted of applications of vibratory stimulation (100 Hz, >20 micron peak-to-peak amplitude, 1-2 N force magnitude, by NEMOCO srl Italy, International Patent Instrument) on the skin overlying the distal part of quadriceps, on the operated side, close to the tendon insertion of Intermedius Femoris, Rectus Femoris and Vastus Medialis. Three applications of mechanical vibration (duration of each application 10 minutes, time interval between two consecutive application about 30 sec) were performed every day, in three consecutive days, while Quadriceps was kept in isometric contraction. The vibratory stimulation was applied one month after the surgery and the recording sections were done before and 10, 90 and 270 days after the application. All subjects underwent conventional rehabilitation programs. Recording paradigm: Equilibrium was investigated using a balance platform open (OE) and closed eyes (CE). The duration of each recording period was 51 sec. The parameters estimated were: length of trace, (LT) in mm, mean speed of shifts (SM) in mm/sec., ellipse area (AE) in mm2. The measure was performed with subjects standing up on the operated and non operated leg alternatively, after a brief period of training. The leg force was measured during maximal isokinetic voluntary contraction by using a conventional dynamometer. NEMOCOsrl CST srl Neuromotor Controlling Operators Cro System Trading
  5. 5. Data analysis. The evaluation of the effect on the length of trace (LT), mean speed of shifts (SM) and ellipse area (EA) was performed by comparing the pre-stimulation values and the operated and not operated sides. Analyses of variance (ANOVA) and Tukey’s post-hoc test were used to calculate statistical significance. Results. Repeated applications of unilateral and protracted mechanical perturbations on quadriceps of the knee caused a clear improvement of subject’s equilibrium as shown by the EA, SM, LT values by comparing normalised value of subjects underwent vibration and control. This effect was significantly different at 10 and 90 days after the vibratory application. Later on, after 270 days, the difference became less significant. Conversely, the analysis of Quadriceps force did not showed a significantly difference between treated and untreated subjects along the recovery period. In spite of the significant improvement in the recovery of body balance of treated subjects, there was a difference in the recovery of balance values depending upon the leg the subjects were using for standing up. The difference between the two side was significantly different in treated group, showing a large improvement on the operated side compared to the unoperated side. The asymmetry in the balance recovery suggests that treated subjects perceived a major confidence in using the operated leg for body balance, so that they learn easily the balance strategy when they stand up on the operated leg rather than on the other side. NEMOCOsrl CST srl Neuromotor Controlling Operators Cro System Trading
  6. 6. Discussion The research shows the possibility of facilitate the normal improving in the body balance after ACL reconstruction simply by applying short period of muscle vibration on selected muscles. The long lasting persistence of the effects and the non invasive technique are important factors that may lead to routinely use this vibratory pattern in ACL reconstructed patients. A trophic origin of the results is unlike since 10 days is a too short time (Ahtiainen, J. P., A. Pakarinen, M. Alen, W. J. Kraemer, and K. Hakkinen. Muscle hypertrophy, hormonal adaptations and strength development during strength training in strength-trained and untrained men. Eur. J. Appl. Physiol. 89: 555-563, 2003) Moreover life style of control and treated subjects was the same, thus an improvement of muscle performance cannot be attributed to a muscle exercise after treatment. In any case, the monolateral presence of effects, ipsilateral to the treatment, does not sustain the possibility of a muscle function enhancement due to physical activity. Finally the absence of any effect on the control group and the monolateral improvement of muscle performance suggests a learning in the proprioceptive system Even though mechanical perturbations like vibration can alter muscle stiffness by a mechanism localized inside the muscle and involving cross-bridges, the origin of the reported results cannot be ascribed to such alterations. Actually muscle stiffness changes induced in sarcomeres by mechanical perturbations are characterized by a very short duration NEMOCOsrl CST srl Neuromotor Controlling Operators Cro System Trading
  7. 7. limited to the time duration of the same perturbation. In an attempt to explain the remarkable efficacy of the pattern of vibratory stimulation we used, we considered two factors: the characteristics of the vibration (small amplitude and high frequency) and the combination of contracting effort with the peripheral sensory activation. The efficacy of high frequency stimulation could be explained by taking into account that 100 Hz stimulation has been reported to facilitate long term potentiation and learning at the level of the central structures involved in controlling balance (vestibular nuclei) (Grassi S., Pettorossi V.E. and Zampolini M., Low frequency stimulation cancels the high frequency-induced long lasting effects in the rat medial vestibular nuclei. J. Neurosc., 16:(10): 3373-3380, 1996, Rosenkranz, K., J. C. Rothwell. Differential effect of muscle vibration on intracortical inhibitory circuits in humans. J. Physiol. 551.2:649-660, 2003; M. Steyvers, O. Levin, M., Van Baelen, and S. P. Swinnen Corticospinal excitability changes following prolonged muscle vibration. Neuroreport., 14:1901-1905, 2003) while low frequency could cancel it. The explanation of the efficacy of small amplitude is less obvious. Proprioceptive network controlling a joint complex (muscle, tendon and articular structures) is well known to be powerful activated by mechanical stimulus . Moreover, it has been reported that high threshold cutaneous and non proprioceptive muscle afferents have an important role in controlling the interneuronal activity at level of the spinal NEMOCOsrl CST srl Neuromotor Controlling Operators Cro System Trading
  8. 8. cord, modifying presynaptic inhibition and recurrent inhibition. Particular combination of afferent inputs may lead to remarkable difference in the network facilitation. Finally, the combination of voluntary contraction and peripheral activation may be efficacious because of possibility that conditioning process could takes place in the central nervous system.In fact, the experimental procedure adopted in the present research could be considered a form of associative conditioning induced by two temporally associated stimuli impinging on the same neural network (Kandel, E. R.. In: Principles of neurosciences. Kandel E.R., J.H. Schwartz, and T.M. Jessell (Eds.) Elsevier NY. 1991, pp. 1009-1031). A powerful signal, generated by the trains of mechanical perturbations is conveyed to the neural network controlling the muscle and the joint involved. Since the subject have to keep the quadriceps muscle in isometric contraction, it implies that the same network, controlling the muscle and the knee, is reached by two stimuli temporally associated: i) the afferent signal elicited by the applied mechanical perturbations and ii) the voluntary command determined by the subject to maintain the requested contraction. Such a situation might be considered a paradigm of associative conditioning, and may explain the long term effect of the vibratory stimulation. NEMOCOsrl CST srl Neuromotor Controlling Operators Cro System Trading
  9. 9. Efficacy of conditioning paradigms on proprioception was clearly evidenced in animals (Wolpaw, J. R.. Acquisition and maintenance of the simplest motor skill: investigation of CNS mechanisms. Med. Sci. Sports Exerc. 26:1475-1479, 1994; Wolpaw, J. R., A. M. Tennissen. Activity-dependent spinal cord plasticity in health and disease. Annu. Rev. Neurosci. 24:807- 43, 2001 REVIEWS) NEMOCOsrl CST srl Neuromotor Controlling Operators Cro System Trading