Gait analysis of pre- and post-meniscectomy knee: a prospective study.

Degenerative changes in the knee joint after meniscectomy are well known. Although likely to be due to changed biomechanics, there is no evidence in the literature to identify the underlying biomechanical alterations. The aim of this study was to analyse lower limb gait biomechanics before and after meniscectomy. Ten patients who required partial medial meniscectomy for irreparable meniscal tear took part in motion analysis before surgery, then at 6 and 12 months post-operatively. A control group was also set up consisting of 10 healthy volunteers. Joint kinematics did not show significant alterations between pre-operative and 6 month post-operative evaluations. However flexion increases at the hip, knee and ankle joint were observed in late swing and early stance phase 12 months after surgery. Hip and knee flexion-extension moments were affected with knee moment altered both before and after surgery. Before surgery and at 6 months after, the changes occurred mainly at the point of push off, while at 12 months they occurred during the swing phase. Hip flexion-extension moment had also changed 12 months after surgery. When examining symmetry of gait patterns prior to surgery, there were differences between the flexion-extension moments of the healthy and of the injured knee at first impact and during late stance. After surgery, asymmetries were not more apparent at first impact, but in late stance phase a reduced knee extension moment in the injured limb was still present. Before surgery, the joint kinematics were not greatly altered and changes were mainly due to pain. After partial meniscectomy, the pain disappeared and new joint responses were observed. These could be caused by the altered mechanics and/or through proprioceptive mechanisms.

The position of the head in space: a kinematic analysis in patients with cervical dystonia treated with botulinum toxin.

Many instruments have been employed in recent years in order to quantify the posture and motion of the head in normal and pathological subjects. Evaluations of this type present many difficulties related to the influence of individual and external factors and to the accuracy of the system used. In patients with cervical dystonia (CD) the only rating scales currently used are semi-quantitative and subjective. More precise information on disease severity and response to the treatment is needed. Posture and motion of the head were evaluated by means of ELITE motion analyser (BTS, Milan, Italy) in 6 patients with the left laterocollis form of CD undergoing treatment with botulinum toxin (BTX). The method emerged as very useful for the quantification of the therapeutic response (which was more marked in motion than in posture). We found an inverse relationship between the degree of motion improvement and the restriction of motion before treatment.

A 3D kinematic method for evaluating voluntary movements of the cervical spine in humans.

The purpose of this study was to assess the reliability of a 3D kinematic method of evaluating movements of the cervical spine. Range of motion (ROM) of the cervical spine was evaluated in 8 control subjects during flexion-extension, rotation and lateral bending movements. The test was repeated on two separate occasions. The ROM test-retest difference ranged from 1.42 degrees for right axial rotation to 9.11 degrees for left axial rotation. The test showed good reliability, with an intraclass correlation coefficient which was higher than 0.74 in extension movement and excellent in flexion, axial rotation and lateral bending. In conclusion, the method proposed for the 3D kinematic analysis of neck movement proved to be useful and non-invasive and to show good-excellent reproducibility. Furthermore the method is easily applicable in clinical practice to evaluate neck function in cervical spine disorders.

Gait patterns after anterior cruciate ligament reconstruction.

The aim of this study is to analyse the changes in select gait parameters following anterior cruciate ligament (ACL) reconstruction. The study was performed on 15 subjects who underwent ACL reconstruction by the bone-patellar tendon-bone technique. Gait analysis was performed using the Elite three-dimensional (3D) optoelectronic system (BTS), a Kistler force platform and the Telemg telemetric electromyograph (BTS). Kinematic data were recorded for the principal lower limb joints (hip, knee and ankle). The examined muscles include vastus lateralis, rectus femoris, biceps femoris and semitendinosus. The results obtained from the operated subjects were compared with those of 10 untreated subjects and 5 subjects without ACL damage. In the operated subjects the knee joint angular values regained a normal flexion pattern for the injured limb during the stance phase. The analysis of joint moments shows: (a) sagittal plane: recovery of the knee flexion moment at loading response and during preswing; (b) frontal plane: recovery of the normal patterns for both hip and knee adduction-abduction moments during the entire stance phase. The examination of ground reaction forces reveals the recovery of frontal component features. The EMG traces show the normal biphasic pattern for the operated subjects as compared to the untreated subjects. The results suggest that the gait parameters shift towards normal value patterns.

Normal gait is differentially influenced by the otoliths.

Postural control depends on the integration of vestibular, somatosensory and visual orientation signals. The otolith contribution to postural control is achieved by the integration of otolith inputs and peripheral afferent inputs involved in crossed reflex pathways. This study shows that a functional linkage between otolith signals and activity in lower limb muscles is detectable in normal human gait. The otolith input appears to dominate particularly the neck proprioceptive and gaze motor influences during normal gait. This is demonstrated by an increase of tibialis anterior muscle activity during retroflexion of the head/neck, leading to an increased stability and counteracting possible perturbations. It is also shown by decrease of coordination during the movement caused by larger displacement of the centre of gravity demonstrated in vector diagrams.