In vivo kinematics of the first carpometacarpal joint after trapezectomy.

UNLABELLED: First carpometacarpal osteoarthitis is frequent and surgery may be necessary if medical treatment is not efficient. Trapeziometacarpal arthroplasty, trapeziometacarpal arthrodesis and trapezectomy may be proposed. These surgical solutions may modify the carpometacarpal kinematics of the thumb. However, no clinical tools are currently available to assess these modifications. The goal of our study is to assess the TM kinematics, with an optoelectronic system, in patients after trapezectomy. Ten women, average age 53 (range 45 to 67) underwent trapezectomy with ligamentoplasty for trapeziometacarpal osteoarthritis. An optoelectronic device (Polaris(®)) was used to analyse postoperative range-of-motion of the thumb. Splints were used in order to isolate the trapeziometacarpal joint and retroreflective markers were placed both on the splints and on the thumb. Mean flexion-extension, abduction-adduction, axial rotation and circumduction were calculated. RESULTS: The mean range-of-motion of trapeziometacarpal joint was 50 degrees for flexion-extension, 47 degrees for abduction-adduction and 11 degrees for axial rotation. The mean angle between rotation axes was 90 degrees and the mean distance d between the axes was 3 millimeters. Comparisons between patients and healthy subjects showed no significant differences in flexion-extension, abduction-adduction and axial rotation. Circumduction in patients was reduced compared to healthy subjects. No significant differences were noted between the operated side and the contralateral side. DISCUSSION AND CONCLUSION: Our study showed that this protocol can be used in the postoperative follow-up of patients after trapezectomy. We did not find any significant differences compared to the contralateral side. However, circumduction after trapezectomy was reduced compared to healthy subjects.

Normal range-of-motion of trapeziometacarpal joint.

PURPOSE: The range-of-motion of the trapeziometacarpal joint is difficult to assess clinically. The purpose of our study was to constitute a range-of-motion database from normal active trapeziometacarpal joints. MATERIAL AND METHODS: Two hundred hands from 101 healthy subjects (50 female and 51 male) with a mean age of 23.1 years (range: 22 to 35 years) have been evaluated. An optoelectronic device (Polaris) was used to analyse the thumbs range-of-motion. Splints were fitted so as to isolate the trapeziometacarpal joint and retroreflective markers were placed both on the splints and on the thumb. After active flexion-extension, abduction-adduction, axial rotation and circumduction, the different range-of-motion parameters were calculated. RESULTS: The mean range-of-motion of the trapeziometacarpal joint was 41 degrees for flexion-extension, 51 degrees for abduction-adduction and 21 degrees for axial rotation. Comparisons between female and male subjects showed significant differences concerning flexion-extension, abduction-adduction axial rotation and circumduction. No significant differences were noted between right and left hands except for the abduction-adduction movement. DISCUSSION AND CONCLUSION: One hundred and one healthy subjects were analysed for the development of a database of normal active range-of-motion parameters of the trapeziometacarpal joint, with an in vivo protocol. This database should allow comparing the range-of-motion of patients with osteoarthritic trapeziometacarpal joint and assessing surgical outcome.

Functional gait analysis of trans-femoral amputees using two different single-axis prosthetic knees with hydraulic swing-phase control: Kinematic and kinetic comparison of two prosthetic knees.

This paper reports a comparison of the gait patterns of trans-femoral amputees using a single-axis prosthetic knee that coordinates ankle and knee flexions (Proteor's Hydracadence system) with the gait patterns of patients using other knee joints without a knee-ankle link and the gait patterns of individuals with normal gait. The two patient groups were composed of 11 male trans-femoral amputees: six patients had the Hydracadence joint (Group 1) and five patients had other prosthetic knees (Group 2). The reference group was made up of 23 normal volunteers (Group 3). In this work, trunk, hip, knee, and ankle 3-D motion was assessed using the VICON system. Kinetic data were collected by two AMTI force plates, and the knee moment was calculated via the 3-D equilibrium equations. An original questionnaire was used to assess the participants' activity level and clinical background. The results reveal that, during stance, all knee types guaranteed security. After heel strike, the plantar flexion of the ankle enabled by the Hydracadence prosthesis seems to increase stability. During swing phase, hip and knee sagittal motion was nearly the same in both Group 1 and Group 2. By contrast, hallux and sole vertical positions were significantly higher in Group 1 than in Group 2; thus, it seems the link between the ankle joint and the knee joint makes foot clearance easier. No alteration of the lateral bending of the trunk was observed. The protocol proposed in this paper allows a functional comparison between prosthetic components by combining clinical data with objective 3-D kinematic and kinetic information. It might help to determine which prosthetic knees are best for a specific patient.

Finite element model of the human neck during omni-directional impacts. Part II: relation between cervical curvature and risk of injury.

A detailed 3D FE model of the human neck was used to assess a possible relationship between risk of injury and cervical spine curvature for various impacts. A FE model was previously developed, representing the head and neck of a 50th percentile human with a normal lordotic curvature. The model behaviour was omni-directionally validated for various impacts using published results. For the present study, the model was deformed in order to obtain a straight and a kyphotic curvature, and for each geometry, rear-end, frontal, lateral and oblique impact were simulated. Although results showed similar kinematic patterns, significant differences were found in the distribution and peak values of ligament elongations, forces and moments along the cervical spine for the three configurations. It was concluded that the variability observed on the curvature of the human cervical spine may have a significant influence both on the behaviour and on the risk of injury of the neck during impact.

A functional evaluation of prosthetic foot kinematics during lower-limb amputee gait.

This paper reports on a functional evaluation of prosthetic feet based on gait analysis. The aim is to analyse prosthetic feet behaviour under loads applied during gait in order to quantify user benefits for each foot. Ten traumatic amputees (six trans-tibial and four trans-femoral) were tested using their own prosthetic foot. An original protocol is presented to calculate the forefoot kinematics together with the overall body kinematics and ground reaction forces during gait. In this work, sagittal motion of the prosthetic ankle and the forefoot, time-distance parameters and ground reaction forces were examined. It is shown that an analysis of not only trans-tibial but also trans-femoral amputees provides an insight in the performance of prosthetic feet. Symmetry and prosthetic propulsive force were proved to be mainly dependant on amputation level. In contrast, the flexion of the prosthetic forefoot and several time-distance parameters are highly influenced by foot design. Correlations show influential of foot and ankle kinematics on other parameters. These results suggest that prosthetic foot efficiency depends simultaneously on foot design and gait style. The evaluation, proposed in this article, associated to clinical examination should help to achieve the best prosthetic foot match to a patient.