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J J Comtet

Publications and source records attributed to J J Comtet.

At least 19 recordsLinked to original sources
PubMed2001

[Definition and classification of basal joint osteoarthritis. A critical analysis and proposals. Treatment options].

Several definitions and classifications of basal joint osteoarthritis exist. Each of them can be criticized. The authors propose to define basal thumb osteoarthritis as osteoarthritis of the trapezometacarpal joint associated or not with lesions of scapho-trapezio-trapezoid and/or metacarpophalangeal joints. The proposed classification is derived from the Eaton-Littler classification. Stage O is identical to stage I of the Eaton-Littler classification: trapeziometacarpal instability without cartilage lesions. Stage I is osteoarthritis of the trapeziometacarpal joint only, without metacarpophalangeal deformity. Stage II is trapeziometacarpal osteoarthrites combined with reductible hyperextension deformity of the metacarpophalangeal joint. Stage III is trapeziometacarpal osteoarthrites combined with irreductible metacarpophalangeal deformity. Stage IV is identical to stage IV of the Eaton-Littler classification: combined trapeziometacarpal and scapho-trapezio-trapezoid osteoarthritis. The advantage of the proposed classification is that basal joint osteoarthritis is not only defined as real or potential (stage O) osteoarthritis of the trapeziometacarpal joint, but also includes precise evaluation of two other joints at the base of the thumb. This classification can be a guide for treatment options.

Carpal Bones↗
PubMed2001

[Variability of muscular and articular forces of the thumb. Comparison of three results during lateral grip].

The aim of this paper is to describe three different laboratory studies of muscular and articular forces in the thumb and to compare and discuss their results in term of constraints (forces and moments) at the carpometacarpal joint during key pinch. Imaging techniques such as biplanar roentgenograms or computer tomography imaging were used on cadaver hands and magnetic resonance imaging on living hands in order to determine bone dimensions, muscle and tendon forces, directions, and centres of rotation. Mechanical models of free bodies with three to five links were created. Problems of balancing of static forces were solved using different methods (electromyography, systematic combination of muscular forces or optimization method). The results in terms of muscular forces or constraints at the carpometacarpal joint showed a strong variability (one to three depending on method and hypothesis). However the three studies all showed subluxation of the carpometacarpal joint balanced by joint constraints. Finally, it was demonstrated using magnetic resonance imaging, that results were strongly influenced by the exact point of application of the forces.

Biomechanical Phenomena↗
PubMed2001

[In vivo cinematic study of the trapezometacarpal joint].

The aim of this study was to assess the trapeziometacarpal joint kinematics from in vivo measurements, both quantifying the ranges of motion and suggesting a suitable joint model. A motion analysis system has been used to collect the spatial trajectories of markers, glued respectively on the thumb and on the hand's palm. A rigorous protocol was set up to make sure of the trapezoid bone's fixity relatively to the hand, and then to be able to characterize the movement of the first metacarpus with respect to the trapezium. The ranges of motion have been measured on two distinct movements: circumduction and flexion-extension, and different types of joints: healthy, pathological and prosthetic. The joint axes of rotation (for flexion-extension and ante-retroposition movements) have been determined on healthy subjects. The computation of rotation amplitudes and positions of joint axes was based upon the finite helical axis concept, which degenerates into finite rotation axis when translations can be neglected. Both the measurement protocol and the calculation method have been validated by comparing the computed joint center with that measured on a radiography, in the case of a spherical prosthesis. The ranges of motion obtained on the healthy subject series were consistent with values published by other authors. Comparisons have been realized between these reference joints and different cases: arthrodesis, arthrosis and prosthesis. The determination of rotation axes of a normal joint has lead to a generalized cardan joint, i.e. two non perpendicular converging rotation axes.

Algorithms↗
PubMed2001

[Total trapezometacarpal prostheses: concepts and classification study].

This paper is an attempt to classify the different types of trapezio-metacarpal total prostheses according to their bio-mechanical principle and to compare the bio-mechanics of these prostheses to that of the normal trapeziometacarpal joint. The trapeziometacarpal joint has two approximate centres of rotation (one in the proximal metacarpal, one in the trapezium), two degrees of freedom and two arc of mobility about 70 degrees. The mechanical model of the trapeziometacarpal joint is a universal-joint called "cardan" with three constraint forces (one axial compression force, and two shear forces, radial and posterior) and one constraint moment around the longitudinal axis. The trapeziometacarpal prostheses may be classified in two main categories: the most frequently used are the "ball and socket" prostheses. Several prostheses, including the surface replacement prostheses have the mechanical characteristics of an universal joint (cardan). Ball and socket prostheses have one centre of rotation, 3 degrees of freedom, three constraint forces in three directions and no constraint moment when "cardan" or surface prostheses have two centres of rotation and 2 degrees of freedom; three constraint forces and one constraint moment. Trapeziometacarpal prostheses may also be classified according to their arc of mobility, or according to their mode of primary fixation (cemented, non-cemented), "press-fit", expansion and to their secondary fixation (hydroxyapatite).

Biomechanical Phenomena↗
PubMed2001

[Comparison of primary trapezometacarpal cup fixation using mechanical tests].

INTRODUCTION: In order to optimise the primary fixation of the cup of the Arpe (Biomet Merck) trapeziometacarpal prosthesis, several geometries have been studied. The mechanical strengths of the primary fixations ensured by cup "with slots", "bladed" and "with crown", have been assessed and compared to the one obtained for the primary anchorage of the Arpe cup. METHOD: For each cup, the strength of the primary fixation has been assessed in torsion (torque along the cup axis) and bending (torque perpendicular to the cup axis). Tests have been performed on prototype cups set up in a vertebral body of lamb cancellous bone. Torque recording allowed the assessment of the maximum strength for each cup type. RESULTS: Arpe and cup "with slots" showed an effective bending strength, respectively due to the three anchorage picks and to the equatorial over-thickness. However, the cup "with crown" demonstrated a better bending strength with a mean torque of pulling out Cbending = 0.89 Nm. In torsion, the three anchorage picks of the Arpe cup did not allow a solid anchorage. For such a loading, the cup "with crown" also showed the best torsion strength with a mean unsealing torque Ctorsion = 0.83 Nm. DISCUSSION: The equatorial over-thickness seems to give good bending and torsion strengths to the "bladed" and "with crown" cups, with a press-fit effect. Replacing the fixation points of the Arpe cup by a crown also allowed the improvement of its torsion strength.

Arthroplasty, Replacement↗
PubMed1996

Experimentally induced ulno-carpal instability. A study on 13 cadaver wrists.

This experimental work studies the role of ligamentous structures in suspending the carpal bones from the radius and ulna. Thirteen human cadaver wrists underwent a distal radio-ulnar arthrodesis in a neutral position and an arthrodesis between the three bones of the first carpal row. Progressive postero-anterior forces in a palmar direction were applied to the fused carpal bones. Displacement was measured by two dial gauges before and after sequential section of the different fibrous structures. The largest absolute average displacement (both, dorso-palmar and induced rotational displacement) was observed after section of the ulnar styloid process. No significant differences were observed after section of the extensor retinaculum, extensor carpi ulnaris sheath, posterior ulno-carpal and posterior radio-carpal ligaments. This work suggests that the carpus is suspended not only from the radius, but also from the distal ulna and particularly at the ulnar styloid and the structures which insert onto it.

Arthrodesis↗
PubMed1996

[Cover of the Achilles tendon by peroneus brevis and flexor hallucis longus flaps. Apropos of 5 clinical cases].

Exposure of the Achilles tendon may be secondary to injury, trophic ulceration or surgical management of Achilles tendon rupture. We used peroneus brevis (PB) and flexor hallucis longus (FHL) muscle flaps to cover the Achilles tendon. The muscular portion of these muscles extends very distally, allowing their transposition to the Achilles region. PB and FHL are narrow (about 4 centimeters); the use of both muscles increases their possibilities of coverage. We used PB alone in one case and both muscles in four cases. In every case we obtained a good functional and cosmetic result. Various fascio-cutaneous flaps have been described for the reconstruction of the Achilles region. When there is an infection, muscle flaps are preferable to fascio-cutaneous flaps because they provide well vascularized tissue. We consequently suggest the use of PB and FHL to cover the Achilles tendon when it has been exposed for a long time or when it is infected. It seems especially indicated when skin necrosis occurs after surgical management of Achilles tendon rupture.

Achilles Tendon↗
PubMed1995

Decision making and results in subtotal and total lower leg amputations: reconstruction versus amputation.

As a result of modern therapeutic and technological advances, the surgeon has the ability to salvage even the most severely injured lower limbs. However, the success of replantation nowadays is no longer measured simply on the basis of restoration of viability but also on functional outcome compared with primary amputation with early prosthetic fitting, the risk to the patient during and after replantation and the overall time of treatment which should not exceed 2 years. Although every major limb replantation has to be considered individually, the decision-making process for reconstruction (replantation/revascularisation) versus amputation with subsequent early prosthetic fitting should be determined by objective criteria. Based on personal experience and an extensive literature search, an algorithm for treatment of amputation or amputation-like injuries to the lower leg has been developed and tested in a clinical study. A 100% viability success rate was achieved. There was not only a significant increase in the percentage of "functional extremities" but also a doubling in grade I results. Moreover, there was a 50% reduction in patients presenting a "non-functional extremity", and no patient required a secondary re-amputation. The replantation risk (e.g., risk of severe systemic disturbance during and/or after replantation) was about 16.6% (2/12) in our study. There was a significant decrease in the postoperative complication rate and no patient died during or after replantation. Based on our experience, if reconstruction in subtotal or total lower leg amputation is done for a well-selected patient group, good functional results with a reasonable replantation risk and a reasonable time for social re-integration can be achieved.

Adult↗
PubMed1995

[Ulnar parametacarpal flap. Anatomical study and clinical application].

The ulnar border of the hand provides a new skin flap which is very useful in the reconstruction of defects of the palm of the hand and ulnar fingers. An anatomical study of the dorsal carpal branch of the ulnar artery and its various branches has led us to propose the ulnar parametacarpal flap either as a pedicle or free microsurgical transfer. The territory of the dorsal carpal branch of the ulnar artery allows harvesting of a simple sensitive skin flap or a composite flap comprising a bone or tendon island flap. Description of the distal communicating vessels with the ulnar collateral artery of the little finger extends the territory of the ulnar parametacarpal flap; based on a retrograde blood supply, it can reach the dorsal and palmar surfaces of the ulnar fingers. The authors present several clinical applications and define the place of this new flap among the various treatment options for the hand.

Hand↗
PubMed1994

[Arthroscopy of the wrist].

Wrist arthroscopy may add specific datas to that provided by standard or motion view radiographs, arthrography, bone scan, TDM or RMN. Eight portals allow direct visualization of articular surfaces of radio-carpal and medio-carpal joints, triangular fibrocartilage, spaces between the carpal bones, interosseous and extrinsic ligaments. Wrist arthroscopy may be useful to evaluate lesions involving ligaments or cartilages, in degenerative or post-traumatic conditions. Arthroscopy may help to the decision in treatment of carpal instabilities, scaphoid pseudarthrosis, or Kienbock disease. Operative arthroscopy may allow shaving of damaged cartilage or fibrocartilage, bone resection or triangular fibrocartilage reinsertion.

Arthroscopy↗
PubMed1993

Two-point discrimination tests versus functional sensory recovery in both median and ulnar nerve complete transections.

Transection of both median and ulnar nerves provides an objective model to compare sensory and functional recovery. 22 patients were evaluated after nerve repair. The mean age was 30 years and the mean time since surgery 80 months. Primary direct suture was performed in 15 patients and six grafts were necessary. Median nerve suture and ulnar nerve graft were combined in one case. Both sensory and functional evaluation were completed. Statistical evaluation analyzed the relationship between age, injury location, mechanism, type of rehabilitation and the result, and the relationship between two-point discrimination distance (2-PD) and the functional score. According to the S0 to S4 grading, only 26.5% (ulnar) and 31% (median) of direct suture cases achieved S3+ or more. All nerve grafts in adults were poor. A strong relationship was found between two-point discrimination distance (moving and static) and the functional result, even after multivariate analysis. A modification of the Medical Research Council's classification is suggested.

Adolescent↗
PubMed1993

Perilunate dislocations and fracture-dislocations: a multicenter study.

A series of 166 perilunate dislocations and fracture-dislocations from 7 centers was retrospectively studied. The diagnosis was missed initially in 41 cases (25%). A classification system was presented. The perilunate fracture-dislocations were more frequent than the perilunate dislocations at a ratio of two to one. The displacement was dorsal in 161 cases (97%) and palmar in only 5 (3%). The dorsal transscaphoid perilunate fracture-dislocations represented 96% of the dorsal perilunate fracture-dislocations and 61% of the whole series. The clinical and radiologic outcome of 115 perilunate dislocations and fracture-dislocations with at least 1 year and an average of 6 years 3 months of follow-up was studied. Open injury and delay of treatment had an adverse effect on clinical results, whereas anatomical type had less influence. In cases treated early, the clinical results were satisfactory but the incidence of post-traumatic arthritis was high (56%). In the dorsal perilunate dislocation group of pure ligamentous injuries and in the dorsal transscaphoid group, the best radiologic results were observed after open reduction and internal fixation. In the latter group, the fixation of the scaphoid alone was not always sufficient and left occasionally scapholunate dissociation, lunotriquetral dissociation, ulnar translation of the carpus, or other carpal collapse patterns. The initial appraisal of both the osseous and ligamentous pathology was very important.

Adult↗
PubMed1993

Intraoperative histopathologic nerve examination in brachial plexus injury.

A new method of indirect intraoperative evaluation of axonal quality in a proximal nerve stump by immediate observation of the myelin sheath is presented. Using this method in 18 cases of brachial plexus injuries, the proximal stumps of particular roots or trunks were classified as unfavorable, favorable, or fair. This histologic grading was compared to the clinical result obtained after surgical repair of these nerves in the corresponding territory. In three cases, the proximal stump of the brachial plexus root was sacrificed because of an unfavorable grade, and a nerve transfer was performed: the results were useful in two cases and "academic" in one case. Among 12 cases with favorable histologic grades, nine were associated with useful function and three were "academic". Among three cases with a fair histologic grade, two were associated with an "academic" result and one was useful in a nine-year-old child. Retrospective comparison with classic examination after axon staining showed that intraoperative histopathologic grading was somewhat too optimistic in six cases and was relevant in 12 cases. This method may be helpful in choosing proper methods for brachial plexus repair. A normal or almost normal histopathologic condition in the proximal stump of the nerve is mandatory for obtaining a useful clinical result after repair.

Adolescent↗
PubMed1989

Emergency knee joint salvage utilizing a free musculofasciocutaneous flap based on the anterior tibial artery: case report.

A young adult male presented with a traumatic amputation at the upper third of his left leg and an extensive soft tissue loss around his left knee. A free musculofasciocutaneous flap was elevated on the anterolateral part of the amputated segment and transferred to the soft tissue defect around the proximal left tibia in order to avoid an above-knee amputation. The entire flap depends on the anterior tibial artery for its blood supply. The anatomy of the flap is outlined. The importance of the musculocutaneous blood supply as well as the presence of an extensive fascial component make the flap very reliable. An 18-month follow-up period showed a uniformly well-contoured soft tissue coverage and an optimal functional result.

Adult↗
PubMed1989

Biomechanical basis of transfers for shoulder paralysis.

Elevation of the scapulohumeral joint can be executed by two different and distinct systems, both capable of separately performing this movement. The deltoid muscle is composed of several parts contracting independently, sometimes antagonistically between them and providing elevation in different directions. Parts two and three (Fick) of the deltoid are essential because they are lateral to the centers of rotation and work in the plane of the scapula. The supraspinatus and adjacent muscle system can produce compensatory movements with full elevation in the plane of the scapula. Lateral rotation is absolutely necessary for abduction in the coronal plane. Rotatory muscles inserted on the tuberosities of the proximal part of the humerus are more efficient than those inserted on the humeral diaphysis. Vertical and horizontal stabilization of the humeral head in the glenoid fossa is the result of a complex balance between several muscles and passive factors. Trapezius and serratus anterior are essential for the rotation of the scapula around its centers of rotation.

Biomechanical Phenomena↗