[How to avoid operative injury to Martin-Grüber communicating branch in the transmuscular medial approach of the elbow?]. / Comment éviter les lésions iatrogènes du rameau communicant médio-ulnaire de Martin-Grüber dans la voie d'abord transmusculaire médiale du coude ?

The incidence of Martin-Grüber medio-ulnar communicating branch (MUCB), from median nerve to ulnar nerve, is about 20%. To avoid operative injury to MUCB, the authors suggest some modifications to the medial approach of the elbow. They suggest medial aponeurotomy of the anterior compartment of the forearm, disinsertion of the medial epicondylar muscles with dissection between the flexor carpi ulnaris (FCU) and the other medial epicondylar muscles, not exceeding 3 cm distally. This allows a valuable exposure of the elbow joint through a medial approach, with FCU disinsertion and ulnar nerve transposition preserving the ulnar nerve vascularization, without injury to the MUCB.

A joint coordinate system proposal for the study of the trapeziometacarpal joint kinematics.

The International Society of Biomechanics (ISB) has recommended a standardisation for the motion reporting of almost all human joints. This study proposes an adaptation for the trapeziometacarpal joint. The definition of the segment coordinate system of both trapezium and first metacarpal is based on functional anatomy. The definition of the joint coordinate system (JCS) is guided by the two degrees of freedom of the joint, i.e. flexion-extension about a trapezium axis and abduction-adduction about a first metacarpal axis. The rotations obtained using three methods are compared on the same data: the fixed axes sequence proposed by Cooney et al., the mobile axes sequence proposed by the ISB and our alternative mobile axes sequence. The rotation amplitudes show a difference of 9 degrees in flexion-extension, 2 degrees in abduction-adduction and 13 degrees in internal-external rotation. This study emphasizes the importance of adapting the JCS to the functional anatomy of each particular joint.

[How to define the joint movements unambiguously: proposal of standardization for the trapezometacarpal joint]. / Comment définir sans ambiguïté les mouvements d'une articulation: proposition de standardisation pour l'articulation trapézométacarpienne.

In order to define the movements of a joint, clinicians usually use anatomic terms. These terms are clearly understandable for a simple movement, defined in an anatomic plane. However, these terms are ambiguous for complex movements or for movements out of an anatomic plane. This, for instance, is the case for the internal-external axial rotation of the trapezometacarpal joint. For the study of complex movements, engineers preferentially use methods such as Euler angles, which correspond to three angles about three axes chosen in a defined order or sequence. Thus, the International Society of Biomechanics has proposed a joint coordinate system definition where every axis is associated with a functional degree of freedom of the joint. The first and third axes are embedded in the proximal and distal segments whilst the second axis, called the "floating" axis, is always orthogonal to the other two. The present work deals with the application of this concept to the trapezometacarpal joint. The two principal degrees of freedom, of flexion-extension and of abduction-adduction are defined following classical anatomical axes of respectively the trapezium and first metacarpal. Conversely, internal-external axial rotation is defined about the "floating" axis which does not have anatomical definition but can be geometrically deduced from the two others.

[Flexor digitorum superficialis tendon transfer for intrinsic paralysis in leprosy]. / Transfert tendineux palliatif utilisant le Flexor Superficialis Digitorum dans les paralysies intrinsèques d'origine lépreuse.

A follow up study was performed in the rehabilitation centre for patients with leprosy in Hôchiminhville - Vietnam. All patients had claw-hand deformity due to ulnar and median nerve intrinsic paralysis. Thirty-two affected hands (128 long fingers) were included in the study. A Bunnel-Littler tendon transfer procedure was performed using a four-tailed graft of the flexor digitorum superficialis of the third finger. Clinical evaluation included anatomical measurements of interphalangeal and metacarpal joints in complete extension and in the intrinsic position. In the open hand assessment, 48.5% reported good results, 14.8% medium results and 36.7% poor results. With the hand in the intrinsic position, 53.9% achieved good results, while 33.6% achieved medium results and poor in 12.5%. Poor functional outcome is related to a failure of this procedure and seems to be due to extensor tendon laxity, with or without stiffness of the interphalangeal joints. There were many anatomical deformities (27.3%) found at the time of follow up, notably boutonniere (51.4%) and mallet finger deformities (31.4%) The fourth and fifth fingers had the worst results. We have therefore decided to change our protocol for claw-hand correction and use the Bouvier test in deciding on our surgical indications. Preoperative physiotherapy is absolutely necessary to reduce stiffness of the interphalangeal joints.

Transfert tendineux palliatif utilisant le Flexor Superficialis Digitorium dans les paralysies intrinseques dorigine lepreuse / Flexor digitorum superficialis tendon transfer for intrinsic paralysis in leprosy

A follow up study was performed in the rehabilitation centre for patients with leprosy in Hôchiminhville - Vietnam. All patients had claw-hand deformity due to ulnar and median nerve intrinsic paralysis. Thirty-two affected hands (128 long fingers) were included in the study. A Bunnel-Littler tendon transfer procedure was performed using a four-tailed graft of the flexor digitorum superficialis of the third finger. Clinical evaluation included anatomical measurements of interphalangeal and metacarpal joints in complete extension and in the intrinsic position. In the open hand assessment, 48.5% reported good results, 14.8% medium results and 36.7% poor results. With the hand in the intrinsic position, 53.9% achieved good results, while 33.6% achieved medium results and poor in 12.5%. Poor functional outcome is related to a failure of this procedure and seems to be due to extensor tendon laxity, with or without stiffness of the interphalangeal joints. There were many anatomical deformities (27.3%) found at the time of follow up, notably boutonniere (51.4%) and mallet finger deformities (31.4%) The fourth and fifth fingers had the worst results. We have therefore decided to change our protocol for claw-hand correction and use the Bouvier test in deciding on our surgical indications. Preoperative physiotherapy is absolutely necessary to reduce stiffness of the interphalangeal joints.

[The trapezio-metacarpal joint: the strain of the ligaments as a function of the thumb position. Study on an enlarged model]. / L'articulation trapézométacarpienne: l'allongement des ligaments en fonction de la position du pouce. Etude sur modèle agrandi.

INTRODUCTION: The aim of this paper was to develop an enlarged anatomical model of the trapezio-metacarpal joint in order to measure the strains on the ligaments when this joint was passively moved in several directions under constant loading. MATERIAL AND METHOD: A model of the two first rays of the hand was made in polystyrene, at a X3 enlargement, and the ligaments substituted by rubber bands with well characterized mechanical properties so as to reproduce the actual ratio of stiffness (approximately = 10) of the different tissues (bones and ligaments) found in real life. The first metacarpal was moved in 6 directions as described by Ebskov (1970) and Pieron (1973, 1980) using a small spring exerting a constant force (1.5 N) tilted at 30 degrees with respect to the transverse plane. The strain was measured between two white marks for each model ligament and each direction respectively, and the percentage of lengthening was calculated. A statistical study was performed using the non-parametrical Test of Wilcoxon in order to compare the ligament strains obtained in the different directions of loading. RESULTS: The largest strains were observed in the intermetacarpal ligament and in the anterior oblique ligament reaching 26 to 39% in direction J (posteromedial) and in direction L (posterolateral). Deformations of the two parts of the dorsoradial ligament and of the posterior oblique ligament were equal or inferior to 12% and were observed in the other 4 directions: D, F, K, I (Anterolateral, maximal anteposition, anteromedial, medial) and their combinations. CONCLUSION: . These data may be useful for helping the understanding of the biomechanics of the basal joint of the thumb. Nevertheless, we are dealing here with a simplified model, which must be considered with caution if the results are to be applied to the living joint.

[Variability of muscular and articular forces of the thumb. Comparison of three results during lateral grip]. / Variabilité des forces musculaires et articulaires de la colonne du pouce. Résultats comparés de trois études lors d'un geste de pince latérale.

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.

[In vivo cinematic study of the trapezometacarpal joint]. / Etude cinématique in vivo de l'articulation trapézométacarpienne.

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.

[Total trapezometacarpal prostheses: concepts and classification study]. / Prothèses totales trapézométacarpiennes: concepts et essai de classification.

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).

[Definition and classification of basal joint osteoarthritis. A critical analysis and proposals. Treatment options]. / Définition et classification des rhizarthroses. Etude critique et propositions. Conséquences thérapeutiques.

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.

[Comparison of primary trapezometacarpal cup fixation using mechanical tests]. / Comparaison de l'ancrage primaire de cupules trapézométacarpiennes par tests mécaniques.

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.

[Cover of the Achilles tendon by peroneus brevis and flexor hallucis longus flaps. Apropos of 5 clinical cases]. / Le recouvrement du tendon calcanéen par les lambeaux de muscles court péronier et long fléchisseur de l'hallux. A propos de cinq cas cliniques.

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.

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.

[Ulnar parametacarpal flap. Anatomical study and clinical application]. / Le lambeau paramétacarpien ulnaire. Etude anatomique et application clinique.

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.

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.

[Arthroscopy of the wrist]. / Arthroscopie du poignet.

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.

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.

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.

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.