[Tribologic study of hip prostheses]. / Etude tribologique des prothèses de hanche.

The multitude of total hip replacement systems cannot mask the fact that it is after all a matter of friction between two surfaces. The wear and distorsion resulting from this friction are still to be precisely evaluated for each marketed hip system. These two parameters have indeed to be evaluated when new devices are used. The "in vivo" behavior of a hip system is best approached when studied on a model reproducing the hip movements and the cyclic loads endured by the hip throughout walking. Data obtained using this type of model allow us to approach the behavior of metal-polyethylene interfaces: there is always a grinding period whose duration varies from 300,000 to 2,000,000 cycles. The friction factors during this initial grinding period may be two to three times greater than the final ones. Data obtained upon wear over 5 millions cycles correspond to clinical findings. Concerning the high density polyethylene-metal interface, variations of molecular size or supply of supplementary molecules may increase the friction factors up to three times the initial values. But wear may vary much more.

[Treatment of trapezius paralysis by transfer of the levator scapulae]. / Traitement de la paralysie du trapèze par transplantation de l'angulaire de l'omoplate.

The authors present a technique of palliative treatment of trapezius paralysis after injury to the spinal accessory nerve. The transfer of the levator scapulae associated, or not, with the rhomboid minor allows regression of functional signs and a return to normal function of the shoulder. Five cases are exposed, with results ranging from 3 months to 15 years.

[Onychoheterotopia with polyonychia associated with Pierre Robin syndrome: apropos of a new case. (Trial of classifying nail ectopia)]. / Onychohétérotopie avec polyonychie associée à un syndrome de Pierre Robin: à propos d'une nouvelle observation. (Essai de classification des ectopies unguéales).

The authors report the second case in the English language literature of a rare abnormality of the fingers and nails associated with Pierre Robin syndrome. The patient was born at term to non-consanguineous parents. The only potentially toxic drug taken by the mother during the first months of pregnancy was Sympathyl, a combined preparation of phenobarbitone, methenamine and plant extracts (boldo, crataegus) used as sedative. The child presented at birth with typical Pierre Robin syndrome responsible for respiratory distress, associated with hypotonia, dysplasia of the right hip and cardiac murmur. His development was marked by pronounced psychomotor retardation. At the age of four the patient was referred for congenital malformations of the hands, and notably bilateral and symmetrical abnormalities of the 5th finger consisting of inflammatory-like tapering, soft tissue hypotrophy, sucked appearance of the ungual phalanx, absence of palmar flexion folds and skin ridges and above all, presence of an ectopic supernumerary nail on the volar aspect of the ungual phalanx. This extra nail was not fused with the dorsal nail, although both met at their lateral edges. Other abnormalities were camptodactylia of the 4th fingers, clinodactylia of the 4th and 5th fingers and irreducible extension of the 5th fingers contrasting with hyperlaxity of their metacarpophalangeal joint. The karyotype (46 XY) was normal. Avulsion of the ectopic nails confirmed that they were distinct from the dorsal nails, having their own matrix.(ABSTRACT TRUNCATED AT 250 WORDS)

[Automatic retroversion of the femur neck during fasciculated nailing of pertrochanteric fractures by the Ender method]. / La rétroversion automatique du col fémoral lors de l'enclouage fasciculé selon Ender des fractures per-trochantériennes.

The shape of the standard Ender nail may result in malunion in external rotation in intertrochanteric fractures treated with this device. The nail is curved in one plane, and is usually introduced into the femur without making allowance for the bowing of the diaphysis and the anteversion present in the neck. We have measured radiographically the anteversion of the femoral neck in three groups of patients after operation using Ender nails, and also assessed the anteversion of the unoperated hip for comparison. In Group I normal Ender nails were used. The operated hip showed an average of 12 degrees of retroversion compared with the opposite side. In Group II the nails were bent anteriorly at their upper end, but an average retroversion of 14 degrees was produced compared with the other hip. In Group III the nails were bent to produce anterior bowing as well as proximal anteversion. The group showed retroversion of only 1 degree compared with the normal side. We therefore recommend that Ender nails be bent in this manner in order to reduce rotatory malunion when used for intertrochanteric fractures of the neck of the femur.

[Desynchronization of the circadian rhythm of oral temperature in young human subjects with poor tolerance for night work]. / Désynchronisation du rythme circadien de la température orale chez des hommes jeunes tolérant mal le travail de nuit.

15 night workers (mean age, 28 years; mean seniority 1.5 years) volunteered to measure their oral temperature (clinical thermometers 0.05 degrees C precision) 5 times/24 hrs. during a 21 day span. Time series were analyzed individually according to 3 methods. 11 of the subjects with a good tolerance had (with one exception) their prominent circadian period tau equal to 24 hrs. as well as a relatively large circadian amplitude (A from 0.19 to 0.42 degrees C). By contrast, subjects with a poor tolerance (sleep disorders, persisting fatigue, psychological troubles, etc.) had a tau value ranging from 24.9 to 25.7 hrs. associated with a relatively small rhythm amplitude (A from 0.04 to 0.13 degrees C). These results support the hypothesis that a desynchronisation of circadian rhythms help to explain why certain subjects do not tolerate shiftwork.

Arthroplasty of the rheumatoid wrist by silicone implants. Experience with forty cases.

The authors report their first evaluation of 40 arthroplasties of the wrist with the Swanson implant. The indication for this procedure was principally severe damage to the wrist joint. The radiologic findings have been summarized. In regard to operative technic, there have been no major problems. In 20 cases also arthroplasty of the head of the ulnar was done. There were no significant early complications. The clinical results after 14 months, with a range of 6 to 45 months, was always satisfactory in regard to pain and the preservation useful flexion and extension. So far, tolerance to the implant seems to be satisfactory. The joint narrowing, regularily found in the new articulation, does not detract from the long-term results. Thus the authors retain a favorable impression of this arthroplasty which should find a place in the treatment of badly damaged rheumatoid wrists. In addition to relieving the pain, it preserves mobility that would be sacrificed with an arthrodesis. Among the associated procedures, the authors have been disappointed with arthroplasty of the head of the ulna and have given it up.

Isolated traumatic dorsal dislocation of the distal radio-ulnar joint. Report of seven cases.

The authors report seven cases of isolated dorsal dislocations of the distal radio-ulnar joint. Four were recent dislocations and three were old, chronic dislocations. Acute dislocations were treated surgically. An anatomic study on human cadavers enabled us to define the injuries responsible for radio-ulnar dislocations. An electromyographic study of the extensor carpi ulnaris confirmed its role as a dynamic stabilizer of the ulnar head. Two of the three old dislocations were revised after an attempt at ligamentous reconstruction. These patients benefitted from a resection of the ulnar head. The third patient one underwent a Sauve-Kapandji procedure. Cadaver studies underline the fact that ligamentous reconstruction procedures are actually tenodeses.

Intertrochanteric flexion osteotomy as an only alternative to total hip arthroplasty in advanced osteoarthritis. A ten-year follow-up.

This report is based on the study of 63 intertrochanteric flexion osteotomies of the hip with a ten-year follow-up. Every patient had severe osteoarthritis of the hip where abduction or adduction osteotomies could not possibly have recentered the femoral head in the acetabulum. The only alternative would have been a total hip arthroplasty. The reappearance of a congruent joint space on the anteroposterior roentgenogram of the proximal femoral epiphysis in flexion was the criterion for intertrochanteric flexion osteotomy. At ten-year follow-up, 65% had a good result, 10% fair, and 25% poor. This per cent of poor results is comparable to some statistics of late complications following total hip arthroplasties. After osteotomy, infection seldom occurs. Moreover, intertrochanteric osteotomy does not complicate the results of total hip arthroplasty.

[True orientation of the acetabulum as determined by CAT scan. Preliminary results (author's transl)]. / Etude de l'orientation réelle du cotyle grâce au tomodensitomètre axial ou scanner. Premiers résultats.

Valid clinical correlations with biomechanical data require three-dimensional visualization of a joint, in order to determine the true spatial configuration of the various segments of the part studied. The CAT scan has opened a new pathway in this direction, as it supplies precise mathematical information on the segments explored. An original analytical programme was employed in humans to establish the true spatial orientation of the acetabular cavity. The validity of the method was confirmed by comparing results in 31 subjects with the rare cases where such measurements were made, reported in the published literature. The method could be extended to other body regions.

[Atloaxoid dislocation in chronic inflammatory rheumatism. Results of 16 occipitoaxoid arthrodeses]. / La luxation atloïdo-axoïdienne au cours du rhumatisme inflammatoire chronique. Résultats de 16 arthrodèses occipito-axoïdiennes.

Sixteen cases of spontaneous dislocation of the atlanto-axial joint have been reviewed, fifteen in rheumatoid arthritis and one in ankylosing spondylitis. On four occasions there was some neurological impairment, but in eleven there was only pain and stiffness. The only case of ankylosing spondylitis was operated on after failure of conservative treatment. Three patients died between one and eight months after operation, two of them having had severe neurological impairment before operation. In the thirteen other cases, the average follow up was four years. All had satisfactory fusion after grafting from the skull to axis. Six had only a partial reduction of the displacement and united with some displacement of about 5 mm. The results were satisfactory with absence of pain and regression of neurological signs.

[Intertrochanteric flexion osteotomy for severe osteoarthritis of the hip (author's transl)]. / L'ostéotomie de flexion épiphysaire de hanche dans les coxarthroses évoluées. Analyse évolutive et résultats à 5 ans de recul.

Eighty three cases of intertrochanteric flexion osteotomy of the hip for severe osteoarthritis are reported with a five year follow up. Osteotomy is performed in the sagittal plane with flexion of the proximal fragment. The anatomical, biomechanical and operative criteria for this procedure are discussed. The indications are based on a precise radiographic survey of hip congruity in flexion. The majority of the patients had severe osteoarthritis of the hip. Radiographs in abduction or adduction showed no improvement in congruity indicating that there would have been no benefit from a Pauwels type of frontal osteotomy. Results after five years are presented. Seventy-five per cent are good, 10% fair, and 15% are failures. Forty-five patients have a long term follow up of more than ten years which allows analysis of the evolution of this osteotomy.

[Recurrent posterior dislocation of the elbow following malunion of supracondylar fracture of the humerus. Report of a case (author's transl)]. / Un cas de luxation postérieure récidivante du coude liée à un cal vicieux de la palette humérale.

One case of recurrent posterior dislocation of the elbow after malunion of a supracondylar fracture is reported. The malunion was a posterior angulation of the epiphysis of about 30 degrees. A good result was obtained after osteotomy to correct the malunion.