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Biomedical subjects

F Schuind

Publications and source records attributed to F Schuind.

At least 19 recordsLinked to original sources
PubMed1999

Prognostic factors in the treatment of carpal scaphoid nonunions.

The aim of this multicenter study of 138 patients with scaphoid nonunions was to assess the prognostic factors of bone healing or failure after curative surgical treatment options: isolated bone grafting (30%), internal fixation (23%), or combined bone grafting and internal fixation (47%). Bone healing occurred in 75% of cases. Persistent nonunion was evident in 20% of cases; it was possible in 6%. The clinical and radiologic results were worse in the group of failures. Stepwise multiple logistic regression analysis was conducted to identify the factors of prognosis toward bone healing or failure. In univariate analysis, professional heavy work, age of the nonunion of over 5 years, associated radial styloidectomy, and duration of postoperative immobilization were associated with a significantly decreased likelihood of healing of the scaphoid nonunion. In multivariate analysis, the only remaining predictor was the delay between the initial trauma and the treatment of the nonunion. Among the cases of internal fixation (with or without bone grafting), the only predictor in multivariate analysis was the importance of bone resorption. The dorsal approach resulted in a more pronounced loss of wrist flexion and extension amplitudes. If the time elapsed between the initial fracture and the treatment of the nonunion exceeds 5 years, the chances of healing of the nonunion are decreased.

Adult↗
PubMed1998

Modifications of arterial blood flow to the hand after carpal tunnel release.

Any surgical procedure is followed by an inflammatory reaction, associated with arteriolar dilatation and increased capillary permeability. The normal evolution is in most cases a progressive decrease of the inflammatory signs. Some patients however, particularly after orthopedic trauma affecting the extremities, develop algodystrophy, initially characterized by arterial vasodilatation and low capillary flow. In an effort to better understand the normal phenomena seen after uncomplicated hand surgery, the authors have evaluated the postoperative arterial blood flow using the Duplex flowmetry ultrasound technique in 13 patients operated for carpal tunnel syndrome, who did not subsequently develop algodystrophy. After measurement of the transverse section of the ulnar and radial arteries, and longitudinal measurement of the mean velocimetry, the arterial blood flow was calculated. The measurements were done 1, 2 and 4 weeks after the operative procedure. The study demonstrated a moderate (15%-30%) but significant increase in the arterial blood flow to the hand, related to arterial dilatation of the vessels and to an increase in blood velocimetry.

Adult↗
PubMed1997

Magnetic resonance imaging for irreducible posterolateral knee dislocation.

Magnetic resonance imaging (MRI) of an irreducible knee dislocation can help physicians evaluate associated bone and ligamentous lesions. However, caution should be taken when interpreting the images because the capsuloligamentous interposition seen in irreducible knee dislocations may be misdiagnosed as a meniscal lesion.

Aged↗
PubMed1997

Can algodystrophy be prevented after hand surgery?

Algodystrophy is characterized initially by an increase in arterial flow, an increase in blood pool, a decrease in microcirculatory velocity, and a loss of thermoregulatory control. These changes, producing the typical symptomatology, associated diffuse hand pain, diminished hand function, edema, and abnormal color and temperature, are believed now to correspond in most cases to an exaggeration of the normal post-traumatic inflammatory responses and are not the consequence of sympathetic damage. Algodystrophy may be prevented in most hand surgery patients by minimizing the normal postoperative inflammation, by increasing venous return (especially by avoiding plaster casts and constrictive dressings), by controlling post-traumatic pain, by promoting early active mobilization, and by reassuring the patient. If there is any sign of algodystrophy, three-phase bone scintigraphy should be obtained and treatment instituted immediately.

Arm↗
PubMed1996

Glomus tumours of the hand. A retrospective study of 51 cases.

The authors report a series of 51 patients with glomus tumours in the hand. The duration of symptoms before treatment averaged 10 years. No one site or finger was more commonly involved. Objective features were limited to a blue discoloration in 29%, a pulp nodule or a nail deformity in 33%. An osseous defect was seen on plain X-ray films in 36%. Diagnosis depended on clinical suspicion in 90%. Careful dissection and complete excision of the tumour almost always offer permanent relief. A direct transungual approach was used in the subungual tumours with only one cosmetic problem. Recurrence of symptoms occurred in only two cases after a pain-free interval of 2 years.

Adult↗
PubMed1996

Does the normal contralateral wrist provide the best reference for X-ray film measurements of the pathologic wrist?

This study compares in normal subjects the variability of wrist x-ray film measurements between the right and left sides with the variability of the distribution of those measurements within the population. Additional purposes were to evaluate possible differences of these measurements according to sex, age, side, and hand dominance. The variability when comparing both sides was found to be statistically less for the carpal height, radiolunate, scapholunate, and capitolunate angles than within the whole group of subjects, and for those measurements, there was a high correlation (r > .88) between the right and left sides. In addition, the carpal height and the carporadial ratios were lower and the capitolunate angle was higher in women than in men. There was also a significant decrease of the scapholunate angle in older individuals. The clinical implication of these findings is that in unilateral wrist diseases, the normal wrist should be used to provide the reference values of the carpal height and of the carpal angles on profile x-ray films. However, for the radial inclination and palmar tilt of the distal radius and for the ulnar variance, the normal side does not provide a better reference than normal values obtained from databases.

Adult↗
PubMed1996

[Treatment principles in hand fractures].

The fractures of the hand are frequent and represent a problem of public health. The displacement of the fracture occurs because of post-traumatic musculo-tendinous imbalance. The fractures of the hand are to be treated according to four principles: anatomical reduction, followed, when possible, by immediate mobilization, if necessary, by immobilization of the injured parts in the "protective" position (metacarpophalangeal flexion, interphalangeal extension and with the first web space under stretch), and prevention of post-traumatic edema. When an osteosynthesis is performed, the mounting should be stable enough to allow early mobilization. The most useful techniques include external minifixation, and internal fixation using one or several screws.

Bone Screws↗
PubMed1996

[Biomechanics of the normal elbow and following total semi-constrained arthroplasty].

The elbow possesses two degrees of freedom: flexion-extension and pronation-supination. The axis of flexion-extension joins the centers of the capitellum and of the trochlea. The axis of pronation-supination passes through the head of the radius, and through the distal ulnar dome. The functional elbow mobilities include 100 degrees of elbow flexion (30 to 130 degrees) and 100 degrees of forearm rotation (50 degrees of pronation and 50 degrees of supination). The elbow is submitted to high articular contact forces. The joint stability depends on the articular surfaces, capsulo-ligamentous restraints and dynamic muscular contractions. As a practical application of this fundamental knowledge, an experimental study of the effects of total elbow arthroplasty on joint stability and muscle moment arms is reported, insisting on the deleterious effects of implant malpositioning.

Biomechanical Phenomena↗
PubMed1995

Force and pressure transmission through the normal wrist. A theoretical two-dimensional study in the posteroanterior plane.

Force transmission through the wrist in the normal population was investigated using the rigid body spring modeling (RBSM) technique (assuming carpal bones are rigid bodies interposed by series of springs simulating articulating cartilage and constraining ligaments). One-hundred and twenty normal wrist posteroanterior X-rays of adults (evenly divided to represent both genders and two age groups) provided the anatomical data. Reaction forces between the carpal bones were modeled using a system of compression linear springs, representing cartilage and subchondral bone, and of tensile linear springs, representing ligaments. The spring constants were determined based on the material properties of wrist cartilage and ligaments. Assumed axial loads were applied along the metacarpals to simulate a grasp strength of 10 N with active stabilization of the wrist in neutral position. The force transmission ratio at the radio-ulno-carpal joint was 55% through the radio-scaphoid and 35% through the radio-lunate joints. The remaining 10% of the load was passing through the triangular fibrocartilage with minor differences between genders. Among the intercarpal joints, a large percentage of the load of the wrist was transmitted to the scaphoid. The peak pressure was highest at the proximal pole of the radio-scaphoid, with a radio-scaphoid versus radio-lunate peak pressure ratio of 1.6. The most important ligaments in terms of load transmission were those opposing ulnar translation of the carpus. The wrist morphology had little influence on the magnitude and pattern of load distribution. There was no effect of age on wrist force distribution.

Adult↗
PubMed1995

Loose-hinge total elbow arthroplasty. An experimental study of the effects of implant alignment on three-dimensional elbow kinematics.

A previous study suggested that the kinematics of a loose-hinge total elbow arthroplasty (TEA) are those of a truly semiconstrained joint. This study addresses the effects of malposition of the implant. The three-dimensional elbow kinematics during simulated active motion were studied in six cadaver specimens using an electromagnetic tracking device. In addition to simulated active elbow flexion, flexion arcs were obtained under an elbow varus or valgus moment, to calculate the structural varus-valgus laxities. The results after four different Coondrad-Morrey TEA positions of implantation were compared with those of the intact elbow. The flexion-extension amplitudes were not significantly decreased after TEA implantation, except with external rotation of the ulnar component, which resulted in a loss of extension. In the intact elbow and after TEA implantation in any position, the mean varus-valgus deviations throughout elbow flexion were in a narrower range than the structural limits imposed by the ligaments (intact elbow) or the TEA hinge design. With internal malrotation of the humeral component over 10 degrees, however, the valgus structural limit was reached and, conversely, the varus limit with external rotation over 10 degrees. The clinical improvement observed with the semiconstrained TEA is derived from the benefits of the less constrained articulation. The proximodistal changes of TEA implantation have no consequence on the kinematic pattern. Rotational malpositioning of either humeral or ulnar component should be avoided, the first because it changes the kinematic pattern toward the structural limits of the implant and, therefore, may lead to excessive stresses at the bone-cement-implant interfaces and to early loosening, and the latter because it causes loss of extension.

Biomechanical Phenomena↗
PubMed1994

[Plexiform fibrohistiocytic tumor of the hand. Late form].

Plexiform fibrohistiocytic tumours are very rare, apparently benign neoplasms of the superficial soft tissue: only two series and one case report have been described in the literature. Macroscopically located within the dermis or superficial subcutis, they seem to predominate in the upper limbs of children and young adults. Moreover their recurrence rate is relatively high. We report the case of a 56 year old male patient presenting such a plexiform fibrohistiocytic tumour of the hand, which was surgically excised after a progressive clinical evolution of approximately 5 years and in which no recurrence has been observed with a follow-up of more than 24 months.

Follow-Up Studies↗
PubMed1993

Small external fixation devices for the hand and wrist.

Small external fixators have been developed for use in the hand and wrist. The main indications are stabilization of open or infected fracture or non-union of the metacarpals and phalanges; length maintenance in segmental bone loss; and distraction-lengthening of the fingers. The device may be used also for articular or periarticular fracture, closed diaphyseal fracture in adults, fracture in children, various arthrodeses, or corrective osteotomies.

Biomechanical Phenomena↗
PubMed1992

Flexor tendon forces: in vivo measurements.

S-shaped force transducers were developed for measurement of the forces along intact tendons. After calibration, the transducers were applied to the flexor pollicis longus and flexor digitorum superficialis and profundus tendons of the index finger in five patients operated on for treatment of carpal tunnel syndrome. The tendon forces generated during passive and active motion of the wrist and fingers were recorded. For pinch function, the amount of the applied load was measured with a special pinch meter. Tendon forces in the range of 0.1 to 0.6 kgf were measured during passive mobilization of the wrist. Tendon forces up to 0.9 kgf were present during passive mobilization of the fingers. Tendon forces up to 3.5 kgf were present during active unresisted finger motion. Tendon forces up to 12.0 kgf were recorded during tip pinch, with a mean applied pinch force of 3.5 kgf. These results have potential application in determining the amount of force that a tendon repair would have to resist during passive as well as active postsurgical mobilizations.

Carpal Tunnel Syndrome↗
PubMed1992

Vascularized bone transfer for tibial pseudarthrosis. Part II: Vascularized bone and muscle transfers. Exclusive free fibular bone graft.

The techniques of vascularized transfer of a bone segment, or of revascularization of a conventional bone autograft by a pedicle or a microsurgical muscular flap represent one of the most significant advances made during the last years for the treatment of large bone defects of the tibia with associated skin injury. The authors present their experience with 16 cases, including 5 microsurgical transfers.

Adult↗