Search PubMed⌕ Search

Biomedical subjects

J F Fetto

Publications and source records attributed to J F Fetto.

13 recordsLinked to original sources
PubMed2006

Prediction of femoral head collapse in osteonecrosis.

The femoral head deteriorates in osteonecrosis. As a consequence of that, the cortical shell of the femoral head can buckle into the cancellous bone supporting it. In order to examine the buckling scenario we performed numerical analysis of a realistic femoral head model. The analysis included a solution of the hip contact problem, which provided the contact pressure distribution, and subsequent buckling simulation based on the given contact pressure. The contact problem was solved iteratively by approximating the cartilage by a discrete set of unilateral linear springs. The buckling calculations were based on a finite element mesh with brick elements for the cancellous bone and shell elements for the cortical shell. Results of 144 simulations for a variety of geometrical, material, and loading parameters strengthen the buckling scenario. They, particularly, show that the normal cancellous bone serves as a strong supporting foundation for the cortical shell and prevents it from buckling. However, under the development of osteonecrosis the deteriorating cancellous bone is unable to prevent the cortical shell from buckling and the critical pressure decreases with the decreasing Young modulus of the cancellous bone. The local buckling of the cortical shell seems to be the driving force of the progressive fracturing of the femoral head leading to its entire collapse. The buckling analysis provides an additional criterion of the femoral head collapse, the critical contact pressure. The buckling scenario also suggests a new argument in speculating on the femoral head reinforcement. If the entire collapse of the femoral head starts with the buckling of the cortical shell then it is reasonable to place the reinforcement as close to the cortical shell as possible.

Computer Simulation↗
PubMed1997

Chondropathia patellae.

The articular surface of the patella and the contiguous articular surfaces of the femoral condyles are sometimes affected by disintegrational changes of the articular cartilage, which remain localized there for a longer period of time. In consideration of the pronounced functional impairment arising at marked changes of these articular surfaces, resection of the patellar surface, metallic resurfacing of the patella, periosteal resurfacing of the patella, or patellectomy have been described as treatment by various authors. Most of these modalities were followed by shortcomings of the results, as indicated in pertinent follow-up examinations and reports. Thus, a more physiological modality of treatment, organic resurfacing of the patella with synovial tissue, was applied in 7 patients and led to satisfactory results as ascertained by long-term follow-up examinations.

Adult↗
PubMed1996

Contracture of the shoulder joint.

The movements of the shoulder joint may sometimes be markedley limited due to posttraumatic or inflammatory changes in the shoulder joint or in adjacent organs, a condition designated as contracture of the shoulder joint or frozen shoulder. The routine treatment consists of positioning the arm as often as possible in abduction, and of diligent active and passive mobilization exercises. In those patients who started the treatment after a long delay so that the articular as well as the periarticular tissues were very shrunken, manipulation of the shoulder joint was carried out under general anesthesia this led to the return of full motion of the joint in the great majority of these patients. However, in those patients who did not benefit by manipulation, surgical revision of the joint and of periarticular structures was carried out for excision of all scarified tissues. The result was restoration of the mobility of the joint to an adequate although not total range.

Adult↗
PubMed1994

A missing link in the evolution of THR: "discovery" of the lateral femur.

Using cadaveric studies and mathematical models that include consideration of the iliotibial band (ITB) as a "tension band," the authors have demonstrated that compression loading occurs throughout the entire lateral femoral cortex from the apophyseal line of the greater trochanter to the lateral femoral epicondyle at the knee. This model suggests that the magnitude of this load on the medial and lateral cortices is proportional to the medial displacement of these cortices from the ITB. The authors have further demonstrated that the "tension band" model is more consistent with actual bone morphology and function than existing models and is a strong argument for the incorporation of design concepts such as lateral extensions into total hip arthroplasty femoral components. Such extensions would permit use of lateral femoral cortical bone as an additional base of prosthesis support, distributing loads over a greater area of the proximal femur. This model, therefore, would theoretically reduce the areas of stress concentration in diaphyseal bone and stress shielding of the proximal femur, both of which appear to be deficiencies of present femoral stem designs.

Biomechanical Phenomena↗
PubMed1992

The anterior cruciate ligament-deficient knee: a diagnostic and therapeutic algorithm.

The anterior cruciate ligament (ACL) of the knee is a common site of sports-related injury. The natural history of chronic instability, reinjury, and further intra-articular damage is well documented. Appropriate management of ACL insufficiency must be based upon a knowledge of the available diagnostic and therapeutic options, their indications, and their effectiveness. At the same time, the treatment plan must be tailored to the demands and expectations of the individual patient.

Algorithms↗
PubMed1990

Functional outcome of hip fusion in the young patient. Follow-up study of 10 patients.

In the young patient, an osteoarthritic or osteonecrotic hip presents a challenging therapeutic problem. Until the long-term results of noncemented total hip arthroplasty are known, hip fusion provides an option to cemented total hip arthroplasty in the young patient with hip disease. The authors describe the outcome of hip fusion in 10 patients with an average follow-up period of 8.5 years. Seventy percent of the patients had a good or very good result with pain relief, and 90% or more had a good or excellent functional result with support aids, ambulation, and climbing stairs. All 10 patients were subjectively satisfied with their hip fusion. A lower incidence of pain in the contralateral hip, ipsilateral knee, and lower back was noted at 8.5 years than that reported at long-term follow-up evaluation and was associated with a satisfactory anatomic position of hip arthrodesis.

Adult↗
PubMed1984

Heterotopic ossification. Incidence and relation to trochanteric osteotomy in 100 total hip arthroplasties.

Heterotopic ossification can impair the functional results of total hip arthroplasty. The causative role of trochanteric osteotomy in heterotopic ossification is uncertain. Postoperative radiographs of 100 total hip arthroplasties were analyzed for incidence of heterotopic ossification. Forty procedures were performed with trochanteric osteotomy and 60 without. There was a 17% overall incidence of clinically significant heterotopic ossification, 22% with osteotomy and 13% without. High- and low-risk categories revealed clinically significant heterotopic ossification in 25% of the high-risk group and in 8% of the low-risk group. In the high-risk group there was a 32% incidence with trochanteric osteotomy and 22% without osteotomy. In the low-risk group there was a 16% incidence without trochanteric osteotomy and a 3% incidence with trochanteric osteotomy. The increase in clinically significant heterotopic ossification in the high-risk group over that of the low-risk group was statistically significant. The present study showed that trochanteric osteotomy tended to increase the incidence and severity of clinically significant heterotopic ossification. These data suggest that trochanteric osteotomy should be avoided, if possible, during total hip arthroplasty to decrease the risk of heterotopic ossification.

Femur↗
PubMed1979

Injury to the anterior cruciate ligament producing the pivot-shift sign.

The clinical entity termed the pivot shift was studied in cadaver specimens and its significance was evaluated. It was found to be highly correlated with a tear of the anterior cruciate ligament, and it corresponded to a sudden anterior-internal rotation subluxation-dislocation of the tibia and posterior horn of the lateral meniscus beneath the lateral femoral condyle.

Adolescent↗
PubMed1978

Medial collateral ligament injuries of the knee: a rationale for treatment.

Isolated MCL I and MCL II lesions evidence good recovery of integrity and function under non-operative modes of treatment. Isolated MCL III lesions may also be treated by non-operative management, but with the expectation of a slightly less successful result. However, there is an 80% incidence of concomitant ligament injury with this grade of lesion. The prognosis following injury to the MCL is significantly influenced by the presence of concurrent compromise of other ligaments, particularly that of the anterior cruciate ligament. Resolution of knee instability and dysfunction following a mixed MCL injury of any grade severity is best accomplished through operative intervention. Therefore, it is the authors' opinion that isolated MCL III and all mixed MCL lesions are best managed with operative treatment. Because of the apparent influence compromise of other ligament structures have on the recovery of MCL function, an attempt must be made to repair all acutely injured structures at the time of surgery. The keystones of a satisfactory result are early and accurate diagnosis, prompt treatment, and when indicated, complete surgical repair.

Adolescent↗
PubMedDate not supplied

The natural history and diagnosis of anterior cruciate ligament insufficiency.

In 233 knees with anterior cruciate ligament insufficiency the characteristic diagnostic signs and symptoms were: a specific mechanism of injury; an audible "pop" at the time of injury; a positive anterior drawer sign' "giving away"; functional disability; periarticular degenerative changes. Unresolved anterior cruciate ligament insufficiency follows a predictable natural history typified by a course of progressive knee dysfunction and deterioration. The progress of deterioration can be significantly modified or arrested by repair or reconstruction of the injured ligament.

Adolescent↗
PubMedDate not supplied

Knee ligament injuries: a standardized evaluation method.

An analysis of the data with total scores in non-acute terms obtained from 280 patients suggests that knee injuries can be evaluated as: Good-Excellent=generally normal or near normal function, with few or no signs and minimal symptomatology, 41-50 points; Fair (+)=slight functional disability, with few signs and mild symptomatology, 36-40 points; Fair (-)=moderate functional disability, with significant clinical signs and moderate symptomatology, 31-35 points; Poor=severely disabled, with marked signs and symptoms of a compromised knee, less than 30 points. These gross categorizations correlate well with the patient's own evaluations of his condition and the physicians' clinical assessment of the status of a given knee. Although the majority of patients have been followed for four years or less with this method, it is felt that the method presented has provided: A consistency and organization of the workup, diagnosis, treatment, and study of knee ligament injuries, not previously available at our institution; an objective measure of individual patient response to treatment and eventual recovery; in general, more objective means of assessing modalities of therapy and modes of primary repair and reconstruction of ligaments; a tool facilitating communication both among physicians and between physicians and patient; a means by which the long term follow-up of an individual patient by more than one physician can become a more efficient undertaking; an increasing data bank of standardized observations from which many ideas are yet to evolve; and most importantly, an improvement and the means possible for further improvement in the care rendered patients with knee ligament injuries; also, the present computerized format has given rise to additional benefits not directly related to the immediate problem of knee ligament injury. One such benefit is the ability to request and receive rapidly, a concise, yet complete legal summary of a patient's hospital course.

Athletic Injuries↗