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Biomedical subjects

F Pipino

Publications and source records attributed to F Pipino.

At least 19 recordsLinked to original sources
PubMed2000

The TACK knee prosthesis. Analysis of a uniform case series.

We implanted the total arthroplasty knee or TACK prosthesis in 40 patients with degenerative osteoarthritis. We used the same surgical technique in all patients. Full extension and flexion more than 90 degrees were achieved in all 40 knees. All patients obtained a HSS score of more than 88 points. The results confirm that the TACK prosthesis provides excellent results in patients with degenerative osteoarthritis if there is no significant bone loss, serious ligament laxity or extensive deformation.

Aged↗
PubMed1997

Biomechanical validation of a new nail-plate for the repair of stable proximal femoral fractures.

The mechanical performance and the stress shielding effects of the Howmedica Spherolock MKII implant were evaluated. Three types of stable proximal femoral fractures were created in composite femurs and fixed with the nail-plate. The femurs were loaded to failure, and the yield strength, stiffness, and failure modes were noted. Additional intact composite femurs were fitted proximally with strain gauges, and the strain was examined under load. The femurs then underwent intertrochanteric fracture, plating, and re-testing. Comparative analysis showed that while the Spherolock system is less strong and stiff than other commonly used implants, it provides excellent and uniform load transfer across the fracture site. Varus rotation of the femoral head under load tended to open the fracture gap and localize the resultant load medially. Stress shielding of the calcar was less than 25% of the applied load even in the worst case. This very low stress shielding behavior was attributed mainly to the implant's low stiffness.

Biomechanical Phenomena↗
PubMed1993

Femoral neck preservation in total hip replacement.

Preservation of the femoral neck in hip arthroplasty creates a particular biomechanical situation which is clearly different from what is found even after partial neck removal. The femoral neck consists in fact of a "cylinder of cortical bone" that can be used as the "base" for anchoring the stem to the femur, in contrast to the press-fit procedure or other solutions. The mechanical and biological advantages are as follows: 1) Primary triplanar stem stability, in particular rotational stability. Rotational movements of the stem are blocked by the tough lateral cortical cylinder of the neck. Resistance to varus-valgus stress and collapse is also increased vertically and frontally. 2) Proximal cortical fixation. Primary fixation of the stem is provided by the neck cortex, whereas its mid-distal part is merely held by the metaphyseal cancellous bone and the tip is undersized with respect to the medullary canal. 3) Stress loads distributed along physiological lines of stress. Retention of the neck permits preservation of the trabecular systems, along which the stress is distributed towards the diaphysis and the greater trochanter. 4) Elasticity of the bone-prosthesis system. Most of the stem is contained within the metaphyseal cancellous bone that lies between the prosthesis and the cortical bone, creating a bone-prosthesis module with variable and integrated elasticity. 5) Preservation of the bone-stock. The amount of residual bone following implant of the prosthesis increases, not only because of the presence of the femoral neck, but also as a result of the preservation of most of the metaphyseal cancellous bone. There is therefore greater bone-ingrowth, which is also favoured by the fewer changes in the endosteal blood supply. 6) Prosthesis revision is simpler, since the stem can easily be removed and a second neck resection performed. Our clinical and experimental studies, together with those of Freeman et al., confirm that the femoral neck is present for a long time after implant. Finally, we report a study of 200 prostheses with a follow-up of 1 to 6 years, demonstrating neck reabsorption in only 1% of the cases.

Biomechanical Phenomena↗
PubMed1989

Bacteriological and histological study of 40 loose cemented hip prostheses.

The causes of the loosening of a hip prosthesis may be inflammatory, mechanical, immunitary or due to detritus. A bacteriological and histological study, in cases where further surgery was needed, may clearly contribute to the aetiopathogenesis of failure. Loose hip prostheses removed at operation were studied from a bacteriological and, in particular, histological point of view. There results were then correlated to clinical, radiographic and laboratory data obtained during follow-up. Inflammation proved to be a constant histological finding. The hyalinosis observed in 22 cases revealed significant analogies with histological pictures of silicotic granuloma, for which an immunitary pathogenesis is the current hypothesis. Thus, it is our belief that this correlation is suggestive of an immunitary based approach in cases where hip prostheses fail due to loosening.

Activities of Daily Living↗
PubMed1989

The Cathcart elliptical orthocentric endoprosthesis. A long-term clinical and radiographic study.

In 1971 Cathcart proposed the use of an elliptical head for the femoral endoprosthesis, based on his anatomical studies which had proved that the normal femoral head is elliptical and not spherical. Important biomechanical studies have also shown that the periacetabular trajectory system also assumes an elliptical gothic arch shape during stress loading (Fischer and Olivier, 1979). The authors therefore decided to use an elliptical head because it improves lubrication and therefore nourishment of the acetabular cartilage, and because it better distributes the load. Between 1977 and 1987 121 endoprostheses were implanted, of which 92 were followed up after an average of 5 years. The follow-up showed that good results may be obtained with this type of prosthetic head, and in particular that there was almost no acetabular erosion and only a moderate decrease in the joint space. These results show that the elliptical head is better adapted to the acetabulum during load as compared to the spherical head, and is therefore better at safeguarding the osteoarticular structures with which it articulates. The authors therefore regard it as superior not only to the spherical head, but also to the so-called bipolar double-hinge prostheses.

Aged↗
PubMed1988

Experience with thymopentin in the treatment of periarthritis humeroscapularis, tendinitis, and gonarthrosis by local infiltration.

A total of 122 patients with periarthritis humeroscapularis, tendinitis, and gonarthrosis were accepted into a controlled, randomized double-blind study; of these patients, 61 subjects were administered local infiltrations of thymopentin (Timunox) 1 ml (50 mg) plus lidocaine 1 ml (2%), once a week for a period of 5 weeks. 61 subjects were during the same time treated with methylprednisolone depot 1 ml (40 mg) plus lidocaine 1 ml (2%). Demographic and clinical parameters were comparable in both groups. Intergroup comparison on completion of the therapy with regard to the criteria "pain at rest", "pain on pressure", "disability of articulation", and "pain relief" revealed statistically significant superiority of thymopentin. No unexpected drug experiences were observed in this double-blind study.

Adolescent↗
PubMed1987

Biodynamic total hip prosthesis.

The biodynamic total hip prosthesis which was devised in 1977-78 and implanted in 1979 was derived from a series of experimental studies and a lengthy clinical experience, both dating back to 1968. This prosthesis introduced two new and original concepts into the field of prosthetic hip surgery: 1) the biequatorial design of the cup; 2) the preservation of the femoral neck. This prosthetic system is based on maximum preservation of the bone stock as well as hip function. The biequatorial cup allows for positioning corresponding to that of the normal acetabulum. The femoral component incorporates features (collar, sagittal and frontal angulation, external surface, etc.) which facilitate proximal cortical fixation and cancellous metaphyseal biological anchoring, thus ensuring total adhesion. The average 3.5 years follow-up (maximum 7 years, minimum one year) in 280 cases confirms the effectiveness of this prosthesis and the validity of the basic principles on which it is founded.

Adult↗
PubMed1987

Arthroprosthesis of the hip at 12 to 16 year follow-up. A clinical and radiographic study of 17 cases.

A clinical and radiographic study of prosthetic replacement of the hip with a very long follow-up permitted us to evaluate the various factors influencing the long-term stability of this arthroprosthesis. Seventeen patients who underwent this operation during the 15 year period from 1969 to 1973 were reviewed clinically (using a points system adopted in our Clinic), and radiographically after periods ranging from 12 to 16 years. There was a reassuringly high proportion (72%) of excellent or good results. The metaphyseal cementation of the stem and the support of the collar were two particularly interesting features observed in this study. This accords with modern concepts of the biomechanics of hip arthroprosthesis.

Adult↗
PubMed1983

Effect of temperature changes in acrylic cement on prosthetic implant surgery. An investigation into the relationship between quantity and temperature changes at different levels on loosening of the implant.

Loosening of the prosthetic stem is one of the most frequent problems in arthroprosthetic replacement. Fixation at the bone/cement interface is therefore of crucial importance. This can be affected by several factors, one of which is the heat generated in the acrylic cement, which may exceed the level at which tissue viability is affected. The authors therefore investigated this phenomenon in theoretical models. These were related to the level and duration of temperature changes at four levels - inside the cement and at the interfaces between cement, implant, spongy bone and cortical bone. Graphs showing temperature peaks and duration are constructed in all the varying conditions and their implications discussed. These concern the viability of osteocytes and vascular tissue, and the mechanical strength of the cement. The implications on design and surgical technique are obvious and point to the need to use the thinnest layer of cement compatible with firm fixation.

Acrylates↗
PubMed1980

["Double-blind" clinical study of a non-steroid anti-inflammatory drug: glucametacine].

A double blind clinical study has been carried out with two non-steroid anti-inflammatory drugs, glucametacine and phenylbutazone in 40 patients suffering from inflammatory and degenerative type arthrorheumopathies, selected and randomised into two groups. Examination of results shows the greater effectiveness of glucametacine (78%)over phenylbutazone (60%). Glucametacine was also statistically (p < 0,05) better from the tolerance point of view.

Adult↗
PubMed1980

Reduction, capsuloplasty and pelvic osteotomy in surgical treatment of inveterate congenital hip dislocation.

A new surgical technique is described for the treatment of inveterate congenital dislocation of the hip in patients aged between 6 and 26 years, i.e., when it is too late for simple surgical reduction of the dislocation and far too early for a total hip replacement. The technique consists of reduction of the dislocated head, followed by capsuloplasty for covering the femoral head with a cap, and pelvic osteotomy with medial displacement of the inferior (acetabular) part of the pelvis. In the 16 patients (17 hips) treated thus far, the follow-up shows that good restoration of hip function has been achieved.

Adolescent↗
PubMed1977

Gluteal fibrosis.

The authors report a histological study of gluteal fibrosis, a disease which in the last few years has become a clinical entity in its own right. This condition is of more frequent occurance than the earlier reports seem to indicate. The salient point emerging from this investigationis that teno-fascial changes exist as well as changes in the striated muscle. These teno-fascial changes are clearly more striking and extensive and should be regarded as primary. They consist of fibrotic thickening of the whole teno-fascial component with regressive changes leading to pseudocystic cavities and eventually to substitution by fibroadipose or adipose connective tissue. The muscle changes, however, generally appear to be localised near the tendon and present the features of simple atrophy and patchy necrosis, also eventually leading to zones of fibrous or fibroadipose substitution. These findings, though not offering a complete explantation of the pathogenesis, justify the description of the syndrome as a primary teno-fascial fibrosis with secondary muscle changes.

Buttocks↗