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Biomedical subjects

J J Rodrigo

Publications and source records attributed to J J Rodrigo.

16 recordsLinked to original sources
PubMed1991

Anterior cruciate ligament allograft transplantation in dogs.

The biomechanical and clinical performance of bone-ligament-bone anterior cruciate ligament (ACL) allografts was studied in eight dogs. Allografts were collected from skeletally mature, healthy dogs using aseptic technique, and stored at -70 degrees for three to five weeks before implantation. The allografts were size-matched to the recipient dogs using ACL length and then rigidly fixed in position with interference screws and Kirschner wires. Three dogs regained a normal gait, and their grafts sustained breaking loads that were 25%, 41%, and 59% of controls. Partial or complete graft failure occurred in the other five dogs at some point in the study. Four had intraligamentous rupture and one had an avulsion fracture of the femoral attachment site. Joint-fluid cytology was normal in all eight dogs. Histologic examination showed persistent lymphoplasmacytic infiltrate. Eventually the allograft cores were incorporated in the host bed. Hyperplasia and fibrosis of the synovial membrane were diffuse and persisted as focal accumulations of mononuclear inflammatory cells.

Animals↗
PubMed1991

Tissue banking.

The Scientific Board of the California Medical Association presents the following inventory of items of progress in orthopedics. Each item, in the judgment of a panel of knowledgeable physicians, has recently become reasonably firmly established, both as to scientific fact and important clinical significance. The items are presented in simple epitome, and an authoritative reference, both to the item itself and to the subject as a whole, is generally given for those who may be unfamiliar with a particular item. The purpose is to assist busy practitioners, students, researchers, or scholars to stay abreast of these items of progress in orthopedics that have recently achieved a substantial degree of authoritative acceptance, whether in their own field of special interest or another. The items of progress listed below were selected by the Advisory Panel to the Section on Orthopedics of the California Medical Association, and the summaries were prepared under its direction.

Humans↗
PubMed1990

Interlocking femoral components for revision arthroplasty with allografts.

The use of interlocking screws has been advocated to fix major proximal femoral allografts to femoral prostheses. This study examines the effect of interlocking screws on strength of the component. Model femoral components were tested in axial compression. Drilling one hole diagonally (lateral to medial), drilling one hole anterior to posterior, or drilling one diagonal hole plus one anterior-to-posterior hole did not significantly decrease failure load compared to controls with no holes. However, two diagonal holes or horizontal, medial-to-lateral holes were weaker. Four cases have been done with proximal femoral allografts fixed to porous-coated femoral components with proximal and distal interlocking screws. Initial results in these cases are good.

Adult↗
PubMed1989

Replacement of the anterior cruciate ligament. A comparison of autografts and allografts in dogs.

To compare the efficacy of allograft versus autograft replacement of the anterior cruciate ligament, 15 dogs had the ligament cut and replaced 1 month later: 11 dogs received a frozen bone-ligament-bone allograft cruciate ligament, while 4 dogs received a standard autogenous replacement with iliotibial band. Three of 11 allograft dogs developed postoperative infections and were removed from the study; and two of the remaining eight allograft ligaments were absent at autopsy. All the autograft ligaments were present. From serial clinical and radiographic examinations, there were no differences observed in the two groups. Autopsy studies at 4 months, however, showed an increased inflammatory, pannus-like reaction about the origins and insertions of the six allograft ligaments as compared with the four autografts. The ligament hydroxyproline uptake was lower in the allograft group, averaging 60 percent of the contralateral unoperated on control versus equal to the control in the autograft group. The tensile strength of the allografts reached only 17 percent of the control value versus 41 percent for the autografts. Lymphocytotoxicity testing at 1 month revealed a donor-specific antibody response in 4 of 8 allograft dogs; however, no histologic evidence of immune response was observed in the ligaments. The synovial fluid leukocyte count was elevated in the allograft group at 4 months. The increased synovial leukocyte counts and joint cartilage erosion, the decreased strength and metabolic activity of the grafts, and the evidence of an immune response in the allograft dogs do not support implantation of cadaver cruciate ligaments clinically at this time.

Animals↗
PubMed1989

Inhibition of the immune response to experimental fresh osteoarticular allografts.

The immune response to osteoarticular allografts is capable of destroying the cartilage--a tissue that has antigens on its cells identical to those on the bone and marrow cells. Osteoarticular allografts of the distal femur were performed in rats using various methods to attempt to temporarily inhibit the antibody response. The temporary systemic immunosuppressant regimens investigated were cyclophosphamide, azathioprine and prednisolone, cyclosporine A, and total lymphoid irradiation. The most successful appeared to be cyclosporine A, but significant side effects were observed. To specifically inhibit the immune response in the allograft antigens without systemically inhibiting the entire immune system, passive enhancement and preadministration of donor blood were tried. Neither was as effective as coating the donor bone with biodegradable cements, a method previously found to be successful. Cyclosporine A was investigated in dogs in a preliminary study of medial compartmental knee allografts and was found to be successful in inhibiting the antibody response and in producing a more successful graft; however, some significant side effects were similarly observed.

Animals↗
PubMed1988

An in vitro study of the structural properties of deep-frozen versus freeze-dried, ethylene oxide-sterilized canine anterior cruciate ligament bone-ligament-bone preparations.

The effect of two preparation and storage methods on the structural properties of canine anterior cruciate ligament (ACL) bone-ligament-bone preparations was determined. In Group 1, one knee joint from each dog was tested after storage at -70 degrees for eight to 12 weeks. In Group 2, one knee joint from each dog was sterilized using ethylene oxide, freeze-dried, and then stored at room temperature for four to five weeks prior to mechanical testing. In both groups, the contralateral joint was tested fresh and used as a control. The bone-ligament-bone preparations were loaded in tension until failure and the load at failure, stiffness, and maximum elongation were measured. No preparation method caused a significant decline in breaking strength. In both groups, however, there was a significant increase in elongation at failure noted in the test specimens. This was accompanied, in Group 1 (deep-frozen), by a significant decrease in stiffness in the test joints. A similar trend toward decreased stiffness was observed in the test joints from Group 2 (freeze-dried).

Animals↗
PubMed1987

Deep-freezing versus 4 degrees preservation of avascular osteocartilaginous shell allografts in rats.

Osteocartilaginous allografts (distal femurs of rats) were stored at 4 degrees for six, 12, 24, and 48 hours and at -80 degrees for five days and then evaluated for viability of the bone and cartilage. Storage at 4 degrees for 12 or 24 hours had little effect on cartilage viability but decreased bone viability to 40% and 10% of controls, respectively. Storage at -80 degrees for five days resulted in nonviable bone in all cases but showed an either/or response of cartilage, with high viability in two cases and nonviability in the other eight cases. In a second set of experiments, femurs from rats were stored in situ at 4 degrees for 12 or 24 hours or were harvested and stored at -80 degrees for five days, after which they were transplanted into rats of a different strain. The antibody response to each set of femurs was measured at two, six, and 12 weeks after operation. The 4 degrees storage resulted in a moderately decreased immunogenicity, whereas the storage at -80 degrees resulted in significantly reduced immunogenicity.

Animals↗
PubMed1987

Replacement of the anterior cruciate ligament with a bone-ligament-bone anterior cruciate ligament allograft in dogs.

Acute replacement of the canine anterior cruciate ligament (ACL) with a frozen, bone-ligament-bone anterior cruciate ligament preparation was studied using biochemical, immunologic, and biomechanical testing methods. Nine dogs were used for the study, six dogs received allografts and three received autografts. No tissue antigen matching was performed. All nine dogs were killed nine months after surgery. Necropsy examination revealed that the ACL was not present in three joints (one autograft, two allografts). The two autograft and four allograft ligaments available for mechanical testing sustained mean maximum loads that were 10% and 14%, respectively, of the mean maximum loads sustained by the contralateral ACL. Autoradiography indicated that cellular activity was more pronounced in the autograft specimens. Hydroxyproline uptake was 200% and 45% of normal in the autograft and allograft ligaments, respectively. Both autograft and allograft specimens were producing Type I collagen at the time of killing. Antidonor dog leukocyte antigen (DLA) antibody was detected in the synovial fluid taken at the time of killing from six of six dogs that received allografts and in zero of three dogs that received autografts.

Animals↗
PubMed1985

Pedicle fat grafts for the prevention of scar in low-back surgery. A preliminary report on the first 92 cases.

Encouraged by the results of an experimental study on dogs, the authors performed pedicle fat grafts in 92 patients. The grafts were used in the following groups of patients: following primary disc removal (37 cases); following scar removal in the multiply operated back with definite root findings (37 cases); in patients with spondylolisthesis who had had prior decompressions but developed fifth lumbar nerve root pain after lateral fusion (6 cases); in three patients with spondylolisthesis and simple decompression; in nine patients with spinal stenosis. Pedicle fat grafts were obtained from the subcutaneous layer of fat of the low back in 85 patients and from the buttocks in seven patients. The grafts were brought through openings in the fascia and muscle and were used to cover the dural sac as well as the margins of the nerve root. They were held in position by a fine suture of silk. The results after a minimum follow-up of 1 year and a maximum of 4 years have been excellent or good in 66 percent of the patients who have had lateral fusion with resultant L5 root compression, in 99 percent of patients with spondylolisthesis and decompression only, and in 66 percent of patients with spinal stenosis. The results in the other two groups compare favorably with those reported in the literature.

Adipose Tissue↗
PubMed1979

99mTc-methylene diphosphonate bone imaging in the evaluation of total hip prostheses.

A retrospective study was performed to determine the accuracy of 99mTc-methylene diphosphonate bone imaging in the evaluation of total hip arthrosplasty for lossening and/or infection. Using focally increased activity at the tip of the femoral component or in the region of the acetabular component as a criterion, the examination was 77% specific and 100% sensitive for loosening and/or infection. A possible explanation for the increased uptake at the tip of the femoral component and the role of this examination in the management of a painful total hip prosthesis are discussed.

Bone Diseases↗
PubMed1976

Treatment of Dupuytren's contracture. Long-term results after fasciotomy and fascial excision.

Of 359 hands treated surgically for Dupuytren's contracture, 135 were available for study after two years or more, often because of recurrence. Of the sixty-five hands treated by excision of the involved fascia (subtotal fasciectomy), 63 per cent had recurrences in the area operated on but only 15 per cent had sufficient deformity to warrant another operation. Of the forty-one hands treated by palmar fasciotomy, 43 per cent had recurrent deformities severe enough to warrant further surgical treatment. After palmar fasciotomy, improvement at the metacarpohalangeal joint persisted; but, as expected, the deformity at the proximal interphalangeal joint progressed just as it did in an untreated control group. The average postoperative period of disability was fifty-nine days after fasciectomy and twenty-one days after fasciotomy. Stiffness and hematoma occurred after fasciectomy but were not observed after fasciotomy. A digital nerve was severed during one fasciotomy and one fasciectomy. Excision of the involved fascia, therefore, gave the best long-term results but was associated with a higher incidence of postoperative complications.

Dupuytren Contracture↗
PubMed1975

Arthrography for the assessment of pain after total hip replacement. A comparison of arthrographic findings in patients with and without pain.

Arthrography in twenty-five painful hips of twenty-one patients after total hip replacement and in fifty-three asymptomatic hips of forty-two patients after this procedure showed that arthrographic evidence of loosening was not always associated with pain. More than one-fifth of the asymptomatic hips had arthrographic evidence of loosening. Furthermore, the loosening shown by arthrogram could be confirmed in only seven of twelve hips that were subsequently explored. In addition, there was no apparent relationship between arthrographic loosening and the presence of a Trendelenburg sign. This study casts doubt on the value of an arthrogram in the diagnosis of the cause of pain after total hip replacement.

Hip↗