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Biomedical subjects

J R Roberson

Publications and source records attributed to J R Roberson.

At least 37 records · Page 2Linked to original sources
PubMed1992

Proximal femoral bone loss after total hip arthroplasty.

The cause of bone loss from the proximal femur after total hip arthroplasty is multifactorial and may progress to a degree at which loss of support for the femoral component occurs. The most durable means of reconstructing the deficient proximal femur involves bone grafting techniques designed to restore mechanical integrity. Because there is seldom an adequate quantity of autogenous bone available, allograft bone is frequently used. The indications and limitations of this procedure are described as are other treatment options.

Adult↗
PubMed1992

Deep venous thrombosis in total hip arthroplasty.

Deep venous thrombosis (DVT) is the most common complication of total hip arthroplasty. This article discusses the pathogenesis and diagnosis of DVT and recommends prophylaxis and treatment options.

Hip Prosthesis↗
PubMed1990

Prenatal identification of a girl with a t(X;4)(p21;q35) translocation: molecular characterisation, paternal origin, and association with muscular dystrophy.

There are 23 females known with Duchenne or Becker muscular dystrophy (DMD or BMD) who have X;autosome translocations that disrupt the X chromosome within band p21. A female with a t(X;4)(p21;q35) translocation was identified prenatally at routine amniocentesis. At birth, she was found to have a raised CK level, consistent with a diagnosis of Duchenne muscular dystrophy. Her cells were fused with mouse RAG cells and the translocated chromosomes were separated from one another and from the normal X chromosome by segregation in the resulting somatic cell hybrids. Southern blot analysis of the hybrids indicated that the translocation occurred on the X chromosome between genomic probes GMGX11 and J-66, both of which lie within the DMD gene. Further localisation with a subfragment of the DMD cDNA clone placed the translocation breakpoint in an intron towards the middle of the gene, confirming that the de novo translocation disrupted the DMD gene. RFLP analysis of the patient, her parents, and the hybrid cell lines showed that the translocation originated in the paternal genome. This brings to six out of six the number of DMD gene translocations of paternal origin, a fact that may be an important clue in future studies of the mechanism by which X;autosome translocations arise.

Adult↗
PubMed1990

Breast cancer metastatic to the foot with massive bone loss.

An unusual case of rapid destruction of the entire bone structure of the foot in a 53-year-old woman is described. Although metastasis of breast cancer to the foot has been reported, it is uncommon. The unusual aggressive presentation of the metastasis in this case necessitated amputation for the control of pain.

Bone Neoplasms↗
PubMed1990

Bipolar components for severe periacetabular bone loss around the failed total hip arthroplasty.

Twenty-seven patients had revision of a failed total hip arthroplasty using a bipolar component to replace the acetabulum. The procedure was done when periacetabular bone loss precluded stable fixation of the revision component to bone. In addition, three of the operations were done for recurrent dislocation in patients with severe medical problems. Significant component migration occurred in one case, and one patient required reoperation for dislocation in the early postoperative period. Functional results in these 27 patients were quite satisfactory; bone grafts reliably became consolidated to the host pelvis.

Acetabulum↗
PubMed1989

Accessory nerve palsy following thoracotomy.

A previously unreported cause of 11th cranial nerve palsy is described in a 53-year-old man. Dysfunction of the trapezius branch of the spinal accessory nerve occurred following median sternotomy and was documented by electromyography. This injury resulted in dysfunction of the trapezius muscle with loss of support of the shoulder girdle and pain. The injury may have been due to stretching from sternal retraction or injury secondary to internal jugular venous cannulation.

Accessory Nerve Injuries↗
PubMed1988

Late hemarthrosis from a threaded acetabular component.

Painful hemarthrosis 6 months after total hip arthroplasty resulted from erosion of the anterior hip capsule over exposed threads of a threaded acetabular component. The capsular laceration occurred in an area of bone deficiency at the anterior acetabular lip underlying the psoas tendon. The diagnosis was made at the time of surgical exploration. Threaded sockets should be contained by bone in the area of these structures to prevent this previously undescribed complication.

Acetabulum↗
PubMed1988

Porous polymers for biological fixation.

Porous polymers are recommended as coatings for femoral stems on the basis of their low modulus, which allows uniform distribution of stress to surrounding bone and the fabrication of more flexible stems by reducing the metallic cross section. Application of the porous polymer coating to the metallic substrate reduces metal ion release; the polymer coating does not affect the mechanical properties of the device. Porous polytetrafluoroethylene-carbon fiber composite, (PCFC), porous polyethylene, and porous polysulfone are undergoing investigation for this application. However, the low strength of the PCFC makes its use for this application questionable. Recently reported unfavorable clinical results (i.e., a high incidence of pain) have led to the discontinuation of one trial of porous polyethylene. Clinical investigation of porous polysulfone-coated titanium alloy devices are in progress. Animal studies have shown bone ingrowth into porous polyethylene and porous polysulfone implants in cortical and cancellous bone and in canine femoral stems coated with these materials. Pull-out testing of porous polysulfone implants revealed that the strength of the porous material was higher than the strength of surrounding bone. Less cortical bone loss was found around porous polysulfone-coated canine stems than was reported for fully coated porous metallic prostheses, presumably because of the lower stiffness.

Animals↗
PubMed1988

Total hip arthroplasty in patients who have sickle-cell hemoglobinopathy.

Eleven patients who had a form of sickle-cell hemoglobinopathy had a total hip arthroplasty for avascular necrosis of the hip. Four patients had a revision and three had a resection arthroplasty. Four had a serious infection postoperatively. Both acute and late complications were numerous. We concluded that patients who have a sickle-cell hemoglobinopathy are at markedly increased risk for complications after total hip replacement arthroplasty, yet that over-all the results are favorable.

Adolescent↗
PubMed1988

Porous-coated femoral components in a canine model for revision arthroplasty.

UNLABELLED: Six dogs had a total hip arthroplasty during which the femoral component was coated with methacrylate and inserted in the femoral canal, after the canal had been reamed to a larger diameter than that of the femoral stem (including the coating). Thus, the implant was loose and motion was present between it and the femur in each animal. Five dogs had a revision to a prosthesis with a porous polysulfone-coated stem. This prosthesis was not cemented in place. One dog was killed before the revision for the purpose of histological examination. Although bone was present in the porous surface of all five stems at the revision, the amount was scant in three. CLINICAL RELEVANCE: A model is described for the study of cemented hip-replacement prostheses that have failed. Although variable amounts of ingrowth of bone were observed after the revision to the porous-coated prostheses without bone cement, further study is needed to determine whether adequate ingrowth of bone occurs in this model.

Animals↗
PubMed1986

Staged versus simultaneous bilateral total knee replacement.

Bilateral total knee replacements were reviewed to determine whether any difference exists in the perioperative course between procedures done under one anesthetic (simultaneous) and those done under two anesthetics (staged). There were 29 staged and 18 simultaneous cases, therefore 76 separate procedures and 94 knees done. The total operative time, blood loss, and complications were similar between the two groups. However, the staged replacements had more than twice the hospital days (34.6 +/- 7.7 vs. 16.8 +/- 5.6, P less than .001) and 18% greater hospital bills. In fact, for a given patient, the hospital bill may be greater than 50% higher if a staged rather than simultaneous replacement is done. Therefore, simultaneous replacement is recommended for appropriate patients.

Anesthetics↗
PubMed1986

A practical metaphase marker of the inactive X chromosome.

It is paradoxical that the inactivated X is the only chromosome that can be identified in the interphase nucleus, yet in metaphase, it is indistinguishable from its genetically active homolog unless special culture and staining procedures are employed. A specific inactivation-associated fold in proximal Xq resolves that paradox. We describe here how the fold in the proximal long arm can be used as a simple and reliable marker to identify the inactivated X in G-, Q-, or R-banded preparations. Several examples are given, including localization of the inactivation center to band Xq13 or q21.1, identification of nonrandom inactivation in X-chromosome rearrangements, identification of multiple active X chromosomes in tumor cell lines, analysis of X-inactivation patterns in female carriers of the fragile site at Xq27, and comparison of X-inactivation patterns among primate species.

Chromosome Banding↗
PubMed1985

Surgical reconstruction of late post-traumatic thoracolumbar kyphosis.

Thirty-four patients underwent surgery for late post-traumatic thoracolumbar kyphosis. Indications for surgery included increasing kyphotic deformity, pain, or increasing neurologic deficit. Procedures included anterior spinal fusion only, posterior spinal fusion only, anterior and posterior fusions as staged procedures, and anterior and posterior fusions under the same anesthetic. Eighteen of the patients with anterior fusions also underwent decompression of the spinal cord by resection of the vertebral body. Stable fusion with halt in progression of deformity was obtained in 33 of the 34 patients by following basic biomechanical principles.

Adolescent↗