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Thomas S Thornhill

Publications and source records attributed to Thomas S Thornhill.

At least 19 recordsLinked to original sources
PubMed2006

Chondrocyte gene expression in osteoarthritis: Correlation with disease severity.

Osteoarthritis is characterized by a progressive degradation of cartilage structure and function. This study tests the hypothesis that disease severity is characterized by alterations in expression of cartilage-specific genes for aggrecan and collagen type II. Cartilage, discarded from six subjects undergoing knee replacement, was subdivided into homogeneous portions by the surgeon according to the Outerbridge classification. For four subjects, it was possible to separate the tissue into two or three fractions with different disease severity. Portions of each sample were prepared either for histological analysis and ranking according to the Mankin system or for RNA extraction. Quantitative, competitive RT-PCR assays were used for measurement of mRNA for aggrecan, collagen type II, and glyceraldehyde-3-phosphate dehydrogenase. Clinical grading was correlated with histological score (Spearman r = 0.60, p = 0.043). There was a striking decrease in expression of aggrecan and collagen II that was correlated with increase in the grade in regions of cartilage within an individual subject. In the series of 12 samples, there was an inverse correlation between aggrecan expression and osteoarthritis grade (Spearman r = -0.59, p = 0.042). In conclusion, there was an inverse relationship between regional disease severity in osteoarthritis and expression of aggrecan. Use of quantitative, competitive RT-PCR is practical for assessment of chondrocyte gene signatures.

Aged↗
PubMed2006

Comparative flexion after rotating-platform vs fixed-bearing total knee arthroplasty.

A retrospective review of rotating-platform (n = 113) and fixed-bearing (n = 100) total knee arthroplasties at a minimum 2-year follow-up was performed. All patients in both groups in this study had osteoarthritis and underwent surgery by 1 of the 2 senior authors at 1 of 2 institutions. A cruciate-retaining total knee arthroplasty was implanted with patellar resurfacing in all cases. The only difference between the 2 groups was the design of the tibial bearing and its tibial tray. Through minimization of confounding variables relating to pathology, surgeon, institution, soft-tissue balancing, and type of prosthesis, this study isolates articular design as a variable. We could not demonstrate any significant difference in knee flexion after either fixed-bearing or rotating-platform cruciate-retaining total knee arthroplasty.

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PubMed2006

Conversion of failed unicompartmental knee arthroplasty to TKA.

UNLABELLED: As the number of unicompartmental knee arthroplasties performed continues to rise, so too will the number of failures. In order to justify its continued use, conversion to total knee arthroplasty must be evaluated. From 1993-2004, 22 consecutive knees from 18 patients with a failed unicondylar knee arthroplasty underwent conversion to total knee arthroplasty. The most common modes of failure were polyethylene wear (12 patients), loosening of the femoral (4 patients) or tibial component (3 patients), and osteoarthritis progression (3 patients). All patients were converted to primary cruciate retaining components. Twenty-seven percent of patients had contained defects on the femoral condyle that required bone graft. No femoral stems or metal augmentation were required. Forty-five percent of patients had contained defects on the tibia that required bone graft. Metal wedge augmentation was required in five knees (23%), and stems were used in two patients. Sixteen of 22 knees (73%) were followed for an average of 64.5 months. Knee Society knee scores and functional scores at latest followup were 93 and 78, respectively. Conversion of a failed unicondylar knee arthroplasty to a total knee arthroplasty is technically demanding, but may be done successfully with careful preoperative planning and possible need for revision techniques. LEVEL OF EVIDENCE: Therapeutic study, level IV (case series). See the Guidelines for Authors for a complete description of levels of evidence.

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PubMed2006

Proteomics: applications to the study of rheumatoid arthritis and osteoarthritis.

The study of both DNA and protein technologies has been marked by unprecedented achievement over the last decade. The completion of the Human Genome Project in 2003 is representative of a new era in genomics; likewise, proteomics research, which has revolutionized the way we study disease, offers the potential to unlock many of the pathophysiologic mechanisms underlying the clinical problems encountered by orthopaedic surgeons. These new fields are extending our approach to and investigation of the etiology and progression of musculoskeletal disorders, notably rheumatoid arthritis and osteoarthritis. Advances in proteomics technology may lead to the development of biomarkers for both rheumatoid arthritis and osteoarthritis. Such biomarkers would improve early detection of these diseases, measure response to treatment, and expand knowledge of disease pathogenesis.

Arthritis, Rheumatoid↗
PubMed2005

Uncemented glenoid component in total shoulder arthroplasty. Survivorship and outcomes.

BACKGROUND: Glenoid component loosening continues to be a major factor affecting the long-term survivorship of total shoulder replacements. Radiolucent lines, cement fracture, migration, and loosening requiring revision are common problems with cemented glenoid components. The purpose of this study was to evaluate the results of total shoulder arthroplasty with an uncemented glenoid component and to identify predictors of glenoid component failure. METHODS: One hundred and forty-seven consecutive total shoulder arthroplasties were performed in 132 patients (mean age, 63.3 years) with use of an uncemented glenoid component fixed with screws between 1988 and 1996. One hundred and forty shoulders in 124 patients were available for follow-up at an average of 7.5 years. One shoulder in which the arthroplasty had failed at 2.4 years and for which the duration of follow-up was four years was also included for completeness. The preoperative diagnoses included osteoarthritis in seventy-two shoulders and rheumatoid arthritis in fifty-five. RESULTS: Radiolucency was noted around the glenoid component and/or screws in fifty-three of the 140 shoulders. The mean modified ASES (American Shoulder and Elbow Surgeons) score (and standard deviation) improved from 15.6 +/- 11.8 points preoperatively to 75.8 +/- 17.5 points at the time of follow-up. Eighty-five shoulders were not painful, forty-two were slightly or mildly painful, ten were moderately painful, and three were severely painful. Fifteen (11%) of the glenoid components failed clinically, and ten of them also had radiographic signs of failure. Eleven other shoulders had radiographic signs of failure but no symptoms at the time of writing. Three factors had a significant independent association with clinical failure: male gender (p = 0.02), pain (p < 0.01), and radiolucency adjacent to the flat tray (p < 0.001). In addition, the annual risk of implant revision was nearly seven times higher for patients with radiographic signs of failure. Clinical survivorship was 95% at five years and 85% at ten years. CONCLUSIONS: The failure rates of the total shoulder arthroplasties in this study were higher than those in previously reported studies of cemented polyethylene components with similar durations of follow-up. Screw breakage and excessive polyethylene wear were common problems that may lead to additional failures of these uncemented glenoid components in the future.

Adult↗
PubMed2005

Revision of unstable capitellocondylar (unlinked) total elbow replacement.

BACKGROUND: Instability is a recognized complication associated with unlinked total elbow implants. The best form of treatment of this problem is uncertain as very little has been written about it. METHODS: Twelve patients underwent operative treatment of instability at the site of a capitellocondylar unlinked total elbow replacement, and the results were reviewed retrospectively. The study group included ten women and two men with an average age of fifty-eight years. Ten patients had rheumatoid arthritis. Three elbows underwent conversion to a semi-constrained hinged prosthesis. In the other nine elbows, an attempt was made to continue with an unlinked prosthesis: three had reconstruction of one or both collateral ligaments, four had component revision, and two had both ligament reconstruction and component revision. RESULTS: After an average duration of follow-up of six years (range, two to fifteen years) only three patients had retained a functioning unlinked prosthesis. Of the remaining nine patients, three had had a conversion to a semi-constrained arthroplasty at the time of the index procedure, four had had a conversion to a semi-constrained prosthesis at the time of a salvage procedure, one had had a resection arthroplasty, and one had a painfully dislocated elbow and had declined revision. Thus, seven elbows eventually underwent conversion to a semi-constrained prosthesis; these conversion procedures were technically difficult, with perforation of the humerus occurring in six patients and perforation of the ulna occurring in four. After all procedures, the average elbow flexion was 132 degrees and the average flexion contracture was 25 degrees. According to the Mayo Elbow Performance Index, there were four excellent results, three good results, three fair results, and one poor result. CONCLUSIONS: Revision of an unlinked total elbow prosthesis to a linked total elbow prosthesis is difficult, but it restores elbow function. Although the present series documents the unpredictability of attempts to salvage an unstable unlinked prosthesis, it seems reasonable to attempt at least one soft-tissue procedure before converting to a linked prosthesis.

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PubMed2004

Dose response of the AIA rabbit stifle joint to boron neutron capture synovectomy.

This study assessed the treatment with boron neutron capture synovectomy of synovitis in the antigen-induced arthritis (AIA) model. A boron compound, potassium dodecahydrododeca-borate (K(2)B(12)H(12)), was injected into stifle joints of 24 AIA and 12 normal rabbits and activated by neutron bombardment of the joint to achieve doses from 800 to 81,000 RBE-cGy. Synovial ablation in the AIA joint was accomplished at doses of 6,000 to 7,000 RBE-cGy with no adverse effects to skin or extracapsular tissues.

Animals↗
PubMed2004

Image catalogs.

The advent of digital photography and radiography allows documentation of interesting clinical findings with unprecedented ease, and many orthopaedic surgeons have taken extensive advantage of this opportunity to create large digital libraries of clinical results. However, this leaves surgeons with a rapidly increasing volume of data to store and organize; therefore, a system for archiving, locating, and managing images, radiographs, and digital slide presentations has become a crucial need in most orthopaedic groups and practices. However, many surgical groups and practices are not familiar with the computer technology available to initiate such systems. In this review, we discuss several software solutions currently on the market to address the specific needs of orthopaedic surgeons, and as a practical example, discuss a system that is in place in the Department of Orthopaedic Surgery at our institution. Overall, depending on the individual circumstances of each institution, there are various options that meet different technologic and financial requirements.

Computer Storage Devices↗
PubMed2004

The fate of patients not returning for follow-up five years after total knee arthroplasty.

BACKGROUND: Patients who do not return for follow-up after total knee arthroplasty are often assumed to have had a worse outcome. We postulated that the Internet may be useful for locating patients who do not return for follow-up. The purpose of this study was to compare outcomes between patients who attended prescribed postoperative appointments and those who did not. METHODS: We retrospectively reviewed the outcomes for 161 patients (200 knees) at a minimum of five years after a total knee replacement. All patients who had had no contact of any type with their surgeon in any manner beyond six months following the date of the surgery were classified as not having returned for follow-up. When patients could not be located with use of all available information in their chart, a standardized Internet search algorithm was employed with use of readily available and free search engines. RESULTS: Thirty patients with thirty-five treated knees met the definition of not returning for follow-up. Thirteen patients could not be located with use of the contact information given at their last visit. All were located with use of the Internet. None of the patients had had knee surgery elsewhere. The reasons for not adhering to the prescribed postoperative regimen were identified. The group had improved Knee Society pain and function scores compared with the preoperative values, and the patients were not significantly different from those who did return for follow-up. CONCLUSIONS: The patients who did not attend follow-up appointments in this series had not had any additional surgery and did not have any significant differences in measured outcome variables when compared with patients who had complied with a follow-up protocol. The Internet proved to be a valuable tool for locating patients who had not returned for follow-up postoperatively.

Adult↗
PubMed2003

A comparative study of the inhibitory effects of interleukin-1 receptor antagonist following administration as a recombinant protein or by gene transfer.

Anakinra, the recombinant form of IL-1 receptor antagonist (IL-1Ra), has been approved for clinical use in the treatment of rheumatoid arthritis as the drug Kineret trade mark, but it must be administered daily by subcutaneous injection. Gene transfer may offer a more effective means of delivery. In this study, using prostaglandin E2 production as a measure of stimulation, we quantitatively compared the ability of anakinra, as well as that of IL-1Ra delivered by gene transfer, to inhibit the biologic actions of IL-1beta. Human synovial fibroblast cultures were incubated with a range of doses of anakinra or HIG-82 cells genetically modified to constitutively express IL-1Ra. The cultures were then challenged with recombinant human IL-1beta either simultaneously with addition of the source of IL-1Ra or 24 hours later. In a similar manner, the potencies of the two sources of IL-1Ra were compared when human synovial fibroblasts were challenged with IL-1beta produced constitutively by genetically modified cells. No significant difference in inhibitory activity was observed between recombinant protein and IL-1Ra provided by the genetically modified cells, under static culture conditions, even following incubation for 4 days. However, under culture conditions that provided progressive dilution of the culture media, striking differences between these methods of protein delivery became readily apparent. Constitutive synthesis of IL-1Ra by the genetically modified cells provided sustained or increased protection from IL-1 stimulation over time, whereas the recombinant protein became progressively less effective. This was particularly evident under conditions of continuous IL-1beta synthesis.

Animals↗
PubMed2003

Paradoxic cerebral embolism after cemented knee arthroplasty: a report of 2 cases and prophylactic option for subsequent arthroplasty.

Major orthopaedic procedures that involve instrumentation of the medullary canal are well known to produce showers of embolic debris including fat, bone fragments, marrow constituents, and cement. A growing literature has identified paradoxic cerebral embolism as a rare but serious consequence of the passage of these emboli through an intracardiac right-to-left shunt to the cerebral arterial circulation. We report 2 cases of paradoxic cerebral embolism after cemented total knee arthroplasty and propose a novel treatment plan to prevent recurrent stroke during subsequent surgery.

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PubMed2003

Osteoporosis and vitamin-D deficiency among postmenopausal women with osteoarthritis undergoing total hip arthroplasty.

BACKGROUND: Several epidemiological studies have shown a lower prevalence of osteoporotic hip fractures in patients with osteoarthritis. Other studies have demonstrated elevated bone mineral density in patients with osteoarthritis. The prevailing view is that there may be an inverse relationship between osteoarthritis and osteoporosis. The purposes of the present study were to describe a subgroup of patients with osteoarthritis who were found to have osteoporosis and to assess the vitamin-D status and other risk factors for low bone density in osteoarthritic subjects with and without osteoporosis. METHODS: The bone mineral density of the spine, the proximal part of the femur, and the total body was measured with dual-energy x-ray absorptiometry in sixty-eight postmenopausal white women who were scheduled to undergo total hip replacement for advanced osteoarthritis. The serum levels of 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, intact parathyroid hormone, osteocalcin, and bone-specific alkaline phosphatase and the urinary level of N-telopeptide were measured. Information from validated lifestyle, dietary, and demographic questionnaires was also evaluated. RESULTS: Seventeen (25%) of the sixty-eight women had occult osteoporosis (as indicated by a T score of less than -2.5). Fifteen (22%) of the sixty-eight subjects had vitamin-D deficiency, and three (4%) had an elevated serum parathyroid hormone level. Only two of the seventeen osteoporotic women had vitamin-D deficiency. On the basis of these numbers, vitamin-D status was not correlated with bone density (p = 0.32). Analysis of the relationship between the number of years since menopause and osteoporosis or markers of elevated bone turnover showed that osteoporosis was detected throughout the postmenopausal period. CONCLUSION: A substantial portion of these sixty-eight white women with osteoarthritis of the hip had occult osteoporosis and hypovitaminosis D. Vitamin-D deficiency was not restricted to the group with low bone density. These results support the need to consider the presence of both osteoporosis and vitamin-D deficiency in women with advanced osteoarthritis.

Absorptiometry, Photon↗