Biomedical subjects

Jonathan P Garino

Publications and source records attributed to Jonathan P Garino.

9 recordsLinked to original sources

PubMed2006

Impaction allografting for massive femoral defects in revision hip arthroplasty using collared textured stems.

We present a prospective study of impaction grafting using collared textured stems in femurs with massive defects (defined as requiring >150 cm(3) of cancellous allograft). Eighteen hips were followed for a minimum of 2 years. Average Harris hip scores increased from 50 preoperatively to 83 at most recent follow-up. Seventeen hips were functioning well at the time of most recent follow-up and exhibited no stem subsidence or aseptic loosening. One hip was associated with visible subsidence and required further revision. Single-photon emission computed tomography analyses performed at an average of 37 months indicated active graft reorganization in all cases studied. Impaction allografting with collared textured stems for massive defects demonstrates good intermediate-term clinical results and may be a useful alternative to allograft stem composites and megaprostheses.

Adult↗

PubMed2006

Comparison of fluorodeoxyglucose positron emission tomography and (111)indium-white blood cell imaging in the diagnosis of periprosthetic infection of the hip.

We aimed to compare the accuracy of fluorodeoxyglucose positron emission tomography (FDG-PET) with technetium-99m sulfur colloid (111)indium-labeled white blood cell scintigraphy (TcSC-Ind BM/WBC) in diagnosis of periprosthetic infection. Eighty-nine patients with 92 painful hip prostheses were recruited prospectively and given the option of undergoing either combined FDG-PET and TcSC-Ind BM/WBC or FDG-PET only. FDG-PET correctly diagnosed 20 of the 21 infected cases (sensitivity, 95.2%) and ruled out infection in 66 of the 71 aseptic hips (specificity, 93%) corresponding to a positive predictive value of 80% (20/25) and a negative predictive value of 98.5% (66/67). TcSC-Ind BM/WBC correctly identified 5 of the 10 infected cases (sensitivity, 50%) and 39 of 41 aseptic cases (specificity, 95.1%) corresponding to a positive and negative predictive values of 41.7% (5/12 cases) and 88.6% (39/44 cases), respectively. Based on these preliminary results, FDG-PET appears to be a promising diagnostic tool for distinguishing septic from aseptic painful hip prostheses.

Adult↗

PubMed2006

Determining lesion size in osteonecrosis of the femoral head.

BACKGROUND: Several studies have documented that the size of the osteonecrotic lesion in the femoral head is an essential parameter in determining prognosis and treatment. There are several methods currently available to measure lesion size, but no general agreement as to which is most useful. In the present study, three different radiographic methods for determining lesion size were evaluated and compared. METHODS: Anteroposterior and lateral radiographs of forty-two hips with osteonecrosis were examined. The extent of osteonecrotic involvement of the femoral head was determined through the use of three different methods: the volume of necrosis by quantitative digital image analysis, and the angular measurements described by Kerboul et al. and Koo and Kim. Graphs were constructed to demonstrate these relationships. RESULTS: Volumetric measurement appeared to be the most reliable. There was only a rough correlation with angular measurements. Several sources of error were noted when simple angular measurements of irregular, three-dimensional lesions were used. The Kerboul method routinely overestimated lesion size and designated 81% of the lesions as "large." The modified Koo and Kim method provided a more even distribution of lesion size and correlated with volumetric measurements in 74% of hips (thirty-one of forty-two hips). CONCLUSIONS: Quantitative volumetric measurements appear to be the most reliable method to measure the true size of a three-dimensional osteonecrotic lesion of the femoral head. Volumetric measurement is more accurate than angular measurement and can be performed easily with modern technology. Angular measurements, although somewhat simpler to use than volumetric measurements, may provide only a rough estimate of lesion size, partly due to the considerable differences in outline or location of the necrotic segments. Nevertheless, determination of lesion size must be part of a comprehensive system of staging of this disease, which includes the evaluation of other parameters, such as the extent and degree of articular surface involvement and the status of the hip joint and the acetabulum. LEVEL OF EVIDENCE: Diagnostic Level III. See Instructions to Authors on jbjs.org for a complete description of levels of evidence.

Body Weights and Measures↗

PubMed2004

Hemoglobin substitutes.

Orthopaedic patients frequently require blood transfusions to treat peri-operative anemia. Research in the area of hemoglobin substitutes has been of great interest since it holds the promise of reducing the reliance on allogeneic blood transfusions. The three categories of hemoglobin substitutes are (1) cell-free, extracellular hemoglobin preparations made from human or bovine hemoglobin (hemoglobin-based oxygen carriers or HBOCs); (2) fluorine-substituted linear or cyclic carbon chains with a high oxygen-carrying capacity (perfluorocarbons); and (3) liposome-encapsulated hemoglobin. Of the three, HBOCs have been the most extensively studied and tested in preclinical and clinical trials that have shown success in diminishing the number of blood transfusions as well as an overall favorable side-effect profile. This has been demonstrated in vascular, cardiothoracic, and orthopaedic patients. HBOC-201, which is a preparation of cell-free bovine hemoglobin, has been approved for clinical use in South Africa. These products may well become an important tool for physicians treating peri-operative anemia in orthopaedic patients.

Anemia↗

PubMed2003

Regulation of BMP-induced transcription in cultured human bone marrow stromal cells.

BACKGROUND: Adherent bone marrow stromal cells are inducible osteoprogenitors, giving rise to cells expressing osteoblast markers including alkaline phosphatase, osteopontin, osteocalcin, and bone sialoprotein. However, the potency of inducers varies in a species-specific manner. Glucocorticoids such as dexamethasone induce alkaline phosphatase activity in both human and rat mesenchymal stem cells, while mouse bone marrow stromal cells are refractory to dexamethasone-induced alkaline phosphatase activity. In contrast, BMP induces alkaline phosphatase activity in both mouse and rat bone marrow stromal cells, while BMP effects on human bone marrow stromal cells are poorly characterized. METHODS: Bone marrow samples were isolated from patients undergoing hip replacement. Mononuclear marrow cells were cultured and grown to confluence without or with 10 (-7) M dexamethasone. Cells from each isolate were passaged into medium containing 100 micro g/mL ascorbate phosphate and treated with dexamethasone, 100 ng/mL BMP, or no inducer. At day 6, alkaline phosphatase activity was assayed, and RNA was prepared for mRNA analyses by real-time polymerase chain reaction. RESULTS: Bone marrow stromal cells from twenty-four of twenty-six patients showed no significant osteogenic response to BMP-2, 4, or 7 as determined by alkaline phosphatase induction. However, BMPs induced elevated levels of other genes associated with osteogenesis such as bone sialoprotein and osteopontin as well as BMP-2 and noggin. If primary cultures of human bone marrow stromal cells were pretreated with dexamethasone, BMP-2 treatment of first-passage cells induced alkaline phosphatase in approximately half of the isolates, and significantly greater induction was seen in cells from males. Dexamethasone treatment, like BMP treatment, also increased expression of the BMP-binding protein noggin. CONCLUSIONS: Most human femur bone marrow stromal cell samples appear incapable of expressing elevated alkaline phosphatase levels in response to BMPs. Since BMP treatment induced expression of several other BMP-regulated genes, the defect in alkaline phosphatase induction is presumably not due to impaired BMP signaling. We hypothesize that the mechanism by which BMPs modulate alkaline phosphatase expression is indirect, involving a BMP-regulated transcription factor for alkaline phosphatase expression that is controlled differently in humans and rodents.

Alkaline Phosphatase↗

PubMed2003

Alternative bearing surfaces in total hip arthroplasty.

Polyethylene wear and extension of indications of total hip arthroplasty into younger and younger age groups have pushed manufacturers to develop more durable bearing surfaces. Standard polyethylene, the plastic used for the first 3 decades of hip replacement, virtually ceases to exist in its original form. Modifications of the processing, including sterlization in an inert environment and cross-linking, have demonstrated some improvements in wear. Hard-on-hard bearings such as ceramic-on-ceramic and metal-on-metal also have demonstrated extremely low wear. This article reviews the pros and cons of the alternative bearing options available to assist in the proper bearing selection for a particular patient.

Aluminum Oxide↗

PubMed2002

Persistent non-specific FDG uptake on PET imaging following hip arthroplasty.

Hip arthroplasty is a common surgical procedure, but the diagnosis of infection associated with hip arthroplasty remains challenging. Fluorine-18 fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) has been shown to be a promising imaging modality in settings where infection is suspected. However, inflammatory reaction to surgery can result in increased FDG uptake at various anatomic locations, which may erroneously be interpreted as sites of infection. The purpose of this study was to assess the patterns and time course of FDG accumulation following total hip replacement over an extended period of time. Firstly, in a prospective study nine patients with total hip replacement were investigated to determine the patterns of FDG uptake over time. Three FDG-PET scans were performed in each patient at about 3, 6 and 12 months post arthroplasty. Secondly, in a retrospective analysis, the medical and surgical history and FDG-PET imaging results of 710 patients who had undergone whole-body scans for the evaluation of possible malignant disorders were reviewed. The history of arthroplasty and FDG-PET findings in the hip region were reviewed for this study. Patients with symptomatic arthroplasties or related complaints during FDG-PET scanning were excluded from the analysis. During the entire study period, all nine patients enrolled in the prospective study were demonstrated to have increased FDG uptake around the femoral head or neck portion of the prosthesis that extended to the soft tissues surrounding the femur. Among the patients reviewed in the retrospective study, 18 patients with a history of 21 hip arthroplasties who were asymptomatic at the time of FDG-PET scan met the criteria for inclusion. The time interval between the hip arthroplasty and the FDG-PET study ranged from 3 months to 288 months (mean+/-SD: 80.4+/-86.2 months). In 81% (17 of 21) of these prostheses, increased FDG uptake could be noted around the femoral head or neck portion of the prosthesis. The average time interval between arthroplasty and FDG-PET scan in these patients was 71.3 months. In only four prostheses (19%, 4 of 21) was no abnormally increased FDG uptake seen around the prostheses or adjacent sites. The average time interval in these patients was 114.8 months. It is concluded that following hip arthroplasty, non-specifically increased FDG uptake around the head or neck of the prosthesis persists for many years, even in patients without any complications. Therefore, to minimize the number of false-positive results for infection with PET studies obtained to evaluate a painful hip prosthesis, caution should be exercised when interpreting FDG uptake around the head or neck portion of the prosthesis.

Arthroplasty, Replacement, Hip↗

PubMed2002

The use of impaction grafting in revision total knee arthroplasty.

Impaction grafting has been used successfully in revision total knee arthroplasty. Histology and preliminary clinical results show that this technique may be useful in situations in which bone loss is extensive. In contrast to bulk allografts, morcellized graft remodels and incorporates with the host. The preliminary results and technique are reviewed briefly.

Arthroplasty, Replacement, Knee↗

PubMed2002

Early failure of precoated femoral components in primary total hip arthroplasty.

BACKGROUND: In an effort to decrease the rate of aseptic loosening, certain cemented femoral components were designed to have a roughened or textured surface with a methylmethacrylate precoating. Reports differ as to whether this step has increased or decreased the rate of failure. This study was designed to evaluate this issue. METHODS: Five hundred and fourteen hips treated with a cemented Harris Precoat stem (Zimmer, Warsaw, Indiana) were evaluated clinically and radiographically and compared with 254 hips treated with an uncoated Harris Design-2 stem (Howmedica, East Rutherford, New Jersey). Prostheses that had been removed at revision were examined. The cementing and surgical techniques were identical and the population demographics were similar for these two groups. RESULTS: The mean durations of follow-up were 8.4 and 13.5 years for the Precoat and uncoated Design-2 stems, respectively. At those times, at least forty-nine (9.5%) of the 514 Precoat components and at least ten (3.9%) of the 254 uncoated Design-2 stems had failed (p = 0.006). Five Precoat stems fractured, and no uncoated Design-2 stems fractured. Component failure was associated with use in young, active, heavy men with a diagnosis of avascular necrosis and generally with the use of smaller components. The cementing technique was satisfactory in the majority of the patients, and there were no qualitative differences in cementing technique between the hips that failed and those that did not. The mechanisms of failure of the Precoat prostheses included bone-cement loosening, focal osteolysis, stem fracture, and prosthesis-cement debonding. Fractures of smaller components occurred as a result of fatigue failure and were associated with good distal fixation but proximal stem loosening. CONCLUSIONS: The rate of failure of roughened, precoated, cemented femoral components was considerably higher and occurred earlier than that of femoral components that were neither textured nor precoated with methylmethacrylate. Younger patients with avascular necrosis had a higher risk of failure; however, this factor alone did not completely explain the differences in outcome between these two components. The causes of aseptic loosening are multifactorial and may be related to component design and size as well as to precoating and surface finish.

Adult↗