[Show abstract][Hide abstract] ABSTRACT: Ions are released from all metals after implantation in the body through processes of corrosive and mechanical wear. The aim of this study was to investigate whether serum metal ion levels are raised in patients following total knee arthroplasty. Serum levels of chromium, cobalt, aluminium, molybdenum and zirconium were measured in two groups of patients at a minimum of 3 years after knee arthroplasty. Twenty three patients had a cobalt-chromium femoral component and 14 patients had an oxidized zirconium femoral component, acting as a control group as this femoral component is free from cobalt and chromium. All patients had the same titanium tibial base plates, and no patellae were resurfaced. Despite the lack of cobalt and chromium in the prostheses used in the control group, no statistically significant differences in serum cobalt and chromium ion levels were found between the groups. On the basis of these results there does not appear to be any significant rise in serum metal ion levels following total knee arthroplasty several years after implantation.
[Show abstract][Hide abstract] ABSTRACT: Hemiarthroplasty is a well-established treatment for displaced subcapital fracture, but controversy exists about the optimal implant type. Bipolar hemiarthroplasty has proposed advantages over unipolar hemiarthroplasty in terms of better clinical results and decreased wear of acetabular cartilage.
This study is a randomized prospective study of 51 patients (52 hips) receiving either bipolar or unipolar hemiarthroplasty for displaced subcapital fractures. The outcome measurements were clinical scores and Roentgen stereophotogrammetric analysis (RSA) analysis to determine the rate of acetabular wear.
Twenty-three patients completed 2-year follow-up. The RSA data demonstrated that there was slightly less acetabular wear by bipolar prostheses than by unipolar. The combined mean three-dimensional wear of the bipolar prostheses was 0.6 mm compared with 1.5 mm for the unipolar prostheses (P= 0.04). The bipolar group generally achieved higher scores in terms of the Harris Hip Score, Western Ontario and McMaster University Index of Osteoarthritis (WOMAC) questionnaire and 6-min walk test. These results were statistically significant at 3 months but not at 12 and 24 months.
This study suggests that while the bipolar prosthesis performs slightly better than the unipolar in terms of acetabular cartilage wear and clinical outcomes, it remains debatable whether the benefits are worth the increased cost of the prosthesis.
ANZ Journal of Surgery 04/2010; 80(4):242-6. · 1.50 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A few studies have shown that cementing the stem enhances fixation of the tibial baseplate in total knee replacement (TKR). Even the horizontal technique has been shown to provide good fixation. We used radiostereometry to study migration of the tibial component in 30 knees operated with Profix TKR. The knees were randomised for either complete (both under the baseplate and around the stem) or horizontal (only under the baseplate) cementing of the tibial component. At two years the tibial baseplate rotated externally a median of 0.18 degrees in the uncemented stem group and internally a median of 0.23 degrees in the cemented stem group. The tibial baseplate subsided 0.14 mm in the cemented stem group, and no translation was seen in the uncemented stem group. The differences in migration were small and probably without clinical significance. The findings do not favour either of the cementing techniques in TKR.
International Orthopaedics 09/2008; 33(5):1239-42. · 2.32 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Screening of musculoskeletal tissue donors with nucleic acid testing (NAT) for human immunodeficiency virus (HIV) and hepatitis C virus (HCV) has been implemented in the United States and other developed nations. However, in contrast to the donor demographics in the United States, the majority of Australian musculoskeletal tissue donations are primarily from living surgical donors. The objective of our study was to determine and compare the risk of viral infection associated with musculoskeletal tissue donation from living and nonliving donors in Australia. We studied serum samples from 12 415 consecutive musculoskeletal tissue donors between 1993 and 2004. This included 10 937 surgical donations, and 1478 donations obtained from postmortem organ donation patients and cadaveric donors. Current mandatory retesting of surgical donors 6 months postdonation reduces the risk of viral infection by approximately 95% by eliminating almost all donors in the window period. The addition of nucleic acid amplification testing for nonliving donors would similarly reduce the window period, and consequently the residual risk by approximately 50% for hepatitis B virus, 55% for HIV, and 90% for HCV. NAT, using appropriately validated assays for nonliving donors, would reduce the residual risk to levels comparable to that in living donors (where the 95% reduction for quarantining pending the 180-day re-test is included).
Transplant International 07/2008; 21(10):936-41. · 3.16 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Chondrocyte phenotype has been shown to dedifferentiate during passaged monolayer cultivation. Hence, we have investigated the expression profile of 27 chondrocyte-associated genes from both osteoarthritic cartilage tissue and healthy passaged human articular chondrocytes by quantitative real-time PCR. Our results indicate that the gene expression levels of matrix proteins and proteases in chondrocytes from monolayer culture decrease compared with those from cartilage tissue, while monolayer cultured chondrocytes from normal and osteoarthritic cartilage exhibit similar gene expression patterns. However, chondrocytic gene expression profiles were differentially altered at various stages of passage. The expression of the matrix proteins aggrecan, type II collagen, and fibromodulin inversely correlated with increasing passage number, while fibronectin and link protein exhibited a marked increase with passage. The expression of matrix proteinases MMP-3/9/13 and ADAMTS-4/5 decreased with passage, whereas proteinase inhibitors TIMP-2/3 were elevated. The cytokine IL-1 also showed increased expression with monolayer chondrocyte culture, while IGF-1 expression levels were diminished. No significant changes in TGF-beta, or the chondrogenic transcription factors Sox-9, c-fos, or c-jun were observed. Our data indicates that cultured chondrocytes undergo dedifferentiation during monolayer culture, although the gene expression level of transcription factors necessary for chondrogenesis remains unchanged. This data may prove important for the future development of more specific and efficacious cultivation techniques for human articular chondrocyte-based therapies.
Journal of Orthopaedic Research 05/2008; 26(9):1230-7. · 2.88 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Schwannomas (neurilemmomas) are benign neoplasms composed of well-differentiated Schwann cells and are usually found in the soft tissues. The occurrence of schwannomas in bone is rare, accounting for less than 0.2% of primary bone tumors. Most cases of osseous schwannoma reported in the world medical literature involve bones of the skull. Only 2 cases have previously been described in the tibia, neither of which has recurred. We report the first case of a recurrent benign solitary intraosseous schwannoma of the tibia, and detail the clinical, radiological and histological findings.
[Show abstract][Hide abstract] ABSTRACT: Higher dislocation rates have been reported with the posterior approach to the hip. Empirical studies suggest that careful repair of the posterior structures significantly reduces this risk. However, studies examining the integrity of repair using plain radiographs and metallic markers have reported high failure rates. To explain this discrepancy, we performed a study using radiostereometric analysis to assess the repair. Ten patients were recruited. Markers were placed into the capsule and bone. The capsule and conjoined short external rotators were repaired through drill holes in bone. At 3 months, stress radiostereometric analysis radiographs were taken in internal and external rotation. Eight of 10 patients had a mean of 3.51-mm difference in separation, suggesting that the repair was intact. We recommend careful repair of posterior structures when using the posterior approach to reduce the risk of dislocation.
The Journal of Arthroplasty 10/2007; 22(6):840-3. · 2.11 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Matrix-induced autologous chondrocyte implantation (MACI) has been a treatment of cartilage injury since 2000, but little is known of the histological paradigm of tissue regeneration after implantation. MACI is a stable cell-based delivery system that enables the regeneration of hyaline-like cartilage. From a cohort of 56 MACI patients, we examined the phenotype of chondrocytes seeded on type I/III collagen scaffold, and conducted progressive histologic assessment over a period of 6 months. Chondrocyte-seeded collagen scaffolds from patient implants were analyzed by electron microscopy, immunohistochemistry (type II collagen and S-100), and reverse transcription polymerase chain reaction (RT-PCR) (aggrecan and type II collagen). Coincidental cartilage biopsies were obtained at 48 hours, 21 days, 6 months, 8 months, 12 months, 18 months, and 24 months. Our data showed that chondrocytes on the collagen scaffold appeared spherical, well integrated into the matrix, and maintained the chondrocyte phenotype as evidenced by aggrecan, type II collagen, and S-100 expression. Progressive histologic evaluation of the biopsies showed the formation of cartilage-like tissue as early as 21 days, and 75% hyaline-like cartilage regeneration after 6 months. This preliminary study has suggested that MACI may offer an improved alternative to traditional treatments for cartilage injury by regenerating hyaline-like cartilage as early as 6 months after surgery.
[Show abstract][Hide abstract] ABSTRACT: One hundred four hips in 107 patients undergoing revision arthroplasty of the hip were identified at risk of dislocation and treated with the constrained cup. Radiostereometric analysis was performed to assess prosthesis migration. Mean follow-up was 3.0 years (range, 2.0-4.8). At last review, 19 patients had died and 6 were lost to follow-up. There were 5 revisions for cup loosening and a further 4 with radiographic evidence of loosening. There were 3 dislocations and 3 dissociations in 5 patients. Radiostereometric analysis demonstrated that cup migration at 24 months was up to 0.82 mm of translation and 1.58 degrees of rotation. Our results confirm that the constrained acetabular component is a highly effective option for the treatment for patients with instability of the hip. The aseptic loosening rate was higher than previously reported.
The Journal of Arthroplasty 04/2007; 22(3):377-82. · 2.11 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Analyzing skeletal kinematics with radiostereometric analysis (RSA) following corrective orthopedic surgery allows the quantitative comparison of different implant designs. The purpose of this study was to validate a technique for dynamically estimating the relative position and orientation of skeletal segments using RSA and single plane X-ray fluoroscopy. Two micrometer-based in vitro phantom models of the skeletal segments in the hip and knee joints were used. The spatial positions of tantalum markers that were implanted into each skeletal segment were reconstructed using RSA. The position and orientation of each segment were determined in fluoroscopy images by minimizing the difference between the markers measured and projected in the image plane. Accuracy was determined in terms of bias and precision by analyzing the deviation between the applied displacement protocol and measured pose estimates. Measured translational accuracy was less than 100 microm parallel to the image plane and less than 700 microm in the direction orthogonal to the image plane. The measured rotational error was less than 1 degrees . Measured translational and rotational bias was not statistically significant at the 95% level of confidence. The technique allows real-time kinematic skeletal measurements to be performed on human subjects implanted with tantalum markers for quantitatively measuring the motion of normal joints and different implant designs.
Journal of Biomechanics 02/2007; 40(3):686-92. · 2.72 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The literature contains limited yet controversial information regarding whether a fixed or a mobile bearing implant should be used in unicompartmental knee arthroplasty (UKA). This randomized study was to further document the performance and comparison of the two designs. Fifty-six knees in 48 patients (mean age of 72 years) undergoing medial UKA were randomized into a fixed bearing (Miller/Galante) or a mobile bearing (Oxford) UKA. The 2 year clinical outcomes (clinical scores), radiographic findings, and weight bearing knee kinematics (assessed using RSA) were compared between the two groups. The mobile bearing knees displayed a larger and an incrementally increased tibial internal rotation (4.3 degrees, 7.6 degrees, 9.5 degrees vs. 3.0 degrees, 3.0 degrees, 4.2 degrees respectively at 30 degrees, 60 degrees, 90 degrees of knee flexion) compared to the fixed ones. The medial femoral condyle in the mobile bearing knees remained 2 mm from the initial position vs. a 4.2 mm anterior translation in the fixed bearing knees during knee flexion. The contact point in the mobile bearing implant moved 2 mm posteriorly vs. a 6 mm anterior movement in the other group. The mobile bearing knees had a lower incidence of radiolucency at the bone implant interface (8% vs. 37%, p < 0.05). The incidence of lateral compartment OA and progression of OA at patello-femoral joint were equal. No differences were found regarding Knee Society Scores, WOMAC, and SF-36 scores (p > 0.05). This study indicates that mobile bearing knees had a better kinematics, a lower incidence of radiolucency but not yet a better knee function at 2 years.
The Knee 11/2006; 13(5):365-70. · 2.01 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We describe a new technique and aim to justify its use in total hip arthroplasty. The incision is short and there is minimal soft tissue dissection: piriformis and most of quadratus femoris remain intact. A meticulous capsular repair is performed. Patients are mobilized without restrictions. One hundred total hip arthroplasties by the standard posterior approach (group 1) were compared with 100 by the less invasive approach (group 2). Minimum follow-up was 2 years. Mean blood loss in group 1 was higher (P < .0001) and inpatient stay longer (P < .0001). There was greater improvement in WOMAC scores for up to 1 year in the less invasive group (P = .027). In conclusion, the less invasive approach is safe and the functional benefits last up to 1 year.
The Journal of Arthroplasty 10/2006; 21(7):1038-46. · 2.11 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Fibrin sealant (FS), a biological adhesive material, has been recently recommended as an adjunct in autologous chondrocyte implantation (ACI). While FS has been shown to possess osteoinductive potential, little is known about its effects on chondrogenic cells. In this study, we assessed the bioactivity of FS (Tisseel) on the migration and proliferation of human articular chondrocytes in vitro. Using a co-culture assay to mimic matrix-induced ACI (MACI), chondrocytes were found to migrate from collagen membranes towards FS within 12 h of culture, with significant migratory activity evident by 24 h. In addition, 5-bromo-2'-deoxyuridine (BrdU) incorporation experiments revealed that thrombin, the active component of the tissue glue, stimulated chondrocyte proliferation, with maximal efficacy observed at 48 h post-stimulation (1-10 U/ml). In an effort to elucidate the molecular mechanisms underlying these thrombin-induced effects, we examined the expression and activation of protease-activated receptors (PARs), established thrombin receptors. Using a combination of RT-PCR and immunohistochemistry, all four PARs were detected in human chondrocytes, with PAR-1 being the major isoform expressed. Moreover, thrombin and a PAR-1, but not other PAR-isotype-specific peptide agonists, were found to induce rapid intracellular Ca2+ responses in human chondrocytes in calcium mobilization assays. Together, these data demonstrate that FS supports both the migration and proliferation of human chondrocytes. We propose that these effects are mediated, at least in part, via thrombin-induced PAR-1 signalling in human chondrocytes.
International Journal of Molecular Medicine 05/2006; 17(4):551-8. · 1.96 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Matrix metalloproteinases (MMPs) are regarded as a significant regulator in tumor invasion and metastasis. Previous studies have shown that extracellular matrix metalloproteinase inducer (EMMPRIN) in tumor cells induces the synthesis of MMPs. EMMPRIN is abundantly present on the surface of tumor cells and stimulate adjacent stromal cells to synthesize MMPs to induce tumor progression. Giant cell tumor (GCT) of bone is a benign but locally aggressive primary neoplasm of bone. The spindle-shaped mononuclear stromal cells are considered to be the tumor components of GCT, which are capable of inducing osteoclast formation by recruiting the circulating monocyte and macrophage. In this study, we proposed that EMMPRIN is associated with the biological progression and aggressiveness of GCT. We have conducted semi-quantitative RT-PCR to determine the correlation of EMMPRIN expression with the clinical stage of GCT. We have also examined the cellular localization of EMMPRIN in GCT using in-situ hybridization (ISH) and Immunohistochemistry (IH). The results showed that EMMPRIN was present in GCT and its mRNA levels were associated with the clinical stage of GCT. Higher expression level of EMMPRIN was observed in GCT with advanced stage (stage III). There was a great significance (P < 0.05) of EMMPRIN expression between stage I & II and stage III GCTs. Both ISH and IH demonstrated that EMMPRIN is present at the multinuclear osteoclast-like giant cells of GCT, with strong immunostaining on the cell membrane. The stromal-like tumor cells were also positively stained but the intensity was weaker. Interestingly, the production of EMMPRIN in osteoclast-like cells of GCT seems to be regulated by stromal-like tumor cells. Receptor activator of NF-kappaB ligand (RANKL), which has been previously shown to be produced by the stromal-like tumor cells for the recruitment of osteoclast-like giant cells in GCT, enhanced the expression of EMMPRIN mRNA during the differentiation of macrophage-like RAW(264.7) cells into osteoclasts. In short, our studies suggest that EMMPRIN may be an important regulatory factor involved in the biological behaviors of GCT.
Journal of Cellular Biochemistry 09/2003; 89(6):1154-63. · 3.06 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Bafilomycin A1, a specific inhibitor of V-ATPases, is a potent inhibitor of bone resorption, but the underlying mechanisms of its action remain unclear. In this study, we investigated the effect of Bafilomycin A1 on endocytosis and apoptosis in RAW cells and RAW cell-derived osteoclasts. Quantitative analysis by flow cytometry showed that Bafilomycin A1 increased total transferrin levels when RAW cells were exposed to labeled transferrin and decreased the total uptake of Dextran-rhodamine B, both in a dose- and time-dependent fashion, indicating that Bafilomycin influences receptor-mediated and fluid phase endocytosis in these cells. Furthermore, Bafilomycin A1 induced apoptosis of RAW cells in a dose dependent manner as evidenced by Annexin V flow cytometry. The action of Bafilomycin A1 on endocytotic events appeared to be more sensitive and occurred earlier than on its apoptosis inducing effects, suggesting that interrupting of endocytosis might be an early sign of Bafilomycin-mediated osteoclast inhibition. Semi-quantitative RT-PCR analysis showed that the gene transcripts of putative Bafilomycin A1 binding subunit, V-ATPase-subunit a3, were expressed in the preosteoclastic RAW cell line, and up-regulated during RANKL-induced osteoclastogenesis. Osteoclasts treated with Bafilomycin A1 exhibited apoptosis as well as altered cellular localization of Transferrin Alexa 647. Given that endocytosis and apoptosis are important processes during osteoclastic bone resorption, the potent effect of Bafilomycin A1 on endocytosis and apoptosis of osteoclasts and their precursor cells may in part account for Bafilomycin A1 inhibited bone resorption.
Journal of Cellular Biochemistry 05/2003; 88(6):1256-64. · 3.06 Impact Factor