Biomedical subjects

M J Cross

Publications and source records attributed to M J Cross.

At least 19 recordsLinked to original sources

PubMed2007

Osteochondritis dissecans of the knee; long-term clinical outcome following arthroscopic debridement.

We reviewed 32 knees in 26 patients who had previously undergone arthroscopic debridement for symptomatic osteochondritis dissecans (OCD) of the knee. The patients were followed up at a minimum of 11 years following surgery and were evaluated clinically using the American Knee Society Clinical Rating Score. Additional evaluation was performed using the Hughston Scale to include radiographic assessment. The mean American Knee Society Score was 179 (out of 200), indicating good clinical function. Radiographically, however, only 29% scored excellent or good on the Hughston Scale. Younger patients with a small, stable (and therefore preserved), medial femoral condyle lesion had the best prognosis. Whilst more novel and complex options such as chondrocyte implantation are being assessed for the treatment of OCD, it is clear that within this study group careful debridement with removal of loose tissue can achieve good clinical results in the long term. There was however radiographic evidence of early degenerative joint disease in 17/24 (71%) of patients reviewed. Patients undergoing excision of OCD fragments did worse than those in whom the fragment was preserved, however the risk of further surgery is raised if a fragment is left in situ at initial surgery.

Adolescent↗

PubMed2006

A comparison of bilateral uncemented total knee arthroplasty: simultaneous or staged?

In a series of 1304 patients (1867 knees), the results of simultaneous and staged bilateral total knee arthroplasty were compared with each other and with unilateral total knee arthroplasty. The bilateral procedures had a significantly higher rate of complications than unilateral procedures, almost entirely because of thromboembolic problems. However, this did not correspond to an increase in mortality. If a bilateral procedure was indicated, then a simultaneous procedure had no increased risk over a staged procedure. There was no increase in cardiovascular complications, the rate of deep-vein thrombosis or pulmonary embolism or mortality. The rate of infection was lower with a bilateral procedure and the overall revision rate was less than 1% in all groups. The prosthesis functioned as well in all groups in the medium and longer term periods. We feel that simultaneous bilateral total knee arthroplasty is a safe and successful procedure when compared with a staged bilateral procedure. It also has the added benefit of single anaesthetic, reduced costs and decreased total recovery time when compared to a staged bilateral procedure. For these reasons it should be considered as an option in the presence of bilateral knee joint disease.

Aged↗

PubMed2006

Five- to 12-year follow-up of a hydroxyapatite-coated, cementless total knee replacement in young, active patients.

We carried out a prospective study of 118 hydroxyapatite-coated, cementless total knee replacements in patients who were </= 55 years of age and who had primary (92; 78%) or post-traumatic (26; 22%) osteoarthritis. The mean period of follow-up was 7.9 years (5 to 12.5). The Knee Society clinical scores improved from a pre-operative mean of 98 (0 to 137) to a mean of 185 (135 to 200) at five years, and 173 (137 to 200) at ten years. There were two revisions of the tibial component because of aseptic loosening, and one case of polyethylene wear requiring further surgery. There was no osteolysis or progressive radiological loosening of any other component. At 12 years, the overall rate of implant survival was 97.5% (excluding exchange of spacer) and 92.1% (including exchange of spacer). Cementless total knee replacement can achieve excellent long-term results in young, active patients with osteoarthritis. In contrast to total hip replacement, polyethylene wear, osteolysis and loosening of the prosthesis were not major problems for these patients, although it is possible that this observation could change with longer periods of follow-up.

Adult↗

PubMed2005

Robust allele-specific polymerase chain reaction markers developed for single nucleotide polymorphisms in expressed barley sequences.

Many methods have been developed to assay for single nucleotide polymorphisms (SNPs), but generally these depend on access to specialised equipment. Allele-specific polymerase chain reaction (AS-PCR) is a method that does not require specialised equipment (other than a thermocycler), but there is a common perception that AS-PCR markers can be unreliable. We have utilised a three primer AS-PCR method comprising of two flanking-primers combined with an internal allele-specific primer. We show here that this method produces a high proportion of robust markers (from candidate allele specific primers). Forty-nine inter-varietal SNP sites in 31 barley (Hordeum vulgare L.) genes were targeted for the development of AS-PCR assays. The SNP sites were found by aligning barley expressed sequence tags from public databases. The targeted genes correspond to cDNAs that have been used as restriction fragment length polymorphic probes for linkage mapping in barley. Two approaches were adopted in developing the markers. In the first approach, designed to maximise the successful development of markers to a SNP site, markers were developed for 18 sites from 19 targeted (95% success rate). With the second approach, designed to maximise the number of markers developed per primer synthesised, markers were developed for 18 SNP sites from 30 that were targeted (a 60% success rate). The robustness of markers was assessed from the range of annealing temperatures over which the PCR assay was allele-specific. The results indicate that this form of AS-PCR is highly successful for the development of robust SNP markers.

Alleles↗

PubMed2005

Patient self-efficacy and health locus of control: relationships with health status and arthritis-related expenditure.

OBJECTIVE: To explore the relationship between measures of self-efficacy, health locus of control, health status and direct medical expenditure among community-dwelling subjects with rheumatoid arthritis (RA) and osteoarthritis (OA). METHODS: This analysis is part of a larger ongoing study of the costs and outcomes of arthritis and its treatments. Community-dwelling RA and OA respondents completed questionnaires concerning arthritis-related expenditure, health status, arthritis related self-efficacy and health locus of control. RESULTS: Data were obtained from 70 RA respondents and 223 OA respondents. The majority of respondents were female with a mean age of 63 yr for RA respondents and 68 yr for OA respondents. Among the RA respondents, those with higher self-efficacy reported better health status and lower overall costs. Health locus of control was not consistently correlated with health status. OA respondents with higher self-efficacy reported better health status and lower costs. Health locus of control had more influence. OA respondents with higher external locus of control reported worse pain and function. A higher belief in chance as a determinant of health was correlated with more visits to general practitioners and a higher cost to both the respondent and the health system. CONCLUSION: Higher self-efficacy, which is amenable to change through education programmes, was associated with better health status and lower costs to the respondent and the health system in this cross-sectional study. Locus of control had less of an influence; however, the tendency was for those with higher external locus of control to have higher costs and worse health status. As the measurement of these constructs is simple and the outcome potentially affects health status, these results have implications for future intervention studies to improve quality of life and reduce the financial impact of arthritis on both the health-care system and patients.

Arthritis, Rheumatoid↗

PubMed2005

Results of open arthrolysis for the treatment of stiffness after total knee replacement.

Stiffness is an uncommon but potentially debilitating complication following total knee replacement (TKR). The treatment of this condition remains difficult and controversial. We present the results of 13 patients who underwent open arthrolysis for stiffness. The mean time between TKR and arthrolysis was 14 months. The mean follow-up was 7.2 years (2 to 10). The mean range of movement prior to arthrolysis was 55 degrees . This increased to 91 degrees , six months after arthrolysis (p < 0.005). The improved range of movement was maintained during the follow-up period. No patient has required revision of their components. We have found arthrolysis to be a useful and successful approach to post-TKR stiffness.

Aged↗

PubMed2005

A hydroxyapatite-coated total knee replacement: prospective analysis of 1000 patients.

We prospectively reviewed 1000 consecutive patients who underwent a cementless, hydroxyapatite-coated, stemless, total knee replacement over a period of nine years. Regular post-operative clinical follow-up was performed using the Knee Society score. The mean pre-operative score was 96, improving to 182 and 180 at five and ten years, respectively. To date, there have been seven (0.5%) cases which required revision, primarily for septic loosening (four cases), with low rates of other post-operative complications. The cumulative survival at ten years with revision as the end-point, was 99.14% (95% confidence interval 92.5 to 99.8). These results support the use of hydroxyapatite in a cementless total knee replacement since it can give reliable fixation with an excellent clinical and functional outcome.

Adult↗

PubMed2004

Two knees or not two knees? Patient costs and outcomes following bilateral and unilateral total knee joint replacement surgery for OA.

AIMS: This study aims to address medical and non-medical direct costs and health outcomes of bilateral and unilateral total knee replacement from the patients' perspective during the first year post-surgery. METHODS: Osteoarthritis patients undergoing primary unilateral total knee or bilateral total knee replacement (TKR) surgery at three Sydney hospitals were eligible. Patients completed questionnaires pre-operatively to record expenses during the previous three months and health status immediately prior to surgery. Patients then maintained detailed prospective cost diaries and completed SF-36 and WOMAC Index each three months for the first post-operative year. RESULTS: Pre-operatively, no significant differences in health status were found between patients undergoing unilateral TKR and bilateral TKR. Both unilateral and bilateral TKR patients showed improvements in pain, stiffness and function from pre-surgery to 12 months post-surgery. Patients who had bilateral TKR spent an average of 12.3 days in acute hospital and patients who had unilateral TKR 13.6 days. Totally uncemented prostheses were used in 6% of unilateral replacements and 48% of bilateral replacements. In hospital, patients who had bilateral TKR experienced significantly more complications, mainly thromboembolic, than patients who had unilateral TKR. Regression analysis showed that for every one point increase in the pre-operative SF-36 physical score (i.e. improving physical status) out-of-pocket costs decreased by 94%. Out-of-pocket costs for female patients were 3.3 times greater than for males. CONCLUSION: Patients undergoing bilateral TKR and unilateral TKR had a similar length of stay in hospital and similar out-of-pocket expenditures. Bilateral replacement patients reported better physical function and general health with fewer health care visits one year post procedure. Patients requiring bilateral TKR have some additional information to aid their decision making. While their risk of peri-operative complications is higher, they have an excellent chance of good health outcomes at 12 months and are not going to be doubly "out-of-pocket" for the experience.

Aged↗

PubMed2004

Hydroxyapatite-coated, cementless total knee replacement in patients aged 75 years and over.

We have carried out a prospective study comparing the results at five years in patients older than 75 years of age undergoing hydroxyapatite-coated, cementless total knee replacement (TKR) with those who were younger. The Knee Society clinical rating scores were recorded before and after operation. Of 559 patients undergoing TKR, 135 were in the elderly age group. The knee scores at five years or more showed comparable results, with patients under 75 years of age reaching a score of 183 and those aged 75 years or over reaching 174. These differences were predominantly due to the functional component of the score. We conclude that elderly patients do just as well as the younger group using this prosthesis.

Adult↗

PubMed2004

Arthroscopic debridement in the treatment of the infected total knee replacement.

Infection is a potentially disastrous complication of total knee replacement (TKR). Retention of the prosthesis has been associated with high rates of persistent infection. Our study shows that in selected situations, arthroscopic debridement may allow retention of the prosthesis and eradication of the infection. However, the prosthesis must be stable, the surgical technique must be meticulous and specific antibiotics must be taken for a lengthy period. Arthroscopic debridement should be considered as an alternative to an open technique, or revision, for the infected TKR.

Aged↗

PubMed2003

Meniscal bearing uncemented total knee arthroplasty: early clinical results at a minimum 2-year review.

A prospective study of early clinical and radiologic outcome of the Motus (Osteo, Selzach, Switzerland) meniscal bearing total knee arthroplasty was performed. We reviewed the first 75 consecutive prostheses in 62 patients, implanted over a 4-year period. The mean follow-up was 2.5 years. Average preoperative knee score was 97 out of 200 (Knee Society score, 43; functional score, 54) and at 2-year review was 179 out of 200 (Knee Society score, 87; functional score, 92). Average postoperative flexion at 2 years was 113 degrees. No meniscal bearing subluxation, dislocation, or breakages occurred. Radiologically, there was no evidence of subsidence or osteolysis. Our results support the continued use of this meniscal bearing knee prosthesis. It is important to confirm, however, an equal flexion and extension gap without proximal joint line migration.

Aged↗

PubMed2002

Living with rheumatoid arthritis: expenditures, health status, and social impact on patients.

OBJECTIVE: To determine costs related to living with rheumatoid arthritis (RA), and to identify the association between health status-as measured by the Health Status Questionnaire short form-36 (SF-36) and the disease specific index Health Assessment Questionnaire (HAQ)-and the social impact of RA. METHODS: A prospective cohort study was carried out on 81 patients with RA who completed four consecutive three month cost diaries. The SF-36, HAQ, and social impact at baseline and one year follow up were also assessed. RESULTS: Women reported worse SF-36 physical function and HAQ scores than men and received more assistance from family and friends. Women spent more on non-prescription medication and devices to assist them than men. Older patients had higher expenditure on visits to health professionals, whereas younger patients spent more on prescription medication and tests. Pension status and membership of private health insurance schemes were important determinants in these differences in expenditure. CONCLUSION: Costs increased with duration of disease, those with private health insurance had greater out of pocket costs (excluding membership fees), and those with pension support had fewer costs. Women were more affected by RA than men in health status, social impact, and out of pocket costs.

Adult↗

PubMed2002

Ability to kneel after total knee replacement.

We have investigated the ability to kneel after total knee replacement. We asked 75 patients (100 knees) at least six months after routine uncemented primary total knee replacement, to comment on and to demonstrate their ability to kneel. Differences between the perceived and actual ability to kneel were noted. In 32 knees patients stated that they could kneel without significant discomfort. In 54 knees patients avoided kneeling because of uncertainties or recommendations from third parties (doctors, nursing staff, friends, etc). A total of 64 patients was actually able to kneel without discomfort or with mild discomfort only and 12 of the remainder were unable to kneel because of problems which were not related to the knee. Twenty-four patients therefore were unable to kneel because of discomfort in the knee. There was no difference between the 'kneelers' and 'non-kneelers' with regard to overall knee score, range of movement and the presence of patellar resurfacing.

Adult↗

PubMed2001

Living with osteoarthritis: patient expenditures, health status, and social impact.

OBJECTIVE: To determine "out-of-pocket" expenditures related to osteoarthritis (OA) and to explore whether demographic details, health status scores (Medical Outcomes Study 36-item Short Form [SF-36] and Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC]), or perception of social effect were expenditure determinants. METHODS: A prospective cohort study of community-dwelling subjects with OA completed 4 consecutive 3-month cost diaries. In addition, subjects completed the SF-36 and WOMAC at baseline and at 12 months. Social impact at baseline was collected. Four groups categorized by age and sex were compared. Patients undergoing joint replacement were excluded. RESULTS: Differences in health status were defined more by age than by sex, especially for physical function. The costs to the patients were high, particularly for women, who spent more on medications and special equipment. Women also reported receiving more assistance from family and friends. Higher disease-related expenditures were associated with greater pain levels, poorer social function and mental health, and longer duration of disease. Significant independent predictors of total patient expenditures related to OA were being female and having joint stiffness. CONCLUSION: Despite having heavily subsidized health care and access to the Pharmaceutical Benefits Scheme, out-of-pocket costs for patients with OA in Australia are considerable. Higher expenditures for patients with OA are related to more advanced disease, especially for women.

Aged↗

PubMed2001

FGF and VEGF function in angiogenesis: signalling pathways, biological responses and therapeutic inhibition.

Angiogenic growth factors such as fibroblast growth factors (FGFs) and vascular endothelial growth factors (VEGFs) are currently targets of intense efforts to inhibit deregulated blood vessel formation in diseases such as cancer. FGFs and VEGFs exert their effects via specific binding to cell surface-expressed receptors equipped with tyrosine kinase activity. Activation of the receptor kinase activity allows coupling to downstream signal transduction pathways that regulate proliferation, migration and differentiation of endothelial cells. Inhibitors of FGF and VEGF signalling are currently in clinical trials. In this article, the current knowledge of FGF- and VEGF-induced signal transduction that leads to specific biological responses will be summarized. Furthermore, the manner in which this knowledge is being exploited to regulate angiogenesis will be discussed.

Binding Sites↗

PubMed2001

A comparison of outcomes in osteoarthritis patients undergoing total hip and knee replacement surgery.

OBJECTIVE: The aims of this study were to assess changes in physical function and quality of life with the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the instrument of the Medical Outcomes Study SF-36 Health Survey (MOS SF-36), respectively, in patients undergoing hip anf knee joint replacement surgery and to compare the responsiveness of these two outcome measures 1 year after surgery. DESIGN: One hundred and ninety-four patients with osteoarthritis (OA knee 108, OA hip 86) admitted to four hospitals in Sydney were followed over a period of 1 year at 3 monthly intervals. RESULTS: WOMAC measures improved significantly after 1 year for OA hip and OA knee: there was reduction in pain of 71% and 53%, reduction of stiffness of 55% and 43% and improvement in physical function of 68% and 43%, respectively. MOS SF-36 measures in those having hip surgery improved significantly for pain (222%), physical function (247%), physical role functioning (402%), general health (110%), vitality (143%0, social functioning (169%) and mental health (114%). For those in the knee surgery group, significant improvement was seen for pain (175%), physical function (197%), physical role functioning (275%), vitality (125%) and social functioning (119%). The WOMAC was a more responsive measure than the MOS SF-36. CONCLUSION: WOMAC and MOS SF-36 detect significant and clinically meaningful changes in outcome after hip and knee replacement. WOMAC requires a smaller sample size and is more responsive in the short term. For a follow-up longer than 6 months MOS SF-36 provides additional information. The improvement in outcomes following hip joint surgery were significantly greater than those following knee surgery.

Aged↗

PubMed2000

Subareolar injection is a better technique for sentinel lymph node biopsy.

BACKGROUND: Numerous techniques and materials show accuracy in localizing the sentinel lymph node (SLN). We hypothesized that subareolar injection of material would localize the SLN as effectively as peritumoral injection. METHODS: Thirty-eight patients were injected with technetium-99 sulfur colloid either peritumorally or subareolarly in addition to the injection of blue dye around the tumor. Radioactive SLNs were localized using a hand-held gamma probe. RESULTS: Nineteen patients were included in each of the two groups, peritumoral and subareolar. SLNs were found in all patients injected subareolarly and in 18 of 19 injected peritumorally. The false-negative rate was 20% for peritumoral injection and 0% for subareolar injection. CONCLUSION: The results suggest that subareolar injection was as accurate, if not more accurate, than peritumoral injection for localizing the SLN. This technique is simpler than peritumoral injection and does not require injection under image guidance for nonpalpable lesions.

Adult↗

PubMed2000

Determinants of willingness to pay for hip and knee joint replacement surgery for osteoarthritis.

OBJECTIVES: To determine whether patients with osteoarthritis (OA) would be willing to pay for joint replacement and whether patient characteristics or health outcomes, including pain, physical function and health-related quality of life, were related to willingness to pay (WTP). METHODS: Patients who had undergone primary total hip replacement (THR) or total knee replacement (TKR) for OA completed a disease-specific questionnaire (Western Ontario and McMaster: WOMAC index), a generic measure of health status (Medical Outcome Study Short Form-36: SF-36) and an Evaluation Questionnaire to measure WTP and satisfaction with the replacement. RESULTS: Responses were obtained from 109 (77%) THR patients and 129 (72%) TKR patients. Mean age of respondents was 67 yr for THR (47% female) and 73 yr for TKR (60% female). Overall, 85% of patients responded to the WTP question. Of the THR patients, 71% were willing to pay something, 11% were not willing to pay anything and 18% did not answer the question. For TKR patients these figures were 70, 16 and 14% respectively. However, of those who responded to the WTP question, only 25% of the THR patients and 18% of the TKR patients indicated they would be willing to pay the actual current average cost of the operation in Australia (>/= A$15 000). A lower postoperative pain score (as measured by the WOMAC index) was a significant predictor of WTP for both THR and TKR patients. Income also significantly predicted WTP in THR patients but not in TKR patients. The other significant predictors for TKR patients were older age, having private health insurance and willingness to recommend joint replacement to others. CONCLUSIONS: Willingness to pay was a measure that was understandable and acceptable to patients, most of whom were willing to pay something. There was a high correlation between WTP, good health outcomes and patient satisfaction, pain relief being the dominant determinant.

Aged↗