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Ian Learmonth

Publications and source records attributed to Ian Learmonth.

6 recordsLinked to original sources
PubMed2007

Three-dimensional cartilage tissue engineering using adult stem cells from osteoarthritis patients.

OBJECTIVE: To determine whether it is possible to engineer 3-dimensional hyaline cartilage using mesenchymal stem cells derived from the bone marrow (BMSCs) of patients with osteoarthritis (OA). METHODS: Expanded BMSCs derived from patients with hip OA were seeded onto polyglycolic acid scaffolds and differentiated using transforming growth factor beta3 in the presence or absence of parathyroid hormone-related protein (PTHrP) to regulate hypertrophy. Micromass pellet cultures were established using the same cells for comparison. At the end of culture, the constructs or pellets were processed for messenger RNA (mRNA) analysis by quantitative real-time reverse transcription-polymerase chain reaction. Matrix proteins were analyzed using specific assays. RESULTS: Cartilage constructs engineered from BMSCs were at least 5 times the weight of equivalent pellet cultures. Histologic, mRNA, and biochemical analyses of the constructs showed extensive synthesis of proteoglycan and type II collagen but only low levels of type I collagen. The protein content was almost identical to that of cartilage engineered from bovine nasal chondrocytes. Analysis of type X collagen mRNA revealed a high level of mRNA in chondrogenic constructs compared with that in undifferentiated BMSCs, indicating an increased risk of hypertrophy in the tissue-engineered cells. However, the inclusion of PTHrP at a dose of 1 microM or 10 microM during the culture period resulted in significant suppression of type X collagen mRNA expression and a significant decrease in alkaline phosphatase activity, without any loss of the cartilage-specific matrix proteins. CONCLUSION: Three-dimensional hyaline cartilage can be engineered using BMSCs from patients with OA. This method could thus be used for the repair of cartilage lesions.

Adult↗
PubMed2006

The effects of surgical volumes and training centre status on outcomes following total joint replacement: analysis of the Hospital Episode Statistics for England.

OBJECTIVE: Previous work from other countries has shown a significant inverse relationship between the number of some surgical procedures undertaken in a hospital and in an adverse outcomes. In the light of the changing nature of the provision of joint replacements in the United Kingdom, we have examined the effects of surgical volumes and the presence/absence of training centre status, on outcomes following total joint replacement (TJR) in England. METHODS: Analysis of the Hospital Episode Statistics (HES) on all hip/knee joint replacements in English National Health Service (NHS) trusts between financial years 1997 and 2002. Exposures explored were the volume of hip/knee replacements per annum in an NHS trust, training centre status and whether the admission was routine or emergency. Four surrogate measures of adverse outcome were assessed: 30-day in-hospital mortality, length of stay in hospital, readmission within a year and surgical revision within 5 years. Age and sex were controlled for as potential confounders. RESULTS: Data from a total of 281 360 hip replacements and 211 099 knee replacements were examined. HES data show that the numbers of TJRs performed in low volume trusts are small and decreasing. Adverse outcomes were also uncommon. Nevertheless, significant associations between adverse outcomes and low volume units, and better outcomes in training centres, were detected. For example, the odds ratio (OR) for in-hospital death within 30 days of hip replacement in trusts doing <50 hip/replacements per annum is 1.98 [95% confidence interval (95% CI) = 1.13-3.47] compared with trusts doing 251-500 operations/annum. Similarly, surgery in non-training centres is more likely to result in mortality than that in training centres (OR = 1.25, 95% CI = 1.05-1.48). The examination of surgical revision indicated adverse outcomes in higher volume units; this may be due to case-mix. CONCLUSION: In England, there are fewer adverse events following TJR in high volume centres and in orthopaedic training centres. Standardization of procedures may account for this finding. The data have implications for private practice in the United Kingdom and for the current move to undertake TJRs in Independent Sector Treatment Centres.

Arthroplasty, Replacement, Hip↗
PubMed2003

Orthopaedic surgery. Joint effort.

Hip replacement surgery is becoming increasingly specialised and evidence shows that, particularly in revision, surgery is best done by specialists. An audit of GPs suggests great variation in referral practice, with one-third prepared to refer to a 'generalist' orthopaedic surgeon. GPs need better communication with hospitals and knowledge of where specialists are available.

Arthroplasty, Replacement, Hip↗
PubMed2003

A comparison of the reliability and validity of bone stock loss classification systems used for revision hip surgery.

Three femoral (Paprosky, American Academy of Orthopaedic Surgeons [AAOS], and Endo-Klinik) and 2 acetabular (Paprosky, AAOS) bone stock loss classification systems were evaluated for reliability. Four observers (2 consultants, 2 registrars) graded the bone loss in 25 patients using preoperative radiographs. Grading was repeated after a minimum of 2 weeks. Interobserver and intraobserver reliability was investigated. The kappa statistic was used to assess levels of agreement. Intraobserver agreement ranged from poor to good. Interobserver agreement ranged from fair to moderate. The validity of the Paprosky classification system was evaluated, comparing preoperative bone stock loss assessment with intraoperative findings. Agreement levels of moderate (femoral classification system) to good (acetabular classification system) were achieved. Bone stock loss classification systems are shown to be inconsistent and unreliable.

Arthroplasty, Replacement, Hip↗