A Case of Multi-focal Osteonecrosis in the Context of Liver Transplant Following Ingestion of Amanita phalloides Mushroom Toxin.

We present the case of a 44-year-old female who presented with atraumatic avascular necrosis (AVN) of the patella and hips bilaterally, following ingestion of the deadly fungus Amanita phalloides or 'death cap' and subsequent liver transplant. Upon presentation, in the hours following ingestion, our patient required a liver transplant and ICU admission. She was treated by a multidisciplinary team, with input from various specialities. Our patient required steroids in the months following this event. Six months after the liver transplant and subsequent ICU admission, our patient developed hip pain, thus limiting her mobility, ability to engage in physiotherapy and rehabilitation. X-rays were performed that excluded any acute pathology. She was still receiving high-dose steroids at this time. When the pain did not resolve with analgesia, MRI of pelvis and knee was performed and the patient was found to have polyarticular AVN. Acute bilateral total hip replacement was performed and within weeks, the patient returned to physiotherapy and to full rehabilitation. Conservative management of the patella was favoured. Over two years later, the patient can now mobilise independently. The role of acute total hip replacement is evident in this case, and how in performing this surgery, the overall conditioning and health of our patient improved drastically. Currently, cases reporting A. phalloides ingestion are few and we wish to use this case to highlight the differential diagnosis in a patient presenting with joint pain in this context of fungus ingestion, organ transplant or prolonged steroid use.

Is Routine Hemoglobin Monitoring Necessary after Elective Hip and Knee Arthroplasty?

BACKGROUND: Many orthopaedic units measure hemoglobin (Hb) levels after primary joint arthroplasty to identify patients with postoperative anemia. With the refinement of surgical techniques, blood loss in primary arthroplasty has decreased. The aim of this study was to investigate the postoperative Hb monitoring and transfusion practices in our own institution after elective hip or knee arthroplasty. METHODS: We conducted a retrospective audit of all patients who underwent elective total hip or knee arthroplasty in Galway University Hospital between March 1 and June 1, 2019. We recorded when they underwent postoperative Hb testing, whether or not they had a drop of Hb, which would indicate transfusion (<8 g/dL), and whether or not they were transfused. In patients who underwent transfusion, a chart review was performed to establish the presence of factors that would have triggered repeat Hb testing. RESULTS: One hundred thirty-six patients underwent elective primary hip or knee arthroplasty in the period. All had a full blood count sent on the first postoperative day. None (0%) had a clinically significant (to < 8g/dL) postoperative Hb drop on day 1. Eighteen (13.2%) patients underwent repeat testing on day 2 or subsequently. Eight (5.9%) exhibited a drop in Hb to less than 8 g/dL, with a mean Hb drop of 4.26 (standard error of the mean ± 0.862, standard deviation ± 0.98), and 5 (3.7%) proceeded to undergo allogenic blood product transfusion. All 5 underwent documented indications for repeat Hb testing. CONCLUSIONS: There is no evidence for performing routine Hb testing on day 1 after elective hip or knee arthroplasty. We recommend that postoperative Hb testing should only be carried out on patients with additional indications.

The long-term outcomes following internal fixation for intracapsular hip fractures in an Irish tertiary referral centre.

BACKGROUND: The burden associated with hip fractures is increasing worldwide. Arthroplasty procedures are more commonly performed for intracapsular fractures due to increased risk of compromise to the femoral head blood supply. However, we know from the Irish Hip Fracture Database that a significant proportion of these fractures undergo internal fixation. AIMS: We sought to investigate the long-term outcomes for these patients including revision rates, functional outcome and mortality rates. METHODS: All intracapsular fractures treated by internal fixation (IF) from 2005 to 2009 were identified. Pre-operative anatomical fracture location and level of fracture displacement was established. Hospital records were used to record mortality and revision rates. The modified Harris hip score was our primary functional outcome measure. RESULT: One hundred twelve intracapsular fractures underwent IF over a 5-year period. The mean age was 68.6 (range 14-95 years). A mean follow-up time of 8.15 years (range 6.7-10.1 years) was achieved. There was a 5-year mortality rate of 36.6%. There was a significantly higher revision rate in displaced fractures (24.4%) than in undisplaced fractures (11.1%) (p = 0.01). We found no difference in functional outcome between displaced fractures [85.9 (± 16.9)] and undisplaced fractures [86.01 (± 18.8)]. Those aged younger than 65 at the time of surgery had a significantly better MHHS (p = 0.02) at long-term follow-up; however, there was a revision rate of 43.8% in this group. CONCLUSION: Whilst a good functional outcome can be achieved with internal fixation, particularly in younger patients, the risk of requiring revision surgery approaches 50% for these patients.

Combinatorial gene therapy accelerates bone regeneration: non-viral dual delivery of VEGF and BMP2 in a collagen-nanohydroxyapatite scaffold.

Vascularization and bone repair are accelerated by a series of gene-activated scaffolds delivering both an angiogenic and an osteogenic gene. Stem cell-mediated osteogenesis in vitro, in addition to increased vascularization and bone repair by host cells in vivo, is enhanced using all systems while the use of the nanohydroxyapatite vector to deliver both genes markedly enhances bone healing.

High levels of ephrinB2 over-expression increases the osteogenic differentiation of human mesenchymal stem cells and promotes enhanced cell mediated mineralisation in a polyethyleneimine-ephrinB2 gene-activated matrix.

Gene therapy can be combined with tissue engineering constructs to produce gene-activated matrices (GAMs) with enhanced capacity for repair. Polyethyleneimine (PEI), a non-viral vector, has previously been optimised for high efficiency gene transfer in rat mesenchymal stem cells (rMSCs). The use of PEI to transfect human MSCs (hMSCs) with ephrinB2 is assessed here. Recently a role for the ephrinB2 ligand and EphB4 receptor duo has been proposed in bone remodelling. Herein, over-expression of the ephrinB2 ligand resulted in increased osteogenic differentiation in hMSCs. As ephrinB2 is a cell surface anchored ligand which only interacts with cells expressing the cognate EphB4 receptor through direct contact, we have shown that direct cell-cell contact between two neighbouring cells is responsible for enhanced osteogenesis. In an effort to begin to elucidate the molecular mechanisms at play downstream of ephrinB2 over-expression, RT-PCR was performed on the GAMs which revealed no significant changes in runx2 or BMP2 expression but an upregulation of osterix (Osx) and Dlx5 expression prompting the belief that the mode of osteogenesis is independent of the BMP2 pathway. This select interaction, coupled with the transient gene expression profile of PEI, makes the PEI-ephrinB2 GAM an ideal candidate matrix for a bone targeted GAM.