Aims

It is imperative to understand the risks of operating on urgent cases during the COVID-19 (SARS-Cov-2 virus) pandemic for clinical decision-making and medical resource planning. The primary aim was to determine the mortality risk and associated variables when operating on urgent cases during the COVID-19 pandemic. The secondary objective was to assess differences in the outcome of patients treated between sites treating COVID-19 and a separate surgical site.

The fingers and thumb are the second most common site for dislocation of joints following injury (3.9/10,000/year). Unlike fractures, the pattern and patient reported outcomes following dislocations of the hand have not previously been reported.

All patients presenting with a dislocation or subluxation of the fingers or thumb were included in this cohort study (November 2008 and October 2009). Patient demographic and injury data were obtained and dislocation pattern confirmed on radiographs. Patient reported outcomes were obtained using the Michigan Hand Outcome Questionnaire (MHQ).

There were 202 dislocations/subluxations recorded. MHQ scores were obtained at 3–5 years for 74percnt; patients. The average age at injury was 40 years, 76percnt; (146) patients were male and 11percnt; (23) injuries were open. 50percnt; (101) of the dislocations were dorsal, 28percnt; (57) were associated with fractures and 4percnt; (9) were recurrent.

There were significant associations between: 1, Direction of dislocation and finger involved (p=0.03); 2, Joint and mechanism of dislocation (p=0.001); 3, Mechanism and direction of dislocation (p=0.008). Older patients had significantly worse outcomes (p<0.001).

This is the first study to assess the epidemiology and patient reported outcomes following dislocation of the fingers and thumb allowing us to better understand these injuries.

Our unpublished data has indicated that the perivascular stem cells (PSCs) have increased chondrogenic potential compared to mesenchymal stem cells (MSCs) derived in culture. There has been a recent change in the theory that stem cells work by a paracrine effect rather than differentiation. There are minimal data demonstrating the persistence of implanted stem cells when used for engraftment. This study aimed to develop an autologous large animal model for perivascular stem cells as well as to determine if cells were retained in the articular cartilage defects.

The reactivity of anti-human and anti-ovine antibodies was ascertained using immunohistochemistry and fluorescence-activated cell sorting (FACS). A panel of antibodies were combined and used to identify and purify pericytes (CD34-CD45-CD146+) and adventitial cells (CD34+CD45-CD146-) using FACS. The purified cells were cultured and their identity checked using FACS. These cultured cells demonstrated osteogenic, adipogenic and chondrogenic potential.

Autologous ovine PSCs (oPSCs) were isolated, cultured and transfected using a GFP virus. The transfection rate was 88%. The cells were implanted into an articular cartilage defect on the medial femoral condyle using a hydrogel, four weeks following implantation the condyle was explanted and confocal laser scanning microscopy demonstrated the presence of oPSCs in the defect. Histology did not demonstrate any repair tissue at this early time point.

These data have confirmed the viability our large animal model and that the implanted stem cells were retained in the defect four weeks following implantation.

Perivascular stem cells (PSCs) from lipoaspirate demonstrate increased purity and immaturity with greater engraftment potential than standard mesenchymal stem cells (MSCs). MSCs from the infra-patellar fat pad (IFP) have previously demonstrated increased chondrogenic potential. This study investigated the availability and potential of PSCs harvested from the infra-patellar fat pad of the human knee for musculoskeletal regeneration.

Tissue sections of IFP were stained with markers for PSCs, MSCs and endothelial cells to confirm their presence and location. Samples were obtained from patients undergoing TKR (n=13) or ACL reconstructions (n=10). Pericytes and adventitial cells made up 3.8% and 21.2% respectively of the stromal vascular fraction. The total number of pericytes and adventitial cells were 4.6±2.2×104 and 16.2±3.2×104 respectively. Cells were cultured both separately and combined. Cell identity was ascertained using fluorescence-activated cell sorting, immunocytochemistry and PCR. Cultured PSCs were differentiated using chondrogneic, osteogenic, adipogenic and myogenic medias. Differentiation was determined using Alcian Blue, Alizarin red, Oil Red O and myosin staining.

This study demonstrates that the IPFP is a viable source of PSCs that can be harvested either arthroscopically or through an arthrotomy by orthopaedic surgeons for cell-based musculoskeletal regeneration. Their potential now needs to be compared to conventional MSCs.

Perivascular stem cells (PSCs) from lipoaspirate demonstrate increased purity and immaturity with greater engraftment potential than standard mesenchymal stem cells (MSCs). MSCs from the infra-patellar fat pad (IFP) have previously demonstrated increased chondrogenic potential. This study investigated the availability and potential of PSCs harvested from the infra-patellar fat pad of the human knee for musculoskeletal regeneration.

Sections of IFP were stained with markers for PSCs, MSCs and endothelial cells to confirm their presence and location. Samples were obtained from patients undergoing TKR (n=13) or ACL reconstructions (n=10). Pericytes and adventitial cells made up 3.8% and 21.2% respectively of the stromal vascular fraction. The total number of pericytes and adventitial cells were 4.6±2.2×10⁴ and 16.2±3.2×10⁴ respectively. Cells were cultured both separately and combined. Cell identity was ascertained using fluorescence-activated cell sorting and immunocytochemistry. Cultured PSCs were differentiated using chondrogneic, osteogenic, adipogenic and myogenic medias. Differentiation was determined using Alcian Blue, Alizarin red, Oil Red O and mysosin staining.

This study demonstrates that the IFP is a viable source of PSCs that can be harvested either arthroscopically or through an arthrotomy by orthopaedic surgeons for cell-based musculoskeletal regeneration. Their potential now needs to be compared to conventional MSCs.

Medical employment standards (MES) are used to identify and quantify the effects of pathology on a person's ability to carry out their duties. Any person requiring a change in their MES for longer than 28 days should have their permanent MES altered accordingly. In the Royal Air Force this is undertaken by Medical Boards.

A retrospective review was performed of all personnel attending RAF Medical Boards for a change in their PMES between 15/1/12 and 31/10/13. The primary reason for downgrade was recorded using ICD-10 code.

There were 1,583 PMES downgrades, approximately 800/year. This is approximately 2% of all regular RAF personnel. Musculoskeletal disease accounted for 58% of all cases (923 cases, 500/year). Other causes included medicine and general surgery (23%), mental health (10%), obstetrics and gynaecology (5%) and other causes (4%). The majority of the musculoskeletal cases were arthropathy (42%) or back pain (31%).

Musculoskeletal disease is the most common cause for medical downgrade in the RAF. More data are required to ascertain the precise nature of these cases and the level of the imposed limitations. This will allow targeted use of increasingly limited resources to ensure that our personnel are as fit as possible to execute their duties.

This study investigated confocal laser scanning microscopy (CLSM) as a novel method of imaging of chondrocytes on a collagen membrane used for articular cartilage repair. Cell viability and the effects of surgery on the cells were assessed.

Cell images were acquired under four conditions: 1, Pre-operative 2, After handling 3, Heavily grasped with forceps 4, Cut around the edge. Live and dead cell stains were used. Images were obtained for cell counting and morphology. Mean cell density was 1.12–1.68 ± 0.22 × 10⁶ cells/cm² in specimens without significant trauma (n=25 images), this decreased to 0.253 × 10⁶ cells/cm² in the specimens that had been grasped with forceps (p <0.001) (5 images). Cell viability on delivery grade membrane was 86.8±2.1%. The viability dropped to 76.3 ± 1.6% after handling and 35.1 ± 1.7% after crushing with forceps. Where the membrane was cut with scissors, there was a band of cell death where the viability dropped to 17.3 ± 2.0% compared to 73.4 ± 1.9% in the adjacent area (p <0.001). Higher magnification revealed cells did not have the rounded appearance of chondrocytes.

CLSM can quantify and image the fine morphology of cells on a MACI membrane. Careful handling of the membrane is essential to minimise chondrocyte death during surgery.

It is widely accepted by orthopaedic surgeons that antibiotics should be withheld until aspiration has been performed to increase the odds of identifying an organism in septic arthritis. Patients often present to other specialties that may not be as familiar with these principles.

Twenty-five of forty-nine patients with septic arthritis of the native or prosthetic knee had received antibiotics prior to review by the orthopaedic service. Patients were significantly less likely to demonstrate an organism on initial microscopy (entire cohort p=0.001, native knees p=0.006, prosthetic knees p=0.033) or on subsequent culture (entire cohort p=0.001, native knees p=0.017, prosthetic knees p=0.012) of their aspirate if they had received antibiotics. The sensitivity of microscopy dropped from 0.58 to 0.12 when patients had received antibiotics (native knees 0.46 to 0, prosthetic knees 0.72 to 0.27). The sensitivity of the culture dropped from 0.79 to 0.28 when the patient had received antibiotics (native knees 0.69 to 0.21, prosthetic knees 0.91 to 0.36).

Patients treated with empirical antibiotics are less likely to demonstrate an organism on microscopy and culture of their initial aspirate. There is a significantly high false negative rate associated with knee aspiration, particularly with prior administration of antibiotics.

Aim

Analysis of the effect of administration of antibiotics before collection of microbiology samples in patients with septic arthritis of the native and prosthetic knee.