Our unpublished data has indicated that the perivascular stem cells (PSCs) have increased chondrogenic potential compared to mesenchymal stem cells (MSCs) derived in culture.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.
Proximal femoral fractures remain the most common reason for admission to hospital following orthopaedic injury, with an annual cost of £1.7 billion to the National Health Service and social care services. Fragility fractures of the hip in the elderly are a substantial cause of mortality and morbidity. Revision surgery for any cause carries a higher morbidity, mortality, healthcare- and social economic burden. Which patients suffer failed surgery and the reasons for failure have not been established. The aim of this study was to determine which patients are at risk of failed proximal femoral fracture surgery, the mechanism and cause fo failed surgery and modifiable patient factors associated with failure of hip fracture surgery. From prospectively collected data of 795 consecutive proximal femoral fractures admitted between July 2007 and July 2008, all peri-operative and post-operative complications were identified. 55 (6.9%) patients were found to have developed a surgical complication requiring further intervention. Risk factors included younger age (p=0.01), smoking (p=0.01) and cannulated screw fixation (p<0.01). Cannulated screw fixation was associated with a 30.9% complication rate. Mechanical cause was the most common reason for cannulated screw failure. Hip hemiarthroplasty most commonly failed by infective causes. Inter-trochanteric and subtrochanteric fracture fixation had very low failure rates. Surgical complication was not found to be associated with an increased mortality but a post-operative medical complication (21.8%) was associated with higher rate of mortality at 4-years (78.5%) and shorter time to mortality. (Median time 0.16 years (95% CI 0.00–0.33).
Open or closed fracture of the tibial shaft is a common injury. There is no long-term outcome data of patients after tibial shaft fracture utilising modern treatment methods. This study assessed pain and function of 1509 consecutive patients with a tibial shaft fracture at 12–22 years following injury. Secondary outcomes included: effect on employment, effect of social deprivation, necessity for hardware removal and comparative morbidity following fasciotomy. Prospective study of 1509 consecutive adult patients with a tibial shaft fracture (1990–1999) at a high-volume trauma unit. 1034 were male, and the mean age at injury was 40 years. Fractures were classified according to AO, and open fractures graded after Gustillo and Anderson. Time to fracture union, complication rate, hardware removal and incidence of anterior knee pain were recorded. Employment and assessment of social deprivation were detailed. Function was assessed at 12 to 22 years post injury using the Short Musculoskeletal Functional Assessment and Short Form 12 questionnaires. 87% of fractures united without further intervention. Social deprivation was associated with higher incidence of fracture and poorer functional and economic outcomes. 11.5% patients underwent fasciotomy which correlated with poorer long-term outcome. Tibial shaft fracture had high mortality in the elderly. At long-term follow-up 25% of patients have anterior knee pain and 20% ankle discomfort after IM nailing. This is the largest and longest study assessing functional and economic outcomes of tibial shaft fracture. This is the first paper to describe ankle pain following tibial IM nailing at long-term follow-up.
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.
There is limited literature regarding the outcome of hip and knee arthroplasty (THR and TKR) in the Super-Elderly (≥80yrs). The aim is to compare the outcome of THR and TKR in the Super-Elderly with a standard-age cohort of patients. From January 2006 to August 2008; 1290 TKR and 1344 THR were performed at the study institute. Comorbidity, length of stay, patient satisfaction, Oxford knee or hip scores, and SF12 scores were recorded prospectively. The Oxford Score and SF12 were recorded at one year. The mode age range was 65-74yrs for TKR (n=492) and THR (n=495), deemed the standard cohort. 185 TKR and 171 THR were performed in the Super-Elderly. Outcome in this cohort was compared to the standard. The standard cohort had a greater absolute improvement in Oxford knee scores (15.8 and 14.7.p=0.2). Improvement of absolute Oxford hip scores revealed no difference (20.0 and 20.2.p=0.8), but the Super-Elderly had a greater improvement in pain components (11.0 vs.12.0.p=0.05) with a lesser improvement of the functional components (9.0.vs.8.2.p=0.05). There was a greater improvement in the physical component of the SF-12 score in the standard cohort for both TKR and THR (10.6.vs.7.9.p=0.05 and 14.4.vs.10.4.p=<0.01, respectively). No significant difference was seen in comorbidities, but the Super-Elderly patients had a longer hospital stay for TKR (6.2.vs.8.3.p=0.01) and THR (5.9.vs.9.0.p=0.01). The Super-Elderly were more satisfied with their surgery (p=0.05). Super-Elderly patients have comparable outcomes to their younger counterparts and are more satisfied with their surgery, but they may require a longer length of stay.
