Tranexamic acid (TXA) is an anti-fibrinolytic medication commonly used to reduce peri-operative bleeding. Increasingly, topical administration as an intra-articular injection or peri-operative wash is being administered at concentrations between 10–100mg/ml. This study investigated effects of TXA on human periarticular tissues and primary cell cultures using clinically relevant concentrations. Tendon, synovium and cartilage obtained from routine orthopaedic surgeries were used ex vivo or cultured for in vitro studies using various concentrations of TXA. They were stained with 5-chloromethylfluorescein diacetate and propidium iodide and imaged using confocal microscopy to identify the proportion of live and dead cells. The in vitro effect of TXA on primary cultured tenocytes, synovial like fibroblast (FLS) cells and chondrocytes was investigated using cell viability assays (MTT), fluorescent microscopy and multi-protein apoptotic arrays for cell death. There was significant (p<0.01) increase in cell death in all tissue treated with 100mg/ml TXA, ex vivo. MTT assays revealed significant (p<0.05) decrease in cell viability following treatment with 50 or 100mg/ml of TXA within 4 hours of all cell types cultured in vitro. Additionally, there was significant (p<0.05) increase in cell apoptosis detected by fluorescent microscopy within 1 hour of exposure to TXA. Furthermore, multi-protein apoptotic arrays detected increased apoptotic proteins within 1 hour of TXA treatment in tenocytes and FLS cells. Our study provides evidence of TXA cytotoxicity to human peri-articular tissues ex vivo and in vitro at concentrations and durations of treatment routinely used in clinical environments. Clinicians should therefore show caution when considering use of topical TXA administration.
A tip-apex distance (TAD) greater than 25 mm is a strong predictor of screw cut-out in patients with intertrochanteric femoral fracture treated with a dynamic hip screw (DHS). We aim to show you a simple and reliable way to check this. By calculating the sum of the distance from the tip of the screw to the apex of the femoral head on anteroposterior and lateral views the TAD is found. X-rays often have magnification errors and therefore measuring tools in digital x-ray systems will be inaccurate. The original method of calculating the TAD uses the known diameter of the screw to avoid magnification errors. We found that due to the no-cylindrical shape of the screw shaft there is potential of an inaccurate measurement. By using the distance across the highest points of the thread a more accurate TAD can be calculated. The distance across the highest points of the threads in all three of the most commonly used DHSs in the UK is 13 mm. If the measured distance from the tip of the screw to the apex of the femoral head in both the anteroposterior and lateral views is less than the measured distance across of the treaded diameter of the screw then the surgeon knows the TAD is less than 26 mm. This method can be used intraoperatively to check the TAD by looking at the fluoroscopy images in these two views.
Femoroacetabular impingement (FAI) is a significant cause of osteoarthritis in young active individuals but the pathophysiology remains unclear. Increasing mechanistic studies point toward an inflammatory component in OA. This study aimed to characterise inflammatory cell subtypes in FAI by exploring the phenotype and quantification of inflammatory cells in FAI versus OA samples. Ten samples of labrum were obtained from patients with FAI (confirmed pathology) during open osteochondroplasty or hip arthroscopy. Control samples of labrum were collected from five patients with osteoarthritis undergoing total hip arthroplasty. Labral biopsies were evaluated immunohistochemically by quantifying the presence of macrophages (CD68 and CD202), T cells (CD3), mast cells (mast cell tryptase) and vascular endothelium (CD34). Labral biopsies obtained from patients with FAI exhibited significantly greater macrophage, mast cell and vascular endothelium expression compared to control samples. The most significant difference was noted in macrophage expression (p<0.01). Further sub typing of macrophages in FAI using CD202 tissue marker revealed and M2 phenotype suggesting that these cells are involved in a regenerate versus a degenerate process. There was a modest but significant correlation between mast cells and CD34 expression (r=0.4, p<0.05) in FAI samples. We provide evidence for an inflammatory cell infiltrate in femoroacetabular impingement. In particular, we demonstrate significant infiltration of mast cells and macrophages suggesting a role for innate immune pathways in the events that mediate hip impingement. Further mechanistic studies to evaluate the net contribution and hence therapeutic utility of these cellular lineages and their downstream processes may reveal novel therapeutic approaches to the management of early hip impingement.
Posterior soft tissue repair is often performed in Total Hip Arthroplasty (THA). Many reports have shown the advantage of posterior soft tissue repair in reducing their prosthetic hip dislocation rates. We describe an easy and inexpensive way of passing sutures through small drill holes in the Greater Trocanter to re-attach muscle, tendon and capsule in a posterior soft tissue repair. By using a reversed monofilament suture on a straight needle held in artery forceps and passing this in a retrograde direction through a drill hole, a suture capturing device is produced. By capturing the long ends of sutures tied in the short external rotators and the posterior capsule of the hip through 2 drill holes in the Greater Trochanter, a posterior soft tissue repair can be performed. We have used this technique successfully in over 100 consecutive THAs. We conclude that the use of a monofilament suture used in the manner describe is an excellent and inexpensive way to aid in a posterior soft tissue repair in THAs. This is done without the cost of an additional dedicated suture passing device. The suture could also be used in the skin closure if desired.
Femoroacetabular impingement (FAI) is a significant cause of osteoarthritis in young active individuals but the pathophysiology remains unclear. Increasing mechanistic studies point toward an inflammatory component in OA. This study aimed to characterise inflammatory cell subtypes in FAI by exploring the phenotype and quantification of inflammatory cells in FAI versus OA samples. Ten samples of labrum were obtained from patients with FAI (confirmed pathology) during open osteochondroplasty or hip arthroscopy. Control samples of labrum were collected from five patients with osteoarthritis undergoing total hip arthroplasty. Labral biopsies were evaluated immunohistochemically by quantifying the presence of macrophages (CD68 and CD202), T cells (CD3), mast cells (mast cell tryptase) and vascular endothelium (CD34). Labral biopsies obtained from patients with FAI exhibited significantly greater macrophage, mast cell and vascular endothelium expression compared to control samples. The most significant difference was noted in macrophage expression (p<0.01). Further sub typing of macrophages in FAI using CD202 tissue marker revealed and M2 phenotype suggesting that these cells are involved in a regenerate versus a degenerate process. There was a modest but significant correlation between mast cells and CD34 expression (r=0.4, p<0.05) in FAI samples. We provide evidence for an inflammatory cell infiltrate in femoroacetabular impingement. In particular, we demonstrate significant infiltration of mast cells and macrophages suggesting a role for innate immune pathways in the events that mediate hip impingement. Further mechanistic studies to evaluate the net contribution and hence therapeutic utility of these cellular lineages and their downstream processes may reveal novel therapeutic approaches to the management of early hip impingement.
FAI has been implicated in the progression of osteoarthritis (OA) and early detection may allow for treatment, which can slow or halt progression. FAI is a difficult condition to image and there is little objective evidence about imaging accuracy. We aim to measure the accuracy of five imaging modalities. Three blinded observers retrospectively reviewed five different modalities from two age and sex matched groups: A patient group referred to the outpatient clinic with a clinical diagnosis of FAI and a control group who had had CT scans of the pelvis for suspected trauma, where the Pelvic scan had been reported as showing no injuries. The imaging modalities were: Standard x-ray; Antero-Posterior, Lateral; Condition-specific x-ray projections; Dunn view, lateral internal rotation; Standard Computer Tomography (CT) multiplanar reconstruction (MPR); axial, sagittal and coronal; Condition-specific CT MPR; angled axial, angled coronal; 3D modelling; and surface rendered dynamic. We found marked variations in the sensitivity, specificity, Positive Predictive Value (PPV) and Negative Predictiive Value (NPV) for each of the following imaging modalities: Standard X-ray; Sensitivity 51.9; Specificity; 57.1; PPV; 40; NPV; 68.3 Special X-rays; Sensitivity; 66.7; Specificity; 57.1; PPV; 46.1; NPV; 75.7. Standard CT MPR; Sensitivity; 40.7; Specificity; 75.5; PPV; 47.8; NPV; 69.8 Special CT MPR; Sensitivity; 48.1; Specificity; 57.1; PPV; 46.4; NPV; 70.8 Dynamic 3D CT models; Sensitivity; 55.6; Specificity; 69.3; PPV; 42.8; and NPV; 71.8. The Dynamic 3D CT models (where the observer can manipulate the model in real time three dimension to control the perspective) proved to be the most accurate, closely followed by the special X-Ray views, which were also the most sensitive. The Standard CT MPRs were the most specific but had a low sensitivity. This is the first study to measure sensitivity, specificity and PPV and NPV for these imaging modalities in FAI. We recommend the use of condition-specific X-Ray views as well as 3D CT Models for optimal imaging accuracy in this condition. Standard X-Ray views and CTs proved less useful.
Accurate implant alignment, prolonged operative times, array pin site infection and intra-operative fracture risk with computer assisted knee arthroplasty is well documented. This study compares the accuracy and cost-effectiveness of the pre- operative MRI based Signature custom made guides (Biomet) to intra-operative computer navigation (BrainLab Knee Unlimited). Twenty patients from a single surgeon's orthopaedic waiting list awaiting primary knee arthroplasty were identified. Patients were contacted and consented for the study and their suitability for MRI examination assessed. An MRI scan of the hip, knee and ankle was performed of the operative side following a set scanning protocol. Following MRI, patient specific femoral and tibial positioning cutting guides were manufactured. Patients then underwent arthroplasty and intra-operative computer navigation was used to measure the accuracy of the custom made, patient specific cutting guides. A cost analysis of the signature system compared with computer navigation was made. Our provisional results show that the accuracy of the pre-operative MRI patient specific femoral and tibial positioning guides was comparable to computer navigation. Pre-operative, patient specific implant positioning cutting guides were as accurate as computer navigation from analysis of our preliminary results. The potential advantages of the MRI based system are accurate pre-operative planning, reduced operating times and avoidance of pin site sepsis. However, further larger studies are required to examine this technique.
Open reduction and internal fixation of acetabular fractures demands detailed preoperative planning, and given their frequent complexity, a thorough understanding of their three-dimensional (3D) form is necessary. This study aims to assess if the use of dynamic 3D models will improve preoperative planning of acetabular fractures. In this study, three experienced pelvic trauma surgeons were provided with computer based dynamic 3D models in addition to preoperative radiographs, CT scans and static 3D reconstructions of 17 acetabular fractures operatively managed at the Royal Melbourne Hospital. Surgeons, blinded to any previous operative plan or patient detail, then classified fracture type and made preoperative surgical plans. Comparison was then made to classification and operative approach documented in the patient's operation notes. Comparison was then made with regard to surgical plan and planning time with or without access to dynamic 3D models. In complex cases the additional information provided by dynamic 3D modelling was found to reduce planning time and, in some cases, change the surgical plan. For complex acetabular fractures we recommend that surgeons should have access to computer-based dynamic 3D models of the injuries for pre-operative planning.
With the advent of digital radiology, our institution has introduced digital templating for preoperative planning of total hip arthroplasty (THA). Prior studies of the accuracy of digital templating had contradictory results. This study compares the accuracy of digital and analog templating for THA. Ninety patients were recruited. Sixty-eight patients had analog pre-operative templating while 22 patients had digital templating. A retrospective review of medical records obtained the sizes of hip implants inserted during THA and patient demographics. The templated hip sizes were compared with the actual hip implants inserted. Accuracies of both templating methods were compared in four outcomes: prediction of acetabular cup size, prediction of femoral stem size, prediction of femoral offset and prediction of femoral neck length. Digital templating was more accurate than analog templating in predicting acetabular cup size, femoral stem size and femoral offset. Analog templating was more accurate in predicting femoral neck length. However, only the comparison of femoral offset achieved statistical significance (p-value = 0.049). After stratifying the data by BMI, digital templating was more accurate than analog templating in predicting acetabular cup and femoral stem sizes for patients with high BMI. For patients with BMI = 25-30, accuracy of digital templating was 100.0% for cup and 80.0% for stem while accuracy of analog templating was 74.1% for cup and 74.1% for stem. For patients with BMI > 30, accuracy of digital templating was 84.6% for cup and 69.2% for stem while that of analog templating was 75.0% for cup and 66.7% for stem. Digital templating outperformed analog templating in all the outcomes except femoral neck length. In addition, digital templating was significantly more accurate in predicting femoral offset. This study showed that digital templating has the potential to reduce errors in pre-operative planning for THA.
Detailed preoperative planning is essential for open reduction and internal fixation of acetabular fractures if a successful outcome is to be achieved. Decisions such as patient positioning, approach, reduction techniques and implant positioning are greatly influenced by fracture pattern and displacement. These fractures are frequently complex and a thorough understanding of their 3-Dimensional (3D) form is necessary for pre-operative decision making. A combination of biplanar x-rays, 2 Dimensional CT scans (Axial, Sagittal and Coronal multi-plane reformats) and, more recently, 3D CT reconstructions are provided routinely. However, the 3D reconstructions are provided to surgeons as static 2D pictures of the 3D model (up to 6 different views), rather than a true 3D representation. In this study we used dynamic 3D models to provide additional information to surgeons. The 3D models were generated on a standard desktop or laptop computer and can be used in the operating theatre (Osirix Dicom viewing software). These true 3D reconstructions allow the surgeon to manipulate the model himself in real time so that the fracture can be viewed at any angle and overlying fragments removed to expose deeper structures. 3 experienced consultant pelvic trauma surgeons reviewed plain radiographs and 2D Pelvic CT scans from 20 acetabular fractures. They were asked to make a preoperative plan with regard to fracture classification and planned surgical approach(s). At separate, time-spaced, sittings they were provided with a 3D Static and 3D Dynamic CT reconstruction in addition. They were blinded to any previous plan and the patients’ details. A comparison was then made with regard to surgical plan and the time taken to make that plan with or without access to dynamic 3D models. The additional information provided by dynamic 3D modelling was found to reduce planning time and, in some cases, change the surgical plan.
The aim of this work was to compare the oxygen saturations in patients in the early period following total knee joint replacement surgery performed using either computer navigation or conventional intramedullary mechanical jigs. Between August and November 2007 twelve consecutive patients who had computer navigated total knee joint replacements were prospectively reviewed. A comparison group from the same period was made of twenty patients who had knee replacements performed with conventional jigs in this same period. Non-invasive oxygen saturations were measured and recorded as a percentage. Preoperative oxygen saturations measured at the assessment clinic were used a baseline. For the duration of the patients postoperative hospital stay oxygen saturations were measured five times a day as well as their oxygen requirements. We found that the patients in the computer navigation group on average reached oxygen saturation levels on air equal to those measured in the assessment earlier than the intramedullary jig group (2.2 days versus 2.8 days). There was also a lower need for oxygen and shorter length of stay in the computer navigated group during this early post operative period (4.6 versus 6.0 days). Previous studies using transcranial Doppler and transoesophageal echocardiograms have shown a reduction of systemic emboli with computer navigated total knee joint replacements. Using oxygen saturation monitoring we have shown there may be a considerable clinical advantage using computer navigated surgery over conventional intramedullary jigs in knee replacement surgery.
The aim of this work was to compare the oxygen saturations in patients in the early period following total knee joint replacement surgery performed using either computer navigation or conventional intramedullary mechanical jigs. Between August and November 2007 twelve consecutive patients who had computer navigated total knee joint replacements were prospectively reviewed. A comparison group from the same period was made of twenty patients who had knee replacements performed using conventional jigs. Non-invasive oxygen saturations were measured and recorded as a percentage. Preoperative oxygen saturations measured at the assessment clinic were used a baseline. For the duration of the patients postoperative hospital stay oxygen saturations were measured five times a day as well as their oxygen requirements. We found that the patients in the computer navigation group on average reached oxygen saturation levels on air equal to those measured in the assessment earlier than the intramedullary jig group. There was also a lower need for oxygen in the computer navigated group during this early post operative period. Previous studies using transcranial Doppler and transoesophageal echocardiograms have shown a reduction of systemic emboli with computer navigated total knee joint replacements. Using oxygen saturation monitoring we have shown there may be a considerable clinical advantage using computer navigated surgery over conventional intra-medullary rod jigs in knee replacement surgery.
Inaccurate positioning of components results in suboptimal knee function, implant wear and early loosening of the prosthesis. Small differences in varus/valgus angulation have been shown not to affect outcome, but, when the prosthesis is more than 3 degrees malaligned from neutral, premature failure rates rise. Accurate alignment requires proper orientation in the placement of the cutting guides and computer-aided navigation systems have now been developed with the aim of improving this. We compared the post-operative leg alignment following computer assisted (Orthopilot) versus conventional (IB2 with extramedullary tibial and intramedullary femoral jigs) methods of TKJR using weight-bearing long leg radiographs. This was a study of 91 consecutive TKJRs (51 IB2s and 40 Orthopilot Search Evolution knees) performed in 70 patients. A single experienced knee surgeon carried out all these procedures. All these patients had weight-bearing long leg alignment films taken by a single experienced radiographer. The anatomical centres of ankle, knee and hip were then marked on each film and the tibia femoral angles drawn. Two separate blinded observers then measured the angles of malalignment. Observer A’s results show that 95% of the Orthopilot knees were within 3 degrees of varus or valgus from neutral. Only 74.47% of the IB2 group were within this range (p=0.011). For Observer B 87.5% of Orthopilot knees and 70.21% of IB2s were within the range (p=0.052). When we group these finding we see that an average of 91.25% of the Orthopilot and 72.34% of the IB2 knees are within the range (p=0.025). When the interobserver figures for each group were compared no significant difference was found.
In 91 consecutive TKJRs, the first 50 were performed by conventional methods and a computer navigation system was used for the last 41 in the series. All were performed by the same experienced knee surgeon. The tibiofemoral degree of malalignment was measured in each long leg film, using the centre of the hip, knee and ankle joints as reference points. Two observers performed each measurement blind and at a single sitting. The same experienced radiographer took all the x-rays in a standardised manner using a kodek long leg film and cassette.
