Introduction and Objective. Digital infra-red thermography may have the capability of identifying local inflammations. Nevertheless, the role of thermography in diagnosing pin site infection has not been explored yet and the reliability and validity of this method for pin site surveillance is in question. The purpose of this study was to explore the capability and intra-rater reliability of thermography in detecting pin site infection. Materials and Methods. This explorative proof of concept study follows GRRAS -guidelines for reporting reliability and agreement studies. After clinical assessment of pin sites by one examiner using Modified Gordon Pin Infection Classification (Grade 0 – 6), thermographic images of the pin sites were captured with a FLIR C3 camera and analyzed by the FLIR tools software package. The maximum skin temperature around the pin site and the maximum temperature for the whole thermographic picture was measured. Intra-rater agreement was established and test-retests were performed with different camera angles. Results. Thirteen (4 females) patients (age 9–72 years) were included. Indications for frames: 4 fracture, 2 deformity correction, 1 lengthening, 6 bone transport. Days from surgery to thermography ranged from 27 to 385 days. Overall, 231 pin sites were included. Eleven pin sites were diagnosed with early signs of infection: five grade 1, five grade 2, one grade 3. Mean pin site temperature was 33.9 °C (29.0–35.4). With 34 °C as cut-off value for infection, sensitivity was 73%, specificity 67%, positive predictive value 10% and negative predictive value 98%. Intra-rater reliability for thermography was ICC 0.85 (0.77–0.92). The temperature measured was influenced by the camera postioning in relation to pin site with a variance of 0.2. Conclusions. Measurements of pin sites using the handheld FLIR C3 infrared camera was a reliable method and the temperature was related to infection grading. This study demonstrates that digital thermography with a handheld camera might be used for monitoring the pin sites after operations to detect early infection, however, future larger prospective studies are necessary

Whereas thermography has already been used as an assessment of disease activity in some kinds of inflammatory arthritis, it is a new method for objektive pain evaluation in patients with joint prosthesis. To our knowledge, no study has tested the correlation between increase of temperature and anterior knee pain with total knee prosthesis yet. Thirteen patients were included in this study who suffered from anterior knee pain of the retinaculum patellae with total knee prosthesis. The patients were asked to walk 3 km before entering a room which was cooled down to 20 degrees Celsius. A black 1 cm times 4.5 cm square stripe was attached on the diameter of the patella and the patients rested for 20 minutes to cool down before thermographic fotos were taken from 90 degrees, 45 degrees, frontal medial and lateral. The evaluation of temperature difference of each side was performed by marking a 1cm times 2cm square field rectangular around the black stripe and comparing it with a reference point of the same size 3 cm distal of the field. The patients were compared with thirteen others, not suffering from anterior knee pain. Statistical analysis was performed using a t- test and a p value < 0.05 was considered to be significant. The temperature differences between the rectangular field and the reference point increased significantly on the medial (p= 0.00037) or lateral (p= 0.000002) pain side of the knee. The thirteen knees with knee pain had significantly higher temperature differences between medial and lateral temperature differences, than the knees without knee pain. We demonstrate a significant correlation between anterior knee pain and an increase of superficial skin temperature around the retinaculum patellae. To our knowledge, this is the first report of an objective assessment of pain of the retinaculum patellae with total knee prosthesis

Thermal osteonecrosis is a side effect when used Kirschner (K) wires and drills in orthopaedic surgeries. This osteonecrosis may endanger the fixation. Orthopaedic surgeons sometimes have to use unsharpened K-wires in emergent surgery. The thermal effect of used and unsharpened K wire is ambiguous to the bone. This experimental study aims to assess the thermal osteonecrosis while drilling bone with three different types of K-wires especially a previously used unsharpened wire and its thermographic measurements correlation. Two different speeds of rotation were chosen to investigate the effect of speed on thermal necrosis to the bone.

A total of 16 New Zealand white rabbits weighing a mean of 2.90 kg (2.70 – 3.30 kg) were used. All rabbits were operated under general anaesthesia in a sterile operating room. Firstly, 4 cm longitudinal lateral approach was used to the right femur and then the femur was drilled with 1.0 mm trochar tip, spade tip and previously used unsharpened K-wires and 1.0 mm drill bit at 1450 rpm speed. Left femur was drilled with same three type K-wires and drill bit at 330 rpm speed. One cm distance was left among four penetrations on the femur. The thermal changes were recorded by Flir® E6 Thermal Camera from 50 cm distance and 30-degree angle. Thermographic measurements saved for every drilling process and recorded for the highest temperature (°C) during the drilling. All subjects were sacrificed post-operatively on the eighth day and specimens were prepared for the histological examination. The results of osteonecrosis assessment score and thermographic correlation were evaluated statistically.

Histological specimens were evaluated by the scoring of osteonecrosis, osteoblastic activity, haemorrhage, microfracture and inflammation. Results were graded semi-quantitatively as none, moderate or severe for osteonecrosis, haemorrhage and inflammation. The microfracture and osteoblastic activity were evaluated as present or absent. There was no meaningful correlation between osteonecrosis and the drilling speed (p=0.108). There was less microfracture zone which was drilled with trochar tip K-wires at 1450 rpm speed (p=0.017). And the drilling temperature of trochar tip K-wires was higher than the others(p=0.001). Despite this evaluation, osteonecrosis zone of spade and unsharpened tip K-wires were more than trochar tip K-wires (p=0.039). The drill bit at 330 rpm caused the least osteonecrosis and haemorrhage and respectfully the lowest drilling temperature (p=0,001). The osteoblastic activity shows no difference between the groups. (p=0,122; 0,636;0.289)

On the contrary to the literature, our experiment showed that there is no meaningful correlation between osteonecrosis score and temperature produced by drilling. The histological assessment showed the osteonecrosis during short drilling time but, not clarify the relation with drilling temperature. Eventually, the osteonecrosis showed a positive correlation with drilling time independently of drilling temperature at 330 rpm. (p=0,042) These results show that we need more studies to understand about osteonecrosis and its relationship with drilling heat temperature. Trochar tip K-wires creates higher drilling temperature but less osteonecrosis than a spade and unsharpened cut tip K-wires. Using unsharpened tip K-wire causes more osteonecrosis. Previously used and, unsharpened K-wires should be discarded

To detect early signs of infection infrared thermography has been suggested to provide quantitative information. Our vision is to invent a pin site infection thermographic surveillance tool for patients at home. A preliminary step to this goal is the aim of this study, to automate the process of locating the pin and detecting the pin sites in thermal images efficiently, exactly, and reliably for extracting pin site temperatures. A total of 1708 pin sites was investigated with Thermography and augmented by 9 different methods in to totally 10.409 images. The dataset was divided into a training set (n=8325), a validation set (n=1040), and a test set (n=1044) of images. The Pin Detection Model (PDM) was developed as follows: A You Only Look Once (YOLOv5) based object detection model with a Complete Detection Intersection over Union (CDIoU), it was pre-trained and finetuned by the through transfer learning. The basic performance of the YOLOv5 with CDIoU model was compared with other conventional models (FCOS and YOLOv4) for deep and transition learning to improve performance and precision. Maximum Temperature Extraction (MTE) Based on Region of Interest (ROI) for all pin sites was generated by the model. Inference of MTE using PDM with infected and un-infected datasets was investigated. An automatic tool that can identify and annotate pin sites on conventional images using bounding boxes was established. The bounding box was transferred to the infrared image. The PMD algorithm was built on YOLOv5 with CDIoU and has a precision of 0.976. The model offers the pin site detection in 1.8 milliseconds. The thermal data from ROI at the pin site was automatically extracted. These results enable automatic pin site annotation on thermography. The model tracks the correlation between temperature and infection from the detected pin sites and demonstrates it is a promising tool for automatic pin site detection and maximum temperature extraction for further infection studies. Our work for automatic pin site annotation on thermography paves the way for future research on infection assessment using thermography

Introduction. The concept and method of repeatedly connecting an extracorporeal blood pump to produce elevated pancycle inflow pressures to ischaemic limbs is presented. The aim of this study was to determine if intermittent increased perfusion would improve the clinical picture in peripheral arterial disease. Methods. Animal studies—to determine the safety and efficacy of the pumping and the access device were performed on 12 sheep. Following successful completion of that study, pilot studies of 18 patients were treated using the Peripheral Access Device (PAD) and Hypertensive Extracorporeal Limb Hyperperfusion (HELP). Treatment was offered to patients who had no other alternative than major amputation. Patients were treated for less than 100 hours of total pumping, broken over three or less treatment periods over approximately one week. Improvement was measured by pain scores, clinical examination and digital thermography. Results. In all cases access and desired flow parameters were shown to be reliably achieved. In all cases an improvement was found to peripheral circulation, with the longest follow up at more than three years and mean CFI improving from 0.6 to 1.1. Mortality and infection rates in the pilot study were lower than expected for amputation, with a third of patients retaining their limbs. Conclusion. It is shown that blood flow through collaterals can be very significantly augmented by the HELP treatment and that pancycle hyperperfusion can be safely repeated by implantation of the PAD arterial access device, offering a potential new treatment modality for Critical Limb Ischaemia

Thermonecrosis either results in bone loss which may weaken the purchase of surgically-inserted screws leading to loosening or the dead bone may remain in situ and become infected resulting in a ring sequestrum. The aim of this project was to measure the heat generated during drilling of bone. By using a novel realtime thermal camera the thermal events could be visualised topographically. An experimental setup comprising a force table, an infrared camera, a power drill and a new surgical 2.5mm drill bit was constructed. This enabled measurements of the force applied and temperature changes in sheep cortical bone during a drilling operation. The temperature was observed throughout the drilling period and for further 15s after the drill bit was withdrawn. Images were grabbed using a LAND FTI Mv thermal camera which was driven by LIPS Mini software. Calibration was made in the range 20-200 degrees C, the upper value being provided by a high wattage resistor. Data was processed using routines written in MATLAB. It was found that 12s were required to drill through a single cortex. Within one second of drilling, the maximum recorded temperature in the vicinity of the drill increased from the baseline of 20 to 170 degrees C. It remained above this temperature for 25s. Immediately after the drill bit was withdrawn, a region of approximately 15mm of diameter of cortical surface had a sustained temperature above 50 degrees C. After 15s of cooling, this diameter had only reduced to 10mm. By modelling the cooling curve, the maximum temperature at the drill tip was extrapolated to be between 500-600 degrees C. Thermography has proven to be useful in the study of the thermal characteristics of bone during drilling. The process of drilling generates significant increase in temperature in the vicinity of the drill. This temperature elevation has been found to be sustained for a significant period of time

Reflex sympathetic dystrophy is a syndrome characterised by pain and hyperaesthesia associated with swelling, vasomotor instability and dystrophic changes of the skin. It is rare in children, can occur without any previous history of significant trauma and may be recurrent and migratory. We reported 13 new cases of RSD in children and emphasised the role of a multidisciplinary team approach in management. A review of the literature was included. 13 children (3 boys and 10 girls) with reflex sympathetic dystrophy were presented. They were aged between 8 and 17 years. Mean age at onset was 13 years 4 months. All of them had RSD involving the lower limbs. Thermography was performed in 10 cases. The average time to correct diagnosis was 4 months. Five ankles, 4 knees and 5 hips were involved (14 joints in 13 cases). Psychological assessments revealed abnormalities in all cases. Pain (visual analogue score) and function were assessed before and after treatment. The most common therapy in children is progressive mobilisation supported by analgesic drugs, psychological and physical therapy. We individualised the therapy for each child. A team-care approach with the physiotherapist, psychologist and pain-care team co-ordinated by the Orthopaedic Consultant was the essence of our management. All children received physical therapy including a wide variety of non-standarised approaches involving analgesics and hydrotherapy. 5 patients received guanithidine blocks. Individual therapy was monitored with set achievable goals and weekly assessment of progression of mobility and joint motion. Time from the first RSD episode to resolution averaged 6 months in our series [it was mean 10 weeks in the non-adolescent cases (8 cases) and 7 months in the adolescent one (5 cases)]. The pain and function scores improved remarkably in all patients. RSD in children is not a widely recognised condition. There is often a delay in diagnosis in view of the rarity of the condition as well as the fact that specific diagnostic modalities are not readily available in all centres. Psychological factors should not be underestimated. Early diagnosis with an aggressive, multidisciplinary, monitored, ‘goal-oriented’ team approach should be the basis of management in these cases

Background: The mechanism of tissue removal and residual tissue damage for ultrasonic ablation instruments have not been adequately investigated. In particular, the relationship between applied force and amplitude of distal tip displacement as determinants of cutting effect and residual tissue damage has not been clearly defined. Recent clinical studies have highlighted the potentially deleterious thermal and mechanical effect of ultrasonic energy in residual tissue. Aims: To evaluate the role of ultrasonic tissue resection as an alternative to mechanical shaver and electrosurgical resection for orthopaedic applications. We aim to investigate factors influencing material removal rate (MRR), cutting rate (CR) and thermal damage for meniscus tissue resection using an experimental 20kHz ultrasonic ablation device. Methods: An experimental force controlled testing rig was constructed using a 20kHz ultrasonic probe suspended vertically from a load cell. Ex-vivo bovine meniscus samples were harvested from knee joints and cut into uniform 16mm discs. Effect of variation in force (2.5–4.5N) and amplitude of distal tip displacement (242–494μm peak-peak) settings on material removal rate (MRR) and cutting (CR) was analyzed. Time-discrete temperature elevation in the meniscus was measured by embedded thermocouples and infrared thermography. Statistical analysis was conducted using SPSS v.11.0 (SPSS Inc., Chicago, IL). The experiment was designed using a response surface quadratic model with both input variables treated as continuous, using Design-Expert v.7.1.3 (Stat-Ease Inc., Minneapolis, MN). Results: As either force or amplitude increases, there is a linear increase in MRR (Mean±SD: 0.9±0.4 to 11.2±4.9mg/s). A corresponding increase is observed in CR for increases in force and amplitude (Mean±SD: 0.08±0.04 to 0.73±0.18mm/s). Conversely, there is an inverse relationship between both force and amplitude, and temperature elevation, with higher force and amplitude settings resulting in less thermal damage. Maximum mean temperatures of 84.6±12.1°C and 52.3±10.9°C were recorded in residual tissue at 2mm and 4mm from the ultrasound probe-tissue interface respectively. Conclusions: Although high power low frequency ultrasound is capable of meniscal resection, key limitations of this technology are low MRR rate and thermal damage. The mechanism of removal is primarily thermal, with tissue temperatures reaching potentially dangerous levels. Control of user force and amplitude of tip displacement settings in ultrasonic instrument design can maintain temperature peaks below critical temperatures of thermal necrosis during operation

The December 2014 Hip & Pelvis Roundup³⁶⁰ looks at: Sports and total hips; topical tranexamic acid and blood conservation in hip replacement; blind spots and biases in hip research; no recurrence in cam lesions at two years; to drain or not to drain?; sonication and diagnosis of implant associated infection; and biomarkers and periprosthetic infection