This is quite an innovative study that should lead to a multicentre validation trial. We have developed an FDG-PET/MRI texture-based model for the prediction of lung metastases (LM) in newly diagnosed patients with soft-tissue sarcomas (STSs) using retrospective analysis. In this work, we assess the model performance using a new prospective STS cohort. We also investigate whether incorporating hypoxia and perfusion biomarkers derived from FMISO-PET and DCE-MRI scans can further enhance the predictive power of the model. A total of 66 patients with histologically confirmed STSs were used in this study and divided into two groups: a retrospective cohort of 51 patients (19 LM) used for training the model, and a prospective cohort of 15 patients (two patients with LM, one patient with bone metastases and suspicious lung nodules) for testing the model. In the training phase, a model of four texture features characterising tumour sub-region size and intensity heterogeneities was developed for LM prediction from pre-treatment FDG-PET and MRI scans (T1-weighted, T2-weighted with fat saturation) of the retrospective cohort, using imbalance-adjusted bootstrap statistical resampling and logistic regression multivariable modeling. In the testing phase, this multivariable model was applied to predict the distant metastasis status of the prospective cohort. The predictive power of the obtained model response was assessed using the area under the receiver-operating characteristic curve (AUC). In the exploratory phase of the study, we extracted two heterogeneity metrics from the prospective cohort: the area under the intensity-volume histogram of pre-treatment DCE-MRI volume transfer constant parametric maps and FMISO-PET hypoxia maps (AU-IVH-Ktrans, AU-IVH-FMISO). The impact of the addition of these two individual metrics to the texture-based model response obtained in the testing phase was first investigated using Spearman's correlation (rs), and lastly using logistic regression and leave-one-out cross-validation (LOO-CV) to account for overfitting bias. First, the texture-based model reached an AUC of 0.94, a sensitivity of 1, a specificity of 0.83 and an accuracy of 0.87 when tested in the prospective cohort. In the exploratory phase, the addition of AU-IVH-FMISO did not improve predictive power, yielding a correlation of rs = −0.42 (p = 0.12) with lung metastases, and a relative change in validation AUC of 0% in comparison with the texture-based model response alone in LOO-CV experiments. In contrast, the addition of AU-IVH-Ktrans improved predictive power, yielding a correlation of rs = −0.54 (p = 0.04) with lung metastases, and a change in validation AUC of +10%. Our results demonstrate that texture-based models extracted from pre-treatment FDG-PET and MRI anatomical scans could be successfully used to predict distant metastases in STS cancer. Our results also suggest that the addition of perfusion heterogeneity metrics may contribute to improving model prediction performance

Dual plating of the medial and lateral distal femur has been proposed to reduce angular malunion and hardware failure secondary to delayed union or nonunion. This strategy improves the strength and alignment of the construct, but it may compromise the vascularity of the distal femur paradoxically impairing healing. This study investigates the effect of dual plating versus single plating on the perfusion of the distal femur. Ten matched pairs of fresh-frozen cadaveric lower extremities were assigned to either isolated lateral plating or dual plating of a single limb. The contralateral lower extremity was used as a matched control. A distal femoral locking plate was applied to the lateral side of ten legs using a standard sub-vastus approach. Five femurs had an additional 3.5mm reconstruction plate applied to the medial aspect of the distal femur using a medial sub-vastus approach. The superficial femoral artery and the profunda femoris were cannulated at the level of the femoral head. Gadolinium MRI contrast solution (3:1 gadolinium to saline ration) was injected through the arterial cannula. High resolution fat-suppressed 3D gradient echo sequences were completed both with and without gadolinium contrast. Intra-osseous contributions were quantified within a standardized region of interest (ROI) using customized IDL 6.4 software (Exelis, Boulder, CO). Perfusion of the distal femur was assessed in six different zones. The signal intensity on MRI was then quantified in the distal femur and comparison was made between the experimental plated limb and the contralateral, control limb. Following completion of the MRI protocol, the specimens were injected with latex medium and the extra-osseous vasculature was dissected. Quantitative MRI revealed that application of the lateral distal femoral locking plate reduced the perfusion of the distal femur by 21.7%. Within the dual plating group there was a reduction in perfusion by 24%. There was no significant difference in the perfusion between the isolated lateral plate and the dual plating groups. There were no regional differences in perfusion between the epiphyseal, metaphyseal or meta-diaphyseal regions. Specimen dissection in both plating groups revealed complete destruction of any periosteal vessels that ran underneath either the medial or lateral plates. Multiple small vessels enter the posterior condyles off both superior medial and lateral geniculate arteries and were preserved in all specimens. Furthermore, there was retrograde flow to the distal most aspect of the condyles medially and laterally via the inferior geniculate arteries. The medial vascular pedicle was proximal to the medial plate in all the dual plated specimens and was not disrupted by the medial sub-vastus approach in any specimens. Fixation of the distal femur via a lateral sub-vastus approach and application of a lateral locking plate results in a 21% reduction in perfusion to the distal femur. The addition of a medial 3.5mm reconstruction plate does not significantly compromise the vascularity of the distal femur. The majority of the vascular insult secondary to open reduction, internal fixation of the distal femur occurs with application of the lateral locking plate

Background and aim. In 2019, specific diagnostic and antibiotic treatment recommendations for diabetic foot infection (DFI) and osteomyelitis (DFO) were introduced in our institution. They include principles on numbers of biopsies to obtain for microbiological/histopathological examinations, labeling anatomic localization, and antibiotic treatment (ABT) duration based on the aforementioned findings. ABT should be stopped after complete resection of infected bone. In case of incomplete resection, treatment is continued for 4–6 weeks. Two years after the introduction of these recommendations, we investigated the degree of implementation for hospitalized patients. Method. Adult patients with DFI/DFO undergoing surgical intervention from 01/2019–12/2021 were reviewed retrospectively. Diagnostic procedures were assigned to each episode when performed ≤30 days before surgical invention. Chi-square and Mann-Whitney-U tests were performed where appropriate. Results. We included 80 patients with 117 hospital episodes and 163 surgical interventions (mean 1.5 episodes and 2 interventions per patient). The mean age was 69.6 (SD 11.5) years, 75% were male. Vascular examination and MRI were performed in 70.9% and 74.4% of episodes, respectively. Impaired perfusion and DFO were confirmed in 34.9% and 56.3%, respectively. Blood cultures were sampled in 34.2%, bacteremia detected in 7.7% with S. aureus being the most common microorganism. Biopsies were obtained in 71.8% of operations, in 90.5% of those 3–5 samples. These were sent for histological examination in 63.2% of the interventions. In 43.6% the anatomic location was labeled ‘proximal to the resection margin’. Preoperative antibiotics were administered in 41.9% of the episodes because of concomitant soft-tissue infections. The most commonly used compound was amoxicillin/clavulanate (74.4%). ABT duration varied significantly when there were signs of DFO in preoperative MRI (p=0.015). The mean duration of antibiotic therapy was 9 (IQR 5–15) days in surgically cured episodes and 40.5 (IQR 15–42) days in cases with resection margins in non-healthy bone (p<0.0001). The results were similar when analyzing treatment duration with respect to osteomyelitis in histology: 13 (IQR 8–42) versus 29 (IQR 13–42) days, respectively (p=0.026). Conclusions. The adherence to recommendations in terms of biopsy sampling was excellent, moderate for sending samples to histology and poor for labeling the anatomic location. The adherence to ABT duration was good but can be improved by shortening treatment duration for surgically cured cases. Results of preoperative MRI appear to be influential on the decision-making for treatment duration

Introduction:. Although the risk of pulmonary embolism (PE) or other embolic events associated with total joint arthroplasty have been recorded for some time, to date no direct means of these events in human arthroplasty have reported. This prospective study was designed to clarify the pathophysiologic mechanism of PE after total knee arthroplasty (TKA). Methods:. Nine patients fulfilling the following selection criteria were included in this prospective study: diagnosis of osteoarthosis, age 60 to 75 years, cemented primary TKA. All patients had a baseline pulmonary perfusion scan 2 days prior to the surgery. TKA was performed in the standard manner under general anesthesia. Monitoring of the heart chambers during the course of the TKA was performed using a 5 MHz ultrasonic transducer placed into the esophagus. The 4-chamber view plane of the heart was then imaged using a 2-dimensional echocardiography. A tip of the catheter inserted from the contralateral femoral vein was also placed in the inferior vena cava to harvest the venous blood flowed from the suffered lower extremity before and after tourniquet release. All patients had pulmonary perfusion scans 3 hours after TKA and on the 21st postoperative day. The ventilation-perfusion scan was compared with the baseline perfusion scan. Results:. No symptomatic PE were identified. Using transesophageal echocardiographic monitoring, the heaviest flow of embolic particles in the right heart was observed 2 seconds after tourniquet release and lasted approximately 30 seconds. By squeezing the calf muscle, the heavy flow of embolic particles was again observed. The venous blood harvested through the catheter after tourniquet release had fat droplets and white coagula. All of patients had pulmonary perfusion defects 3 hours after TKA, but no pulmonary perfusion defects on the 21st postoperative day. Discussion and Conclusions:. Substantial amounts of embolic materials were seen in the right heart using transesophageal echocardiography in patients operated in the standard manner. It was demonstrated that these embolic materials consisted of fat droplets and white coagula. We also demonstrated that many embolic materials for PE and/or DVT originated in the calf. All of patients had pulmonary perfusion defects just after TKA. It was concluded that all of the patients who underwent TKA had asymptomatic PE just after the surgery. Therefore, all of the patients have a possibility of symptomatic PE just after TKA

Introduction:. A surgical hip dislocation provides circumferential access to the femoral head and is essential in the treatment pediatric and adult hip disease. Iatrogenic injury to the femoral head blood supply during a surgical may result in the osteonecrosis of the femoral head. In order to reduce vessel injury and incidence of AVN, the Greater Trochanteric Osteotomy (GTO) was developed and popularized by Ganz. The downside of this approach is the increased morbidity associated with the GTO including non-union in 8% and painful hardware requiring removal in 20% of patients. (reference) Recent studies performed at our institution have mapped the extra-osseous course of the medial femoral circumflex artery and provide surgical guidelines for a vessel preserving posterolateral approach. In this cadaveric model using Gadolinium enhanced MRI, we investigate whether standardized alterations in the postero-lateral surgical approach may reliably preserve femoral head vascularity during a posterior surgical hip dislocation. Methods:. In 8 cadaveric specimens the senior author (ES) performed a surgical hip dislocation through the posterolateral approach with surgical modifications designed to protect the superior and inferior retinacular arteries. In every specimen the same surgical alterations were made using a ruler: the Quadratus Femoris myotomy occurred 2.5 cm off its trochanteric insertion, the piriformis tenotomy occurred at its insertion and extended obliquely leaving a 2 cm cuff of conjoin tendon (inferior gemellus), and the Obturator Externus (OE) was myotomized 2 cm off its trochanteric insertion. (Figure 1) For the capsulotomy, the incision started on the posterior femoral neck directly beneath the cut obturator externus tendon and extending posteriorly to the acetabulum. Superior and inferior extensions of the capsulotomy ran parallel to the acetabular rim creating a T-shaped capsulotomy. After the surgical dislocation was complete, the medial femoral circumflex artery (MFCA) was cannulated and Gadolinium-enhanced MRI performed in order to assess intra-osseous femoral head perfusion and compared to the gadolinium femoral head perfusion of the contra-lateral hip as a non-operative control. Gross-dissection after polyurethane latex injection in the cannulated MFCA was performed to validate MRI findings and to assess for vessel integrity after the surgical dislocation. Results:. In 8 cadaveric specimens MRI quantification of femoral head perfusion was 94.3% and femoral head-neck junction perfusion was 93.5% compared to the non-operative control. (Figure 2) Gross dissection after latex injection into the MFCA demonstrated intact superior and inferior retinacular arteries in all 8 specimens. (Figure 3). Discussion and Conclusions:. In this study, perfusion to the femoral head and head-neck junction is preserved following posterior surgical dislocation through the postero-lateral approach. These preliminary findings suggest that specific surgical modifications can protect and reliably maintain vascularity to the femoral head after surgical hip dislocation. This approach may benefit hip resurfacing and potentially decease risk of femoral neck fracture secondary to osteonecrosis. In addition this may allow a vascular preserving surgical hip dislocation to be performed without the need for a GTO

Background. Non-invasive hemoglobin measurement was introduced to potentially eliminate blood draws postoperatively. We compared the accuracy and effectiveness of a non-invasive hemoglobin measurement system with a traditional blood draw in patients undergoing total joint arthroplasty. Methods. After IRB approval, 100 consecutive patients undergoing primary total hip or knee arthroplasty had their hemoglobin level tested by both traditional blood draw and a non-invasive hemoglobin monitoring system. Results were analyzed for the entire group, further stratifying patients based on gender, race, surgery (THA versus TKA), and post-operative hemoglobin level. Finally, we compared financial implications and patient satisfaction with the device. Paired t-test with 0.05 conferring significance was used. Stratified analyses of the absolute difference between the two measures were assessed using Mann- Whitney test. To assess the level of agreement between the two measures, the concordance correlation coefficient (CCC) was calculated. Results. Mean blood-draw hemoglobin value on POD1 was 11.063 ± 1.39 g/dL and 11.192 ± 1.333 g/dL with the non-invasive device. For all patients, the mean absolute difference between the two methods was 0.13 g/dL (p = 0.30). The CCC between the two methods was 0.58, conferring a moderate to strongly positive linear relationship (Figure 1). Non-invasive measurement was preferred by 100% of patients with a mean VAS score of 0/10. Additionally, the cost savings with the non-invasive system was $16.50 per patient. Discussion. Overall, there was no significant difference between the hemoglobin level obtained by traditional laboratory methods versus the Masimo Radical-7 system on post-operative day #1 in patients who underwent total joint arthroplasty. In the minority of patients (19%) who had a hemoglobin level of less than 10 g/dL, the difference between the two methods was statistically significant. Additionally, 100% of patients preferred the Masimo device to a traditional blood draw and the Masimo device was substantially cheaper. While further investigation of non-invasive hemoglobin monitoring systems is necessary, particularly in patients with a post-operative hemoglobin of less than 10 g/dL, our study shows that the Masimo Radical-7 device provides an accurate, preferable, and less expensive alternative to a traditional blood draw after total joint replacement. Conclusion. Overall, the non-invasive hemoglobin monitoring system offered a similar hemoglobin reading to the standard lab-draw reading, while improving satisfaction and lowering cost. The system relies on adequate perfusion for measurement, and our study demonstrated that lower hemoglobin values may reduce finger-tip perfusion and affect the hemoglobin reading

Intraosseous pressure measurements (IOP) are not new. Several authors have struggled to interpret static IOP and to understand arthritis and osteonecrosis pathology. This work uses a combination of simple experiments in vivo to reassess bone and joint physiology. Joint replacement needs to take into account the hydrodynamic conditions that are present in bone. Intraosseous pressure measurements were carried out with vascular occlusion, activity and saline injection in experimental conditions and then in man during walking. RESULTS. 1. Basal IOP has a pulse wave and an underlying respiratory wave (RW). 2. IOP closely reflects systemic vascular changes. 3. Proximal arterial occlusion causes loss of IOP (IOPa) and pulse volume (PV). 4. Proximal vein occlusion causes a rise in IOP (IOPv) with preservation of PV and RW. 5. Physical loading raises IOP with preservation of PV and RW. 6. Load with arterial occlusion caused minimal rise in IOP. Loading with venous occlusion caused an augmented rise in IOP with preservation of the PV. 7. Simultaneous recordings from the femoral head, condyle and upper tibia during vascular occlusion and loading show that the same effects occur at all sites. 8. Simultaneous recording from the femoral head, condyle and upper tibia during saline injection shows pressure is transmitted through bone but not across joints. 9. The Ficat bolus test destroys local circulation. Aspiration is better and preserves local perfusion. 10. Bone health at the needle tip is better assessed by IOPv – IOPa, the perfusion ‘bandwidth’. 11. Upper tibial pressure during standing, slow walking and fast walking shows large IOP changes in vivo. 12. There is probably a physiological subchondral bone blood pump. 13. Anatomical features are present which support this idea. CONCLUSIONS. IOP measurement in isolation is meaningless. With arterial and venous occlusion, perfusion at the needle tip can be studied. Compartment syndrome testing should be similar. Subchondral bone is a compressible perfused sponge with a ‘pumped’ microcirculation. Very high pressures arise in subchondral bone during activity. There are protective modifications of the microcirculation. Failure of subchondral circulation causes arthritis. Arthritis is mainly a ‘vasculo-mechanical’ disease. This work explains the spectrum of arthritis and osteonecrosis, and Perthes, caisson and sickle cell disease patterns. It explains why osteoporosis might protect against arthritis

Despite recent advances in the management of slipped capital femoral epiphysis (SCFE), controversy remains about the treatment of choice for unstable slips. Surgical dislocation and open reduction has the advantage of identifying and preserving the blood supply of femoral head thereby potentially reducing the risk of avascular necrosis, (AVN). There is large variation in the literature from several small series about reported AVN rates ranging from two to 66% for unstable SCFE treated with surgical dislocation. The aim of our study was to analyze our experience with acute open reduction and internal fixation of unstable acute and unstable acute on chronic slips using the technique of surgical dislocation described by Professor Reinhold Ganz. A retrospective review of 11 patients (12 hips) treated by surgical dislocation, reduction and pinning as the primary procedure for unstable acute and unstable acute on chronic SCFE in a tertiary referral children's hospital was undertaken. This represents the entire series treated in this manner from September 2007 to January 2018. These procedures were performed by a team of Orthopaedic surgeons with significant experience performing surgical dislocation of the hip including patients with chronic SCFE, Perthes' disease, impingement and acetabular fractures. Demographic data, intraoperative records, postoperative notes and radiographs including details of subsequent surgery were reviewed. There were seven boys and four girls with mean age of 13.4 years, range 11 to 15 years at the time of surgical dislocation. Out of 12 hips, two had acute unstable slip while the remaining 10 had acute on chronic unstable slip. Six patients had good or excellent results. The remaining six patients developed AVN of which three patients had total hip replacement at six months, 17 months and 18 months following primary procedure. Seven patients required more than one operation. Three patients lost their correction and required re fixation despite surgical dislocation, reduction and fixation being their primary procedure. This series demonstrates a high percentage of AVN (50%) in severe unstable SCFE treated with surgical dislocation despite careful attention to retinacular flap development and intra operative doppler studies. This is in direct contrast to our experience with subcapital reorientation with surgical dislocation in stable slips where excellent results were achieved with a low rate of AVN. Pre-operative imaging with MRI and perfusion studies may identify where ischemia has occurred and might influence operative treatment. Based on our results, we do not recommend routine use of surgical dislocation in unstable SCFE. This technique requires further scrutiny to define the operative indications in unstable SCFE

Infection following total knee arthroplasty (TKA) can cause significant morbidity to the patient and be associated with significant costs and burdens to the healthcare system. Wound complications often initiate the cascade that can eventually lead to deep infection and implant failure. Galat et al. reported that wound complications following TKA requiring surgical treatment were associated with 2-year cumulative risks of major reoperation and deep infection of 5.3% and 6.0%, respectively. Consequently, developing a systematic approach to the management of wound problems following TKA can potentially minimise subsequent complications. Unlike the hip, the vascular supply to the soft tissue envelope to the knee is less robust and more sensitive to the trauma of surgery. Therefore, proper soft tissue handling and wound closure at the time of surgery can minimise potential wound drainage and breakdown postoperatively. Kim et al. showed, using a meta-analysis of the literature, that primary skin closure with staples demonstrated lower wound complications, decreased closure times, and lower resource utilization compared to sutures. However, a running subcuticular closure enables the most robust skin perfusion following TKA. Finally, the use of hydrofiber surgical dressings following surgery was associated with increased patient comfort and satisfaction and reduced the incidence of superficial surgical site infection. A wound complication following TKA needs to be managed systematically and aggressively. A determination of whether the extent of the involvement is superficial or deep is critical. Antibiotics should not be started without first excluding the possibility of a deep infection. Weiss and Krackow recommended return to the operating room for wound drainage persisting beyond 7 days. While incisional negative pressure wound therapy can occasionally salvage the “at risk” draining wound following TKA, its utilization should be limited only to the time immediately following surgery and should not delay formal surgical debridement, if indicated. Finally, early wound flap coverage and co-management of wound complications with plastic surgery is associated with increased rates of prosthesis retention and limb salvage

Infection following total knee arthroplasty (TKA) can cause significant morbidity to the patient and be associated with significant costs and burdens to the health care system. Wound complications often initiate the cascade that can eventually lead to deep infection and implant failure. Galat et al. reported that wound complications following TKA requiring surgical treatment were associated with a 2-year cumulative risk of major reoperation and deep infection of 5.3% and 6.0%, respectively. Consequently, developing a systematic approach to the management of wound problems following TKA can potentially minimise subsequent complications. Unlike the hip, the vascular supply to the soft tissue envelope to the knee is less robust and more sensitive to the trauma of surgery. Therefore, proper soft tissue handling and wound closure at the time of surgery can minimise potential wound drainage and breakdown post-operatively. Kim et al. showed, using a meta-analysis of the literature, that primary skin closure with staples demonstrated lower wound complications, decreased closure times, and lower resource utilization compared to sutures. However, a running subcuticular closure enables the most robust skin perfusion following TKA. Finally, the use of hydrofiber surgical dressings following surgery was associated with increased patient comfort and satisfaction and reduced the incidence of superficial surgical site infection. A wound complication following TKA needs to be managed systematically and aggressively. A determination of whether the extent of the involvement is superficial or deep is critical. Antibiotics should not be started without first excluding the possibility of a deep infection. Weiss and Krackow recommended return to the operating room for wound drainage persisting beyond 7 days. While incisional negative pressure wound therapy can occasionally salvage the “at risk” draining wound following TKA, its utilization should be limited only to the time immediately following surgery and should not delay formal surgical debridement, if indicated. Finally, early wound flap coverage and co-management of wound complications with plastics surgery is associated with increased rates of prosthesis retention and limb salvage

Wound closure is not often an area that is discussed by orthopaedic surgeons. We commonly attend meetings and talks related to different types of implants and surgical technique but in reality the wound and how we close it maybe one of the most important aspects of a surgical procedure. The avoidance of wound complications such as unplanned clinic visits, readmissions, reoperations and deep infections are very important as we move into a world of bundled payments and public reporting of complications. Not to mention the poor results for the patients when wound complications occur. Often there is little thought about how wound closure and surgical dressings could affect surgical site healing. We all have a common belief that blisters, drainage and surgical site infections are rare. In the literature it has been shown that the method of wound closure can influence skin and soft tissue perfusion. Which closure techniques can achieve physiologic blood flow, which may improve wound healing? This talk will cover topics related to reducing the dead space, avoidance of hematoma formation and what the literature says regarding different types of wound closure materials

Obtaining primary wound healing in total joint arthroplasty (TJA) is essential to a good result. Wound healing disturbances (WHD) can occur and the consequences can be devastating to the patient and to the surgeon. Determination of the host healing capacity can be useful in predicting complications. Cierney and Mader classified patients as Type A: no healing compromises and Type B: systemic or local healing compromise factors present. Local factors include traumatic arthritis with multiple previous incisions, extensive scarring, lymphodema, poor vascular perfusion, and excessive local adipose deposition. Systemic compromising factors include diabetes, rheumatic diseases, renal or liver disease, immunocompromise, steroids, smoking, and poor nutrition. Low serum albumin, total lymphocyte count, and low transferrin increase WHD. In high risk situations the surgeon should encourage positive patient choices such as smoking cessation and nutritional supplementation to modify healing responses. Use of tourniquet in obese patients also increases WHD. Careful planning of incisions, particularly in patients with scarring or multiple previous operations, is productive. Around the knee the vascular viability is better in the medial flap. Thusly, use the most lateral previous incision, do minimal undermining, and handle tissue meticulously. We do all potentially complicated TKA's without tourniquet to enhance blood flow and tissue viability. The use of perioperative anticoagulation will increase wound problems. If wound drainage or healing problems do occur, immediate action is required. Deep sepsis can be ruled out with a joint aspiration and cell count (less than 2500), differential (less than 60% polys), and negative culture and sensitivity. All hematomas should be evacuated and necrosis or dehiscence should be managed by debridement to obtain a live wound

Obtaining primary wound healing in Total Joint Arthroplasty (TJA) is essential to a good result. Wound healing problems can occur and the consequences can be devastating to the patient and to the surgeon. Determination of the host healing capacity can be useful in predicting complications. Cierney and Mader classified patients as Type A: no healing compromises and Type B: systemic or local healing compromises factors present. Local factors include traumatic arthritis with multiple previous incisions, extensive scarring, lymphedema, poor vascular perfusion, and excessive local adipose deposition. Systemic compromising factors include diabetes, rheumatic diseases, renal or liver disease, immunocompromise, steroids, smoking, and poor nutrition. In high risk situations the surgeon should encourage positive patient choices such as smoking cessation and nutritional supplementation to elevate the total lymphocyte count and total albumin. Careful planning of incisions, particularly in patients with scarring or multiple previous operations, is productive. Around the knee the vascular viability is better in the medial flap. Thusly, use the most lateral previous incision, do minimal undermining, and handle tissue meticulously. We do all potentially complicated TKAs without tourniquet to enhance blood flow and tissue viability. The use of peri-operative anticoagulation will increase wound problems. If wound drainage or healing problems do occur immediate action is required. Deep sepsis can be ruled out with a joint aspiration and cell count [less than 2500], differential [less than 60% polys], and negative culture and sensitivity. All hematomas should be evacuated and necrosis or dehiscence should be managed by debridement to obtain a live wound

Major upper limb arterial injuries sustained in combat are associated with significant trauma. We analysed the survival and complication rates following upper limb vascular injury in Iraq and Afghanistan (2004–2014). Fifty-two soldiers sustained 59 major arterial injuries in 54 limbs. Axillary artery injuries were more likely to be caused by gunshot wounds (86%), whilst brachial and ulnar artery injuries were primarily associated with blasts (72% and 87% respectively); no such correlation was identified with radial artery injuries. Apart from three temporary shunts, all vascular injuries were treated definitively in the local field hospital before repatriation. Proximal injuries were predominantly treated with long saphenous vein grafts and distal injuries with ligation. One soldier required an immediate amputation following failed LSV grafting, however no amputations followed repatriation. There were five identified graft failures (21%), although these were not associated with subsequent perfusion issues. There were no graft failures following temporary shunting. Associated nerve injuries often required operative intervention and have a guarded outcome. 100% of radial fractures went onto non-union if combined with a radial artery injury. Successful immediate re-perfusion of a vascular compromised upper limb correlates with excellent long-term limb survival, despite a significant number of grafts developing secondary failure

Cadaveric specimens that have been fresh-frozen and then thawed for use have historically been considered to be the gold standard for biomechanical studies and the closest surrogate to living tissue. However, there are notable issues related to specimen rapid decay in the thawed state as well as infectious hazard to those handling the specimens. Cadaveric specimen preparation using a new phenol-based soft-embalmed method has shown considerable promise in preserving tissue in a prolonged fresh-like state while mitigating the infection risk. In this study, we evaluated the ability of soft-embalmed specimens to replace fresh-frozen specimens in the biomechanical study of flexor tendon repair. An ex-vivo study was conducted on six cadaveric hands in both a fresh-frozen, thawed state and following embalming with a phenol-based solution. Six different combinations of flexor digitorum profundus (FDP) tendons, from D2 to D5, and flexor pollicis longus (FPL) tendons were used to create two groups of similar composition with 15 tendons each, one group to be tested fresh and the other following embalming. A 5cm length of each flexor tendon was harvested from zone 2 and transversely cut at the mid-section. A modified-Kessler repair was performed on each specimen using 4–0 Fiberwire, with two core sutures and 1cm purchase on each end. Incisions were closed with a running stitch to prepare the specimen for embalming. The same protocol was used to repair and harvest the second group of tendons one month following the perfusion of a phenol-based solution through the vasculature of the hand and forearm. Tendon repair biomechanics were characterised through a ramp loading to failure (rate 1mm/sec), incorporating the 12 mm travel distance of the testing machine. A video-extensometry technique was used to validate machine recordings for the repair site for force at the 2mm gap distance, the ultimate strength, and the mode of failure. Characteristics of the two groups were tested for equivalency using inferential confidence intervals (ICI). Both fresh and embalmed groups were indistinguishable in both force at 2mm gap (fresh 17.9±4.7N; embalmed 18.1±5.1) and ultimate strength (fresh 43.93±10.0; embalmed 43.7±9.4). With the exception of one specimen with complete suture pull-out, all specimens exhibited partial pull-out as the final mode of failure. Our study demonstrated that tendon repair characteristics of phenol-embalmed specimens were equivalent to fresh specimens. Post-mortem chemical preservation can indeed preserve both visual and biomechanical characteristics of soft tissues. This study opens new avenues in support of the use of embalmed specimens in medical curricula and surgical training

Introduction. Computer Tomography (CT) imaging has been limited to beam hardening artefacts until now. Literature has failed to describe sensitivity and specifity for loosening of endoprothesis in CTs, as metal artefacts have always influenced the diagnostic value of CTs. In recent years a new technology has been developed, the Dual Energy CT. Dual Energy CT scanners simultaneously scan with two tubes at different energy levels, most commonly 100kVp and 140kVp. Furthermore pictures gained from Dual Energy CTs are post-processed with monoenergetic reconstruction, which increases picture quality while further reducing metal artefacts. This promising technology has increased the diagnostic value preventing more radiation for the patients, for example in detection of kidney stones or to map lung perfusion. In the musculoskeletal imaging it has not been established yet and further clinical investigations are necessary. Thus the aim of this study is to describe sensitivity and sensibility for endoprothesis loosening of this novel technology. Material and Methods. 53 prospective patients (31 total hip- and 22 total knee-arthoplasties) who were planned for revision surgery underwent preoperative Dual Energy CT examination. All scans were performed with a second-generation, dual-energy multi-detector CT scanner. And all pictures were post-processed with monoenergetic reconstruction. Radiologists were blinded for patient´s history. Senior consultants, who are specialized in arthroplasty of the hip and the knee, performed surgery. Intraoperative information was used as gold standard. Results. We pressent the results of the current status of our study. In total hip athroplasty Dual Energy CTs showed a high sensitivity and specifity for cup loosening as well as shaft loosening. In total knee arthroplasty, sensitivity and specifity for the femoral and tibial component also showed high results. Conclusion. Dual Energy CTs provide high sensitivity and specifity for detection of loosening of endoprosthesis. This novel technology has made it possible for the first time to overcome the problem with metal artefacts in CT imaging in the assessment of endoprosthesis. Furthermore, Dual Energy CTs offer a new diagnostic manner for endoprothesis in the future

Transforaminal lumbar interbody fusion (TLIF) using an implanted cage is the gold standard surgical treatment for disc diseases such as disc collapse and spinal cord compression, when more conservative medical therapy fails. Titanium (Ti) alloys are widely used implant materials due to their superior biocompatibility and corrosion resistance. A new Ti-6Al-4V TLIF cage concept featuring an I-beam cross-section was recently proposed, with the intent to allow bone graft to be introduced secondary to cage implantation. In designing this cage, we desire a clear pathway for bone graft to be injected into the implant, and perfused into the surrounding intervertebral space as much as possible. Therefore, we have employed shape optimization to maximize this pathway, subject to maintaining stresses below the thresholds for fatigue or yielding. The TLIF I-beam cage (Fig. 1(a)) with an irregular shape was parametrically designed considering a lumbar lordotic angle of 10°, and an insertion angle of 45° through the left or right Kambin's triangles with respect to the sagittal plane. The overall cage dimensions of 30 mm in length, 11 mm in width and 13 mm in height were chosen based on the dimensions of other commercially available cages. The lengths (la, lp) and widths (wa, wp) of the anterior and posterior beams determine the sizes of the cage's middle and posterior windows for bone graft injection and perfusion, so they were considered as the design variables for shape optimization. Five dynamic tests (extension/flexion bending, lateral bending, torsion, compression and shear compression, as shown in Fig. 2(b)) for assessing long term cage durability (10. 7. cycles), as described in ASTM F2077, were simulated in ANSYS 15.0. The multiaxial stress state in the cage was converted to an equivalent uniaxial stress state using the Manson-Mcknight approach, in order to test the cage based on uniaxial fatigue testing data of Ti-6Al-4V. A fatigue factor (K) and a critical stress (σcr) was introduced by slightly modifying Goodman's equation and von Mises yield criterion, such that a cage design within the safety design region on a Haigh diagram (Fig. 2) must satisfy K ≤ 1 and σcr ≤ SY = 875 MPa (Ti-6Al-4V yield strength) simultaneously. After shape optimization, a final design with la = 2.30 mm, lp = 4.33 mm, wa = 1.20 mm, wp = 2.50 mm, was converged upon, which maximized the sizes of the cage's windows, as well as satisfying the fatigue and yield strength requirements. In terms of the strength of the optimal cage design, the fatigue factor (K) under dynamic torsion approaches 1 and the critical stress (σcr) under dynamic lateral bending approaches the yield strength (SY = 875 MPa), indicating that these two loading scenarios are the most dangerous (Table 1). Future work should further validate whether or not the resulting cage design has reached the true global optimum in the feasible design space. Experimental validation of the candidate TLIF I-beam cage design will be a future focus. For any figures or tables, please contact authors directly (see Info & Metrics tab above).

Since its approval by the FDA two decades ago, Negative Pressure Wound Therapy (NPWT) has become a valuable asset in the management of open fractures with significant soft tissue damage as those seen in high velocity gunshot injuries. These lesions are often associated with grossly contaminated wounds and require a prompt and effective approach. Wound dehiscence and surgical site infection are two of the most common post-operative complications, with poor results when treated with standard gauze dresses. NPTW comes as a legitimate resource promoting secondary intention healing through increased granulation and improved tissue perfusion, as well as continuous local wound drainage preventing bacterial growth and further infection. Recent evidence-based guidelines are still limited for use of NPWT in the treatment of Gustilo-Anderson type IIIB open fractures and there are few cases in literature reporting the management of upper extremity injuries. We present and discuss a successful case of a type IIIB open humeral fracture wound treated with NPWT. A 38-years-old male was admitted to the Emergency Room with a type IIIB open humeral fracture as a result of a gunshot with extensive soft tissue damage. IV antibiotic therapy was promptly started followed by surgical stabilization by intramedullary nailing with primary wound closure. The patient presented an early surgical site infection with wound dehiscence requiring secondary debridement with poor subsequent healing and deficient soft tissue coverage. After ineffective 28 days of standard gauze dresses we started NPWT. NPTW was applied using foam coverage over the dehiscence area with visible results after 13 days and complete granulation of the skin defect by the 28th day. The wound healed completely after 14 weeks of NPWT. The fracture evolved into a painless pseudarthrosis revealing an excellent functional recovery and an acceptable aesthetic result. NPTW is a valuable, effective, and well tolerated resource in the treatment of open fractures with extensive soft tissue damage such as Gustilo-Anderson type IIIB fractures. It should be considered not just as a salvage procedure but as well as a primary option especially in grossly contaminated wounds. No benefits in any form have been received from a commercial party

Our American Academy of Orthopaedic Surgeons (AAOS) and the American College of Chest Physicians (ACCP) have come to a consensus that the use of routine prophylaxis against venous thromboembolism (VTE) is indicated for our patients undergoing total joint arthroplasty. The new guidelines acknowledge differences in efficacy of the various agents and the variable risk of VTE among patients. Agents include warfarin, low molecular weight heparin, aspirin, oral Xa inhibitors, and direct thrombin inhibitors. The use of pneumatic compression devices have been found to be effective in decreasing risk of deep vein thrombosis (DVT) as a stand-alone strategy after total knee arthroplasty (TKA) and is given a level 1C recommendation by ACCP while the data is less strong for use following total hip arthroplasty (THA). Mechanical devices are not associated with an increased bleeding risk, and address the concerns of some surgeons with regard to post-operative bleeding. The availability of mobile compression devices has expanded the indications for use as a result of portability. While the use of mobile pump technology in DVT prophylaxis adds to the armamentarium of tools available for use in VTE risk mitigation, it does not eliminate the need for pharmacologic prophylaxis. While all arthroplasty patients are at elevated risk of VTE, the highest risk is associated with those having a prior history of DVT or pulmonary embolism (PE), having had prior surgery within the preceding three months, or requiring prolonged immobilization post-operatively for any reason. In these patients, thromboprophylaxis with any of a number of agents will play a valuable role in VTE risk reduction. Additionally, not all patients tolerate the use of the pump device. Those individuals with chronic peripheral arterial disease or arterial ulcers in the legs are also poor candidates for mechanical compression strategies which may exacerbate existing vascular compromise and perfusion of the limb. Assessment of the medical comorbidities of the patient may also stratify them to higher risk where the demonstrated benefits of pharmacologic prophylaxis outweigh the considerations of bleeding associated with their use (such as in the morbidly obese/high BMI patients). Mobile pump technology is a valuable adjunct to our VTE reduction strategies, but do not eliminate the need for pharmacologic agents. The judicious selection of DVT prophylaxis strategies based on the totality of the constellation of orthopaedic and medical factors unique to each patient allows us to make clinical decisions tailored to their needs, their risk of VTE, and their reliability in functioning as an active partner in their own post-operative care

An accurate evaluation of the mechanical properties of human tissue is key to understanding and successfully simulating (parts of) human joints. Due to the rapid post-mortem decay, however, the cadavers are usually frozen or embalmed. The main aim of this paper is to quantitatively compare the impact of both techniques on the biomechanical properties. To that extent, the Achilles tendons of seven cadavers have been tested. For each cadaver, one of the Achilles tendons was tested after being frozen for at maximum two weeks, whilst the other tendon was tested following a Thiel embalming process. All specimens were gripped in custom made clamps and subjected to uniaxial tensile loading. The specimens were scanned using a micro-CT to determine their cross-sectional area, which allowed transferring the applied forces to stresses. During the tensile tests, the specimens’ elongation was measured both using the digital image correlation (DIC) technique and using linear variable displacement transducers (LVDT's) mounted across the grips. The former allowed to assess the severity of slip in the grips. As is well described in literature, the obtained stress-strain relationship is not linear (Figure 1). Accordingly, the following bilinear relationship was fitted through the data points using a least squares fit:. s = E. 0. e     e <= ê. s = E0 ê + E (e - ê)     e > ê. As a result, the stress-strain response is sub-divided in two regions: a toe-region (e <= ê) with a low slope and stiffness (E. 0. ) and a linear elastic region (e > ê) with a higher stiffness (E). Both stiffness values were subsequently compared between the fresh frozen and Thiel embalmed group. Given the non-normal distribution of the test data, the non-parametric Wilcoxon signed rank test was used to assess the statistical significance of the obtained results. No statistically significant difference was observed between the stiffness of the toe-region (e <= ê) obtained from Thiel embalmed and fresh frozen specimens (p-value = 0.249). In the contrary, the stiffness of linear elastic region (e > ê) was significantly different between both groups (p-value = 0.046 – see Figure 2). An average, the Thiel embalmed specimens displayed a 36% higher stiffness compared to the fresh frozen specimens. The latter contrasts the findings of other studies reported in literature, which report a decrease of the stiffness following Thiel embalming. To the authors’ opinion, this discrepancy could either be attributed to a difference in testing protocol (embalming time, donor factors, …) or tissue perfusion kinetics (Achilles tendon is relatively massive). In conclusion, this study has demonstrated that Thiel embalming significantly alters the biomechanical properties of tendons. Specimens that underwent Thiel embalming should therefore not be considered for determining input parameters for advanced numerical models