Introduction

Peroneal tendon subluxation & dislocation is a rare phenomenon. It is a commonly misdiagnosed cause of lateral ankle pain and instability.

The attitudes of orthopaedic surgeons regarding radiology reporting is not well-described in the literature. We surveyed Orthopaedic Surgeons in Australia and New Zealand to assess if they routinely review formal radiology reports. An anonymized, 14 question online survey was distributed to consultant surgeons of the Australian and New Zealand Orthopaedic Associations (AOA, NZOA). Two hundred respondents completed the survey (Total number of Fellows: 283 NZOA, 1185 AOA). 18.5% of respondents always reviewed the formal Radiology report, 44.5% most of the time, 35% sometimes and 2% never. By imaging modality, MRI reports were the most frequently reviewed (92%), followed by ultrasound (74%) and nuclear medicine (63%). Only 10% of surgeons consulted formal reports for plain radiography. 55% of surgeons were still likely to disagree with the MRI report, followed by 46% for plain radiography. In cases of disagreement, only 21% of surgeons would always contact the reporting radiologist. The majority of Surgeons (85.5%) think there should be more collaboration between the disciplines, although only 50.5% had regular attendance of a Radiologist at their departmental audit. This survey reveals that the majority of orthopaedic surgeons are not routinely reading radiology reports. This points towards a need for further interdisciplinary collaboration. To our knowledge, this is the first survey directly assessing attitudes of orthopaedic surgeons towards radiology reports

Introduction. Limb deformity is usually assessed clinically assisted by long leg alignment radiographs and further imaging modalities (MRI and CT). Often decisions are made based on static imaging and simple gait interpretation in clinic. We have assessed the value of gait lab analysis in surgical decision making comparing surgical planning pre and post gait lab assessment. Materials & Methods. Patients were identified from the local limb reconstruction database. Patients were reviewed in the outpatient clinic and long leg alignment radiographs and a CT rotational limb profile were performed. A surgical plan was formulated and documented. All patients then underwent a formal gait lab analysis. The gait lab recommendations were then compared to the initial plan. Results. Twelve patients (8 female) with mean age of 14 (range 12–16) were identified. Nine were developmental torsional malalignments, one arthrogryposis, one hemiparesis secondary to spinal tumour resection and one syndromic limb deficiency. The gait lab recommended conservative management in four patients and agreed with eight surgical plans with one osteotomy level changing. Five patients are post-operative: two bilateral distal tibial osteotomies, two de-rotational femoral osteotomy with de-rotational tibial osteotomies and one bilateral femoral de-rotational osteotomies. Conclusions. Limb deformity correction is major surgery with long rehabilitation and recovery period. Gait lab analysis can identify who would benefit from conservative management rather than surgery with our study showing changes to surgical planning in one third of patients. The gait lab analysis helps to identify patients with functional and neuromuscular imbalances where correcting the bony anatomy may not actually benefit the patient

Long femoral nails for neck of femur fractures and prophylactic fixation have a risk of anterior cortex perforation. Previous studies have demonstrated the radius of curvature (ROC) of a femoral nail influencing the finishing point of a nail and the risk of anterior cortex perforation. This study aims to calculate a patients femoral ROC using preoperative XR and CT and therefore nail finishing position. We conducted a retrospective study review of patients with long femoral cephalomedullary nailing for proximal femur fractures (OTA/AO 31(A) and OTA/AO 32) or impending pathological fractures at a level 1 trauma centre between January 1, 2015 and December 31, 2020 with both full length lateral X-ray and CT imaging. Femoral ROC was calculated on both imaging modalities. Outcomes measured including nail finishing position, anterior cortex encroachment and impingement. The mean femoral ROC was 1026mm on CT and 1244mm on XR. CT femoral ROC strongly correlated with nail finishing point with a spearmans coefficient of 0.77. Additionally, femurs with a ROC <1000mm were associated with a higher risk of anterior encroachment (OR 6.12) and femurs with a ROC <900mm were associated with a higher risk of anterior cortex impingement (OR 6.47). To our knowledge this is the first study to compare a measured femoral ROC to nail finishing position. The use of CT to measure femoral ROC and to a lesser extent XR was able to predict both nail finishing position and risk of anterior cortex encroachment. Preoperative XRs and CTs were able to identify patients with a small femoral ROC. This predicted patients at risk of anterior cortex impingement, anterior cortex encroachment and nail finishing position. We may be able to select femoral nails that resemble the native femoral ROC and mitigate the risk of anterior cortex perforation

Aim. Magnetic resonance imaging (MRI) and 2-[. 18. F]-fluoro-2-deoxy-D-glucose (. 18. F-FDG) Positron Emission Tomography, paired with Computed Tomography (PET/CT) are two indicated advanced imaging modalities in the complicated diagnostic work-up of osteomyelitis. PET/MRI is a relatively novel hybrid modality with suggested applications in musculoskeletal infection imaging. The goal of this study was to assess the value of hybrid . 18. F-FDG PET/MRI for chronic osteomyelitis diagnosis and surgical planning. Method. Five suspected chronic osteomyelitis patients underwent a prospective . 18. F-FDG single-injection/dual-imaging protocol with hybrid PET/CT and hybrid PET/MR. Diagnosis and relevant clinical features for the surgeon planning treatment were compared. Subsequently, 36 patients with . 18. F-FDG PET/MRI scans for suspected osteomyelitis were analysed retrospectively. Sensitivity, specificity, and accuracy were determined with the clinical assessment as the ground truth. Standardized uptake values (SUV) were measured and analysed by means of receiver operating characteristics (ROC). Results. The consensus diagnosis was identical for PET/CT and PET/MRI in the prospective cases, with PET/CT missing one clinical feature. The retrospective analysis yielded a sensitivity, specificity, and accuracy of 78%, 100%, and 86% respectively. Area under the ROC curve was .736, .755, and.769 for the SUVmax, target to background ratio, and SUVmax_ratio respectively. These results are in the same range and not statistically different compared to diagnostic value for . 18. F-FDG PET/CT imaging of osteomyelitis in literature. Conclusions. Based on our qualitative comparison, reduced radiation dose, and the diagnostic value that was found, the authors propose . 18. F-FDG PET/MRI as an alternative to . 18. F-FDG PET/CT in osteomyelitis diagnosis, if available

16 to 34% of the population suffer from shoulder pain, the most common cause being rotator cuff tears. NICE guidance recommends using ultrasound scan (USS) or MRI to assess these patients, but does not specify which is preferable. This study assesses the accuracy of USS and MRI in rotator cuff tears in a DGH, to establish the most appropriate imaging modality. Patients who had at least two of shoulder ultrasound, MRI or arthroscopy within a seven month period (n=55) were included in this retrospective study. Sensitivity, Specificity, Positive Predictive Value (PPV) and Negative Predictive Value (NPV) were calculated using arthroscopy as the true result, and kappa coefficients calculated for each pairing. 59 comparisons were made in total. Sensitivity for MRI in full supraspinatus tears was 0.83, and for USS 0.75. Specificity for MRI in these tears was 0.75, and for USS 0.83. Values were much lower in other tears, which occurred less frequently. USS and MRI completely agreed with each other 61.3% of the time. Both modalities were only completely accurate 50% of the time. Kappa coefficient between arthroscopy and MRI for supraspinatus tears was 0.658, and for USS was 0.615. There was no statistical difference between MRI and USS sensitivity or specificity (p=1), suggesting that one modality cannot be recommended over the other for full supraspinatus tears. They also do not tend to corroborate one another, suggesting that there is no benefit from doing both scans. Further research is needed to see how both modalities can be improved to increase their accuracy

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

Introduction. The number of complex revision total hip arthroplasties (THA) is predicted to rise. The identification of acetabular bone defects prior to revision THA has important implications on technique and complexity of acetabular reconstruction. Paprosky et al. proposed a classification system including 3 main types with up to 3 subtypes focused on the integrity of the superior rim of the acetabulum and medial wall. However, the classification system is complex and its reliability has been questioned. The purpose of this study was to evaluate the effectiveness of different radiologic imaging modalities (plain radiographs, 2-D CT, 3-D CT reconstructions) in classifying acetabular defects in revision hip arthroplasty cases and their value of at different levels of orthopaedic training. Methods. Patients treated with revision total hip arthroplasty for acetabular bone defects between 2002–2012 were identified and 22 cases selected that had plain radiographs, 2-D CT and 3-D reconstructions available. Bone defects were classified independently by two fellowship-trained adult reconstruction surgeons. Representative sections were chosen and compiled into a timed presentation. Thirty-five residents from PGY-1 to PGY-5 and 4 attending orthopaedic surgeons were recruited for this study and received a 15-minute introduction to the classification system. Chi square analysis was utilized to examine the influence of image modality and level of training on the correct classification of acetabular bone loss using the Paprosky classification system with alpha=0.05. Results. The correct classification regardless of imaging of PGY levels was 30%. The level of training did not influence the ability to classify an acetabular defect (p=0.918). Correct classification was significantly influenced by the imaging used. Using x-ray led to 37% correctly identified defects, CT scans to 33% and 3D modeling to 30% of correct answers (p<0.001). For Class 1 defects, x-ray imaging had significantly higher number of correct classification (93%) compared to CT scans (67%) and 3D modeling (31%, p<0.001). Similarly, 2A defects were classified correctly with higher frequency on x-ray (49%) compared to CT scans (36%) or 3D modeling (15%, p=0.007). For type 2B, 2C, 3A and 3B defects, the type of imaging did not influence the frequency of correct answer. The level of training did not influence the frequency of correct classification regardless of the type of defect (p<0.05). However, there was a significant difference based on the defect type (p<0.001). Regardless of level of training or imaging, 64% of observers recognized type 1 defects, compared to only 16% correct recognition of 3B defects. Discussion. In the current study using different image modalities, residents regardless of the level of training were only able to classify 30% of defects correctly using the Paprosky classification system of acetabular defects. Using plain x-rays led to an increased number of correct classification, while regular CT scan and 3D CT reconstructions did not improve accuracy. The cost for advanced imaging when using this classification may not be justified. The Paprosky classification system of acetabular defects can be used for treatment decisions; however, it is complex and residents may require increased education in its use and identification of defects

Aim. Diagnosing a prosthetic joint infection (PJI) can be difficult. Several imaging modalities are available, but the choice which technique to use is often based on local expertise, availability and costs. Some centers prefer to use 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) as first imaging modality of choice, but due to a lack of accurate interpretation criteria, FDG-PET is currently not routinely applied for diagnosing PJI. With FDG-PET it is difficult to differentiate between FDG uptake due to reactive inflammation and uptake due to an infection. Since the physiological uptake pattern around a joint prosthesis is not fully elucidated, the aim of this study was to determine: i) the FDG uptake pattern in non-infected total hip prostheses and, ii) to evaluate whether there is a difference in uptake between cemented and non-cemented prostheses. Method. Patients with a primary total hip arthroplasty (1995–2016) without clinical signs of an infection that underwent a FDG-PET for another indication (mainly suspicion of malignancy) were included and retrospectively analysed. Patients in whom the prosthesis was implanted < 6 months prior to FDG-PET were excluded, to avoid post-surgical effects. Scans were visually and quantitatively analysed. Quantitative analysis was performed by calculating maximum and peak standardized uptake values (SUVmax and SUVpeak) by volume of interests (VOIs) at eight different locations around the prosthesis, from which the mean SUV was calculated. SUV was standardized by the liver SUV that was taken as background. Results. A total of 52 scans from 30 patients were analysed, with a median age of the prosthesis of 5.9 years (range 0.5–19.8). Most scans (87%) showed a diffuse uptake pattern around the prosthesis. The standardized median SUVmax and SUVpeak were 0.89 (IQR 0.78–1.16) and 0.64 (IQR=0.55–0.89), respectively. There was a difference in FDG uptake between the cemented (median SUVmax 0.85, IQR=0.77–1.04) and the uncemented prostheses (median SUVmax 1.01, IQR=0.84–2.01) (p=0.026). In uncemented prostheses, there was a positive correlation in time between the age of the prosthesis and the FDG uptake (rs=0.66, p=0.004). This observation was not found in cemented prostheses (rs=0.01, p=0.96). Conclusions. Non-infected total hip prostheses mostly show a diffuse FDG pattern around the prosthesis with a higher FDG uptake in uncemented compared to cemented prostheses. In uncemented prostheses, FDG uptake increases with the age of the implant. These findings may aid in the development of accurate interpretation criteria to better differentiate between inflammation and infection in patients with a prosthetic joint

Aim. To demonstrate the use of indium-111 white-cell labelled SPECT CT (In111-WC-SPECT-CT) in bone infection. Method. This novel imaging modality is useful in bone infection. We present three cases of complex osteomyelitis to illustrate this. All were imaged with conventional modalities, but conclusive diagnosis could not be achieved. In111-WC-SPECT-CT was used to provide the definitive imaging that allowed successful treatment. Results. Case 1- A 29 y/o Male with spina bifida presented with chronic calcaneal osteomyelitis. Previous treatment included debridement, but recurrent infection ensued. MRI showed widespread changes consistent with infection throughout the calcaneus and a below knee amputation was planned. In111-WC-SPECT-CT (Figure 1) showed a distinct localised nidus of infection. A targeted sequestrectomy was performed and the patient has been infection free for four years. He was spared the amputation. Case-2- A 73 y/o male presented with a radiation induced colo-cutaneous fistula and pelvic chronic osteomyelitis. Surgical treatment included multiple debridements and sequestrectomy. He re-presented pain with pain in his pelvis six months later. MRI was performed and oedema seen in the bone. This was presumed to be infection and further surgery was planned. An In111-WC-SPECT-CT was then performed and confirmed no residual bone infection. The patient was spared surgery. Case-3- A 38 y/o female was involved in an RTA 6 months prior to presentation. She underwent fixation of her tibia with skin grafting for an open fracture. There was clinical suspicion of deep infection. The metalwork made MRI difficult to interpret. An In111-WCC-SPECT-CT confirmed infection around the metal screw and this evidence instigated a prolonged course of antibiotics to suppress the infection. The screw will be removed after the fracture heals. Conclusions. In-111-WC-SPECT-CT is an emerging imaging modality. We present three cases of complex bone and joint infection; where this imaging has altered the course of treatment

Introduction. There are conflicting views when assessing the best imaging modality by which to assess long leg alignment pre and post operatively for patients’ receiving primary total hip replacements. It has been a long standing standard that long-leg radiographs are used for measuring and interpreting alignment of the lower limb, but recently it has been suggested that CT imaging may be a better option for this assessment. Methods. Patients awaiting total knee replacement surgeries were invited to participate in this clinical trial. 120 participants’ consented and completed both pre and post-operative long-leg radiographs, and lower limb CT scans. Long leg radiographs were analysed and measured by senior orthopaedic surgeons pre and post-operatively, while CT scans were analysed using the perth protocol method by trained radiologists. Mechanical alignment of the lower limb was calculated using both imaging modalities, the CT “scout” scan was used for the measurement of the mechanical alignment. Pre-operatively the patients had their imaging performed between 1 year and 1 week pre-operatively, and following surgery their imaging was standardised to 6 months post-operatively. For long leg radiographs, patients were asked to stand with their feet shoulder width apart and toes forward facing (on occasion deformities would not allow for this stance, and they were asked to adopt this stance to the best of their ability). Result. The results were analysed using pearsons correlation tests, correlation was shown to be good between the mechanical alignment measurements taken from long leg radiographs, and also from CT scout scans. Preliminary results have shown that correlation between the two modalities is 0.7, displaying a good level of correlation. Interobserver and intra observer analysis of the mechanical alignment taken from long leg radiographs is shown to be excellent with preliminary correlation being 0.9. Conclusion. The correlation results show that CT scans could be using in place of long leg radiographs, and this could assist in measuring the alignment of patients with deformities rendering them unable to stand. Radiation dose has been a main focus of many papers reviewing this correlation previously, but as the mechanical alignment does not require an investigational CT scan to be performed, but only a scout CT scan, the radiation dose is quite comparable to that of a long leg radiograph. CT scan have the additional ability of being able to place the whole image of the leg onto one screen, whereas x-ray of the entire leg required the merging of three different cassettes. This leads to additional human error with the aligning of these cassettes by the radiographer prior to taking the image, and following exposure. CT scans should be considered for measuring the alignment of the lower limb prior to and after total knee replacement

The radiographic analysis of over 5000 metal on metal (MoM) hips using Ein Bild Roentgen Analyse (EBRA) software have been recently published in an attempt to determine the influence of cup orientation on bearing function. The validation of this software relies one study, conducted in a phantom pelvis without a femoral head in situ. Three dimensional computed tomographic (3D-CT) has been shown to be more accurate for hip and knee arthroplasty than plain radiographs for measurements of component orientation and position. The accuracy of EBRA when compared to 3D-CT for MoM hips specifically is unclear. We measured the cup orientation of 96 large diameter MoM hips using EBRA analysis of plain radiographs and compared this to 3D-CT. All measurements were made using the radiographic definition of cup orientation. The mean difference in version between the two imaging modalities was 8°; with wide limits of agreement of −21.2° and +5.6°. Three retroverted cups were not detected by EBRA. The mean difference in inclination values was 0.3°, but there was up to 9°difference between imaging modalities. When measured by 3D CT, 64% of hips were within a 10° safe zone around 45° inclination and 20° version, compared to only 24% when measured by EBRA (Fishers Exact test, p< 0.0001). The measurement of cup orientation of MoM hips using EBRA software is insufficiently accurate, particularly for the assessment of cup version. The cup rim is obscured by the large diameter femoral head on plain radiographs. Research studies using EBRA analysis for version have limited value if accuracy of more than 20 degrees is required to draw conclusions. This software may not be suitable to measure the performance of a device or surgeon. The limitations of EBRA can be overcome, if 3D-CT with an extended Hounsfield scale for data capture is used

Treatment for osteoarthritis (OA) has traditionally focused on joint replacement for end-stage disease. An increasing number of surgical and pharmaceutical strategies for disease prevention have now been proposed. However, these require the ability to identify OA at a stage when it is potentially reversible, and detect small changes in cartilage structure and function to enable treatment efficacy to be evaluated within an acceptable timeframe. This has not been possible using conventional imaging techniques but recent advances in musculoskeletal imaging have been significant. In this review we discuss the role of different imaging modalities in the diagnosis of the earliest changes of OA. The increasing number of MRI sequences that are able to non-invasively detect biochemical changes in cartilage that precede structural damage may offer a great advance in the diagnosis and treatment of this debilitating condition. Cite this article: Bone Joint J 2013;95-B:738–46

Image guided surgery (IGS), or “Navigation,” is now widely used in many areas of surgery including arthroplasty. However, the options for establishing, in real time, the veracity of the navigation information are limited. Manufacturers recommend registering with a “prominent anatomical feature” to confirm accurate navigation is being presented. In their fine print, they warrant the accuracy proximate to the navigation array attached to the body. In multi-level spine surgery where it is most sorely needed, this limits the warrants to the vertebra of reference array attachment. In arthroplasty surgery, the accuracy of the system can be erroneous through technical errors and a delay may occur prior to verification of such innacuracy. In response to this situation surgeons have taken to using K-wires, FaxMax screws and a variety of other “Fiducial Markers”, but these were not specifically designed for this purpose and in many ways are inadequate for the task of verification of navigation accuracy. We have developed a fiducial marker that is designed to address these unmet needs. The Precision Screw is clearly visible on imaging modalities and the central registration point is identifiable at any angle of viewing, with accuracy of fractions of a millimeter. It does not interfere with surgery, being low profile and securely fixed to bone. Finally, in use, it is secure in capturing the navigation probe so that the surgeon does not need to focus on keeping the probe located while reviewing the navigation data. We believe these features make this a useful and worthwhile addition to IGS

Anteroposterior (AP) pelvic radiographs are the standard tool used for pre-operative planning and post-operative evaluation during total hip arthroplasty (THA). The accuracy of this imaging modality is, however, limited by errors in pelvic orientation and image distortion. Pelvic obliquity is corrected for by orienting measurements to a reference line such as the interteardrop line or the interischial line, while several methods for correcting for pelvic tilt have been suggested, with varying levels of success. To date, no reliable method for correcting for pelvic rotation on pelvic imaging is available. The purpose of this study was to evaluate a novel method for correcting pelvic rotation on a standard anteroposterior (AP) radiographs. Computed tomography (CT) scans from 10 male cadavers and 10 female THA patients were segmented using 3D Slicer and used to create 3D renderings for each pelvis. Synthetic AP radiographs were subsequently created from the 3D renderings, using XRaySim. For each pelvis, images representing pelvic rotation of 30° left to 30° right, at 5° increments were created. Four unique parameters based on pelvic landmarks were used to develop the correction method: i) the horizontal distance from the upper edge of the pubic symphysis to the sacroiliac joint midline (PSSI), ii) the ratio of the horizontal distances from the upper edge of the pubic symphysis to the outer lateral border of both obturator foramina (PSOF), iii) the width ratio of the obturator foramina (OFW) and iv) the ratio of the horizontal distance from each anterior superior iliac spine to the sacroiliac joint midline (ASISSI). The relationships between the chosen parameters and pelvic rotation were investigated using a series of 260 (13 per pelvis) synthetic AP radiographs. Male and female correction equations were generated from the observed relationships. Validation of the equations was done using a different set of 50 synthetic radiographs with known degrees of rotation. In males, the PSSI parameter was most reliable in measuring pelvic rotation. In females, PSOF was most reliable. A high correlation was noted between calculated and true rotation in both males and females (r=0.99 male, r=0.98 female). The mean difference from the male calculated rotation and true rotation value was 0.02°±1.8° while the mean difference from the female calculated rotation and true rotation value was −0.01°±1.5°. Our correction method for pelvic rotation using four pelvic parameters provides a reliable method for correcting pelvic rotation on AP radiographs. For any figures or tables, please contact authors directly

Aim. White blood cell (WBC) scintigraphy for diagnosing fracture-related infections (FRIs) has only been investigated in small patient series. Aims of this study were (1) to establish the accuracy of WBC scintigraphy for diagnosing FRIs, and (2) to investigate whether the duration of the time interval between surgery and WBC scintigraphy influences its accuracy. Method. 192 consecutive WBC scintigraphies with . 99m. Tc-HMPAO-labelled autologous leucocytes performed for suspected peripheral FRI were included. The goldstandard was based on the outcome of microbiological investigation in case of surgery, or - when these were not available - on clinical follow-up of at least six months. The discriminative ability of the imaging modalities was quantified by several measures of diagnostic accuracy. A multivariable logistic regression analysis was performed to identify predictive variables of a false-positive or false-negative WBC scintigraphy test result. Results. WBC scintigraphy had a sensitivity of 0.79, a specificity of 0.97, a positive predicting value of 0.91, a negative predicting value of 0.93 and a diagnostic accuracy of 0.92 for detecting an FRI in the peripheral skeleton. The duration of the interval between surgery and the WBC scintigraphy did not influence its diagnostic accuracy; neither did concomitant use of antibiotics or NSAIDs. There were 11 patients with a false-negative (FN) WBC scintigraphy, the majority of these patients (n = 9, 82%) suffered from an infected nonunion. Four patients had a false-positive (FP) WBC scintigraphy. Conclusions. WBC scintigraphy showed a high diagnostic accuracy (0.92) for detecting FRIs in the peripheral skeleton. Duration of the time interval between surgery for the initial injury and the WBC did not influence the results which indicate that WBC scintigraphy is accurate shortly after surgery

Introduction. At present, orthopaedic surgeons utilize either CT, MRI or X-ray for imaging a joint. Unfortunately, CT and MRI are quite expensive, non weight-bearing and the orthopaedic surgeon does not receive revenue for these procedures. Although x-rays are cheaper, similar to CT scans, patients incur radiation. Also, all three of these imaging modalities are static. More recently, a new ultrasound technology has been developed that will allow a surgeon to image their patients in 3D. The objective of this study is to highlight the new opportunity for orthopaedic surgeons to use 3D ultrasound as alternative to CT, MRI and X-rays. Methods. The 3D reconstruction process utilizes statistical shape atlases in conjunction with the ultrasound RF data to build the patient anatomy in real-time. The ultrasound RF signals are acquired using a linear transducer. Raw RF data is then extracted across each scan line. The transducer is tracked using a 3D tracking system. The location and orientation for each scan line is calculated using the tracking data and known position of the tracker relative to the signal. For each scan line, a detection algorithm extracts the location on the signal of the bone boundary, if any exists. Throughout the scan process, a 3D point cloud is created for each detected bone signal. Using a statistical bone atlas for each anatomy, the patient specific surface is reconstruction by optimizing the geometry to match the point cloud. Missing regions are interpolated from the bone atlas. To validate reconstructed models output models are then compared to models generated from 3D imaging, including CT and MRI. Results. 3D ultrasound, which now has FDA approval in the United States, is presently available for an orthopaedic surgeon to use. Error analyses have been conducted in comparison to MRI and CT scans and revealed that 3D ultrasound has a similar accuracy of less than 1.0 mm in the creation of a 3D bone and soft-tissues. Unlike CT and MRI scans that take in excess of 2–3 weeks to create human bones, 3D ultrasound creates bones in 4–6 minutes. Once the bones are created, the surgeon can assess bone quality, ligament and cartilage conditions, assess osteophytes, fractures and guide needles into the 3D joint space. The creation of 3D bones has been accurately assessed for the spine, shoulder, knee, hip and ankle joints. A 3D joint pre-operative planning module has also been developed for a surgeon to size and position components before surgery. Discussion. 3D ultrasound is an exciting new imaging technology available for orthopaedic surgeons to use in their practice. Existing CPT codes are readily available for 3D ultrasound procedures. A surgeon can now evaluate and diagnose bone and soft- tissue conditions, in 3D, using ultrasound, which is safer and is an easier procedure compared to CT, MRI and X-rays. This new ultrasound technology is a highly accurate imaging technique that will allow a surgeon to diagnose bone and soft-tissue concerns in 3D, under weight-bearing, dynamic conditions and guide needle injections to correct location, in 3D

While advances in laboratory and imaging modalities facilitate the diagnosis of periprosthetic joint infection (PJI), clinical suspicion and a thorough history and physical remain the basis of evaluation. If clinical suspicion is high, the evaluation should be more vigorous, and vice versa. The erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are inexpensive as well as ubiquitous, and should be obtained as a preliminary screening tool. These tests have been found to be cost-effective and highly sensitive. If both tests are negative, there is a low risk of periprosthetic joint infection (i.e., good negative predictive value). Positive results on both tests, in contrast, are not as specific but again raise suspicion. When either the ESR or CRP is elevated, or if the clinical suspicion for infection is high, aspiration of the knee joint is suggested. Synovial fluid should be sent for a synovial fluid white blood cell count (WBC), differential and culture. Given the ability to get three data points from one intervention, arthrocentesis, is the best single maneuver the physician can perform to rule in or out PJI. The synovial fluid WBC count has demonstrated in multiple studies excellent specificity and sensitivity in the diagnosis of infection. Based on multiple recent studies, the proceedings of the International Consensus on PJI recommend cut-offs for the synovial fluid WBC count as >3000 cells/mL and > 80% neutrophils for the differential. Synovial fluid biomarkers represent an expanding area of clinical interests based on the unique cascade of gene expression that occurs in white blood cells in response to pathogens. Deirmegian et al. described the unique gene expression and biomarker production by neutrophils in response to bacteria that are detectable in synovial fluid. Specifically, alpha-defensin is one such antimicrobial peptide. Along with synovial CRP, alpha-defensin can be measured in a currently commercially-available immunoassays. The diagnosis of PJI can be difficult to make in spite of the variety of tests available. That being said, the diagnosis is easily made in our experience in 90% of patients by getting an ESR and CRP followed by selective aspiration of the joint if these values are elevated or if the clinical suspicion is high. Synovial fluid obtained should be sent for a synovial fluid WBC count, differential and cultures

Aim. Autologous-labeled leukocytes combined with sulfur colloid bone marrow scan is the current imaging modality of choice for diagnosing prosthetic joint infection (PJI). Although this technique is reliable, in-vitro leukocyte labeling raises technical difficulties that limit its widespread use and sulfur colloid is increasingly difficult to obtain. Therefore, valid alternatives are needed. The purpose of our study was to determine the clinical value of 99mTc-sulesomab combined with 99mTc-colloidal rhenium sulphide (nanocolloid) bone marrow imaging in the diagnosis of infection in painful total joint arthroplasties. Materials and methods. A retrospective study was conducted on a cohort of 53 patients with painful hip or knee prostheses that underwent 99mTc-sulesomab and 99mTc-nanocolloids sequentially, between January 2008 and December 2016. The combined images were interpreted as positive for infection when there was activity on the sulesomab scan without corresponding activity on the bone marrow scan. The final diagnosis was made with microbiological findings or by clinical follow up of at least 12 months. Results. There were 49 total knee and 4 total hip replacements. Forty of them were women, with an average age of 65 years. Infections were diagnosed in 5 of the 53 patients. An isolated 99mTc-sulesomab scan shows 100% sensitivity but only 29.4% specificity. Combining it with a 99mTc-nanocolloid bone marrow scan, the overall sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 100%, 95.8%, 81.4%, 100% and 96.2% respectively. Conclusion. 99mTc-sulesomab combined with 99mTc-nanocolloid showed to be a useful method for diagnosing prosthetic joint infections. These technically simpler and ready-to-use products may be an alternative to autologous-labeled leukocytes/sulfur colloid marrow scan, although it needs validation at a larger scale

The meniscus is at the cornerstone of knee joint function, imparting stability and ensuring shock absorption, load transmission, and stress distribution within the knee joint. However, it is very vulnerable to injury and age-related degeneration. Meniscal tears are reported as the most common pathology of the knee with a mean annual incidence of 66 per 100,000. Knee osteoarthritis progresses more rapidly in the absence of a functional meniscus. Historically, tears extending to the avascular inner portion of the meniscus (white-white zone, “WW”), such as radial tears were considered as untreatable and were often resected, due to the lack of vascularity in the WW zone. Perfusion-based anatomical studies performed on cadaveric menisci in the 1980s shaped the current dogma that human meniscus has poor regenerative capacity, partly due to limited blood supply that only reaches 10 to 25% of the meniscus, commonly referred to as red-red zone (“RR”). Previous studies, including those utilizing animal models have shown mobilization of Mesenchymal Stem Cells (MSCs) upon injury into the WW zone, and successful MSC recruitment when administered externally to the injury site. We and others have recently reported positive outcomes of repaired tears in the inner zone of patients. We hypothesized that the “avascular” white-white zone of the meniscus possesses regenerative capacity due to a resident stem/progenitor cell population. Further, we sought to redefine the presence of microvessels in all meniscal zones using advanced stereology and imaging modalities. Fifteen menisci from fresh human cadaveric knees (mean age: 21.53±6.53 years) without evidence of previous injury were obtained from two tissue banks (JRF, Centennial, CO) and Biosource Medical (Lakeland, FL) and utilized for this study. The use of cadaveric specimens for research purposes was approved by the institutional review board. Tibial plateaus were dissected to harvest medial and lateral menisci along their entire length. The RR, red-white (RW) and WW zones were dissected and separated into three thirds from the inner aspect to the marginal border of the meniscus and their wet weights recorded (Fig.1A). Meniscus tissue cellular content in each zone was obtained from dissociation of meniscus tissue using 0.02% w/v pronase (Millipore) for 1h at 37oC, followed by 18h 0.02% w/v collagenase II (Worthington) at 37oC with shaking. Isolated cells were characterized immediately after harvest using flow cytometry with antibodies against MSCs surface markers (CD105, CD90, CD44 and CD29) as well as respective isotype controls. Further, meniscal cells were cultured and split twice when confluence was reached, characterized at P2 and compared to bone marrow-derived MSCs (BM-MSCs) using the same markers. Self-renewal of cells was assessed using colony forming unit (CFU) assay. Differentiation assays were performed to assess whether colony-forming cells retained multilineage potential. For morphological examination of bigger vessels, samples were fixed in 10% formalin for 1 week, paraffin embedded, sectioned (4 μm thick) and stained with H&E and Masson's trichrome. Presence of microvessels was assessed by CD31 immunofluorescence staining. Further, menisci were cleared using the uDisco protocol labeled with the TO-PRO®-3 stain, a fluorescent dye that stains cell nuclei and imaged using light-sheet microscopy. All continuous data are presented as mean ±standard deviation. Non-repeated measures analysis of variance (ANOVA) and Tukey-Kramer HSD post hoc analysis were performed on sample means for continuous variables. Statistical significance was set at p < 0 .05. Menisci were successfully cleared using a modified uDISCO procedure, imaged and analyzed for total cell density. As expected, bigger vessels were observed in RR but not in WW. However, immunofluorescent staining for CD31 showed a subset of CD31+endothelial cells present in the WW zone, indicating the presence of small vessels, most likely capillaries. In order to assess whether enzymatic digestion had a differential result depending on meniscus zone due to cellular content, we analyzed yields per meniscus per zone. The wet weight of different zones (WW:RW:RR) was at a ratio of ∼1:3:5 respectively, however, the ratio of cells isolated from each zone was at ∼1:4:20, indicating that RR has a denser population of mononuclear cells. However, the difference between all zones in cell yields was not significant. The clonogenic potential of isolated cells was shown to be non-significantly different between the three zones. Differentiation of isolated cells to osteogenic lineage using osteogenic media in vitroshowed no difference between the three zones. Flow cytometry analysis of cells from the three meniscal zones displayed presence of two distinct subpopulations of cells immediately after isolation. One subpopulation was positive to MSC surface markers and the other negative. Additionally, flow cytometry of cultured meniscal cells at P2 displayed that the entire cell population was CD44+CD105+CD29+CD90+, suggesting that culturing meniscal cells results in selection of stem/progenitor cells (plastic adherence). Surface marker expression analysis showed differential expression patterns between markers depending on zone. Similar fraction of cells was detected to express both MSC markers CD90 and CD105 (7–10%) and similar fraction of cells expressed both MSC markers CD29 and CD44 (1–2%) in all three zones, indicating similar density of resident stem/progenitor cells in each zone. Importantly, WW showed significantly higher expression for all four MSC markers compared to the RR zone, indicating higher relative density of stem/progenitor resident cells in the WW zone. Our results determine that CD31-expressing microvessels were present in all zones, including the WW zone, which was previously considered completely avascular. Additionally, stem/progenitor cells were shown to be present in all three zones of the menisci, including the WW zone, showcasing its regenerative potential. For any figures or tables, please contact the authors directly