Several studies have evaluated the risk of peroneal nerve (PN) injuries in all-inside lateral meniscal repair using standard knee magnetic resonance imaging (MRI) with the 30 degrees flexed knee position which is different from the knee position during actual arthroscopic lateral meniscal repair. The point of concern is “Can the risk of PN injury using standard knee MRIs be accurately determined”. To evaluate and compare the risk of PN injury in all-inside lateral meniscal repair in relation to both borders of the popliteus tendon (PT) using MRIs of the two knee positions in the same patients. Using axial MRI studies with standard knee MRIs and figure-of-4 with joint fluid dilatation actual arthroscopic lateral meniscal repair position MRIs, direct lines were drawn simulating a straight all-inside meniscal repair device from the anteromedial and anterolateral portals to the medial and lateral borders of the PT. The distance from the tip of each line to the PN was measured. If a line touched or passed the PN, a potential risk of iatrogenic injury was noted and a new line was drawn from the same portal to the border of the PN. The danger area was measured from the first line to the new direct line along the joint capsule. In 28 adult patients, the closest distances from each line to the PN in standard knee MRI images were significantly shorter than arthroscopic position MRI images (all p-values < 0.05). All danger areas assessed in the actual arthroscopic position MRIs were included within the danger areas as assessed by the standard knee MRIs. We found that the standard knee MRIs can be used to determine the risk of peroneal nerve injury in arthroscopic lateral meniscal repair, although the risks are slightly overestimated

The relationship of degeneration to symptoms has been questioned. MRI detects apparently similar disc degeneration and degenerative changes in subjects both with and without back pain. We aimed to overcome these problems by re-annotating MRIs from asymptomatic and symptomatic groups onto the same grading system. We analysed disc degeneration in pre-existing large MRI datasets. Their MRIs were all originally annotated on different scales. We re-annotated all MRIs independent of their initial grading system, using a verified, rapid automated MRI annotation system (SpineNet) which reported degeneration on the Pfirrmann (1-5) scale, and other degenerative features (herniation, endplate defects, marrow signs, spinal stenosis) as binary present/absent. We compared prevalence of degenerative features between symptomatics and asymptomatics. Pfirrmann degeneration grades in relation to age and spinal level were very similar for the two independent groups of symptomatics over all ages and spinal levels. Severe degenerative changes were significantly more prevalent in discs of symptomatics than asymptomatics in the caudal but not the rostral lumbar discs in subjects < 60 years. We found high co-existence of degenerative features in both populations. Degeneration was minimal in around 30% of symptomatics < 50 years. We confirmed age and disc level are significant in determining imaging differences between asymptomatic and symptomatic populations and should not be ignored. Automated analysis, by rapidly combining and comparing data from existing groups with MRIs and information on LBP, provides a way in which epidemiological and ‘big data’ analysis could be advanced without the expense of collecting new groups

In current practice in the UK there are three main approaches to investigating suspected scaphoid fractures not seen on initial plain film x-rays. Early MRI of all cases. Review all cases in clinic at two weeks with repeat x-rays. Hybrid model. Virtual Fracture Clinic (VFC) triage to reduce those who are seen in clinic at two weeks by:. ∘. Organising early MRI for those with high-risk presentation. ∘. Discharging those with an alternative more likely diagnosis. Our unit uses the VFC model. We aimed to evaluate its efficiency, safety, clinical outcomes and economic viability. All patients attending the emergency department with either a confirmed or suspected scaphoid fracture between March and December 2020 were included (n=305). Of these 297 were referred to the VFC: 33 had a confirmed fracture on x-ray and 264 had a suspected fracture. Of the suspected fractures reviewed in VFC 14% had an MRI organised directly owing to a high-risk presentation, 79% were brought for fracture clinic review and 17% discharged with an alternative diagnosis such as osteoarthritis. Of those subsequently reviewed in fracture clinic at two weeks: 9% were treated as scaphoid fractures (based on clinical suspicion and repeat x-rays), 17% had MRI or CT imaging organised, 5% did not attend and 69% were discharged. Overall, 17% of cases initially triaged, had further imaging – 41 MRIs and 5 CTs. MRI detected: 5% scaphoid fracture, 17% other fracture, 24% bone contusion, complete ligament tear 10%, partial ligament tear 39% and normal study 10%. The results of MRI minimally affected management. 3 patients were taken out of plaster early, 1 patient was immobilized who was not previously and no patients underwent operative management. In the following 12-month period one patient re-presented with a hand or wrist issue. This approach avoided 218 MRIs, equating to £24000 and 109 hours of scanner time. VFC triage and selective use of MRI scanning is a safe, efficient and cost-effective method for the management suspected scaphoid fractures. This can be implemented in units without the resource to MRI all suspected scaphoid fractures from the emergency department

Knee pain is common, representing a significant socioeconomic burden. Caused by a variety of pathologies, its evaluation in primary-care is challenging. Subsequently, an over-reliance on magnetic resonance imaging (MRI) exists. Prior to orthopaedic surgeon referral, many patients receive no, or incorrect, imaging. Electronic-triage (e-triage) tools represent an innovative solution to address this problem. The primary aim of this study was to ascertain whether an e-triage tool is capable of outperforming existing clinical pathways to determine the correct pre-hospital imaging based on knee pain diagnosis. Patients ≥18 years with a new presentation of knee pain were retrospectively identified. The timing and appropriateness of imaging was assessed. A symptom-based e-triage tool was developed, using the Amazon LEXbotplatform, and piloted to predict five common knee pathologies and suggest appropriate imaging. 1462 patients were identified. 17% of arthroplasty patients received an ‘unnecessary MRI’, whilst 28% of arthroscopy patients did not have a ‘necessary MRI’, thus requiring a follow-up appointment, with a mean delay of three months (SD 2.6, range 0.2-20.2). Using NHS tariffs, a wasted cost through unnecessary/necessary MRIs and subsequent follow-up appointments was estimated at £45,816. The e-triage pilot was trialled with 41 patients (mean age:58.4 years, 58.5% female). Preliminary diagnoses were available for 34 patients. Using the highest proportion of reported symptoms in the corresponding group, the e-triage tool correctly identified three of the four knee pathologies. The e-triage tool did not correctly identify anterior cruciate ligament injuries (n=3). 79.2% of participants would use the tool again. A significant number of knee pathology patients received incorrect imaging prior to their initial hospital appointment, incurring delays and unnecessary costs. A symptom-based e-triage tool was developed, with promising pilot data and user feedback. With refinement, this tool has the potential to improve wait-times and referral quality, whilst reducing costs

This study investigates the relationships between Intervertebral Disc (IVD) morphology and biomechanics using patient-specific (PS) finite element (FE) models and poromechanical simulations. 169 3D lumbar IVD shapes from the European project MySpine (FP7-269909), spanning healthy to Pfirrmann grade 4 degeneration, were obtained from MRIs. A Bayesian Coherent Point Drift algorithm aligned meshes to a previously validated structural FE mesh of the IVD. After mesh quality analyses and Hausdorff distance measurements, mechanical simulations were performed: 8 and 16 hours of sleep and daytime, respectively, applying 0.11 and 0.54 MPa of pressure on the upper cartilage endplate (CEP). Simulation results were extracted from the anterior (ATZ) and posterior regions (PTZ) and the center of the nucleus pulposus (CNP). Data mining was performed using Linear Regression, Support Vector Machine, and eXtreme Gradient Boosting techniques. Mechanical variables of interest in DD, such as pore fluid velocity (FLVEL), water content, and swelling pressure, were examined. The morphological variables of the simulated discs were used as input features. Local morphological variables significantly impacted the local mechanical response. The local disc heights, respectively in the mid (mh), anterior (ah), and posterior (ph) regions, were key factors in general. Additionally, fluid transport, reflected by FLVEL, was greatly influenced (r2 0.69) by the shape of the upper and lower cartilage endplates (CEPs). This study suggests that disc morphology affects Mechanical variables of interest in DD. Attention should be paid to the antero-posterior distribution and local effects of disc heights. Surprisingly, the CEP morphology remotely affected the fluid transport in NP volumes around mid-height, and mechanobiological implications shall be explored. In conclusion, patient-specific IVD modeling has strong potential to unravel important correlations between IVD phenotypes and local tissue regulation. Acknowledgments: European Commission: Disc4All-MSCA-2020-ITN-ETN GA: 955735; O-Health-ERC-CoG-2021-101044828

Background. The anatomy of the human body has been studied for centuries. Despite this, recent articles have announced the presence of a new knee ligament- the anterolateral ligament. It has been the subject of much discussion and media commentary. Previous anatomical studies indicate its presence, and describe its location, origin, course and insertion. Magnetic resonance imaging (MRI) is the best and most commonly used investigation to assess the ligamentous structure of the knee. To date, most MRI knee reports make no mention of the anterolateral ligament. The aim of this study was to assess for the presence of the anterolateral ligament using MRI, and to describe the structure if visualised. Methods. All right knee MRIs performed on a Siemens Magnetom Espree 1.5 Tesla scanner in Merlin Park Hospital over a 4 year period were retrospectively analysed. Patients born before 1970, or with reported abnormalities were excluded. The normal MRIs were then analysed by a consultant radiologist specialising in musculoskeletal imaging. Measurements on origin, insertion, course and length were noted. Results. 942 right knee MRIs were performed in the time period. 62 were classed as normal, and within the specified age range. 10 were randomly sampled. Of these the ligament was visible on all 10 MRIs, best viewed in the coronal plane. The average length (visible in 8/10) was 28.88mm +/− 5.14mm. The origin (visible in all 10) was 2.25mm +/− 0.39mm. The insertion (visible in 9/10) was 1.93mm +/− 0.424. The mid thickness was 1.87mm +/− 0.2mm. Conclusions. This study indicates that the ALL is a discrete, visible structure on MRI. This furthers the evidence of the presence of the ALL and also provides information that may be beneficial in future studies, and assessment of knee injuries. Level of evidence. 4

Abstract. Objectives. Back pain will be experienced by 70–85% of all people at some point in their lives and is linked with intervertebral disc (IVD) degeneration. The aim of this study was to 1) compare 3D internal strains in degenerate and non-degenerate human IVD under axial compression and 2) to investigate whether there is a correlation between strain patterns and failure locations. Methods. 9.4T MR images were obtained of ten human lumbar IVD. Five were classed as degenerate (Pfirrmann = 3.6 ± 0.3) and five were classed as non-degenerate (Pfirrmann = 2.0 ± 0.2). MR Images were acquired before applying load (unloaded), after 1 kN of axial compression, and after compression to failure using a T2-weighted RARE sequence (resolution = 90 µm). Digital Volume Correlation was then used to quantify 3D strains within the IVDs, and failure locations were determined from analysis of the failure MRIs. Results. Average of axial strains were higher (p<0.05) in the degenerate samples compared to the non-degenerate (−3.4 vs-5.2%, respectively), particularly in the posterior and lateral annulus (−6.2 vs −3.6%, and −5.6 vs −3.5%, respectively). Maximum 3D compressive strains were higher (p<0.05) in the posterior annulus and nucleus regions of the degenerate discs compared to non-degenerate (−9.8 vs −6.2%, and −7.7 vs −5.5%, respectively). In all samples peak tensile and shear strains were observed close to the endplates. All samples failed through the endplates with fractures in the nucleus region in all non-degenerate samples, and fractures in the lateral annulus regions in all degenerate samples. Conclusion. Degeneration caused significant changes to strain distributions within IVDs, particularly at the lateral and posterior AF regions. A shift from endplate failure in the nucleus to the annulus region was observed which was also seen in peak axial internal strains demonstrating a possible correlation between internal IVD strains, and endplate failure locations. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Osteochondral lesions (OCLs) of the talus are a challenging and increasingly recognized problem in chronic ankle pain. Many novel techniques exist to attempt to treat this challenging entity. Difficulties associated with treating OCLs include lesion location, size, chronicity and problems associated with potential graft harvest sites. Matrix associated stem cell transplantation (MAST) is one such treatment described for larger lesions >15mm. 2. or failed alternative therapies. This cohort study describes a 5 year review of the outcomes of talar lesions treated with MAST. A review of all patients treated with MAST by a single surgeon was conducted. Pre-operative radiographs, MRIs and FAOS outcome questionnaire scores were conducted. Intraoperative classification was conducted to correlate with imaging. Post-operative outcomes included FAOS scores, return to sport, revision surgery/failure of treatment and progression to arthritis/fusion surgery. 32 patients were identified in this cohort. There were 10 females, 22 males, with an average age of 35. 01. 73% had returned and continued playing active sport. 23 patients underwent MAST in the setting of a failed previous operative attempt, with just 9 having MAST as a first option. 9 patients out of 32 had a further procedure. Two patients had a further treatment directed at their OCL. Two patients had a fusion, 2 had a cheilectomy at > 4 years for impingement, one had a debridement of their anterolateral gutter, one had debridement for arthrofibrosis, one patient had a re alignment calcaneal osteotomy with debridement of their posterior tibial tendon. MAST has demonstrated positive results in lesions which prove challenging to treat, even in a “failed microfracture” cohort

Patellar tendinosis (PT) is common and can result in prolonged disability, especially in jumping athletes. Recently developed ultra-short-echo (UTE) MRI sequences allow for quantitative evaluation of tendon biostructure with T2* relaxometry. This study evaluated the relationships between changes over time (COT) in quantitative T2*-metrics, qualitative PT grades, and patient reported symptoms within 10 male basketball players from a single collegiate basketball team. All subjects completed weekly VISA-P symptomology questionnaires over the basketball season. Bilateral 3-Tesla MRIs (GE Healthcare) were obtained at pre- and post-season study visits. High-resolution, PD-weighted, FSE sequences were used to qualitatively grade PT. Quantitative T2*-metrics were evaluated using high-resolution, 3D, multi-echo, UTE-MRI sequences. Bilinear exponential fits of SI to corresponding echo time were used to calculate T2*-metrics. All qualitative and quantitative evaluations were region specific (proximal, middle, distal). Linear mixed effects models assessed associations of side and region with T2*-metrics. Spearman correlations evaluated relationships between outcome measures. Within and between study visits, significant side-to-side differences in T2*-metrics were found and were significantly impacted by leg dominance (p<0.05). Pre-season T2*-metrics correlated with COT in T2*-metrics, COT in T2*-metrics correlated with COT in qualitative PT grades, and post-season T2*-metrics correlated with max changes in VISA-P scores (ρ≥0.64). Quantitative T2*-metrics can detect PT and may be capable of predicting the onset of pathology. T2*-metrics could benefit the clinical management of PT: it is sensitive to changes in pathologic severity over time, and therefore can serve as a quantitative metric to guide treatment and evaluate intervention efficacy

Trochlear geometry of modern femoral implants is designed for mechanical alignment (MA) technique for TKA. The biomechanical goal is to create a proximalised and more valgus trochlea to better capture the patella and optimize tracking. In contrast, Kinematic alignment (KA) technique for TKA respects the integrity of the soft tissue envelope and therefore aims to restore native articular surfaces, either femoro-tibial or femoro-patellar. Consequently, it is possible that current implant designs are not suitable for restoring patient specific trochlea anatomy when they are implanted using the kinematic technique, this could cause patellar complications, either anterior knee pain, instability or accelerated wear or loosening. The aim of our study is therefore to explore the extent to which native trochlear geometry is restored when the Persona. ®. implant (Zimmer, Warsaw, USA) is kinematically aligned. A retrospective study of a cohort of 15 patients with KA-TKA was performed with the Persona. ®. prosthesis (Zimmer, Warsaw, USA). Preoperative knee MRIs and postoperative knee CTs were segmented to create 3D femoral models. MRI and CT segmentation used Materialise Mimics and Acrobot Modeller software, respectively. Persona. ®. implants were laser scanned to generate 3D implant models. Those implant models have been overlaid on the 3D femoral implant model (generated via segmentation of postoperative CTs) to replicate, in silico, the alignment of the implant on the post-operative bone and to reproduce in the computer models the features of the implant lost due to CT metal artefacts. 3D models generated from post-operative CT and pre-operative MRI were registered to the same coordinate geometry. A custom written planner was used to align the implant, as located on the CT, onto the pre-operative MRI based model. In house software enabled a comparison of trochlea parameters between the native trochlea and the performed prosthetic trochlea. Parameters assessed included 3D trochlear axis and anteroposterior offset from medial facet, central groove, and lateral facet. Sulcus angle at 30% and 40% flexion was also measured. Inter and intra observer measurement variabilities have been assessed. Varus-valgus rotation between the native and prosthetic trochleae was significantly different (p<0.001), with the prosthetic trochlear groove being on average 7.9 degrees more valgus. Medial and lateral facets and trochlear groove were significantly understuffed (3 to 6mm) postoperatively in the proximal two thirds of the trochlear, with greatest understuffing for the lateral facet (p<0.05). The mean medio-lateral translation and internal-external rotation of the groove and the sulcus angle showed no statistical differences, pre and postoperatively. Kinematic alignment of Persona. ®. implants poorly restores native trochlear geometry. Its clinical impact remains to be defined

BACKGROUND. Since 1996, the Scottish Hip Fracture Audit (SHFA) group have published reports on the outcomes of patients with hip fractures. In the 2008 report, the group outlined the target standard that “98% of medically fit patients who have sustained a hip fracture should be operated on within 24 hours of ‘safe operating time’ (i.e. between 8 am and 8pm, seven days a week).”. 1. . AIM. We aim to investigate the compliance of our unit to the SHFA target standard. METHODS. We prospectively examined patients who were admitted with hip fractures between 1. st. April to 31. st. July 2011. These included admissions from A&E and inpatients. Patients who did not receive surgical treatment were excluded. Information was collected using the same pro forma as the SHFA group. RESULTS. There were 72 patients with hip fractures in that period. One patient (1.4%) was considered unfit for surgery and therefore excluded. Sixty-five patients were considered fit for surgery on first assessment and 61 (93.8%) had surgery within the target time. There were three patients (4.6%) whose diagnosis was delayed waiting for MRI. The waiting period included a weekend in two patients, when there were no MRI facilities. Only one patient (1.5%) had surgery delayed due to lack of theatre availability. DISCUSSION. Having surgery performed as early as possible is associated with a beneficial impact on morbidity, complications and length of hospital stay. 2–4. , reflected with SIGN guidelines stating “surgery should be performed as soon as the medical condition allows”. 5. and NICE recommending surgery within 48 hours of admission. 6. . CONCLUSION. Although our rate of 93.8% does not meet the target standard, it represents an improvement from the published rate (91.2%) in 2008. It also highlights the areas for improvement in patient care, particularly in getting MRIs swiftly to avoid delays

Summary. We found good to excellent reproducibility of in vivo hip joint angle measurements during repeated sitting when derived from registering low-resolution Open MRI imagesets with a reference high-resolution conventional MRI scan, despite only moderate similarity of the segmented volumes. Keywords: hip, kinematics, MRI, femoroacetabular impingement, repeatability. Introduction. Femoroacetabular impingement (FAI) is a mechanical hip disorder caused by an abnormal bony contact between the femur and acetabulum. Open MRIs can enable studies of FAI under weightbearing, but the resolution of such scans is comparatively low, so it is useful to obtain high resolution (HR) reference scans from a conventional MRI and register lower resolution (LR) open MRI images to the HR images. The purpose of this study was to establish the degree of correspondence between the segmented volumes from the two types of scanner and to estimate the repeatability of joint angle measurements. Patients and Methods. Three healthy subjects were scanned in a lying position to obtain high resolution (HR) MRI images of the pelvis, hip and knee. The same subjects were scanned four times in a sitting position in a 0.5T open MRI scanner to obtain corresponding low resolution (LR) images of the hip joint. Between sittings, subjects rose and sat again, and during each sitting, a block was inserted and removed from underneath their foot. Volumetric models of the femur and acetabulum were manually segmented from the HR and LR MRI images. The LR (sitting) models were registered to the HR (supine) models using an intensity-based rigid registration method and the degree of overlap and the femoropelvic joint angles computed. Analysis is complete for two of the three subjects (results for the third are pending). Results. The overlap between the LR and HR imagesets is reasonable in most scan slices - per-slice Dice Similarity Coefficients (DSCs) are typically around 85%, although DSCs near the edges of volumes can sometimes drop to about 75%. Nonetheless, the resulting registrations are relatively insensitive to these moderate discrepancies. For the two subjects whose data has been analyzed to date, the femoral angle relative to the scanner is quite repeatable (SD < 0.9° for the flexion angle under each block condition). The mean femoral flexion angle change between block conditions was also comparatively consistent (SD 1.7° & 2.2° for the two subjects), but most of the other hip joint angles (and changes between the up and down conditions) were more variable (SDs up to ∼5.7°). Discussion/Conclusions. Although there are moderate discrepancies between the LR and HR segmented volumes, the resulting registrations and estimated joint angles are relatively consistent (SDs under 2°). The larger degree of pelvic flexion variability under repositioning indicates that it may be challenging for subjects to reproduce a desired posture on different occasions. Our results could not be directly compared with the only other studies we are aware of using open MRI to investigate FAI because neither combined LR and HR images

There has been only one limited report dating from 1941 using dissection which has described the tibiofemoral joint between 120° and 160° of flexion despite the relevance of this arc to total knee replacement. We now provide a full description having examined one living and eight cadaver knees using MRI, dissection and previously published cryosections in one knee.

In the range of flexion from 120° to 160° the flexion facet centre of the medial femoral condyle moves back 5 mm and rises up on to the posterior horn of the medial meniscus. At 160° the posterior horn is compressed in a synovial recess between the femoral cortex and the tibia. This limits flexion. The lateral femoral condyle also rolls back with the posterior horn of the lateral meniscus moving with the condyle. Both move down over the posterior tibia at 160° of flexion.

Neither the events between 120° and 160° nor the anatomy at 160° could result from a continuation of the kinematics up to 120°. Therefore hyperflexion is a separate arc. The anatomical and functional features of this arc suggest that it would be difficult to design an implant for total knee replacement giving physiological movement from 0° to 160°.