Introduction. Shoulder motion results from a complex interaction between the interconnected segments of the shoulder girdle. Coordination is necessary for normal shoulder function and is achieved by synchronous and coordinated muscle activity. During rotational movements, the humeral head translates on the glenoid fossa in the anterior-posterior plane. Tension developed by the rotator cuff muscles compresses the humeral head into the glenoid fossa. This acts to limit the degree of humeral head translation and establishes a stable GH fulcrum about which the arm can be moved. Previous studies have been limited by the use of contrived movement protocols and muscular coordination has not been previously considered with regard to shoulder rotation movements. This study reports the activation profile and coordination of 13 muscles and 4 muscle groups during a dynamic rotational movement task based on activities of daily living. Methods. Eleven healthy male volunteers were included in the study. Electromyography (EMG) was recorded from 13 muscles (10 surface and 3 fine-wire intramuscular electrodes) using a wireless EMG system. EMG was recorded during a movement task in which the shoulder was consecutively rotated internally (phase 1) and externally (phase 2) with a weight in the hand. Muscle group data was calculated by ensemble averaging the activity of the individual component muscles. Mean signal amplitude and Pearson correlation coefficient (PCC) analysed muscle activation and coordination, respectively. Results. The mean length of phase 1 (internal rotation) and phase 2 (external rotation) was 1.1s (SD+0.15) and 1.09s (SD+0.18), respectively with no significant difference between them. Mean signal amplitude was significantly higher during external rotation for the anterior, middle and posterior deltoid, teres major and the rotator cuff muscles (Table 1). Significant positive correlations were identified between the activation patterns of the deltoid and rotator cuff groups (PCC=0.95, p=<0.001), the deltoid and latissimus dorsi-teres major groups (PCC=0.74, p=<0.001) and the latissimus dorsi-teres major and rotator cuff groups (PCC=0.87, p=<0.001) (Figure1). Discussion. The subscapularis is extensively described as an internal rotator of the glenohumeral joint; however, during this study it was primarily active during external rotation. During activities of daily living the subscapularis balances the force generated by the supraspinatus and infraspinatus by contracting eccentrically as external rotation progresses. This balance between the anterior and posterior rotator cuff maintains anterior-posterior stability of the humeral head on the glenoid fossa. There is a highly coordinated and synchronous relationship between all the major muscle groups of the shoulder during rotational activities, which ensures glenohumeral joint stability. The function of the shoulder muscles is task specific. This has important implications when considering the impact of muscle pathology on shoulder dysfunction and the treatment strategies employed

INTRODUCTION

Knee simulators are being used to evaluate wear. The current international standards have been developed from clinical investigations of the normal knee [1, 2] or from a single TKA patient [3, 4]. However, the forces and motions in a TKA patient differ from a normal knee and, furthermore, the resulting kinematic outcomes after TKA will depend on the design of the device [5]. Consequently, these standard tests may not recreate in-vivo conditions; therefore, the goal of this study was to perform a novel wear simulation using design-specific inputs that have been derived from fluoroscopic images of a deep knee bend.

Background. Medical advances and an ageing population mean that more people than ever rely on artificial joints. In the past years, shoulder joint replacement has developed rapidly and the numbers of shoulder prostheses implanted increased dramatically. Wear is one of the main contributors to the failure of shoulder implants. It is therefore important to measure the wear properties of the articulating surfaces within the joint in vitro. Investigation of wear characteristics through a comprehensive range of motion using a sophisticated shoulder simulator would reveal the durability of the material, the performance of component design and the safety analyses of prostheses. The purpose of the work was to develop and validate a multi-station shoulder simulator, which could accurately simulate physiological gleno-humeral forces and displacements during activities of daily living. Materials and Methods. Imperial shoulder simulator was designed with six articulating stations and one loaded soak control station for anatomical shoulder system wear simulation. It gives an adduction-abduction (AA) range of-15° to 55°, flexion-extension (FE) range of −90° to 90° and internal external rotation (IER) range of 15° to −90°. The rotations are applied simultaneously to the humeral implants by using stepper motors with integral position encoders. Axial and shear loadings to each glenoid implant were applied using pneumatic cylinders. Force controlled translations were recorded using load cells and LVDTs, and a data acquisition system. Pneumatic cylinders were also installed to work to counterbalance weights during the motion of adduction-abduction. All bearing pairs are within isolated and sealed test chambers to prevent loss of fluid through evaporation, and cross contamination of third body wear (as recommended in F1714-96). The simulator is controlled by LabVIEW program allowing to reproduce shoulder activities of daily living. Results. A commissioning trial was conducted when shoulder implants were subject to rotational and translational motions and loading to replicate the ‘combing’ activity of daily living. The motion ranges were typically 5° to 15° in AA, 15° to 80° in FE, and −30° to −20° in IER with applied loads from 60 to 440 N, principally along the medio-lateral direction. The waveform was at frequency of 1 Hz. The activity was loaded at 250,000 cycles around 3 full days, when test and control specimens should be cleaned, measured and then re-installed into the simulator. The results from kinematic and kinetic inputs and outputs were obtained from the trial study. Discussion. A multi-station shoulder simulator was successfully developed, which is capable of reproducing typical activities of daily living by applying physiological patterns of motion and load. The performance of the simulator was validated in the commissioning trial, which leads to evaluation of novel implant designs

Introduction. Accurate measurement of knee motion is necessary for assessment of natural joint function and in the diagnosis of pathology. In particular, precise knowledge of natural knee mechanics provides useful metrics for comparison to knee function following total knee arthroplasty (TKA). Reported measurements of natural knee kinematics during activities of daily living are rare, and often do not include both tibiofemoral (TF) and patellofemoral (PF) articulations. What's more, most studies record knee motion of younger subjects that are not necessarily representative of the age range associated with degenerative changes and TKA. The purpose of this study was to measure TF and PF kinematics of healthy older adults as they performed activities of daily living, including tasks considered more demanding for the knee [1]. Methods. High speed stereo radiography (HSSR) was used to measure the kinematics of the PF and TF joints. HSSR utilizes two views of the knee to capture 3D sub-mm measurements accurate to within ±0.15 mm in translation and ±0.41° in rotation [2]. Eight healthy subjects (4M/4F, 64.4±8.2 years, BMI: 27.6±4.8 kg/m2) performed six activities of daily living: seated knee extension, lunge, chair rise, gait, pivot and step down (Figure 1). The 3D geometry of the femur, tibia, and patella of each subject was reconstructed from CT and used to track bone motions using Autoscoper (Brown University, Providence RI). Motion of the tibia and patella were reported relative to a coordinate system centered in the posterior condyles of the femur [3]. Average range of motion (ROM) for each DOF was calculated as the difference between the maximum and the minimum value and averaged across the subjects for each activity. Results and Discussion. Average patella ROM during the lunge and chair-rise activities was within the ROM of the knee extension, demonstrating consistent tracking of the patella during the loaded deep flexion activities. Tibia motion relative to the femur was consistent in trend during the knee extension, lunge, and chair rise, with the exceptions of increased internal rotation and anterior translation during weight bearing (Figure 2a). In agreement with in vitro studies [4], tibial and patellar internal rotation increased with knee flexion consistently across the high knee flexion activities (Figure 2a). Tibial and patellar external rotation increased as the subjects approached heel-off as they executed a pivot (Figure 3a). Higher-demand tasks, pivot and step down, presented larger ROM than gait with notable increase in tibial external rotation and patellar flexion, respectively (Figure 3b). The decreasing congruence of the patella and trochlea as the knee extends likely explains the greater variability in patella ROM in gait, pivot, and step down activities [5]. In conclusion, evaluating natural kinematics of the tibia and patella and their interaction during a variety of activities of daily living provides a standard for the evaluation of knee pathology and treatment

Fracture related infection, in particular chronic osteomyelitis, requires complex management plans. Meta analyses and systematic reviews have not found a gold standard of treatment for this disease. In 2017 an alternative treatment protocol was undertaken in our institution; whereby staged surgery with the use of cheaply manufactured tailored antibiotic cement rods was used in the treatment of chronic osteomyelitis, secondary to traumatic long bone fractures. Short term outcomes for this protocol demonstrated a 75.7% microbiological resolution to a negative culture and a good clinical outcome of 84.2% overall was demonstrated in terms of sinus resolution, skin changes, pain and function. Our aim now was to assess the long term outcomes of this treatment strategy. A cross-sectional study of patients who had previously undergone the set treatment protocol was performed. Patient satisfaction, effects on activities of daily living, return to work and clinical improvement at 5 years following the intervention were assessed using a patient questionnaire and the validated AAOS lower limb score. The average AAOS lower limb score was 88 which was en par to other similar studies. 80% of patients had returned to some form of work. Ongoing mild pain was a persistent problem for 50% of the patients however 98% of the patients were overall satisfied with the treatment satisfaction at 5 years. Only 1 patient required further treatment. 8 patients could not be located for follow up. Chronic osteomyelitis remains a complex disease to treat. This treatment protocol demonstrates favourable microbiological, serological and clinical short term outcomes and favourable patient satisfaction and functional long term outcomes at 5 years. Our study highlights antibiotic targeted cement rods as a feasible treatment option in managing chronic osteomyelitis

Treatment of posterior malleolar (PM) ankle fractures remain controversial. Despite increasing recommendation for small PM fragment fixation, high quality evidence demonstrating improved clinical outcomes over the unfixated PM is limited. We describe the medium-to-long term clinical and radiographical outcomes in younger adult patients with PM ankle fractures managed without PM fragment fixation. A retrospective cohort study of patients aged 18–55 years old admitted under our orthopaedic unit between 1st of April 2009 and 31st of October 2013 with PM ankle fractures was performed. Inclusion criteria were that all patients must mobilise independently pre-trauma, have no pre-existing ankle pathologies, and had satisfactory bimalleolar and syndesmotic stabilisation. Open fractures, talar fractures, calcaneal fractures, pilon fractures, subsequent re-injury and major complications were excluded. All PM fragments were unfixated. Clinical outcomes were evaluated using Foot and Ankle Ability Measure (FAAM) with activities of daily living (ADL) and sports subscale, visual analogue scale (VAS) and patient satisfaction ratings. Osteoarthrosis was assessed using modified Kellgren-Lawrence scale on updated weightbearing ankle radiographs. 61 participants were included. Mean follow-up was 10.26 years. Average PM size was 16.19±7.39%. All participants were evaluated for clinical outcomes, demonstrating good functional outcomes (FAAM-ADL 95.48±7.13; FAAM-Sports 86.39±15.52) and patient satisfaction (86.16±14.42%), with minimal pain (VAS 1.13±1.65). Radiographical outcomes were evaluated in 52 participants, showing no-to-minimal osteoarthrosis in 36/52 (69.23%), mild osteoarthrosis in 14/52 (26.92%) and moderate osteoarthrosis in 2/52 (3.85%). Clinical outcomes were not associated with PM fragment size, post-reduction step-off, dislocation, malleoli fractured or syndesmotic injury. PM step-off and dislocation were associated with worse radiographical osteoarthrosis. Other published medium-to-long term studies reported overall good outcomes, with no differences after small fragment fixation. The unfixated smaller posterior malleolus fragment demonstrated overall satisfactory clinical and radiographical outcomes at 10-year follow-up and may be considered a valid treatment strategy

A huge commitment is required from patients and families who undergo a limb reconstruction procedure using the hexapod frame. This includes turning the struts on the frame, pin site care and intensive rehabilitation. Montpetit et al (2009) discovered that function, participation, engagement in regular activities of daily living is severely impacted during the hexapod lengthening period. Due to the long duration and burden for families, it is imperative that healthcare professionals understand the impact that the hexapod frame has on functional abilities and health related quality of life (HRQL). This project involved a retrospective review of prospectively collected data on function and HRQL during two periods of time: (1) when the hexapod frame is applied on the child's lower extremity and (2) when the lengthening phase is completed, and the hexapod frame is removed. Data from 38 children (mean age: 12 years SD 3.8) who completed lower extremity reconstruction using the hexapod frame and completed either or both the Pediatric Quality of Life Inventory 4.0 Generic Core Scale (PedsQL) and Pediatric Outcomes data Collection Instrument (PODCI) was included. Analysis included, standardized response means, the non-parametric Wilcoxon test and effect size calculation. A Wilcoxon signed rank test for those children who completed pre and post frame PODCI’;s revealed those scores were significantly greater once the hexapod frame was removed (Md=85.10, n=10) compared to during (Md=66.50, n=10) with a large effect size, r= 1.45. Similar, the PedsQL scores improved post frame removal (Md= 66.30, n=10) compared to during treatment (Md = 53.34, n=10), with a medium size effect, r= 0.62. All subtests improved once the frame was removed. This study provides essential insights into the burden of the hexapod frame for children and provides valuable information for all allied healthcare professionals targeted interventions for health domains. This study shows that children's function improves once the hexapod frame is removed. However, this study highlights the importance for all healthcare professional to address health domains for the duration of the hexapod procedure where the child scored lower e.g. sports and physical function, pain and comfort, happiness from the PODCI. The PedsQL identified lower mean scores in physical and emotional function

Introduction & Aims. Patient recovery after total knee arthroplasty remains highly variable. Despite the growing interest in and implementation of patient reported outcome measures (e.g. Knee Society Score, Oxford Knee Score), the recovery process of the individual patient is poorly monitored. Unfortunately, patient reported outcomes represent a complex interaction of multiple physiological and psychological aspects, they are also limited by the discrete time intervals at which they are administered. The use of wearable sensors presents a potential alternative by continuously monitoring a patient's physical activity. These sensors however present their own challenges. This paper deals with the interpretation of the high frequency time signals acquired when using accelerometer-based wearable sensors. Method. During a preliminary validation, five healthy subjects were equipped with two wireless inertial measurement units (IMUs). Using adhesive tape, these IMU sensors were attached to the thigh and shank respectively. All subjects performed a series of supervised activities of daily living (ADL) in their everyday environment (1: walking, 2: stair ascent, 3: stair descent, 4: sitting, 5: laying, 6: standing). The supervisor timestamped the performed activities, such that the raw IMU signals could be uniquely linked to the performed activities. Subsequently, the acquired signals were reduced in Python. Each five second time window was characterized by the minimum, maximum and mean acceleration per sensor node. In addition, the frequency response was analyzed per sensor node as well as the correlation between both sensor nodes. Various machine learning approaches were subsequently implemented to predict the performed activities. Thereby, 60% of the acquired signals were used to train the mathematical models. These models were than used to predict the activity associated with the remaining 40% of the experimentally obtained data. Results. An overview of the obtained prediction accuracy per model stratified by ADL is provided in Table 1. The Nearest Neighbor and Random Forest algorithms performed worse compared to the Support Vector Machine and Decision Tree approaches. Even for the latter, differentiating between walking and stair ascent/descent remains challenging as well as differentiating between sitting, standing and laying. The prediction accuracies are however exceeding 90% for all activities when using the Support Vector Machine approach. This is further illustrated in Figure 1, indicating the actual versus predicted activity for the validation set. Conclusions. In conclusion, this paper presents an evaluation of different machine learning algorithms for the classification of activities of daily living from accelerometer-based wearable sensors. This facilitates evaluating a patient's ability to walk, climb or descend stairs, stand, lay or sit on a daily basis, understanding how active the patient is overall and which activities are routinely performed following arthroplasty surgery. Currently, effort is undertaken to understand how participation in these activities progresses with recovery following total knee arthroplasty

Introduction. Soft tissue artefact (STA) affects the kinematics retrieved with skin marker-based motion capture, and thus influences the outcomes of biomechanical models that rely on such kinematics. To date, compensation for STA remains an unsolved challenge due to its complexity. Factors include its dependency on subject, on motion activity and on skin-marker configuration, its non-linearity over the movement cycle, and the scarcity of reference in-vivo estimations. The objective of this study was extending the existing knowledge of the effects of STA on the kinematics of the hip joint and on the hip joint center location, by quantifying them for a sample total hip arthroplasty (THA) population, for a broader range of activities of daily living (ADLs). Methods. Four activities of daily living (overground gait, stairs descent, chair rise and putting on socks) were measured simultaneously with optical motion capture (MC) at 100 Hz and with a movable single-plane video-fluoroscopy system (VF) at 25 Hz, for fifteen patients with successful total hip arthroplasty (THA). The joint segment positions were computed by least-square fitting for MC and by semi-automatic 2D/3D registration for VF. Anatomical coordinate systems were defined for each joint segment based on skin markers location at a reference standing position. Errors induced by STA on the retrieved joint motion were computed as the difference between MC-based kinematics and the reference VF-based kinematics. Statistical analysis was carried out to determine the whether the differences between the kinematics obtained with the two methods were significant. Results. MC underestimated the ROM of the hip joint for all activities. The ROM for the flexion-extension was underestimated by on average 4.1°, 6.5°, 8.0° and 6.9° for gait, stair decent, chair rise and putting on socks respectively. Overall, during dynamic activities the hip joint was less flexed, more adducted and more internally rotated as retrieved using MC, compared to VF. The flexion angle was underestimated by MC during late stance phase and early swing phase for both gait and stairs descent. The internal rotation of the hip was overestimated by MC throughout the whole cycle of each activity. MC error for the thigh was larger than the MC error for the pelvis. MC errors above 1 cm were observed for the location of the hip joint center, with higher values for the cranial-caudal direction. Discussion. Reduced ROM supports the notion that skin-sliding is a major contributor to STA. The underestimation of hip flexion appeared to be positively correlated to the degree of flexion. Larger skin deformation and sliding occurring for the thigh at higher hip flexion angles may produce the observed patterns of MC error for FE. The CC error was possibly due to inertial effects, and was more pronounced for the stair descent due to larger vertical movement and acceleration. This study led further bases for the activity-dependent correction of STA. This has the potential of improving the accuracy of motion capture and boosting its use for motion analysis as opposite to video-fluoroscopy techniques, which deliver radiation dose to the subjects

Aim. Musculoskeletal infection is a serious complication, however literature is lacking prospective data on its impact on mental health. The study aimed to assess mental health in patients with musculoskeletal infections and how they experience the possible mental and physical impairment. Method. All patients treated in our unit for musculoskeletal infections between July 2020 and March 2022 were prospectively included. To assess specific patient reported outcomes the following questionnaires were used: World-Health-Organization Quality-Of-Life (WHOQOL)-BREF and the Veterans-RAND-12Item Health Survey (VR-12) for mental & physical health; Patient-Health-Questionnaire (PHQ-8) for depression symptoms; Generalized-Anxiety-Disorder-Scale-7 (GAD-7) for anxiety symptoms and Somatic-Symptom-Disorder-B Criteria Scale (SSD-12) for experience of mental & physical impairment. The surveys were conducted at baseline, 6 and 12-weeks and 1-year. Results. In total 199 patients were included (31 fracture-related infections, 80 prosthetic joint infections, 40 diabetic foot syndromes and 48 other musculoskeletal infections). Physical health was significantly worse 6 weeks after treatment compared to baseline (WHOQOL p=.002; VR-12 p<.001), but significantly better at 3-months (p<.001; p=.006) and 12-months (p=.003; p<.001). Mental health was significantly worse at 3-months (WHOQOL p=.002), but at final follow-up significantly better (VR-12 p=.046). Social relationships (domain of WHOQOL) were perceived significantly worse 6 weeks and 12 months after treatment initiation (p=.003; p=.007), as were environmental factors. At baseline moderate to severe depression symptoms (PHQ-8≥10) and moderate to severe anxiety symptoms (GAD-7≥10) were observed in 14.6%, respectively 10.6% of all patients. At 12-months these were 7.4% and 3%. Over the course of treatment, only patients with DFS showed a significant change in experienced psychological or physical impairment, which was perceived significantly less compared 6 weeks to 12 months (p=.042). Conclusions. Patients with musculoskeletal infections suffer from a considerable impact on their mental health. The greatest impairment in physical health was seen 6 weeks after beginning of treatment. The psychological well-being was worse at 3-months. Environmental factors, such as mobility, activities of daily living and dependence on medication or medical treatment were worst at 3-months. Also increasingly worse social relationships over the course of treatment was observed. Further studies are needed to identify psychological impairment and related factors, as well as to determine how patients cope with their disease and treatment. This could serve as a foundation to implement treatment algorithms in order to improve patient related outcome and quality of life

INTRODUCTION. Porous metal bone fillers are frequently used to manage bony defects encountered in revision total knee arthroplasty (rTKA). Compared to structural graft, porous metal bone fillers have shown significantly lower loosening and failure rates potentially due to osseointegration and increased material strength [1]. The strength of porous metal bone fillers used in lower extremities is frequently assessed using compression/shear/torsion test methods, adapted from spine standards. However, these basic methods may lack clinical relevance, and do not provide any insight on the relationship between patient activity and anticipated prosthesis performance. The goal of this study was to evaluate the response of bone fillers under different activities of daily living, in order to define physiologically relevant worst case biomechanics for component evaluation. METHODS. A bone filler tibial augment is shown in Figure 1. A test construct for tibial augments (half-block each for medial and lateral sides) is shown in Figure 2, along with compatible rTKA components. An additional void in the bone was filled using bone cement. Loading was applied through the tibiofemoral contact patches created on polyethylene tibial insert. Loading was used for two activities of daily living; walking and deep knee bend [2–3]. During walking, the tibiofemoral contact patch on the anterior tibial post gets loaded due to femoral hyperextension with 1.2xbody weight (BW), whereas the medial and lateral condyles get loaded with 3xBW compressive load. For deep knee bend, only the condyles get loaded with 4.34xBW. Compared to walking, 45% higher compressive load magnitude in deep knee bend located further posterior was anticipated to create a larger bending moment and induce higher stress on the half augments. A finite element analysis (FEA) was performed by modeling this test construct with a medium size tibial augment. All components were modeled using linear elastic material properties. All interfaces, including the augment-bone interface (representing full bony ingrowth construct) were modeled using bonded contact. The inferior surface of the bone analogue was constrained. Linear static analyses were performed and peak von mises stress predicted in the tibial augments was compared between activities. RESULTS. Deep knee bend resulted in 31% higher stresses in the tibial augments than for walking. High von mises stresses were mostly predicted at the superior/posterior aspect of the internal side of the augment and in the corners of the cutouts. Figure 3 presents the von mises stresses in the tibial augments for both loading scenarios. DISCUSSION. This study revealed that the 45% increased posterior compressive load associated with deep knee bend is a more significant factor than the moment applied to the post during walking gait for a hyperextended knee, when considering the stress in bone filler augments in revision TKA. The stress in the augments can depend on multiple factors and the proposed FEA method can be used to compare stresses in different porous material bone fillers to determine worst case for assessing its strength

Arthroscopic hip procedures have increased dramatically over the last decade as equipment and techniques have improved. Patients who require hip arthroscopy for femoroacetabular impingement on occasion require surgery on the contralateral hip. Previous studies have found that younger age of presentation and lower Charlson comorbidity index have higher risk for requiring surgery on the contralateral hip but have not found correlation to anatomic variables. The purpose of this study is to evaluate the factors that predispose a patient to requiring subsequent hip arthroscopy on the contralateral hip. This is an IRB-approved, single surgeon retrospective cohort study from an academic, tertiary referral centre. A chart review was conducted on 310 primary hip arthroscopy procedures from 2009-2020. We identified 62 cases that went on to have a hip arthroscopy on the contralateral side. The bilateral hip arthroscopy cohort was compared to unilateral cohort for sex, age, BMI, pre-op alpha angle and centre edge angle measured on AP pelvis XRay, femoral torsion, traction time, skin to skin time, Tonnis grade, intra-op labral or chondral defect. A p-value <0.05 was deemed significant. Of the 62 patients that required contralateral hip arthroscopy, the average age was 32.7 compared with 37.8 in the unilateral cohort (p = 0.01) and BMI was lower in the bilateral cohort (26.2) compared to the unilateral cohort (27.6) (p=0.04). The average alpha angle was 76.3. 0. in the bilateral compared to 66. 0. in the unilateral cohort (p = 0.01). Skin to skin time was longer in cases in which a contralateral surgery was performed (106.3 mins vs 86.4 mins) (p=0.01). Interestingly, 50 male patients required contralateral hip arthroscopy compared to 12 female patients (p=0.01). No other variables were statistically significant. In conclusion, this study does re-enforce existing literature by stating that younger patients are more likely to require contralateral hip arthroscopy. This may be due to the fact that these patients require increased range of motion from the hip joint to perform activities such as sports where as older patients may not need the same amount of range of motion to perform their activities. Significantly higher alpha angles were noted in patients requiring contralateral hip arthroscopy, which has not been shown in previous literature. This helps to explain that larger CAM deformities will likely require contralateral hip arthroscopy because these patients likely impinge more during simple activities of daily living. Contralateral hip arthroscopy is also more common in male patients who typically have a larger CAM deformity. In summary, this study will help to risk stratify patients who will likely require contralateral hip arthroscopy and should be a discussion point during pre-operative counseling. That offering early subsequent or simultaneous hip arthroscopy in young male patients with large CAMs should be offered when symptoms are mild

Analyzing shoulder kinematics is challenging as the shoulder is comprised of a complex group of multiple highly mobile joints. Unlike at the elbow or knee which has a primary flexion/extension axis, both primary shoulder joints (glenohumeral and scapulothoracic) have a large range of motion (ROM) in all three directions. As such, there are six degrees of freedom (DoF) in the shoulder joints (three translations and three rotations), and all these parameters need to be defined to fully describe shoulder motion. Despite the importance of glenohumeral and scapulothoracic coordination, it's the glenohumeral joint that is most studied in the shoulder. Additionally, the limited research on the scapulothoracic primarily focuses on planar motion such as abduction or flexion. However, more complex motions, such as internally rotating to the back, are rarely studied despite the importance for activities of daily living. A technique for analyzing shoulder kinematics which uses 4DCT has been developed and validated and will be used to conduct analysis. The objective of this study is to characterize glenohumeral and scapulothoracic motion during active internal rotation to the back, in a healthy young population, using a novel 4DCT approach. Eight male participants over 18 with a healthy shoulder ROM were recruited. For the dynamic scan, participants performed internal rotation to the back. For this motion, the hand starts on the abdomen and is moved around the torso up the back as far as possible, unconstrained to examine variability in motion pathway. Bone models were made from the dynamic scans and registered to neutral models, from a static scan, to calculate six DoF kinematics. The resultant kinematic pathways measured over the entire motion were used to calculate the ROM for each DoF. Results indicate that anterior tilting is the most important DoF of the scapula, the participants all followed similar paths with low variation. Conversely, it appears that protraction/retraction of the scapula is not as important for internally rotating to the back; not only was the ROM the lowest, but the pathways had the highest variation between participants. Regarding glenohumeral motion, internal rotation was by far the DoF with the highest ROM, but there was also high variation in the pathways. Summation of ROM values revealed an average glenohumeral to scapulothoracic ratio of 1.8:1, closely matching the common 2:1 ratio other studies have measured during abduction. Due to the unconstrained nature of the motion, the complex relationship between the glenohumeral and scapulothoracic joints leads to high variation in kinematic pathways. The shoulder has redundant degrees of freedom, the same end position can result from different joint angles and positions. Therefore, some individuals might rely more on scapular motion while others might utilize primarily humeral motion to achieve a specific movement. More analysis needs to be done to identify if any direct correlations can be drawn between scapulothoracic and glenohumeral DoF. Analyzing the kinematics of the glenohumeral and scapulothoracic joint throughout motion will further improve understanding of shoulder mechanics and future work plans to examine differences with age

Introduction. Hip Arthrodesis had been considered as a useful surgical option in young adult patient with high activity demands suffering from osteoarthritis of the hip. Although the procedure surely eliminates pain of the hip joint, it can also cause disorders of the adjacent joints in addition to the complete loss of motion, might consequently deteriorate the activity of daily living. The purpose of this retrospective study was to investigate the efficacy and drawback of hip arthrodesis, focusing on the effect of this procedure on the adjacent joints. Materials and Methods. From 1976 to 1989, 29 hip arthrodesis were performed and 22 hips were followed up (1 died, 6 lost). Disorders led to arthrodesis were septic arthritis (1 hip), post-traumatic (1), osteonecrosis (1), primary osteoarthritis (3), and secondary osteoarthritis due to DDH (16). The average age at surgery was 38 years (range, 19–53 years, 6 men and 16 women). Hip arthrodesis was indicated for young active adults with end stage osteoarthritis, who had normal or mild osteoarthritis in contralateral hip and needed physical labor. The hip was positioned in 30 degrees of flexion, 0 to 5 degree of external rotation, and 0 to 5 degree of abduction. Clinical and radiographic assessment was done for these patients. The clinical follow-up consisted of questionnaire which assessed ability of typical Japanese daily living movement and patient's satisfaction. The condition of the adjacent joints was evaluated clinically and radiographically. Results. After an average follow-up of 22 years (range15-28), no patients complained of pain in the fused hip joint. On the other hand, pain in the adjacent joints was seen frequently. Seventeen (77%) of 22 patients had low back pain and one of these patients, who had severe low back pain, required conversion of arthrodesis to THA. Ten patients (45%) had contralateral hip pain and 8 (36%) of whom subsequently needed THA. All patients who required THA had early stage osteoarthritis when they underwent arthrodesis. Ten patients (45%) had knee pain (5 in the ipsilateral and 5 in the contralateral knee). Radiographic progression of osteoarthritis in adjacent joints was also seen frequently, namely, 9 in lumbar spine, 11 in contralateral hip, 6 in ipsilateral and 6 in contralateral knee. Although pain in the involved hip disappeared, activity of daily living was severely deteriorated (impossible to clip nail: 88%, ride a bicycle: 94%, use a Japanese toilet: 75%, sit in Japanese style: 50%). As a result, only 4 patients (18%) were satisfied with the hip arthrodesis. Discussion. The satisfaction of hip arthrodesis was unexpectedly poor despite of pain relief of involved hip joint. One of essential reasons was activity of daily living in Japanese style, which requires relatively deep flexion in hip and knee. Compensation of limited movement in hip might cause pain and progression of osteoarthritic change in adjacent joints. Another vital reason was that we indicated this procedure for bilateral DDH case whose contralateral hip had early stage osteoarthritis, ended up with THA in most cases

One in five patients remain unsatisfied due to ongoing pain and impaired mobility following total knee arthroplasty (TKA). It is important if surgeons can pre-operatively identify which patients may be at risk for poor outcomes after TKA. The purpose of this study was to determine if there is an association between pre-operative measures and post-operative outcomes in patients who underwent TKA. This study included 28 patients (female = 12 / male = 16, age = 63.6 ± 6.9, BMI = 29.9 ± 7.4 kg/m2) with knee osteoarthritis who were scheduled to undergo TKA. All surgeries were performed by the same surgeon (GD), and a subvastus approach was performed for all patients. Patients visited the gait lab within one-month of surgery and 12 months following surgery. At the gait lab, patients completed the knee injury and osteoarthritis outcome score (KOOS), a timed up and go (TUG), and walking task. Variables of interest included the five KOOS sub-scores (symptoms, pain, activities of daily living, sport & recreation, and quality of life), completion time for the TUG, walking speed, and peak knee biomechanics variables (flexion angle, abduction moment, power absorption). A Pearson's product-moment correlation was run to assess the relationship between pre-operative measures and post-operative outcomes in the TKA patients. Preliminary analyses showed the relationship to be linear with all variables normally distributed, as assessed by Shapiro-Wilk's test (p > .05), and there were no outliers. There were no statistically significant correlations between any of the pre-operative KOOS sub-scores and any of the post-operative biomechanical outcomes. Pre-operative TUG time had a statistically significant, moderate positive correlation with post-operative peak knee abduction moments [r(14) = .597, p < .001] and peak knee power absorption [r(14) = .498, p = .007], with pre-operative TUG time explaining 36% of the variability in peak knee abduction moment and 25% of the variability in peak knee power absorption. Pre-operative walking speed had a statistically significant, moderate negative correlation with post-operative peak knee abduction moments [r(14) = -.558, p = .002] and peak knee power absorption [r(14) = -.548, p = .003], with pre-operative walking speed explaining 31% of the variability in peak knee abduction moment and 30% of the variability in peak knee power absorption. Patient reported outcome measures (PROMs), such as the KOOS, do indicate the TKA is generally successful at relieving pain and show an overall improvement. However, their pre-operative values do not correlate with any biomechanical indicators of post-operative success, such as peak knee abduction moment and knee power. Shorter pre-operative TUG times and faster pre-operative walking speeds were correlated with improved post-operative biomechanical outcomes. These are simple tasks surgeons can implement into their clinics to evaluate their patients. Future research should expand these findings to a larger sample size and to determine if other factors, such as surgical approach or implant design, improves patient outcomes

Individuals with multi-compartment knee osteoarthritis (KOA) frequently experience challenges in activities of daily living (ADL) such as stair ambulation. The Levitation “Tri-Compartment Offloader” (TCO) knee brace was designed to reduce pain in individuals with multicompartment KOA. This brace uses novel spring technology to reduce tibiofemoral and patellofemoral forces via reduced quadriceps forces. Information on brace utility during stair ambulation is limited. This study evaluated the effect of the TCO during stair descent in patients with multicompartment KOA by assessing knee flexion moments (KFM), quadriceps activity and pain. Nine participants (6 male, age 61.4±8.1 yrs; BMI 30.4±4.0 kg/m2) were tested following informed consent. Participants had medial tibiofemoral and patellofemoral OA (Kellgren-Lawrence grades two to four) diagnosed by an orthopaedic surgeon. Joint kinetics and muscle activity were evaluated during stair descent to compare three bracing conditions: 1) without brace (OFF); 2) brace in low power (LOW); and 3) brace in high power (HIGH). The brace spring engages from 60° to 120° and 15° to 120° knee flexion in LOW and HIGH, respectively. Individual brace size and fit were adjusted by a trained researcher. Participants performed three trials of step-over-step stair descent for each bracing condition. Three-dimensional kinematics were acquired using an 8-camera motion capture system. Forty-one spherical reflective markers were attached to the skin (on each leg and pelvis segment) and 8 markers on the brace. Ground reaction forces and surface EMG from the vastus medialis (VM) and vastus lateralis (VL) were collected for the braced leg. Participants rated knee pain intensity performing the task following each bracing condition on a 10cm Visual Analog Scale ranging from “no pain” (0) to “worst imaginable pain” (100). Resultant brace and knee flexion angles and KFM were analysed during stair contact for the braced leg. The brace moment was determined using brace torque-angle curves and was subtracted from the calculated KFM. Resultant moments were normalized to bodyweight and height. Peak KFMs were calculated for the loading response (Peak1) and push-off (Peak2) phases of support. EMG signals were normalized and analysed during stair contact using wavelet analysis. Signal intensities were summed across wavelets and time to determine muscle power. Results were averaged across all 3 trials for each participant. Paired T-tests were used to determine differences between bracing conditions with a Bonferroni adjustment for multiple comparisons (α=0.025). Peak KFM was significantly lower compared to OFF with the brace worn in HIGH during the push-off phase (p Table 1: Average peak knee flexion moments, quadriceps muscle power and knee pain during stair descent in 3 brace conditions (n=9). Quadriceps activity, knee flexion moments and pain were significantly reduced with TCO brace wear during stair descent in KOA patients. These findings suggest that the TCO assists the quadriceps to reduce KFM and knee pain during stair descent. This is the first biomechanical evidence to support use of the TCO to reduce pain during an ADL that produces especially high knee forces and flexion moments. For any figures or tables, please contact the authors directly

INTRODUCTION. Osteoarthritis (OA) is a growing societal burden, due to the ageing population. Less invasive, less damaging, and cheaper methods for diagnosis are needed, and sound technology is an emerging tool in this field. Some studies investigate ultrasound signals, while others look at acoustic signals in the audible range. AIMS. The aim of the current research was to: 1) investigate the potential of visual scalogram analysis of Acoustic Emission (AE) frequencies within the human audible range (20–20000 Hz) to diagnose knee OA, 2) correlate the qualitative visual scalogram analysis of the AE with OA symptoms, and 3) to do this based on information gathered during gait. METHODS. The analysis was carried out on a database collected during a prospective sound study on healthy and osteoarthritic knees. Sound recordings obtained with a contact microphone mounted on the patella and attached to a digital pre-amplifier, whilst patients were walking on a treadmill, were visualised, manually sampled, and transformed into scalograms. Features of the scalograms were described and qualitatively analysed through chi-squared tests for association with healthy or OA knees (knee status), and with severity of OA pain and functional symptoms and impact on quality of life (QoL), activities of daily living (ADL) and sports using the Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales. RESULTS. 28 patients (56 knees) were included in the analysis. Our method provides a wide variety of different scalogram features: if no events were recorded, the scalogram was classified as ‘quiet’ (Fig 1). In case of abnormal recordings, data analysis evaluated association with the total count of the three most common events that appeared: 1. Peak (Fig 2), 2. Scattered (Fig 3) or 3. Island (localized noise but not presenting as a peak) (Fig 4) – “scalogram features”. No association was found between global scalogram characteristics (quiet versus ‘any noise’) and knee status (healthy or OA) (χ. 2. =3.163, p=0.075), but was found between knee status and three specific scalogram features (χ. 2. =9.743, p=0.008). The strongest association was a higher frequency of the “scattered” feature in the OA group (χ. 2. =9.06, p=0.01). Scalogram characteristics had no significant association with the sports and recreation (χ. 2. =1.74, p=0.419) nor the activities of daily living (χ. 2. =1.80, p=0.406) KOOS subscales. Significant association was found between scalogram characteristic and the pain (χ. 2. =10.34, p=0.006), quality of life (χ. 2. =6.58, p=0.037), and symptoms (χ. 2. =7.54, p=0.023) subscales. CONCLUSION. Promising results from analysis of individual features and of KOOS subscales establish the potential of acoustic analysis in evaluation of OA knees. More analysis of the data is needed to better define the variety of scalogram features. The future consequences of this research would be the development of a fast and affordable, non-invasive, radiation-free and potentially portable approach to evaluation, diagnosis and longitudinal monitoring of knee disorders. For any figures or tables, please contact the authors directly

Introduction. The sit-to-stand (STS) movement is a physically demanding activity of daily living and is performed more than 50 times per day in healthy adults. Several studies have shown that the normal ‘screw-home’ mechanism is altered after total knee arthroplasty (TKA). However, these studies have been criticized due to their limitations of the movement being non-weight-bearing or atypical daily activity (lunge maneuver). We analyzed TKA subjects during a STS activity to determine if the internal-external rotation of their TKA knees differed from the knees of control subjects. Materials and Methods. Six TKA subjects (3 M, 3 F) participated following institutional review board approval and informed consent. One subject had bilateral knee replacement. Surgery was performed by the same surgeon using the same type of implant (6 posterior-stabilized, 1 cruciate-retaining). The control group included eight healthy subjects (6 M, 2 F). Retro-reflective markers were placed over bony landmarks of the torso, pelvis, and lower extremities, and arrays of four markers were attached to the thighs and shanks using elastic wrap. A digitizing pointer was used to create virtual markers at the anterior superior iliac spines. A nine camera video-based opto-electronic system (Qualisys) was used for 3D motion capture. Subjects were barefoot and seated on a 46 cm armless bench with one foot on each force plate (AMTI). Subjects rose from their seated position, paused, and returned to the seated position at a self-selected pace repeatedly for 30 seconds. Subjects did not use their arms to push off the bench. Only the STS portion of the task was analyzed. The start of the STS cycle was defined when the C7 marker began to move forward in the sagittal plane and ended at the point of maximum knee extension. Only the right leg of the control subjects was used for analysis. Results. Femurs rotated internally as control subjects rose from the bench. Two of the TKA knees displayed a similar pattern of internal rotation as the knees extended. However, four TKA knees displayed the opposite pattern, and one TKA knee showed no rotation. For ease of comparison I/E rotation was normalized to zero at full extension (Figure 1). Discussion. Our results of a reverse tibio-femoral rotational pattern in TKA knees compared to normal knees are similar to those reported in fluoroscopic studies in which a single leg lunge activity is performed. Finding a similar reversal in STS is significant due to the necessity and frequency of the STS activity during daily living and warrants further investigation

At present, wear investigations of total hip replacement (THR) are performed in accordance with the ISO standard 14242, which is based on empirically determined relative motion data and exclusively describes the gait cycle. However, besides continuous walking, a number of additional activities characterize the movement sequences in everyday life and influence the wear rates as well as the size and shape of wear debris. Disagreements of in vitro and in vivo wear mechanisms seemed to be a result of differences between in vitro and in vivo kinematics and dynamics. This requires an optimization of the current test procedures and parameters. Hence, the aim of the present study was to evaluate most frequent activities of daily living, based on available in vivo data, in order to generate parameter sets according to loading and rotational movements close to the physiological situation. For the generation of angular patterns, time-dependent three-dimensional trajectories of reference points were used from the HIP98 database of Bergmann. The data set was evaluated and interpolated using analytical techniques to simulate consecutive smooth motion cycles in hip wear simulators or further test devices. The calculated relative joint movement was expressed by an ordered set of three elementary rotations and was complemented with three force components of the joint contact force to generate kinematically and dynamically consistent parameter sets. The obtained sets included the activities walking, knee bending, stair climbing and a combined load case of sitting down and standing up for an averaged patient. Generated slide tracks, created by the use of the angular patterns, demonstrated differences according to the kinematics between selected daily life activities and those established for the ISO standard 14242. In particular, for the relative flexion-extension rotational movement, routine activities showed significant higher ranges of motion. Additionally, the depicted force pattern underlined that the prevailing force component varied considerably between different activities. These deviations in range of motion and joint forces could be attributed to disagreements between in vitro and in vivo results of THR wear testing. The Integration of frequent activities of daily living in the in vivo test protocol could be realized by means of the sequential arrangement of the four investigated activities

INTRODUCTION. The benefits of combining enhanced recovery after surgery (ERAS) interventions with an outpatient THA/TKA program are uncertain. The primary objective was to compare adverse event rate and secondly to compare pain management, functional recovery, PROMs and patients' satisfaction. METHODS. We conducted an ambidirectional single subject cohort study on 48 consecutive patients who experienced both a standard-inpatient and an ERAS-outpatient THA/TKA (contralaterally). We compared complications according to Clavien-Dindo scale and Comprehensive Complications Index (CCI), and unplanned episodes of care. Postoperative pain assessed with a numeric rating scale, opioid consumption in morphine milligram equivalents, functional recovery, patient-reported outcome measures (WOMAC, KOOS, HOOS, Forgotten Joint Score and Patient Joint Perception) and patients' satisfaction were also evaluated. RESULTS. Following the ERAS-outpatient surgery, complication rates were reduced by more than 50% (2.1 vs 4.4, p<0.001), CCI was significantly lower (12.3 vs 19.1, p<0.001), and similar unplanned episodes of care were observed (p>0.999). In the first 8 postoperative hours, perceived pain was similar (p>0.805) while opioid consumption was significantly reduced with ERAS-outpatient care (9.3 vs 26.5 MME, p<0.001). Patients walked, climbed stairs, showered, performed activities of daily living, practised sports, went back to work sooner after ERAS-outpatient surgery (p<0.001), but PROMs were similar between groups at the last follow-up (p> 0.188). Patients were more satisfied with hospital stay, pain management, functional recovery, wound management, and overall experience of the ERAS-outpatient pathway and recommended it significantly more (p <0.002). DISCUSSION. Most studies comparing outpatient to inpatient programs conclude that outpatient surgeries did not increase complication or readmission rates, and, overall, were not inferior. We found that compared to std-inpatient practice, ERAS-outpatient program reduced complications by half while not resulting in more unplanned episodes of care. Moreover, it resulted in similar pain relief with fewer opioids, faster early functional recovery and higher satisfaction. Patients were significantly more inclined to recommend the ERAS-outpatient pathway after having personally experienced both outpatient and inpatient protocols. These finding are likely multifactorial and linked to the specific ERAS interventions. CONCLUSION. Results of this study highlight the importance of following ERAS principles when implementing an outpatient THA/TKA program