The orientation of the acetabular component is influenced not only by the orientation at which the surgeon implants the component, but also the orientation of the pelvis at the time of implantation. Hence, the orientation of the pelvis at set-up and its movement during the operation, are important. During 67 hip replacements, using a validated photogrammetric technique, we measured how three surgeons orientated the patient’s pelvis, how much the pelvis moved during surgery, and what effect these had on the final orientation of the acetabular component. Pelvic orientation at set-up, varied widely (mean (± 2, standard deviation (. sd. ))): tilt 8° (2. sd . ±32), obliquity –4° (2. sd . ±12), rotation –8° (2. sd . ±14). Significant differences in pelvic positioning were detected between surgeons (p < 0.001). The mean angular movement of the pelvis between set-up and component implantation was 9° (. sd. 6). Factors influencing pelvic movement included surgeon, approach (posterior >  lateral), procedure (hip resurfacing > total hip replacement) and type of support (p < 0.001). Although, on average, surgeons achieved their desired acetabular component orientation, there was considerable variability (2. sd. ±16) in component orientation. We conclude that inconsistency in positioning the patient at set-up and movement of the pelvis during the operation account for much of the variation in acetabular component orientation. Improved methods of positioning and holding the pelvis are required. Cite this article: Bone Joint J 2014; 96-B:876–83

Patients with osteoarthritis (OA) of the knee commonly alter their movement to compensate for deficiencies. This study presents a new numerical procedure for classifying sit-to-walk (STW) movement strategies. Ten control and twelve OA participants performed the STW task in a motion capture laboratory. A full body biomechanical model was used. Participants were instructed to sit in a comfortable self-selected position on a stool height adjusted to 100% of their knee height and then stand and pick up an object from a table in front of them. Three matrices were constructed defining the progression of the torso, feet and hands in the sagittal plane along with a fourth expressing the location of the hands relative to the knees. Hierarchical clustering (HC) was used to identify different strategies. Trials were also classified as to whether the left (L) and right (R) extremities used a matching strategy (bilateral) or not (asymmetrical). Fisher's exact test was used to compare this between groups. Clustering of the torso matrix dichotomised the trials in two major clusters; subjects leaning forward (LF) or not. The feet and hands matrices revealed sliding the foot backward (FB) and moving an arm forward (AF) strategies respectively. Trials not belonging in the AF cluster were submitted to the last HC of the fourth matrix exposing three additional strategies, the arm pushing through chair (PC), arm pushing through knee (PK) and arm not used (NA). The control participants used the LF+FBR+PK combination most frequently whereas the OA participants used the AFR+PCL. OA patients used significantly more asymmetrical arm strategies, p=0.034. The results demonstrated that control and OA participants favour different STW strategies. The OA patients asymmetrical arm behaviour possibly indicates compensating for weakness of the affected leg. These strategy definitions may be useful to assess post-operative outcomes and rehabilitation progress

Digital Ventilated Cages (DVC) offer an innovative technology to obtain accurate movement data from a single mouse over time [1]. Thus, they could be used to determine the occurrence of a tendon damage event as well as inform on tissue regeneration [2,3]. Therefore, using the mouse model of tendon experimental damage, in this study it has been tested whether the recovery of tissue microarchitecture and of extracellular matrix (ECM) correlates with the motion data collected through this technology. Mice models were used to induce acute injury in Achilles tendons (ATs), while healthy ones were used as control. During the healing process, the mice were housed in DVC cages (Tecniplast) to monitor animal welfare and to study biomechanics assessing movement activity, an indicator of the recovery of tendon tissue functionality. After 28 days, the AT were harvested and assessed for their histological and immunohistochemical properties to obtain a total histological score (TSH) that was then correlated to the movement data. DVC cages showed the capacity to distinguish activity patterns in groups from the two different conditions. The data collected showed that the mice with access to the mouse wheel had a higher activity as compared to the blocked wheel group, which suggests that the extra movement during tendon healing improved motion ability. The histological results showed a clear difference between different analyzed groups. The bilateral free wheel group showed the best histological recovery, offering the highest TSH score, thus confirming the results of the DVC cages and the correlation between movement activity and structural recovery. Data obtained showed a correlation between TSH and the DVC cages, displaying structural and movement differences between the tested groups. This successful correlation allows the usage of DVC type cages as a non-invasive method to predict tissue regeneration and recovery. Acknowledgements: This research is part of the P4FIT project ESR13, funded by the H2020-ITN-EJD MSCA grant agreement No.955685

Purpose: The deleterious effects of blocking movement of normal joints has been demonstrated by numerous animal experiments and clinical observations. Conversely, mobilisation of the joints leads to metabolic and trophic effects commonly attributed to changes in the nutritional status of the cartilage. In vitro experiments and mechanobiological studies have however suggested that more fundamental mechanisms are operating, demonstrating the impact of physical factors on biological cell regulation and tissue organisation. The purpose of our experimentation was to study the biological effects of movement on a model of skeletal regeneration from mesenchymatous tissue. The tested hypothesis was that movement crossing a living tissue causes the emission of specific signals which contribute to its anatomic and functional organisation. Material and methods: We used 27 immature rabbits for the model. We transferred a vascularised periosteal flap to the knee region in order to initiate a process of skeletal tissue regeneration. The regenerated tissue was submitted to joint movements caused by the animal’s spontaneous movements. In the first group of animals, the knee was left intact. In the second group, 25 mm of the distal femur was removed, including the condyles. Tissue regeneration was compared with that obtained without joint movement. Results: Qualitative changes in regenerated tissue were found to be influenced by movement. The differentiation of the mesenchymatous precursors was oriented towards production of cartilage and fibrocartilage. In the group with a sectioned femur, a mobile cartilage joint space was obtained at the interface between the regenerated femur and the tibia. A functional neo-joint was formed. Discussion: This model of tissue regeneration, similar to that observed in experimental nonunion, demonstrated the contribution of multipotent stem cells of diverse origins. Joint mobility and its mechanical consequences produced information which were perceived as a modification of the environment. They regulated the differentiation of pluripotent cell elements and thus guided the spatial and temporal organisation of in vivo tissue repair processes. Conclusion: Our results confirm the major influence of mechanical constraints on the organisation of skeletal tissue. The effect is expressed by the remodelling of mature tissues, but is also observed in immature tissues implicated in morphogenesis and skeletal regeneration processes. The transduction mechanisms remain to be described. However, the results obtained for cartilage regeneration demonstrate the practical interest of periosteal arthroplasty. Further improvement of the model to optimise continuous passive movement would open new perspectives for in vivo joint regeneration

Purpose and Background. Work-related musculoskeletal disorders (WRMSD) can affect 56–80% of physiotherapists. Patient handling is reported as a significant risk factor for developing WRMSD with the back most frequently injured. Physiotherapists perform therapeutic handling to manually assist and facilitate patients’ movement to aid rehabilitation, which can increase physiotherapists risk of experiencing high forces during patient handling. Methods and Results. A descriptive cross-sectional study was completed to explore and quantitatively measure the movement of ten physiotherapists during patient handling, over one working day, in a neurological setting. A wearable 3-dimensional motion analysis system, Xsens (Movella, Henderson, NV), was used to measure physiotherapist movement and postures in the ward setting during patient treatment sessions. The resulting joint angles were reported descriptively and compared against a frequently used ergonomic assessment tool, the Rapid Upper Limb Assessment (RULA). Physiotherapists adopted four main positions during patient handling tasks: 1) kneeling; 2) half-kneeling; 3) standing; and 4) sitting. Eight patient handling tasks were identified and described: 1) Lie-to-sit; 2) sit-to-lie; 3) sit-to-stand; facilitation of 4) upper limb; 5) lower limb; 6) trunk; and 7) standing treatments; and 8) walking facilitation. Kneeling and sitting positions demonstrated greater neck extension and greater lumbosacral flexion during treatments which scores highly with the RULA. Conclusion. This research identified that patient treatment tasks were more often performed in kneeling or sitting positions than standing. Current moving and handling guidance teaches moving and handling in a standing position; loading and stresses experienced by the physiotherapists may differ in sitting or kneeling positions. Conflicts of interest. None. Sources of funding. None. This work has been presented as a poster at the CSP conference Glasgow 2023

Aims. Few reports compare the contribution of the talonavicular articulation to overall range of movement in the sagittal plane after total ankle arthroplasty (TAA) and tibiotalar arthrodesis. The purpose of this study was to assess changes in ROM and functional outcomes following tibiotalar arthrodesis and TAA. Patients and Methods. Patients who underwent isolated tibiotalar arthrodesis or TAA with greater than two-year follow-up were enrolled in the study. Overall arc of movement and talonavicular movement in the sagittal plane were assessed with weight-bearing lateral maximum dorsiflexion and plantarflexion radiographs. All patients completed Short Form-12 version 2.0 questionnaires, visual analogue scale for pain (VAS) scores, and the Foot and Ankle Ability Measure (FAAM). Results. In all, 41 patients who underwent TAA and 27 patients who underwent tibiotalar arthrodesis were enrolled in the study. The mean total arc of movement was 34.2° (17.0° to 59.1°) with an average contribution from the talonavicular joint of 10.5° (1.2° to 28.8°) in the TAA cohort. The average total arc of movement was 24.3° (6.9° to 44.3°) with a mean contribution from the talonavicular joint of 22.8° (5.6° to 41.4°) in the arthrodesis cohort. A statistically significant difference was detected for both total sagittal plane movement (p = 0.00025), and for talonavicular motion (p < 0.0001). A statistically significant lower VAS score (p = 0.0096) and higher FAAM (p = 0.01, p = 0.019, respectively) was also detected in the TAA group. Conclusion. TAA preserves more anatomical movement, has better pain relief and better patient-perceived post-operative function compared with patients undergoing fusion. The relative increase of talonavicular movement in fusion patients may play a role in the outcomes compared with TAA and may predispose these patients to degenerative changes over time. Take home message: TAA preserves more anatomic sagittal plane motion and provides greater pain relief and better patient-perceived outcomes compared with ankle arthrodesis. Cite this article: Bone Joint J 2016;98-B:634–40

We have previously reported on the medium-term outcomes following a non-operative protocol of a short period of splinting followed by early movement to treat simple dislocations of the elbow. We undertook extended follow up of our original patient study group to determine whether the excellent results previously reported were maintained in the very long-term. A secondary question was to determine the rate and need for any late surgical intervention. We attempted to contact all patients in the original patient study group. Patients were requested to complete the Oxford elbow score (OES), the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire and a validated patient satisfaction questionnaire. Patients were requested to attend a face-to-face assessment where they underwent a clinical examination including neurovascular assessment, range-of-motion and an assessment of ligamentous stability. Seventy-one patients (65%) from the original patient study group agreed to participate in the study. The mean duration of follow-up was 19.3 years. At final follow-up patients reported excellent functional outcome scores and a preserved functional range of movement in the injured elbows. The mean DASH score was 5.22 points and the mean Oxford Elbow Score was 91.6 points. The mean satisfaction score was 90.9 points. Our study shows that the excellent outcomes following treatment with a protocol of a short period of splinting and early movement remain excellent and are maintained into the very long term. These findings support our hypothesis that this treatment protocol is appropriate and suitable for most patients with simple dislocations of the elbow. The role for primary ligamentous repair for this patient group should be carefully considered. Work to more clearly define the anticipated benefits of surgery for specific patient groups or injury patterns would help to support informed decision making

Technological advancements in orthopaedic surgery have mainly focused on increasing precision during the operation however, there have been few developments in post-operative physiotherapy. We have developed a computer vision program using machine learning that can virtually measure the range of movement of a joint to track progress after surgery. This data can be used by physiotherapists to change patients’ exercise regimes with more objectively and help patients visualise the progress that they have made. In this study, we tested our program's reliability and validity to find a benchmark for future use on patients. We compared 150 shoulder joint angles, measured using a goniometer, and those calculated by our program called ArmTracking in a group of 10 participants (5 males and 5 females). Reliability was tested using adjusted R squared and validity was tested using 95% limits of agreement. Our clinically acceptable limit of agreement was ± 10° for ArmTracking to be used interchangeably with goniometry. ArmTracking showed excellent overall reliability of 97.1% when all shoulder movements were combined but there were lower scores for some movements like shoulder extension at 75.8%. There was moderate validity shown when all shoulder movements were combined at 9.6° overestimation and 18.3° underestimation. Computer vision programs have a great potential to be used in telerehabilitation to collect useful information as patients carry out prescribed exercises at home. However, they need to be trained well for precise joint detections to reduce the range of errors in readings

Objectives. The objective of this study was to quantify the relative movement between the articular surfaces in the tibiotalar and subtalar joints during normal walking in asymptomatic individuals. Methods. 3D movement data of the ankle joint complex were acquired from 18 subjects using a biplanar fluoroscopic system and 3D-to-2D registration of bone models obtained from CT images. Surface relative velocity vectors (SRVVs) of the articular surfaces of the tibiotalar and subtalar joints were calculated. The relative movement of the articulating surfaces was quantified as the mean relative speed (RS) and synchronization index (SI. ENT. ) of the SRVVs. Results. SI. ENT. and mean RS data showed that the tibiotalar joint exhibited translational movement throughout the stance, with a mean SI. ENT. of 0.54 (. sd. 0.21). The mean RS of the tibiotalar joint during the 0% to 20% post heel-strike phase was 36.0 mm/s (. sd. 14.2), which was higher than for the rest of the stance period. The subtalar joint had a mean SI. ENT. value of 0.43 (. sd. 0.21) during the stance phase and exhibited a greater degree of rotational movement than the tibiotalar joint. The mean relative speeds of the subtalar joint in early (0% to 10%) and late (80% to 90%) stance were 23.9 mm/s (. sd. 11.3) and 25.1 mm/s (. sd 9.5). , respectively, which were significantly higher than the mean RS during mid-stance (10% to 80%). Conclusion. The tibiotalar and subtalar joints exhibited significant translational and rotational movement in the initial stance, whereas only the subtalar joint exhibited significant rotational movement during the late stance. The relative movement on the articular surfaces provided deeper insight into the interactions between articular surfaces, which are unobtainable using the joint coordinate system. Cite this article: C-B. Phan, D-P. Nguyen, K. M. Lee, S. Koo. Relative movement on the articular surfaces of the tibiotalar and subtalar joints during walking. Bone Joint Res 2018;7:501–507. DOI: 10.1302/2046-3758.78.BJR-2018-0014.R1

For clinical movement analysis, optical marker-based motion capture is the gold standard. With the advancement of AI-driven computer vision, markerless motion capture (MMC) has emerged. Validity against the marker-based standard has only been examined for lightly-dressed subjects as required for marker placement. This pilot study investigates how different clothing affects the measurement of typical gait metrics. Gait tests at self-selected speed (4 km/h) were performed on a treadmill (Motek Grail), captured by 9 cameras (Qualisys Miqus, 720p, f=100Hz) and analyzed by a leading MMC application (Theia, Canada). A healthy subject (female, h=164cm, m=54kg) donned clothes between trials starting from lightly dressed (LD: bicycle tight, short-sleeved shirt), adding a short skirt (SS: hip occlusion) or a midi-skirt (MS: partial knee occlusion) or street wear (SW: jeans covering ankle, long-sleeved blouse), the lattern combined with a short jacket (SWJ) or a long coat (SWC). Gait parameters (mean±SD, t=10s) calculated (left leg, mid-stance) were ankle pronation (AP-M), knee flexion (KF-M), pelvic obliquity (PO-M) and trunk lateral lean (TL-M) representing clinically common metrics, different joints and anatomic planes. Four repetitions of the base style (LD) were compared to states of increased garment coverage using the t-test (Bonferroni correction). For most gait metrics, differences between the light dress (LD) and various clothing styles were absent (p>0.0175), small (< 2SD) or below the minimal clinically important differences (MCID). For instance, KF-M was for LD=10.5°±1.7 versus MD=12.0°±0.5 (p=0.07) despite partial knee cover. AP-M measured for LD=5.2°±0.6 versus SW=4.1°±0.7 (p<0.01) despite ankle cover-up. The difference for KF-M between LD=10.5°±1.7 versus SWL=6.0°±0.9, SW and SWJ (7.6°±1.5, p<0.01) indicates more intra-subject gait variability than clothing effect. This study suggests that typical clothings styles only have a small clinically possibly negligible effect on common gait parameters measured with MMC. Thus, patients may not need to change clothes or be instructed to wear specific garments. In addition to avoiding marker placement, this further increases speed, ease and economy of clinical gait analysis with MMC facilitating high volume or routine application

Mechanical loading of joints with osteoarthritis (OA) results in pain-related functional impairment, altered joint mechanics and physiological nociceptor interactions leading to an experience of pain. However, the current tools to measure this are largely patient reported subjective impressions of a nociceptive impact. A direct measure of nociception may offer a more objective indicator. Specifically, movement-induced physiological responses to nociception may offer a useful way to monitor knee OA. In this study, we gathered preliminary data on healthy volunteers to analyse whether integrated biomechanical and physiological sensor datasets could display linked and quantifiable information to a nociceptive stimulus. Following ethical approval, 15 healthy volunteers completed 5 movement and stationary activities in 2 conditions; a control setting and then repeated with an applied quantified thermal pain stimulus to their right knee. An inertial measurement unit (IMU) and an electromyography (EMG) lower body marker set were tested and integrated with ground reaction force (GRF) data collection. Galvanic skin response electrodes for skin temperature and conductivity and photoplethysmography (PPG) sensors were manually timestamped to the integrated system. Pilot data showed EMG, GRF and IMU fluctuations within 0.5 seconds of each other in response to a thermal trigger. Preliminary analysis on the 15 participants tested has shown skin conductance, PPG, EMG, GRFs, joint angles and kinematics with varying increases and fluctuations during the thermal condition in comparison to the control condition. Preliminary results suggest physiological and biomechanical data outputs can be linked and identified in response to a defined nociceptive stimulus. Study data is currently founded on healthy volunteers as a proof-of-concept. Further exploratory statistical and sensor readout pattern analysis, alongside early and late-stage OA patient data collection, can provide the information for potential development of wearable nociceptive sensors to measure disease progression and treatment effectiveness

Non-operative management of displaced olecranon fractures in elderly low demand patients is reported to result in a satisfactory outcome despite routinely producing a nonunion. The aim of this study was to assess whether there is evidence of dynamic movement of the fracture fragment during the elbow arc of movement. Five consecutive patients (≥70 years of age) with a displaced olecranon fracture (Mayo 2A) that were managed with non-operative intervention were recruited. All underwent ultrasound evaluation at six weeks and follow-up questionnaires at six months including the DASH and Oxford Elbow Score (OES). There were three women and two men with a mean age of 79yrs (range 70–88). All injuries were sustained following a fall from standing height. The mean fracture gap in extension was 22.5mm (95% CI 13.0–31.9), midflexion 21.8mm (11.6–32.0) and in deep flexion 21.8mm (10.9–32.8). Although the amount of fracture displacement varied between patients, it remained static in each patient with no significant differences observed throughout the arc of motion (ANOVA p=0.99). The six-month median DASH score was 7.5 (IQR range, 4.2–39.3) and the OES was 44.0 (29.0–47.5). Four out of the five patients were satisfied with their function. Ultrasound evaluation of displaced olecranon fractures following non-operative management suggests the proximal fragment may function as a sesamoid type bone within the triceps sleeve. This could explain how a functional arc of movement with a minimum level of discomfort can usually be expected with non-operative management in select patients

INTRODUCTION. In living normal knee the lateral femoral condyle rolls posteriorly more than the medial side to the extent that in deep flexion the lateral femoral condyle sublux from the tibial surface (Nakagawa et al). The purpose of this presentation is to study the tibiofemoral movement in patients who had full flexion after total knee replacements and to compare it with that of normal knee. MATERIALS AND METHODS. 23 knees were scanned using SIEMENS SIREMOBILE Iso-C with 3D Extension C-arm. The system is able reconstruct 3D images that can be viewed from deferent angle and precise measurements of distances between the deferent components of the implant can be made. The knee was scanned while the patient is sitting in kneeling position with the calf touching the thigh (flexion of over 150 degree). RESULTS. All the cases studied showed a variable roll back between the medial and lateral femoral condyle. In all cases the lateral roll back was much more than the medial. In 14 cases we confirmed lateral condyle subluxation similar to what is seen in normal knee. The position of the foot (internal or external rotation) during scanning did not affect the lateral femoral condyle role back. DISCUSSION. Although previous studies have shown paradoxical types of tibiofemoral movement in patients who have total knee replacements throughout the range of movement, the knees in patients who had full flexion after TKA tend to have the same tibiofemoral movement as the normal knee in deep flexion. The lateral femoral condyles spin off or subluxation could adversely affect the implant components especially if the design does not accommodate this movement. CONCLUSION. The lateral femoral condyle may sublux from the tibia during kneeling in patients who had full flexion after TKA. These findings should call for changes in the implant design to accommodate the lateral condyle roll back

Construction of a functional skeleton is accomplished through co-ordination of the developmental processes of chondrogenesis, osteogenesis, and synovial joint formation. Infants whose movement in utero is reduced or restricted and who subsequently suffer from joint dysplasia (including joint contractures) and thin hypo-mineralised bones, demonstrate that embryonic movement is crucial for appropriate skeletogenesis. This has been confirmed in mouse, chick, and zebrafish animal models, where reduced or eliminated movement consistently yields similar malformations and which provide the possibility of experimentation to uncover the precise disturbances and the mechanisms by which movement impacts molecular regulation. Molecular genetic studies have shown the important roles played by cell communication signalling pathways, namely Wnt, Hedgehog, and transforming growth factor-beta/bone morphogenetic protein. These pathways regulate cell behaviours such as proliferation and differentiation to control maturation of the skeletal elements, and are affected when movement is altered. Cell contacts to the extra-cellular matrix as well as the cytoskeleton offer a means of mechanotransduction which could integrate mechanical cues with genetic regulation. Indeed, expression of cytoskeletal genes has been shown to be affected by immobilisation. In addition to furthering our understanding of a fundamental aspect of cell control and differentiation during development, research in this area is applicable to the engineering of stable skeletal tissues from stem cells, which relies on an understanding of developmental mechanisms including genetic and physical criteria. A deeper understanding of how movement affects skeletogenesis therefore has broader implications for regenerative therapeutics for injury or disease, as well as for optimisation of physical therapy regimes for individuals affected by skeletal abnormalities. Cite this article: Bone Joint Res 2015;4:105–116

Aim. To quantify the micro-motion at the fracture gap in a tibial fracture model stabilised with an external fixator. Method. A surrogate model of a tibia and a cadaver leg were fractured and stabilised using a two-ring hexapod external fixator. They were tested initially under static loading and then subjected to vibration. Results. The overall stiffness of the cadaver leg was significantly higher than the surrogate model under static loading. This resulted in a significantly higher facture movement in the surrogate model. In the surrogate model there was no significant difference between the displacement applied via the vibrating platform and the fracture movement at the fracture gap. The fracture movement was however found to be statistically lower during vibration in the cadaver leg. Discussion. The significant difference in stiffness seen between the surrogate and cadaveric model is likely due to multiple factors such as the presence of soft tissues and fibula, including the biomechanical differences between the frame constructs. The fracture movement seen at 200N loading in the cadaveric leg was approximately 1mm which corresponds to partial weight bearing and a displacement shown to promote callus formation. During vibration however, the movements were far less suggesting that micromotion would be insufficient to promote healing. It may be proposed that soft tissues can alter the overall stiffness and fracture movement recorded in biomechanical studies investigating the effect of various devices or therapies

Cervical spinal arthrodesis is the standard of care for the treatment of spinal diseases induced neck pain. However, adjacent segment disease (ASD) is the primary postoperative complication, which draws great concerns. At present, controversy still exists for the etiology of ASD. Knowledge of cervical spinal loading pattern after cervical spinal arthrodesis is proposed to be the key to answer these questions. Musculoskeletal (MSK) multi-body dynamics (MBD) models have an opportunity to obtain spinal loading that is very difficult to directly measure in vivo. In present study, a previously validated cervical spine MSK MBD model was developed for simulating cervical spine after single-level anterior arthrodesis at C5-C6 disc level. In this cervical spine model, postoperative sagittal alignment and spine rhythms of each disc level, different from normal healthy subject, were both taken into account. Moreover, the biomechanical properties of facet joints of adjacent levels after anterior arthrodesis were modified according to the experimental results. Dynamic full range of motion (ROM) flexion/extension simulation was performed, where the motion data after arthrodesis was derived from published in-vivo kinematic observations. Meanwhile, the full ROM flexion/extension of normal subject was also simulated by the generic cervical spine model for comparative purpose. The intervertebral compressive and shear forces and loading-sharing distribution (the proportions of intervertebral compressive and shear force and facet joint force) at adjacent levels (C3-C4, C4-C5 and C6-C7 disc levels) were then predicted. By comparison, arthrodesis led to a significant increase of adjacent intervertebral compressive force during the head extension movement. Postoperative intervertebral compressive forces at adjacent levels increased by approximate 20% at the later stage of the head extension movement. However, there was no obvious alteration in adjacent intervertebral compressive force, during the head flexion movement. For the intervertebral shear forces in the anterior-posterior direction, no significant differences were found between the arthrodesis subject and normal subject, during the head flexion/extension movement. Meanwhile, cervical spinal loading-sharing distribution after anterior arthrodesis was altered compared with the normal subject's distribution, during the head extension movement. In the postoperative loading-sharing distribution, the percentage of intervertebral disc forces was further increased as the motion angle increased, compared with normal subject. In conclusion, cervical spinal loading after anterior arthrodesis was significantly increased at adjacent levels, during the head extension movement. Cervical spine musculoskeletal MBD model provides an attempt to comprehend postoperative ASD after anterior arthrodesis from a biomechanical perspective

Objectives. To elucidate the effects of age on the expression levels of the receptor activator of the nuclear factor-κB ligand (RANKL) and osteoclasts in the periodontal ligament during orthodontic mechanical loading and post-orthodontic retention. Materials and Methods. The study included 20 male Sprague-Dawley rats, ten in the young group (aged four to five weeks) and ten in the adult group (aged 18 to 20 weeks). In each rat, the upper-left first molar was subjected to a seven-day orthodontic force loading followed by a seven-day retention period. The upper-right first molar served as a control. The amount of orthodontic tooth movement was measured after seven-day force application and seven-day post-orthodontic retention. The expression levels of RANKL and the tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts were evaluated on day 7 (end of mechanical force loading) and day 14 (after seven days of post-orthodontic retention). Statistical analysis was performed using the t-test, and significance was set at p < 0.05. Results. There was no significant difference between the amount of tooth movement in the young group (0.96, standard deviation (. sd. ) 0.30mm) and that in the adult group (0.80mm, . sd. 0.28) (p > 0.05) after the seven-day force application. On the compression side, the expression of RANKL and TRAP-positive osteoclasts in both the young and the adult groups increased after the application of force for seven days, and then decreased at the end of the seven-day retention period. However, by the end of the period, the expression of RANKL on the compression side dropped to the control level in the young group (p > 0.05), while it was still higher than that on the control side in the adult group (p < 0.05). The expression of RANKL on the compression side did not show significant difference between the young and the adult groups after seven-day force application (p > 0.05), but it was significantly higher in the adult group than that in the young group after seven-day post-orthodontic retention (p < 0.05). Similarly, the decreasing trend of TRAP-positive osteoclasts during the retention period in the adult group was less obvious than that in the young group. Conclusions. The bone-resorptive activity in the young rats was more dynamic than that in the adult rats. The expression of RANKL and the number of osteoclasts in adult rats did not drop to the control level during the post-orthodontic retention period while RANKL expression and the number of osteoclasts in young rats had returned to the baseline. Cite this article: X. Li, M. Li, J. Lu, Y. Hu, L. Cui, D. Zhang, Y. Yang. Age-related effects on osteoclastic activities after orthodontic tooth movement. Bone Joint Res 2016;5:492–499. DOI: 10.1302/2046-3758.510.BJR-2016-0004.R2

Objectives. To date, no study has considered the impact of acromial morphology on shoulder range of movement (ROM). The purpose of our study was to evaluate the effects of lateralization of the centre of rotation (COR) and neck-shaft angle (NSA) on shoulder ROM after reverse shoulder arthroplasty (RSA) in patients with different scapular morphologies. Methods. 3D computer models were constructed from CT scans of 12 patients with a critical shoulder angle (CSA) of 25°, 30°, 35°, and 40°. For each model, shoulder ROM was evaluated at a NSA of 135° and 145°, and lateralization of 0 mm, 5 mm, and 10 mm for seven standardized movements: glenohumeral abduction, adduction, forward flexion, extension, internal rotation with the arm at 90° of abduction, as well as external rotation with the arm at 10° and 90° of abduction. Results. CSA did not seem to influence ROM in any of the models, but greater lateralization achieved greater ROM for all movements in all configurations. Internal and external rotation at 90° of abduction were impossible in most configurations, except in models with a CSA of 25°. Conclusion. Postoperative ROM following RSA depends on multiple patient and surgical factors. This study, based on computer simulation, suggests that CSA has no influence on ROM after RSA, while lateralization increases ROM in all configurations. Furthermore, increasing subacromial space is important to grant sufficient rotation at 90° of abduction. In summary, increased lateralization of the COR and increased subacromial space improve ROM in all CSA configurations. Cite this article: A. Lädermann, E. Tay, P. Collin, S. Piotton, C-H Chiu, A. Michelet, C. Charbonnier. Effect of critical shoulder angle, glenoid lateralization, and humeral inclination on range of movement in reverse shoulder arthroplasty. Bone Joint Res 2019;8:378–386. DOI: 10.1302/2046-3758.88.BJR-2018-0293.R1

Introduction: The Lachman test for anterior cruciate ligament (ACL) deficiency, requires a subjective assessment of joint movement, as the tibia is pulled anteriorly. This study has objectively quantified this movement using a magnetic tracking device. Materials and Methods: Ten patients aged 21 to 51 years were assessed as having unilateral ACL deficiency with conventional clinical tests. These patients were then reassessed using a magnetic tracking device (Polhemus Fastrak). Patients had magnetic sensors attached around the femoral and tibial mid-shafts using elasticated Velcro straps. The Lachman test was then performed with the patient lying within range of the system’s magnetic source. The test was performed three times on the normal and injured knees of each patient. During the tests, sensor position and orientation data was collected with an accuracy better than 1 mm and 1 degree, respectively. The data was sampled at 10Hz and stored on a computer for post-test analysis. This analysis deduced the tibial displacement resulting from each Lachman pull. Results: The main Lachman movement is an anterior displacement of the tibia with respect to the femur. The mean anterior movement for the normal knees was 5.6 mm (SD=2.5). By comparison the ACL deficient knees had a mean anterior movement of 10.2 mm (SD=4.2). This is 82 % more. A paired t test of this data showed it to be highly significant with P = 0.005. In addition to the anterior movement, there was also a small proximal tibial movement. In the normal knees the mean movement was 0.7 mm (SD=1.9). In the injured knees the mean movement was 2.1 mm (SD=3.4). However, this difference was not significant (P = 0.12). Conclusion: This study has quantified the movement produced during the Lachman test for ACL deficiency. The results compare well with reported results from similar arthrometer tests[. 1. ]. The main advantage of the magnetic tracker is that its lightweight sensors cause minimal disturbance to the established clinical test. It therefore offers a convenient and non-invasive method of investigation

Ankle sprains are very common, and usually tear or partly tear one or more of the ligaments on the outer side of the ankle. The ankle joint is only designed to move up and down, whereas there is another joint immediately below the ankle joint, called the subtalar joint, which is designed to do the tilting in and out movement. If the foot tilts over too far, the subtalar joint reaches the end of its movement and then the ankle ligaments stretch and tear. It is possible that variations of subtalar range of movement may contribute to ankle sprains or symptoms of weakness or instability. In particular, if the subtalar joint is unusually restricted in its movement, then the foot does not have to tilt far before the lateral ligaments tear. If on the other hand the subtalar joint is particularly mobile and has excessive movement, then the foot may go right over without actually tearing ligaments and feel insecure or unstable simply as a result of abnormal excessive movement. Recent studies have demonstrated what we have always suspected, that clinical examination and assessment of subtalar range of movement is highly unreliable. In order to accurately assess whether your subtalar range of movement is unusually restricted or excessive, the only standard and accurate method to date has been to obtain a CT scan. We are now undertaking a study to establish whether plain xrays with a small metal clamp applied to the heel might not be a simpler, cheaper, quicker and equally reliable method of assessment of subtalar movement. If you would like to know if your subtalar movement might be a contributing factor to either stiffness or insecurity of your ankle, we invite you to be examined clinically, by plain xrays at SPORTSMED•SA, and by a CT scan at Jones & Partners Radiology at Burnside. The xray and CT investigations would be bulk billed under Medicare so that you would not incur any personal cost and the information could well be helpful in assessing your ankle problem, or at least be reassuring that the subtalar joint has a normal range of movement. The investigations can be arranged through your treating doctor, physiotherapist or podiatrist or by contacting Dr Roger Paterson, Foot and Ankle Surgeon, or Mr Stephen Landers, his Research Assistant, on Ph: 8362 7788. The CT scan would be a very limited investigation resulting in minimum radiation exposure, comparable to the normal xrays. Further information on what is involved in having a CT scan is attached. Neither the CT scan nor the plain xrays should cause any more than minor discomfort as the foot is tilted through its full range of movement, or from the padded pressure of the G clamp. SPORTSMED•SA remains committed to excellence in treating active people of all ages, and through these investigations, we plan to further enhance the quality of assessment and care of people who suffer ankle problems