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

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

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 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

Objective: To evaluate the impact of soft tissue release on range of movement following total knee replacement. Methods: Sixty four patients underwent PFC sigma total knee replacement through a medial arthrotomy. Range of active movement was measured preoperatively, and maximal flexion was measured after implantation, using the drop test while the patient was under anaesthetic. Soft tissue release was graded from 1 to 5, depending on the structures released. Range of movement was correlated with extent of soft tissue release, to see if release had any impact on increase in range of movement. Results: All patients had an improvement in range of movement following surgery. Post operative range of movement correlated strongly with preoperative ROM. Patients requiring extensive releases tended to have less preoperative ROM, but the gain was independent of medial release. Those requiring extensive posterior release had poorer preoperative movement, and significantly less improvement. In those requiring an extensive medial release, a posterior release improved gain in ROM. Conclusion: Postoperative ROM following TKR is independent of extent of medial release. In patients requiring extensive medial release, a posterior release improves gain in movement

Objective: To evaluate the impact of soft tissue release on range of movement following total knee replacement. Methods: Sixty four patients underwent next-gen (Zimmer) posterior stabilising total knee replacement through a medial arthrotomy. Range of active movement was measured preoperatively, and maximal flex-ion was measured after implantation, using the drop test while the patient was under anaesthetic. Soft tissue release was graded from 1 to 5, depending on the structures released. Range of movement (ROM) was correlated with extent of soft tissue release, to see if release had any impact on increase in range of movement. Results: All patients had an improvement in range of movement following surgery. Post operative range of movement correlated strongly with preoperative ROM. Patients requiring extensive releases tended to have less preoperative ROM, but the gain was independent of medial release. Those requiring extensive posterior release had poorer preoperative movement, and significantly less improvement. In those requiring an extensive medial release, a posterior release improved gain in ROM. Conclusion: Postoperative ROM following TKR is independent of extent of medial release. In patients requiring extensive medial release, a posterior release improves gain in movement

Aims. This study aimed to determine the minimal detectable change (MDC), minimal clinically important difference (MCID), and substantial clinical benefit (SCB) under distribution- and anchor-based methods for the Mayo Elbow Performance Index (MEPI) and range of movement (ROM) after open elbow arthrolysis (OEA). We also assessed the proportion of patients who achieved MCID and SCB; and identified the factors associated with achieving MCID. Methods. A cohort of 265 patients treated by OEA were included. The MEPI and ROM were evaluated at baseline and at two-year follow-up. Distribution-based MDC was calculated with confidence intervals (CIs) reflecting 80% (MDC 80), 90% (MDC 90), and 95% (MDC 95) certainty, and MCID with changes from baseline to follow-up. Anchor-based MCID (anchored to somewhat satisfied) and SCB (very satisfied) were calculated using a five-level Likert satisfaction scale. Multivariate logistic regression of factors affecting MCID achievement was performed. Results. The MDC increased substantially based on selected CIs (MDC 80, MDC 90, and MDC 95), ranging from 5.0 to 7.6 points for the MEPI, and from 8.2° to 12.5° for ROM. The MCID of the MEPI were 8.3 points under distribution-based and 12.2 points under anchor-based methods; distribution- and anchor-based MCID of ROM were 14.1° and 25.0°. The SCB of the MEPI and ROM were 17.3 points and 43.4°, respectively. The proportion of the patients who attained anchor-based MCID for the MEPI and ROM were 74.0% and 94.7%, respectively; furthermore, 64.2% and 86.8% attained SCB. Non-dominant arm (p = 0.022), higher preoperative MEPI rating (p < 0.001), and postoperative visual analogue scale pain score (p < 0.001) were independent predictors of not achieving MCID for the MEPI, while atraumatic causes (p = 0.040) and higher preoperative ROM (p = 0.005) were independent risk factors for ROM. Conclusion. In patients undergoing OEA, the MCID for the increased MEPI is 12.2 points and 25° increased ROM. The SCB is 17.3 points and 43.3°, respectively. Future studies using the MEPI and ROM to assess OEA outcomes should report not only statistical significance but also clinical importance. Cite this article: Bone Joint J 2021;103-B(2):366–372

Aims. This study aims to evaluate a new home medical stretching device called the Self Treatment Assisted Knee (STAK) tool to treat knee arthrofibrosis. Methods. 35 patients post-major knee surgery with arthrofibrosis and mean range of movement (ROM) of 68° were recruited. Both the STAK intervention and control group received standard physiotherapy for eight weeks, with the intervention group additionally using the STAK at home. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Oxford Knee Scores (OKS) were collected at all timepoints. An acceptability and home exercise questionnaire capturing adherence was recorded after each of the interventions. Results. Compared to the control group, the STAK intervention group made significant gains in mean ROM (30° versus 8°, p < 0.0005), WOMAC (19 points versus 3, p < 0.0005), and OKS (8 points versus 3, p < 0.0005). The improvements in the STAK group were maintained at long-term follow-up. No patients suffered any complications relating to the STAK, and 96% of patients found the STAK tool ‘perfectly acceptable’. Conclusion. The STAK tool is effective in increasing ROM and reducing pain and stiffness. Patients find it acceptable and adherence to treatment was high. This study indicates that the STAK tool would be of benefit in clinical practice and may offer a new, cost-effective treatment for arthrofibrosis. Cite this article: Bone Joint Open 2020;1-8:465–473

The painful hip without obvious clinical or radiographic signs of complications is a well-known scenario for surgeons. The clinical tools we have access to currently lack a dynamic test for detecting early signs of motion between implant and bone.

A new software, Sectra IMA, has a potential to facilitate diagnosis of early implant loosening by analysis of paired CT exams. In clinical practise the two scans are acquired by endpoint of a possible motion, “a provocation CT”, for example maximal external and internal rotation in a CT hip examination. 20 years of research by Olivecrona and Weidenhielm is the scientific background for the technique. Early results are presented by Sandberg et al 2022.

To further validate and create clinical evidence more extensive clinical studies is needed. A proposal for a multicentric, global clinical study will be presented for further discussion.

A new technique for diagnosis of acetabular cup loosening using computed tomography: preliminary experience in 10 patients. Henrik Olivecrona, Lotta Olivecrona, Lars Weidenhielm, Marilyn E Noz, Jocelyn Kardos, Gerald Q Maguire Jr, Michael P Zeleznik, Peter Aspelin. Acta Orthop. 2008 Jun;79(3):346-53. doi: 10.1080/17453670710015247.

Inducible displacement CT increases the diagnostic accuracy of aseptic loosening in primary total hip arthroplasty. Sandberg O, Carlsson S, Harbom E, Cappelen V, Tholén S, Olivecrona H, Wretenberg P. Acta Orthop. 2022 Oct 31;93:831-836. doi: 10.2340/17453674.2022.5240.PMID: 36314542

Aim: The aim of this investigation was to determine how the rotational axis of the wrist moves as the hand goes from full ulna to full radial deviation. Materials & Methods: Ulna to radial deviation was assessed in 30 normal wrists in 15 normal subjects aged 19 to 32. Movement was measured with a Polhemus Fastrak (TM) magnetic tracking system. The system has translational and rotational measurement accuracies of 1 mm and 1 degree respectively. Subjects placed their palms on a flat wooded stool and had movement sensors attached over their 3rd metacarpal and distal radius. These sensors then recorded movement as the hand moved from full ulna to full radial deviation. Results: The mean range of movement was 47 degrees (SD 8). In full ulna deviation the wrist rotational axis was in the region of the lunate/capitate. As the hand moved towards radial deviation, the axis moved distally. At the end of the movement the mean distal displacement was 22 mm (SD 14). In 17 wrists the distal displacement was accompanied by mean displacement towards the ulna of 13 mm (SD 8). In 13 wrists the distal displacement was accompanied by a mean displacement towards the radius of 7 mm (SD 5). Conclusion: The rotational axis position indicates how the wrist is moving during radial deviation. In early movement, when the axis is proximal, there is a high degree of sideways translation. In later movement, when the axis is distal, there is more rotational movement. In some cases the axis moved distally and toward the radius, whereas in other cases it moved distally and toward the ulna. This spectrum of movement may support the theory of 2 type of carpal movement. i.e. Column movers and row movers [Craigen & Stanley]

We present the first study in vivo of meniscal movement in normal knees under load. Using an open MR scanner, allowing imaging in physiological positions in near to real-time, 16 young footballers were scanned moving from full extension to 90° flexion in the sagittal and coronal planes. Excursion of the meniscal horns, radial displacement and meniscal height were measured. On weight-bearing, the anterior horn of the medial meniscus moves through a mean of 7.1 mm and the posterior horn through 3.9 mm, with 3.6 mm of mediolateral radial displacement. The height of the anterior horn increases by 2.6 mm and that of the posterior horn by 2.0 mm. The anterior horn of the lateral meniscus moves 9.5 mm and the posterior horn 5.6 mm, with 3.7 mm of radial displacement. The height of the anterior horn increases by 4.0 mm, and that of the posterior horn by 2.4 mm. In non-weight-bearing, the anterior horn of the medial meniscus moves 5.4 mm and the posterior horn 3.8 mm, with 3.3 mm of radial displacement. The anterior horn of the lateral meniscus moves 6.3 mm, and the posterior horn 4.0 mm, with 3.4 mm of radial displacement. The most significant differences between weight-bearing and non-weight-bearing were the movement and vertical height of the anterior horn of the lateral meniscus

A method of assessing foot movement suitable for use in clinical practice is presented. The method assesses the component of movement in the horizontal plane which is produced by rotating the calcaneum about the axis of the subtalar joint

Aim: The carpal bone arrangement can be described as a matrix of two rows and three columns. There a various theories as to how the bones within the matrix move during ulna to radial deviation. One theory suggests that there are two types of wrist movement, namely Row & Column. 1. . The aim of this study was to investigation how the rotational axis of the wrist moves as the hand goes from full ulna to full radial deviation. Materials and Methods: Ulna to radial deviation was assessed in 50 normal wrists in 25 normal subjects aged 19 to 57. Movement was measured with a Polhemus Fastrak (TM) magnetic tracking system. The system has translational and rotational measurement accuracies of 1 mm and 1 degree respectively. Subjects placed their palms on a flat wooded stool and had movement sensors attached over their 3rd metcarpal and distal radius. These sensors then recorded movement as the hand moved from full ulna to full radial deviation. Results: The mean range of movement was 45 degrees (SD 7). In full ulna deviation the wrist rotational axis was in the region of the lunate. As the hand moved towards radial deviation, the axis moved distally. At the end of the movement the mean distal displacement was 21 mm (SD 15). In 32 wrists the distal displacement was accompanied by mean displacement towards the ulna of 12 mm (SD 8). In 18 wrists the distal displacement was accompanied by a mean displacement towards the radius of 8 mm (SD 5). Conclusion: The rotational axis position indicates how the wrist is moving during radial deviation. In early movement, when the axis is proximal, there is a high degree of sideways translation. In later movement, when the axis is distal, there is more rotational movement. In some cases the axis moved distally and toward the radius, whereas in other cases it moved distally and toward the ulna. This spectrum of movement may support the theory of 2 types of carpal movement. i.e. Column movers and row movers. 1.

The most widely accepted method to measure kneekinematics is using external movement registration with the aid of skin-mounted markers. However, a large error component appears due to skin movement relative to the underlying bone. The goal of this study is to use fluoroscopy to quantify skin movement artefacts in patients with a total knee prosthesis during a step-up task. The most widely accepted method to measure knee kinematics is using external movement registration with the aid of skin-mounted markers. However, a large error component appears due to skin movement relative to the underlying bone. The goal of this study is to use fluoroscopy to quantify skin movement artefacts in patients with a total knee prosthesis during a step-up task. Translational and rotational errors attributed to soft tissue movement were three times larger for the femur than for the tibia about allaxes. The mean of the absolute rotational differences for the femur were2.6, 3.3 and 1.7 degrees about the X, Y and Z axes respectively. Absolute peak differences for individual subjects were 9.1, 12.9 and 10.5 mm along the X, Y and Z axes respectively. This is the first study examining the 3D relative motion between surface-mounted and bone-anchored markers without the use of cortical pins anchored to the tibia and/or the femur. The results revealed no regular pattern of soft tissue error between subjects indicating the unlikely success of numerical methods for modeling and removing soft tissue motion artifacts when using standard motion capture methods

Background. The clinical assessment of Chronic Low Back Pain (CLBP) is usually undertaken at a single time point at clinic rather than through continuous monitoring. To address this, a wearable prototype sensor to monitor motion of the lumbar spine and pelvis has been developed. Sensor Development, Testing and Results. The system devised was based on inertial sensor technology combined with wireless Body Sensor Network (BSN) platform. This was tested on 16 healthy volunteers for ten common movements (including sit to stand, lifting, walking, and stairs) with results validated by optical tracking. Preliminary findings suggest good agreement between the optical tracker and device with mean average orientation error (°) ranging from 0.1 ± 2.3 to 4.2 ± 2.6. The sensor repeatability errors range from 0 to 4° while subject movement variability ranged from 4% to 14%. Parameters of angular motion suggest greater movement of the lumbar spine compared to the pelvis with mean velocities (°/s) for lumbar spine ranging from 15.3 to 74.13 and pelvis ranging from 5.6 to 40.74. Further analysis revealed the extent to which the pelvis was engaged, as a proportion of the total movement. This demonstrated that the pelvis underwent smooth transitions from low (0.02), moderate (0.4) to high (0.99) use during different movement phases. Conclusion. A wearable sensor has been developed to record and quantify lumbar and pelvic movement. This permits an understanding of the lumbo-pelvic relationship to be characterized in an objective way during daily tasks. The next stage of the project will involve testing with CLBP patients

We used three-dimensional movement analysis by computer modelling of knee flexion from 0° to 50° in 14 knees in 12 patients with recurrent patellar dislocation and in 15 knees in ten normal control subjects to compare the in vivo three-dimensional movement of the patella. Flexion, tilt and spin of the patella were described in terms of rotation angles from 0°. The location of the patella and the tibial tubercle were evaluated using parameters expressed as percentage patellar shift and percentage tubercle shift. Patellar inclination to the femur was also measured and patellofemoral contact was qualitatively and quantitatively analysed. The patients had greater values of spin from 20° to 50°, while there were no statistically significant differences in flexion and tilt. The patients also had greater percentage patellar shift from 0° to 50°, percentage tubercle shift at 0° and 10° and patellar inclination from 0° to 50° with a smaller oval-shaped contact area from 20° to 50° moving downwards on the lateral facet. Patellar movement analysis using a three-dimensional computer model is useful to clearly demonstrate differences between patients with recurrent dislocation of the patella and normal control subjects

When performing the Scandinavian Total Ankle Replacement (STAR), the positioning of the talar component and the selection of mobile-bearing thickness are critical. A biomechanical experiment was undertaken to establish the effects of these variables on the range of movement (ROM) of the ankle. Six cadaver ankles containing a specially-modified STAR prosthesis were subjected to ROM determination, under weight-bearing conditions, while monitoring the strain in the peri-ankle ligaments. Each specimen was tested with the talar component positions in neutral, as well as 3 and 6 mm of anterior and posterior displacement. The sequence was repeated with an anatomical bearing thickness, as well as at 2 mm reduced and increased thicknesses. The movement limits were defined as 10% strain in any ligament, bearing lift-off from the talar component or limitations of the hardware. Both anterior talar component displacement and bearing thickness reduction caused a decrease in plantar flexion, which was associated with bearing lift-off. With increased bearing thickness, posterior displacement of the talar component decreased plantar flexion, whereas anterior displacement decreased dorsiflexion

The aim of this study was to investigate how the rotational axis of the wrist moves as the hand goes from full ulna to full radial deviation. Fifty normal wrists in 25 subjects were assessed with a Polhemus Fastrak (TM) magnetic tracking system. The subjects, aged 19 to 57, placed their palms on a flat wooded stool. Sensors were attached over their 3rd metcarpal and distal radius. The sensors then recorded movement from ulna to radial deviation. The translational and rotational measurement accuracies were 1 mm and 1 degree respectively. The mean range of movement was 45 degrees (SD 7). In ulna deviation the axis was in the region of the lunate. As the hand moved towards radial deviation, the axis moved distally. At the end of the movement the mean distal displacement was 21 mm (SD 15). In 32 wrists the distal displacement was accompanied by a mean displacement towards the ulna of 12 mm (SD 8). In 18 wrists the distal displacement was accompanied by a mean displacement towards the radius of 8 mm (SD 5). The rotational axis position indicates how the wrist is moving during radial deviation. In early movement, when the axis is proximal, there is a high degree of sideways translation. In later movement, when the axis is distal, there is more rotational movement. In some cases the axis moved distally and toward the radius, whereas in other cases it moved distally and toward the ulna. This spectrum of movement may support the theory of 2 types of carpal movement proposed by Craigen and Stanley (J. Hand Surg, 20B, 165–170, 1995)

Introduction. It is essential to investigate the tribological maturation of tissue-engineered cartilage that is to be used in medical applications. The frictional performances of tissue engineered cartilage have been measured using flat counter surfaces such as stainless steel, glass or ceramics. However, the measured friction performances were significantly inferior to those of natural cartilage, likely because of cartilage adhesion to the counter surface. Tamura et al. reported that a poly (2- methacryloyloxyethyl phosphoryl-choline (MPC)) grafted surface shows low friction coefficient against cartilage without the adhesion to be equivalent to those for natural cartilage-on-cartilage friction. [1]. On the other hand, Yamamoto et al. reported that applying a relative sliding movement had a potential to alter the expression of tribological function of regenerated cartilage of chondrocytes. [2] In this paper, the effects of the relative sliding movement on the expression of bone marrow stromal cells (BMSC)s were investigated using the poly(MPC) grafted surface as a counter surface. Material and methods. BMSCs seeded onto fibroin sponge scaffolds were cultured by using the stirring chamber system (Figure 1), which can apply a relative tribological movement to the surface of the specimens. Three culture conditions were applied (dynamic in stirring chamber as frequency as 40 min [D1], as 40 sec [D2] and static in stirring chamber group [S]). The specimens were set into stirrer on a poly(MPC) grafted surface (MPC polymer coated surface, SANSYO). As a counter surface in friction tests, the poly(MPC) grafted surface was prepared by atom transfer radical polymerization, and the regenerated cartilage was prepared by seeding 5×10. 5. cells (BMSCs from rat bone marrow) onto fibroin sponge scaffolds (8 mm diameter and 1 mm thickness) and by 14 days culture. Results and Discussion. The friction coefficient in D1 group tended to be lower than that in S group. Similarly, D2 group tended to show lower value than S group (Figure 2). However, the value of D1 and D2 group was extraordinary high, compared to that of intact articular cartilage. The GAG amount of D1 and D2 group was significantly higher than that of S group. All of the groups showed Collagen type I and type II staining at the surface. S group showed wider staining region than D1 and D2 group. However there was no Alcian Blue staining (Figure 3). These results indicate that the stirring chamber system tended to improve the frictional performance of regenerated tissue. However this relative tribological movement has not a potential to induce effects on the differentiation of BMSCs to chondrocytes

After a unicompartmental Oxford knee replacement, a clear lateral radiographic view of the components may be obtained without the shadow of prosthetic components in the other compartment. Radiographs of 20 knees were studied; with the patient supine and the muscles relaxed, views with the knee at full extension and 90 degrees of flexion were obtained and the movement of the meniscal bearings over this range of flexion was measured. The bearings were found to move backwards on the tibia through an average distance of 4.4 mm (range 0.0 to 13.5 mm) in the medial compartment and 6.0 mm (range 1.6 to 13.0 mm) in the lateral compartment. These movements were in the same direction as that observed in cadaver specimens but smaller in magnitude. At 90 degrees of flexion, radiographs were obtained with the tibia twisted manually to the limits of medial and lateral rotation. The average movement of the bearings between these extremes was found to be 6.6 mm in the medial compartment and 5.1 mm in the lateral; their movements on the tibia were in opposite directions in the two compartments. Bearing movement was still present in knees examined five years after operation

Introduction: Activities that require extreme hip movement can dislocate hip implants in the early post operative phase. The aim of this study was to assess the movement of the hip using four different techniques to retrieve an object from the floor. Methods: An electromagnetic tracker was used to measure hip movement during these retrieval techniques:-. Flexing forward to pick up an object between the feet. Standing to the side of the object and bending. Squatting to pick up an object between the feet. Kneeling on one knee to pick up. Measurements were taken from 50 hips in 25 normal subjects aged 21 to 61. Sensors were attached over the iliac crest and the mid-shaft of the lateral thigh. Data was collected as each technique was repeated 3 times. The tracker recorded hip flexion and rotation data at 10 hertz, with an accuracy of 0.15 degree. Results: For each of the four techniques the respective mean (SD) movements were:-. Flexion: 75.8(28.6), 79.2(27.2), 87.5(29.7) and 30.4(17.3). Extension: −0.2(2.5), 0.5(1.9), 0.1(2.3) and −0.4(3.3). Internal rotation: 2.9(5.2), 1.4(3.4), 10.1(9.9) and 8.5(6.9). External rotation: 12.6(10.3), 20.1(12.1), 11.9(6.5) and 7.3(7.1). Kneeling had significantly less flexion and external rotation than all the other techniques (paired t-test, P< < 0.001). Discussion: Flexion and external rotation were the most significant movements for each technique. The movements with the least and most flexion were kneeling (30.40) and squatting (87.50). The movement with the least and most external rotation were kneeling (7.30) and side pick up (20.10). Kneeling has the least amount of movement, therefore, it minimises the risk of dislocation when retrieving an object from the floor

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. 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 150degree. 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. 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. The lateral femoral condyle may sublux from the tibia during kneeling inpatients who had full flexion after TKA. These findings should call for changes in the implant design to accommodate the lateral condyle roll back

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 150degree). 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 have full flexion after TKA. These findings should call for changes in the implant design to accommodate the lateral condyle roll back

Modular knee bearings typically consist of a femoral component, a tibial base-plate and a polyethylene insert, which is located in the tibial base-plate using some sort of locking mechanism. Although modular knee bearings offer many advantages there is the potential for micro-motion between the tibial insert and the base-plate. Tests were performed on six large Kinemax Plus knee bearings (snap-fit design) to evaluate the amount of movement between the tibial inserts and the tibial base-plates. The knee bearings were tested up to one million cycles on the Durham Six-Station Knee Wear Simulator which subjected the bearings to similar motion and loading profiles that would be experienced by the natural knee during walking. The movement of the tibial inserts was measured with dial gauges (accuracy of ±0.01 mm) before and after the bearings were tested on the simulator, when unloaded, and throughout the tests whilst the bearings were being dynamically loaded in the simulator. Movement occurred between the tibial insert and the tibial base-plate after initial assembly due to the snap-fit mechanism used to locate the tibial insert within the tibial base-plate. However, this decreased appreciably when the bearings were loaded in the simulator. The amount of movement did not change with time when the bearings were continuously loaded in the simulator. However, after each test the amount of movement of the tibial inserts, when unloaded, was less than before the test. This was thought to be due to creep of the UHMWPE inserts. The movement between the tibial insert and tibial base-plate in-situ is likely to be much less than that observed by a surgeon at the time of assembly due to loading of the knee bearing in the body. However, the amount of movement when the tibial inserts are loaded may still be great enough to produce a second interface where wear of the tibial insert may take place

Background: The determinants of range of movement following knee replacement may be surgically modifiable (tibial slope, posterior condylar offset or the level of the joint line) or non modifiable (pre-operative range of movement, sex or BMI). We aimed to quantify the influence of these factors upon restoration of flexion in the arthritic knee following knee replacement. Methods: Patients were included from two prospective trials for three different designs of knee replacement. Range of movement was recorded using a standard measuring technique preoperatively and 12 months after surgery. Radiological measurement was done by an independent observer and included the preoperative posterior condylar offset and the postoperative tibial slope, posterior condylar offset, posterior condylar offset ratio, varus-valgus alignment and Insall ratio. Multivariate analysis using stepwise selection was performed to determine the significant predictors of the range of movement at 12 months. Results: The study includes 133 knee replacements performed on 125 patients. Complete clinical and radiographic data for preoperative and 12-month assessment was available for 101 knees and only these were included for the analyses. There was no significant difference between the three groups in terms of postoperative range of movement or the radiological parameters measured. Multivariate analysis after adjusting for age, sex, diagnosis and the type of prosthesis revealed that the only significant correlates of range of movement at 12-months were the difference in posterior condylar offset ratio, tibial slope and preoperative range of movement. Moderate correlation was noted between range of movement at 12 months and posterior tibial slope (R=0.58) and the difference of post femoral condylar offset (that is, post-operative minus preoperative posterior condylar offset, R=0.65). Preoperative range of movement had only a weak correlation with post-operative range of movement (R=0.20). Conclusions: We found that the posterior femoral condylar offset had the greatest impact upon final range of movement. We would encourage the operating surgeon at pre-operative templating to take this into account when choosing size and design of femoral component

The pathogenesis of aseptic loosening of total joint prostheses is not clearly understood. Two features are associated with loosened prostheses, namely, particulate debris and movement of the implant. While numerous studies have evaluated the cellular response to particulate biomaterials, few have investigated the influence of movement of the implant on the biological response to particles. Our aim was therefore to test the hypothesis that excessive mechanical stimulation of the periprosthetic tissues induces an inflammatory response and that the addition of particulate biomaterials intensifies this. We allocated 66 adult Beagle dogs to four groups as follows: stable implants with (I) and without (II) particulate polymethylmethacrylate (PMMA) and moving implants with (III) and without (IV) particulate PMMA. They were then evaluated at 2, 4, 6, 12 and 24 weeks. The stable implants were well tolerated and a thin, fibrous membrane of connective tissue was observed. There was evidence of positive staining in some cells for interleukin-6 (IL-6). Addition of particulate PMMA around the stable implants resulted in an increase in the fibroblastic response and positive staining for IL-6 and tumour necrosis factor-alpha (TNF-α). By contrast, movement of the implant resulted in an immediate inflammatory response characterised by large numbers of histiocytes and cytokine staining for IL-1ß, TNF-α and IL-6. Introduction of particulate PMMA aggravated this response. Animals with particulate PMMA and movement of the implant have an intense inflammatory response associated with accelerated bone loss. Our results indicate that the initiation of the inflammatory response to biomaterial particles was much slower than that to gross mechanical instability. Furthermore, when there was both particulate debris and movement, there was an amplification of the adverse tissue response as evidenced by the presence of osteolysis and increases in the presence of inflammatory cells and their associated cytokines

I have tried to stimulate interest in movement as a method of treatment. It is too much to expect that I shall have won over to my way of thinking doctors who are addicts of rest. I shall be content if they will occasionally ask: "Is my splint really necessary?"

Introduction. Hip-Spine syndrome has various clinical aspects. For example, schoolchild with severe congenital dislocation of the hip have unfavorable standing posture and disadvantageous motions in ADL. Hip-Spine syndrome is closely related closely as the adjacent lumbar vertebrae and the hip joint. Furthermore, not only the pelvis and the lumbar spine, but also the neck position might influence on the maximum hip flexion angle. In this study, we examined the maximum hip flexion angle and pelvic movement angle by observing the lumbar spine, the pelvis and the neck in three different positions. Subjects and Methods. The participants were five healthy volunteers (three males and two females) and ranged in age from 16 to 49 years. We measured the hip flexion angle (=∠X) and the pelvic tilt angle (=∠Y), using Zebris WinData and putting the six markers on skin. The positions of the marker are Femur lateral condyle (M1), Greater trochanter (M2), Lateral margin of 10th rib (M3), Anterior superior iliac spine (M4), Superior lateral margin of Iliac (M5), and Acromion (M6). We performed maximum hip flexion three times in three positions and measured ∠X (=∠M1,2,3) and ∠Y (=∠M4,5,6) and calculated the mean and SD of each position. The first position (P1) that we investigated is the regular position specified by the Japanese Orthopedics Association and Rehabilitation Medical Association. The second position (P2) is performed in the limited position of the posterior pelvic tilt and lumbar movement, by placing the tube under the subject's lower back. The third position (P3) is the altered limited position of P2 added by placing the 500ml PET bottle filled water under the back of the subject's neck. Analysis. A two way factorial analysis of variance was used for statistical analysis to examine the difference among three different positions (P1, P2 and P3) in ∠X and ∠Y. A significance level was set at P < 0.05. We also calculated Spearman rank correlation coefficients to determine the correlation between ∠X and ∠Y. Results. There was a statistically significant difference among three different positions (P1, P2 and P3) in both ∠X and ∠Y (p < 0.01). Slight strong correlations were found between ∠X and ∠Y in three different positions. (r =0.5178571). The smallest values of ∠X and ∠Y were obtained in P1. The values of ∠X and ∠Y in P3 were all smaller than those in P2. Conclusions. The limited movement of pelvic and lumbar spine, and neck different positions give the limit to a maximum hip joint flexion angle

The aim of this study was to define objectively gait function in children with treated congenital talipes equinovarus (CTEV) and a good clinical result. The study also attempted an analysis of movement within the foot during gait. We compared 20 children with treated CTEV with 15 control subjects. Clinical assessment demonstrated good results from treatment. Three-dimensional gait analysis provided kinematic and kinetic data describing movement and moments at the joints of the lower limb during gait. A new method was used to study movement within the foot during gait. The data on gait showed significantly increased internal rotation of the foot during walking which was partially compensated for by external rotation at the hip. A mild foot drop and reduced plantar flexor power were also observed. Dorsiflexion at the midfoot was significantly increased, which probably compensated for reduced mobility at the hindfoot. Patients treated for CTEV with a good clinical result should be expected to have nearly normal gait and dynamic foot movement, but there may be residual intoeing, mild foot drop, loss of plantar flexor power with compensatory increased midfoot dorsiflexion and external hip rotation

1. The range of variation in the movements at the metatarso-phalangeal and interphalangeal joints of the big toe in fifty males has been investigated by means of lateral radiographs. 2. In the "neutral" position the proximal phalanx is dorsiflexed on the metatarsal and the distal phalanx dorsiflexed on the proximal. Sometimes the distal phalanx is plantar flexed on the proximal but this is not associated with any obvious abnormality of function. 3. There is a wide variation between individuals in the amount of movement found at these joints. 4. At the metatarso-phalangeal joint dorsiflexion is much more free than plantar flexion. The opposite is the case at the interphalangeal joint. 5. There is no significant difference between the right and left sides. Only in plantar flexion at both joints are there significant reductions in the range of movement in older age groups. These reductions are not functionally important. 6. There is an inverse relationship between active and passive dorsiflexion: the greater the range of active dorsiflexion, the less is the range of additional passive dorsiflexion. 7. In lateral radiographs the head of the metatarsal is always rounded

Introduction: Total lumbar disc replacement (TLDR) is a motion-preserving alternative to lumbar spinal fusion for degenerative disc disease. Although in vitro cadaveric studies have provided invaluable information in preserving motion and possibly prevent abnormal loading at the adjacent level for TLDR, there is still lack evidence of in vivo consequences for sagittal balance and movement. Purpose: Aim of our prospective non-randomized clinical study was to analyze the consequences for segmental and sagittal balance and movement of TLDR. Materials and Methods: From October 2001 trough December 2006, 1-year minimum follow-up, 78 TLDR were implanted in 57 patients. 31 (54.4%) were female, 26 (45.6%) male. Mean age at surgery was 41.77±7.46 ys (30–57). 36 (63.2%) had single level TLDR, 15 (26.4%) 2-level, 3 (5.2%) 3-level, and 3 (5.2%) hybrid constructs. Replaced discs were L3–L4 in 5 (6.4%) cases, L4–L5 in 32 (41%), and L5-S1 in 41 (52.6%). AP, lateral, and flexion-extension periodical lumbar X-rays allowed to measure segmental lordosis, lumbar lordosis, segmental motion, and lumbar motion pre-, post-op, and at follow-ups. Analyses were performed using 9.2 STATA statistical software, and 12.0 SPSS version. Differences were assessed using t or Mann-Whitney tests. Samples of 3-level and hybrid constructs were too small for comparative analysis. Results: Mean follow-up was 35.02±17.58 ms. Lumbar lordosis passed from 43.87°±11.82° pre-op to 46.42°±10.83° post-op (P=0.062379), and 47.98°±11.97° at last follow-up (P=0.008544). L3–L4 segmental lordosis passed from 6.90°±3.51° pre-op to 10.85°±5.22° post-op (P=0.026971), and 11.80°±2.59° at last f-u (P=0.064873). L4–L5 segmental lordosis passed from 9.86°±5.06° pre-op to 13.83°±6.21° post-op (P=0.000611), and 13.21°±6.11° at last f-u (P=0.000631). L5-S1 segmental lordosis passed from 17.02°±5.32° pre-op to 22.46°±6.27° post-op (P=0.000001), and 23.03±6.81° at last follow-up (P= P=0.000000). Concerning movement, there was no differences between pre- and post-op L3–L4 (P=0.656045), L4–L5 (P=0.458793), or L5-S1 (P=0.157879) ROM. Even lumbar motion had no difference between pre- and post-op. There was no differences between single and double level replacement about lumbar and segmental lordosis, and about lumbar and segmental ROM. Conclusion: In vivo implanted TLDR affected sagittal balance, increasing segmental and lumbar lordosis. TLDR avoid spinal fusion maintaining normal motion, both segmental and lumbar. Single and double level disc arthroplasty have similar effects

Abstract

We investigated the effect of neck dimension upon cervical range of movement. Data relating to 100 subjects healthy subjects aged between 20 and 40yrs was recorded with respect to age, gender and ranges of movement in three planes. Additionally two commonly used methods of measuring neck motion, chin-sternal distance and uniplanar goniometer, were assessed against a validated measurement tool the CROM goniometer (Performance Attainment Associates, Roseville, MN). Using multiple linear regression analysis it was determined that sagittal flexion (P= 0.0021) and lateral rotation (P< 0.0001) were most closely related to neck circumference alone whereas lateral flexion (P< 0.0001) was most closely related to a ratio of circumference and length. The uniplanar goniometer has some usefulness when assessing neck motion, comparing favourably to chin-sternal distance that has almost no role. Neck dimension should be incorporated into cervical functional assessment. One should be wary about recorded values for neck motion from non-validated measurement tools

Cervical orthoses are currently used in the pre-hospital stabilization of trauma patients and also as part of the definitive non-operative treatment of injuries of the cervical spine. The construct stability of orthoses is compromised by virtue of the fact that the cervical spine exhibits the greatest range of movement amongst the spinal segments and also because of the complex composite nature of neck movements. To date, data has been difficult to attain comparing the various orthoses, in the various planes of movement of the cervical spine. Various methods including the use of inclinometers, goniometers, radiography, computerized tomography and cineroentgenography have been used in an attempt to measure these movements but none have provided satisfactory triplanar data. This paper uses the Zebris ultrasonic 3-D motion analysis system to measure flexion, extension, range of lateral bending and range of axial rotation in five similar male and five similar female subjects with no history of neck injuries. The subjects were tested in a soft and hard collar, Philadelphia, Miami J and Minerva. Results show that the Minerva is significantly the most stable construct for restriction of movement in all planes in both groups (p< 0.002 vs. all groups, Student’s t-test), but more impressively in the female group. In the male group, the standard hard collar performs second best in flexion, lateral bending and axial rotation. In the female group, the second most stable orthosis is the Philadelphia in flexion/extension and the hard collar in lateral bending and axial rotation (p< 0.05 vs. next most stable in all cases, Student’s t-test). The soft collar in both groups offered only minimal resistance to movement in any plane, e. g. 45.07° vs. 46.45° extension vs. normal in males and 40.15° vs. 41.8° extension vs. normal in females. Looking at these results together allows the ranking of the measured orthoses in order of the three-dimensional stability they offer. Furthermore, they validate the Zebris as a reliable and safe method of measurement of the complex movements of the cervical spine with low intersubject variability. In conclusion, this paper, for the first time presents reproducible data incorporating the composite triplanar movements of the cervical spine thus allowing comparative analysis of the three-dimensional construct stability of the studied orthoses

Aim: One of the issues of metatarsophalangeal joint (MTPJ) replacements is that they do not restore full range of movement (RO M). However, full RO M is not needed for functional walking. The aim of this study was to measure the difference between the functional and maximum ROM of the first metatarsophalangeal joint. Materials & Method: The functional and maximum ROM of 32 MTPJs in 16 normal adults were measured with a video imaging system. The system first measured the ROM as the subject walked past the camera. It then measured the ROM as standing maximum extension tests were performed. Results: During functional walking tests the mean ROM was 37.9 degrees (SD 12.2). During maximum standing extension tests the mean ROM was 64.9 degrees (SD 11.3). Therefore the functional walking ROM was only 58% of the maximum standing extension ROM, with a mean difference of 27 degrees. A paired t-test comparison showed P< 0.0001. Discussion: MTPJ arthroplasty has previously been criticised because it does not restore full RO M. However, the results of this study suggest that the functional movements required in normal gait are significantly less than what can be maximally achieved in clinical standing extension tests. Therefore arthroplasty can be a suitable treatment if it can provide an adequate functional RO M. Conclusion: The results of this study show that the functional range of movement required for walking is only 58% of the maximum extension ROM of the first MTP joint. Therefore, MTP joint replacements do not need to restore maximum extension, as normal gait can be achieved without this

Treatment by continuous passive movement at home is an alternative to immobilisation in a cast after surgery for club foot. Compliance with the recommended treatment, of at least four hours daily, is unknown. The duration of treatment was measured in 24 of 27 consecutive children with a mean age of 24 months (5 to 75) following posteromedial release for idiopathic club foot. Only 21% (5) of the children used the continuous passive movement machine as recommended. The mean duration of treatment at home each day was 126 minutes (11 to 496). The mean range of movement for plantar flexion improved from 15.2° (10.0° to 20.6°) to 18.7° (10.0° to 33.0°) and for dorsiflexion from 12.3° (7.4° to 19.4°) to 18.9° (10.0° to 24.1°) (both, p = 0.0001) when the first third of therapy was compared with the last third. A low level of patient compliance must be considered when the outcome after treatment at home is interpreted

Introduction: Hip replacement patients are prone to dislocations during extreme hip movement in the early post operative period. An activity of daily living that puts them at risk of dislocation is picking an object off the floor. The aim of this study was to assess the movement of the hip using different techniques to pick an object of the floor. Methods: An electromagnetic tracking system was used to assess hip movements for four different techniques in picking an object from the floor. These were -. Flexing forward to pick an object up between the feet. Standing to the side of the object and bending to pick it up. Squatting to pick an object up between the feet. 4. Kneeling on one knee to pick up. Measurements were taken from 40 hips in 20 normal subjects aged 21 to 61. Sensors were attached over the iliac crest and the mid-shaft of the lateral thigh. Data was then collected from the magnetic tracker as each technique was repeated 3 times. The system recorded hip flexion and rotation data at 10 hertz, with an accuracy better than 1 degree. Data was then analysed and the mean readings for each technique were compared. Results: For each of the four techniques listed above the respective mean (SD) results were:. Flexion: 81.4 (27.5), 83.3 (27.6), 93.3 (28.7) and 33.5 (17.6) degrees. Extension: −0.2 (2.0), −0.3 (1.8), −0.1 (2.5) and 0.4 (3.2) degrees. Internal rotation: 3.4 (5.9), 1.6 (3.8), 10.1 (10.4) and 9.5 (7.1) degrees. External rotation: 13.0 (8.6), 22.7 (13.8), 13.2 (6.9) and 7.5 (7.0) degrees. The most significant movements for each technique were flexion and external rotation. The movements with the least and most flexion were kneeling (33.5 deg) and squatting (93.3 deg). They were significantly different with a paired t-test p< < 0.001. The movement with the least and most external rotation were kneeling (7.5 deg) and side pick up (22.7 deg). They were significantly different with a paired t-test, p< < 0.001. Conclusion: This study has found that the most effective technique to pick up an object from the floor is kneeling as this has the least amount of flexion and external rotation. We conclude that this is the safest technique in carrying out this activity in the early post operative stage for patients who have undergone a total hip replacement

We report a prospective study, using multivariate analysis, of the factors which influence the range of movement after total knee arthroplasty in 74 patients with 83 arthroplasties at a mean follow-up of 23.6 months (12 to 41). All the patients had a diagnosis of osteoarthritis, a severely disabled knee with a Knee Society system score of less than 60, varus deformity, no previous surgery to the knee, identical prostheses implanted with a similar surgical technique, and no postoperative complications which may have affected the range of movement. The most important factors which influenced the range of movement after arthroplasty were the preoperative range of flexion and the body-weight of the patient. There was a significant improvement in flexion and reduction of flexion contracture at each successive review up to 12 months after operation. Patients with restricted movement before operation showed a satisfactory gain at final review

Objective. To compare the effectiveness of the Aspen, Aspen Vista, Philadelphia, Miami-J and Miami-J Advanced collars at restricting cervical spine movement in the sagittal, coronal and axial planes. Methods. Nineteen healthy volunteers (12 female, 7 male) were recruited to the study. Collars were fitted by an approved physiotherapist. Eight ProReflex (Qualisys, Sweden) infra-red cameras were used to track the movement of retro reflective marker clusters placed in predetermined positions on the head and trunk. 3D kinematic data was collected during forward flexion, extension, lateral bending and axial rotation from uncollared and collared subjects. The physiological range of motion in the three planes was analysed using the Qualisys Track Manager system. Results. The Aspen and Philadelphia collars were found to be significantly more effective at restricting movement in the sagittal plane compared to the Vista (p<0.001), Miami-J (p<0.001 and p<0.01) and Miami-J Advanced (p<0.01 and p<0.05) collars. The Aspen collar was significantly more effective at restricting axial rotation than the Vista (p<0.001) and the Miami-J (p<0.05) collars. The Aspen, Philadelphia, Miami-J and Miami-J Advanced collars were comparable at restricting lateral bending but the Vista was significantly less effective than all the collars at restricting movement in this plane. Conclusion. The Aspen collar was found to be superior to the other collars when measuring restriction of movement of the cervical spine in all planes, particularly the sagittal and transverse planes, while the Aspen Vista was the least effective collar

We used electrogoniometers to measure the range of movement (ROM) of the knee during various activities, comparing 50 patients with osteoarthritis of the knee (OA) with 20 healthy age- and sex-matched subjects. The minimum and maximum joint angles and the ranges of excursion of the patient and control groups were tested for significant differences, using an unrelated Student’s t-test with pooled variance. Knee flexion in patients with OA was significantly reduced during all activities (p < 0.05), but differences in knee extension were not significant except when patients negotiated stairs. We believe that this reduction in ROM is caused by inhibition due to pain when load-bearing. Static non-load-bearing measurements of the ROM poorly reflected the functional ROM, with a coefficient of determination (r. 2. ) of 0.59 in the patient group and 0.60 in the control group. Electrogoniometry of the ROM of the knee provides a reliable, accurate and objective measurement of knee function

We have attempted to quantify the influence of clinical, radiological and prosthetic design factors upon flexion following knee replacement. Our study examined the outcome following 101 knee replacements performed in two prospective randomized trials using similar cruciate retaining implants. Multivariate analyses, after adjusting for age, sex, diagnosis and the type of prosthesis revealed that the only significant correlates for range of movement at 12-months were the difference in posterior condylar offset ratio (p< 0.001), tibial slope (p< 0.001) and preoperative range of movement (p=0.025). We found a moderate correlation between 12-month range of movement and posterior tibial slope (R=0.58) and the difference of post femoral condylar offset (that is, post-operative minus preoperative posterior condylar offset, R=0.65). Posterior condylar offset had the greatest impact upon final range of movement highlighting this as an important consideration for the operating surgeon at pre-operative templating when choosing both the design and size of the femoral component

We performed a randomised, prospective study of 80 mobile-bearing total knee arthroplasties (80 knees) in order to measure the effects of varus-valgus laxity and balance on the range of movement (ROM) one year after operation. Forty knees had a posterior-cruciate-ligament (PCL)-retaining prosthesis and the other 40 a PCL-sacrificing prosthesis. In the balanced group (69 knees) in which the difference between varus and valgus was less than 2°, the mean ROM improved significantly from 107.6° to 117.7° (p < 0.0001). By contrast, in the 11 knees which were unbalanced and in which the difference between varus and valgus laxity exceeded 2°, the ROM decreased from a mean of 121.0° to 112.7° (p = 0.0061). We conclude that coronal laxity, especially balanced laxity, is important for achieving an improved ROM in mobile-bearing total knee arthroplasty

The purpose of this study was to establish if the Bateman prosthesis functions as a bipolar device moving primarily at the inner metal-on-polyethylene bearing as originally proposed, or as a unipolar hemiarthroplasty moving at the outer metal-on-cartilage surface as has recently been suggested. One hundred hips were examined at one year follow-up; 78 were examined again at two to four years. The replacement was performed for arthritis in 76 hips and for femoral neck fracture in 24. Movement was assessed both with and without weight-bearing. In 80% of the arthritis group the prosthesis functioned as a bipolar hip replacement with movement occurring primarily at the inner metal-on-polyethylene surface. By contrast, in 75% of the fracture group the prosthesis functioned largely as a unipolar device with movement occurring primarily at the outer metal-on-cartilage surface. In all cases examined serially the movement pattern was the same at two to four years as it has been at one year. Clearly, the action of the prosthesis depends on the condition of the acetabular cartilage

INTRODUCTION: The techniques to stabilize the patella can be divided into two groups: the first group seeks to change the direction of the extensor mechanism in order to medialize the extending force vector of the quadriceps muscle, e.g. by a distal medialization of the tibial tuberosity or a proximal realignment; the second seeks to reconstruct the medial patellofemoral ligament (MPFL). The goal of this study was therefore to measure changes in patellofemoral kinematics in the intact, MPFL deficient knee, after medial transfer of the tibial tuberosity, after proximal realignment as well as after reconstruction of the MPFL. METHODS: Eight fresh frozen right knee specimens were mounted in a knee simulator in which isokinetic flexion-extension motions were simulated. Extension cycles were simulated from 120° flexion to full knee extension with an extension moment of 31 Nm. Movement of the patella relative to the femur was measured using an ultrasound based 3D motion analysis system (Zebris, Isny, Germany). During the first test cycles, patellar movement under intact knee conditions were measured, while a constant 100 N laterally oriented force was applied by means of a steel cable attached to the patella. Subsequently, patellar movement was again measured after: transecting the MPL (deficient knee), performing a medialization of the tibial tuberosity, after reconstruction of the transected MPL using a semitendinosus autograft and after proximal realignment. RESULTS: The patella of the intact knee moved along a medial path with a maximum attained position of 8.8 mm at 25° of knee flexion. The patella of the deficient knee moved up to 4.6 mm (p=0.04) in the medial direction at maximal extension at 30° of knee flexion. After medial transfer of the tibial tuberosity patellar movement reached a maximum medial position of 12.8 mm (p=0.04) at 22° of knee flexion with the laterally oriented force. With a reconstructed MPL, the patella attained a maximum medial position 14.8 mm (p=0.04) at 24.0° of knee flexion. Following proximal realignment, the patella moved on a medial, but significant (p=0.03) different path up to 13.8 mm medially at 30° of knee flexion. In addition, following medialization of the tibial tuberosity and proximal realignment, the center of the patella was significantly (p=0.03) more internally rotated (tilted) than the physiologic patella. DISCUSSION: The shape of the movement curves after the stabilizating procedures resulted in a medialization relative to intact and deficient conditions. With the reconstructed medial patellofemoral ligament, the patella moved along the most medially oriented path with physiologic tilting. The results suggest that a semi-tendinous autograft can provide sufficient stabilization to prevent lateral displacement or subluxation with physiologic patellar tilt

The amount of anteroposterior laxity required for a good range of movement and knee function in a cruciate-retaining total knee replacement (TKR) continues to be debated. We undertook a retrospective study to evaluate the effects of anteroposterior laxity on the range of movement and knee function in 55 patients following the e-motion cruciate-retaining TKR with a minimum follow-up of two years. The knees were divided into stable (anteroposterior translation, ≤ 10 mm, 38 patients) and unstable (anteroposterior translation, > 10 mm, 17) groups based on the anteroposterior laxity, measured using stress radiographs. We compared the Hospital for Special Surgery (HSS) scores, the Western Ontario MacMasters University Osteoarthritis (WOMAC) index, weight-bearing flexion, non-weight-bearing flexion and the reduction of flexion under weight-bearing versus non-weight-bearing conditions, which we referred to as delta flexion, between the two groups at the final follow-up. There were no differences between the stable and unstable groups with regard to the mean HHS and WOMAC total scores, as well as weight-bearing and non-weight-bearing flexion (p = 0.277, p = 0.082, p = 0.095 and p = 0.646, respectively). However, the stable group had a better WOMAC function score and less delta flexion than the unstable group (p = 0.011 and p = 0.005, respectively). Our results suggest that stable knees with laxity ≤ 10 mm have a good functional outcome and less reduction of flexion under weight-bearing conditions than unstable knees with laxity > 10 mm following an e-motion cruciate-retaining TKR

To confirm whether developmental dysplasia of the hip has a risk of hip impingement, we analysed maximum ranges of movement to the point of bony impingement, and impingement location using three-dimensional (3D) surface models of the pelvis and femur in combination with 3D morphology of the hip joint using computer-assisted methods. Results of computed tomography were examined for 52 hip joints with DDH and 73 normal healthy hip joints. DDH shows larger maximum extension (p = 0.001) and internal rotation at 90° flexion (p < 0.001). Similar maximum flexion (p = 0.835) and external rotation (p = 0.713) were observed between groups, while high rates of extra-articular impingement were noticed in these directions in DDH (p < 0.001). Smaller cranial acetabular anteversion (p = 0.048), centre-edge angles (p < 0.001), a circumferentially shallower acetabulum, larger femoral neck anteversion (p < 0.001), and larger alpha angle were identified in DDH. Risk of anterior impingement in retroverted DDH hips is similar to that in retroverted normal hips in excessive adduction but minimal in less adduction. These findings might be borne in mind when considering the possibility of extra-articular posterior impingement in DDH being a source of pain, particularly for patients with a highly anteverted femoral neck. Cite this article: Bone Joint J 2014;96-B:580–9

We have previously shown that joint distraction and movement with a hinged external fixation device for 12 weeks was useful for repairing a large articular cartilage defect in a rabbit model. We have now investigated the results after six months and one year. The device was applied to 16 rabbits who underwent resection of the articular cartilage and subchondral bone from the entire tibial plateau. In group A (nine rabbits) the device was applied for six months. In group B (seven rabbits) it was in place for six months, after which it was removed and the animals were allowed to move freely for an additional six months. The cartilage remained sound in all rabbits. The areas of type II collagen-positive staining and repaired soft tissue were larger in group B than in group A. These findings provide evidence of long-term persistence of repaired cartilage with this technique and that weight-bearing has a positive effect on the quality of the cartilage

Introduction: The aim of this study was to compare hip movement between normal subjects and patients with a large Metal on Metal hip replacement, undertaking the task of retrieving an object from the floor. Methods: An electromagnetic tracker was used to measure movement as subjects retrieved an object with flexed hips and straight knees. Measurements were taken from a control group of 10 subjects with bilaterally normal hips, and 10 subjects with unilateral hip replacement. Sensors were attached over the iliac crest and the mid-shaft of the lateral thigh. Data was collected as each subject repeated the movement 3 times. The tracker recorded data at 10 hertz, with an accuracy of 0.15 degree. Results: For the normal group the mean hip flexion was 90.8 degrees (SD 20.1). For the arthroplasty group the mean flexion on the normal and operated sides were 74.0 (SD 21) and 72.7 degrees (SD 21) respectively. This was not significant (P= 0.83). However there was a significant difference in hip movement between the operated hips and those in the normal control group (P= 0.03). For the bilaterally normal group the mean hip rotation was 2.9 degrees internal (SD 11.8). For the arthroplasty group the mean rotation on the normal and operated sides were 9.4 degrees external (SD 9.5) and 6.9 degrees internal (SD 13.9) respectively. In this group there was a significant difference between the normal and operated side (P= 0.02). Discussion: This study has shown that patients with a unilateral hip replacement have no significant flexion difference between hips, when retrieving an object from the floor. However there was a significant difference compared to a control group with normal hips. A significant difference was also observed when comparing the rotation of an operated hip joint to the contra-lateral normal hip in the same individual

We studied active flexion from 90° to 133° and passive flexion to 162° using MRI in 20 unloaded knees in Japanese subjects. Flexion over this arc is accompanied by backward movement of the medial femoral condyle of 4.0 mm and by backward movement laterally of 15 mm, i.e., by internal rotation of the tibia. At 162° the lateral femoral condyle lies posterior to the tibia

Purpose: Femoral roll causes the sagittal plane axis of the knee to move posteriorly and anteriorly with flexion and extension. The aim of this study was to measure this movement with a surface marker imaging system and assess the effect of Anterior Cruciate Ligament (ACL) deficiency on the Sagittal Axis Pathway (SAP) of the knee. Method: Twelve normal and fourteen unilateral ACL deficient subjects were video recorded as they flexed and extended their knees in the sagittal plane. Video stills were captured at 150 intervals from 90o flexion to full extension. An imaging system was then used to extract the co-ordinates of leg markers from each still. These co-ordinates were then processed to derive the SAP for each knee throughout its range of movement. Results: Pooling all the normal results together (24 bilateral + 14 unilateral = 38 knees), it was found that a 90° knee extension caused the sagittal axis to displace anteriorly with a mean value of 20.0mm (SD=7.8). In comparison the 14 ACL deficient knees were found to have a mean anterior displacement of 9.2 mm (SD=8.0). A bilateral comparison of the 12 pairs of normal knees showed no significant difference between left and right sides (paired-t, p=0.99). However, a bilateral comparison of the 14 unilateral ACL deficient patients showed a significant difference between normal and injured sides (paired-t, p=0.00025). In this group, the normal knees axis at full extension had a mean location 28.9mm (SD=8.8) posterior to the front of the tibial plateau. In comparison the injured knees axis has a mean location 37.8 mm (SD=8.5) posterior to the front of the tibial plateau. Again, this was highly significant (paired-t, p=0.0001). Conclusion: These results indicate that normal knees have a mean forward roll of 20 mm for a 90° knee extension. In comparison ACL deficient knees have a reduced roll of 9.2 mm which occurs at the rear of the joint. This reduction in roll is consistent with the abnormal ligament biomechanics

We have investigated those factors which influence the range of movement after total knee arthroplasty, including sex, age, preoperative diagnosis and preoperative flexion deformity and flexion range. We also compared cemented and cementless tibial fixation, the influence of collateral ligament and lateral parapatellar releases and of replacement of the patella, and of the period of postoperative immobilisation. We reviewed 516 Johnson-Elloy (Accord) knee arthroplasties performed between 1982 and 1989, with a minimum follow-up of 12 months. The most important factors in the range of flexion achieved after arthroplasty are the diagnosis and the preoperative range of flexion. In patients with osteoarthritis there was a mean loss of flexion; in rheumatoid arthritis there was a mean gain. In both groups, the stiffer knees gained motion and the more mobile knees lost it. Post-operative range of motion was not influenced significantly by cement fixation, collateral ligament or patellar retinacular releases, prolonged immobilisation or patellar replacement

Introduction: Sock application is a daily task that can pose a dislocation risk to implanted hips. The aim of this study was to measure hip flexion and rotation using three seated techniques of sock application. Namely:- 1. The leg crossed in a “figure of four” technique, 2. The lean forward technique, and 3. using a specialised sock applicator (Foxy Sock Aid). Methods: The movement of 32 hips in 16 healthy male volunteers, aged 20–43, were assessed as socks were applied using the 3 techniques listed above. Hip flexion and axial rotation were measured with a “Polhemus Fastrak” magnetic tracking system. Data was recorded from magnetic sensors attached around the subjects femur and Iliac Spine. The sensors measurement accuracy was 0.15 degrees. Results: All measurements started with the subjects sitting with their hips in approximately 90 degrees of flexion. The mean (SD) additional flexion required for each of the 3 techniques were:- Cross leg = 57.2. 0. (13.7), Lean forward = 51.3. 0. (17.7), and Sock applicator = 11.2. 0. (7.2). Hence the sock applicator required 40.1 degrees less flexion (P< < 0.001) than the lean forward technique. The lean forward technique required 5.9 degrees less flexion (P=0.007) than the cross legged technique. The mean (SD) peak rotations for each of the 3 techniques were:- Cross leg = 35.1. 0. (9.8) external, Lean forward = 0.1. 0. (3.8) internal, and Sock applicator = 0.8. 0. (4.0) internal. Discussion: The sock applicator, when used correctly, requires very little hip flexion. When patients stop using the sock applicator, they should be encourage to use the lean forward technique, as this requires little axial rotation

The benefit of mobile-bearing mechanism in total knee arthroplasty (TKA) has been controversial. The aim of this paper is to analyse the rotation of polyethylene (PE) and its effect on the range of motion (ROM) in mobile-bearing, posterior stabilised TKA (LPS-Flex™, Zimmer Co. Ltd.). Thirty-four consecutive PS-Flex™ TKAs (28 patients) were analysed. Three tantalum markers were inserted in the PE and the tibia (one for medial side and two for lateral side; total six markers). The rotation of the PE and the tibia was analysed in fluoroscopically-controlled radiograph taken at one years in full extension, 90 degrees flexion and passive maximum flexion. The markers in the tibia were identifiable in 19 knees and the analysis was based on these knees. The tibia rotated internally relative to the femur by 7.1± 5.2 degrees (mean ± SD, range −1 to 20 degrees). The amount of tibial rotation has no correlation to ROM. The rotation of the PE relative to the femur was unpredictable showing three knees with external rotation and four knees without rotation (Average; 4.0 ± 4.5 degrees internal rotation). The rotation of the PE on the tibia was 4.2± 5.2 degrees and seven knees (37 %) showed no rotation and 12 knees (63 %) showed less than 5 degrees rotation. There was a positive correlation between the amount of PE rotation on the tibia and ROM, which approached to statistical significance (p = 0.0684). This study has demonstrated that the rotation of the PE on the tibial tray is generally small (< 5 degrees). Because not tibial internal rotation but PE movement on the tibia correlated to ROM, the essential benefit of the mobile-bearing mechanism could be to compensate the rotational mismatch between the components rather than to reproduce normal knee kinematics

To determine whether resection of osteophyte at TKR improves movement, 139 TKRs were performed on knees with pre-operative posterior osteophyte. Randomisation was to have either resection of distal femoral osteophyte guided by a custom made ruler or no resection. After preparation of the femoral bone cuts the ruler measuring 19 mm was placed just proximal to the posterior chamfer cut. The proximal end of this ruler marked the bone to be resected and this was performed using an osteotome at 45 degrees. Knees randomised to no resection had no further femoral bony cuts. Three months after implantation the patients had range of motion assessed. One hundred and fourteen suitable knees were assessed, with 59 knees (57 patients) in the resection group and 55 knees (54 patients) in the no resection group. Full extension was more likely in the resection group (62%) than the group without resection (41%)(p=0.08). Flexion to at least 110 degrees was, however, less in the resection group (37%) than the no resection group (54%) (p=0.09). Our study failed to show a statistically significant difference if the bony osteophyte is removed. There were however sharp trends, with statistically a one in ten chance these results would be different if the trial was repeated. Although there is no indication as to the cause of improved extension this could be explained by the release of the posterior capsular structures allowing full extension. The reduction in flexion is harder to explain and this may be due to increase in perioperative trauma and resultant swelling, possibly with fibrosis. Range of movement, particularly flexion, is known to improve up to 1 year post-operatively and assessment of these groups at that stage would be beneficial

Temporary immobilisation of joints can lead to permanent ankylosis or fusion. The aim of this study is to demonstrate that treatment of vertebral fractures by single level fusion and 2 level fixation preserves movement in the unfused lower motion segment after removal of metalwork. 12 consecutive thoracolumbar fractures were treated by posterior fixation over two motion segments with fusion of the upper injured segment. Average age 39 years (27–50yrs.) and 6 were male. L2 was most frequently affected (6) then T12 (3), L1(2) and L3(1). Using the Denis classification 9 were Burst type B, 1 was Burst type A and 2 were Compression type B. No patients had abnormal neurology or any other vertebral injury. All operations were performed by one surgeon (RC) within 7 days of injury. Metalwork bridging the injured vertebra was removed at mean 11 months (8–13 * one patient 27 months) and average follow up in this study was 12 months (2–40) after removal of metalwork. A simple pain questionnaire and flexion-extension radiographs were obtained. The average movement in the motion segment previously bridged by metalwork was 5 degrees (0–12). For comparison, the level below moved an average of 7 degrees (2–17). Kyphus angle was 11 degrees (1–18) on presentation corrected to 0 degrees at operation (−6 - +12) returning 1 year after removal of metalwork to 5 degrees (1–16). Pain scores (0–10) were measured retrospectively, prior to the accident mean 0(0–1) and at review 2.6 (0–6). Only one patient failed to return to previous employment. She had the highest pain score at 6, showed no movement at the bridged motion segment where removal of metalwork was delayed to 27 months

A Salter innominate osteotomy is used to treat acetabular dysplasia, but reports of its effects on the position of the femoral head are few and conflicting. Lateral shift would increase the resultant forces acting on the joint and be detrimental. We studied 15 Salter innominate osteotomies and demonstrated that a correctly performed osteotomy does not significantly alter the distance from the centre of the femoral head to the midline of the body. Stereophotogrammetry was used in three patients to delineate the axis of rotation of the distal acetabular fragment and determine the locus of movement of the centre of the femoral head about it. Our results explain why the Salter osteotomy does not lateralise the femoral head

Introduction and Objective: Although the causation and progression of adolescent idiopathic scoliosis (AIS) remains unclear, a recent review has highlighted a series of possible aetiological factors. Additionally, research investigations have indicated that the kinematic differences in various body segments may be a major contributing factor. The value of gait analysis systems employed to measure dynamic back movements in furthering understanding of spinal deformity has also been demonstrated by various studies. Research employing gait measurements have indicated asymmetries in the ground reaction forces and have suggested relationship between these asymmetries, neurological dysfunction and spinal deformity. This investigation, which formed part of a wider comprehensive study, was aimed at identifying asymmetries in lower limb kinematics and pelvic and back movements during level walking in scoliotic subjects that could be related to the spinal deformity. Design and Methodology: The research employed a movement analysis system and a strain gauge force platform to estimate time domain kinetic parameters and other kinematic parameters in the lower extremities, pelvis and back. 16 patients with varying degrees of deformity, scheduled for surgery within a week took part in the study. Results and conclusions: The findings have demonstrated the presence of asymmetries in kinetic parameters in the scoliotic subject and have also served to highlight the value of using kinetic and kinematic parameters in developing the understanding of the pathogenesis and aetiology of scoliosis. In addition, the results have also indicated that the variables identified in the study can be applied to initial screening and surgical evaluation of spinal deformities such as scoliosis. Further studies are being undertaken to validate these findings

The presented study investigated the difference of positioning sense of the shoulder before and after surgery (capsular shift or Arthroscopic Bankart repair) for shoulder instability. For this purpose a sample of patients with recurrent dislocations of the shoulder that underwent surgery and patients with instability before surgery volunteered to participate in a set of experiments. Their results were compared to the results obtained from a matching sample of healthy subjects. All subjects completed all movement’s conditions that included the performance of hand movements towards memorized visual target in A-horizontal plane condition and B-Three dimensional movement condition. The mixed design (3 groups x 3 2D levels x 3 3D levels) with repeated measures allowed the comparison among the groups in terms of final accuracy measures (Absolute and Variable Errors) and variability around mean tangential velocities and end-point paths. The results showed that operative shoulder stabilization improves the ability to accurately position the arm on a target at the end of the movement and in addition the kinematic profile, which is disturbed before stabilization, improves as well. These measures may be used as an objective tool to asses the success of conservative as well as operative treatment for shoulder instability

Dislocation is the most frequent serious complication following total hip replacement for subcapital femoral fracture. We report a prospective study, using matched groups, which compared the range of hip movement following hip replacement for arthritis and for fracture. The range of movement was significantly greater in the fracture group. We suggest that this is a predisposing factor for dislocation

Purpose and Background. This pilot study aimed to determine the accuracy of lumbar spine combined movement (CM) testing for diagnosing facet joint mediated pain, by comparing CM to medial branch blocks (MBB) - the gold standard in the diagnosis of facet joint pain. A regular compression pattern of CM combines active extension and lateral flexion, which is believed to compress the facet joints greater than physiological uni-planar movements. Method and Results. 96 patients attending a pain clinic day case unit for diagnostic MBB were recruited. Patients' pain responses to CMs were measured prior to and thirty minutes following MBB. The effect of weight bearing and recumbence, RMDQ, EQ-5D and MYMOP were also measured. The regular compression CM test had 80% sensitivity (95%CI: 71% to 89%) and 50% specificity (95%CI: 28% to 71%). The regular compression CM group had the largest pre-post VAS difference (median 4 points). The patients whose pain was not relieved in recumbence (n=15) showed a significant VAS difference of 6 points p=0.001). There was a significant positive correlation between the pre and post pain scores, p<0.001. There was no association between MBB response and RMDQ, EQ-5D, MYMOP scores, duration of symptoms or standing as a provoking activity. Conclusion. Regular compression CM testing can be used as a diagnostic tool to identify patients with facet joint mediated pain, particularly when associated with high pain scores. Low back pain (LBP) provoked by standing and relieved with recumbence are common features in the LBP population but are not indicators of facet joint pathology, contrary to many clinicians' beliefs

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

We performed CT myelography in 38 patients with cervical myelopathy before and after laminoplasty to enlarge the canal. The sagittal and transverse diameters, the cross-sectional area, and the central point of the spinal cord were measured. After cervical laminoplasty, the mean sagittal diameter of the spinal cord at C5 increased by 0.8 mm, but the mean transverse diameter decreased by 0.9 mm. The mean cross-sectional area of the cord increased by 7.4% and that of the dural sac and its contents by 33.8% at C5. The centre of the spinal cord moved a mean 2.8 mm posteriorly at this level. Enlargement of the spinal canal is sufficient to decompress the spinal cord, but posterior movement may be the limiting factor in determining the decompressive effect of laminoplasty

Background. Shoulder pain limits range of motion (ROM) and reduces performing activities of daily living (ADL). Objective assessment of shoulder function could be of interest for diagnosing shoulder pathology or functional assessment of the shoulder after therapy. The feasibility of 2 wearable inertial sensors for functional assessment to differentiate between healthy subjects and patients with unilateral shoulder pathology is investigated using parameters as asymmetry. Methods. 75 subjects were recruited into this study and were measured for at least 8 h a day with the human activity monitor (HAM) sensor. In addition, patients completed the Disability of the Arm, Should and Hand (DASH) score and the Simple Shoulder Test (SST) score. From 39 patients with a variety of shoulder pathologies 24 (Age: 53.3 ± 10.5;% male: 62.5%) complete datasets were successfully collected. From the 36 age-matched healthy controls 28 (Age: 54.9 ± 5.8;% male = 57.1%) full datasets could be retrieved. Activity parameters were obtained using a self-developed algorithm (Matlab). Outcome parameters were gyroscope and accelerometry-based relative and absolute asymmetry scores (affected/unaffected; dominant/non-dominant) of movement intensity. Results & Discussion. The absolute and relative asymmetry scores of the accelerometry-based intensity results for a threshold of > 0.1 g (AUC 0.821 and AUC 0.827) proved to be slightly more distinctive to the gyroscope-based intensity results for a threshold of > 10 deg/s (AUC 0.807 and 0.795) to distinguish between the healthy group and the shoulder group. Asymmetry (< 1%) was nearly absent in healthy controls (5/56 subjects) using the accelerometry-based intensity (> 0.1g) results but common in patients (29/48 subjects). A moderate, significant correlation was found between the asymmetry scores and the DASH score, thus complementary use is advised. The asymmetry scores had no correlation to the SST score. Conclusion. Ambulant assessment of shoulder activity using human activity monitors, containing a gyroscope and accelerometer, during ADL is feasible. The accelerometry-based and gyroscope-based absolute and relative asymmetry scores are promising parameters to diagnose or assess function of the shoulder. A moderate correlation was found between the DASH score and the activity monitor parameters, suggesting both could be used complementary to assess function

This study looks at the dynamic tendon-to-bone contact properties of rotator cuff (RC) repairs—comparing single row repairs (SRR) with double row transosseous- equivalent (TOE) repairs. It was postulated that relaxation during, and movement following, the repair would significantly compromise contact properties and therefore, the ability of the tendon healing. Simulated tears were created in the supraspinatus tendon of six cadaveric human shoulders. A SRR was then performed using the OPUS System, creating two horizontal mattress sutures. An I-Scan electronic pressure-sensor (Tekscan, Boston, MA) was placed between the supraspinatus tendon and bone. The arm was then rested for 300secs (relaxation) before being passively moved twice through a range-of-motion (0-90 degrees abduction, 0-45 external and 0-45 internal rotation) and finally returned to neutral. The contact properties were recorded throughout each movement. The procedure was then repeated using two TOE techniques: parallel sutures (TOE-P) and a cross over suture pattern (TOE-C). While peak pressures during the repair were higher in the two TOE repairs, all three methods demonstrated relaxation over 300s such that there was no significant diference in contact pressures at the end of this time. TOE parallel and cross-over repairs demonstrated no significant change in mean TTB contact pressure, force and area during abduction, external rotation and return to neutral, when compared to the 300sec relaxation state. TOE-C demonstrated a higher contact force on internal rotation (+53%). The SRR demonstrated a significant drop in contact force on abduction (−63%), and return to neutral (−43%) and a trend on external rotation (−34%). SRR exhibited no change on internal rotation. There have been very few biomechanical studies with which observe RC repair contact properties dynamically. Relaxation of the repair can be partially reversed. Significant decrease in contact area with SRR during movement occurred, compared to the TOE repairs, which remains unaltered. This is an important consideration when determining postoperative rehabilitation

Objective

There is limited information about the extent to which the association between pre-operative and chronic post-operative pain is mediated via pain-on-movement or pain-at-rest. We explored these associations in patients undergoing total hip (THR) and total knee (TKR) replacement.

Summary. Movement analysis (IMA) and activity monitoring (AM) using a body-fixed inertia-sensor can discriminate patients with ankle injuries from controls and between patients of different pathology or post-injury time. Weak correlations with PROMs show its added value in objectifying outcome assessment. Introduction. Ankle injuries often result in residual complaints calling for objective methods to score outcome alongside subjective patient-reported outcome measures (PROMs). Inertial motion analysis (IMA) and activity monitoring (AM) using a body-fixed sensor have shown clinical validity in patients suffering knee, hip and spine complaints. This study investigates the feasibility of IMA and AM 1) to differentiate patients suffering ankle injuries from healthy controls, 2) to compare different ankle injuries, 3) to monitor ankle patients during recovery. Methods. 32 patients suffering ankle problems (ankle sprain, n=17, 42 ±26yrs; operatively managed ankle fracture, n=15, 44 ±17yrs) during short-term recovery (6weeks to 3months post-trauma) were compared to 22 matched healthy controls (41 ±13yrs). Function was measured using IMA: Gait, Sit-Stand (STS) and 10s one-leg Balance test (OLB) were performed while wearing a 3D inertia-sensor at the lower back. Physical activity was measured during 4 successive days using a 3D accelerometer (AM), attached at the upper leg. Validated algorithms were used to derive motion parameters (e.g. speed for gait, bending angle for STS, sway area for OLB, # steps for AM). Moreover three ankle specific questionnaires were completed: Manchester-Oxford Foot and Ankle Questionnaire (MOXFQ), Foot and Ankle Ability Measure (FAAM), AOFAS ankle-hindfoot score. Data was analysed using paired t-tests, one-way ANOVA and Pearson's r. Results. Both patient groups performed worse in function (IMA), activity (AM) and scales (PROM). Even at 3 months mean walking speed (−26%) and cadence (−9%) were slower while pelvic obliquity during ST (+18%) and sway during OLB (+230%) was higher than in controls (p<0.05). Activity was less regarding step/day (−31%) and sit-stand transfers (−11%, p<0.05). Also PROMs were significantly worse in patients (range 17–37%). Comparing in-between patients, significant differences were found in PROMs and function (IMA) with fracture patients walking slower (−30%) or showing more sway during one-legged balance (+250%). Mean activity scores (steps, bouts, cadence) were also less for fractures (p>0.05). During recovery, PROMs improved significantly, while function (IMA) and activity (AM) only showed small or selective improvements (e.g. 8° reduction in bending angle during ST, 20% increase in cadence). Only weak to moderate correlations were found between PROM, IMA (r-range: 0.32–0.79) and AM parameters (r-range: 0.31–0.71). Discussion & Conclusion. Function, physical activity and PROMs were impaired in patients with ankle injuries compared to healthy subjects, with the fracture group performing worse on IMA and PROMs than the sprain group. In this first study ever to measure activity in ankle patients, it was shown that e.g. fracture patients walk ca. half as many steps and bouts as age-matched controls even though at 6weeks they were unable to walk 20m without walking aids (floor effect of IMA function test). The lack of improvements in IMA and AM during recovery while PROMs improved significantly, together with the few and only weak-to-moderate correlations between PROMs, IMA and AM shows that subjective and objective recovery differ and highlight the added value of IMA and AM for objectifying routine clinical outcome assessment

Introduction. Regular, repeated stretching increases joint range of movement (RoM), however the physiology underlying this is not well understood. The traditional view is that increased flexibility after stretching is due to an increase in muscle length or stiffness whereas recent research suggests that increased flexibility is due to modification of tolerance to stretching discomfort/pain. If the pain tolerance theory is correct the same degree of micro-damage to muscle fibres should be demonstrable at the end of RoM before and after a period of stretch training. We hypothesise that increased RoM following a 3 weeks hamstrings static stretching exercise programme may partly be due to adaptive changes in the muscle/tendon tissue. Materials and Methods. Knee angle and torque were recorded in healthy male subjects (n=18) during a maximum knee extension to sensation of pain. Muscle soreness (pain, creatine kinase activity, isometric active torque, RoM) was assessed before knee extension, and 24 and 48 hours after maximum stretch. An exercise group (n=10) was given a daily home hamstring stretching programme and reassessed after 3 weeks and compared to a control group (n=8). At reassessment each subject's hamstring muscles were stretched to the same maximum knee extension joint angle as determined on the first testing occasion. After 24 hours, a reassessment of maximum knee extension angle was made. Results. At the start of the study RoM was 71.3 ± 10.0 degrees and there was no significant difference between groups. After 3 weeks stretching RoM increased significantly (p=0.01) by 9 degrees; the control group showed no change. Stiffness did not differ for either group. Pain score and RoM were the most sensitive markers of muscle damage and were significantly changed 24 and 48 hours after the initial stretch to end of range, (p<0.005) and (p=0.004) respectively. Discussion. The results show that a 3 week stretching programme causes muscle adaptation resulting in an increase in the extensibility of the hamstring muscle/tendon unit but no change in stiffness. The lack of evidence of muscle damage suggests that participants in the stretching group are likely to have undergone a physical change/adaptation rather than simply an increase in pain threshold

We studied 27 patients with low back pain and unilateral L5 or S1 spinal nerve root pain. Significant radiological changes were restricted to the symptomatic root level, when compared with controls. Low back and leg pain were graded on a visual analogue scale. Dermatomal quantitative sensory tests revealed significant elevations of warm, cool and touch perception thresholds in the affected dermatome, compared with controls. These elevations correlated with root pain (warm v L5 root pain; r = 0.88, p < 0.0001), but not with back pain. Low back pain correlated with restriction of anteroposterior spinal flexion (p = 0.02), but not with leg pain. A subset of 16 patients underwent decompressive surgery with improvement of pain scores, sensory thresholds and spinal mobility. A further 14 patients with back pain, multilevel nerve root symptoms and radiological changes were also studied. The only correlation found was of low back pain with spinal movement (p < 0.002). We conclude that, in patients with single level disease, dermatomal sensory threshold elevation and restriction of spinal movement are independent correlates of sciatica and low back pain

Purpose of the study: The objective was to analyse shoulder motion, particularly abduction and anterior elevation, in patients with an reversed prosthesis. A radiocinematographic study enable an analysis of the movements of the prosthesis it self and movements due to scapulothoracic participation. Material and methods: This study was based on the analysis of 33 patients with an reversed shoulder prosthesis. A videoscopic recording (25 images per second) of anterior elevation from a workstation used for abduction arteriography was used. The Constant score was noted and a standard x-ray work-up (four views) was obtained for all patients. Results: The cohort was a homogeneous continuous series of 21 women and 12 men, mean age 72.5 years (range 39–84). Two modes of motion were observed. The first (group 12, n=17 shoulders) was «monoarticular»: shoulder motion was almost exclusively related to movement of the scapulothoracic junction. Abduction did not exceed 90°. The second mode (group 2, n=16 shoulders) was «bi-articular»: joint motion began with the prosthesis (50° on average) followed by scapulothoracic participation (50° on average). The implant then was involved in the final part of the motion (in six of the 16 shoulders in group 2) to complete the range of motion exceeding 120° abduction and anterior elevation. Discussion: This study confirmed the presence of an initial intrinsic mobility of the prosthesis followed by scapulothoracic participation. It was noted however, that for the majority of cases, the intrinsic mobility of the prosthesis was limited. In all cases, the range of motion recorded by clinical examination was greater than the range of motion measured objectively by radiocinematography. Discussion: This study demonstrated the in vivo mobility of the reversed prosthesis. However, a range of motion greater than 100° anterior elevation and abduction is exceptional. Clinical findings reflect imperfectly the real mobility of this type of prosthesis

In six unloaded cadaver knees we used MRI to determine the shapes of the articular surfaces and their relative movements. These were confirmed by dissection. Medially, the femoral condyle in sagittal section is composed of the arcs of two circles and that of the tibia of two angled flats. The anterior facets articulate in extension. At about 20° the femur ‘rocks’ to articulate through the posterior facets. The medial femoral condyle does not move anteroposteriorly with flexion to 110°. Laterally, the femoral condyle is composed entirely, or almost entirely, of a single circular facet similar in radius and arc to the posterior medial facet. The tibia is roughly flat. The femur tends to roll backwards with flexion. The combination during flexion of no antero-posterior movement medially (i.e., sliding) and backward rolling (combined with sliding) laterally equates to internal rotation of the tibia around a medial axis with flexion. About 5° of this rotation may be obligatory from 0° to 10° flexion; thereafter little rotation occurs to at least 45°. Total rotation at 110° is about 20°, most if not all of which can be suppressed by applying external rotation to the tibia at 90°

Purpose. To describe the frequency of different patterns of pain response and their association with outcomes (prognosis) and MRI findings in patients experiencing sciatica. Methods. 176 consecutive consenting patients with radicular pain underwent an MRI and a clinical assessment at baseline using a standardized procedure of repeated lumbar movements and positioning guided. Based on their pain response, patients were divided into five groups: abolition centralization, reduction centralization, unstable centralization, peripheralization, and no effect on pain. Results. Overall, 84.8 % of patients reported experiencing one of the three forms of centralization, 7.3 % reported peripheralization and 7.9 % reported “No effect”. The median reduction in RMQ scores across all three centralization groups was 9.5 points at 3-months and 12.0 points at 12-months. The peripheralization group improved by a similar amount (7.0 and 14.0 respectively). In contrast, the ‘no effect’ group improved by 3.0 at both time points and this was significantly different (p<0.001) from the other groups. These results were mimicked in relation to leg pain. In addition, there was no association between the reported pain responses (centralization, peripheralization or no effect) and the type of disc lesion observed on MRI. Conclusion. In patients with sciatica, centralization was common. Centralization and peripheralization at baseline were equally associated with improvement in activity limitation and leg pain over time. As there was no association between MRI findings and the pain response to movement, these results do not support the belief that centralization only occurs if the annulus is intact and the intra-discal hydrostatic mechanism is functional

Background: The main aim of this study is to compare the difference between early mobilisation versus non weight bearing in patients post ankle fracture fixation in terms of pain and functional outcome. Methods: We recruited 60 patients and were divide into two equal groups. Patients in Group A were treated with a below knee cast post ankle fracture fixation and remained non weight bearing for six weeks while groub B were patients that were treated with a backslab for two weeks post fixation. The backslab was removed and once their radiographs were deemed satisfactory, They were referred to the physiotherapy service in our unit for range of motion exercises while still remaining non-weight bearing. All patients were allowed to weight bear at six weeks time post fixation. The inclusion criteria included patients within the age of 18 to 40 years of age and all the fractures are classified using the Weber classification. Patients that were excluded from theses studies are those with unstable fractures and have high co-morbid conditions. All these patients were followed up at 2 weeks, 6 weeks, 3 months and 9 months post ankle fracture fixation. Pain and functional outcome were scored using the AOFAS scoring system. Results: We found that patients in both these groups scored almost equally during the 2 week follow up but at 6 week, group B showed much better range of movement with less pain and a much higher satisfaction rate with their range of movement. However, at 9 months, patients in both group were able to return to their normal physical activity. Conclusion: Our conclusion is that early mobilisation has an definite advantage over non weight bearing post ankle fracture with regards to functional outcome, pain scoring and patient satisfaction. Patient selection and compliance play a role in the outcome of the study

Kinematics of the knee change during the full range of flexion [1]. The lateral femoral condyle (LFC) rolls back progressively through the entire range of flexion. The medial femoral condyle (MFC) does not move back during the first 110 degrees, but from 110 to 160 degrees it moves back by 10mm. This dual arc makes anatomical knee design a challenging task. In medial rotation, during flexion, the MFC stays in place, but the LFC moves forward in extension and backward in flexion. In lateral rotation the LFC stays still while the MFC moves back and forward in flexion and extension. During central rotation both condyles move reciprocally. However the knee is stable against an anteriorly or posteriorly directed force. It is important that all these degrees of freedom and stability are reproduced in total knee replacement (TKR) design.

Furthermore, the two femoral condyles together form a spiral. Like the threads of a screw in a nut they allow medio-lateral translation of the femur [2] in the tibial reference frame. During flexion the knee centre moves laterally nearly 20% of the width of the tibial plateau and in extension the femur translates medially. This medio-lateral translation occurs in the natural normal knee joint. This has special significance in knee design because the natural femur (along with the trochlea) moves laterally in flexion, allowing the patella to be sited laterally, while most regular TKRs drive the patella medially. In order to test this anomaly we studied patellar maltracking in vivo and in cadavers.

In vivo tracking studies using a patellar tracker during total knee replacement demonstrated average patellar maltracking of 10mm with regular TKR designs. Experiments on 22 cadaveric limbs using loaded quadriceps mechanism and trackers on the femur, tibia and patella, showed that in the natural knee the patella tracked medially by an average of 5mm. In regular TKRs the patella tracked medially. Compared to a normal knee, the patella in these designs maltracked on average by 10mm. Spiral condyles applied to the same bone cuts in the cadavers allowed the patella tracking to return to the expected lateral position in flexion.

This has application to total knee replacement design. Unless the spiral design is incorporated in the condyles, patellar maltracking is inevitable and is likely to cause lateral knee pain and stiffness post-operatively.

We used roentgen stereophotogrammetric analysis to follow 33 C-stem femoral components for two years after primary total hip arthroplasty. All components migrated distally and posteriorly within the cement mantle. The mean distal migration was 1.35 mm (sd 0.62) at two years and the mean posterior migration was 1.35 mm (sd 0.69) at two years. All the femoral components rotated into retroversion with a mean rotation at two years of 1.9° (sd 1.1). For all other directions, the prosthesis was stable up to two years. Compared with other tapered prostheses, the distal migration of the C-stem is the same, but posterior rotation and posterior migration are greater.

Introduction: The Oxford unicompartmental knee replacement (UKR) use in the lateral compartment has been associated with a reduced flexion range and increased medial compartment pain than seen with its medial counterpart due to, in part, the inadequacy of a flat tibial tray replacing the domed anatomy of the lateral tibia. A new design incorporating a domed tibial component and a biconcave meniscal bearing has been developed to overcome these problems. This study reports a clinical comparison of new and old establishing whether this modified implant has maintained the established normal kinematic profile of the Oxford UKR. Method: Patients undergoing lateral UKR for OA were recruited for the study. Fifty one patients who underwent UKR with the domed design were compared to 60 patients who had lateral UKR with a flat inferior bearing surface. Kinematic evaluation was performed on 3 equal subgroups (n = 20); Group 1-Normal volunteer knees, Group 2-Flat Oxford Lateral UKR’s and Group 3-Domed Oxford Lateral UKR’s. The sagittal plane kinematics of each knee was assessed using videofluoroscopic analysis whilst performing a step up and deep knee bend activity. The fluoroscopic images were recorded digitally, corrected for distortion using a global correction method and analysed using specially developed software to identify the anatomical landmarks needed to determine the Patella Tendon Angle (PTA) (the angle the patella tendon and the tibial axis). Knee kinematics were assessed by analysing the movement of the femur relative to the tibia using the PTA. Results: PTA/KFA values, for both devices, from extension to flexion did not show any significant difference in PTA values in comparison to the normals as measured by a 3-way ANOVA. The Domed implant achieved higher maximal active flexion during the lunge exercise than those with a flat implant. Only 33% of the flat UKR’s achieved KFA of 130° or more under load whilst performing a lunge, compared with 75% of domed UKR’s and 90% of normal knees. No flat UKR achieved a KFA of 140° or more, yet 50% of all domed UKR’s did, as did 60% of all normal knees. Conclusions: There was no significant difference in sagittal plane kinematics of the domed and flat Oxford UKR’s. Both designs had favorable kinematic profiles closely resembling that of the normal knee, suggesting normal function of the cruciate mechanism. The domed knees had a greater range of motion under load compared to the flats, approaching levels seen with the normal knee, suggesting that limited flexion for the flat plateau results from over tightening in high flexion and that this is corrected with the domed plateau. Problems with the second generation of lateral Oxford UKA have been rectified by a new bi-concave bearing without losing bearing stability and normal kinematics

A new generation of knee prostheses has been introduced with the intention of improving post-operative knee flexion. In order to evaluate whether this goal has been achieved we performed a systematic review and meta-analysis. Systematic literature searches were conducted on MEDLINE and EMBASE from their inception to December 2007, and proceedings of scientific meetings were also searched. Only randomised, clinical trials were included in the meta-analysis. The mean difference in the maximum post-operative flexion between the ‘high-flex’ and conventional types of prosthesis was defined as the primary outcome measure. A total of five relevant articles was identified.

Analysis of these trials suggested that no clinically relevant or statistically significant improvement was obtained in flexion with the ‘high-flex’ prostheses. The weighted mean difference was 2.1° (95% confidence interval −0.2 to +4.3; p = 0.07).

Introduction

Biomechanists have been trying to obtain integrated and accurate human motion data. However, it is not so easy, because some have limitation of accuracy, some have limitation of the observation area, and some are expensive.

For example, motion capturing can obtain whole body motion data, but needs space, is expensive, but only surface motion could be obtained. So is not so sensitive for the bone rotation. Sensors of pressure, acceleration, and so forth are less expensive and less hard to use, but the data are limited. 2D–3D shape matching such as Jointtrack can describe bone motion including rotation, but the detectable area is limited by the size of flat panel fluoroscopy.

In this study, we have combined multiple joint motion analysis by Jointtrack and reconstructed full lower extremities' motion.

The concept that fluid percolating through bone matrix is the basis for mechanotransduction of stress stimuli to modeling and remodeling has proved challenging⁴. Traditional solid mechanical models in which piezoelectricity is the mechanotransduction process are more intuitive to orthopaedic practitioners nurtured on the fundamentalism of Wolff’s “Law”. However, the scientific evidence from Anderson and Ericksson¹, Piekarski and Munro⁵, and Hillsley and Frangos³ strongly support a bone fluid flow (BFF) paradigm, which, when coupled with the Utah paradigm of Frost² forms the most scientifically validated explanation to date of osteon response to mechanical stress in vivo.

In order to make this explanation more intuitive we have developed a metaphorical rendering of the model. The rendering adds an extension to include our current model for the effects of skeletal muscle contraction on the basic multicellular unit (BMU). In the metaphor, cortical bone is the continent nation HaroldFrostland. Its cities are fed by waterways which serve as metaphors for each of the fluid transporting pathways from arteries to inter-collagen spaces of bone matrix.

Bounding the continent are oceans wherein underwater earthquakes—metaphors for skeletal muscle contractions—generate solitary pressure waves (tsunamis) and a ripple effect in continental waterways. Critical for penetration by and effectiveness of such solutions is that flow resistance in the waterways must allow pressure buildup. Locks/valves serve to provide this resistance. When pressure is sufficient filtration at transfer points—metaphors for where nutrient exchange occurs--is enhanced. By this means, muscle contraction enhances delivery of fluid not only to bone cells; but around them as well, stimulating mechanotransduction.

INTRODUCTION: In total knee arthroplasty (TKA) it still remains undecided whether the patella should be resurfaced or not. This study used two accelerometer based motion analysis systems to study if functional tests are able to detect a difference in patients with or without a resurfaced patella.

METHOD: Retrospective study of a cohort of 53 unilateral TKA patients (Stryker Scorpio). With one surgeon always resurfacing and the other one routinely retaining the patella, patients were divided into a resurfaced group (RS, n=31) and a non-resurfaced group (NR, n=22).

Patients were clinically assessed for 2 years using the Knee Society Score (KSS). At final follow-up patients were assessed once using two accelerometer based motion tests (Dynaport Knee Test and Minimod Gait Test; McRoberts, Netherlands). The knee score is composed of four sub scores (Locomotion, Rise & Descend, Transfers, Lift & Move). The gait test records walking parameters such as step frequency, length and speed plus various parameters of step asymmetry, irregularity and efficiency. Statistical analysis was performed using the van Elteren’s test (KSS data) and a stratified regression analysis (Dynaport and Minimod data)

RESULTS: The mean pre-op KSS was not different between the groups (RS=42.7+/−16.5, NS=50.5+/−13.8, p=0.08). Differences remained non-significant post-op at three months (RS=42.7+/−16.5, NS=50.5+/−13.8, p=0.08), at final follow-up (RS=42.7+/−16.5, NS=50.5+/−13.8, p=0.08) and regarding total improvement (RS=8.7, NS=5.1, p=0.29).

The Dynaport knee test showed a significant functional advantage for patella resurfacing (RS=44.1+/−12.1, NR=39.7+/−19.2, p=0.04). The sub score Rise & Descend showed the largest advantage for patella resurfacing (RS=44.7, NR=39.7, p=0.04). The other sub scores also favored resurfacing but were not significant. The Minimod Gait test favoured RS in most parameters but at non-significant levels.

DISCUSSION: Using the KSS it was not possible to identify resurfacing or retaining the patella as the superior choice in TKA. However, using performance based tests it was possible to measure significant differences in favour of patella resurfacing but only when the motion tasks were most demanding and depending on patella-femoral function such as during Rise & Descend (stair climbing, slope walking, stepping onto blocks). This indicates a relevant functional benefit of patella resurfacing for the patient. Functional parameters derived from less demanding tasks such as normal gait (Mini-mod) could not verify this benefit.

The advantage of patella resurfacing may be less due to pain relief but due to a functional benefit during demanding motion tasks for which standard clinical scores and low demanding tests do not account for sufficiently and objectively enough. We recommend complementing the classic evaluation tools with demanding functional tests.

Aim: To find out when, at which interface, and to what extent migration of the Exeter stem after revision with morselized allograft bone and cement takes place and to evaluate if restricted weight bearing had any influence on the migration pattern. Methods: 40 stem revisions were followed by radiostereometry (RSA). The surgical procedure described by the Exeter group in England (Gie et al 1993) was used. Results: Most migration occurs within the first weeks after surgery. The Exeter stem migrates “within” the cement mantle and the stem-cement beam also migrates relative to femur.

All stems migrated distally and most of them also migrated medially or laterally and posteriorly. Migration was still observed in one third of stems between 1.5 and 2-year follow-ups. At 2 years stem subsidence averaged 2.5 mm, medial or lateral migration averaged 1.2 mm and posterior migration averaged 2.9 mm. No correlation to the preoperative bone stock deficiency was observed. Between 2 and 5 years only marginal migration occurred in 11 of the 15 stems followed for 5 years.

No differences in the migration pattern were detected when free weight bearing was allowed immediately after revision in hips without intraoperative skeletal complications as compared to when restricted weight bearing was practiced. No rerevision was performed. Conclusions: Most migration occurs early. Subsidence occurs of the stem within the cement mantle and of the stem-cement beam. Many stems migrate marginally even after 2 years but this does not deteriorate the results during the first five years. Restricted weight bearing postoperatively in uncomplicated cases might not be needed.