Biocompatibility of Antifogging SiO-doped Diamond-Like Carbon Laparoscope Coatings.

Laparoscopes can suffer from fogging and contamination difficulties, resulting in a reduced field of view during surgery. A series of diamond-like carbon films, doped with SiO, were produced by pulsed laser deposition for evaluation as biocompatible, antifogging coatings. DLC films doped with SiO demonstrated hydrophilic properties with water contact angles under 40°. Samples subjected to plasma cleaning had improved contact angle results, with values under 5°. Doping the DLC films with SiO led to an average 40% decrease in modulus and 60% decrease in hardness. Hardness of the doped films, 12.0 - 13.2 GPa, was greater than that of the uncoated fused silica substrate, 9.2 GPa. The biocompatibility was assessed through CellTiter-Glo assays, with the films demonstrating statistically similar levels of cell viability when compared to the control media. The absence of ATP released by blood platelets in contact with the DLC coatings suggests in vivo hemocompatibility. The SiO doped films displayed improved transparency levels in comparison to undoped films, achieving up to an average of 80% transmission over the visible spectrum and an attenuation coefficient of 1.1 × 104 cm-1 at the 450 nm wavelength. The SiO doped DLC films show promise as a method of fog prevention for laparoscopes.

Focused Assessment with Sonography in Trauma (FAST) performance in paediatric conflict injury.

AIM: To evaluate the efficacy of Focused Assessment with Sonography in Trauma (FAST) in a paediatric population with a substantial proportion of penetrating abdominal injuries. MATERIALS AND METHODS: FAST and computed tomography (CT) abdomen findings were compared for 98 children who presented to Camp Bastion during the war in Afghanistan in 2011. FAST performance was compared to the reference standard of free fluid detected on CT. Whether children presented alone or as part of a group was also ascertained from the radiology database. RESULTS: Of the 98 patients, 20 had free fluid on CT and 15 were FAST positive. Fourteen of the 98 (14%) had penetrating wounds to the abdominal cavity. For the whole cohort FAST sensitivity was 65% (41-85%) and specificity 97% (91-100%). For those with penetrating abdominal injury sensitivity was 64% (31-89%) and specificity was 100% (40-100%). In total, 45% arrived at the same time as another casualty, and 30% arrived with other injured children. CONCLUSION: FAST performance in this population was similar to that reported in the context of paediatric blunt trauma, with high specificity for intra-abdominal free fluid. This is the first time this has been demonstrated in a cohort containing children with penetrating abdominal trauma. A substantial proportion of children presented as part of a group, necessitating simultaneous triage of multiple injured patients. FAST has a role to play in conflict medicine and mass casualty scenarios where rapid access to CT may not be feasible.

Skin and soft tissue infections and current antimicrobial prescribing practices in Australian aged care residents.

To determine the burden of skin and soft tissue infections (SSTI), the nature of antimicrobial prescribing and factors contributing to inappropriate prescribing for SSTIs in Australian aged care facilities, SSTI and antimicrobial prescribing data were collected via a standardised national survey. The proportion of residents prescribed ⩾1 antimicrobial for presumed SSTI and the proportion whose infections met McGeer et al. surveillance definitions were determined. Antimicrobial choice was compared to national prescribing guidelines and prescription duration analysed using a negative binomial mixed-effects regression model. Of 12 319 surveyed residents, 452 (3.7%) were prescribed an antimicrobial for a SSTI and 29% of these residents had confirmed infection. Topical clotrimazole was most frequently prescribed, often for unspecified indications. Where an indication was documented, antimicrobial choice was generally aligned with recommendations. Duration of prescribing (in days) was associated with use of an agent for prophylaxis (rate ratio (RR) 1.63, 95% confidence interval (CI) 1.08-2.52), PRN orders (RR 2.10, 95% CI 1.42-3.11) and prescription of a topical agent (RR 1.47, 95% CI 1.08-2.02), while documentation of a review or stop date was associated with reduced duration of prescribing (RR 0.33, 95% CI 0.25-0.43). Antimicrobial prescribing for SSTI is frequent in aged care facilities in Australia. Methods to enhance appropriate prescribing, including clinician documentation, are required.

Experimental platforms to study blast injury.

Injuries sustained due to attacks from explosive weapons are multiple in number, complex in nature, and not well characterised. Blast may cause damage to the human body by the direct effect of overpressure, penetration by highly energised fragments, and blunt trauma by violent displacements of the body. The ability to reproduce the injuries of such insults in a well-controlled fashion is essential in order to understand fully the unique mechanism by which they occur, and design better treatment and protection strategies to alleviate the resulting poor long-term outcomes. This paper reports a range of experimental platforms that have been developed for different blast injury models, their working mechanism, and main applications. These platforms include the shock tube, split-Hopkinson bars, the gas gun, drop towers and bespoke underbody blast simulators.

Central line-associated bloodstream infections in Australian ICUs: evaluating modifiable and non-modifiable risks in Victorian healthcare facilities.

Central line-associated bloodstream infections (CLABSIs) in intensive care units (ICUs) result in poor clinical outcomes and increased costs. Although frequently regarded as preventable, infection risk may be influenced by non-modifiable factors. The objectives of this study were to evaluate organisational factors associated with CLABSI in Victorian ICUs to determine the nature and relative contribution of modifiable and non-modifiable risk factors. Data captured by the Australian and New Zealand Intensive Care Society regarding ICU-admitted patients and resources were linked to CLABSI surveillance data collated by the Victorian Healthcare Associated Infection Surveillance System between 1 January 2010 and 31 December 2013. Accepted CLABSI surveillance methods were applied and hospital/patient characteristics were classified as 'modifiable' and 'non-modifiable', enabling longitudinal Poisson regression modelling of CLABSI risk. In total, 26 ICUs were studied. Annual CLABSI rates were 1·72, 1·37, 1·00 and 0·93/1000 CVC days for 2010-2013. Of non-modifiable factors, the number of non-invasively ventilated patients standardised to total ICU bed days was found to be independently associated with infection (RR 1·07; 95% CI 1·01-1·13; P = 0·030). Modelling of modifiable risk factors demonstrated the existence of a policy for mandatory ultrasound guidance for central venous catheter (CVC) localisation (RR 0·51; 95% CI 0·37-0·70; P < 0·001) and increased number of sessional specialist full-time equivalents (RR 0·52; 95% CI 0·29-0·93; P = 0·027) to be independently associated with protection against infection. Modifiable factors associated with reduced CLABSI risk include ultrasound guidance for CVC localisation and increased availability of sessional medical specialists.

Biomechanical determinants of elite rowing technique and performance.

In rowing, the parameters of injury, performance, and technique are all interrelated and in dynamic equilibrium. Whilst rowing requires extreme physical strength and endurance, a high level of skill and technique is essential to enable an effective transfer of power through the rowing sequence. This study aimed to determine discrete aspects of rowing technique, which strongly influence foot force production and asymmetries at the foot-stretchers, as these are biomechanical parameters often associated with performance and injury risk. Twenty elite female rowers performed an incremental rowing test on an instrumented rowing ergometer, which measured force at the handle and foot-stretchers, while three-dimensional kinematic recordings of the ankle, knee, hip, and lumbar-pelvic joints were made. Multiple regression analyses identified hip kinematics as a key predictor of foot force output (R(2) = 0.48), whereas knee and lumbar-pelvic kinematics were the main determinants in optimizing the horizontal foot force component (R(2) = .41). Bilateral asymmetries of the foot-stretchers were also seen to significantly influence lumbar-pelvic kinematics (R(2) = 0.43) and pelvic twisting (R(2) = 0.32) during the rowing stroke. These results provide biomechanical evidence toward aspects of technique that can be modified to optimize force output and performance, which can be of direct benefit to coaches and athletes.

Posterior mini-incision total hip arthroplasty controls the extent of post-operative formation of heterotopic ossification.

Heterotopic ossification (HO) is the formation of bone at extra-skeletal sites. Reported rates of HO after hip arthroplasty range from 8 to 90 %; however, it is only severe cases that cause problems clinically, such as joint stiffness. The effects of surgical-related controllable intra-operative risk factors for the formation of HO were investigated. Data examined included gender, age of patient, fat depth, length of operation, incision length, prosthetic fixation method, the use of pulsed lavage and canal brush, and component size and material. All cases were performed by the same surgeon using the posterior approach. A total of 510 cases of hip arthroplasty were included, with an overall rate of HO of 10.2 %. Longer-lasting operations resulted in higher grades of HO (p = 0.047). Incisions >10 cm resulted in more widespread HO formation (p = 0.021). No further correlations were seen between HO formation and fat depth, blood loss, instrumentation, fixation methods or prosthesis material. The mini-incision approach is comparable to the standard approach in the aetiology of HO formation, and whilst the rate of HO may not be controllable, a posterior mini-incision approach can limit its extent.

No difference in patellar tracking between symmetrical and asymmetrical femoral component designs in TKA.

PURPOSE: Poor knee extension function after total knee arthroplasty (TKA) is associated with factors including articular geometry and alignment. Femoral trochlear geometry has evolved from symmetrical to become more prominent proximal-laterally, with the groove aligned proximal-lateral to distal-medial. This study in vitro tested the hypothesis that a modern asymmetrical prosthesis would restore patellar tracking and stability to more natural behaviour than an older symmetrical prosthesis. METHODS: Six knees had their patellar tracking measured optically during active knee extension. Medial-lateral force versus displacement stability was measured at fixed angles of knee flexion. The measurements were repeated after inserting each of the symmetrical and asymmetrical TKAs. RESULTS: Significant differences of patellar lateral displacement stability, compared to normal, were not found at any angle of knee flexion. The patella tracked medial-laterally within 2.5 mm of the natural path with both TKAs. However, for both TKAs near knee extension, the patella was tilted laterally by approximately 6° and was also flexed approximately 8° more than in the natural knee. CONCLUSION: The hypothesis was not supported: The more anatomical component design did not provide more anatomical patellar kinematics and stability.

Case suitability for definitive through knee amputation following lower extremity blast trauma: analysis of 146 combat casualties, 2008-2010.

INTRODUCTION: Analysis of recent UK Armed Forces combat casualty data has highlighted a significant number of through joint traumatic amputations (TAs), most commonly through knee (through knee amputations (TKAs)). Previously, a consensus statement on lower limb amputation from the UK Defence Medical Services reported better outcomes in some patients with TKAs when compared with those with above knee amputations. This study sought to define the proportion of recent combat casualties sustaining severe lower extremity trauma with acute osseous and soft tissue injury anatomy amenable to definitive TKA. METHODS: The UK Joint Theatre Trauma Registry and post mortem CT (PM-CT) databases were used to identify all UK Armed Forces personnel (survivors and fatalities) sustaining a major extremity TA (through/proximal to wrist or ankle joint) between August 2008 and August 2010. Through knee and all below knee TAs were grouped as 'potential TKAs' (pTKAs), that is, possible candidates for definitive TKA. RESULTS: 146 Cases (75 survivors and 71 fatalities) sustaining 271 TAs (130 in survivors, 141 in fatalities) were identified. The through-joint TA rate was 47/271 (17.3%); 34/47 through-joint injuries (72.3%) were TKAs. Overall, 63/130 TAs in survivors and 66/140 TAs in fatalities merited analysis as the pTKA group. Detailed anatomical data on pre-debridement osseous and soft tissue injury levels were only consistently available for fatalities through PM-CT findings. Further analysis of the soft tissue injury profile revealed that a definitive TKA in the pTKA group (all BKAs as well as TKAs) would have been proximal to the zone of injury (ZOI) in only 3/66 cases. CONCLUSIONS: Traumatic TKAs following explosive blast are more common than previously reported. The majority of lower limb TAs are skeletally amenable to a definitive TKA. Maximising residual stump length carries the risks of definitive level amputation within the original ZOI but this study demonstrates that the proximal extent of the soft tissue injury may frequently make this unavoidable. Further work is required to determine the relative merits of definitive below, through and above knee amputations in the short, medium and long term to ensure survivors are subject to minimal complications while maintaining capacity to achieve optimal functional outcomes.

Blast-mediated traumatic amputation: evidence for a revised, multiple injury mechanism theory.

INTRODUCTION: The accepted mechanism of blast-mediated traumatic amputation (TA) is blast wave induced fracture followed by limb avulsion from the blast wind, generating a transosseous amputation. Blast-mediated through-joint TAs were considered extremely rare with published prevalence <2%. Previous studies have also suggested that TA is frequently associated with fatal primary blast lung injury (PBLI). However, recent evidence suggests that the mechanism of TA and the link with fatal primary blast exposure merit review. METHODS: A trauma registry (UK Joint Theatre Trauma Registry) and postmortem CT (PM-CT) database were used to identify casualties (survivors and deaths) sustaining a blast-mediated TA in the 2 years from August 2008. TA metrics and associated significant injuries were recorded. Detailed anatomical data on extremity predebridement osseous and soft tissue injuries were only consistently available for deaths through comprehensive PM-CT imaging. RESULTS: 146 cases (75 survivors and 71 deaths) sustaining 271 TAs (130 in survivors and 141 in deaths) were identified. The lower limb was most commonly affected (117/130 in survivors, 123/141 in deaths). The overall through-joint TA rate was 47/271 (17.3%) and 34/47 through-joint injuries (72.3%) were through knee. More detailed anatomical analysis facilitated by PM-CT imaging revealed only 9/34 through-joint TAs had a contiguous fracture (ie, intra-articular involving the joint through which TA occurred), 18/34 had no fracture and 7/34 had a non-contiguous (ie, remote from the level of TA) fracture. No relationship between PBLI and TA was evident. CONCLUSIONS: The previously reported link between TA and PBLI was not present, calling into question the significance of primary blast injury in causation of blast mediated TAs. Furthermore, the accepted mechanism of injury can't account for the significant number of through-joint TAs. The high rate of through-joint TAs with either no associated fracture or a non-contiguous fracture (74%) is supportive of pure flail as a mechanism for blast-mediated TA.

Understanding the burden of injury in children from conflict: an analysis of radiological imaging from a Role 3 hospital in Afghanistan in 2011.

INTRODUCTION: There is a need for quality medical care for children injured in conflict, but a description of injuries and injury burden from blast and ballistic mechanisms is lacking. The radiology records of children imaged during the war in Afghanistan represent a valuable source of information about the patterns of paediatric conflict injuries. METHODS: The UK military radiological database was searched for all paediatric presentations to Camp Bastion during 2011. Reports and original images were reviewed to determine location and severity of injuries sustained. Additional information was obtained from imaging request forms and the Joint Theatre Trauma Register, a database of those treated at UK medical facilities in Iraq and Afghanistan. RESULTS: Radiology was available for 219 children. 71% underwent CT scanning. 46% suffered blast injury, 22% gunshot wounds (GSWs), and 32% disease and non-battle injuries (DNBIs). 3% had penetrating head injury, 11% penetrating abdominal trauma and 8% lower limb amputation, rates far exceeding those found in civilian practice. Compared with those with DNBI, those with blast or GSW were more likely to have serious (Abbreviated Injury Score, AIS, ≥3) injuries (median no. AIS ≥3 injuries were 1 for blast, 1 for GSW and 0 for DNBI, p<0.05) and children exposed to blast were more likely to have multiple body regions with serious injuries (OR for multiple AIS ≥3 injuries for blast vs DNBI=5.811 CI [1.877 to 17.993], p<0.05). CONCLUSIONS: Paediatric conflict injuries are severe, and clinicians used only to civilian practice may be unprepared for the nature and severity of injuries inflicted on children in conflict. Whole-body CT for those with conflict-related injuries, especially blast, is hugely valuable. We recommend that CT is used for paediatric assessment in blast and ballistic incidents and that national imaging guidelines amend the threshold for doing so.

Relationship between combat-related traumatic injury and ultrashort term heart rate variability in a UK military cohort: findings from the ADVANCE study.

INTRODUCTION: Combat-related traumatic injury (CRTI) has been linked to an increased cardiovascular disease (CVD) risk. The long-term impact of CRTI on heart rate variability (HRV)-a robust CVD risk marker-has not been explored. This study investigated the relationship between CRTI, the mechanism of injury and injury severity on HRV. METHODS: This was an analysis of baseline data from the ArmeD SerVices TrAuma and RehabilitatioN OutComE (ADVANCE) prospective cohort study. The sample consisted of UK servicemen with CRTI sustained during deployment (Afghanistan, 2003-2014) and an uninjured comparison group who were frequency matched to the injured group based on age, rank, deployment period and role in theatre. Root mean square of successive differences (RMSSD) was measured as a measure of ultrashort term HRV via <16 s continuous recording of the femoral arterial pulse waveform signal (Vicorder). Other measures included injury severity (New Injury Severity Scores (NISS)) and injury mechanism. RESULTS: Overall, 862 participants aged 33.9±5.4 years were included, of whom 428 (49.6%) were injured and 434 (50.3%) were uninjured. The mean time from injury/deployment to assessment was 7.91±2.05 years. The median (IQR) NISS for those injured was 12 (6-27) with blast being the predominant injury mechanism (76.8%). The median (IQR) RMSSD was significantly lower in the injured versus the uninjured (39.47 ms (27.77-59.77) vs 46.22 ms (31.14-67.84), p<0.001). Using multiple linear regression (adjusting for age, rank, ethnicity and time from injury), geometric mean ratio (GMR) was reported. CRTI was associated with a 13% lower RMSSD versus the uninjured group (GMR 0.87, 95% CI 0.80-0.94, p<0.001). A higher injury severity (NISS ≥25) (GMR 0.78, 95% CI 0.69-0.89, p<0.001) and blast injury (GMR 0.86, 95% CI 0.79-0.93, p<0.001) were also independently associated with lower RMSSD. CONCLUSION: These results suggest an inverse association between CRTI, higher severity and blast injury with HRV. Longitudinal studies and examination of potential mediating factors in this CRTI-HRV relationship are needed.

Implementation of standardised surveillance for Clostridium difficile infections in Australia: initial report from the Victorian Healthcare Associated Infection Surveillance System.

Detection of a hypervirulent strain of Clostridium difficile in Victoria led to commencement of targeted surveillance for C. difficile infection in 2010. Cases were reported through the Victorian Healthcare Associated Infection Surveillance System. Between 1 October 2010 and 31 March 2011, 477 cases of C. difficile infection were identified; 11 (2.3%) secondary to a hypervirulent strain. Three hundred and seventy (1.7 per 10,000 occupied bed days) were healthcare associated. Data reflect successful implementation of continuous surveillance for C. difficile infection. With hypervirulent C. difficile infection now reported in other Australian states, development of a national data repository for C. difficile infection is necessary.

Knee and hip joint forces--sensitivity to the degrees of freedom classification at the knee.

Previous research has demonstrated that the number of degrees of freedom (DOF) modelled at a given joint affects the antagonistic muscle activity predicted by inverse dynamics optimization techniques. This higher level of muscle activity in turn results in greater joint contact forces. For instance, modelling the knee as a 3 DOF joint has been shown to result in higher hip and knee joint forces commensurate with a higher level of muscular activity than when the knee is modelled with 1 DOF. In this study, a previously described musculoskeletal model of the lower limb was used to evaluate the sensitivity of the knee and hip joint contact forces to the DOF at the knee during vertical jumping in both a 1 and a 3 DOF knee model. The 3 DOF knee was found to predict higher tibiofemoral and hip joint contact forces and lower patellofemoral joint contact forces. The magnitude of the difference in hip contact force was at least as significant as that found in previous research exploring the effect of subject-specific hip geometry on hip contact force. This study therefore demonstrates a key sensitivity of knee and hip joint contact force calculations to the DOF at the knee. Finally, it is argued that the results of this study highlight an important physiological question with practical implications for the loading of the structures of the knee; that is, the relative interaction of muscular, ligamentous, and articular structures in creating moment equilibrium at the knee.

Predicting the lumbosacral joint centre location from palpable anatomical landmarks.

The kinematics of the lumbar spine have previously been described by considering the bearing of the pelvis and lower back. However earlier studies have not described an intersegmental angle measured about a single point; which is necessary for investigation into movement, posture and balance, and lower back pain and injury. This study used computed tomography (CT) scans of 16 pelves to determine the location of palpable bony landmarks, and the junction of the fifth lumbar and first sacral vertebrae within a pelvis axis system. Data were used to derive equations which express the three-dimensional location of the lumbosacral joint centre as an offset from palpable surface landmarks. The magnitude of X, Y, Z offsets was controlled using individual pelvic geometry, and robustness and repeatability of the method was assessed. Regression equations provided the location of the lumbosacral junction to within 8.2mm (+/- 3.4mm) of its true coordinate. Leave-one-out analyses calculated equation coefficients using 15 of the original pelves, with the 16th acting as a control; average errors increased by 6.7 per cent (+/- 0.1 percent). To the authors' knowledge the current method is the most accurate non-invasive means of locating the lumbosacral junction and may be useful for constructing biomechanical models.

Lower-extremity musculoskeletal geometry affects the calculation of patellofemoral forces in vertical jumping and weightlifting.

The calculation of the patellofemoral joint contact force using three-dimensional (3D) modelling techniques requires a description of the musculoskeletal geometry of the lower limb. In this study, the influence of the complexity of the muscle model was studied by considering two different muscle models, the Delp and Horsman models. Both models were used to calculate the patellofemoral force during standing, vertical jumping, and Olympic-style weightlifting. The patellofemoral forces predicted by the Horsman model were markedly lower than those predicted by the Delp model in all activities and represented more realistic values when compared with previous work. This was found to be a result of a lower level of redundancy in the Delp model, which forced a higher level of muscular activation in order to allow a viable solution. The higher level of complexity in the Horsman model resulted in a greater degree of redundancy and consequently lower activation and patellofemoral forces. The results of this work demonstrate that a well-posed muscle model must have an adequate degree of complexity to create a sufficient independence, variability, and number of moment arms in order to ensure adequate redundancy of the force-sharing problem such that muscle forces are not overstated.

Real-Time Interface Algorithm for Ankle Kinematics and Stiffness From Electromyographic Signals.

Shortcomings in capabilities of below-knee (transtibial) prostheses, compared to their biological counterparts, still cause medical complications and functional deficit to millions of amputees around the world. Although active (powered actuation) transtibial prostheses have the potential to bridge these gaps, the current control solutions limit their efficacy. Here we describe the development of a novel interface for two degrees-of-freedom position and stiffness control for below-knee amputees. The developed algorithm for the interface relies entirely on muscle electrical signals from the lower leg. The algorithm was tested for voluntary position and stiffness control in eight able-bodied and two transtibial amputees and for voluntary stiffness control with foot position estimation while walking in eight able-bodied and one transtibial amputee. The results of the voluntary control experiment demonstrated a promising target reaching success rate, higher for amputees compared to the able-bodied individuals (82.5% and 72.5% compared to 72.5% and 68.1% for the position and position and stiffness matching tasks respectively). Further, the algorithm could provide the means to control four stiffness levels during walking in both amputee and able-bodied individuals while providing estimates of foot kinematics (gait cycle cross-correlation >75% for the sagittal and >90% for the frontal plane and gait cycle root mean square error <7.5° in sagittal and <3° in frontal plane for able-bodied and amputee individuals across three walking speeds). The results from the two experiments demonstrate the feasibility of using this novel algorithm for online control of multiple degrees of freedom and of their stiffness in lower limb prostheses.

A biomechanical basis for tears of the human acetabular labrum.

OBJECTIVE: Acetabular labral tears predominantly affect young patients and are a source of hip pain in the athlete. Four causes of the initiation of labral tears have been proposed; trauma, hypolaxity of the anterior capsule, dysplasia and bony impingement. A further cause could be reduced biomechanical properties in the area most susceptible to tears. However, no work has defined these properties. DESIGN: 32 compressive and 32 tensile test samples were harvested from fresh-frozen cadaveric acetabula. The labrum was divided into eight areas to allow comparison around its circumference. Semiconfined compressive testing and tensile testing were performed at a displacement rate of 10 mm/min in a controlled environment of 100% humidity at 37 (SD 1) degrees C. SETTING: Cadaveric study. RESULTS: The mean compressive stiffness was 31.75 (SD 16.7) MPa, and the mean tensile elastic modulus was 24.7 (SD 10.8) MPa. The anterosuperior region had a significantly lower compressive elastic modulus than either of the posterior quadrants (p<0.05) and a significantly lower tensile modulus to the anterioinferior area (p<0.05). CONCLUSIONS: The biomechanical properties in the anterosuperior region may be a contributing factor to the initiation of labral tears.

A numerical tool for the reconstruction of the physiological kinematics of the glenohumeral joint.

The aim of this study was to develop and test a robust approach to apply a joint coordinate system (JCS) to imaging data sets of the glenohumeral joint and to reconstruct the kinematics with six degrees of freedom (6DOF) in order to investigate shoulder pathologies related to instability. Visible human data were used to reconstruct bony morphology. Landmarks were used to define axes for body-fixed Cartesian coordinate frames on the humerus and scapula. These were applied to a three-cylinder open-chain JCS upon which the humeral 6DOF motions relative to the scapula were implemented. Software was written that applies 6DOF input variables to rotate and translate the nodes of the surface geometry of the humerus relative to the scapula in a global coordinate frame. The instantaneous relative position and orientation of the humerus for a given set of variables were thus reconstructed on the bone models for graphical display. This tool can be used for graphical animation of shoulder kinematics, demonstrating clinical assessments, and allowing further analysis of the function of tissues within the joint.