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Abstract Background ChatGPT has gained widespread attention for its ability to understand and provide human-like responses to inputs. However, few works have focused on its use in Orthopedics. This study assessed ChatGPT’s performance on the Orthopedic In-Service Training Exam (OITE) and evaluated its decision-making process to determine whether adoption as a resource in the field is practical. Methods ChatGPT’s performance on three OITE exams was evaluated through inputting multiple choice questions. Questions were classified by their orthopedic subject area. Yearly, OITE technical reports were used to gauge scores against resident physicians. ChatGPT’s rationales were compared with testmaker explanations using six different groups denoting answer accuracy and logic consistency. Variables were analyzed using contingency table construction and Chi-squared analyses. Results Of 635 questions, 360 were useable as inputs (56.7%). ChatGPT-3.5 scored 55.8%, 47.7%, and 54% for the years 2020, 2021, and 2022, respectively. Of 190 correct outputs, 179 provided a consistent logic (94.2%). Of 170 incorrect outputs, 133 provided an inconsistent logic (78.2%). Significant associations were found between test topic and correct answer (p = 0.011), and type of logic used and tested topic (p =

Introduction. Olecranon fractures are common injuries that require surgical intervention for optimal outcomes. Various fixation methods have been described in the literature, including the use of intramedullary proximal ulna screws in combination with tension band augmentation. Limited research has compared this hybrid technique to other established methods of fixation. This study compared complication and reoperation rates between multiple groups. Methods. A retrospective review was conducted on patients with olecranon fractures who underwent internal fixation at a level 1 trauma center between January 1st, 2013, and April 22nd, 2023. Data was collected using CPT codes, and patients were categorized into five groups based on the method of fixation received: no implant, tension band only, locking olecranon plate, intramedullary screw and tension band hybrid, and others. Variables such as patient demographics, Mayo fracture classification, open vs. closed injury, implant type, reoperation rates, and postoperative complications were recorded. Results. A total of 217 patients were included in the study. No difference was found with implant choice and reoperation rate (p=0.461). There was a significant difference found with reoperation and fracture type (p=0.027) and open fracture (p=0.002). Conclusion. The primary findings of this study indicate no significant difference in implant choice and reoperation rates among the various fixation methods used for olecranon fractures. These findings suggest that the hybrid fixation technique, utilizing intramedullary proximal ulna screws in combination with tension band augmentation, is a viable and comparable treatment option when evaluated against other well-documented methods of fixation. This study also reiterates that severity of initial injury is often the most important factor related to poorer outcomes. Further discussion and analysis of the data will provide a comprehensive understanding of implications and recommendations for olecranon fracture fixation.

Abstract Bayesian optimization (BO) has been leveraged for guiding autonomous and high-throughput experiments in materials science. However, few have evaluated the efficiency of BO across a broad range of experimental materials domains. In this work, we quantify the performance of BO with a collection of surrogate model and acquisition function pairs across five diverse experimental materials systems. By defining acceleration and enhancement metrics for materials optimization objectives, we find that surrogate models such as Gaussian Process (GP) with anisotropic kernels and Random Forest (RF) have comparable performance in BO, and both outperform the commonly used GP with isotropic kernels. GP with anisotropic kernels has demonstrated the most robustness, yet RF is a close alternative and warrants more consideration because it is free from distribution assumptions, has smaller time complexity, and requires less effort in initial hyperparameter selection. We also raise awareness about the benefits of using GP with anisotropic kernels in future materials optimization campaigns.

The primary objective was to evaluate performance of low concentration SDS decellularised porcine pulmonary roots in the right ventricular outflow tract of juvenile sheep. Secondary objectives were to explore the cellular population of the roots over time. Animals were monitored by echocardiography and roots explanted at 1, 3, 6 ( n = 4) and 12 months ( n = 8) for gross analysis. Explanted roots were subject to histological, immunohistochemical and quantitative calcium analysis ( n = 4 at 1, 3 and 12 months) and determination of material properties ( n = 4; 12 months). Cryopreserved ovine pulmonary root allografts ( n = 4) implanted for 12 months, and non-implanted cellular ovine roots were analysed for comparative purposes. Decellularised porcine pulmonary roots functioned well and were in very good condition with soft, thin and pliable leaflets. Morphometric analysis showed cellular population by 1 month. However, by 12 months the total number of cells was less than 50% of the total cells in non-implanted native ovine roots. Repopulation of the decellularised porcine tissues with stromal (α-SMA+; vimentin+) and progenitor cells (CD34+; CD271+) appeared to be orchestrated by macrophages (MAC 387+/ CD163 low and CD163+/MAC 387−). The calcium content of the decellularised porcine pulmonary root tissues increased over the 12-month period but remained low (except suture points) at 401 ppm (wet weight) or below. The material properties of the decellularised porcine pulmonary root wall were unchanged compared to pre-implantation. There were some changes in the leaflets but importantly, the porcine tissues did not become stiffer. The decellularised porcine pulmonary roots showed good functional performance in vivo and were repopulated with ovine cells of the appropriate phenotype in a process orchestrated by M2 macrophages, highlighting the importance of these cells in the constructive tissue remodelling of cardiac root tissues.

Decellularised heart valve roots offer a promising option for heart valve replacement in young patients, having the potential to remodel and repair. Replacement heart valves have to undergo billions of opening and closing cycles throughout the patient's lifetime. Therefore, understanding the effect of cyclic loading on decellularised heart valve roots is important prior to human implantation. The aim of this preliminary study was to investigate the influence of low concentration sodium dodecyl sulphate (SDS) decellularisation treatment on the in vitro real time mechanical fatigue of porcine aortic heart valve roots under physiological real time cyclic loading conditions. This required a specific real time in vitro method to be developed, since previous methods relied on accelerated testing, which is non-physiological, and not appropriate for valve replacement materials that exhibit time dependent characteristics. The effects of the real time fatigue on hydrodynamic function and mechanical properties of the heart valve roots were assessed. The mechanical fatigue of decellularised porcine aortic heart valve roots (n = 6) was assessed and compared to cellular porcine aortic heart valve roots (n = 6) in a modified Real time Wear Tester (RWT) at a physiological frequency and under cyclic pressure conditions for a maximum of 1.2 million cycles. Periodically, the heart valve roots were removed from the RWT to assess the influence of cyclic loading on valve competency (static leaflet closure). At the end of testing further hydrodynamic performance parameters were ascertained, along with determination of leaflet material properties. A real time mechanical fatigue assessment method was developed and applied; with two cellular and two decellularised porcine aortic leaflets in different heart valve roots showing tears in the belly region. The decellularised aortic heart valve roots exhibited comparative functionality to the cellular heart valve roots under in vitro static and pulsatile hydrodynamic conditions. However, the material properties of the decellularised aortic leaflets were significantly altered following cyclic fatigue assessment and showed increases in elastin and collagen phase slopes and ultimate tensile strength compared to the cellular porcine aortic leaflets in the circumferential direction. This preliminary study demonstrated that low concentration SDS decellularised porcine aortic heart valve roots can withstand physiological cyclic deformations up to 1.2 million cycles in a RWT whilst maintaining their overall hydrodynamic function and leaflet mechanical properties. This is the first full report of preclinical mechanical fatigue assessment of decellularised porcine aortic heart valve roots under physiological real time conditions.

Dynamic separation and direct edge loading of hip replacement bearings can be caused by many factors, including implant positioning, implant design, changes in device over time, surgical variations and patient variations. Such dynamic separation and direct edge loading can lead to increased wear. Different input kinematic conditions have been used for experimental hip simulator studies to produce clinically relevant elliptical contact wear paths between the bearings during gait. The aim of this study was to investigate the influence of input kinematics (two axes of rotation simulation conditions (without abduction/adduction) and three axes of rotation simulation conditions (with abduction/adduction and different loading profiles) and variations in component positioning (different levels of medial-lateral translational mismatch at standard and steep cup inclination angles) on the occurrence, severity of edge loading, dynamic separation and wear of size 36 mm ceramic-on-ceramic hip bearings on an electromechanical hip joint simulator. The results showed that, overall, either of the two axes or three axes input profiles were equally valid in providing a suitable preclinical testing method for assessing the occurrence and severity of edge loading and wear under edge loading conditions. In terms of component positioning, as cup inclination and medial-lateral translational mismatch increased, so did dynamic separation, axial load at the rim, severity of edge loading and wear.

A range of surgical techniques and osteochondral interventions have been developed for early stage chondral/osteochondral repair interventions in the knee however, methods for functional, pre-clinical assessment of these therapies are limited. In this study, a method for simulating physiological loading and motion in the porcine patellofemoral joint was developed using a 6-axis simulator. As an example of how the method can be used, the influence of surgical positioning of osteochondral allografts in the patella on cartilage wear, deformation and damage and graft stability was investigated in this porcine patellofemoral joint model. The functional performance of allografts implanted either optimally (flush with the cartilage surface) or 1 mm proud of the cartilage surface was compared to a positive control (stainless steel pin implanted 1 mm proud of the cartilage surface), a negative control (no intervention) and a defect model. Allografts implanted flush with the surrounding cartilage could restore the articulating surface of the patella resulting in low wear, damage and deformation of the opposing cartilage surface, similar to that of the negative control group. Implanting the graft proud of the patella surface resulted in cartilage lesions on the femoral trochlea (ICRS grade 2) and a cartilage volume difference of 2.0 ± 3.9 mm3; the positive controls resulted in more severe lesions, a higher volume difference (14.2 ± 7.4 mm3) which in some cases exposed subchondral bone (ICRS grade 4). Defects in the patella caused deformation of the opposing cartilage surface. All grafts implanted in the patella subsided over the duration of the study. This study demonstrated a method that can be used to evaluate osteochondral repair strategies in the patellofemoral joint applying physiological loading and motions.

Elephantorrhiza elephantina is a medicinally important plant whose roots are used to control gastrointestinal parasites in goats. The use of plant-based anthelmintics as potential alternatives to synthetic anthelmintics in controlling gastrointestinal worms in ruminants is a promising area of research. The study was carried out to ascertain the efficacy of E. elephantina in controlling goat trematodes. Standard procedures were used to quantify the phytochemicals in the water, ethanol and methanol root extracts of E. elephantina. The quantitative phytochemical analysis revealed that alkaloids (93.24 ± 1.68%), condensed tannins (450.52 ± 0.15 mg CE/g), flavonoids (803.93 ± 0.13 mg QE/g), phenols (476.11 ± 0.37 mg GAE/g) and saponins (83.28 ± 1.72%) were present in E. elephantina root extracts. Paramphistomum cervi adult worms recovered from the rumen of freshly slaughtered goats were used. In vitro screening of ethanol, methanol and water extracts of E. elephantina for potential anthelmintic activity against adult P. cervi worm motility showed time and dose-dependent significant effects. Ethanol extracts showed a highly significant (P

Attention has been given to the experience of individuals undergoing assisted reproductive techniques. However, only recent literature has focused on the spiritual journey triggered by such an event and highlighted the nurses and midwives’ roles in the assessment of the spiritual needs of those living with infertility. This study aimed to perform a psychometric test of the factor structure of the Portuguese version of the Spiritual Well-being Questionnaire in a sample of people undergoing assisted reproductive techniques. This descriptive cross-sectional study was conducted between September 2019 and June 2020 on a sample of 104 Portuguese adults attending fertility treatment. An online questionnaire was released on fertility-related websites. A confirmatory factor analysis was conducted on six hypothesized models of the instrument. The findings provided evidence of an adequate internal consistency of the instrument, and the validity and reliability of the oblique four-factor model was confirmed. Spiritual well-being had a significant association with the nature of infertility and a higher score was achieved by participants that perceived religion as very important. This study provides a validated tool for nurses and midwives to assess spiritual well-being and promote an integrated reproductive healthcare approach. Further longitudinal research with bigger samples would provide more evidence of the spiritual needs of people living with this condition.

A human cadaveric specimen-specific knee model with appropriate soft tissue constraints was developed to appropriately simulate the biomechanical environment in the human knee, in order to pre-clinically evaluate the biomechanical and tribological performance of soft tissue interventions. Four human cadaveric knees were studied in a natural knee simulator under force control conditions in the anterior posterior (AP) and tibial rotation (TR) axes, using virtual springs to replicate the function of soft tissues. The most appropriate spring constraints for each knee were determined by comparing the kinematic outputs in terms of AP displacement and TR angle of the human knee with all the soft tissues intact, to the same knee with all the soft tissues resected and replaced with virtual spring constraints (spring rate and free length/degree). The virtual spring conditions that showed the least difference in the AP displacement and TR angle outputs compared to the intact knee were considered to be the most appropriate spring conditions for each knee. The resulting AP displacement and TR angle profiles under the appropriate virtual spring conditions all showed similar shapes to the individual intact knee for each donor. This indicated that the application of the combination of virtual AP and TR springs with appropriate free lengths/degrees was successful in simulating the natural human knee soft tissue function. Each human knee joint had different kinematics as a result of variations in anatomy and soft tissue laxity. The most appropriate AP spring rate for the four human knees varied from 20 to 55 N/mm and the TR spring rate varied from 0.3 to 1.0 Nm/°. Consequently, the most appropriate spring condition for each knee was unique and required specific combinations of spring rate and free length/degree in each of the two axes.

Este artículo analiza el significado de la conspiración de 1805 de Gabriel Aguilar y José Manuel de Ubalde, la cual apuntaba a coronar un miembro de la elite indígena del Cusco como Emperador Inca de un Perú independiente. Aunque la conspiración falló, proporcionó un vínculo importante entre la insurgencia indígena generalizada de inicios de 1780’s, iniciada por José Gabreil Tupac Amaru, y el movimiento independista de base más amplia de 184-1815, el cual buscó unir a los criollos y a los habitantes indígenas del sur de Perú en un intento por un Perú independiente, con Cusco como su capital

A robust and stratified pre-clinical natural knee model, which has the capability to more appropriately simulate the biomechanical environment in vivo, will deliver more efficient and reliable assessment of soft tissue interventions before clinical studies. In order to simulate the biomechanical function of the natural knee without the natural ligaments in place, there is a requirement to develop appropriate spring constraints for the natural knee model. Therefore, this study was to investigate the effect of spring constraints on the function and output of the natural porcine knee model, and determine the spring constraint which most closely replicated the function of the natural ligaments. Two linear compression springs with stiffnesses of 9 N/mm (spring-9) and 20 N/mm (spring-20) were set at different free lengths in the anterior-posterior (A/P) axis in a natural knee simulator. The kinematic (A/P displacement) and tribological properties (shear force) output of the simulator were compared at different spring settings. The most appropriate spring setting was determined by comparing the A/P displacement and shear force output at different spring settings with those of the all ligaments model. Spring-9 with a free length of 4 mm showed the minimal difference (-0.03±0.68 mm) in A/P displacement output and spring-20 with a free length of 5 mm showed the minimal difference (-0.10±0.73 mm) in A/P displacement output compared to the all ligament control. There was no statistical difference between the two minimal differences either in A/P displacement or in shear force (paired t-test, p = 0.58, and p = 0.68 respectively) when both spring settings matched most closely to the A/P kinematics of the intact knee. This indicated that both conditions were appropriate spring constraints settings in the A/P direction for the natural porcine knee model.

In 1808 the political structures of the Hispanic world began to collapse as the fourth and fifth of Spain’s Bourbon monarchs —Charles IV (1788–1808) and Ferdinand VII (1808–1833)— abdicated in quick succession before going into a genteel imprisonment in France which lasted until 1814, thereby leaving the way clear for Napoleon Bonaparte’s brother, Joseph, to be crowned king of Spain in Madrid in June 1808. Despite the acquiescence of elements of the Spanish aristocracy and the enthusiasm for the change of dynasty among the country’s progressive afrancesados, almost immediately spontaneous popular resistance to what was in effect a Napoleonic takeover of the Spanish State became widespread throughout the country. It was coordinated by, first, the Junta Central, established in September 1808, and from January 1810 by a Council of Regency, installed in the Isla de León. This essay analyses the events in Spain from early-1808 that led to this outcome, and reactions to them in the viceroyalty of Peru, with particular reference to the application there of the Constitution of Cádiz of 1812, prior to the receipt in late-1814 of the news that the restored Ferdinand VII had abolished the liberal code in May of that year.En 1808 las estructuras políticas del mundo hispánico comenzaron a derrumbarse cuando el cuarto y quinto de los monarcas Borbones españoles —Carlos IV (1888–08) y Fernando VII (1808–33)— abdicaron sucesivamente y forzosamente se exiliaron en Francia hasta 1814, dejando el camino libre para el hermano de Napoleón Bonaparte, José, pudiera ser coronado rey de España en Madrid en junio de 1808. A pesar de la aquiescencia de la aristocracia española y el entusiasmo por el cambio de dinastía, entre los sectores afrancesados, la resistencia popular apareció muy pronto de manera espontánea, ya que se traba de una verdadera toma de posesión napoleónica del Estado español, que rápidamente se extendió por todo el país. Esta resistencia fue coordinada, primero, la Junta Central, creada en septiembre de 1808, y desde enero de 1810 por un Consejo de Regencia, instalado en la Isla de León. Este ensayo analiza los acontecimientos ocurridos en España desde principios del 1808, y las reacciones a los mismos en el virreinato del Perú, con especial referencia a la aplicación de la Constitución de Cádiz de 1812, y la recepción, a finales de 1814, de la noticia de que Fernando VII, restaurado en el trono, abolía la constitución en mayo de ese año.

Medical interventions for the treatment of spinal disc degeneration include total disc replacement and fusion devices. There are, however, concerns regarding the generation of wear particles by these devices, the majority of which are in the nanometre sized range with the potential to cause adverse biological effects in the surrounding tissues. The aims of this study were to develop an organ culture model of the porcine dura mater and to investigate the biological effects of CoCr nanoparticles in this model. A range of histological techniques were used to analyse the structure of the tissue in the organ culture. The biological effects of the CoCr wear particles and the subsequent structural changes were assessed using tissue viability assays, cytokine assays, histology, immunohistochemistry, and TEM imaging. The physiological structure of the dura mater remained unchanged during the seven days of in vitro culture. There was no significant loss of cell viability. After exposure of the organ culture to CoCr nanoparticles, there was significant loosening of the epithelial layer, as well as the underlying collagen matrix. TEM imaging confirmed these structural alterations. These structural alterations were attributed to the production of MMP-1, -3, -9, -13, and TIMP-1. ELISA analysis revealed that there was significant release of cytokines including IL-8, IL-6, TNF-α, ECP and also the matrix protein, tenascin-C. This study suggested that CoCr nanoparticles did not cause cytotoxicity in the dura mater but they caused significant alterations to its structural integrity that could lead to significant secondary effects due to nanoparticle penetration, such as inflammation to the local neural tissue.

The Spiritual Health And Life-Orientation Measure (SHALOM) is a 20-item instrument that assesses the quality of relationships of the respondent with self, others, the environment and/or a Transcendent Other. In the Transcendental domain, four of the five items had the words ‘God, ‘Divine’ and ‘Creator’ replaced by the word ‘Transcendent’ to make the survey more generic by removing any implied reference to any god or religion. Invitations to complete a web survey were sent to people who had published papers in spirituality, or belonged to associations for spirituality or religious studies, as well as the Australian Atheist Forum. 409 respondents from 14 geographic regions, completed the survey. Confirmatory factor analysis revealed that the modified, generic form of SHALOM showed acceptable model fit, comprising four clearly delineated domains of spiritual well-being. The paper analyses the results derived from using the modified, generic version and, in comparison with results of applications of the original survey instrument, concludes with discussion of the comparative utility of each of the versions of SHALOM. Further studies with more people are warranted, but, from evidence presented here, it looks like you can’t beat relating with God for spiritual well-being.

A previous study on university students reported that personal, communal, and environmental spiritual well-being contributed to happiness over and above personality but that relating with God did not. In this study, happiness was assessed using a modified Oxford Happiness Inventory. Personality scores were obtained using forms of Eysenck’s Personality Questionnaire. Four domains of spiritual well-being were determined using Fisher’s Spiritual Well-Being Questionnaire. Relationship with God was reflected by the Transcendental domain of spiritual well-being in this instrument. Studies with 466 university students from Australia, Northern Ireland, and England, 494 people attending churches in Ballarat, and 1002 secondary school students in Victoria showed that relating with God accounts for variance on happiness, over and above personality, and age.

The geometry of the articular components of the knee is an important factor in predicting joint mechanics in computational models. There are a number of uncertainties in the definition of the geometry of cartilage and meniscus, and evaluating the effects of these uncertainties is fundamental to understanding the level of reliability of the models. In this study, the sensitivity of knee mechanics to geometric uncertainties was investigated by comparing polynomial-based and image-based knee models and varying the size of meniscus. The results suggested that the geometric uncertainties in cartilage and meniscus resulting from the resolution of MRI and the accuracy of segmentation caused considerable effects on the predicted knee mechanics. Moreover, even if the mathematical geometric descriptors can be very close to the imaged-based articular surfaces, the detailed contact pressure distribution produced by the mathematical geometric descriptors was not the same as that of the image-based model. However, the trends predicted by the models based on mathematical geometric descriptors were similar to those of the imaged-based models.

The use of hip joint simulators to evaluate the tribological performance of total hip replacements is widely reported in the literature, however, in vitro simulation studies investigating the tribology of the natural hip joint are limited with heterogeneous methodologies reported. An in vitro simulation system for the complete natural hip joint, enabling the acetabulum and femoral head to be positioned with different orientations whilst maintaining the correct joint centre of rotation, was successfully developed for this study. The efficacy of the simulation system was assessed by testing complete, matched natural porcine hip joints and porcine hip hemiarthroplasty joints in a pendulum friction simulator. The results showed evidence of biphasic lubrication, with a non-linear increase in friction being observed in both groups. Lower overall mean friction factor values in the complete natural joint group that increased at a lower rate over time, suggest that the exudation of fluid and transition to solid phase lubrication occurred more slowly in the complete natural hip joint compared to the hip hemiarthroplasty joint. It is envisaged that this methodology will be used to investigate morphological risk factors for developing hip osteoarthritis, as well as the effectiveness of early interventional treatments for degenerative hip disease.

At our core, or coeur, we humans are spiritual beings. Spirituality can be viewed in a variety of ways from a traditional understanding of spirituality as an expression of religiosity, in search of the sacred, through to a humanistic view of spirituality devoid of religion. Health is also multi-faceted, with increasing evidence reporting the relationship of spirituality with physical, mental, emotional, social and vocational well-being. This paper presents spiritual health as a, if not THE, fundamental dimension of people’s overall health and well-being, permeating and integrating all the other dimensions of health. Spiritual health is a dynamic state of being, reflected in the quality of relationships that people have in up to four domains of spiritual well-being: Personal domain where a person intra-relates with self; Communal domain, with in-depth inter-personal relationships; Environmental domain, connecting with nature; Transcendental domain, relating to some-thing or some‑One beyond the human level. The Four Domains Model of Spiritual Health and Well‑Being embraces all extant world-views from the ardently religious to the atheistic rationalist.

The Four Domains Model of Spiritual Health and Well-Being was used as the theoretical base for the development of several spiritual well-being questionnaires, with progressive fine-tuning leading to the Spiritual Health And Life-Orientation Measure (SHALOM). SHALOM comprises 20 items with five items reflecting the quality of relationships of each person with themselves, other people, the environment and/or God, in the Personal, Communal, Environmental and Transcendental domains of spiritual well-being. SHALOM has undergone rigorous statistical testing in several languages. SHALOM has been used with school and university students, teachers, nurses, medical doctors, church-attenders, in industry and business settings, with abused women, troubled youth and alcoholics. SHALOM provides a unique way of assessing spiritual well-being as it compares each person’s ideals with their lived experiences, providing a measure of spiritual harmony or dissonance in each of the four domains.

Awareness of patients’ and healthy people’s spiritual well-being allows for care professionals to support individual spiritual concerns in a timely and appropriate manner, performing a whole-person approach to care. To date, there have been no validated measures of spiritual well-being for use with healthy or illness-affected Lithuanian people. This paper reports the translation and validation procedures of the Spiritual Well-Being Questionnaire, SHALOM, for its use with Lithuanian people regarding the self-assessment of spiritual health. A convenience sample of 171 hospitalized non-terminally ill oncology patients was interviewed face-to-face during a field-test of a Lithuanian version of SHALOM. Overall scale reliability of the SHALOM-Ideals section was 0.909, with overall scale reliability of the SHALOM-Lived Experience section being 0.888. Culturally relevant translation resulted in very good stability over time with a seven-day break between repeat application (Ideals section: Spearman-Brown coefficient was 0.927; Lived Experience section: Spearman-Brown coefficient was 0.942). The construct validity of the scale was determined using exploratory factor analysis. The research perspective on spirituality and spiritual well-being in Lithuania indicates the desirability for larger scale quantitative and qualitative studies with different populations applying cross-sectional and cross-cultural comparisons.

Tribology of hip joints is reviewed, covering a full spectrum from natural hip joints to total hip replacements, as well as tissue engineered articular cartilage. The importance of integrated tribological studies of contact mechanics, friction, wear and lubrication, as well as fully coupled with biological considerations, has been emphasized. The exact lubrication mechanism in natural hip joints is still not clear, although the unique biphasic characteristics of articular cartilage play an important role. Tribological studies of bearing surfaces for artificial hip joint replacements are important in developing and optimizing alternative material combinations to conventional polyethylene. Recently developed tissue engineered articular cartilage has been shown to be inadequate as far as the tribological property is concerned.