Conventional Pins Research Articles

Intramedullary implant stability affects patterns of fracture healing in mice with morphologically different bone phenotypes

Almost all prior mouse fracture healing models have used needles or K-wires for fixation, unwittingly providing inadequate mechanical stability during the healing process. Our contention is that the reported outcomes have predominantly reflected this instability, rather than the impact of diverse biological conditions, pharmacologic interventions, exogenous growth factors, or genetic considerations. This important issue becomes obvious upon a critical review of the literature. Therefore, the primary aim of this study was to demonstrate the significance of mouse-specific implants designed to provide both axial and torsional stability (Screw and IM Nail) compared to conventional pins (Needle and K-wires), even when used in mice with differently sized marrow canals and diverse genetic backgrounds. B6 (large medullary canal), DBA, and C3H (smaller medullary canals) mice were employed, all of which have different bone morphologies. Closed femoral fractures were created and stabilized with intramedullary implants that provide different mechanical conditions during the healing process. The most important finding of this study was that appropriately designed mouse-specific implants, providing both axial and torsional stability, had the greatest influence on bone healing outcomes regardless of the different bone morphologies encountered. For instance, unstable implants in the B6 strain (largest medullary canal) resulted in significantly greater callus, with a fracture region mainly comprising trabecular bone along with the presence of cartilage 28 days after surgery. The DBA and C3H strains (with smaller medullary canals) instead formed significantly less callus, and only had a small amount of intracortical trabeculation remaining. Moreover, with more stable fracture fixation a higher BV/TV was observed and cortices were largely restored to their original dimensions and structure, indicating an accelerated healing and remodeling process. These observations reveal that the diaphyseal cortical thickness, influenced by the genetic background of each strain, played a pivotal role in determining the amount of bone formation in response to the fracture. These findings are highly important, indicating the rate and type of tissue formed is a direct result of mechanical instability, and this most likely would mask the true contribution of the tested genes, genetic backgrounds, or various therapeutic agents administered during the bone healing process.

A handheld confocal microendoscope compatible with laparoscopy for histology in situ

Large-area in situ real-time imaging with cellular resolution is important in small animal imaging and clinical diagnoses. Laparoscopy is a commonly used technical tool in minimally invasive surgeries. However, laparoscopies cannot achieve cellular resolution. Here we propose a handheld rigid confocal microendoscope with a high numerical aperture, large imaging field of view, and high-resolution laparoscopic confocal objective lens that provides cellular structural information equivalent to that provided by pathological biopsies in real time. With a field-of-view diameter of approximately 540 μm and a lateral resolution of 1.95 μm, which are sufficient for distinguishing cells, the system is both handheld and compatible with conventional laparoscopic trocar pins. Through ex vivo/in situ imaging experiments on various organs, including rat livers, kidneys, and spleens, the potential of this system in clinical applications is demonstrated.

A novel 3.3 kV 4H-SiC trench PiN with enhanced conductance modulation effect

A novel 3.3 kV rated 4H-SiC trench PiN (T-PiN) structure, which features a trench P+ layer, is proposed and experimentally demonstrated. For the T-PiNs, dry etch onto the N-drift layer is added to the manufacturing process of conventional PiNs (Con-PiNs) before the Al ion implantation step. As the experimental results show, the forward current of the T-PiN diode with an active area of 5 mm × 5 mm has been improved by 32.3% at a voltage of 4 V. Apart from a slight sacrifice in breakdown voltage, the T-PiN is identical to the Con-PiN with regard to other static and surge current capabilities and dynamic characteristics. This superior forward conduction ability of the T-PiNs is a result of enhanced anode carrier injection caused by an enhanced conductance modulation effect and a larger anode carrier injection area. An enhanced conductance modulation effect model was also set up to quantify the increase in the proportion of current density in the T-PiN.

Evaluation of Active Heat Sinks Design under Forced Convection-Effect of Geometric and Boundary Parameters.

This study shows the performance of heat sinks (HS) with different designs under forced convection, varying geometric and boundary parameters, via computational fluid dynamics simulations. Initially, a complete and detailed analysis of the thermal performance of various conventional HS designs was taken. Afterwards, HS designs were modified following some additive manufacturing approaches. The HS performance was compared by measuring their temperatures and pressure drop after 15 s. Smaller diameters/thicknesses and larger fins/pins spacing provided better results. For fins HS, the use of radial fins, with an inverted trapezoidal shape and with larger holes was advantageous. Regarding pins HS, the best option contemplated circular pins in combination with frontal holes in their structure. Additionally, lattice HS, only possible to be produced by additive manufacturing, was also studied. Lower temperatures were obtained with a hexagon unit cell. Lastly, a comparison between the best HS in each category showed a lower thermal resistance for lattice HS. Despite the increase of at least 38% in pressure drop, a consequence of its frontal area, the temperature was 26% and 56% lower when compared to conventional pins and fins HS, respectively, and 9% and 28% lower when compared to the best pins and best fins of this study.

Heat Transfer and Pressure Drop Measurements in a High Aspect Ratio Channel With Circular Pins and Strip Fins

Abstract This paper focuses on the measurements of heat transfer enhancement and pressure drop of different pin or fin configurations in a high aspect ratio (AR = 9.57/1.2) channel. Two different pin-fin shapes including circular pins and strip fins were studied. Different pin-fin spacings for circular pins (S/D = 2, 4) and strip fins (S/W = 8, 16) were investigated, respectively. In addition, the thickness effect of the strip fin was included in this study. The regionally averaged heat transfer measurement method was used to acquire the heat transfer coefficients on two opposite featured surfaces within the test channel. For each configuration, the tested Reynolds number was ranging from 20,000 to 80,000. The results indicate that the channel with circular pins has better heat transfer enhancement and higher pressure loss than their strip fins counterparts. However, the strip fins are considered better designs in terms of thermal performance. For the gas turbine designers aim at developing an improved internal cooling feature, this work demonstrates the great potential of the strip fins as a novel and effective cooling design compared with the conventional circular pins.

S16-05 SESSION 16: PLANNING/IMAGING – PART II REVOLUTIONISING DISTRACTION OSTEOGENESIS WITH THREE-DIMENSIONAL MRI AND A NOVEL 3D PRINTED TRANSFER DEVICE AND CARBON-PEEK BONE PINS.

Introduction: Despite the complex anatomy of the craniofacial skeleton, distraction osteogenesis for conditions such as hemifacial microsomia remains reliant upon two-dimensional planning using radiographs. Three-dimensional imaging with CT or MRI would enable improved accuracy in sequential bony movement resulting in more predictable outcomes. However, there are two key limitations (1) distraction devices result in considerable metallic artefact/signal void on CT and MRI respectively, and (2) the use of sequential ionising radiation (with CT and/or radiographs) is of concern in young children. The objectives of this study were to develop an artefact free mandibular distractor device to permit 3D MRI imaging for children with hemifacial microsomia. Methods: Utilising a standard mandibular distractor as the starting point, we engineered distractor bone pins from carbon-polyetheretherketone (PEEK) and a temporary ex-fix transfer device which was 3D printed in Translucent PolyJet Resin using Selective Laser Sintering. The carbon-PEEK pins were implanted into an animal model (sheep head) and the transfer device attached. Imaging was acquired on both 1.5T and 3T magnets (GE and Siemens). The imaging protocol included “Black Bone,” T1, T2, FLAIR, STIR and ZTE/PETRA imaging. Comparable CT imaging was acquired with bone algorithms. 3D volume rendering was completed using Fovia High Definition Volume Rendering® software. Results: The carbon-PEEK pins resulted in a signal void equivalent to the dimension of the pin (and in some areas a small amount of inadvertently introduced air), with no adjacent areas of MR-signal loss i.e. no artefact. The external transfer device was not visualised at all on MRI, thus resulting in no artefact. 3D MRI acquisition permitted both reconstruction of the imaging datasets in any plane, and volume rendering of the bone. No artefact was seen on CT imaging from the distractor or pins. Conclusion: A 3D printed transfer device could be utilised temporarily during the acquisition of imaging as an artefact-free method of 3D monitoring and planning. Utilising carbon-PEEK pins as an alternative to conventional stainless steel pins would also further minimise any associated imaging artefact. This has the potential to completely revolutionise how we perform distraction osteogenesis in the future by permitting three-dimensional planning, with subsequent improvement in patient outcome.

An intramedullary Echidna pin for fixation of comminuted clavicle fractures: a biomechanical study

BackgroundIntramedullary fixation of comminuted mid-shaft clavicle fractures has traditionally been employed with satisfactory clinical outcomes; however, pins with smooth surfaces may protrude from the bone and are prone to migration, while some threaded pins are difficult to remove post-operatively. The aim of this proof-of-concept study was to develop and evaluate the biomechanical strength of a novel intramedullary Echidna pin device designed to maintain fracture reduction, resist migration and facilitate ease of post-operative removal.MethodsThirty human clavicle specimens were harvested and fractured in a comminuted mid-shaft butterfly configuration. Each specimen was randomly allocated to three surgical repair groups including intramedullary fixation using the Echidna pin and Herbert Cannulated Bone Screw System, as well as plate fixation using bi-cortical locking screws. Using a biomechanical testing apparatus, construct bending and torsional stiffness were measured, as well as ultimate bending strength.ResultsThere was no significant difference in torsional stiffness and ultimate bending moment between the Echidna pin and Herbert screw repair constructs (p > 0.05); however, the Echidna pin construct demonstrated a significantly greater bending stiffness compared to that of the Herbert screw construct (mean difference 0.55 Nm/deg., p = 0.001). The plate construct demonstrated significantly greater torsional stiffness, bending stiffness and ultimate bending moment compared to those of the Herbert screw and Echidna pin (p < 0.05).ConclusionsAn intramedullary Echidna pin device was designed to stabilize comminuted fractures of the clavicle, maintain fracture compression and provide ease of removal post-operatively. Since the results suggest equivalent or superior torsional and bending stability in the Echidna pin compared to that of the Herbert screw, the Echidna pin concept may represent an alternative fixation device to conventional intramedullary screws, nails and pins; however, superior plating using bi-cortical locking screws provides substantially higher construct structural rigidity than intramedullary devices, and may therefore be useful in cases of osteoporotic bone, or where high fracture stability is required.

Biomechanical evaluation of novel ultrasound-activated bioresorbable pins for the treatment of osteochondral fractures compared to established methods.

Osteochondral injuries often lead to osteoarthritis of the affected joint. All established systems for refixation of osteochondral defects show certain disadvantages. To address the problem of reduced stability in resorbable implants, ultrasound-activated pins were developed. By ultrasound-activated melting of the tip of these implants, a more secure anchoring is assumed. The aim of the study was to investigate if ultrasound-activated pins can provide secure fixation of osteochondral fragments compared to screws and conventional resorbable pins. In a biomechanical laboratory setting, osteochondral fragments of the medial femoral condyle of sheep were refixated with ultrasound-activated pins [US fused poly(L-lactide-co-D,L-lactide) (PLDLLA) pins], polydioxanone (PDA) pins and conventional titanium screws. Anchoring forces of the different fixation methods were examined, registered and compared concerning shear force and tensile force. Concerning the pull out test, the US fused PLDLLA pins and titanium screws (~122 N and ~203 N) showed comparable good results, while the PDA pins showed significantly lower anchoring forces (~18 N). Examination of shear forces showed a significantly higher anchoring of the screws (~248 N) than the US fused PLDLLA pins (~218 N). Nevertheless, the US fused PLDLLA pins could significantly outperform the PDA pins (~68 N) concerning shear forces. The US fused PLDLLA pins demonstrated a comparable anchorage to the fixation with screws, but were free from the disadvantages of metal implants, i.e. the need for implant removal. The PDA pin application showed inferior biomechanical properties.

Magnesium’s Medical Mettle

Metal corrosion is usually a bad thing, but in some instances it can be beneficial, even therapeutic. For example, scientists have been developing biodegradable metal alloys that appear to promote healing when used as replacements for conventional noncorrosive metal pins and screws used to fix broken bones. A team of South Korean and Canadian researchers has now shown how magnesium screws laced with calcium and zinc—elements known to promote bone health—help heal small fractures in hands and wrists (Proc. Natl. Acad. Sci. USA 2016, DOI: 10.1073/pnas.1518238113). Using a variety of techniques, including fluorescence microscopy and energy-dispersive X-ray spectroscopy, the team tracked the water-driven degradation of screws inside patients at Ajou University Hospital for several months. A by-product of this degradation, magnesium hydroxide, spurs calcium phosphate formation near the screw. This activity, in turn, helps induce bone growth, says team member Hyung-Seop Han of the Korea Institute of Science & Technology.

Electroanalytical devices with pins and thread.

This work describes the adaptive use of conventional stainless steel pins-used in unmodified form or coated with carbon paste-as working, counter, and quasi-reference electrodes in electrochemical devices fabricated using cotton thread or embossed omniphobic R(F) paper to contain the electrolyte and sample. For some applications, these pin electrodes may be easier to modify and use than printed electrodes, and their position and orientation can be changed as needed. Electroanalytical devices capable of multiplex analysis (thread-based arrays or 96-well plates) were easily fabricated using pins as electrodes in either thread or omniphobic R(F) paper.

Complications after use of extracortical clamp device in combined and consecutive external and internal fixation of femoral bone

Introduction. Extracortical Clamp Device (ECD) is a tool that, unlike conventional wires and pins, does not perforate long bone cortex. Therefore, its use simplifies methods of combined and consequtive use of internal and external fixation, osteosynthesis in periprosthetic fractures and deformities. Purpose of the study - to compare the rate of complications and their structure depending on extracortical clamp device application and conventional transosseous elements in combined external fixation of femur. Materials and methods. We analyzed the complications arising in treatment of 66 patients with frames where ECD were used (group «ECD»). The results were compared with the results of treatment 29 patients, when utilizing combination of external and internal fixation, external fixation device included conventional transosseous elements only (group «W-P»). Results. In the group «ECD» inflammation of the soft tissues around fixing elements was identified in 14.8% of cases. In these patients complication arisen at 45.5% of the all used fixing elements; of them - 18.2% around ECD. In the group «W-P» pin-tract infection occurred in 29.2% cases. ECD breaking was in one case (3.7%) breaking of wires or pins in «W-P» group was diagnosed in 3 cases (13.6%). In the treatment of periprosthetic fractures and deformities with ECD soft tissues around fixing elements was in 16.7% of cases. In the treatment of similar fractures and deformities without prosthesis pin-tract infection were diagnosed in 21.5% cases. All of these complications did not affect the outcome. Other complications (neuropathy, contracture of the knee) were not depending on the application of ECD.

Comparison of conventional ROTEM® cups and pins to the ROTEM® cup and pin mini measuring cells (MiniCup)

Background. Thromboelastometry (ROTEM®) is a well-established measurement to guide perioperative coagulation management. Recently, an enhancement for low volume specimens using cup and pin mini measuring cells (MiniCup) was invented for scientific non-clinical use. The MiniCup measuring cells allow testing with half of the blood volume required to run a test as compared to the conventional ROTEM® cup and pin (150 μL vs. 300 μL per assay). Objectives. The aim of this prospective study was to compare ROTEM® results using conventional cups and pins to the results of the MiniCup measuring cells. Methods. Blood samples drawn during major pediatric surgery were analyzed using the conventional ROTEM® and the MiniCup system to compare parameters from the EXTEM, INTEM and FIBTEM assays. Results. Citrated blood samples (n = 120) from 70 pediatric patients were analyzed. Results of the MiniCup cells were considerably different than the conventional ROTEM® cups and pins measurements. The MiniCup results show less clot firmness and demonstrate higher variability in the parameters reflecting the kinetics of clot building. Conclusion. The MiniCup measuring cells may offer advantages in pediatric care or research facilities, but specific reference ranges need to be established first, and adequate reproducibility must be determined by further studies before clinical use can be recommended.

Refixation of Osteochondral Fractures by an Ultrasound-Activated Pin System - An Ovine In Vivo Examination Using CT and Scanning Electron Microscope.

Background: Osteochondral injuries, if not treated appropriately, often lead to severe osteoarthritis of the affected joint. Without refixation of the osteochondral fragment, human cartilage only repairs these defects imperfectly. All existing refixation systems for chondral defects have disadvantages, for instance bad MRI quality in the postoperative follow-up or low anchoring forces. To address the problem of reduced stability in resorbable implants, ultrasound-activated pins were developed. By ultrasound-activated melting of the tip of these implants a higher anchoring is assumed. Aim of the study was to investigate, if ultrasound-activated pins can provide a secure refixation of osteochondral fractures comparing to conventional screw and conventional, resorbable pin osteosynthesis. CT scans and scanning electron microscopy should proovegood refixation results with no further tissue damage by the melting of the ultrasound-activated pins in comparison to conventional osteosynthesis.Methods: Femoral osteochondral fragments in sheep were refixated with ultrasound-activated pins (SonicPin™), Ethipins® and screws (Asnis™). The quality of the refixated fragments was examined after three month of full weight bearing by CT scans and scanning electron microscopy of the cartilage surface.Results: The CT examination found almost no statistically significant difference in the quality of refixation between the three different implants used. Concerning the CT morphology, ultrasound-activated pins demonstrated at least the same quality in refixation of osteochondral fragments as conventional resorbable pins or screws. The scanning electron microscopy showed no major surface damage by the three implants, especially any postulated cartilage damage induced by the heat of the ultrasound-activated pin. The screws protruded above the cartilage surface, which may affect the opposingtibial surface.Conclusion: Using CT scans and scanning electron microscopy, the SonicPin™, the Ethipin® and screws were at least equivalent in refixation quality of osteochondral fragments.

High frequency circular translation pin-on-disk method for accelerated wear testing of ultrahigh molecular weight polyethylene as a bearing material in total hip arthroplasty

The temporal change of the direction of sliding relative to the ultrahigh molecular weight polyethylene (UHMWPE) component of prosthetic joints is known to be of crucial importance with respect to wear. One complete revolution of the resultant friction vector is commonly called a wear cycle. It was hypothesized that in order to accelerate the wear test, the cycle frequency may be substantially increased if the circumference of the slide track is reduced in proportion, and still the wear mechanisms remain realistic and no overheating takes place. This requires an additional slow motion mechanism with which the lubrication of the contact is maintained and wear particles are conveyed away from the contact. A three-station, dual motion high frequency circular translation pin-on-disk (HF-CTPOD) device with a relative cycle frequency of 25.3Hz and an average sliding velocity of 27.4mm/s was designed. The pins circularly translated at high frequency (1.0mm per cycle, 24.8Hz, clockwise), and the disks at low frequency (31.4mm per cycle, 0.5Hz, counter-clockwise). In a 22 million cycle (10 day) test, the wear rate of conventional gamma-sterilized UHMWPE pins against polished CoCr disks in diluted serum was 1.8mg per 24h, which was six times higher than that in the established 1Hz CTPOD device. The wear mechanisms were similar. Burnishing of the pin was the predominant feature. No overheating took place. With the dual motion HF-CTPOD method, the wear testing of UHMWPE as a bearing material in total hip arthroplasty can be substantially accelerated without concerns of the validity of the wear simulation.

Manufacture and characteristics of asymmetric membrane capsule shells with a novel wet phase inversion method

In order to overcome the difficulty in stripping and to improve the automaticity and efficiency, a novel method was developed to prepare asymmetric membrane capsule shells (AM-CSs). Soluble mold pins were used to replace conventional insoluble mold pins, and simplified process was designed. Investigated by scanning electron microscopy and dye test, the homemade AM-CSs had typical asymmetric structure, in situ pore formation ability and high water influx. The in vitro dissolution properties of AM-CSs and homogeneous membrane capsule shells (HM-CSs) were compared. The release behavior of Metoprolol Tartrate and Nimodipine from the AM-CSs was mainly dominated by osmosis, while no drug could release from HM-CSs. The novel wet phase inversion method had significant advantages as well as potential value to be used in pharmaceutical research and application.

Forced convective heat transfer enhancement with perforated pin fins

Increasing miniaturization of high speed multi-functional electronics demands ever more stringent thermal management. The present work investigates experimentally and numerically the use of staggered perforated pin fins to enhance the rate of heat transfer in these devices. In particular, the effects of the number of perforations and the diameter of perforation on each pin are studied. The results show that the Nusselt number for the perforated pins is 45 % higher than that for the conventional solid pins and it increases with the number of perforation. Pressure drop with perforated pins is also reduced by 18 % when compared with that for solid pins. Perforations produce recirculations in the x–y as well as the x–z planes downstream of the pins which effectively increase convective heat transfer. However, thermal dissipation decreases significantly when the ratio of pin diameter to perforation diameter exceeds 0.375. This is due to both a reduction in the number of perforation per pin and the decrease in the axial heat conduction along the pin.

Physics study of deep-burning of spent fuel transuranics using commercial LWR cores

This paper describes a physics study of the utilization and destruction of the transuranic (TRU) nuclides contained in spent fuel through a high burnup irradiation (Deep Burn) in commercial light water reactors (LWR). The TRU nuclides are contained in the Fully Ceramic Micro-encapsulated (FCM) fuel, comprising of TRISO particles dispersed in a matrix of silicon carbide and manufactured in fuel pellets and fuel pins. This study is performed by using the traditional two-step core design procedure, which consists of fuel assembly calculations and core analysis. The main focus is on the core physics characteristics including safety-related parameters. The target reference core is the YongGwang unit 3, cycle 6 reload core. New fuel assemblies consisting of the conventional UO2 pins and new FCM TRU fuel pins are charged into the cores from cycle 6 to an equilibrium cycle. The results show that the reload cores can be designed to achieve the deep-burning (∼60% burnup) of TRU without adverse changes to the safety-related parameters and the core performance parameters. The equilibrium core has TRU self-recycling capabilities, being able to “deep burn” as much TRU nuclides as it generates.

A 12-Gb/s Non-Contact Interface With Coupled Transmission Lines

The expanding capacity of today's memory cards and increasing speed of processors have created demands for high data rate interfaces between memory cards and processors. Compared to conventional contact pins, wireless interfaces have received tremendous interest for reasons of more convenience, higher reliability, and higher data rate. Two major types of near-field wireless communication techniques using capacitive coupling and inductive coupling channels have been investigated. Tens of Gb/s/ch is achieved using both methods with a communication distance of tens of microns in TCI (thru-chip-interface) applications [1–2]. However, when the communication distance denters the mm range in such applications as non-contact memory cards, the sizes of capacitors or inductors must be up scaled to detect enough electrical flux or magnetic flux, whose magnitude decay as 1/dn (n>1). As a result, the self-resonance frequency f SR is reduced significantly, which becomes the dominant limiting factor for the achievable data rate, since the maximum data rate is usually chosen as 1/2 or 1/3 of f SR in order to avoid signal peaking [3]. Although multi-channel solutions are viable to increase the total data rate, complex systems are required to address the skew issues in synchronization, and low area efficiency is resulted to reduce crosstalk interferences as shown in Fig. 28.3.1.

Refixation of osteochondral fractures by ultrasound-activated, resorbable pins

ObjectivesOsteochondral injuries, if not treated adequately, often lead to severe osteoarthritis. Possible treatment options include refixation of the fragment or replacement therapies such as Pridie drilling, microfracture or osteochondral grafts, all of which have certain disadvantages. Only refixation of the fragment can produce a smooth and resilient joint surface. The aim of this study was the evaluation of an ultrasound-activated bioresorbable pin for the refixation of osteochondral fragments under physiological conditions.MethodsIn 16 Merino sheep, specific osteochondral fragments of the medial femoral condyle were produced and refixed with one of conventional bioresorbable pins, titanium screws or ultrasound-activated pins. Macro- and microscopic scoring was undertaken after three months. ResultsThe healing ratio with ultrasound-activated pins was higher than with conventional pins. No negative heat effect on cartilage has been shown.ConclusionAs the material is bioresorbable, no further surgery is required to remove the implant. MRI imaging is not compromised, as it is with implanted screws. The use of bioresorbable pins using ultrasound is a promising technology for the refixation of osteochondral fractures.

Wear measurement of highly cross-linked UHMWPE using a7Be tracer implantation technique

The very low wear rates achieved with the current highly cross-linked ultrahigh molecular weight polyethylenes (UHMWPE) used in joint prostheses have proven to be difficult to measure accurately by gravimetry. Tracer methods are therefore being explored. The purpose of this study was to perform a proof-of-concept experiment on the use of the radioactive tracer beryllium-7 ((7)Be) for the determination of in vitro wear in a highly cross-linked orthopedic UHMWPE. Three cross-linked and four conventional UHMWPE pins made from compression-molded GUR 1050, were activated with 10(9) to 10(10) (7)Be nuclei using a new implantation setup that produced a homogenous distribution of implanted nuclei up to 8.5 μm below the surface. The pins were tested for wear in a six-station pin-on-flat apparatus for up to 7.1 million cycles (178 km). A Germanium gamma detector was employed to determine activity loss of the UHMWPE pins at preset intervals during the wear test. The wear of the cross-linked UHMWPE pins was readily detected and estimated to be 17 ± 3 μg per million cycles. The conventional-to-cross-linked ratio of the wear rates was 13.1 ± 0.8, in the expected range for these materials. Oxidative degradation damage from implantation was negligible; however, a weak dependence of wear on implantation dose was observed limiting the number of radioactive tracer atoms that can be introduced. Future applications of this tracer technology may include the analysis of location-specific wear, such as loss of material in the post or backside of a tibial insert.