Introduction. Previous studies of CoCr alloy femoral components for total knee arthroplasty (TKA) have identified 3. rd. body abrasive wear, and apparent inflammatory cell induced corrosion (ICIC) [1] as potential damage mechanisms. The association between observed surface damage on the femoral condyle and metal ion release into the surrounding tissues is currently unclear. The purpose of this study was to investigate the damage on the bearing surface in TKA femoral components recovered at autopsy and compare the damage to the metal ion concentrations in the synovial fluid. Methods. 12 autopsy TKA CoCr femoral components were collected as part of a multi-institutional orthopedic implant retrieval program. The autopsy components included Depuy Synthes Sigma Mobile Bearing (n=1) and PFC (n=1), Stryker Triathlon (n=1) and Scorpio (n=3), and Zimmer Nexgen (n=4) and Natural Knee (n=2). Fluoro scans of all specimens prior to removal was carried out to assure no signs of osteolysis or aseptic loosening were present. Third-body abrasive wear of CoCr was evaluated using a semi-quantitative scoring method similar to the Hood method [2]. ICIC damage was reported as location of affected area and confirmed using a digital optical microscope with 4000X magnification. Synovial fluid was aspirated from the joint capsule prior to removal of the TKA device. The synovial fluid was spun at 1600 rpm for 20 minutes in a centrifuge with the cell pellet removed. The supernatant was analyzed in 1 mL quantities for ICP-MS (inductively coupled plasma mass spectrometry) by Huffman Hazen Laboratories. Data was expressed as ppb. Results. Mild to severe damage (Damage Score ≥ 2) was observed on 92% of the components in at least one quadrant, with no severe damage (Damage Score = 4) observed. ICIC damage was observed on three components in three different regions (the posterior lateral, anterior, and medial bearing surface). These observations were confirmed with digital optical microscopy, where we observed as interconnecting pits and indentations with a spiraling or trailing region, consistent with prior observation of ICIC in retrievals (Figure 1). Cobalt was detected in 7 cases, however the metal levels were not as high as levels observed in patients with a failed joint replacement (Table 1). There was no correlation between the metal ion concentration and the damage score on the CoCr femoral condyle. Discussion. This study documents the damage mechanics and associated metallic release into the synovial fluid of “well-functioning” TKA components retrieved at autopsy. It has been suggested that ICIC damage is actually damage from electrocautery during surgery. However, we observed ICIC damage on autopsy retrievals in which the use of electrocautery is unlikely. The damage mechanisms observed on the autopsy TKA components were similar but less severe compared to mechanisms observed in long-term TKA components from revision surgery [1]. More research is needed to better understand the metal release from CoCr femoral components and periprosthetic tissue reactions in TKA

We studied the mechanical and biochemical properties of articular cartilage from 22 osteoarthritic femoral heads obtained at operation and 97 femoral heads obtained at autopsy. Cartilage from the zenith and from the antero-inferior aspect of each head was tested both in tension and in compression. Water content, swelling ability and proteoglycan content were measured, the cartilage was examined histologically and the density of the underlying bone was assessed. Fifty-five of the autopsy specimens were defined as macroscopically normal because they exhibited no progressive fibrillation patterns on staining with Indian ink; but significant changes in water content, bone density and tensile strength related to age were seen in this group. In 20 pairs of femoral heads which were both macroscopically normal, we found, surprisingly, that cartilage from the left and right sides of the same patient was sometimes very different. Compared with the normal autopsy specimens the osteoarthritic specimens had a significantly increased swelling ability, a lower proteoglycan content and impaired mechanical properties, being both weaker in tension and softer in compression. Abnormal autopsy specimens had values intermediate between those of osteoarthritic and normal groups. Results from this abnormal group suggest that there is no primary loss of proteoglycan in early osteoarthritis

This study evaluates forty-four consecutive autopsy specimens of the senior author’s own patients in attempt to locate and measure periacetabular bone defects and correlate this information with their communication pathways with the joint space. The purpose of this study was to evaluate autopsy retrieved hemipelves of previously well-functioning total hip arthroplasties (THAs) with computed tomography (CT) to better understand patterns of osteolysis around modular uncemented acetabular components. Forty-four hemipelves containing titanium porous-coated modular acetabular components were retrieved at autopsy, imaged with CT, and analyzed to determine the location and volume of osteolytic lesions. The mean age of the patients at the time of surgery was seventy years. The mean time in situ for the implants was eight years. A total of forty-six osteolytic lesions were identified in twenty-eight of the forty-four cases (64%). Thirty-one of forty-six lesions (67%) had one or more apparent communications with the joint space. We identified four types of communication pathways between osteolytic lesions and the joint space: around the rim, through a central dome hole, in association with a screw or screw hole, or around a non-ingrown interface. The mean volume of lesions that had a clear communication pathway was significantly larger than those lesions that did not have a clear communication pathway (p=0.012). Thirteen of the fifteen lesions that did not have a clear communication with the joint space represented bone defects that had existed prior to total hip arthroplasty. Osteolysis was commonly observed at early time intervals around modular uncemented acetabular components. The communication with the joint space is important for developing osteolysis, as well as in the detection of true osteolytic lesions

INTRODUCTION. Adverse local tissue reactions (ALTR) and elevated serum metal ion levels secondary to fretting and corrosion at head-neck junctions in modular total hip arthroplasty (THA) designs have raised concern in recent years. Factors implicated in these processes include trunnion geometry, head-trunnion material couple, femoral head diameter, head length, force of head impaction at the time of surgery, and length of implantation. Our understanding of fretting and corrosion in vivo is based largely on the analysis of retrieved prostheses explanted for reasons related to clinical failure. Little is known about the natural history of head-neck tapers in well-functioning total hip replacements. We identified ten well-functioning THA prostheses retrieved at autopsy. We sought to determine the pull-off strength required for disassembly and to characterize fretting and corrosion apparent at the head-neck junctions of THAs that had been functioning appropriately in vivo. METHODS. Ten cobalt-chromium femoral stems and engaged cobalt-chromium femoral heads were retrieved at autopsy from 9 patients, after a mean length of implantation (LOI) of 11.3 ± 8 years (range 1.9–28.5). Trunnion design and material, femoral head material, size, and length, LOI, and patient sex were recorded (Table 1). Femoral heads were pulled off on a uniaxial load frame according to ASTM standards under displacement control at a rate of 0.05mm/s until the femoral head was fully disengaged from the trunnion. Mating surfaces were gently cleaned with 41% isopropyl alcohol to remove any extraneous debris. Femoral trunnions and head tapers were examined under a stereomicroscope by two independent graders to assess presence and severity of fretting and corrosion (method previously established). Trunnions and tapers were divided into 8 regions: anterior, medial, posterior, and lateral in both proximal and distal zones. Minimum possible damage score per hip was 32 (indicating pristine surfaces). The total possible score per hip was 128 (2 damage modes × 2 mating surfaces × 8 regions × max score of 4 per region). RESULTS. Mean pull-off force among all retrievals was 2446 ± 841 N (1655 – 4246 N). Mean pull-off force for 14/16 tapers (2998 ± 1298 N) was larger than for 12/14 tapers (2210 ± 531 N). Seven retrievals (70%) had no evidence of damage on either the stem or head component (Fig. 1). Three retrievals showed evidence of damage: (1) corrosion in one zone of the femoral head taper (score 33); (2) a circumferential ring of fretting in one zone of the stem trunnion (score 36); (3) circumferential rings of minor fretting in two regions of the stem trunnion (score 40). LOI for damaged retrievals was 16.3 ± 6 years, longer than that for undamaged retrievals (9.1 ± 9.1 years). CONCLUSION. THAs that had been well-functioning in vivo showed little evidence of fretting and corrosion. The presence of minor fretting and corrosion correlated with increased LOI. Mean pull-off force was 2446 +/- 841 N among the complete sample of ten THAs. Larger tapers were associated with greater average pull-off strength. Further investigation is required in order to clarify the clinical implications of these results

We performed a meta-analysis of modern total joint replacement (TJR) to determine the post-operative mortality and the cause of death using different thromboprophylactic regimens as follows: 1) no routine chemothromboprophylaxis (NRC); 2) Potent anticoagulation (PA) (unfractionated or low-molecular-weight heparin, ximelagatran, fondaparinux or rivaroxaban); 3) Potent anticoagulation combined (PAC) with regional anaesthesia and/or pneumatic compression devices (PCDs); 4) Warfarin (W); 5) Warfarin combined (WAC) with regional anaesthesia and/or PCD; and 6) Multimodal (MM) prophylaxis, including regional anaesthesia, PCDs and aspirin in low-risk patients. Cause of death was classified as autopsy proven, clinically certain or unknown. Deaths were grouped into cardiopulmonary excluding pulmonary embolism (PE), PE, bleeding-related, gastrointestinal, central nervous system, and others (miscellaneous). Meta-analysis based on fixed effects or random effects models was used for pooling incidence data. In all, 70 studies were included (99 441 patients; 373 deaths). The mortality was lowest in the MM (0.2%) and WC (0.2%) groups. The most frequent cause of death was cardiopulmonary (47.9%), followed by PE (25.4%) and bleeding (8.9%). The proportion of deaths due to PE was not significantly affected by the thromboprophylaxis regimen (PA, 35.5%; PAC, 28%; MM, 23.2%; and NRC, 16.3%). Fatal bleeding was higher in groups relying on the use of anticoagulation (W, 33.8%; PA, 9.4%; PAC, 10.8%) but the differences were not statistically significant. Our study demonstrated that the routine use of PA does not reduce the overall mortality or the proportion of deaths due to PE

Introduction: The Cambridge Acetabular cup is a unique, uncemented prosthesis that has been designed to transmit load to the supporting bone using a flexible material, carbon fibre reinforced polybutyleneterephthalate (CFRPBT). This should significantly reduce bone loss and provide long term stability. The cup consists of a ultra high molecular weight polyethylene liner within a carbon fibre composite backing that was tested with either a plasma sprayed HA coating or with the coating removed. The cup is a horseshoe shaped insert of similar thickness to the cartilage layer and transmits force only to the regions of the acetabulum originally covered with cartilage. The purpose of this study was to evaluate the response of bone and surrounding tissues to the presence of the cup in retrieved human specimens. Methods: We examined 12 cementless Cambridge acetabular implants that were retrieved at autopsy between 2 and 84 months following surgery. Nine of the implants were coated with HA and three were uncoated. The implant and the surrounding bone were fixed, dehydrated and embedded in polymethylmethacrylate. Sections were cut parallel to the opening of the cup and in two different planes diagonally through the cup. The sections were surface stained with toluidine blue and examined by light microscopy. Image analysis was used to measure the percentage of bone apposition to the implant, the area of bone and fibrous tissue around the implant and the thickness of hydroxyapatite coating. Results: All 9 HA coated implants showed good bone contact with a mean bone apposition and standard deviation of 50.9% +/− 17.5%. The thickness of the HA coating decreased with time and where this was occurring bone remodelling was seen adjacent to the HA surface. However, even in specimens where the HA coating had been removed completely good bone apposition to the CFRPBT remained. Bone marrow was seen apposed to the implant surface where HA and bone had both been resorbed with little or no fibrous tissue. The uncoated implants showed significantly less bone apposition than the HA coated specimens, mean 11.4% +/− 9.9%(p < 0.01) and significant amounts of fibrous tissue at the interface. Discussion: The results of this study indicate that the anatomic design of the Cambridge Cup with a flexible CFRPBT backing and HA coating encourages good bone apposition. In the absence of HA the results are generally poor with less bone apposition and often a fibrous membrane at the implant surface. There was a decrease in HA thickness with time in situ and cell mediated bone remodelling seems to be the most likely explanation of the HA loss. However, good bone apposition was seen to the CFRPBT surface even after complete HA resorption in contrast to the uncoated specimens. Though the mean bone apposition percentage to the HA coated implants declined with time, the bone was replaced by marrow apposed to the implant surface. This is in contrast to the uncoated implants where fibrous tissue becomes apposed to the implant surface. We believe this is due to micro-motion occurring at the bone implant interface. The HA coating appears necessary to provide good initial bone bonding to the implant surface that is maintained even after complete loss of HA

Introduction: Polyethylene wear is an important factor for the longevity of total knee arthroplasty (TKA). One would expect that TKA lasting till death shows no or minimal wear compared to TKA undergoing revision surgery. Material and Method: The present study retrospectively looks at the amount of front side wear on tibial retrievals and correlates clinical and radiological data sampled from these patients’ medical records. All Prostheses are of the same type and company (Stryker Howmedica, Allendale) with the following distribution: PCA 16, PCA modular 19 and Duracon 5. All inserts were gamma sterilized on air. Mean implantation time and mean age at implantation was 100.1 ±55.8 month and 70.7 ±7.4 years respectively. A modified visual score first described by Hood et al. 1983 served as measure for total damage on the polyethylene surface. Statistical Analysis was done by univariate analysis of variance. Results: A highly significant influence on wear was found for the following factors: time of implantation (p< 0.001), kind of TKA design (p< 0.001), TKA belonging to the group of revision (0.016) and age at implantation (p< 0.021). A marginal influence was found for the factors: daily activity (p< 0.076) und kind of patella replacement (p< 0.085). Bodymass index and femorotibial axis had no measurable influence on wear. Discussion: TKA retrieved at autopsy had and astonishingly high amount of wear. As a matter of fact none of the investigated implants was free of delamination, which is the most severe damage mode. In the present sample TKA design and time of implantation had a more important influence on wear than any other factor

Purpose: The purpose of this work was to demonstrate the presence of polyethylene particles at the fixation interfaces of the femoral and acetabular components of non-dislocated cemented hip prostheses that had functioned in vivo for several years.

Material and methods: Three femoral components and two acetabular cups were recovered in two patients who died from an intercurrent cause. The first patient, an 85-year-old woman, had had a hip prosthesis for eight years. There was no radiological sign of displacement nor cup wear (stainless steel /polyethylene cup). For this same patient, the other hip had be revised for acetabular loosening three months prior to death. The femoral component was not loosened; it had been removed with its cement then reimplanted within the same cement sheath that was not removed. The cement/bone interface was thus preserved at eight years. In the second patient, a woman aged 88 years, the delay was nine years. This patient had no radiographic sign of loosening. The polyethylene acetabular insert exhibited 1 mm linear wear. This was a ceramic /polyethylene cup. The specimens were prepared by decalcification and defatting then fixation in buffered formol (pH 7.2) before embedding in polymethyl-metacrylate. After hardening, a diamond-tipped diatome to obtain transverse section of the femur at four levels: lesser trochanter, 2 cm below the lesser trochanter, 1 cm above the tip of the stem, 1 cm below the distal tip of the stem. After polishing, the 50 μ thick sections were stained with Picrofuschin von Jienson. The polyethylene acetabular cups were prepared likewise. Polyethylene particles were counted under polarised optic microscope at each cement /implant and cement /bone interface using an image analyser (Histolab, microvision instruments, Evry, France).

Results: There was no evidence of a fibrous membrane between the bone and the cement. A 10 to 20 mm space was sometimes observed at the metal /cement interface. Polyethylene particles measuring 3 to 10 μm were found at both cement /bone and metal /cement interfaces, including at the distal femur level. Particles were observed in the cement at several sites.

Conclusion: Large-sized polyethylene particles migrate around non-displaced cemented implants, partidularly between bone lines, and can follow the cement poriosity.

Aims. This retrospective study aimed to determine the causes of in-hospital death after Neck of Femur (NOF) fracture in Southampton General Hospital (SGH) over a 6 year period, comparing the clinical cause of death with findings at post-mortem. A previous study showed discrepancies between pre-mortem clinical diagnosis and autopsy findings after in-hospital deaths in SGH. Methods. The study included all patients who died in SGH after NOF fracture from 2007–2013. Case notes were reviewed to determine the pre-mortem clinical diagnosis and compared with the autopsy findings to analyse major and minor discrepancies. Data were also analysed from the period 1997–2003 in order to compare the causes of death. Results. 43 cases were referred for autopsy after NOF fracture during the 6 year study period, of which 39 cases (90.1%) were available for analysis. There was complete agreement between pre-mortem clinical diagnosis and autopsy findings in 64.1% of cases. Major discrepancies were found in 35.9% of cases and minor discrepancies in 23.1% of cases. Causes of death due to bronchopneumonia and pulmonary embolism had decreased significantly during the recent 6 year period when compared with the previous study period. No pulmonary emboli were identified as the primary causes of death between 2007 and 2013. Conclusion. Deaths due to pulmonary emboli after NOF have declined significantly. The reasons for this are unclear and are the subject of an ongoing study which will be discussed. Discrepancies between pre- and post-mortem diagnoses highlight the importance of autopsy findings. The current study revealed a similar rate of major discrepancies compared to the previous study

A recent study of tissues from 14 modern metal-on-metal (MM) total hips reported an intense diffuse and perivascular (p.v.) lymphocytic infiltrate, suggestive of hypersensitivity (Willert et al. Osteologie 2000; 9:2–16). This study evaluated the histopathology of tissues from modern MMs using cases obtained at revision or autopsy. Materials and methods: 35 MM THRs or surface replacements (SRs) that failed due to dislocation, aseptic loosening, and pain or obtained at autopsy (n = 4) were used. H& E stained sections were rated semiquantitatively. Selected cases were studied by immunohistochemistry for macrophage (CD68) and lymphocyte markers (CD3, 4, 20). Wear was measured with a coordinate measuring machine. Results: Generally, the THRs without metallosis showed minimal visible wear particles, consistent with their low measured wear (av. total wear depth was 8.25 ± 6.7 um at av. 30 mos). Although SRs had an av. linear wear depth of 46 ± 48 microns at av. 23 mos, the metal rating was also low (av. 0.8), except in 1 case with HA 3rd body induced high wear and subsequent osteolysis. Lymphocytic aggregates were not a common feature but B type cells were extensive in 1 case (THR revised for pain after 36 months) moderate in 1 autopsy SR (with CoCr metallosis due to run-in wear of an out of round component) and minimal in 4 of the SRs. Discussion and conclusions: Extensive diffuse or p.v. lymphocytes were not a consistent finding in these 35 cases. These features were not seen in well-functioning autopsy retrieved cases with low wear rates, nor in the SR with osteolysis and the highest amount of component wear. Until the long-term local and systemic effects of metal wear products, including hypersensitivity are better understood, continued histopathological assessment of periprosthetic tissues from MM total hips is recommended

Aims: It has been suggested that the capture mechanism of modular polyethylene tibial inserts degrades with time in-situ. This study evaluates micromotion, polyethylene wear and tissue histology in contemporary cemented TKRñs retrieved at autopsy. Methods: Twelve cemented, PCL-retaining TKRñs of the same design were retrieved at autopsy after 41(15–74) months in-situ. Patient age and body weight averaged 73 years and 90 kg, respectively. Insert micromotion was measured according to published protocols on 6 of the 12 TKRñs in which the modular tibial component was undisturbed at retrieval and on 6 unused control components. Tissue histology was evaluated using a semi-quantitative grading system. Articular and backside surface damage was measured using published techniques. Results: There was no signiþcant difference (t-test, p=0.12) between the micro-motion index for retrieved inserts (154±121 um) and control inserts (62±53 um). Backside surface damage covered 38%±23% and was dimpled in appearance without scratching or pitting. Damage covered 46%±8% of the articular surface. Micromotion was negatively correlated with in-situ time (r=−0.94) and backside damage (r=− 0.97). Conclusions: Micromotion for these autopsy-retrieved TKRñs is less than half the 380 micron magnitude measured for other autopsy-retrieved designs, as reported by Engh. Micromotion was greatest on inserts with the least backside wear and the shortest time in-situ. These data suggest that backside damage resulted from axial compression of the polyethylene insert against the baseplate rather than micromotion

Aims: During total knee replacement (TKR), bone dimensions are sometimes between implant sizes. Many surgeons select the smaller tibial component size to avoid overhanging the cortex and the smaller femoral component size to avoid overstuffing the joint space. However, the larger femoral component size is sometimes selected to ensure adequate bone coverage. This study was initiated after contact between the polyethylene insert and posterior femoral osteophytes was observed at autopsy even though radiographs showed adequate osteophyte removal at index TKR. It was hypothesized that knees implanted with the same sized femoral and tibial components would have a higher incidence of contact and abrasive wear than knees with larger femoral components. Methods: Thirty five polyethylene inserts were retrieved at autopsy (34%) and at revision TKR for reasons of infection (20%), patellar complications (17%), loosening (11%), patellar resurfacing (14%), and supracondylar fracture (3%). Mean implantation time was 32(1–74) months. Articular damage was evaluated using light microscopy. Results: Nineteen knees had smaller femoral components and 13 (68%) had abrasive wear on the polyethylene rim. Sixteen knees had larger femoral components and 4 (25%) had the abrasive wear pattern. The incidence of abrasive wear was significantly lower in knees with larger sized femoral components (Fisher’s Exact, p< 0.05). Conclusions: Surgeons are encouraged to remove all osteophytes that might impinge and avoid sizing the components such that the polyethylene insert overhangs the femoral component. Selecting the larger femoral component size may lessen impingement and provide some benefit for increasing knee flexion and decreasing abrasive wear

Despite the earlier work on the bone cement interface in successful Charnley stems lasting 20 years, there is still controversy explaining success and failure of cemented stems. Is it possible to analyse cemented stems histo-pathologically over the whole length of the prosthesis, to show where loosening might start or where the osseous structure resists components' failure?. The purpose of this analysis was to develop histo-pathological procedures, to provide information about bony integration or fibrous encapsulation. This study took place over the past 12 years. Fourteen femoral stems from autopsies, 2 to 26 years post implant - Charnley, Exeter and Muller prosthesis. All clinically and radiologically sound, patients died for reasons unrelated to the implant. Sections were cut in a complete sequence and analysed using a new microscope, the HIIFL microscope, ZOW Munich; thin sections were processed using embedding in epoxy-resin and bloc-staining in alkaline fuchsine. The sequence of sections was performed using a wet-grinding cutting process, ZOW Munich. The analysis resulted in a very simple and unique experience. Independent of how long the implant was in place, there was no or nearly no radiolucent line in the X-ray. In defined compartments, surprisingly, cancellous bone was preserved and in many cases stiffened by bone cement. Bone to cement contacts without interposition of fibrous tissue. The findings might influence the operating techniques in the future. The results were fully coincident to findings in animal experiments of earlier work, including the secondary medullary cavity

Many total knee replacements (TKR) are designed with more conforming articular geometry to increase the femoral contact area and decrease surface stresses. These designs are supported by studies suggesting that implants with coronally flat articular surfaces are vulnerable to medial-lateral lift-off and edge-loading on the polyethylene insert. However, few retrieved inserts from contemporary TKR’s have shown wear consistent with this loading mechanism. This study presents wear measurements from 37 consecutively retrieved polyethylene inserts of the same PCL-retaining design with coronally flat-on-flat articulations. If substantial edge-loading occurred in-vivo, it was hypothesise that wear would be located closer to the medial or lateral edge of the articular surface with a high incidence of delamination. Inserts were retrieved at autopsy (n=12) after 41 (15–74) months in-situ and at revision TKR (n=25) after 26 (1–71) months in-situ. Reason for revision was infection (28%), patellar component complications (24%), loosening (24%), patellar resurfacing (20%), and supra-condylar fracture (4%). Articular damage was measured using light microscopy and digitising the circumference of each damage region on calibrated images. Surface deformation was measured relative to unused control inserts using a hand-held digitising stylus. Wear patterns were not significantly different between autopsy or revision retrievals (ANOVA, p> 0.05). Articular wear covered 48%+16% and 47%+14% of the medial and lateral surfaces, respectively. The most frequent wear modes were burnishing and scratching. Delamination occurred on 4(11%) inserts, but involved < 2% of the articular surface. Wear patterns were internally rotated and centrally located. Not one insert had a wear area centroid located in the medial or lateral third of the articular surface. Surface deformations were greatest in the inserts’ central region and the linear deformation rate decreased with time. Concerns of high contact stresses associated with edge-loading were unsupported by these retrievals. Condylar lift-off, if it occurs, does not appear to substantially impact polyethylene damage in coronally flat-on-flat articulations

Venous thromboembolic events, either deep vein thromboses or pulmonary emboli, are important complications in patients undergoing knee or hip arthroplasty. The purpose of this study was to evaluate the effectiveness of a mobile compression device (ActiveCare+S.F.T.®; Medical Compression Systems, Inc., Or Akiva, Israel) with or without aspirin compared with current pharmacology protocols for venous thromboembolism prophylaxis in patients undergoing elective primary unilateral lower extremity joint arthroplasty. A multicenter registry was established to capture the rate of symptomatic venous thromboemboli following primary lower extremity joint arthroplasty in 3,060 patients from ten sites including knee arthroplasty (1,551) or hip arthroplasty (1,509). All patients were 18 years of age or older with no known history of venous thromboembolism, coagulation disorder, or solid tumor. Use of the compression device began peri-operatively and continued for a minimum of ten days. Patients with symptoms of deep venous thrombosis or pulmonary embolism underwent duplex ultrasonography and/or spiral computed tomography. All patients were evaluated at three months post-operatively to document any evidence of deep venous thrombosis or pulmonary embolism. Of 3,060 patients, twenty-eight (0.92%) had venous thromboembolism (20 distal deep venous thromboses, 3 proximal deep venous thromboses, and 5 pulmonary emboli). One death occurred with no autopsy performed. Symptomatic venous thromboembolic rates observed in lower extremity joint arthroplasty patients using the mobile compression device were non-inferior (not worse than) at a margin of 1.0% to rates reported for pharmacological prophylaxis, including warfarin, enoxaparin, rivaroxaban, and dabigatran except in the knee arthroplasty group where the mobile compression device fell short of rivaroxaban by 0.06%. Use of the mobile compression device with or without aspirin for patients undergoing lower extremity joint arthroplasty provide a non-inferior risk for developing venous thromboembolism compared with current pharmacological protocols reported in the literature

Venous thromboembolic events, either deep vein thromboses or pulmonary emboli, are important complications in patients undergoing knee or hip arthroplasty. The purpose of this study was to evaluate the effectiveness of a mobile compression device (ActiveCare+S.F.T.®; Medical Compression Systems, Inc., Or Akiva, Israel) with or without aspirin compared with current pharmacology protocols for venous thromboembolism prophylaxis in patients undergoing elective primary unilateral lower extremity joint arthroplasty. A multicenter registry was established to capture the rate of symptomatic venous thromboemboli following primary lower extremity joint arthroplasty in 3,060 patients from ten sites including knee arthroplasty (1,551) or hip arthroplasty (1,509). All patients were eighteen years of age or older with no known history of venous thromboembolism, coagulation disorder, or solid tumor. Use of the compression device began perioperatively and continued for a minimum of ten days. Patients with symptoms of deep venous thrombosis or pulmonary embolism underwent duplex ultrasonography and/or spiral computed tomography. All patients were evaluated at three months postoperatively to document any evidence of deep venous thrombosis or pulmonary embolism. Of 3,060 patients, 28 (0.92%) had venous thromboembolism (20 distal deep venous thromboses, 3 proximal deep venous thromboses, and 5 pulmonary emboli). One death occurred with no autopsy performed. Symptomatic venous thromboembolic rates observed in lower extremity joint arthroplasty patients using the mobile compression device were non-inferior (not worse than) at a margin of 1.0% to rates reported for pharmacological prophylaxis, including warfarin, enoxaparin, rivaroxaban, and dabigatran except in the knee arthroplasty group where the mobile compression device fell short of rivaroxaban by 0.06%. Use of the mobile compression device with or without aspirin for patients undergoing lower extremity joint arthroplasty provide a non-inferior risk for developing venous thromboembolism compared with current pharmacological protocols reported in the literature

Venous thromboembolic events, either deep vein thromboses or pulmonary emboli, are important complications in patients undergoing knee or hip arthroplasty. The purpose of this study was to evaluate the effectiveness of a mobile compression device (ActiveCare+S.F.T.®; Medical Compression Systems, Inc., Or Akiva, Israel) with or without aspirin compared with current pharmacology protocols for venous thromboembolism prophylaxis in patients undergoing elective primary unilateral lower extremity joint arthroplasty. A multicenter registry was established to capture the rate of symptomatic venous thromboemboli following primary lower extremity joint arthroplasty in 3,060 patients from ten sites including knee arthroplasty (1,551) or hip arthroplasty (1,509). All patients were eighteen years of age or older with no known history of venous thromboembolism, coagulation disorder, or solid tumor. Use of the compression device began peri-operatively and continued for a minimum of ten days. Patients with symptoms of deep venous thrombosis or pulmonary embolism underwent duplex ultrasonography and/or spiral computed tomography. All patients were evaluated at three months post-operatively to document any evidence of deep venous thrombosis or pulmonary embolism. Of 3,060 patients, twenty-eight (0.92%) had venous thromboembolism (twenty distal deep venous thromboses, three proximal deep venous thromboses, and five pulmonary emboli). One death occurred with no autopsy performed. Symptomatic venous thromboembolic rates observed in lower extremity joint arthroplasty patients using the mobile compression device were non-inferior (not worse than) at a margin of 1.0% to rates reported for pharmacological prophylaxis, including warfarin, enoxaparin, rivaroxaban, and dabigatran except in the knee arthroplasty group where the mobile compression device fell short of rivaroxaban by 0.06%. Use of the mobile compression device with or without aspirin for patients undergoing lower extremity joint arthroplasty provide a non-inferior risk for developing venous thromboembolism compared with current pharmacological protocols reported in the literature

Bone ingrowth fixation of large diameter, beaded cobalt chromium cups is generally considered to be reliable but this is typically judged radiographically. To date, implant retrieval data of attached bone has been limited. This study evaluated correlations between the pre-revision radiographic appearance and the measured amount of bone attachment on one design of porous coated cup. Methods. Twenty-six monoblock, CoCr Birmingham Hip Resurfacing (BHR, Smith and Nephew, TN, USA) cups with macroscopic beads and hydroxyapatite coating were studied. Seventeen were revised for acetabular malposition with the remainder revised for femoral loosening (4), pain (1), infection (1), dislocation (1) or lysis (2). Median time to revision was 35 months (10 – 70 months). Ten patients were female; the median age of all patients was 54 years. The pre-revision radiographs were visually ranked for cup-bone integration as follows: 0 = none, 1 = < 50%, 2 = 50 – 75%, 3 = 76 – 95%, 4 = > 96% integration. Rankings were made for the superior and inferior aspects, without knowledge of the appearance of bone on the retrievals. The revised cups were photographed at an angle so the dome and the cup periphery were visualized. The area of bone in four equal segments in each of the superior and inferior aspects was measured with image analysis software. A probe was used to differentiate bone from soft tissue. Only bone that covered the beads was counted. Correlation coefficients were calculated for the radiographic and image analysis data. Results. Radiographically, most cups were assessed as having more than 50% of bone attachment and 7 cups were ranked as having almost total integration with bone. Only 2 cups were assessed radiographically as fully loose. Measured total bone attachment ranged from none to 55%. Superior and inferior percent ingrowth were highly correlated (corr=0.68, p<0.001) but there was no correlation between percent bone and x-ray rank (inferior corr=0.01, p=0.96; superior corr=0.23, p=0.26). There was no correlation between cup malpositioning as a reason for revision and x-ray integration ranking (superior p=0.34; inferior p=0.80). Discussion. Despite the radiographic appearance of good fixation, there was little or no correlation between percent area of actual bone attachment and x-ray appearance. One study limitation is the assumption that attached bone was indeed integrated with the beads as destructive sectioning was not done to verify this. Published autopsy retrieval studies have shown that even a small amount of actual ingrowth can provide clinically successful fixation. Another possible limitation was the variable quality of the radiographs. Never-the-less these results raise questions about the accuracy of radiographic analysis of bone fixation. The possibility that inadequate fixation is a cause for pain leading to revision should be considered even when the radiographic appearance indicates otherwise

Venous thromboembolic events, either deep vein thromboses or pulmonary emboli, are important complications in patients undergoing knee or hip arthroplasty. The purpose of this study was to evaluate the effectiveness of a mobile compression device (ActiveCare+S.F.T.®; Medical Compression Systems, Inc., Or Akiva, Israel) with or without aspirin compared with current pharmacology protocols for venous thromboembolism prophylaxis in patients undergoing elective primary unilateral lower extremity joint arthroplasty. A multicenter registry was established to capture the rate of symptomatic venous thromboemboli following primary lower extremity joint arthroplasty in 3,060 patients from ten sites including knee arthroplasty (1,551) or hip arthroplasty (1,509). All patients were eighteen years of age or older with no known history of venous thromboembolism, coagulation disorder, or solid tumor. Use of the compression device began perioperatively and continued for a minimum of ten days. Patients with symptoms of deep venous thrombosis or pulmonary embolism underwent duplex ultrasonography and/or spiral computed tomography. All patients were evaluated at three months postoperatively to document any evidence of deep venous thrombosis or pulmonary embolism. Of 3,060 patients, twenty-eight (0.92%) had venous thromboembolism (twenty distal deep venous thromboses, three proximal deep venous thromboses, and five pulmonary emboli). One death occurred with no autopsy performed. Symptomatic venous thromboembolic rates observed in lower extremity joint arthroplasty patients using the mobile compression device were non-inferior (not worse than) at a margin of 1.0% to rates reported for pharmacological prophylaxis, including warfarin, enoxaparin, rivaroxaban, and dabigatran except in the knee arthroplasty group where the mobile compression device fell short of rivaroxaban by 0.06%. Use of the mobile compression device with or without aspirin for patients undergoing lower extremity joint arthroplasty provides a non-inferior risk for developing venous thromboembolism compared with current pharmacological protocols reported in the literature

1) A case is reported of paraplegia with normal radiographic appearances in which cervical cord damage was shown at autopsy to have been due to hyperextension injury. 2) The mechanism of such injuries is discussed, together with the differential diagnosis from acute prolapse of an intervertebral disc. 3) The grave dangers of using the fully extended position of the cervical spine in the management of these cases is noted