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BACKGROUND: Adverse local tissue reaction (ALTR) is a recognized complication of total hip arthroplasty (THA) with metal-on-polyethylene (MoP) bearing surface implants. Specific models of THA implants have been identified as having a higher incidence of ALTR. The purpose of this study is to determine if serum metal levels, patient symptoms, implant factors, and imaging findings can be predictive of ALTR within this high-risk population. METHODS: We retrospectively reviewed an observational cohort of 474 patients who underwent MoP THA and were at increased risk of having ALTR. Patients were stratified based on the presence or absence of ALTR. Patient symptoms, serum metal ions, implant head offset, and imaging findings were compared. RESULTS: Patients with ALTR were more likely to be symptomatic (52.9% vs 9.9%, P < .0001). The presence of ALTR was associated with significantly higher serum cobalt and chromium levels (6.2 ppb vs 3.6 ppb, P < .0001; 2.3 ppb vs 1.2 ppb, P < .0001). Head offsets greater than 4 mm were associated with a higher prevalence of ALTR (53% vs 38%, P = .05). On metal artifact reduction sequence magnetic resonance imaging, patients with ALTR had larger effusions (4.7 cm vs 2.1 cm, P < .001) and a higher incidence of trochanteric bursitis (47% vs 16%, P < .001). CONCLUSIONS: In high-risk MoP implants, serum cobalt and chromium levels are elevated, even in patients without ALTR. A larger femoral head offset is a risk factor for the development of ALTR. Our study suggests that patients presenting with painful THA and elevated metal ions require risk stratification based on patient symptoms, metal artifact reduction sequence magnetic resonance imaging findings, and implant factors.

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BACKGROUND: Diagnosis of adverse local tissue reaction (ALTR) in metal-on-polyethylene (MoP) total hip arthroplasty (THA) secondary to head-neck taper corrosion is challenging. The purpose of this study is to compare differences between asymptomatic and symptomatic ALTR in an observational cohort, including presentation, metal ion differences, and metal artifact reduction sequence (MARS) magnetic resonance imaging (MRI) findings. METHODS: We performed a retrospective review of an observational cohort of 492 MoP THA patients at increased risk of developing ALTR. Ninety-four patients underwent revision arthroplasty for ALTR. Patients were stratified into symptomatic and asymptomatic ALTR groups. Presentation, metal ion levels, and imaging findings were compared. RESULTS: For patients with confirmed ALTR, 41% were asymptomatic. There was a statistically significant difference in the serum chromium levels between symptomatic and asymptomatic ALTR patients (2.2 µg/L vs 3.1 µg/L, P = .05). There was no statistically significant difference between the serum cobalt levels or MRI findings in these 2 groups. We observed that extracapsular disease associated with ALTR could be misinterpreted as trochanteric bursitis. CONCLUSION: Almost half of the MoP THA ALTR cases identified were asymptomatic. Cobalt levels could not differentiate between symptomatic and asymptomatic pseudotumor formation. Symptomatic and asymptomatic MoP ALTRs have similar MARS MRI characteristics. Our findings suggest that it is essential to risk stratify patients who could potentially have ALTR based on implant type, symptoms, ion levels, and MARS MRI.

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BACKGROUND: The use of multimodal pain regimens has been shown to be an effective technique for the treatment of postoperative pain after total knee arthroplasty. Periarticular injections, of both short-acting and long-acting anesthetics, have emerged as an additional method of providing significant improvement in postoperative pain relief. The purpose of this study is to compare the efficacy of periarticular injection using long-acting vs short-acting preparations. METHODS: A randomized, prospective study of 80 consecutive patients was performed comparing liposomal bupivacaine vs plain bupivacaine periarticular injection. The primary outcomes included pain relief, total narcotic usage, and completion of physical therapy goals, specifically range of motion. RESULTS: No significant improvements were noted between liposomal bupivacaine and plain bupivacaine injection groups in overall pain reduction, range of motion, or total narcotic usage. At 24 hours, small statistically significant differences in physical therapy pain scores were noted with liposomal bupivacaine vs plain bupivacaine and control patients, but these differences did not persist at later time points. Both preparations demonstrated statistically significant improvements in range of motion when compared to historical controls, but no differences were noted between preparations. CONCLUSION: Overall, minimal significant differences were noted between liposomal bupivacaine and plain bupivacaine at early and late time points. Both preparations of periarticular injection demonstrated superiority over control pain regimens but were relatively equivalent to one another in direct comparison.

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BACKGROUND: Gross trunnion failure (GTF) is a rare complication in total hip arthroplasty (THA) reported across a range of manufacturers. Specific lots of the Stryker low friction ion treatment (LFIT) anatomic cobalt chromium alloy (CoCr) V40 femoral head were recalled in August 2016. In part, the recall was based out of concerns for disassociation of the femoral head from the stem and GTF. METHODS: We report on 28 patients (30 implants) with either GTF (n = 18) or head-neck taper corrosion (n = 12) of the LFIT CoCr femoral head and the Accolade titanium-molybdenum-zirconium-iron alloy femoral stems. All these cases were associated with adverse local tissue reactions requiring revision of the THA. RESULTS: In our series, a conservative estimate of the incidence of failure was 4.7% (n = 636 total implanted) at 8.0 ± 1.4 years from the index procedure. Failures were associated with a high-offset 127° femoral stem neck angle and increased neck lengths; 43.3% (13 of 30) of the observed failures included implant sizes outside the voluntary recall (27.8% [5 of 18] of the GTF and 75.0% [8 of 12] of the taper corrosion cases). Serum cobalt and chromium levels were elevated (cobalt: 8.4 ± 7.0 µg/mL; chromium: 3.4 ± 3.3 µ/L; cobalt/chromium ratio: 3.7). The metal artifact reduction sequence magnetic resonance imaging demonstrated large cystic fluid collections typical with adverse local tissue reactions. During revision, a pseudotumor was observed in all cases. Pathology suggested a chronic inflammatory response. Impending GTF could be diagnosed based on aspiration of black synovial fluid and an oblique femoral head as compared with the neck taper on radiographs. CONCLUSION: In our series of the recalled LFIT CoCr femoral head, the risk of impending GTF or head-neck taper corrosion should be considered as a potential diagnosis in a painful LFIT femoral head and Accolade titanium-molybdenum-zirconium-iron alloy THA with unknown etiology. Almost half of the failures we observed included sizes outside of the voluntary recall.

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The objective of this study is to compare the effectiveness of intravenous versus topical application of tranexamic acid in patients undergoing knee arthroplasty. All patients who underwent primary knee arthroplasty at our total joint center over a 12-month period were included in the study. One surgeon utilized 1 g of IV TXA at time of incision in all patients (n=373) except those with a documented history of venous thromboembolism (VTE). Two surgeons utilized a topical application of TXA for all patients without exception (n=198) in which the joint was injected after capsular closure with 3 g TXA/100 mL saline. The transfusion rate was 0% in the topical group vs. 2.4% in the IV group and this was statistically significant (P<0.05).

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Osteoblast response was evaluated with polymethylmethacrylate (PMMA)/titanium dioxide (TiO2) nanocomposite thin films that exhibit the controllable wettability with ultraviolet (UV) treatment. In this study, three samples of PMMA/TiO2 were fabricated with three different compositional volume ratios (i.e., 25/75, 50/50, and 75/25) followed by UV treatment for 0, 4, and 8 h. All samples showed the increased hydrophilicity after UV irradiation. The films fabricated with the greater amount of TiO2 and treated with the longer UV irradiation time increased the hydrophilicity more. The partial elimination of PMMA on the surface after UV irradiation created a durable hydrophilic surface by (1) exposing higher amount of TiO2 on the surface, (2) increasing the hydroxyl groups on the TiO2 surface, and (3) producing a mesoporous structure that helps to hold the water molecules on the surface longer. The partial elimination of PMMA on the surface was confirmed by Fourier transform infrared spectroscopy. Surface profiler and atomic force microscopy demonstrated the increased surface roughness after UV irradiation. Both scanning electron microscopy and energy-dispersive X-ray spectroscopy demonstrated that particles containing calcium and phosphate elements appeared on the 8 h UV-treated surface of PMMA/TiO2 25/75 samples after 4 days soaking in Dulbecco's Modified Eagle Medium. UV treatment showed the osteoblast adhesion improved on all the surfaces. While all UV-treated hydrophilic samples demonstrated the improvement of osteoblast cell adhesion, the PMMA/TiO2 25/75 sample after 8 h UV irradiation (n = 5, P value = 0.000) represented the best cellular response as compared to other samples. UV-treated PMMA/TiO2 nanocomposite thin films with controllable surface properties represent a high potential for the biomaterials used in both orthopedic and dental applications.

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BACKGROUND: We are not aware of any clinical studies in the literature comparing the results of vascularized and nonvascularized fibular grafting for the treatment of osteonecrosis of the femoral head. The purpose of this study was to compare the clinical results of free vascularized fibular grafting with those of nonvascularized fibular grafting. METHODS: Two hundred patients (220 hips) with osteonecrosis of the femoral head were treated with free vascularized fibular grafting at the University of Pittsburgh Medical Center, and ninety-nine patients (123 hips) were treated with nonvascularized fibular grafting at the Kyungpook National University Hospital in Korea. From these populations, two groups of fifty hips each, followed for a minimum of three years (average, five years), were matched by the stage, size, and etiology of the lesion and by the mean preoperative Harris hip score. A retrospective case-control study of these groups was then performed to compare the postoperative Harris hip scores as well as the prevalences of radiographic progression and collapse of the femoral head following free vascularized fibular grafting with those measures following nonvascularized fibular grafting. RESULTS: The mean Harris hip score improved for 70% of the hips treated with free vascularized fibular grafting: seventeen hips (34%) were rated excellent, fourteen (28%) were rated good, nine (18%) were rated fair, and ten (20%) were rated poor. The mean Harris hip score improved for 36% of the hips treated with nonvascularized fibular grafting: five hips (10%) were rated excellent; nine (18%), good; sixteen (32%), fair; and twenty (40%), poor. The rate of survival at seven years for the Stage-I and II hips (precollapse) was 86% after treatment with free vascularized fibular grafting compared with 30% after nonvascularized fibular grafting. CONCLUSIONS: The results of this study strongly suggest that vascularized fibular grafting is associated with better clinical and radiographic results.

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This prospective study compares a mini-incision technique and traditional posterior approach for total hip arthroplasty (THA). Thirty-three patients who had undergone a mini-incision THA were matched by diagnosis, gender, average age, and preoperative Harris Hip Score (HHS) to 33 patients who had undergone THA using the traditional posterior approach. The average length of the incision for group 1 was 11.7 cm (range, 7.3-13.0) and for group 2 was 20.2 cm (range, 14.8-26.0). At the 3-month follow-up, patients in the mini-incision group had significant improvement in limp (P<.05) and ability to climb stairs (P <.01) compared with the traditional group. At the 6 month follow-up, the mini-incision group was significantly better in terms of limp (P <.05), distance walked (P<.001), and stairs (P < 0.001). There was no significant difference between groups for pain, function, or range of motion at the 1-year follow-up examination.

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We hypothesized that use of mechanical acetabular guides for intraoperative alignment leads to variations between the actual and desired implant orientation. Acetabular implant orientation using only the mechanical guide was studied in 78 patients (82 hips) undergoing primary total hip arthroplasty. A computer-assisted navigation system was used to measure alignment and to monitor the orientation of the pelvis during surgery. When using the mechanical guide, there was significant variation in cup alignment from the desired goal of 45 degrees of abduction and 20 degrees of flexion, and this would have resulted in unacceptable acetabular alignment in 78% of hips. With the support system used, there was significant variability in pelvic orientation during surgery. The mean anteversion of the pelvis was an average of 18 degrees from the optimal orientation. These results show a clear need to develop more reliable tools than were used or anatomically based alignment strategies to provide reproducible and accurate acetabular alignment.

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