Meta-Analysis Comparing Valve-in-Valve Transcatheter Mitral Valve Replacement Versus Redo Surgical Mitral Valve Replacement in Degenerated Bioprosthetic Mitral Valve.

Valve-in-valve transcatheter mitral valve replacement (ViV-TMVR) and redo surgical mitral valve replacement (redo-SMVR) are 2 treatment strategies for patients with bioprosthetic mitral valve dysfunction. We conducted a systematic review and meta-analysis to compare the outcomes of ViV-TMVR versus redo-SMVR. We searched PubMed, EMBASE, Cochrane, and Google Scholar for studies comparing outcomes of ViV-TMVR versus redo-SMVR in degenerated bioprosthetic mitral valves. We used a random-effects model to calculate odd ratios (ORs) with 95% confidence intervals (CIs). Outcomes included in-hospital, 30-day, 1-year, and 2-year mortality, stroke, bleeding, acute kidney injury, arrhythmias, permanent pacemaker insertion, and hospital length of stay (LOS). A total of 6 observational studies with 707 subjects were included. The median follow-up was 2.7 years. Despite their older age and greater co-morbidity burden, patients who underwent ViV-TMVR had a similar in-hospital mortality (OR 0.52, 95% CI 0.22 to 1.23, p = 0.14), 30-day mortality (OR 0.65, 95% CI 0.36 to 1.17, p = 0.15), 1-year mortality (OR 0.97, 95% CI 0.63 to 1.49, p = 0.89), and 2-year mortality (OR 1.17, 95% CI 0.65 to 2.13, p = 0.60) compared with redo-SMVR. ViV-TMVR was associated with significantly lower periprocedural complications, including stroke, bleeding, acute kidney injury, arrhythmias, and permanent pacemaker insertion, and shorter hospital LOS than redo-SMVR. In conclusion, ViV-TMVR was associated with better outcomes than redo-SMVR in patients with degenerated bioprosthetic mitral valves, including lower complication rates and shorter hospital LOS, with no significant difference in mortality rates. Large-scale randomized trials are needed to mitigate biases and confirm our findings.

The Influences of Spinopelvic Parameters and Associated Factors on Development of Proximal Instrumented Fracture After Posterior Instrumentation.

OBJECTIVE: To investigate influences of spinopelvic parameters, such as lumbar lordosis (LL) angles, pelvic incidence, sacral slope, pelvic tilt, and sagittal vertical axis, on development of the proximal junctional failure fracture type after posterior instrumentation. METHODS: This retrospective 1:3 matched case-control cohort study included 24 patients who developed proximal instrumented fracture in the study group and 72 patients without proximal junctional failure in the control group. Weighted Charlson Comorbidity Index and bone mineral density with T-score were recorded. In addition to spinopelvic parameters, proximal local kyphosis (PLK), which refers to a kyphosis angle between the upper end plate of upper instrumented vertebra plus 1 level and the lower end plate of upper instrumented vertebra; pelvic incidence-LL mismatch; and spinopelvic realignment score were calculated. RESULTS: More comorbidities (Charlson Comorbidity Index, P = 0.002) and poorer bone density (T-score, P = 0.001) were noted in the study group. Before surgery, the study group had significantly lower LL (P = 0.046) and sacral slope (P = 0.043) and significantly higher PLK (P < 0.001) and pelvic tilt (P = 0.044) than the control group. Postoperatively, the study group had significantly higher PLK (P < 0.001) and lower LL (P = 0.031) than the control group; the degree of pelvic incidence-LL mismatch (P = 0.007) remained significantly higher in the study group. Preoperative (P = 0.026) and postoperative (P = 0.045) spinopelvic realignment scores was worse in the study group. Multivariate analysis revealed that postoperative PLK was the most significant radiographic factor to predict proximal instrumented fracture (P = 0.002, odds ratio 1.140, 95% confidence interval). CONCLUSIONS: In our experience, appropriate LL and lower PLK should be obtained at surgery to prevent development of instrumented fracture.

Acute failure of S2-alar-iliac screw pelvic fixation in adult spinal deformity: novel failure mechanism, case series, and review of the literature.

OBJECTIVE: Pelvic fixation with S2-alar-iliac (S2AI) screws is an established technique in adult deformity surgery. The authors' objective was to report the incidence and risk factors for an underreported acute failure mechanism of S2AI screws. METHODS: The authors retrospectively reviewed a consecutive series of ambulatory adults with fusions extending 3 or more levels, and which included S2AI screws. Acute failure of S2AI screws was defined as occurring within 6 months of the index surgery and requiring surgical revision. RESULTS: Failure occurred in 6 of 125 patients (5%) and consisted of either slippage of the rods or displacement of the set screws from the S2AI tulip head, with resultant kyphotic fracture. All failures occurred within 6 weeks postoperatively. Revision with a minimum of 4 rods connecting to 4 pelvic fixation points was successful. Two of 3 (66%) patients whose revision had less fixation sustained a second failure. Patients who experienced failure were younger (56.5 years vs 65 years, p = 0.03). The magnitude of surgical correction was higher in the failure cohort (number of levels fused, change in lumbar lordosis, change in T1-pelvic angle, and change in coronal C7 vertical axis, each p < 0.05). In the multivariate analysis, younger patient age and change in lumbar lordosis were independently associated with increased failure risk (p < 0.05 for each). There was a trend toward the presence of a transitional S1-2 disc being a risk factor (OR 8.8, 95% CI 0.93-82.6). Failure incidence was the same across implant manufacturers (p = 0.3). CONCLUSIONS: All failures involved large-magnitude correction and resulted from stresses that exceeded the failure loads of the set plugs in the S2AI tulip, with resultant rod displacement and kyphotic fractures. Patients with large corrections may benefit from 4 total S2AI screws at the time of the index surgery, particularly if a transitional segment is present. Salvage with a minimum of 4 rods and 4 pelvic fixation points can be successful.

Early unexpected failure of a vitamin E-infused highly cross-linked polyethylene liner: A case report.

RATIONALE: Total hip arthroplasty (THA) with a polyethylene (PE) liner is 1 of the most effective and successful treatment strategies for end-stage hip disorders. Vitamin E-infused highly cross-linked polyethylene is theoretically known to prevent failure due to oxidative degradation in the body, and is resistant to wear; therefore, successful long-term survival of THA is expected. PATIENT CONCERNS: In June 2019, approximately 1.5 years after THA, the patient sat down and stood up without any specific issue; however, an unusual bullet sound occurred around the left hip joint. Since then, his discomfort persisted, and he was admitted to the emergency department. DIAGNOSIS: Plain radiography and metal artifact reduction computed tomography performed in the emergency department revealed eccentric elevation of the prosthetic femoral head and suspected PE liner failure. INTERVENTION: Revision surgery was performed for modular component exchange. To reduce the dislocation risk without performing cup exchange, conversion to dual-mobility articulation was performed. OUTCOMES: During the regular follow-up post-surgery, the patient could perform daily life activities without any discomfort, and dislocation was not observed. At 2 years postoperatively, no significant changes were observed in the radiographic images. LESSONS: This case report presents an unexpected failure of THA due to superior rim fracture and excessive wear at the locking mechanism of the vitamin E-infused highly cross-linked polyethylene liner. This is an interesting case, as early PE liner failure occurred without strong labor intensity or trauma. A modular component exchange was performed with a dual-mobility bearing, and no issues were observed approximately 2 years after the reoperation. Therefore, third-generation highly cross-linked polyethylene liners can also cause early failure without a clear cause, and this case report highlights the necessity of considering several strategies for reoperation. STUDY DESIGN: Case report.

The risk of revision following total hip arthroplasty in patients with inflammatory bowel disease, a registry based study.

Inflammatory bowel disease (IBD) is characterized by chronic inflammation of the intestinal tract and is associated with decreased bone mineral density. IBD patients are at higher risk of osteopenia, osteoporosis and fracture compared to non-IBD patients. The impact of IBD on the performance of orthopedic implants has not been well studied. We hypothesized that a history of IBD at the time of primary total hip arthroplasty (THA) would increase the risk of subsequent failure as assessed by revision surgery. A retrospective implant survival analysis was completed using the Swedish Hip Arthroplasty Registry and the Sweden National Patient Register. A total of 150,073 patients undergoing THA for osteoarthritis within an 18-year period were included in the study. THA patients with (n = 2,604) and without (n = 147,469) a history of IBD at the time of THA were compared with primary revision as the main endpoint and adjusted using sex, age category and comorbidity (Elixhauser scores) as covariates. We found that patients with a history of IBD had a relatively higher risk of revision surgery for septic causes while the non-IBD patients had a relatively higher risk of revision for aseptic causes (p = 0.004). Our findings suggest there may be an association between gut health and THA performance.

Trunnionosis and metal wear causing metal hypersensitivity: 2 sides of the same coin?

Metal hypersensitivity (MHS) and trunnionosis are being looked at more frequently. Both entities pose a difficult concern for surgeons and patients alike. This commentary highlights the similarities and differences between the 2 conditions. When a surgeon suspects either MHS or trunnionosis, both should be considered in the differential diagnosis. Both conditions are rare and should be considered a diagnosis of exclusion. The commentary proposes an outline on how to diagnose and treat the 2 entities.

Pseudarthrosis and Rod Fracture Rates After Transforaminal Lumbar Interbody Fusion at the Caudal Levels of Long Constructs for Adult Spinal Deformity Surgery.

BACKGROUND: Interbody fusion at the caudal levels of long constructs for adult spinal deformity (ASD) surgery is used to promote fusion and secure a solid foundation for maintenance of deformity correction. We sought to evaluate long-term pseudarthrosis, rod fracture, and revision rates for TLIF performed at the base of a long construct for ASD. METHODS: We reviewed 316 patients who underwent TLIF as a component of ASD surgery for medical comorbidities, surgical characteristics, and rate of unplanned reoperation for pseudarthrosis or instrumentation failure at the TLIF level. Fusion grading was assessed after revision surgery for pseudarthrosis at the TLIF level. RESULTS: Rate of pseudarthrosis at the TLIF level was 9.8% (31/316), and rate of rod fractures was 7.9% (25/316). The rate of revision surgery at the TLIF level was 8.9% (28/316), and surgery was performed at a mean of 20.4 ± 16 months from the index procedure. Current smoking status (odds ratio 3.34, P = 0.037) was predictive of pseudarthrosis at the TLIF site. At a mean follow-up of 43 ± 12 months after revision surgery, all patients had achieved bony union at the TLIF site. CONCLUSIONS: At 3-year follow-up, the rate of pseudarthrosis after TLIF performed at the base of a long fusion for ASD was 9.8%, and the rate of revision surgery to address pseudarthrosis and/or rod fracture was 8.9%. All patients were successfully treated with revision interbody fusion or posterior augmentation of the fusion mass, without need for further revision procedures at the TLIF level.

Adverse Events due to Lack of Precision in Total Hip Arthroplasty: The Potential of Provocation-Based CT for Diagnosis of Implant Loosening.

Adverse events in total hip replacement (THR) may have several origins, one being lack of precision in diagnosis and/or during surgery. This study describes the pattern and frequency of avoidable injuries in THR and the potential value of a new tool for early diagnosis of implant loosening. This retrospective study was based on all (n = 1 456) settled claims regarding THR in the Swedish National Patient Insurance database from 2010 to 2017. The claims and medical records were analyzed for root causes, with special focus on adverse events where lack of precision could be the cause. In a second stage, we assessed in 10 patients (20 implants) the diagnostic precision of a new software tool based on provocation-CT. These were all patients where the implant loosening diagnosis was deemed as inconclusive after a first plain X-ray. The findings from the provocation-CT and plain X-ray were compared to the surgical findings at revision. While 3 of 20 implants were correctly diagnosed with plain X-ray, for dynamic CT, this number was 14 of 20 implants. The retrospective study showed that the most common types of injuries were infections (34%), nerve injury (29%), mechanical problems (14.5%), dislocation (6%), and miscellaneous complications (16.5%). Of the patients with mechanical complications, one-third had aseptic implant loosening. Statement of clinical significance: we estimated that almost 200 patients in our registry study had mechanical complications after THR, mainly implant loosening. A third of these could potentially have been diagnosed and treated if CT examination with a dedicated image analysis tool to assess implant loosening after THR had been available.

One Year Outcomes of an International Multicentre Prospective Cohort Study on the Gore Excluder Iliac Branch Endoprosthesis for Aorto-Iliac Aneurysms.

OBJECTIVE: The Gore Excluder Iliac Branch Endoprosthesis (IBE) was developed to preserve perfusion in the hypogastric artery after endovascular repair of aorto-iliac aneurysms. This study reports the 12 month technical and clinical outcomes of treatment with this device. METHODS: This study was a physician initiated international multicentre, prospective cohort study. The primary endpoint was primary patency of the hypogastric branch at 12 months. Secondary endpoints included technical and clinical outcomes. Patients with an indication for elective treatment with the Gore Excluder IBE were enrolled between March 2015 and August 2018. Baseline and procedural characteristics, imaging data, physical examinations and questionnaire data (Walking Impairment Questionnaire [WIQ], EuroQol-5-Dimensions [EQ5D], International Index of Erectile Function 5 [IIEF-5]) were collected through 12 month follow up. RESULTS: One hundred patients were enrolled of which 97% were male, with a median age of 70.0 years (interquartile range [IQR] 64.5 - 75.5 years). An abdominal aortic aneurysm (AAA) above threshold for treatment was found in 42.7% and in the remaining patients the iliac artery diameter was the indication for treatment. The maximum common iliac artery (CIA) diameter on the Gore Excluder IBE treated side was 35.5 mm (IQR 30.8 - 42.0) mm. Twenty-two patients received a bilateral and seven patients had an isolated IBE. Median procedural time was 151 minutes (IQR 117 - 193 minutes) with a median hospital stay of four days (IQR 3 - 5 days). Primary patency of the IBE at 12 month follow up was 91.3%. Primary patency for patients treated inside and outside the instructions for use were 91.8% and 85.7%, respectively (p = .059). Freedom from secondary interventions was 98% and 97% at 30 days and 12 months, respectively. CIA and AAA diameters decreased significantly through 12 months. IIEF-5 and EQ5D scores remained stable through follow up. Patency of the contralateral internal iliac artery led to better IIEF-5 outcomes. WIQ scores decreased at 30 days and returned to baseline values through 12 months. CONCLUSION: Use of the Gore Excluder IBE for the treatment of aorto-iliac aneurysms shows a satisfactory primary patency through 12 months, with significant decrease of diameters, a low re-intervention rate, and favourable clinical outcomes.

Highly cross-linked polyethylene still outperforms conventional polyethylene in THA: 10-year RSA results.

Background and purpose - Cup wear in total hip arthroplasty (THA) can be affected by different manufacturing processes of the polyethylene (PE). We report the long-term wear pattern differences, as well as early creep behavior, between conventional PE and highly cross-linked PE (HXLPE) liners, as measured with radiostereometry (RSA) up to 10 years. We also compare migration and clinical outcome of 2 similar uncemented cups with different backside surface roughness.Patients and methods - We included 45 patients with primary osteoarthritis. 23 received a conventional liner and 22 an HXLPE liner in a similar uncemented cup, but with a slightly rougher surface. The patients were followed up with RSA and hip-specific outcome questionnaire (HOOS) at 3 months, 1, 2, 5, and 10 years.Results - During the first 3 months both liners showed expected deformation with mean proximal head penetration of 0.39 mm (conventional PE) and 0.21 mm (HXLPE). Between 3 months and 10 years there was a difference in annual wear with 0.12 mm/year for the conventional liner and 0.02 mm/year for the HXLPE liner. The cup with rougher surface had less initial migration but both types had stabilized after 3 months. The HOOS scores improved after surgery and remained high for both groups throughout the study period.Interpretation - Up to 10 years the HXLPE has consistent lower annual wear, possibly contributing to longer survival of the THA, compared with conventional PE. All patients reported good results regardless of liner type.

Anterior Odontoid Screw Fixation for Pediatric and Adolescent Odontoid Fractures: Single-Center Experience Over a Decade.

OBJECTIVE: Management of pediatric odontoid fractures is tricky and controversial. This study will enrich world literature with intricacies of anterior odontoid screw (OS) fixation in the pediatric population learned over the last decade. METHODS: In this retrospective study, all patients with pediatric odontoid fracture who underwent anterior odontoid screw fixation from January 2010 to December 2019 were included and evaluated for surgical outcome. RESULTS: Thirteen patients were included in this study (mean age, 15 years; range, 6-18 years; male/female, 11:2; type II, 10; type IIA, 1; type III, 2). Common causes of injury were motor vehicle accidents (61.5%) followed by fall from height (38.5%) and all were acute fractures (2-30 days). Five patients had neurologic deficits. Accurate placement of screw was achieved in 92.3% of patients, including all 9 patients who used intraoperative O-arm. K wire migration during bicortical drilling resulted in neurovascular injury, with 1 mortality (7.7%). The remaining 12 patients were available for follow-up (mean, 36 months; range, 20-72 months) and all had preservation of neck movements. Successful OS fixation was achieved in 84.6% of patients, including 1 patient (7.7%) who had a fibrous union. One patient (8.3%) had nonunion because of migration of the screw head in the C2 body. CONCLUSIONS: Anterior odontoid screw fixation in the pediatric population provides good functional outcomes with instant fixation by direct osteosynthesis. However, the surgeon should be meticulous in the surgical approach and should achieve a lag effect. The surgeon should stop after engaging the outer cortex of the odontoid peg with K wire to avoid cranial migration. Intraoperative O-arm guidance is useful.

Unusual Cause of Unilateral Breast Swelling.

A 69-year-old woman with bilateral breast implants and a newly inserted ventriculoperitoneal shunt presented with a 4-day history of swelling of the right breast. There were no signs of infection and blood tests were normal. With the help of ultrasound, mammogram, and computed tomography, the distal catheter of the shunt was found to be surrounding the right breast implant. During surgery the catheter was tunneled away from the breast and reinserted into the peritoneal cavity. She was discharged the next day. Ventriculoperitoneal shunt migration to the breast is a rare complication that can lead to cerebrospinal fluid accumulation and may be avoided by carefully tunneling away from the implant.

Catastrophic failure and metallosis of the acetabular component in total hip arthroplasty.

BACKGROUND: To evaluate the clinical features and results of the revision total hip arthroplasties (THA) in patients with catastrophic failures and metallosis. METHODS: Fifteen hips of 14 patients with catastrophic failure and metallosis in hip arthroplasties were evaluated. They were followed for at least 4.2 years after the revision THA. Clinical evaluation was performed using Harris hip score. Osteolysis, loosening or presence of metallosis was evaluated with standard radiographs. Metallosis was evaluated intraoperatively according to the metallosis severity classification. RESULTS: The mean time from failure until revision surgery was 9.4 years. It was observed that in the primary THA, metal-on-ceramic (MoC), ceramic-on-ceramic (CoC) and metal-on-conventional polyethylene (MoCPE) bearings were used in 1, 3 and 11 hips, respectively. Grade III metallosis was observed in all patients during revision surgeries. The mean Harris hip score increased from 55 points before revision THA to 75 points at the final follow-up. In revision arthroplasty, MoCPE and CoC bearings were used in 13 and 2 hips, respectively. The femoral stem was replaced in 5 hips. All acetabular cups, except that of one hip, were revised. CONCLUSIONS: Revisions of THAs with catastrophic failures and metallosis are quite challenging. Routine follow-up of arthroplasty patients is beneficial to examine for osteolysis, loosening, and asymmetric wear.

Arthroscopy-Assisted Treatment of Wear Debris Pseudotumor After Total Knee Arthroplasty: A Case Report.

BACKGROUND: Wear debris pseudotumors are a rare complication after total knee arthroplasty (TKA) and have seldom been reported in the recent literature. There is no consensus on the best therapeutic method, but the high quality curative treatment, safe, low invasive treatments are required for the patients. CASE PRESENTATION: In this paper, we present the case of a 74-year-old man with a wear debris pseudotumor after TKA with symptoms of severe pain and functional disability of his right knee. X-ray examination showed that the medial compartment of the right knee was narrowing. Magnetic resonance imaging (MRI) and Doppler ultrasound both revealed a polycystic mass at the posteromedial side of the patient's right knee. Considering the bad health condition and the minimally invasive surgery requirement of this senior patient, arthroscopic knee debridement and percutaneous cystic mass suction were carried out simultaneously. Video arthroscopy of the right knee showed visible inflammatory soft tissue, obvious polyethylene fragments, wear of the polyethylene prothesis, and a broken polyethylene insert. The intraarticular polyethylene wear debris was removed as much as possible, and inflammatory soft tissue was debrided and sent for pathology. Postoperative pathology showed polyethylene debris in the soft tissue with an apparent multinucleated giant cell response, which was consistent with foreign body granuloma. All clinical manifestation was improved and Lysholm scores were significantly better at one year with this treatment, increasing from 32 points to 71 points. CONCLUSION: After two years of follow-up, the patient's knee joint was significantly relieved from soreness and pain, and walking was not significantly restricted. Our treatment could not address the root cause of the wear debris pseudotumor, which was due to prosthesis failure, but sometimes, such an approach is the safest, most economical, and most effective choice for patients who are intolerant to reoperation.

Are Damage Modes Related to Microstructure and Material Loss in Severely Damaged CoCrMo Femoral Heads?

BACKGROUND: Fretting and corrosion in metal-on-polyethylene total hip arthoplasty (THA) modular junctions can cause adverse tissue reactions that are responsible for 2% to 5% of revision surgeries. Damage within cobalt-chromium-molybdenum (CoCrMo) alloy femoral heads can progress chemically and mechanically, leading to damage modes such as column damage, imprinting, and uniform fretting damage. At present, it is unclear which of these damage modes are most detrimental and how they may be linked to implant alloy metallurgy. The alloy microstructure exhibits microstructural features such as grain boundaries, hard phases, and segregation bands, which may enable different damage modes, higher material loss, and the potential risk of adverse local tissue reactions. QUESTIONS/PURPOSES: In this study, we asked: (1) How prevalent is chemically dominated column damage compared with mechanically dominated damage modes in severely damaged metal-on-polyethylene THA femoral heads made from wrought CoCrMo alloy? (2) Is material loss greater in femoral heads that underwent column damage? (3) Do material loss and the presence of column damage depend on alloy microstructure as characterized by grain size, hard phase content, and/or banding? METHODS: Surgically retrieved wrought CoCrMo modular femoral heads removed between June 2004 and June 2019 were scored using a modified version of the Goldberg visually based scoring system. Of the total 1002 heads retrieved over this period, 19% (190 of 1002) were identified as severely damaged, exhibiting large areas of fretting scars, black debris, pits, and/or etch marks. Of these, 43% (81 of 190) were excluded for metal-on-metal articulations, alternate designs (such as bipolar, dual-mobility, hemiarthroplasty, metal adaptor sleeves), or previous sectioning of the implant for past studies. One sample was excluded retroactively as metallurgical analysis revealed that it was made of cast alloy, yielding a total of 108 for further analysis. Information on patient age (57 ± 11 years) and sex (56% [61 of 108] were males), reason for removal, implant time in situ (99 ± 78 months), implant manufacturer, head size, and the CoCrMo or titanium-based stem alloy pairing were collected. Damage modes and volumetric material loss within the head tapers were identified using an optical coordinate measuring machine. Samples were categorized by damage mode groups by column damage, imprinting, a combination of column damage and imprinting, or uniform fretting. Metallurgical samples were processed to identify microstructural characteristics of grain size, hard phase content, and banding. Nonparametric Mann-Whitney U and Kruskal-Wallis statistical tests were used to examine volumetric material loss compared with damage mode and microstructural features, and linear regression was performed to correlate patient- and manufacturer-specific factors with volumetric material loss. RESULTS: Chemically driven column damage was seen in 48% (52 of 108) of femoral heads, with 34% (37 of 108) exhibiting a combination of column damage and imprinting, 12% (13 of 108) of heads displaying column damage and uniform fretting, and 2% (2 of 108) exhibiting such widespread column damage that potentially underlying mechanical damage modes could not be verified. Implants with column damage showed greater material loss than those with mechanically driven damage alone, with median (range) values of 1.2 mm3 (0.2 to 11.7) versus 0.6 mm3 (0 to 20.7; p = 0.03). Median (range) volume loss across all femoral heads was 0.9 mm3 (0 to 20.7). Time in situ, contact area, patient age, sex, head size, manufacturer, and stem alloy type were not associated with volumetric material loss. Banding of the alloy microstructure, with a median (range) material loss of 1.1 mm3 (0 to 20.7), was associated with five times higher material loss compared with those with a homogeneous microstructure, which had a volume loss of 0.2 mm3 (0 to 4.1; p = 0.02). Hard phase content and grain size showed no correlation with material loss. CONCLUSION: Chemically dominated column damage was a clear indicator of greater volume loss in this study sample of 108 severely damaged heads. Volumetric material loss strongly depended on banding (microstructural segregations) within the alloy. Banding of the wrought CoCrMo microstructure should be avoided during the manufacturing process to reduce volumetric material loss and the release of corrosion products to the periprosthetic tissue. CLINICAL RELEVANCE: Approximately 30% of THAs rely on wrought CoCrMo femoral heads. Most femoral heads in this study exhibited a banded microstructure that was associated with larger material loss and the occurrence of chemically dominated column damage. This study suggests that elimination of banding from the alloy could substantially reduce the release of implant debris in vivo, which could potentially also reduce the risk of adverse local tissue reactions to implant debris.

In vitro modeling accurately predicts cardiac lead fracture at 10 years.

BACKGROUND: Development of a cardiac lead fracture model has the potential to differentiate well-performing lead designs from poor performing ones and could aid in future lead development. OBJECTIVE: The purpose of this study was to demonstrate a predictive model for lead fracture and validate the results generated by the model by comparing them to observed 10-year implantable cardioverter-defibrillator lead fracture-free survival. METHODS: The model presented here uses a combination of in vivo patient data, in vitro conductor fatigue test data, and statistical simulation to predict the fracture-free survival of cardiac leads. The model was validated by comparing the results to human clinical performance data from the Medtronic Sprint Fidelis (Minneapolis, MN) models 6931 (single coil, active fixation) and 6949 (dual coil, active fixation), as well as the Quattro model 6947 (dual coil, active fixation). RESULTS: Median patient age in the single coil Fidelis 6931 population (64 years) was less than in the dual coil Fidelis 6949 and Quattro populations (68 years). Modeled and observed fracture-free survival for Quattro (>97%) was superior to that for Fidelis (<94%). The modeled survival agreed with the observed fracture-free survival data. The average model error was 0.3% (SD 1.2%). CONCLUSION: This model for cardiac lead fracture-free survival using in vivo lead bending measurements and in vitro bench testing can be used to predict lead performance as observed by alignment with field survival data.

Radiographic assessment of radiolucent lines around a highly porous titanium cup (Tritanium) using digital tomosynthesis, after total hip arthroplasty.

BACKGROUND: The objectives of this study were to assess radiolucent lines around a highly porous titanium cup (Tritanium) using digital tomosynthesis and to investigate the clinical and radiographic factors associated with radiolucent lines on tomosynthesis. METHODS: Fifty-five patients underwent total hip arthroplasty using a Tritanium cup, and digital tomosynthesis and plain radiography were performed at 1 week, 6 months, 1 year, and 2 years after surgery. The radiolucent lines around the cup were measured on both DTS and plain radiography at each postoperative period. Clinical evaluations were performed by the Japanese Orthopaedic Association hip disease evaluation questionnaire (JHEQ), and revision surgeries were examined. Based on the presence of radiolucent lines on digital tomosynthesis at 2 years postoperatively, patients were divided into RL (+) and RL (-) groups and investigated for related factors. RESULTS: There were 20 cases in the RL (+) group and 35 cases in the RL (-) group, and no revision surgeries were required. Statistically, there were more cases with radiolucent lines on digital tomosynthesis (45.4% at 1 week and 36.3% at 2 years) than on plain radiography (9.1% at 1 week and 9.1% at 2 years) at each postoperative point. Logistic analysis showed no significant associations between the presence of radiolucent lines at 2 years on digital tomosynthesis, and the JHEQ parameters of pain (p = 0.937), movement (p = 0.266), or mental status (p = 0.404). CONCLUSION: In a short-term evaluation up to 2 years, digital tomosynthesis detected more radiolucent lines around the titanium cups than plain radiography. The occurrence of radiolucent lines was not related to the postoperative clinical evaluation.