Metal-on-metal (MoM) hip implants and pregnancy: are MoM implants good for mom?-a systematic review.

Metal-on-metal (MoM) bearing surfaces were historically used for young patients undergoing total hip arthroplasty (THA), and remain commonplace in modern hip resurfacing. A substantial number of female patients with MoM bearings subsequently gave birth following implantation of the bearings before a full understanding of metal ions exposure in these patients was established. In theory, it has been postulated that metal ions released from such implants may cross the placental barrier and cause harm to the fetus. In light of this potential risk, recommendations against the use of MoM components in women of child-bearing age have been advocated. The purpose of this systematic review was to evaluate: (I) the MoM bearing types and ion levels found; (II) the concentrations of metals in maternal circulation and the umbilical cord; and (III) the presence of abnormalities in the fetus or delivered child. A comprehensive literature review was conducted of studies published between January 1st, 1975 and April 1st, 2019 using specific keywords. We defined the inclusion criteria for qualifying studies for this review as follows: (I) studies that reported on the women who experienced pregnancy and who had a MoM hip implant; (II) studies that reported on maternal metal ions blood and umbilical cord levels; and (III) studies that reported on the occurrence of fetal complications. Data on cobalt and chromium ion levels in the maternal blood and umbilical cord blood, as well as the presence of adverse effects in the infant were collected. Age at parturition and time from MoM implant to parturition were also collected. A total of six studies were included in the final analysis that reported on a total of 21 females and 21 infants born. The mean age at parturition was 31 years (range, 24 to 41 years), and the mean time from MoM implantation to parturition was 47 months (range, 11 to 119 months). Maternal blood cobalt levels were found as a weighted average of 34.09 µg/L (0.425 to 138 µg/L), while umbilical cord blood cobalt levels were found to be 22.61 µg/L (0.52 to 51.11 µg/L). Cobalt levels were reduced by an average of 34% between maternal and umbilical cord blood. Maternal cord blood chromium levels were found as a weighted average of 18.18 µg/L (0.225 to 75 µg/L), while umbilical cord chromium levels were found to be 3.96 µg/L (0.14 to 11.96 µg/L). Chromium levels were reduced by an average of 78% between maternal and umbilical cord blood. No cobalt or chromium was detected in the umbilical cord blood of three patients. Out of the 21 infants born to women with MoM implants, 20 were born healthy with no adverse effects or complications. Only one complication was recorded in single infant that did not appear to be related to the maternal MoM implant. To date, there is a lack of consensus as to whether MoM hip arthroplasty implants are to be avoided in the child-bearing female population and whether they constitute a hazard to the fetus in utero. Both chromium and cobalt ions were markedly reduced in levels when transitioning from maternal to cord blood. In particular, chromium showed a greater reduction on average than cobalt (78% vs. 34%). Based on the current evidence, there appears to be no correlation between the presence of metal ions in umbilical cord blood and complications, as none of the infants experienced abnormalities uniquely attributable to the presence of metal ions.

The international normalised ratio predicts perioperative complications in revision total hip arthroplasty.

BACKGROUND: Standard preoperative protocols in total joint arthroplasty utilise the international normalised ratio (INR) to determine patient coagulation profiles. However, the relevance of preoperative INR values in joint arthroplasty remains controversial. Therefore, we examined (1) the relationship between preoperative INR values and various outcome measures, including, but not limited to: surgical site complications, medical complications, bleeding, number of readmissions, and mortality. Additionally, we sought to determine (2) specific INR values associated with these complications and (3) cutoff INR levels which correlated with specific outcomes. We additionally applied these analyses to (4) examine the relationship between INR and length-of-stay (LOS). METHODS: The American College of Surgeons National Surgical Quality Improvement Program database (ACS-NSQIP) was queried for rTHA procedures performed between 2006 and 2017. INR ranges were used to stratify cohorts: ⩽1.0, 1.0-⩽1.25, 1.25-⩽1.5, >1.5. INR values were determined using receiver operating characteristics (ROC) curves for each outcome of interest. Optimal cutoff INR values for each outcome were then obtained using univariate/multivariate models. 2012 patients who underwent rTHA met inclusion criteria. RESULTS: Patients with progressively higher INR values had a significantly different risk of mortality within 30 days (p = 0.005), bleeding requiring transfusion (p < 0.001), sepsis (p = 0.002), stroke (p < 0.001), failure to wean from ventilator within 48 hours (p = 0.001), readmission (p = 0.01), and hospital length of stay (p < 0.001). Similar results were obtained when utilising optimal INR cutoff values. When correcting for other factors, the following poor outcomes were significantly associated with the respective INR cutoff values (Estimate, 95% CI, p-value): LOS >4 days (1.67, 1.34-2.08, p < 0.001), bleeding requiring transfusion (1.65, 1.30-2.09, p < 0.001), sepsis (2.15, 1.11-4.17, p = 0.022), and any infection (1.82, 1.01-3.29, p = 0.044). CONCLUSIONS: Our analysis illustrates a direct relationship between specific preoperative INR levels and poor outcomes following rTHA, including increased LOS, transfusion requirements and infection. Therefore, current INR guideline targets may need to be re-examined when optimising patients for revision arthroplasty.

Machine Learning Algorithms Identify Optimal Sagittal Component Position in Total Knee Arthroplasty.

BACKGROUND: Advanced technologies, like robotics, provide enhanced precision for implanting total knee arthroplasty (TKA) components; however, the optimal targets for implant position specifically in the sagittal plane do not exist. This study identified sagittal implant position which may predict improved outcomes using machine learning algorithms. METHODS: A retrospective review of 1091 consecutive TKAs was performed. All TKAs were posterior cruciate ligament retaining or sacrificing with an anterior-lip (49.4%) or conforming bearing (50.6%) and performed with modern perioperative protocols. Preoperative and postoperative tibial slope and postoperative femoral component flexion were measured with standardized radiographic protocols. Analysis groups were categorized by satisfaction scores and the Knee Society Score question 'does this knee feel normal to you?' Machine learning algorithms were used to identify optimal sagittal alignment zones that predict superior satisfaction and knees "always feeling normal" scores. RESULTS: Mean age and median body mass index were 66 years and 34 kg/m2, respectively, with 67% being female. The machine learning model predicted an increased likelihood of being "satisfied or very satisfied" and a knee "always feeling normal" with a change in tibial slope closer to native (-2 to +2°) and femoral component flexion 0 to +7°. Worse outcomes were predicted with any femoral component extension, femoral component flexion beyond +10°, and adding or removing >5° of native tibial slope. CONCLUSION: Superior patient-reported outcomes were predicted with approximating native tibial slope and incorporating some femoral component flexion. Deviation from native tibial slope and excessive femoral flexion or any femoral component extension were predictive of worse outcomes. LEVEL OF EVIDENCE: Therapeutic level III.

Selective Embolization Is Safe and Effective for Total Knee Arthroplasty-Associated Recurrent Hemarthroses: A Systematic Review and Meta-Analysis.

Total knee arthroplasty (TKA)-associated hemarthroses are infrequent and often respond to nonoperative therapy. Geniculate artery embolization may provide symptomatic relief in cases recalcitrant to needle aspiration, although no meta-analysis exists regarding this therapy. This meta-analysis aims to assess the rate of symptom relief, the number of embolizations needed to achieve relief, and the rate of complications associated with embolization. Public databases were queried from 1998 until 2018 for TKA-associated recurrent hemarthroses treated with embolization. Eight studies met inclusion and exclusion criteria. Major complications were defined as those requiring readmission or nonelective reoperation; minor complications were defined as those not requiring readmission or reoperation. Pooled statistics were calculated utilizing the method of inverse variance. Fifty-nine patients with a mean follow-up of 30 months (range, 1-50 months) were evaluated. The pooled proportion of patients with symptom improvement following embolization was 86% (95% confidence interval [CI]: 74-93%, I 2: 0%, p = 0.97). The average number of embolization procedures was 1.30 (95% CI: 1.03-1.63, I 2: 0%, p = 0.66). The pooled proportion of patients who required a second embolization procedure was 26% (95% CI: 15-40%, I 2: 0%, p = 0.43), while those requiring three or more procedures was 13% (95% CI: 6-25%, I 2: 0%, p = 0.87). The rate of complications were as follows: any complication - 19% (95% CI: 11-32%, I 2: 0%, p = 0.81); major complications-8% (95% CI: 3-19%, I 2: 0%, p = 0.96); minor complications-18% (95% CI: 10-31%, I 2: 0%, p = 0.79); inguinal hematoma-9% (95% CI: 4-19%, I 2: 0%, p = 1.00); skin necrosis-15% (95% CI: 7-29%, I 2: 0%, p = 0.62); and incision breakdown-7% (95% CI: 3-17%, I 2: 0%, p = 1.00). Previous literature on selective artery embolization following TKA is relatively limited. This meta-analysis supports embolization as a potentially safe and effective treatment for recurrent hemarthroses after TKA. Other correctable causes of recurrent hemarthrosis, such as instability or malalignment, must be diligently ruled out prior to utilizing embolization. Surgeons should be aware of embolization's potential role in the postoperative period following TKA.

What Are Risk Factors for Infection after Primary or Revision Total Joint Arthroplasty in Patients Older Than 80 Years?

BACKGROUND: Patients older than 80 years of age form an increasing proportion of the patient population undergoing total joint arthroplasty (TJA). With increasing life expectancy and the success of TJA, orthopaedic surgeons are more likely to operate on patients older than 80 years than ever before. Given that most other studies focus on younger populations, only evaluate primary TJA, or limit patient populations to institutional or regional data, we felt a large-database, nationwide analysis of this demographic cohort was warranted, and we wished to consider both primary and revision TJA. QUESTIONS/PURPOSES: In this study, we sought to investigate the risk factors for surgical site infections (SSIs) at 90 days and periprosthetic joint infections (PJIs) at 2 years after surgery in patients aged 80 years and older undergoing (1) primary and (2) revision lower extremity TJA. METHODS: All patients aged 80 years or older who underwent primary or revision TJA between 2005 and 2014 were identified using the Medicare Analytical Files of the PearlDiver Supercomputer using ICD-9 codes. This database is unique in that it is one of the largest nationwide databases, and so it provides a large enough sample size of patients 80 years or older. Additionally, this database provides comprehensive and longitudinal patient data tracking, and a low error rate. Our final cohort consisted of 503,241 patients (TKA: n = 275,717; THA: n = 162,489; revision TKA: n = 28,779; revision THA: n = 36,256). Multivariate logistic regression models were constructed to evaluate the association of risk factors on the incidences of 90-day SSI and 2-year PJI. Variables such as sex, diabetes, BMI, and congestive heart failure, were included in the multivariate regression models. Several high-risk comorbidities as identified by the Charlson and Elixhauser comorbidity indices were selected to construct the models. We performed a Bonferroni-adjusted correction to account for the fact that multiple statistical comparisons were made, with a p value < 0.002 being considered statistically significant. RESULTS: For primary TKA patients, an increased risk of 90-day SSIs was associated with male sex (OR 1.28 [95% CI 1.25 to 1.52]; p < 0.001), BMI greater than 25 k/m (p < 0.001), and other comorbidities. For primary THA patients, an increased risk of 90-day SSIs was associated with patients with obesity (BMI 30-39 kg/m; OR 1.91 [95% CI 1.60 to 2.26]; p < 0.001) and those with morbid obesity (BMI 40-70 kg/m; OR 2.58 [95% CI 1.95 to 3.36]; p < 0.001). For revision TKA patients, an increased risk of SSI was associated with iron-deficiency anemia (OR 1.82 [95% CI 1.37 to 2.28]; p < 0.001). For revision THA patients, electrolyte imbalance (OR 1.48 [95% CI 1.23 to 1.79]; p < 0.001) and iron-deficiency anemia (OR 1.63 [95% CI 1.35 to 1.99]; p < 0.001) were associated with an increased risk of 90-day SSI. Similar associations were noted for PJI in each cohort. CONCLUSIONS: These findings show that in this population, male sex, obesity, hypertension, iron-deficiency anemia, among other high-risk comorbidities are associated with a higher risk of SSIs and PJIs. Based on these findings, orthopaedic surgeons should actively engage in comanagement strategies with internists and other specialists to address modifiable risk factors through practices such as weight management programs, blood pressure reduction, and electrolyte balancing. Furthermore, this data should encourage healthcare systems and policy makers to recognize that this patient demographic is at increased risks for PJI or SSI, and these risks must be considered when negotiating payment bundles. LEVEL OF EVIDENCE: Level III, therapeutic study.

Are We Treating Similar Patients? Hospital Volume and the Difference in Patient Populations for Total Knee Arthroplasty.

BACKGROUND: Early findings of superior total knee arthroplasty (TKA) outcomes at high volume centers have been thought to have led to distinct referral patterns. However, the effect of these selective referral processes has not been well assessed. Therefore, this study compared the characteristics of primary TKA patients at high, intermediate, and low volume hospitals. METHODS: A total of 12,541 primary TKA patients were stratified into risk groups based on age (>65 years), body mass index (>40), and Charlson Comorbidity Index (≥4). Hospitals were classified as low, intermediate, or high volume based on mean annual TKA volumes (<250, 250-499, and >500). Multivariate logistic regression models evaluated the relationship between baseline patient characteristics and hospital volume. RESULTS: There was a greater percentage of high risk patients at high volume (19%, n = 853) compared to those at intermediate (16%, n = 899) or low volume (17%, n = 444) hospitals (P < .001). Patients with a body mass index >40 were more likely to be treated at high compared to intermediate (odds ratio [OR] 1.4, 95% confidence interval [CI] 1.2-1.6, P < .001) and low volume centers (OR 1.4, 95% CI 1.2-1.7, P < .001). Patients with Charlson Comorbidity Index scores ≥4 were also more likely be treated at high compared to intermediate (OR 1.5, 95% CI 1.3-1.6, P < .001) or low (OR 1.2, 95% CI 1.0-1.4, P = .002) volume centers. CONCLUSION: This study found that TKA patients at high volume centers have significantly different baseline characteristics compared to those at lower volume centers. This study highlights the importance of considering hospital volume status and the associated disparity in the preoperative risk of patients when comparing primary TKA outcomes between centers.

A Prospective Analysis of Motor and Cognitive Skill Retention in Novice Learners of Point of Care Ultrasound.

OBJECTIVES: To identify the time at which point of care ultrasound static image recognition and image acquisition skills decay in novice learners. SETTING: The University of Iowa Hospitals and Clinics. SUBJECTS: Twenty-four subjects (23 first-year medical students and one first-year physician assistant student). DESIGN: The subjects completed an initial didactic and hands-on session with immediate testing of learned image acquisition and static image identification skills. INTERVENTIONS: Retesting occurred at 1, 4, and 8 weeks after the initial training session with no retraining in between. Image acquisition skills were obtained on the same healthy male volunteers, and the students were given no immediate feedback on their performance. The image identification skills were assessed with a 10 question test at each follow-up session. MEASUREMENTS AND MAIN RESULTS: For pleural ultrasound by 4 weeks, there was a significant decline of the ability to identify A-lines (p = 0.0065). For pleural image acquisition, there was no significant decline in the ability to demonstrate lung sliding. Conversely, cardiac image recognition did not significantly decline throughout the study, while the ability to demonstrate cardiac images at 4 weeks (parasternal short axis view) did (p = 0.0008). CONCLUSIONS: Motor and cognitive skills decay at different times for pleural and cardiac images. Future ultrasound curricula should retrain skills at a maximum of 8 weeks from initial training. They should focus more on didactic sessions related to image identification for pleural images, and more hands-on image acquisition training for cardiac images, which represents a novel finding.

Do neoprene sleeves and prophylactic knee braces affect neuromuscular control and cutting agility?

OBJECTIVES: To evaluate the effects of neoprene sleeves (NSs) and prophylactic knee braces (PKBs) on neuromuscular control and cutting agility. DESIGN: Markerless motion-capture technology tracked subjects (1) without a brace as a control (2) with NSs and (3) with PKBs during single-leg drop vertical jump (SLDVJ), single-leg squat (SLS), Y-excursion, and cutting movements. Movements were recorded five times per bracing condition in three different sessions. SETTING: University laboratory. PARTICIPANTS: Ten healthy, active subjects (5 male, 5 female; age range, 22-26 years). MAIN OUTCOME MEASURES: Degrees of motion and time to completion. RESULTS: Use of NSs and PKBs reduced subjects' hip internal rotation in the loading phase of SLDVJ (p = 0.026, 0.02) and SLS (p = 0.005, <0.001), reduced knee flexion in the loading phase of SLDVJ (p = 0.038, <0.001), and reduced knee frontal plane abduction (FPA) with SLS (p = 0.015, 0.024) and Y-excursion (p = 0.002, 0.005) compared to control. Use of PKBs decreased subjects' hip internal rotation in the Y-excursion (p = 0.024) and reduced knee FPA in the SLDVJ loading phase (p = 0.014) compared to control. There was no difference in cutting agility for either group (p = 0.145, 0.347). CONCLUSION: Both NSs and PKBs positively impacted neuromuscular control without impacting cutting agility.