Imaging in revision total knee arthroplasty: A novel 3D classification system for tibial bone defects.

PURPOSE: The primary purpose of the study was to use pre-revision total knee arthroplasty (TKA) computer-tomography (CT)-images to analyse typical tibial bone defects and create a new schematic three-dimensional (3D)-classification system. The secondary purpose was to investigate the association between defect size and implant selection at the time of revision surgery. METHODS: Eighty-four patients with preoperative CT-scans underwent revision of a primary TKA. CT-image segmentation with the 3D-Slicer Software was performed retrospectively, and a new three-dimensional classification system was used to grade tibial bone defects. The location of tibial bone defects was recorded for all cases. Volumetric 3D bone defect measurements were used to investigate the association between the bone defect volume, the indication for rTKA, and the use of modular revision components. The t-test, the Mann-Whitney-U test, and the Fisher's exact-test were used for group comparisons, and the Kruskal-Wallis test was used for multiple group comparisons. RESULTS: The most common anatomic regions for both contained and uncontained tibial bone defects were the anteromedial epiphysis (N = 50; mean epiphyseal-defect: 5.9 cm³) and metaphysis (N = 15; mean metaphyseal-defect: 9.6 cm³). A significant association was found between patients with preoperative metaphyseal defects (N = 22) and the use of tibial augments (N = 7) (p = 0.04). The use of cones/sleeves was associated with a significantly increased 3D-CT volume of the preoperative metaphyseal bone defects (p = 0.04). Patients with osteoporosis had significantly larger volumetric defects in the metaphysis (p = 0.01). CONCLUSION: Our results emphasise the importance of considering the three-dimensional nature of tibial defects in rTKA. The findings suggest that an understanding of the volume of the defect size through CT imaging can predict the need for augments and cones/sleeves and, especially in patients with osteoporosis can help the surgeon identify larger metaphyseal defects and ensure optimal metaphyseal fixation through appropriate implant selection. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

The Surgical Approach Impacts Component Selection in Total Hip Arthroplasty: A Matched Cohort Study of 7,460 Hips.

BACKGROUND: A higher risk of dislocation following total hip arthroplasty (THA) has been reported for the posterior approach (PA) compared to the anterior approach (AA). Dual mobility implants, larger head sizes, and elevated or face-changing liners can reduce the risk for dislocation. It remains unclear whether the component selection is influenced by the surgical approach. METHODS: This is a retrospective study of 7,048 patients who underwent 7,460 primary THA with either AA or PA for primary hip osteoarthritis or osteonecrosis of the femoral head between 2019 and 2021. A propensity score model based on age, body mass index, height, and American Association of Anesthesiologists Score was applied. There were 2,502 AA-THA matched with 4,958 PA-THA (2,456 1:2, and 46 1:1). Groups were compared with multiple linear regression analyses/multivariate logistic regressions after controlling for American Association of Anesthesiologists Score and body mass index. In a second step, only hips operated by surgeons using both approaches were matched 1:1 (1,204 PA and AA, respectively). The same statistics were performed after controlling for "surgeon". RESULTS: The PA was associated with a more frequent use of dual mobility implants, elevated liners, face-changing liners, as well as heads with 36 mm or larger diameters, and the implanted cups were significantly larger (P < .001, respectively). These findings were consistent for both matched cohorts. CONCLUSION: The surgical approach impacts the component selection in THA. Patients undergoing PA-THA are more likely to receive implants with larger head size or stabilizing features compared to AA-THA.

There is No Increased Pulmonary Risk Following Total Hip Arthroplasty in Patients Who Have Obstructive Sleep Apnea Without Underlying Lung Disease.

BACKGROUND: Obstructive sleep apnea (OSA) is a frequent comorbidity. The current study evaluated whether there is a difference in the perioperative outcome after total hip arthroplasty (THA) in patients who had a low to moderate risk for OSA and high risk for OSA, respectively. METHODS: After excluding patients who had concomitant lung disease (chronic obstructive pulmonary disease, asthma, or lung fibrosis) and those missing a STOP-Bang Score, 1,141 THA patients who had OSA were included in this retrospective study. Patients at low to moderate risk for OSA (STOP-Bang Score 0 to 4) and patients at high risk for OSA (STOP-Bang Score 5 to 8) were compared, and SpO2 (oxygen saturation) drops < 90% as well as readmission rates were compared between patients who did and did not use continuous positive airway pressure (CPAP). RESULTS: There was no difference in the risk of SpO2 drop below 90% (1 versus 0%, P = 0.398) and readmission rate (2 versus 2%, P = 0.662) between patients who had low to moderate OSA risk (327 THA) and high OSA risk (814 THAs). There was no difference in SpO2 (P > 0.999) and a decrease in oxygen flow rate from the postanesthesia care unit to the morning of the first postoperative day. A CPAP device was used by 41% (467 of 1,141) of patients. There were no differences in SpO2 drop < 90% (0 versus 0%, P = 0.731) and readmission rate (2 versus 2%, P = 0.612) between patients who did and did not use a CPAP machine. CONCLUSIONS: The current study showed no difference in perioperative outcomes between OSA patients undergoing THA who had a low STOP-Bang Score and patients who had a high STOP-Bang Score, regardless of the use of a CPAP machine. These data suggest that an elevated Stop-Bang Score does not indicate an increased perioperative risk for OSA patients when deciding on outpatient discharge.

Reconstruction of Chronic Quadriceps Tendon Rupture: The Quadriceps Advancement and Imbrication Technique.

BACKGROUND: Chronic extensor mechanism disruption after total knee arthroplasty (TKA) is a rare but challenging condition. There are several surgical approaches for quadriceps tendon repairs. In this report, we present a modified surgical technique for quadriceps tendon repair in chronic extensor mechanism disruption without the use of allografts or mesh augmentation. METHODS: We retrospectively reviewed 12 consecutive cases of chronic extensor mechanism with complete quadriceps tendon ruptures after TKA that underwent the advancement and imbrication technique. Patient outcomes were evaluated using the Knee Injury and Osteoarthritis Outcome Score for Joint Replacement, the range of motion and extensor lag measurements, and standardized lateral radiographs were reviewed for Insall-Salvati-Ratio preoperatively and at their most recent follow-up visit. RESULTS: There were 12 knees from patients who had a mean age of 72 years (range, 62 to 81) and were evaluated with a mean follow-up of 15.9 months (range, 11.4 to 50.9). The extensor lag significantly improved from 40.8 ± 31.9° (range, 10 to 90°) to 2.9 ± 6.9° (P = .014), the Insall-Salvati-Ratio significantly changed from 0.87 to 1.07 (P = .010), and the Knee Injury and Osteoarthritis Outcome Score for Joint Replacement showed a significant difference: a raw score of 13.0 ± 5.8 versus 8.7 ± 5.6 (P = .002) and an interval score of 54.1 ± 14.0 versus 66.2 ± 15.6 (P = .001). CONCLUSIONS: Reconstruction of extensor mechanism in chronic quadriceps tendon ruptures after TKA with the advancement and imbrication technique showed excellent functional outcomes with no extensor lag and excellent restoration of motion. This technique can be combined with TKA revision surgery or used on its own. To ensure successful outcomes, the authors favor rigid immobilization for 12 weeks before starting mobilization.

Complex periprosthetic wound coverage in patients undergoing revision total knee arthroplasty: a single plastic surgeon study.

INTRODUCTION: Options for soft tissue coverage in revision total knee arthroplasty (rTKA) range from primary wound closure to complex muscle flap reconstructions. The purpose of this study was to investigate the institutional experience of wound coverage options for complex soft tissue defects in rTKA. MATERIALS AND METHODS: 77 patients undergoing rTKA with complex wound closure by a single plastic surgeon were retrospectively reviewed. The average follow-up was 30.1 months. In 18 (23.4%) patients, an intraoperative decision for primary closure was made. Fifty-nine patients (76.6%) received either a local fasciocutaneous (N = 18), a medial gastrocnemius (N = 37), a free latissimus dorsi (N = 3) or a lateral gastrocnemius flap (N = 1). Revision-free survival and complication rates were assessed and risk factors were analyzed with Cox-regression analysis. RESULTS: Medial gastrocnemius flaps had significant lower cumulative revision-free survival rates than local fasciocutaneous flaps (P = 0.021) and primary closures (P < 0.001) (42.5% vs. 71.5% vs. 100%,respectively). Comparing the most common complex closure procedures medial gastrocnemius flaps had the highest rate of prolonged wound healing (29.7%) and infection/reinfection (40.5%). Infection-associated flap procedures had significant lower cumulative revision-free survival rates (30.5%) than non-infection associated flap procedures (62.8%,P = 0.047). A history of more than two prior surgeries (HR = 6.11,P < 0.001) and an age ≥ 65 years (HR = 0.30,P = 0.018) significantly increased the risk of revision. CONCLUSIONS: The results of this study indicate that primary closure -if possible- should be preferred to early proactive muscle flap coverage. Even in the hands of an experienced plastic surgeon muscle flaps have high revision and complication rates. The study highlights the need to clarify flap indications and to investigate alternative approaches.

Reliability and validity of the Paprosky classification for acetabular bone loss based on level of orthopedic training.

BACKGROUND: Reliability and validity of the Paprosky classification for acetabular bone loss have been debated. Additionally, the relationship between surgeon training level and Paprosky classification accuracy/treatment selection is poorly defined. This study aimed to: (1) evaluate the validity of preoperative Paprosky classification/treatment selection compared to intraoperative classification/treatment selection and (2) evaluate the relationship between training level and intra-rater and inter-rater reliability of preoperative classification and treatment choice. METHODS: Seventy-four patients with intraoperative Paprosky types [I (N = 24), II (N = 27), III (N = 23)] were selected. Six raters (Residents (N = 2), Fellows (N = 2), Attendings (N = 2)) independently provided Paprosky classification and treatment using preoperative radiographs. Graders reviewed images twice, 14 days apart. Cohen's Kappa was calculated for (1) inter-rater agreement of Paprosky classification/treatment by training level (2), intra-rater reliability, (3) preoperative and intraoperative classification agreement, and (4) preoperative treatment selection and actual treatment performed. RESULTS: Inter-rater agreement between raters of the same training level was moderate (K range = 0.42-0.50), and mostly poor for treatment selection (K range = 0.02-0.44). Intra-rater agreement ranged from fair to good (K range = 0.40-0.73). Agreement between preoperative and intraoperative classifications was fair (K range = 0.25-0.36). Agreement between preoperative treatment selections and actual treatments was fair (K range = 0.21-0.39). CONCLUSION: Inter-rater reliability of Paprosky classification was poor to moderate for all training levels. Preoperative Paprosky classification showed fair agreement with intraoperative Paprosky grading. Treatment selections based on preoperative radiographs had fair agreement with actual treatments. Further research should investigate the role of advanced imaging and alternative classifications in evaluation of acetabular bone loss.

How safe are intra-articular corticosteroid injections to the hip?

BACKGROUND: Intra-articular corticosteroid injections (ICSI) are an effective symptomatic treatment for osteoarthritis of the hip. However, the safety of ICSI has been questioned and a relatively high risk for septic arthritis, rapidly progressive osteoarthritis (RPIO) and periprosthetic joint infections (PJI) in patients undergoing subsequent total hip arthroplasty (THA) have been suggested. METHODS: This is a retrospective evaluation of 682 hips that underwent ICSI with 40 mg of Triamcinolone for primary osteoarthritis of the hip. All ICSI were performed using sterile techniques, the number of ICSI in each hip and the cumulative corticosteroid dosage were assessed. Pre- and post-injection radiographs were compared to identify cases with RPIO. Native joint septic arthritis, surgical site infections and PJI were identified by chart review. RESULTS: 4 hips (0.6%) developed RPIO 2-4 months following ICSI. The cumulative Triamcinolone dose was not associated with the development of RPIO (p = 0.281). 1 case was diagnosed with septic arthritis and treated with staged THA, there were no signs of infection at a 5 years follow-up. 483 hips (75.7%) underwent THA, including 199 hips with THA less than 3 months following ICSI and 181 hips with > 1 ICSI prior to THA. There were 3 superficial surgical site infections/wound dehiscence and no PJI. CONCLUSION: The rate of RPIO was 0.6%. The current findings suggest that if ICSI is performed under sterile conditions, the risk for septic arthritis or PJI following THA, even in patients with multiple ICSI or ICSI within 3 months prior to surgery, is minimal.

Tibial bone defect prediction based on preoperative artefact-reduced CT imaging is superior to standard radiograph assessment.

PURPOSE: The purpose of this study was to evaluate the accuracy of preoperative CT-based Anderson Orthopaedic Research Institute (AORI)-grading and to correlate Computed tomography (CT)-based volumetric defect measurements with intraoperative AORI findings. METHODS: 99 patients undergoing revision total knee arthroplasty (rTKA) with preoperative CT-images were identified in an institutional revision registry. CT-image segmentation with 3D-Slicer Software was used to create 3D tibial bone defects which were then graded according to the AORI-classification. The AORI classification categorizes tibial defects into three types: Type I has healthy cortical and cancellous bone near the joint line, Type II involves metaphyseal bone loss affecting one or both condyles, and Type III indicates deficient metaphyseal bone with distal defects and potential damage to the patellar tendon and collateral ligament attachments. These 3D-CT gradings were compared to preoperative X-ray and intraoperative AORI grading. The Friedman test was used to investigate differences between AORI values of each measurement method. Volumetric 3D-bone defect measurements were used to investigate the relationship between AORI classification and volumetric defect size in the three anatomic zones of the tibia. RESULTS: Substantial agreements between preoperative 3D-CT AORI and intraoperative AORI (kappa = 0.663; P < 0.01) and fair agreements between preoperative X-ray AORI and intraoperative AORI grading (kappa = 0.304; P < 0.01) were found. Moderate correlations between volume of remaining bone and intraoperative AORI grading were found in epiphysis (rS = - 0.529; P < 0.001), metaphysis (rS = - 0.557; P < 0.001) and diaphysis (rS = - 0.421; P < 0.001). Small volumetric differences between AORI I vs. AORI II defects and relatively large differences between AORI II and AORI III defects in each zone were detected. CONCLUSION: Tibial bone defect prediction based on preoperative 3D-CT segmentation showed a substantial agreement with intraoperative findings and is superior to standard radiograph assessment. The relatively small difference in defect volume between AORI I, IIa and IIb suggests that updated CT-based classifications might hold benefits for the planning of rTKA. LEVEL OF EVIDENCE: Retrospective Cohort Study; III.

Standardized Fixation Zones and Cone Assessments for Revision Total Knee Arthroplasty Using Deep Learning.

BACKGROUND: Achieving adequate implant fixation is critical to optimize survivorship and postoperative outcomes after revision total knee arthroplasty (rTKA). Three anatomical zones (ie, epiphysis, metaphysis, and diaphysis) have been proposed to assess fixation, but are not well-defined. The purpose of the study was to develop a deep learning workflow capable of automatically delineating rTKA zones and cone placements in a standardized way on postoperative radiographs. METHODS: A total of 235 patients who underwent rTKA were randomly partitioned (6:2:2 training, validation, and testing split), and a U-Net segmentation workflow was developed to delineate rTKA fixation zones and assess revision cone placement on anteroposterior radiographs. Algorithm performance for zone delineation and cone placement were compared against ground truths from a fellowship-trained arthroplasty surgeon using the dice segmentation coefficient and accuracy metrics. RESULTS: On the testing cohort, the algorithm defined zones in 98% of images (8 seconds/image) using anatomical landmarks. The dice segmentation coefficient between the model and surgeon was 0.89 ± 0.08 (interquartile range [IQR]:0.88-0.94) for femoral zones, 0.91 ± 0.08 (IQR: 0.91-0.95) for tibial zones, and 0.90 ± 0.05 (IQR:0.88-0.94) for all zones. Cone identification and zonal cone placement accuracy were 98% and 96%, respectively, for the femur and 96% and 89%, respectively, for the tibia. CONCLUSION: A deep learning algorithm was developed to automatically delineate revision zones and cone placements on postoperative rTKA radiographs in an objective, standardized manner. The performance of the algorithm was validated against a trained surgeon, suggesting that the algorithm demonstrated excellent predictive capabilities in accordance with relevant anatomical landmarks used by arthroplasty surgeons in practice.

Does high activity after total and unicompartmental knee arthroplasty increase the risk for aseptic revision?

INTRODUCTION: It has been suggested that high activity might negatively impact implant survival following total and unicompartmental knee arthroplasty (TKA/UKA) and many surgeons advise their patients to only participate in moderate level sport activities. To date, it remains unclear whether such restraints are necessary to assure longevity of the implants. MATERIALS AND METHODS: We conducted a retrospective study on 1906 knees (1745 TKA, 161 UKA) in 1636 patients aged 45-75 years who underwent primary arthroplasty for primary osteoarthritis. Lower extremity activity scale (LEAS) at a two year follow-up was assessed to define the activity level. Cases were grouped in low (LEAS ≤ 6), moderate (LEAS 7-13) and high activity (LEAS ≥ 14). Cohorts were compared with Kruskal-Wallis- or Pearson-Chi2-Test. Univariate logistic regression was conducted to test for association between activity level at two years and later revisions. Odds ratio was reported and converted to predicted probability. A Kaplan-Meier curve was plotted to predict implant survival. RESULTS: The predicted implant survival for UKA was 100.0% at two years and 98.1% at five years. The predicted implant survival for TKA was 99.8% at two years, 98.1% at five years. The difference was not significant (p = 0.410). 2.5% of the UKA underwent revision, one knee in the low and three knees in the moderate activity group, differences between the moderate and high activity group were not significant (p = 0.292). The revision rate in the high activity TKA group was lower than in the low and moderate activity groups (p = 0.008). A higher LEAS two years after surgery was associated with a lower risk for future revision (p = 0.001). A one-point increase in LEAS two years after surgery lowered the odds for undergoing revision surgery by 19%. CONCLUSIONS: The study suggests that participating in sports activity following both UKA and TKA is safe and not a risk factor for revision surgery at a mid-term follow-up. Patients should not be prevented from an active lifestyle following knee replacement.

Predictors for activity following total and unicompartmental knee arthroplasty.

BACKGROUND: Functional demands of patients undergoing knee arthroplasty are increasing. However, it remains unclear which patient-specific factors have an impact on postoperative activity and whether there is a difference between total and unicompartmental knee arthroplasties (TKA/UKA). MATERIALS AND METHODS: This retrospective study analyzed 1907 knees with TKA (n = 1746) or UKA (n = 161), implanted for primary osteoarthritis. Pain and activity (lower extremity activity scale, LEAS) were assessed 2 years after surgery. High activity was defined as LEAS ≥ 14. Cohorts were compared using Kruskal-Wallis or Pearson-Chi-square test. A generalized least squares model was used to predict LEAS scores between cohorts adjusted for age, sex, BMI, Charlson Comorbidity Index, ASA score, and preoperative LEAS. RESULT: There was no difference in pain 2 years after surgery between UKA and TKA (p = 0.952). Preoperative LEAS was similar for UKA and TKA (p = 0.994), and both groups showed significant (p < 0.001 respectively) and similar improvements after surgery (p = 0.068). LEAS 2 years after surgery was 11.1 (SD 3.2) for TKA and 11.9 (SD 3.5) for the UKA group (p = 0.004). After adjusting for preoperative LEAS, age, sex, BMI, CCI and ASA, the difference was not significant (p = 0.225). Male sex, lower BMI, higher preoperative LEAS, and younger age were associated with higher postoperative LEAS (p < 0.001, respectively). CONCLUSION: Patients can achieve a high level of activity following both TKA and UKA. While the postoperative activity level did not depend on the type of the procedure, younger age, male sex, lower BMI, and a higher preoperative activity level were associated with a higher postoperative activity level.

Midterm results of the Birmingham hip resurfacing: a single-surgeon series.

INTRODUCTION: Birmingham hip resurfacing (BHR) is readily used as alternative to total hip replacement in younger patients. The current study aims to compare outcomes in terms of adverse local tissue reactions (ALTR), elevated metal ion levels and survival rates between low-risk (femoral component size ≥ 48 mm) and high-risk (femoral component size < 48 mm) BHR patients at a minimum 5-year follow-up (FU). MATERIALS AND METHODS: We report the minimum 5-year, single surgeon outcome results of 183 BHRs, performed between 2007 and 2012. 154 patients, 18 women (20 hips) and 136 men (163 hips) were included in the study. Patients were grouped in 149 low-risk cases (femoral component size ≥ 48 mm) and in 34 high-risk cases (18 female/12 male) patients with a femoral head size < 48 mm). RESULTS: At a minimum of 5-years FU time, 91% of the patients were available for FU. The overall survival rate was 91.8%. There were five revisions (survival rate 96.6%) in the low-risk group and ten revisions (survival rate 70.6%) in the high-risk group. In the low-risk group, six patients (6.5%) showed elevated metal ion levels (> 7 µg/l), compared to five patients (20.8%) in the high risk-group (p = 0.03). CONCLUSION: Including the surgeon's initial learning curve, the BHR shows very good mid-term survival rates in the low-risk group but should, as previously demonstrated, not be considered for patients with less than 48 mm femoral head size. LEVEL OF EVIDENCE: Level III: retrospective cohort study.

The impact of the COVID-19 associated shutdown on orthopedic patient care.

BACKGROUND: Due to the surge of COVID-19 cases in the US in early March 2020, health care facilities temporarily suspended elective and non-urgent medical procedures such as joint replacement surgeries. The aim of this study was to analyze the impact of the COVID-19 associated shutdown on orthopedic patient care at a specialized orthopedic hospital located at the epicenter of the COVID-19 pandemic. METHODS: Patient volume of outpatient visits and joint replacement surgeries were analyzed and compared for 2019 and 2020. The volumes were further aligned with the timeline of governmental and institutional COVID-19 associated restrictions. RESULTS: The annual surgery volume was reduced by 20.2% in 2020 and did not make up for the reduction experienced during the shutdown. The total number of patient visits decreased by 25.5% and new patient visits remained 25% lower at the end of 2020. Patient care and surgery volume recovered with declining SARS-CoV-2-cases but did not return to levels prior to the shutdown. During the second quarter of 2020, 28.5% of all patient visits were telehealth appointments. By the end of the year it dropped to 7.6%. There was a shift towards patient appointments at outpatient satellite offices. CONCLUSION: Orthopedic providers faced a substantial disruption in outpatient and surgical volume. Telemedicine appointments were crucial for maintaining follow-up patient care and will be an important sector in future patient care. There has been a major push to utilize satellite offices outside the city center.

Gluteus maximus transfer for wound closure and treatment of abductor deficiency: a single-plastic surgeon series.

INTRODUCTION: Due to the increasing number of total hip arthroplasties (THA), the number and complexity of revision procedures are also on the rise. For complex cases such as periprosthetic joint infections with soft tissue compromise or for abductor muscle deficiencies, one of the treatment options is a gluteus maximus flap (GMF) that covers dead space and can help restore the failed abductor mechanism. The purpose of this study is to investigate the outcomes of a single-plastic surgeon's series of GMF procedures. MATERIALS AND METHODS: This retrospective review reports on 57 patients (mean follow-up 39.2 months) undergoing GMF transfers for abductor insufficiency on native hip (N = 16), for abductor insufficiency in aseptic revision THA (rTHA) (N = 16), for soft tissue defects in aseptic rTHA (N = 8) and for soft tissue defects in septic rTHA (N = 17) by a single plastic surgeon over a 10-year period. Revision-free survival and complication rates were assessed and risk factors were analyzed with Cox-regression analysis. RESULTS: The reoperation-free survival rate of GMF for abductor insufficiency in native hips was 100%. GMF procedures for soft tissue defects in septic rTHA had the lowest cumulative revision-free survival (34.3%) and highest reinfection rates (53.9%). More than three prior surgeries (HR = 2.9, p = 0.020), presence of infection (HR = 3.2, p = 0.010) and resistant organisms (HR = 3.1, p = 0.022) significantly increased the risk of revision. CONCLUSIONS: GMF is a viable option for addressing abductor insufficiency in native hip joints. However, high revision and complication rates are reported for GMF in septic rTHA. This study highlights the need to clarify the circumstances for which the flap reconstruction will be indicated.

Do cobalt and chromium blood metal ion levels normalize after revision of failed metal-on-metal total hip replacements?

INTRODUCTION: Increased cobalt (Co) and chromium (Cr) serum levels are one reason for revision surgery in metal on metal (MoM) total hip arthroplasty (THA) patients. Dual mobility liners are a simple revision option; however, they preserve the metal shell and stem and it is therefore not clear if metal ion levels will fully normalize after revision surgery. MATERIAL AND METHODS: Between April 2013 and December 2017 25 hips (24 patients) underwent revision from a MoM THA to an off-label dual mobility liner. Five patients were lost to follow-up and one patient refused leaving 18 patients (11 men, 7 female, average age 63.9 years) for pre- and postoperative metal ion level blood tests at a minimum follow-up of 2 years. RESULTS: Fourteen patients were revised for osteolysis, two for elevated metal ion levels and two for fluid or cysts around the femoral or acetabular component. The average preoperative Co and Cr levels were 8.3 µg/l and 5.0 µg/l, respectively. At a minimum follow-up of 2 years (30-95 months), metal ions dropped to 0.8 µg/l. Harris Hip Score (HHS), Hip Osteoarthritis Outcome Score (HOOS), Visual Analog Scale (VAS) and the UCLA activity score improved non-significantly from pre- to postoperative. There was one postoperative complication in the study cohort. One patient with persisting pain required revision surgery to a standard acetabular component during the follow-up period. CONCLUSION: The off-label use of a dual-mobility liner in the current study resulted in normalization of the metal ion levels suggesting that preserving the cobalt-chromium acetabular component has little impact on ion levels. In addition, dual mobility liners have a low complication and revision rate.

Preoperative ferritin and hemoglobin levels are lower in patients with a history of COVID-19 but blood loss and transfusion requirements are not increased.

INTRODUCTION: A history of COVID-19 (Coronavirus Disease 2019), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may have an impact on hemoglobin and ferritin levels predisposing patients to increased blood transfusion requirements following total joint arthroplasty (TJA). The current study compares ferritin levels, hemoglobin levels, and transfusion rates between SARS-CoV-2 IgG positive and SARS-CoV-2 IgG negative TJA patients. MATERIALS AND METHODS: Preoperative ferritin levels, pre- and postoperative hemoglobin levels, postoperative change in hemoglobin, and transfusion rates of 385 consecutive SARS-CoV-2 IgG positive patients undergoing TJA were compared to those of 5156 consecutive SARS-CoV-2 IgG negative patients undergoing TJA. RESULTS: Preoperative hemoglobin levels were significantly lower in SARS-CoV-2 IgG positive patients [13.3 g/dL (range 8.9-17.7 g/dL)] compared to 13.5 g/dl (7.3-18.3 g/dL; p value 0.03). Ferritin levels were significantly lower in SARS-CoV-2 IgG positive patients (mean of 106.1 ng/ml (2.1-871.3.3 ng/ml) vs. 123.7 ng/ml (1.4-1985 ng/ml) (p value 0.02)). Hemoglobin on postoperative day (POD) one, after four-six weeks, and transfusion rates did not differ between the two groups. CONCLUSION: Although preoperative hemoglobin and ferritin levels are lower in SARS-CoV2 IgG positive patients, there was no difference in hemoglobin on POD one, recovery of hemoglobin levels at four-six weeks postoperatively, and transfusion rates after surgery. Routine ferritin testing prior to TJA is not recommended in SARS-CoV-2 IgG positive patients.

Is there a difference in mobility and inpatient physical therapy need after primary total hip and knee arthroplasty? A decade-by-decade analysis from 60 to 99 years.

INTRODUCTION: Extended inpatient rehabilitation (PT) after total hip (THA) and knee arthroplasty (TKA) has a significant impact on total care costs. As patients age, extended PT might be required following THA and TKA. This study examined the relationship between patient age, functional mobility, inpatient PT need, and discharge disposition in THA and TKA patients. MATERIALS AND METHODS: This retrospective study included patients aged 60 + undergoing primary THA or TKA between 2018 and 2020 at an orthopedic hospital. Comparing by age-decade, 7374 (3600 THA, 3774 TKA) sexagenarians, 5350 (2367 THA, 2983 TKA) septuagenarians, 1356 (652 THA, 704 TKA) octogenarians, and 78 (52 THA, 26 TKA) nonagenarians were analyzed. We compared the number of PT sessions needed for discharge clearance and the postoperative functional mobility using the Activity Measure for Post-Acute Care (AM-PAC) tool. Statistical analyses included ANOVA with post-hoc Tukey's HSD for continuous data and Chi-squared test for categorical variables. RESULTS: The number of PT sessions required for discharge clearance increased with age after THA (3.3 ± 1.9 sessions vs 3.8 ± 2.1 vs 5.0 ± 2.7 vs 6.2 ± 3.0; p < 0.01) and TKA (4.0 ± 2.1 vs 4.7 ± 3.1 vs 5.2 ± 2.8 vs 5.0 ± 1.6; p < 0.01). The functional mobility improvement as measured by AM-PAC was significantly lower for nonagenarians after THA (4.9 ± 2.8 vs 5.1 ± 2.8 vs 4.6 ± 3.3 vs 3.3 ± 3.9; p < 0.01) and TKA (5.0 ± 2.9 vs 4.7 ± 3.2 vs 3.9 ± 3.4 vs 3.2 ± 2.6; p < 0.01). CONCLUSION: Patients in their eighth and ninth decade had less improvement in functional mobility during in-hospital rehabilitation and utilized more PT services. However, clinical results in the elderly are still satisfying and the data may be helpful for resource utilization planning and risk-adjustment in value-based payment models.

Re-initiation of elective total knee arthroplasty with an adapted pathway during the 2020 COVID-19 pandemic was safe and effective.

INTRODUCTION: In June 2020 when elective total knee arthroplasty (TKA) resumed after the initial COVID-19 surge, we adapted our TKA pathway focusing on a shorter hospitalization, increased home discharge, and use of post-discharge telemedicine and telerehabilitation. The purpose of this study was to evaluate if changes in postoperative care affected early TKA outcomes. MATERIALS AND METHODS: Five hundred and fifty-four patients who underwent elective primary unilateral TKA for primary osteoarthritis between June and August 2020 (study group) were matched 1:1 for age, sex, body mass index, and Charlson comorbidity index with control patients who underwent surgery between August and November 2019. Study patients were discharged 25 h earlier on average compared to controls, more frequently on the same-day or postoperative day-1 (24.9% vs. 16.1%; p = 0.001), and more frequently home (97.3% vs. 83.8%; p < 0.001). Study patients used telemedicine (11.7% vs. 0%; p < 0.001) and telerehabilitation (19.7% vs. 2.5%; p < 0.001) at higher rates than controls. Generalized estimating equations, Mann-Whitney U, and Chi-Square tests were used to compare outcomes between groups including unscheduled office visits, ER visits, readmissions, Center for Medicare and Medicaid Services (CMS) complications, manipulation under anesthesia (MUA), and patient-reported outcomes measures (PROMs). RESULTS: Rates of emergency room visits, readmissions, CMS complications, MUA, and improvements in PROMs were similar between cohorts. Study patients experienced higher rates of unscheduled outpatient visits (9.2% vs. 4.9%; p = 0.004), predominantly due to wound complications. CONCLUSIONS: A protocol implemented during the COVID-19 pandemic that leveraged a shortened hospitalization, higher rates of home discharge, and increased use of telemedicine and telerehabilitation was safe and effective.

History of COVID-19 infection is not associated with increased D-dimer levels and risk of deep-vein thrombosis in total joint arthroplasty.

INTRODUCTION: In the acute phase of COVID-19, elevated D-dimer levels indicate a hypercoagulable state putting the patients at increased risk for venous thromboembolic disease (VTE). It is unclear, if prior COVID-19 disease increases the risk for VTE after total joint arthroplasty (TJA) and if D-dimer levels can be used to identify patients at risk. MATERIALS AND METHODS: D-Dimer levels of 313 consecutive SARS-CoV-2 IgG-positive and 2,053 -negative patients undergoing TJA between 05/20 and 12/20 were evaluated. D-Dimer levels were divided into three groups: < 200 ng/ml, 200-400 ng/ml, and > 400 ng/ml D-dimer units (DDU). 277 SARS-CoV-2 IgG-positive patients underwent a Doppler ultrasound to rule out deep-vein thrombosis (DVT) 4-6 weeks after TJA. RESULTS: D-Dimer levels did not differ significantly between SARS-CoV-2 IgG-positive and -negative patients (p value 0.53). Among SARS-CoV-2 IgG-negative patients, 1687 (82.17%) had D-dimer levels < 200 ng/ml, 256 (12.47%) between 200 and 400 ng/ml, and 110 (5.36%) > 400 ng/ml. Of the SARS-CoV-2 IgG-positive patients, 257 (83.71%) had D-dimer levels < 200 ng/ml, 34 (11.07%) between 200 and 400 ng/ml, and 16 (5.21%) > 400 ng/ml. A postoperative DVT was detected in nine patients (2.9%) in the SARS-CoV-2 IgG-positive group and a PE in one patient (0.3%). 7/229 patients with < 200 ng/ml (3.1%), 1/28 patients (3.6%) with 200-400 ng/ml and 1/9 patients (11.1%) with D-dimer levels > 400 ng/ml had a DVT or PE (p = 0.43). CONCLUSIONS: The findings of this investigation suggest there is no difference in D-dimer levels between SARS-CoV-2 IgG-positive and -negative patients undergoing TJA. Although there is a trend for increased VTE rates with increased D-dimer levels, routine D-dimer testing is not recommended based on the current data. SARS-CoV-2 IgG-positive patients have a low risk of VTE in the current study.

Blood management in direct anterior versus posterior primary total hip arthroplasty using tranexamic acid: a matched cohort study.

INTRODUCTION: Proponents of the direct anterior approach (DAA) for THA claim patients recover faster compared to primary THA through the posterior approach (PA). Blood loss and transfusion have substantially declined with the use of tranexamic acid (TXA). However, it is still controversial if hemoglobin drops and transfusion rates are affected by the surgical approach when TXA is routinely used. MATERIALS AND METHODS: 2418 patients undergoing DAA THA were matched 1:1 with patients undergoing PA THA according to preoperative hemoglobin (± 1 g/dl), age (± 5 years), sex, BMI (± 5 kg/m2) and year of surgery (± 2 years). All patients received perioperative TXA. None of the patients donated autologous blood. Hemoglobin levels, drain placement and output, blood transfusion rates and volume as well as length of stay were recorded. RESULTS: A closed suction drain was used in 121 (5.0%) DAA and in 135 (5.6%) PA THAs (p = 0.369). Mean drain output was higher in the DAA compared to the PA group (134 ml (0-520 ml) versus 92.3 ml (0-600 ml), p = 0.004). There was no difference in hemoglobin drop [2.6 g/dl versus 2.6 g/dl (p = 0.143)] and transfusion rate [n = 31 (1.3%) versus n = 29 (1.2%), p = 0.793)] between DAA and PA THA. Mean transfusion amounts were 421.8 ml (250-1120.8 ml) in the DAA and 353.9 ml (250-560 ml) in the PA group (p = 0.801). The length of stay was shorter in the DAA group with a mean 1.6 days versus 2.1 days in the PA group (p ≤ 0.001). CONCLUSION: In this large matched cohort study, there was no difference in the perioperative hemoglobin drop, the transfusion rate and the transfusion amount between DAA and PA THA.