The change in lumbar lordosis from the standing to the lateral position: implications for lateral interbody fusion.

PURPOSE: The purpose of this cross-sectional, observational study was to establish the relationship between standing lumbar lordosis (LL) and lateral decubitus LL. METHODS: Forty-nine subjects, 24 male and 25 female, were prospectively enrolled. Patients with pre-existing spinopelvic pathology were excluded. Standing, relaxed-seated, and lateral decubitus lateral radiographs were obtained. Radiographic variables measured included LL and lordosis change at each lumbar level (e.g. L1-L2). The change in LL when going from a standing to a lateral decubitus position (ΔLL), the correlation between standing and sitting LL compared to lateral decubitus LL, and the correlation between ΔLL and standing pelvic incidence (PI), pelvic tilt (PT), PI-LL mismatch, pelvic femoral angle (PFA), and sacral slope (SS) were calculated. RESULTS: Subjects had an average age of 25.7 ± 2.3 years and body mass index of 24.1 ± 3.0 kg/m2. On average, 11.9°±8.2° (range - 7° to 29°) of LL was lost when transitioning from a standing to the lateral decubitus position. Lateral decubitus LL had a higher correlation with standing LL (R = 0.725, p < 0.001) than with relaxed-seated LL (R = 0.434, p < 0.001). Standing PT and PI-LL mismatch had moderately negative correlations with ΔLL (R=-0.58 and R=-0.59, respectively, both p < 0.05). Standing PI and standing PFA had a low negative correlation with ΔLL (R=-0.31 and R=-0.44, respectively, both p < 0.05) Standing SS and LL had no correlation with ΔLL. CONCLUSIONS: Standing LL was strongly correlated to lateral decubitus LL, although subjects lost an average of 11.9° from the standing to the lateral decubitus position. This has important implications for fusion in the lateral position.

Super-Obesity is Associated With an Increased Risk of Complications Following Primary Total Knee Arthroplasty.

BACKGROUND: Obesity, defined as a body mass index (BMI) ≥ 30, is an ever-growing epidemic, with > 35% of adults in the United States currently classified as obese. Super-obese individuals, defined as those who have a BMI ≥ 50, are the fastest-growing portion of this group. This study sought to quantify the infection risk as well as the incidence of surgical, medical, and thromboembolic complications among super-obese patients undergoing total knee arthroplasty (TKA). METHODS: An all-payer claims database was used to identify patients who underwent elective, primary TKA between 2016 and 2021. Patients who had a BMI ≥ 50 were compared to those who had a normal BMI of 18 to 25. Demographics and the incidence of 90-days postoperative complications were compared between the 2 groups. Univariate analysis and multivariable regression were used to assess differences between groups. RESULTS: In total, 3,376 super-obese TKA patients were identified and compared to 17,659 patients who had a normal BMI. Multivariable analysis indicated that the super-obese cohort was at an increased postoperative risk of periprosthetic joint infection (adjusted odds ratio [aOR] 3.7, 95% confidence interval [CI]: 2.1 to 6.4, P < .001), pulmonary embolism (aOR 2.2, 95%-CI: 1.0 to 5.0, P = .047), acute respiratory failure (aOR 4.1, 95%-CI: 2.7 to 6.1, P < .001), myocardial infarction (aOR 2.5, 95%-CI: 1.1 to 5.8, P = .026), wound dehiscence (aOR 2.3, 95%-CI: 1.4 to 3.8, P = .001), and acute renal failure (aOR 3.2, 95%-CI: 2.4 to 4.2, P < .001) relative to patients who have normal BMI. CONCLUSIONS: Super-obese TKA patients are at an elevated risk of postoperative infectious, surgical, medical, and thromboembolic complications. As such, risk stratification, as well as appropriate medical management and optimization, is of utmost importance for this high-risk group.

The Utility of Routine Postoperative Radiographs in the Asymptomatic Total Hip Arthroplasty Patient.

BACKGROUND: Total hip arthroplasty (THA) patients often receive routine radiographs in the year following their index surgery. This study sought to investigate the clinical and economic value of obtaining routine postoperative hip radiographs for asymptomatic patients following primary elective THA. METHODS: A retrospective cohort study of consecutive patients who underwent primary elective THA from 2016 to 2019 was conducted. Patients undergoing nonelective or revision THA, radiographic follow-up <10 months, and patients aged <18 years were excluded. All radiographs were reviewed for abnormalities in the first postoperative year by an arthroplasty fellowship-trained orthopaedic surgeon, blinded to the symptoms of the patient. RESULTS: Of the 327 patients (351 hips) included, 57.2% were women and 68.2% were White, with an average age of 65 years (range, 22-97 years) and average body mass index of 29.1 kg/m2 (range, 16.2-49.8 kg/m2). Only four (0.4%) radiographic series revealed abnormalities with the potential to alter postoperative management. One patient experienced a change in management directly related to their abnormal finding (closed reduction for dislocation at 10.2 months postoperatively). The remaining three abnormal radiographic findings included femoral stem subsidence, progressive radiolucencies around an acetabular component, and cement mantle fracture. The average cost for each radiographic series was $155.27, resulting in total direct charges of $167,691.60. CONCLUSION: Routine postoperative radiographs may be of limited utility in the asymptomatic patient in the first year following elective primary THA. Consideration should be given to limit postoperative radiographs following standard elective THA, while reserving postoperative radiographic evaluation for patients who are symptomatic. LEVEL OF EVIDENCE: Level III.

Ceramic Femoral Heads Exhibit Lower Wear Rates Compared to Cobalt Chrome: A Meta-Analysis.

BACKGROUND: Wear between the femoral head and acetabular liners continues to limit the longevity of total hip arthroplasty implants despite advances in implant materials. The purpose of this meta-analysis was to compare linear wear rates of cobalt-chromium (CoCr) and fourth-generation ceramic femoral heads on highly cross-linked polyethylene (XLPE) liners. METHODS: A systematic review following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was conducted to identify all studies between 2003 and 2020 that examined in vivo wear rates of either fourth-generation ceramics or CoCr femoral heads on XLPE liners. Studies were analyzed in a weighted means analysis of wear rates and a random effects meta-analysis. RESULTS: A total of 36 studies met inclusion criteria (1,657 CoCr and 659 ceramic patients). The pooled, weighted mean wear rate was 0.063 mm/year (standard deviation [SD]: 0.061, confidence interval [CI]: 0.049-0.077) for CoCr and 0.047 mm/year (SD: 0.057, CI: 0.033-0.062; P < .01) for ceramic (P < .01). A meta-analysis of 4 studies directly comparing ceramic and CoCr found that CoCr heads demonstrated 0.029 mm/year more wear than ceramic heads (95% CI: 0.026-0.059, P = .306). Mean wear for 32-mm heads was significantly higher for ceramic (P < .01), while mean wear for 36-mm heads was significantly higher for CoCr (P < .01). CONCLUSION: Fourth-generation ceramic femoral heads were found to have significantly lower wear rates than CoCr heads. Unlike previous studies, this meta-analysis included only in vivo studies and those with the same generation of highly XLPE liners.

Positive COVID-19 Diagnosis Following Primary Elective Total Joint Arthroplasty: Increased Complication and Mortality Rates.

BACKGROUND: This study analyzed complication rates following primary elective total joint arthroplasty (TJA) in patients who subsequently contracted COVID-19. METHODS: A large national database was queried for adult patients who underwent primary elective TJA in 2020. Patients who contracted COVID-19 after total knee arthroplasty (TKA) or total hip arthroplasty (THA) underwent 1:6 matching (age [±6 years], sex, month of surgery, COVID-19-related comorbidities) to patients who did not. Differences between groups were assessed using univariate and multivariate analyses. Overall, 712 COVID-19 patients were matched to 4,272 controls (average time to diagnosis: 128-117 days [range, 0-351]). RESULTS: Of patients diagnosed <90 days postoperatively, 32.5%-33.6% required COVID-19-driven readmission. Discharge to a skilled nursing facility (adjusted odds ratio [aOR] 1.72, P = .003) or acute rehabilitation unit (aOR 4.93, P < .001) and Black race (aOR 2.28, P < .001) were associated with readmission after TKA. Similar results were associated with THA. COVID-19 patients were at increased risk of pulmonary embolism (aOR 4.09, P = .001) after TKA and also periprosthetic joint infection (aOR 4.65, P < .001) and sepsis (aOR 11.11, P < .001) after THA. The mortality rate was 3.51% in COVID-19 patients and 7.94% in readmitted COVID-19 patients compared to 0.09% in controls, representing a 38.7 OR and 91.8 OR of death, respectively. Similar results were observed for TKA and THA separately. CONCLUSION: Patients who contracted COVID-19 following TJA were at greater risk of numerous complications, including death. These patients represent a high-risk cohort who may require more aggressive medical interventions. Given the potential limitations presently, prospectively collected data may be warranted to validate these findings.

Refining the Role of Routine Synovial Alpha-Defensin in Periprosthetic Joint Infection Following Total Knee Arthroplasty: An Analysis of Limitations.

BACKGROUND: The utility of the synovial alpha-defensin test in diagnosing periprosthetic joint infections (PJIs) remains controversial. This study aimed to examine the diagnostic utility of this test. METHODS: A retrospective review was conducted to identify adults evaluated for PJI following total knee arthroplasty at a single institution. Patient demographics, laboratory results, and operative details were recorded. Using the 2018 Musculoskeletal Infection Society (MSIS) criteria, cases were categorized as definitive, inconclusive, or negative for PJI. The sensitivity, specificity, positive predictive value, and negative predictive value of each MSIS criterion was determined. The number of patients whose PJI diagnosis was contingent on alpha-defensin positivity was calculated. RESULTS: Overall, 172 total knee arthroplasty patients were included, who had an average age of 70.4 years (range, 39 to 95). Of the 21 patients who met major criteria, 20 (95.2%) were alpha-defensin positive. Of the remaining 151 patients, 85 did not meet minor criteria, all of whom were alpha-defensin negative. Among the 30 patients who met minor criteria, 28 (93.3%) were alpha-defensin positive and 2 (6.7%) were negative. The remaining 36 patients were deemed inconclusive preoperatively. In total, alpha-defensin testing changed the diagnosis in only 9 of 172 patients (5.2%). The sensitivity, specificity, positive predictive value, and negative predictive value of alpha-defensin in this cohort were 94.1, 100, 100, and 97.6, respectively. CONCLUSION: Alpha-defensin may assist in the diagnosis of PJI when a preoperative workup is inconclusive. However, this test is often unnecessary when the diagnosis of PJI can be made using the 2018 MSIS criteria.

The Persistent Effects of the COVID-19 Pandemic on Total Joint Arthroplasty Changes in Practice Patterns in the United States From 2020 to 2021.

BACKGROUND: The SARS-CoV-2 (COVID-19) pandemic has dramatically disrupted orthopaedic surgery practice patterns. This study aimed to examine differences between patients who underwent total joint arthroplasty (TJA) before the pandemic compared to 2020 and 2021. METHODS: A retrospective cohort study was performed on all patients who underwent elective inpatient TJA from January 2017 to December 2021 using a national large database. Descriptive statistics were utilized to trend length of stay (LOS) and patient age. Patient demographics, discharge destinations, and rates of medical comorbidities were assessed for patients undergoing TJA in 2020 and 2021 compared to patients from prepandemic years (2017 to 2019). Overall, 1,173,366 TJAs were identified (2017 to 2019: 810,268 TJAs, average 270,089 cases/year; 2020: 175,185 TJAs; 2021: 187,627 TJAs). There was a 35.3% and 30.5% decrease in 2020 and 2021, respectively, when compared to the prepandemic annual average. RESULTS: Average LOS decreased from 1.6 days in January 2020 to 0.9 days by December 2021. Same-day discharges increased from 6.2% of cases in 2019 to 30.5% in 2021. Discharge to skilled nursing facilities (SNF) reduced from 11.3% in 2017 to 2019 to 4.3% and 4.5% in 2020 and 2021, respectively. Patients ≥70 years old undergoing elective TJA decreased from 39.6% in 2017 to 2019 to 29.2% in April 2020. CONCLUSION: In response to the COVID-19 pandemic, same-day discharges following primary elective TJA increased markedly, the average LOS decreased, discharges to SNFs decreased, and a preferential shift toward younger patients was observed. LEVEL OF EVIDENCE: Therapeutic Level III.

The Effect of Hip Offset and Spinopelvic Abnormalities on the Risk of Dislocation Following Total Hip Arthroplasty.

BACKGROUND: Previous studies have demonstrated that patients with abnormal spinopelvic motion are at increased risk of dislocation. However, little is known about the effect of hip offset on dislocation risk following total hip arthroplasty (THA) in patients with abnormal spinopelvic motion. The purpose of this study is to investigate the prevalence of under-restored hip offset and spinopelvic abnormalities in a series of THA patients treated for recurrent instability. METHODS: This is a retrospective review of consecutive patients treated for hip instability following primary THA (THA+I) from 2012 to 2020. Patient demographics, surgical variables, and radiographic parameters were recorded. THA+I patients were compared to an age-matched and gender-matched control THA population without hip instability (THA). Univariate analyses were performed to compare differences between groups. RESULTS: Thirty-three THA+I patients (44 hips) were compared to 44 THA patients (44 hips). THA+I patients had a higher prevalence of spinopelvic pathology (odds ratio [OR] 7.80, 95% confidence interval [CI] 2.59-23.50, P < .001). The majority of acetabular components were placed within the Lewinnek safe zone (86.4% THA+I vs 72.7% THA; P = .119). THA+I patients were at greater risk of markedly under-restored hip offset (Δoffset ≤ 3 mm; OR 6.34, 95% CI 2.20-18.30, P = .001) and small (<32 mm) femoral head diameter (OR 4.38, 95% CI 1.53-12.53, P = .006) compared to THA patients. CONCLUSION: Lumbar degenerative disease and under-restoration of hip offset were present in a high proportion of patients with hip instability. Although multiple factors may contribute to THA instability, these data suggest that restoration of offset is essential, particularly in patients with spinopelvic pathology, and may be more important than historically described acetabular targets. LEVEL OF EVIDENCE: Level III.

Modern Proximal Femoral Replacement in Revision Total Hip Arthroplasty for Nononcologic Indications.

BACKGROUND: Advances in surgical technique and prosthesis design have expanded the non-neoplastic indications for proximal femoral replacement (PFR) to include fracture nonunion, periprosthetic fracture, and severe bone loss in the setting of revision total hip arthroplasty (THA). The purpose of this study is to assess outcomes of PFRs used for nononcologic indications. METHODS: A single-institution, retrospective, cohort survey study was conducted between August 2015-February 2020 of consecutive patients undergoing PFR for nononcologic indications in revision THA. Patient demographics, surgical variables, complications, and revision procedures were collected. Patient satisfaction and Oxford Hip scores were assessed via a telephone questionnaire. Implant survivorship was estimated using the Kaplan-Meier method. RESULTS: In total, 24 patients (27 PFRs) were available for analysis with an average age of 69.3 ± 12.9 years (range: 37-90). The average number of operations prior to PFR implantation was 3.1 ± 2.1 (range: 0-7). At a mean follow-up of 2.4 years (range: 0.5-5.1), the mean Oxford Hip Score was 31.7 ± 10.2, and mean patient satisfaction was 4.9/5. Six patients (20.7%) experienced a postoperative complication, with dislocation occurring in three patients (10.3%). None of the patients with dual mobility articulations (n = 4) had dislocation. Three-year survivorship was 85.2% (95% CI 71.8%-98.6%) with all-cause reoperations as the endpoint and 100% (95% CI 100.0%-100.0%) with revision for aseptic loosening as the endpoint. CONCLUSION: The current study demonstrates excellent short-term survivorship, satisfactory patient-reported outcomes, and high patient satisfaction following PFR for nononcologic indications during revision THA utilizing modern techniques. The most common mode of failure was dislocation requiring reoperation with revision to constrained acetabular components.

Midterm Survivorship of Robotic-Assisted Lateral Unicompartmental Knee Arthroplasty.

BACKGROUND: Lateral unicompartmental knee arthroplasty (UKA) is a popular alternative to total knee arthroplasty (TKA) for patients with isolated lateral compartment osteoarthritis. Few studies have investigated outcomes following robotic-assisted lateral UKA. The purpose of this study is to evaluate mid-term survivorship and patient-reported outcomes of robotic-assisted lateral UKA. METHODS: A retrospective case series was conducted on all robotic-assisted lateral UKAs performed by a single surgeon between 2013 and 2019. Patient demographics, surgical variables, and Kozinn and Scott criteria were collected. Implant survivorship was estimated using the Kaplan-Meier method with all-cause reoperation and conversion to TKA as endpoints. Participating patients were assessed for patient satisfaction and the Forgotten Joint Score-12. Correlations between patient demographics and patient outcome scores were investigated. RESULTS: In total, 120 lateral UKAs were identified, 84 of which met inclusion criteria, with a mean follow-up of 4.0 years (range 2.0-7.0). Five-year survivorship was 92.9% (95% confidence interval [CI] 84.5-96.7) with all-cause reoperation as the endpoint, and 100% (95% CI 95.0-100) with conversion to TKA as the endpoint. One patient was converted to TKA after the 5-year mark, resulting in a 6-year survival for conversion to TKA of 88.9% (95% CI 44.9-98.5). Average Forgotten Joint Score-12 score was 82.7/100, and patient satisfaction 4.7/5. Mean coronal plane correction was 2.5° ± 1.9° toward the mechanical axis. Neither final postoperative alignment nor failure to meet classic Kozinn and Scott criteria for UKA resulted in differences in patient-reported outcomes. CONCLUSION: The current study demonstrates high mid-term survivorship and excellent patient-reported outcomes with robotic-assisted lateral UKA. Robotic-assisted lateral UKA is a viable treatment option for isolated lateral compartment arthritis even in patients who do not meet classic indications.

Delayed debridement of open tibia fractures beyond 24 and 48 h does not appear to increase infection and reoperation risk.

PURPOSE: Surgical debridement is critical to the treatment of open tibia fractures, although the effects of delayed debridement have not been well-established. Other factors such as Gustilo-Anderson type, prompt initiation of antibiotics, and time to definitive closure may be more predictive of infection than time to surgery. We sought to determine the effect of a prolonged delay to surgical debridement with respect to infection and reoperation rates for open tibia fractures. METHODS: All open diaphyseal tibia fractures with > 12-week follow-up were evaluated. Patient demographics, Gustilo-Anderson type, and rates of deep infection and all-cause reoperation were recorded. Patients were divided into 3 groups based on time to surgery: early (< 24 h), delayed (24-48 h), and late (> 48 h). Univariate and multivariate analyses were performed to evaluate the relationship between time to surgery, fracture type, infection, and reoperation. RESULTS: In total, 96 open tibia fractures with average follow-up of 59.3 weeks and infection rate of 13.5% were included. Infection rates for the early, delayed, and late groups were 13.3%, 17.2%, and 9.1%, respectively (p = 0.70). Reoperation rates for the early, delayed, and late groups were 29.8%, 31.0%, and 22.7%, respectively (p = 0.80). The groups did not vary in proportion of Gustilo-Anderson fracture types; infection rates between Gustilo-Anderson types were similar (p = 0.57). Type IIIA-C fractures required more reoperations than other fracture types (p = 0.01). CONCLUSION: Delayed surgical debridement of open tibia fractures did not result in greater rates of infection or reoperation. Gustilo-Anderson classification was more predictive of reoperation, with Type IIIA-C injuries having a significantly higher reoperation rate.

Limb Length Discrepancy in Total Hip Arthroplasty: Is the Lesser Trochanter a Reliable Measure of Leg Length?

BACKGROUND: Limb length discrepancy (LLD) after total hip arthroplasty may affect clinical outcomes and patient satisfaction. Preoperative LLD estimates on anteroposterior pelvic radiographs fail to account for anatomical limb variation distal to the femoral reference points. The objective of this study is to determine how variations in lower limb skeletal lengths contribute to true LLD. METHODS: Full-length standing anteroposterior radiographs were used to measure bilateral leg length, femoral length, and tibial length. Leg length was evaluated using 2 different proximal reference points: the center of the femoral head (COH) and the lesser trochanter (LT). Mean side-to-side discrepancy (MD) and percentage asymmetry (%AS) for each measurement were evaluated in the overall cohort and when stratified by patient demographic variables. RESULTS: One hundred patients were included with an average age of 62.9 ± 11.2 years. Average femoral length was 434.0 ± 39.8 mm (MD 4.3 ± 3.5 mm) and tibial length was 379.9 ± 34.6 mm (MD 5.9 ± 12.7 mm). Average COH-talus was 817.5 ± 73.2 mm (MD 6.4 ± 5.1 mm). Average LT-talus was 760.5 ± 77.6 mm (MD 5.8 ± 5.1 mm). Absolute asymmetry >10 mm was detected in 16% of patients for COH-talus and 15% for LT-talus, while %AS >1.5% was detected in 13% of patients for COH-talus and 18% for LT-talus. Female gender was associated with increased femoral length %AS (P = .037). CONCLUSION: Approximately 1 in 6 patients have an LLD of >10 mm when measured from either the LT or COH. Surgeons using either of these common femoral reference points to estimate LLD on pelvic radiographs should consider these findings when planning for hip reconstruction. LEVEL OF EVIDENCE: Level III.

Cemented Vs Cementless Femoral Fixation for Total Hip Arthroplasty After Displaced Femoral Neck Fracture: A Nationwide Analysis of Short-Term Complications and Readmission Rates.

BACKGROUND: Active patients with displaced femoral neck fractures are often treated with total hip arthroplasty (THA). However, optimal femoral fixation in these patients is controversial. The purpose of this study was to compare early complication and readmission rates in patients with hip fracture treated with THA receiving cemented vs cementless femoral fixation. METHODS: The National Readmissions Database was queried to identify patients undergoing primary THA for femoral neck fracture from 2016 to 2017. Postoperative complications and unplanned readmissions at 30, 90, and 180 days were compared between patients treated with cemented and cementless THA. Univariate and multivariate analyses were performed to compare differences between groups and account for confounding variables. RESULTS: Of 17,491 patients identified, 4427 (25.3%) received cemented femoral fixation and 13,064 (74.7%) cementless. The cemented group was significantly older (77.2 vs 71.1, P < .001), had more comorbidities (Charlson comorbidity index: 4.44 vs 3.92, P < .001), and had a greater proportion of women (70.5% vs 65.2%, P < .001) compared with the cementless group. On multivariate analysis, cemented fixation was associated with reduced rates of periprosthetic fracture (odds ratio: 0.052, 95% confidence interval: 0.003-0.247, P = .004) at 30 days but similar readmission rates at 30, 90, and 180 days (odds ratio range: 1.012-1.114, P > .05) postoperatively compared with cementless fixation. Cemented fixation was associated with greater odds of medical complications at 180 days postoperatively (odds ratio:: 1.393, 95% confidence interval: 1.042-1.862, P = .025). CONCLUSION: Cemented femoral fixation was associated with a lower short-term incidence of periprosthetic fractures, higher incidence of medical complications, and equivalent unplanned readmission rates within 180 days postoperatively compared with cementless fixation in patients undergoing THA for femoral neck fracture. LEVEL OF EVIDENCE: Level III.

Fracture of the Proximal Body of a Modern Cementless Modular Fluted Tapered Stem.

Previous reports have described failures of modular fluted tapered femoral stems secondary to fatigue failure at the modular junction. However, the present study is the first reported case of modular fluted tapered femoral component failure involving atraumatic fracture of the proximal body following revision total hip arthroplasty. The failure occurred in a 52-year-old female with a history of postmenopausal osteoporosis on bisphosphonates who sustained an atraumatic fracture of the proximal body of a modular revision femoral stem. In the present case, revision THA utilizing a wider proximal body segment with proximal augmentation using strut allografts for biological and mechanical support provided the patient with a stable construct at 30-month follow-up.

Trabecular Metal Augments During Complex Primary Total Hip Arthroplasty.

Background: Trabecular metal augments (TMAs) have been extensively used in revision total hip arthroplasty (THA) to address acetabular bone defects. However, limited data exists regarding TMA utilization during primary THA. This study aims to assess the clinical and radiographic outcomes of TMAs used during primary THA. Methods: A single-institution retrospective case series of primary THA patients treated with TMA between 2010 and 2019 was performed. Patient demographics, complications, and revisions were recorded. Cup position, center of rotation, leg length, and radiolucent lines were assessed radiographically. The Kaplan-Meier method was used to compute implant survivorship. Results: Twenty-six patients (30 hips) were included with average age of 52.6 ± 15.3 years (range: 22-78) and mean follow-up of 4.1 ± 2.1 years (range: 2.0-8.9). Most TMAs were indicated for developmental dysplasia of the hip (n = 18; 60.0%). On average, hip center of rotation was lowered 1.5 ± 1.3 cm and lateralized 1.2 ± 1.5 cm, while leg length and global offset were increased by 2.4 ± 1.2 cm and 0.4 ± 1.0 cm, respectively. At final follow-up, 3 hips (10.0%) required revision: one (3.3%) for aseptic loosening and 2 (6.7%) for instability. No patients had progressive radiolucent lines at final follow-up. Five-year survival with aseptic loosening and all-cause revision as endpoints was 100% (95% confidence interval: 90.0%-100.0%) and 92.1% (95% confidence interval: 81.3%-100.0%), respectively. One patient required revision for aseptic loosening after the 5-year mark. Conclusions: Trabecular metal augmentation during primary THA demonstrates satisfactory early to mid-term outcomes. TMA is a viable option for complex primary THA when bone loss is encountered or secondary support is required. Level of Evidence: Level IV.

Metal artifact reduction sequence-MRI abnormalities in asymptomatic patients with dual-mobility hip prostheses.

Aims: Modular dual-mobility (DM) articulations are increasingly used during total hip arthroplasty (THA). However, concerns remain regarding the metal liner modularity. This study aims to correlate metal artifact reduction sequence (MARS)-MRI abnormalities with serum metal ion levels in patients with DM articulations. Methods: A total of 45 patients (50 hips) with a modular DM articulation were included with mean follow-up of 3.7 years (SD 1.2). Enrolled patients with an asymptomatic, primary THA and DM articulation with over two years' follow-up underwent MARS-MRI. Each patient had serum cobalt, chromium, and titanium levels drawn. Patient satisfaction, Oxford Hip Score, and Forgotten Joint Score-12 (FJS-12) were collected. Each MARS-MRI was independently reviewed by fellowship-trained musculoskeletal radiologists blinded to serum ion levels. Results: Overall, two patients (4.4%) had abnormal periprosthetic fluid collections on MARS-MRI with cobalt levels > 3.0 µg/l. Four patients (8.9%) had MARS-MRI findings consistent with greater trochanteric bursitis, all with cobalt levels < 1.0 µg/l. A seventh patient had a periprosthetic fluid collection with normal ion levels. Of the 38 patients without MARS-MRI abnormalities, 37 (97.4%) had cobalt levels < 1.0 µg/l, while one (2.6%) had a cobalt level of 1.4 µg/l. One patient (2.2%) had a chromium level > 3.0 µg/l and a periprosthetic fluid collection. Of the 41 patients with titanium levels, five (12.2%) had titanium levels > 5.0 µg/l without associated MARS-MRI abnormalities. Conclusion: Periprosthetic fluid collections associated with elevated serum cobalt levels in patients with asymptomatic DM articulations occur infrequently (4.4%), but further assessment is necessary due to implant heterogeneity.

Anteroposterior pelvic radiograph findings correlate with sagittal spinopelvic motion.

It has been well documented in the arthroplasty literature that lumbar degenerative disc disease (DDD) contributes to abnormal spinopelvic motion. However, the relationship between the severity or pattern of hip osteoarthritis (OA) as measured on an anteroposterior (AP) pelvic view and spinopelvic biomechanics has not been well investigated. Therefore, the aim of the study is to examine the association between the severity and pattern of hip OA and spinopelvic motion. A retrospective chart review was conducted to identify patients undergoing primary total hip arthroplasty (THA). Plain AP pelvic radiographs were reviewed to document the morphological characteristic of osteoarthritic hips. Lateral spine-pelvis-hip sitting and standing plain radiographs were used to measure sacral slope (SS) and pelvic femoral angle (PFA) in each position. Lumbar disc spaces were measured to determine the presence of DDD. The difference between sitting and standing SS and PFA were calculated to quantify spinopelvic motion (ΔSS) and hip motion (ΔPFA), respectively. Univariate analysis and Pearson correlation were used to identify morphological hip characteristics associated with changes in spinopelvic motion. In total, 139 patients were included. Increased spinopelvic motion was observed in patients with loss of femoral head contour, cam deformity, and acetabular bone loss (all p < 0.05). Loss of hip motion was observed in patients with loss of femoral head contour, cam deformity, and acetabular bone loss (all p < 0.001). A decreased joint space was associated with a decreased ΔPFA (p = 0.040). The presence of disc space narrowing, disc space narrowing > two levels, and disc narrowing involving the L5-S1 segment were associated with decreased spinopelvic motion (all p < 0.05). Preoperative hip OA as assessed on an AP pelvic radiograph predicts spinopelvic motion. These data suggest that specific hip osteoarthritic morphological characteristics listed above alter spinopelvic motion to a greater extent than others.

Cemented versus Cementless Femoral Fixation for Elective Primary Total Hip Arthroplasty: A Nationwide Analysis of Short-Term Complication and Readmission Rates.

Cementless fixation during total hip arthroplasty (THA) is the predominant mode of fixation utilized for both acetabular and femoral components during elective primary THAs performed in the United States. This study aims to compare early complication and readmission rates between primary THA patients receiving cemented versus cementless femoral fixation. The 2016-2017 National Readmissions Database was queried to identify patients undergoing elective primary THA. Postoperative complication and readmission rates at 30, 90, and 180 days were compared between cemented and cementless cohorts. Univariate analysis was conducted to compare differences between cohorts. Multivariate analysis was performed to account for confounding variables. Of 447,902 patients, 35,226 (7.9%) received cemented femoral fixation, while 412,676 (92.1%) did not. The cemented group was older (70.0 vs. 64.8, p < 0.001), more female (65.0% vs. 54.3%, p < 0.001), and more comorbid (CCI 3.65 vs. 3.22, p < 0.001) compared to the cementless group. On univariate analysis, the cemented cohort had decreased odds of periprosthetic fracture at 30 days postoperatively (OR: 0.556, 95%-CI 0.424-0.729, p < 0.0001), but higher odds of hip dislocation, periprosthetic joint infection, aseptic loosening, wound dehiscence, readmission, medical complications, and death at all timepoints. On multivariate analysis, the cemented fixation cohort demonstrated reduced odds of periprosthetic fracture at all postoperative timepoints: 30 (OR: 0.350, 95%-CI 0.233-0.506, p < 0.0001), 90 (OR: 0.544, 95%-CI 0.400-0.725, p < 0.0001), and 180 days (OR: 0.573, 95%-CI 0.396-0.803, p = 0.002). Cemented femoral fixation was associated with significantly fewer short-term periprosthetic fractures, but more unplanned readmissions, deaths, and postoperative complications compared to cementless femoral fixation in patients undergoing elective THA.

Preoperative radiographic findings associated with postoperative spinopelvic risk factors for instability following total hip arthroplasty.

Postoperative spinopelvic changes are associated with increased dislocation risk following total hip arthroplasty (THA). The aim of this study was to identify preoperative patient and radiographic factors associated with high-risk postoperative spinopelvic parameters. A retrospective review of consecutive THA patients who received preoperative and postoperative sitting and standing lateral lumbar spine-hip radiographs with minimum radiographic and clinical follow-up of 10 months was performed. Patient demographics were recorded and preoperative standing and sitting sacral slope (SS), anteinclination, pelvic femoral angle (PFA), and combined sagittal index (CSI) were measured. High-risk patients were defined by decreased spinopelvic motion (∆SS from sitting to standing of >10°), increased hip motion (∆PFA from sitting to standing of >10°), or decreased CSI of >10° at final follow-up compared with preoperative measurements. Univariate and multivariate regression analyses were used to identify preoperative demographic and radiographic factors associated with these high-risk categories. One hundred and fifty-three patients were included with an average age of 62 years, average body mass index of 27.8 kg/m2 , and average follow-up of 16.2 months. At 1-year follow-up, 43 (28.1%) patients demonstrated a decreased ∆SS > 10° and 67 (43.7%) patients demonstrated an increased ∆PFA > 10° compared with preoperative values. Sitting CSI decreased by >10° in 17 (11.1%) patients. Preoperative increased sitting PFA (adjusted odds ratio [aOR] 1.057, p < 0.001) and decreased preoperative hip motion (∆PFA) were associated with decreased sitting CSI of >10° at 10-month follow-up. Increased spinopelvic motion (∆SS) and decreased hip motion (∆PFA) preoperatively are associated with postoperative radiographic changes that be associated with increased dislocation risk.