Projections and Epidemiology of Revision Hip and Knee Arthroplasty in the United States to 2030

Preoperative SSRI use increases perioperative transfusion need in patients undergoing surgical procedures on the hip joint

PURPOSE

Selective serotonin reuptake inhibitors (SSRIs) are commonly prescribed for psychiatric conditions. Previous studies have shown that SSRIs can increase bleeding risk by affecting platelet aggregation. However, their impact on perioperative outcomes in hip surgery remains uncertain. This case-control study examines the link between preoperative SSRI use and perioperative transfusion requirements in hip surgery patients.

METHODS

Data from the M161Ortho dataset of Pearl Diver patient records database were utilized. Patients who underwent hip joint surgery between 2010 and 2022 and had documented preoperative SSRI use within one month prior to surgery were included. Patients with coagulopathy disorders or coagulopathy medication use were excluded. Perioperative transfusion need was defined as receiving red blood cell or whole blood transfusions on the same date or within 10 days following the surgery.

RESULTS

A total of 75,374 patients with preoperative SSRI use were matched with an equal number of non-SSRI users. Preoperative SSRI use was associated with an increased risk of requiring perioperative transfusion (5.7% vs. 5.1%, P < 0.001). Subgroup analysis demonstrated increased transfusion risk in patients undergoing pinning (2.6% vs. 1.8%, P = 0.02), open reduction with internal fixation (ORIF) (8.9% vs. 8.2%, P = 0.007), and total hip arthroplasty (THA) (3.8% vs. 3.4%, P < 0.001), but no significant difference was observed in patients undergoing hemiarthroplasty.

CONCLUSION

Clinicians should be aware of the potential risk of increased perioperative transfusion requirements in hip surgery patients using SSRIs, especially during pinning, ORIF, and THA procedures. It is essential to consider this when managing patients on SSRIs before hip surgery.

Periprosthetic Joint Infection: What's New?

Total joint arthroplasty (TJA) ranks among the most commonly performed orthopedic surgeries, with its annual incidence on the rise globally. Periprosthetic joint infection (PJI) remains a leading cause of arthroplasty failure. This review aims to summarize recent literature updates on the epidemiology, diagnosis, and management of PJI.

Osteoinductivity enhancement by tailoring the surface chemical bond status: A strategy to mobilize host bone growth factors for in situ bone regeneration

The incorporation of growth factors and biomaterials is a promising strategy for improving osseointegration. However, current strategies to develop biomaterials with exogenous growth factors present disadvantages like inefficiency, difficult deployment, and potential off-target activation, making their translation into clinical practice challenging. This study reveals a bioactive N-doped tantalum carbide (TaC) solid solution film that can be used to construct a TaCN film via bionic interface engineering to recruit host bone growth factors to the wounded site and improve bone regeneration. X-ray photoelectron spectroscopy (XPS) and protein absorption analysis reveal that the performance of TaCN is related to the surface chemical bonds of films. The introduction of N to TaC causes a cascade effect wherein negative charges enrich on the TaCN surface, and the recruitment of positively charged bone growth factors around the TaCN film is facilitated. Under these circumstances, the endogenous bone growth factors enhance bone healing. The TaCN film shows an outstanding performance for in vivo osteogenic differentiation along with a superior in vitro cytocompatibility. Incorporation of N atoms into TaC provides a new clinically translatable strategy to mobilize host bone growth factors for in situ bone regeneration without the need for incorporation of exogenous growth factors.

Use of Peripheral Nerve Blocks for Total hip Arthroplasty

PURPOSE OF REVIEW

The purpose of this review is to summarize the recent literature regarding regional anesthesia (RA) techniques and outcomes for total hip arthroplasty (THA) in the face of changing surgical techniques and perioperative considerations.

RECENT FINDINGS

Based on large meta-analyses, peripheral nerve blocks are indicated for THA. Each block has its own risks and benefits and data for outcomes for particular techniques are limited. New surgical techniques, improved use of multimodal analgesia, and improved ultrasound guided regional anesthetics lead to better pain control for patients undergoing THA with less associated risks. Block selection continues to be influenced by provider comfort, surgical approach, patient anatomy, and postoperative goals. Head-to-head studies of particular nerve blocks are warranted.

Image quality comparison of 1.5T and 3T prostate MRIs of the same post-hip arthroplasty patients: multi-rater assessments including PI-QUAL version 2

OBJECTIVES

To compare the image quality of 1.5T and 3T prostate MRIs of the same post-hip arthroplasty patients, with a specific focus on the degree of susceptibility artifacts.

METHODS

This single-center retrospective study included post-hip arthroplasty patients who underwent 1.5T prostate MRIs between 2021 and 2023, as well as comparative 3T prostate MRIs. Three blinded abdominal radiologists retrospectively reviewed their diffusion-weighted imaging (DWI, 50 s/mm2), T2-weighted imaging (T2WI), and dynamic contrast-enhanced imaging (DCE) to evaluate the image quality. The degree of susceptibility artifacts was categorized using a three-point scale, with 3 indicating the least artifact and 1 indicating the most. Image quality was also evaluated using Prostate Imaging Quality (PI-QUAL) version 2. The median of the three raters' scores was compared between 1.5T and 3T prostate MRIs using the Wilcoxon signed-rank test. The inter-rater agreement was evaluated using the multi-rater generalized kappa.

RESULTS

Twenty pairs of 1.5T and 3T prostate MRI examinations from 20 unique patients were included. The DWI susceptibility artifact score at 1.5T was significantly higher than at 3T (mean score ± standard deviation, 2.80 ± 0.41 vs. 2.35 ± 0.93, p = 0.014). In contrast, no significant differences were observed in the susceptibility artifact scores in T2WI and DCE, or in the PI-QUAL score. The inter-reader agreement in the susceptibility artifact score was moderate (multi-rater generalized kappa: 0.60) in DWI, perfect in T2WI (not applicable), and substantial (0.65) in DCE. The inter-reader agreement was fair (0.27) in the PI-QUAL score.

CONCLUSION

Using 1.5T scanners may be preferable to reduce susceptibility artifacts from hip prostheses in DWI.

The preventive efficacy of lipid emulsion on the occurrence of local anesthetic systemic toxicity in patients receiving local infiltration analgesia for total joint arthroplasty

BACKGROUND

Motor-sparing local infiltration analgesia (LIA) enhances recovery after total hip arthroplasty (THA) and total knee arthroplasty (TKA). However, LIA can induce local anesthetic systemic toxicity (LAST), sometimes necessitating rescue lipid emulsion therapy. Our institute initiated a pilot study to pretreat patients with lipid emulsion (SMOFlipid®) to test its efficacy in mitigating LIA-induced LAST events.

METHODS

This retrospective study enrolled 1,621 adult patients who received LIA with bupivacaine (2-3 mg/kg, maximum 300 mg) for unilateral primary THA or TKA under general anesthesia between January 2020 and April 2022. A total of 439 patients received lipid pretreatment, while 1,182 did not. Demographics, surgical and anesthesia profiles, along with LAST events affecting the neurological, cardiovascular, and respiratory systems, were compared after propensity score matching for age, sex, body mass index (BMI), and surgery type.

RESULTS

The incidence of severe LAST events requiring rescue lipid emulsion slightly decreased after lipid pretreatment (from 2.54 to 2.28 per 1000). Lipid pretreatment significantly reduced the incidence of bradycardia and new-onset arrhythmia (odds ratio: 0.13, adjusted p-value: 0.024) but increased postoperative opioid requirement (odds ratio: 1.71, adjusted p-value: 0.032) after Benjamini-Hochberg correction for multiplicity.

CONCLUSIONS

The efficacy of lipid pretreatment (SMOFlipid® 1.5 ml/kg, maximum 100 ml) in mitigating LIA-induced LAST remains controversial. While lipid pretreatment reduced the incidence of new-onset arrhythmia, it showed no clear benefits for neurologic and respiratory outcomes. Additionally, lipid pretreatment might hinder postoperative recovery by increasing the need for rescue opioid analgesia. Further prospective pharmacokinetic studies are required to assess plasma bupivacaine concentrations following LIA and lipid pretreatment, examine their relationship to LAST events, and establish the efficacy and safety of lipid pretreatment.

Dual-Mobility Articulations in Revision Total Hip Arthroplasty: A Comparison with Metal or Ceramic on Highly Cross-Linked Polyethylene and Constrained Articulations

BACKGROUND

The increased availability of dual-mobility acetabular constructs (DMCs) provides surgeons with a newer option to increase the effective femoral head size in revision total hip arthroplasty (rTHA). We sought to evaluate risks of re-revision and prosthetic dislocation following rTHA involving a DMC compared with other articulations.

METHODS

A cohort study was conducted using data from a U.S. integrated health-care system's Total Joint Replacement Registry. Adult patients who underwent primary THA and went on to undergo an aseptic rTHA in 2002 to 2022 were identified. Patients who received a DMC, a constrained liner, or a metal or ceramic unipolar femoral head on highly cross-linked polyethylene (XLPE) at the time of rTHA were the treatment groups. Subsequent aseptic re-revision and dislocation were the outcomes of interest. Multivariable Cox proportional-hazards regression was used to evaluate the risks of the outcomes, with adjustment for patient, operative, and surgeon confounders.

RESULTS

The analyzed rTHAs comprised 375 with a DMC, 268 with a constrained liner, 995 with a <36-mm head on XLPE, and 2,087 with a ≥36-mm head on XLPE. DMC utilization increased from 1.0% of rTHAs in 2011 to 21.6% in 2022. In adjusted analyses, a higher re-revision risk was observed for the constrained liner (hazard ratio [HR] = 2.43, 95% confidence interval [CI] = 1.29 to 4.59), <36 mm on XLPE (HR = 2.05, 95% CI = 1.13 to 3.75), and ≥36 mm on XLPE (HR = 2.03, 95% CI = 1.19 to 3.48) groups compared with the DMC group. A higher dislocation risk was observed in both XLPE groups (<36 mm: HR = 2.04, 95% CI = 1.33 to 3.14; ≥36 mm: HR = 2.46, 95% CI = 1.69 to 3.57) compared with the DMC group; a nonsignificant trend toward a higher dislocation rate in the group with a constrained liner than in the DMC group was also observed.

CONCLUSIONS

In a large U.S.-based cohort, rTHAs using DMCs had the lowest re-revision risk and dislocation risk. Both outcomes were significantly lower than those using a unipolar femoral head on XLPE, re-revision risk was significantly lower than using a constrained liner, and dislocation risk trended toward a lower risk than using a constrained liner.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Does the Addition of a Tibial Stem Extender in Total Knee Arthroplasty Decrease Risk of Aseptic Loosening in Patients with Obesity? An Analysis from the American Joint Replacement Registry

Mechanical loosening is a leading cause of failure of total knee arthroplasties (TKAs) for which obesity may be a risk factor. With rising rates of obesity and increasing incidence of TKA, the identification of factors to mitigate this cause of failure is necessary. The purpose of this study is to determine if the use of a tibial stem extender (TSE) decreases the risk of mechanical loosening in patients with obesity undergoing TKA. The American Joint Replacement Registry and linked Centers for Medicare & Medicaid Services claims database were utilized to identify a patient cohort with a body mass index (BMI) of 30 kg/m2 or greater and age 65 years or older who underwent primary elective TKA between 2012 and 2021. Patients were divided into cohorts based on obesity class and TSE utilization. The estimated association of TSE use, BMI categories, and covariates with the risk of revisions for mechanical loosening in both unadjusted and adjusted settings was determined. Hazard ratios and their 95% confidence intervals for the risk of mechanical loosening were calculated. A total of 258,775 TKA cases were identified. A total of 538 of 257,194 (0.21%) patients who did not receive a TSE and one patient out of 1,581 (0.06%) with a TSE were revised for mechanical loosening. In adjusted analysis, TSE use was not protective against mechanical loosening and BMI > 40 was not a significant risk factor. Use of a TSE was not found to be protective against mechanical loosening in patients with obesity; however, analysis was limited by the small number of outcome events in the cohort. Further analysis with a larger cohort of patients with TSE and a longer follow-up time is necessary to corroborate this finding.

Influence of proximal femoral morphology on osteointegration of the AMIS uncemented femoral stem in modern hip arthroplasty

BACKGROUND

Indications for total hip arthroplasty (THA) have evolved over recent decades, with a growing trend toward operating on younger and more active patients. With this shift in patient demographics, there has been a change in femoral stem designs and proximal femoral morphology encountered. This study aimed to evaluate the potential correlation between femoral stem osteointegration and proximal femoral morphology using the Dorr and Noble classifications.

MATERIALS AND METHODS

We conducted a retrospective review of 122 uncemented femoral stems (AMIstem Medacta, triple tapered). The demographic data analyzed included sex, age, stem size, and surgical indications. Preoperative radiographs were reviewed to determine the Dorr classification as well as the canal-to-calcar isthmus ratio, cortical index, and canal flare index. Postoperative radiographs were carefully reviewed to identify the presence of potential postoperative radiolucencies. Inter- and intra-observer agreements for these parameters were also analyzed.

RESULTS

Significant radiolucencies (> 2 mm) were found in 19.5% of the patients. Of all the variables analyzed, the cortical index was the only parameter significantly associated with the appearance of clinically significant radiolucency, with a threshold value of 0.62.

CONCLUSIONS

The appearance of radiolucencies is multi-factorial. Nevertheless, in this study, a high cortical index (> 0.62), representing the champagne flute morphology, was found to be associated with the development of significant radiolucencies.

Big data analysis reveals significant increases in complications, costs, and hospital stay in revision total knee arthroplasty compared to primary TKA

INTRODUCTION

Despite significant advancements in total knee arthroplasty (TKA), some patients require revision surgery (R-TKA) due to complications such as infection, mechanical loosening, instability, periprosthetic fractures, and persistent pain. This study aimed to explore the specific causes leading to R-TKA, associated complications, including infection, mechanical failure, and wound issues, as well as costs, mortality rates, and hospital length of stay (LOS) using data from a large national database.

METHODS

Data from the nationwide inpatient sample (NIS), the largest publicly available all-payer inpatient care database in the United States were analysed from 1 January 2016 to 31 December 2019. The study included 44,649 R-TKA cases, corresponding to 223,240 patients, with exclusions for nonelective admissions. Various statistical analyses were used to assess clinical outcomes, including in-hospital mortality, postoperative complications, LOS, and hospitalization costs.

RESULTS

Among 2,636,880 TKA patients, 8.4% underwent R-TKA. R-TKA patients had higher rates of chronic conditions, including mental disorders (36.4%) and renal disease (9.9%). Additionally, these patients often experienced instability, necessitating revision surgery. Infection (22.3%) was the primary reason for R-TKA, followed by mechanical loosening (22.9%) and instability. Compared to primary TKA patients, R-TKA patients exhibited higher in-hospital mortality (0.085% vs. 0.025%), longer LOS (3.1 vs. 2.28 days), and higher total charges ($97,815 vs. $62,188). Postoperative complications, including blood transfusion (4.6% vs. 1.3%), acute kidney injury (4.4% vs. 1.8%), venous thromboembolism (0.55% vs. 0.29%), infection, and wound problems, were significantly higher in R-TKA patients.

CONCLUSIONS

This study provides detailed insights into t LOS, costs, and complications associated with specific etiologies of revision TKA. Our findings emphasize the need for targeted preoperative optimization and patient education. This approach can help reduce the incidence and burden of R-TKA, improve patient care, optimize resource allocation, and potentially decrease the overall rates of complications in revision surgeries.

LEVEL OF EVIDENCE

Level III.

Medical- and Implant-Related Complications Following Total Joint Arthroplasty in Patients Who Have Chronic Lymphocytic Leukemia

BACKGROUND

Chronic lymphocytic leukemia (CLL) is highly prevalent in the Total Joint Arthroplasty (TJA) age group but has not been properly evaluated. This study aims to assess: 1) 90-day medical complications; 2) implant-related complications; 3) healthcare utilization; and 4) time to revision in CLL and non-CLL TJA.

METHODS

Chronic Lymphocytic Leukemia cases undergoing total knee arthroplasty (TKA) and total hip arthroplasty (THA) were identified using diagnostic and procedural codes. CLL TKA and THA patients were matched 1:5 with controls based on demographics and comorbidities. Outcomes included 90-day medical complications, 2-year implant complications, length of stay (LOS), 90-day readmission, and time to revision.

RESULTS

The CLL TKA patients had significantly higher odds of 90-day medical complications compared to controls, notably pneumonia (OR, 9.2; CI, 7.1 to 12.0; P < 0.001) and myocardial infarction (OR, 5.5; CI, 3.9 to 7.9; P < 0.001). Similarly, CLL THA patients had greater odds of 90-day medical complications, especially pneumonia (OR 10.0; CI 8.2 to 12.2; P < 0.001) and acute kidney injury (AKI) (OR 6.3; CI 5.1 to 7.8; P < 0.001). CLL TKA patients faced higher odds of periprosthetic fracture, mechanical loosening, and prosthetic joint infection, while THA patients had increased periprosthetic fractures. Revisions occurred earlier for THA than TKA (337 ± 547 days versus 643 ± 774 days). CLL patients had longer LOS (TKA: 5.9 ± 6.5 versus 3.1 ± 1.6 days; P < 0.001) (THA: 6.3 ± 12.9 versus 3.0 ± 2.4; P < 0.001) and higher 90-day readmission rates (OR, 1.3; CI, 1.1 to 1.5, P < 0.001).

CONCLUSIONS

Orthopaedic surgeons should consider CLL status for informed patient counseling and complications mitigation.

Unbalanced metaphyseal fixation is associated with an increased aseptic loosening of revision total knee arthroplasty at mean 4-year follow-up

INTRODUCTION

The total number of total knee arthroplasty performed is rising, and the number of revisions is rising accordingly. Periprosthetic joint infection emerged in recent years as a leading cause of total knee revisions. Bone loss is a real challenge when facing septic knee revisions since radical debridement is crucial to overcome infection. Many devices have already demonstrated to reliably address bone loss and guarantee enhanced fixation. However, the role of balancing metaphyseal fixation and its interplay with the level of constraint has not been elucidated yet.

MATERIAL AND METHODS

An institutional arthroplasty registry was retrospectively reviewed looking for patients who underwent two-stage revision of the knee and metaphyseal cones implantation. Patients were divided into two groups based on the presence of cones only on one side (femoral or tibial, Group U) or both femoral and tibial side (Group B). Failure, aseptic loosening, and revision rates were compared between groups, as were values of patient-reported outcome measure. Kaplan-Meier analysis was used to assess survival of implants.

RESULTS

A total of 65 patients were included in the analysis and were evaluated at a mean final follow-up of 4 years (range, 2-7). Mean age was 67 (range, 43-81) years. Mean BMI was 27.4 (range, 20-37) kg/m2. The overall mean KSS, OKS, ROM significantly increased from baseline values to last follow-up (p < 0.001). Kaplan-Meier analysis demonstrated that patients included in Group U had a significantly lower rate of implant survival compared to those included in Group B.

CONCLUSIONS

Patients undergoing revision total knee arthroplasty for periprosthetic infection present considerable rates of complication and failure. Management of bone loss represents a concern for the surgeon, who must achieve a stable fixation. Our study demonstrated that implants characterized by an unbalanced metaphyseal fixation are at higher risk of aseptic loosening and consequent revision, especially when coupled with hinged inserts.

Characterizing diffusion-controlled release of small-molecules using quantitative MRI in view of applications to orthopedic infection

Calcium sulfate is an established carrier for localized drug delivery, but a means to non-invasively measure drug release, which would improve our understanding of localized delivery, remains an unmet need. We aim to quantitatively estimate the diffusion-controlled release of small molecules loaded into a calcium sulfate carrier through a gadobutrol-based contrast agent, which acts as a surrogate small molecule. A central cylindrical core made of calcium sulfate, either alone or within a metal scaffold, is loaded with contrast agents that release into agar. Multi-echo scans are acquired at multiple time points over 4 weeks and processed into R2* and quantitative susceptibility mapping (QSM) maps. Mean R2* values are fit to a known drug delivery model, which are then compared with the decrease in core QSM. Fitting R2* measurements of calcium sulfate core while constraining constants to a drug release model results in an R2-value of 0.991, yielding a diffusion constant of 4.59 × 10-11 m2 s-1. Incorporating the carrier within a metal scaffold results in a slower release. QSM shows the resulting loss of susceptibility in the non-metal core but is unreliable around metal. R2* characterizes the released gadobutrol, and QSM detects the resulting decrease in core susceptibility. The addition of a porous metal scaffold slows the release of gadobutrol, as expected.

Undiagnosed Periprosthetic Infections in First-Time Aseptic Revision Hip Arthroplasties

Background: Unexpected infections diagnosed after intraoperative cultures in aseptic revision hip arthroplasties are infrequent, but the features and outcomes of culture-positive cases are still poorly understood. A single-center retrospective study was conducted to assess the following: (1) the incidence, (2) the profile of the cases, and (3) the outcomes of the revision hips performed for presumed aseptic reasons that became septic after intraoperative cultures. Methods: Instances of first-time aseptic revision hips (a retrospective cohort study) in the hospital database were reviewed. The revisions with the isolation of two phenotypically identical microorganisms in the intraoperative cultures were selected. The profile (bacteria, pre-operative markers) and the outcomes of the revisions (survival rates, complications, reasons for re-revision) were assessed. Results: Out of 424 cases of presumed aseptic revision hip arthroplasty, 19 patients (4.48%) were classified as septic. Staphylococcus epidermidis (9, 47.37%) was the most frequent microorganism. In three patients (15.8%), C-reactive protein and erythrocyte sedimentation rate values were higher, and in only one case (5.26%), C-reactive protein values and the white blood cell count were elevated. An antibiotic therapy was administered in every case. At a mean follow-up of 3.72 ± 2.18 years, three patients (15.79%) experienced complications (dislocation, pain without loosening, chronic suppressive antibiotic therapy) and two patients (10.53%) required re-revision for septic relapse (same microorganisms). The survival rate of the cohort was 89.47% (95% CI: 64.08-97.26) at 2 and 4 years. Conclusions: Missed periprosthetic infections rarely occurred in presumed aseptic revision hips. However, the outcomes are fair, and septic relapses are not uncommon.

Low incidence of acute kidney injury with combined intravenous and topical antibiotic infusions in periprosthetic joint infection after total knee arthroplasty

Aims

This study aimed to assess the risk of acute kidney injury (AKI) associated with combined intravenous (IV) and topical antibiotic therapy in patients undergoing treatment for periprosthetic joint infections (PJIs) following total knee arthroplasty (TKA), utilizing the Kidney Disease: Improving Global Outcomes (KDIGO) criteria for classification.

Methods

We conducted a retrospective analysis of 162 knees (162 patients) that received treatment for PJI post-TKA with combined IV and topical antibiotic infusions at a single academic hospital from 1 January 2010 to 31 December 2022. The incidence of AKI was evaluated using the KDIGO criteria, focussing on the identification of significant predictors and the temporal pattern of AKI development.

Results

AKI was identified in 9.26% (15/162) of the cohort, predominantly presenting as stage 1 AKI, which was transient in nature and resolved prior to discharge. The analysis highlighted moderate anaemia and lower baseline serum creatinine levels as significant predictors for the development of AKI. Notably, the study found no instances of severe complications such as wound dehiscence, skin erosion, or the need for haemodialysis following treatment.

Conclusion

The findings suggest that the combined use of IV and topical antibiotic therapy in the management of PJIs post-TKA is associated with a low incidence of primarily transient stage 1 AKI. This indicates a potentially favourable renal safety profile, advocating for further research to confirm these outcomes and potentially influence treatment protocols in PJI management.

A Comparison of Clinical Outcomes After Total Knee Arthroplasty in Patients Who Have and Do Not Have Self-Reported Nickel Allergy: Matched and Unmatched Cohort Comparisons

BACKGROUND

The impact of a preoperative self-reported nickel allergy in patients undergoing primary total knee arthroplasty (TKA) remains unclear. The aim of this study was to compare the revision rates and outcomes of patients who have a self-reported nickel allergy undergoing primary TKA to patients who do not have a self-reported nickel allergy.

METHODS

Over 5 years, a total of 284 TKAs in patients who have and 17,735 in patients who do not have a self-reported nickel allergy were performed. Revision rates and differences in preoperative and postoperative patient-reported outcome measures, including Knee Osteoarthritis Outcome Score Joint Replacement (KOOS JR), Visual Analog Scale, Lower Extremity Activity Scale, and the Patient-Reported Outcomes Measurement Information System Mental and Physical Scores, were compared.

RESULTS

Survivorship free of all-cause revision at 1 year was similar for patients who have and do not have a self-reported nickel allergy (99.5% [95% CI (confidence interval): 98.6 to 100.0] versus 99.3% [95% CI: 99.1 to 99.4]), P = .49). Patients who have a self-reported nickel allergy undergoing primary TKA had no difference in KOOS JR, Visual Analog Scale, or Lower Extremity Activity Scale scores at 6 weeks and 1 year and slightly worse Patient-Reported Outcomes Measurement Information System mental and physical scores at 6 weeks compared to patients who did not have an allergy. Matched analysis revealed no difference in 6-week or 1-year KOOS, JR scores between patients who did and did not have a self-reported nickel allergy when stratified by implant class (nickel-free versus standard cobalt-chromium) (P = .113 and P = .415, respectively).

CONCLUSIONS

Patients who have a self-reported nickel allergy can be advised that, on average, their clinical outcome scores will improve similarly to patients who do not have a self-reported nickel allergy, and revision rates will be similar.

Prediction of Early Adverse Events After THA: A Comparison of Different Machine-Learning Strategies Based on 262,356 Observations From the Nordic Arthroplasty Register Association (NARA) Dataset

OBJECTIVE

Preoperative risk prediction models can support shared decision-making before total hip arthroplasties (THAs). Here, we compare different machine-learning (ML) approaches to predict the six-month risk of adverse events following primary THA to obtain accurate yet simple-to-use risk prediction models.

METHODS

We extracted data on primary THAs (N = 262,356) between 2010 and 2018 from the Nordic Arthroplasty Register Association dataset. We benchmarked a variety of ML algorithms in terms of the area under the receiver operating characteristic curve (AUROC) for predicting the risk of revision caused by periprosthetic joint infection (PJI), dislocation or periprosthetic fracture (PPF), and death. All models were internally validated against a randomly selected test cohort (one-third of the data) that was not used for training the models.

RESULTS

The incidences of revisions because of PJI, dislocation, and PPF were 0.8%, 0.4%, and 0.3%, respectively, and the incidence of death was 1.2%. Overall, Lasso regression with stable iterative variable selection (SIVS) produced models using only four to five input variables but with AUROC comparable to more complex models using all 32 variables available. The SIVS-based Lasso models based on age, sex, preoperative diagnosis, bearing couple, fixation, and surgical approach predicted the risk of revisions caused by PJI, dislocations, and PPF, as well as death, with AUROCs of 0.61, 0.67, 0.76, and 0.86, respectively.

CONCLUSION

Our study demonstrates that satisfactory predictive potential for adverse events following THA can be reached with parsimonious modeling strategies. The SIVS-based Lasso models may serve as simple-to-use tools for clinical risk assessment in the future.

Liver Disease Increases the Risk of Postoperative Complications in Patients Undergoing Aseptic Revision Total Hip and Knee Arthroplasty

Background

Due to the multiorgan effects of liver disease, surgical patients with liver disease have an increased risk of perioperative complications. With revision total hip and knee arthroplasty surgeries increasing, it is important to determine the effects of liver disease in this patient population. The purpose of this study was to evaluate the impact of underlying liver disease on postoperative outcomes following revision total joint arthroplasty (TJA).

Methods

The National Surgical Quality Improvement Program database was used to identify patients undergoing aseptic revision TJA from 2006-2019 and group them based on liver disease. The presence of liver disease was assessed by calculating the Model for End-Stage Liver Disease-Sodium score. Patients with a Model for End-Stage Liver Disease-Sodium score of > 10 were classified as having underlying liver disease. In this analysis, differences in demographics, comorbidities, and postoperative complications were assessed.

Results

Of 7102 patients undergoing revision total hip arthroplasty, 11.6% of the patients had liver disease. Of 8378 patients undergoing revision total knee arthroplasty, 8.4% of the patients had liver disease. Following adjustment on multivariable regression analysis, patients with liver disease undergoing revision total hip arthroplasty or revision total knee arthroplasty had an increased risk of major complications, wound complications, septic complications, bleeding requiring transfusion, extended length of stay, and readmission compared to those without liver disease.

Conclusions

Patients with liver disease have an increased risk of complications following revision TJA. A multidisciplinary team approach should be employed for preoperative optimization and postoperative management of these vulnerable patients to improve outcomes and decrease the incidence and severity of complications.

Level of evidence

This is retrospective cohort study and is level 3 evidence.

Evaluation of a radiological grading system for the early detection of total knee arthroplasties at risk for revision surgery

INTRODUCTION

X-rays are regularly performed after primary total knee arthroplasty (TKA). While soft tissue management and ligament tension cannot be evaluated, important information, such as inadequate component positioning and loose cement location, as well as subsequent loosening, can be detected. The aim of this study was to correlate radiological findings, referring to the radiological grading system (previously published by the same study group, henceforth abbreviated as "RGS"), with long-term outcomes and implant survival.

MATERIALS AND METHODS

A total of 266 patients who underwent titanium-coated TKA were included. In addition to implant survival, visual analogue scale score, Tegner activity score, knee society score (KSS), Western Ontario and McMaster Universities Osteoarthritis Index, and short form-12 score as well as range of motion were evaluated. Clinical examination as well as anterior-posterior, lateral, full-length weight bearing, and patellar view radiographs were performed pre- and postoperatively, at the 3-, 6-, and 12-month postoperative follow-ups and at the final follow-up. The radiological grading system was evaluated and correlated with long-term outcome and survivorship.

RESULTS

The revision-free survival rate was 88.4% at a median follow-up of 9.8 years (IQR: 9.3-10.3 years; range: 0.1-11.8 years). Revision surgery was required in 31 TKAs (11.7%). The multivariate Cox regression model showed a significant association between an RGS score ≥ 3 deviation points (DP) and an increased risk for revision (hazard ratio: 2.092; 95% CI: 1.020-4.290; p = 0.044). Moreover, the KSS for pain was significantly worse in patients with a RGS score ≥ 3 DP (median, 85 [74-92] vs. 90 [80-94]; p = 0.007).

CONCLUSIONS

This is the first study indicating that deviation in component positioning, having an inadequate long leg axis, the presence of free cement or residual bony structures on postoperative X-rays significantly correlate with TKA outcome and implant survival. Therefore RGS can be of high predicable value for the survivorship of the prosthesis.

LEVEL OF EVIDENCE

Level IV - retrospective cohort study.

A novel radiological index uses the inner canal diameter and the Citak classification index to predict risk factor for aseptic loosening following hinged total knee arthroplasty

INTRODUCTION

It remains unclear if distal femoral morphology should be a key consideration when selecting the implant or fixation strategy. A novel radiological index has been proposed to classify patients' distal femoral morphology. This study aims to evaluate the validity of this classification system in a cohort of patients undergoing hinged Total Knee Arthroplasty (TKA), and to determine if distal femoral morphology is a risk factor for aseptic loosening or all cause revision following hinged TKA.

MATERIALS AND METHODS

This study was a retrospective analysis of our institutional database. Fifty-nine patients having undergone hinged TKA with adequate radiographs for examination were eligible for inclusion. Radiographic measurements were performed using the Citak radiological index criteria. The proportion of aseptic loosening and all-cause revisions were compared between the different classification groups.

RESULTS

The analysis included 41 females (69.5%) and 18 males (30.5%). The mean age of the participants was 71.2 years (SD = 12.6). For inner canal diameter patients were classified as: Type A (31/59, 53%), Type B (19/59, 32%), and Type C (9/59, 15%). For the Index Classification Group, patients were classified as: Group A (26/59, 44%), Group B (20/59, 34%), and Group C (13/59, 22%). There was no significant difference in overall revision rate between the three groups (χ2 = 3.25, P = .197 from a Chi-square test). There was a significantly higher rate of aseptic loosening in Group C compared to Groups A and B, with no significant difference between Groups A and B in terms of aseptic loosening rates (χ2 = 8.72, P = .013 from a Chi-square test).

CONCLUSIONS

Distal femoral morphology plays an important role in the risk of aseptic loosening following hinged knee replacement, and should be considered when deciding implant type and fixation in these patients.

What are the age-related factors linked to aseptic revisions in constrained and unconstrained TKA as well as UKA? A register-based study from the German arthroplasty registry (EPRD)

PURPOSE

The implantation rate of total knee arthroplasties (TKA) is continuously growing. Aseptic problems are a major cause of revision. The aim of the following study was to determinate the incidence of aseptic revisions in primary knee arthroplasty as well as aseptic revision rates and influencing factors according to the patients' age and type of procedure.

METHODS

Data collection was performed using the German Arthroplasty Registry. Influencing factors were analyzed according to the patients' age and type of procedure. Risk factors were calculated using multiple Log-rank test with the Holm's method. Incidence and comparison of aseptic revisions according to the patients' age and type of procedure were analyzed using Kaplan-Meier-estimates. Cox regression was applied to calculate the hazard ratio.

RESULTS

Overall, 300,998 knee arthroplasties with 254,144 (84.4%) unconstrained TKA, 9,993 (3.3%) constrained TKA and 36,861 (12.3%) unicondylar knee arthroplasties (UKA) were analyzed. Patients younger than 65 years suffered a significantly higher aseptic revision rate than older patients (p < 0.0001). After one year, a revision rate of 1.1% was recorded for patients 65-74 years, 1.6% for patients under 65 years, and 1.3% for patients beyond 74 years. After seven years, patients younger than 65 years sustained in 5.0%, patients 65-74 years in 2.9% and patients beyond 74 years in 2.4% revision. In unconstrained TKA, an increased Elixhauser-score (HR = 1,75; HR = 1,54; HR = 1,7; p < 0,001) was a risk factor regardless the age. A TKA volume of 101-250 regardless the age (HR = 0,66; HR = 0,69; HR = 0,79) and > 250 under 75 years (< 65: HR = 0,72; 65-74: HR = 0,78; p = 0,001) were protective for aseptic revision. In UKA, male gender (HR = 0,81; HR = 0,72; HR = 0,57; p < 0,001), a UKA volume ≥ 51 for patients under 75 years (< 65: HR = 0,62; 65-74: HR = 0,59; p = 0,003) as well as cemented UKA for patients younger than 75 years (< 65: HR = 0,37; 65-74: HR = 0,37; p < 0,001) were detected as preventive factors.

CONCLUSION

A significant increased rate of aseptic revisions was reported for patients younger than 65 years compared to older patients. An increased Elixhauser score was a risk factor, whereas male and a high volume of performed UKA or TKA could be identified as preventive factors.

LEVEL OF EVIDENCE

III, cohort study.

Why Are Contemporary Primary Ceramic-on-Highly Crosslinked Polyethylene Total Hip Arthroplasties Failing? An Analysis of Over 5,500 Cases

BACKGROUND

Ceramic-on-highly crosslinked polyethylene (HXLPE) has become the most common bearing surface utilized in primary total hip arthroplasty (THA). The purpose of this study was to determine the implant survivorship and clinical outcomes of THAs with ceramic-on-HXLPE in a large single-institutional series.

METHODS

We identified 5,536 primary THAs performed from 2007 to 2017 using a ceramic-on-HXLPE bearing through our total joint registry. The mean age was 60 years, 51% were women, and the mean body mass index was 30. A cementless femoral component was used in 98% of cases, and a head size of ≥ 36 was used in 75%. Kaplan-Meier survivorship analyses were completed to assess survivorship free of any revision or reoperation. Clinical outcomes were assessed via Harris Hip Score. The mean follow-up was four years.

RESULTS

The 5-year survivorship free of any revision was 97%. The most common indications for revision were dislocation (41 hips), periprosthetic joint infection (39 hips), and periprosthetic femur fracture (18 hips). The 5-year survivorship free of any reoperation was 96%. There were an additional 70 reoperations, with the most common indications being wound dehiscence (32 hips), iliopsoas impingement (11 hips), and periprosthetic femur fracture (11 hips). There were only two bearing surface failures: one HXLPE liner fractured and one dissociated. There were no ceramic head fractures or failures. The mean Harris Hip Score increased from 57 to 92 (P < 0.0001).

CONCLUSIONS

In over 5,500 THAs completed with modern ceramic-on-HXLPE bearings, failures of the bearing surface were nearly eliminated at midterm follow-up, and overall 5-year survivorship free of revision was excellent. Dislocation, periprosthetic joint infection, and periprosthetic femur fracture were the most common causes of failure. As bearing surfaces have evolved, traditional failure mechanisms such as polyethylene wear, corrosion and metal reactions, and ceramic fractures have become nearly extinct.

LEVEL OF EVIDENCE

III (Case-Control Study), Therapeutic.

Long-term outcomes of acetabular impaction grafting with cemented cups and trabecular metal for revision hip arthroplasty: a follow-up study

INTRODUCTION

Revision hip arthroplasty in the presence of complex acetabular deficiencies is challenging. Cement, allograft, reconstruction rings and porous trabecular metal now provide versatile options for acetabular fixation and restoration of acetabular offset. We compare acetabular impaction bone grafting (AIBG) and trabecular metal (TM) cups at long-term follow-up.

METHODS

53 patients who underwent revision hip arthroplasty were retrospectively reviewed from local joint registry data. 36 patients were revised using AIBG and 17 with TM. Median clinical follow-up was 9.57 (2.46-18.72) years and 9.65 (7.22-12.46) years, respectively. 82% of the TM group and 63% of the AIBG group were ⩾ Paprosky 2C. Re-revision was considered failure. Radiographs demonstrating 5 mm of femoral head migration and 5° of acetabular component inclination change were considered loose.

RESULTS

Patients receiving AIBG were younger (68 vs. 74 years) with a longer interval from initial arthroplasty to revision (17 vs. 13 years). Revisions in both groups were indicated most commonly for failed cementing (AIBG 88.9% vs. TM 70.5%). No TM reconstructions underwent re-revision, with only 1 failing at 6.3 years, compared with 9 AIBG re-revisions. When revising for sepsis, 33% of AIBG revisions failed.

CONCLUSIONS

AIBG demonstrated high failure rates at long-term follow-up when compared to TM constructs. We recommend the use of AIBG in small cavitary defects only. We strongly advise against its use in the setting of significant bony defects and for prosthetic joint infection.

Does Preoperative Bisphosphonate Use Impact the Risk of Periprosthetic Fracture Following Total Hip Arthroplasty?

INTRODUCTION

Bisphosphonate (BP) use is not uncommon among total hip arthroplasty (THA) candidates. While the impact of BP therapy post-THA has been investigated, there is a paucity of literature discussing the impact of BP therapy pre-THA. Using a national dataset, we aimed to study the association between preoperative BP use and surgical outcomes in primary THA recipients.

METHODS

This retrospective cohort study utilized a commercial claims and Medicare Supplemental Databases to identify adults aged ≥ 18 who had an index non-fracture-related primary THA from 2016 to 2020. The use of BP was defined as ≥ 6 months of BP therapy in the year prior to THA. Outcomes were 90-day all-cause readmission, 90-day readmission related to periprosthetic fracture (PPF), 90-day and 1-year all-cause revision, 1-year PPF-related revision, and 1-year diagnosis of PPF. In a 1:5 propensity-score matched analysis, each THA patient who had preoperative BP use was matched to five THA patients who did not have preoperative BP use. Logistic regression models were fitted; we report odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

Of 91,907 THA patients, 1,018 (1.1%) used BP preoperatively. In the propensity-score-matched cohort (1,018 preoperative BP users, 5,090 controls), preoperative BP use was significantly associated with increased odds of 90-day all-cause revision surgery (OR 1.67; 95% CI 1.10 to 2.53; P = 0.02), 1-year PPF-related revision (OR 2.23; 95% CI 1.21 to 4.10; P = 0.01), and 1-year PPF diagnosis (OR 1.88; 95% CI 1.10 to 3.20; P = 0.02). There was no significant association between preoperative BP use and the other outcomes in the matched cohort.

CONCLUSION

These findings suggest that preoperative BP use is associated with an increased risk of revision surgery and PPF in both the short and long term. This information can help in preoperative planning and patient counseling, potentially leading to improved surgical outcomes and reduced complication rates.

What Factors Influence In-Hospital Mortality Following Aseptic Revision Total Hip Arthroplasty? A Single-Center Analysis of 13,203 Patients

BACKGROUND

Revision total hip arthroplasty (rTHA) is associated with an extended surgical period, an increased hospitalization period, expanded blood loss, and high mortality rates. The purpose of the present study was to assess the risk factors that contribute to in-hospital mortality following aseptic rTHA.

METHODS

We performed a retrospective examination of the medical records of all patients who underwent elective rTHA surgery at our tertiary referral arthroplasty center between March 1996 and March 2019. The study involved a group of 13,203 patients, including 70 who expired during hospitalization and 13,133 in the control group. Baseline characteristics, medical history, comorbidities, and surgery-related parameters of the patients were recorded. Logistic regression analyses were performed to examine the association between independent variables and in-hospital mortalities, which were presented as odds ratios (ORs) and confidence intervals (CIs).

RESULTS

Patient factors associated with in-hospital mortality included hepatitis C (OR 75.5, 95% CI 3.5 to 1,625.2), chronic obstructive pulmonary disease (OR 30.7, 95% CI 6.5 to 145.7), rheumatoid arthritis (OR 28.9, 95% CI 3.8 to 218.5), history of myocardial infarction (OR 24.9, 95% CI 4.4 to 140.8), history of cerebrovascular disease (OR 23.1, 95% CI 3.8 to 142), congestive heart failure (OR 18.9, 95% CI 3.8 to 94.2), and diabetes mellitus (OR 10.2, 95% CI 2.4 to 42.6). Surgical factors included the history of multiple prior revisions (OR 1.75, 95% CI 1.1 to 2.7), postoperative blood transfusion (OR 2.8, 95% CI 1.1 to 7.3), and decreased preoperative hemoglobin (OR 2.3, 95% CI 1.7 to 3.1).

CONCLUSIONS

Several patient-related and intraoperative factors significantly increased the risk of in-hospital mortality following aseptic rTHA. Vigilance and close perioperative monitoring are essential for patients undergoing this complex surgery.

LEVEL OF EVIDENCE

III.

A Registry Study on Acetabular Revisions Using Jumbo Cups: Do We Really Need a More Complex Revision Strategy?

BACKGROUND

The increasing global performance of total hip arthroplasty (THA) has led to a rise in revision surgeries, primarily due to cup failure, with aseptic loosening and periprosthetic infection being common causes. Various techniques and implants, including jumbo cups (JCs), manage residual bone loss post-cup removal, facilitating enhanced surface area for improved host bone contact, and osteointegration. The purpose of the study was to determine the outcomes of acetabular revision arthroplasty using JC implants over a 20-year follow-up period by reporting overall survivorships, complications leading to re-revision, and surgical strategies in re-revision.

METHODS

A cohort study based on a large regional registry was conducted, examining revision THA surgeries utilizing JCs between 2000 and 2020. The study included all the revision acetabular procedures performed with cementless JCs, identified with a diameter ≥ 62 millimeters (mm) in women or ≥ 66 mm in men. All iliac fixation cups were excluded. Data on demographics, revision surgery indications, components, fixation types, causes of failure, and reintervention strategies were collected and analyzed. A total of 541 JCs implanted from January 2000 to December 2020 were evaluated. The most common revision indications were "cup aseptic loosening" (54.5%) and "total aseptic loosening," which included both the cup and stem (32%).

RESULTS

The JC survival rates were 92.5% at 5 years, 85.8% at 10 years, and 81.5% at 15 years. Among the 70 failures, the main causes were "cup aseptic loosening" (40%), "total aseptic loosening" (17.1%), and "septic loosening" (12.8%). Revisions primarily involved acetabular cup revision surgery (54 cases), component explantation (11 cases), or insert or head revision (five cases).

CONCLUSIONS

This registry-based study of JCs in revision THA demonstrates excellent 15-year survival rates and acceptable failure rates. It supports JCs as a viable option, offering relative surgical simplicity compared to alternatives like antiprotrusion cages, bone grafts, and augments.

Safety Profile of Seven-Day Intra-articular Antibiotic Irrigation for the Treatment of Chronic Periprosthetic Joint Infection: A Prospective Randomized Phase II Comparative Study

BACKGROUND

Systemic intravenous antimicrobials yield poor outcomes during treatment of periprosthetic joint infection due to the inability to obtain minimum biofilm eradication concentrations. This study evaluated the safety of a novel method of optimized local delivery of intra-articular antibiotics (IAAs).

METHODS

This was a Phase II, multicenter, prospective randomized trial evaluating safety of a rapid (seven-day) two-stage exchange arthroplasty with IAA irrigation compared to standard two-stage exchange. The Experimental Group received irrigation using 80 mg tobramycin daily with a 2-hour soak, followed by hourly irrigation using 125 mg vancomycin with a 30-minute soak via an intramedullary irrigation device. The Control Group received an antibiotic-loaded cement spacer with vancomycin (average 8.4 g) and tobramycin (average 7.1 g, total 16 g antibiotics). Both groups received 12 weeks of systemic antibiotics following Stage 2. Safety measures included adverse events, peak vancomycin/tobramycin serum concentrations (Experimental Group), blood transfusion, and mortality. There were thirty-seven patients randomized to the Experimental Group and 39 to control. There was no difference in baseline demographics or comorbidities.

RESULTS

There were no antibiotic medication-related adverse events and 2 serious adverse events related to antibiotic instillation. Of 188 vancomycin peak measurements, 69% had detectable serum level concentrations, with all concentrations well below the maximum acceptable trough threshold of 20 μg/mL. Of the 103 tobramycin peak measurements, 45% had detectable levels, with all below the maximum acceptable peak threshold of 18 to 24 μg/mL. There was no difference in blood transfused per subject (Experimental: 655 mL versus Control: 792 mL; P = .4188). There were two (2) deaths in the Experimental Group and four (4) in the control.

CONCLUSIONS

The use of IAA is safe with minimal systemic antibiotic exposure. There was no difference in the rates or severity of serious adverse events between groups. Further research is being conducted to examine treatment efficacy.

Higher diagnostic value of next-generation sequencing versus culture in periprosthetic joint infection: A systematic review and meta-analysis

BACKGROUND

The next-generation sequencing (NGS) has developed rapidly in the past decade and is becoming a promising diagnostic tool for periprosthetic infection (PJI). However, its diagnostic value for PJI is still uncertain. The purpose of this systematic review and meta-analysis was to evaluate the diagnostic value of NGS compared to culture.

METHODS

In this systematic review and meta-analysis, electronic databases including PubMed, Embase, Cochrane Central Register of Controlled Trials, Web of Science and clinicaltrials.gov were searched for studies from inception to 12 November 2023. Diagnostic parameters, such as sensitivity, specificity, diagnostic odds ratio and area under the summary receiver-operating characteristic (SROC) curve (AUC), were calculated for the included studies. A systematic review and meta-analysis was performed.

RESULTS

A total of 22 studies with 2461 patients were included in our study. The pooled sensitivity, specificity and diagnostic odds ratio of NGS were 87% (95% confidence interval [CI]: 83-90), 94% (95% CI: 91-96) and 111 (95% CI: 70-177), respectively. On the other hand, the pooled sensitivity, specificity and diagnostic odds ratio of culture were 63% (95% CI: 58-67), 98% (95% CI: 96-99) and 93 (95% CI: 40-212), respectively. The SROC curve for NGS and culture showed that the AUCs are 0.96 (95% CI: 0.94-0.98) and 0.82 (95% CI: 0.79-0.86), respectively.

CONCLUSION

This systematic review and meta-analysis found NGS had higher sensitivity and diagnostic accuracy but slightly lower specificity than culture. Based on the pooled results, we suggested NGS may have the potential to be a new tool for the diagnosis of PJI.

LEVEL OF EVIDENCE

Level IV.

Short-term Comparison of Survivorship and Functional Outcomes for Metaphyseal Cones with Short and Long Stems in Revision Total Knee Arthroplasty

Printed porous titanium metaphyseal cones have become a mainstay for managing bone loss in revision total knee arthroplasty (rTKA). A short or long stem is routinely used when implanting a cone to augment fixation and offload stresses. This retrospective analysis compared the short-term survivorships and functional outcomes for use of a short or long stem with a metaphyseal cone.A total of 179 cases using metaphyseal cones and stems with median follow-up of 1.95 years (interquartile range, 1.00-2.14) were compared based on stem type. There were 55 cases with long stem(s) and 124 cases with short stem(s). Cases with both long and short stems were excluded. Demographics, Kaplan-Meier survivorships, and preoperative and 1-year postoperative patient-reported outcome measures (PROMs; 2011 Knee Society Score [KSS] objective knee score, function, and satisfaction scores; EuroQol five-dimension scale; and Short Form Survey Physical Component Summary and Mental Component Summary scores) were compared using t-tests with a significance level of α = 0.05. There were no significant differences in body mass index (mean ± standard deviation) or sex (men [%]) between the short and long stem cohorts (32.3 ± 5.3, 36.3% and 31.5 ± 5.5, 38.2%, respectively; p > 0.05). Patients who had short stems were younger (65.9 ± 8.8 vs. 69.0 ± 9.4, p = 0.0323).Revision-free survivorship for the femoral or tibial component was 100% for long stems and 98.2% for short stems at 1 and 2 years, respectively (log-rank p = 0.6330). The two revisions in the short group were for infection, thus the survivorship for aseptic loosening was 100% at 2 years for both cohorts. There were no significant differences in preoperative or postoperative PROMs.This study demonstrated that highly porous printed metaphyseal cones provided rTKA with excellent early survivorship and similar PROMs whether a short or long stem was used. Additional studies will be needed to discern longer term differences.

Should All Patients Receive Extended Oral Antibiotic Prophylaxis? Defining Its Role in Patients Undergoing Primary and Aseptic Revision Total Joint Arthroplasty

BACKGROUND

Prior studies have demonstrated reduced periprosthetic joint infection (PJI) rates following extended oral antibiotics (EOAs) for high-risk patients undergoing primary total joint arthroplasty (TJA). This study compared 3-month PJI rates in all patients undergoing primary or aseptic revision TJA with or without EOA prophylaxis.

METHODS

In total, 2,982 consecutive primary (n = 2,677) and aseptic revision (n = 305) TJAs were performed by a single, fellowship-trained arthroplasty surgeon from 2016 to 2022 were retrospectively reviewed. Beginning January 2020, all patients received 7 days of 300 mg oral cefdinir twice daily immediately postoperatively. Rates of PJI at 3 months were compared between patients who received or did not receive EOA.

RESULTS

Rates of PJI at 3 months in patients undergoing primary and aseptic revision TJA were significantly lower in those receiving EOA prophylaxis compared to those who did not (0.41 versus 1.13%, respectively; P = .02). After primary TJA, lower PJI rates were observed with EOA prophylaxis utilization (0.23 versus 0.74%, P = .04; odds ratio [OR] 3.85). Following aseptic revision TJA, PJI rates trended toward a significant decrease with the EOA compared to without (1.88 versus 4.83%, respectively; P = .16; OR 2.71).

CONCLUSIONS

All patients undergoing primary or aseptic revision TJA who received EOA prophylaxis were 3.85 and 2.71 times less likely, respectively, to develop PJI at 3 months compared to those without EOA. Future studies are needed to determine if these results are maintained at postoperative time periods beyond 3 months following primary TJA.

LEVEL OF EVIDENCE

III, Retrospective review.

Intrawound Vancomycin Powder in Primary Total Hip Arthroplasty: A Prospective Quality Control Study

BACKGROUND

The purpose of this retrospective analysis of a prospective quality control project was to determine whether the use of intrawound vancomycin powder (IVP) decreases the rate of periprosthetic joint infection (PJI) within 90 days following primary total hip arthroplasty (THA).

METHODS

From October 2021 to September 2022, a prospective quality control project was undertaken in which 10 high-volume THA surgeons alternated between using and not using IVP each month while keeping other perioperative protocols unchanged. A retrospective analysis of the project was performed to compare the group of patients who received IVP to the group of patients who did not. The primary outcome was a culture positive infection within 90 days following primary THA. Secondary outcomes included gram-positive culture, overall reoperation rate, wound complications, readmission, and wound complications within 90 days post-operatively. A total of 1,193 primary THA patients were identified for analysis. There were 523 (43.8%) patients who received IVP and were included in the IVP group, while 670 (56.2%) did not and were included in the non-IVP group. Age, body mass index, and sex were similar between the 2 groups (P > .25).

RESULTS

The IVP group had a higher rate of culture positive joint infections (1.7 [0.8, 3.2] versus 0.3% [0.04, 1.1], P = .01) than the non-IVP group. All PJI's were found to have gram positive bacteria in both groups. The IVP group had a higher overall reoperation rate than the non-IVP group (6.1 [4.2, 8.5] versus 2.4% [1.4, 3.9], P < .01). The IVP group had a higher reoperation rate for any wound complication compared to non-IVP patients (2.7 [1.5, 4.5] versus 0.7% [0.2, 1.7], P < .01). The overall readmission rate (6.1 [4.2, 8.5] versus 2.8% [1.7, 4.4], P < .01), as well as readmission for suspected infection (2.1 [1.1, 3.7] versus 0.6% [0.02, 1.5], P = .03), were higher in the IVP group.

CONCLUSIONS

The use of IVP in primary THA was associated with a higher rate of PJI, overall reoperation, reoperation for wound complications, and readmission in a prospective quality control project. Until future prospective randomized studies determine the safety and efficacy of IVP in THA conclusively, we advocate against its utilization.

The Impact of Cardiac Arrhythmias on Total Knee Arthroplasty Outcomes

BACKGROUND

Cardiac comorbidities are common in patients undergoing total knee arthroplasty (TKA). While there is an abundance of research showing an association between cardiac abnormalities and poor postoperative outcomes, relatively little is published on specific pathologies. The aim of this study was to assess the impact of cardiac arrhythmias on postoperative outcomes in the setting of TKA.

METHODS

This retrospective cohort study included all patients undergoing TKA from a national database, from 2016 to 2019. Patients who had cardiac arrhythmias were identified via International Classification of Diseases, Tenth Revision, and Clinical Modification/Procedure Coding System codes and served as the cohort of interest. Multivariate regression was performed to compare postoperative outcomes. Gamma regression was performed to assess length of stay and total charges, while negative binomial regression was used to assess 30-day readmission and reoperation. Patient demographic variables and comorbidities, measured via the Elixhauser comorbidity index, were controlled in our regression analysis. Out of a total of 1,906,670 patients, 224,434 (11.76%) had a diagnosed arrhythmia and were included in our analyses.

RESULTS

Those who had arrhythmias had greater odds of both medical (odds ratio [OR] 1.52; P < .001) and surgical complications (OR 2.27; P < .001). They also had greater readmission (OR 2.49; P < .001) and reoperation (OR 1.93; P < .001) within 30 days, longer hospital stays (OR 1.07; P < .001), and greater total charges (OR 1.02; P < .001).

CONCLUSIONS

Cardiac arrhythmia is a common comorbidity in the TKA population and is associated with worse postoperative outcomes. Patients who had arrhythmias had greater odds of both medical and surgical complications requiring readmission or reoperation.

STUDY DESIGN

Level III; Retrospective Cohort Study.

Are current rates of uncemented fixation in total hip arthroplasty supported by the literature? An update on the uncemented paradox

The optimal fixation method in total hip arthroplasty (THA) remains controversial. Initial concerns related to the long-term performance of cement fixation as well as cement disease led to the development of cementless implants, and registry data has indicated that the use of this type of fixation has increased in recent years. However, data from these same registries has not shown any improvement in outcomes when compared to cement fixation. On the contrary, while similar outcomes are seen when comparing these fixation types in younger patients (<70 years of age), cementless fixation has shown increased implant failure and revision rates in elderly patients (>70 years of age). Given the increased projected volume of THA in the United States over the next decade, it is important to utilise available data to make clinical decisions that minimise not only individual patient harm, but also the burden on the healthcare system itself. This review provides an overview of currently available outcomes data comparing cement and cementless fixation, as well as an updated analysis of current trends in fixation use in THA. We furthermore provide a comprehensive technique guide to help surgeons optimise cement fixation of the femoral component for THA and hemiarthroplasty.

The CCJR® Charles A. Engh, Sr, MD. Excellence in Hip Research Award: The Evolution of Revision Hip Arthroplasty and Impact on the Trainee's Experience

BACKGROUND

Advances in total hip arthroplasty (THA) have resulted in evolving revision indications and intraoperative techniques, which can influence the exposure of trainees to complex cases. We report 3 decades of revision experience from a tertiary referral center that trains fellows, comparing the reasons for revision and the complexity of revisions over time.

METHODS

We retrospectively reviewed all revision THAs performed at our institution from 1990 to 2022. Revision diagnoses, components revised, types of revision implants used, and exposure techniques were collected. A "complex" revision was defined as a case that involved an extended trochanteric osteotomy, triflange and cup-cage construct, or acetabular augment.

RESULTS

A total of 3,556 THA revisions were identified (108 revisions/year). Aseptic loosening was the most common indication in 1990 to 1999 (45 per year), but decreased to 28.3/year in 2010 to 2019. From 1990 to 1999 and 2010 to 2019, fracture increased from 3.1 to 7.3 per year, infection from 2.9/year to 16.9/year, and metallosis from 0.1 to 13.2 per year. Both component revision were common from 1990 to 1994 (42.6 per year), while polyethylene exchange was most common in 2010 to 2019 (43.3 per year). A decrease was observed in "complex" cases over time: 14.8 extended trochanteric osteotomies/year in 2000 to 2004 compared to 5.4 per year in 2018 to 2022, 4.5 triflange and cup-cage constructs/year in 2004 to 2007 compared to 0.8 per year in 2018 to 2022, and 4 acetabular augments per year in 2009 to 2012 compared to 1 per year in 2018 to 2022.

CONCLUSIONS

Indications for revision have changed over the decades, while the number of "complex" revisions has gradually decreased, presumably due to advances in implants and materials. If this trend extends to other training institutions, the next generation of arthroplasty surgeons will have less exposure to complex revisions during their training.

Revision Hip Arthroplasty Performed by Fellowship-Trained Versus Non-Fellowship-Trained Surgeons: A Comparison of Perioperative Management and Complications

BACKGROUND

Successful revision hip arthroplasty (rTHA) requires major resource allocation and a surgical team adept at managing these complex cases. The purpose of this study was to compare the results of rTHA performed by fellowship-trained and non-fellowship-trained surgeons.

METHODS

A national administrative database was utilized to identify 5,880 patients who underwent aseptic rTHA and 1,622 patients who underwent head-liner exchange for infection by fellowship-trained and non-fellowship-trained surgeons from 2010 to 2020 with a 5-year follow-up. Postoperative opioid and anticoagulant prescriptions were compared among surgeons. Patients treated by fellowship-trained and non-fellowship-trained surgeons had propensity scores matched based on age, sex, comorbidity index, and diagnosis. The 5-year surgical complications were compared using descriptive statistics. Multivariable analysis was performed to determine the odds of failure following head-liner exchange when performed by a fellowship-trained versus non-fellowship-trained surgeon.

RESULTS

Aseptic rTHA patients treated by fellowship-trained surgeons received fewer opioids (132 versus 165 milligram morphine equivalents per patient) and nonaspirin anticoagulants (21.4 versus 32.0%, P < .001). Fellowship-training was associated with lower dislocation rates (9.9 versus 14.2%, P = .011), fewer postoperative infections, and fewer periprosthetic fractures and re-revisions (15.2 versus 21.3%, P < .001). Head-liner exchange for infection performed by fellowship-trained surgeons was associated with lower odds of failure (31.2 versus 45.7%, odds ratio 0.76, 95% confidence interval 0.62 to 0.91, P < .001).

CONCLUSIONS

rTHA performed by adult reconstruction fellowship-trained surgeons results in fewer re-revisions in aseptic cases and head-liner exchanges. Variations in resources, volumes, and perioperative protocols may account for some of the differences.

The James A. Rand Young Investigator's Award: Keeping It Simple: Are all Musculoskeletal Infection Society Tests Useful to Diagnose Periprosthetic Joint Infection?

BACKGROUND

Current data evaluating the clinical value and cost-effectiveness of advanced diagnostic tests for periprosthetic joint infection (PJI) diagnosis, including alpha-defensin and synovial C-reactive protein (CRP), is conflicting. This study aimed to evaluate the adequacy of preoperative and intraoperative PJI workups without utilizing these tests.

METHODS

This retrospective analysis identified all patients who underwent revision total knee or hip arthroplasty (rTKA and rTHA, respectively) for suspected PJI between 2018 and 2020 and had a minimum follow-up of 2 years. Perioperative data and lab results were collected, and cases were dichotomized based on whether they met the 2018 Musculoskeletal Infection Society (MSIS) criteria for PJI. In total, 204 rTKA and 158 rTHA cases suspected of PJI were reviewed.

RESULTS

Nearly 100% of the cases were categorized as "infected" for meeting the 2018 MSIS criteria without utilization of alpha-defensin or synovial CRP (rTKA: n = 193, 94.6%; rTHA: n = 156, 98.7%). Most cases were classified as PJI preoperatively by meeting either the major MSIS or the combinational minor MSIS criteria of traditional lab tests (rTKA: n = 177, 86.8%; rTHA: n = 143, 90.5%). A subset of cases was classified as PJI by meeting combinational preoperative and intraoperative MSIS criteria (rTKA: 16, 7.8%; rTHA: 13, 8.2%). Only 3.6% of all cases were considered "inconclusive" using preoperative and intraoperative data.

CONCLUSIONS

Given the high rate of cases satisfying PJI criteria during preoperative workup using our available tests, the synovial alpha-defensin and synovial CRP tests may not be necessary in the routine diagnostic workup of PJI. We suggest that the primary PJI workup process should be based on a stepwise algorithmic approach with the most economical testing necessary to determine a diagnosis first. The use of advanced, commercialized, and costly biomarkers should be utilized only when traditional testing is indeterminate.

J-shaped association of operation duration and blood transfusion risk in patients undergoing primary total knee arthroplasty

PURPOSE

Blood transfusion is a common perioperative complication of primary total knee arthroplasty (TKA) that can lead to adverse outcomes, prolonged hospital stays, and increased medical costs. The purpose of our study was to explore the risk factors for blood transfusion and to establish whether operation duration is independently related to blood transfusion risk in patients undergoing primary TKA after adjusting for other covariates.

METHODS

This was a secondary analysis of data from a retrospective cohort study involving patients who underwent primary TKA in Singapore. The patients' baseline data, comorbidity, and surgical characteristics were collected. The independent variable was operation duration and the dependent variable was blood transfusion events. Patients were divided into three groups according to operation durations (90 and 120 min). Univariate logistic regression was used to explore the risk factors associated with blood transfusion after primary TKA. Multivariate analysis was used to assess the independent effect of operation duration on blood transfusion risk after adjusting for other covariates. Additionally, we performed subgroup analyses to identify specific groups, test the robustness of the relationships, and explore whether there were interactions between the different variables. Furthermore, restricted cubic splines (RCS) were used to identify the relationship between the two variables.

RESULTS

A total of 2,562 patients were included in the study, of whom 136 (5.61%) had a transfusion event. Operation durations were 95.55 ± 36.93 and 83.86 ± 26.29 min for blood transfused and non-transfused patients, respectively. Univariate logistic regression analysis showed that age, BMI, ASA status, Hb level, OSA, CHF, creatinine level > 2 mg/dL, and anaesthesia type were risk factors for blood transfusion. After adjusting for all covariates, multivariate logistic regression models showed that operation duration was positively associated with blood transfusion risk (odds ratio [OR] = 1.87, 95% CI = 1.174-2.933, P = 0.007). Compared to patients with an operation duration of less than 90 min, those with an operation duration of more than 120 min had a 2.141-fold increased risk of blood transfusion (OR = 2.141, 95% CI = 1.035-4.265, P = 0.035). Stratified analysis results showed that the association persisted in patients aged > 50 years, Chinese, BMI > 30 kg/m 2, Hb level > 11 g/dL, ASA status levels 2 and 3, general anaesthesia, and unilateral primary TKA. A non-linear (P-non-linear = 0.30) and J-shaped relationship was identified. The risk of transfusion increased as the operation duration decreased or exceeded the inflection point (73.2 min).

CONCLUSION

Our study demonstrated a non-linear and J-shaped relationship between operation duration and blood transfusion events in patients undergoing primary TKA. Blood transfusion risk was the lowest when the operation duration was 73.2 min. A shorter operation duration implies irregular surgical procedures and incomplete intraoperative haemostasis, leading to increased perioperative blood loss and blood transfusion. These results will be useful for clinical decision-making.

Early Versus Late Periprosthetic Joint Infection After Total Knee Arthroplasty: Do Patient Differences Exist?

BACKGROUND

Periprosthetic joint infection (PJI) is a devastating complication following total knee arthroplasty (TKA). Little evidence exists comparing those with early versus late PJI. The purpose of the study was to determine comorbidity profile differences between patients developing early and late PJI.

METHODS

There were 72,659 patients undergoing primary TKA from 2009 to 2021, who were identified from a commercial claims and encounters database. Subjects diagnosed with PJI were categorized as either 'early' (within 90 days of index procedure) or 'late' (> 2 years after index arthroplasty). Non-infected patients within these periods served as control groups following 4:1 propensity score matching on other extraneous variables. Logistic regression analyses were performed comparing comorbidities between groups.

RESULTS

Patients were significantly younger in the late compared to the early infection group (58.1 versus 62.4 years, P < .001). When compared to those with early PJI, patients who had chronic kidney disease (13.3 versus 4.1%; OR [odds ratio] 5.17, P = .002), malignancy (20.4 versus 10.5%; OR 2.53, P = .009), uncomplicated diabetes (40.8 versus 30.6%; OR 2.00, P = .01), rheumatoid arthritis (9.2 versus 3.3%; OR 2.66, P = .046), and hypertension (88.8 versus 81.6%; OR 2.17, P = .04), were all significant predictors of developing a late PJI.

CONCLUSIONS

When compared to patients diagnosed with early PJI following primary TKA, the presence of chronic kidney disease, malignancy, uncomplicated diabetes, rheumatoid arthritis, and hypertension, were independent risk factors for the development of late PJI. Younger patients who have these comorbidities may be targets for preoperative optimization interventions that minimize the risk of PJI.

Chronic Anticoagulation is Associated With Increased Risk for Postoperative Complications Following Aseptic Revision Total Hip Arthroplasty

BACKGROUND

With an aging global population, the incidence of revision total hip arthroplasty (rTHA) is expected to increase markedly. While patients undergoing primary total hip arthroplasty who require chronic anticoagulation (AC) have been associated with increased postoperative complications, less is known about the impact of chronic AC status on postoperative complications in the rTHA setting. This study sought to compare complication rates following aseptic rTHA between patients who were on chronic AC and those who were not.

METHODS

A large national database was utilized to retrospectively identify 9,421 patients who underwent aseptic rTHA between 2014 and 2019. Patients were divided into 2 cohorts: 1,790 patients (19.0%) were in the chronic AC cohort (ie, having an AC prescription filled within 6 months prior to and following rTHA), and 7,631 patients (81.0%) were not on chronic AC. Postoperative complications at 90-days and 2-years were compared between cohorts utilizing univariate and multivariate analyses, controlling for sex, age, and comorbidities.

RESULTS

At 90-days, chronic AC patients had increased odds of prosthetic joint infections (PJIs) (odds ratio [OR] 3.2, P < .001), surgical site infections (OR 3.6, P < .001), and mechanical prosthetic complications (OR 3.5, P < .001), which included any aseptic loosening, implant dislocation, or broken prosthetic. At 2-years, chronic AC patients had increased odds of PJI (OR 3.3, P < .001) as well as mechanical prosthetic complications (OR 3.2, P < .001). Chronic AC patients were also at increased risk for reoperation within 2 years after initial aseptic rTHA (OR 1.9, P < .001).

CONCLUSIONS

Patients on chronic AC have significantly higher odds of 90-day and 2-year complications after aseptic rTHA. This includes increased odds of PJI, surgical site infection, and mechanical prosthetic complications. Patients receiving chronic AC who undergo rTHA should be counseled on the risk-benefit ratio of their chronic AC status in a multidisciplinary setting to optimize their postoperative outcomes.

Tips and Tricks to Save You During Revision Total Knee Arthroplasty

The number of revision total knee arthroplasties (TKAs) performed annually continues to rise. This article is a summary of a symposium on revision TKAs presented at the 2023 American Association of Hip and Knee Surgeons annual meeting. It will provide an overview of the surgical tips and tricks for exposure and component removal, use of metaphyseal fixation and stems to manage bone loss and optimize fixation, constraint in TKA, as well as how to manage extensor mechanism disruptions with a synthetic mesh reconstruction. LEVEL OF EVIDENCE: V.

Not so Fast: Extended Oral Antibiotic Prophylaxis Does Not Reduce 90-Day Infection Rate Following Joint Arthroplasty

BACKGROUND

Periprosthetic joint infection (PJI) is a devastating complication following both total hip (THA) and knee (TKA) arthroplasty. Extended oral antibiotic (EOA) prophylaxis has been reported to reduce PJI following TJA in high-risk patients. The purpose of this study was to determine if EOA reduces PJI in all-comers and high-risk THA and TKA populations.

METHODS

This is a retrospective cohort study, including 4,576 patients undergoing primary THA or TKA at a single institution from 2018 to 2022. Beginning in 2020, EOA prophylaxis was administered for 10 days following THA or TKA at our institution. Patients were separated into 2 cohorts (1,769 EOA, 2,807 no EOA) based on whether they received postoperative EOA. The 90-day and 1-year outcomes, with a focus on PJI, were then compared between groups. A subgroup analysis of high-risk patients was also performed.

RESULTS

There was no difference in 90-day PJI rates between cohorts (EOA 1 versus no EOA 0.8%; P = .6). The difference in the rate of PJI remained insignificant at 1 year (EOA 1 versus no EOA 1%; P = .9). Similarly, our subgroup analysis of high-risk patients demonstrated no difference in postoperative PJI between EOA (n = 254) and no EOA (n = 396) (0.8 versus 2.3%, respectively; P = .2). Reassuringly, we also found no differences in the incidence of Clostridium difficile infection (EOA 0.1 versus no EOA 0.1%; P > .9) or in antibiotic resistance among those who developed PJI within 90 days (EOA 59 versus no EOA 83%; P = .2).

CONCLUSIONS

With the numbers available for analysis, EOA prophylaxis was not associated with PJI risk reduction following primary TJA when universally deployed. Furthermore, among high-risk patients, there was no statistically significant difference. While we did not identify increased antibiotic resistance or Clostridium difficile infection, we cannot recommend wide-spread adoption of EOA prophylaxis, and clarification regarding the role of EOA, even in high-risk patients, is needed.

Robotic-arm-assisted lateral unicompartmental knee arthroplasty leads to high implant survival and patient satisfaction at mean 10-year follow-up

BACKGROUND

There is a lack of literature reporting on long-term outcomes following robotic-arm-assisted lateral unicompartmental knee arthroplasty (UKA). This study assessed the long-term survivorship, patient-reported satisfaction and pain scores following robotic-arm-assisted lateral UKA for lateral compartment osteoarthritis (OA).

METHODS

A single surgeon's database was reviewed to identify all patients who underwent robotic-arm-assisted lateral UKA with a cemented, fixed-bearing prosthesis prior to May 2015. Patients were contacted to determine implant survivorship, satisfaction and pain. Kaplan-Meier models were applied to analyse survival.

RESULTS

A total of 77 knees (70 patients) with a mean follow-up of 10.2 ± 1.5 years (range: 8.1-13.3) were included. Five knees were revised, corresponding to a 10-year survivorship of 96.1% and estimated survival time of 12.7 ± 0.3 years (95% confidence interval: 12.2-13.2) with all-cause revision as the endpoint. Unexplained pain (40.0%) and progression of OA (40.0%) in contralateral compartments were the most reported reasons for revision. Among patients without revision, 94.4% were either satisfied or very satisfied with their lateral UKA and the average pain score was 1.1.

CONCLUSION

Robotic-arm-assisted lateral UKA led to high implant survivorship and patient satisfaction, and low pain scores at long-term follow-up. Progression of OA in contralateral compartments and unexplained pain were the most frequent reasons for revision. These findings support the continued use of robotic-arm-assisted lateral UKA for lateral compartment OA; however, its clinical value over conventional techniques remains to be established in prospective comparative studies.

LEVEL OF EVIDENCE

Therapeutic Level IV.

Contemporary Isolated Bearing Exchange for the Management of Hip Instability Following Primary Total Hip Arthroplasty

BACKGROUND

Isolated ball and liner exchanges (IBLEs) can be performed to increase hip joint stability, but historical results have been mixed due to a lack of head size options or dual mobility articulations. The purpose of this study was to evaluate the contemporary results of IBLEs in patients who have instability following primary total hip arthroplasty (THA).

METHODS

We retrospectively reviewed 65 primary THAs from 2016 to 2020 with hip instability undergoing IBLE or conversion to dual mobility articulation. There were 31 men and 34 women who had an average age of 70 years (range, 26 to 92). The mean time to revision from primary was 40.1 months (range, 1 to 120). In 52 cases, IBLE was performed using conventional bearings, while 13 hips were converted to dual mobility. Radiographic factors, including acetabular component orientation, reproduction of hip joint offset, leg lengths, and outcomes such as recurrent instability requiring subsequent revision and patient-reported outcome measure, were recorded and compared.

RESULTS

There were 12 (18.4%) hips that experienced subsequent instability and required another revision (17.3% ball and liner exchange versus 23.1% dual mobility articulation, P = .615). The mean time to rerevision for instability was 17.1 months. There were no significant differences in either acetabular component anteversion (P = .25) or restoration of hip joint offset (P = .87) in patients who required another revision for instability compared to those who did not, respectively. At 1 year, patients undergoing conventional bearing exchange reported higher Hip Dysfunction Osteoarthritis Outcome Score for Joint Replacements (P = .002) and Veterans Rand physical component (P = .023) scores compared to those who underwent a conversion to dual mobility articulation. Only age > 75 years at the time of surgery was associated with increased risk for dislocation (odds ratio 7.2, confidence interval 1.2 to 43.7, P = .032).

CONCLUSIONS

Isolated bearing exchanges for instability following THA remained at high risk for subsequent instability. Conversion to dual mobility articulations did not reduce the risk of reoperation.

Revision Arthroplasty Among Medicare Patients in the United States - Arthroplasty Surgeons are Doing More for Less

BACKGROUND

Previously documented trends of major joint arthroplasty demonstrate increasing volume and decreasing reimbursement for primary total knee and total hip arthroplasty procedures. As such, the purpose of this study was to evaluate trends in revision knee and hip arthroplasty volume and true Medicare reimbursements to physicians.

METHODS

The publicly accessible Centers for Medicare and Medicaid files were evaluated. Data were retrieved from the Part B National Summary Data File and queried for revision knee and hip arthroplasty billed to Medicare from 2000 to 2021. The total charge submitted to Medicare, Medicare reimbursement, number of revision arthroplasty surgeries performed, and average reimbursement per surgery were collected for each year. All monetary data were adjusted for inflation to 2021 dollars.

RESULTS

There were 492,360 revision total knee arthroplasty surgeries and 424,163 revision hip arthroplasty procedures billed to Medicare from 2000 to 2021. Medicare was billed a total of $919,603,674.86 for revision knee and $862,979,761.57 for revision hip arthroplasty during that time. Medicare reimbursed physicians an average of $1,499.89 per knee revision and $1,603.32 per hip revision surgery. The total volume of revision knee arthroplasty increased by 9,380 (62%) and revision hip decreased by 1,743 (9%) from the year 2000 to 2021. However, there was a decrease of average reimbursement per procedure of more than 37% ($1,987.14 to 1,254) and 39% ($2,149.87 to 1,311.17), respectively.

CONCLUSIONS

Despite a notable increase in the volume of revision total knee and stagnant revision hip arthroplasty, total billings to and reimbursements from Medicare for these procedures have not changed markedly per year. Importantly, this means that physicians are conducting more of these high-impact procedures yearly, while being reimbursed per procedure at a declining rate. This may indicate a need to re-assess billing and reimbursement rates for revision arthroplasty, in the context of the ever-increasing inflation rate.

Bispherical metal augment improved biomechanical stability in severe acetabular deficiency reconstruction: a comparative finite element analysis

BACKGROUND

This study used finite element analysis (FEA) to compare the biomechanical stability of bispherical metal augment (BA) and wedge-shaped trabecular-metal augment (TA) in different acetabular defect reconstruction models, thereby explaining the application value of this novel bispherical augment in complex hip revision.

METHODS

Three different acetabular defect pelvis models originating from three representative patients with different types of severe acetabular defects (Paprosky IIC, IIIA, and IIIB) were constructed and reconstruction with BA and TA technique was simulated. Based on the FEA models, the displacement of reconstruction implants, relative displacement of bone implants, and hemi-pelvic von Mises stress were investigated under static loads.

RESULTS

BA acquired smaller reconstruction system displacement, less relative displacement of bone implants, and lower pelvic von Mises stress than TA in all Paprosky IIC, IIIA, and IIIB defect reconstructions.

CONCLUSION

The FEA results show that BA could acquire favourable biomechanical stability in severe acetabular defect reconstruction. This technique is a reliable method in complex hip revision.

Revision Total Knee Arthroplasty Achieves Minimal Clinically Important Difference Faster Than Primary Total Knee Arthroplasty

BACKGROUND

Revision total knee arthroplasty (rTKA) remains underexplored regarding patient-reported outcome measures (PROMs), particularly in terms of time to reach minimal clinically important difference (MCID). This study addresses this gap by comparing the time to achieve MCID between primary TKA (pTKA) and rTKA patients, providing valuable insights into their recovery trajectories.

METHODS

A total of 8,266 TKAs (7,618 pTKA and 648 rTKA) were retrospectively studied in a multi-institutional arthroplasty registry. Patients who completed the patient-reported outcomes measurement information system (PROMIS) global physical, PROMIS physical function short form 10a (PF-10a), and knee injury and osteoarthritis outcome score physical function short form (KOOS-PS) questionnaires were identified by Current Procedural Terminology codes. Survival curves with and without interval censoring were utilized to evaluate the time to achieve MCID.

RESULTS

Comparing the time to achieve MCID, rTKAs were significantly faster than pTKA for PROMIS global physical (3.5 versus 3.7 months, P = 0.004) and KOOS-PS (3.3 versus 4.2 months, P < 0.001), but similar for PROMIS PF-10a (4.4 versus 4.8 months, P = 0.057). Interval censoring also showed similar trends with earlier times to achieve MCID for rTKAs for PROMIS global physical (0.6 to 0.61 versus 0.97 to 0.97 months, P = 0.009) and KOOS-PS (0.97 to 0.97 versus 1.47 to 1.47 months, P < 0.001), but not for PROMIS PF-10a (2.43 to 2.54 versus 1.90 to 1.91 months, P = 0.92).

CONCLUSIONS

The present study revealed that the time to achieve MCID was faster in patients undergoing rTKA compared to those undergoing pTKA. These findings allow surgeons to reassure preoperative rTKA patients that their recovery to a MCID postoperatively may be quicker than expected, especially when compared to their initial recovery after primary TKA.

LEVEL OF EVIDENCE

Level III.

High and Low Dosage of Vancomycin in Polymethylmethacrylate Cements: Efficacy and Mechanical Properties

INTRODUCTION

Prosthetic joint infections (PJIs) are difficult to treat and represent a significant burden to the healthcare system. Two-stage revision surgery with placement of an antibiotic-loaded cement spacer is currently the gold standard for treatment in the United States for late-onset infections. We evaluate the efficacy of varying doses of vancomycin added to antibiotic-containing acrylic cement spacers and discuss the biomechanical and antimicrobial properties of using high versus low doses of vancomycin in cement spacers in the hip and knee.

MATERIALS AND METHODS

Commercially available Copal cement containing either gentamicin and clindamycin (G + C) or gentamicin and vancomycin (G + V) was prepared with the manual addition of low (2 g) and high (6 g) doses of vancomycin. In vitro mechanical testing was then carried out according to ISO 5833 and DIN 53435, as well as inhibition zone assays against common PJI pathogens. Additionally, inhibition zone assays were conducted on two commercially available prefabricated spacers containing gentamicin: Copal Exchange G and Cemex Spacer-K.

RESULTS

In biomechanical testing, Copal G + V with the addition of 6 g of vancomycin failed to meet the ISO standard. Copal G + C and Copal G + V with low and high dosages of vancomycin were all effective against the tested pathogens and displayed constant efficacy for a duration of 42 days. High doses of vancomycin showed significantly lower mechanical stability. Moreover, Copal Exchange G showed significantly larger inhibition zones across 42 days.

DISCUSSION

While higher concentrations of vancomycin appear to improve the antimicrobial efficacy of cement, they also reduce its mechanical stability. Despite its smoother surface, the Copal Exchange G spacer exhibits large inhibition zones after 1 day and maintains consistently large inhibition zones over 6 weeks. Thus, it may be preferred for use in two-stage revision surgery.

CONCLUSION

Copal Exchange G is more effective than Cemex Spacer K against S. aureus and E. coli. The manual addition of vancomycin to cement containing double antibiotics is very effective. The influence on ISO compression is low, the ISO bending modulus is increased, and ISO bending, DIN bending, and DIN impact, are reduced.

Medicaid Reimbursement for Total Hip and Knee Arthroplasty: A State-by-State Analysis Compared With Medicare

BACKGROUND

Medicare (MCR) reimbursement for arthroplasty procedures has been declining, but little has been reported on Medicaid (MCD) reimbursement. We sought to determine MCD reimbursement rates using state MCD data for nine arthroplasty procedure codes and compare them to MCR rates.

METHODS

The Centers for Medicare & Medicaid Services physician fee schedule was used to collect MCR reimbursement rates, and state MCD fee schedules were accessed to collect MCD rates for nine procedures encompassing primary and revision hip and knee arthroplasty surgery. State MCR and MCD rates were compared to determine the mean dollar difference and dollar difference per relative value unit. A cost of living adjustment was performed using the Medicare Wage Index for each state. Coefficients of variation were calculated for each state to determine overall variability between the two systems.

RESULTS

The mean reimbursement rates for MCD were lower for eight of the nine codes used in the study. Medicaid reimbursed physicians an average of 11.3% less overall and 23.1% less when adjusted for cost of living. The amount of variability in the MCR rates was low with a consistent coefficient of variation of 0.06, but was higher in the MCD rates with a range of 0.26 to 0.29 in the unadjusted rates and 0.34 to 0.37 in the adjusted rates. There was a mean $6.73 decreased reimbursement per relative value unit for MCD procedures.

CONCLUSIONS

For the most common arthroplasty procedures, MCD reimbursed physicians less than MCR on average. MCD also demonstrated increased variability when compared to MCR rates between states.