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

Editorial: Challenges and advances in revision total joint arthroplasty

Revision total joint arthroplasty (TJA) is widely performed, and its incidence is increasing exponentially over time. Morbidity, mortality, as well as cost, both to the patient and the healthcare system, are significantly greater with revision TJA than primary TJA. Thus, efforts to minimize all-cause revision surgery are essential. In this special issue, we present articles on revision TJA epidemiology, surgical techniques, novel technology, implant design, and outcome optimization.

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.

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.

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

BACKGROUND

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 used a commercial claims and Medicare Supplemental database to identify adults aged ≥ 18 years who had an index nonfracture-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 (ORs) and 95% confidence intervals (CIs).

RESULTS

Of 91,907 THA patients, 1,018 (1.1%) used BP preoperatively. In the propensity score-matched cohort (1,018 preoperative BP users and 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 were no statistically significant associations between preoperative BP use and the other outcomes in the matched cohort.

CONCLUSIONS

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.

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.

The definition of atypical femoral fractures should include periprosthetic femoral fractures (PAFFs)

Periprosthetic hip fractures may have features of atypical femoral fractures.

PURPOSE

Atypical femoral fracture (AFF) is a rare complication of treatment with bisphosphonates (BPs) or denosumab. The American Society for Bone and Mineral Research (ASBMR) Task Force definition for AFFs excludes periprosthetic fractures. The purpose of this study was to determine prodromal symptoms, frequency, treatment, and outcomes of periprosthetic AFFs (PAFFs) in persons prescribed a BP or denosumab for osteoporosis and later diagnosed with a periprosthetic hip fracture.

METHODS

Participants were all veterans (age ≥ 50) from the VA Corporate Data Warehouse with at least one filled prescription for an oral or intravenous BP or denosumab from October 1999 through December 2022, prior to an ICD code for a periprosthetic fracture around a hip joint. Radiographs were reviewed for features of AFF. In those with a PAFF, the presence of a contralateral AFF was sought. Medical records of those with a PAFF were reviewed to identify prodromal symptoms, treatments, and outcomes.

RESULTS

Among approximately 400,000 veterans who received a BP or denosumab, there were 76 ICD-coded periprosthetic hip fractures, including one AFF. This fracture met all five ASMBR-defined AFF criteria. The PAFF, a Vancouver C cemented periprosthetic femur fracture, occurred in a man with > 7 years of BP therapy. There was no contralateral AFF. The BP was discontinued and the fracture was treated with an interlocking plate with cerclage wires. In the 12 months following PAFF, there were no infectious complications, but the fracture had a chronic nonunion.

CONCLUSION

Periprosthetic hip fractures may rarely have features of AFFs. Fracture nonunion may complicate PAFFs.

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.

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.

Prolonged incubation time unwarranted for acute periprosthetic joint infections

Current laboratory protocols for periprosthetic joint infections (PJIs) involve a standard 10- to 14-day incubation period. However, recent evidence indicates considerable variability in the time to diagnosis (TTD) between acute and chronic PJIs. TTD is also influenced by the employed culture media and sample types. Enriched liquid media, such as broths and blood culture bottles, along with sonication fluid culture, are commonly used, though their incremental benefit for PJI diagnosis remains debated. We retrospectively analyzed 187 confirmed hip and knee PJIs, each with at least three intraoperative samples. Comparison of TTD among early acute (n = 68), late acute (n = 52), and late chronic (n = 67) PJIs revealed a significant difference, particularly between late acute and late chronic infections (P < 0.004). Early acute and late acute PJIs were diagnosed within 5 days in 97.1% and 98.1% of cases, respectively, contrasting with 14 days required for 97.1% of late chronic PJIs. Enriched liquid media significantly improved species detection, especially in polymicrobial and anaerobic infections. Pediatric and anaerobic blood culture bottles demonstrated superior efficacy over thioglycolate broths for diagnostic confirmation. Sonication fluid culture was essential for confirming diagnoses in 17.6% of cases. Our findings highlight that clinical presentation, rather than time since primary arthroplasty, should guide incubation duration: both early acute and late acute PJIs can be diagnosed within 5 days. Medical microbiology laboratories should consider shorter incubation times for acute PJIs to optimize diagnostic efficiency. The use of blood culture bottles and sonication fluid culture proves invaluable for accurate PJI diagnosis.

IMPORTANCE

While molecular techniques are becoming increasingly employed, culture remains the gold standard for diagnosing periprosthetic joint infections. However, guidance for laboratory protocols is limited and highly variable. This article aims to increase diagnostic efficiency by providing concrete recommendations for medical microbiology laboratories.

Outcomes Following Direct Anterior Approach Total Hip Arthroplasty: A Contemporary Multicenter Study

BACKGROUND

The direct anterior approach (DAA) is a popular approach for primary total hip arthroplasty (THA). However, the contemporary outcomes for DAA THA need further elucidation. Therefore, we aimed to describe implant survivorship, complications, and clinical outcomes after DAA THA.

METHODS

From our multi-institutional total joint registry, 3,184 patients who had undergone 3,698 primary DAA THA between 2010 and 2019 were identified. The identified patients had a mean age of 65 years and a mean body mass index (BMI) of 29 kg/m 2 , and 53% of patients were female. The indications for revision and reoperation and the incidence of complications were collected and analyzed. Potential risk factors, including age, sex, BMI, and high-volume compared with low-volume operating surgeons, were examined. Descriptive statistics and Kaplan-Meier survivorship with Cox regression analyses were performed.

RESULTS

At 10 years following primary DAA THA, the cohort had 96% (95% confidence interval [CI], 95% to 98%) survivorship free of any revision and 94% (95% CI, 92% to 96%) survivorship free of any reoperation. The leading indications for revision were periprosthetic joint infection (PJI) (n = 24; 5-year cumulative incidence, 0.93% [95% CI, 0.6% to 1.5%]), periprosthetic fracture (n = 20; 5-year cumulative incidence, 0.62% [95% CI, 0.4% to 1.0%]), and aseptic loosening (n = 14; 11 femoral, 3 acetabular; 5-year cumulative incidence, 0.84% [95% CI, 0.5% to 1.5%]). A BMI of ≥40 kg/m 2 was found to be significantly associated with PJI (hazard ratio [HR], 6.4; p < 0.001), reoperation (HR, 3.5; p < 0.001), and nonoperative complications (HR, 2.3; p = 0.018). Survivorship free of recurrent instability was 99.6% (95% CI, 99.4% to 99.8%) at 5 and 10 years, and the cumulative incidence of revision for instability was 0.14% at 5 years.

CONCLUSIONS

In one of the largest published series to date, survivorship following DAA THA was satisfactory at early to intermediate follow-up. The leading indications for revision were PJI, periprosthetic fracture, and aseptic loosening. Instability after DAA THA was uncommon and infrequently led to revision. As a note of caution, a BMI of ≥40 kg/m 2 was identified as a risk factor for adverse outcome after DAA THA.

LEVEL OF EVIDENCE

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

Causes of Reoperations after Primary Total Hip Arthroplasty: A Retrospective Cohort Study Over 20 Years

BACKGROUND

Reoperations following total hip arthroplasty (THA) remain a major clinical challenge, with their incidence and socioeconomic burden rising despite advances in surgical techniques and prosthesis design. This study aimed to evaluate the predominant causes of reoperations following THA over two decades at a tertiary referral hospital, comparing trends between 2004 and 2013, and 2014 and 2023.

METHODS

We analyzed all reoperations performed at a tertiary referral hospital between January 2004 and December 2023. A total of 515 hips (483 patients) were included after excluding multiple reoperations on the same hip. The causes of reoperation were stratified into two time periods (2004 to 2013 and 2014 to 2023) to analyze trends. The time interval from primary THA to reoperations was also evaluated.

RESULTS

The main cause of reoperation after primary THA was aseptic loosening, accounting for 52.4% of cases, followed by infection (13.2%), periprosthetic fracture (PPF) (10.7%), wear/osteolysis (8.5%), ceramic fracture (5.8%), and instability/dislocation (5.6%). The proportion of aseptic loosening decreased significantly from 62.5 to 40.4%, while the proportions of infection, PPF, ceramic fracture, and instability/dislocation increased (P < 0.001). The causes of reoperation varied according to the time interval. Instability, PPF, and infection were early causes, and wear/osteolysis and aseptic loosening were relatively later causes of reoperations.

CONCLUSION

Aseptic loosening was the most common cause of reoperation following primary THA. However, the proportion of infection and PPF increased as a cause of reoperations, while the proportion of aseptic loosening decreased with time. Surgeons should consider that the main cause of reoperations differed according to the time interval from primary THA to reoperation.

Patient Frailty in Total Knee Arthroplasty: The Implementation of a Frailty Score Using an Electronic Medical Record

INTRODUCTION

Frailty has been associated with poor outcomes and higher costs after primary total knee arthroplasty. However, the implementation of a frailty score at a level one tertiary care facility to evaluate patient outcomes has not been well described. This study examined the retrospective implementation of the Hospital Frailty Risk Score (HFRS) and the relationship of the HFRS score with 90-day readmission, revision at any time point, and length of initial hospitalization.

METHODS

Using our relational database from our hospitals' electronic medical record system, we identified patients who were discharged following primary TKA from 2015 to 2023. The HFRS was calculated for each patient to determine frailty. Frail patients were defined as those who had an HFRS ≥ 5 and non-frail patients had an HFRS < 5. We used regression analyses to adjust for demographic confounders to evaluate the association of patient frailty (as defined by an HFRS ≥ 5) following primary TKA and patient outcomes, including 90-day readmissions, revision TKA, and length of hospital stay.

RESULTS

Frail patients had significantly higher rates of 90-day readmission (79 versus 14), revision (30 versus 11), and length of initial hospitalization (3.5 ± 3.5 versus 2.8 ± 2.3 days) (P < 0.0001). Frail patients were at increased risk of revision TKA for mechanical loosening (0.35 versus 0.045%, P < 0.05). Also, frail patients were at significantly higher risk for readmission and revision for infection compared to the non-frail cohort (1.4 versus 0.17%, P < 0.0001; 0.81 versus 0.25%, P < 0.05).

CONCLUSIONS

Frailty, measured using HFRS, is associated with increased 90-day readmission, revision, and inpatient length of stay following primary TKA. Frail patients are at significantly increased risk of infectious complications following primary TKA. This study demonstrates that the HFRS can be implemented using a common electronic medical record (EMR) and may help multidisciplinary care teams better focus preoperative optimization interventions on this high-risk cohort.

Severe acetabular bone loss management: is there still a role for titanium cages and cemented cups?

INTRODUCTION

Bone loss represents a formidable challenge in hip revision surgery. Recent advances in revision implants and the use of new materials have diminished the need for cup-cages in addressing severe acetabular bone loss, which, however, may still be indicated in certain situations. The objectives of this study are to assess survival, functional outcomes, and reasons for the failure of managing severe acetabular bone loss with titanium cages and cemented cup.

METHODS

57 patients treated with an acetabular cage and cemented cup for acetabular revision between January 2014 and July 2018 were retrospectively evaluated. Inclusion criteria comprised cup loosening with bone loss greater than IIB according to Paprosky classification, and a follow-up of at least 60 months.

RESULTS

The average age at the time of surgery was 74.8 years (SD 10.7). The acetabular bone defect according to the Paprosky classification was: type II C in 10 patients (21.7%), type III A in 21 patients (45.7%) and type III B in 15 patients (32.6%). Pelvic discontinuity was present in 35 cases (76.1%). The average follow-up during the final assessment was 78.3 months (SD 14.9). The reoperation rate was 13% (6 patients) and the complications rate was 17.4%. The survivorship of the implant was 87% at final follow-up.At the final follow-up average HHS was 89.4 ± 13.4, average WOMAC 15.7 ± 17.2, average HOOS 81.3 ± 19 and average FJS-12 83.7 ± 17.2. At the final follow-up, 32 patients (80%) showed excellent or good outcomes (HHS >80).

CONCLUSIONS

In the presence of severe bone defects, acetabular reconstruction using titanium acetabular cages and cemented UHMWPE cups remains a valid treatment option. Specifically, this acetabular reconstruction system should be favoured for elderly or low-demand patients, with the possibility of using it safely even in patients with pelvic discontinuity.

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.

Low-Energy Electron Beam Modification of Metallic Biomaterial Surfaces: Oxygen and Silicon-Rich Amorphous Carbon as a Wear-Resistant Coating

Metallic biomaterials, such as cobalt chrome molybdenum (CoCrMo), Ti-6Al-4V, and 316L stainless steel are commonly used in orthopedic implant devices. Damage modes such as corrosion and wear are associated with the use of these alloys. One solution to limit wear and corrosion damage is to apply a surface coating to the medical device. In this study, using the low-energy electron beam (LEEB) of scanning electron microscopy (SEM), we induced a highly scratch-resistant oxygen and silicon-rich amorphous carbon film to grow on each of the above metallic biomaterials. LEEB interaction with adventitious surface carbon, silicone, and oxygen deposited on the above three alloys resulted in the layered-deposition formation (LEEB-LD) of a surface coating. Coating chemistry, morphology, and nano-scratch wear properties on each of the three alloys were characterized using atomic force microscopy (AFM) scratch testing and SEM/Energy dispersive spectroscopy (EDS) analysis. We hypothesized that LEEB-LD coatings could be deposited on these three metallic biomaterials with improved tribological properties than the underlying metal substrate. First, we generated coatings on all three biomaterials and documented the coating morphology (thickness and heterogeneity) and chemistry as a function of alloy, exposure time, and scan rate with coating thicknesses generated between 5 and 50 nm after 60 min of treatment, with each factor affecting the thickness. EDS maps showed high amounts of carbon, oxygen, and silicon in the modified surface which depended on the alloy (e.g., CoCrMo and SS had similar compositions while Ti had higher oxygen in the coatings). Coated and uncoated surfaces were then subjected to diamond scratch testing in an AFM at increasing force until the coating delaminated from the surface. Scratch-depth versus load and nominal Hertzian stress were plotted for both the uncoated and coated surfaces. We found that scratch depths were 40%, 75%, and 38% smaller on CoCrMo, Ti, and SS coatings, respectively, at the peak contact stresses tested (⍺ < 0.05), indicating higher hardness and wear resistance for the coatings. These results support the hypothesis that controlled thickness LEEB-LD oxygen and silicon-rich amorphous carbon coatings can be systematically generated using low-power electron beams and that these coatings have increased tribological (scratch-resistance) properties compared to the substrate metal.

Cefazolin Alone Versus Cefazolin With Tobramycin or Gentamicin as Intraoperative Antibiotic Prophylaxis for Total Joint Arthroplasty

Background

Prosthetic joint infection is a serious complication of total knee arthroplasty (TKA) and total hip arthroplasty (THA). While cefazolin is the standard prophylactic antibiotic, some groups have considered adding aminoglycosides (gentamycin or tobramycin) to this regimen.

Methods

Adult primary THA and TKA patients were identified from 2010-2021 Q1 PearlDiver M151 database. Inclusion criteria were activity in the database ≥ 90 days postoperative and no infectious, neoplastic, or traumatic diagnoses within 90 days preoperative. Intraoperative antibiotic prophylaxis regimens were determined using Current Procedural Terminology J codes. For both THA and TKA, 2 subcohorts were created: (1) Patients who received cefazolin alone and (2) cefazolin and tobramycin or gentamicin. Differences in 90-day postoperative adverse outcomes were assessed with multivariable logistic regression controlling for age, sex, and Elixhauser Comorbidity Index. Five-year implant survival was assessed using Kaplan-Meier analysis and log-rank tests.

Results

For THA, 32,882 patients were identified, prophylactic cefazolin alone was given to 30,527 (92.8%), and cefazolin + gentamicin/tobramycin was given to 2355 (7.2%). For TKA, 119,611 patients were identified, prophylactic cefazolin alone was given to 110,469 (92.4%), and cefazolin + gentamicin/tobramycin was given to 9142 (7.6%). Overall SSI rate for THA was 1.1% and for TKA 0.8%. For both THA and TKA, antibiotic subgroups were clinically similar with regard to age, sex, and Elixhauser Comorbidity Index. On univariable and multivariable analysis, no 90-day outcomes varied significantly. Five-year implant survivals were not significantly different.

Conclusions

For THA and TKA, cefazolin alone vs cefazolin + gentamicin/tobramycin were not found to have differences in rates of perioperative adverse outcomes (including SSI/prosthetic joint infection) or 5-year revision rates.

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.

Single-Institution Experience With Nononcologic Total Femoral Replacement

Background

Revision hip and knee arthroplasty volume continues to rise, and total femur replacement (TFR) remains a key salvage option in patients with extensive bone loss. Prior research has demonstrated mixed results of this procedure, and this study aimed to characterize the outcomes of nononcologic TFR in one of the largest single-center modern series.

Methods

A retrospective analysis was conducted on 23 nononcologic TFR procedures performed on 22 patients between 2012 and 2021. Primary outcomes included TFR revision rate and indication for revision, while secondary outcomes included overall reoperation rate, complications, patient ambulatory status, and assistive device requirements.

Results

The average age at time of TFR was 65.7 years, with periprosthetic fracture (65.2%) and periprosthetic joint infection (34.8%) as predominant indications. More than half of patients (52.2%) required TFR revision, primarily due to periprosthetic joint infection (75.0%). Despite a high complication profile, only 1 patient underwent limb amputation and there was only 1 mortality during the study period. Overall, 63.6% of patients were ambulating (assisted or unassisted) at final follow-up.

Conclusions

Nononcologic TFR remains a viable limb-salvage option for patients undergoing revision arthroplasty with extensive bone loss. Despite a notable revision rate and infection risk, the majority of patients maintain or regain ambulatory function, emphasizing the procedure's role in preserving limb function. Clinicians should weigh potential complications when considering TFR, emphasizing patient counseling and risk mitigation strategies.

The Use of Highly Porous 3-D-Printed Titanium Acetabular Cups in Revision Total Hip Arthroplasty: A Systematic Review and Meta-Analysis

Background/Objectives: As the rate of revision total hip arthroplasty (THA) has risen, there has been a drive to improve the technology in the manufacturing of the implants used. One recent advance has been 3-D printing of trabecular titanium implants to improve implant stability and osteointegration. The aim of this study was to review the clinical and radiological outcomes of these acetabular implants in revision THA. Methods: A manual search of the databases of the US National Library of medicine (PubMed/MEDLINE), Embase, and the Cochrane library was performed. The following keywords of "revision total hip arthroplasty" AND "acetabulum" AND "titanium" AND "porous" were utilised. Results: In total, 106 abstracts were identified during manual search of databases. In total, 11 studies reporting 4 different implants, with a total of 597 operated joints in 585 patients were included in this review. There were 349 (59.7%) female patients, and the mean age per study ranged from 56.0 to 78.4 years. The all-cause survival rate was 95.52% (95% CI: 92.37-97.96) at a mean follow up of 3.8 years (95% CI: 2.6-5.1). The 40 cases that required re-operation included 17 (2.8%) for infection, 14 (2.3%) instability, 2 (0.3%) for shell migration and 5 (0.8%) for aseptic loosening. The most commonly used patient reported outcome measure was the Harris Hip Score with the mean post-operative score of 86.7 (95% CI: 84.3-89.1). Conclusions: Trabecular titanium acetabular implants, when used in revision THA, resulted in excellent short- to mid-term outcomes with improved hip specific outcomes and a survivorship of 95.52% over the reported follow-up period. Future prospective studies evaluating long term outcomes are needed to make comparisons between more established solutions used in revision THA.

TKA-AID: An Uncertainty-Aware Deep Learning Classifier to Identify Total Knee Arthroplasty Implants

BACKGROUND

A drastic increase in the volume of primary total knee arthroplasties (TKAs) performed nationwide will inevitably lead to higher volumes of revision TKAs in which the primary knee implant must be removed. An important step in preoperative planning for revision TKA is implant identification, which is time-consuming and difficult even for experienced surgeons. We sought to develop a deep learning algorithm to automatically identify the most common models of primary TKA implants.

METHODS

We used an institutional total joint registry to pull images and implant data for 9,651 patients (N = 111,519 images). We trained a deep learning model based on the EfficientNet architecture to identify nine different TKA systems across all common knee radiographic views. Model performance was assessed on internal held-out test set and external test set. Conformal prediction was employed to provide uncertainty estimates, and an outlier detection system alerts the user if an image is potentially outside of the model's trained expertise.

RESULTS

The average model accuracy on the held-out test set was 99.7%. The outlier detection system flagged 93% of images in the test set which were marked as outliers during a manual clean of the dataset. On the external test set, the model made one error out of 301 images. The model can process approximately 30 images/second.

CONCLUSION

We developed an automated knee implant identification tool that can classify nine different implant designs. Importantly, it works on multiple radiographic views and utilizes uncertainty quantification and outlier detection as safety mechanisms.

Trends and Epidemiology in Revision Total Hip Arthroplasty: A Large Database Study

BACKGROUND

The clinical and financial burden of revision total hip arthroplasty (rTHA) continues to grow. Therefore, further investigation is needed to characterize case volume, reason for failure, and postoperative complications. The purpose of this study was to characterize contemporary indications for and complications following rTHA.

METHODS

Patients undergoing rTHA between 2010 and 2021 were identified within the PearlDiver database. Adjusted rTHA incidence was calculated by dividing the annual rTHA volume by the annual primary total hip arthroplasty (THA) and multiplying by 100,000. Mann-Kendall trend tests were utilized to trend revision volume, etiology, and 90-day postoperative complications. A total of 225,958 rTHAs were identified.

RESULTS

The annual volume of rTHA did not change over the study period (18,871 to 15,994; P = 0.064). However, the adjusted incidence of rTHA significantly decreased (20,169.3 to 13,061.2 per 100,000 THAs; P < 0.001). The most common causes of rTHA were aseptic implant loosening (21.5%), instability (19.8%), and infection (19.1%). The adjusted incidences of revision due to infection (4,659.9 to 2,596.1 per 100,000 THAs; P < 0.001) and aseptic implant loosening (4,651.4 to 2,493.2 per 100,000 THAs; P < 0.001) decreased over time. The adjusted rate of instability (3,149.8 to 3,245.3 per 100,000 THAs; P = 0.304) did not change. Rates of post-revision deep vein thrombosis, hematoma, surgical site infection, and transfusion significantly decreased over the study period (P < 0.05), while rates of emergency department visits and readmission did not change.

CONCLUSIONS

In addition to a decreased adjusted incidence of rTHA, our analysis demonstrated a decreased incidence of infection, aseptic loosening, and various postoperative complications. However, no difference in the adjusted incidence of instability and periprosthetic fracture was seen over our study period. Continued study is necessary to further decrease the need for rTHA with a focus on the etiologies and complications that have remained unchanged.

Trajectories of Disability and Long-Term Care Utilization After Acute Health Events

Hip fractures, strokes, and heart attacks are common acute health events that can lead to long-term disability, care utilization, and unmet needs. However, such impacts, especially in the long term, are not fully understood. Using data from the Health and Retirement Study, 1992-2018, this study examines the long-term trajectories of individuals suffering such health shocks, comparing with individuals not experiencing health shocks. Hip fracture, stroke, and heart attack are confirmed to have severe implications for disability. In most cases of stroke and heart attack, informal caregivers provide the daily support needed by survivors, whereas following hip fracture, nursing home care is more relevant. These health shocks put individuals on worse trajectories of disability, care utilization, and unmet needs. There is no long-term recovery or convergence with individuals who do not suffer shocks. Unmet need is prevalent, even pre-shock and among individuals who do not experience health shocks, emphasizing the importance of preventative care measures. These findings support policy action to ensure hospitalized individuals, especially those aged 50 and above, receive rehabilitative services and other post-acute care. Furthermore, hospitalization is an event that requires the detection and addressing of unmet care needs beyond the short run.

Characterization and Potential Relevance of Randomized Controlled Trial Patient Populations in Revision Total Joint Arthroplasty: A Systematic Review

Randomized controlled trial (RCT) studies in revision total joint arthroplasty (rTJA) are essential to investigate the effectiveness of interventions. However, there has been limited research investigating how patient cohorts comprising rTJA RCT samples resemble the U.S. patient population undergoing rTJA in terms of demographic and clinical characteristics. Thus, the purpose of this systematic review was to compare the patient characteristics of rTJA RCT cohorts with the characteristics of national patient database cohorts. RCT studies for rTJA were aggregated. Patient demographics in this group were compared against Healthcare Cost and Utilization Project-National Inpatient Sample (NIS) and American College of Surgeons-National Surgical Quality Improvement Program (ACS-NSQIP) patient cohorts. Forty-six RCTs met inclusion criteria. There were 3,780 total patients across 46 RCTs. The average age of patients in the rTJA RCT cohort was 66.4 ± 9.4 while in the NIS cohort was 67.3 ± 11.1 (d = 0.08, effect size = small). The average body mass index (BMI) of the rTJA RCT cohort was 31.1 ± 5.7 while the NSQIP cohort was 31.7 ± 8.3 (d = 0.08, effect size = small). For rTJA, effect sizes for age, BMI, sex, ethnicity, smoking, and diabetes were all small or very small.Overall, the rTJA RCT patient cohort does not differ significantly compared with the general patient population undergoing rTJA. Differences in demographic and clinical characteristics between the rTJA RCT cohort and database cohorts were minimal to small, indicating that these differences are unlikely to impact clinical outcomes.

Modular dual-mobility constructs outperformed large femoral heads in 299 revision total hip arthroplasties at mid-term follow-up

Aims

The purpose of this study was to directly compare the Modular Dual Mobility (MDM) Mobile Bearing Hip System (Stryker, USA) and large femoral heads (LFHs) in revision total hip arthroplasties (THAs) at mid-term follow-up, with specific emphasis on survival free of re-revision for dislocation, any re-revision, dislocation, and the risk of metal-related complications.

Methods

We identified 299 revision THAs performed at a single tertiary care academic institution from March 2011 to July 2014. Aseptic loosening of the acetabular component (n = 65), dislocation (n = 58), and reimplantation as part of a two-stage exchange protocol (n = 57) were the most common reasons for index revision. MDM constructs were used in 123 cases, and LFHs were used in 176 cases. Mean age was 66 years (28 to 93), mean BMI was 31 kg/m2 (18 to 55), and 45% (n = 136) were female. Mean follow-up was seven years (2 to 12).

Results

The ten-year survival free of re-revision for dislocation was 99% (95% CI 95 to 100) in the MDM cohort and 91% (95% CI 84 to 96) in the LFH cohort, with a significantly increased risk of re-revision for dislocation in the LFH cohort (HR 7.1 (95% CI 1.3 to 40.8); p = 0.023). The ten-year survival free of any re-revision was 92% (95% CI 82 to 99%) in the MDM cohort and 84% (95% CI 74 to 90) in the LFH cohort with a significantly increased risk of any re-revision in the LFH cohort (HR 2.6 (95% CI 1.1 to 5.9); p = 0.024). The ten-year survival free of any dislocation was 95% (95% CI 85 to 99) in the MDM cohort and 87% (95% CI 78 to 92) in the LFH cohort with a significantly increased risk of any dislocation in the LFH cohort (HR 2.7 (95% CI 1.1 to 6.3); p = 0.028). There were no re-revisions or reoperations for metallosis or corrosion in the MDM cohort.

Conclusion

In this head-to-head comparison, revision THAs with a MDM construct safely and effectively lowered the risk of re-revision for dislocation, any re-revision, and any dislocation compared to LFH at mid-term follow-up. There were no re-revisions or reoperations for metallosis or corrosion in the MDM cohort.

Fellowship-Trained Surgeons Experience a Learning Curve Performing Revision Total Joint Arthroplasty

BACKGROUND

Revision total hip arthroplasty (rTHA) and revision total knee arthroplasty (rTKA) require considerable surgical proficiency, but are frequently delegated to the least experienced surgeons. This study examined the influence of surgeon experience on revision outcomes.

METHODS

Prospective data on confirmed aseptic rTHAs (n = 122) and rTKAs (n = 195) performed by 4 fellowship-trained surgeons in the same practice were retrospectively analyzed. Surgeons were grouped based on years in practice (inexperienced [IE] first 2 years, early experience [EE] 4 to 6 years, and senior experience [SE] 15 to 17 years). Procedure duration, estimated blood loss (EBL), and reoperation rates were compared, controlling for potential covariates.

RESULTS

Procedure durations varied based on surgeon experience for 3 of 4 rTHA diagnoses (P ≤ 0.001). Relative to the SE surgeon, procedure duration was 80.0 (95% confidence interval 61.7 to 98.4, P < 0.001) minutes longer for IE surgeons and 30.9 (95% confidence interval 17.5 to 44.3, P < 0.001) minutes longer for the EE surgeon. Procedure durations also varied based on surgeon experience for 3 of 4 rTKA diagnoses (P < 0.001), with the longest durations for IE surgeons. Procedure durations varied based on the interaction of surgeon experience, patient age, and body mass index. The EBL did not differ in rTHA based on surgeon experience (P = 0.978), but did differ for rTKA (P = 0.004). There were 25% of rTHAs performed by IE surgeons compared to 15.5% for the EE surgeon and 3.6% for the SE surgeon that underwent reoperation within a year of the index procedure (P = 0.064), with significantly more reoperations for the same indication among IE and EE surgeons (P = 0.046).

CONCLUSIONS

Complex procedures completed by less experienced surgeons may result in longer procedures, higher EBL, and more early reoperations. Study findings implicate a learning curve for revision arthroplasty that continues for several years, warranting consideration of existing patient allocation and referral patterns.

Cross-Combination Analyses of Random Forest Feature Selection and Decision Tree Model for Predicting Intraoperative Hypothermia in Total Joint Arthroplasty

BACKGROUND

In total joint arthroplasty patients, intraoperative hypothermia (IOH) is associated with perioperative complications and an increased economic burden. Previous models have some limitations and mainly focus on regression modeling. Random forest (RF) algorithms and decision tree modeling are effective for eliminating irrelevant features and making predictions that aid in accelerating modeling and reducing application difficulty.

METHODS

We conducted this prospective observational study using convenience sampling and collected data from 327 total joint arthroplasty patients in a tertiary hospital from March 4, 2023, to September 11, 2023. Of those, 229 patients were assigned to the training and 98 to the testing sets. The Chi-square, Mann-Whitney U, and t-tests were used for baseline analyses. The feature variables selection used the RF algorithms, and the decision tree model was trained on 299 examples and validated on 98. The sensitivity, specificity, recall, F1 score, and area under the curve were used to test the model's performance.

RESULTS

The RF algorithms identified the preheating time, the volume of flushing fluids, the intraoperative infusion volume, the anesthesia time, the surgical time, and the core temperature after intubation as risk factors for IOH. The decision tree was grown to 5 levels with 9 terminal nodes. The overall incidence of IOH was 42.13%. The sensitivity, specificity, recall, F1 score, and area under the curve were 0.651, 0.907, 0.916, 0.761, and 0.810, respectively. The model indicated strong internal consistency and predictive ability.

CONCLUSIONS

The preheating time, the volume of flushing fluids, the intraoperative infusion volume, the anesthesia time, the surgical time, and the core temperature after intubation could accurately predict IOH in total joint arthroplasty patients. By monitoring these factors, the clinical staff could achieve early detection and intervention of IOH in total joint arthroplasty patients.

Metallosis, Trunnionosis, and Head-stem Dissociation of the Exeter v40 Stem in a Metal-on-Metal Hip: A Unique Case

Introduction

In this article, we report a unique case of head-stem dissociation in a metal-on-metal total hip replacement which utilized an Exeter stem. Although metallosis and pseudotumor formation are well recognized complications of metal-on-metal hip replacements, head-stem dissociations are rare with few being reported in literature. To the best of our knowledge, this case report is the first to report this occurrence in an Exeter stem.

Case Report

A 76-year-old male presented to the emergency department with pain and discomfort in his left hip triggered by a twisting movement while getting into bed. The patient described a "pop" in his hip upon turning and reported mild ongoing discomfort in his left hip for the past 4 weeks before this acute presentation. X-rays and Metal artifact reduction sequence magnetic resonance image (MARS) revealed head-stem dissociation along with pseudotumor formation. The patient successfully underwent a two stage revision with no perioperative complications.

Conclusion

This case report, to the best of our knowledge, is the first to report catastrophic failure of a metal-on-metal hip caused by trunnionosis and subsequent head-stem dissociation. We report successful management of this unique case and hope to highlight the complexities and challenges associated with metal-on-metal THR. This case report is aimed at raising clinical awareness of this rare complication which requires expert management for a successful outcome.

Using three-zone flexible cones at the metaphyseal-diaphyseal junction may avoid the need for distal femoral replacement: The floating cone technique

Distal femoral replacement (DFR) with megaprostheses is a salvage revision total knee arthroplasty (rTKA) procedure indicated in cases with massive bone defects in the distal femur. As long as these implants achieve fixation only in the diaphysis, the high aseptic loosening rate reported in some series is probably related to a lack of rotational stability. Two patients with extensive distal femoral bone defects with preservation of the metaphyseal-diaphyseal junction underwent rTKA. Instead of performing a DFR with megaprostheses, partially impacted three-zone cones and standard cemented hinged implants were used with the aim of achieving better rotational stability. Both patients showed good evolution after a 12-month follow up. Clinical findings included a normal range of motion (0-100°) without any instability and preserved ability for full weight-bearing ambulation. No signs of prosthetic loosening appeared in the X-rays during follow up. To our knowledge, this was the first time a single partially anchored three-zone cone was used in massive metaphyseal femoral defects. It is an implant-dependent technique that additionally requires the preservation of the metaphyseal-diaphyseal junction, but may avoid the use of megaprostheses in some cases.

Is the natural course of perioperative laboratory testing effective in identifying wound-related complications following primary total hip arthroplasty?

INTRODUCTION

Previous study did not clarify the correlation between the natural course of perioperative blood tests and occurrence of wound-related complications, including SSI, PJI, and delayed wound healing. This study aimed to investigate whether perioperative laboratory test is effective in identifying wound-related complications after THA.

MATERIALS AND METHODS

This retrospective, single-institutional study enrolled 1072 patients who underwent primary THAs. We identified all cases of perioperative wound-related complications, including surgical site infection (SSI), periprosthetic joint infection (PJI), and delayed wound healing. First, we investigated which factors influenced perioperative wound complications using multivariate analysis. Second, we did 2:1 case-control study between no complications and complication group by matching on age, BMI, diagnosis, ASA class, Charlson comorbidity index. The results of perioperative laboratory tests were compared between two groups. Third, we investigated whether there was an effective threshold for perioperative wound complications on serum CRP and D-dimer.

RESULTS

Twenty-six cases of THA, comprising SSI in 9 hips (0.8%), PJI in 10 hips (0.9%), and 7 hips with wound delay healing (0.7%), demonstrated perioperative wound-related complications. Multivariate analysis showed that ASA class, Charlson comorbidity index, and serum CRP values in 1 week postoperatively influenced perioperative wound complications, meanwhile serum D-dimer did not show the statistical difference. After case-control matching on patient factors, the result of any blood samples did not show statistical difference in complication group. Also, no significant threshold for detecting wound-related complications was found in serum CRP and D-dimer.

CONCLUSION

The main role of perioperative blood tests is to recognize preoperative patient factors in order to early detect of perioperative wound complications. Serum CRP values in 1 week postoperatively may play a supplemental role in taking care of perioperative wound complication.

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.

Femoral stem extraction devices

INTRODUCTION

As the number of primary total hip arthroplasty (THA) procedures continues to increase, so too does the demand for revision surgery, with a 43-70% rise in revision THA anticipated by 2030. Femoral stem extraction in revision THA is particularly challenging and may lead to complications like femoral bone loss or fractures. However, increasing catalogue of femoral stems available for primary and revision THA has led technological advances in extraction devices to potentially overcome these limitations. This review aims to discuss the identification of femoral implants and the various femoral stem extraction devices currently available.

METHODS

A scoping review of current literature was conducted to explore currently available femoral extraction devices. The devices not available in literature but used in clinical practice have also been included. This review focused on the technical components, advantages, and limitations of different femoral extraction tools, including osteotomes, reciprocating saws, high-speed burrs, trephines, and extraction systems like the Watson Extraction System, Exodus Revision Hip System, Shukla Hip Universal Stem Extraction System, and DePuy Synthes Extractors.

RESULTS

Identifying femoral implants is a critical step in preoperative planning to allow for appropriate equipment to be available during revision surgery. The present review highlights that no single extraction device is universally applicable. Tools like flexible osteotomes, burrs, and trephines offer versatility but may risk bone damage. Advanced systems like the Watson Extraction System and Shukla Hip Universal Stem Extraction System provide more precise extraction, reducing the likelihood of cortical perforations and decreasing operative time.

CONCLUSIONS

Efficient femoral stem extraction in rTHA is essential for managing complications and preserving bone stock. While traditional tools remain valuable, the development of specialized extraction systems offers improved precision and efficiency. Preoperative planning, including accurate implant identification, and the selection of appropriate extraction devices are crucial for successful outcomes in revision hip arthroplasty.

The Estimated Lifetime Risk of Revision After Primary Knee Arthroplasty Is Influenced by Implant Design and Patient Age: Data From the National Joint Registries

BACKGROUND

The aim of this study was to determine the lifetime risk of revision surgery after primary knee arthroplasty (KA) according to implant choice and patient age.

METHODS

The risk of revision according to the implant type (unicondylar, unconstrained, semiconstrained, and fully constrained) was obtained from the National Joint Registry of England and Wales. Mortality risk according to age was estimated from the Scottish Arthroplasty Project (1998 to 2019). The cumulative incidence of revision and death was calculated up to 20 years. The lifetime risk was calculated as a percentage using a multiple decrement life-table methodology.

RESULTS

The lifetime risk of revision varied according to the implant, with unconstrained having the lowest risk and fully constrained and unicondylar having the highest risks, which increased with younger age. For an "average" patient aged between 65 and 69 years, the revision risks for an unconstrained (3.6%, 95% confidence interval [CI] 3.4 to 3.9), semiconstrained (7.2%, 95% CI 3.9 to 13.6), unicondylar (13.7%, 95% CI 12.4 to 15.2), and fully constrained (15.4%, 95% CI 9.2 to 25.7) total KA gradually increased. Relative to an unconstrained KA, the risk of revision for a semiconstrained implant was similar in patients aged < 65 years (relative risk < 2), whereas when this was employed in those ≥ 65 years, the relative risk was more than double (relative risk ≥ 2). Relative to an unconstrained KA, the risk of revision for a fully constrained or a unicondylar KA was more than double in patients aged < 55 years (relative risk > 2) and more than triple (relative risk ≥ 3) in patients ≥ 55 years CONCLUSION: The estimated lifetime risk of revision following KA was dependent on patient age and implant type, with fully constrained and unicondylar KA being associated with a higher lifetime revision risk. There are limitations in the data, and the indication for surgery and the reasons for revision were not assessed.

LEVEL OF EVIDENCE

III.

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

INTRODUCTION

Options for soft tissue coverage in revision total knee arthroplasty (rTKA) range from primary wound closure to complex muscle flap reconstructions. The purpose of this study was to investigate the institutional experience of wound coverage options for complex soft tissue defects in rTKA.

MATERIALS AND METHODS

77 patients undergoing rTKA with complex wound closure by a single plastic surgeon were retrospectively reviewed. The average follow-up was 30.1 months. In 18 (23.4%) patients, an intraoperative decision for primary closure was made. Fifty-nine patients (76.6%) received either a local fasciocutaneous (N = 18), a medial gastrocnemius (N = 37), a free latissimus dorsi (N = 3) or a lateral gastrocnemius flap (N = 1). Revision-free survival and complication rates were assessed and risk factors were analyzed with Cox-regression analysis.

RESULTS

Medial gastrocnemius flaps had significant lower cumulative revision-free survival rates than local fasciocutaneous flaps (P = 0.021) and primary closures (P < 0.001) (42.5% vs. 71.5% vs. 100%,respectively). Comparing the most common complex closure procedures medial gastrocnemius flaps had the highest rate of prolonged wound healing (29.7%) and infection/reinfection (40.5%). Infection-associated flap procedures had significant lower cumulative revision-free survival rates (30.5%) than non-infection associated flap procedures (62.8%,P = 0.047). A history of more than two prior surgeries (HR = 6.11,P < 0.001) and an age ≥ 65 years (HR = 0.30,P = 0.018) significantly increased the risk of revision.

CONCLUSIONS

The results of this study indicate that primary closure -if possible- should be preferred to early proactive muscle flap coverage. Even in the hands of an experienced plastic surgeon muscle flaps have high revision and complication rates. The study highlights the need to clarify flap indications and to investigate alternative approaches.

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.

Double-Butter: A Cementation Technique That Significantly Reduces Lipid Contamination of the Tibial Baseplate in Total Knee Arthroplasty

Background

Aseptic loosening is the most common aseptic failure modality following total knee arthroplasty. Recent literature suggests that the implant-cement interface is the "weak-link" in fixation and lipid contamination may drive this debonding pattern. Therefore, the purpose of this study was to determine if the "double-butter" technique would significantly decrease lipid contamination of the tibial tray.

Methods

Transparent acrylic models of 7 different tibial baseplates were created to allow for direct visualization of fluid contamination of the implant-cement interface during experimental cementation. Three cementation techniques were then employed in triplicate for each implant: coating only the tibia ("single butter") and coating of the tibia and baseplate (with and without keel included; "double-butter"). A dye was added centrally to simulate lipid contamination. After each trial, the degree of implant-cement contamination was calculated. Standard statistical analyses were conducted.

Results

With the double-butter technique, there was a significant reduction in contamination for all studied implant designs (range: 0%-7%; P < .05) and contamination was eliminated when the entire implant was coated prior to implantation. The single-butter technique resulted in contamination of 16%-43% of the tibial undersurface. There were significant differences in percent contamination between component designs (P < .05).

Conclusions

Cementation technique and implant design each influenced baseplate lipid contamination. While significant differences were noted between keel geometries, we found that the double-butter technique effectively eliminated baseplate contamination, even in the most susceptible designs in this study. We therefore advocate for the incorporation of the double-butter technique to limit lipid contamination and potentially reduce aseptic tibial loosening.

Modified Iliac Oblique for Intraoperative Evaluation of Dual-Mobility Liner Malseating

The use of dual-mobility systems in both primary and revision total hip arthroplasty for patients with concern for instability has become increasingly popular. While these systems are an effective means for combating instability, they are not without unique complications, such as liner malseating. We describe an intraoperative technique to evaluate for malseating via fluoroscopy, allowing a surgeon to identify and correct malseating intraoperatively. Reducing the incidence of liner malseating in dual-mobility total hip replacement systems could reduce overall complication rates postoperatively and presumably improve their efficacy.

Effects of antiseptic irrigation solutions on osseointegration in a cementless tibial implantation mouse model

Despite the success of standard antiseptic irrigation solutions in reducing periprosthetic joint infection (PJI) rates, there is still a need for more effective solutions. Synergistic use of povidone-iodine (PI) and hydrogen peroxide (H2O2) has shown promising results; however, the optimal solution concentration balancing bactericidal activity and osseointegration remains unknown. This study aims to evaluate the impact of these antiseptic irrigation solutions on osseointegration and the bone-implant interface strength in vivo. Forty C57BL/6 mice underwent bilateral tibial implantation surgery and were randomly allocated into three groups receiving 0.3% PI, 10% PI mixed with 3% H2O2, or saline as irrigation solutions intraoperatively. Assessments were performed on postoperative Days 1 and 28, including plain radiographs, microcomputed tomography (microCT) evaluation, histological analysis, immunohistochemistry, and biomechanical pull-out testing. No wound complications were observed. MicroCT scans revealed no differences in peri-implant trabecular bone parameters. Biomechanical pull-out testing showed no differences in the bone-implant interface strength across groups. Histological analysis indicated no differences in bone and bone marrow percentage areas among treatment groups. Immunohistochemical analysis demonstrated no differences among groups in peri-implant osteocalcin, osterix, or endomucin-positive cells. In conclusion, using either antiseptic irrigation solution showed no differences in osseointegration parameters compared to the control group, demonstrating safety and the absence of toxicity. CLINICAL RELEVANCE: Dilute 0.3% povidone-iodine and a 1:1 combination of 10% povidone-iodine mixed with 3% hydrogen peroxide can be safely used during primary and revision total joint arthroplasty without compromising osseointegration or causing wound complications.

Efficacy and safety of a diffusion-based extended-release fluticasone propionate intra-articular injection (EP-104IAR) in knee osteoarthritis (SPRINGBOARD): a 24-week, multicentre, randomised, double-blind, vehicle-controlled, phase 2 trial

BACKGROUND

Corticosteroids are among the few effective treatments for knee osteoarthritis, but short duration of action limits their utility. EP-104IAR, a long-acting formulation of fluticasone propionate for intra-articular injection, optimises the action of fluticasone propionate through novel diffusion-based extended-release technology. The SPRINGBOARD trial assessed the efficacy, safety, and pharmacokinetics of EP-104IAR in people with knee osteoarthritis.

METHODS

SPRINGBOARD was a randomised, vehicle-controlled, double-blind, phase 2 trial done at 12 research sites in Denmark, Poland, and Czech Republic. We recruited adults aged 40 years or older with primary knee osteoarthritis (Kellgren-Lawrence grade 2-3) who reported Western Ontario and McMaster Universities Osteoarthritis Arthritis Index (WOMAC) pain scores of at least 4 and no more than 9 out of 10. Participants were randomly assigned (1:1) to receive one intra-articular dose of 25 mg EP-104IAR or vehicle control. Randomisation was done via interactive web-based access to a central predefined computer-generated list with block size of six (allocated by clinical site). Participants and assessors were masked to treatment allocation. Participants were followed up for 24 weeks. The primary outcome was the difference between groups in change in WOMAC pain score from baseline to week 12, analysed in all participants who were randomly assigned and received treatment. Safety, including laboratory analyses, and pharmacokinetics from quantification of fluticasone propionate in peripheral blood were assessed in all participants who received a dose of randomly assigned treatment. A person with lived experience of knee osteoarthritis was involved in study interpretation and writing of the report. This trial is registered with ClinicalTrials.gov, NCT04120402, and the EU Clinical Trials Register, EudraCT 2021-000859-39, and is complete.

FINDINGS

Between Sept 10, 2021, and Nov 16, 2022, 1294 people were screened for eligibility, and 319 were randomly assigned to EP-104IAR (n=164) or vehicle control (n=155). One participant in the EP-104IAR group was excluded from all analyses because treatment was not administered due to an adverse event. 318 participants (135 [42%] male and 183 [58%] female, 315 [99%] White) received randomly assigned treatment and were included in the primary analysis and safety analysis (EP-104IAR, n=163; vehicle control, n=155). At week 12, least squares mean change in WOMAC pain score from baseline was -2·89 (95% CI -3·22 to -2·56) in the EP-104IAR group and -2·23 (-2·56 to -1·89) in the vehicle control group, with a between-group difference of -0·66 (-1·11 to -0·21; p=0·0044); a significant between-group difference persisted to week 14. 106 (65%) of 163 participants in the EP-104IAR group had one or more treatment-emergent adverse event compared with 89 (57%) of 155 participants in the vehicle control group. Effects on serum glucose and cortisol concentrations were minimal and transient. There were no treatment-emergent deaths or treatment-related serious adverse events. Plasma concentrations of fluticasone propionate showed a blunted initial peak with terminal half-life of approximately 18-20 weeks.

INTERPRETATION

These phase 2 results suggest that EP-104IAR has the potential to offer clinically meaningful pain relief in knee osteoarthritis for an extended period of up to 14 weeks, longer than published data for currently marketed corticosteroids. There were minimal effects on glucose and cortisol, and stable fluticasone propionate concentrations in plasma. The safety and efficacy of EP-104IAR will be further evaluated in phase 3 trials, including the possibility of bilateral and repeat dosing with EP-104IAR.

FUNDING

Eupraxia Pharmaceuticals.

TRANSLATION

For the Danish translation of the abstract see Supplementary Materials section.

Regional Periprosthetic Joint Infection Centers: The Time Has Come for a Paradigm Change in the Treatment of Periprosthetic Joint Infection

BACKGROUND

Periprosthetic joint infection (PJI) is a rare, yet devastating complication with high mortality rates, unpredictable treatment outcomes, and high costs. The purpose of this study was to determine 90-day and 1-year mortality rates at a specialized PJI center, assess the impact of delayed referral to a PJI center on outcomes, and determine the cost of PJI treatment prior to referral to a PJI center.

METHODS

A review of our institution's PJI registry was performed to identify patients who had a chronic PJI treated with a 2-stage exchange arthroplasty at our PJI Center from 2017 to 2021. Patients not referred from an external location were excluded. Mortality at 90 days and 1 year was collected. The date of infection diagnosis until the date of referral was recorded. Outcomes were documented as failure of treatment at the final clinical follow-up. The number and type of prior infection treatments were documented for each patient. The estimated cost was calculated using established PJI literature.

RESULTS

There were 172 patients (182 joints) who met inclusion criteria during this timeframe. The 90-day and 1-year mortality rates were 0 and 3.9%, respectively. There was a higher failure rate in patients referred >90 days after the diagnosis of chronic PJI (23 versus 11%, P = 0.031). The total cost of PJI treatment prior to referral for this group of patients was $6.9 million.

CONCLUSIONS

Implementation of a specialized PJI referral center leads to lower mortality rates, improved outcomes, and decreased cost for the health-care system.

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.

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.

The Epidemiology of the Revision Total Hip Arthroplasty in the United States From 2016 to 2022

Background

The number of revision total hip arthroplasties (THAs) is projected to reach 572,000 cases annually by 2030 in the United States. This may be attributed to the successes of primary THAs combined with an aging population, patients desire to remain active, and expanded indications for younger patients. Given the evolving nature of revision THAs, an epidemiological analysis of (1) etiologies; (2) demographics, including age and region; and (3) lengths of stay (LOSs) may minimize the gap between appropriate understanding and effective intervention.

Methods

From 2016 to 2022, a national, all-payer database was queried. Incidences and indications were analyzed for a total of 102,476 patients who had revision THA procedures. Patients were stratified according to etiology of failure, age, US census region, primary payor class, and mean LOS.

Results

The most common etiologies for revision THA procedures were dislocation (16.7%) and infection (12.7%), followed by periprosthetic fracture (6.9%). The largest age group was 65-74 years (30.9%), followed by >75 years (28.6%), then 55-64 (26.5%). The South had the largest total procedure cohort (36.9%), followed by the Midwest (27.5%), then the Northeast (19.7%), and the West (15.9%). The mean LOS was 4.10 days (range, 1.0-20.0).

Conclusions

Dislocation and infection remain leading indications for revision THA. These findings can properly guide surgeons toward appropriate management as well as toward active steps to minimizing these outcomes.

Total Hip Arthroplasty in Patients with Hip Osteoporosis: A Narrative Review

Osteoporosis and osteopenia can affect patients undergoing arthroplasty of the hip, which is typically recommended for patients with severe osteoarthritis or elderly patients with a femoral neck fracture. Preoperative screening for this type of bone loss could be helpful to patients and prevent poor outcomes due to the rate of underdiagnosis of osteoporosis, which can reach 73% in patients undergoing hip arthroplasty. Complications associated with low bone mineral density include periprosthetic fractures as well as an increased revision rate. Although the benefit of antiresorptive medications postoperatively has been demonstrated, when administered preoperatively, worse outcomes were reported compared to its non-usage. Surgical management is as important as pre-medication. According to general recommendations, cemented implants provide greater benefit in osteoporotic patients. However, when using cementless implants, ribbed stems, straight tapered stems, stems with medial calcar contact, and titanium-composed stems can be used to prevent periprosthetic loss of bone mineral density; however, they should not be placed in a varus position. These stems can also be coated with zoledronate and other products.

Intrawound vancomycin powder in primary total knee arthroplasty: Does it reduce early postoperative infection?

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 prosthetic joint infection (PJI) within 90-days following primary total knee arthroplasty (TKA).

METHODS

From October 2021-September 2022, a prospective quality control project was undertaken in which 10 high-volume arthroplasty surgeons alternated between using IVP and not using IVP each month. Patients who received IVP were compared to those who did not. The primary outcome was culture positive PJI within 90-days following primary total knee arthroplasty. Secondary outcomes included overall reoperation rate, wound complications, and readmission within 90-days post-operatively.

RESULTS

A total of 1,317 primary TKA patients were identified for analysis. Fifty-six and seven tenths percent (n = 747) of patients were included in the IVP group and 43.3% (n = 570) patients were included in the non-IVP group. The overall PJI rate was 0.5%. There was no difference in 90-day culture positive PJI rates between the groups (0.7% vs. 0.2%, p = 0.24). The overall reoperation rate did not differ between the IVP and non-IVP group (6.4% vs. 4.6%, p = 0.15). Reoperation for suspected infection was not statistically different by IVP administration (1.2% vs. 0.5%, p = 0.25). Additionally, there were no differences in the incidence of wound complications (p = 0.80) or readmissions (p = 0.15).

CONCLUSIONS

The overall infection rate for this cohort was low. IVP was not associated with decreased culture positive PJI, wound complications, reoperation or readmission rates. Further analysis of IVP use in TKA should be undertaken to fully determine its efficacy and safety profile.

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.

Retaining a Well-fixed Cone During Revision Total Knee Arthroplasty: Surgical Technique and Outcomes

Metaphyseal cones are frequently used in revision total knee arthroplasties (TKAs). However, during subsequent aseptic re-revisions, removing a well-fixed cone can be difficult. One innovative option is to retain the well-fixed cone and cement a new, stemmed revision component through the retained cone, yet minimal data exist on this technique. We describe a technique for retaining a well-fixed cone during re-revision TKA and report outcomes in 6 patients with 6 well-fixed metaphyseal cones. At a mean of 4 years follow-up, no retained cones with a new femoral or tibial component with stems were revised and there was no radiographic evidence of aseptic loosening. These early data suggest that retaining a well-fixed cone can be safe in re-revision TKA to minimize morbidity associated with cone removal.

Level of evidence

IV (retrospective study).