Projections and Epidemiology of Revision Hip and Knee Arthroplasty in the United States to 2040-2060

Periprosthetic osteolysis: Mechanisms and potential treatment strategies

Periprosthetic osteolysis is a common bone-related disorder that often occurs after total hip arthroplasty. The implants can cause damage to bone and bone-related cells due to mechanical stress and micromotions, resulting in the generation of a large number of wear particles. These wear particles trigger inflammation and oxidative stress in the surrounding tissues, disrupting the delicate balance maintained by osteoblasts and osteoclasts, ultimately leading to bone loss around the implant. Clinical investigations have demonstrated that Epimedium prenylflavonoids, miR-19a-3p, stem cell-derived exosomes, and certain non-PPO category pharmaceuticals have regulatory effects on bone homeostasis through distinct molecular pathways. Notably, this phenomenon reflects inherent biological rationality rather than stochastic occurrence. Extensive research has revealed that multiple natural compounds, non-coding RNAs, exosomes, and non-PPO therapeutics not only exert modulatory influences on critical pathophysiological processes including inflammatory cascades, oxidative stress responses, and tissue regeneration mechanisms, but also effectively regulate bone-related cellular functions to inhibit PPO progression. Therefore, this review comprehensively and systematically summarizes the main pathogenic mechanisms of periprosthetic osteolysis. Furthermore, it delves deeper into the research progress on the applications of currently reported natural products, ncRNAs, exosomes, and non-PPO medications in the treatment of periprosthetic osteolysis. Based on this, we hope that this paper can provide new perspectives and references for the future development of drugs targeting periprosthetic osteolysis.

Similar kinematic patterns in posterior-stabilized and condylar constrained knee prostheses in revision knee arthroplasty: a prospective cohort study

Background

The rising incidence of primary total knee arthroplasty (pTKA) is expected to lead to more revision TKAs (rTKA), which pose greater challenges and poorer outcomes, burdening both patients and healthcare systems. Knee kinematics play a key role in pTKA outcomes, but less is known about rTKA, where high-constraint implants and joint line elevation (JLE) may affect knee kinematics. The study aimed to: (1) Compare kinematic patterns between posterior-stabilized (PS) and condylar constrained (CCK) implants during open- and closed-chain exercises in rTKA; (2) Assess the impact of JLE on anteroposterior translation and post-cam engagement.

Methods

Thirty patients (19 with PS implants and 11 with CCK implants) who underwent rTKA between 2022 and 2024 were tested at a minimum six-month follow-up. Tibiofemoral kinematics during open-chain flexion-extension (FE) and closed-chain exercises (sit-to-stand (STS) and squatting (SQ)) were analyzed using fluoroscopy. (1) Kinematic patterns were compared between PS and CCK implants, focusing on AP translation, internal-external (IE) rotation, varus-valgus (VV) rotation, range of motion (ROM) and post-cam engagement. (2) Joint line elevation was defined as a ≥4 mm increase compared to the native knee on a weight-bearing radiograph, and comparisons were made between patients with and without JLE.

Results

(1) No significant differences were observed in kinematic patterns between PS and CCK implants in rTKA. (2) A JLE ≥4 mm led to instability during squatting, particularly in early- and mid-flexion, with a significantly more anterior position in the medial compartment (0-30°: p = 0.037; 30-60°: p = 0.021). Although post-cam engagement was delayed in patients with JLE, the difference was not statistically significant (p = 0.173).

Conclusion

(1) CCK implants have a kinematic pattern similar to PS implants in revision setting, supporting their use when appropriate, (2) JLE is associated with instability during squatting in early- and mid-flexion.

Are Patients' Relationships to Their Primary Contacts Associated With Postoperative Outcomes After Total Joint Arthroplasty?

BACKGROUND

Social determinants strongly influence overall health, including recovery after total joint arthroplasty (TJA). The modern electronic health record includes a list of individuals identified by patients as their primary contacts. We aimed to assess whether the relationship between patients and their documented primary contacts was associated with outcomes after TJA.

METHODS

We retrospectively reviewed primary, elective total hip arthroplasties (THAs) and total knee arthroplasties (TKAs) at a single institution from June 2011 to December 2022, and stratified patients into two groups: family (F) [familial relationships to include spouse, first, or second degree relative] or non-family (NF) [nonfamilial relationships, such as friend or neighbor] based on patient relationship to their primary emergency contact. Baseline characteristics and postoperative outcomes were compared. Binary logistic regression was utilized to assess variables associated with all-cause revision. In total, 17,520 THAs were included as follows: 16,123 (92.0%) in the F group and 1,397 (8.0%) in the NF group. Additionally, 20,397 TKAs were included as follows: 18,819 (92.3%) in the F group and 1,578 (7.7%) in the NF group.

RESULTS

For both THA and TKA patients, having a NF primary contact was independently associated with a higher risk of all-cause revision at the latest follow-up (OR [odds ratio]: 1.48 [95% CI (confidence interval): 1.05 to 2.08], P = 0.025) and (OR: 1.62 [95% CI: 1.10 to 2.38], P = 0.014), respectively. In both THA and TKA, the F group had shorter lengths of stay (P < 0.001) and was more likely to be discharged home (P < 0.001) compared to the NF group.

CONCLUSIONS

TJA patients who have a familial primary contact demonstrate better postoperative outcomes compared to those who do not have a familial contact. Awareness of social support and additional postoperative support for patients who have NF primary contacts may be warranted following TJA.

Treatment of Interprosthetic Femoral Fracture Nonunion: A Systematic Review

BACKGROUND

Interprosthetic fractures (IFs) of the femur present complex injuries associated with increased morbidity and mortality. Limited bone stock between the proximal and distal prostheses makes fracture reduction and stabilization challenging. Nonunion is a common and severe complication of IFs, often requiring multiple interventions. This systematic review aimed to identify the most successful treatment for femoral IFs and determine the overall incidence and best management strategies for IF nonunion.

METHODS

There were five electronic databases (Medline/PubMed, Scopus, Web of Science, Cochrane and EMBASE) searched for relevant studies published until July 2024. There were 35 studies that fulfilled the inclusion criteria.

RESULTS

A total of 503 patients who had 506 IFs were analyzed. The mean age was 79 years (range, 30 to 98), and 83.6% were women. The one-year mortality was 9.9% (range, 0 to 66.7). In terms of fixation options, increased frequency of nonunion was found after nonoperative treatment (50%) and retrograde intramedullary nailing (RIN) (11.1%), while after the combination of open reduction and internal fixation (ORIF) with RIN, nonunion was not observed. In the subgroup analysis of patients treated with ORIF, dynamic condylar screws (33.3%) and conventional plates (27.3%) were related to increased frequency of nonunion compared to locking compression plates (9.1%), while double plating was the most successful method (nonunion was not reported). The overall nonunion rate was 9.5%. Depending on treatment modality, the incidence of nonunion was 8.7% after ORIF and 5.5% after revision arthroplasty combined with ORIF. For the treatment of nonunion, no secondary nonunion was reported after ORIF + RIN and double plating.

CONCLUSION

For the treatment of IFs, non-locking plating and RIN were associated with higher nonunion rates, whereas double plating and ORIF + RIN were the most successful treatment options. Interprosthetic fracture nonunion was reported in 9.5% of cases, but further research is warranted to determine the most successful management approach.

Compensation Crisis: The Impact of Inflation and Declining Medicare Payments on Hip Arthroplasty Surgeons

INTRODUCTION

Despite advances in total hip arthroplasty (THA) and revision THA (rTHA), declining reimbursement rates for orthopaedic surgeons threaten financial sustainability, particularly as case complexity and demand rise. This analysis focused on changes in Medicare payments from 2006 to 2022, adjusted for inflation, to assess trends in surgeon compensation and their implications.

METHODS

Data were extracted from 2006 to 2022, utilizing Current Procedural Terminology (CPT) codes for primary THA and rTHA to assess case complexity. Medicare's Relative Value Unit (RVU) conversion factors and reimbursement rates were analyzed and adjusted for inflation using the Consumer Price Index. Key metrics, including average reimbursement per case and per minute, were calculated, along with Total Percentage Change and Compound Annual Growth Rate (CAGR). Projected reimbursement rates for 2030 were also estimated.

RESULTS

Reimbursement rates for THA procedures have considerably declined in inflation-adjusted terms since 2006. Medicare reimbursement per work Relative Value Unit (wRVU) decreased by 38%, and all five CPT codes studied exhibited negative CAGR. By 2022, average reimbursements for primary THA and rTHA had dropped by 39.69 and 34.28%, respectively. On the other hand, the hospital share of Medicare payments has increased disproportionately compared to surgeon compensation, reflecting a trend toward reduced reimbursement for surgeon effort, complexity, and time.

DISCUSSION

The findings highlight a growing disparity in surgeon compensation despite increased patient demand and procedure complexity. Declining reimbursement pressures surgeons to increase productivity and efficiency, potentially leading to higher burnout rates and reduced willingness to perform revision cases. Medicare's failure to incorporate inflation adjustments for physician payments exacerbates this issue. As the field shifts toward value-based care, addressing surgeon reimbursement is critical to sustaining high-quality patient outcomes and fair compensation.

Inherent variation in surface roughness of Selective Laser Melting (SLM) printed titanium caused by build angle changes the mechanomicrobiocidal effectiveness of nanostructures

Additively manufactured titanium implant materials are rapidly advancing prosthetics and orthopaedic devices by making them more cost-effective and customisable. However, the surface finish of materials printed via Selective Laser Melting (SLM) currently limits their integration into the medical device field. Printing parameters, such as build angle inclination, can cause variations in the surface roughness of a part, often exceeding what is suitable for implant materials. Excessive roughness can promote microbial attachment and proliferation, potentially leading to implant rejection. Nanostructuring titanium has previously demonstrated success in mitigating bacteria and fungi via a mechanomicrobiocial mechanism on traditionally flat titanium and complex SLM-made parts but its effectiveness on the inherent roughness of three-dimensional (3D) printed titanium remains unexplored. This study examines the surface roughness of 3D-Ti at three build angles (0, 40 and 90 degrees), before and after nanostructuring. Surfaces were assessed against methicillin-resistant Staphylococcus aureus (MRSA) and Candida albicans, representative antimicrobial resistant pathogens. Results showed the nanostructures were more effective against MRSA, but microbial attachment increase with steeper angles, regardless of the presence of nanostructures. This study investigates how surface roughness of 3D printed titanium substrates impacts bacterial and fungal adhesion and the resulting nanomorphology of the surface post-hydrothermal modification.

Repeat Revision Total Knee Arthroplasty Has Significantly Lower Survivorship Compared to First-Time Revisions

INTRODUCTION

Revision total knee arthroplasty (rTKA) is an increasingly common challenge for arthroplasty surgeons. Compared to first-time rTKA, re-rTKA presents additional challenges, including further compromised soft tissues and bone loss, abundant scar tissue, stemmed revision implants, and metaphyseal fixation. The goal of this study was to compare the survivorship and clinical outcomes of aseptic first-time rTKAs and re-rTKAs.

METHODS

A retrospective review of aseptic rTKAs from a single institution from 2016 to 2022 identified 850 first-time rTKAs and 178 re-rTKAs. The mean age was 67 years, 58% were women, and the mean BMI was 31. The mean operative time was longer for re-rTKAs (173 versus 160 minutes, P = 0.02), as was the hospital length of stay for the re-rTKA cohort (3.7 versus 3.2 days, P = 0.0007). Failure was defined as all-cause revision or revision for periprosthetic joint infection (PJI).

RESULTS

At 3.5 years, re-rTKAs had significantly lower survivorship free from all-cause revision than the first-time rTKA cohort (75 versus 91%, P < 0.0001). At 1.5 years, re-rTKAs had significantly lower survivorship free from revision for PJI than the first-time rTKA cohort (93 versus 98%, P = 0.003). Overall, the re-rTKA cohort had more all-cause failures (33 [19%] versus 55 [6%]; P < 0.0001) and more PJI failures (13 [7%] versus 17 [2%]; P = 0.0001). At final follow-up, the re-rTKA cohort had a significantly lower Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS JR) (62 versus 69, P = 0.01).

CONCLUSIONS

Compared to first-time rTKA, re-rTKA has significantly decreased survivorship free from all-cause revision at 3.5 years (58 versus 43%) and revision for PJI at two years (91 versus 98%). Optimization of care for rTKA patients at centers of excellence may improve the outcomes and care of these complex patients.

Measures of Clinical Meaningfulness for the Hip Disability and Osteoarthritis Outcome Score Vary by Aseptic Revision Total Hip Arthroplasty Diagnosis

BACKGROUND

Patient-reported outcome measures (PROMs) are increasingly important in assessing revision total hip arthroplasty (THA) outcomes, yet diagnosis-specific thresholds for clinical relevance remain largely undefined. This study aimed to determine diagnosis-specific minimal clinically important difference (MCID), patient-acceptable symptom state (PASS), and substantial clinical benefit (SCB) thresholds for the Hip Disability and Osteoarthritis Outcome Score (HOOS) subscales in aseptic revision THA.

METHODS

A prospective cohort of 466 patients who underwent aseptic revision THA between 2016 and 2022 was analyzed. Patients were stratified by diagnosis: aseptic loosening (n = 232), implant failure (n = 112), instability (n = 78), and periprosthetic fracture (n = 44). The HOOS-Pain, HOOS-Physical Function Short Form (PS), and HOOS-Joint Replacement (JR) scores were collected preoperatively and at a one-year follow-up. The MCID was calculated using distribution-based methods, while PASS and SCB were determined using anchor-based approaches.

RESULTS

The MCID thresholds ranged from 10.0 (aseptic loosening) to 12.9 (periprosthetic fracture) for HOOS-Pain, 9.9 (instability) to 12.9 (periprosthetic fracture) for HOOS-PS, and 8.7 (aseptic loosening) to 12.1 (periprosthetic fracture) for HOOS-JR. The PASS thresholds varied from 67.5 (implant failure) to 72.5 (periprosthetic fracture) for HOOS-Pain, 76.6 (periprosthetic fracture) to 80.0 (aseptic loosening, implant failure, and instability) for HOOS-PS, and 64.7 (aseptic loosening) to 73.5 (implant failure and instability) for HOOS-JR. The SCB thresholds spanned 15 (implant failure) to 35 (aseptic loosening) for HOOS-Pain, 4.6 (periprosthetic fracture) to 22.0 (instability) for HOOS-PS, and 16.1 (instability) to 25.9 (implant failure) for HOOS-JR.

CONCLUSION

This study established diagnosis-specific thresholds for MCID, PASS, and SCB across HOOS subscales in aseptic revision THA, demonstrating significant variability by preoperative diagnosis. Patients who have aseptic loosening showed the greatest improvement and highest likelihood of achieving clinically meaningful benefits, while those who have periprosthetic fractures and instability had lower rates of meaningful recovery. These findings provide a critical framework for outcome assessment and personalized patient counseling.

Intra-wound vancomycin powder is cost-saving in primary total hip and knee arthroplasty

PURPOSE

This study seeks to explore whether intra-wound vancomycin powder (IVP) is a cost-effective adjunct to standard of care (SOC) in patients undergoing total joint arthroplasty (TJA) from a US payor perspective.

METHODS

A decision-analytic model in the form of a decision tree was developed to compare the cost and outcomes of IVP with those of SOC in preventing periprosthetic joint infections (PJI) in TJA patients. The base case analysis assumes a hypothetical practice with an equal volume (50/50) of THA and TKA procedures in both the IVP + SOC and the SOC arm. Cost and clinical effectiveness data were obtained from published literature. Sensitivity and threshold analyses were used to estimate how changing inputs would impact the cost-effectiveness of IVP.

RESULTS

Deterministic results found that in the base case model, IVP as an adjunct to SOC generates a cost saving of $260.38/patient. In scenario analysis, where THA and TKA procedures were separated, the estimated cost saving was $241.50/patient and $279.27/patient, respectively. Break-even analysis showed that the cost of IVP per patient would need to be $244.82-$282.59, or the PJI relative risk (RR) be approximately 0.99. Probabilistic analysis found IVP + SOC was cost-saving in 99.26% of the 10,000 iterations in the base case model.

CONCLUSION

Applying local vancomycin as an adjunct to SOC in primary TJA is not just cost effective, but cost-saving in reducing PJIs, saving an average of $260.38/patient. Depending on individual institution/practice infection rates and revision surgery costs, local vancomycin administration for primary TJA should be considered.

Dual-Mobility Articulations in Primary Total Hip Arthroplasty: Mid-Term Outcomes From the American Joint Replacement Registry

BACKGROUND

In recent years, there has been an increased utilization of dual-mobility (DM) implants in primary total hip arthroplasty (THA) to mitigate the risk of postoperative hip instability. This study aimed to present mid-term outcomes of DM bearings in primary THA using data from the American Joint Replacement Registry.

METHODS

Screening was conducted on patients aged ≥ 65 years who underwent primary THA between 2012 and 2018. Patients were categorized into three groups: (1) DM articulation, (2) ≤ 32-mm femoral head, and (3) ≥ 36-mm femoral head. Multivariable statistical modeling was employed to analyze patient and hospital characteristics, minimizing potential confounding variables and identifying independent associations with revision. Cox proportional hazards regression analyses were used to assess all-cause revision and revision specifically for instability. A total of 207,526 primary THAs were identified. Among them, 13,896 (6.7%) utilized DM articulation, 60,358 (29.1%) had a femoral head size of ≤ 32 mm, and 133,272 (64.2%) had a femoral head size of ≥ 36 mm.

RESULTS

At the 8-year follow-up, the all-cause revision rate was higher in the DM group (3.5%, 95% confidence interval [CI] 3.1 to 4.1) compared to the ≤ 32-mm (2.6%, 95% CI 2.5 to 2.8) and ≥ 36-mm (2.7%, 95% CI 2.5 to 2.9) groups. However, the revision rate for instability was comparable among the DM (0.4%, 95% CI 0.2 to 0.5), ≤ 32 mm (0.5%, 95% CI 0.4 to 0.5), and ≥ 36 mm (0.3%, 95% CI 0.3 to 0.4) groups at 8-year follow-up.

CONCLUSIONS

The utilization of DM was associated with higher overall revision rates. However, no significant differences in rates of revision for instability were observed among any of the bearing surface groups. These findings may be attributed to surgeons selectively utilizing DM articulations in higher-risk patients.

Aseptic Revision Total Knee Arthroplasty in Octogenarians: A Matched Cohort Comparison of Early Clinical Outcomes

BACKGROUND

With increasing volume and life expectancy of patients undergoing total knee arthroplasty (TKA), the incidence of octogenarian patients requiring revision TKA (rTKA) will similarly rise. There remains limited evidence regarding the safety of revision procedures in octogenarians who may carry an increased risk of medical and surgical complications. Therefore, the purpose of our analysis was to evaluate early clinical outcomes following rTKA in patients aged ≥ 80 years compared with younger matched controls.

METHODS

Patients who underwent aseptic all-component rTKA between 2010 and 2020 at a multiple-surgeon, single-site institution were reviewed. Patients aged ≥ 80 years were matched to cohorts of patients aged ≥ 40 to 59 years and ≥ 60 to 79 years undergoing rTKA based on sex, American Society of Anesthesiologists score, and body mass index. Multivariate regression analysis of 90-day postoperative medical and surgical complications, controlling for comorbidity burden, smoking status, and revision etiology, was conducted. A total of 210 patients (n = 70 per cohort) were evaluated.

RESULTS

There were no differences between octogenarians and younger patients for medical (odds ratio [OR]: 0.32; 95% confidence interval [CI]: 0.053 to 1.91; P = 0.2), surgical (OR: 1.61, 95% CI: 0.42 to 6.19; P = 0.5), and overall complications (OR: 0.52, 95% CI: 0.17 to 1.60; P = 0.3) at 90 days. Octogenarians had a statistically lower risk of reoperation relative to younger controls (OR: 0.22, 95% CI: 0.054 to 0.85; P = 0.03).

CONCLUSIONS

Octogenarians undergoing rTKA had comparable early postoperative clinical outcomes compared to younger matched controls. These findings suggest that appropriately indicated octogenarians requiring all-component rTKA may safely undergo these procedures. Adult reconstruction surgeons must consider both age and comorbidity burden when counseling these patients regarding the risks associated with revision surgery.

Clinical anatomy of the inferior gluteal nerve - systematic review and meta-analysis

BACKGROUND

The variations and patterns presented by inferior gluteal nerve (IGN) have been linked to iatrogenic complications, particularly in pelvic operations. The aim of this meta-analysis was to obtain data regarding IGN morphometry, communication and relationship with nervous structures of the gluteal area, course, pattern and muscle innervation.

METHODS

A large-scale search was conducted (PubMed, Embase, Science Direct and Web of Science) with no restrictions on date or language. Included categories involved prevalence, course, patterns, origin and distances from respective anatomical landmarks.

RESULTS

A total of 20 studies (n = 1235 hemipelves) were incorporated into our publication. The distance between the main branch of IGN and the greater trochanter was 70.2 mm (95 %CI:37.9-102.5). In the mid-gluteal region, the nerve was 22.6 mm (95 %CI:11.3-33.8) away from the ischial spine. Moreover, for this study's purpose we distinguished seven morphological IGN variants, which presented different courses in regard to the piriformis muscle. The most common was type I, in which IGN went under the piriformis muscle and its prevalence equaled 90.6 % (95 %CI:83.2-98.4;p < 0.001).

CONCLUSION

Clinicians, particularly those performing hip surgeries, should be aware of the potential variations of IGN and their associated challenges, as such knowledge can help mitigate the risk of injury to this structure. The IGN's close proximity to the greater trochanter plays a crucial role in the posterior approach to the hip, as it could be used as a landmark to help prevent iatrogenic damage during this procedure.

Very High Early Failure Rate Following Primary Repair of Acute Extensor Mechanism Disruption After Total Knee Arthroplasty

BACKGROUND

Extensor mechanism disruption is a devastating complication following total knee arthroplasty (TKA). Despite its morbidity, there is no consensus regarding the optimal treatment strategy. We aimed to determine the survivorship, clinical outcomes, and improvement in patient-reported outcome measures after primary repair of acute extensor mechanism disruptions following primary or revision TKA.

METHODS

A retrospective review identified 41 acute extensor mechanism disruptions (33 primary TKAs and eight revision TKAs) from 2015 to 2021. The study group was 56% women, the mean body mass index was 33, the mean age was 66 years, and the mean follow-up was 3 years. Extensor mechanism disruption occurred at the patellar tendon (n = 17), quadriceps tendon (n = 15), and patella (n = 9) at a mean of 10 months following TKA. Surgical management was primary repair (n = 30) or primary repair with augmentation (allograft or autograft) (n = 11). Kaplan-Meier analysis estimated survivorship.

RESULTS

The 2-year survivorship free from all-cause reoperation was 72 and 23% following primary and revision TKA, respectively (P = 0.013). The 2-year survivorship free from all-cause reoperation was 66% for primary repair versus 61% for primary repair with augmentation (P = 0.95). There were 17 (41%) patients who underwent reoperation, most commonly for rerupture (n = 4) in two primary repairs and two primary repairs with augmentation (P = 0.288). Revision TKA (P = 0.049) and increased time from disruption to repair (P = 0.039) were risk factors for reoperation. Neither did the mean extensor lag significantly improve nor did patients see improvement in their patient-reported outcome measures.

CONCLUSIONS

After primary and revision TKA, acute extensor mechanism disruption treated with primary repair with or without augmentation had very poor early survivorship free from all-cause reoperation. Patients should be counseled appropriately, and alternative surgical techniques should be considered.

Recent Medicare Billing Trends of Hospitals and Surgeons for Revision Hip and Knee Total Joint Arthroplasty: Is the Value of a Surgeon's Work Decreasing?

BACKGROUND

Revision hip and knee total joint arthroplasty (TJA) is associated with higher health care costs and work burden than primary TJAs. However, previous studies demonstrated a decrease in the value of reimbursements for revision TJA, causing concerns for hospitals and surgeons regarding the financial sustainability of these resource-expensive procedures. This study aimed to investigate the Medicare billing trends of hospitals and surgeons for revision TJA between 2017 and 2022.

METHODS

Medicare claims and payments for revision TJA were identified from the Centers for Medicare and Medicaid Services Part A and B databases. Hospital claims for revision TJA were identified through Diagnostic-Related Groups (467, 468). Surgeon claims were identified using Current Procedural Terminology codes for revision hip (27134, 27137, 27138) and knee (27486, 27487) TJA. Yearly charges, reimbursements, and markup ratios (MR = charge/reimbursement) were analyzed. All monetary values were adjusted to the 2022 U.S. dollars.

RESULTS

A total of 43,125 surgeons and 152,974 hospital claims were included in this study. From 2017 to 2022, the total volume of revision TJA decreased by 19.4%. Hospital reimbursements remained relatively unchanged, with a decrease of 1.4%, while hospital charges increased by 11.8%, resulting in a 13.3% increase in the MR. For surgeons, reimbursements decreased by 13.8%, and charges decreased by 11.0%, leading to a 3.3% increase in the MR. The proportion of surgeon reimbursement to hospital reimbursement decreased from 8.5 to 7.5%.

CONCLUSIONS

The comparison of the billing trends of hospitals and surgeons showed the relatively stable value of hospital reimbursement while the value of surgeon reimbursement continued to decline, implying the decreasing fiscal value of physicians' work. The study suggests the need for sustainable financial incentives for surgeons performing revision TJA and strategies to control hospital charges to alleviate financial burdens and improve patient access to revision TJA.

Variability and clinical anatomy of the superior gluteal nerve-A systematic review and meta-analysis

The superior gluteal nerve (SGN) is a mixed nerve of the sacral plexus that arises from the posterior divisions of the L4, L5, and S1 nerve roots. Its motor branch plays a crucial role in innervation of hip muscles, which allows for physiological gait or walk-pattern. As for its sensory branch, it provides innervation for the hip joint capsule, especially its superior part. The understanding of this nerve is crucial as it may be injured during many operations involving mostly pelvic surgery, both arthroscopic and open procedures. The risk of injury is especially high during total hip arthroplasty (THA). These lesions often result in the presentation of major walk-pattern abnormalities. The most classical and commonly known would be the Trendelenburg sign, which presents with pelvic instability characterized by having the patient standing on one leg whereby the pelvis on the contralateral side will be dropping, resulting in a positive sign. The aim of this meta-analysis was to obtain all relevant data on SGN and its variations, in order to emphasize its anatomical, physiological, as well as clinical implications. A large-scale search was conducted in all major databases (PubMed, Embase, Science Direct, Google Scholar, and Web of Science) in order to determine and pool all available and relevant SGN data. No restrictions were applied to date or language. The data collection was categorized by prevalence, branching, patterns, course, origin, and distance from anatomical landmarks. A total of 41 studies (n = 869 hemipelves) were included in our analysis. The most common branching pattern of SGN was a spray pattern, 70.4% (95% CI: 54.4-96.8; p < 0.001) of the general population. We found that the closest branch to the greater trochanter of the femur and concurrently the most at risk during surgery was a muscular branch to gluteus minimus muscle. As the trend of pelvic surgeries, especially THA continues to rise, SGN lesions are now more than ever at risk. Yet to the authors' knowledge, this does not seem to be reflected in the current literature thereby making this the first meta-analysis concerning this important anatomical structure. The authors believe it is paramount for surgeons, especially in the orthopedic specialty, to thoroughly understand the SGN with its anatomical variability and clinical tie-ins.

Diagnosis and Treatment Influence Hospital Costs of Revision Total Hip Arthroplasty: A Systematic Review and Meta-Analysis

BACKGROUND

This systematic review and meta-analysis aimed to synthesize the hospital costs of revision total hip arthroplasty (rTHA) by periprosthetic joint infection, periprosthetic fracture (PPF), aseptic loosening, and recurrent dislocation diagnoses. In addition, as several surgical options are available within some diagnoses, this study aimed to synthesize the evidence on hospital costs for septic rTHA between debridement, antibiotics, and implant retention and one-stage and two-stage rTHA, and for PPF, the cost between rTHA and open reduction and internal fixation treatment.

METHODS

A systematic search of PubMed, Embase, and Scopus identified all studies reporting the hospital costs of rTHA. Screening, data extraction, and risk of bias assessment were conducted. Hospital costs of each study cohort by main diagnosis and treatment were adjusted to 2024 United States Dollar and pooled using a random-effects model.

RESULTS

Of 866 publications identified, 24 studies were included in the meta-analysis. Mean pooled costs of rTHA for dislocation, aseptic loosening, PPF, and septic rTHA were $25,256, $34,533, $35,904, and $55,707, respectively. The mean cost of septic rTHA (16 study cohorts) at $57,264 was 87% higher than aseptic rTHA (22 cohorts) at $30,224. A two-stage septic rTHA ($70,311) cost 77% more than one-stage septic rTHAs ($39,676). The cost of rTHA for PPF ($35,904) was 26% more than open reduction and internal fixation for PPF ($28,410).

CONCLUSIONS

The cost of rTHA is progressively higher by diagnosis in the order of dislocation, aseptic loosening, PPF, and infection. Future studies should separately report rTHA costs by diagnosis and treatment type and longitudinally examine the hospital costs of this patient cohort, particularly for septic cases, beyond initial treatment to better understand the burden of rTHA.

Why Do Total Joint Arthroplasties Get Canceled on the Day of Surgery?

BACKGROUND

Same-day cancellations of elective surgeries present challenges to patients, providers, and health-care institutions. This study aimed to investigate the frequency and predictors of same-day cancellations for elective total joint arthroplasty (TJA).

METHODS

A retrospective review was conducted on 13,744 scheduled primary, elective TJAs at an urban academic center from September 2017 to August 2023. Cases that experienced same-day cancellations were grouped based on the reasoning for cancellation into one of two categories - operative concern (e.g., acute health issues and medication noncompliance) or a nonoperative concern (e.g., financial clearance and transportation issues). Patient demographics were compared between the cancellation and surgery cohorts and between the categorical reasons for cancellation.

RESULTS

Out of the 38,849 scheduled TJAs, 362 cases (0.9%) were canceled on the day of surgery. Higher patient body mass index was the singular patient factor predictive of same-day cancellation across all TJAs. Non-White race, men, and higher Charlson comorbidity index were additional significant predictors for total hip arthroplasty, but not TKA cancellation. Operative concerns accounted for 74.9% of the cancellations, and nonoperative concerns accounted for 25.1%. Increased patient body mass index was predictive of TJAs canceled due to operative concerns, whereas younger patient age was predictive of TJAs canceled due to nonoperative concerns. Of all same-day cancellations, 81.8% were ultimately rescheduled, and rescheduled cases occurred at a median of 25 days (range, one to 425) after cancellation. There were no significant differences in rescheduling rates and time to reschedule cases between the reasons for cancellation.

CONCLUSIONS

Approximately, 1% of patients experienced a same-day cancellation of their elective TJA, most of which occurred due to operative concerns. These findings may guide the development of preoperative optimization strategies aimed at reducing the occurrence of same-day cancellations for high-risk patients, thereby maximizing the utilization of operative resources and enhancing care for TJA patients.

ZnO Nanoparticle-Infused Vaterite Coatings: A Novel Approach for Antimicrobial Titanium Implant Surfaces

Loss of implant function is a common complication in orthopaedic and dental surgery. Among the primary causes of implant failure are peri-implant infections which often result in implant removal. This study demonstrates the development of a new antimicrobial titanium coating with ZnO nanoparticles of various sizes and morphologies immobilised in poly(allylamine hydrochloride) and alginate multilayers, combined with epitaxially grown vaterite crystals. The coated samples were characterised with various methods (FTIR, XRD, SEM) and surface properties were evaluated via water contact angle and surface charge measurements. Zinc ion release was quantified using ICP-MS. The antimicrobial efficacy of the coatings was tested against Staphylococcus aureus, Staphylococcus epidermidis, and Candida albicans while the biocompatibility was tested with preosteoblast cells (MC3T3-E1). Results demonstrated the successful preparation of a calcium carbonate/ZnO composite coating with epitaxially grown vaterite on titanium surfaces. The Zn ions released from ZnO nanoparticles dramatically influenced the morphology of vaterite where a new flower-like morphology was observed. The coated titanium surfaces exhibited robust antimicrobial activity, achieving over 90% microbial viability reduction for Staphylococcus aureus, Staphylococcus epidermidis, and Candida albicans. Importantly, the released Zn2+ concentrations remained below the cytotoxicity limit for MC3T3-E1 cells, showing potential for safe and effective implant applications.

Total femur replacement in revision arthroplasty for non-oncologic patients: a systematic review

PURPOSE

Revision total joint arthroplasty cases including those complex enough to require limb-salvage procedures are expected to significantly increase. Total femoral replacements represent a limb-preserving procedure with potential utility for these complicated cases. This review seeks to summarize the outcomes of total femoral replacements when used in the revision arthroplasty setting.

METHODS

A systematic review was performed by searching Embase, Ovid MEDLINE, PubMed, Wiley Cochrane Library: Central Register of Controlled Trials, and Thompson Reuters Web of Science: Citation Index on February 8, 2024 for studies describing any outcomes and complications of total femur replacements performed for revision arthroplasty. Functional outcomes and postoperative complications were subsequently summarized. This study was registered with PROSPERO (CRD42024509031). Risk of bias assessment was performed using the Methodological Index for Nonrandomized Studies.

RESULTS

Eleven of 4817 initially screened studies were included. Indications for total femur replacement largely consisted of periprosthetic infection, periprosthetic fracture, hardware loosening, or a combination thereof. Articles described variable benefit in function, pain, and ambulatory ability. Patients had improved hip and knee function, reduced pain levels, and preserved independent ambulatory ability, though patients largely still required assistive devices. Benefits were limited by the high risk of postoperative complications, especially infection and dislocation.

CONCLUSION

Total femur replacement is an option for limb-salvage surgery in complex revision arthroplasty cases but has high complication rates, particularly infection and dislocation. Advancements aimed at minimizing these complication rates including silver- and iodine-coated implants will be critical in establishing the viability of total femur replacements in this setting.

Incidence, predictors, and outcomes of sepsis in revision total hip arthroplasty (rTHA)

INTRODUCTION

Revision total hip arthroplasty (rTHA) is increasingly common, with sepsis being a serious but rare complication. Sepsis rates in rTHA vary widely, and understanding risk factors is crucial for improving outcomes. This study aims to evaluate the incidence of sepsis following rTHA and identify preoperative and intraoperative predictors.

METHODS

A retrospective observational study using the ACS NSQIP (American College of Surgeons National Surgical Quality Improvement Program) database analyzed 12,966 rTHA patients (2016-2021). Predictors of sepsis were identified through univariate and multivariate analysis, including demographic, comorbid, and surgical factors. The primary endpoint was identifying sepsis predictors; secondary endpoints included sepsis incidence across patient groups.

RESULTS

In a cohort of 12,966 patients undergoing revision total hip arthroplasty, the incidence of sepsis was 1.9% (251 patients). Preoperative factors associated with increased sepsis incidence included diabetes (2.6%), smoking (2.9%), dyspnea (3.7%), severe chronic obstructive pulmonary disease (COPD) (3.5%), dialysis (5.3%), open wounds (9.5%), steroid use (3.1%), partial/total dependence (3.5%), and American society of anesthesiologists (ASA) III-IV status (2.7%). Multivariate analysis identified several predictors of sepsis, including age (OR + 0.02 per year), total operation time (OR -0.004 per minute), open wounds (OR 3.6), severe COPD (OR 1.9), transfusion within 72 h (OR 3.3), dyspnea (OR 8.1), and emergent cases (OR 3.4). The sepsis group had higher adverse outcomes, including a 30-day mortality rate of 0.8% (vs. 0.22% in non-septic patients), higher rates of deep vein thrombosis (2.8% vs. 0.7%), pulmonary embolism (1.6% vs. 0.5%), stroke (0.8% vs. 0.2%), and acute renal failure (1.2% vs. 0.1%), all with significant p-values and higher odds ratios.

CONCLUSION

Sepsis after rTHA is a significant complication. Predictors include age, open wounds, COPD, dyspnea, and transfusions. Identifying at-risk patients can improve prevention and management strategies to enhance patient outcomes.

Projections of utilization of primary and revision shoulder arthroplasty in the United States in the next 40 years

Background

In the past 20 years, the incidence of total shoulder arthroplasty (TSA) has increased greatly, and it is expected to continue growing. Current literature lacks future projections for the utilization of TSA. These projections can help predict demand quantities and anticipate the future burden on the healthcare system. The aim of this study is to determine the predictions of utilization for TSA, primary and revision, through 2060.

Methods

This analysis used the publicly available 2000-2019 data from the Center for Medicare and Medicaid Services Medicare Part-B National Summary. Procedure volumes, including TSA and revision TSA, were determined using Current Procedural Terminology codes and were uplifted to account for the growing number of Medicare eligible patients covered under Medicare Advantage. Log-linear, Poisson, negative binomial regression, and autoregressive integrated moving average models were applied to the procedural volumes to generate projections from 2020-2060. The Poisson model was chosen to display the data based on error analysis and prior literature.

Results

The projected annual growth from 2020 to 2060 rates for primary and revision TSA are 11.65% growth (95% confidence interval 11.60%-11.69%) and 13.89% growth (95% confidence interval 13.35%-14.42%), respectively. By 2060, the demand for primary TSA and revision TSA is projected to be 10,029,260 and 1,690,634, respectively.

Conclusion

The results of this study concluded that both primary and revision TSA procedures are projected to exponentially increase from 2020 to 2060. Additionally, revision procedures are projected to increase at greater rates than their respective primary counterparts.

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.

[Hip surgery: 3D printed implants in revision arthroplasty]

The adoption of 3D printing technology in hip surgery marks a substantial leap forward in orthopedic surgery. This innovative approach allows for the creation of patient-specific implants that significantly enhance fit and functionality. In our study, we demonstrate the different uses of 3D-printing techniques and their preoperative, intraoperative, and postoperative use in hip surgery for the treatment of complex acetabular defects. Moreover, the clinical outcomes of 3D-printed implants have been discussed. By overcoming many limitations of traditional manufacturing methods, 3D printing facilitates the production of complex geometries and highly porous structures that improve implant fixation and promote better bone ingrowth. We believe that in the upcoming years, with the help of new technical improvements, the use of 3D-printed implants will increase.

Imaging evaluation of periprosthetic loosening: A primer for the general radiologist

In response to an ageing global population, the primary hip and knee arthroplasty rate continues to increase. Although an effective treatment, up to 25% patients may require revision arthroplasty during their lifetime, commonly due to periprosthetic loosening. Revision procedures are associated with significantly increased healthcare costs; therefore, timely and accurate diagnostics are critical for clinicians and patients. Loosening, which may be septic or aseptic, remains a challenge and requires thorough clinical examination and multimodal imaging evaluation. Plain radiographs remain an essential diagnostic tool but advanced imaging modalities such as computed tomography, magnetic resonance imaging and nuclear medicine are playing an increasingly important role. This comprehensive review, through outlining the available radiological modalities, their respective strengths and weaknesses and the pertinent imaging findings, may help radiologists and orthopaedic surgeons make more informed decisions in the management of periprosthetic loosening.

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 to 2013 and 2014 to 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.

CONCLUSIONS

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.

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.

Total Hip Arthroplasty Patients Who Have Ostomies Have an Increased Risk of Revisions for Periprosthetic Joint Infection, but Total Knee Arthroplasty Patients Do Not

BACKGROUND

Patient comorbidities can lead to worse outcomes and increase the risk of revisions after total hip arthroplasty (THA) and total knee arthroplasty (TKA). Sparse research is available on the effects of ostomies on postoperative outcomes. Our study aimed to assess whether patients who have ostomies, who underwent TKA or THA, have worse outcomes and increased rates of all-cause and periprosthetic joint infection (PJI)-related revisions.

METHODS

We performed a retrospective cohort study comparing the outcomes of THA and TKA patients who have and do not have a history of ostomy using the Statewide Planning and Research Cooperative System. Patient demographics, ostomy diagnosis, 3-month emergency department visits and readmissions, and revisions were collected. A total of 126,414 THA and 216,037 TKA cases were included. Log-rank testing and a Cox proportional hazards model were used to account for covariates.

RESULTS

In total, 463 THA patients (0.4%) had ostomies. They had a longer length of stay (4.0 versus 3.1 days, P < 0.001) and were less likely to be discharged home (55.3 versus 62.2%, P = 0.01). They had higher rates of PJI-related revisions (1.9 versus 0.9%, P = 0.02) and had increased odds of PJI-related revision (OR [odds ratio] = 2.2, P = 0.02). Of TKA patients, 619 patients (0.3%) had an ostomy. They had a longer length of stay (3.6 versus 3.3 days, P = 0.02) and was less likely to be discharged home (49.4 versus 52.4%, P = 0.16). However, there was no difference in the rate (1.8 versus 1.4%, P = 0.49) or odds (OR = 1.2, P = 0.53) of PJI-related revision.

CONCLUSIONS

THA, but not TKA, patients who have ostomies have an increased risk of PJI-related revisions. The proximity of the surgical incision to the ostomy site may play a role in the risk of PJI in THA patients.

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.

Floating-embedded stems reduce tibial stress shielding in total knee revision arthroplasty

BACKGROUND

Total knee arthroplasty (TKA) is one of the most common orthopaedic procedures and the number of patients which undergo TKA will continue to rise in the coming years. Consecutively, the number of necessary revision surgeries will increase. One of the main reasons for revision surgery is aseptic loosening because of a so-called stress-shielding effect. Typically, revision of a primary TKA is done from a bicondylar surface replacement to a stem-anchored prosthesis, which, due to higher stress-shielding, have a shorter survival time than non-stem-anchored systems. Similar to endoprosthetic treatment in pediatric tumor orthopedics, non-ingrown cementless stems can be used. The study aim was to investigate whether this concept can also be applied to reduce stress-shielding in the tibial metaphysis after revision TKA in adults.

METHODS

Six tibial biomechanical bone with stemmed tibial TKA components were implanted using surface cementing and a floating-embedded stem or classic full cementing. After implantation, axial force was applied in such a way that the same load was generated as during walking. Two high-resolution cameras and illumination spots were used to record changes on the bone surface circumferentially in three regions of interest and from three different views.

RESULTS

With regard to the fixation method, a significant difference could be demonstrated in the metaphyseal and in the middle region around the stem (p < 0.001). At the tip of the stems, the reduction of strain energy density showed a stress shielding reduction for the floating-stemmed models in two of three views (ventromedial p = 0.002, lateral p = 0.398, and dorsal: p = 0.027).

CONCLUSIONS

In revision surgery after TKA, the use of floating-embedded, uncemented stems without bony ingrowth shows significant reduction of metaphyseal stress-shielding within the proximal tibia. This technique could be a viable alternative to prevent early aseptic loosening and should be examined in future in-vivo studies.

Robotic-assistance is associated with better joint outcomes compared to conventional techniques in surgically routine total hip arthroplasty: a propensity-matched large database study of 3948 patients

INTRODUCTION

The outcomes of total hip arthroplasty (THA) are highly dependent upon the restoration of native hip biomechanics and optimal component positioning. Robotic technologies for THA have rapidly improved the accuracy of component positioning and maintaining the planned center of rotation. While robotic-assisted THA (RA-THA) has primarily been employed in surgically intricate cases, its potential benefits in scenarios of diminished surgical complexity remain less explored. Therefore, the purpose of this study was to assess the odds of developing systemic and joint complications following RA-THA in cases of reduced surgical complexity.

METHODS

A retrospective cohort study was conducted using the TriNetX national database to identify patients who underwent primary THA (Current Procedural Terminology code 27,130) and more specifically RA-THA identified by ICD-10-PCS code 8E0Y0CZ and Healthcare Common Procedure Coding System code S2900 from 2013 to 2022. One-to-one propensity score matching was conducted to generate 2 cohorts: (1) RA-THA and (2) conventional THA (C-THA). Systemic and joint complications were assessed at the 30-day, 90-day, 1-year, and 5-year postoperative periods.

RESULTS

Patients undergoing RA-THA had a lower risk of needing a revision THA at the 90-day, 1-year, and 5-year time points. RA-THA was associated with a lower risk of prosthetic dislocation at 90 days and 1 year and prosthetic pain at 1 year and 5 years. Dislocation of the hip or fracture of the femur was significantly lower in the RA-THA cohort at all four-time points. Patients undergoing RA-THA had a lower risk of developing deep vein thrombosis at 5 years.

CONCLUSION

These findings suggest that RA-THA has comparable systemic and less joint complication risks at 30-day to 5-year timepoints between RA-THA and C-THA. Future studies with large sample sizes and long-term follow-up are needed to understand the patient-reported outcomes and functional outcomes of RA-THA for cases with reduced surgical complexity.

The effect of general versus spinal anesthesia on perioperative innate immune function in patients undergoing total hip arthroplasty

BACKGROUND

Increasing evidence shows that postoperative innate immune dysregulation is associated with delayed recovery and infectious complications. The aim of this study was to compare the effects of general versus spinal anesthesia on innate immune function during and after total hip arthroplasty (THA).

METHODS

This comparative matched cohort study used data from two single-center randomized-controlled trials. Patients from the control group of the HIPPO study received general anesthesia and were matched to control patients from the MAGIC study who received spinal anesthesia in a 2:1 ratio (general(n = 18); spinal(n = 9)). Immune function was assessed by determination of ex vivo cytokine production capacity upon whole blood stimulation with E. coli lipopolysaccharides (LPS) and measurement of plasma cytokines and danger-associated molecular patterns (DAMPs).

RESULTS

In the general anesthesia group, ex vivo cytokine production capacity of IL-1β was significantly lower shortly after induction (p = 0.02) and both IL-1β and IL-6 were significantly lower at the end of surgery compared to the spinal anesthesia group (p = 0.002 and p = 0.02, respectively). On postoperative day 1 (POD1), no differences were observed. Plasma cytokine concentrations did not differ between the spinal and general anesthesia group at most timepoints, except for IL-10 at the end of surgery (p = 0.04) and TNF on POD1 (p = 0.04), which were higher in the general anesthesia group. Plasma concentrations of DAMPs did not differ between the groups.

CONCLUSIONS

General anesthesia has a transient impact on innate immune function in patients undergoing THA, but the clinical significance of anesthesia-induced innate immune dysregulation might be limited as no differences were observed on POD1.

TRIAL REGISTRATION

The HIPPO study (NCT05562999, date of registration 2022-10-03) and MAGIC study (NCT05723406, date of registration 2023-02-10) are registered at ClinicalTrials.gov.

Trends in Payments for Ambulatory Surgery Center Facility Fees and Surgeon Professional Fees for Hip and Knee Arthroplasty

BACKGROUND

Ambulatory surgery centers (ASCs) have been shown to deliver high-quality care to patients at major cost savings to the health care system. The objective of this investigation was to examine trends in the Medicare facility and surgeon professional fee payments for hip and knee arthroplasty.

METHODS

Publicly available Medicare data were analyzed to determine professional and facility fee payments for unicompartmental knee arthroplasty (UKA), total knee arthroplasty (TKA), and total hip arthroplasty (THA) to ASCs and hospitals between 2018 and 2024. The Physician Fee Schedule Lookup Tool and the Medicare ASC payment rate files were used to determine professional fee payments and facility fee reimbursements, respectively. Descriptive statistics were used to calculate means and percent change over time. The compound annual growth rates were calculated.

RESULTS

After adjusting for inflation, Medicare professional fees declined significantly over the study period for UKA ($1,487.44 versus $1,147.50; P = 0.003), TKA ($1,738.99 versus $1,278.59; P = 0.003), and THA ($1,740.73 versus $1,280.52; P = 0.003). Medicare ASC facility fees also declined, albeit to a lesser degree for UKA ($9,007.62 versus $8,905.71; P = 0.764), TKA ($10,204.46 versus $9,048.76; P = 0.027), and THA ($9,982.66 versus $9,238.05; P = 0.308). Facility fee reimbursement decreased year over year, with annual percent change ranging from -0.19% for UKA to -2.49% for THA. Trends in Medicare hospital facility fees directly mirrored ASC facility fees over the study period. Professional fees also declined year over year, with annual percent changes ranging from -3.81% for UKA to -4.41% for TKA and THA.

CONCLUSIONS

The ASC facility fees and professional fees both declined over the study period, with declines in professional fees far outpacing those of facility fees. Urgent reform of the Medicare payment structure is needed to ensure orthopaedic practice solvency and access to high-quality care for beneficiaries.

Elbow arthroplasty utilization in 2060: projections of primary and revision elbow arthroplasty in the United States in the next 40 years

BACKGROUND

In the past decade, the prevalence of end-stage inflammatory elbow arthritis has declined with consequential changes in indications and utilization of total elbow arthroplasty (TEA). Current literature lacks future projections for the utilization of TEA. The aim of this study is to review the trends in the utilization of TEA in the last 2 decades and determine the projections of utilization for TEA (primary and revision) through 2060.

METHODS

This analysis used the publicly available 2000-2019 data from the CMS Medicare Part-B National Summary. Procedure volumes including TEA, and revision TEA, were determined using Current Procedural Terminology codes and were uplifted to account for the growing number of Medicare eligible patients covered under Medicare Advantage. Using these volumes, log-linear, Poisson, negative binomial regression, and autoregressive integrated moving average models were applied to generate projections from 2020 to 2060. The Poisson model was chosen to display the data based on error analysis and prior literature.

RESULTS

The projected annual growth rates from 2020 to 2060 for primary and revision TEAs are 1.03% (95% confidence interval: 0.82%-1.25%) and 5.17% (95% confidence interval: 3.02%-6.97%), respectively. By 2060, the demand for primary TEA and revision TEA is projected to be 2084 procedures (95% forecast interval: 1995-2174) and 3161 procedures (95% forecast interval: 3052-3272), respectively. The procedure volume for revision TEA is estimated to outnumber primary TEA by year 2050.

CONCLUSION

The overall procedural volume of primary TEA and revision TEA continues to be low. Although it is estimated that the incidence of primary and revision TEAs will continue to increase in the next 40 years, the utilization trends only show a mild increase, which is 5 times higher for revision TEA than primary TEA.

Evaluation of conventional and CT-based radiostereometric analysis for inducible displacement measurements after total hip arthroplasty

Though radiostereometric analysis (RSA) is the gold standard for migration tracking, computed tomography-based RSA (CT-RSA) does not require marker beads and is available for clinical adoption. This study investigated CT-RSA in comparison to RSA for assessing hip implant stability with inducible displacement (ID) examinations. Patients (n = 48) from a previous study returned to be re-examined for femoral stem stability with CT-RSA and RSA imaging. Implant migration since patients last follow-up was calculated as a measure of stability. ID was assessed between alternated leg rotation scans for CT-RSA and between supine and weight-bearing scans for RSA. Measurements from ID and double examinations were compared between CT-RSA and RSA. All stems were well-fixed with migration <0.2 mm/year. ID measurements were lower with CT-RSA than RSA for distal translation (mean difference = 0.122 mm, p < 0.0001), total translation (mean difference = 0.158 mm, p < 0.0001), and total rotation (mean difference = 0.449°, p < 0.0001). The ID and double exam were significantly different for total translation and total rotation for CT-RSA, and significantly different for medial, distal, and total translation, and total rotation for RSA. Precision ranged from 0.049 to 0.130 mm in translation and 0.061° to 0.220° in rotation for CT-RSA, and from 0.108 to 0.269 mm in translation and 0.151° to 0.670° in rotation for RSA. ID measurements from both CT-RSA and RSA were minimal, consistent for a cohort with well-fixed stems. CT-RSA demonstrated superior precision in all axes compared to RSA. Clinical Significance: Future work should explore the use of CT-RSA in patients with suspected loosening as a potential diagnostic tool.

Predictive Factors of Inpatient Rehabilitation Stay and Post-Discharge Burden of Care After Joint Replacement for Hip and Knee Osteoarthritis: A Retrospective Study on 1678 Patients

The global demand for end-stage hip and knee osteoarthritis surgical treatment is rising, as is the need of optimal postoperative rehabilitation. Patient stratification is key to provide rehabilitation professionals and policy makers with real-life data in support of early discharge planning and continuous care provision. The aim of this retrospective, observational study was to investigate which factors can predict the burden of care at discharge (BCD) and the inpatient rehabilitation length of stay (LOS) based on a set of demographic, societal, clinical and organizational data collected from a high-volume orthopedic hospital. We included 45.306 variables from 1678 patients. All variables were initially tested individually using a linear regression model for inpatient rehabilitation LOS and a logistic regression model for BCD. Variables that resulted significant (p < 0.05) were subsequently considered in a single, comprehensive linear regression model, or a single, logistic regression model, respectively. Age, living with a family, occupational status, baseline Barthel Index and duration of surgery were predictors of inpatient rehabilitation LOS and BCD. Sex, primary or secondary osteoarthritis, American Society of Anesthesiologists score, body mass index, transfusion, biological risk, type of anesthesia, day of surgery, numeric pain rating scale and baseline cognitive function at baseline were not. Including specific patient comorbidities, surgical access technique and chronic use of pharmacological therapy can improve the predictive power of the model.

Rising Costs and Diminishing Surgeon Reimbursement From Primary to Revision Total Hip and Knee Arthroplasty: An Analysis of Medicare Advantage and Commercial Insurance

BACKGROUND

Revision total joint arthroplasty (rTJA) is a resource-intensive procedure addressing failed primary total joint hip (total hip arthroplasty [THA]) and knee arthroplasty (total knee arthroplasty [TKA]). Despite predictions of increased demand, reimbursement for rTJA has not kept pace with increasing costs and may be insufficient compared with primary procedures. The study aimed to highlight the diminishing surgeon reimbursement between primary and revision THA (rTHA) and TKA.

METHODS

This study is a retrospective analysis of billing data for primary and rTHA and TKA procedures from a single institution between 2019 and 2022. Insurance claims and charges data were provided by a local affiliate of a major national carrier which includes Medicare Advantage (MA) and commercial patients. Using insurance data, the study evaluates the total surgery costs for primary and rTHA and TKA and the individual charges that make up the total surgery cost.

RESULTS

Nine hundred five patients insured by the same carrier, who underwent a primary or rTJA, were identified. Irrespective of MA or commercial insurance, the average surgery cost for a primary THA was $26,043, compared with $53,456 for rTHA. Surgeon reimbursement for primary THA was 20% ($5,323) of the total surgery cost. Despite the doubled surgery cost for rTHA, surgeon reimbursement was 10% ($5,257) of the total surgery cost. Primary TKA surgery costs were $24,489, while revision costs were $43,074. Surgeon reimbursement for primary TKA was 20% ($4,918) of the total surgery cost, while reimbursement for revision TKA was 13% ($5,560). MA reimbursement was markedly lower than commercial reimbursement for primary and revision cases.

CONCLUSION

Despite the higher total costs for rTJA, surgeon reimbursement is disproportionately diminished. The findings highlight the lack of incentive for revision cases. Surgeon reimbursement from MA and commercially insured patients for rTJA remains inadequate. This may limit patient access-to-care, leading to suboptimal outcomes and increased healthcare utilization.

Socioeconomic area deprivation index is not associated with postoperative complications following revision total hip and knee joint arthroplasty

Introduction

Revision hip and knee total joint arthroplasty (TJA) carries a high burden of postoperative complications, including surgical site infections (SSI), venous thromboembolism (VTE), reoperation, and readmission, which negatively affect postoperative outcomes and patient satisfaction. Socioeconomic area-level composite indices such as the area deprivation index (ADI) are increasingly important measures of social determinants of health (SDoH). This study aims to determine the potential association between ADI and SSI, VTE, reoperation, and readmission occurrence 90 days following revision TJA.

Methods

1047 consecutive revision TJA patients were retrospectively reviewed. Complications, including SSI, VTE, reoperation, and readmission, were combined into one dependent variable. ADI rankings were extracted using residential zip codes and categorized into quartiles. Univariate and multivariate logistic regressions were performed to analyze the association of ADI as an independent factor for complication following revision TJA.

Results

Depression (p = 0.034) and high ASA score (p < 0.001) were associated with higher odds of a combined complication postoperatively on univariate logistic regression. ADI was not associated with the occurrence of any of the complications recorded following surgery (p = 0.092). ASA remained an independent risk factor for developing postoperative complications on multivariate analysis.

Conclusion

An ASA score of 3 or higher was significantly associated with higher odds of developing postoperative complications. Our findings suggest that ADI alone may not be a sufficient tool for predicting postoperative outcomes following revision TJA, and other area-level indices should be further investigated as potential markers of social determinants of health.

Periprocedural clinical outcomes of revision hip arthroplasty: a multi-centric comparison of current strategies based on the NSQIP

INTRODUCTION

Recent projections suggest a substantial rise in demand for revision total hip arthroplasties, emphasizing the need for optimized perioperative care. Various revision techniques, such as isolated acetabular or femoral component revisions and total replacements, have garnered attention. Further research is needed to establish the most effective strategies for improving clinical outcomes.

METHODS

This retrospective analysis utilized data from the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) Participant Use File from 2016 to 2021. The study aimed to compare clinical characteristics and 30-day outcomes among patients undergoing combined acetabular and femoral (A + F) revision,  acetabulum-only (A) revision, and femoral side-only (F) revision surgeries.

RESULTS

The analysis of 18,888 patients revealed crucial differences in preoperative and postoperative outcomes among various revision strategies. Specifically, there were notable variations in patient demographics, comorbidities, and emergency procedures. Postoperative data showed distinct rates of mortality, complications, and readmissions across the groups. Notably, femoral component revisions were associated with increased risks of mortality, transfusion, and urinary tract infections, underscoring the need for careful evaluation and consideration when opting for this revision approach.

CONCLUSION

The study's significance lies in its extensive patient cohort and multifaceted evaluation of revision strategies. Although consensus is lacking on single-component revisions, targeting the acetabulum component appears relatively safer. Continued research and individualized evaluations are crucial for refining revision strategies and optimizing outcomes in THA revisions.

Perioperative Demographic and Laboratory Characteristics of Failed Debridement, Antibiotics, and Implant Retention: Can We Determine Which Patients Will Fail?

BACKGROUND

Debridement, antibiotics, and implant retention (DAIR) are the mainstays surgical treatment for acute periprosthetic joint infection (PJI). However, reoperation following DAIR is common and the risk factors for DAIR failure remain unclear. This study aimed to assess the perioperative characteristics of patients who failed initial DAIR treatment.

METHODS

A retrospective review was conducted on 83 patients who underwent DAIR for acute PJI within 3 months following index surgery from 2011 to 2022, with a minimum one-year follow-up. Surgical outcomes were categorized using the Musculoskeletal Infection Society outcome reporting tool (Tiers 1 to 4). Patient demographics, laboratory data, and perioperative outcomes were compared between patients who had failed (Tiers 3 and 4) (n = 32) and successful (Tiers 1 and 2) (n = 51) DAIR treatment. Logistic regression was also performed.

RESULTS

After logistic regression, Charlson Comorbidity Index (odds ratio [OR]: 1.57; P = .003), preoperative C-reactive protein (OR: 1.06; P = .014), synovial white blood cell (OR: 1.14; P = .008), and polymorphonuclear cell (PMN%) counts (OR: 1.05; P = .015) were independently associated with failed DAIR. Compared with total hip arthroplasty, total knee arthroplasty patients (OR: 6.08; P = .001) were at increased risk of DAIR failure. The type of organism and time from primary surgery were not correlated with DAIR failure.

CONCLUSIONS

Patients who had failed initial DAIR tended to have significantly higher Charlson Comorbidity Index, C-reactive protein, synovial white blood cell, and PMN%. The total knee arthroplasty DAIRs were more likely to fail than the total hip arthroplasty DAIRs. These characteristics should be considered when planning acute PJI management, as certain patients may be at higher risk for DAIR failure and may benefit from other surgical treatments.

LEVEL OF EVIDENCE

III.

The role of MRI in the diagnosis of aseptic loosening following total hip arthroplasty

INTRODUCTION

The role of advanced imaging in diagnosing aseptic implant loosening following total hip arthroplasty (THA) remains unclear. This study aimed to assess the diagnostic value of magnetic resonance imaging (MRI) in detecting aseptic loosening.

METHODS

This was a retrospective review of 342 consecutive patients who underwent revision THA between July 2011 and April 2023 and had a pelvis MRI as part of the preoperative diagnostic evaluation. Among them, 62 patients had an intraoperative diagnosis of aseptic loosening of either the femoral or acetabular component. Patients were stratified based on the concordance between their MRI and radiographs findings.

RESULTS

Preoperative MRI showed signs of aseptic loosening in 25/62 patients (sensitivity = 40.3%). Similarly, preoperative radiographs demonstrated signs of aseptic loosening in 27 patients (43.5%). Twelve patients (19.4%) had both MRI and radiographs predictive of aseptic loosening, 22 patients (35.5%) did not show signs of aseptic loosening in either MRI or radiographs, and for 28 patients (45.2%), the results were discordant. Among the patients with a negative radiograph for aseptic loosening (n = 35), 13 patients (37.1%) showed signs of aseptic loosening on MRI.

CONCLUSION

Aseptic loosening remains an elusive diagnosis, and the findings of this study suggest that the utility of MRI and radiographs as part of the diagnostic process is limited. However, in cases of presumed aseptic loosening with inconclusive radiographs findings, MRI may play a role in improving the diagnostic process.

LEVEL OF EVIDENCE

III.

Contemporary Outcomes of Proximal Femoral Replacement as a Salvage Treatment in Nononcologic Severe Bone Loss

BACKGROUND

Severe proximal femoral bone loss remains a challenging problem in revision total hip arthroplasty (rTHA). Proximal femoral replacements (PFRs) are salvage options for severe bone loss in complex rTHA. The purpose of this study was to describe the survivorship and clinical outcomes of PFR for nononcologic indications.

METHODS

We performed a retrospective review of 49 patients who underwent 50 PFRs from January 2014 to May 2021 at a single institution. Indications for PFR included periprosthetic femur fracture (n = 20), reimplantation after periprosthetic joint infection (n = 18), aseptic loosening with severe proximal femoral bone loss (n = 10), heterotopic ossification (n = 1), and instability (n = 1). The mean age was 70 years. The mean body mass index was 28 and 25 (50%) patients were women. The mean follow-up was three years. Kaplan-Meier analysis was used to assess survivorship free from reoperation, rerevision, and dislocation.

RESULTS

The 2-year survivorship free from all-cause reoperation was 78%, and the 2-year survivorship free from rerevision was 87%. Overall, there were 11 (22%) reoperations, with indications including periprosthetic joint infection (n = 6), aseptic loosening (n = 2), hematoma evacuation (n = 1), instability (n = 1), and delayed wound healing (n = 1). There were eight (16%) patients who dislocated after PFR. The mean Hip Injury and Osteoarthritis Outcome Score for Joint Replacement increased from 48 preoperatively to 77 at two years postoperatively (P < 0.001).

CONCLUSIONS

In this series of PFRs performed in complex rTHA, there was low 2-year survivorship free from all-cause reoperation (78%) and rerevision (87%). Furthermore, the dislocation rate was high at 16%. However, only one patient (2%) was revised for femoral component aseptic loosening. This study highlights the complexity of these patients and the utilization of PFR as a salvage option.

Leveraging transfer learning for predicting total knee arthroplasty failure from post-operative radiographs

Purpose

The incidence of both primary and revision total knee arthroplasty (TKA) is expected to rise, making early recognition of TKA failure crucial to prevent extensive revision surgeries. This study aims to develop a deep learning (DL) model to predict TKA failure using radiographic images.

Methods

Two patient cohorts who underwent primary TKA were retrospectively collected: one was used for the model development and the other for the external validation. Each cohort encompassed failed and non-failed subjects, according to the need for TKA revision surgery. Moreover, for each patient, one anteroposterior and one lateral radiographic view obtained during routine TKA follow-up, were considered. A transfer learning fine-tuning approach was employed. After pre-processing, the images were analyzed using a convolutional neuronal network (CNN) that was originally developed for predicting hip prosthesis failure and was based on the Densenet169 pre-trained on Imagenet. The model was tested on 20% of the images of the first cohort and externally validated on the images of the second cohort. Metrics, such as accuracy, sensitivity, specificity and area under the receiving operating characteristic curve (AUC), were calculated for the final assessment.

Results

The trained model correctly classified 108 out of 127 images in the test set, providing a classification accuracy of 0.85, sensitivity of 0.80, specificity of 0.89 and AUC of 0.86. Moreover, the model correctly classified 1547 out of 1937 in the external validation set, providing a balanced accuracy of 0.79, sensitivity of 0.80, specificity of 0.78 and AUC of 0.86.

Conclusions

The present DL model predicts TKA failure with moderate accuracy, regardless of the cause of revision surgery. Additionally, the effectiveness of the transfer learning fine-tuning approach, leveraging a previously developed DL model for hip prosthesis failure, has been successfully demonstrated.

Level of Evidence

Level III, diagnostic study.

High Rate of Unplanned Reoperation for Interprosthetic Femur Fractures After Total Hip and Knee Arthroplasty

BACKGROUND

Interprosthetic femur fractures (IPFFs) are a rare, but devastating complication following total joint arthroplasty. There is limited evidence to help guide their management. The purpose of this study was to describe the features, treatment, and outcomes of surgically managed IPFFs.

METHODS

We retrospectively identified 75 patients who had 76 IPFFs. The mean age at the time of IPFF was 75 years (range, 29 to 94), and 78% were women. The mean body mass index was 30 (range, 19 to 51), and the mean follow-up was 3 years (range, 0 to 14). There were 16 Vancouver B1 fractures, 28 Vancouver B2 fractures, 2 Vancouver B3 fractures, and 30 Vancouver C fractures. All B1 fractures underwent open reduction internal fixation (ORIF). All Vancouver B2 and B3 fractures underwent revision arthroplasty, including 1 proximal femur replacement and 1 total femur replacement. Vancouver C fractures were treated with ORIF (n = 20), distal femoral replacement (n = 9), and in 1 case, total femur replacement (n = 1). Kaplan-Meier survivorship was used to calculate 2-year survival free from all-cause reoperation and periprosthetic joint infection (PJI).

RESULTS

The 2-year survivorship-free rate from reoperation was 71%. There were 18 reoperations following initial surgical management of the IPFF, including 9 for infection, 3 for refracture, 3 for nonunion, 2 for hardware failure, and 1 for instability. An initial IPFF involving a stemmed femoral total knee arthroplasty component was associated with increased risk for reoperation (P = .007) and PJI (P = .044). There was no difference in survivorship free of reoperation between IPFFs managed with ORIF or revision arthroplasty (P = .72).

CONCLUSIONS

An IPFF is a devastating complication following total joint arthroplasty with high reoperation rates, most commonly secondary to PJI. Those IPFFs that occurred between 2 stemmed components were at the highest risk for reoperation.

Forecasting the value of innovation in total knee arthroplasty care: A headroom approach

Purpose

Total knee arthroplasty (TKA) is the standard treatment of end-stage osteoarthritis. TKA is often used and, therefore, poses a healthcare and societal burden, which is likely to increase further. Headroom analyses evaluate a technology under development by making assumptions about its effectiveness. This article applies a headroom approach to forecast the potential value of innovations that improve TKA-related care in the Netherlands in terms of cost-effectiveness and surgeries avoided.

Methods

A state-transition model estimating lifetime direct health effects, healthcare- and societal costs and percentage of avoide d surgeries was developed. The model compared care as usual to five hypothetical interventions to calculate the headroom associated with (1) preventing the need for TKAs, (2) preventing the need for all TKA revisions, (3) postponing TKAs without quality-of-life loss, (4) preventing periprosthetic joint infections (PJIs) and (5) improving patient satisfaction.

Results

Preventing the need for all TKAs amounted to €43,076 of headroom. Preventing the need for TKA revisions amounted to €2276 (5.8% of surgeries avoided), postponing TKAs by 5 years amounted to €7634 (32.4% of surgeries avoided), preventing PJIs amounted to €1187 (1.4% of surgeries avoided) and improving patient satisfaction amounted to €16,622 (0% of surgeries avoided). The headroom of each hypothetical intervention was highest in younger populations (<50 years of age).

Conclusion

There is a headroom for improving TKA-related care. Innovations to avoid or postpone TKA (i.e., joint-preserving treatments) as well as those that improve patient satisfaction can be effective in maximizing the value for money and avoiding surgeries. Due to the decreasing average patient age, innovations to reduce revision rates and PJIs will become more valuable as these are most effective in younger patients. It is currently unclear how cost-effectiveness considerations should be traded off against the prevention of surgery to reduce the increasing burden on the healthcare system.

Level of Evidence

Level III economic evaluation/decision-analytic model.

Exploring Intra-Articular Administration of Monoclonal Antibodies as a Novel Approach to Osteoarthritis Treatment: A Systematic Review

Biological drugs, including monoclonal antibodies, represent a revolutionary strategy in all fields of medicine, offering promising results even in the treatment of osteoarthritis (OA). However, their safety and efficacy have not been fully validated, highlighting the need for in-depth studies. Therefore, we provided a comprehensive systematic review of the intra-articular use of monoclonal antibodies for the treatment of OA in animal models, reflecting ongoing efforts to advance therapeutic strategies and improve patient outcomes. A systematic literature search was conducted in December 2023 following the PRISMA guidelines, using the Web of Science, Google Scholar, and PUBMED databases. Out of a total of 456, 10 articles were included in the study analyzing intra-articular antibodies and focusing on various targets, including vascular endothelial growth factor (VEGF), nerve growth factor (NGF), interleukin 4-10 (IL4-10), tumor necrosis factor α (TNF-α), a disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS5), and matrix metalloproteinase 13 (MMP-13). Most studies administered the antibodies weekly, ranging from 1 to 10 injections. Animal models varied, with mean follow-up periods of 8.9 ± 4.1 weeks. The methods of assessing outcomes, including pain and morpho-functional changes, varied. Some studies reported only morphological and immunohistochemical data, while others included a quantitative analysis of protein expression. In conclusion, monoclonal antibodies represent a promising avenue in the treatment of OA, offering targeted approaches to modulate disease pathways. Further research and clinical trials are needed to validate their safety and efficacy, with the potential to revolutionize the management of OA and reduce reliance on prosthetic interventions.

Prevalence and Risk Factors of Vitamin D Deficiency in Patients Scheduled to Undergo Revision Arthroplasty of the Hip, Knee and Shoulder-Data from a Single-Centre Analysis

Vitamin D is crucial for ideal bone health and good muscle function, both essential requirements for successful joint arthroplasty. Hence, vitamin D deficiency has recently been identified as a predictor of poorer outcomes in patients scheduled to undergo total joint arthroplasty (TJA). Moreover, there is ample evidence today that vitamin D deficiency is associated with periprosthetic joint infection. Yet, vitamin D deficiency seems to be frequent in patients who are scheduled to undergo TJA. However, the prevalence of hypovitaminosis D in patients who require revision arthroplasty (rTJA) is largely unknown. Further, risk factors of vitamin D deficiency in these patients remain to be elucidated. For this reason, the primary objective of this study was to assess the vitamin D status of patients scheduled to undergo rTJA of the hip, knee and shoulder. The secondary objective was to identify potential risk factors for hypovitaminosis D in these patients. Serum vitamin D [25(OH)D] levels of 249 patients who were scheduled for rTJA were assessed over a period of twelve months at a high-volume TJA centre. Collectively, 23% of patients reported a routine intake of vitamin D supplements (58/249). Notably, 81% of patients (155/191) who did not report a routine vitamin D intake presented with insufficient vitamin D levels (below 30 ng/mL), while only 19% of patients (36/191) had sufficient vitamin D levels. Of those who reported a routine vitamin D intake, 75% (43/58) had sufficient vitamin D levels, while 25% (15/58) showed insufficient vitamin D status. Patients who did not routinely take any vitamin D supplements had significantly lower vitamin D levels compared to patients who reported regular vitamin D intake (19.91 ng/mL vs. 40.66 ng/mL). Further, BMI and nicotine abuse were identified as potential risk factors for hypovitaminosis D in patients without vitamin D supplementation. Moreover, the season of spring seems to be a risk factor in patients with vitamin D supplementation, while age itself did not appear to be a significant risk factor for low vitamin D levels. In conclusion, we found an alarmingly high rate of vitamin D deficiency in patients scheduled to undergo rTJA. Notably, reported routine vitamin D supplementation showed significantly increased serum vitamin D levels compared to patients with no reported supplementation. Due to the high prevalence of vitamin D deficiency, we believe that vitamin D status should routinely be assessed in patients who are scheduled to undergo rTJA.

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.

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.

Multiplex cytokine analysis for the identification of novel potential synovial fluid biomarkers for periprosthetic joint infections

INTRODUCTION

Periprosthetic joint infections (PJIs) are a devastating complication of total hip (THA) and knee (TKA) arthroplasty. The use of novel techniques like multiplex cytokine analysis could contribute immensely to the identification of potential novel biomarkers.

PATIENTS AND METHODS

This is a single-centre study of patients that were treated with revision TKA, THA or hemiarthroplasty. Serum's white blood cells (WBCs), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) and synovial fluid's WBCs, percentage of polymorphonuclear neutrophils (%PMNs) and CRP were measured. Proteomic analysis targeting the secreted cytokines in synovial fluid was conducted using a 73-plex assay panel. The results were statistically compared between the septic and aseptic cases and ROC analysis to establish the area under the curve (AUC), sensitivity and specificity of each biomarker.

RESULTS

The study included 30 patients (18 revision THA cases; 3 conversion of hemiarthroplasty to THA and 9 revision TKA cases); 14 cases were considered infected, 1 likely infected and 15 not infected. The results showed statistically significant differences (p < 0.05) between infected and not infected cases in serum's ESR, CRP and synovial fluid's%PMNs, growth-regulated oncogene alpha (GROA), interleukin-8, interleukin-5, S100-A8/calprotectin and resistin (RETN) with AUCs of 0.75, 0.72, 0.95, 0.75, 0.72, 0.95, 0.83, 0.73, 0.75, 0.81 and 0.76 respectively.

CONCLUSIONS

In the present study, serum ESR and CRP as well as synovial %PMNs, GROA, IL-8, IL-5, calprotectin and RETN protein levels were identified as potential biomarkers. Further studies are needed to further investigate their diagnostic utility and optimal cut-off values.