What Are the Contemporary Etiologies for Revision Surgery and Revision After Primary, Noncemented Total Hip Arthroplasty?

How Much Protection Does a Collar Provide? Assessing Risk of Early Periprosthetic Femur Fractures Following Total Hip Arthroplasty in Elderly Patients

BACKGROUND

Periprosthetic fractures (PPFs) account for approximately 25% of early revisions following total hip arthroplasty (THA). Cemented femoral fixation is associated with a lower-risk of PPF, and collared-cementless stems may reduce the risk as well. The objective of this study was to compare early-PPF rates between cemented, collared-cementless, and non-collared cementless stems in elderly patients.

METHODS

A consecutieve-series of 11,522 primary THAs performed between 2016 and 2021 at our institution in patients >65 years of age was identified. Stem types used were categorized as cemented, collared-cementless, or non-collared cementless. Patients undergoing THA who had cemented-stems were older, more commonly women, and more likely to have a posterior-approach. To reduce confounding of patient characteristics, we matched patients in the 3 stem-categories according to age, sex, and body mass index. This generated 3-groups (cemented, collared-cementless, and non-collared cementless) consisting of 936 patients per group. The mean age of these 2,808 patients was 73 years, the mean body mass index was 27, and 67% were women. Logistic regressions were used to evaluate risk-factors for early-PPF. In the entire cohort of primary THA in elderly patients, there were 85 early PPFs (0.7%) over the study period.

RESULTS

Non-collared cementless stems were associated with an increased risk of early PPF (OR: 3.11; P = .03) compared to collared-cementless stems. There were no early PPFs in the matched cemented cohort, 6 early PPFs in the matched collared-cementless cohort, and 16 early-PPFs in the matched non-collared cementless cohort (0% versus 0.64% versus 1.71%, P < .001).

CONCLUSIONS

In this large-series of patients >65 years of age undergoing primary THA, cemented stem fixation had the lowest incidence of early PPF, but collared-cementless stems had a nearly 3-fold decrease in risk for early PPF compared to non-collared cementless stems.

Neutrophil Extracellular Trap-related Biomarkers Are Increased in the Synovial Fluid of Patients With Periprosthetic Joint Infections

BACKGROUND

The diagnosis of periprosthetic joint infection (PJI) is a major challenge in clinical practice. The role of neutrophils in fighting infection has been increasingly understood, and one mechanism of action of these cells is neutrophil extracellular traps. However, little is known about this process in PJI.

QUESTIONS/PURPOSES

(1) Are the biomarkers of neutrophil extracellular trap formation (citrullinated histone H3 [H3Cit], cell-free DNA [cf-DNA], and myeloperoxidase [MPO]) increased in the synovial fluid of patients with PJI? (2) What is the diagnostic accuracy of biomarkers of neutrophil extracellular trap formation for PJI?

METHODS

Between May 2020 and March 2021, 43 patients who underwent revision THA or TKA were enrolled in this study. Eleven patients were excluded and 32 patients were categorized into the PJI group (n = 16) or non-PJI group (n = 16) according to the 2018 Second International Consensus Meeting on Musculoskeletal Infection criteria. There were 15 men and 17 women in this study, with a median (range) age of 70 years (60 to 80 years). Twenty-seven patients had TKA and five had THA. We measured cf-DNA, MPO, and H3Cit in synovial fluid. The sensitivity, specificity, and receiver operating characteristic curve were calculated for each biomarker using the Musculoskeletal Infection Society criteria as the gold standard for diagnosis and considering a clinical surveillance of 2 years for patients in the non-PJI group.

RESULTS

Patients with PJI had higher levels of synovial fluid cf-DNA (median [range] 130 ng/µL [18 to 179] versus 2 ng/µL [0 to 6]; p < 0.001), MPO (1436 ng/µL [55 to 3996] versus 0 ng/µL [0 to 393]; p < 0.001), and H3Cit (2115 ng/µL [5 to 2885] versus 3 ng/µL [0 to 87]; p < 0.001) than those in the non-PJI group. In receiver operating characteristic curve analyses, we observed near-perfect performance for all biomarkers evaluated, with an area under the curve of 1 (95% CI 0.9 to 1), 0.98 (95% CI 0.9 to 1), and 0.94 (95% CI 0.8 to 0.99) for cf-DNA, MPO, and H3Cit, respectively. The sensitivity for detecting PJI using synovial fluid was 100% for cf-DNA, 94% for MPO, and 88% for H3Cit. The specificity was 100% for cf-DNA and MPO, and 88% for H3Cit.

CONCLUSION

Our results show that neutrophils in the periprosthetic microenvironment release neutrophil extracellular traps as part of the bactericidal arsenal to fight infection. These results allow a better understanding of the cellular and molecular processes that occur in this microenvironment, enabling the design of more assertive strategies for identifying new biomarkers and improving the available ones. Novel studies are needed to define whether and how neutrophil extracellular trap-related biomarkers can be useful for diagnosing PJI.

LEVEL OF EVIDENCE

Level II, diagnostic study.

United States Experience With a Femoral Neck Retaining Total Hip Arthroplasty Stem: A Retrospective Study With Control Comparison From the Literature

BACKGROUND

Femoral neck retaining prostheses have gained popularity in Europe, but the United States has not seen the same trends occurring. Previous reports demonstrate high survivorship for these implants, but to our knowledge, there are no reports examining US data.

METHODS

After institutional review board approval, 824 primary total hip arthroplasties utilizing a femoral neck-retaining prosthesis were examined for femoral component survivorship rates. European studies were systematically reviewed to determine survivorship rates. The data were used to formulate a Kaplan-Meier survivorship curve and compare US data to that of the European studies.

RESULTS

European studies demonstrated survivorship rates for all causes of 97.7 and 99.0% for aseptic loosening at an average of 6 years (range, 4.5 to 10). The current study demonstrated an all-cause 94% Kaplan-Meier survivorship estimate at 5 years and when aseptic loosening only was considered, survivorship increased to 99.4% at 5 years and 98.4% at 11 years.

CONCLUSION

This femoral neck-retaining prosthesis demonstrated excellent survivorship that is comparable to the rates seen in European studies as well as the rates of standard and mid-stem prostheses in the United States.

Improved radiographic outcomes and decreased complications rate on the femoral side can be achieved by a novel designed whole-process robotic assisted hip system for total hip arthroplasty: a prospective randomized controlled trial

Postoperative complications due to inaccurate prosthesis positioning are the main causes of early revision. The aim of this study was to (1) determine whether novel designed whole-process robotic assisted hip system allowed better radiographic outcomes and lower complications risk on the femoral side particularly stem subsidence compared to conventional THA, and to (2) identify the comparison of early clinical outcomes. 72 patients were initially enrolled and randomly divided into 2 groups. Finally, only 65 patients (31 RA-THAs, 34 C-THAs) were analyzed who had full 18-month follow-up data. Radiographic follow-up was performed at immediate and 6-month postoperatively, while clinical follow-up at 18-month postoperatively. Stem-related radiographic outcomes, femoral side complications and clinical scores were compared. The robotic arm allowed better radiographic outcomes of the femoral side, including a higher canal fill ratio (CFR) at B1 (P = 0.040), more neutral stem alignment (P = 0.029), lower subsidence (P = 0.023) and lower leg length discrepancy (LLD) (P = 0.010). In addition, low CFR at B1 (P = 0.001) was found the risk factor for subsidence. However, early clinical outcomes were consistent between both groups. The novel designed whole-process robotic assisted hip system covers both femoral and acetabular side operations. It allows accurate and safe manipulation of femoral side, including better stem-related radiographic outcomes and lower risk of subsidence and LLD. However, no advantage of robotic system in early clinical score was identified. Clinical trial registration number: ChiCTR2100044124.

Global mapping of institutional and hospital-based (Level II-IV) arthroplasty registries: a scoping review

PURPOSE

Four joint arthroplasty registries (JARs) levels exist based on the recorded data type. Level I JARs are national registries that record primary data. Hospital or institutional JARs (Level II-IV) document further data (patient-reported outcomes, demographic, radiographic). A worldwide list of Level II-IV JARs must be created to effectively assess and categorize these data.

METHODS

Our study is a systematic scoping review that followed the PRISMA guidelines and included 648 studies. Based on their publications, the study aimed to map the existing Level II-IV JARs worldwide. The secondary aim was to record their lifetime, publications' number and frequency and recognise differences with national JARs.

RESULTS

One hundred five Level II-IV JARs were identified. Forty-eight hospital-based, 45 institutional, and 12 regional JARs. Fifty JARs were found in America, 39 in Europe, nine in Asia, six in Oceania and one in Africa. They have published 485 cohorts, 91 case-series, 49 case-control, nine cross-sectional studies, eight registry protocols and six randomized trials. Most cohort studies were retrospective. Twenty-three per cent of papers studied patient-reported outcomes, 21.45% surgical complications, 13.73% postoperative clinical and 5.25% radiographic outcomes, and 11.88% were survival analyses. Forty-four JARs have published only one paper. Level I JARs primarily publish implant revision risk annual reports, while Level IV JARs collect comprehensive data to conduct retrospective cohort studies.

CONCLUSIONS

This is the first study mapping all Level II-IV JARs worldwide. Most JARs are found in Europe and America, reporting on retrospective cohorts, but only a few report on studies systematically.

The causal relationship between psoriasis and artificial joint re-operation after arthroplasty: A two-sample Mendelian randomization study

BACKGROUND

Psoriasis is observationally associated with a higher risk of complications of arthroplasty; however, the causal effects of psoriasis on complications of arthroplasty are yet to be established. This study was to explore the causal effect of psoriasis on artificial joint re-operation after arthroplasty through two-sample Mendelian randomization (MR).

METHODS

In the MR analysis, psoriasis was selected as the exposure in this study while single-nucleotide polymorphisms (SNPs) from a genome-wide association study (GWAS) were selected as the instrumental variables (IVs). Summary statistics data on artificial joint re-operation was extracted from publicly available GWAS data, including 218 792 European descent individuals. MR analysis was performed using the standard inverse variance weighted method (IVW). Furthermore, MR Egger, weighted median, simple mode, weighted mode, and the MR-PRESSO (Mendelian Randomization Pleiotropy Residual Sum and Outlier) test were also done to verify the results. Finally, the sensitivity analysis was executed.

RESULTS

The IVW showed that psoriasis increases the risk of artificial joint re-operation (OR = 1.12; 95% CI = (1.01, 1.25); p = 0.036). This outcome was also verified by other methods including weighted median (OR = 1.16; 95% CI = (1.03, 1.31); p = 0.015), MR Egger (OR = 1.22; 95% CI = (1.03, 1.44); p = 0.038), and weighted mode (OR = 1.16; 95% CI = (1.03, 1.30); p = 0.025). No heterogeneity and directional pleiotropy were observed upon sensitivity analysis.

CONCLUSION

The present study showed that psoriasis has a potential causal effect on artificial joint re-operation after arthroplasty. Further studies are warranted to elucidate the underlying mechanisms of causal associations between psoriasis on re-operation.

Revision Total Hip Arthroplasty with a Modular Fluted Tapered Stem for a Periprosthetic Femoral Fracture

Background

As the number of primary total hip arthroplasty procedures performed each year continues to rise, so too do the number of complications, including periprosthetic femoral fracture1-9. Vancouver B2 and B3 periprosthetic femoral fractures are difficult to treat because they require the surgeon to simultaneously manage a femoral fracture and gain new implant fixation. Fluted tapered stems have advanced the treatment of periprosthetic femoral fractures by providing immediate axial and rotational implant fixation distal to the fracture10-18. Modular fluted tapered stems provide the added practical advantage of allowing length and anteversion adjustment after implantation of the distal fixation portion of the stem.

Description

In this technique, a modified extended trochanteric osteotomy incorporating the fracture is utilized to gain access to the loose femoral implant and femoral diaphyseal canal. The femoral diaphyseal canal is then sequentially reamed in 1-mm increments. A fluted tapered stem with the appropriate length, diameter, and axial and rotational stability is inserted into the canal. A proximal body is then chosen that establishes the appropriate leg length, femoral offset, and version. The final proximal body is engaged into the fluted tapered stem. Finally, the fracture is fixed around the implant with a combination of cables or wires.

Alternatives

Historically, implants such as extensively porous coated stems were utilized to treat Vancouver B2 or B3 periprosthetic femoral fractures. Unfortunately, these implants were associated with high rates of failure and revision7,9.

Rationale

The introduction of a fluted tapered stem provided a more reliable implant that achieves immediate axial and rotational stability. In addition, utilizing a fluted tapered stem allowed for a more soft-tissue-preserving approach to these complex injuries, in turn allowing the fracture to be reduced around the implant proximally with cerclage cables and or wires. Modular fluted tapered stems provide the additional advantage of allowing the surgeon to modify leg length, offset, and femoral version, independently of the fluted tapered stem. As a result of these unique advantages, these stems were introduced several years ago for the treatment of Vancouver B2 or B3 periprosthetic femoral fractures.

Expected Outcomes

Contemporary series have demonstrated that the use of a modular fluted tapered stem leads to improved implant survivorship and clinical outcomes with lower complication rates for Vancouver B2 and B3 periprosthetic femoral fractures1,10-12,14-19.

Important Tips

Template both the fluted tapered stem and proximal body preoperatively. The proximal body should be templated at the ideal hip center of rotation that appropriately restores leg lengths and offset. Template the fluted tapered stem so that it provides appropriate isthmic fit and bypasses the most distal extent of the fracture by at least 2 cortical diameters.Utilize a modified extended trochanteric osteotomy for your exposure in order to facilitate visualization of the fracture and to provide direct access to the femoral canal.Place a prophylactic cable prior to preparing the femur for the implant in order to help prevent iatrogenic fracture.Place a trial stem and obtain intraoperative anteroposterior and lateral radiographs in order to assess the position of the implants and the risk of anterior cortical perforation.When placing the final implants, be sure the fluted tapered stem has both axial and rotational stability.Reduce and fix the fracture after the final implants are placed and the hip is reduced.

Acronyms and Abbreviations

AP = anteroposteriorMFT = modular fluted tapered (stem)ETO = extended trochanteric osteotomyTHA = total hip arthroplastyCT = computed tomographyPJI = periprosthetic joint infection.

Prospective randomized controlled trial on the accuracy of prosthesis positioning in total hip arthroplasty assisted by a newly designed whole-process robotic arm

INTRODUCTION

The purpose of this article is to study whether the newly designed whole-process total hip arthroplasty (THA) robotic arm can improve the accuracy of prosthesis placement in THA.

METHOD

In this study, 72 patients undergoing THA were prospectively included and randomly divided into two groups. The experimental group was treated with THA assisted by a newly designed robotic arm. The control group received THA with conventional surgical methods. The imaging data were compared after operation.

RESULT

Compared with the conventional operation, the whole-process robotic arm can more accurately place the acetabular prosthesis in the anteversion safe zone of 5 ~ 25°, but in terms of the inclination angle, whether the reference is the safe zone of 30 ~ 50° or 30 ~ 45°, there is no statistical difference between the two groups. The average lower limb length discrepancy (LLLD) in the experimental group was 3.77 ± 8.31 mm longer than contralateral side, while the counterpart in the control group was 8.39 ± 9.11 mm, with significant difference (P = 0.029). The femoral prosthesis was fixed in neutral position in 35 (100%) cases in the experimental group and only 30 (83.3%) in the control group (P = 0.036). There was no significant difference in the recovery of hip offset, femoral anteversion, and canal fill ratio (CFR) between the two groups.

CONCLUSION

Robotic arm can improve the accuracy of anteversion of acetabular cup, restore the consistency of the length of lower limbs, and more accurately implant the femoral prosthesis to the neutral position in the coronal position.

CLINICAL TRIAL REGISTRATION NUMBER

ChiCTR2100044124 (date of registration: 2021-3-11).

Profiling the Immune Response to Periprosthetic Joint Infection and Non-Infectious Arthroplasty Failure

Arthroplasty failure is a major complication of joint replacement surgery. It can be caused by periprosthetic joint infection (PJI) or non-infectious etiologies, and often requires surgical intervention and (in select scenarios) resection and reimplantation of implanted devices. Fast and accurate diagnosis of PJI and non-infectious arthroplasty failure (NIAF) is critical to direct medical and surgical treatment; differentiation of PJI from NIAF may, however, be unclear in some cases. Traditional culture, nucleic acid amplification tests, metagenomic, and metatranscriptomic techniques for microbial detection have had success in differentiating the two entities, although microbiologically negative apparent PJI remains a challenge. Single host biomarkers or, alternatively, more advanced immune response profiling-based approaches may be applied to differentiate PJI from NIAF, overcoming limitations of microbial-based detection methods and possibly, especially with newer approaches, augmenting them. In this review, current approaches to arthroplasty failure diagnosis are briefly overviewed, followed by a review of host-based approaches for differentiation of PJI from NIAF, including exciting futuristic combinational multi-omics methodologies that may both detect pathogens and assess biological responses, illuminating causes of arthroplasty failure.

A 92 protein inflammation panel performed on sonicate fluid differentiates periprosthetic joint infection from non-infectious causes of arthroplasty failure

Periprosthetic joint infection (PJI) is a major complication of total joint arthroplasty, typically necessitating surgical intervention and prolonged antimicrobial therapy. Currently, there is no perfect assay for PJI diagnosis. Proteomic profiling of sonicate fluid has the potential to differentiate PJI from non-infectious arthroplasty failure (NIAF) and possibly clinical subsets of PJI and/or NIAF. In this study, 200 sonicate fluid samples, including 90 from subjects with NIAF (23 aseptic loosening, 35 instability, 10 stiffness, five osteolysis, and 17 other) and 110 from subjects with PJI (40 Staphylococcus aureus, 40 Staphylococcus epidermidis, 10 Staphylococcus lugdunensis, 10 Streptococcus agalactiae, and 10 Enterococcus faecalis) were analyzed by proximity extension assay using the 92 protein Inflammation Panel from Olink Proteomics. Thirty-seven of the 92 proteins examined, including CCL20, OSM, EN-RAGE, IL8, and IL6, were differentially expressed in PJI versus NIAF sonicate fluid samples, with none of the 92 proteins differentially expressed between staphylococcal versus non-staphylococcal PJI, nor between the different types of NIAF studied. IL-17A and CCL11 were differentially expressed between PJI caused by different bacterial species, with IL-17A detected at higher levels in S. aureus compared to S. epidermidis and S. lugdunensis PJI, and CCL11 detected at higher levels in S. epidermidis compared to S. aureus and S. agalactiae PJI. Receiver operative characteristic curve analysis identified individual proteins and combinations of proteins that could differentiate PJI from NIAF. Overall, proteomic profiling using this small protein panel was able to differentiate between PJI and NIAF sonicate samples and provide a better understanding of the immune response during arthroplasty failure.

Modular Fluted Tapered Stems for Periprosthetic Femoral Fractures: Excellent Results in 171 Cases

BACKGROUND

Modular fluted tapered (MFT) stems have advanced treatment of Vancouver B2 and B3 periprosthetic femoral fractures, but series to date have been limited with respect to cohort size and follow-up duration. The purpose of this study was to determine implant survivorship, radiographic results, complications, and clinical outcomes of Vancouver B2 and B3 periprosthetic femoral fractures treated with MFT stems in a large series of patients.

METHODS

We identified 171 Vancouver B2 (109) and B3 (62) periprosthetic femoral fractures treated with an MFT stem between 2000 and 2018 using our institutional total joint registry. The mean age was 75 years, 50% were female, and the mean body mass index was 29 kg/m2. The median stem diameter was 18 mm and median stem length was 210 mm. The cumulative incidences of revision and reoperation with death as the competing risk were calculated, radiographs were reviewed, and clinical outcomes were evaluated using the Harris hip score (HHS). The mean follow-up was 5 years.

RESULTS

The 10-year cumulative incidence of any revision was 10%. There were 17 revisions, of which only 3 were for the distal fluted portion of the MFT stem. Revision indications included periprosthetic joint infection (PJI) (n = 6) and dislocation (n = 11). The 10-year cumulative incidence of any reoperation was 15%. In addition to the above 17 revisions, there were 7 reoperations for superficial wound complications (n = 4), Vancouver B1 periprosthetic femoral fracture (n = 1), vascular occlusion (n = 1), and acetabular cartilage degeneration requiring an acetabular component (n = 1). Radiographically, there was 1 fracture nonunion. All unrevised MFT stems were radiographically well fixed. Subsidence of ≥5 mm occurred in 11%, but all implants were stable at the most recent follow-up. The mean HHS was 75 at 2 years (n = 71).

CONCLUSIONS

In this large series of 171 Vancouver B2 and B3 periprosthetic femoral fractures treated with MFT stems, we found that such constructs were associated with a high rate of fracture healing and provided extremely reliable and durable implant fixation, with no revisions for aseptic loosening. Dislocation and PJI were the most common complications.

LEVEL OF EVIDENCE

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

Patient-reported outcome measures, complication rates, and re-revision rates are not associated with the indication for revision total hip arthroplasty : a prospective evaluation of 647 consecutive patients

AIMS

The aim of this study was to explore the relationship between reason for revision total hip arthroplasty (rTHA) and outcomes in terms of patient-reported outcome measures (PROMs).

METHODS

We reviewed a prospective cohort of 647 patients undergoing full or partial rTHA at a single high-volume centre with a minimum of two years' follow-up. The reasons for revision were classified as: infection; aseptic loosening; dislocation; structural failure; and painful THA for other reasons. PROMs (modified Oxford Hip Score (mOHS), EuroQol five-dimension three-level health questionnaire (EQ-5D-3L) score, and visual analogue scales for pain during rest and activity), complication rates, and failure rates were compared among the groups.

RESULTS

The indication for revision influenced PROMs improvement over time. This finding mainly reflected preoperative differences between the groups, but diminished between the first and second postoperative years. Preoperatively, patients revised due to infection and aseptic loosening had a lower mOHS than patients with other indications for revision. Pain scores at baseline were highest in patients being revised for dislocation. Infection and aseptic loosening groups showed marked changes over time in both mOHS and EQ-5D-3L. Overall complications and re-revision rates were 35.4% and 9.7% respectively, with no differences between the groups (p = 0.351 and p = 0.470, respectively).

CONCLUSION

Good outcomes were generally obtained regardless of the reason for revision, with patients having the poorest preoperative scores exhibiting the greatest improvement in PROMs. Furthermore, overall complication and reoperation rates were in line with previous reports and did not differ between different indications for rTHA. Cite this article: Bone Joint J 2022;104-B(7):859-866.

Pairing 40-mm Femoral Heads With the Smallest Compatible Acetabular Components in Total Hip Arthroplasty: Mid-Term Outcomes in 177 Cases

BACKGROUND

Contemporary total hip arthroplasty (THA) often employs larger femoral heads to optimize hip stability. However, pairing 40-mm femoral heads with the smallest compatible acetabular components poses a potential risk for implant failure. The purpose of this study is to evaluate the outcomes of primary THAs using 40-mm femoral heads and the smallest compatible acetabular components.

METHODS

Between 2007 and 2018, 177 primary THAs involving 40-mm femoral heads and acetabular components ≤56 mm with highly cross-linked polyethylene liners were identified. Mean age was 61 years, 56% were females, and mean body mass index was 32 kg/m². Cumulative incidences of dislocation, any revision, and any reoperation were determined utilizing a competing risk model. Osteolysis and femoral head penetration were assessed at minimum 8-year follow-up (n = 16). Mean follow-up was 6 years.

RESULTS

There were no cases of liner fractures or dissociations. The 10-year cumulative incidences of dislocation, any revision, and any reoperation were 3.6%, 4.2%, and 6.8%, respectively. Mean linear femoral head penetration was 0.01 mm/y and mean volumetric wear rate was 50 mm³/y. One THA demonstrated stable, asymptomatic periacetabular radiolucent lines at most recent follow-up.

CONCLUSION

In 177 primary THAs pairing 40-mm femoral heads with the smallest compatible acetabular components, there were no liner fractures or dissociations. The cumulative incidence of dislocation was modest at 10 years. The cumulative incidences of any revision and any reoperation were low at mid-term.

LEVEL OF EVIDENCE

IV.

Global Publication Trends and Research Hotspots of Revision Hip and Knee Arthroplasty: A 21-Year Bibliometric Approach

BACKGROUND

As the number of primary hip and knee arthroplasties increases, revision cases correspondingly demonstrate high relative growth, gaining increasing attention. The present research aimed to investigate subject characteristics in revision hip and knee arthroplasty (RHKA) research using a bibliometric approach.

METHODS

Publications related to RHKA from 2000 to 2020 were searched in the Web of Science database. WPS Office, CiteSpace, VOSviewer, and Bibliometrix were used to analyze the results.

RESULTS

Bibliometric analysis revealed 3290 records. Fifty-nine countries published manuscripts on RHKA. The United States contributed most and also had the highest number of international collaborations. The most relevant institution was the Mayo Clinic. Berry DJ and Parvizi J were the most productive and academic influential authors in RHKA, respectively. The most productive journal was the Journal of Arthroplasty. Co-occurrence analysis demonstrated "infection" to be the trend in RHKA. Thematic analysis displayed 16 keywords in hip arthroplasty and 14 keywords in knee arthroplasty.

CONCLUSION

The present study observed an increasing trend of research papers in RHKA. Institutions and scholars from the United States were found to dominate the field. Periprosthetic joint infection was likely a potential development trend and hotspot of RHKA.

Renal Toxicity Associated With Resection and Spacer Insertion for Chronic Hip PJI

BACKGROUND

Two-stage exchange arthroplasty with high-dose antibiotic-loaded bone cement spacer and intravenous (IV) antibiotics is the most common method of managing infected total hip arthroplasties. However, the contemporary incidence, risk factors, and outcomes of acute kidney injuries (AKIs) in this cohort are unknown.

METHODS

We identified 227 patients treated with 256 antibiotic-loaded bone cement spacers after resection of an infected primary total hip arthroplasty between 2000 and 2017. Mean age was 65 years, mean body mass index was 30 mg/kg², 55% were men, and 16% had pre-existing chronic kidney disease (CKD). Spacers were in situ for a mean of 15 weeks, concomitantly associated with IV or oral antibiotics for a mean of 6 weeks. AKI was defined as a creatinine ≥1.5X baseline or ≥0.3 mg/dL. Mean follow-up was 8 years.

RESULTS

AKI occurred in 13 patients without pre-existing CKD (7%) vs 10 patients with CKD (28%; OR 5; P = .0001). None required acute dialysis. Postoperative fluid depletion (β = 0.31; P = .0001), ICU requirement (β = 0.40; P = .0001), and acute atrial fibrillation (β = 0.43; P = .0001) were independent predictors for AKI in patients without pre-existing CKD. Duration of in situ spacer, mean antibiotic dose in cement, use of amphotericin B, and type of IV antibiotics were not significant risk factors. At last follow-up, 8 AKIs progressed to CKD, with one receiving dialysis 7 years later.

CONCLUSION

AKIs occurred in 7% of patients with normal renal function, with 5-fold greater risk in those with CKD, and 4% did develop CKD. Importantly, causes of acute renal blood flow impairment were independent predictors for AKI.

LEVEL OF EVIDENCE

Level III, comparative study.

Long-Term Outcomes for Cementless Anatomic Femoral Components, Compared by Area of Porous Coating, in Patients Younger Than 50 Years Treated for Hip Dysplasia

BACKGROUND

We investigated whether the proximal circumferential porous coating of cementless stems would make implant survival of >20 years possible in young patients.

METHODS

Data for patients younger than 50 years with hip dysplasia who had an anatomic stem implanted with a proximal porous coating with hydroxyapatite/tricalcium phosphate were reviewed. Noncircumferential porous (non-C-type) stems were used in 17 hips (13 cases), and circumferential porous (C-type) stems were used in 87 hips (68 cases). Acetabular components with conventional polyethylene were used for all hips. The mean ages at surgery for patients with non-C-type stems and those with C-type stems were 43.3 and 44.7 years, respectively. Stems that had not loosened were retained at the time of acetabular revision. The average duration of follow-up for patients with non-C-type stems was 26.9 years and was 22.3 years for those with C-type stems.

RESULTS

Mean survival rates as determined by the Kaplan-Meier method were 74.9% at 20 years and 59.9% at 25 years for non-C-type stems and were 100% at 20 years and 94.0% at 25 years for C-type stems. The survivorship for C-type stems was significantly higher than that for non-C-type stems (P < .01). Focal osteolysis in the shoulder of 37 hips with C-type stems suppressed the spread of osteolysis to the distal femur.

CONCLUSION

Anatomic femoral stems with a circumferential porous coating provide excellent durability in patients with hip dysplasia who are 50 years of age or younger.

LEVEL OF EVIDENCE

Therapeutic Level IV.

Inhibition of PAD4 mediated neutrophil extracellular traps prevents fibrotic osseointegration failure in a tibial implant murine model : an animal study

AIMS

Aseptic loosening is a leading cause of uncemented arthroplasty failure, often accompanied by fibrotic tissue at the bone-implant interface. A biological target, neutrophil extracellular traps (NETs), was investigated as a crucial connection between the innate immune system's response to injury, fibrotic tissue development, and proper bone healing. Prevalence of NETs in peri-implant fibrotic tissue from aseptic loosening patients was assessed. A murine model of osseointegration failure was used to test the hypothesis that inhibition (through Pad4^-/- mice that display defects in peptidyl arginine deiminase 4 (PAD4), an essential protein required for NETs) or resolution (via DNase 1 treatment, an enzyme that degrades the cytotoxic DNA matrix) of NETs can prevent osseointegration failure and formation of peri-implant fibrotic tissue.

METHODS

Patient peri-implant fibrotic tissue was analyzed for NETs biomarkers. To enhance osseointegration in loose implant conditions, an innate immune system pathway (NETs) was either inhibited (Pad4^-/- mice) or resolved with a pharmacological agent (DNase 1) in a murine model of osseointegration failure.

RESULTS

NETs biomarkers were identified in peri-implant fibrotic tissue collected from aseptic loosening patients and at the bone-implant interface in a murine model of osseointegration failure. Inhibition (Pad4^-/- ) or resolution (DNase 1) of NETs improved osseointegration and reduced fibrotic tissue despite loose implant conditions in mice.

CONCLUSION

This study identifies a biological target (NETs) for potential noninvasive treatments of aseptic loosening by discovering a novel connection between the innate immune system and post-injury bone remodelling caused by implant loosening. By inhibiting or resolving NETs in an osseointegration failure murine model, fibrotic tissue encapsulation around an implant is reduced and osseointegration is enhanced, despite loose implant conditions. Cite this article: Bone Joint J 2021;103-B(7 Supple B):135-144.

The Lawrence D. Dorr Surgical Techniques & Technologies Award: Using Big Heads and Small Acetabular Components With Highly Cross-Linked Polyethylene in Total Hip Arthroplasty: Is It Safe?

BACKGROUND

Contemporary total hip arthroplasty (THA) employs larger femoral heads to optimize hip stability. However, the combination of large femoral heads and comparatively small acetabular components poses a potential risk for implant failure secondary to polyethylene (PE) liner fracture or dissociation. The purpose of this study was to evaluate the incidence of liner fracture or dissociation, implant survivorship, and PE wear rates in primary THAs using large femoral heads and small acetabular components.

METHODS

Between 2000 and 2017, we retrospectively identified 882 primary THAs with 36 mm femoral heads and acetabular components ≤52 mm with highly cross-linked polyethylene liners. Mean age was 66 years, 88% were females, and mean body mass index was 30 kg/m². We evaluated the cumulative incidences of dislocation, any revision, and any reoperation utilizing a competing risk model. Osteolysis and femoral head penetration were assessed with a validated radiographic technique at minimum 10-year follow-up (n = 18). Mean follow-up was 4 years.

RESULTS

There were no liner fractures or dissociations in the entire cohort. The 10-year cumulative incidences of dislocation, any revision, and any reoperation were 3.2%, 5.6%, and 9.3%, respectively. Mean linear femoral head penetration was 0.042 mm/y and mean volumetric wear rate was 44 mm³/y. No THAs demonstrated evidence of osteolysis or component loosening at long-term follow-up.

CONCLUSION

In a large cohort of primary THAs pairing large femoral heads with small acetabular components, there was no evidence of liner fracture or dissociation. Cumulative incidences of dislocation, any revision, and any reoperation were low at mid-term.

LEVEL OF EVIDENCE

IV.

Isolated tibial insert exchange in revision total knee arthroplasty : reliable and durable for wear; less so for instability, insert fracture/dissociation, or stiffness

AIMS

This study aimed to determine outcomes of isolated tibial insert exchange (ITIE) during revision total knee arthroplasty (TKA).

METHODS

From 1985 to 2016, 270 ITIEs were performed at one institution for instability (55%, n = 148), polyethylene wear (39%, n = 105), insert fracture/dissociation (5%, n = 14), or stiffness (1%, n = 3). Patients with component loosening, implant malposition, infection, and extensor mechanism problems were excluded.

RESULTS

Survivorship free of any re-revision was 68% at ten years. For the indication of insert wear, survivorship free of any re-revision at ten years was 74%. Re-revisions were more frequent for index diagnoses other than wear (hazard ratio (HR) 1.9; p = 0.013), with ten-year survivorships of 69% for instability and 37% for insert fracture/dissociation. Following ITIE for wear, the most common reason for re-revision was aseptic loosening (33%, n = 7). For other indications, the most common reason for re-revision was recurrence of the original diagnosis. Mean Knee Society Scores improved from 54 (0 to 94) preoperatively to 77 (38 to 94) at ten years.

CONCLUSION

After ITIE, the risk and reasons for re-revision correlated with preoperative indications. The best results were for polyethylene wear. For other diagnoses, the re-revision rate was higher and the failure mode was most commonly recurrence of the original indication for the revision TKA. Cite this article: Bone Joint J 2021;103-B(6):1103-1110.

Metal ion levels with use of modular dual mobility constructs: Can the evidence guide us on clinical use?

Introduction

Dual mobility (DM) use in total hip arthroplasty (THA) has increased, particularly for prevention and management of instability. However, a modular interface raises concern for metal ion generation. The purpose of this study was to determine the 1) serum cobalt and chromium levels; 2) prevalence of ion levels >1 mcg/L; and 3) effect of femoral head material on ion levels following THA using modular DM bearings.

Methods

We performed a systematic review (MEDLINE, Embase, Cochrane databases) for articles relating to metal ion levels and modular DM (MDM) THA. Eight studies (290 patients) met the inclusion criteria. We recorded post-operative ion levels at a minimum of 12 months, and compared levels with ceramic (n = 125) and metal femoral heads (n = 165). A meta-analysis could not be performed due to poor study quality and heterogeneity.

Results

At average follow-up of 30.4 months, mean cobalt level was 0.71 mcg/L, and mean chromium level was 0.66 mcg/L [22 patients (8%) had elevated ion levels above 1 mcg/L]. When compared to MDM with a ceramic head, metal head use had higher cobalt (1.26 vs. 0.42 mcg/L) and chromium levels (1.23 vs. 0.46 mcg/L). MDM with a metal head was 1.30 times more likely to have elevated ion levels >1 mcg/L. There was no effect of ion levels on outcome scores.

Conclusions

Measurable elevations of serum cobalt and chromium levels are present in patients with well-functioning MDM THAs. The impact and contributions of the additional metal liner interface are still unclear. The use of a ceramic head appears to mitigate ion release, while reducing other mechanisms of metallosis like taper corrosion. Higher quality studies are necessary to understand whether MDM bearings pose long term issues. Until then, the judicious use of MDM articulations is recommended.

Contemporary indications for first-time revision surgery after primary cementless total hip arthroplasty with emphasis on early failures

BACKGROUND

To clarify contemporary indications for first-time revision surgery after primary cementless total hip arthroplasty (THA) for addressing potential issues with cementless THA.

METHODS

Data for 101 consecutive hips in 94 patients who underwent primary cementless THA at our institution and subsequently underwent first-time revision surgery were retrospectively reviewed. Baseline characteristics, indications for first-time revision surgery, and time from the primary THA to first-time revision surgery were evaluated.

RESULTS

The overall mean time to first-time revision surgery was 10.3 years (range, 0-33 years). The indications for first-time revision surgery were polyethylene wear and osteolysis in 33 hips, aseptic loosening in 25 hips, infection in 17 hips, periprosthetic fracture in 13 hips, instability in 8 hips, and component failure (liner dissociation or stem fracture) in 5 hips. Thirty-seven hips (37%) had undergone first-time revision surgery within 5 years of primary THA, of which the most common indications were infection and periprosthetic fracture.

CONCLUSION

The current results suggested that reducing the number of early failures seems to be essential form improving THA outcomes.

The FAITH and HEALTH Trials: Are We Studying Different Hip Fracture Patient Populations?

BACKGROUND

Over the past decade, 2 randomized controlled trials were performed to evaluate 2 surgical strategies (internal fixation and arthroplasty) for the treatment of low-energy femoral neck fractures in patients aged ≥50 years. We evaluated whether patient populations in both the FAITH and HEALTH trials had different baseline characteristics and compared the displaced femoral neck fracture cohort from the FAITH trial to HEALTH trial patients.

METHODS

Patient demographics, medical comorbidities, and fracture characteristics from both trials were compared. FAITH trial patients with displaced fractures were then compared with HEALTH patients. T-tests and χ tests were performed to compare differences for sex, age, osteoporosis status, and ASA class.

RESULTS

The mean age of the 1079 FAITH trial patients was 72 versus 79 years for the 1441 HEALTH trial patients. HEALTH patients were older, mostly White, used more medication, and had more comorbidities than FAITH patients. Of the 1079 FAITH trial patients, 32% (346/1079) had displaced fractures. Their mean age was significantly lower than that of HEALTH patients (66 vs. 79 years; P < 0.001). HEALTH trial patients were significantly more likely to be female, have ASA classification Class III/IV/V, and carry a diagnosis of osteoporosis, as compared with the subgroup of FAITH patients with displaced femoral neck fractures (P < 0.001).

CONCLUSION

This study demonstrates significant differences between patients enrolled in the 2 trials. Although both studies focused on femoral neck fractures with similar enrollment criteria, patient populations differed. This sheds light on a noteworthy limitation of discordant patient enrollment into randomized trials, despite similar eligibility criteria.

LEVEL OF EVIDENCE

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

Utilization of Debridement, Antibiotics, and Implant Retention for Infection After Total Joint Arthroplasty Over a Decade in the United States

BACKGROUND

Reported clinical outcomes have varied for debridement, antibiotics, and implant retention (DAIR) and little is known regarding trends in utilization. We sought to evaluate the rate of DAIR utilization for total knee arthroplasty (TKA) and total hip arthroplasty (THA) periprosthetic joint infection (PJI) over a decade and clinical factors associated with these trends.

METHODS

A retrospective study of primary TKAs and THAs was performed using Medicare data from 2005 to 2014 using the PearlDiver database platform. Current Procedural Technology and International Classification of Diseases Ninth Edition codes identified patients who underwent a surgical revision for PJI, whether revision was a DAIR, as well as associated clinical factors including timing from index arthroplasty.

RESULTS

The proportion of revision TKAs and THAs performed using DAIR was 27% and 12% across all years, respectively. This proportion varied by year for TKAs and THAs with a linear trend toward increasing relative use of DAIR estimated at 1.4% and 0.9% per year (P < .001; P < .001). DAIR for TKA and THA performed within 90 days increased at a faster rate, 3.4% and 2.1% per year (P < .001; P < .001). Trends over time in TKA DAIRs showed an association with Elixhauser Comorbidity Index (ECI), 0-5 group increasing at 2.0% per year (P = .03) and patients >85 years (P = .04).

CONCLUSION

The proportion of revision arthroplasty cases for PJI managed with DAIR has been increasing over time in the United States, with the most substantial increase seen <90 days from index arthroplasty. Age, gender, and ECI had a minimal association with this trend, except in the TKA population >85 years and in those with a very low ECI score.

The Use of Cement in Hip Arthroplasty: A Contemporary Perspective

Notable advances in hip arthroplasty implants and techniques over the past 60 years have yielded excellent survivorship of fully cemented, hybrid, and reverse hybrid total hip replacements as demonstrated in joint registries worldwide. Major advances in noncemented implants have reduced the use of cement, particularly in North America. Noncemented implants predominate today based on procedural efficiency, concern related to thromboembolic risk, and a historic belief that cement was the primary cause of osteolysis and implant loosening. With the decline of cemented techniques, press-fit fixation has become common even in osteoporotic elderly patients. Unfortunately, there is a troubling rise in intraoperative, as well as early and late postoperative periprosthetic fractures associated with the use of noncemented implants. Despite the success of noncemented fixation, an understanding of modern cement techniques and cemented implant designs is useful to mitigate the risk of periprosthetic fractures. Cemented acetabular components can be considered in elderly patients with osteoporotic or pathologic bone. Cemented stems should be considered with abnormal proximal femoral morphology, conversion of failed hip fixation, inflammatory arthritis, patient age over 75 (especially women), osteoporotic bone (Dorr C), and in the treatment of femoral neck fractures.