Underwent Revision THA Research Articles

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

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. (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? 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. 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. 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 II, diagnostic study.

Is Timing of Total Hip Arthroplasty and Lumbar Spine Fusion Associated With Risk of Hip Dislocation?

In patients with concomitant hip and lumbar spine disease, the question of which surgery-total hip arthroplasty (THA) or lumbar spine fusion (LSF)-to address first has not been adequately answered. We aimed to evaluate the risk of dislocation after THA in patients with LSF first or after THA. Retrospective review utilizing the PearlDiver database querying Current Procedural Terminology codes for LSF in the year prior (LSF first) or in the year after primary or revision THA (THA first). International Classification of Disease codes identified postoperative hip dislocation as our primary outcome variable. Demographic data collected included age, sex, and obesity. Dislocation rates were described as a proportion of the cohort and compared with chi-square tests. We identified 280,857 primary THA and 42,314 revision THA cases from 2012-2019. Of these, 2090 underwent primary THA and LSF, and 283 underwent revision THA and LSF within a year of each procedure. No differences in age, sex, or obesity between groups were noted. No difference in rate of all-time dislocation for primary THA was noted for the LSF first 51/1429 (3.6%) compared to the THA first 30/661 (4.0%) groups (P= .34), or for revision THA with LSF first 48/204 (23.5%) compared to THA first 27/117 (23.1%) groups (P= 1.0). There was no difference in the risk of dislocation after primary or revision THA if LSF occurred prior to or after the THA. These findings can help surgeons as they counsel patients with concomitant lumbar spine and hip degeneration.

LONG-TERM OUTCOMES OF REVISION TOTAL HIP ARTHROPLASTY WITH A MODULAR REVISION HIP SYSTEM: A HIGH-VOLUME SINGLE-CENTRE EXPERIENCE

The purpose of this study was to determine long-term survival free from all-cause revision and stem-related failure, as well as radiographic and functional outcomes of the ZMR stem in revision THA.We retrospectively identified all patients in our institutional database who underwent revision THA using the ZMR Revision Hip system from the year 2000 to 2007 (minimum two-year follow-up). Of the 112 ZMR hips (110 patients) identified, a total of 106 hips (104 patients) met inclusion criteria. The mean study follow-up 13.9 years (range 2–22). Indications for index ZMR revision included aseptic loosening (72.1%), periprosthetic joint infection (17.3%), periprosthetic fracture (9.6%), and stem fracture (1.0%). Kaplan-Meier analysis was used to determine the all-cause and stem-related failure revision-free survival. Validated patient reported outcomes were collected and available radiographs were reviewed to determine implant stability.A total of 17 hips (16.0%) underwent a re-revision of any component. The indications for re-revision were stem failure (35.3%), infection (29.4%), instability (29.4%), and aseptic loosening of the acetabular component (5.9%). The five- and 15-year all-cause survivorship was 89.5% (95% CI 86.5–92.5) and 83.0% (95% CI 79.2–86.8), respectively. There were six re-revisions for stem failure (5.7%); five for stem fracture and one for aseptic loosening. The average time to stem failure was 4.6 years (range 1.3–8.2). The five- and 15-year survivorship free from stem-related failure was 97.2% (95% CI 95.6–98.8) and 93.9% (95% CI 91.5–96.3), respectively. At final follow-up the mean Oxford hip score was 36.9 and all surviving ZMR stems were well fixed on radiographs.Femoral revision with the ZMR stem offers satisfactory long-term survivorship and promising clinical outcomes. Although uncommon, stem fracture was the most common reason for stem-related failure.

Depression and anxiety are associated with an increased risk of infection, revision, and reoperation following total hip or knee arthroplasty.

The aim of this study was to determine the prevalence of depressive and anxiety disorders prior to total hip (THA) and total knee arthroplasty (TKA) and to assess their impact on the rates of any infection, revision, or reoperation. Between January 2000 and March 2019, 21,469 primary and revision arthroplasties (10,011 THAs; 11,458 TKAs), which were undertaken in 15,504 patients at a single academic medical centre, were identified from a 27-county linked electronic medical record (EMR) system. Depressive and anxiety disorders were identified by diagnoses in the EMR or by using a natural language processing program with subsequent validation from review of the medical records. Patients with mental health diagnoses other than anxiety or depression were excluded. Depressive and/or anxiety disorders were common before THA and TKA, with a prevalence of 30% in those who underwent primary THA, 33% in those who underwent revision THA, 32% in those who underwent primary TKA, and 35% in those who underwent revision TKA. The presence of depressive or anxiety disorders was associated with a significantly increased risk of any infection (primary THA, hazard ratio (HR) 1.5; revision THA, HR 1.9; primary TKA, HR 1.6; revision TKA, HR 1.8), revision (THA, HR 1.7; TKA, HR 1.6), re-revision (THA, HR 2.0; TKA, HR 1.6), and reoperation (primary THA, HR 1.6; revision THA, HR 2.2; primary TKA, HR 1.4; revision TKA, HR 1.9; p < 0.03 for all). Patients with preoperative depressive and/or anxiety disorders were significantly less likely to report "much better" joint function after primary THA (78% vs 87%) and primary TKA (86% vs 90%) compared with those without these disorders at two years postoperatively (p < 0.001 for all). The presence of depressive or anxiety disorders prior to primary or revision THA and TKA is common, and associated with a significantly higher risk of infection, revision, reoperation, and dissatisfaction. This topic deserves further study, and surgeons may consider mental health optimization to be of similar importance to preoperative variables such as diabetic control, prior to arthroplasty.

How Often Do Complications and Mortality Occur After Operatively Treated Periprosthetic Proximal and Distal Femoral Fractures? A Register-based Study.

The incidence of periprosthetic femoral fractures is increasing because of an increasing number of primary THAs and TKAs. High rates of complications and mortality are associated with periprosthetic fractures, but few studies have evaluated and compared the population-based incidences of these events after fractures. (1) What is the annual incidence of periprosthetic fractures treated with surgery in one hospital district in Finland? (2) How are those incidences changing over time? (3) What is the risk of complications, reoperations, and death after those injuries? This register-based study evaluated 2259 patients who underwent revision THA or TKA or any surgery for a femoral fracture between January 2004 and December 2016 at the only hospital in our district where these types of operations are performed. During the study period, the diagnosis and operation codes of the operated-on patients varied greatly, and they were somewhat inaccurate. We thus evaluated radiographs of all 2259 patients one by one, and created inclusion and exclusion criteria based on radiologic findings and medical records. Of those, 12% (279 of 2259) had periprosthetic fractures that met the inclusion criteria, and from these, we formed two study groups (periprosthetic proximal femur fractures, n = 171; periprosthetic distal femur fractures, n = 108). Eighty-eight percent (1980 of 2259) of the patients were excluded because they were treated for a condition other than periprosthetic femoral fracture. The follow-up period ended in December 2019 or at the time the patient died. To evaluate the population-based incidence, we drew the number of individuals with THA or TKA in the hospital district from the Finnish Arthroplasty Register and the Finnish Hospital Discharge Register. The characteristics of patients with operatively treated periprosthetic femoral fractures were evaluated in terms of age, gender, fracture type, implant type, and time from the index operation to periprosthetic fracture. The annual incidences of periprosthetic femoral fractures are summarized per 1000 person-years of individuals living with an implanted THA or TKA and per 100,000 individuals per year living in our hospital district. The risks of death, complications, and reoperations were evaluated for both groups, and comparisons were made in terms of patient characteristics. The mean annual incidence of operatively treated periprosthetic proximal femur fractures per 1000 people living with THA implants was 2.3 ± 0.9 (95% confidence interval 1.8 to 2.7) per year, and for those with periprosthetic distal femur fractures with TKA implants, it was 1.3 ± 0.6 (95% CI 1.0 to 1.7). There was an increasing trend in the incidence of periprosthetic proximal femur fractures from 1.6 to 3.8 (95% CI 1.8 to 2.8) per 1000 arthroplasties, and it increased from 0.4 to 1.7 (95% CI 2.4 to 4.4) for periprosthetic distal femur fractures between 2004 and 2016. The mean population-based incidence of periprosthetic proximal femur fractures per 100,000 person-years was 5.3 ± 2.2 (95% CI 4.1 to 6.4) per year, and for periprosthetic distal femur fractures, it was 3.4 ± 1.7 (95% CI 2.5 to 4.4). The incidence of periprosthetic proximal femur fractures related to 100,000 person-years increased from 3.2 to 8.9 (95% CI 3.9 to 6.6), while the incidence of periprosthetic distal femur fractures increased from 1.3 to 4.4 (95% CI 2.4 to 4.8) during the study period. The cumulative incidence of major complications after periprosthetic proximal femur fracture was 8.8% at 1 year (95% CI 5.1% to 13.6%) and 12.3% at 10 years (95% CI 7.5% to 18.4%), and after periprosthetic distal femur fracture, it was 7.4% at 1 year (95% CI 3.5% to 13.4%) and 9.3% at 10 years (95% CI 4.7% to 15.7%). The cumulative incidence of reoperation after periprosthetic proximal femur fracture was 10.5% at 1 year (95% CI 6.5% to 15.7%) and 13.5% at 10 years (95% CI 8.9% to 19.1%), and for periprosthetic distal femur fracture, it was 8.3% at 1 year (95% CI 4.1% to 14.5%) and 13.8% at 10% years (95% CI 7.8% to 21.4%). The cumulative incidence of death after periprosthetic proximal femur fracture was 8.2% at 1 year (95% CI 4.7% to 12.9%) and 47.3% at 10 years (95% CI 38.1% to 55.9%), and after periprosthetic distal femur fractures, it was 14.8% at 1 year (95% CI 8.8% to 22.2%) and 67.8% at 10 years (95% CI 56.3% to 76.9%). The increased use of THA and TKA has led to an increase in the incidence of operatively treated periprosthetic fractures, which means there will be more revisions in the future. Older age, frailty of these patients, and often-complicated fracture patterns are related to a high rate of complications, reoperations, and mortality. Healthcare systems must prepare for a large increase in revisions for periprosthetic fracture, which are morbid events for patients and costly ones for healthcare systems. Level III, therapeutic study.

Short Term Outcomes (Average Follow-Up of 2.4 Years) of a Constrained Acetabular Liner in Primary and Revision Total Hip Arthroplasty

BackgroundAs instability continues to be a burden post-total hip arthroplasty (THA), there has been a controversial discussion on the ideal implant choice. We report the outcomes of a modern constrained acetabular liner (CAL) system in primary and revision THA at an average follow-up of 2.4 years. MethodsWe performed a retrospective study of all patients undergoing primary and revision hip arthroplasty and being implanted with the modern CAL system from 2013 to 2021. We identified 31 hips, of which 13 underwent primary THA and the remaining 18 underwent revision THA for instability. ResultsOf those implanted with CAL primarily, 3 had concomitant abductor tear repair and gluteus maximus transfer, 5 had Parkinson’s disease, 2 had inclusion body myositis, 1 had amyotrophic lateral sclerosis, and the remaining two were over 94 years of age. All patients implanted with the CAL had active instability post-primary THA and underwent only liner and head exchange without revision of the acetabular or femoral components. At an average follow-up of 2.4 years (ranging from 9 months to 5 years and 4 months), we had 1 case (3.2%) of dislocation post-CAL implantation. None of the patients undergoing surgery with CAL for active instability had a redislocation. ConclusionIn conclusion, a CAL provides excellent stability in both primary THA in high-risk individuals and revision THA in cases of active instability. There were no dislocations when using a CAL to treat active instability post-THA.

Extended Ischiopubic Fixation Using Porous Metal Augments in Cementless Acetabular Reconstruction during Revision Total Hip Arthroplasty.

ObjectivesThe aims of this study were to introduce the definition, indication, and surgical technique of extended ischiopubic fixation (EIF) and to investigate the early clinical, radiographic results and complications of hips revised with EIF.MethodsPatients who underwent revision THA utilizing the technique of EIF which was defined as securing the porous metal augment >5 mm deep into the ischium and/or pubic ramus to gain adequate mechanical support and fresh host bone for bony ingrowth in a single institution from February 2015 to February 2020 were retrospectively reviewed. After applying the inclusion and exclusion criteria, a total of 30 hips (28 patients) were eligible for the study and were enrolled. Four patients were lost to follow‐up postoperatively. The data of the remaining 24 patients (26 hips) were analyzed. The patients' clinical results were assessed using of the Harris Hip Score and any complications including postoperative periprosthetic joint infection, intraoperative fracture, postoperative periprosthetic fracture, dislocation, nerve palsy, hematoma or wound complication were documented. The radiographic results were assessed with the construct stability, the position of the center of rotation, and cup orientation.ResultsThe median age of these 25 patients was 62.00 (interquartile: 54.25–68.25) years, with a median body mass index (BMI) of 22.60 kg/m2 (interquartile: 21.49–25.12 kg/m2). A total of 12 (48%) patients were female. At a median duration of follow‐up of 49.16 months, 20 (80%) patients rated their satisfaction level as “very satisfied,” five (20%) were “satisfied.” The median HHS improved from 36.00 (interquartile range: 31.25–49.75) preoperatively to 81.00 (interquartile range: 74.75–88.25) at the most recent follow‐up (p < 0.001). No complications such as periprosthetic joint infection, intraoperative fracture, periprosthetic fracture, dislocation, nerve palsy, hematoma, or wound complication were identified. All constructs were considered to have obtained stable fixation. The median vertical and horizontal distance between the latest postoperative centers of rotation to the anatomic center of rotation improved from 13.62 and 8.68 mm preoperatively to 4.42 and 4.19 mm at final follow‐up (p < 0.001).ConclusionsEarly follow‐up of patients reconstructed with porous metal augments using the EIF technique demonstrated satisfactory clinical results with no particular complications, stable fixation, and restoration of the center of rotation.

What is the Accuracy of a Rapid Strip Test That Detects D-lactic Acid in Synovial Fluid for the Diagnosis of Periprosthetic Joint Infections?

D-lactic acid is a specific marker produced almost exclusively by bacterial species; thus, the appearance of this marker in synovial fluid may indicate periprosthetic joint infection (PJI). Recently, studies have investigated the accuracy of enzyme-linked laboratory tests that detect D-lactic acid in synovial fluid to diagnose PJI. However, to our knowledge, no studies have determined the usefulness of rapid strip tests that detect D-lactic acid in synovial fluid in the diagnosis of PJI. (1) What is the best cutoff value for the rapid D-lactic acid strip test for diagnosing PJI? (2) What are the diagnostic accuracies (sensitivity, specificity, positive predictive value [PPV], and negative predictive value [NPV]) of the rapid D-lactic acid strip test and two different rapid leukocyte esterase (LE) strip tests? This prospective study enrolled 157 patients who underwent revision THA or TKA from May 2021 to February 2022 at a single orthopaedic center. Seventy percent (110 of 157) were eligible for analysis; 10% of these patients (15 of 157) were excluded based on the exclusion criteria (causes of revisions and additional comorbidities that may interfere with the results), and 20% (32 of 157) of the synovial fluid samples could not be tested (dry taps and blood-contaminated samples that could not be centrifuged). We performed the following off-label diagnostic tests on synovial fluid samples collected from all patients: the D-lactic acid strip test (QuantiQuick TM , BioAssay System), two different LE strip tests (10 EA from ARKRAY and BM 10 from BioMaxima). Differently colored strips were marked with symbols (from [-] to [++++] for D-lactic acid and from [-] to [+++] for LE tests) according to the manufacturers' instructions. For the LE tests, results were different for (++), which corresponds to a minimal value of 250 leu/mL for 10 EA and 125 leu/mL for BM 10 tests. The diagnostic standard for the presence or absence of PJI in this study was the International Consensus Meeting (ICM) 2018 criteria; based on these criteria (without the application of an LE test as a minor criterion), all patients were assessed and divided into two groups. Patients who did not meet the criteria for PJI and underwent revision for aseptic loosening, implant malposition, instability, or implant damage were included in the aseptic revision total joint arthroplasty group (68 patients). Patients with a fistula penetrating the joint, those with two positive culture results of the same pathogen, or those with ≥ 6 points according to ICM 2018 minor criteria were enrolled in the PJI group (42 patients). To ascertain the best cutoff value for the rapid D-lactic acid and both LE strip tests for diagnosing PJI, we used collected results, generated a receiver operating characteristic curve, and calculated the Youden index. To determine the accuracies of the diagnostic tests, we calculated their sensitivities, specificities, PPVs, and NPVs against the diagnostic standard (the ICM 2018 criteria). The best cutoff value for D-lactic acid was 22.5 mg/L, which corresponded to a reading of (+) on the test strip. For D-lactic acid, in the diagnosis of PJI, the sensitivity was 83% (95% confidence interval [CI] 68% to 92%) and specificity was 100% (95% CI 93% to 100%). For both LE strip tests, the best cutoff value was the same as that proposed in the ICM 2018 criteria. For LE (10 EA), the sensitivity was 81% (95% CI 66% to 91%) and specificity was 99% (95% CI 91% to 100%); for LE (BM 10), sensitivity was 81% (95% CI 65% to 91%) and specificity was 97% (95% CI 89% to 100%). A rapid off-label D-lactic acid strip test is valuable for diagnosing PJI. The results of this study indicate very good accuracy with comparable sensitivity and specificity for both LE strip tests. The usefulness of the test in a group of patients with chronic inflammatory diseases and the reproducibility of the reading by different researchers were not analyzed in this study and require further investigations. Before a rapid D-lactic strip test is routinely used for diagnosing PJI, multicenter studies on a larger group of patients should be conducted.Level of Evidence Level II, diagnostic study.

Revision Total Hip Arthroplasty Using the Modular Proximal Stem Modified for Asians: Medium-Term Clinical Results and Perioperative Complications.

This study aimed to examine the medium-term clinical and radiological outcomes of revision THA using the S-ROM-A stem, a modification of the S-ROM stem intended for Asians. Femoral reconstruction using the S-ROM-A stem was performed in 126 hips that underwent revision THA. All patients were followed for perioperative complications. In addition, clinical and radiographic outcomes at a mean of 8 (range 5-14) years postoperatively were evaluated in 96 hips of 86 patients (76%). The most common perioperative complication was a femoral fracture, occurring in 16 hips (13%), including 11 intraoperative and 5 postoperative fractures. Dislocation occurred in five hips (4.0%), infection in three hips (2.4%), and trunnionosis in two hips (1.6%), including late complications. The total second stem revision was performed in two hips while stem only second revision preserving the bone ingrown sleeve was performed in four hips. With a second revision for aseptic loosening as the endpoint, the 13-year stem survival rate was 100%. Hip function as assessed by the Japanese Orthopedic Association score improved from a mean of 48 points preoperatively to 87 points 8 years postoperatively (P < .05). Radiological evaluation at the final follow-up showed that 95 hips (99%) achieved bone ingrowth fixation and one hip (1%) achieved fibrous stable status. Revision THA using the S-ROM-A stem resulted in good medium-term outcomes. Although modifications of the stem length and shape may be effective in preventing fractures in Asians with relatively small body sizes, attention should be paid to the occurrence of trunnionosis, which may be associated with the decreased taper size.

What Is the Impact of Automated Synovial Cell Counting on Different Aseptic Causes and Periprosthetic Conditions Associated With Revision THA?

Studies have suggested that automated synovial cell counting may overestimate the white blood cell (WBC) count, resulting in false positive tests when evaluating patients for the possibility of periprosthetic joint infection (PJI) after THA. However, associations between WBC counts high enough to mimic PJI in patients whose arthroplasties are not infected but rather are experiencing a variety of aseptic problems-including but not limited to metallosis, polyethylene wear, and recurrent dislocation-have not, to our knowledge, been adequately addressed. In addition, there is a lack of analyses about the polymorphonuclear percentage (PMN%) when assessed by automated analyzers in this context. In the context of different indications for aseptic revision and different periprosthetic hip pathologic findings, we asked: (1) What were the synovial WBC count levels, and what proportion of values were above the 2018 International Consensus Meeting (ICM) cutoff (3000 cells/μL)? (2) What were the synovial PMN% levels, and what proportion of values were above the 2018 ICM (70%)? We retrospectively studied the preoperative cell count analyses of synovial fluid in patients who underwent revision THA for aseptic reasons at our tertiary referral arthroplasty center between January 2015 and December 2017. We considered all revisions performed on patients during that time potentially eligible, and after prespecified exclusions were applied (exclusions mainly included 15% [197 of 1306] sporadic missing data and 12% [155 of 1306] insufficient synovial fluid obtained in the aspirate), a total of 702 patients undergoing revision THA for aseptic reasons remained for the final analysis. As far as we know, no patients underwent re-revision for PJI at a mean follow-up of 46 ± 11 months, which tends to confirm our impression that indeed these hips did not have PJI. Cell count analyses were conducted using an automated analyzer. Clinical findings, preoperative radiographs, and surgical reports--confirmed by available histologic results--were used to establish diagnoses. We evaluated these hips considering the recommendations of the 2018 ICM (WBC count of 3000 cells/μL and PMN% of 70%) to see what proportion of them would have been characterized as likely having PJI on basis of those cutoff values. The mean WBC count for the entire cohort was 2120 ± 2395 cells/μL. The mean PMN% for the entire cohort was 36% ± 22%. Compared with aseptic loosening and recurrent dislocation, polyethylene wear had the highest mean WBC count (3817 ± 3711 cells/μL; p < 0.001). Of the investigated periprosthetic conditions, wear-induced synovitis had the highest value (4464 ± 3620 cells/μL; p < 0.001). Considering the ICM threshold, polyethylene wear showed the highest proportion of WBC counts above 3000 cells/μL among the indications for aseptic revision (60% [25 of 42]; p < 0.001). Of the periprosthetic conditions, wear-induced synovitis showed the highest proportion beyond the ICM cutoff (60% [50 of 83]; p < 0.001). The mean PMN% for aseptic causes ranged between 28% and 44% without differences among them (p = 0.12). Patients with metallosis had the highest mean PMN% of the periprosthetic conditions investigated (45% ± 25%; p = 0.007). Regarding the ICM threshold, metallosis resulted in the largest proportion of patients with a PMN% above 70% (21% [10 of 47]; p = 0.003), and that for wear-induced synovitis was 6% (5 of 83; p = 0.42) and for osteolysis was 3% (1 of 33; p = 0.51). There were no differences among aseptic loosening, recurrent dislocation, and polyethylene wear in terms of the proportion above 70% among the aseptic revision causes. Using automated cell counting, we found that WBC counts differ widely across indications for aseptic revision THA, and a high proportion of patients who underwent revision THA for aseptic reasons had WBC counts above the commonly used threshold of 3000 cells/μL. However, the PMN% was much less affected in several common indications for aseptic revision THA, making this measure more reliable for interpreting aspiration results using an automated analyzer. Based on the data distributions we observed, manual counting techniques might be considered in particular among patients with polyethylene wear, metal-on-metal bearing surfaces, or suspected metallosis. However, an elevated WBC count alone, observed using an automated analyzer in the context of polyethylene wear, should not be considered to be strongly suggestive of PJI, since that finding occurred so commonly among patients without infection. Level III, diagnostic study.

Evaluation of the feasibility of acetabular cup pre-determination in revision total hip arthroplasty via X-ray of the bone stock of the anterosuperior acetabulum

PurposeThis study was aimed to explore (1) location on AP pelvic X-ray that displayed bone stock in anterosuperior acetabulum; (2) whether X-ray could provide enough evidence to evaluate whether bone stock could provide support for acetabular cup; (3) criteria to determine whether anterosuperior bone stock could provide sufficient support for cup on X-ray.MethodsOur study retrospectively collected 43 patients who underwent revision THA for cup loosening from 2014 to 2019. The position of anterosuperior acetabular bone stock was compared between X-ray and CT-based 3-D reconstruction. Seventy-millimeter acetabular cup was implanted simulatively to obtain the contact line between acetabular cup and superolateral remaining bone stock. The contact line length and the angle were measured. Patients were divided into cup group and cage group, and ROC curves of both contact line length and angle were drawn.ResultsThe superolateral part of acetabulum on X-ray could reflect the anterosuperior host bone stock of acetabulum according to the comparison of anteroposterior pelvic X-ray and 3-D reconstruction. Critical point was chosen when we got the highest sensitivity with a 100% specificity in ROC curves. The critical values of contact length and angle were 15.58 mm and 25.5°.ConclusionsSurgeons could assess the anterosuperior bone stock of acetabulum by AP pelvic X-ray to decide whether revision could be done merely using cup or need customized cage. Clinically, when contact line length was larger than 16 mm or contact angle was larger than 25.5°, adoption of cup could obtain primary stability in the revision surgery in most cases.

Saline lavage after a "dry tap".

In patients with a "dry" aspiration during the investigation of prosthetic joint infection (PJI), saline lavage is commonly used to obtain a sample for analysis. The aim of this study was to investigate prospectively the impact of saline lavage on synovial fluid analysis in revision arthroplasty. Patients undergoing revision hip (THA) or knee arthroplasty (TKA) for any septic or aseptic indication were enrolled. Intraoperatively, prior to arthrotomy, the maximum amount of fluid possible was aspirated to simulate a dry tap (pre-lavage) followed by the injection with 20 ml of normal saline and re-aspiration (post-lavage). Pre- and post-lavage synovial white blood cell (WBC) count, percent polymorphonuclear cells (%PMN), and cultures were compared. A total of 78 patients had data available for analysis; 17 underwent revision THA and 61 underwent revision TKA. A total of 16 patients met modified Musculoskeletal Infection Society (MSIS) criteria for PJI. Pre- and post-lavage %PMNs were similar in septic patients (87% vs 85%) and aseptic patients (35% vs 39%). Pre- and post-lavage synovial fluid WBC count were far more disparate in septic (53,553 vs 8,275 WBCs) and aseptic (1,103 vs 268 WBCs) cohorts. At a cutoff of 80% PMN, the post-lavage aspirate had a sensitivity of 75% and specificity of 95%. At a cutoff of 3,000 WBCs, the post-lavage aspirate had a sensitivity of 63% and specificity of 98%. As the post-lavage synovial WBC count increased, the difference between pre- and post-lavage %PMN decreased (mean difference of 5% PMN in WBC < 3,000 vs mean difference 2% PMN in WBC > 3,000, p = 0.013). Of ten positive pre-lavage fluid cultures, only six remained positive post-lavage. While saline lavage aspiration significantly lowered the synovial WBC count, the %PMN remained similar, particularly at WBC counts of > 3,000. These findings suggest that in patients with a dry-tap, the %PMN of a saline lavage aspiration has reasonable sensitivity (75%) for the detection of PJI. Cite this article: Bone Joint J 2020;102-B(6 Supple A):138-144.

What Is the Survivorship of Revision Surgery Performed for the Chronically Dislocated THA?

Instability remains one of the most common indications for revision THA. However, little is known about the efficacy of surgery for and the complications associated with revision THA for patients with a chronically dislocated THA, which we define as a dislocation of more than 4 weeks. For patients with a chronically dislocated THA undergoing revision THA, we asked (1) What is the survivorship free from additional revision for these procedures? (2) What complications are associated with revision THA in this setting? (3) What are the clinical outcomes as measured by the Harris hip score in these procedures? From 1998 to 2014, 1084 patients who underwent revision THA for instability were reviewed and 33 patients (33 hips) were identified who had a hip that had been dislocated for more than 4 weeks. Median time dislocated was 4 months (range, 1-120 months), and the mean distance of the femoral head above hip center at presentation was 45 mm. Mean patient age was 67 ± 17 years, and 79% of patients (26 of 33) were women. During the period in question, we used four approaches: Treatment with acetabular component revision in 18 of 33 patients (55%), head and liner exchange in nine patients (27%), both-component revision in five patients (15%), and isolated femoral component revision in one patient (3%). A constrained liner was used in 17 patients (52%), including six of the patients treated with acetabular component revision, and three of those who had both-component revisions. During the period in question, our general indications were hip pain and/or unacceptable function with the chronically dislocated prosthesis. Our sample size was too small to evaluate the association of the procedure choice on survivorship or complication risk. We used Kaplan-Meier survivorship analysis to estimate survivorship free from complication, reoperation, or revision. Mean followup was 4.4 years (range, 2-10 years). Survivorship free from any revision, complication, or reoperation was 61% at 5 years (95% CI, 43-82). Survivorship free from revision was 83% at 5 years (95% CI, 67-98). Etiology for revision was aseptic loosening in three of 33 hips (9%), recurrent dislocation in two hips (6%), and deep periprosthetic joint infection in two hips (6%). Five complications (15%) did not result in a reoperation, including one dislocation and one incomplete peroneal nerve palsy in a patient after an anterolateral approach. The Harris hip score improved from mean 50 ± 17 preoperatively to mean 80 ± 11 at 5 years. Chronically dislocated THAs can be successfully managed with revision THA. We recommend close evaluation of the components for aseptic loosening, performing revision surgery only on patients with pain and poor function, and thoroughly counseling patients that survivorship is modest and complications are common. Level IV, therapeutic study.

Preliminary results of a 3D-printed acetabular component in the management of extensive defects.

The treatment of extensive bone loss and massive acetabular defects can be compounded by several challenges and pitfalls. The survivorship following acetabular revision with extensive bone loss is still unsatisfactory. The goal of the present study was to analyse the outcomes of 3D-printed patient-specific acetabular components in the management of extensive acetabular defects and combined pelvic discontinuity (PD). 9 patients underwent revision THA using 3D-printed custom acetabular components to reconstruct extensive acetabular defects. The Paprosky classifications were determined in all patients. The primary outcome measure was the implant-associated failure rate. 1 out of 9 patients suffered an implant-associated complication (11%). The overall implant-associated survival rate was 89%. The overall complication rate was 56%. The patient-specific acetabular component technique shows promise for the treatment of patients with severe acetabular defects in revision THA. Further research aimed at reducing costs and improving the complication rate are warranted.

CORR Insights(®): High Survivorship With Cementless Stems and Cortical Strut Allografts for Large Femoral Bone Defects in Revision THA.

Where Are We Now? Femoral bone loss is frequently encountered during revision THA. The key is determining the quality and quantity of bone loss, as well as quality and quantity of remaining host bone. In contemporary North American practices, diaphyseal fixation with either an extensively porous-coated stem or titanium modular fluted tapered (TMFT) stem is the standard of care for the majority of hips with bone defects rated Paprosky Type IIIB or less. The basic principle in both techniques is the importance of obtaining immediate axial and rotational stability. The two main clinical concerns with extensively porous-coated stems are intraoperative periprosthetic femoral fracture and stress shielding over time. In response to these concerns, the interest in TMFT stems is increasing, and the indications for their use seem to be expanding [1]. The real controversy is in those patients with Paprosky Type IV defects in whom rotational stability in the diaphysis would not be possible to obtain. In this difficult setting, consideration has traditionally been given to allograft-prosthetic composites (APCs), impaction bone grafting with long cemented stems, proximal femoral replacements, and more recently, TMFT stems. In this intriguing paper by Kim et al., the authors studied 130 patients (140 hips) with Paprosky Type IIIB (54%) and Type IV (46%) defects who underwent revision THA. Even though all patients had less than 2 cm of available isthmic bone, the surgeons used extensively porous-coated stems. However, cortical strut allografts (one strut in 10%, two struts in 75%, and three struts in 15%) were used to provide primary stability for the extensively porous-coated stems. At a mean followup of 16 years, the authors found that all allografts had incorporated, and 87% of stems had radiographic evidence of bony ingrowth. Where Do We Need To Go? When massive bone loss is encountered during revision THA, structural allografts are often a helpful technique. However, followup radiographic analysis of strut incorporation is complicated, and alternative approaches are required to see if these devices are indeed well-fixed. Moreover, deep periprosthetic infection in revision surgery remains a paramount concern to patients and surgeons alike. This may influence the liberal use of struts, particularly in those patients undergo reimplantation THA. Finally, additional investigations comparing the results of patients with prior cemented and uncemented stems are needed given that the remaining host bone quality is starkly different. How Do We Get There? Given the complicated nature of radiographically analyzing strut incorporation, retrieval studies investigating the interface between the cortical strut allograft and an extensively porous-coated stem, as well correlation with radiographic findings, will be helpful in determining where bony ingrowth occurs (if at all). In addition, with infection being one of the most common reasons for femoral component revision, the results of the proposed technique by Kim et al. in septic cases must be studied. Finally, a comprehensive and large-scale analysis of contemporary stems, such as the TMFT stem, will be essential to determine if outcomes vary based upon prerevision diagnosis, particularly between failed cemented and uncemented stems. This will likely require either a multicenter investigation, or large national registries such as the American Joint Replacement Registry, to complete. I suspect that as the body of evidence continues to grow on TMFT stems in Paprosky Type IV defects, their popularity will continue given their larger diameters, as well as the ability to adjust leg length, offset, and version independent of diaphyseal fixation.

The Fate of Grafting Acetabular Defects During Revision Total Hip Arthroplasty

Acetabular defects are frequently grafted during revision THA. Previous studies using plain radiographs report high rates of graft incorporation. However, given plain radiographs underestimate osteolysis, it is unclear whether plain radiographs adequately reflect graft fill or incorporation. We determined if (1) graft fill; or (2) incorporation (measured as graft-bone contact) differed with complete revision and grafting compared to liner exchange and grafting; (3) defect fill and incorporation could be assessed on plain radiographs; and (4) the cost of bone grafting differed with these two procedures. We identified 40 patients who underwent revision THA for aseptic loosening or polyethylene wear and osteolysis, either with retention of a well-fixed cup or complete acetabular revision in which bone graft was used. Lesion size, percent fill, and graft healing was quantified from CT scans. A limited cost analysis was performed using the current hospital costs for implants, bone grafts, and bone graft substitutes. The minimum followup was 1 year (mean, 4.8 years; range, 1-11 years). The average defect fill was 30% (range, 0%-81%). The average percent of healing to host bone was 24% (range, 0-66%). Complete revisions had a higher percent defect fill compared to head/liner changes (47% versus 17%) as well as a higher degree of graft healing to host bone compared to head/liner changes (36% versus 14%). High resolution CT demonstrated lower percentages of defect fill and graft healing than previous reports based on plain radiographs. Bone grafting costs exceeded implant costs in the head/liner exchange group; however, the overall cost was higher in the complete revision group. Higher degrees of defect fill and healing were seen with complete revisions compared to head/liner exchanges. Compared to CT scans, plain radiograph assessment tended to overestimate defect fill and healing.

Tranexamic Acid Reduces Allogenic Transfusion in Revision Hip Arthroplasty

Revision THA is associated with high blood loss and a high probability of blood transfusion in the perioperative period. In November 2003, government legislation established the Blood Utilization Program at our center to reduce the rate and risks associated with allogenic transfusion. The purposes of this study were to (1) determine whether the allogenic transfusion rate in patients undergoing revision THA decreased in those who were reviewed preoperatively by the Blood Utilization Program versus those who were not; (2) determine whether tranexamic acid reduced the rate of transfusion; and (3) identify potential perioperative clinical parameters that are associated with an increased risk of blood transfusion. We included all 159 patients who underwent revision THA from January 2006 to October 2008 having either a socket and/or femoral stem revision except those having only a liner exchange. One hundred and one patients attended the Blood Utilization Program preoperatively and 58 patients did not (ie, they required urgent/emergency surgery). The Blood Utilization Program referral made no difference in transfusion rate or transfusion amount; however, the transfusion rates and amount were decreased by 8% and one unit, respectively. In patients referred to the Blood Utilization Program, the intraoperative use of tranexamic acid (an antifibrinolytic) was associated with reduced transfusions, regardless of dosage; preoperative erythropoietin tended to reduce transfusions while preoperative oral iron supplements did not. To further increase the relevance of the blood utilization program, the guidelines for patients undergoing revision hip arthroplasty need to be redefined. Level III, therapeutic study. See the guidelines online for a complete description of level of evidence.

当科における人工股関節再置換術の短期成績〜ステム側の評価を中心に〜

The purpose of present study was to evaluate the short-term results of revision total hip arthroplasty (revision THA) without cement. Thirty-two hips of 31 patients who underwent revision THA from September 1998 to June 2003 were enrolled. There were 6 men 7 hips and 25 female 25 hips, and the mean age at revision THA was 65.7 years. According to Endo-Klinik classification, four hips were grade 1, seventeen hips were grade 2, nine hips were grade 3, one hip was grade 4, and there was one fracture. The average full weight bearing time was nine days after operation. There was only one hip, which showed 3 mm subsidence of the stem. When initial fixation was obtained, early full weight bearing and early social rehabilitation were possible.

当科における人工股関節再置換術の短期成績

The purpose of present study is to report the short-term results of revision total hip arthroplasty (revision THA) without cement. Thirty-four hips of 33 patients who underwent revision THA from September 1998 to August 2002 and who could be followed up for one year or more were enrolled in the study. There were six men seven hips and 27 female 27 hips, and mean age was 73 years. In AAOS classification, Type 2 was eight hips and Type 3 was 26 hips. The average full weight bearing time was 8 days. Only one hip was movement of acetabular component and required re-operation. Initial fixation in acetabular enabled early full weight bearing and early social rehabilitation.