High Mortality After Total Knee Arthroplasty Periprosthetic Joint Infection is Related to Preoperative Morbidity and the Disease Process but Not Treatment

BackgroundPeriprosthetic joint infection (PJI) mortality rate is approximately 20%. The etiology for high mortality remains unknown. The objective of this study was to determine whether mortality was associated with preoperative morbidity (frailty), sequalae of treatment, or the PJI disease process itself.MethodsA multicenter observational study was completed comparing 184 patients treated with septic revision total knee arthroplasty (TKA) to a control group of 38 patients treated with aseptic revision TKA. Primary outcomes included time and the cause of death. Secondary outcomes included preoperative comorbidities and Charlson Comorbidity Index (CCMI) measured preoperatively and at various postoperative timepoints.ResultsThe septic revision TKA cohort experienced earlier mortality compared to the aseptic cohort, with a higher mortality rate at 90 days, 1, 2, and 3 years after index revision surgery (P = .01). There was no significant difference for any single cause of death (P > .05 for each). The mean preoperative CCMI was higher (P = .005) in the septic revision TKA cohort. Both septic and aseptic cohorts experienced a significant increase in CCMI from the preoperative to 3 years postoperative (P < .0001 and P = .002) and time of death (P < .0001 both) timepoints. The septic revision TKA cohort had a higher CCMI 3 years postoperatively (P = .001) and at time of death (P = .046), but not one year postoperatively (P = .119).ConclusionCompared to mortality from aseptic revision surgery, septic revision TKA is associated with earlier mortality, but there is no single specific etiology. As quantified by changes in CCMI, PJI mortality was associated with both frailty and the PJI disease process, but not treatment.     

Midterm Results of Hybrid Cement Technique in Revision Total Knee Arthroplasty

While the number of revision total knee arthoplasties (TKA) performed in the United States continues to rise annually, controversy exists whether intramedullary stems should be cemented or press-fit. Retrospective analysis of midterm survivorship rate of revision TKA using hybrid stem fixation in 119 patients was performed. Revision was performed predominantly for aseptic loosening (78) and infections (28). Average follow-up was 62 months (range, 46–80). Knee Society Pain and Function scores improved from 39 and 58 to 68 and 79 (P < .05). Fifty-eight tibial offsets and 28 femoral offsets were utilized. Three knees (2.5%) required revision without any cases of aseptic loosening. Radiographic complete or progressively advanced (> 2 mm) radiolucent lines were not observed in any patient. At mid-term follow-up, revision hybrid TKA provides excellent fixation with extremely low rates of aseptic loosening and avoids the inherent complications of extensive intramedullary cement.     

Revision Total Joint Arthroplasty: The Epidemiology of 63,140 Cases in New York State

Recent evidence suggests a substantial rise in the number of revision total joint arthroplasty (TJA) procedures performed. The New York State SPARCS inpatient database was utilized to identify revision total shoulder, knee, and hip arthroplasty procedures between 1993 and 2010. Yearly incidence and related epidemiology were analyzed. A total of 1,806 revision TSA, 26,080 revision TKA, and 35,254 revision THA cases were identified. The population-based incidence of these procedures increased 288%, 246%, and 44% respectively (P < 0.001). Revision burden for hip arthroplasty decreased from 16.1% in 2001 to 11.5% in 2010 (P < 0.001). The rates of revision TSAs and TKAs increased at a substantially faster rate than that of revision THAs. Revision burden for hip arthroplasty steadily has decreased since 2001.     

Risk of Prosthetic Joint Infection Increases Following Early Aseptic Revision Surgery of Total Hip and Knee Arthroplasty

BackgroundIt is important to identify risk factors for periprosthetic joint infection (PJI) following total joint arthroplasty in order to mitigate the substantial social and economic burden. The objective of this study is to evaluate early aseptic revision surgery as a potential risk factor for PJI following total hip (THA) and total knee arthroplasty (TKA).MethodsPatients who underwent primary THA or TKA with early aseptic revision were identified in 2 national insurance databases. Control groups of patients who did not undergo revision were identified and matched 10:1 to study patients. Rates of PJI at 1 and 2 years postoperatively following revision surgery were calculated and compared to controls using a logistic regression analysis.ResultsIn total, 328 Medicare and 222 Humana patients undergoing aseptic revision THA within 1 year of index THA were found to have significantly increased risk of PJI at 1 year (5.49% vs 0.91%, odds ratio [OR] 5.61, P < .001 for Medicare; 7.21% vs 0.68%, OR 11.34, P < .001 for Humana) and 2 years (5.79% vs 1.10%, OR 4.79, P < .001 for Medicare; 8.11% vs 1.04%, OR 9.05, P < .001 for Humana). Similarly for TKA, 190 Medicare and 226 Humana patients who underwent aseptic revision TKA within 1 year were found to have significantly higher rates of PJI at 1 year (6.48% vs 1.16%, OR 7.69, P < .001 for Medicare; 6.19% vs 1.28%, OR 4.89, P < .001 for Humana) and 2 years (8.42% vs 1.58%, OR 6.57, P < .001 for Medicare; 7.08% vs 1.50%, OR 4.50, P < .001 for Humana).ConclusionEarly aseptic revision surgery following THA and TKA is associated with significantly increased risks of subsequent PJI within 2 years.     

Major Shortening of the Patellar Tendon During Septic Two-Stage Knee Arthroplasty Revision Using Static Spacers

BackgroundTwo-stage septic revision knee arthroplasty (TKA) often results in inferior functional outcome after reimplantation, which might be due to impairments of the extensor mechanism. The aim of the current study was to elucidate possible alterations in extensor mechanisms during septic two-stage revision of TKA treated with a static spacer.MethodsThis retrospective study included 87 patients (42 women, 45 men, age 64.5 ± 10.5; range, 29-85 years) undergoing septic two-stage TKA revision using a static spacer. The modified Insall Salvati ratio (mISR) was calculated via calibrated true lateral radiographs by two independent orthopedic surgeons before TKA explantation (G0), 6-8 days after TKA removal (G1), one day before TKA reimplantation (G2) and 6-8 days after TKA reimplantation (G3). Age, sex, body mass index (BMI), index C-reactive protein level, and number of previous surgeries were evaluated to identify the possible correlations.ResultsOverall, mISR significantly decreased within the first 6 days after index surgery from 1.71 ± 0.41 to 1.63 ± 0.41 (G0 versus G1, P < .001) and showed a further decline within the next 6 weeks to 1.54 ± 0.39 (G1 versus G2, P = .002). Conversely, mISR increased after reimplantation of TKA to 1.6 ± 0.43 (G3 versus G2, P = .08), though it did not regain preoperative baseline levels (G0 versus G3, P < .001). The subgroup with mISR decrease ≥10% experienced patellar tendon shortening of 16% between G0 and G1, 19% between G0 and G2 and up to 20% between G0 and G3. There were weak correlations concerning age (r = ?0.240, P = .038), preoperative C-reactive protein level (r = 0.239, P = .04) and patellar tendon shortening. Intraclass correlation coefficient (ICC)was 0.88 concerning radiographic measurement.ConclusionSeptic two-stage TKA revision using static spacers leads to irreversible alterations of the extensor mechanism, specifically a major shortening of the patellar tendon, in one out of 3 patients.Level of evidenceII.     

10-Year Cumulative Incidence and Indications for Revision Total Knee Arthroplasty Among Patients Who Have Sickle Cell Disease

BackgroundLiterature regarding total knee arthroplasty (TKA) outcomes in sickle cell disease (SCD) is limited. Moreover, 10-year survivorship of SCD implants is unknown. This study aimed to observe 10-year cumulative incidence and indications for revision TKA in patients who did and did not have SCD.MethodsPatients who underwent primary TKA were identified using a large national database. The SCD patients were matched by age, sex, and a comorbidity index to a control cohort in a 1:4 ratio. The 10-year cumulative incidence rates were determined using Kaplan–Meier survival analyses. Multivariable analyses were conducted using Cox proportional hazard modeling. Chi-squared analyses were conducted to compare indications for revision between cohorts. In total, 1,010 SCD patients were identified, 100,000 patients included in the unmatched control, and 4,020 patients included in the matched control.ResultsCompared to the unmatched control cohort, SCD patients exhibited higher 10-year all-cause revision (HR: 1.86; P < .001) with higher proportions of revisions for periprosthetic joint infection (PJI) (P < .001), aseptic loosening (P < .001), and hematoma (P < .001). Compared to the matched control, SCD patients had higher 10-year all-cause revision (Hazard Ratio (HR): 1.39; P = .034) with a higher proportion of revisions for PJI (P = .044), aseptic loosening (P = .003), and hematoma (P = .019).ConclusionIndependent of other comorbidities, SCD patients are more likely to undergo revisions for PJI, aseptic loosening, and hematoma compared to patients who do not have SCD. Due to the high-risk of these complications, perioperative and postoperative surgical optimization should be enforced in SCD patients.     

Single-Stage Revision of the Infected Total Knee Arthroplasty Is Associated With Improved Functional Outcomes: A Propensity Score–Matched Cohort Study

BackgroundSingle-stage revision is an alternative to the standard 2-stage revision, potentially minimizing morbidities and improving functional outcomes. This study aimed at comparing single-stage and 2-stage revision total knee arthroplasty (TKA) for chronic periprosthetic joint infection (PJI) with regard to patient-reported outcome measures (PROMs) and complication rates.Methods:A total of 185 consecutive revision TKA patients for chronic PJI with complete preoperative and postoperative PROMs were investigated. A total of 44 patients with single-stage revision TKA were matched to 88 patients following 2-stage revision TKA using propensity score matching, yielding a total of 132 propensity score–matched patients for analysis. Patient demographics and clinical information including reinfection and readmission rates were evaluated.Results:There was no significant difference in preoperative PROMs between propensity score–matched single-stage and 2-stage revision TKA cohorts. Postoperatively, significantly higher PROMs for single-stage revision TKA were observed for Knee disability and Osteoarthritis Outcome Score physical function (62.2 vs 51.9, P < .01), physical function short form 10A (42.8 vs 38.1, P < .01), PROMIS SF Physical (44.8 vs 41.0, P = .01), and PROMIS SF Mental (50.5 vs 47.1, P = .02). There was no difference between propensity score–matched single-stage and 2-stage revision TKA cohorts for clinical outcomes including reinfection rates (25.0% vs 27.2%, P = .78) and 90-day readmission rates (22.7% vs 25.0%, P = .77).ConclusionThis study illustrated that single-stage revision TKA for chronic PJI may be associated with superior patient-reported outcomes compared to 2-stage revision for the infected TKA using a variety of PROMs. Improved PROMs were not accompanied by differences in complication rates between both cohorts, suggesting that single-stage revision TKA may provide an effective alternative to 2-stage revision in patients with chronic TKA PJI.     

Unexpected Positive Cultures in Patients Who Have a History of Septic Revision in the Same Joint

BackgroundThe prevalence of unexpected positive cultures (UPC) in an aseptic revision surgery of the joint with a prior septic revision in the same joint remains unknown. The purpose of this study was to determine the prevalence of UPC in that specific group. As secondary outcomes, we explored risk factors for UPC.MethodsThis retrospective study includes patients who had an aseptic revision total hip/knee arthroplasty procedure with a prior septic revision in the same joint. Patients who had less than 3 microbiology samples, without joint aspiration or with aseptic revision surgery performed <3 weeks after a septic revision were excluded. The UPC was defined as a single positive culture in a revision that the surgeon had classified as aseptic according to the 2018 International Consensus Meeting. After excluding 47, a total of 92 patients were analyzed, who had a mean age of 70 years (range, 38 to 87). There were 66 (71.7%) hips and 26 (28.3%) knees. The mean time between revisions was 83 months (range, 31 to 212).ResultsWe identified 11 (12%) UPC and in 3 cases there was a concordance of the bacteria compared to the previous septic surgery. There were no differences for UPC between hips/knees (P = .282), diabetes (P = .701), immunosuppression (P = .252), previous 1-stage or 2-stages (P = .316), causes for the aseptic revision (P = .429) and time after the septic revision (P = .773).ConclusionThe prevalence of UPC in this specific group was similar to those reported in the literature for aseptic revisions. More studies are needed to better interpret the results.     

Patient-Reported Outcomes and Satisfaction 1 to 3 Years After Revisions of Total Knee Arthroplasties for Unexplained Pain Versus Aseptic Loosening

BackgroundIt is unknown if patients are relieved of pain after knee arthroplasty revision for unexplained pain. The aim of this cross-sectional case-control study was to compare patient-reported outcome measures (PROMs) and satisfaction 1 to 3 years after revision of total knee arthroplasties (TKAs) for the indications of unexplained pain versus aseptic loosening.MethodsWe included 384 patients undergoing TKA revision for the indications of unexplained pain and aseptic loosening from January 1, 2018 to December 31, 2020 from the Danish Knee Arthroplasty Register. A total of 81 patients were revised for unexplained pain and 303 for aseptic loosening. Questionnaires including PROMs (Oxford Knee Score, EQ-5D-5L, and Forgotten Joint Score) and satisfaction with the surgery on a 0-100 scale (100 = not satisfied; 0 = very satisfied) were sent to digitally secured mailboxes. Time from revision to data collection was a median 3.1 years (range, 1.4-4.4 years).ResultsMedian Oxford Knee Score was 25 (interquartile range [IQR] 15) versus 31 (IQR 18) 1-3 years after revisions for unexplained pain versus aseptic loosening, P = .009. Median EQ-5D-5L was 0.6 (IQR 0.4) versus 0.8 (IQR 0.3) for unexplained pain versus aseptic loosening, P = .009. Median Forgotten Joint Score was 50 (IQR 7) versus 50 (IQR 16) for unexplained pain versus aseptic loosening, P = .905. Satisfaction was 75 (IQR 38) for unexplained pain and 50 (IQR 73) for aseptic loosening, P < .001.ConclusionPatients undergoing TKA revision for the indication of unexplained pain had worse results on PROMs than those revised for aseptic loosening. Likewise, patients revised for unexplained pain were less satisfied compared to patients revised for aseptic loosening. This information is valuable to both surgeons and patients when candidates for revision surgery are selected, to obtain the best possible outcomes.     

Use of Stepped Porous Titanium Metaphyseal Sleeves for Tibial Defects in Revision Total Knee Arthroplasty: Short Term Results

Stepped porous titanium metaphyseal sleeves may provide an option for enhanced fixation in managing challenging tibial defects in revision total knee arthroplasty (TKA). We retrospectively reviewed data on 51 patients who underwent revision TKA utilizing a metaphyseal sleeve for Anderson Orthopaedic Research Institute (AORI) Type II and III tibial defects between June 2007 and July 2011. Of these 51 patients, 36 patients had complete clinical and radiographic data. At final follow-up (mean: 38 months) significant improvements in knee range of motion and Knee Society scores were observed postoperatively (P < 0.001). Four revision procedures were necessary, but none for aseptic implant fixation failure. Radiographic review at final follow-up revealed stable, osteointegrated components without component migration or clinically significant osteolysis. Metaphyseal sleeve use in the management of moderate to severe tibial defects in revision TKA resulted in satisfactory clinical outcomes and is a versatile option for achieving stable fixation.     

Revision Knee Arthroplasty for Bone Loss: Choosing the Right Degree of Constraint

Revision total knee arthroplasty (TKA) in the setting of bone deficiency requires varied levels of constraint to restore knee stability. However, the outcomes between different levels remain controversial. Clinical outcomes for 183 AORI Type I knees, 168 Type II knees and 124 Type III knees utilizing posterior stabilized (PS), unlinked constrained (UC) or hinged prostheses were evaluated with standardized clinical assessment tools and radiographic results over an average of 7.4 years. PS yielded superior knee scores in AORI Type I patients (P < 0.05), UC in Type II and III aseptic patients (P < 0.05), and a hinge was preferred in septic Type II or III knees (P < 0.05). Revision TKA conducted with increased constraint appears effective in the setting of increased bone deficiency.     

Incidence of and Risk Factors for 30-Day Readmission Following Elective Primary Total Joint Arthroplasty: Analysis From the ACS-NSQIP

Recently, the government has moved towards public reporting of 30-day readmission rates after elective primary total knee (TKA) and total hip arthroplasty (THA). We identified 11,814 and 8105 patients who underwent primary TKA and THA from the 2011 ACS NSQIP. Overall readmission rates within 30-days of surgery were 4.6% for TKA and 4.2% for THA. Complications associated with readmission were predominantly wound infections, sepsis, thromboembolic, cardiac, and respiratory related. In TKA, multivariate analysis identified age (P = 0.002), male gender (P = 0.03), cancer history (P = 0.008), elevated BUN (P = 0.002), a bleeding disorder (P < 0.001) and high ASA class (P < 0.001) as predictors of readmission. In THA, obesity (P = 0.008), steroid use (P = 0.037), a bleeding disorder (P = 0.002), dependent functional status (P = 0.022), and high ASA class (P < 0.001) predicted readmission. Understanding characteristics associated with readmission will be essential for equitable patient risk stratification.     

Increased Revisions in Conversion Total Knee Arthroplasty After Periarticular Open Reduction Internal Fixation Compared With Primary Total Knee Arthroplasty: A Matched Cohort Analysis

BackgroundPrior studies on conversion total knee arthroplasty (cTKA) have reported increased technical challenges and risk of complications compared with primary knee arthroplasty. The purpose of this study was to compare two-year postoperative complication/revision rates between patients undergoing cTKA after prior periarticular open reduction and internal fixation (ORIF) and those undergoing primary TKA.MethodsPatients who underwent cTKA after prior periarticular ORIF of the ipsilateral knee were identified in a national all-payer claims database from 2010 to 2018. This ORIF-cTKA cohort was propensity matched to participants undergoing primary TKA based on age, gender, Charlson comorbidity index, and obesity status. Univariate analysis was performed to analyze differences in two-year complication and revision rates.ResultsAfter propensity matching, 823 patients were included in the ORIF-cTKA cohort and 1640 patients in the primary TKA cohort. No differences in demographics or comorbidities existed between cohorts. Relative to the primary TKA cohort, the ORIF-cTKA cohort had significantly higher incidences of all-cause revision (5.47% vs 2.47%, P = .001), periprosthetic joint infection (PJI; 4.74% vs 1.34%, P < .001), and intraoperative or postoperative periprosthetic fracture (1.58% vs 0.55%, P = .01) at two years postoperatively. There was also a nonsignificant trend toward increased rates of aseptic loosening (1.82% vs 0.91%, P = .052) in the ORIF-cTKA.ConclusionRelative to primary TKA, cTKA after periarticular ORIF is associated with significantly increased rates of all-cause revision, PJI, and periprosthetic fracture at two years postoperatively. Surgeons should counsel these patients about the increased risks of these postoperative complications and consider treating them as high risk for PJI in the perioperative period.     

Migration Patterns for Revision Total Knee Arthroplasty in the United States as Reported in the American Joint Replacement Registry

BackgroundRevision total knee arthroplasty (TKA) is associated with a higher complication rate and a greater cost when compared to primary TKA. Based on patient choice, referral, or patient transfers, revision TKAs are often performed in different institutions by different surgeons than the primary TKA. The aim of this study is to evaluate the effect of hospital size, teaching status, and revision indication on the migration patterns of failed primary TKA in patients 65 years of age and older.MethodsAll primary and revision TKAs reported to the American Joint Replacement Registry from January 2012 through March 2020 were included and merged with the Centers for Medicare and Medicaid Services database. Migration was defined as a patient having a primary TKA and revision TKA performed at separate institutions by different surgeons.ResultsIn total, 9167 linked primary and revision TKAs were included in the analysis. Overall migration rates were significantly higher from small (<100 beds; P = .019), non-teaching institutions (P = .002) driven primarily by patients diagnosed with infection. Infection patients had significantly higher migration rates from small (46.8%, P < .001), non-teaching (43.5%, P < .001) institutions, while migration rates for other causes of revision were statistically similar. Most patients migrated to medium or large institutions (84.7%) for revision TKA rather than small institutions (15.3%, P < .001) and to teaching (78.3%) rather than non-teaching institutions (21.7%, P < .001).ConclusionThere is a diagnosis-dependent referral bias that affects the migration rates of infected primary TKA from small non-teaching institutions leading to a flow of more medically complex patients to medium and large teaching institutions for infected revision TKA.     

The Impact of Epilepsy on Complication Rates After Total Joint Arthroplasty: A Propensity Score–Matched Cohort Study

BackgroundIt is unclear how epilepsy may affect total joint arthroplasty outcomes. The purpose of this study is to analyze the impact of epilepsy on prosthesis-related complications following primary total hip arthroplasty (THA) and total knee arthroplasty (TKA).MethodsA retrospective cohort study was conducted using a national database. Patients who have epilepsy underwent a primary THA (n = 6,981) and TKA (n = 4,987) and were matched 1:4 (THA, n = 27,924; TKA, n = 19,948). Rates of low-energy falls and prosthesis-related complications within 2 years postoperatively were compared for patients who did and did not have epilepsy with multivariable logistic regression.ResultsAfter primary TKA, patients who have epilepsy exhibited significantly higher rates of aseptic revision (4.3% versus 3.5%, odds ratio [OR] 1.21, P = .017) and revision for prosthetic joint infection (1.8% versus 1.3%, OR 1.29, P = .041). THA patients who have epilepsy exhibited significantly higher rates of prosthetic dislocation (3.2% versus 1.9%, OR 1.54, P < .001), periprosthetic fracture (2.2% versus 0.8%, OR 2.39, P < .001), and aseptic loosening (1.7% versus 1.1%, OR 1.40, P = .002). Rates of low-energy falls within 2 years after TKA (14.1% versus 6.4%, OR 2.19, P < .001) and THA (33.6% versus 7.5%, OR 5.95, P < .001) were also significantly higher for patients who have epilepsy.ConclusionEpilepsy was associated with significantly higher rates of falls (P < .001) and prosthesis-related complications after primary THA (P < .05) and TKA (P < .05). Precautions should be implemented in this population during intraoperative and perioperative decision-making to reduce complication risk.Level of EvidenceLevel III.     

Prior Knee Arthroscopy Is Associated With Increased Risk of Revision After Total Knee Arthroplasty

BackgroundKnee arthroscopy (KA) is frequently performed to provide improved joint function and pain relief. However, outcomes following total knee arthroplasty (TKA) after prior KA are not fully understood. The purpose of this study is to determine the relationship between prior KA within 2 years of TKA on revision rates after TKA.MethodsData were collected from the Humana insurance database using the PearlDiver Patient Records Database from 2006 to 2017. Subjects were identified using Current Procedural Terminology and International Classification of Diseases procedure codes to identify primary TKA. Patients were stratified into 2 groups based upon a history of prior KA. Univariate and multivariate analyses were conducted to determine association between KA and outcomes at 2-year postoperative period.ResultsIn total, 138,019 patients were included in this study, with 3357 (2.4%) patients receiving a KA before TKA and 134,662 (97.6%) patients who did not. The most common reason for KA was osteoarthritis (40.0%), followed by medial tear of the meniscus (26.0%) and chondromalacia (21%.0). After adjustment, prior KA was associated with increased revision rate (odds ratio [OR], 1.392; P = .003), postoperative stiffness (OR, 1.251; P = .012), periprosthetic joint infection (OR, 1.326; P < .001), and aseptic loosening (OR, 1.401; P = .048).ConclusionPrior KA is significantly associated with increased 2-year TKA revision rate. The most common etiology for arthroscopy was osteoarthritis. The results of the study, showing that arthroscopy before TKA substantially increases the rates of revision, PJI, aseptic loosening, and stiffness, lend further credence to the idea that patients may be better served by nonsurgical management of their degenerative pathology until they become candidates for TKA. Subjecting this population to arthroscopy appears to offer limited benefit at the cost of poorer outcomes when they require arthroplasty in the future.Level of EvidenceLevel III therapeutic study.     

Septic Revision Total Knee Arthroplasty Is Associated With Significantly Higher Mortality Than Aseptic Revisions: Long-Term Single-Center Study (1254 Patients)

BackgroundThe aim of this study is to examine the differences in long-term mortality rates between septic and aseptic revision total knee arthroplasty (rTKA) in a single specialist center over 17-year period.MethodsRetrospective consecutive study of all patients who underwent rTKA at our tertiary center between 2003 and 2019 was carried out. Revisions were classified as septic or aseptic. We identified patients’ age, gender, American Society of Anesthesiologists grade, and body mass index. The primary outcome measure was all-cause mortality at 5 years, 10 years, and over the whole study period of 17 years. Death was identified through both local hospital electronic databases and linked data from the National Joint Registry/NHS Personal Demographic Service. Kaplan-Meier survival curves were used to estimate time to death.ResultsIn total, 1298 consecutive knee revisions were performed on 1254 patients (44 bilateral revisions) with 985 aseptic revisions in 945 patients (75.4%) and 313 septic revisions in 309 patients (24.6%). Average age was 70.6 years (range 27-95) with 720 females (57.4%). Septic revisions had higher mortality rates; patients’ survivorship for septic vs aseptic revisions was 77.6% vs 89.5% at 5 years, 68.7% vs 80.2% at 10 years, and 66.1% vs 75.0% at 17 years; these differences were all statistically significant (P < .0001). The unadjusted 10-year risk ratio of death after septic revision was 1.59 (95% confidence interval 1.29-1.96) compared to aseptic revisions.ConclusionrTKA performed for infection is associated with significantly higher long-term mortality at all time points compared with aseptic revision surgery.Level of EvidenceLevel IV.     

Infection Is Not a Risk Factor for Perioperative and Postoperative Blood Loss and Transfusion in Revision Total Hip Arthroplasty

Background

Septic hip revisions are associated with greater complications and higher costs than aseptic revisions. It is unclear whether blood loss and transfusion requirements are different in septic and aseptic revisions. We hypothesized that the blood loss and transfusion are dependent on the complexity of the revision surgery and patient's general health rather than the presence of infection.

Weight Gain After Primary Total Knee Arthroplasty Is Associated With Accelerated Time to Revision for Aseptic Loosening

BackgroundObesity is a major health problem worldwide and is associated with complications after total knee arthroplasty (TKA). It remains unknown whether a change in body mass index (BMI) after primary TKA affects the reasons for revision TKA or the time to revision TKA.MethodsA total of 160 primary TKAs referred to an academic tertiary center for revision TKA were retrospectively stratified according to change in BMI from the time of their primary TKA to revision TKA. The association between change in BMI and time to revision was also analyzed according to indication for revision of TKA using Pearson's chi-square test.ResultsThe mean change in BMI from primary to revision TKA was 0.82 ± 3.5 kg/m². Maintaining a stable weight after primary TKA was protective against late revision TKA for any reason (P = .004). Patients who failed to reduce their BMI were revised for aseptic loosening earlier, at less than 5 years (P = .020), whereas those who reduced their BMI were revised later, at over 10 years (P = .004).ConclusionMaintaining weight after primary TKA is protective against later revision TKA for any reason but failure to reduce weight after primary TKA is a risk factor for early revision TKA for aseptic loosening and osteolysis. Orthopedic surgeons should recommend against weight gain after primary TKA to reduce the risk of an earlier revision TKA in the event that a revision TKA is indicated.     

Utility and Prognostic Ability of a Diagnostic Injection Before Revision Total Knee Arthroplasty

BackgroundDiagnostic injections are commonly utilized in the workup of painful total knee arthroplasties (TKA), particularly when the diagnosis remains unclear. However, current literature provides limited evidence regarding the utility and prognostic capability of anesthetic injections in this scenario. This study sought to establish the role of diagnostic injections in predicting successful revision TKA.MethodsA retrospective review was conducted on 144 consecutive aseptic revision TKAs receiving diagnostic anesthetic injections. Instability (57.6%) and aseptic loosening (33.3%) comprised most revision etiologies. Patient-reported percentage pain relief after the injection was statistically correlated with KOOS JR, Knee Society Score, UCLA Activity Level, and satisfaction scores.ResultsAbout 74.3% (107/144) of revision TKAs reported >50% pain relief after injection. There were no differences in pain relief based on revision indication (P = .841). Improvement from preoperative activity level was greater in the >50% pain relief group (P = .024). Four-month patient satisfaction did not differ between patients who reported >50% and ≤50% pain relief (67% vs. 66%, P = .130). About 64% of patients who reported >50% pain relief were satisfied at minimum 1-year follow-up, compared with only 47% of those who reported ≤50% pain relief after diagnostic injection (P < .001).ConclusionStudy results show that patients reporting >50% pain relief after diagnostic injection have improvements in activity level and maintain greater satisfaction at minimum 1-year than those reporting ≤50% pain relief. Expectations for improvement after revision TKA should be tempered if diagnostic anesthetic injection yields minimal subjective pain relief.