What Is the True Impact of Periprosthetic Joint Infection Diagnosis on Mortality?

BACKGROUND: Mortality is a quality indicator that may affect expenditures. Revisions for periprosthetic joint infection (PJI) are, on average, more expensive and exhibit higher morbidity than aseptic revisions, although reimbursement is similar. Therefore, we sought to determine (1) impact on mortality rates of revision total hip and/or knee arthroplasty performed for PJI diagnosis (septic) versus aseptic revisions, at any point in time, and (2) mortality predictors among PJI patients. METHODS: Retrospective chart review of 978 consecutive patients who underwent revision at a single institution (January 2015 to November 2020). All revisions were evaluated, and it was determined whether patients had a revision for PJI at any point in time or not. Two groups were compared: (1) patients with septic revision(s) (n = 350) and (2) patients who only underwent aseptic revision(s) (n = 628). Demographics and mortality status at latest follow-up (mean 3 years, range: 0 to 18 years, from first revision ever) were assessed. Mortality status was also separately assessed among patients who exclusively had hip revision(s), or solely knee revision(s), or both. Multivariate regression analysis (Cox) was used to determine whether PJI diagnosis was an independent mortality predictor. Among PJI patients, potential mortality predictors were evaluated. RESULTS: Overall, 65 patients died (6.6%). The septic cohort had significantly more men and American Society of Anesthesiologists (ASA) class-IV patients. Mortality rates were 10.9% and 4.3% (P < .0001) for septic and aseptic revision groups, respectively. After controlling for sex, ASA, and number of revisions, PJI diagnosis was a significant mortality predictor (hazard ratio [HR]: 2.69, 95% confidence interval [CI]: 1.5 to 4.7, P = .001). Among PJI patients, age (HR: 1.05, 95% CI: 1.01 to 1.08, P = .009) and ASA (HR: 4.02, 95% CI: 1.67 to 9.67, P = .002) were independent predictors. CONCLUSIONS: Having a revision due to PJI diagnosis was associated with 2.5 times increased mortality. Therefore, more accurate coding capturing the complexity and morbidity of revisions for PJI diagnosis is needed.

The Mark Coventry Award: PhotothermAA Gel Combined With Debridement, Antibiotics, and Implant Retention Significantly Decreases Implant Biofilm Burden and Soft-Tissue Infection in a Rabbit Model of Knee Periprosthetic Joint Infection.

BACKGROUND: Chronic periprosthetic joint infection (PJI) is a major complication of total joint arthroplasty. The underlying pathogenesis often involves the formation of bacterial biofilm that protects the pathogen from both host immune responses and antibiotics. The gold standard treatment requires implant removal, a procedure that carries associated morbidity and mortality risks. Strategies to preserve the implant while treating PJI are desperately needed. Our group has developed an anti-biofilm treatment, PhotothermAA gel, which has shown complete eradication of 2-week-old mature biofilm in vitro. In this study, we tested the anti-biofilm efficacy and safety of PhotothermAA in vivo when combined with debridement, antibiotics and implant retention (DAIR) in a rabbit model of knee PJI. METHODS: New Zealand white rabbits (n = 21) underwent knee joint arthrotomy, titanium tibial implant insertion, and inoculation with Xen36 (bioluminescent Staphylococcus aureus) after capsule closure. At 2 weeks, rabbits underwent sham surgery (n = 6), DAIR (n = 6), or PhotothermAA with DAIR (n = 9) and were sacrificed 2 weeks later to measure implant biofilm burden, soft-tissue infection, and tissue necrosis. RESULTS: The combination of anti-biofilm PhotothermAA with DAIR significantly decreased implant biofilm coverage via scanning electron microscopy compared to DAIR alone (1.8 versus 81.0%; P < .0001). Periprosthetic soft-tissue cultures were significantly decreased in the PhotothermAA with DAIR treatment group (log reduction: Sham 1.6, DAIR 2.0, combination 5.6; P < .0001). Treatment-associated necrosis was absent via gross histology of tissue adjacent to the treatment area (P = .715). CONCLUSIONS: The addition of an anti-biofilm solution like PhotothermAA as a supplement to current treatments that allow implant retention may prove useful in PJI treatment.

Safety Profile of Seven-Day Intra-articular Antibiotic Irrigation for the Treatment of Chronic Periprosthetic Joint Infection: A Prospective Randomized Phase II Comparative Study.

BACKGROUND: Systemic intravenous antimicrobials yield poor outcomes during treatment of periprosthetic joint infection due to the inability to obtain minimum biofilm eradication concentrations. This study evaluated the safety of a novel method of optimized local delivery of intra-articular antibiotics (IAAs). METHODS: This was a Phase II, multicenter, prospective randomized trial evaluating safety of a rapid (seven-day) two-stage exchange arthroplasty with IAA irrigation compared to standard two-stage exchange. The Experimental Group received irrigation using 80 mg tobramycin daily with a 2-hour soak, followed by hourly irrigation using 125 mg vancomycin with a 30-minute soak via an intramedullary irrigation device. The Control Group received an antibiotic-loaded cement spacer with vancomycin (average 8.4 g) and tobramycin (average 7.1 g, total 16 g antibiotics). Both groups received 12 weeks of systemic antibiotics following Stage 2. Safety measures included adverse events, peak vancomycin/tobramycin serum concentrations (Experimental Group), blood transfusion, and mortality. There were thirty-seven patients randomized to the Experimental Group and 39 to control. There was no difference in baseline demographics or comorbidities. RESULTS: There were no antibiotic medication-related adverse events and 2 serious adverse events related to antibiotic instillation. Of 188 vancomycin peak measurements, 69% had detectable serum level concentrations, with all concentrations well below the maximum acceptable trough threshold of 20 µg/mL. Of the 103 tobramycin peak measurements, 45% had detectable levels, with all below the maximum acceptable peak threshold of 18 to 24 µg/mL. There was no difference in blood transfused per subject (Experimental: 655 mL versus Control: 792 mL; P = .4188). There were two (2) deaths in the Experimental Group and four (4) in the control. CONCLUSIONS: The use of IAA is safe with minimal systemic antibiotic exposure. There was no difference in the rates or severity of serious adverse events between groups. Further research is being conducted to examine treatment efficacy.

Impact of Chronic Opioid Use on Postoperative Mobility Recovery and Patient-Reported Outcomes: A Propensity-Matched Study.

BACKGROUND: Opioid use prior to total joint arthroplasty may be associated with poorer postoperative outcomes. However, few studies have reported the impact on postoperative recovery of mobility. We hypothesized that chronic opioid users would demonstrate impaired objective and subjective mobility recovery compared to nonusers. METHODS: A secondary data analysis of a multicenter, prospective observational cohort study in which patients used a smartphone-based care management platform with a smartwatch for self-directed rehabilitation following hip or knee arthroplasty was performed. Patients were matched 2:1 based on age, body mass index, sex, procedure, Charnley class, ambulatory status, orthopedic procedure history, and anxiety. Postoperative mobility outcomes were measured by patient-reported ability to walk unassisted at 90 days, step counts, and responses to the 5-level EuroQol-5 dimension 5-level, compared by Chi-square and student's t-tests. Unmatched cohorts were also compared to investigate the impact of matching. RESULTS: A total of 153 preoperative chronic opioid users were matched to 306 opioid-naïve patients. Age (61.9 ± 10.5 versus 62.1 ± 10.3, P = .90) and sex (53.6 versus 53.3% women, P = .95) were similar between groups. The proportion of people who reported walking unassisted for 90 days did not vary in the matched cohort (87.8 versus 90.7%, P = .26). Step counts were similar preoperatively and 1-month postoperatively but were lower in opioid users at 3 and 6 months postoperatively (4,823 versus 5,848, P = .03). More opioid users reported moderate to extreme problems with ambulation preoperatively on the 5-level EuroQol-5 dimension 5-level (80.6 versus 69.0%, P = .02), and at 6 months (19.2 versus 9.3%, P = .01). CONCLUSIONS: Subjective and objective measures of postoperative mobility were significantly reduced in patients who chronically used opioid medications preoperatively. Even after considering baseline factors that may affect ambulation, objective mobility metrics following arthroplasty were negatively impacted by preoperative chronic opioid use.

Volume and Outcomes of Joint Arthroplasty.

BACKGROUND: Joint arthroplasties are among the most commonly performed elective surgeries in the United States. Surgical outcomes are known to improve with volume but it is unclear whether this has led to consolidation among elective surgeries. We examined trends in volumes per surgeon and hospital to assess whether the known volume-outcome relationship has led to consolidation in elective joint arthroplasty and to determine if there exist volume thresholds above which outcomes do not change. METHODS: Among Medicare beneficiaries who underwent either total knee or total hip arthroplasty from 2009 through 2015, we described volume trends and used mixed-effect models to relate annual surgeon and hospital volumes with 30-day complications or mortality. We tested for optimal volume cut points at both the hospital and surgeon level. RESULTS: Adjusted annual complication rates were inversely associated with volume for both procedures at both the surgeon level and hospital level, but there was minimal consolidation between 2009 and 2015. Complications no longer declined after volumes of each case exceeded 260 per year. The vast majority of cases (around 93% of hip and 88% of knee arthroplasties) were performed by surgeons operating at suboptimal volumes. CONCLUSION: More than 2 decades after the volume-outcome relationship was established for joint arthroplasty, many cases continue to be performed by low-volume surgeons, with far more cases performed by surgeons operating at suboptimal volumes. Further improvement could be expected through consolidation at both the hospital and surgeon level, with a target of at least 260 cases per surgeon annually for each operation. Payers seem best-equipped to drive consolidation.

A Web-Based Interactive Patient-Provider Software Platform Does Not Increase Patient Satisfaction or Decrease Hospital Resource Utilization in Total Knee and Hip Arthroplasty Patients in a Single Large Hospital System.

BACKGROUND: Web-based platforms used to enhance patient-provider communication are being explored to improve patient satisfaction and care delivery, and decrease cost. This study tested a web-based interactive patient-provider software platform (IPSP), JointCOACH, which enabled patient communication with their care team and preparatory/recovery guidance. The aims of this study are to compare (1) patient satisfaction and (2) healthcare resource utilization by patients who underwent total knee and hip replacements and added IPSP to standard of care (SOC). METHODS: This study is a prospective, randomized clinical trial at a single large academic healthcare system. Between May 2018 and March 2020, 399 patients undergoing elective total hip or knee arthroplasty were randomized to SOC arm (n = 204) or SOC + IPSP arm (n = 195). Patient demographics, surgical details, and comorbidities were collected. Patient satisfaction was assessed using Visual Analog Scale and the Picker Patient Experience-15. Healthcare utilization was measured using length of stay, emergency department and office visits, office calls, readmissions, and reoperations at 30 and 90 days after surgery. RESULTS: No difference was found in length of stay between SOC and SOC + IPSP. No differences were found in 30-day or 90-day satisfaction or in healthcare resource utilization (P > .05) including number of office and emergency department visits, phone calls, and readmissions. CONCLUSION: Statistical differences were not found in satisfaction and healthcare utilization with the addition of IPSP to SOC. IPSP can be used to reinforce patient education and communication between the patient and provider, and should be evaluated as an element of virtual care rather than supplementing traditional in-office follow-up. CLINICALTRIALS.GOV: More information on this study can be found at clinicaltrials.gov NCT03499028.

The Effectiveness of Closed-Incision Negative-Pressure Therapy Versus Silver-Impregnated Dressings in Mitigating Surgical Site Complications in High-Risk Patients After Revision Knee Arthroplasty: The PROMISES Randomized Controlled Trial.

BACKGROUND: Revision total knee arthroplasty (rTKA) is associated with significant risk of wound-related morbidity. The present study aimed to evaluate the 1) efficacy of closed-incision negative-pressure therapy (ciNPT) vs silver-impregnated antimicrobial dressing (AMD) in mitigating postoperative surgical site complications (SSCs), 2) the effect of ciNPT vs AMD on certain postoperative health utilization parameters, and on 3) patient-reported outcomes (PROs) improvement at 90-day postoperative follow-up. METHODS: This multicenter randomized controlled trial was conducted between December 2017 and August 2019. Patients ≥22 years, at high risk for SSC, and receiving rTKA with full exchange and reimplantation of new prosthetic components or open reduction and internal fixation of periprosthetic fractures were screened for inclusion. Eligible patients were randomized to receive a commercially available ciNPT system or a silver-impregnated AMD (n = 147, each) for minimum of 5-day duration. Primary outcome was the 90-day incidence of SSCs with stratification in accordance with revision type (aseptic/septic). Secondary outcomes were the 90-day health care utilization parameters (readmission, reoperation, dressing changes, and visits) and PROs. RESULTS: Of 294 patients randomized (age: 64.9 ± 9.0 years, female: 59.6%), 242 (82.0%) patients completed the study (ciNPT: n = 124; AMD: n = 118). The incidence of 90-day SSCs was lower for the ciNPT cohort (ciNPT: 3.4% vs AMD: 14.3%; odds ratio (OR): 0.22, 95% confidence interval (0.08, 0.59); P = .0013). Readmission rates (3.4% vs 10.2%, OR: 0.30(0.11, 0.86); P = .0208) and mean dressing changes (1.1 ± 0.3 vs 1.3 ± 1.0; P = .0003) were lower with ciNPT. The differences in reoperation rates, number of visits, and PRO improvement between both arms were not statistically significant (P > .05). CONCLUSION: ciNPT is effective in reducing the 90-day postoperative SSCs, readmission, and number of dressing changes after rTKA. Recommending routine implementation would require true-cost analyses.

The Quality of Diagnostic Studies in Periprosthetic Joint Infections: Can We Do Better?

BACKGROUND: The diagnosis of periprosthetic joint infections (PJIs) continues to be a subject of extensive debate. This is in part due to the lack of a single "gold standard" test, and the marked heterogeneity in the design of studies evaluating the accuracy of different diagnostic modalities. The goal of this review is to critically analyze the evidence cited by the proceedings of the 2013 International Consensus Meeting (ICM) on PJI with regards to the diagnosis of PJI. METHODS: References from the Proceedings of the ICM on PJI related to PJI minor criteria were retrieved and manually reviewed. A total of 25 studies were analyzed using a Validated Quality Assessment of Diagnostic Accuracy Studies tool. RESULTS: A large number of studies were determined to have a high risk of bias for flow and timing domains due to the large numbers of exclusions. Studies of synovial white blood cells count and polymorphonuclear neutrophils percentage suffered from threshold optimization and lack of internal validity. Furthermore, due to the lack of homogeneity across studies, index test and reference standard domains showed high risk of bias for white blood cell/polymorphonuclear neutrophil percentage and the utility histological analysis, respectively. Leukocyte esterase testing lacked standardization with regard to the strip reagent used, and the exclusion of bloody samples limited sample sizes. CONCLUSION: The 2013 ICM minor criteria were based on studies with a low quality of evidence. As the committee continues to adjust these guidelines, they should encourage future studies with sound clinical design, patient selection, and testing procedures.

Incidence, Causes, and Timing of 30-Day Readmission Following Total Knee Arthroplasty.

BACKGROUND: It is important to study the incidence and causes of readmissions in order to understand why they occur and how to reduce them. This study looks at a national sample of patients following total knee arthroplasty (TKA) to identify incidences, trends, causes, and timing of 30-day readmissions. METHODS: Patients undergoing primary TKA from 2012 to 2016 in the American College of Surgeons National Surgical Quality Improvement Program database were identified (n = 197,192). Patients with fractures (n = 177), nonelective surgery (n = 2234), bilateral TKA (n = 5483), and cases with unknown readmission status (n = 1047) were excluded, leaving a total of 188,251 cases. Linear regression analysis was used to determine trends over time. RESULTS: The incidence of overall 30-day readmission following primary TKA from 2012 to 2016 was 3.19% (6014/188,251), with significant decreases in readmission rates during this time (ß = -0.001, P < .001). The top 5 causes of readmission included superficial surgical site infection (SSI; 9.7%), non-SSI infection (9.5%), cardiovascular complications (CV; 9.3%), gastrointestinal complications (8.8%), and venous thromboembolisms (8.8%). The most common cause of readmission during postoperative week 1 was CV complications (12.2%), week 2 was superficial SSI (11.6%), week 3 was deep SSI (11.4%), and week 4 was deep SSI (12.4%). CONCLUSION: Overall, 30-day readmissions following TKA were found to significantly decline from 2012 to 2016. The most common causes of overall readmission included superficial SSI, non-SSI infection, CV complications, gastrointestinal complications, and venous thromboembolisms. However, the most common causes of readmission changed from week to week postoperatively. This data may help institutions develop policies to prevent unplanned readmissions following TKA.

Clostridium difficile Colitis Following Revision Total Knee Arthroplasty: Incidence and Risk Factors.

BACKGROUND: Clostridium difficile-associated diarrhea (CDAD) is associated with adverse events and financial liability. As institutions continue to adopt CDAD rates as a quality control metric, it is important to identify patients at risk before surgery, including revision total knee arthroplasty (rTKA). This study was conducted to (1) determine the incidence of CDAD within 30 days of rTKA and (2) identify perioperative risk factors for CDAD following rTKA. METHODS: The American College of Surgeons National Surgical Quality Improvement Program was queried to identify 6023 rTKA procedures from 2015-2016. Preoperative and perioperative variables, including patient demographics, lab values, comorbidities, operative time, procedure type, presence of postoperative infections, and rates of CDAD were collected. Chi-square and Fisher's exact tests were used to detect differences between categorical variables, and t-tests were used to compare continuous variables. A stepwise logistic regression model was used to identify the risk factors for CDAD. RESULTS: The rate of CDAD within 30 days of rTKA was found to be 0.4% (24/6024). The CDAD rate following aseptic revision was 0.2% (12/4893), while the incidence of CDAD after septic revision was 1.1% (12/1130). Preoperative functional dependence (odds ratio [OR] = 5.14; P = .002), septic revision (OR = 2.77; P = .026), and cancer (OR = 14.26; P = .016) were statistically significant independent risk factors for CDAD after rTKA. CONCLUSION: The incidence of CDAD after rTKA is approximately 0.4% in the United States. Independent risk factors for CDAD include septic revision, preoperative functional dependence, and cancer. Prevention of CDAD in these higher risk patients must be considered before surgery and antibiotic selection for other infections should be managed judiciously.

Multicenter Evaluation of a Modular Dual Mobility Construct for Revision Total Hip Arthroplasty.

INTRODUCTION: Modular Dual Mobility (MDM) constructs in total hip arthroplasty (THA) offer increased hip stability compared with constrained liners, without compromising hip range of motion. The purpose of this study was to evaluate outcomes of revision THA using MDM. METHODS: The study was a multiinstitutional retrospective cohort study of 315 hips that underwent revision THA using MDM between 2011 and 2017. Clinical outcomes and reasons for failure were collected. RESULTS: Three hundred fifteen patients met 1-year minimum follow-up (mean 3.3 years). Nine hips had instability postoperatively (2.9%), and 30 hips required reoperation (9.5%). Seven had recurrent instability (6.5%) which was associated with liner-only exchange (P = .021) and liner outer diameter of ≤ 38 mm (P = .016). CONCLUSION: Revision THA with MDM provided a low rate of instability and reoperation in a revision cohort. Recurrent instability following use of MDM in revision THA was associated with retention of the acetabular component and polyethylene outer diameter ≤ 38 mm. LEVEL OF EVIDENCE: Therapeutic Level III.

Metaphyseal Fixation Using Highly Porous Cones in Revision Total Knee Arthroplasty: Minimum Two Year Follow Up Study.

BACKGROUND: Highly porous metaphyseal cones have been introduced to restore metaphyseal integrity for improved cement interdigitation to achieve durable fixation in revision total knee arthroplasty (TKA). The purpose of this study is to review the survivorship, clinical results, and complications of revision TKA using highly porous 3-dimensionally printed titanium metaphyseal cones. METHODS: This is a review of 62 revision TKAs using metaphyseal tibial cones, with 15 cases utilizing both tibial and femoral cones. The mean age of the patients was 66 years (range 32-84) who had a mean follow-up of 27 months (range 24-34). There were 38 women and 24 men, who had a mean body mass index of 33 (range 18.3-62). RESULTS: Revision-free survival of the cones was 90.2%. If infection was excluded, survivorship was 100%. There were no cases of aseptic loosening. The mean Knee Society Score improved from 51 points preoperatively to 80 points at the time of latest follow-up. The mean Knee Society Functional Score improved from 48 points preoperatively to 68 points. A total of 15 of the 62 patients (24%) required additional surgery: 10 (16%) for infection, 3 (5%) for contracture, 1 for patellar subluxation, and 1 for quadriceps tendon rupture. CONCLUSION: Metaphyseal fixation is important for survivorship in revision TKA which can be challenging due to cancellous and structural bone loss encountered at the time of revision. Prosthetic joint infection continues to be the leading cause of failure in revision TKA. The use of highly porous titanium metaphyseal cones produced from 3-dimensionally printed technology used in this study demonstrated excellent short-term results with no cases of aseptic loosening. Further follow-up is required to determine if these results can be durable over a longer period.

Influence of Acetabular Shell Position and Component Design on Hip Dynamic Dislocation.

BACKGROUND: Dislocation is a major complication following total hip arthroplasty, with risk factors such as surgical technique, implant positioning, and implant design. Literature has suggested the distance the femoral head must travel before dislocation to be a predictive factor of dislocation where smaller travel distance has increased dislocation risk. The purpose of this study was to compare 3 designs (hemispherical, metal-on-metal, and dual mobility [DM]) in terms of the dynamic dislocation distance and force required to dislocate. METHODS: This dynamic dislocation distance model used a material testing system that defined acetabular component inclination (30°, 45°, and 60°), anteversion angles (0°, 15°, and 30°), and pelvic tilt (5° [standing] and 26° [chair rise]). Testing groups included a hemispherical shell with a modular polyethylene liner and 32-mm head, a metal-on-metal hip resurfacing cup design with a 40-mm CoCr head, and a DM design with a 42-mm outside diameter articulating liner and an inner 28-mm articulating head. RESULTS: The dynamic dislocation distance of the DM hip was greater than that of the other designs for all inclination, anteversion, and pelvic tilt angles tested with the exception of 60° inclination/0° anteversion. At 26° pelvic tilt, it was observed that dislocation distance increased with greater anteversion and decreased with larger inclination. CONCLUSION: Clinical results have shown the DM design may reduce dislocation. These data support those findings and suggest that if instability is a concern preoperatively or intraoperatively, using a DM implant increases the dynamic dislocation distance.

Effects of a Total Knee Arthroplasty Care Pathway on Cost, Quality, and Patient Experience: Toward Measuring the Triple Aim.

BACKGROUND: Care pathways are increasingly important as the shift toward value-based care continues; however, there is an inconsistent literature regarding their efficacy. The authors hypothesized that a total knee arthroplasty (TKA) care pathway, at a multihospital health system, would decrease cost, length of stay (LOS), discharges to inpatient facilities, postoperative complications at 90 days, and improve patient experience. METHODS: A historical control study with multivariable regression was used to determine the association of an evidence-based care pathway with episode of care cost, LOS, discharge disposition, 90-day postoperative complications, and Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) scores. RESULTS: In total, 6760 primary TKA surgeries were analyzed. Multivariable regression demonstrated that the full protocol period was associated with a decrease in episode of care costs (-8.501%, 95% confidence interval [CI] -9.639 to -7.350), a decrease in LOS (-26.966%, 95% CI -28.516 to -25.382), and an increase in discharges to home (odds ratio [OR] 3.838, 95% CI 3.318-4.446). The full protocol was not associated with a change in 90-day complications (OR 1.067, 95% CI 0.905-1.258) or patient willingness to recommend (OR 1.06, 95% CI 0.72-1.55). Adjusted episode of care cost savings, normalized to average national Medicare reimbursement, were $2360 per patient. CONCLUSION: TKA care pathways are an effective tool for standardizing care and reducing costs across a large health system. Further investigations are needed to develop interventions to consistently reduce complications. National scale implementation of care pathways in TKA could lead to estimated cost reductions of approximately $1.6 billion annually.

Are Patients More Satisfied With a Balanced Total Knee Arthroplasty?

BACKGROUND: Patient-reported outcome measures are increasingly recognized as an important tool in quantifying the clinical success of arthroplasty surgery. The aim of this study is to measure post-operative joint awareness and satisfaction in patients with and without a quantitatively balanced knee following primary total knee arthroplasty (TKA). METHODS: In this multi-center study, a total of 318 eligible patients were assigned to one of the 2 patient groups: sensor-guided TKA or surgeon-guided TKA. In the sensor-guided group, quantitative balancing was performed according to intercompartmental tibiofemoral load measurements measured by an instrumented tibial trial component. In contrast, for the surgeon-guided group, the knees were balanced according to the surgeons' standard manual techniques while blinding the surgeon to the sensor measurements. Patients were blinded to their allocation and filled out the validated Forgotten Joint Score and 2011 Knee Society Satisfaction questionnaires at 6 weeks and 6 months. For the purposes of this study, the subjects were pooled and stratified by their state of soft tissue balance, based on the mediolateral load differential through the range of motion. RESULTS: In the surgeon-guided group, approximately 50% of the cases yielded a quantitatively balanced knee. Significantly more balanced knees were observed in the sensor-guided group (84.0%). More importantly, for both outcome measures, the balanced group of patients reported significantly better outcomes scores. CONCLUSION: This demonstrates that using sensor feedback during knee arthroplasty surgery results in a more reproducible procedure, resulting in a higher percentage of balanced patients who in turn demonstrate superior clinical outcomes compared to unbalanced patients.

Older Adults Undergoing Total Hip or Knee Arthroplasty: Chronicling Changes in Their Multimorbidity Profile in the Last Two Decades.

BACKGROUND: Despite the ubiquitous use of total hip arthroplasty (THA) and total knee arthroplasty (TKA) in older adults, little is known about the multimorbidity (MM) profile of this patient population. This study evaluates the temporal trends of MM, hypothesizing that patients with MM have had an increasingly greater representation in THA and TKA patients over time. METHODS: Data on a US representative sample of older adults from the linked Health and Retirement Study and Medicare data from 1993 to 2012 were used. The Health and Retirement Study is a biennial survey that collects data on a broad array of measures, including self-reported chronic conditions and geriatric syndromes, which were used to account for MM. Medicare data were used to identify fee-for-service Medicare beneficiaries who underwent THA (n = 479) or TKA (n = 998) during the study years, which were grouped into 3 periods: 1993-1999, 2000-2006, and 2007-2012. Multivariable logistic regression analysis was conducted to obtain age-, gender-, and race-adjusted time trends for MM. RESULTS: Compared to the earliest study period, and for both THA and TKA patients, there were significantly fewer patients with stroke and/or poor cognitive performance in the most recent study period. In addition, more TKA than THA patients presented with 2+ chronic conditions. Nearly 70% presented with co-occurring chronic conditions and geriatric syndromes, and this percentage did not change significantly over time. CONCLUSION: The high representation of THA and TKA patients presenting with co-occurring chronic conditions and geriatric syndromes in this patient population warrants detailed exploration of the effects of geriatric syndromes on postoperative outcomes.

Periprosthetic joint infection and immunity: Current understanding of host-microbe interplay.

Periprosthetic joint infection (PJI) is a major complication of total joint arthroplasty. Even with current treatments, failure rates are unacceptably high with a 5-year mortality rate of 26%. Majority of the literature in the field has focused on development of better biomarkers for diagnostics and treatment strategies including innovate antibiotic delivery systems, antibiofilm agents, and bacteriophages. Nevertheless, the role of the immune system, our first line of defense during PJI, is not well understood. Evidence of infection in PJI patients is found within circulation, synovial fluid, and tissue and include numerous cytokines, metabolites, antimicrobial peptides, and soluble receptors that are part of the PJI diagnosis workup. Macrophages, neutrophils, and myeloid-derived suppressor cells (MDSCs) are initially recruited into the joint by chemokines and cytokines produced by immune cells and bacteria and are activated by pathogen-associated molecular patterns. While these cells are efficient killers of planktonic bacteria by phagocytosis, opsonization, degranulation, and recruitment of adaptive immune cells, biofilm-associated bacteria are troublesome. Biofilm is not only a physical barrier for the immune system but also elicits effector functions. Additionally, bacteria have developed mechanisms to evade the immune system by inactivating effector molecules, promoting killing or anti-inflammatory effector cell phenotypes, and intracellular persistence and dissemination. Understanding these shortcomings and the mechanisms by which bacteria can subvert the immune system may open new approaches to better prepare our own immune system to combat PJI. Furthermore, preoperative immune system assessment and screening for dysregulation may aid in developing preventative interventions to decrease PJI incidence.

Stepping Up Recovery: Integrating Patient-reported Outcome Measures and Wearable Technology for Rehabilitation Following Knee Arthroplasty.

Improvement after knee arthroplasty (KA) is often measured using patient-reported outcome measures (PROMs). However, PROMs are limited due to their subjectivity. Therefore, wearable technology is becoming commonly utilized to objectively assess physical activity and function. We assessed the correlation between PROMs and step/stair flight counts in total (TKA) and partial knee arthroplasty (PKA) patients.Analysis of a multicenter, prospective, longitudinal cohort study investigating the collection of average daily step and stair flight counts, was performed. Subjects (N = 1,844 TKA patients and N = 489 PKA patients) completed the Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS JR) and provided numerical rating scale pain scores pre- and postoperatively. Only patients who reported living in a multilevel home environment (N = 896 TKA patients and N = 258 PKA patients) were included in analysis of stair flight counts. Pearson correlation coefficients were calculated to determine correlations between variables.Among TKA patients, pain scores demonstrated a negative correlation to mean step counts at preoperative (r = -0.14, p < 0.0001) and 1-month follow-up (r = -0.14, p < 0.0001). Similar negative correlations were true for pain and stair flight counts at preoperative (r = -0.16, p < 0.0001) and 1-month follow-up (r = -0.11, p = 0.006). KOOS JR scores demonstrated weak positive correlations with mean step counts at preoperative (r = 0.19, p < 0.0001) and 1-month postoperative (r = 0.17, p < 0.0001). Similar positive correlations were true for KOOS JR scores and stair flight counts preoperatively (r = 0.13, p = 0.0002) and at 1-month postoperatively (r = 0.10, p = 0.0048). For PKA patients, correlations between pain and KOOS JR with step/stair counts demonstrated similar directionality.Given the correlation between wearable-generated data and PROMs, wearable technology may be beneficial in evaluating patient outcomes following KA. By combining subjective feedback with the objective data, health care providers can gain a holistic view of patients' progress and tailor treatment plans accordingly.