Positive Culture of Atypical Mycobacterium Avium Following Revision Total Knee Arthroplasty.

CASE: We report a rare case of mycobacterial periprosthetic joint infection (PJI) after primary total knee arthroplasty 14 years earlier. Progressive knee pain over three years with a negative PJI infectious workup led to revision total knee arthroplasty. A surprising result was isolation of Mycobacterium avium from tissue cultures taken at time of revision surgery. After six months of antibiotic treatment, the patient is alive with well- functioning pain-free TKA at over one-year follow-up. CONCLUSION: Periprosthetic joint infection can present acutely or chronically years following total knee arthroplasty. Depending on the infecting organism, patients can present with sepsis, or a more indolent slower course that mimics aseptic loosening. In the absence of positive pre-operative labs and cultures, and based on the Musculoskeletal Infection Society (MSIS) criteria, aseptic loosening is a diagnosis of exclusion. An atypical infectious organism should be considered a possible cause and may require specialized cultures of operative specimens.

Tibial Component Revision Arthroplasty Using Porous Tantalum Cone for Symptomatic Progressive Periprosthetic Proximal Tibial Ganglion Cyst about All-Polyethylene Tibia Primary Total Knee Replacement: A Case Report and Review of Literature.

Introduction: Intraosseous ganglion cysts are an uncommon variant found in the subchondral bone. We report here the development of an intraosseous ganglion cyst of the proximal tibia in the setting of a prior left total knee arthroplasty (TKA) with an all-polyethylene tibial component. Case Report: The cyst was diagnosed on routine follow-up radiographs approximately 4 years status post-TKA. Although initially asymptomatic, 1 year later the patient presented with progressive knee pain and ambulation limitations, so revision TKA was indicated. Computed tomography confirmed an osteolytic lesion suggestive of a penetrating ganglion. Given the absence of malrotation or malalignment of the well-fixed femoral component, the decision was made to proceed with tibial revision to stemmed component cemented through a porous tantalum cone. Postoperatively, the patient had complete resolution of pain and instability with 0-120° of stable range of motion, which has persisted to the latest follow-up at over 6 months post-operative, with radiographic resolution of the cyst. Conclusion: This case demonstrates a ganglion cyst surrounding total knee implants as a possible source of persistent pain following TKA. To our knowledge, this is the first report of such a case. This case demonstrates that refractory painful knee implants secondary to tibial ganglion cysts can be treated successfully with revision arthroplasty.

The Immediate Impact of Total Knee Arthroplasty Removal From the Medicare Inpatient-Only List on Patient Derived Functional Outcomes and Hospital Satisfaction.

BACKGROUND: Total knee arthroplasty (TKA) is the standard of treatment for end-stage knee osteoarthritis. On January 1, 2018, the Centers for Medicare and Medicaid (CMS) officially removed TKA from their inpatient-only list. The clinical impact of this change is not fully understood yet. METHODS: Electronic records were retrospectively reviewed for patients who underwent TKA between January 1 to June 30, 2017, or January 1 to June 30, 2018. Patients completed Function and Outcomes Research for Comparative Effectiveness in Total Joint Replacement surveys which assessed patient reported outcomes prior to and following TKA. Hospital statistics for the 2 time points were determined and compared. This was a single institution study resulting in 351 patients in the pre-CMS change group and 350 patients in the post-CMS change group. RESULTS: Analysis of the pre-CMS and post-CMS transition cohorts indicated no significant difference in activities of daily living (ADLs), pain, or pain catastrophizing scale preoperatively or 12-months postoperatively. Additionally, there was no difference in the median change between preoperative and postoperative ADL scores (P = .866), yet pain scores approached significance with a P value of .054. The pre-CMS transition group stayed significantly longer in the hospital postoperatively and was more commonly discharged to a skilled nursing facility. No difference was seen in 30-day readmission rates (P = .253). CONCLUSIONS: Results showed that patients had similar scores for ADL, quality of life, pain, and pain catastrophizing 12-months following their TKA. Movement of TKA from the Medicare inpatient only list did not have an immediate negative impact for patient reported outcomes and 30-day readmissions at our institution in the 6-month transition period.

Mechanically stable rifampin antibiotic cement inhibits Pseudomonas aeruginosa biofilm surface growth.

Rifampin has been proven to be effective in the treatment of prosthetic infections due to its ability to intercalate into biofilms. The use of rifampin in antibiotic spacers is not well described, which would be especially important in the local periprosthetic environment where parenteral doses have poor penetration. The null hypothesis tests if rifampin use in polymethyl methacrylate (PMMA) cement will show no clinically significant impact on mechanical strength at antibiotic concentrations that remain bactericidal. Test antibiotic cement samples supplemented with 0, 30, 50, 100, 150, or 200 mg of rifampin into a standard 40 g bag were tested for compression to failure using published ASTM standards. The samples were then inoculated with Pseudomonas aeruginosa and either evaluated for lipopolysaccharide (LPS) presence as a marker of biofilm or tested by elution as the Kirby Bauer assay. Rifampin concentrations of 30 and 50 mg, showed no statistically different mechanical characteristics from control PMMA (p > 0.05). The 100-mg sample fell within the acceptable range of compressive strength and had significantly less LPS and bacterial presence compared to the control at 12 and 24 h. The ability of PMMA with 100 mg of rifampin to maintain its structural integrity and have significant bacterial inhibition at 12 and 24 h makes it a great candidate as an antibiotic bone cement additive. PMMA loaded with up to 100 mg of rifampin shows promise in the treatment and prevention of periprosthetic joint infection for total knee and total hip arthroplasty.

Shoulder Adhesive Capsulitis Prior to Total Knee Arthroplasty is Associated With Increased Rates of Postoperative Stiffness Requiring Manipulation Under Anesthesia and Arthroscopic Lysis of Adhesions.

BACKGROUND: Arthrofibrosis following total knee arthroplasty (TKA) and adhesive capsulitis (AC) of the shoulder develop via a similar pathologic process. The purpose of this study was to examine the relationship between these two conditions. METHODS: This was a retrospective cohort study using a large nationwide claims database. Patients who had a history of shoulder AC prior to TKA were compared to TKA patients who did not have AC history comparing rates of postoperative stiffness, manipulation under anesthesia (MUA), arthroscopic lysis of adhesions (LOAs), and revision arthroplasty at postoperative timepoints (3 months, 6 months, 1 year, and 2 years). RESULTS: Within 3 months, 6 months, 1 year, and 2 years of their TKAs, patients who had a history of AC prior to TKA were significantly more likely to experience stiffness (OR [odds ratio] = 1.29, 1.28, 1.32, and 1.36, respectively) and LOAs (OR = 6.78, 3.65, 2.99, and 2.81, respectively). They also showed increased risk of MUA within 6 months, 1 year, and 2 years (OR = 1.15, 1.15, and 1.16, respectively) of their TKAs. Patients having a preoperative diagnosis of AC did not have an increased risk of undergoing revision surgery 1 year or 2 years after their TKAs (P > .05). CONCLUSIONS: Patients diagnosed with AC prior to TKA experience higher rates of postoperative stiffness, resulting in additional interventions such as MUA and LOAs. These findings identify a particularly high-risk patient population that may benefit from additional interventions prior to and following TKA. LEVEL OF EVIDENCE: This is a level III prognostic study.

The Effect of Surgical Approach on the Outcomes of Same-Day Discharge Outpatient Total Hip Arthroplasty at a Single Ambulatory Surgery Center.

BACKGROUND: Primary total hip arthroplasty (THA) is increasingly being performed in the outpatient setting. However, there is little known regarding the differences in same-day discharge (SDD) rates and complications of operative approach in same-day total hip arthroplasty in the ambulatory surgery center (ASC) setting. METHODS: A retrospective chart review was performed between July 2019 and October 2021 for all patients who underwent primary THA in a single freestanding ASC. Successful SDDs, surgical approaches, lengths of surgery, estimated blood losses (EBL), complications, and readmission events were recorded for each patient. Complications were compared using Pearson Chi-Squares, while EBL and surgery lengths were compared with 1-way analysis of variances (ANOVA) (alpha = 0.5). There were 17 total complications in 326 total hip arthroplasties (5.2%), including direct admissions to the emergency department, 30-day and 90-day readmissions, wound complications, instability, infection, and revision surgery. Among all complications, there were 5 direct admissions, making the successful SDD rate 98.5%. RESULTS: Complications and direct admissions were not associated with approach. The 30-day readmission rates were associated with approach, with no readmissions in the direct anterior approach (DAA) or the antero-lateral approach (AL) cohorts and 3 (4.3%) in the posterior approach (PA) cohort. CONCLUSIONS: In the ASC setting, patients undergoing THA regardless of approach showed no difference in successful SDDs or complications aside from 30-day readmissions. Same-day THA can be safely performed in the DAA, AL, and PA to the hip.

Chronic obstructive pulmonary disease is an independent risk factor for increased opioid use in total hip arthroplasty: A retrospective PearlDiver study.

Background: Total hip arthroplasty (THA) has become an incredibly common procedure due to its' predictability and high success rate. The success of surgery is related to strict indications and careful optimization of medical comorbidities to decrease risk and improve outcomes. Chronic obstructive pulmonary disease (COPD) has been associated with increased medical and surgical complications. A regulatory focus on opioid utilization does not usually consider COPD as a risk factor, but limited research exists on the impact of COPD on outcomes and risks after THA. Methods: Retrospective all-inclusive database analysis of Medicare patients who had undergone THA between 2007 and 2017 included in the PearlDiver Database were studied. Postoperative opioid usage was examined at 1-, 3-, 6-, and 12 months, along with surgical infection, implant complications, and revisions. Post-operative complications within 30 days, either medical or implant related, were identified. Controlling for comorbidities, age, and sex, odds ratios were calculated using multivariable logistic regression with a significant α value of 0.05. Results: COPD patients had significantly higher rates of opioid usage postoperatively. COPD patients also had an increased rate of readmissions, medical/implant complications, and revision surgeries. Discussion: This is the only study raising concern regarding opioid use in COPD patients after total hip arthroplasty, which may be critical considering the associated respiratory depression further exacerbating the COPD. Considering the evidence of poor outcomes associated with COPD in arthroplasty, appropriately screening for COPD and counseling or planning for post-operative pain control and complications is paramount.

Older age and smaller joint space width are associated with conversion to total hip arthroplasty following hip arthroscopy.

Purpose: The goal of this study was to define the outcomes of patients following hip arthroscopy and to identify potential factors, found during hip arthroscopy, that were associated with patients' eventual conversion to total hip arthroplasty (THA). Methods: Patients who had undergone hip arthroscopy from January 2010 to January 2015 were retrospectively reviewed and patients were reported if they had a THA in the same hip. Patients were followed up to December 2022 resulting in between 7 and 12 years of follow-up. Measures from the hip scope including joint space width and cartilage grades were reported. Differences in these measures and demographics were compared between patients who had THA after hip arthroscopy and those who did not with T-tests. Results: Patients who had hip arthroscopy and were then converted to THA were significantly older than those patients who did not have THA (50.3 vs 42.0 years) (p = 0.039). The average time of conversion to THA from index hip arthroscopy was 3.59 years with a range of 0.48-8.91 years. Joint space width in patients converted to THA was significantly less, 3.08 mm ± 1.93 mm, compared to non-THA converted patients, 3.62 mm ± 0.88 mm (p < 0.001). Conclusions: Older age and smaller joint space width of the hip was associated with patients who were converted to THA following hip arthroscopy. Level of evidence: Level III.

Medial Calcar Restoration Using Femoral Head Autograft in Conversion Hip Arthroplasty for Failed Fixation after an Unstable Intertrochanteric Hip Fracture: A Case Report and Technique Description.

Introduction: The calcar femorale helps manage compressive loads on the femoral head and is an essential component in determining intertrochanteric (IT) femur fracture stability. Fracture fixation can be complicated when primary fixation techniques, such as cephalomedullary nailing fail. Unstable IT femur fractures involving disruption of the medial calcar present additional fixation challenges. Case Report: This case reports a patient with unstable IT fracture due to medial calcar disruption that experienced failure of a short cephalomedullary nail. Secondary fixation involved total hip arthroplasty (THA) with medical calcar reconstruction using femoral head autograft. Outcomes were good at 2-year follow-up with a full return to baseline activities. Conclusion: The results indicate that femoral head autografting can be a viable option, with good outcomes, for medial calcar reconstruction in cases of failed IT fracture fixations without calcar support, converted to THA.

Cutaneous Paraneoplastic Syndrome Affecting the Hand in a Case of Underlying Waldenström Macroglobulinemia.

Paraneoplastic syndromes represent the body's immune response to an underlying malignancy. The autoimmune response to cancer can manifest itself in multiple ways, including swelling, thickening, and changes in the hand. We report the case of a 65-year-old man who presented with hand swelling that was initially attributed to a work-related finger laceration. The patient developed edema and stiffness in the hand, which was subsequently diagnosed as Waldenström macroglobulinemia. Hand surgeons should be aware that atypical hand and wrist symptoms should raise the suspicion for the potential of a paraneoplastic syndrome and an underlying malignancy.

Obesity and total joint arthroplasty: Does weight loss in the preoperative period improve perioperative outcomes?

BACKGROUND: The obese population is more likely to develop degenerative joint disease requiring total joint arthroplasty (TJA) and also experience increased rates of adverse post-surgical outcomes. This study assessed whether a quantifiable weight loss prior to TJA had any impact on perioperative and 30-day outcomes in obese patients. METHOD: Using the American College of Surgeons-National Surgical Quality Improvement Program database, obese patients who underwent total hip or total knee arthroplasty and lost at least 10% of their total body weight prior to surgery were identified and matched to other obese individuals undergoing the same procedures without weight loss. Perioperative outcomes, including operative time, length of stay, discharge destination, or 30-day adverse events, including complications, re-admissions, re-operations, and mortality, were then compared using conditional Logistic regression analysis. RESULTS: Analysis showed no difference between the two groups in terms of operative time, length of stay, discharge destination, or 30-day adverse events, including complications, re-admissions, re-operations, and mortality. CONCLUSION: The results of this study suggest that weight loss alone in the preoperative period may not be sufficient to mitigate the effects of obesity on immediate post-TJA outcomes.

Oleic acid restores suppressive defects in tissue-resident FOXP3 Tregs from patients with multiple sclerosis.

FOXP3+ Tregs rely on fatty acid ß-oxidation-driven (FAO-driven) oxidative phosphorylation (OXPHOS) for differentiation and function. Recent data demonstrate a role for Tregs in the maintenance of tissue homeostasis, with tissue-resident Tregs possessing tissue-specific transcriptomes. However, specific signals that establish tissue-resident Treg programs remain largely unknown. Tregs metabolically rely on FAO, and considering the lipid-rich environments of tissues, we hypothesized that environmental lipids drive Treg homeostasis. First, using human adipose tissue to model tissue residency, we identified oleic acid as the most prevalent free fatty acid. Mechanistically, oleic acid amplified Treg FAO-driven OXPHOS metabolism, creating a positive feedback mechanism that increased the expression of FOXP3 and phosphorylation of STAT5, which enhanced Treg-suppressive function. Comparing the transcriptomic program induced by oleic acid with proinflammatory arachidonic acid, we found that Tregs sorted from peripheral blood and adipose tissue of healthy donors transcriptomically resembled the Tregs treated in vitro with oleic acid, whereas Tregs from patients with multiple sclerosis (MS) more closely resembled an arachidonic acid transcriptomic profile. Finally, we found that oleic acid concentrations were reduced in patients with MS and that exposure of MS Tregs to oleic acid restored defects in their suppressive function. These data demonstrate the importance of fatty acids in regulating tissue inflammatory signals.

Sex-Specific Differences of Steroid Receptors Following Exposure to Environmentally Relevant Concentrations of Phenothiazine in Fundulus heteroclitus.

Phenothiazine (PTZ) is a heterocyclic thiazine compound used for industrial and medical purposes. Through environmental surveillance studies, PTZ was found being discharged into a local river in Connecticut. Phenothiazine has been shown to act similarly to endocrine disrupting chemicals. This study sought to identify sex specific hormone receptor changes in Fundulus heteroclitus in response to PTZ exposure. Fundulus heteroclitus, also known as mummichog, are small fish native to the Atlantic coast of the United States and Canada. They reside in brackish waters and can survive harsh toxic environments. This model organism is native to the polluted waters found in Connecticut. In this study, fish were exposed to PTZ concentrations of 0.5 ppm, 1.0 ppm, and 2.0 ppm for 1 week. Following exposure, brain, liver, and gonad tissues were harvested; cDNA was synthesized; and mRNA expression was assessed for 6 different hormone receptors. Compared with vehicle control (ethanol) differences in mRNA expression, levels of hormone receptors were observed in various tissues from male and female fish. Many of the tissues assessed showed changes in expression level, while only female liver and testis showed no change. These results implicate PTZ as a potential endocrine disrupting compound to mummichog at environmentally relevant concentrations.