Revision total knee arthroplasty (TKA) procedures performed secondary to periprosthetic joint infection (PJI) are associated with significant morbidity and mortality. These poor outcomes may be further complicated by the development of postoperative infection requiring aggressive antibiotic treatment. However, this antibiotic overuse may suppress patients' native bacterial flora, leading to Clostridium difficile infection (CDI). With the increased demand for primary TKAs and expected rise in revision TKA due to PJI, it is important to identify factors contributing to CDI. Therefore, we aimed to study the: 1) incidence, 2) demographics, length of stay (LOS), and total costs, and 3) risk factors and mortality associated with CDI in revision TKA patients.

The National Inpatient Sample database was queried for all individuals diagnosed with PJI and who underwent revision TKA between 2009 and 2013. Patients who developed CDI during their in-patient hospital stay were identified, yielding 83,806 patients (799 with CDI) with a mean age of 65 (S.D.=11.2). Logistic regression analysis was conducted to assess the association between hospital- and patient-specific characteristics and the development of CDI.

During the study period, the overall incidence of CDI after revision TKA was 1%. These patients were significantly older (mean age 69.05 vs. 65.52 yrs), had greater LOS (median 11 vs. 5 days), had greater costs ($30,612.93 vs. 18,873.75), and had higher in-hospital mortality (3.6 vs. 0.5%, p < 0 .001 for all) compared to those without infection. Patients with CDI were more likely to be treated in urban, not-for-profit, medium or large bed-sized hospitals located in the Northeast or Midwest (p < 0 .05 for all). Patients with underlying depression (OR 4.267, p=0.007) or fluid/electrolyte disorders (OR 3.48, p=0.001) were more likely to develop infection.

Although CDI is a rare event following revision TKA, it can have detrimental consequences. Our report demonstrates that CDI is associated with longer LOS, higher costs, and greater in-hospital mortality. With increased legislative pressure to lower healthcare expenditures, it is crucial to identify means of preventing costly complications.

Despite the widespread success of total hip arthroplasty (THA), postoperative pain management remains a concern. Opioids have classically been administered for pain relief after THA, but their side effect profile, in addition to the cognizance of the growing opioid epidemic, has incited a shift toward alternative pain modalities. Although the nonsteroidal anti-inflammatory drug (NSAID) diclofenac is a promising addition, its impact on immediate THA outcomes has not previously been investigated. Thus, in the present study, we evaluate the effects of adjunctive diclofenac on: 1) postoperative pain intensity, 2) opioid consumption, 3) discharge destination, 4) length of stay, and 5) patient satisfaction in primary THA patients.

A retrospective review was performed to identify all patients who underwent primary THA by a single surgeon between May 1 and September 31, 2017. Patients were stratified into a study group (n=25), who were treated with postoperative diclofenac in addition to the standard pain control regimen, and a control group (n=88), who did not receive adjunctive diclofenac. Repeated-measures analysis of variance (ANOVA)/analysis of covariance (ANCOVA) and chi-square/logistic regression analysis were used for continuous and categorical variables, respectively.

Patients receiving adjunctive diclofenac were more likely to be discharged home than to inpatient facilities (O.R. 4.02, p=0.049). In addition, patient satisfaction with respect to how well and how often pain was controlled (p= 0.0436 and p=0.0217, respectively) was significantly greater in the diclofenac group. Finally, patients who received diclofenac had lower opioid consumption on postoperative days one and two (−67.2 and −129 mg, respectively, p=0.001 for both).

The rapid growth of THA as an outpatient procedure has intensified the urgency of improving postoperative pain management. The present study demonstrates that THA patients receiving adjunctive diclofenac were more likely to be discharged home, had reduced opioid consumption, and experienced greater satisfaction. This will, in turn, decrease complications and total hospital costs, leading to a more cost-effective pain control regimen. In order to further investigate the optimal regimen, future studies comprising larger cohort, as well as a comparison of diclofenac to other NSAIDs, are warranted.

Introduction: Osteonecrosis of the knee occurs with approximately 10% of the incidence of osteonecrosis of the hip. Core decompression is a minimally invasive technique which can potentially forestall bony collapse and thus avoid the need for joint arthroplasty. The purpose of this study was to evaluate the efficacy of a new minimally invasive approach using a small diameter Steinman pin to perform core decompression of the knee.

Materials and Methods: Between September 5, 2000 and May 30, 2003, the senior author performed 55 core decompressions of the knee in 39 patients with symptomatic osteonecrosis of the knee. All procedures were performed using the small-bit drilling technique. There were 32 women and 7 men who had a mean age of 43 years (range, 18 to 52 years). Radiographic and clinical outcomes were assessed during post-operative clinical visits, with persistent pain, loss of joint space, or progression to total knee replacement considered failures.

Results: There were excellent or good outcomes in 45 knees (82%) at a mean three year follow-up (range, 2 to 5 years). Four patients had symptomatic knees that led to total knee arthroplasty. There were no complications from the procedures which were all performed as out-patient surgery.

Discussion: The percutaneous drilling technique appears to be a low-morbidity method of relieving symptoms in patients with symptomatic knees from osteonecrosis. These short-term results are encouraging for this difficult to treat disease.

Introduction: Metal-on-metal resurfacing is a type of total hip arthroplasty that is conservative on the femoral side. It is controversial whether this procedure should be used in patients with avascular necrosis where the femoral resurfacing component is cemented on dead bone. This study analyzed the clinical and radiographic outcome of patients with avascular necrosis treated with metal-on-metal total hip resurfacing arthroplasty.

Materials and Methods: Thirty-seven patients (41 hips) treated with late-stage avascular necrosis of the hip with a metal-on-metal resurfacing hip arthroplasty were studied. There were 27 men and 10 women who had a mean age of 40 years (range, 16 to 62 years). Patients were followed both clinically and radiographically for a minimum of two years (mean of 3 years).

Results: Overall, there were good and excellent clinical outcomes in 38 hips (93%). Fair results were found in three patients who had excessive heterotopic bone (2 hips) and persistent groin pain (1 hip). There were no cases of component loosening. Radiographic zonal analysis revealed no evidence of impending failure or progressive radiolucencies.

Discussion: Excellent short-term results were found with metal-on-metal total hip resurfacing in this difficult patient population. The authors await long-term results to see if these early excellent results are maintained.

Introduction: The results of total hip arthroplasty in patients with avascular necrosis of the hip have been variable. This study analyzed the clinical and radiographic outcome of young patients (mean age of 39 years) treated with a proximally hydroxyapatite-coated tapered stem.

Materials and Methods: Sixty-seven patients (84 hips) treated with late-stage avascular necrosis of the hip with a proximally hydroxyapatite-coated tapered stem as part of their total hip arthroplasty was studied. There were 41 men and 26 women who had a mean age of 39 years (range, 18 to 80 years). Patients were followed both clinically and radiographically for a minimum of two years (mean of 3 years).

Results: Overall, there were good and excellent clinical outcomes in 78 hips (93%). Fair results were found in five patients with persistent pain. There was only one stem loosening (obese patient with SLE). Radiographic zonal analysis revealed no evidence of impending failure or progressive radiolucencies.

Discussion: Excellent short-term results were found with total hip arthroplasty in this difficult patient population. The proximally hydroxyapatite-coated tapered stem utilized in this study was useful in patients with avascular necrosis of the hip.