Faculty Bibliography

BACKGROUND:Periprosthetic joint infections (PJIs) following total hip arthroplasty (THA) and total knee arthroplasty (TKA) are associated with substantial morbidity. A better understanding of the costs of PJI treatment can inform prevention, treatment, and reimbursement strategies. The purpose of the present study was to describe direct inpatient medical costs associated with the treatment of hip and knee PJI. METHODS:At a single tertiary care institution, 176 hips and 266 knees that underwent 2-stage revisions for the treatment of PJI from 2009 to 2015 were compared with 1,611 hips and 1,276 knees that underwent revisions for aseptic indications. In addition, 84 hips and 137 knees that underwent irrigation and debridement (I&D) with partial component exchange were compared with 39 hips and 138 knees that underwent partial component exchange for aseptic indications. Line-item details of services billed during hospitalization were retrieved, and standardized direct medical costs were calculated in 2018 inflation-adjusted dollars. RESULTS:The mean direct medical cost of 2-stage revision THA performed for the treatment of PJI was significantly higher than that of aseptic revision THA ($58,369 compared with $22,846, p < 0.001). Similarly, the cost of 2-stage revision TKA performed for the treatment of PJI was significantly higher than that of aseptic revision TKA ($56,900 compared with $24,630, p < 0.001). Even when the total costs of aseptic revisions were doubled for a representative comparison with 2-stage procedures, the costs of PJI procedures were 15% to 28% higher than those of the doubled costs of aseptic revisions (p < 0.001). The mean direct medical cost of I&D procedures for PJI was about twofold higher than of partial component exchange for aseptic indications. CONCLUSIONS:The direct medical costs of operative treatment of PJI following THA and TKA are twofold higher than the costs of similar aseptic revisions. The high economic burden of PJI warrants efforts to reduce the incidence of PJI. Reimbursement schemes should account for the high costs of treating PJI in order to ensure sustainable patient care. LEVEL OF EVIDENCE/METHODS:Economic Level IV. See Instructions for Authors for a complete description of levels of evidence.

UNLABELLED:Cutibacterium periprosthetic joint infections are important complications of shoulder arthroplasty. Although it is known that these infections are more common among men and that they are more common in patients with high levels of Cutibacterium on the skin, the possible relationship between serum testosterone levels and skin Cutibacterium levels has not been investigated. METHODS:In 51 patients undergoing shoulder arthroplasties, total serum testosterone, free testosterone, and sex hormone binding globulin levels obtained in the clinic before the surgical procedure were compared with the levels of Cutibacterium on the skin in clinic, on the skin in the operating room prior to the surgical procedure, and on the dermal wound edge of the incised skin during the surgical procedure. RESULTS:Clinic skin Cutibacterium loads were strongly associated with both clinic free testosterone levels (tau, 0.569; p < 0.001) and total serum testosterone levels (tau, 0.591; p < 0.001). The prepreparation skin and wound Cutibacterium levels at the time of the surgical procedure were also significantly associated with both the clinic total serum testosterone levels (p < 0.001) and the clinic free testosterone levels (p < 0.03). A multivariate analysis demonstrated that serum testosterone was an independent predictor of high skin Cutibacterium loads, even when age and sex were taken into account. Patients taking supplemental testosterone had higher free testosterone levels and tended to have higher skin Cutibacterium loads. Patients who underwent the ream-and-run procedure had higher total and free testosterone levels and higher skin Cutibacterium loads. CONCLUSIONS:Testosterone levels are predictive of skin Cutibacterium levels in patients undergoing shoulder arthroplasty. This relationship deserves further investigation both as a risk stratification tool and as a potential area for intervention in reducing shoulder periprosthetic joint infection. LEVEL OF EVIDENCE/METHODS:Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

BACKGROUND:Patients with femoroacetabular impingement (FAI) may experience lasting clinical improvement after hip arthroscopy; however, some patients will still eventually undergo early conversion to THA due to unresolved symptoms and progression of arthritis. However, the risk of this has been only incompletely characterized in prior studies. QUESTIONS/PURPOSES:Using a large healthcare claims database over a 5-year period (2011-2016), we asked: (1) What is the survivorship free from THA after arthroscopic osteoplasty performed for FAI? (2) What identifiable demographic factors and patient characteristics are associated with early conversion to THA after hip arthroscopy performed for FAI? METHODS:We included all patients who underwent hip arthroscopy for FAI, between the ages of 12 years and 63 years, with 3 months of claims data before hip arthroscopy and minimum 2-year follow-up. A total of 4730 hip arthroscopy patients from 2011 to 2014 were retrieved from a US commercial claims database. Hip arthroscopy incidence doubled over time from 1.2 to 2.1 persons per 100,000. Temporal trends, patient demographics, diagnoses at time of arthroscopy, and patient comorbidities were retrieved and logistic regression performed. Survivorship analysis on 11,323 patients (lifting the 2-year follow-up requirement) was also performed to identify independent variables associated with early risk of conversion to THA. RESULTS:In patients undergoing hip arthroscopy for FAI, the overall proportion of conversion to THA within 2 years after hip arthroscopy was 7% (338 of 4730). After controlling for confounding variables such as sex, obesity, and depression, we found the following were independently associated with increased odds of conversion to THA: older age (odds ratio 1.08 [95% CI 1.01 to 1.10]; p < 0.001), osteoarthritis (OR 2.91 [95% CI 2.27 to 3.77]; p < 0.001), joint inflammation (OR 1.89 [95% CI 1.16 to 3.09]; p = 0.01), and a history of opioid use (OR 2.17 [95% CI 1.69 to 2.79]; p < 0.001). Survivorship analysis similarly revealed that older age (hazard ratio 1.08 [95% CI 1.07 to 1.09]; p < 0.001), osteoarthritis (HR 2.53 [95% CI 2.13 to 3.01]; p < 0.001), joint inflammation (HR 1.53 [95% CI 1.10 to 2.11]; p = 0.01), a history of opioid use (HR 2.02 [95% CI 1.71 to 2.38]; p < 0.001), and smoking (HR 1.55 [95% CI 1.14 to 2.11]; p = 0.005), were independently associated with increased odds of conversion to THA within 2 years after hip arthroscopy for FAI. CONCLUSIONS:Although the findings of this study are limited and should not be taken in isolation, patients with FAI who are older, carry diagnoses of inflammatory or degenerative articular disease, or who use opioids or smoke should be counseled about a potentially increased risk of undergoing early conversion to THA after hip arthroscopy. Future studies to further examine the effect of these diagnoses in prospectively collected cohorts, incorporating radiographic and patient-reported outcome measures, are needed. LEVEL OF EVIDENCE:Level III, prognostic study.

The measurement of circulating metal ion levels in total hip arthroplasty patients continues to be an area of clinical interest. National regulatory agencies have recommended measurement of circulating cobalt and chromium concentrations in metal-on-metal bearing symptomatic total hip arthroplasty patients. However, the clinical utility of serum titanium (Ti) measurements is less understood due to wide variations in reported values and methodology. Fine-scale instrumentation for detecting in situ Ti levels continues to improve and has transitioned from graphite furnace atomic absorption spectroscopy to inductively coupled plasma optical emission spectrometry or inductively coupled plasma mass spectrometry. Additionally, analytical interferences, variable sample types, and non-standardized sample collection methods complicate Ti measurement and underlie the wide variation in reported levels. Normal reference ranges and pathologic ranges for Ti levels remain to be established quantitatively. However, before these ranges can be recognized and implemented, methodological standardization is necessary. This paper aims to provide background and recommendations regarding the complexities of measurement and interpretation of circulating Ti levels in total hip arthroplasty patients.

BACKGROUND:When performing revision shoulder arthroplasty, surgeons do not have access to the results of intraoperative culture specimens and will administer empiric antibiotics to cover for the possibility of deep infection until the culture results are finalized. The purpose of this study was to report the factors associated with the initiation, modification, and adverse events of 2 different postoperative antibiotic protocols in a series of revision shoulder arthroplasties. METHODS:In this study, 175 patients undergoing revision shoulder arthroplasty were treated with either a protocol of intravenous (IV) antibiotics if there was a high index of suspicion for infection or a protocol of oral antibiotics if the index of suspicion was low. Antibiotics were withdrawn if cultures were negative and were modified as indicated if the cultures were positive. Antibiotic course, modification, and adverse effects to antibiotic administration were documented. RESULTS:On univariate analysis, factors significantly associated with the initiation of IV antibiotics were male sex (p < 0.001), history of infection (p < 0.001), intraoperative humeral loosening (p = 0.003), and membrane formation (p < 0.001). On multivariate analysis, male sex (p = 0.003), history of infection (p = 0.003), and membrane formation (p < 0.001) were found to be independent predictors of the initiation of IV antibiotics. On the basis of preoperative and intraoperative characteristics, surgeons anticipated the culture results in 75% of cases, and modification of antibiotic therapy was required in 25%. The modification from oral to IV antibiotics due to positive culture results was made significantly more often in male patients (p < 0.001). Adverse effects of antibiotic administration occurred in 19% of patients. The rates of complications were significantly lower in the patients treated with oral antibiotics and a shorter course of antibiotics (p < 0.001). CONCLUSIONS:Complications associated with antibiotic administration after revision shoulder arthroplasty are not infrequent and are more common in patients whose initial protocol is IV antibiotics. Further study is needed to balance the effectiveness and risks of post-revision antibiotic treatment given the frequency of antibiotic-related complications. LEVEL OF EVIDENCE/METHODS:Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

AIMS:Options for the treatment of intra-articular ligament injuries are limited, and insufficient ligament reconstruction can cause painful joint instability, loss of function, and progressive development of degenerative arthritis. This study aimed to assess the capability of a biologically enhanced matrix material for ligament reconstruction to withstand tensile forces within the joint and enhance ligament regeneration needed to regain joint function. MATERIALS AND METHODS:A total of 18 New Zealand rabbits underwent bilateral anterior cruciate ligament reconstruction by autograft, FiberTape, or FiberTape-augmented autograft. Primary outcomes were biomechanical assessment (n = 17), microCT (µCT) assessment (n = 12), histological evaluation (n = 12), and quantitative polymerase chain reaction (qPCR) analysis (n = 6). RESULTS:At eight weeks, FiberTape alone or FiberTape-augmented autograft demonstrated increased biomechanical stability compared with autograft regarding ultimate load to failure (p = 0.035), elongation (p = 0.006), and energy absorption (p = 0.022). FiberTape-grafted samples also demonstrated increased bone mineral density in the bone tunnel (p = 0.039). Histological evaluation showed integration of all grafts in the bone tunnels by new bone formation, and limited signs of inflammation overall. A lack of prolonged inflammation in all samples was confirmed by quantification of inflammation biomarkers. However, no regeneration of ligament-like tissue was observed along the suture tape materials. Except for one autograft failure, no adverse events were detected. CONCLUSION:2019;101-B:1238-1247.

BACKGROUND:The purpose of this study was to compare 2-year BMI changes between patients undergoing simultaneous bilateral total knee arthroplasty (TKA), staged bilateral TKA, and unilateral TKA. We also sought to determine the predictors of weight change and whether clinically meaningful weight changes affected outcomes. PATIENTS AND METHODS/METHODS:This retrospective, single-institution study included 202 Chinese patients who received simultaneously bilateral TKA, staged bilateral TKA, or unilateral TKA from 2008 to 2015. There were 49 simultaneous bilateral TKAs, 52 staged bilateral TKAs, and a matched 101 unilateral TKAs. RESULTS:66.8% (135/202) of patients lost weight after TKA surgery. However, 20.7% (42/202) of patients experienced clinically meaningful weight loss (a BMI decrease of more than 5%). Paired t test showed that 2-year BMI was significantly lower than preoperative BMI (p < 0.001). Weight loss was significantly different between the surgical strategy (p < 0.001). Preoperative BMI and age were predictive of clinically significant weight loss or gain (p < 0.05). Multiple linear regression showed that post-operative weight loss was associated with better Western Ontario and McMaster Universities Osteoarthritis Index and SF-36 scores (p < 0.001). CONCLUSION/CONCLUSIONS:Patients after TKA experience weight loss. Age and preoperative BMI predict clinically meaningful weight change. Simultaneous bilateral TKA is associated with higher likelihood of weight loss. Clinically meaningful weight loss experiences better patient-reported outcomes.

BACKGROUND:Revision total hip arthroplasty (revision THA) occurs for a wide variety of indications and in the United States it is coded under Diagnosis-Related Groups (DRGs) 466, 467, and 468, which do not account for revision etiology, a potentially substantial driver of cost. This study investigates revision THA costs and 30-day complications by indication, both locally and nationally. METHODS:Hospitalization costs and complication rates for 1,422 aseptic revision THAs performed at a high-volume center between 2009 and 2014 were retrospectively reviewed. Additionally, charges for 28,133 revision THAs in the National Inpatient Sample (NIS) were converted to costs using the Healthcare Cost and Utilization Project cost-to-charge ratios, and 30-day complication rates for 3,224 revision THAs were obtained with use of the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP). Costs and complications were compared between revision THAs performed for fracture, wear/loosening, and dislocation/instability with use of simultaneous and pairwise comparisons and a multivariable model accounting for American Society of Anesthesiologists (ASA) score, age, and sex. RESULTS:Local hospitalization costs for fracture (median, $25,672) were significantly higher than those for wear/loosening ($20,228; p < 0.001) or dislocation/instability ($17,911; p < 0.001), with differences remaining significant even after adjusting for patient comorbidities (p < 0.001). NIS costs for fracture (median, $27,596) were higher than those for other aseptic indications (wear/loosening: $21,176, p < 0.001; dislocation/instability: $16,891, p< 0.001). Local 30-day orthopaedic complication rates for fracture (20.7%) were higher those than for dislocation/instability (9.0%; p = 0.007) and similar to those for wear/loosening (17.6%; p = 0.434). Nationally, combined medical and surgical complication rates for fracture (71.3% of patients with ≥1 complication) were significantly higher than those for wear/loosening (35.2%; p < 0.001) or dislocation/instability (35.1%; p < 0.001). CONCLUSIONS:Hospitalization costs for revision THA for fracture were 33% to 48% higher than for all other aseptic revision THAs, both locally and nationally. This increased cost persisted even after multivariable comorbidity adjustment, the current DRG basis for stratifying revision THA reimbursement. Additionally, 30-day complication rates suggest that increased resource utilization for fracture patients continues even after discharge. Indication-specific coding and reimbursement systems are necessary to maintain sustainable access to revision THA for all patients. LEVEL OF EVIDENCE/METHODS:Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

BACKGROUND:Long-term mortality following primary total knee arthroplasty (TKA) is lower than the general population. However, it is unknown whether this is true in the setting of revision TKA. We examined long-term mortality trends following revision TKA. METHODS:This retrospective study included 4907 patients who underwent 1 or more revision TKA between 1985 and 2015. Patients were grouped by surgical indications and followed until death or October 2017. The observed number of deaths was compared to the expected number of deaths using standardized mortality ratios (SMR) and Poisson regression models. RESULTS:Compared to the general population, patients who underwent revision TKA for infection (SMR, 1.45; 95% confidence interval [CI], 1.33-1.57; P < .0001) and fracture (SMR, 1.16; 95% CI, 1.00-1.34; P = .04) experienced a significantly higher mortality risk. Patients who underwent revision TKA for infection and fracture experienced excess mortality soon after surgery which became more pronounced over time. In contrast, the mortality risk among patients who underwent revision TKA for loosening and/or bearing wear was similar to the general population (SMR, 0.95; 95% CI, 0.89-1.02; P = .16). Aseptic loosening and/or wear and instability patients had improved mortality initially; however, there was a shift to excess mortality beyond 5 years among instability patients, and beyond 10 years among aseptic loosening and/or wear patients. CONCLUSION:Mortality is elevated soon after revision TKA for infection and fracture. Mortality is lower than the general population after revision TKA for loosening and/or bearing wear but gets worse than the general population beyond the first postoperative decade.

BACKGROUND:Depression is common in the general population, and so it is likewise common among patients undergoing THA and TKA. Depression is associated with lower perioperative patient-reported outcomes and an increased risk of postoperative complications. Antidepressants are effective in managing symptoms of depression and may potentially contribute to better functional status and better clinical outcomes after THA and TKA. QUESTIONS/PURPOSES:We examined (1) whether perioperative depression is associated with all-cause revisions, revisions for aseptic loosening, revisions without infection, and periprosthetic joint infections (PJIs) in patients undergoing THA and TKA; and (2) whether perioperative antidepressant use reduces the risk of all-cause revisions, revisions for aseptic loosening, aseptic revisions, and PJIs in patients undergoing THA and TKA. METHODS:This was a retrospective study of adult patients (≥ 18 years) who underwent 20,112 primary and revision THAs and TKAs from January 1, 2002, through December 31, 2009, at a large US tertiary care hospital. Data on patient and surgery characteristics and outcomes (dates and types of revisions, death) were ascertained through the institutional joint registry. Perioperative antidepressant use was assessed by searching the daily medication administration records beginning at admission and ending at discharge. A diagnosis of depression was present in 4466 (22%), and antidepressants were administered at the time of 5077 (25%) surgical procedures. Multivariable Cox proportional hazard models were used to estimate associations between antidepressant use and the risk of all-cause revisions, revisions for aseptic loosening, aseptic revisions, and PJIs. RESULTS:Depression was associated with an increased risk of all-cause revisions (hazard ratio [HR], 1.73; 95% confidence interval [CI], 1.42-2.02; p < 0.001) and PJIs (HR, 2.23; 95% CI, 1.53-3.17; p < 0.001). Overall, perioperative antidepressant use was not associated with the risk of revision or PJI, but selective serotonin reuptake inhibitor (SSRI) users had a lower risk of all-cause revisions (HR, 0.77; 95% CI, 0.61-0.96; p = 0.001) and aseptic revisions (HR, 0.72; 95% CI, 0.56-0.93; p = 0.013). CONCLUSIONS:The presence of a depression diagnosis confers an increased risk of revision and PJI among patients undergoing THA and TKA, yet the risk is lower within the subset of patients who received SSRIs during the perioperative period. Future longitudinal studies with detailed antidepressant medication histories are warranted to better understand the potential biologic effects of SSRI on the risk of revision in patients undergoing THA and TKA. LEVEL OF EVIDENCE:Level III, therapeutic study.