Complication rates following reverse and anatomic shoulder replacement in treatment of glenohumeral arthritis: a 10-year Medicare review study.

BACKGROUND: We sought to compare the complication rates after anatomic total shoulder arthroplasty (aTSA) and reverse shoulder arthroplasty (RSA) for primary glenohumeral arthritis in a Medicare population. METHODS: Patients who underwent a shoulder arthroplasty were identified from the 5% subset of Medicare parts A/B between 2009 and 2019. Patients with less than 1-year follow-up were excluded. A total of 8846 patients with a diagnosis of glenohumeral arthritis were then subdivided into those who received aTSA (5935 patients) and RSA (2911 patients). A multivariate Cox regression analysis was then performed comparing complication rates at 3 months, 6 months, 1 year, 2 years, and 5 years. RESULTS: Statistically significant increased rates of instability (hazard ratio [HR] = 1.46), fracture of the scapula (HR = 7.76), infections (HR = 1.45), early revision (HR = 1.79), and all complications (HR = 1.32) were seen in the RSA group. There was no significant difference in revision rate at 5 years between the 2 groups. There was no difference in patient characteristics or comorbid conditions (smoking status, diabetes, Charlson score, etc.) or hospital characteristics (location, teaching status, public vs. private, etc.) between the 2 groups. CONCLUSION: An increased rate of early complications was observed with the use of RSA compared with aTSA for the treatment of primary glenohumeral arthritis, including instability, scapula fracture, infection, and all cause complication. No difference in revision rate between RSA and aTSA at 5 years was observed.

Strikingly High Rates of Periprosthetic Joint Infection Following Revision Surgery for Periprosthetic Fractures Regardless of Surgery Timing.

BACKGROUND: Periprosthetic fractures following total hip arthroplasty (THA) often occur in the early postoperative period. Recent data has indicated that early revisions are associated with higher complication rates, particularly periprosthetic joint infection (PJI). The purpose of this study was to assess the effect of timing of periprosthetic fracture surgery on complication rates. We hypothesized that complication rates would be significantly higher in revision surgeries performed within 3 months of the index THA. METHODS: The Medicare Part A claims database was queried from 2010 to 2017 to identify patients who underwent surgery for a periprosthetic fracture following primary THA. Patients were divided based on time between index and revision surgeries: <1, 1 to 2, 2 to 3, 3 to 6, 6 to 9, 9 to 12, and >12 months. Complication rates were compared between groups using multivariate analyses to adjust for demographics, comorbidities, and types of revision surgery. RESULTS: Of 492,340 THAs identified, 4,368 (0.9%) had a subsequent periprosthetic fracture requiring surgery: 1,725 (39.4%) at <1 month, 693 (15.9%) at 1 to 2 months, 202 (4.6%) at 2 to 3 months, 250 (5.7%) at 3 to 6 months, 134 (3.1%) at 6 to 9 months, 85 (19.4%) at 9 to12 months, and 1,279 (29.3%) at >12 months. The risk of PJI was 11.0% in the <1 month group, 11.1% at 1 to 2 months, 7.9% at 2 to 3 months, 6.8% at 3 to 6 months, 8.2% at 6 to 9 months, 9.4% at 9 to 12 months, and 8.5% at >12 months (P = .12). Adjusting for confounding factors, risk of PJI following periprosthetic fracture surgery was similar regardless of timing (P > .05). Rates of subsequent dislocation and aseptic loosening were also similar regardless of timing. CONCLUSIONS: The risk of PJI following repeat surgery for a periprosthetic fracture was strikingly high regardless of timing (6.8 to 11.1%), underscoring the high-risk of complications.

Incidence of Instability Following Primary Total Hip Arthroplasty Continues to Decline in the Medicare Population.

BACKGROUND: Instability has been the primary cause of failure following primary total hip arthroplasty (THA) leading to revision hip surgery. The purpose of this study was to determine if instability rates have further declined following advances in primary THA, including dual mobility articulations, direct anterior approaches, advanced technologies, and improved knowledge of the hip-spine relationships. METHODS: Using the 5% Medicare Part B claims data from 1999 to 2019, we identified 81,573 patients who underwent primary THA for osteoarthritis. Patients who experienced instability at 3 months, 6 months, 1 year, and 2 years were identified. Multivariate cox regression analyses evaluated the effect of patient and procedure characteristics on the risk of instability. RESULTS: Instability at 1 year following primary THA declined from approximately 4% in 2000 to 2.3% in 2010 and 1.6% in 2018. The leading cause of revision surgery was infection (18.6%), followed by periprosthetic fracture (14%), mechanical loosening (11.5%), and instability (9.4%). High-risk groups for instability continue to include increased age, higher Charlson index, obesity, lumbar spine pathology, and neurocognitive disorders. CONCLUSION: Instability is no longer the leading etiology of failure following primary THA with a decline of approximately 40% over the past decade. Infection, periprosthetic fracture, mechanical loosening, and then instability are now the leading causes of failure. Multiple factors may play a role in the decline of instability, including increased use of dual mobility articulations, direct anterior approaches, improved knowledge of the hip-spine relationships, and use of advanced technologies.

Manipulation Following Primary Total Knee Arthroplasty is Associated With Increased Rates of Infection and Revision.

BACKGROUND: Stiffness following total knee arthroplasty (TKA) is a disabling complication and manipulation under anesthesia (MUA) is often performed as an early intervention. Few studies have focused on the revision risk, infection risk, demographics, and clinical outcomes in Medicare patients undergoing MUA following primary TKA. METHODS: We reviewed 142,440 patients who had primary TKA from a national database and identified 3,652 patients (2.6%) who underwent MUA. Patient demographics and comorbid conditions were evaluated to identify risk factors. Incidence of revision and periprosthetic joint infection (PJI) at 1-, 2-, and 5-year time points in a cohort of MUA patients was compared to patients who did not undergo MUA. Multivariate Cox regressions were used for statistical analyses. RESULTS: The incidence of MUA was higher in Black versus White individuals (4.1 versus 2.5%, P < .001). Revision risk was significantly greater in the MUA group at 1-, 2-, and 5-year time points with a hazard ratio (HR) of, 3.81, 3.90, and 3.22 respectively, P < .001. One- and 2-year revision risk was significantly greater when MUA occurred at 6 to 12 months post-TKA when compared to <3 months, P < .05. Risk of PJI was significantly greater in the MUA group with a HR of 2.2, 2.2, and 2.1 at 1, 2, and 5 years, respectively P < .001. CONCLUSION: The incidence of MUA was 2.6%. There was an increased incidence of revision surgery and PJI in patients undergoing MUA. Patients at increased risk for stiffness following TKA should be closely monitored and treated with early intervention to minimize risk of poor outcomes.

Association Between Bio-Fermentation Derived Hyaluronic Acid and Healthcare Costs Following Knee Arthroplasty.

Background: Limiting access to intra-articular knee injections, including hyaluronic acid (HA), has been advocated as a cost-containment measure in the treatment of knee osteoarthritis. The association between presurgical injections and post-surgical complications such as early periprosthetic joint infection and revision remained to be investigated. This study evaluated pre- and post-surgical costs and rates of post-surgical complications in knee arthroplasty (KA) patients with or without prior HA use. Methods: Commercial and Medicare Supplemental Claims Data (IBM MarketScan Research Databases) from January 1, 2012 to December 31, 2018 were used to identify unilateral KA patients. Those who completed a course of bio-fermentation derived HA (Bio-HA) as the first-line HA therapy comprised of the test group (n = 4091), while the control group did not use HA prior to KA (n = 118,659). Using multivariable regression with propensity score (PS) weighting, overall healthcare costs, readmission rates, and revision rates were assessed at six months following KA. Results: Healthcare costs following KA were significantly lower for the Bio-HA group ($10,021 ± $22,796) than No HA group ($12,724 ± $32,966; PS p < 0.001). Bio-HA patients had lower readmission rates (8.9% vs 14.0%; PS p < 0.001) and inpatient costs per readmitted patient ($43,846 ± $50,648 vs $50,533 ± $66,150; PS p = 0.005). There were no differences in revision rate for any reason (Bio-HA: 0.78% vs No HA: 0.67%; PS p = 0.361) and with PJI (Bio-HA: 0.42% vs No HA: 0.33%; PS p = 0.192). Costs in the six months up to and including the KA were similar for both groups (Bio-HA: $49,759 ± $40,363 vs No HA: $50,532 ± $43,183; PS p = 0.293). Conclusion: Bio-HA use prior to knee arthroplasty did not appear to increase overall healthcare costs in the six months before and after surgery. Allowing access to HA injections provides a non-surgical therapeutic option without increasing cost or risk of post-surgical complications.

Robotic-Arm Assisted Total Knee Arthroplasty: Cost Savings Demonstrated at One Year.

Purpose: Robotic-arm assisted total knee arthroplasty (RATKA) has the potential to enhance radiographic, clinical, and patient-reported outcomes. The purpose of this study was to compare resource utilization, episode-of-care (EOC) costs, readmissions, and complications of robotic-arm assisted total knee arthroplasty (RATKA) and manual TKA (MTKA). Methods: TKA procedures were identified from a private payer claims database. RATKA procedures required both a robotic arm-assisted procedure code and a 60-day pre-operative computed tomography scan. Propensity score matching (1:5 RATKA to MTKA) was performed, based on various patient characteristics and comorbidities. After matching, 4452 patients (742 RATKA and 3710 MTKA) were analyzed for 90-day and one-year EOC costs, index TKA costs, lengths of stay (LOS), discharge statuses, rehabilitation utilizations, as well as 90-day and one-year readmissions- and knee-related complications. Results: RATKA patients had shorter LOS (mean 1.56 versus 1.91 days; p < 0.001), lower index costs by $1762 ($32,747 versus $34,509; p = 0.003), and higher discharges to home rates (51.8 versus 47.8%; p = 0.049) than MTKA patients. RATKA patients had less 90-day (68.5 versus 72.0%; p = 0.048) and one-year (70.8 versus 75.0%; p = 0.016) home health utilizations. The RATKA cohort had lower 90-day ($39,260 versus $41,458; p = 0.001) and one-year ($51,462 versus $54,171; p = 0.011) EOC costs. No significant differences in readmission and overall complication rates were observed (p > 0.05). Conclusion: RATKA was associated with lower index costs and EOC costs at both 90 days and one year. These patients had shorter LOS, were discharged home more frequently, and used less home health services. Cost savings were demonstrated for RATKA beyond the 90-day period with an increase in savings between 90-day and one-year time points. These data may be of importance to payers and providers interested in the longer-term value of RATKA.

Changes in prescription pain medication and intra-articular corticosteroid utilization after intra-articular bio-fermentation derived hyaluronic acid use in patients undergoing multimodal pain management.

BACKGROUND: Multiple interventions may be used to treat symptomatic knee osteoarthritis (OA), but concerns have been raised about the safety and efficacy of some therapies. Clinical trials have shown that hyaluronic acid (HA) can provide pain relief up to 6 months and possibly to 12 months, while real-world data has shown that pain medication and intra-articular corticosteroid (CS) injection utilization are reduced within 6 months after HA. OBJECTIVE: To examine changes in prescription pain medication and CS utilization during 1 year after multimodal therapy that included high molecular weight, bio-fermentation derived HA (Bio-HA) use for knee OA. METHODS: Commercial and Medicare Supplemental claims data (IBM MarketScan Research Databases) (1 January 2012, through 31 December 2018) was used to identify unilateral Bio-HA patients using multimodal therapy (any combination of CS injection, opioids, and non-opioid pain medication). Monthly therapy utilization was compared in the 12 months after Bio-HA therapy initiation to the 4-month intra-multimodal period. RESULTS: A total of 13,999 patients underwent Bio-HA therapy with concurrent multimodal therapy. The number of filled opioid prescriptions decreased from 2,913.0/month to 2,861.5/month after Bio-HA, with a reduction in mean monthly prescriptions from 0.60 to 0.43 per user (p < 0.001). A number of opioid days supplied also decreased from 48,914/month to 39,730/month, with a decrease from 10.1/month to 6.0/month per user (p < 0.001). Bio-HA patients had prescription pain medication-free days for 71% of the time post-multimodal period compared to 53% during the intra-multimodal period (p < 0.001). The proportion of patients with CS injections after Bio-HA decreased from 53.8% to 29.6% (p < 0.001). Total monthly CS injections decreased from 2,292 to 663. CONCLUSIONS: Our data suggest that high molecular weight Bio-HA, as part of multimodal therapy, may be effective in providing longer-term pain relief with the reduction in pain therapy (CS injections and opioids) and increase in prescription pain medication-free days.

Intra-Articular Corticosteroid or Hyaluronic Acid Injections Are Not Associated with Periprosthetic Joint Infection Risk following Total Knee Arthroplasty.

This study evaluated whether the preoperative use and timing of the use of hyaluronic acid (HA) and/or corticosteroid (CS) injections were associated with an increased risk of periprosthetic joint infections (PJIs) following primary total knee arthroplasty (TKA). We tested the hypothesis that preoperative injection of HA or CS within 3 months prior to primary TKA was associated with an increased risk of PJI by specifically evaluating the association between PJI risk and (1) injection type; (2) timing; (3) patient demographic factors; and (4) surgery-related factors, such as surgeon injection volume, knee arthroscopy (pre- and postoperative), and hospital length of stay. The 5% Medicare part B claims database was queried for patients who received CS and/or HA injections. Cox proportional hazards regressions evaluated the risk of PJIs after TKA, adjusting for patient and clinical factors, as well as propensity scores. The unadjusted incidence of PJI at 2-year post-TKA was 0.75% for the CS group, 0.89% for the HA group, 0.96% for both CS and HA group, and 0.75% for those who did not use HA or CS in the 12 months before TKA. For patients who used HA and/or CS within 3 months prior to TKA, the unadjusted incidence of PJI at 2-year post-TKA was 0.75% for the CS group, 1.07% for the HA group, and 1.00% for both CS and HA group, compared with 0.77% for those who did not use HA or CS. The number of injections performed per year was inconsistently associated with PJI risk. Overall, we found that intra-articular injections given within the 4-month period prior to TKA were not associated with elevated PJI risk (evaluated at 1, 3, 12, and 24 months after the index TKA) within the elderly Medicare patient population.

Revision Surgery for Instability After Total Hip Arthroplasty: Does Timing Matter?

BACKGROUND: Instability is a common reason for revision surgery after total hip arthroplasty (THA). Recent studies suggest that revisions performed in the early postoperative period are associated with higher complication rates. The purpose of this study is to assess the effect of timing of revision for instability on subsequent complication rates. METHODS: The Medicare Part A claims database was queried from 2010 to 2017 to identify revision THAs for instability. Patients were divided based on time between index and revision surgeries: <1, 1-2, 2-3, 3-6, 6-9, 9-12, and >12 months. Complication rates were compared between groups using multivariate analyses to adjust for demographics and comorbidities. RESULTS: Of 445,499 THAs identified, 9298 (2.1%) underwent revision for instability. Revision THA within 3 months had the highest rate of periprosthetic joint infection (PJI): 14.7% at <1 month, 12.7% at 1-2 months, and 10.6% at 2-3 months vs 6.9% at >12 months (P < .001). Adjusting for confounding factors, PJI risk remained elevated at earlier periods: <1 month (adjusted odds ratio [aOR]: 1.84, 95% confidence interval [CI]: 1.51-2.23, P < .001), 1-2 months (aOR: 1.45, 95% CI: 1.16-1.82, P = .001), 2-3 months (aOR: 1.35, 95% CI: 1.02-1.78, P = .036). However, revisions performed within 9 months of index surgery had lower rates of subsequent instability than revisions performed >12 months (aOR: 0.67-0.85, P < .050), which may be due to lower rates of acetabular revision and higher rates of head-liner exchange in this later group. CONCLUSION: When dislocation occurs in the early postoperative period, delaying revision surgery beyond 3 months from the index procedure may be warranted to reduce risk of PJI.

Knee Osteoarthritis Treatment Costs in the Medicare Patient Population.

BACKGROUND: Several nonoperative options have been recommended for the treatment of knee osteoarthritis (OA), with varying degrees of evidence. Adhering to the American Academy of Orthopaedic Surgeons clinical practice guidelines has been suggested to decrease direct treatment costs by 45% in the year before knee arthroplasty, but this does not consider the cost of the entire episode of care, including the cost of surgery and postsurgery care. OBJECTIVES: To analyze the total treatment costs after a diagnosis of knee OA, as well as the proportion of arthroplasty interventions as part of the total knee OA-related costs, and whether the total costs differed for patients who received intra-articular hyaluronic acid and/or had knee arthroplasty. METHODS: We identified patients newly diagnosed with knee OA using the 5% Medicare data sample from January 2010 to December 2015. Patients were excluded if they were aged <65 years, had incomplete claim history, did not reside in any of the 50 states, had claim history <12 months before knee OA diagnosis, or did not enroll in Medicare Part A and Part B. The study analyzed knee OA-related costs from a payer perspective in terms of reimbursements provided by Medicare, as well as the time from the diagnosis of knee OA to knee arthroplasty for patients who had knee arthroplasty, and the time from the first hyaluronic acid injection to knee arthroplasty for those who received the injection. We compared patients who received hyaluronic acid and those who did not receive hyaluronic acid injections. Patients who received hyaluronic acid injection who subsequently had knee arthroplasty were also compared with those who did not have subsequent knee arthroplasty. RESULTS: Of the 275,256 patients with knee OA, 45,801 (16.6%) received a hyaluronic acid injection and 35,465 (12.9%) had knee arthroplasty during the study period. The median time to knee arthroplasty was 16.4 months for patients who received hyaluronic acid versus 5.7 months for those who did not receive hyaluronic acid. Non-arthroplasty-related therapies and knee arthroplasty accounted for similar proportions of knee OA-related costs, with hyaluronic acid injection comprising 5.6% of the total knee OA-related costs. For patients who received hyaluronic acid injections and subsequently had knee arthroplasty, hyaluronic acid injection contributed 1.8% of the knee OA-related costs versus 76.6% of the cost from knee arthroplasty. Patients who received hyaluronic acid injections and did not have knee arthroplasty incurred less than 10% of the knee OA-related costs that patients who had surgery incurred. CONCLUSION: Although limiting hyaluronic acid use may reduce the knee OA-related costs, in this study hyaluronic acid injection only comprised a small fraction of the overall costs related to knee OA. Among patients who had knee arthroplasty, those who received treatment with hyaluronic acid had surgery delayed by a median of 10.7 months and associated costs for a significant period. The ability to delay or avoid knee arthroplasty altogether can have a substantial impact on healthcare costs.

Reoperation Risk After Total Elbow Arthroplasty Versus Open Reduction Internal Fixation for Distal Humerus Fractures in Elderly Patients.

OBJECTIVE: To compare reoperation risk after total elbow arthroplasty (TEA) and open reduction internal fixation (ORIF) for intra-articular distal humerus fractures in elderly patients. DESIGN: Retrospective comparative. SETTING: Five percent Medicare Part B claims database. PATIENTS: Patients older than 65 years of age with closed distal humerus fractures undergoing TEA or ORIF from 1996 to 2016. INTERVENTION: TEA and ORIF. MAIN OUTCOME MEASURE: Reoperation risk based on multivariate Cox proportional hazards modeling. RESULTS: A total of 142 TEA and 522 ORIF cases were identified. TEA patients had a greater age and Charlson Comorbidity Index , as well as a higher prevalence of rheumatoid arthritis and osteoporosis than ORIF patients (P < 0.05). Although reoperation risk was lower for TEA than that for ORIF within the entire cohort (11.3% vs. 25.1%; hazard ratio = 0.49; P = 0.014), no significant difference was found for TEA and ORIF performed between 2006 and 2016 (12.6% vs. 18.4%; hazard ratio = 0.73; P = 0.380). The death rate was 65.5% in the TEA group at 3.6 years and 55.7% in the ORIF group at 4.9 years. CONCLUSIONS: TEA was associated with a decreased reoperation risk compared with ORIF, although this difference did not exist for more recent procedures after popularization of the locking plate technology and half of the reoperations after ORIF were for instrumentation removal. The high death rate within several years of the index procedure may contribute to the low TEA revision rate beyond the short-term when following patients into the medium and long term. Further study comparing TEA and locked plating using prospective, randomized data with long-term follow-up and functional outcomes is warranted. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Knee OA cost comparison for hyaluronic acid and knee arthroplasty.

BACKGROUND: Limiting treatment to those recommended by the American Academy of Orthopaedic Surgeon Clinical Practice Guidelines has been suggested to decrease costs by 45% in the year prior to total knee arthroplasty, but this only focuses on expenditures leading up to, but not including, the surgery and not the entire episode of care. We evaluated the treatment costs following knee osteoarthritis (OA) diagnosis and determined whether these are different for patients who use intra-articular hyaluronic acid (HA) and/or knee arthroplasty. METHODS: Claims data from a large commercial database containing de-identified data of more than 100 million patients with continuous coverage from 2012 to 2016 was used to evaluate the cumulative cost of care for over 2 million de-identified members with knee OA over a 4.5-year period between 2011 and 2015. Median cumulative costs were then stratified for patients with or without HA and/or knee arthroplasty. RESULTS: Knee OA treatment costs for 1,567,024 patients over the 4.5-year period was $6.60 billion (mean $4210/patient) as calculated by the authors. HA and knee arthroplasty accounted for 3.0 and 61.5% of the overall costs, respectively. For patients who underwent knee arthroplasty, a spike in median costs occurred sooner for patients without HA use (around the 5- to 6-month time point) compared to patients treated with HA (around the 16- to 17-month time point). CONCLUSIONS: Non-arthroplasty therapies, as calculated by the authors, accounted for about one third of the costs in treating knee OA in our cohort. Although some have theorized that limiting the use of HA may reduce the costs of OA treatment, HA only comprised a small fraction (3%) of the overall costs. Among patients who underwent knee arthroplasty, those treated with HA experienced elevated costs from the surgery later than those without HA, which reflects their longer time to undergoing knee arthroplasty. The ability to delay or avoid knee arthroplasty altogether can have a substantial impact on the cost to the healthcare system.

Incidence, Severity, and Characterization of Phytophthora Foot Rot of Citrus in Texas and Implications for Disease Management.

Phytophthora-induced foot rot, also known as gummosis, is an important disease affecting citrus production worldwide. In Texas, the third-largest citrus-producing state in the United States, limited information is available on the etiology and epidemiology of foot rot in commercial orchards. This study comprises a survey of foot rot incidence and severity in Texas and the characterization of Phytophthora isolates associated with the disease. Surveys in 2015 and 2017 of 30 orchards in the Lower Rio Grande Valley (LRGV) region where commercial citrus production is concentrated in the state revealed that foot rot occurred in 97% of the orchards assessed. Overall, foot rot symptoms were observed on 33.7% of the trees evaluated and the disease severity index in the region was rated at 14.2 and 16.5% in 2015 and 2017, respectively. Lesions were mostly present on the scion, while the rootstock (sour orange) was not affected. Phytophthora nicotianae was the only Phytophthora sp. isolated from the surveyed orchards and from five additional residential sites on the Texas Coastal Bend (TCB). Sporangia and chlamydospores from 34 representative LRGV isolates of P. nicotianae were larger than those of TCB isolates. In both LRGV and TCB, A1 and A2 mating types were present in the same location, albeit the A2 mating type was more prevalent. All isolates were sensitive to mefenoxam (50% inhibition in the presence of mefenoxam [EC50] < 0.5 µg/ml), except for one TCB isolate (EC50 = 143.6 µg/ml). Our research indicates that treatment for Phytophthora foot rot in the region is necessary and, although mefenoxam is still useful, alternating chemistries for resistance management are required.

Corrosion Concerns? Trends in Metal-on-Polyethylene Total Hip Arthroplasty Revision Rates and Comparisons Against Ceramic-on-Polyethylene up to 10 Years of Follow-Up.

BACKGROUND: We compared the revision risk between metal-on-polyethylene (MOP) and ceramic-on-polyethylene (COP) total hip arthroplasty patients and evaluated temporal changes in short-term revision risks for MOP patients. METHODS: Primary MOP (n = 9480) and COP (n = 3620) total hip arthroplasties were evaluated from the Medicare data set (October 2005 to December 2015) for revision risk, with up to 10 years of follow-up using multivariate analysis. Temporal change in the short-term revision risk for MOP was evaluated (log-rank and Wilcoxon tests). RESULTS: Revision incidence was 3.8% for COP and 4.3% for MOP. MOP short-term revision risk did not change over time (P ≥ .844 at 1 year and .627 at 2 years). Dislocation was the most common reason for revision (MOP: 23.5%; COP: 24.8%). Overall adjusted revision risks were not different between MOP and COP up to 10 years of follow-up (P ≥ .181). CONCLUSIONS: Concerns with corrosion for metal heads do not appear to result in significantly elevated revision risk for MOP at up to 10 years. Corrosion does not appear as a primary reason for revision compared to other mechanisms.

Complications and Readmission Incidence Following Total Hip Arthroplasty in Patients Who Have End-Stage Renal Failure.

BACKGROUND: The number of patients who have end-stage renal disease undergoing primary total hip arthroplasty (THA) has increased over the past decade. The purpose of this study is to evaluate mortality, complications, and 90-day readmission incidences in patients who have end-stage renal disease undergoing THA. METHODS: Patients who had a primary THA between January 1, 2007, and December 31, 2016, were identified from the 5% Medicare database. A total of 55,297 THA patients were stratified into 3 groups: renal dialysis (without transplant), renal transplant, and those without such renal problems. Risk of readmissions, dislocations, periprosthetic joint infections (PJIs), venous thromboembolic diseases, and mortalities up to 5 years following primary THA was compared. Multivariate Cox regression analyses were used to evaluate the effect of patient and hospital characteristics on the adjusted complication risks. RESULTS: Mortalities at 5 years was 62.6% in the renal dialysis group, 37.3% in the renal transplant group, compared to 15.0% in the nonrenal group. Dislocations (7.6%) and PJIs (7%) were significantly higher in the dialysis group (P < .001). No significant differences in venous thromboembolic diseases (all timepoints) and revisions (all timepoints except at 90 days) between the renal groups were observed. The 90-day readmission risks were significantly greater in both the dialysis (55%) and transplant (43%) groups compared to the nonrenal cohort (30%) (P < .001). CONCLUSION: Renal dialysis patients undergoing THA are at increased risk of PJIs (7%), dislocations (7.6%), revisions, and mortalities at 90 days compared to transplant and nonrenal patients. Both dialysis and transplant patients are high-risk groups with significantly increased 90-day readmission incidences of 55% and 43%, respectively, which makes their inclusion into a bundled payment model challenging.

Unicondylar Knee Arthroplasty Has Fewer Complications but Higher Revision Rates Than Total Knee Arthroplasty in a Study of Large United States Databases.

BACKGROUND: Unicondylar knee arthroplasty (UKA) has superior functional outcomes compared to total knee arthroplasty (TKA) with good mid-term and long-term survival data from high-volume institutions. We sought to quantify the risk of complications, re-operation/revision, hospital re-admission for any reason, and mortality of knee arthroplasty patients in the US patient population using 2 large databases. METHODS: UKA and TKA patients who were identified in the 2002-2011, 5% sample of Medicare data and 2004-2012 (June) MarketScan Commercial and Medicare Supplemental Databases were followed to evaluate the risk of complications, hospital re-admission for any reason, and mortality within 90 days of surgery. Survival probability defined by re-operation was calculated using the Kaplan-Meier method at 0.5, 2, 5, 7, and up to 10 years post-operatively. RESULTS: Compared to UKA, complication rates for TKA patients were significantly higher, including wound complication, pulmonary embolism, stiffness, peri-prosthetic joint infection, myocardial infarction, re-admission, and death. Age was found to be a significant risk factor (P < .05) for all complications in the Medicare cohort, except stiffness (P = .839), and all complications in the MarketScan cohort, except re-admission (P = .418), whereas gender had a variable effect on complications based on age. Survivorship of UKA was lower than TKA at all time points. Additionally, younger age adversely affected implant survival. By 7 years post-surgery, UKA survivorship in the Medicare and MarketScan cohorts was 80.9% and 74.4%, respectively. In contrast, TKA survivorship for the same cohorts was 95.7% and 91.9% by the same time point. CONCLUSION: Patients undergoing UKA have fewer post-operative complications and re-admissions than those undergoing TKA. However, patients undergoing UKA have a higher rate of re-operation and revision at up to 10 years of follow-up. It appears that age, as well as surgeon and hospital volume significantly impacts implant survivorship while gender does not have a relation. LEVEL OF EVIDENCE: Level III.

Cost-of-illness of knee osteoarthritis: potential cost savings by not undergoing arthroplasty within the first 2 years.

PURPOSE: Although knee arthroplasty (KA) is the largest source of hospitalization costs for knee osteoarthritis (OA), some studies have suggested reducing the use of "low-value" interventions, such as intra-articular hyaluronic acid (HA), to lower health care costs. However, those studies fail to consider that HA has demonstrated benefits in extending time to more costly KA or avoiding KA altogether. We evaluated 1) the overall knee OA costs (direct) within a 2-year period; 2) the relative contribution of HA and KA costs; 3) the direct cost savings from HA patients not undergoing KA. PATIENTS AND METHODS: Knee OA patients were identified from the Optum Clinformatics data set, which includes physician, facility, and pharmacy claims data from privately insured patients of all ages. Patients were stratified in the no HA, non-hylan G-F 20, and hylan G-F 20 cohorts. The cumulative costs (payer perspective) were evaluated for all knee OA-related claims (adjusted to Consumer Price Index Jan 2017$) for patients who had at least 2 years follow-up. Costs were stratified into various clinical categories. RESULTS: The study cohort included 2,030,497 knee OA patients, of which 65,144 patients (3.2%) underwent KA. The cost of treating knee OA within the 2-year follow-up period was estimated to be $4.99 billion (B). The majority of the costs (69%) were attributed to KA patients (3.2% of patients). In all, 15.9% of the HA patients underwent KA within 2 years, but HA only contributed 1.7% to the total costs for these patients. The remaining 84.1% of HA patients did not undergo KA, which saved an estimated total of $1.54B (average $20,740 per patient) or 83.9%, after accounting for their non-KA therapies. CONCLUSION: Our study estimated substantial cost savings through a large percentage of HA patients not undergoing KA. Although a fraction of patients moved on from their conservative therapy to undergo KA within the 2-year period, HA attributed to <2% of their total treatment costs.

Does Timing of Primary Total Hip Arthroplasty Prior to or After Lumbar Spine Fusion Have an Effect on Dislocation and Revision Rates?

BACKGROUND: Patients undergoing primary total hip arthroplasty (THA) following lumbar spine fusion have an increased incidence of dislocation compared to those without prior lumbar fusion. The purpose of this study is to determine if timing of THA prior to or after lumbar fusion would have an effect on dislocation and revision incidence in patients with both hip and lumbar spine pathology. METHODS: One hundred percent Medicare inpatient claims data from 2005 to 2015 were used to compare dislocation and revision risks in patients with primary THA with pre-existing lumbar spine fusion vs THA with subsequent lumbar spine fusion within 1, 2, and 5 years after the index THA. A total of 42,300 patients met inclusion criteria, 28,668 patients of which underwent THA with pre-existing lumbar spinal fusion (LSF) and 13,632 patients who had prior THA and subsequent LSF. Patients who had THA first followed by LSF were further stratified based on the interval between index THA and subsequent LSF (1, 2, and 5 years), making 4 total groups for comparison. Multivariate cox regression analysis was performed adjusting for age, socioeconomic status, race, census region, gender, Charlson score, pre-existing conditions, discharge status, length of stay, and hospital characteristics. RESULTS: Patients with prior LSF undergoing THA had a 106% increased risk of dislocation compared to those with LSF done 5 years after THA (P < .001). Risk of revision THA was greater in the pre-existing LSF group by 43%, 41%, and 49% at 1, 2, and 5 years post THA compared to the groups with THA done first with subsequent LSF. Dislocation was the most common etiology for revision THA in all groups, but significantly higher in the prior LSF group (26.6%). CONCLUSION: Results of this study demonstrate that sequence of surgical intervention for concomitant lumbar and hip pathology requiring LSF and THA respectively significantly impacts the fate of the THA performed. Patients with prior LSF undergoing THA are at significantly higher risk of dislocation and subsequent revision compared to those with THA first followed by delayed LSF. LEVEL OF EVIDENCE: 3.

Risk Adjustment Is Necessary in Medicare Bundled Payment Models for Total Hip and Knee Arthroplasty.

BACKGROUND: Concerns exist that high-risk patients in alternative payment models may face difficulties with access to care without proper risk adjustment. The purpose of this study is to identify the effect of medical and orthopedic specific risk factors on the cost of a 90-day episode of care following total hip (THA) and knee arthroplasty (TKA). METHODS: We queried the Medicare 5% Limited Data Set for all patients undergoing primary THA and TKA from 2010 to 2014. To evaluate the cost of an episode of care, we calculated all claims for 90 days following surgery. Multivariate analysis was performed to quantify the added episode-of-care costs for demographic variables, geography, medical comorbidities, and orthopedic specific risk factors. RESULTS: Of the 58,809 TKA patients, the median 90-day Medicare costs was $23,800 (interquartile range, $18,900-$32,300), while the median of the 27,293 THA patients was $24,000 (interquartile range, $18,500-$33,900). Independent risk factors (all P < .05) resulting in at least a 10% increase in episode-of-care costs following TKA included malnutrition, age over 85, male gender, pulmonary disorder, failed internal fixation, Northeast region, lower socioeconomic status, neurologic disorder, and rheumatoid arthritis. Independent risk factors (all P < .05) resulting in at least a 10% increase in episode-of-care costs following THA included malnutrition, male gender, age over 85, failed internal fixation, hip dysplasia, Northeast region, neurologic disorder, lower socioeconomic status, conversion THA, avascular necrosis, and depression. CONCLUSION: Certain comorbidities and orthopedic risk factors increase 90-day episode-of-care costs in the Medicare population. The current lack of proper risk stratification could be a powerful driver of decreased access to care for our most medically challenged members of society.

Risk of Osteoporotic Fracture After Steroid Injections in Patients With Medicare.

To further evaluate the relationship between steroid injections and osteoporotic fracture risk, we analyzed Medicare administrative claims data on both large-joint steroid injections (LJSIs) into knee and hip and transforaminal steroid injections (TSIs), as well as osteoporotic hip and wrist fractures. Our hypothesis was that a systemic effect of steroid injections would increase fracture risk in all skeletal locations regardless of injection site, whereas a local effect would produce a disproportionate increased risk of spine fracture with spine injection. Patients treated with an LJSI, a TSI, or an epidural steroid injection (ESI) were identified from 5% Medicare claims data. Patients under age 65 years and patients with prior osteoporotic fracture were excluded. Analyses were performed to determine fracture risk (adjusted hazard ratio) for each type of injection. Analysis of the Medicare data revealed that ESIs were associated with decreased osteoporotic spine fracture risk, but the effect was small and might not be clinically relevant. ESIs did not influence osteoporotic hip or wrist fracture risk, but LJSIs reduced the risk.