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Background The Comprehensive Care for Joint Replacement model aims to support more efficient care for patients. We examined the impact of patient and surgical characteristics, post-acute care, and clinical outcomes on episode of care (EOC) costs in patients undergoing hip arthroplasty for all diagnoses. Methods We retrospectively collected data from a large database of patients undergoing hip arthroplasty for oncologic and nononcologic diagnoses between 2014 and 2017. We compared EOC costs and outcomes between the 2 groups using Student’s t-tests. We estimated the association between an oncologic-associated procedure and EOC costs from a multiple regression analysis. Results There were 2122 total patients included: 1993 in the nononcologic group and 129 in the oncologic group. The length of stay was significantly greater in the oncologic group (7.2 vs 4.2 days, P = .00). In the post-acute period, a greater proportion of oncologic patients was readmitted (29% vs 14%, P = .05) and discharged to skilled nursing (93% vs 51%, P = .00). Index hospitalization costs (mean difference [MD] $1561, P = .05), skilled nursing costs (MD $5932, P = .001), and total EOC costs (MD $20,012, P = .00) were all greater in the oncologic group. Along with increasing age and fracture diagnosis, an oncologic diagnosis is independently associated with greater EOC costs from a multivariate analysis (β = 16,163 ± 2258, P = .00, r2 = 29%). Conclusion Comprehensive Care for Joint Replacement should incorporate risk adjustment for oncologic disease because hip arthroplasty for an oncologic diagnosis is associated with worse outcomes and greater costs than in the general population.

Psoriasis is a dermatologic condition characterized by erythematous plaques that may increase wound complications and deep infections following total knee arthroplasty (TKA). There is a paucity of evidence concerning the association of this disease and complications after TKA. This study aimed to determine if patients who have psoriasis vs non-psoriatic patients have differences in demographics and various comorbidities as well as post-operative infections, specifically the following: (1) wound complications; (2) cellulitic episodes; and (3) deep surgical site infections (SSIs).We identified 10,727 patients undergoing primary TKA utilizing an institutional database between January 1, 2017 and April 1, 2019. A total of 133 patients who had psoriasis (1.2%) were identified using International Classification of Diseases, Tenth Revision codes and compared to non-psoriatic patients. The rate of wound complications, cellulitic episodes, and deep SSIs were determined. After controlling for age and various comorbidities, multivariate analyses were performed to identify the associated risks for post-operative infections.Psoriasis patients showed an increased associated risk of deep SSIs (3.8%) compared to non-psoriasis patients (1.2%, P = .023). Multivariate analyses demonstrated a significant associated risk of deep SSIs (odds ratio 7.04, 95% confidence interval 2.38-20.9, P.001) and wound complications (odds ratio 4.44, 95% confidence interval 1.02-19.2, P = .047).Psoriasis is an inflammatory dermatologic condition that warrants increased pre-operative counseling, shared decision-making, and infectious precautions in the TKA population given the increased risk of wound complications and deep SSIs. Increased vigilance is required given the coexistence of certain comorbidities with this population, including depression, substance use disorder, smoking history, gastroesophageal reflux disease, and inflammatory bowel disease.

To facilitate the interpretation of numerical patient-reported outcome measure (PROM) scales, concepts such as the patient acceptable symptom state (PASS) have been introduced. Currently, no PASS thresholds have been established for the Knee injury and Osteoarthritis Outcome Score (KOOS) after total knee arthroplasty. The aims of the current study were to define PASS thresholds for the KOOS subscales and several other generic and knee-specific PROMs at 1 and 3 years after total knee arthroplasty using data from an international, multicenter clinical outcome study of a modern, well-performing implant system.The study cohort consisted of 499 patients undergoing total knee arthroplasty from an international, multicenter study. At 1 and 3 years after a total knee arthroplasty, patients completed the KOOS, EuroQoL 5-dimension 3-level (EQ-5D-3L), EuroQol visual analog scale (EQ-VAS), and numerical rating scales (NRS) for knee-related pain and satisfaction. PASS thresholds were calculated at each follow-up interval using 3 anchor-based approaches, using patient-reported satisfaction as the anchor.According to our satisfaction anchor, 302 (78.9%) of 383 responding patients were satisfied at 1 year, and 242 (80.4%) of 301 responding patients were satisfied at 3 years. PASS thresholds were 84.5 points at 1 year and 87.5 points at 3 years for KOOS pain, 80.5 points at 1 year and 84.0 points at 3 years for KOOS symptoms, 83.0 points at 1 year and 87.5 points at 3 years for KOOS activities of daily living, 66.0 points at 1 year and 66.0 points at 3 years for KOOS quality of life, 83.0 points at 1 year and 90.5 points at 3 years for EQ-VAS, 0.80 point at 1 year and 0.80 point at 3 years for EQ-5D, and 1.8 points at 1 year and 1.8 points at 3 years for NRS pain.The current study is the first, to our knowledge, to propose PASS thresholds for the KOOS subscales at 1 and 3 years after total knee arthroplasty and contributes to PASS literature on other common PROMs. These findings will provide a useful reference for future total knee arthroplasty outcome studies and will help to determine what patients consider to be satisfactory operations.Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Since the first arthroplasty registries were established in the 1970s, they have become powerful tools in improving the efficiency of health care delivery and patient outcomes. As demonstrated over the past decades, registries can offer benefits not only to patients and surgeons but also to a variety of other stakeholders, such as hospitals, payers, and implant manufacturers. Registry data may be leveraged to address a variety of pressing concerns in the field of arthroplasty. These examples include the role of registries in (1) informing the financial aspects of an increasingly value-based payment system, (2) identifying best clinical practices, (3) improving the outcomes of individual health care providers, and (4) selecting new technologies through outlier detection and benchmarking. As registries continue to mature by improving data coverage and quality, they will play a central role in shaping the future of arthroplasty as well as orthopaedics in general.

BACKGROUND: Adverse local tissue reaction (ALTR) is not only a prominent cause of metal-on-metal (MoM) implant revision, but may also compromise the result of revision surgery. Patients treated with MoM arthroplasty and subsequently revised as a result of ALTR have been shown to experience worse patient-reported outcomes, inferior survivorship, and more complications when compared with patients receiving MoM implants who were revised for reasons other than ALTR. There is conflicting evidence as to whether the presence of symptoms is associated with ALTR in patients with MoM implants. Blood metal ions are associated with ALTR, but a consensus on appropriate thresholds associated with ALTR risk is lacking. QUESTIONS/PURPOSES: (1) Was the presence of symptoms as measured by patient-reported outcome measures associated with ALTR presence and severity as noted on metal artifact reduction sequence (MARS)-MRI in patients treated with one design of MoM THA or hip resurfacing arthroplasty (HRA)? (2) Could reliable thresholds for blood metal ion levels be determined that were associated with ALTR presence on MARS-MRI? METHODS: This retrospective study presents a secondary analysis of data drawn from a prospective, international, multicenter study of the recalled Articular Surface Replacement (ASR) hip system. This larger study aims to identify risk factors for revision and provide followup guidelines for the many unrevised ASR patients. A total of 1721 patients were enrolled from 16 centers in six countries after the device was recalled and are followed annually for 5 years. In the present analysis, data from the enrollment visit (mean time from index surgery, 7.5 years; SD 3.5 years) were considered. Only patients from two centers conducting MARS-MRI on all patients regardless of clinical presentation as a standard of care were included to avoid selection bias. A total of 327 unilateral patients fulfilled our inclusion criteria (90% of those eligible). The level of symptoms was systematically determined using the Harris hip score and a visual analog scale for pain, and whole blood metal ion levels were collected from all patients. MARS-MRIs were analyzed by a single reader for ALTR presence (Anderson classification), diameter, and synovial thickness. A validation series of 35 MARS-MRIs indicated excellent intrareader reproducibility of the evaluations (intraclass correlation = 0.82) and substantial agreement (κ coefficient = 0.64) was achieved between the MARS-MRI reader and a musculoskeletal radiologist with > 10 years of experience with MARS-MRI. Binary logistic regression was used to determine variables independently associated with ALTR. Receiver operator characteristic curves were used to determine sensitive and specific cut points for cobalt and chromium. RESULTS: After controlling for confounding variables, presence of symptoms was determined to be a risk factor for ALTR (odds ratio, 2.9; p = 0.007) in patients treated with ASR MoM THA. Moreover, among patients undergoing ASR MoM THA with ALTR, synovial thickness correlated with symptomaticity (p = 0.030). For patients undergoing ASR MoM HRA, we found no association between symptoms and ALTR prevalence or severity. A cobalt cutoff of 3.2 parts per billion (ppb) was associated with increased risk of ALTR (p < 0.001; sensitivity, 68%; specificity, 71%) in ASR MoM THA. In patients with ASR MoM HRA, a cobalt threshold of 2.9 ppb was indicative of ALTR (p < 0.001; sensitivity, 79%; specificity, 69%). CONCLUSIONS: The risk factors identified in the current study may be used to stratify patients receiving MoM implants in terms of ALTR risk. We found that symptoms are associated with an increased likelihood of ALTR presence in ASR MoM THA and that cobalt ion level is associated with ALTR in ASR MoM THA as well as ASR MoM HRA. Importantly, MoM HRA followup protocols that exempt asymptomatic patients from annual followup are not justified because asymptomatic patients are no less likely to have ALTR than symptomatic patients. Blood metal ion levels may reliably be used to screen patients undergoing MoM HRA. For patients undergoing MoM THA, a combination of symptom state and blood metal ion levels may be used to determine ALTR risk. LEVEL OF EVIDENCE: Level III, diagnostic study.

Background Currently, there are no universally accepted guidelines on when to obtain metal artifact reduction sequence magnetic resonance imaging (MARS-MRI) in metal-on-metal (MoM) hip resurfacing arthroplasty (HRA) patients. Our primary aims were to identify which patient and clinical factors are predictive of adverse local tissue reaction (ALTR) and create an algorithm for indicating MARS-MRI in patients with Articular Surface Replacement (ASR) HRA. The secondary aim was to compare our algorithm to existing guidelines on when to perform MARS-MRI in MoM HRA patients. Methods The study cohort consisted of 182 patients with unilateral ASR HRA from a prospective, multicenter study. Subjects received MARS-MRI at a mean of 7.8 years from surgery, regardless of symptoms. We determined which variables were predictive of ALTR and generated cutoffs for each variable. Finally, we created an algorithm to predict ALTR and indicate MARS-MRI in ASR HRA patients using these cutoffs and compared it to existing guidelines. Results We found high blood cobalt (Co) (odds ratio = 1.070; P = .011) and high blood chromium (Cr) (odds ratio = 1.162; P = .002) to be significant predictors of ALTR presence. Our algorithm using a blood Co cutoff of 1.15 ppb and a Cr cutoff of 1.09 ppb achieved 96.6% sensitivity and 35.3% specificity in predicting ALTR, which outperformed the existing guidelines. Conclusion Blood Co and Cr levels are predictive of ALTR in ASR HRA patients. Our algorithm considering blood Co and Cr levels predicts ALTR in ASR HRA patients with higher sensitivity than previously established guidelines.

Background: Despite the large number of studies assessing adverse local tissue reaction (ALTR) in metal-on-metal (MoM) hip implants, there is still a lack of knowledge about the natural progression of ALTR. The aims of this study were to describe the natural course of changes in ALTR at mid- to long-term follow-up for patients treated with metal-on-metal hip arthroplasty and to determine possible risk factors associated with change in ALTR. Methods: A total of 158 patients (158 hips), 109 MoM hip resurfacing arthroplasties (HRAs) and 49 MoM total hip arthroplasties (THAs), with 2 clinical follow-ups including MARS-MRIs were included. The mean time from index operation to the first visit was 7.6 years (range 3.4–11.4 years), and the mean time between the 2 visits was 1.0 year (range 0.7–1.6 years). Results: The proportion of patients with moderate or severe ALTR did not increase significantly between the first and second visit for the MoM HRA group (14.7–15.6%; p = 0.850) or the MoM THA group (32.7–36.7%; p = 0.671). 8 (7.3%) HRA patients and 9 (18.4%) THA patients progressed in ALTR grade. None of the collected clinical variables was sensitive or specific in identifying patients with ALTR progression. Conclusions: Although ALTR prevalence was high in our cohort, clinically significant ALTR progression was rare. We were unable to find any predictors associated with ALTR change. This indicates that MARS-MRI remains a valuable tool in the follow-up of patients treated with MoM hip devices in identifying patients who may need revision surgery.

Background The purpose of this study was to identify which patient and clinical factors are predictive of adverse local tissue reaction (ALTR) and to use these factors to create a highly sensitive algorithm for indicating metal artifact reduction sequence magnetic resonance imaging (MARS-MRI) in Articular Surface Replacement (ASR) XL total hip arthroplasty patients. Our secondary aim was to compare our algorithm to existing national guidelines on when to take MARS-MRI in metal-on-metal total hip arthroplasty patients. Methods The study consisted of 137 patients treated with unilateral ASR XL implants from a prospective, multicenter study. Patients underwent MARS-MRI regardless of clinical presentation at a mean of 6.2 (range, 3.3-10.4) years from surgery. Univariate and multivariate analyses were conducted to determine which variables were predictive of ALTR. Predictors were used to create an algorithm to indicate MARS-MRI. Finally, we compared our algorithm's ability to detect ALTR to existing guidelines. Results We found a visual analog scale pain score ≥2 (odds ratio [OR] = 2.53; P = .023), high blood cobalt (OR = 1.05; P = .023), and male gender (OR = 2.37; P = .034) to be significant predictors of ALTR presence in our cohort. The resultant algorithm achieved 86.4% sensitivity and 60.2% specificity in detecting ALTR within our cohort. Our algorithm had the highest area under the curve and was the only guideline that was significantly predictive of ALTR (P = .014). Conclusion Our algorithm including patient-reported pain and sex-specific cutoffs for blood cobalt levels could predict ALTR and indicate MARS-MRI in our cohort of ASR XL metal-on-metal patients with high sensitivity. Level of Evidence Level II, diagnostic study.

Recent registry studies show that aseptic loosening secondary to osteolysis is the second leading cause of hip implant failure in patients implanted with metal-on-metal (MoM) bearings. The primary aim of our study was to report on the progression of acetabular osteolysis during mid-term follow-up in patients treated with MoM hip resurfacing arthroplasty (HRA) and MoM total hip arthroplasty (THA). The secondary aim was to identify independent predictors of osteolytic lesion progression. A total of 805 patients (805 hips) were included in this study (541 MoM HRA, 264 MoM THA) from a prospective, international clinical registry of the Articular Surface Replacement Hip System. Patients were enrolled a median of 6.6 years from surgery. Osteolytic lesion progression was defined either as any lesion developing de novo, or as an existing lesion progressing from radiolucency to osteolysis during the study period (range 0.5–4.3 years). The number of cases with any osteolysis or radiolucency was 21 (3.9%) for ASR HRA and 29 (11.0%) for ASR XL THA at enrollment and increased to 69 (12.8%) for ASR HRA and 41 (15.5%) for ASR XL THA after follow-up. Osteolytic lesion progression was found in 66 (12.2%) ASR HRA patients and 31 (11.7%) ASR XL THA patients. Multivariate models determined that lower acetabular version angle (OR 0.963, p = 0.011) and elevated whole blood chromium (OR 1.110, p = 0.044) were independent predictors of osteolytic lesion progression in ASR HRA. We suggest that physicians of patients implanted with ASR HRA implants closely monitor patients with higher chromium levels and lower version angles, as they are at increased risk for osteolytic lesion progression, and we recommend annual radiographic follow-up on all patients with ASR implants.

A higher cobalt/chromium (Co/Cr) ratio is thought to be associated with corrosion of the trunnion and increased adverse local tissue reaction (ALTR) risk in patients treated with metal-on-metal (MoM) hip arthroplasty. The main aim of this study was to investigate the diagnostic value of Co/Cr ratio in identifying ALTR in patients treated with MoM hip resurfacing arthroplasty and total hip arthroplasty (THA).A total of 310 unilateral patients were included. All patients received a metal artifact reduction sequence magnetic resonance imaging to detect ALTR. Blood Co and Cr levels were measured.MoM THA patients had a higher Co/Cr ratio than MoM hip resurfacing arthroplasty patients (1.7, interquartile range 1.2-3.1 vs 0.9, interquartile range 0.7-1.3, P.001). The continuous Co/Cr ratio, continuous Co, and Co ≥ 7 ppb were predictive of ALTR when tested in receiver-operating characteristic analyses. The most sensitive and specific cutoffs were found to be 1.4 for Co/Cr ratio (sensitivity = 80.0%; specificity = 48.7%) and 2.4 ppb for Co (sensitivity = 77.8%; specificity = 46.2%). In multivariate analysis, continuous Co, Co ≥ 7 ppb, and the receiver-operating characteristic analysis-generated cutoffs were associated with ALTR prevalence.Blood metal ions are strong, but not perfect, predictors of ALTR in patients with MoM hip arthroplasty. Higher Co/Cr ratios are associated with increased risk for ALTR in MoM THA. However, blood Co levels alone are as good a predictor of ALTR as the Co/Cr ratio. The most ALTR-sensitive cutoffs are lower than previously reported in the literature.

Data on the association between stem type and metal-on-metal (MoM) total hip arthroplasty (THA) performance are limited. The aim of this study is to investigate the effect of stem type on the prevalence of osteolysis and radiolucency, blood metal ion levels, and functional outcomes in patients with Articular Surface Replacement THA (ASR XL), a type of MoM THA.We analyzed 539 unilateral MoM THAs coupled with Summit (48%), Corail (35%), or S-ROM (17%) hip stems at a mean follow-up of 6.4 years. Fifty-four percent of the patients were male, and the mean age was 60 years. We studied radiographs, patient-reported outcome measures, and ion levels.Patients with S-ROM hip stems were 3.8 times more likely to have osteolysis (P = .003) and 7.6 times more likely to have radiolucency (P.001) than those treated with Summit hip stems. In addition, patients treated with S-ROM hip stems scored worse than those with Summit hip stems in 4 of the 5 patient-reported outcome measures: Harris Hip Score, Visual Analog Scale pain, University of California at Los Angeles activity, and EQ-5D index. All these differences were statistically significant and ranged from 5% to 10%, which is clinically significant.Patients with S-ROM hip stems had inferior functional and radiographic results compared to patients with Summit hip stems. Retrieval studies on large diameter head MoM THA and close follow-up of these patients with hip stems are needed to understand the mechanism causing the differences in outcomes between these stem types.