Do psychiatric disorders affect patient reported outcomes and clinical outcomes post total hip and knee arthroplasty?

INTRODUCTION: The purpose of this study is to evaluate the role of major psychiatric illness on patient outcomes after total joint arthroplasty. METHODS: Patients with a diagnosis of a major psychiatric disorder undergoing total joint arthroplasty were retrospectively matched one-to-one with a cohort without such a diagnosis. Major psychiatric disorder in the registry was identified by diagnosis of anxiety, mood, or a psychotic disorder. Primary outcome of interest included perioperative Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Secondary outcomes included EuroQol-5D, adverse events, length of stay, 30-day readmission, and discharge destination. RESULTS: Total number of patients were 1828. The total hip arthroplasty (37.80 ± 17.91, p = 0.023) and the total knee arthroplasty psychiatric group (43.38 ± 18.41, p = 0.050) had significantly lower pre-operative WOMAC scores. At 3 months, the total hip arthroplasty (76.74 ± 16.94, p = 0.036) and total knee arthroplasty psychiatric group (71.09 ± 18.64, p < 0.01) again had significantly lower 3-month post-operative WOMAC score compared to the control groups. However, outcomes at 1 year were difficult to interpret, as patients with major psychiatric conditions had an extremely high loss to follow-up. Compared to the control groups, the total hip arthroplasty and total knee arthroplasty psychiatric group had an increased length of stay by 1.43 days (p < 0.01) and 0.77 days, respectively (p = 0.05). Similarly, the psychiatric groups were discharged directly home less often (total hip arthroplasty 86.9%, p = 0.024 and total knee arthroplasty 87.6%, p = 0.022) than the control groups. CONCLUSION: Patients with the diagnosis of a major psychiatric illness have an increased length of stay and are more likely to require a rehabilitation facility, compared to the control groups. Arguably, of utmost importance, there is a very high rate of loss to follow-up within the psychiatric groups. As such, we recommend these patients should be treated for their diagnosis prior to total joint arthroplasty. Furthermore, importance of clinical follow-up should be emphasized carefully.

Does Age Influence Patient-Reported Outcomes in Unilateral Primary Total Hip and Knee Arthroplasty?

BACKGROUND: Total hip arthroplasty (THA) and total knee arthroplasty (TKA) are used to treat patients with end-stage arthritis. Previous studies have not demonstrated a consistent relationship between age and patient-reported outcomes. The purpose of this study is to assess the impact of age on patient-reported outcomes after unilateral primary THA or TKA. METHODS: A retrospective review of available data in Alberta Bone and Joint Health Institute (ABJHI) Data Repository was performed. We identified 53,498 unilateral primary THA and TKA between April 2011 and 2017. Patients were divided by age into 3 categories: <55, 55-70, and >70. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and EuroQoL 5-dimension (EQ-5D) Canada scores were obtained at presurgery, 3 and 12 months postoperatively. RESULTS: For TKA, younger patients had larger improvements in WOMAC scores at 3 and 12 months (P = <.001-.033), and in EQ-5D scores at 3 months (P < .001). When adjusted, patients <55 had lower WOMAC and EQ-5D scores at 3 months postoperatively compared to those 55-70 or >70 (all P < .01). Outcomes at 12 months did not differ between age-groups. For THA, younger patients had larger improvements in WOMAC at 3 months (P = .03). When adjusted, patients <55 had higher WOMAC scores at 12 months postoperatively compared to those 55-70 or >70, and higher EQ-5D scores compared to those 55-70 (all P < .05). CONCLUSION: While a multitude of factors go in to quantifying successful THA or TKA, this study suggests that patient age should not be a deterrent when considering the impact of age on patient-reported outcomes.

Does body mass index affect the rate of adverse outcomes in total hip and knee arthroplasty? A retrospective review of a total joint replacement database

Background: Total hip arthroplasty (THA) and total knee arthroplasty (TKA) are reliable surgical options to treat pain and disability resulting from degenerative conditions around the hip and knee. Obesity is a modifiable risk factor that contributes to significant morbidity. The purpose of this study was to retrospectively compare outcomes in primary hip and knee arthroplasty for patients with increased body mass index (BMI) and those with normal BMI, using data from the registry of the Alberta Bone and Joint Health Institute (ABJHI). Methods: We retrospectively reviewed the data compiled in the ABJHI registry between March 2010 and July 2016. We reviewed outcomes with respect to length of stay, discharge destination, 30-day readmission, postoperative infection, postoperative transfusion requirements, postoperative adverse events and in-hospital postoperative mechanical complications. Results: A total of 10 902 patients (6076 women, 4826 men) who underwent THA and 16 485 patients (10 057 women, 6428 men) who underwent TKA were included in the study. For both THA and TKA, patients with increased BMI had an increased number of in-hospital medical events, had an increased rate of deep infection, were less likely to be discharged home (p < 0.001) and had decreased transfusion requirements (p < 0.001) than patients whose weight was in the normal range. Increased BMI increased the rate of 30-day readmission and length of stay in the THA cohort but not in the TKA cohort. Increased BMI had no effect on acute postoperative dislocation or periprosthetic fractures. Patients with a BMI of 30 kg/m2 or greater required a THA 1.7 years earlier than patients of normal weight, patients whose BMI was 35 kg/m2 or greater required a THA 3.4 years earlier, and patients whose BMI was 40 kg/m2 or greater required a THA 5.8 years earlier. In the TKA cohort, patients with a BMI of 30 kg/m2 or greater required a TKA 2.7 years earlier than patients whose weight was in the normal range, patients with a BMI of 35 kg/m2 or greater required a TKA 4.6 years earlier, and patients whose BMI was 40 kg/m2 or greater required a TKA 7.6 years earlier. Conclusion: Our study quantifies the effects of obesity in primary hip and knee arthroplasty. It provides a greater understanding of the risks in the obese population when contemplating joint arthroplasty.

Contexte: La prothèse totale de la hanche (PTH) et la prothèse totale du genou (PTG) sont des options chirurgicales fiables pour traiter la douleur et l'invalidité résultant de maladies dégénératives de la hanche et du genou. L'obésité est un facteur de risque modifiable qui contribue significativement à la morbidité. Le but de cette étude était de comparer de manière rétrospective le résultat des interventions primaires pour prothèses de la hanche et du genou selon que les patients avaient un indice de masse corporelle (IMC) normal ou élevé à partir des données du registre de l'Alberta Bone and Joint Health Institute (ABJHI). Méthodes: Nous avons analysé de manière rétrospective les données compilées par le registre de l'ABJHI entre mars 2010 et juillet 2016. Nous avons passé en revue les paramètres suivants : durée du séjour hospitalier, destination post-congé, réadmissions dans les 30 jours, infections postopératoires, besoins transfusionnels postopératoires, complications postopératoires et complications mécaniques postopératoires perhospitalières. Résultats: En tout, 10 902 patients (6076 femmes, 4826 hommes) ayant subi une PTH et 16 485 patients (10 057 femmes, 6428 hommes) ayant subi une PTG ont été inclus dans l'étude. Tant pour la PTH que pour la PTG, les patients ayant un IMC élevé ont présenté un plus grand nombre de complications médicales en cours d'hospitalisation; ils ont aussi présenté un nombre plus élevé d'infections profondes, étaient moins susceptibles de pouvoir retourner chez eux au moment de leur congé (p < 0,001) et ont eu moins besoin de transfusions (p < 0,001) comparativement aux patients dont le poids se situait dans l'éventail des valeurs normales. L'IMC élevé a été en corrélation avec une augmentation du taux de réadmission à 30 jours et de la durée du séjour dans la cohorte soumise à une PTH, mais non dans la cohorte soumise à une PTG. L'IMC élevé n'a exercé aucun effet sur la dislocation postopératoire aiguë ou les fractures périprothétiques. Les patients ayant un IMC de 30 kg/m2 ou plus ont eu besoin d'une PTH 1,7 an plus tôt que les patients de poids normal, les patients ayant un IMC de 35 kg/m2 ou plus ont eu besoin d'une PTH 3,4 ans plus tôt, et les patients ayant un IMC de 40 kg/m2 ou plus ont eu besoin d'une PTH 5,8 ans plus tôt. Dans la cohorte soumise à la PTG, les patients ayant un IMC de 30 kg/m2 ou plus ont eu besoin d'une PTG 2,7 ans plus tôt que les patients de poids normal, les patients ayant un IMC de 35 kg/m2 ou plus ont eu besoin d'une PTG 4,6 ans plus tôt, et les patients ayant un IMC de 40 kg/m2 ou plus ont eu besoin d'une PTG 7,6 ans plus tôt. Conclusion: Notre étude quantifie les effets de l'obésité sur le recours aux interventions primaires pour prothèse de la hanche et du genou. Elle permet de mieux comprendre les risques auxquels est exposée la population obèse lorsqu'une intervention pour prothèse articulaire est envisagée.

Adherence to human epidermal growth factor receptor-2 testing and adjuvant trastuzumab treatment guidelines in Ontario.

OBJECTIVES: We evaluated adherence of human epidermal growth factor receptor-2 testing using immunohistochemistry and fluorescence in situ hybridization, as well as adjuvant trastuzumab treatment according to Canadian guidelines, and predictors of trastuzumab use in early-stage breast cancer in Ontario. METHODS: Retrospective cohort of early-stage breast cancer patients identified in the Ontario Cancer Registry. Human epidermal growth factor receptor-2 test type, sequence, result(s), tumor grade, and hormone receptor status were abstracted from Ontario Cancer Registry pathology reports. Trastuzumab treatment was determined from provincial cancer agency records. Other variables were determined from administrative data sources. Logistic regression models were used to estimate adjusted odds ratios for factors associated with guideline adherence. RESULTS: The first human epidermal growth factor receptor-2 test result was the strongest predictor of confirmatory testing (p < 0.05). Human epidermal growth factor receptor-2 testing by immunohistochemistry accounted for the majority of documented first tests (94%; n = 8249). Overall, 27% (n = 2360) of tested patients received a second test by fluorescence in situ hybridization (46%) or immunohistochemistry (49%) assay. Most human epidermal growth factor receptor-2 equivocal patients (89%; n = 784) received a confirmatory test. Among human epidermal growth factor receptor-2-positive patients, only 57% (n = 385) received trastuzumab treatment within the study period. Human epidermal growth factor receptor-2 status was the strongest predictor of trastuzumab use. Younger patients (<70 years at diagnosis) and negative hormone receptor status had higher odds of trastuzumab treatment (p < 0.05) compared to older and positive hormone receptor status patients. CONCLUSIONS: Immunohistochemistry use as a first test was largely consistent with Canadian guidelines; however, immunohistochemistry was frequently used as a confirmatory test, which is not guideline-concordant. Monitoring these testing and treating patterns is necessary to optimize health outcomes associated with trastuzumab.

Impact of preoperative mental health status on functional outcome 1 year after total hip arthroplasty

Background: The aim of this prospective cohort study was to determine the effect of preoperative mental health status on functional outcome 1 year after total hip arthroplasty (THA). Methods: Data were collected for 677 patients from a randomized controlled trial in Alberta who received primary THA between April 2005 and June 2006 (sex, age, body mass index [BMI], comorbidities, back pain and need for another lower limb arthroplasty procedure within 1 yr after surgery). The Western Ontario and McMaster University Osteoarthritis Index (WOMAC) and 36-Item Short Form Health Survey (SF-36) mental health component were administered before surgery and 1 year after. We conducted multiple linear regression to determine the effect of mental health on the WOMAC score at 1 year. Results: The mean WOMAC and SF-36 mental health scores were significantly increased at 1 year (p < 0.001 and p = 0.01, respectively). There was a strong correlation between improvement in WOMAC score at 1 year and presurgery SF-36 mental health score (0.13, 95% confidence interval [CI] 0.06 to 0.2). Age (­0.34, 95% CI ­0.45 to ­0.24), obesity (­2.9, 95% CI ­5.32 to ­0.4), back pain (­5.75, 95% CI ­8.04 to ­3.46) and awaiting another joint arthroplasty operation (­6.18, 95% CI ­8.9 to ­3.47) had a negative impact on the WOMAC score. Conclusion: There was a strong correlation between presurgery mental health and the resolution of pain and improved functioning 1 year after THA. We recommend that patients receive appropriate counselling and, where appropriate, medical therapy before THA.

Contexte: Le but de cette étude de cohorte prospective était de déterminer l'effet de l'état de santé mentale préopératoire sur les résultats fonctionnels une année après une intervention pour prothèse totale de la hanche (PTH). Méthodes: Les données concernant 677 patients opérés pour PTH entre avril 2005 et juin 2006 ont été recueillies à partir d'un essai randomisé et contrôlé albertain (sexe, âge, indice de masse corporelle [IMC], comorbidités, dorsalgie et autre arthroplastie d'un membre inférieur requise dans l'année suivant l'intervention). L'indice WOMAC (Western Ontario and McMaster University Osteoarthritis Index) et le volet santé mentale du questionnaire SF-36 (36-Item Short Form Health Survey) ont été administrés avant la chirurgie, puis 1 an après. Nous avons réalisé une analyse de régression linéaire multiple pour déterminer l'effet de la santé mentale sur l'indice WOMAC après 1 an. Résultats: Les scores WOMAC et volet santé mentale du SF-36 étaient significativement plus élevé après 1 an (p < 0,001 et p = 0,01, respectivement). On a noté une forte corrélation entre l'amélioration du score WOMAC après 1 an et le score au volet santé mentale du SF-36 préopératoire (0,13, intervalle de confiance [IC] de 95 % 0,06 à 0,2). L'âge (­0,34, IC de 95 % ­0,45 à ­0,24), l'obésité (­2,9, IC de 95 % ­5,32 à ­0,4), la dorsalgie (­5,75, IC de 95 % ­8,04 à ­3.46) et l'attente d'une autre arthroplastie (­6,18, IC de 95 % ­8,9 à ­3,47) ont eu un impact négatif sur le score WOMAC. Conclusion: On a observé une forte corrélation entre l'état de santé mentale préopératoire et la résolution de la douleur/amélioration du fonctionnement un an après la PTH. Nous recommandons un counselling approprié et selon le cas un traitement médical avant la PTH.

Association between Allogeneic Blood Transfusion and Wound Infection after Total Hip or Knee Arthroplasty: A Retrospective Case-Control Study.

Background: To assess using a retrospective case control study, whether patients undergoing primary, elective total hip or knee arthroplasty who receive blood transfusion have a higher rate of post-operative infection compared to those who do not. Materials and Methods: Data on elective primary total hip or knee arthroplasty patients, including patient characteristics, co-morbidities, type and duration of surgery, blood transfusion, deep and superficial infection was extracted from the Alberta Bone and Joint Health Institute (ABJHI). Logistic regression analysis was used to compare deep infection and superficial infection in blood-transfused and non-transfused cohorts. Results: Of the 27892 patients identified, 3098 (11.1%) received blood transfusion (TKA 9.7%; THA 13.1%). Overall, the rate of superficial infection (SI) was 0.5% and deep infection (DI) was 1.1%. The infection rates in the transfused cohort were SI 1.0% and DI 1.6%, and in the non-transfused cohort were SI 0.5% and DI 1.0%. The transfused cohort had an increased risk of superficial infection (adjusted odds ratio (OR) 1.9 [95% CI 1.2-2.9, p-value 0.005]) as well as deep infection (adjusted OR 1.6 [95% CI 1.1-2.2, p-value 0.008]). Conclusion: The odds of superficial and deep wound infection are significantly increased in primary, elective total hip and knee arthroplasty patients who receive blood transfusion compared to those who did not. This study can potentially help in reducing periprosthetic hip or knee infections.

Cost-utility of metal-on-metal hip resurfacing compared to conventional total hip replacement in young active patients with osteoarthritis.

BACKGROUND: Metal-on-metal hip resurfacing arthroplasty (MoM HRA) has emerged as an alternative to total hip arthroplasty (THA) for younger active patients with osteoarthritis (OA). Birmingham hip resurfacing is the most common MoM HRA in Alberta, and is therefore compared with conventional THA. OBJECTIVE: The objective of this study was to estimate the expected cost-utility of MoM HRA versus THA, in younger patients with OA, using a decision analytic model with a 15-year time horizon. METHODS: A probabilistic Markov decision analytic model was constructed to estimate the expected cost per quality-adjusted life-year (QALY) of MoM HRA versus THA from a health care payer perspective. The base case considered patients with OA aged 50 years; men comprised 65.9% of the cohort. Sensitivity analyses evaluated cohort age, utility values, failure probabilities, and treatment costs. Data were derived from the Hip Improvement Project and the Hip and Knee Replacement Pilot databases in Alberta, the 2010 National Joint Replacement Registry of the Australian Orthopaedic Association, and the literature. RESULTS: In the base case, THA was dominated by MoM HRA (incremental mean costs of -$583 and incremental mean QALYs of 0.079). In subgroup analyses, THA remained dominated when cohort age was 40 years instead of 50 years or when only men were assessed. THA dominated when the cohort age was 60 years or when only women were assessed. Results were sensitive to utilities, surgery costs, and MoM HRA revision and conversion probabilities. At a willingness-to-pay of Can $50,000/QALY, there was a 58% probability that MoM HRA is cost-effective. CONCLUSIONS: The results show that, on average, MoM HRA was preferred to THA for younger and male patients, but THA is still a reasonable option if the patient or clinician prefers given the small absolute differences between the options and the confidence ellipses around the cost-effectiveness estimates.

Closing the personalized medicine information gap: HER2 test documentation practice.

BACKGROUND: Uncertainty about human epidermal growth factor receptor-2 (HER2) testing practice in Canada continues to hinder efforts to improve personalized medicine. Pathologists routinely perform HER2 assessment for all tumors > 1 cm, and pathology is reported centrally to the provincial cancer registry. OBJECTIVES: To understand patterns of HER2 test documentation for early-stage breast cancer (BC) patients in Ontario's centralized pathology reporting system. STUDY DESIGN: Retrospective cohort study of central HER2 test documentation in early-stage BC patients diagnosed in 2006-2007. METHODS: Cohort and staging information was derived from cancer registry and admissions data. Linkage across administrative databases provided data on surgical and radiologic treatment, sociodemographic factors, diagnosis setting, and comorbidities. Pathology reports from the provincial cancer registry were reviewed for HER2 testing, hormone receptor, and grade. Unadjusted and adjusted odds ratios were calculated to determine factors related to HER2 documentation. RESULTS: A HER2 test was documented for 66% of 13,396 patients. HER2 documentation was associated with stage, hormone receptor, and tumor grade documentation. Higher stage and grade at diagnosis were also associated with HER2 documentation. All models suggested variable regional documentation patterns. Documentation did not differ by sociodemographic factors, presence of comorbidities, or surgical procedure. CONCLUSIONS: Despite a universal testing policy, the rate of centralized HER2 test documentation was lower than expected and related to disease severity. Differences in regional reporting likely reflect ascertainment bias inherent to centralized pathology reporting rather than testing access. Improved HER2 reporting is encouraged for cancer registration, quality-of-care measurement, and program evaluation.

Functional outcomes for 2 years comparing hip resurfacing and total hip arthroplasty.

This prospective observational study of 499 patients with hip resurfacing and 255 patients with total hip arthroplasty compared outcomes for 2 years. We used propensity scores to identify matched cohorts of 118 patients with hip resurfacing and 118 patients with total hip arthroplasty. We used these cohorts to compare improvements in the Western Ontario and McMaster University (WOMAC) osteoarthritis index and Medical Outcomes Short-Form 36 physical function component (SF-36 PF) scores at 3 months and at 1 and 2 years postsurgery. Both groups demonstrated significant improvements from baseline in WOMAC and SF-36 PF. Improvements in SF-36 PF were greater for patients with hip resurfacing than for patients with total hip arthroplasty 1 and 2 years postsurgery; improvements in WOMAC were similar for both groups. The clinical significance of this observation needs further investigation.

Measuring the value of total hip and knee arthroplasty: considering costs over the continuum of care.

BACKGROUND: Controlling escalating costs of hip (THA) and knee arthroplasty (TKA) without compromising quality of care has created the need for innovative system reorganization to inform sustainable solutions. QUESTIONS/PURPOSES: The purpose of this study was to inform estimates of the value of THA and TKA by determining: (1) the data sources data required to obtain costs across the care continuum; (2) the data required for different analytical perspectives; and (3) the relative costs across the continuum of care. METHODS: Within the context of a pragmatic randomized controlled trial comparing alternative care pathways, we captured healthcare resource use: (1) 12 months before surgery; (2) inpatient; (3) acute recovery; and (4) long-term recovery 3 and 12 months postsurgery. We established a standardized costing model to reflect both the healthcare payer and patient perspectives. RESULTS: Multiple data sources from regional health authorities, administrative databases, and patient questionnaire were required to estimate costs across the care continuum. Inpatient and acute care costs were approximately 60% of the total with the remaining 40% incurred 12 months presurgery and 12 months postsurgery. Regional health authorities bear close to 60%, and patient costs are approximately 30% of the mean total costs, most of which were incurred after the acute inpatient stay. CONCLUSIONS: To fully understand the value of an orthopaedic intervention such as THA and TKA, a broader perspective than one limited to the payer should be considered using a standardized measurement framework over a relevant time horizon and from multiple viewpoints to reflect the substantial patient burden and support sustainable improvement over the care continuum. LEVEL OF EVIDENCE: Level III, economic and decision analyses study. See Guidelines for Authors for a complete description of levels of evidence.

Comparison of risk factors between preterm and term infants hospitalized for severe respiratory syncytial virus in the Russian Federation.

BACKGROUND: Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infection in infants. Preterm birth, in addition to several demographic and environmental factors, increases the risk for development of severe RSV infection. The purpose of this study was to describe differences in risk factors and protective factors between preterm birth (up to 35 weeks' gestational age) and term infants hospitalized for RSV lower respiratory tract infection in the Russian Federation during the 2008-2009 RSV season. METHODS: Infants up to two years of age hospitalized for a lower respiratory tract infection in Moscow, St Petersburg, and Tomsk were tested for RSV. Patient data, including risk factors and protective factors for RSV, were captured at admission. Differences in these factors were compared between preterm and term patients. RESULTS: A total of 519 infants hospitalized for lower respiratory tract infection were included in the study. Of these, 197 infants (182 term and 15 preterm) tested positive for RSV. Of all hospitalizations, 51.7% (15/29) of preterm infants versus 37.1% (182/490) of term infants had confirmed RSV (P = 0.118). Among the RSV-positive patients, preterm infants were more likely to have a lower weight at admission (P = 0.050), be of multiple gestation (P < 0.001), have more siblings (P = 0.013), and have more siblings under the age of eight years (P < 0.007) compared with term patients. The preterm infants were less likely to be breastfed (P < 0.001) and more likely to have older mothers (P = 0.050). CONCLUSION: Compared with term infants, RSV was a more prevalent cause of hospitalization for lower respiratory tract infection in preterm infants. Of infants hospitalized for RSV, preterm infants were more likely to have additional risk factors for severe RSV. These findings suggest that preterm infants may be exposed to a combination of more strongly interrelated risk factors for severe RSV than term infants.

The Alberta Hip and Knee Replacement Project: a model for health technology assessment based on comparative effectiveness of clinical pathways.

BACKGROUND: The Alberta Hip and Knee Replacement Project developed a new evidence-based clinical pathway (NCP) for total hip (THR) and knee (TKR) replacement. The aim was to facilitate the delivery of services in a timely and cost-effective manner while achieving the highest quality of care for the patient across the full continuum of care from patient referral to an orthopedic surgeon through surgery, recovery, and rehabilitation. The purpose of this article is to provide an overview of the study design, rationale, and execution of this project as a model for health technology assessment based on comparative effectiveness of alternative clinical pathways. METHODS: A pragmatic randomized controlled trial study design was used to evaluate the NCP compared with the standard of care (SOC) for these procedures. The pragmatic study design was selected as a rigorous approach to produce high quality evidence suitable for informing decisions between relevant interventions in real clinical practice. The NCP was evaluated in three of the nine regional health authorities (RHAs) in Alberta with dedicated central intake clinics offering multidisciplinary care teams, constituting 80 percent of THR and TKR surgeries performed annually in Alberta. Patients were identified in the offices of twenty orthopedic surgeons who routinely performed THR or TKR surgeries. Evaluation outcome measures were based on the six dimensions of the Alberta Quality Matrix for Health (AQMH): acceptability, accessibility, appropriateness, effectiveness, efficiency and safety. Data were collected prospectively through patient self-completed questionnaires at baseline and 3 and 12 months after surgery, ambulatory and inpatient chart reviews, and electronic administrative data. RESULTS: The trial design was successful in establishing similar groups for rigorous evaluation. Of the 4,985 patients invited to participate, 69 percent of patients consented. A total of 3,434 patients were randomized: 1,712 to SOC and 1,722 to the NCP. The baseline characteristics of patients in the two study arms, including demographics, comorbidity as measured by CDS and exposure to pain medications, and health-related quality of life, as measured by Western Ontario and McMaster Universities Osteoarthritis Index and Short Form-36, were similar. CONCLUSIONS: The Alberta Hip and Knee Replacement Project demonstrates the feasibility and advantages of applying a pragmatic randomized controlled trial to ascertain comparative effectiveness. This is a model for health technology assessment that incorporates how clinical pathways can be effectively evaluated.