Tibial Slope Is Not Associated With Implant Migration Following Cemented Total Knee Arthroplasty With a Single Implant Design.

BACKGROUND: The influence of tibial slope on tibial component migration following total knee arthroplasty has not been widely studied, although excessive posterior slope has been implicated in some failures. As implant micromotion measured with radiostereometric analysis can indicate successful fixation, the purpose of this study was to determine the associations between tibial slope, tibial component migration, and inducible displacement. METHODS: Radiostereometric analyses at 6 visits over 2 years quantified implant migration for 200 cemented total knee arthroplasties. Longitudinal data analysis examined the influence of postoperative tibial slope on implant migration (overall maximum total point motion (MTPM) migration and anterior-posterior tilt migration), accounting for age, sex, and body mass index. The correlations of tibial slope with 1-year migration, continuous migration, and inducible displacements were also examined. Additionally, the amount of change in slope was compared to migration. RESULTS: The mean posterior tibial slope was 8.0° (standard deviation [SD] 3.8°) preoperatively and 3.8° (SD 3.1°) postoperatively, with a mean reduction in slope of 4.2° (SD 4.7°). Postoperative tibial slope (range 14.0° posterior slope to 3.4° anterior slope) was not associated with longitudinal overall migration (P = .671) or anterior-posterior tilt migration (P = .704). There was no association between postoperative tibial slope and migration at 1 year postoperatively (P = .441 for MTPM migration, P = .570 for tilt migration), change in migration from 1 to 2 years (P = .951), or inducible displacement (P = .970 MTPM, P = .730 tilt). The amount of change in tibial slope was also not associated with migration or inducible displacement. CONCLUSIONS: Residual and change in postoperative tibial slope were not associated with implant migration into tilt or overall migration, or inducible displacement for a single implant design. These findings support positioning tibial implants in a range of slopes, which may support patient-specific approaches to implant alignment.

Video-based assessment (VBA) of an open, simulated orthopedic surgical procedure: a pilot study using a single-angle camera to assess surgical skill and decision making.

BACKGROUND: Videos have been used in many settings including medical simulation. Limited information currently exists on video-based assessment in surgical training. Effective assessment tools have substantial impact on the future of training. The objectives of this study were as follows: to evaluate the inter-rater reliability of video-based assessment of orthopedic surgery residents performing open cadaveric simulation procedures and to explore the benefits and limitations of video-based assessment. METHODS: A multi-method technique was used. In the quantitative portion, four residents participated in a Surgical Objective Structured Clinical Examination in 2017 at a quaternary care training center. A single camera bird's-eye view was used to videotape the procedures. Five orthopedic surgeons evaluated the surgical videos using the Ottawa Surgical Competency Operating Room Evaluation. Interclass correlation coefficient was used to calculate inter-rater reliability. In the qualitative section, semi-structured interviews were used to explore the perceived strengths and limitations of video-based assessment. RESULTS AND DISCUSSION: The scores using video-based assessment demonstrated good inter-rater reliability (ICC = 0.832, p = 0.014) in assessing open orthopedic procedures on cadavers. Qualitatively, the strengths of video-based assessment in this study are its ability to assess global performance and/or specific skills, ability to reassess missed points during live assessment, and potential use for less common procedures. It also allows for detailed constructive feedback, flexible assessment time, anonymous assessment, multiple assessors and serves as a good coaching tool. The main limitations of video-based assessment are poor audio-video quality, and questionable feasibility for assessing readiness for practice. CONCLUSION: Video-based assessment is a potential adjunct to live assessment in orthopedic open procedures with good inter-rater reliability. Improving audio-video quality will enhance the quality of the assessment and improve the effectiveness of using this tool in surgical training.

Cost comparison between spinal versus general anesthesia for hip and knee arthroplasty: an incremental cost study.

PURPOSE: Wait list times for total joint arthroplasties have been growing, particularly in the aftermath of the COVID-19 pandemic. Increasing operating room (OR) efficiency by reducing OR time and associated costs while maintaining quality allows the greatest number of patients to receive care. METHODS: We used propensity score matching to compare parallel processing with spinal anesthesia in a block room vs general anesthesia in a retrospective cohort of adult patients undergoing primary total hip arthroplasty (THA) and total knee arthroplasty (TKA). We compared perioperative costs, hospital costs, OR time intervals, and complications between the groups with nonparametric tests using an intention-to-treat approach. RESULTS: After matching, we included 636 patients (315 TKA; 321 THA). Median [interquartile range (IQR)] perioperative costs were CAD 7,417 [6,521-8,109], and hospital costs were CAD 10,293 [9,344-11,304]. Perioperative costs were not significantly different between groups (pseudo-median difference [MD], CAD -47 (95% confidence interval [CI], -214 to -130; P = 0.60); nor were total hospital costs (MD, CAD -78; 95% CI, -340 to 178; P = 0.57). Anesthesia-controlled time and total intraoperative time were significantly shorter for spinal anesthesia (MD, 14.6 min; 95% CI, 13.4 to 15.9; P < 0.001; MD, 15.9; 95% CI, 11.0 to 20.9; P < 0.001, respectively). There were no significant differences in complications. CONCLUSION: Spinal anesthesia in the context of a dedicated block room reduced both anesthesia-controlled time and total OR time. This did not translate into a reduction in incremental cost in the spinal anesthesia group.

RéSUMé: OBJECTIF: Les temps d'attente pour les arthroplasties articulaires totales ont augmenté, en particulier à la suite de la pandémie de COVID-19. Une augmentation de l'efficacité de la salle d'opération (SOP) fondée sur une réduction du temps en salle d'opération et des coûts associés, tout en maintenant la qualité, permettrait à un plus grand nombre de patients de recevoir des soins. MéTHODE: Nous avons utilisé l'appariement par score de propension pour comparer en parallèle des traitements par rachianesthésie dans une salle de bloc vs par anesthésie générale dans une cohorte rétrospective de patients adultes bénéficiant d'une arthroplastie totale de la hanche (ATH) et d'une arthroplastie totale du genou (ATG) primaires. Nous avons comparé les coûts périopératoires, les coûts hospitaliers, les intervalles de temps en SOP et les complications entre les groupes avec des tests non paramétriques en utilisant une approche d'intention de traiter. RéSULTATS: Après appariement, nous avons inclus 636 patients (315 ATG; 321 ATH). Les coûts périopératoires médians [écart interquartile (ÉIQ)] étaient de 7417 $ CA [6521 ­ 8109] et les coûts hospitaliers de 10 293 $ CA [9344 ­ 11 304]. Les coûts périopératoires n'étaient pas significativement différents entre les groupes (différence pseudomédiane [DM], −47 $ CA (intervalle de confiance à 95 % [IC], −214 à −130; P = 0,60), pas plus que les coûts hospitaliers totaux (DM, −78 $ CA; IC 95 %, −340 à 178; P = 0,57). Le temps sous anesthésie et le temps peropératoire total étaient significativement plus courts pour la rachianesthésie (DM, 14,6 min; IC 95 %, 13,4 à 15,9; P < 0,001; DM, 15,9; IC 95 %, 11,0 à 20,9; P < 0,001, respectivement). Aucune différence significative n'a été observée dans les complications. CONCLUSION: La rachianesthésie dans un contexte de salle de bloc dédiée a réduit à la fois le temps sous anesthésie et le temps total de SOP. Cela ne s'est pas traduit par une réduction du coût différentiel dans le groupe recevant une rachianesthésie.

Morbid Obesity and Severe Knee Osteoarthritis: Which Should Be Treated First?

BACKGROUND: There are limited prospective data, and conflicting retrospective data, providing guidance on how to optimally manage patients with morbid obesity and severe knee osteoarthritis. This study sought to review the effect of bariatric surgery on knee pain and knee surgery 30-day outcomes, as well as assess whether the sequence of bariatric and knee surgery has any effect on 30-day complications. METHODS: A retrospective chart review of all patients undergoing laparoscopic sleeve gastrectomy (LSG) from July 2006 to July 2016 at a university hospital was performed. Patients with knee pain or knee surgery (pre- or post-LSG) were identified using bariatric and orthopedic clinic notes. Those who had improvement in knee pain following LSG resulting in removal from orthopedic surgery waitlist were identified. We also assessed surgical outcomes in patients undergoing knee arthroscopy or total knee arthroplasty (TKA) followed by LSG compared to patients undergoing LSG followed by knee arthroscopy or TKA. RESULTS: During our study timeframe, 355 patients underwent LSG. Knee pain was documented in 150 (42.2%) patients, and orthopedic surgery consultation was completed for 57 (38.0%) patients with knee pain. Orthopedic intervention was performed prior to LSG for 24 patients and after LSG for 27 patients. Procedures were a combination of arthroscopy (18) and TKA (33). Six patients were removed from the waitlist for TKA following LSG due to resolution of symptoms. Order of interventions did not affect 30-day complications for patients undergoing LSG and arthroscopy (16% arthroscopy first, 0% LSG first, p = 0.43). A higher rate of LSG complications was noted in patients who underwent TKA prior to LSG (25% vs 0%, p = 0.04). There were no differences in TKA complications (8.3% TKA first, 4.8% LSG first, p = 1.00). CONCLUSION: In a small number of patients with morbid obesity and severe knee osteoarthritis, orthopedic intervention can be delayed and potentially avoided by undergoing LSG. In our study, 6/57 (10.5%) of patients with orthopedic consultation prior to LSG saw resolution of symptoms of knee pain. Referral to bariatric surgery should be considered for patients with morbid obesity and severe knee osteoarthritis.

Variable effects of obesity on access to total hip and knee arthroplasty.

Background: Obesity is an important comorbidity affecting outcomes after total joint arthroplasty. Consequently, surgeons may delay care of obese patients to first address obesity through different care pathways. The effect of obesity on patient wait times for total joint arthroplasty has not been explored. The purpose of this study was to evaluate the effect of obesity on access to total hip (THA) and knee (TKA) arthroplasty. Methods: The study data set was constructed from the Nova Scotia Health Authority's Horizon Patient Folder system and the Patient Access Registry Nova Scotia. Wait time was measured as days between the decision to treat and date of surgery. Body mass index (BMI) was calculated from a preoperative assessment, and patients were grouped into BMI categories. Multivariate log-linear regression was used to test for statistical differences, controlling for confounding factors. Results: We observed longer wait times for TKA with increasing BMI weight class. Patients with BMIs greater than 50 had 34% longer waits than reference weight patients. However, THA recipients showed no statistical difference in wait times across weight categories. Furthermore, there was variability among surgeons in the wait times experienced by patients. Conclusion: The finding of longer wait times for TKAs, but not THAs, among patients who were obese was unexpected. This shows the variable wait times for THA and TKA that patients who are obese can experience with different surgeons. It is important to understand the variability in wait times so that efforts to standardize the patient experience can be accomplished.

Contexte: L'obésité est une comorbidité importante qui a des répercussions sur les résultats d'une arthroplastie totale. Ainsi, les chirurgiens pourraient reporter les soins aux patients obèses afin de d'abord traiter l'obésité par différents parcours de soins. Les effets de l'obésité sur le temps d'attente pour une arthroplastie totale n'ont pas été étudiés. La présente étude visait donc à évaluer les effets de l'obésité sur l'accès à une arthroplastie totale de la hanche (ATH) ou du genou (ATG). Méthodes: L'ensemble de données à l'étude provient du système Horizon Patient Folder de la Régie de la santé de la Nouvelle-Écosse et du registre d'accès des patients de la Nouvelle-Écosse. Le temps d'attente a été défini comme étant le nombre de jours séparant la décision de traitement et la date de l'intervention. L'indice de masse corporelle (IMC) a été calculé selon les données recueillies lors d'une évaluation préopératoire, et les patients ont été classés par catégorie d'IMC. Une régression loglinéaire multiple a été utilisée pour mesurer les différences statistiques et tenir compte des facteurs de confusion. Résultats: Nous avons constaté que le temps d'attente pour une ATG augmente avec la catégorie d'IMC. En effet, les patients ayant un IMC de plus de 50 ont attendu 34 % plus longtemps que les patients du groupe de référence. Pourtant, il n'y avait aucune différence statistiquement significative entre les catégories d'IMC pour ce qui est du temps d'attente avant une ATH. De plus, le temps d'attente variait d'un chirurgien à l'autre. Conclusion: La conclusion selon laquelle les patients obèses attendent plus longtemps pour une ATG, mais pas pour une ATH, était inattendue. Cela met en évidence le temps d'attente variable que peuvent connaître les patients obèses selon les différents chirurgiens. Il est important de comprendre la variabilité du temps d'attente afin de normaliser l'expérience patient.

Quantifying Achievable Levels of Improvement in Knee Joint Biomechanics During Gait After Total Knee Arthroplasty Relative to Osteoarthritis Severity.

Total knee arthroplasty (TKA) surgery improves knee joint kinematics and kinetics during gait for most patients, but a lack of evidence exists for the level and incidence of improvement that is achieved. The objective of this study was to quantify patient-specific improvements in knee biomechanics relative to osteoarthritis (OA) severity levels. Seventy-two patients underwent 3-dimensional (3D) gait analysis before and 1 year after TKA surgery, as well as 72 asymptomatic adults and 72 with moderate knee OA. A combination of principal component analysis and discriminant analyses were used to categorize knee joint biomechanics for patients before and after surgery relative to asymptomatic, moderate, and severe OA. Post-TKA, 63% were categorized with knee biomechanics consistent with moderate OA, 29% with severe OA, and 8% asymptomatic. The magnitude and pattern of the knee adduction moment and angle (frontal plane features) were the most significant contributors in discriminating between pre-TKA and post-TKA knee biomechanics. Standard of care TKA improves knee biomechanics during gait to levels most consistent with moderate knee OA and predominately targets frontal plane features. These results provide evidence for the level of improvement in knee biomechanics that can be expected following surgery and highlight the biomechanics most targeted by surgery.

Graphical-based multivariate analysis for knee joint clinical and kinematic data correlation assessment.

A large amount of data including joint kinematics, joint kinetics, clinical and functional measurements constitutes the clinical gait analysis basis which is a process whereby quantitative gait information are collected to aid in clinical decision-making. Therefore, better understanding the relationship between the biomechanical and clinical data for the knee osteoarthritis (OA) patient is for a relevant importance. It's the purpose of this paper, which aims to analyze and visualize the correlation structure between biomechanical characteristics and clinical symptoms, and thus to provide an additional knowledge from the coupling of these parameters that will be useful for the pathology assessment of knee-joint disease in the end-staged knee OA patients. We perform two multivariate statistical approaches, first, a Canonical Correlation Analysis (CCA) to assess the multivariate association and, second, a graphical- based representation of the multivariate correlation to better understand the association between these multivariate data. Results show the usefulness of using such multivariate approaches to highlight association and specific correlation structure between the features and to extract meaningful information.

Higher periprosthetic fracture rate associated with use of modern uncemented stems compared to cemented stems in femoral neck fractures.

INTRODUCTION:: Hemiarthroplasty is the preferred treatment for displaced femoral neck fractures in elderly patients. Recently, short tapered-wedge cementless stems have increasingly been used in this population. However, historic data has consistently shown higher rates of periprosthetic fracture with uncemented stems in hip fracture patients. This study aims to evaluate the rate of periprosthetic fracture requiring re-operation and all-cause mortality between cemented and uncemented femoral stem designs including more recent short tapered-wedge cementless stems in hip fracture patients. METHODS:: A retrospective chart and radiographic review of patients received bipolar hemiarthroplasty for femoral neck fractures from 2010-2016. Patients biologically (age ≥ 65 years) or physiologically (American Society of Anesthesiologists (ASA) class ≥ 3) elderly were eligible. The uncemented group was subdivided into tapered-wedge stems (a broach only system) and reamed uncemented stems. The primary outcome was periprosthetic fracture requiring re-operation. RESULTS:: We included 657 patients in total, with 296 and 361 patients in the uncemented and cemented stem groups respectively. In the uncemented group there were 197 tapered-wedge and 99 reamed uncemented stems. There was a significantly higher rate of periprosthetic fracture requiring re-operation in the uncemented group (3.0% vs. 0.6%) ( p ≤ 0.05). There were no significant differences in rates of all-cause mortality, infection or all-cause re-operation. CONCLUSIONS:: Compared to modern uncemented femoral stem designs, cemented stems yield lower rates of periprosthetic fracture requiring re-operation, without increasing risk of all-cause mortality. Tapered-wedge stems had similar rates of re-operation due to periprosthetic fracture as reamed uncemented stems.

Knee motion and muscle activation patterns are altered in hip osteoarthritis: The effect of severity on walking mechanics.

BACKGROUND: Knee function is impaired in individuals with moderate hip osteoarthritis. How this extends to those undergoing total hip arthroplasty is unknown despite the common requirement for knee arthroplasty in this population. The study purpose was to determine whether sagittal plane knee joint movements and quadriceps and hamstring activation patterns differ between individuals with either moderate or severe unilateral hip osteoarthritis, and between ipsilateral and contralateral knees. METHODS: 20 individuals with moderate osteoarthritis and 20 with severe osteoarthritis were recruited. Sagittal knee motion and surface electromyograms from the hamstrings and quadriceps were collected during treadmill walking at a self-selected speed. Principal component analysis captured amplitude and temporal sagittal plane motion and EMG waveform features. Student's t-tests and Analysis of Variance determined between group differences and within/between group leg differences. FINDINGS: The severe groups' contralateral knee was in greater flexion at initial contact and demonstrated a movement profile of a longer stance phase (p < 0.001). The severe group had reduced sagittal plane knee motion (p < 0.0001); more so in the ipsilateral knee (p < 0.0001). The severe group had greater hamstring (p = 0.009) and quadriceps activation (p < 0.001) overall, specifically mid-stance quadriceps bilaterally (p = 0.002). Ipsilateral sagittal plane knee motion was reduced in both groups. Compared with those with moderate osteoarthritis, individuals with severe osteoarthritis walk with reduced sagittal plane knee motion bilaterally, suggesting prolonged contralateral stance, and elevated mid-stance hamstring and quadriceps activation. INTERPRETATION: Altered kinematics and muscle activity could contribute to a greater mechanical demand on the contralateral knee in those with more severe hip osteoarthritis.

The prognostic value of pain catastrophizing in health-related quality of life judgments after Total knee arthroplasty.

BACKGROUND: Total knee arthroplasty (TKA) is a highly effective procedure that yields reductions in pain and disability associated with end stage osteoarthritis (OA) of the knee. Quality of life instruments are frequently used to gauge the outcomes of total knee arthroplasty (TKA). However, research suggests that post-TKA reductions in symptom severity may not be the sole predictors of quality of life post-TKA. The primary objective of the present study was to examine the prognostic value of catastrophic thinking in health-related quality of life (HRQoL) judgments in patients with severe OA after TKA. METHODS: In this study we used a prospective cohort design to examine the value of pain catastrophizing in predicting HRQoL 1 year after TKA. Participants with advanced OA of the knee who were scheduled for TKA were recruited at one of three hospitals in Canada. The study sample consisted of 116 individuals (71 women, 45 men) who completed study questionnaires at their pre-surgical evaluation and 1 year after surgery. Hierarchical regression analysis was used to assess the unique contribution of pre-surgical pain catastrophizing to the prediction of post-surgical HRQoL judgments. RESULTS: The results of the hierarchical regression equation revealed that the overall model was significant, F (9,106) = 8.3, p < 001, and accounted for 36.4% of the variance in the prediction of post-surgical physical component score of HRQoL. Pain catastrophizing was entered in the last step of the equation and contributed significant unique variance (ß = -.35, p < .001) to the prediction of post-surgical physical component score of HRQoL above and beyond the variance accounted for by demographic variables, co-morbid health conditions, baseline HRQoL, and post-surgical reductions in pain, joint stiffness and physical disability. CONCLUSIONS: The current findings highlight the importance of pre-surgical catastrophic cognitions in influencing HRQoL judgments after TKA. The findings suggest that psychosocial interventions designed to reduce pain catastrophizing before TKA might contribute to better quality of life outcomes following surgery.

Risk factors for infection, revision, death, blood transfusion and longer hospital stay 3 months and 1 year after primary total hip or knee arthroplasty.

BACKGROUND: Total joint replacement (TJR) is increasingly performed in older patients with more comorbidities, who are considered at higher risk for postoperative complications. We aimed to identify and calculate the odds ratio of the risk factors for infection, revision and death 3 months and 1 year after TJR as well as for postoperative blood transfusion and longer hospital stay. METHODS: We analyzed all primary total hip arthroplasty (THA) and total knee arthroplasty (TKA) cases in Nova Scotia between Apr. 1, 2000, and Mar. 31, 2014, as identified from the Discharge Abstract Database. We used the Charlson Comorbidity Index as a surrogate measure of comorbidities. We used hospital and physician billings data and Nova Scotia Vital Statistics data to identify the postoperative events in this cohort. RESULTS: A total of 10 123 primary THA and 17 243 primary TKA procedures were performed during the study period. The mean patient age was 66.1 (standard deviation 11.7) years and 67.1 (standard deviation 9.3) years, respectively. With THA, the risk of infection was higher in patients with heart failure and those with diabetes. For TKA, liver disease and blood transfusion were associated with a higher risk of infection. Revision rates were higher among patients with hypertension and those with paraparesis/hemiparesis for THA, and among patients with metastatic disease for TKA. Significant risk factors for death included metastatic disease, older age, heart failure, myocardial infarction, dementia, rheumatologic disease, renal disease, blood transfusion and cancer. Multiple medical comorbidities and older age were associated with higher rates of blood transfusion and longer hospital stay. CONCLUSION: We have identified the risk factors associated with higher rates of postoperative complications and longer hospital stay after TJR. The results enable individualized risk stratification during the preoperative consultation.

CONTEXTE: Les arthroplasties totales (AT) sont de plus en plus pratiquées chez les patients âgés présentant de plus nombreuses comorbidités et considérés de ce fait exposés à un risque accru de complications postopératoires. Nous avons voulu déterminer et calculer le rapport des cotes pour les facteurs de risque d'infection, de révision chirurgicale et de décès 3 mois et 1 an après l'AT, de même que de transfusions sanguines postopératoires et de prolongation du séjour hospitalier. MÉTHODES: Nous avons analysé toutes les interventions primaires pour prothèse totale de la hanche (PTH) et prothèse totale du genou (PTG) en Nouvelle-Écosse entre le 1er avril 2000 et le 31 mars 2014, répertoriées dans la base de données sur les congés des patients. Nous avons utilisé le score de comorbidité de Charlson comme marqueur de substitution des comorbidités. Nous avons utilisé les données de facturation des hôpitaux et des médecins et les données de l'état civil de la Nouvelle-Écosse pour recenser les événements postopératoires dans cette cohorte. RÉSULTATS: En tout, 10 123 PTH primaires et 17 243 PTG primaires ont été effectuées pendant la période de l'étude. L'âge moyen des patients était de 66,1 ans (écart-type 11,7) et de 67,1 ans (écart-type 9,3), respectivement. Avec la PTH, le risque d'infection a été plus élevé chez les patients atteints d'insuffisances cardiaques et les patients diabétiques, tandis qu'avec la PTG, il a été plus élevé chez les patients atteints de maladie hépatique et traités par transfusions sanguines. Les taux de révision chirurgicale ont été plus élevés chez les patients hypertendus et ceux qui souffraient de paraparésie ou d'hémiparésie dans les cas de PTH, et chez les patients atteints de maladies métastatiques dans les cas de PTG. Les facteurs de risque de décès significatifs incluaient maladie métastatique, âge avancé, insuffisance cardiaque, infarctus du myocarde, démence, maladie rhumatismale, maladie rénale, transfusions sanguines et cancer. La présence de comorbidités multiples et l'âge avancé ont été associés à des taux plus élevés de transfusions sanguines et à des séjours hospitaliers plus longs. CONCLUSION: Nous avons déterminé les facteurs de risque associés aux taux plus élevés de complications postopératoires et aux séjours hospitaliers prolongés après une AT. Les résultats permettent d'établir une stratification individualisée des risques dès la consultation préopératoire.

Reductions in Perceived Injustice are Associated With Reductions in Disability and Depressive Symptoms After Total Knee Arthroplasty.

INTRODUCTION: Perceptions of injustice have been associated with problematic recovery outcomes in individuals with a wide range of debilitating pain conditions. It has been suggested that, in patients with chronic pain, perceptions of injustice might arise in response to experiences characterized by illness-related pain severity, depressive symptoms, and disability. If symptoms severity and disability are important contributors to perceived injustice (PI), it follows that interventions that yield reductions in symptom severity and disability should also contribute to reductions in perceptions of injustice. The present study examined the relative contributions of postsurgical reductions in pain severity, depressive symptoms, and disability to the prediction of reductions in perceptions of injustice. METHODS: The study sample consisted of 110 individuals (69 women and 41 men) with osteoarthritis of the knee scheduled for total knee arthroplasty (TKA). Patients completed measures of perceived injustice, depressive symptoms, pain, and disability at their presurgical evaluation, and at 1-year follow-up. RESULTS: The results revealed that reductions in depressive symptoms and disability, but not pain severity, were correlated with reductions in perceived injustice. Regression analyses revealed that reductions in disability and reductions in depressive symptoms contributed modest but significant unique variance to the prediction of postsurgical reductions in perceived injustice. DISCUSSION: The present findings are consistent with current conceptualizations of injustice appraisals that propose a central role for symptom severity and disability as determinants of perceptions of injustice in patients with persistent pain. The results suggest that the inclusion of psychosocial interventions that target depressive symptoms and perceived injustice might augment the impact of rehabilitation programs made available for individuals recovering from TKA.

Intraoperative passive knee kinematics during total knee arthroplasty surgery.

Surgical navigation systems for total knee arthroplasty (TKA) surgery are capable of capturing passive three-dimensional (3D) angular joint movement patterns intraoperatively. Improved understanding of patient-specific knee kinematic changes between pre and post-implant states and their relationship with post-operative function may be important in optimizing TKA outcomes. However, a comprehensive characterization of the variability among patients has yet to be investigated. The objective of this study was to characterize the variability within frontal plane joint movement patterns intraoperatively during a passive knee flexion exercise. Three hundred and forty patients with severe knee osteoarthritis (OA) received a primary TKA using a navigation system. Passive kinematics were captured prior to (pre-implant), and after prosthesis insertion (post-implant). Principal component analysis (PCA) was used to capture characteristic patterns of knee angle kinematics among patients, to identify potential patient subgroups based on these patterns, and to examine the subgroup-specific changes in these patterns between pre- and post-implant states. The first four extracted patterns explained 99.9% of the diversity within the frontal plane angle patterns among the patients. Post-implant, the magnitude of the frontal plane angle shifted toward a neutral mechanical axis in all phenotypes, yet subtle pattern (shape of curvature) features of the pre-implant state persisted.

The role of perceived injustice in the prediction of pain and function after total knee arthroplasty.

Emerging evidence suggests that the appraisal of pain and disability in terms of justice-related themes contributes to adverse pain outcomes. To date, however, research on the relation between perceived injustice and pain outcomes has focused primarily on individuals with musculoskeletal injuries. The primary aim of this study was to investigate the role of perceived injustice in the prediction of pain and disability after total knee arthroplasty (TKA). The study sample consisted of 116 individuals (71 women, 45 men) with osteoarthritis of the knee scheduled for TKA. Participants completed measures of pain severity, physical disability, perceptions of injustice, pain catastrophizing, and fear of movement before surgery, and measures of pain and disability 1 year after surgery. Prospective multivariate analyses revealed that perceived injustice contributed modest but significant unique variance to the prediction of postsurgical pain severity, beyond the variance accounted for by demographic variables, comorbid health conditions, presurgical pain severity, pain catastrophizing, and fear of movement. Pain catastrophizing contributed significant unique variance to the prediction of postsurgical disability. The current findings add to a growing body of evidence supporting the prognostic value of perceived injustice in the prediction of adverse pain outcomes. The results suggest that psychosocial interventions designed to target perceptions of injustice and pain catastrophizing before surgery might contribute to more positive recovery trajectories after TKA.

Changes in the functional flexion axis of the knee before and after total knee arthroplasty using a navigation system.

Long term satisfaction of patients with total knee arthroplasty (TKA) has lagged behind that of total hip arthroplasty. One possible reason is the failure of the artificial joint to recreate natural kinematics of the knee. This study evaluated the pre and post implant functional flexion axis in the knees of 285 total knee arthroplasty patients using a surgical navigation system. Results showed that post-implant there was less femoral rollback early in flexion on the lateral side of the joint than pre-implant. Designing future generations of knee implants to allow for this motion may give patients a more 'natural' feeling knee and may benefit outcomes.

The knee adduction moment during gait is associated with the adduction angle measured during computer-assisted total knee arthroplasty.

Computer-assisted surgery can be used to measure 3-dimensional knee function during arthroplasty surgery; however, it is unknown if the movement of the knee measured during surgery is related to the in vitro, dynamic state of the knee joint, specifically the knee adduction moment during gait, which has been related to implant migration. The purpose of this study was to determine if the preoperative adduction moment is correlated with the knee abduction/adduction angle measured intraoperatively. A statistically significant correlation was found between the mean (r(2) = 0.59; P = .001) and peak (r(2) = 0.53; P = .003) preoperative knee adduction moment and the mean abduction/adduction angle measured intraoperatively. The association found in this study suggests the potential for incorporating functional information that relates to surgical outcome into surgical decision making using computer-assisted surgery.

Continued stabilization of trabecular metal tibial monoblock total knee arthroplasty components at 5 years-measured with radiostereometric analysis.

BACKGROUND AND PURPOSE: The trabecular metal tibial monoblock component (TM) is a relatively new option available for total knee arthroplasty. We have previously reported a large degree of early migration of the trabecular metal component in a subset of patients. These implants all appeared to stabilize at 2 years. We now present 5-year RSA results of the TM and compare them with those of the NexGen Option Stemmed cemented tibial component (Zimmer, Warsaw IN). PATIENTS AND METHODS: 70 patients with osteoarthritis were randomized to receive either the TM implant or the cemented component. RSA examination was done postoperatively and at 6 months, 1 year, 2 years, and 5 years. RSA outcomes were translations, rotations, and maximum total point motion (MTPM) of the components. MTPM values were used to classify implants as "at risk" or "stable". RESULTS: At the 5-year follow-up, 45 patients were available for analysis. There were 27 in the TM group and 18 in the cemented group. MTPM values were similar in the 2 groups (p = 0.9). The TM components had significantly greater subsidence than the cemented components (p = 0.001). The proportion of "at risk" components at 5 years was 2 of 18 in the cemented group and 0 of 27 in the TM group (p = 0.2). INTERPRETATION: In the previous 2-year report, we expressed our uncertainty concerning the long-term stability of the TM implant due to the high initial migration seen in some cases. Here, we report stability of this implant up to 5 years in all cases. The implant appears to achieve solid fixation despite high levels of migration initially.

Minimizing infection risk: fortune favors the prepared mind.

Despite advances in care, infection in total joint arthroplasty remains a serious problem that has yet to be solved. Reported infection rates range from <0.5% in highly specialized centers to a high of 2% as reported at a national level. The epidemiology of total joint arthroplasty remains challenging because of the relatively low, but significant, incidence of infection. Still, there are variables that can be addressed that have demonstrated evidence regarding reduction in infection rates. These variables include optimizing medical conditions in the preoperative period such as anemia, blood glucose, and nutrition. In the perioperative period, administration of parenteral antibiotics within 1 hour of incision is a must. The effect of the operating room environment is less clear, but it is evident that traffic flow in the operating room has a negative effect on infection rates. Skin preparation with chlohexidine is now the agent of choice, and evidence exists that iodophor impregnated occlusive dressings add value. Razors should not be used. Surgical staples for closure have an increased risk of superficial infection as compared to subcuticular sutures. In the postoperative period, early, persistent wound drainage should be managed aggressively. There is no evidence to support the use of parenteral antibiotics past 24 hours in routine cases. Patients should be advised about prophylaxis for infection when undergoing dental work and other high-risk procedures. There is a strong movement to extend this prophylactic period indefinitely, as opposed to 2 years postoperatively. Finally, and perhaps most importantly, it is the surgeon's responsibility to be aware of all these issues and to strongly advocate for patient safety in ensuring that infection risk is minimized.