Prevalence of anemia and association with outcome in joint arthroplasty - is there a difference between primary and revision cases?

PURPOSE: Anemia has been shown to be a modifiable pre-operative, patient factor associated with outcome following arthroplasty. The aims of this retrospective study were to (1) ascertain the prevalence of preoperative anemia in patients undergoing primary and revision hip and knee arthroplasty at a tertiary referral center and (2) to test the association with outcome and whether it differs between primary and revision cases. METHODS: All hip and knee primary and revision arthroplasties performed at a Canadian academic, tertiary-care, arthroplasty center between 2012 and 2017 were included in this study. The study group consisted of 5944 patients, of which 5251 were primary Total Hip and Knee Arthroplasties or Hip Resurfacings and 693 were revision arthroplasties (65% hip revisions/35% knee revisions). Anemia was classified as per WHO definition (hemoglobin < 130 g/L for men and < 120 g/L for women). All anemic patients were grouped into mild, moderate or severe anemia. Length-of-stay, perioperative transfusion-rate, 90-day readmission, overall complication rate and reoperation rates were recorded. The effect of preoperative anemia and the effect of severity of the anemia was evaluated through multivariable regression analysis controlling for relevant covariates. RESULTS: Preoperatively, 15% (786/5251) of the primary patients and 47% (322/693) of the revision arthroplasty patients were anemic preoperatively. Anemic revision patients were 3.1 times more likely (95% CI: 1.47-6.33) to obtain blood transfusions during the hospital stay, compared to a 4.9 times higher risk in primary patients. The odds ratio to sustain any postoperative complication if anemic was 1.5 times higher (95% CI: 0.73-3.16) in revision patients and 1.7 in primary cases. In addition, the 90-day readmission rate among both groups was 1.6 times higher in anemic patients. Furthermore, anemic revision patients had a 5.3 days longer length of stay (95% CI: 2.63-7.91), compared to only 1 additional day in anemic primary patients (95% CI: 0.69-1.34). CONCLUSION: In this study cohort, the prevalence of anemia in patients awaiting revision arthroplasty was 3 times higher (46.6%) than in primary arthroplasty patients (18.7%). Preoperative anemia was associated with similarly, inferior outcomes in both groups. To reduce postoperative complications and the "burden" associated with anemia, these findings strongly recommend optimizing the preoperative hemoglobin in all arthroplasty patients. However, revision patients are affected more frequently, and particular attention must therefore be taken to this growing group in the future. LEVEL OF EVIDENCE: Level III.

Impact of Anesthetic Choice on Time to Discharge for Same-Day Discharge Joints.

BACKGROUND: As total joint arthroplasty programs continue to move towards same-day discharge (SDD), time to discharge is an increasingly important performance indicator. The primary objective of this study was to determine the impact of the choice of anesthetic on the time to discharge after SDD primary hip and knee arthroplasty. METHODS: A retrospective chart review was conducted within our SDD arthroplasty program, with 261 patients identified for analysis. Baseline characteristics, length of surgery, anesthetic drug, dose, and perioperative complications were extracted and recorded. The time from the patient leaving the operating room to physiotherapy assessment and from the operating room to discharge were recorded. These were referred to as ambulation time and discharge time, respectively. RESULTS: The ambulation time was significantly reduced when hypobaric lidocaine was used in a spinal block compared to isobaric or hyperbaric bupivacaine-135 minutes (range, 39 to 286), 305 minutes (range, 46 to 591), and 227 minutes (range, 77 to 387), respectively-(P < .0001). Similarly, the discharge time was also significantly lower with hypobaric lidocaine compared to isobaric bupivacaine, hyperbaric bupivacaine, and general anesthesia-276 minutes (range, 179 to 461), 426 minutes (range, 267 to 623), 375 minutes (range, 221 to 511), and 371 minutes (range, 217 to 570), respectively-(P < .0001). No cases of transient neurologic symptoms were reported. CONCLUSION: Patients receiving a hypobaric lidocaine spinal block experienced significantly reduced ambulation time and time to discharge compared to other anesthetics. Surgical teams should feel confident in using hypobaric lidocaine during spinal anesthesia as it is rapid and efficacious.

The SLIM Study: Economic, Energy, and Waste Savings Through Lowering of Instrumentation Mass in Total Hip Arthroplasty.

BACKGROUND: Nearly 700,000 total hip arthroplasties (THAs) are annually performed in North America, costing the healthcare system >$15 billion and creating over 5 million tons of waste. This study aims to (1) assess satisfaction of current THA setup; (2) determine economic cost, energy cost, and waste cost of current setup and apply lean methodology to improve efficiency; and (3) design and test "Savings through Lowering of Instrumentation Mass (SLIM) setup" based on lean principles and its ability to be safely implemented into practice. METHODS: A Needs Assessment Survey was performed. After review and surgeon input, the "SLIM" set was designed, significantly reducing redundancy. Eighty patients were randomized to either Standard or SLIM setup. Operating room time, blood loss, perioperative adverse events and complications, cost/case, instrument weight (kg/case), total waste (kg/case), case setup time, and number of times and number of extra trays required were compared between groups. RESULTS: The SLIM setup was associated with the following savings: Cost = -$408.19/case; Energy = -7.16 kWh/case; Waste = -1.61 kg/case; Trays = -6 (758 kg/case). No differences in operating room time, blood loss, and complication rate were detected (P > .05) between groups. Setup time was significantly shorter with SLIM (P < .05) and extra instrumentation was opened in <5% of cases. CONCLUSION: A more "minimalist approach" to THA can be safely implemented. The SLIM setup is efficient and has been openly accepted by our allied staff. Such setup can lead to 1,610 kg reduction in waste, 7,160 kWh, and $408,190 in savings per 1,000 THAs performed.

Can We Predict Fracture When Using a Short Cementless Femoral Stem in the Anterior Approach?

BACKGROUND: Short cementless femoral stems may allow for easier insertion with less dissection. The use of short stems with the anterior approach (AA) may be associated with a considerable perioperative fracture risk. Our aim was to evaluate whether patient-specific femoral and pelvic morphology and surgical technique, influence the perioperative fracture risk. Furthermore, we sought to describe important anatomical thresholds alerting surgeons. METHODS: A single-center, multi-surgeon retrospective, case-control matched study was performed. Thirty nine periprosthetic fractures (3.4%) in 1,145 primary AA THAs using short cementless stems were identified. These were matched with 78 THA nonfracture controls for factors known to increase the fracture risk. A radiographic analysis using validated software measured femoral (canal flare index [CFI], morphological cortical index [MCI], and calcar-calcar ratio [CCR]) and pelvic (Ilium-ischial ratio [IIR], ilium overhang, and anterior superior iliac spine [ASIS] to greater trochanter distance) morphologies and surgical techniques (% canal fill). A multivariate and Receiver-Operator Curve (ROC) analysis was used to identify fracture predictors. RESULTS: CFI (3.7 ± 0.6 vs 2.9 ± 0.4, P < .001) and CCR (0.5 ± 0.1 vs 0.4 ± 0.1, P = .006) differed. The mean IIR was higher in fracture cases (3.3 ± 0.6 vs 3.0 ± 0.5, P < .001). Percent canal fill was reduced in fracture cases (82.8 ± 7.6 vs 86.7 ± 6.8, P = .007). Multivariate and ROC analyses revealed a threshold CFI of 3.17 which was predictive of fracture (sensitivity: 84.6%/specificity: 75.6%). The fracture risk was 29 times higher when patients had CFI >3.17 and II ratio >3 (OR: 29.2 95% CI: 9.5-89.9, P < .001). CONCLUSION: Patient-specific anatomical parameters are important predictors of a fracture-risk. A careful radiographic analysis would help identify those at a risk of early fracture using short stems, and alternative stem options should be considered.

Outcomes of Total Hip Arthroplasty After Acetabular Open Reduction and Internal Fixation in the Elderly-Acute vs Delayed Total Hip Arthroplasty.

BACKGROUND: Optimum management for the elderly acetabular fracture remains undefined. Open reduction and internal fixation (ORIF) in this population does not allow early weight-bearing and has an increased risk of failure. This study aimed to define outcomes of total hip arthroplasty (THA) in the setting of an acetabular fracture and compared delayed THA after acetabular ORIF (ORIF delayed THA) and acute fixation and THA (ORIF acute THA). METHODS: All acetabular fractures in patients older than 60 years who underwent ORIF between 2007 and 2018 were reviewed (n = 85). Of those, 14 underwent ORIF only initially and required subsequent THA (ORIF delayed THA). Twelve underwent an acute THA at the time of the ORIF (ORIF acute THA). The ORIF acute THA group was older (81 ± 7 vs 76 ± 8; P < .01) but had no other demographic- or injury-related differences compared with the ORIF delayed THA group. Outcome measures included operative time, length of stay, complications, radiographic assessments (component orientation, leg-length discrepancy, heterotopic ossification), and functional outcomes using the Oxford Hip Score (OHS). RESULTS: Operative time (P = .1) and length of stay (P = .5) for the initial surgical procedure (ORIF only or ORIF THA) were not different between groups. Four patients had a complication and required further surgeries; no difference was seen between groups. Radiographic assessments were similar between groups. The ORIF acute THA group had a significantly better OHS (40.1 ± 3.9) than the ORIF delayed THA group (33.6 ± 8.5) (P = .03). CONCLUSION: In elderly acetabulum fractures, ORIF acute THA compared favorably (a better OHS, single operation/hospital visit, equivalent complications) with ORIF delayed THA. We would thus recommend that in patients with risk factors for failure requiring delayed THA (eg, dome or roof impaction) that ORIF acute THA be strongly considered.

Is There a Role for Preclosure Dilute Betadine Irrigation in the Prevention of Postoperative Infection Following Total Joint Arthroplasty?

BACKGROUND: Conflicting evidence exists surrounding the use of preclosure irrigation solutions in primary total joint arthroplasty (TJA). We aimed to determine the role of dilute betadine lavage in preventing early infection after primary TJA. METHODS: We retrospectively reviewed primary TJAs between 2010 and 2018. Dilute betadine lavage was introduced to our practice in November 2014. We included 3513 total hip arthroplasties, 3932 total knee arthroplasties, and 1033 hip resurfacings (HRs). In group 1 (n = 5588), surgical wounds were irrigated with saline; group 2 used dilute betadine solution (n = 2890). Subanalyses using propensity matching based on known risk factors of infection-age, body mass index, American Society of Anesthesiologists grade, diabetes, and procedure-were completed. RESULTS: There were 48 acute infections in group 1 (0.9%) and 23 in group 2 (0.8%) (P = .762). HR without betadine had the highest acute infection prevalence (P = .028). When groups in the whole cohort were propensity score-matched, group 1 had more acute infections than group 2 (P = .033). The effect of betadine was isolated to HR patients. After excluding HR cases, betadine continued to reduce the acute infection rate when compared with the no betadine group, but this was not statistically significant (0.4% vs 0.8%; P = .101). Likewise, we did not find a significant difference in total hip arthroplasty and total knee arthroplasty patients (P = .796). CONCLUSION: There was a decreased infection rate in the betadine group overall when groups were propensity-matched. Because the reduction in the acute infection rate was clinically significant, we feel this practice is an effective means to prevent infections.

Ten-Year Experience With the Anterior Approach to Total Hip Arthroplasty at a Tertiary Care Center.

BACKGROUND: The anterior approach (AA) to total hip arthroplasty (THA) has advantages for patients and healthcare providers. However, some studies have reported high rates of adverse events when introducing AA-THA. This was not consistent with our center's experience, where 4 senior surgeons safely introduced AA-THA into practice. The purpose of this study is to define the adverse event rates associated with the introduction of AA-THA by a group of experienced surgeons at a single tertiary care center and define experiential factors that may modify adverse event rates. METHODS: Retrospective review of prospectively collected data for an observational cohort of all patients undergoing a THA between 2006 and 2017 was conducted. Four senior surgeons at a single institution operated on 1087 primary elective hips using AA-THA. RESULTS: Between 2006 and 2016, AA-THA rose from 1.5% to 53.2% of annual THA. Adverse events included intraoperative events, early postoperative periprosthetic fractures, dislocation, implant failure, early infection, and wound complications. We observed an overall 90-day adverse event rate of 6.4% (of 1087 hips). The adverse event rate was 41.6% (of 12 hips) in the first 12 months of the study period and 3.6% (of 166 hips) in the final 12 months of the study period reviewed. Sixty hips (5.5%) required a reoperation with or without revision of components, 1 (8.3%) in the first 12 months of the study period and 1 (0.6%) in the final 12 months of the study period. Infection and wound complications were the most common causes of reoperation at 1.8% for all cases (20 hips). Higher rates of adverse events are associated with early procedures (n ≤ 15) for all surgeons but showed no statistically significant impact on 5-year survival rate. CONCLUSION: Our experience demonstrates that AA-THA can be introduced into practice with an acceptable adverse event rate when compared with other approaches to THA. As expected the incidence of adverse events is higher in the early part of the learning curve. Surgeon mentoring in the first 20 cases should be considered to minimize risk of adverse events. LEVEL OF EVIDENCE: Therapeutic Level III.

Does surgical approach influence mid- to long-term patient-reported outcomes after primary total hip replacement? A comparison of the 3 main surgical approaches.

Background: The most effective surgical approach to total hip replacement (THR) remains controversial. Most studies that have compared approaches have reported only short-term outcome data. It is therefore unclear in the literature if a particular surgical approach offers long-term advantages. The aim of this study was to determine the effect of the 3 main surgical approaches to THR on patient-reported outcomes 5 years after surgery. Methods: All patients who underwent a THR for osteoarthritis or osteonecrosis between 2008 and 2012 by an anterior, posterior or lateral approach at The Ottawa Hospital in Ontario, Canada, were included in the study. All preoperative and postoperative scores for the Hip Disability and Osteoarthritis Outcome Score (HOOS) and Western Ontario and MacMaster Universities Osteoarthritis Index (WOMAC) questionnaires were recorded. Analysis of covariance was used to study the relationship between the amount of change in scores on the HOOS and WOMAC subscales (dependent variables) and the surgical approach. The confounding factors of age, sex, American Society of Anesthesiologists (ASA) class, Charnley classification and body mass index were included in the analysis. Results: There were 138 patients (37.6%) in the posterior approach group, 104 (28.3%) in the lateral approach group and 125 (34.1%) in the anterior approach group. There were no significant differences among the 3 groups in terms of Charnley classification, body mass index, sex, ASA class, surgical side and preoperative functional scores. We did not observe any significant differences in the amount of change in the scores for HOOS and WOMAC subscales among the 3 groups. There were also no differences in the final postoperative scores. Conclusion: Our findings suggest that the choice of surgical approach in primary THR surgery without revision has no influence on functional outcomes and quality of life after 5 years. Further studies are needed to assess how patient age and sex may influence the functional outcome of individual surgical approaches.

Contexte: L'approche chirurgicale la plus efficace pour l'arthroplastie totale de la hanche (ATH) n'a pas été déterminée. La plupart des études qui ont comparé les différentes approches n'ont fait état que de données à court terme. Donc, la littérature nous renseigne peu sur leurs bienfaits à long terme. Le but de cette étude est de vérifier l'effet des 3 principales approches chirurgicales pour l'ATH sur les paramètres rapportés par les patients 5 ans après la chirurgie. Méthodes: Tous les patients soumis à une ATH pour arthrose ou ostéonécrose entre 2008 et 2012 par approche antérieure, postérieure ou latérale à l'Hôpital d'Ottawa, en Ontario, au Canada, ont été inclus dans l'étude; et tous les scores préopératoires et postopératoires des questionnaires HOOS (Hip Disability and Osteoarthritis Outcome Score) et WOMAC (Western Ontario and MacMaster Universities Osteoarthritis Index) ont été enregistrés. L'analyse de covariance a servi à étudier le lien entre l'ampleur des changements aux scores des sous-échelles HOOS et WOMAC (variables dépendantes) et l'approche chirurgicale. L'analyse a aussi tenu compte de facteurs de confusion tels que l'âge, le sexe, la classe ASA (American Society of Anesthesiologists), classification de Charnley et indice de masse corporell. Résultats: Le groupe soumis à l'approche postérieure comptait 138 patients (37,6 %), à l'approche latérale 104 (28,3 %) et à l'approche antérieure 125 (34,1 %). Il n'y avait pas de différences significatives entre les 3 groupes aux plans de la classification de Charnley, de l'indice de masse corporelle, du sexe, de la classe ASA, du côté où la chirurgie a été effectuée et des paramètres fonctionnels préopératoires. Nous n'avons observé aucune différence significative quant à l'ampleur du changement aux scores des sous-échelles HOOS et WOMAC entre les 3 groupes; il en est allé de même pour les scores postopératoires finaux. Conclusion: Selon nos observations, le choix de l'approche chirurgicale pour l'ATH primaire sans révision n'exerce aucune influence sur les paramètres fonctionnels et la qualité de vie après 5 ans. Il faudra procéder à d'autres études pour évaluer l'influence potentielle de l'âge et du sexe sur les paramètres fonctionnels des différentes approches.

2018 Frank Stinchfield Award: Spinopelvic Hypermobility Is Associated With an Inferior Outcome After THA: Examining the Effect of Spinal Arthrodesis.

BACKGROUND: Many patients undergo both THA and spinal arthrodesis, and those patients may not fare as well as those who undergo one procedure but not the other. The mechanisms of how spinal arthrodesis affects patient function after THA remain unclear. QUESTIONS/PURPOSES: The aims of our study were to (1) determine how patient-reported outcome measures (PROMs), including the Oxford hip score as well as dislocations and complications compare after THA between patients with and without spinal arthrodesis; (2) characterize sagittal pelvic changes in these patients that occur when moving between different functional positions and test for differences between patients with and without spinal arthrodesis; and (3) assess whether differences in sagittal pelvic dynamics are associated with PROMs, complications, and dislocations after THA. METHODS: In this case-control study, we identified 42 patients (60 hips) who had undergone both THA and spinal arthrodesis between 2002 and 2016 and who were available for followup at a minimum of 12 months (mean, 6 ± 5 years) after the later of the two procedures. These cases were case-control-matched for age, gender, and body mass index with 42 patients (60 hips) who underwent only THA and had no known spinal pathology. All patients completed PROMs, including the Oxford hip score, and underwent four radiographs of the pelvis and spinopelvic complex in three positions (supine, standing, and deep-seated). Cup orientation and various spinopelvic parameters, including pelvic tilt and pelvic-femoral angle, were measured. The difference in pelvic tilt between standing and seated allowed for patient classification based on spinopelvic mobility into normal (± 10°-30°), stiff (< ± 10°) or hypermobile (> ± 30°) groups. RESULTS: Compared with the THA-only group, the THA-spinal arthrodesis group had inferior PROMs (Oxford hip score, 33 ± 10 versus 43 ± 6; p < 0.001) and more surgery-related complications (such as dislocation, loosening, periprosthetic fracture or infection, psoas irritation) (12 versus 3; p = 0.013), especially dislocation (5 versus 0; p = 0.023). We detected no difference in change of pelvic tilt between supine and standing positions between the groups. When standing, patients undergoing THA-spinal arthrodesis had greater pelvic tilt (25° ± 11° versus 17° ± 8°; p < 0.001) and the hip was more extended (193° ± 22° versus 185° ± 30°; p = 0.012). We found that patients undergoing THA-spinal arthrodesis were more likely to have spinopelvic hypermobility (12 of 42 versus three of 42; odds ratio, 5.2; p = 0.02) with anterior tilting of the pelvis. Of all biomechanical parameters, only spinopelvic hypermobility was associated with inferior PROMs (Oxford hip score, 35 ± 9 versus 40 ± 7 in normal mobility; p = 0.049) and was also present in dislocating hips that underwent revision despite acceptable cup orientation. CONCLUSIONS: In patients with spinal arthrodesis who have undergone THA, spinopelvic hypermobility is associated with inferior outcomes, including hip instability. Spinopelvic hypermobility should be routinely assessed because these patients may have a narrow zone of optimum cup orientation that would require new technology to define and assist the surgeon in obtaining it.Level of Evidence Level III, therapeutic study.

Metal on Metal Hip Resurfacing in Patients 45 Years of Age and Younger at Minimum 5-Year Follow-Up.

BACKGROUND: Metal on metal hip resurfacing (MoM-HR) is an alternative to total hip arthroplasty in young and active patients. The purpose was to determine the survivorship of MoM-HR procedures performed in patients aged 45 years and younger assessing patient-reported outcome measures (PROMs) at minimum 5-year follow-up. METHODS: All 217 patients equal to or younger than 45 years of age at the time of surgical intervention presenting to our center with MoM-HR between May 2002 and May 2011 were prospectively followed. Baseline demographic data, preoperative and postoperative radiographic measurements, and validated PROMs were obtained (Hip Disability and Osteoarthritis Outcome Score, Western Ontario and McMaster Universities Osteoarthritis Index, and University of California, Los Angeles Activity Score). Survivorship was calculated using Kaplan-Meier analysis, and risk factors for failure were identified using multivariate regression analysis. RESULTS: The overall survivorship excluding septic failures was 94.6% and 93.8% at 5 and 10 years, respectively. Aseptic loosening of the acetabular component was the most common mode of failure (11/20 cases). Gender, head size, and acetabular abduction angle had no significant effect on survivorship. Significant improvements in PROMs were seen for Hip Disability and Osteoarthritis Outcome Score, Western Ontario and McMaster Universities Osteoarthritis Index, and University of California, Los Angeles Activity Scale (P < .001). CONCLUSION: This study indicates that MoM-HR is a suitable option for young individuals, as demonstrated through improved functional scores and low revision rates. The survivorship of HR in the younger than 45 age-group was similar to that of total hip arthroplasty, as well as HR in older patients. Given the proposed benefits of HR, this procedure may be viewed as a viable option in patients aged younger than 45 years.

A Single-Center Experience With a Titanium Modular Neck Total Hip Arthroplasty.

BACKGROUND: Added modular junction has been associated with implant-related failures. We report our experience with a titanium-titanium modular neck-stem interface to assess complications, possible clinical factors influencing use of neck modularity, and whether modularity reduced the incidence of dislocation. METHODS: A total of 809 total hip arthroplasties completed between 2005 and 2012 from a prospectively collected database were reviewed. The mean follow-up interval was 5.7 years (3.3-10.3 years). Forty-five percent were male (360 of 809), and 55% were female (449 of 809). All stems were uncemented PROFEMUR TL (titanium, flat-tapered, wedge) or PROFEMUR Z (titanium, rectangular, dual-tapered) with a titanium neck. RESULTS: Increased modularity (anteverted/retroverted and anteverted/retroverted varus/valgus (anteverted/retroverted + anteverted/retroverted varus/valgus) was used in 39.4% (135 of 343) of cases using the posterior approach compared with 6.8% (20 of 293) of anterior and 23.7% (41 of 173) of lateral approaches. Four males sustained neck fractures at a mean of 95.5 months (69.3-115.6 months) after primary surgery. Overall dislocation rate was 1.1% (9 of 809). The posterior approach had both the highest utilization of increased modularity and the highest dislocation rate (2.3%), of which the most were recurrent. The anterior (0.3%) and lateral (0%) approaches had lower dislocation rates with no recurrences. CONCLUSION: At a mean 5.7 years, our experience demonstrates a low neck fracture (0.5%) and a low dislocation rate (1.1%). Use of increased modularity may not improve dislocation risk for the posterior approach. Continued surveillance of this group will be necessary to determine long term survivorship of this modular titanium implant.

What Do Reported Learning Curves Mean for Orthopaedic Surgeons?

Practicing orthopaedic surgeons must assess the effects of the learning curve on patient safety and surgical outcomes if a new implant, technique, or approach is being considered; however, it remains unclear how learning curves reported in the literature should be interpreted and to what extent their results can be generalized. Learning curve reports from other surgical specialties and from orthopaedic surgery can be analyzed to identify the strengths and weaknesses of learning curve reporting. Single-surgeon series and registry data can be analyzed to understand learning challenges and to develop a personalized learning plan. Learning curve reports from single-surgeon series have several limitations that result from the limited dataset reported and inconsistencies in the way data are reported. Conversely, learning curve reports from registry data are likely to have greater generalizability, but are largely beneficial retrospectively, after data from a sufficient number of surgeons are assessed. There is a pressing need for surgeons to develop improved and consistent standards for learning curve reporting. Although registry data may provide better prospective measures in the future, the implementation of such registries faces several challenges. Despite substantial limitations, single-surgeon series remain the most effective way for practicing surgeons to assess their learning challenge and develop an appropriate learning plan.

Do patients with a failed metal-on-metal hip implant with a pseudotumor present differences in their peripheral blood lymphocyte subpopulations?

BACKGROUND: Early adverse tissue reactions around metal-on-metal (MoM) hip replacements, especially pseudotumors, are a major concern. Because the causes and pathomechanisms of these pseudotumors remain largely unknown, clinical monitoring of patients with MoM bearings is challenging. QUESTIONS/PURPOSES: The purpose of this study was to compare the lymphocyte subpopulations in peripheral blood from patients with a failed MoM hip implant with and without a pseudotumor and patients with a well-functioning MoM hip implant without a pseudotumor. Potential differences in the systemic immune response are expected to reflect local differences in the periprosthetic tissues. METHODS: Consenting patients who underwent a revision of a failed MoM hip implant at The Ottawa Hospital (TOH) from 2011 to 2014, or presented with a well-functioning MoM hip implant for a postoperative clinical followup at TOH from 2012 to 2013, were recruited for this study, unless they met any of the exclusion criteria (including diagnosed conditions that can affect peripheral blood lymphocyte subpopulations). Patients with a failed implant were divided into two groups: those with a pseudotumor (two hip resurfacings and five total hip arthroplasties [THAs]) and those without a pseudotumor (10 hip resurfacings and two THAs). Patients with a well-functioning MoM hip implant (nine resurfacings and three THAs) at 5 or more years postimplantation and who did not have a pseudotumor as demonstrated sonographically served as the control group. Peripheral blood subpopulations of T cells (specifically T helper [Th] and cytotoxic T [Tc]), B cells, natural killer (NK) cells, memory T and B cells as well as type 1 (expressing interferon-γ) and type 2 (expressing interleukin-4) Th and Tc cells were analyzed by flow cytometry after immunostaining. Serum concentrations of cobalt and chromium were measured by inductively coupled plasma-mass spectrometry. RESULTS: The mean percentages of total memory T cells and, specifically, memory Th and memory Tc cells were lower in patients with a failed MoM hip implant with a pseudotumor than in both patients with a failed implant without a pseudotumor and patients with a well-functioning implant without a pseudotumor (memory Th cells: 29% ± 5% [means ± SD] versus 55% ± 17%, d = 1.8, 95% confidence interval [CI] [1.2, 2.5] and versus 48% ± 14%, d = 1.6, 95% CI [1.0, 2.2], respectively; memory Tc cells: 18% ± 5% versus 45% ± 14%, d = 2.3, 95% CI [1.5, 3.1] and versus 41% ± 12%, d = 2.3, 95% CI [1.5, 3.1], respectively; p < 0.001 in all cases). The mean percentage of memory B cells was also lower in patients with a failed MoM hip implant with a pseudotumor than in patients with a well-functioning implant without a pseudotumor (12% ± 8% versus 29% ± 16%, d = 1.3, 95% CI [0.7, 1.8], p = 0.025). In addition, patients with a failed MoM hip implant with a pseudotumor had overall lower percentages of type 1 Th cells than both patients with a failed implant without a pseudotumor and patients with a well-functioning implant without a pseudotumor (5.5% [4.9%-5.8%] [median with interquartile range] versus 8.7% [6.5%-10.2%], d = 1.4, 95% CI [0.8, 2.0] and versus 9.6% [6.4%-11.1%], d = 1.6, 95% CI [1.0, 2.2], respectively; p ≤ 0.010 in both cases). Finally, serum cobalt concentrations in patients with a failed MoM hip implant with a pseudotumor were overall higher than those in patients with a well-functioning implant without a pseudotumor (5.8 µg/L [2.9-17.0 µg/L] versus 0.9 µg/L [0.6-1.3 µg/L], d = 2.2, 95% CI [1.4, 2.9], p < 0.001). CONCLUSIONS: Overall, results suggest the presence of a type IV hypersensitivity reaction, with a predominance of type 1 Th cells, in patients with a failed MoM hip implant with a pseudotumor. CLINICAL RELEVANCE: The lower percentages of memory T cells (specifically Th and Tc) as well as type 1 Th cells in peripheral blood of patients with a failed MoM hip implant with a pseudotumor could potentially become diagnostic biomarkers for the detection of pseudotumors. Although implant design (hip resurfacing or THA) did not seem to affect the results, as suggested by the scatter of the data with respect to this parameter, future studies with additional patients could include the analysis of implant design in addition to correlations with histological analyses of specific Th subsets in periprosthetic tissues.

Clinical results of the conserve plus metal on metal hip resurfacing: an independent series.

The purpose of the present study was to report the clinical and radiographic results of an independent series of the Conserve Plus hip resurfacing. Five hundred forty-eight consecutive hip resurfacings were performed using the Conserve Plus prosthesis in 458 patients (350 males) with a mean age of 48.3 years (range 19 to 66). No patients were lost to follow-up. At a mean follow-up of 6.6 years (3.9 to 11.9) thirty (5.4%) hips required conversion to a total hip arthroplasty (THA) (20 males, 10 females, mean age=48.3±7.3 years). Five-year survival with as revision endpoint was 94.5% (95% CI: 93.5% to 95.5%). This study confirms the good clinical results previously reported with the Conserve Plus hip resurfacing device.

Proximal femoral arthroplasty in patients undergoing revision hip arthroplasty.

Bone loss represents one of the greatest challenges in revision joint surgery. A retrospective review was conducted of both radiographic and clinical outcomes of eleven patients who underwent revision arthroplasty using a long extensively porous coated cylindrical femoral component. All patients' femurs presented with severe proximal femoral bone loss (Paprosky class IIIB and IV). With a mean follow-up of 8 years (2 to 14) we report no femoral revisions and one acetabular revision to a constrained cup secondary to instability. All patients were clinically and radiographically stable. We did not observe any issue with proximal stress shielding or component loosening. The article reports that in patients with severe proximal femoral bone loss, extensively porous-coated non-modular stems are a viable option offering stable and predictable outcomes.

Repeated early failure of a newly designed hinged knee system.

We report a case of acute and recurrent accelerated wear of the polyethylene bushings of the hinge mechanism in the Zimmer Segmental Knee System. This resulted in an unacceptable recurvatum deformity leading to multiple revision knee operations, which was unexpected in a modern design hinged knee system. A custom modification of the original design was used to prevent further recurvatum deformity. The current design of the hinge post mechanism in this system appears to be inadequate, which led to the development of a significant recurvatum deformity in our patient. Surgeons should be aware of this potential complication when considering the use of this revision knee system.

Accuracy of digital templating in uncemented primary total hip arthroplasty: which factors are associated with accuracy of preoperative planning?

BACKGROUND: Preoperative planning is a fundamental step for successful total hip arthroplasty (THA). Studies have highlighted the accuracy of preoperative digital templating for estimating acetabular cup and stem size. Stem design such as single-wedge metadiaphyseal (Type 1 stem) versus mid-short stem (microplasty) and surgical approach (anterior, direct lateral or posterior) have not been well investigated as predictors of THA templating accuracy. METHODS: 204 patients (220 hips) who had undergone elective THA between November 2016 and December 2019 and presented a saved preoperative template were retrospectively reviewed. Templates from 5 different surgeons were involved in the analysis. 3 different approaches were used: direct lateral (DL), posterior (PA), direct anterior (DAA). 2 different stem designs were used: single-wedge metadiaphyseal and single-wedge mid-short (Biomet Taperloc Microplasty), while the acetabular component remained the same. Bivariate and multivariate regression analyses were performed to determine predictors of accuracy. RESULTS: Femoral component size templating accuracy was significantly improved when using the single-wedge mid-short stem (Taperloc Microplasty) design when performing bivariate analysis. Although accuracy of cup sizing was not affected by approach, precision was significantly better in the PA group (p < 0.05). Accuracy of templating was found to be independent of BMI and gender but dependent on presence of calibration marker and stem design (p < 0.05). CONCLUSIONS: When striving for improved templating accuracy, acetabular and femoral component accuracy were best achieved using a calibration marker and a metaphyseal short femoral stem design.

The direct anterior approach is safe and shortens hospital length of stay following hemiarthroplasty for neck of femur fracture.

OBJECTIVE: To investigate the safety of using the anterior approach (AA), compared to the lateral approach (LA), in hemiarthroplasty for the treatment of displaced neck of femur fractures. DESIGN: Retrospective case-control match cohort study. SETTING: Level 1 trauma center. PATIENTS: Retrospective review of prospectively collected data for 39 consecutive intracapsular hip fractures treated with hemiarthroplasty using an AA between 2017 and 2021. Patients operated with the AA were matched in 1:2 ratio with patients that had hemiarthroplasty via a LA. MAIN OUTCOME MEASURES: Discharge destination, 90-day emergency room (ER) visit or readmission rate, inpatient and 90-day mortality rate, inpatient medical complications, 90-day mechanical complications, 90-day reoperation, and length of hospital stay (LOS). RESULTS: Discharge destination (p = 0.695), 90-day ER visit or readmission rate (p = 0.315), inpatient (p = 0.719) and 90-day mortality rate (p = 0.815), medical complications (p = 0.524), mechanical complications (p = 0.150) were similar between cohorts. Five patients, all in the LA-group, required re-operations within 90-days (p = 0.106). Patients in AA-group had shorter LOS (9.3 days, 95% CI [7.6-11.1] vs. 14.7 days [95% CI 12.2-17.3], p = 0.002). CONCLUSIONS: The AA can be safely introduced for the treatment of hip fractures. Similar short-term outcomes relative to the LA were identified. The shorter LOS may reflect the improved early functional recovery offered from the muscle-sparing AA technique. Future, level-1 data should include early- and longer term functional outcome along with cost-effectiveness.

High incidence of migration with poor initial fixation of the Accolade stem.

BACKGROUND: Numerous cementless femoral stem design variations are in clinical use. Because initial implant instability and micromotion are associated with aseptic loosening of the femoral component, migration analysis provides an early assessment of implant survivorship. QUESTIONS/PURPOSES: We determined the (1) migration pattern of the Accolade cementless femoral stem; (2) clinical factors predisposing to stem migration; (3) self-reported patient outcomes; and (4) our current rate of aseptic stem loosening. METHODS: We retrospectively analyzed 81 femoral stems for aseptic migration using Ein-Bild-Roentgen-Analyse-femoral component analysis. Postoperatively, patients completed the WOMAC and SF-12 questionnaires. We assessed radiographic factors potentially associated with subsidence: indices of bone shape and quality, canal fill of the implant, and radiographic signs of loosening. Minimum followup was 24 months (mean, 29 months; range, 24-48 months). RESULTS: The average subsidence at 24 months was 1.3 mm (range, 0-1.5 mm). In the first 2 years, 36% of stems subsided more than 1.5 mm. Large stem size was associated with subsidence. Radiolucent lines (> 1.5 mm in three zones) were present in 10% of stems and associated with lower questionnaire scores. The 5-year survivorship for aseptic loosening of the 367 stems was 97% with revision as end point and 95% for radiographic failure. CONCLUSIONS: The high incidence of migration and stems with radiographic failure raises concerns about patient clinical function and long-term survivorship of this stem design. This migration pattern may be due to poor initial stability with a subsequent lack of osseointegration. Our results differ from radiographic findings and clinical durability of other similar cementless stem designs. LEVEL OF EVIDENCE: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.