The increased demand for total hip arthroplasty (THA) is having a significant impact on healthcare resources, resulting in increased interest in outpatient care pathways to reduce resource consumption. This study compared costs between patients who underwent outpatient THA using a Direct Anterior (DA) approach compared to a Direct Lateral (DL) approach to understand the effect of surgical approach on resource use.

We conducted a prospective randomized controlled trial for DA patients undergoing primary THA. We compared patients in the outpatient arm of the trial to a prospective cohort of outpatient DL approach THAs. We recorded all costs including: equipment, length of stay in hospital, and laboratory or other medical tests. Following discharge, participants also completed a self-reported cost diary recording resource utilization such as emergency department visits or subsequent hospitalizations, tests and procedures, consultations or follow-up, healthcare professional services, rehabilitation, use of pain medications, informal care, productivity losses and out of pocket expenditures.

We report costs from both Canadian public health care payer (HCP) and a societal perspective. The HCP perspective includes any direct health costs covered by the publicly funded system. In addition to the health care system costs, the societal perspective also includes additional costs to the patient (e.g. physiotherapy, medication, or assistive devices), as well as any indirect costs such as time off paid employment for patients or caregivers.

We included 127 patients in the DA group (66.6 years old) and 51 patients in the DL group (59.4 years old) (p<0.01).

There were no statistically significant differences in costs between groups from both the healthcare payer (DA= 7910.19, DL= 7847.17, p=0.80) and societal perspectives (DA= 14657.21, DL= 14581.21, p=0.96)

In patients undergoing a successful outpatient hip replacement, surgical approach does not have an effect on cost from in hospital or societal perspectives.

For over a decade, modular titanium fluted tapered (TFT) stems have demonstrated excellent clinical success for femoral revision total hip arthroplasty (THA) surgery. The aim of this study was to report the short-term outcomes of a novel modern monoblock TFT stem used for revision and complex primary THA with a minimum of 2 years follow-up.

We identified 126 patients who received a single monoblock TFT stem - 26 patients for complex THA (failed fracture fixation) and 100 patients for revision THA. The reasons for revision THA included 40 for previous prosthetic joint infection (PJI), 42 for aseptic loosening, 9 for trunnionosis, 9 for periprosthetic fractures. The Paprosky grading for femoral bone loss at the time of surgery and the measured subsidence of femoral stems at 3 months follow-up were determined. We evaluated the number and indications for re-operations.

The mean time from surgery was 3.9 years (range 2.0 to 6.9 years). A paired t-test analysis showed significant improvement from pre-operative versus post-operative clinical outcome scores (p<0.001) for HHS (38.76 +/- 15.24vs. 83.42 +/- 15.38), WOMAC (45.6 ± 19.0 vs. 69.9 ± 21.3) and SF-12 Physical component (31.7 ± 8.1 vs. 37.8 ± 11.3) and SF-12 Mental component (48.2 ± 12.2 vs. 51.6 ± 12.5). The Paprosky grading for femoral bone loss was Grade 1 (3.9%), Grade 2 (35.7%), Grade 3A (47.6%), Grade 3B (11.1%) and Grade 4 (1.6%) cases. There were 18 re-operations (14.7%) with 13 for PJI (7 treated with implant retention, 6 treated with a two-staged revision), 4 for instability and one for acetabular aseptic loosening. There were no aseptic failures of the stem.

This novel modern monoblock TFT stem provided reliable femoral fixation and has increasingly supplanted the use of modular TFT stems for complex primary and revision surgery in our institution.

The Canadian Cardiovascular Society (CCS) recommends performing daily troponin testing on postoperative days 0 through 3 for noncardiac surgical patients to decrease the mortality rate due to myocardial injury. Indications for testing include:

->65 yo

-45-64 yo with significant cardiovascular disease

-a Revised Cardiac Risk Index score (RCRI) > 1

Troponin elevation > 30 ng/L is termed “myocardial injury after noncardiac surgery” (MINS).

The study objective was to determine the prognostic relevance of applying CCS recommendations.

669 patients undergoing THA were included in the study. Based on the CCS recommendation there were 4 patient Groups depending on whether or not they met the MINS screening protocol criteria and whether or not it was applied:

-A - met & applied (n=181)

-B - met & not applied (n=248)

-C – not met & applied (n=10)

-D – not met & not applied (n=230)

307 (45.8%) males and 363 (54.2%) females with an average age of 67.8 years were included. Group A- 24% incidence (43 patients) of troponin rise & 5% incidence (9 patients) of cardiac complications. Group B- 0.4% incidence (1 patient) of cardiac complications.

Groups A + B – representing all patients who should have had the MINS screening protocol applied according to the CCS recommendations − 10 (2.3%) patients developed cardiac complication and one (0.2%) patient death

MINS screening protocol group (A & C) LOS was 4.0 days compared to 1.4 days for those not screened (p-value: <0.001).

Applying the CCS MINS screening protocol to elective THA patients added no benefit in predicting/preventing postoperative cardiac events but was associated with a significant increase in LOS. Following current CCS recommendations without more specifications and clinical evidence is unwarranted.

Introduction

The infection rate after total joint arthroplasty (TJA) has been shown to be 1–2% in multiple series and registry data. Irrigation, debridement, and polyethylene exchange (IDPE) is a common first line treatment in many cases of acute prosthetic joint infection (PJI). The reinfection rate in open IDPE procedures is variable with studies showing reinfection rates of 10–70% depending on various patient and microbial factors. Our pilot study aimed to determine if the bacterial load in infected total joints was sufficiently reduced by IDPE to allow for the use of post-debridement cultures as an independent marker of procedural success.

Purpose

The success of total knee replacement (TKR) surgery can be attributed to improvements in TKR design, instrumentation, and surgical technique. Over a decade ago oxidized zirconium (OxZr) femoral components were introduced as an alternative bearing surface to cobalt-chromium (CoCr), based on strong in-vitro evidence, to improve the longevity of TKR implants. Early reports have demonstrated the clinical success of this material however no long-term comparative studies have demonstrated the superiority of OxZr implants compared to a more traditional CoCr implant. This study aims to compare long-term survivorship and outcomes in OxZr and CoCr femoral components in a single total knee design.

Introduction

The purpose of this study is to estimate the cost-effectiveness of performing total hip arthroplasty (THA) versus nonoperative management (NM) in non-obese (BMI 18.5–24.9), overweight (25–29.9), obese (30–34.9), severely-obese (35–39.9), morbidly-obese (40–49.9), and super-obese (50+) patients.

Purpose

Patient expectations of total knee arthroplasty (TKA) can be managed through education. E-learning is the application of information technology to education. Providing information to patients at the place and time of their choosing, e-learning has the potential to broaden the reach of existing services for patients. This study evaluated whether an e-learning tool could affect whether patients felt their expectations were met and whether they were satisfied with surgery one year following primary TKA.

Purpose

The mobile-bearing total knee arthroplasty was designed to increase the contact area with the polyethylene bearing, through the functional range of motion, and subsequently decrease the wear rate previously seen in fixed-bearing implants. In the literature there is no clear clinical advantage between the different designs in the short to mid-term follow-up.

The purpose of this study was to compare the results between a cruciate retaining mobile-bearing design (SAL II, Sulzer) and two cruciate retaining fixed-bearing designs (AMK, Depuy, and the Genesis II, Smith and Nephew).

Purpose

Unicompartmental versus total knee arthroplasty has been a debated topic for decades. The purpose of this study was to compare the survivorship and clinical outcomes of a large primary total knee arthroplasty versus unicompartmental knee arthroplasty cohort.

Purpose

The pros and cons of general anesthesia versus spinal anesthesia in total hip arthroplasty has been a long debated topic. The purpose of this study was to compare the surgical times, blood loss and transfusion requirements between anesthetic types in patients undergoing primary total hip arthroplasty.

Purpose

The purpose of this study was to compare the outcomes and complications of normal weight, class one obese (BMI=30-34.9 kg/m2) and superobese (BMI≥50 kg/m2) primary total knee replacement (TKR) patients.

Purpose

The patella provides a mechanical advantage to the knee extensor mechanism. Patellectomy, performed for trauma or patellofemoral arthrosis, does not preclude the development of tibiofemoral arthrosis. Total knee arthroplasty is the mainstay of treatment for tibiofemoral arthrosis. The purpose of this study was to evaluate the outcomes of total knee arthoplasty in patients who previously underwent patellectomy.

Purpose: Efforts to decrease polyethylene wear have lead to advances in polyethylene and counter-face technology for total hip replacement. In particular, the use of highly cross-linked polyethylene (XLPE) and more recently, oxidized zirconium (Oxinium) heads, have demonstrated significant in-vitro improvements in THR wear. This study reports on the early clinical performance and wear (measured with RSA) of an randomized controlled trial (RCT) comparing Oxinium and CoCr heads on XLPE and conventional polyethylene (CPE).

Method: Forty patients were enrolled in a RCT and stratified to receive either an Oxinium (Ox) or CoCr head against either XLPE or CPE (ie 10 patients in each group). All patients had otherwise identical THRs and had tantalum beads inserted in the pelvis and polyethylene for wear analysis. There were no significant differences between groups with respect to patient demographics and the average age was 68 years (range 57–76) at index procedure. RSA wear analysis was performed immediately post-op, at six weeks, three and six months and then at one and two years. All patients are a minimum of four years post-op (average 4.6, range 4 – 5.8). Patients were followed prospectively using validated clinical outcome scores (WOMAC, SF-12, Harris Hip scores) and radiographs.

Results: All health-related outcomes were significantly improved from pre-operative with a mean Harris Hip score and WOMAC at last follow-up of 90.9 and 80.2, respectively. Total 3D femoral head penetration at two years for each group were the following: CoCrXLPE (0.068±0.029mm); OxXLPE (0.115±0.038mm); CoCrCPE (0.187±0.079mm); and OxCPE (0.242±0.088mm). Thus, OxCPE was significantly higher than OxXLPE and CoCrXLPE but not CoCrCPE (p=0.001, p> 0.0001 and p=0.094, respectively). In other words, head penetration was higher with CPE compared to XLPE but there was no significant difference between Ox and CoCr heads. Similarily, regardless of head type (ie combining similar poly types), there was a significant difference in 3D head penetration at two years between CPE and XLPE ( CPE 0.213±0.086; XLPE 0.093±0.041, p> 0.0001).

Conclusion: The early results of this RCT, using RSA as the wear analysis tool, indicate a significant improvement in wear with XLPE compared to CPE. However, it failed to show a clear advantage to the use of Oxinium over CoCr against either polyethylene. Longer follow-up is required to determine steady-state wear rates (after bedding-in) and allow comparison between bearing groups.

Purpose: The Genesis II total knee arthroplasty system was introduced in 1996 as the next evolution in TKR design characterized by “built-in” femoral external rotation and improved trochlear design to optimize patellar tracking and femoral/tibial kinematics, as well as a polished tibial base plate and ethylene-oxide sterilized polyethylene to minimize wear. The purpose of this prospective study was to evaluate the long-term (minimum 10 year) clinical and radiographic results and survivorship of this novel TKA implant system.

Method: Between 1996 and 1999, 478 Genesis II Primary TKRs were implanted and followed prospectively in 414 patients (mean follow-up 11.25±1.11 years). Diagnosis at index surgery included: 94% osteoarthritis, 5% inflammatory arthritis, 1% other diagnoses. Average age at index TKR was 68 years (range 38 to 93 years). There were 149 posterior cruciate retaining (31%) and 329 cruciate sacrificing (69%) knees implanted. Patella resurfacing was performed on 89% (432) of the cases. Sixty-seven deaths occurred prior to 10 years follow-up. Patients were followed prospectively using validated clinical outcome scores (WOMAC, SF-12, Knee Society scores) and radiographs. Kaplan-Meier survival analysis was performed.

Results: All health-related outcomes were significantly improved from preoperative with a mean Knee Society Score and WOMAC at last follow-up of 162 and 69, respectively. To date, 16 revision procedures have been performed. Revisions for infection included six two-stage revisions and two cases of irrigation & debridement with polyethylene exchange. In addition, there were three re-operations for stiffness and one for patellar instability. To date, there have been only two revisions for aseptic loosening and/or osteolysis. Excluding revisions for infection, the Kaplan-Meier survivorship analysis of the total knee system was 98.9±0.5% at five years and 98.2±0.6% at 10 years.

Conclusion: The Genesis II total knee arthroplasty system, characterized by “built-in” femoral external rotation, improved trochlear design, a polished tibial base plate and ethylene-oxide sterilized polyethylene, has demonstrated excellent clinical & radiographic results and long-term survivorship (98% at 10 years) at our institution.

Purpose: The range of motion after TKA depends on many patient, surgical technique, and implant factors. Recently, high-flexion designs have been introduced as a means of ensuring or gaining flexion after TKA. We therefore evaluated factors affecting postoperative flexion to determine whether implant design influences long-term flexion.

Method: We prospectively collected data on patients receiving a primary Genesis II total knee replacement with a minimum of 1-year followup (mean, 5.4 years; range, 1–13 years). We recorded pre – and postoperative outcome measures, patient demographics, and implant design (cruciate retaining [CR, n = 160], posterior stabilized [PS, n = 1177], high-flex posterior stabilized [HF-PS, n = 197]).

Results: Backward stepwise linear regression modeling revealed the following factors that significantly affected postoperative flexion: preoperative flexion, gender, body mass index, and implant design. Independent of gender, body mass index, and preoperative flexion, patients who received a HF-PS and PS design implant resulted in 8° and 5° more flexion, respectively, than those who received a CR implant. Based on analysis examining pre-operative flexion categories, patients with low flexion preoperatively (< 100°) were more likely to gain flexion, whereas those with high flexion preoperatively (> 120°) were most likely to maintain or lose flexion postoperatively. Controlling for implant design, patients with high flexion preoperatively (> 120°) were more likely to gain flexion with the HF-PS design implant (HF-PS = 32.0%; PS = 15.1%; CR = 4.5%).

Conclusion: In summary, our data demonstrate postoperative range of motion after TKA is related to several factors, confirming the important role of the patient’s preoperative range of motion. In addition, our review suggests knee design and, in particular, the use of a so called “high-flexion” PS polyethylene design may be advantageous in maintaining or improving flexion postoperatively, especially in those patients with good pre-operative range of motion.

Purpose: A ceramic head coupled to a metal liner is a proposed new alternate bearing in THA. The authors participated in an FDA approved multicentre prospective, randomized, blinded clinical trial comparing ceramic-on-metal (CoM) to metal-on-metal (MoM) in patients receiving a THA.

Method: 390 patients received the same acetabular component and metal insert. 194 patients received a delta ceramic head (CoM) and 196 received a metal head (MoM). Metal ions were evaluated in 72 patients (36-CoM, 36-MoM). Harris Hip scores, radiographs, and metal ion levels (cobalt, chromium and titanium in serum, erythrocytes and urine) were evaluated pre-operatively and at three, 12 and 24 months.

Results: No patients were lost to follow-up. There were no differences between groups’ baseline demographics and clinical scores. At two years there were no differences in Harris Hip scores, radiographs, adverse events or postoperative complications. Both groups had overall very low median metal ion profiles with no statistically significant differences. 24 month MoM vs CoM; Serum cobalt ( g/L), mean: 1.2(+/−0.5) vs 1.1(+/−0.3), median: 0.66(range: 0.2–5.6) vs 1.0 (range: 0.3–2.7); Serum chromium ( g/L), mean: 1.1(+/−0.5) vs 1.4(+/−0.4), median: 0.86(range: 0.3–6.9) vs 1.2(range: 0.3–4.9). Urine cobalt and urine chromium ( g/day) demonstrated similar trends to serum ion levels.

Conclusion: While CoM is a new bearing surface in North America and not currently FDA or HPB approved, it has been in clinical use globally since 2006. Results of this non-inferiority RCT demonstrated no clinical outcome, metal ion, radiographic or adverse event differences between CoM and MoM cohorts.

Purpose: This study develops and validates a technique to quantify polyethylene wear in tibial inserts using micro-computed tomography (micro-CT), a nondestructive high resolution imaging technique that provides detailed images of surface geometry in addition to volumetric measurements.

Method: Six unworn and six wear-simulated Anatomic Modular Knee (DePuy Inc, Warsaw, IN) tibial inserts were evaluated. Each insert was scanned three times using micro-CT at a resolution of 50 μm. The insert surface was reconstructed for each scan through automatic segmentation and the insert volume was calculated. Gravimetric analysis was also performed for all inserts, and the micro-CT and gravimetric volumes were compared to determine accuracy. The utility of surface deviation maps derived from micro-CT was demonstrated by co-registering a worn and unworn insert. 3D deviations were measured continuously across the entire insert surface, including the articular and backside surfaces.

Results: The mean percent volume difference between the micro-CT and gravimetric techniques was 0.04% for the unworn inserts and 0.03% for the worn inserts. No significant difference was found between the micro-CT and gravimetric volumes for the unworn or worn inserts (P = 0.237 and P = 0.135, respectively). The mean coefficient of variation for volume between scans was 0.07% for both unworn and worn inserts. The map of surface deviations between the worn and unworn insert revealed focal deviations exceeding 750 μm due to wear.

Conclusion: Micro-CT provides precise and accurate volumetric measurements of polyethylene tibial inserts. Quantifiable 3D articular and backside surface deviation maps can be created from the detailed geometry provided by the technique. Compared to coordinate mapping, micro-CT provides 10 times greater surface sampling resolution (50 μm vs 500 μm) across the entire insert surface. Micro-CT is a useful analysis tool for wear simulator and retrieval studies of the polyethylene components used in total knee replacement.

Purpose: The purpose of this study was to investigate the mid to long term (minimum 10 years follow-up) survivorship of the AMK total knee arthroplasty (TKA), as well as determine the effect of implant fixation on outcome.

Method: Between 1988 and 2000, 1074 AMK primary total knee arthroplasties were preformed on 843 patients. All diagnosis included, the distribution was 90% osteoarthritis (971), 7% inflammatory arthritis (76) and 3% other diagnoses (27). Average time from surgery was 15 years (range 10–21 years). Average age at primary procedure was 68 years (range 22–99). Fifty-six percent were female (599) and 44% male (475). Preoperative alignment consisted of 56% varus (601) and 17% valgus (182). Ninety percent (968) had patella resurfacing performed, 62% (661) received cemented TKA fixation, on 32% hybrid fixation (cemented femoral component, cementless tibial tray) was performed and 6% (66) had cementless fixation. Two hundred thirty-seven cases were deceased before 20 years follow-up (22%).

Results: At 10 to 21 years follow-up, 129 revisions were performed (12%). The most common reasons for revision were polyethylene wear, particle induced osteolysis, instability and pain (43% of revisions). Implant fixation significantly influenced the rate of revision with cemented fixation having a 6.7% rate of revision (44/661), hybrid fixation a 14% revision rate (47/336) and cementless a 36.4% revision rate (24/66). Excluding infections (11 cases), overall Kaplan-Meier survivorship at five, 10 and 15 years was 96.4%, 91.9% and 85.8%, respectively. At 20 years the predicted Kaplan-Meier survivorship was estimated at 83.5% (no revisions beyond 17.5 years). Cemented fixation was associated with significantly better survivorship than hybrid and cementless fixation (p< 0.0001). At 5, 10 and 15 years cemented AMK TKA survivorship was 97.5%, 94.9% and 91.9% respectively (no revision performed beyond 13.5 years). For hybrid fixation the survival at 5, 10 and 15 years was 97.8%, 92.2% and 85.1% respectively. Cementless AMK THA had a Kaplan-Meier survivor-ship of 88.9%, 78.2% and 57.4% at 5, 10 and 15 years respectively.

Conclusion: Cemented fixation had superior outcomes compared to cementless and hybrid fixation with the most common reasons for revision being polyethylene wear and osteolysis. To our knowledge this the first medium to long term follow-up of the AMK TKA and it demonstrates that method of fixation had a major influence on revision rates and survivorship.

Purpose: Total knee arthroplasty (TKA) is a proven intervention in the management of end-stage knee arthritis. However, the demands of younger, more active patients may result in increased rates of wear and aseptic loosening. The purpose of this study was to assess the long-term outcome of a large cohort of young patients, and to assess if the outcomes of cemented implants differed from non-cemented implants.

Method: Between 1984 and 2003, 350 TKAs were performed in 283 patients who were under 55 years old. Patients were followed a minimum of 5 years. Mean age at time of surgery was 49.0±5.5 years; 64% of patients were female. Primary knee pathologies included degenerative and post-traumatic arthritis (271), inflammatory arthritis (62), and others (17). Multiple implant designs were used; 296 knees were cemented and 54 were non-cemented. The Knee Society Clinical Rating Score (KSCRS) at latest follow-up was calculated. The Kaplan-Meier survivorship was calculated using an endpoint of revision total knee arthroplasty.

Results: Mean follow-up was 8.7±3.4 years. Seventeen knees were revised at a mean of 7.1±4.4 years after the index procedure. Fifteen patients (twenty-five knees) died. Fifty-one patients (sixty-two knees) were lost to follow-up. Sixty patients (sixty-seven knees) had incomplete KSCRS forms. Average function and knee domains of the KSCRS were 70.0±26.7 and 87.3±16.2 respectively. The Kaplan-Meier survival at five, ten, and fifteen years was 0.965±0.011, 0.941±0.015, and 0.933±0.017. The rate of revision was 5.9%. There was no statistically significantly difference observed between the outcomes of cemented and non-cemented implants, male and female patients, or inflammatory versus non-inflammatory arthritis.

Conclusion: This study demonstrates that total knee replacement in younger patients can demonstrate excellent survival rates free of revision. There does not appear to be an obvious survival advantage of cementless designs, or difference in outcomes based on sex of the patient or primary diagnosis of inflammatory or non-inflammatory arthritis.

Purpose: Approximately, 10% of two-stage TKA revisions for deep sepsis become re-infected. The purpose of this study was to determine the success in terms of sepsis eradication and factors associated with failure of repeat two-stage revision TKA.

Method: Between 1991 and 2006, 129 two-stage revision TKRs for deep sepsis were performed. Ten cases which became re-infected were identified. These unfortunate patients, representing 8% of all the two-stage TKA revisions performed during this time period, are the focus of this study. Their progress and treatment interventions were followed for the purposes of this study.

Results: Ten patients were identified with a two-stage revision TKA which became re-infected. Mean patient age was 72 with 40 % being female. Following recurrent sepsis all patients went on to require more than one further two-stage revision (mean 3.67 further revision surgeries). Infection was only successfully eradicated in 28.7% of cases, the remaining require chronic suppressive therapy or have ongoing active infection. Two patients went on to have an arthrodesis (both remain on suppressive anti-biotics) and one patient had trans-femoral amputation. Staph Aureus and Coagulase neg Staph accounted for 80% of primary infective organisms with only one primary infection with methicillin resistant staph aureus (MRSA). Cultures at subsequent revisions were the same organism in 67% cases. Additional organism cultured included Pseudomonas and Propionibacterium. These patients had an increased incidence of multiple medical co-morbidities including Type-2 Diabetes Mellitus and Rheumatoid Arthritis.

Conclusion: Patients with recurrent sepsis after a two-stage revision for infection in TKR all required multiple further surgeries. Eradication of infection was only achieved in 28.7% cases. Risk factors for recurrent sepsis include Rheumatoid Arthritis and Type-2 Diabetes Mellitus.