Primary hip and knee joint replacements in Canada have been estimated to cost over $1.4 billion dollars annually, with revision surgery costing $177 million. The most common cause of revision arthroplasty surgery in Canada is infection. Periprosthetic joint infections (PJIs) are a devastating though preventable complication following arthroplasty. Though variably used, antibiotic laden bone cement (ALBC) has been demonstrated to decrease PJIs following primary total knee arthroplasty (TKA). Unfortunately, ALBC is costlier than regular bone cement (RBC). Therefore, the aim of this study was to determine if the routine use of ALBC in primary TKA surgery is a cost-effective practice from the perspective of the Canadian healthcare system.

A decision tree was constructed using a decision analysis software (TreeAge Software, Williamstown, Massachusetts) to a two-year time horizon comparing primary TKA with either ALBC or RBC from the perspective of a single-payer healthcare system. All costs were in 2020 Canadian dollars. Health utilities were in the form of quality adjusted life years (QALYs). Model inputs for cost were derived from regional and national databases. Health utilities and probability parameters were derived from the latest literature. One-way deterministic sensitivity analysis was performed on all model parameters. The primary outcome of this analysis was an incremental cost-effectiveness ratio (ICER) with a willingness-to-pay (WTP) threshold of $50,000 per QALY.

Primary TKA with ALBC (TKA-ALBC) was found to be more cost-effective compared to primary TKA with RBC (TKA-RBC). More specifically, TKA-ALBC dominated TKA-RBC as it was less costly on the long term ($11,160 vs. $11,118), while providing the same QALY (1.66). The ICER of this cost-utility analysis (CUA) was $-11,049.72 per QALY, much less than the WTP threshold of $50,000 per QALY. The model was sensitive to costs of ALBC-TKA as well as the probability of PJI following ALBC-TKA and RBC-TKA. ALBC ceased to be cost effective once the cost of ALBC was greater than $223.08 CAD per bag of cement.

The routine use of ALBC in primary TKA is a cost-effective practice in the context of the Canadian healthcare system as long as the cost of ALBC is maintained at a reasonable price and the published studies to-date keep supporting the efficacy of ALBC in decreasing PJI following primary TKA. Further, this analysis is very conservative, and ALBC is likely much more cost-effective than presented. This is due to this model's revision surgery cost parameter being based on the average cost of all revision TKA surgery in Canada, regardless of etiology. Considering many PJIs require two-stage revisions, the cost parameter used in this analysis for revision surgery is an underestimate of true cost. Ultimately, this is the first cost-effectiveness study evaluating this topic from the perspective of the Canadian healthcare system and can inform future national guidelines on the subject matter.

Same day home (SDH) discharge in total joint arthroplasty (TJA) has increased in popularity in recent years. The objective of this study was to evaluate the causes and predictors of failed discharges in planned SDH patients.

A consecutive cohort of patients who underwent total knee (TKA) or total hip arthroplasty (THA) that were scheduled for SDH discharge between April 1, 2019 to March 31, 2021 were retrospectively reviewed. Patient demographics, causes of failed discharge, perioperative variables, 30-day readmissions and 6-month reoperation rates were collected. Multivariate regression analysis was undertaken to identify independent predictors of failed discharge.

The cohort consisted of 527 consecutive patients. One hundred and one (19%) patients failed SDH discharge. The leading causes were postoperative hypotension (20%) and patients who were ineligible for the SDH pathway (19%). Two individual surgeons, later operative start time (OR 1.3, 95% CI, 1.15-1.55, p=0.001), ASA class IV (OR 3.4, 95% CI, 1.4-8.2; p=0.006) and undergoing a THA (OR 2.0, 95% CI, 1.2-3.1, p=0.004) were independent predictors of failed SDH discharge. No differences in age, BMI, gender, surgical approach or type of anesthetic were found (p>0.05). The 30-day readmission or 6-month reoperation were similar between groups (p>0.05).

Hypotension and inappropriate patient selection were the leading causes of failed SDH discharge. Significant variability existed between individual surgeons failed discharge rates. Patients undergoing a THA, classified as ASA IV or had a later operative start time were all more likely to fail SDH discharge.

The Accolade®TMZF is a taper-wedge cementless metaphyseal coated femoral stem widely utilized from 2002-2012. In recent years, there have been reports of early catastrophic failure of this implant. Establishing a deeper understanding of the rate and causes of revision in patients who developed aseptic failure in stems with documented concerns about high failure rates is critical. Understanding any potential patient or implant factors which are risk factors for failure is important to inform both clinicians and patients. We propose a study to establish the long-term survival of this stem and analyze patients who underwent aseptic revision to understand the causes and risk factors for failure.

A retrospective review was undertaken of all patients who received a primary total hip arthroplasty with an Accolade® TMZF stem at a high-volume arthroplasty center. The causes and timing of revision surgery were documented and cross referenced with the Canadian Institute of Health Information Discharge Abstract Database to minimize loss to follow-up. Survivorship analysis was performed with use of the Kaplan-Meier curves to determine the overall and aseptic survival rates at final follow-up. Patient and implant factors commonly associated with aseptic failure were extracted and Cox proportional hazards model was used.

A consecutive series of 2609 unilateral primary THA patients implanted with an Accolade®TMZF femoral hip stem were included. Mean time from primary surgery was 12.4 years (range 22 days to 19.5 years). Cumulative survival was 96.1% ± 0.2 at final follow-up. One hundred and seven patients underwent revision surgery with aseptic loosening of the femoral component was the most common cause of aseptic failure in this cohort (33/2609, 1.3%). Younger age and larger femoral head offset were independent risk factors for aseptic failure.

To our knowledge, this is the largest series representing the longest follow-up of this taper-wedge cementless femoral implant. Despite early concerns, the Accolade® TMZF stem has excellent survivorship in this cohort. Trunnionosis as a recognized cause for revision surgery was rare. Younger age and larger femoral head offset were independent risk factors for aseptic failure.

During total knee arthroplasty (TKA), a tourniquet is often used intraoperatively. There are proposed benefits of tourniquet use including shorter duration of surgery, improved surgical field visualization and increased cement penetration which may improve implant longevity. However, there are also cited side effects that include increased post-operative pain, slowed recovery, skin bruising, neurovascular injury and quadriceps weakness. Randomized controlled trials have demonstrated no differences in implant longevity, however they are limited by short follow-up and small sample sizes. The objective of the current study was to evaluate the rates of revision surgery among patients undergoing cemented TKA with or without an intraoperative tourniquet and to understand the causes and risk factors for failure.

A retrospective cohort study was undertaken of all patients who received a primary, cemented TKA at a high-volume arthroplasty centre from January 1999 to December 2010. Patients who underwent surgery without the use of a tourniquet and those who had a tourniquet inflated for the entirety of the case were included. The causes and timing of revision surgery were recorded and cross referenced with the Canadian Institute of Health Information Discharge Abstract Database to reduce the loss to follow-up. Survivorship analysis was performed with the use of Kaplan-Meier curves to determine overall survival rates at final follow-up. A Cox proportional hazards model was utilized to evaluate independent predictors of revision surgery.

Data from 3939 cases of primary cemented TKA were available for analysis. There were 2276 (58%) cases in which a tourniquet was used for the duration of the surgery and 1663 (42%) cases in which a tourniquet was not utilized. Mean time from the primary TKA was 14.7 years (range 0 days - 22.8 years) when censored by death or revision surgery. There were 150 recorded revisions in the entire cohort, with periprosthetic joint infection (n=50) and aseptic loosening (n=41) being the most common causes for revision. The cumulative survival at final follow-up for the tourniquetless group was 93.8% at final follow-up while the cumulative survival at final follow-up for the tourniquet group was 96.9% at final follow-up. Tourniquetless surgery was an independent predictor for all-cause revision with an HR of 1.53 (95% CI 1.1, 2.1, p=0.011). Younger age and male sex were also independent factors for all cause revision.

The results of the current study demonstrate higher all-cause revision rates with tourniquetless surgery in a large cohort of patients undergoing primary cemented TKA. The available literature consists of short-term trials and registry data, which have inherent limitations. Potential causes for increased revision rates in the tourniquetless group include reduced cement penetration, increased intraoperative blood loss and longer surgical. The results of the current study should be taken into consideration, alongside the known risks and benefits of tourniquet use, when considering intraoperative tourniquet use in cemented TKA.

Overall, hip and knee total joint replacement (TJR) patients experience marked benefit, with reported satisfaction rates of greater than 80% with regard to pain relief and improved function. However, many patients experience ‘nuisance’ symptoms, an annoyance which may cause discomfort, which can negatively impact postoperative satisfaction. The purpose of this study was to evaluate the prevalence of nuisance symptoms among TJR patients and impact on overall patient satisfaction.

A prospective survey study to assess type and prevalence of primary hip/knee TJR related nuisance symptoms, and impact on patient satisfaction at six-months to one-year post-TJR was conducted. The survey was administered over a one-year period at one academic arthroplasty centre. Survey questions tapped occurrence of commonly reported nuisance symptoms (e.g. localized pain, swelling, stability, incision appearance/numbness, stiffness, clicking/noise, ability to perform activities of daily living), and impact of the symptom on overall hip/knee satisfaction rated on a 10-point visual analogue scale (VAS), (0=no impact, 10=to a great extent). Overall VAS satisfaction with TJR was also assessed (0=not at all satisfied, 10=extremely satisfied). Survey responses were analysed using descriptive statistics.

The sample comprised of 974 primary TJR patients, including 590 knees (61%) and 384 hips 39%) who underwent surgery over a one-year period. Among knees, the most commonly reported nuisance symptoms and associated impact to satisfaction per mean VAS scores included: difficulty kneeling (78.2%, mean VAS 4.3, ±3.3), limited ability to run or jump (71.6%, VAS 3.3, ±3.3), numbness around incision (46.3%, VAS 3.8, ±3.3), clicking/noise from the knee (44.2%, VAS 2.7, ±2.7) and stiffness (43.3%, 3.3, ±2.7) following knee arthroplasty. Overall, 88.1% of knee patients surveyed experienced at least one self-reported nuisance symptom at one-year postoperative. Mean overall VAS satisfaction with knee TJR was reported as 9/10 (±1.7). Among hip TJR patients, the most commonly reported nuisance symptoms and associated impact to satisfaction per VAS scores were: limited ability to run or jump (68.6%, VAS 3.4, ±3.4), muscular pain in the thigh (44.8%, VAS 3 ±2.7), limp when walking (37.6%, VAS 4.1, ±3.2), hip stiffness (31%, VAS 3.1, ±2.4), and new or worsening low back pain (24.3%, VAS 2.9, ±2.5). Overall, 93.7% of patients experienced at least one self-reported nuisance symptom at one-year postoperative. Mean overall VAS satisfaction following total hip arthroplasty at one year was reported as 8.9/10 (±1.7).

Nuisance symptoms following primary total hip and knee arthroplasty are very common. Despite the high prevalence of such symptoms, impact of individual symptoms to overall TJR satisfaction is minimal and overall TJR patient satisfaction remains high. Careful preoperative counselling regarding the prevalence of such symptoms is prudent and will help establish realistic expectations following primary hip and knee TJR.

Prosthetic joint infections (PJI) are amongst the most feared postoperative complication of total joint replacement (TJR). PJIs are associated with significant morbidity ranging from functional impairment to amputation. Staphylococcus aureus (S. aureus) is one of the most common causative organisms involved in PJI. More than one quarter of the general population are S. aureus carriers, and carrier status has been shown to increase the risk of developing surgical site infections including PJIs. Decolonization of S. aureus carriers prior to surgery has demonstrated promising results in general surgery, however, solid evidence supporting decolonization in orthopaedic patients is lacking. We aimed to seek further evidence supporting pre-operative screening and S. aureus decolonization in patients undergoing primary or revision hip and knee TJR.

A quasi-experimental quality improvement study was conducted to compare the 5-year baseline rates of deep PJIs to a one-year screening and decolonization intervention period. All consecutive patients who underwent primary or revision TJR at one tertiary care hospital in Hamilton, ON, Canada were included in both study periods.

Nasal and throat screening for S. aureus carriage of all eligible TJR patients in the preoperative clinic was implemented as standard of care. Patients who tested positive were contacted and provided with details on the S. aureus decolonization protocol. Decolonization included a standardized treatment protocol of 2% intranasal mupirocin twice daily for five days prior to surgery date (excluding day of surgery), and chlorhexidine gluconate wipes (2%) to be used once daily for 4 days prior to surgery date and on the morning of surgery. Regardless of the colonization status at the visit in the preoperative clinic, all patients were re-swabbed on the day of surgery.

Primary outcome of interest was the rate of deep PJI as per CDC/NHSN at one-year postoperative follow-up. Secondary outcomes included rate of deep PJIs due to S. aureus, adherence to the decolonization protocol, proportion of S. aureus carriers successfully decolonized, and the proportion of patients deemed as non-carriers following preoperative swab subsequently identified as carriers on the day of surgery. A total of 8,505 patients were included in the 5-year control group, and 1,883 during the intervention period, of which 424 (22.5%) were identified as S. aureus carriers.

The deep PJI rate was similar in the two groups, 0.4% (7/1,883) in the intervention group and 0.5% (42/8,505) in the control group (OR 0.75, 95%CI 0.34–1.67, p=0.58). More importantly, we found a significant reduction in PJI due to S. aureus to only one case in the intervention period (0.05%) as compared to 29 cases (0.3%) in the historic control (OR 0.15, 95%CI 0.004–0.94, p=0.0376).

We found a significant reduction in PJIs due to S. aureus by decolonizing S. aureus carriers prior to surgery. However, no significant difference in overall infection rates was observed. In conclusion, routine implementation of active screening for S. aureus and decolonization of carriers before TJR is feasible and helps to reduce PJI due to S. aureus.

The relationship between pain catastrophizing and emotional disorders including anxiety and depression in patients with hip or knee osteoarthritis undergoing total joint replacement (TJR) is an emerging area of study. The purpose of this study was to examine the association between catastrophizing, anxiety, depression and postoperative pain and functional outcomes following primary TJR.

A prospective cohort study of preoperative TJR patients at one academic arthroplasty centre over a one-year period was conducted. Pain catastrophizing was assessed using the Pain Catastrophizing Scale (PCS), and anxiety/depression using the Hospital Anxiety and Depression Scale (HADS-A, HADS-D) at preoperative assessment. Postoperative outcomes at one-year included patient perceived level of hip/knee pain using a visual analogue scale (VAS), subjective perception of function using the Oxford Hip/Knee Scores, and objective function using the Knee Society Score (KSS) and Harris Hip scores (HHS). Median regression was used to assess pattern of relationship between preoperative PCS clinically relevant catastrophizing (CRC), abnormal HADS-A, abnormal HADS-D and postoperative outcomes at one-year. Median difference and 95% confidence interval (CI) were reported. T-tests were performed to determine mean differences in postoperative outcomes among patients with PCS CRC, abnormal HADS-A, and abnormal HADS-D scores versus those with normal scores at preoperative assessment. P-values less than 0.05 were considered statistically significant.

The sample included 463 TJR patients (178 hips, 285 knees). Both the PCS-rumination CRC sub-domain (median difference 1, 95% CI 0.31–1.69, p=0.005) and abnormal HADS-A (median difference 1, 95% CI 0.36–1.64, p=0.002) were identified as significant predictors of one-year VAS pain. PCS-magnification CRC sub-domain was also identified as a significant predictor of KSS/HHS at one-year (median difference 1.3, 95% CI −5.23–0.11, p=0.041). Preoperative VAS pain, Oxford and HHS/KSS scores were significantly inferior in patients who had CRC PCS, abnormal HADS-A, and abnormal HADS-D scores compared to patients with normal scores. At one-year, PCS CRC patients also had significantly inferior VAS pain (p=0.001), Oxford (p < 0 .0001) and KSS/HHS (p=0.025). Abnormal HADS-A and HADS-D patients experienced significantly inferior postoperative VAS pain (HADS-A p=0.025, HADS-D p=0.030), Oxford (HADS-A p=0.001, HADS-D p=0.030), but no difference in KSS/HHS (HADS-A = 0.069, HADS-D = 0.071) compared to patients with normal PCS/HADS scores. However, patients with CRC PCS experienced significantly greater improvement in preoperative to postoperative VAS pain (p < 0 .0001), Oxford (p=0.003) and HHS/KSS (p < 0 .0001). Similarly, patients with abnormal HADS scores showed significant improvement in preoperative to one-year postoperative change scores, as compared to normal patients in VAS pain (HADS-A p=0.011, HADS-D p=0.024), KSS/HHS (HADS-A p=0.017, HADS-D p=0.031), but not Oxford (HADS-A p=0.299, HADS-D p=0.558).

Patients who are anxious, depressed or who pain catastrophize have worse preoperative function and pain. Postoperatively, pain and functional outcomes are also inferior in such patients, however they do experience a significantly greater improvement in outcomes. Furthermore, it appears that rumination and anxiety traits predict pain levels postoperatively. Although these patients report higher levels of pain postoperatively, as compared to preoperative, great improvement can be expected following hip and knee TJR.

The relationship between pain catastrophising and emotional disorders including anxiety and depression in patients with osteoarthritis (OA) undergoing total joint replacement (TJR) is an emerging area of study. The purpose of this study was to examine the association between pain catastrophising, anxiety, depression and preoperative patient characteristics.

A prospective cohort study of preoperative TJR patients at one centre over 12-months was conducted. We examined association between catastrophising, anxiety, depression and preoperative patient characteristics including demographics, pain and function. Pain catastrophising was assessed using the Pain Catastrophising Scale (PCS), and anxiety/depression using the Hospital Anxiety and Depression Scale (HADS-A, HADS-D). Patient perceived level of hip/knee pain was measured using a visual analogue (VAS) pain scale. Patient perception of function was measured using the Oxford Score. Preoperative radiographic grading of OA was determined using the Kellgren and Lawrence (K-L) scale. Logistic regression was used to assess pattern of relationship between preoperative characteristics and PCS or HADS. Adjusted odds ratio (OR) and 95% confidence interval (CI) were reported. A secondary quantile regression analysis examined whether a model not restricted to pre-defined PCS and HADS categories would yield comparable results to the logistic regression model described in the primary analysis. P-values less than 0.05 were considered statistically significant.

The sample included 463 TJR patients (178 hips, 285 knees). VAS pain (OR 1.23,95%CI 1.04–1.45) and Oxford score (OR 1.13,95%CI 1.07–1.20) were identified as significant predictors for PCS. The same two variables were the strong predictors for all sub-domains of PCS excluding rumination. Oxford Score was the only significant predictor for abnormal HADS-A (OR 1.10,95%CI 1.04–1.17) while VAS pain (OR 1.27,95%CI 1.02–1.52) and Oxford (OR 1.09,95%CI 1.01–1.17) were significant predictors for abnormal HADS-D. Similar pattern of association for PCS and HADS was observed in the quantile regression model, where larger VAS pain and Oxford scores significantly increased median PCS across all domains. Female gender, younger age or having a higher ASA grade were associated with higher median HADS-A, but unlike in the logistic regression, this association was statistically significant.

Pain catastrophising and emotional disorders generally result in poor functional outcomes in TJR patients. The most important predictor of catastrophising, anxiety/depression is pain and subjective function. At risk patients include those with high preoperative pain with generally good preoperative function, as well as younger females with significant comorbidities. Such patients should be identified, and targeted psychological therapy implemented preoperatively to optimise coping strategies and adaptive behaviour to mitigate inferior TJR outcomes including pain and patient dissatisfaction.

Purpose: We retrospectively reviewed the pre- and postoperative radiographs of 116 patients receiving primary THA in a high volume arthroplasty centre to evaluate technical causes for limb length discrepancy. We hypothesized that limb lengthening most commonly occurs as a result of low placement of the acetabular implant.

Method: A sample of 116 primary THA’s performed between 2005 and 2007 with complete one-year postoperative clinical outcomes scores and appropriate radiographs available on PACS were identified from a prospective arthroplasty database. Pre- and one-year postoperative AP bilateral hip radiographs were reviewed, and pre- and post-operative leg length discrepancy as well as the respective acetabular and femoral contribution to any postoperative leg length discrepancy (if present) were measured.

Results: We found that 19 THA’s out of 116 (16.4%) were lengthened greater than 8 mm. Mean difference from preoperative to postoperative leg length was 13.3 mm (SD 7.6 mm). A mean of 6.3 mm (SD 6.2 mm) in lengthening was contributed by the femoral stem, and 5.3 mm (SD 6.3 mm) of lengthening was contributed by placement of the acetabular implant (p=0.738). There was a significant correlation between lengthening of the limb and femoral placement of the stem (r=0.5, p< 0.0001). Likewise, there was a strong correlation between limb lengthening and low placement of the cup (r=0.6, p< 0.0001). Of those limbs that were lengthened greater than 8 mm, Oxford Hip Score at one-year post-operative was not correlated with over-lengthening (r=0.06, p=0.551).

Conclusion: These results support our hypothesis that limb lengthening is indeed due to low placement of the acetabular implant, and equally this was attributable to error in placement of the femoral stem. We conclude that with careful preoperative planning and intraoperative identification of the tear drop, a significant reduction in clinically relevant limb lengthening can be achieved.

Purpose: Reducing wait times for total hip (THA) or knee (TKA) joint arthroplasty is a Canadian health care priority. Models that maximise the capacity of advanced practice clinicians (nurses, physical therapists, sports medicine specialists) have been established to streamline care. Hospitals across the Hamilton Niagara Haldimand Brant Local Health Integration Network in Ontario collaborated to establish a Regional Joint Assessment Centre (RJAC). This study was designed to profile patients deemed suitable for surgical review, and to examine wait times for THA or TKA in RJAC patients compared to those referred directly to an orthopaedic surgeon’s office.

Method: Patients referred to the RJAC between July 2007 and August 2008 with knee or hip OA were included. Self-reported function was evaluated using the Oxford Hip and Knee Score that is scored out of 60 (higher scores reflect greater disability). Time to surgery was measured as the number of days from initial review to surgery. Group one consisted of patients that were referred to the RJAC while group two was comprised of patients who were referred directly to a surgeon’s office. Patient characteristics were examined using univariate analyses. Independent t-tests were used to examine between group differences.

Results: One hundred thirty-six patients (mean±sd: 68±2 years, body mass index 31±6 kg/m2, 83 females) with 150 hip and/or knee joint problems were reviewed in the RJAC. Of those, only 33% (45/136 patients) were deemed suitable for surgical review. Self-reported function (Oxford Scores) in the group requiring surgical review was significantly worse (40±7, p=0.03) than in those patients deemed unsuitable for surgical review (37±9). The RJAC group waited on average 130 days for THA and 129 days for TKA (below the provincial target of 182 days) while those referred directly to the surgeons’ offices waited significantly longer (194 days for THA and 206 days for TKA, p< 0.001).

Conclusion: Patients with hip and knee OA who require surgical review have worse self-reported function than those triaged to conservative care. Wait times for THA or TKA were significantly shorter for patients referred to the RJAC under the new model of care than for those referred directly to an orthopaedic surgeon’s office.

Total hip arthroplasty (THA) allows patients to return to an active lifestyle. Unfortunately one of the more common complications of cementless THA is a fracture of the greater trochanter (GT) or the calcar. These may compromise the outcomes of THA, but there are no large studies looking into this hypothesis.

Between September 1998 and August 2005 the Hamilton Arthroplasty group performed 2282 THA operations. Demographic and outcome data on these patients was collected and tabulated in a prospective database. Radiographs were available on a picture archiving system for 1075 of the patients, 85% of which were primary THAs. GT and calcar fractures were identified. Statistical comparisons on the normal distributed outcome data were made using the Student’s T-test comparing repaired and missed fractures.

A total of 60 GT fractures were found in the review of 1075 radiographs, giving an incidence of 5.6%. This included 19 isolated GT fractures and 10 GT fractures with associated calcar fractures that were found in primary hip arthroplasties, 48% of the total. Revision hip surgeries had 14 isolated GT fractures and 17 GT fractures with associated calcar fracture. We found that 23 (40%) of all GT fractures were missed intra-operatively and did not receive any fixation. All calcar fractures were noted and repaired, even if the associated GT fracture was not.

106 isolated calcar fractures were noted, 10% of all arthroplasties, only one of which did not receive fixation. Of this, 85 (80%) were from primary total hip arthroplasty and 21 (20%) from revision hip arthroplasty.

Evaluation of the outcome data showed no significant difference between repaired and missed GT fractures. Reported outcomes compared favourably with the average for all THA in that time period.

Adoption of cementless total hip arthroplasty in North America undoubtedly increases the rate of GT and calcar fractures. Most calcar fractures were noted and fixed but only 50% of GT fractures were discovered intraoperatively, an area of potential improvement. Greater trochanter and recognized calcar fractures may not have long-term detrimental effects.

Purpose: Medical research has classically been based on the male model, this is no different in the design of arthroplasty implants. Focus has recently shifted to gender-specific implant design but evidence is just developing in the literature as to gender specific outcomes. We hypothesised that outcomes in arthroplasty patients are affected by gender.

Methods: Patients were retrospectively identified from a prospectively collected database of total joint arthroplasties performed at one center. Six surgeons performed 1123 primary unilateral cemented TKA’s, and 989 primary unilateral cementless THA’s over a period of seven years. General demographic data was collected along with preoperative and 1-year clinical outcomes including the Harris Hip/Knee Society Score and Oxford Hip/Knee scores. These were compared to determine differences, if any, between males and females using independent samples t-test.

Results: The TKA sample was comprised of 540 (55%) females and 449 (45%) males. The THA sample included 744 (66%) females and 379 (34%) males.

In the TKA group, females were significantly younger, had higher BMI and had differing rates of comorbidities and complications. Female KSS, Oxford and ROM outcomes were significantly inferior to male scores preoperatively and at 1 year follow up. Significantly more females reported higher pain scores than males from pre-op to 1 year. Interestingly, females showed significantly more improvement from pre-op to 1 year in both scores.

In the THR group there were varying rates of complications and comorbidities by gender. Females did significantly worse in the HHS and Oxford hip score from pre-op until one year when results equalized. Similarly pain scores were higher for females preop and at 6 weeks but became equivalent thereafter. Females showed significantly greater improvements from pre-op to 1 year in both outcome scores.

Conclusion: As reported in the literature, results of this study indicate that women choose TJR at a later stage of disease than men do, presenting with inferior functional status. The effect of waiting seems most marked in the knee arthroplasty population with inferior outcomes and pain relief persisting out to 1 year. Surgeons must counsel females differently about expectations and recovery in joint arthroplasty.

Purpose: To determine whether body mass index (BMI) is associated with mis-seating of ceramic acetabular components, and whether any associations are independent of differences in case mix.

Method: All primary total hip arthroplasty (THA) cases using ceramic components, identified from a prospective database of total joint arthroplasties performed at one center among six surgeons between 1998–2006 were radiographically reviewed. The risk of mis-seating by BMI was calculated using logistic regression models.

Results: Of the 411 THAs, 77 (20.3%) were performed in patients with BMIs that were defined as underweight to normal BMI (29.9 BMI). THA mis-seating occurred in 80 cases (19.5%). Intra-operative characteristics differed significantly according to THA mis-seating status. Univariate analysis revealed that THA mis-seating was more likely to occur in procedures performed by certain surgeons (2 trend, p = 0.01) and procedures performed in more recent years (2 trend, p = 0.02). In comparison with patients who did not incur a mis-seated THA, those patients who did incur a mis-seated THA did not have a significantly different trend in BMI (c2 trend, p = 0.09). However, adjustment for case mix, THA type, surgeon and year of procedure revealed a significant association between BMI and risk of THA mis-seating. Those patients who were overweight at the time of THA (BMI of 25.0–29.9) were at increased risk of THA mis-seating (adjusted odds ratio (OR) 2.52, 95% confidence interval (CI) 1.24–5.12, p = 0.01).

Conclusion: THA mis-seating of ceramic acetabular systems was a frequent occurrence. Although incidence of mis-seated THAs did not differ significantly by patient sex, hip side, indication, or THA component type, mis-seating did differ significantly by surgeon and year of replacement. Furthermore, patients who were overweight were more than two times more likely to suffer THA mis-seating than those who were underweight, of normal weight or obese.

Purpose: Medical research has classically been based on the male model, this is no different in the design of arthroplasty implants. Focus has recently shifted to gender-specific implant design but little evidence exists in the literature as to gender specific outcomes. We hypothesized that outcomes in arthroplasty patients are affected by gender.

Method: Patients were retrospectively identified from a prospectively collected database of total joint arthroplasties performed at one center. Six surgeons performed 1123 primary unilateral cemented TKA’s, and 989 primary unilateral cementless THA’s over a period of seven years. General demographic data was collected along with preoperative and 1-year clinical outcomes including the Knee Society (KSS)/Harris Hip Scores (HHS) and Oxford Knee/Hip scores. These were compared to determine differences, if any, between genders using independent samples t-test and chi-square test for proportions.

Results: The TKA sample was comprised of 540 (55%) females and 449 (45%) males. The THA sample included 744 (66%) females and 379 (34%) males. In the TKA group, females were significantly younger, had higher BMI and differing rates of comorbidities and complications. Female KSS, Oxford and flexion outcomes were significantly inferior to male scores pre-operatively and at 1-year follow-up. Significantly more females reported higher pain scores than males from pre-op to one year. Interestingly, females showed significantly more improvement from pre-op to one year in both scores. In the THR group there were varying rates of complications and comorbidities by gender. Females did significantly worse in the HHS and Oxford hip score from pre-op until one year when results equalized. Similarly pain scores were higher for females preop and at 6 weeks but became equivalent thereafter. Females showed significantly greater improvement from pre-op to 1 year for both outcome scores.

Conclusion: As reported in the literature, results of this study indicate that women choose arthroplasty at a later stage of disease than men do, presenting with inferior functional status. The effect of waiting seems most marked in the knee arthroplasty population with inferior outcomes and pain relief persisting out to one year. Surgeons must counsel females differently about expectations and recovery in joint arthroplasty.

The association between obesity and sleep apnea syndrome (SAS) is well known, as is the fact that TJR patients are often obese. Based on review of 5819 primary TJR patients at our institution, 53% of patients presenting for TJR were obese (mean BMI 31), and of those obese patients 61.3% were female. The potential impact of SAS, diagnosed and undiagnosed, on TJR outcomes has not been well described. In the literature it has been suggested that such patients may be at increased risk of prolonged hospital length of stay (LOS), increased risk of postoperative MI, and risk of postoperative respiratory compromise requiring unplanned transfer to a special care unit (SCU). At our institution, unless deemed required for preoperatively identified co-morbidities, all TJR patients are managed acutely on an orthopaedic ward with no formal step down unit available for enhanced monitoring, even when receiving PCA or epidural for postoperative pain control.

We undertook a prospective non-randomised survey of 1927 primary TJR patients over a fifteen-month period to screen for a preoperative diagnosis of SAS, or symptoms suggestive of SAS using the self-report Epworth Sleep Apnea Questionnaire. In addition, we evaluated impact of SAS on LOS, risk of postoperative MI, risk of postoperative respiratory compromise and unplanned transfer to SCU.

Of our sample, 88/1927 patients (4.6%) had a confirmed preoperative diagnosis of SAS. An additional 74/1927 patients (3.8%) had 3/3 symptoms suggestive of undiagnosed SAS. SAS patients were younger; mean sixty-six years, p=0.005, and predominantly male; 58%, p< 0.0001, as compared to non-SAS patients comprised of 60% females and mean age sixty-nine years. Mean BMI was higher in the SAS group; 32.3 versus 30, p< 0.0001. There was no correlation between SAS and risk of postoperative MI, LOS (mean 5.2 days, both groups), nor unplanned SCU admission.

Despite concerns expressed in the literature, we found that SAS, both diagnosed and suspected, was not associated with prolonged LOS, increased risk of postoperative MI, postoperative respiratory compromise, or unplanned postoperative transfer to a SCU.

There were more than 574,000 primary lower limb total joint arthroplasties performed in the United States in 2002 and 48,000 in Canada over approximately the same period. The incidence of clinically apparent myocardial infarction following lower limb arthroplasty has been previously reported at 1.8% (Gandhi et al, 2006). The functional outcome of patients suffering post-operative myocardial infarctions has never been reported to our knowledge. Our hypothesis is that functional scores of patients undergoing total joint arthroplasty that suffer peri-operative myocardial infarction will be lower than in our control patients.

Patients were retrospectively identified from a prospectively collected database of total joint arthroplasties performed at one center. Six surgeons performed 3320 primary lower limb arthroplasties over a period of seven years. Patients of interest were identified via discharge summaries to have suffered a myocardial infarction diagnosed clinically and confirmed by biochemical assay. These patients were then case matched for demographics, risk factors and pre-operative functional score.

Sixty-two patients (twenty six hips and thirty six knees) were identified as having suffered a post-operative myocardial infarction. There was an overall mortality of 13% and only thirty-four of the sixty-two (55%) completed follow-up to one year. The clinical course of the remaining patients remains uncertain. Statistically significant differences have been observed in Oxford hip scores at six weeks post operatively. Any differences disappear by six months. No statistically significant differences in outcomes were seen in knee outcomes.

It would appear that those patients who are well enough to return for follow-up do just as well as those patients who did not suffer myocardial infarctions. There may be some differences in the rate of recovery from the surgery, but it appears that overall functional outcome of the patients that survive remain good.

Controversy exists surrounding best practice for antibiotic prophylaxis in TJR. Practicing orthopedic surgeons performing TJR in Canada were surveyed to inform regarding the most common antibiotic prophylaxis practice.

Cross-sectional survey of five hundred and ninety practicing Canadian orthopaedic surgeons was conducted. Three orthopaedic surgeons, and one infectious disease specialist established face and content validity of the survey. The survey was mailed to surgeons, and re-mailed to non-responders at twelve-weeks. Survey included questions pertaining to prophylaxis indications, antibiotic choice, dosing, route and timing of administration in the primary and revision setting, as well as postoperative wound drainage investigation and management.

Response rate after two mail-outs was 410/590 (69.5%). 96.6% indicated routine use of systemic prophylactic antibiotics for uncomplicated primary TJR. Cefazolin was most commonly prescribed (97.3 %), with 1gm Cefazolin the most common dosage (70.2%). Vancomycin was prescribed 26% of the time as first line. 48.5% administer the antibiotic in the operating suite, and 90% administer within < sixty minutes prior to skin incision. 47.8% routinely use antibiotics in acrylic cement, and 50% use it in a commercially prepared form. Postoperative prophylaxis duration varied widely with 42% preferring twenty-four hours. 33% routinely culture serous wound drainage within one-week postoperative in the absence of redness or fever. 19.8% prescribe antibiotics if wound drainage persists beyond hospital stay. 15.6% would conduct intraoperative wound exploration if drainage persists beyond postoperative day four. 63.9% stated they routinely withhold antibiotics until they have obtained a deep tissue culture specimen in revision TJR. 74% use the same antibiotic prophylaxis regimen for both primary and revision procedures. Of responding surgeons, 47/410 (11.8%) were categorised as high volume performing > two hundred TJR’s per year, and 40/410 (9.8%) were categorised as low volume performing < twenty-five per year. Comparative results to be discussed.

Opinions vary widely amongst surgeons in Canada, illustrating the controversy in what constitutes ‘best practice’. Despite available published data, a large proportion of Canadian surgeons may fall short in meeting optimal standards of care in some domains such as the dose prescribed and timing of administration. This survey also illustrates the lack of available information to guide current management of postoperative wound drainage in the face of shorter patient hospital stays. Much work is needed in this area to determine risks and benefits of these costly tests and interventions in treating arthroplasty patients.

A ligament tensioning device was used during total knee arthroplasty procedures to determine the effective stiffness of the soft tissue envelope around osteoarthritic knees. This information was used to calculate the resting forces on polyethylene components in well balanced knees. Various patient and implant factors were investigated to see if they correlated with the stiffness of the soft tissues around arthritic knees. The effective stiffness of the soft tissues was found to be higher when the posterior cruciate ligament was preserved compared to when it was sacrificed.

The purpose of this study was to determine, in vivo, the effective stiffness of the soft tissue envelope around the knee and to estimate the resting force on the implanted polyethylene component during total knee arthroplasty (TKA). A ligament tensioning device was used to measure displacement between the tibia and the femur versus load during eighty-six consecutive TKA procedures. A maximum of five measurements were made in both flexion and extension. The measurements were taken after bone cuts were made and soft tissue balancing was performed. The effective stiffness of the knee soft tissue envelope was determined in flexion and extension. Post- operative range of motion was measured while the patient was still under anesthetic. There was no significant difference in the average effective stiffness between men and women or between flex-ion and extension. Age did not appear to correlate with effective stiffness. The average effective stiffness was significantly higher in posterior cruciate retaining knees compared to those in which the posterior cruciate was sacrificed. There was no statistical significance between the average resting force on the polyethylene in men versus women, in flexion versus extension, or in posterior cruciate retaining knees versus posterior cruciate sacrificing knees. The immediate post-operative range of motion did not correlate with the resting force on the implanted polyethylene

Retrospective analysis of three hundred and seventy-one obese (BMI _ 30) and two hundred and forty-nine non-obese (BMI < 30) primary unilateral TKA patients with minimum one-year follow-up to determine influence of obesity versus non-obesity on clinical outcomes following primary unilateral total knee arthroplasty (TKA) for osteoarthritis. Obese patients fare just as well as non-obese patients, experiencing a greater degree of improvement in observed and self-reported outcome measures.

Multiple factors determine outcome of TKA. This study aimed to determine influence of obesity versus non-obesity, as measured by body mass index (BMI), on clinical outcomes following primary unilateral total knee arthroplasty (TKA) for osteoarthritis. Compared to non-obese patients, obese patients had inferior preoperative clinical scores, but achieved comparable ultimate clinical outcomes.

Despite inferior preoperative clinical scores, obese patients undergoing primary TKA for osteoarthritis can expect the same ultimate clinical outcome as non-obese patients.

Statistically significant differences for; mean age of obese 69.2 ±9 and non-obese 73±8 (p< 0.0001), with a higher preponderance of obese females, 70.2% vs. 30% male (p=0.033).

Despite statistically significant differences among all preoperative clinical outcomes including; KSS clinical (p=0.019), KSS function (p=0.02), Oxford (p=0.02), and flexion (p=0.001), there were no statistically significant differences among these outcomes at one-year postoperative. No statistical difference among surgical outcomes, hospital length of stay, pain scores or stair climbing ability at any interval.

Retrospective analysis of three hundred and seventy-one obese (BMI _ 30) and two hundred and forty-nine non-obese (BMI < 30) primary unilateral TKA patients with minimum one-year follow-up. Statistical analysis to determine differences in demographics, surgical time, intraoperative complications, hospital length of stay, and clinical outcomes including; flexion, KSS and Oxford score, pain-level and stair climbing ability at six-week, six-month, and one-year postoperative. Patients with previous high tibial osteotomy, ORIF, or receiving associated WSIB benefits were excluded.

Obese patients fare just as well as non-obese patients, experiencing a greater degree of improvement in observed and self-reported outcome measures.

To evaluate the effect of implant articular geometry on postoperative range of motion (ROM) after primary total knee arthroplasty for osteoarthritis, we conducted a retrospective case-control study of one hundred and twenty patients (sixty in each group) comparing Scorpio® Posterior Cruciate Substituting implant using Superflex® versus traditional tibial insert. Cases and controls were matched 1:1 for surgeon and gender. Both groups had similar baseline characteristics. Except for KSS Clinical Score at six months (mean: 92.8 for Superflex® versus 87.6 for traditional insert; p=0.029), there was no statistically significant difference between the two groups in knee scores or ROM up to one-year postoperatively.

To evaluate the effect of implant articular geometry on postoperative range of motion (ROM) after primary TKA.

Despite the advent of high flexion knee designs, surgical technique and patient driven factors remain the overriding determining factors for ultimate flexion range achieved following TKA.

One hundred and twenty patients (sixty in each group) were included. Both groups had similar baseline characteristics. Except for KSS Clinical Score at 6 month (mean ± SD: 92.8 ± 5.8 for Superflex® versus 87.6 ± 14.6 for traditional insert; p=0.029), there was no statistically significant difference between the two groups in knee scores or ROM. Flexion at one year for Superflex® was 113.5° ± 10.5 compared with 113.2° ± 11.9 for traditional tibial insert (p=0.869).

Retrospective cohort study of a prospectively gathered database of TKA’s performed at a high-volume arthroplasty center from 1998 to 2003. Inclusion Criteria: primary TKA for osteoarthritis using Scorpio® Posterior Cruciate Substituting implant with Superflex® tibial insert versus traditional insert. Exclusion Criteria: WSIB, prior history of septic arthritis, and previous knee surgery. Cases and controls were matched 1:1 for surgeon and gender. Postoperative care was standardized. Data points included demographics, operative details, pre- and post-operative Knee Society Score (KSS), Oxford Knee Score and range of motion at six weeks, six months and one year postoperatively. P< 0.05 was considered statistically significant.

Despite improvements in knee prostheses design, patient factors and surgical technique remain the most important determinants of outcome in primary TKA, particularly ROM.