Purpose

With the advent of newer diagnostic imaging tools, the reported prevalence of acute pulmonary embolism (PE) following total hip (THA) and total knee (TKA) arthroplasty appears to be increasing. However, the true prevalence and clinical relevance of these events are unclear. Our study was designed to evaluate the results of routine multi-detector computed tomography (MDCT) in this patient population in the early postoperative period.

Purpose

Although total knee replacement (TKR) has a high reported success rate, the pain relief and functional improvement after surgery varies. We asked what is the prevalence of patients showing no clinically significant improvement 1-year after TKR, and what are the patient level factors that may predict this outcome.

Purpose

Total knee arthroplasty (TKA) is the preferred treatment for those with end stage osteoarthritis (OA) and severe functional limitations. With the demographic transition in society, TKA is being offered to a younger patient population. Younger patients are generally more active requiring an increased range of motion, and place greater physiological demands on the prosthesis than typical older patients. The mobile bearing (MB) total knee prosthesis has theoretically been designed to meet these demands. We conducted a meta-analysis and systematic review of randomized controlled trials comparing outcomes of MB and fixed bearing (FB) TKA.

Purpose: Fractures of the proximal femur are increasing in incidence as the population ages. In order to address this problem the Province of Ontario, Canada (population 14 million) has advocated an integrated model of care.

Method: A policy to improve the outcome for patients sustaining hip fractures has been developed. It has been implemented in the 14 health regions of the province. The objectives are:

All surgical procedures to be performed within 48 hours of patient’s admission to hospital.

Results: Since the implementation of this policy 90% of all hip fracture patients are receiving definitive surgical treatment within 48 hours of admission. Site variations are identified and remedial actions implemented for those hospitals which fail to meet this target. Acute care length of stay following hip fracture has declined from a mean of 17 days to a mean of 8 days. The number of patients with hip fractures returning to their pre-injury residence has increased significantly from approximately 35% to 70% at 3 months post-fracture.

Conclusion: A structured program for hip fracture care can be developed in large population areas and has been implemented for the approximate 10,000 patients sustaining hip fractures annually within our jurisdiction. This model should be broadly applicable to other health regions.

Purpose: Minimally invasive surgery (MIS) knee replacement surgery has experienced a recent surge in popularity, driven by the patient concerns of a faster recovery time and a shorter, more cosmetic scar. However the evaluation of any new medical therapy must include a detailed evaluation of both efficacy and safety outcomes. The primary objective of our meta-analysis was to compare the incidence of complications between minimally invasive(MIS) and standard total knee replacement (TKR) approaches.

Method: We reviewed randomized controlled trials comparing minimally invasive TKR to standard TKR. After testing for publication bias and heterogeneity, the data were aggregated by random-effects modeling. Our primary outcome was the number of complications. Our secondary outcomes were alignment outliers, Knee Society Function Scores, and Knee Society Knee Scores.

Results: We had a total of 9 studies evaluating our primary outcome. Average follow up time ranged from 3 to 28 months. There was no significant publication bias in our study.

The combined odds ratios for complications for the MIS group and alignment outliers were 1.58 (95% CI: 1.01 to 2.47) p< 0.05 and 0.79 (95% CI: 0.34 to 1.82) p=0.58 respectively. The standard difference in means for Knee Society scores was no different between groups.

Conclusion: The results of this meta-analysis demonstrate a statistically significant increase in complication rates with MIS TKR when compared to standard TKR. There were no significant differences in postoperative alignment or KSS at 3 months between the two groups. MIS knee surgery should be approached with caution.

Purpose: Obesity is known to be a risk factor for the incidence and progression of prevalent osteoarthritis (OA). The relationship is traditionally believed to be a mechanical effect on weight bearing joints such as the hip and knee, however studies showing a relationship between body mass index (BMI) and OA of non-weight bearing joints, such as the hand, suggest another theory. They suggest that the relationship between obesity and joint degeneration may be a systemic metabolic effect whereby visceral and sub-cutaneous truncal white adipose tissue (WAT) secrete inflammatory mediators that directly influence the pathogenesis of OA. We asked what is the relationship between adiponectin, leptin, and the A/L ratio and patient reported pain in an end stage knee OA joint population.

Method: We collected demographic data, Short Form McGill Pain scores, WOMAC pain scores, and synovial fluid (SF) samples from 60 consecutive patients with severe knee OA at the time of joint replacement surgery. Synovial fluid samples were analyzed for leptin and adiponectin using specific ELISA. Non-parametric correlations and linear regression modeling were used to identify the relationship between the adipokines and pain levels.

Results: The correlations between the individual adipokines and the pain scales were consistently less than that for the corresponding adipokine ratio. The A/L ratio correlated moderately with the MPQ-SF, (r(58) = − 0.46, p < .01) and the WOMAC pain score, (r(58) = − 0.38, p > .01). Linear regression modeling demonstrated that the A/L ratio was a significant predictor of a greater level of pain on the MPQ-SF(p=0.03, Table 3) but not the WOMAC pain scale(p=0.77, Table 4). Models were adjusted for age, gender, BMI, and medical comorbidity.

Conclusion: In conclusion, a greater A/L ratio predicted lower knee OA pain as measured by the MPQ-SF, but not on the WOMAC pain scale. This finding was above that of the individual adipokine levels alone. Some authors have suggested that leptin may have a proin-flammatory role while adiponectin an anti-inflammatory role in synovial joint diseases. Further work to elucidate these pathways may present a target for novel therapeutics in knee OA.

Purpose: Factors influencing patient willingness to undergo elective surgery are poorly understood.

Method: We prospectively evaluated patient concerns prior to surgical consultation for elective spinal, hip, knee, shoulder/elbow (S/E), or foot/ankle (F/A) conditions. Patients were surveyed for demographic data, SF 36 quality of life (QOL) scores and asked to report their greatest concern about considering surgery for their condition, as well as their willingness to undergo surgery if it was offered to them by their treating surgeon.

Results: In our prospective cohort of 743 patients, 364 (51%) were male and 293 (39 %) were evaluated for a spine condition, 74 (10 %) hip, 192 (26 %) knee, 69 (9 %) S/E, and 115 (16 %) F/A. Mean QOL scores were similar for patients across specialities. The top three greatest concerns for undergoing elective musculoskeletal surgery were potential complications (20%), effectiveness (15%) and recovery time (15%) of surgery. When categorized by specialty, concern of surgical complications was the most prevalent in spine (23%) and F/A patients (30%). However, patients were most commonly unsure of risks associated with their respective subspecialty surgery (spine – 56%; hip – 53%; knee – 44%; S/E – 48% and F/A – 33%). The majority of hip patients (89%) perceived a high success rate for hip surgery, while 65% of spine patients where unsure of the success of spine surgery. Patient willingness to undergo surgery was greatest for hip (84%), knee (78%), and S/E (82%) surgery and least for spine (68%) and F/A surgery (74%).

Conclusion: Although patient willingness to consider surgery is clearly a multifactorial decision, patient perception of surgical risk or success prior to surgical consultation are significant factors.

Purpose: Surgery for degenerative lumbar spinal conditions offers tremendous benefit for patients with moderate/severe symptoms failing non-operative treatment. There is little appreciation among referring family physicians (FPs) on factors that identify the ideal surgical candidate. Differences in preferences between patients and physicians leads to wide variation in referrals and impedes the shared decision-making process. Our purpose was to identify the dominant clinical factors influencing patient, FP, and surgeon preferences for lumbar spinal surgery.

Method: We used conjoint analysis, a rigorous method for eliciting preferences, in a mailed survey to all orthopaedic and neurosurgeons, a random sample of FPs, and patients in Ontario to determine the importance that respondents place on decisions for lumbar spinal surgery. We identified six clinical factors (walking tolerance, duration of pain, pain severity, neurological symptoms, typical onset, and dominant location of pain) and presented 16 hypothetical vignettes to participants who rated, on a six-point-scale, their preference for surgery. Data were analyzed using random-effects ordered probit regression models and relative importance of each clinical factor was reported.

Results: We obtained responses from 131 surgeons, 202 FPs, and 164 patients. We demonstrated that despite wide variations in overall responses, all six clinical factors were highly associated with surgical preference (p< 0.01). Surgeons placed the highest importance on the location of pain (34%), followed by pain severity (19%) and walking tolerance (19%). FPs considered neurological symptoms (23%), walking tolerance (20%), pain severity (20%), and typical onset (16%) to all be of similar importance. Pain severity (29%), walking tolerance (29%), and duration of pain (28%) were the most important factors for patients in deciding for surgery. Orthopaedic (over neurosurgical) specialty was statistically associated with a lower preference for surgery (p< 0.047). Older patient age (p< 0.03) and previous surgical consultation (p< 0.03) were both associated with a greater patient preference for considering surgery.

Conclusion: Different preferences for surgery exist between surgeons, FPs and patients. FPs may reduce over- and under-referrals by appreciating surgeons’ importance on location of pain (leg versus back). Surgeons and FPs may improve the shared decision making process by understanding that patients place high importance on duration, severity, and walking tolerance.

Purpose: The purpose of this study was to determine why some TKR patients are satisfied and others are dissatisfied.

Method: 2,481 primary TKR patients who had completed a decision date WOMAC were randomly identified within the Ontario Joint Replacement Registry (OJRR) database. One year post-operatively, these patients were mailed a survey to determine satisfaction/expectations, willingness to undergo surgery again, Jaeschke self-reported clinical improvement, WOMAC scores and complications. The satisfied and not satisfied patient groups were identified, statistical analysis employed to determine variables that individually affect satisfaction and logistic regression used to identify significant factors which might lead to patient dissatisfaction.

Results: Only 70% of primary TKR patients felt that their expectations had been met and 15% reported that they had no expectations. Only 81% of patients reported that they were satisfied with their TKR. When asked whether they would have their surgery again, 96% of the satisfied patients reported that they would do so as compared to only 63% in the dissatisfied group (p< 0.0001). Using the Jaeschke self-reported clinical improvement scale, 87% of TKR patients reported that they were improved, but only 75% reported that they were a good, great or a very great deal improved. There was a high correlation with the WOMAC change score and the Jaeschke self-reported improvement and willingness to undergo surgery again questions. Significant differences were found between the satisfied and dissatisfied TKR patients in terms of a pre-operative WOMAC score of < 20 (p< 0.004), the WOMAC change score (p< 0.0001), expectations (p< 0.0001), complications (p< 0.0001), age (p< 0.002), referral status (p< 0.0005), living alone (p< 0.01) and comorbidities (p< 0.05). Logistic regression suggested that the most important predictive factors were a pre-operative WOMAC < 20 (p< 004), the WOMAC change score (p< 0.0001), expectations met (p< 0.0001) and complications (p< 0.0001).

Conclusion: Only one in five primary TKR patients are satisfied with their operative procedure. Significant risk factors for patient dissatisfaction after primary TKR include a pre-operative WOMAC < 20, a WOMAC change score of less than 33 points, expectations that were not met or a complication.

Purpose: Synovial fluid (SF) leptin has been shown to have an association with cartilage degeneration. Our objective was to examine the relationship between different measures of body habitus and SF leptin levels in an end stage knee osteoarthritis (OA) population.

Method: Sixty consecutive patients with knee OA were surveyed prior to surgery for demographic data. Body habitus was assessed with the body mass index (BMI), waist circumference (WC) and waist-hip ratio (WHR). SF and serum samples were analyzed for leptin and adiponectin using specific ELISA. Non-parametric correlations and linear regression modeling was used to identify the relationship between the measures of body habitus and SF leptin levels.

Results: Females had greater levels of leptin than males in both the serum and SF. Significant correlations were found between SF leptin levels and BMI and WC (R2 0.44 and 0.38 respectively, p< 0.05). Regression modeling showed that female gender and WC were independent predictors of a greater SF leptin level independent of age, BMI, and presence of diabetes.(p< 0.05)

Conclusion: WC may be a more accurate measure of body habitus than BMI in the relationship between the metabolic effects of adipose tissue and OA.

Purpose: Prophylactic use of antibiotic-laden bone cement (ALBC) has been proposed to decrease the incidence of deep infections. We asked if the use of antibiotic laden bone cement decreased the deep infection rate following primary total knee replacement (TKA) as compared to plain bone cement (PBC).

Method: We surveyed 1,625 consecutive patients undergoing cemented, primary knee replacement with either ALBC or PBC. Relevant covariates including age, body mass index (BMI), gender, education, and medical comorbidity were collected. Joint pain and functional status were assessed at baseline and at 1 year follow up with the respective Western Ontario McMaster University Osteoarthritis Index (WOMAC) scores. The incidence of deep infection at 1 year follow up was recorded.

Results: There were 811 (49.9%) patients in the ALBC group and 814(50.1%) in the PBC group. There were no differences in age, gender, BMI, education or comorbidity between groups at baseline (p> 0.05). We found a deep infection rate of 3.1% in the ALBC group and 2.2% in the PBC group (p=0.27). Adjusted analysis showed that ALBC was not predictive of a lower infection rate at 1 year (p=0.84).

Conclusion: ALBC did not reduce the incidence of deep infection following primary TKA at 1 year follow up. Further studies are needed to define any high risk groups for which ALBC might be beneficial.

Purpose: Metabolic syndrome (MS) is defined as central adiposity, elevated fasting glucose, hypertension, and dyslipidemia defined as high triglyceride and low high-density lipoprotein (HDL) cholesterol. MS is associated with a systemic proinflammatory and prothrombotic state. We asked if patients with MS undergoing total knee arthroplasty (TKA) have an increased risk for symptomatic deep vein thrombosis at 3 months follow-up (DVT).

Method: 1,460 consecutive patients were reviewed from our joint registry undergoing primary, unilateral TKA between the years of 1998–2006. Demographic variables of age, gender, comorbidity, and education were retrieved. Metabolic syndrome (MS) was defined as body mass index above 30 kg/m2, diabetes, hypertension, and hypercholesterolemia. Logistic regression was used to examine the relationship of MS on the incidence of DVT.

Results: The overall incidence of symptomatic DVT was 4.4% (65/1460). Patients with MS had an increased incidence of DVT as compared to those without MS(15.5% vs 3.4%). Adjusted analysis showed that MS increased the risk of symptomatic DVT by 3.2(95% CI [1.0,15.4], p=0.04) times compared to those without MS.

Conclusion: Hospital protocols developed for prophylactic anti-coagulation following TKR should give special consideration to patients with MS.