Aims

Elevated blood cobalt levels secondary to metal-on-metal (MoM) hip arthroplasties are a suggested risk factor for developing cardiovascular complications including cardiomyopathy. Clinical studies assessing patients with MoM hips using left ventricular ejection fraction (LVEF) have found conflicting evidence of cobalt-induced cardiomyopathy. Global longitudinal strain (GLS) is an echocardiography measurement known to be more sensitive than LVEF when diagnosing early cardiomyopathies. The extent of cardiovascular injury, as measured by GLS, in patients with elevated blood cobalt levels has not previously been examined.

Elevated blood cobalt secondary to metal-on-metal (MoM) hip arthroplasties has been shown to be a risk factor for developing cardiovascular complications including cardiomyopathy. Published case reports document cardiomyopathy in patients with blood cobalt levels as low as 13µg/l. Clinical studies have found conflicting evidence of cobalt-induced cardiomyopathy in patients with MoM hips. The extent of cardiovascular injury, measured by global longitudinal strain (GLS), in patients with elevated blood cobalt levels has not previously been examined.

Sixteen patients with prospectively collected blood cobalt ion levels above 13µg/l were identified and matched with eight patients awaiting hip arthroplasty with no history of cobalt implants. Patients underwent echocardiogram assessment including GLS.

Patients with MoM hip arthroplasties had a mean blood cobalt level of 29µg/l compared to 0.01µg/l in the control group. There was no difference or correlation in EF, left ventricular (LV) end systolic dimension, LV end diastolic dimension, fractional shortening, ventricular wall thickness or E/e’ ratio. However, GLS was significantly reduced in patients with MoM hip arthroplasties compared to those without (−15.2% v −18%, (MoM v control) p= 0.0125). Pearson correlation demonstrated that GLS is significantly correlated with blood cobalt level (r= 0.8742, p=0.0009).

For the first time, this study has demonstrated reduced cardiac function in the presence of normal EF as assessed by GLS in patients with elevated cobalt above 13µg/l. As GLS is a more sensitive measure of systolic function than EF, routine echocardiogram assessment including GLS should be performed in all patients with MoM hip arthroplasties and elevated blood cobalt.

Arthroscopic hip procedures have increased dramatically over the last decade as equipment and techniques have improved. Patients who require hip arthroscopy for femoroacetabular impingement on occasion require surgery on the contralateral hip. Previous studies have found that younger age of presentation and lower Charlson comorbidity index have higher risk for requiring surgery on the contralateral hip but have not found correlation to anatomic variables. The purpose of this study is to evaluate the factors that predispose a patient to requiring subsequent hip arthroscopy on the contralateral hip.

This is an IRB-approved, single surgeon retrospective cohort study from an academic, tertiary referral centre. A chart review was conducted on 310 primary hip arthroscopy procedures from 2009-2020. We identified 62 cases that went on to have a hip arthroscopy on the contralateral side. The bilateral hip arthroscopy cohort was compared to unilateral cohort for sex, age, BMI, pre-op alpha angle and centre edge angle measured on AP pelvis XRay, femoral torsion, traction time, skin to skin time, Tonnis grade, intra-op labral or chondral defect. A p-value <0.05 was deemed significant.

Of the 62 patients that required contralateral hip arthroscopy, the average age was 32.7 compared with 37.8 in the unilateral cohort (p = 0.01) and BMI was lower in the bilateral cohort (26.2) compared to the unilateral cohort (27.6) (p=0.04). The average alpha angle was 76.3⁰ in the bilateral compared to 66⁰ in the unilateral cohort (p = 0.01). Skin to skin time was longer in cases in which a contralateral surgery was performed (106.3 mins vs 86.4 mins) (p=0.01). Interestingly, 50 male patients required contralateral hip arthroscopy compared to 12 female patients (p=0.01). No other variables were statistically significant.

In conclusion, this study does re-enforce existing literature by stating that younger patients are more likely to require contralateral hip arthroscopy. This may be due to the fact that these patients require increased range of motion from the hip joint to perform activities such as sports where as older patients may not need the same amount of range of motion to perform their activities. Significantly higher alpha angles were noted in patients requiring contralateral hip arthroscopy, which has not been shown in previous literature. This helps to explain that larger CAM deformities will likely require contralateral hip arthroscopy because these patients likely impinge more during simple activities of daily living. Contralateral hip arthroscopy is also more common in male patients who typically have a larger CAM deformity. In summary, this study will help to risk stratify patients who will likely require contralateral hip arthroscopy and should be a discussion point during pre-operative counseling. That offering early subsequent or simultaneous hip arthroscopy in young male patients with large CAMs should be offered when symptoms are mild.

Although the impact of sexual difficulties on quality of life in patients with hip osteoarthritis has been documented in previous literature, recent research has shown that surgeons rarely discuss this sensitive topic with patients. The purpose of this study was to develop an educational tool to address common questions that patients may have regarding returning to sexual activity following their total hip arthroplasty (THA).

The study was conducted in two phases. In Phase 1, patients who underwent a THA between 2013–2017 at a single centre were retrospectively identified and sent an anonymous online survey. This survey was aimed at assessing patient-specific concerns regarding whether they would have liked to receive information about returning to sexual activity, what information they would have liked to know and how they would have liked to receive this information. An educational tool was developed based on the findings of Phase 1. In Phase 2, prospective patients who were scheduled for a unilateral or bilateral THA were provided with the educational tool prior to their surgery. A questionnaire was administered to evaluate the effectiveness of this educational tool. Descriptive statistics and chi-squared tests were used for data analysis.

In Phase 1, the overall response rate was 34.7% (n = 58/167). Out of the total respondents, 51.7% indicated an interest in receiving information on when to return to sexual activity following a THA. Patients selected an informational pamphlet as the most desired method of receiving information (p = .044). In Phase 2, the response rate was 54.5% (n = 30/55). Overall, 90% of patients felt that the pamphlet addressed all their concerns, and 93.3% felt they were provided with adequate information on how they could get more information. The pamphlet addressed questions regarding when it was safe to resume sexual activity following a THA, what positions were safe, and the associated risks.

Individuals undergoing a THA are modestly interested in receiving information regarding when to return to sexual activity following their surgery, especially those who are sexually active preoperatively. This educational pamphlet may be useful in routine clinical practice in addressing concerns regarding returning to sexual activity. Understanding patients' goals and expectations for their postoperative course may help surgeons provide a more comprehensive approach to patient care.

Necrotizing Fasciitis (NF) is a life-threatening infectious condition which requires expedient diagnosis to proceed with urgent surgical debridement. However, it can be difficult to establish an early diagnosis and expedite operative management as signs and symptoms are often non-specific and may mimic other pathology. Scoring systems such as The Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) have been proposed to incorporate laboratory findings to predict whether a soft tissue infection is likely to be NF. Recent studies have found the sensitivity and specificity of the LRINEC tool to be lower than originally cited by the LRINEC authors in a validation cohort. Furthermore, there seems to be a predilection for certain geographic locations of patients with NF transferred to our tertiary care center for management, however, to our knowledge, geographic risk factors for NF have not been reported. This study also aims to determine the morbidity and mortality rate of NF at our Canadian tertiary hospital in recent years.

Comorbidities such as smoking, diabetes, and steroid use will be analyzed for any correlation with developing NF. Identification of patient factors in correlation with laboratory values may help identify patients at higher risk for having NF upon their presentation to the emergency department. A resultant earlier diagnosis of necrotizing soft tissue infections would allow for earlier surgical debridement and positively influence patient outcomes.

A retrospective chart review of 125 cases of NF at Kingston Health Sciences Centre from 2005 to 2017 was carried out to assess the validity of the LRINEC in our population and to examine the effect of comorbid factors such as smoking, diabetes, and corticosteroid use on the development of NF. The study cohort included patients treated by all surgical disciplines at our institution over twelve years. A separate cohort of 125 cellulitis or abscess cases was analyzed to assess the validity of the LRINEC tool in differentiating necrotizing fasciitis from non-necrotizing infections such as cellulitis and soft tissue abscess.

The 30-day mortality rate of NF treated at our institution during the study period was 21%. Advanced age was found to be a significant risk factor for death within 30 days of diagnosis (p=0.001). Smoking and steroid use were both found to increase risk for developing NF (p=0.01 and p=0.03, respectively). Diabetes did not appear to increase risk NF. There was no statistical difference in mortality rates between males and females with NF. The sensitivity of LRINEC in detecting NF was only 47% with a specificity of 74%.

The mortality rate of NF at our center is similar to that of other countries in recent years. Males and females have nearly equal mortality rates from NF. Smoking and steroid use appear to increase risk for developing NF, while diabetes may not. The LRINEC assessment tool alone may underestimate risk for developing NF, however, use of other clinical factors such as comorbidity analysis will further aide in the diagnosis of NF allowing for earlier surgical debridement.

Purpose

Prospective randomized intervention trial to determine whether patients undergoing rotating platform total knee arthroplasty have better clinical outcomes at two years when compared to patients receiving fixed bearing total knee arthroplasty as measured by the WOMAC, SF-36 and Knee Society (KSS) scores.

Successful total knee arthroplasty design is related to the joint dynamics imposed by the design. This study examined the clinical and biomechanical performance of patients who received a PFC Sigma total knee implant (posterior cruciate substituting design). Radiographic, strength testing, gait pattern and clinical survey data were collected. Pre-operative and post-operative outcome measures were compared. Statistically significant differences were found on the pain, stiffness and physical function scales of the WOMAC as well as the knee and total score parameters of the Knee Society Score. Significant improvements were also seen on several gait pattern parameters.

Factors such as implant design and surgical technique have been found to influence knee kinematics and kinetics thereby effecting patient function and implant survival after total knee arthroplasty. Numerous gait studies have reported a lack of normal gait pattern for TKA patients (Wilson et al., 1996; Andriacchi, 1993; Jevsevar et al., 1993). There is debate in the literature as to which design best improves patient function and implant survival, the posterior cruciate (PC) substituting or PC-retaining. The purpose of this study is to determine the clinical outcome and biomechanical performance of patients who receive PFC Sigma total knee arthroplasty.

The PC substituting implant design provided significant improvements in clinical and gait outcomes at two years post-op in this patient sample.

Patients experience significant pain and stiffness relief, and better functional outcomes.

A cohort of eighteen total knee replacement patients were followed for two years post-operatively. Radiographic, strength testing, gait pattern and clinical survey data (SF36, WOMAC, Knee Society Score) were collected. Paired sample t-tests, repeated measures general linear modeling and principle component analyses comparing aged matched normals were conducted to evaluate pre-operative and post-operative outcomes. Statistically significant differences were found on the pain, stiffness and physical function scales of the WOMAC as well as the knee and total score parameters of the Knee Society survey. There were also significant improvements found on gait pattern parameters. Findings like these point to a need for larger population studies of patients with PC-substituting TKA.

Funding: Funding for this study was provided by Depuy Orthopaedics, Inc.