Purpose

To review prospectively collected data on patients undergoing primary total hip arthroplasty utilizing two different cementless acetabular components.

Purpose

The purpose of the study was to determine the rate of conversion from RSA to THR in a number of Canadian centers performing resurfacings

Purpose

Cross-linking of polyethylene greatly reduces its wear rate in hip simulator studies. We conducted a systematic review and meta-analysis of randomized controlled trials comparing cross-linked to conventional polyethylene liners for total hip arthroplasty to determine if there is a clinical reduction of: 1) wear rates, 2) radiographic osteolysis, and 3) need for total hip revision.

Purpose

Displaced midshaft clavicular fractures are a common injury with a high occurrence rate in young, active individuals. Non-operative care has traditionally been the standard of care for such fractures, but more recent studies have suggested benefits following primary operative fixation. The purpose of this study was to review the literature on displaced midshaft clavicle fractures, identify randomized controlled trials of operative versus non-operative treatment, and pool the functional outcome and complication rates (including nonunion and symptomatic malunion), to arrive at summary estimates of these outcomes.

Purpose

Angiogenesis and osteogenesis are essential for bone growth, fracture repair, and bone remodeling. VEGF has an important role in bone repair by promoting angiogenesis and osteogenesis. In our previous study, endothelial progenitor cells (EPCs) promoted bone healing in a rat segmental bone defect as confirmed by radiological, histological and microCT evaluations (Atesok, Li, Schemitsch 2010); EPC treatment of fractures resulted in a significantly higher strength by biomechanical examination (Li, Schemitsch 2010). In addition, cell-based VEGF gene transfer has been effective in the treatment of segmental bone defects in a rabbit model (Li, Schemitsch et al 2009); Purpose of this study: Evaluation of VEGF gene expression after EPC local therapy for a rat segmental bone defect.

Purpose

Femoral shaft fractures are routinely treated using antegrade intramedullary nailing under fluoroscopic guidance. Malreduction is common and can be due to multiple factors. Correct entry point identification can help minimize malreduction and the risk of iatrogenic fracture. This study aims to compare landmark identification used to guide nail entry, the piriformis fossa (PF) and the trochanteric tip (T), via computer navigation and conventional fluoroscopy.

Purpose

Femoroacetabular impingement (FAI) may contribute to the development of early onset hip osteoarthritis (OA). A cam lesion (or pistol grip deformity) of the proximal femur reduces head-neck offset resulting in cam type FAI. The alpha angle is a radiographic measurement recommended for diagnosis of cam type FAI. The purpose of this study was to determine if patients that develop end stage hip OA prior to 55 years of age have radiographic evidence of cam type FAI.

Purpose

The SPRINT trial randomized 1226 patients with tibial shaft fractures treated by intramedullary (IM) nailing to reamed versus unreamed groups. Using data from this trial, we completed a subgroup analysis of those patients who required two or more reoperations following the initial IM fracture stabilization.

Purpose

This prospective randomised controlled trial aims to compare the clinical and radiological outcomes of ceramic on ceramic, cobalt chrome on ultra-high molecular weight polyethylene, and cobalt chrome on highly cross-linked polyethylene bearing surfaces at a minimum of five years.

Purpose

The Birmingham Mid-Head Resection (BMHR) is a bone-conserving, short-stem alternative to hip resurfacing for patients with compromised femoral head anatomy. It is unclear, however, if an uncemented, metaphyseal fixed stem confers a mechanical advantage to that of a traditional hip resurfacing in which the femoral prosthesis is cemented to the prepared femoral head. Thus, we aimed to determine if a metaphyseal fixed, bone preserving femoral component provided superior mechanical strength in resisting neck fracture compared to a conventional hip resurfacing arthroplasty.

Purpose: Recently, there has been concern raised on the occurrence of pseudotumors after metal on metal hip resurfacing. A pseudotumor is defined as a local soft tissue mass associated with localized bony and/or tissue (muscle) destruction. The primary purpose of this study is to determine the incidence of this complication in several high volume Canadian academic centres.

Method: Nine of the 11 Canadian academic centres who perform metal on metal hip resurfacings were surveyed. The number of metal on metal hip resurfacing arthroplasties performed at each centre was first determined, as were the number of those who have presented with a pseudotumour, and subsequently gone on to revision surgery. The basic demographics of the group were recorded, as were the radiographic and implant design variables for those cases presenting with a pseudotumour.

Results: A sample of 3,400 hip resurfacing arthroplasties performed between 2002 and December 2008 were surveyed. Demographics were tabulated for a sub-sample of these patients. 76% were male, the mean length of follow-up was 3.02 years, mean BMI was 28.65, and mean age was 52.10 years. Three of 3,400 cases presented with a pseudotumour, an incidence of .09%.

Conclusion: Although pseudotumors remain a concern after metal on metal hip resurfacing, the incidence at short to mid term follow-up is very low in this multi-centre academic survey. This information is significantly lower than what other groups have recently reported. Continued close monitoring is required in order to determine what clinical factors are at play.

Purpose: We aimed to preliminarily validate a newly developed system, the radiographic union scale for tibial (RUST) fracture healing. We hypothesized that RUST would demonstrate better inter-rater reliability than assessment of the number of cortices bridged and correlate with functional outcomes at least as strongly as surgeon’s assessment of cortical bridging.

Method: Three blinded orthopaedic trauma surgeons independently assigned a RUST score and a number of cortices bridged by callus (zero to four) to each set of AP and lateral radiographs at each follow up period. RUST is scored from four (definitely not healed) to 12 (definitely healed) based on the presence or absence of callus and of a visible fracture line at the total of four cortices visible.

Results: For 549 sets of reviewed radiographs, inter-rater reliability for RUST scores were found to be substantially higher than for assessment of the number of cortices bridged (intra-class correlation coefficient=0.84; 95% CI, 0.80–0.87 versus kappa = 0.73; 95% CI, 0.64 – 0.81, respectively). Both methods of assessing radiographic healing were strongly correlated with weight-bearing status (r and ρ> 0.50), moderately correlated with patient-reported functional recovery and the SF-36 Physical Functioning component scores (r and ρ> 0.30), and minimally correlated with HUI Mark II scores, return to work, and the SF-36 Role Physical component and Physical Component Summary scores (r and ρ> 0.10). Neither assessment was correlated with patient-reported pain scores. All correlations were similar for RUST and the number of cortices bridged.

Conclusion: This study provides preliminary evidence that RUST can be used as a valid and reliable alternative assessment of tibial fracture healing.

Purpose: Given recent evolving guidelines regarding maximum allowable work hours and emphasis on resident quality of life, novel strategies are required for implementing call schedules. The night float system has been used by some institutions as a strategy to decrease the burden of call on resident quality of life in level one trauma centres. The purpose of this study was to determine whether there are differences in quality of life, work-related stressors, and educational experience between orthopaedic surgery residents in the night float and standard call systems at two level one trauma centres.

Method: This was a prospective cohort study at two level one trauma hospitals comprised of a standard call (1 in 4) group and a night float (5pm-7am, Sunday to Friday) group for each hospital, respectively. Residents completed the Short Form 36 (SF-36) general quality-of-life questionnaire, as well as, questionnaires on stress level and educational experience before the rotation (baseline), at two, four and subsequently at six months. An analysis of covariance (ANCOVA) approach was used to compare between-group differences using the baseline scores as covariates. Wilcoxon Signed-Rank tests (non-parametric) were used to determine if the residents’ SF-36 scores were different from the age and sex matched Canadian norms. Predictors of resident quality of life were analyzed using multivariable mixed models.

Results: Seven residents were in the standard call group and nine in the night float group for a total of 16 residents (all males, mean age=35.1 yrs). Controlling for between-group differences at baseline, residents on the night float rotation had significantly lower role physical (RP), bodily pain (BP), social function (SF) subscale scores (p< 0.05).

Conclusion: Our study suggests that the residents in the standard call group had better health related quality of life in comparison with the night float group. No differences existed in subjective educational benefits and stress level between the groups. The study findings may be limited due to the small sample size. However, this sample size is substantial given the size of most orthopaedic residency programs in North America.

Purpose: There is growing support in the medical literature that patient outcomes are adversely affected by physician fatigue in operator-dependent cognitive and technical tasks. The recent increase in total joint arthroplasty case load has resulted in longer operative days and increased surgeon fatigue. The purpose of this study was to determine if time of day predicts perioperative outcomes and complications in total hip and knee arthroplasty surgery.

Method: The records of all primary Total Hip Arthroplasty (THA) and Total Knee Arthroplasty (TKA) surgery performed for primary osteoarthritis, during 2007 at one large university hospital, were retrospectively reviewed. Complete demographic data (age, gender, Body Mass Index), start time of surgery, intraoperative complications, duration of surgery, radiographic component alignment, and functional outcome scores (SF-12 and WOMAC) for 341 THA and 292 TKA patients were collected and analyzed using linear and nonparametric rank correlation statistics. Data was corrected for gender, body mass index (BMI), surgeon, and post-call operating days.

Results: In the THA cohort, a later start time of surgery was significantly related to duration of surgery (p=0.0013). In addition, there was a trend towards significance for intraoperative femur fracture (p=0.0542) later in the day. Postoperative complications, component alignment, and functional outcome scores were not significantly affected by start time of surgery. There were no significant findings for any of the intraoperative or postoperative outcomes in the TKA cohort.

Conclusion: This study demonstrates that duration of surgery and the incidence of intraoperative complications for THA may increase as the start time of surgery becomes later in the day. These findings should be taken into consideration when planning operative days involving THA.

Purpose: Surgeons performing hip resurfacing antevert and translate the femoral component anteriorly to maximize head/neck offset and reduce impingement. The anterior femoral neck is under tensile forces during gait similarly to the superior neck [6]. This study was designed to determine the risk of femoral neck fracture after anterior or posterior notching of the femoral neck.

Method: Forty seven fourth generation synthetic femora were implanted with Birmingham Hip Resurfacing prostheses (Smith & Nephew Inc. Memphis, USA). Implant preparation was performed using imageless computer navigation (VectorVision SR 1.0, BrainLAB, Germany). The prosthesis was initially planned for neutral version and translated anterior, or posterior, to create a femoral neck notch. The femora were fixed in a single-leg stance and tested with axial compression using a mechanical testing machine. This method enabled comparison with previously published data. The synthetic femora were prepared in eight experimental groups:two mm and five mm anterior notches, two mm and five mm posterior notches, neutral alignment with no notching (control), five mm superior notch, five mm anterior notch tested with the femur in 25° flexion and five mm posterior notch tested with the femur in 25° extension We tested the femora flexed at 25° flexion to simulate loading as seen during stair ascent. [3] The posterior five mm notched femoral necks were tested in extension to simulate sporting activities like running. The results were compared to the control group in neutral alignment using a one – way ANOVA:

Results: Testing Group Mean load to failure Significance (p-value) Anterior 2mm 3926.61 ± 894.17 .843 Anterior 5mm 3374.64 ± 345.65 .155 Neutral (Control) 4539.44 ± 786.44 – Posterior 2mm 4208.09 ± 1079.81 .994 Posterior 5mm 3988.06 ± 728.59 .902 Superior 5mm 2423.07 ± 424.17 .001 Anterior 5mm in 25° flexion 3048.11 ± 509.24 .027 Posterior 5mm in 25° extension 3104.62 ± 592.67 .038 Our data suggests that anterior and posterior two mm or five mm notches are not significantly weaker in axial compression. Anterior and posterior 5mm notches are significantly weaker in flexion/extension (p=0.027/ p=0.038). The five mm superior notch group was significantly weaker with axial compression supporting previous published data (p=0.001).

Conclusion: We conclude that anterior or posterior two mm notching of the femoral neck has no clinical implications, however five mm anterior or posterior femoral neck notching significantly weakens the femoral neck. Fracture is more likely to occur with stair ascent or activities involving weight bearing in extension. Hip resurfacing is commonly performed on active patients and five mm neck notching has clinically important implications.

Purpose: In recent years, there has been an increased appreciation of the importance of intimate partner violence (IPV), which is also known as domestic violence, spouse abuse, and battering, as a serious public health problem. Domestic violence is the most common cause of nonfatal injury to women in North America. As providers of musculoskeletal care and first-contact health care practitioners for many patients, orthopaedic surgeons should be knowledgeable regarding screening and possible interventions for IPV victims. The Canadian Orthopaedic Association and the American Academy of Orthopaedic Surgeons have both prepared explicit statements that orthopaedic surgeons should play a role in the screening and appropriate identification of victims of IPV. We aimed to identify the knowledge, attitudes, and beliefs about IPV among orthopaedic surgeons who are members of the Orthopaedic Trauma Association.

Method: We surveyed members of the Orthopaedic Trauma Association to identify attitudes toward IPV by posting a survey on the Orthopaedic Trauma Association website for its membership to complete. The survey consisted of three sections:

the general attitude of the orthopaedic surgeon toward intimate partner violence,

Results: One-hundred-and-fifty-three orthopaedic surgeons responded. The majority of the respondents were male (99%) with practices in North America (96%). Surgeons underestimated the prevalence of IPV in their practices and communities and manifested several key misconceptions:

victims must be getting something out of the abusive relationships (16%);

In the past year, approximately half of the surgeons (50.8%) acknowledged identification of a victim of IPV; however, only 4.0% of respondents currently screened for IPV among female patients with injuries. Surgeons expressed concerns about lack of knowledge in the management of abused women (30%) Guidelines for the detection and management of IPV were uncommon in most surgeons’ practices (7.8%).

Conclusion: There is a strong rationale for addressing IPV as an issue that is relevant to the field of orthopaedic surgery just as it has been shown to be relevant to primary care, emergency medicine, and obstetrics and gynecology. Our study found that orthopaedic surgeons underestimated the prevalence of IPV in their practices, held multiple misperceptions about IPV, and demonstrated discomfort in identifying and treating IPV. Targeted educational programs on IPV are needed for surgeons who routinely care for injured women.

Purpose: Intimate partner violence (IPV), also known as domestic violence, is a pattern of coercive behaviors that include repeated physical, sexual and emotional abuse. Musculoskeletal injuries are common manifestations of IPV. We aimed to determine the proportion of women presenting to orthopaedic fracture clinics for treatment of orthopaedic injuries that have experienced IPV defined as physical, sexual, or emotional abuse within the past 12 months.

Method: We completed a cross-sectional study of 282 injured women attending two Level I trauma centres in Canada. Female patients presenting to the orthopaedic fracture clinics completed two validated self-reported written questionnaires (Woman Abuse Screening Tool (WAST) and the Partner Violence Screen (PVS)) to determine the prevalence of IPV. The questionnaire also contained questions that pertain to the participant’s demographic, fracture characteristics, and experiences with health care utilization.

Results: The overall prevalence of IPV (emotional, physical, and sexual abuse) within the last 12 months was 32% (95% Confidence Interval 26.4% to 37.2%) (89 of 282 women). One in 12 injured women disclosed a history of physical abuse (24/282, 8.5%) in the past year. Seven women (2.5%) indicated the cause for their current visit was directly related to physical abuse, of which five were fractures. We did not identify any significant trends in ethnicity, socioeconomic status, or injury patterns as markers of domestic abuse. Of 24 women with physical injuries, only four had been asked about IPV by a physician, none of whom were their treating orthopaedic surgeons.

Conclusion: Our study confirms a high prevalence of IPV among female patients with injuries attending orthopaedic surgical clinics in Ontario. Similar to previous research our study found that women of all ages, ethnicities, social economic status, and injury patterns may experience IPV. Surgeons should consider screening all injured women for domestic violence in their clinics.

Purpose: The purpose of this study was to evaluate the accuracy and precision of 3 common methods used to produce posterior tibial slope during total knee arthroplasty.

Method: The study population consisted of 110 total knee arthroplasties in 102 patients that underwent total knee arthroplasty. All procedures were performed using a standard medial parapatellar approach and all knees were replaced using the Scorpio Knee System (Stryker, Mahwah, NJ) of implants and instruments. Three treatment groups were identified retrospectively based on the method used to produce the posterior tibial slope. Group 1 used an extramedullary guide with a 0 degree cutting block tilted by placing 2 fingers between the tibia and the extramedullary guide proximally and three fingers between the tibia and guide distally to produce a 3 degree posterior slope (N=40). Group 2 used computer navigation (Stryker Navigation System, Stryker, Mahwah, NJ) to produce a 3 degree posterior slope (N=30). Group 3 used an extramedullary guide placed parallel to the anatomic axis of the tibia with a 5 degree cutting block to produce a 5 degree posterior slope (N=40). Posterior tibial slope was measured from lateral radiographs by 2 independent reviewers that were blinded to the treatment group. The reported posterior tibial slope for each sample was an average of these two measurements. Accuracy of the treatment group was evaluated using a one sample t test. Groups 1 and 2 were tested for an ideal slope of 3 degrees, and Group 3 was tested for an ideal slope of 5 degrees. An a priori sample size calculation with α=0.05 and β=0.20 showed that at least 24 samples in each treatment group were required to determine a difference of 1.5 degrees between the treatment group mean posterior tibial slope and the ideal posterior tibial slope.

Results: The mean posterior slope measurements for treatment Group 1 (4.15±3.24 degrees) and treatment Group 2 (1.60±1.62 degrees) were both significantly different than the ideal slope of 3 degrees (p=0.03 for Group 1 and p< 0.01 for Group 2). This indicates that treatment Groups 1 and 2 failed to accurately produce the ideal posterior tibial slope of 3 degrees. The mean posterior tibia slope of treatment Group 3 (5.00±2.87 degrees) was not significantly different than the ideal posterior tibial slope of 5 degrees (p=1.00). This indicates that Group 3 accurately produced the ideal tibial slope of 5 degrees.

Conclusion: The most accurate method to produce posterior tibial slope was the 5 degree cutting block with an extramedullary guide. Computer navigation had the lowest standard deviation and therefore was the most precise method. However, computer navigation was not as accurate in producing the desired posterior tibial slope as the extramedullary guide with the 5 degree cutting block. The manual method of producing tibial slope with an extramedullary guide and a 0 degree cutting block was the least precise method and not as accurate as the extramedullary guide with a 5 degree cutting block.

Purpose: Optimal fixation for comminuted proximal humerus fractures is controversial. Complications using locked plates have been addressed by anatomic reduction or medial cortical support. The current study measured relative mechanical contributions of varus malalignment and medial cortical support.

Method: Forty synthetic humeri were divided into three groups, osteotomized, and fixed at 0, 10, and 20 degrees of varus malreduction with locked proximal humerus plates (AxSOS, Global model, Stryker, Mahwah, NJ, USA). This simulated mechanical medial support with the cortex intact. Axial, torsional, and shear stiffness were experimentally measured. Half of the specimens in each of the groups underwent a second osteotomy to create a segmental defect which simulated loss of medial support with the cortex removed. Axial, torsional, and shear stiffness experiments were repeated, followed by shear load to failure in 20 degrees of abduction.

Results: For isolated malreduction with the cortex intact, the repair construct at 0 degrees showed statistically equivalent or higher axial, torsional, and shear stiffness than other groups assessed. Subsequent removal of cortical support in half the specimens resulted in a drastic effect on axial, torsional, and shear stiffness at all varus angles. Repair constructs with the cortex intact at 0 and 10 degrees resulted in mean shear failure forces of 12965.4 N and 9341.1 N, respectively. These were statistically higher (p< 0.05) compared to most other groups tested. Specimens failed mainly by plate bending as the femoral head was pushed down medially and distally.

Conclusion: Anatomic reduction with the medial cortex intact was the stiffest construct after a simulated two-part fracture. This study also supports the practice of achieving medial cortical support by fixing proximal humeral fractures in varus if necessary. This may be preferable to fixing the fracture in anatomic alignment when there is a medial fracture gap.

Purpose: The purpose of this study was to compare the effects of two types of stem/progenitor cells on the healing of critical sized bone defects in a rat model. Endothelial Progenitor Cells (EPCs), a novel cell type with previously demonstrated effects on angiogenesis in animal models of vascular disease, were compared to both a control group of no cell therapy, and a treatment group of Mesenchymal Stem Cells (MSCs). The hypothesis was that EPCs would demonstrate both superior bone healing and angiogenesis, when compared to the control group and MSC group.

Method: EPCs and MSCs were isolated from the bone marrow of syngeneic rats by differential culture and grown ex vivo for 10 days. Subsequently the cells were harvested, seeded on a gelfoam scaffold, and implanted into a 5mm segmental defect in a rat femur that had been stabilized with a plate and screws. Bone healing was assessed radiographically and by microCT. Angiogenesis was assessed by histology and physiologically, using laser doppler to assess blood flow in the bone and soft tissues. All animal protocols were approved by and performed in accordance with the St. Michael’s Hospital Animal Care Committee. ANOVA was used to test for significant differences between the groups, and a p-value of < 0.05 was considered statistically significant.

Results: The EPC (n=14) group demonstrated radiographic evidence of healing of the bone defect as early as 2 weeks, and all specimens were radiographically healed at 6 weeks. Both the control group (n=14) and the MSC group (n=14) showed no radiographic evidence of healing at 10 weeks. MicroCT comparison of the EPC group versus the control group showed significantly greater bone volume and density at the defect site (p< 0.001). More blood vessel formation was observed in the EPC group versus the control group on histology at 2 weeks. Laser Doppler assessment showed significantly more soft tissue and bone blood flow at 2 and 3 weeks in the EPC group versus the control group (p=0.021).

Conclusion: The results of this study demonstrate that EPCs are effective as cell-based therapy for healing critical sized bone defects in a rat model. In this model EPCs demonstrated superiority to MSCs with regard to bone healing. In addition, EPCs demonstrated superior angiogenesis over controls in a rat model of fracture healing. These results strongly suggest that EPCs are effective for therapeutic angiogenesis and osteogenesis in fracture healing. There is a clinical need for effective strategies in the management of traumatic bone defects and nonunions. Investigation into the use of MSCs as an effective alternative to autologous bone grafting has failed to translate into clinical use. It is possible that EPCs are more effective at the regeneration of bone in segmental defects because of their synergistic effect on angiogenesis and osteogenesis. Further research into EPC based therapies for fracture healing is warranted.