Classification systems for tibial plateau fractures suffer from poor interobserver agreement, and their value in preoperative assessment to guide surgical fixation strategies is limited. For tibial plateau fractures four major characteristics are identified: lateral split fragment, posteromedial fragment, anterior tubercle fragment, and central zone of comminution. These fracture characteristics support preoperative assessment of fractures and guide surgical decision-making as each specific component requires a respective fixation strategy. We aimed to evaluate the additional value of 3D-printed models for the identification of tibial plateau fracture characteristics in terms of the interobserver agreement on different fracture characteristics. Preoperative images of 40 patients were randomly selected. Nine trauma surgeons, eight senior and eight junior registrars indicated the presence or absence of four fracture characteristics with and without 3D-printed models. The Fleiss kappa was used to determine interobserver agreement for fracture classification and for interpretation, the Landis and Koch criteria were used. 3D-printed models lead to a categorical improvement in interobserver agreement for three of four fracture characteristics: lateral split (Kconv = 0.445 versus K3Dprint = 0.620; P < 0.001), anterior tubercle fragment (Kconv = 0.288 versus K3Dprint = 0.449; P < 0.001) and zone of comminution (Kconv = 0.535 versus K3Dprint = 0.652; P < 0.001). The overall interobserver agreement improved for three of four fracture characteristics after the addition of 3D printed models. For two fracture characteristics, lateral split and zone of comminution, a substantial interobserver agreement was achieved. Fracture characteristics seem to be a more reliable way to assess tibial plateau fractures and one should consider including these in the preoperative assessment of tibial plateau fractures compared to the commonly used classification systems.
Alignment of the initial femoral guidewire is critical in avoiding technical errors that may increase the risk of failure of the femoral component. A novel alternative to conventional instrumentation for femoral guidewire insertion is a computed tomography (CT) based alignment guide. The aim of this study was to assess the accuracy of femoral component alignment using a CT-based, patient specific femoral alignment guide. Between March 2010 and January 2011, 25 hip resurfacings utilizing a CT-based femoral alignment guide were performed by three surgeons experienced in hip resurfacing. Stem-shaft angle (SSA) accuracy was assessed using minimum 6 week post-operative digital radiographs. A benchside study was also conducted utilizing six pairs of cadaveric femora. Each pair was divided randomly between a group utilizing firstly a conventional lateral pin jig followed by computer navigation and a group utilizing a CT-based custom jig. Guidewire placement accuracy for each alignment method was assessed using AP and lateral radiographs.Introduction:
Methods:
Computer navigation for hip resurfacing has been shown to reduce the incidence of technical error during femoral head preparation and provides increased accuracy compared to conventional instrumentation for insertion of the initial femoral guidewire. Limitations to the widespread use of navigation in hip resurfacing include access and cost. A novel, patient specific nylon jig has been developed as a cost effective alternative for placement of the initial guidewire. The purpose of this study was to compare the accuracy of femoral guidewire insertion between imageless navigation, conventional instrumentation and a new type of CT-based custom jig. Six pairs of cadaveric femora were used in the study. Each pair was divided randomly between a group utilizing firstly a conventional lateral pin jig (BHR, Smith & Nephew Inc.) followed by navigation (Vector Vision SR, BrainLAB) and a group utilizing a CT-based, patient specific custom jig (Visionaire, Smith & Nephew Inc.). A single surgeon inserted all guidewires. The planned guidewire position was approximately 10 degrees of relative valgus to the native neck-shaft angle in the coronal plane and neutral version in the sagittal plane. The same coronal alignment angle was used between paired femora. Femurs were positioned in a draped synthetic foam hip model prepared with a standard posterior approach. Guidewire insertion time and placement accuracy for each of the three alignment methods was assessed. Guidewire placement accuracy for coronal inclination and version was assessed by anteroposterior and lateral digital radiographs and was defined as the mean deviation from the planned alignment value.Purpose
Method
To review prospectively collected data on patients undergoing primary total hip arthroplasty utilizing two different cementless acetabular components. All patients undergoing primary total hip replacement surgery at our institution are entered prospectively into a database which includes history and physical examination, radiology, WOMAC and SF-36 scores. The patients are re-examined, re-x-rayed and re-scored at 3 months, 6 months and 1 year after surgery and yearly thereafter. Using this database we are able to identify patients who have undergone total hip replacement using one of two geometric variants of the acetabular component. The first design is hemispherical and the second design has a peripheral rim expansion designed to increase initial press-fit stability.Purpose
Method
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. The location of the PF and T were digitized under direct visualization with a three-dimensional scribe on ten, fresh-frozen cadaveric right femora (two male, eight female) by three fellowship trained orthopaedic surgeons. To estimate inter- and intraobserver reliability of the direct measurements, an intraclass correlation coefficient was calculated with a minimum of two weeks between measurements. Under navigation, each specimen was draped and antero-posterior (AP) and lateral radiographs of the proximal femur were taken with a c-arm and image intensifier. The c-arm was positioned in a neutral position (0 for AP, 90 for lateral) and rotated in 5 increments, yielding a range of acceptable images. Images, in increments of 5, within the AP range (with a neutral lateral) were loaded into a navigation system (Stryker, MI). A single surgeon digitized the T and PF directly based on conventional fluoroscopy, and again directed by navigation, yielding two measurements per entry point per specimen. This was repeated for the lateral range. Hierarchical linear modelling and a Wilcox rank test were used to determine differences in accuracy and precision, respectively, in the identification of PF and T using computer navigation vs. conventional fluoroscopy.Purpose
Method
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. One hundred and two primary total hip replacements were performed in ninety one patients between February 2003 and March 2005. All patients were younger than 65 (mean 52.7, 19–64). They were randomised to receive one of the three bearing surfaces. All patients had 28mm articulations with a Reflection uncemented acetabular component and a Synergy stem (Smith & Nephew, Memphis, Tennessee). Patients were followed up periodically up to at least sixty months following surgery. Outcome measures included WOMAC and SF12 scores. Radiological assessment included implant position, evidence of osteolysis and measurement of linear wear.Purpose
Method
To review prospectively collected data on patients undergoing primary total hip arthroplasty utilizing two different cementless acetabular components. All patients undergoing primary total hip replacement surgery at our institution are entered prospectively into a database which includes history and physical examination, radiology, WOMAC and SF-36 scores. The patients are re-examined, re-x-rayed and re-scored at 3 months, 6 months and 1 year after surgery and yearly thereafter. Using this database we are able to identify patients who have undergone total hip replacement using one of two geometric variants of the acetabular component. The first design is hemispherical and the second design has a peripheral rim expansion designed to increase initial press-fit stability. Five hundred and twenty-seven consecutive primary total hip replacements were identified using either of the geometric variants of the acetabular component. Results at a mean of 7 years revealed a 95.6% survivorship with no significant difference between the two component designs with revision for aseptic loosening as the end point. Functional scores between the two groups of patients also demonstrated no statistically significant difference. Radiologic assessment, however, showed a difference between the two designs. The hemispherical design which matches the reamer line-to-line had 80% complete osseointegration on final radiologic review while the second design with a peripheral rim expansion had only 57% complete osseointegration. This was statistically significant. The peripherally expanded components also had a greater number of screws inserted at the time of surgery, felt by us to be a reflection of initial surgeon dissatisfaction with component stability at the time of insertion of the component. The difference in screw numbers was also statistically significant. This study demonstrates that a hemispherical design with line-to-line contact between the acetabular component surface and the acetabular bone is statistically superior in terms of bone ingrowth and probably statistically superior in terms of initial press-fit stability when compared to a peripherally expanded component. Peripherally expanded components appear to offer no advantage over hemispherical components in terms of clinical outcome and are statistically inferior to hemispherical components in radiologic parameters at 7 years follow-up.
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. One hundred and two primary total hip replacements were performed in ninety one patients between February 2003 and March 2005. All patients were younger than 65 (mean 52.7, 19–64). They were randomised to receive one of the three bearing surfaces. All patients had 28mm articulations with a Reflection uncemented acetabular component and a Synergy stem (Smith & Nephew, Memphis, Tennessee). Patients were followed up periodically up to at least sixty months following surgery. Outcome measures included WOMAC and SF12 scores. Radiological assessment included implant position, evidence of osteolysis and measurement of linear wear. Ninety seven hip replacements in eighty seven patients were available for review at a minimum of five years. Two hips were revised (one for infection and one for periprosthetic fracture), leaving a total of ninety four hips available for final review. There were no differences in age, gender, body mass index, diagnosis, level of activity, and co-morbidities between the three groups. At a minimum of five years there were no statistical differences in the clinical outcomes using the WOMAC or SF12 scores. Three patients in the ceramic group reported squeaking. Radiological evaluation revealed mean annual wear rates in the ceramic group of 0.006mm/yr, standard polyethylene of 0.151mm/yr and highly cross linked polyethylene of 0.059mm/yr. ANOVA analysis revealed these differences in wear rates to be significant (p<0.0001). In the mid term there are no differences in clinical outcome between ceramic on ceramic, cobalt chrome on ultra-high molecular weight polyethylene, and cobalt chrome on highly cross-linked polyethylene bearing surfaces in total hip arthroplasty. Ultra high molecular weight polyethylene has a significantly greater annual linear wear rate than highly cross-linked polyethylene.
To review prospectively collected data on patients undergoing primary total hip arthroplasty utilizing two different cementless acetabular components. All patients undergoing primary total hip replacement surgery at our institution are entered prospectively into a database which includes history and physical examination, radiology, WOMAC and SF-36 scores. The patients are re-examined, re-x-rayed and re-scored at 3 months, 6 months and 1 year after surgery and yearly thereafter. Using this database we are able to identify patients who have undergone total hip replacement using one of two geometric variants of the acetabular component. The first design is hemispherical and the second design has a peripheral rim expansion designed to increase initial press-fit stability.Purpose
Materials & Methods
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. One hundred and two primary total hip replacements were performed in ninety one patients between February 2003 and March 2005. All patients were younger than 65 (mean 52.7, 19-64). They were randomised to receive one of the three bearing surfaces. All patients had 28mm articulations with a Reflection uncemented acetabular component and a Synergy stem (Smith & Nephew, Memphis, Tennessee). Patients were followed up periodically up to at least sixty months following surgery. Outcome measures included WOMAC and SF12 scores. Radiological assessment included implant position, evidence of osteolysis and measurement of linear wear.Aim
Methods
Parallel operating lists are a contentious subject. Many people feel that supervision, training and quality of patient care is negatively affected and consider this an outdated model in modern practice. Dual and parallel lists have been largely abandoned due to training committees' opinions that standards of orthopaedic training were being negatively affected. A new model of dual lists was implemented in a district general hospital as part of an arthroplasty service. The training impact was evaluated. Adjacent theatres were utilised for a single session. Two joint replacement surgeries were undertaken in each theatre. The sequential timing of the lists allowed the consultant to perform or supervise all of the operations in a consecutive manor. Staggering the start times allowed the consultant to approach and implant the first joint replacement, leaving the junior doctor or nurse practitioner to close the first operation and get the patient off the table while the consultant transferred to the adjoining theatre where the registrar had positioned, painted and draped the second patient, allowing the consultant to perform or supervise the second surgery. The process was then repeated until all four cases were performed. Evaluation of two registrar's elogbooks was undertaken and compared to the national average. During a twelve month period the trainees was involved in a mean of 72 joint replacement surgeries compared to a national average of 49. The trainees were the primary surgeon in a significantly higher number of operations compared to the national average. This model of sequential operating lists facilitated a service of high volume arthroplasty surgeries and significantly increased the exposure of the training registrar to joint replacements. Supervision of trainees was not significantly impacted. The model requires effective support services and a dedicated team of theatre staff, but can be very rewarding for consultant surgeon and trainee alike.
