Determine the prevalence, etiologies, and risk factors of unplanned return to the OR (UROR) in adult orthopaedic trauma patients. Retrospective review of a trauma prospective registry from 2014 – 2019 at a Level 1 academic hospital. An UROR was defined as a patient returning to OR unexpectedly following a planned definitive surgery to either readdress the presenting diagnosis or address a complication arising from the index procedure. Univariate and multivariate logistic regression was performed comparing those patients with an UROR versus those without. A total of 1568 patients were reviewed. The rate of UROR was 9.8% (153 patients). Symptomatic implant was the leading cause of UROR (60%). Other significant UROR causes were infection (15%) and implant failure (9%). The median time between index procedure and UROR was 301 days. For the univariate and multivariate analysis, open fracture (p< 0.05), fracture complexity (p<0.01), and weekend procedure (p< 0.01) were all associated with increased risk of UROR. All other variables were not statistically significant for any associations. Those patients with an UROR for reasons other than symptomatic implants were more likely to have polyorthopaedic injuries (p < 0.05), ISS > 15 (p < 0.05), osteoporosis (p < 0.01), ICU status (p < 0.05), psychiatric history (p < 0.05), compartment syndrome (p < 0.05), neurovascular injury (p < 0.01), open fracture (p < 0.05), and fracture complexity (p < 0.05). The rate of UROR in the orthopaedic trauma patient population is 10%. Most of these cases are due to implant-related issues. UROR for reasons other than symptomatic implants tend to be polytraumatized patients with higher-energy injuries, multiple complex fractures, and associated soft tissue injuries. Future focus on improved implant development and treatments for polytraumatized patients with complex fractures is warranted to decrease a relatively high UROR rate in orthopaedic trauma.
Bone metastasis ultimately occurs due to a complex multistep process, during which the interactions between cancer cells and bone microenvironment play important roles. Prior to colonization of the bone, cancer cells must succeed through a series of steps that will allow them to gain migratory and invasive properties; epithelial-to-mesenchymal transition (EMT) is known to be integral here. The aim of this study was to determine the effects of G protein subunit alpha Q (GNAQ) on the mechanisms underlying bone metastasis through EMT pathway. A total of 80 tissue samples from patients who were surgically treated during January 2012 to December 2014 were used in the present study. Comparative gene analysis revealed that the GNAQ was more frequently altered in metastatic bone lesions than in primary tumour sites in lung cancer patients. We investigated the effects of GNAQ on cell proliferation, migration, EMT, and stem cell transformation using lung cancer cells with GNAQ-knockdown. A xenograft mouse model tested the effect of GNAQ using micro-CT analyses and histological analyses.Aims
Methods
Receptor activator of nuclear factor-κB ligand (RANKL) is a key molecule that is expressed in bone stromal cells and is associated with metastasis and poor prognosis in many cancers. However, cancer cells that directly express RANKL have yet to be unveiled. The current study sought to evaluate how a single subunit of G protein, guanine nucleotide-binding protein G(q) subunit alpha (GNAQ), transforms cancer cells into RANKL-expressing cancer cells. We investigated the specific role of GNAQ using Aims
Methods
Management and outcomes of fungal periprosthetic joint infection (PJI) remain unclear due to its rarity. Although two-stage exchange arthroplasty is considered a treatment of choice for its chronic features, there is no consensus for local use of antifungal agent at the 1st stage surgery. The purpose of this study was to evaluate the efficacy of antifungal-impregnated cement spacer in two-stage exchange arthroplasty against chronic fungal PJIs after total knee arthroplasty (TKA). Nine patients who were diagnosed and treated for chronic fungal PJIs after TKA in a single center from January 2001 to December 2016 were enrolled. Two-stage exchange arthroplasty was performed. During the 1st stage resection arthroplasty, amphotericin-impregnated cement spacer was inserted for all patients. Systemic antifungal medication was used during the interval between two stage operations. Patients were followed up for more than 2 years after exchange arthroplasty and their medical records were reviewed.Purpose
Methods
The aim of this study was to evaluate improvements in the quality
and safety of paediatric spinal surgery following the implementation
of a specialist Paediatric Spinal Surgical Team (PSST) in the operating
theatre. A retrospective consecutive case study of paediatric spinal operations
before (between January 2008 and December 2009), and after (between
January 2012 and December 2013) the implementation of PSST, was
performed. A comparative analysis of outcome variables including
surgical site infection (SSI), operating time (ORT), blood loss (BL),
length of stay (LOS), unplanned staged procedures (USP) and transfusion
rates (allogenic and cell-saver) was performed between the two groups.
The rate of complications during the first two postoperative years
was also compared between the groups.Aims
Patients and Methods
Most patients presenting with loss of hip motion secondary to FAI have a combination of cam and pincer morphology. In this study, we present a composite index for predicting joint ROM based on anatomic parameters derived from both the femur and acetabulaum using a single reformatted CT slice. Computer models of the hip joint were reconstructed from CT scans of 31 patients with mixed-type FAI (Average alpha angle: 73.6±11.1°, average LCE: 38.9±7.2°). The internal rotation of the hip at impingement was measured at 90° flexion using custom software. With the joint in neutral, a single slice perpendicular to the acetabular rim was taken at the 2 o'clock position. A set of 11 femoral and acetabular parameters measured from this slice were correlated with hip ROM using stepwise logistic regression. Three anatomic parameters provided significant discrimination of cases impinging at <15 and >15 degrees IR: femoral anteversion (28%, p=0.026), the arc of anterior femoral head sphericity (10%, p=0.040), and the LCE in the 2 o'clock plane (10%, p=0.048). This led to the following definition of the Impingement Index: 0.16*(fem version) +0.11*(ant arc)−0.17*(LCE) which correctly classified 82% of cases investigated. None of the traditional parameters (e.g. alpha angle) were significantly correlated with ROM. Our study has identified alternative morphologic parameters that could act as strong predictors of FAI in preoperative assessments. Using this information, each patient's individual risk of impingement may be estimated, regardless of the relative contributions of deformities of the femur and the acetabulum.
Numerous factors have been hypothesized as contributing to mechanically-assisted corrosion at the head-neck junction of total hip prostheses. While variables attributable to the implant and the patient are amenable to investigation, parameters describing assembly of the component parts can be difficult to determine. Nonetheless, increasing evidence suggests that the manner of intraoperative assembly of modular components plays a critical role in the fretting and corrosion of modular implants. This study was undertaken to measure the magnitude and direction of the impaction forces applied by surgeons in assembling modular head-neck junctions under operative conditions where both the access and visibility of the prosthesis may potentially compromise component fixation. A surrogate consisting of the lower limb with overlying soft tissue was developed to simulate THR performed via a 10cm incision using the posterior approach. The surrogate was modified to match the resistance of the body to retraction of the incision, mobilization of the femur and hammering of the implanted femoral component. An instrumented femoral stem (SL PLUS) was surgically implanted into the bone after attachment of 3 miniature accelerometers (Dytran Inc) in an orthogonal array to the proximal surface of the prosthesis. A 32mm cobalt chrome femoral head was mounted on the trunnion (12/14 taper, machined) of the femoral stem. 15 Board-certified and trainee surgeons replicated their surgical technique in exposing the femur and impacting the modular head on the tapered trunnion. Impaction was performed using an instrumented hammer (5000 Lbf Dytran impact hammer) that provided measurements of the magnitude and temporal variation of the impact force. The components of force acting along the axis aof the neck and in the AP and ML directions were continuously samples using the accelerometers.Introduction
Methods
Lateralizing the center of rotation (COR) of reverse total shoulder arthroplasty (rTSA) has the potential to increase functional outcomes of the procedure, namely adduction range of motion (ROM). However, increased torque at the bone-implant interface as a result of lateralization may provoke early implant loosening, especially in situations where two, rather than four, fixation screws are used. The aim of this study was to utilize finite element (FE) models to investigate the effects of lateralization and the number of fixation screws on micromotion and adduction ROM. Four patient-specific scapular geometries were developed from CT data in 3D Slicer using a semi-automatic threshold technique. A generic glenoid component including the baseplate, a lateralization spacer, and four fixation screws was modelled as a monoblock. Screws were simplified as 4.5 mm diameter cylinders. The glenoid of each scapula was virtually reamed after which the glenoid component was placed. Models were meshed with quadratic tetrahedral elements with an edge length of 1.3 mm. The baseplate and lateralization spacer were assigned titanium material properties (E = 113.8 GPa and ν = 0.34). Screws were also assigned titanium material properties with a corrected elastic modulus (56.7 GPa) to account for omitted thread geometry. Cortical bone was assigned an elastic modulus of 17.5 GPa and Poisson's ratio of 0.3. Cancellous bone material properties in the region of the glenoid were assigned on an element-by-element basis using previously established equations to convert Hounsfield Units from the CT data to density and subsequently to elastic modulus [1]. Fixed displacement boundary conditions were applied to the medial border of each scapula. Contact was simulated as frictional (μ = 0.8) between bone and screws and frictionless between bone and baseplate/spacer. Compressive and superiorly-oriented shear loads of 686 N were applied to the baseplate/spacer. Lateralization of the COR up to 16 mm was simulated by applying the shear load further from the glenoid surface in 4 mm increments (Fig. 1A). All lateralization levels were simulated with four and two (superior and inferior) fixation screws. Absolute micromotion of the baseplate/spacer with respect to the glenoid surface was averaged across the back surface of the spacer and normalized to the baseline configuration considered to be 0 mm lateralization and four fixation screws. Adduction ROM was measured as the angle between the glenoid surface and the humeral stem when impingement of the humeral cup occurred (Fig. 1B).Introduction
Methods
Ultra-high molecular weight polyethylene (UHMWPE) has been used for the bearing liner or inlay components in total joint replacements such as total hip, knee, and artificial disk since 1960’s. UHMWPE components generate wear debris during articulation, which play a key role in osteolysis, subsequent aseptic loosening, and eventually revision surgery. Efforts to solve the wear problem in UHMWPE and to quantify the amount of wear have driven many studies. But in vivo radiographic penetration depth measurement is the result of both wear and viscoelastic creep. Previous study reported that over 70% of the dimensional changes in UHMWPE acetabular cups were due to creep. Creep deformation was quantified under the static and dynamic compressive pressures (2, 4, 8Mpa) that are clinically relevant for the hip joint loads in normal motions. However, according to the finite element stress analyses in UHMWPE components under the active motions in hip, knee, and artificial disk replacements, very high level of contact pressures locally ranged from under 10MPa up to over 60Mpa. In this study, we quantified the creep of UHMWPE under the several high levels of dynamic compressive pressures and compared the results from the previous results. For creep tests, UHMWPE rectangular blocks (10mm long, 10mm wide, 8mm thick) were manufactured from molded unirradiated Chirulen® 1020 sheet (MediTECH, Deutchland). MTS 858 hydraulic test machine was used for conducting the dynamic compressive creep tests under the four different sinusoidal (1Hz) maximum pressures of 10, 20, 40, and 60MPa and minimum pressures of 1, 2, 4, and 6MPa, respectively. All tests were conducted for a total duration of 4×103 minutes at ambient conditions. During the test the displacements of crosshead were stored and the changes in thickness of block specimen devided by the initial thickness were calculated to get the creep strain. The mean dynamic compressive creep strain increased as the loading time increased and had a linear relationship (R2=0.96) with the logarithmic scale of time for all maximun pressures. Over 90% of total creep strain occurred within the first 103 minutes. The rates of creep strain (slopes of curve fitting in logarithmic scale of time) for each maximum pressure were listed in Table 1 with the rates of creep strain for low maximum pressures from the previous study [3]. The rates of creep strain increased linearly as the maximum pressure increased for both current study (R2=0.96) and previous study (R2=0.99). The slope of linearity for the current study with high levels of contact pressures was a little larger than that for the previous study with low levels of contact pressures. This difference in the slope of linearity between current and previous studies lies in the creep recovery during measurement of specimen thickness by micrometer in the previous study. Neglecting this difference, the results of current study can be extrapolated to anticipate the creep strain of UHMWPE under the dynamic compression for the low levels of contact pressures.
To assess patient following operative fixation of clavicle fractures. In the literature, the incidence of paraesthesia following operative fixation of clavicle fractures is reported to be between 7–29%. This problem can be bothersome to patients and the degree of disability is poorly documented. All clavicle fractures (67) treated operatively at the Alfred Hospital between 01/06/2003 and 01/06/2006 were included in the study. Patients were asked to complete paper based questionnaires assessing satisfaction, presence of numbness and degree of disability following clavicle operation. Additionally, they were followed up clinically to assess the area of numbness and scarring. The response rate was 65% (43/67). Most of the patients were satisfied with the operation and only 15% reported significant problems with the wound. Majority of patients returned to pre-morbid activities and employment. The degree of paraesthesia varied among respondents and it was associated with the type of incision used. There was little difference in patient satisfaction with regard to various surgical devices utilised. It is important to address wound complications such as scarring and paraesthesia when discussing operative treatments for patients with clavicle fractures. The results suggest that wound related problems can be frequent and a significant percentage of operatively managed patient experience long term numbness. It is possibly an under appreciated problem. Additionally our results suggest that vertical incisions achieve a more favourable outcome compared to horizontal incisions.
To report the results of the intramedullary skeletal kinetic distractor (iskd) in patients with established leg length discrepancy following lower limb trauma. 12 patients with significant leg length discrepancy (>
20mm) following lower limb trauma were operated on using the iskd nail between september 2004 and december 2007. patients were followed up clinically and radiologically at minimum 18 months (mean: 27months range: 18–24 months). 8 femurs and 4 tibias were operated using the iskd nail. all patient in the series had successful completed treatements. the average leg length discrepancy was 38mm (91mm–21mm) and the average gained length was 37mm (76m–22mm). radiological union and bone consolidation were slow to occur. early weight bearing was permitted allowing earlier functional capacity. 6 patients required additional operations; 3 manipulation under anaesthesia for failed lengthening and 3 bone grafting for poor regenerate, 1 patient required more than one additional operation. The iskd nail is an effective and reliable alternative technique for correcting leg length discrepancy in patients who have suffred lower limb trauma. it appears to mimic the results achieved with the use of a fine wire external fixator or a unilateral external fixator. the convenience of a fully implanted device is substantial. the complications are frequent but manageable with standard techniques.
Ten patients, who were unsuitable for limb lengthening over an intramedullary nail, underwent lengthening with a submuscular locking plate. Their mean age at operation was 18.5 years (11 to 40). After fixing a locking plate submuscularly on the proximal segment, an external fixator was applied to lengthen the bone after corticotomy. Lengthening was at 1 mm/day and on reaching the target length, three or four screws were placed in the plate in the distal segment and the external fixator was removed. All patients achieved the pre-operative target length at a mean of 4.0 cm (3.2 to 5.5). The mean duration of external fixation was 61.6 days (45 to 113) and the mean external fixation index was 15.1 days/cm (13.2 to 20.5), which was less than one-third of the mean healing index (48 days/cm (41.3 to 55). There were only minor complications. Lengthening with a submuscular locking plate can successfully permit early removal of the fixator with fewer complications and is a useful alternative in children or when nailing is difficult.
