Aims

Machine-learning (ML) prediction models in orthopaedic trauma hold great promise in assisting clinicians in various tasks, such as personalized risk stratification. However, an overview of current applications and critical appraisal to peer-reviewed guidelines is lacking. The objectives of this study are to 1) provide an overview of current ML prediction models in orthopaedic trauma; 2) evaluate the completeness of reporting following the Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis (TRIPOD) statement; and 3) assess the risk of bias following the Prediction model Risk Of Bias Assessment Tool (PROBAST) tool.

Aim

There is growing evidence that bacteria encountered in periprosthetic joint infections (PJI) form surface-attached biofilms on prostheses, as well as biofilm aggregates embedded in synovial fluid and tissues. However, models allowing the investigation of these biofilms and the assessment of their antimicrobial susceptibility in physiologically relevant conditions are currently lacking. To address this, we developed a synthetic synovial fluid (SSF) model and we validated this model in terms of growth, aggregate formation and antimicrobial susceptibility testing, using multiple PJI isolates.

The computational modelling and 3D technology are finding more and more applications in the medical field. Orthopedic surgery is one of the specialties that can benefit the most from this solution. Three case reports drawn from the experience of the authors’ Orthopedic Clinic are illustraded to highlight the benefits of applying this technology.

Drawing on the extensive experience gained within the authors’ Operating Unit, three cases regarding different body segments have been selected to prove the importance of 3D technology in preoperative planning and during the surgery. A sternal transplant by allograft from a cryopreserved cadaver, the realization of a custom made implant of the glenoid component in a two-stage revision of a reverse shoulder arthroplasty, and a case of revision on a hip prosthesis with acetabular bone loss (Paprosky 3B) treated with custom system. In all cases the surgery was planned using 3D processing software and models of the affected bone segments, printed by 3D printer, and based on CT scans of the patients. The surgical implant was managed with dedicated instruments.

The use of 3D technology can improve the results of orthopedic surgery in many ways: by optimizing the outcomes of the operation as it allows a preliminary study of the bone loss and an evalutation of feasibility of the surgery, it improves the precision of the positioning of the implant, especially in the context of severe deformity and bone loss, and it reduces the operating time; by improving surgeon training; by increasing patient involvement in decision making and informed consent.

3D technology, by offering targeted and customized solutions, is a valid tool to obtain the tailored care that every patient needs and deserves, also providing the surgeon with an important help in cases of great complexity.

In a clinical setting, there is a need for simple gait kinematic measurements to facilitate objective unobtrusive patient monitoring. The objective of this study is to determine if a learned classification model's output can be used to monitor a person's recovery status post-TKA.

The gait kinematics of 20 asymptomatic and 17 people with TKA were measured using a full-body Xsens model¹. The experimental group was measured at 6 weeks, 3, 6, and 12 months post-surgery. Joint angles of the ankle, knee, hip, and spine per stride (10 strides) were extracted from the Xsens software (MVN Awinda studio 4.4)¹.

Statistical features for each subject at each evaluation moment were derived from the kinematic time-series data. We normalised the features using standard scaling². We trained a logistic regression (LR) model using L1-regularisation on the 6 weeks post-surgery data2–4.

After training, we applied the trained LR- model to the normalised features computed for the subsequent timepoints. The model returns a score between 0 (100% confident the person is an asymptomatic control) and 1 (100% confident this person is a patient). The decision boundary is set at 0.5.

The classification accuracy of our LR-model was 94.58%. Our population's probability of belonging to the patient class decreases over time. At 12 months post-TKA, 38% of our patients were classified as asymptomatic.

Aims

To develop prediction models using machine-learning (ML) algorithms for 90-day and one-year mortality prediction in femoral neck fracture (FNF) patients aged 50 years or older based on the Hip fracture Evaluation with Alternatives of Total Hip arthroplasty versus Hemiarthroplasty (HEALTH) and Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trials.

Introduction and Objective

Several factors contribute to the duration of the hospital stay in patients that undergo to total hip arthroplasty (THA), either subjective or perioperative. However, no definite evidence has been provided on the role of any of these factors on the hospitalization length. The aim of this retrospective investigation is to evaluate the correlation between several preoperative and perioperative factors and the length of hospital stay (LOS) in patients that underwent elective total hip arthroplasty.

Introduction

Patients with FNF may be treated by either total hip arthroplasty (THA) or hemiarthroplasty (HA). Utilizing American Joint Replacement Registry (AJRR) data, we aimed to evaluate outcomes in FNF treatment.

Cellular therapies play an important role in tendon tissue engineering with tenocytes being described as the most prominent cell population if available in large numbers. However, in vitro expansion of tenocytes in standard culture leads to phenotypic drift and cellular senescence. Recent work suggests that maintenance of tenogenic phenotype in vitro can be achieved by recapitulating different aspects of the native tendon microenvironment. One approach used to modulate the in vitro microenvironment and enhance extracellular matrix (ECM) deposition is macromolecular crowding (MMC). MMC is based on the addition of inert macromolecules to the culture media mimicking the dense extracellular matrix. In addition, as tendon has been described to be a relatively avascular and hypoxic tissue and low oxygen tension can stimulate collagen synthesis and cross-linking, we venture to assess the synergistic effect of MMC and low oxygen tension on human tenocyte phenotype maintenance by enhancing synthesis and deposition of tissue-specific ECM.

Human tendons were kindly provided from University Hospital Galway, after obtaining appropriate licenses, ethical approvals and patient consent. Afterwards, tenocytes were extracted using the migration method. Experiments were conducted at passage three. Optimization of MMC conditions was assessed using 50 to 500 μg/ml carrageenan (Sigma Aldrich, UK). For variable oxygen tension cultures, tenocytes were incubated in a Coy Lab (USA) hypoxia chamber. ECM synthesis and deposition were assessed using SDS-PAGE (BioRad, UK) and immunocytochemistry (ABCAM, UK) analysis. Protein analysis for Scleraxis (ABCAM, UK) was performed using western blot. Gene analysis was conducted using a gene array (Roche, Ireland). Cell morphology was assessed using bright-field microscopy. All experiments were performed at least in triplicate. MINITAB (version 16, Minitab, Inc.) was used for statistical analysis. Two-sample t-test for pairwise comparisons and ANOVA for multiple comparisons were conducted

SDS-PAGE and immunocytochemistry analysis demonstrated that human tenocytes treated with the optimal MMC concentration at 2% oxygen tension showed increased synthesis and deposition of collagen type I, the major component of tendon ECM. Moreover, immunocytochemistry for the tendon-specific ECM proteins collagen type III, V, VI and fibronectin illustrated enhanced deposition when cells were treated with MMC at 2% oxygen tension. In addition, protein analysis revealed elevated dexpression of the tendon-specific protein Sclearaxis, while a detailed gene analysis revealed upregulation of tendon-related genes and downregulation of trans-differentiation markers again when cells cultured with MMC at 2% oxygen tension. Finally, low oxygen tension and MMC did not affect the metabolic activity, proliferation and viability of human tenocytes.

Collectively, results suggest that the synergistic effect of MMC and low oxygen tension can accelerate the formation of ECM-rich substitutes, which stimulates tenogenic phenotype maintenance. Currently, the addition of substrate aligned topography together with MMC and hypoxia is being investigated in this multifactorial study for the development of an implantable device for tendon regeneration.

Tissue engineering by self-assembly is a technique that consists of growing cells on surfaces made of thermoresponsive polymers, that allow the production of contiguous cell sheets by simply lowering the temperature below the polymer's low critical solution temperature. In this approach cell-cell junctions and deposited extracellular matrix (ECM) remain intact, which provides a better cell localisation at the site of injury. However, these systems lack the possibility to fabricate multi-layered and three-dimensional cell sheets that would better recapitulate native tissues. Moreover, the fabrication of ECM-rich cell sheets would be highly desirable. This limitation could be overcome by inducing macromolecular crowding (MMC) conditions. Herein we venture to fabricate electrospun thermoresponsive nanofibres to sustain the growth and detachment of ECM-rich tissue substitutes in the presence of a MMC microenvironment.

A copolymer of 85% poly-N-isopropylacrylamide and 15% N-tert-butylacrylamide (pNIPAAm/NTBA) were used for all experiments. To create aligned nanofibers, the polymer was electrospun and collected on a mandrel rotating at 2000 rpm. Human adipose derived stem cells (hADSC) were treated with media containing macromolecular crowders to enhance matrix deposition. Cell viability and morphology were assessed, and immunocytochemistry was conducted in order to estimate matrix deposition and composition. Adipogenic, osteogenic and chondrogenic assays were performed both with and without the presence of MMC. Non-invasive cell detachment was enabled by decreasing the temperature of culture to 10 °C for 20 minutes.

The electrospinning process resulted in the production of pNIPAm/NTBA fibres in the diameter range from 1 to 2 µm and an overall alignment of 80%. Cell viability, proliferation and metabolic activity revealed that hADSCs were able to grow on the thermoresponsive scaffold. The cells were able to detach as an intact cell sheet in presence of MMC. Moreover, it was demonstated that MMC, by a volume extrusion effect, enhances Collagen type I deposition, which is one of the main components of the ECM. Histological analysis revealed that in the presence of MMC the cells were able to self-assembled into three dimensional multi-layers. The cells were able to differentiate towards the osteogenic and adipogenic lineage in the presence of MMC. Interestingly we were able to fabricate three-dimensional chondrogenic cell sheet both with and without MMC. Collectively the pNIPAm/NTBA thermoresponsive fibres were able to sustain the growth and the detachment of ECM-rich multi-layered cell sheets.

The pNIPAm/NTBA fibres were able to successfully sustain growth and detachment of ECM-rich tissue equivalents. We believe that replacement, repair and restoration of tissue function can be accomplished best using cells that create their own tissue-specific extracellular matrix with a precision and stoichiometric efficiency still unmatched by man-made devices.

Introduction

Deep venous thrombosis (DVT) is a potentially serious complication after total hip (THA) and knee (TKA) arthroplasty, traditionally justifying aggressive prophylaxis with low molecular weight heparin (LMWH) or direct oral anticoagulants (DOA) at the cost of an increased risk of bleeding. However, fast-track procedures might reduce the DVT risk and decrease the cost-benefit ratio of the current recommendations. The objective of this study was to compare thrombotic and bleeding risk in an unselected population of elective THA and TKA with a fast-track procedure.

Aims

Prosthetic joint infection (PJI) remains the most severe complication of arthroplasty. Failure of intensive, long-term antibiotic treatment for PJI often requires removal of the implant. Antibiotic failure is thought to be caused by biofilm and persister formation. Novel anti-biofilm and anti-persister strategies are urgently needed. Here, we investigated the effects of several antimicrobial peptides on the bacteria within antibiotic-treated biofilms in an in vitro mature biofilm model on abiotic surfaces.

Purpose of the study and background

A 2011 Cochrane review concluded that spinal manipulative therapy (SMT) is no better than other interventions for reducing pain and improving function in chronic low back pain (CLBP). Using individual participant data (IPD) from trials has advantages, among others: a more precise estimate of the effect and the potential to identify moderators. Our objective was to assess the effect of SMT in adults with CLBP and to identify relevant moderators.

Introduction

Rotational or axial alignment is an important concept in total knee surgery. Malrotation of the femoral component can lead to patellofemoral maltracking, pain and stiffness. In reconstruction surgery of the knee, achievement of correct rotation is even more difficult because of the lack of anatomical landmarks. The linea aspera is often the only remaining landmark, but its reliability is questionable.

Aim

Orthopedic implant related surgical site infection (SSI) is a severe complication which represents an important challenge concerning to its treatment. Therefore, gram-negative orthopedic infections have recently become a global concern.

Aim

Obese patients are not only more likely to receive total joint arthroplasty, but are also more prone to postoperative complications. The most severe complication is a prosthetic joint infection (PJI), occurring two to four times more often in severely obese patients (BMI ≥ 35kg/m²) compared to non-obese patients. This higher risk for PJI may be attributed to higher glucose levels in case of diabetes mellitus, diminished wound healing or inadequate antibiotic prophylaxis. To ultimately improve the prevention measures for this specific patient category, we aimed to describe the clinical and microbiological characteristics of early acute PJI in severely obese patients.

Aim

Debridement, antibiotics and implant retention (DAIR) is a widely used treatment modality for early acute prosthetic joint infection (PJI). A preoperative risk score was previously designed for predicting DAIR failure, consisting of chronic renal failure (K), liver cirrhosis (L), index surgery (I), cemented prosthesis (C) and C-reactive protein >115mg/L (KLIC). The aim of this study was to validate the KLIC score in an external cohort.

Tissue engineering by self-assembly offers the possibility to fabricate contiguous cell sheets that are stabilised by intact cell-cell contacts and endogenously produced extracellular matrix (ECM) However, these systems lack the possibility to introduce topographical cues, that are fundamental for the organisation of many types of tissues. Herein we venture to fabricate aligned electrospun thermoresponsive nanofibres to sustain growth and detachment of ECM-rich living substitutes in the presence of a MMC microenvironment. A copolymer of 85% poly-N-isopropylacrylamide and 15% N-tert-butylacrylamide (pNIPAAm/NTBA) were used. To create aligned nanofibers, the polymer was electrospun and collected on a mandrel rotating at 2000 rpm. Human adipose derived stem cells (hADSC) were treated with media containing macromolecular crowders to enhance matrix deposition. Cell viability and morphology were assessed, and immunocytochemistry was conducted to estimate matrix deposition and composition. Non-invasive cell detachment was enabled by decreasing the temperature of culture to 10 °C for 20 minutes. The electrospinning process resulted in the production of pNIPAm/NTBA fibres in the diameter range from 1 to 2 µm and an overall alignment of 80%. Cell viability revealed that hADSCs were able to grow on the scaffold. The cells aligned on the fibres after 3 days and they were able to detach as intact cell sheets in presence of MMC. Moreover, it was demonstrated that MMC, by a volume extrusion effect, enhances collagen type I deposition, one of the main components of the ECM. Collectively the pNIPAm/NTBA fibres were able to successfully sustain growth and detachment of ECM-rich cell sheets.

Conventional marker based optical motion capture (mocap) methods for estimating the position and orientation (pose) of anatomical segments use assumptions that anatomical segments are rigid bodies and the position of tracking markers is invariant relative to bones. Soft tissue artefact (STA) is the error in pose estimation due to markers secured to soft tissue that moves relative to bones. STA is a major source of pose estimation error and is most prevalent when markers are placed over joints. Mocap and bi-plane videoradiography data were recorded synchronously while three individuals walked on a treadmill. For all three, pose of the thigh and shank, and movement of markers relative to the bones, were determined from the videoradiography data (DSX, C-Motion). Independently, pose of thighs and shanks was estimated using mocap data (Visual3D, C-Motion). Our measures of error in the mocap pose estimation were the relative thigh and shank translations. X-ray data from two subjects were used to generate a regression model for the antero/posterior movement of the lateral knee marker against internal/external hip rotation. The mocap translation errors of the third subject, attributed to STA of the knee marker, were 15.6mm and 32.0mm respectively. The pose of the third subject was then estimated using a probabilistic algorithm incorporating our regression model. Mocap translation errors were reduced to 10.6mm (thigh) and 4.4mm (shank). The results from these data suggest that errors in pose estimation due to STA may possibly be reduced via the application of algorithms based on probabilistic inference to mocap data.

Fabrication of biogenic coatings with suitable mechanical properties is a key goal in orthopedics, to overcome the limitations of currently available coatings and improve the clinical results of coated implants compared to uncoated ones. In this paper, biological-like apatite coatings were deposited from a natural bone-apatite source by a pulsed electron deposition technique (PED).

Bone apatite-like (BAL) films were deposited directly from bone targets, obtained by standard deproteinization of bovine tibial cortical shafts and compared to films deposited by sintered stoichiometric-hydroxyapatite targets (HA). Deposition was performed at room temperature by PED in the Ionized Jet Deposition (IJD) version. Half of the samples was annealed at 400°C for 1h (BAL_400 and HA_400). As-deposited and annealed coatings were characterized in terms of composition and crystallinity (XRD, FT-IR), microstructure and morphology (SEM-EDS, AFM) and mechanical properties (nanoindentation and micro-scratch). For the biological tests, human dental pulp stem cells (hDPSCs) were isolated from dental pulp from patients undergoing a routine tooth extraction, plated on the samples (2500 cells/cm2) and cultured for 3 weeks, when the expression of typical osteogenic markers Runx-2, osteopontin, Osx and Osteocalcin in hDPSCs was evaluated.

Results showed that deposition by PED allows for a close transfer of the targets” composition. As-deposited coatings exhibited low cristallinity, that was significantly increased by post-deposition annealing, up to resembling that of biogenic apatite target. As a result of annealing, mechanical properties increased up to values comparable to those of commercial plasma-sprayed HA-coatings.

In vitro biological tests indicated that BAL_400 promotes hDPSCs proliferation to a higher extent compared to non-annealed bone coating and HA-references. Furher, immunofluorescence and western blot analyses revealed that the typical osteogenic markers were expressed, indicating that BAL_400 alone can efficiently promote the osteogenic commitment of the cells, even in absence of an osteogenic medium.

In conclusion, bone-like apatite coatings were deposited by PED, which closely resembled composition and structure of natural-apatite. Upon annealing at 400°C, the coatings exhibited satisfactory mechanical properties and were capable of providing a suitable microenvironment for hDPSCs adherence and proliferation and for them to reach osteogenic commitment.

These results suggest that bone apatite-like thin films obtained by biogenic source may represent an innovative platform to boost bone regeneration in the orthopedic, maxillofacial and odontoiatric field.

Background

The goal of this study was (1) to investigate the relationships between the bony contours of the knee and the popliteus tendon before and after TKA and (2) to analyse the influence of implant sizing. Our hypothesis was that an apparently well-sized prosthesis, will modify the position or the tracking of popliteus tendon.

Introduction

Systemic metal ion monitoring (Co;Cr) has proven to be a useful screening tool for implant performance to detect failure at an early stage in metal-on-metal hip arthroplasty. Several clinical studies have reported elevated metal ion levels after total knee arthroplasty (TKA), with fairly high levels associated with rotating hinge knees (RHK) and megaprostheses¹. In a knee simulator study, Kretzer², demonstrated volumetric wear and corrosion of metallic surfaces. However, prospective in vivo data are scarce, resulting in a lack of knowledge of how levels evolve over time. The goal of this study was to measure serum Co and Cr levels in several types TKA patients prospectively, evaluate the evolution in time and investigate whether elevated levels could be used as an indicator for implant failure.

To determine the mechanisms and extents of popliteus impingements before and after TKA and to investigate the influence of implant sizing. The hypotheses were that (i) popliteus impingements after TKA may occur at both the tibia and the femur and (ii) even with an apparently well-sized prosthesis, popliteal tracking during knee flexion is modified compared to the preoperative situation.

The location of the popliteus in three cadaver knees was measured using computed tomography (CT), before and after implantation of plastic TKA replicas, by injecting the tendon with radiopaque liquid. The pre- and post-operative positions of the popliteus were compared from full extension to deep flexion using normosized, oversized and undersized implants (one size increments).

At the tibia, TKA caused the popliteus to translate posteriorly, mostly in full extension: 4.1mm for normosized implants, and 15.8mm with oversized implants, but no translations were observed when using undersized implants. At the femur, TKA caused the popliteus to translate laterally at deeper flexion angles, peaking between 80º-120º: 2.0 mm for normosized implants and 2.6 mm with oversized implants. Three-dimensional analysis revealed prosthetic overhang at the postero-superior corner of normosized and oversized femoral components (respectively, up to 2.9 mm and 6.6 mm).

A well-sized tibial component modifies popliteal tracking, while an undersized tibial component maintains more physiologic patterns. Oversizing shifts the popliteus considerably throughout the full arc of motion. This study suggests that both femoro- and tibio-popliteus impingements could play a role in residual pain and stiffness after TKA.

Systemic metal ion monitoring (Co;Cr) has proven to be a useful screening tool for implant performance to detect failure at an early stage in metal-on-metal hip arthroplasty. Several clinical studies have reported elevated metal ion levels after total knee arthroplasty (TKA), with fairly high levels associated with rotating hinge knees (RHK) and megaprostheses¹. In a knee simulator study, Kretzer², demonstrated volumetric wear and corrosion of metallic surfaces. However, prospective in vivo data are scarce, resulting in a lack of knowledge of how levels evolve over time. The goal of this study was to measure serum Co and Cr levels in several types TKA patients prospectively, evaluate the evolution in time and investigate whether elevated levels could be used as an indicator for implant failure.

The study was conducted at Ghent University hospital. 130 patients undergoing knee arthroplasty were included in the study, 35 patients were lost due to logistic problems. 95 patients with 124 knee prostheses had received either a TKA (primary or revision) (69 in 55 patients), a unicompartimental knee arthroplasty (7 UKA), a RHK (revision −7 in 6 patients) or a megaprosthesis (malignant bone tumours − 28 in 27 patients). The TKA, UKA and RHK groups were followed prospectively, with serum Co and Cr ions measured preoperatively, at 3,6 and 12 months postoperatively. In patients with a megaprosthesis, metal ions were measured at follow-up (cross-sectional study design).

In primary knees, we did not observe an increase in serum metal ion levels at 3, 6 or 12 months. Two patients with a hip arthroplasty had elevated preTKA Co and Cr levels. There was no difference between unilateral and bilateral knee prostheses. In the revision group, elevated pre-revision levels were found in 2 failures for implant loosening. In both cases, ion levels decreased postoperatively. In revisions with a standard TKA, there was no significant increase in metal ions compared to primary knee arthroplasty. RHK were associated with a significant increase in Co levels even at short-term (3–12 months). The megaprosthesis group had the highest metal ion levels and showed a significant increase in Co and Cr with time in patients followed prospectively. With the current data, we could not demonstrate a correlation between metal ion levels, size of the implant or length of time in situ.

In primary knee arthroplasty with a standard TKA or UKA, metal ion levels were not elevated till one year postoperatively. This suggests a different mechanism of metal ion release in comparison to metal-on-metal hip arthroplasties. In two cases of revision for implant loosening, pre-revision levels were elevated, possibly associated with component wear, and decreased after revision. With RHK, slightly elevated ion levels were found prospectively. Megaprostheses had significantly elevated Co and Cr levels, due to corrosion of large metallic surfaces and/or wear of components which were not perfectly aligned during difficult reconstruction after tumour resection. Further research is needed to assess the clinical relevance of metal ion levels in knee arthroplasty.

Introduction

Failure of the polyethylene glenoid component is the most common complication of Total Shoulder Arthroplasty (TSA) and accounts for a majority of the unsatisfactory results after this procedure. Nowadays, most of the shoulder prostheses consist of metal on polyethylene bearing components. Repetitive contact between the metal ball and the polyethylene socket produces progressive abrasion of the implant if the moving part is made of polyethylene. Its debris may then lead to an active osteolysis and implant loosening. Failure of the glenoid component is often manifested clinically by pain, loss of function, and the presence of a clunking noise and leads to revision surgery.

The use of ceramic balls aims at the reduction of this phenomenon. In many studies regarding knee and hip replacement it has been shown that the use of ceramic on polyethylene (CoP) is more beneficial in terms of polyethylene wear and failure, when compared to metal on polyethylene (MoP).

Since a human shoulder is very different from a hip and a knee, it is not a self-centering, neither congruent joint. And its stability is provided by healthy muscles of the rotator cuff. We decided to compare CoP against MoP in semi- force controlled test setup. Where, for a given governing angular motion the translational motion was a function of contact (frictional) forces between the tested couple (humeral head and PE).

This is to our knowledge the first study to address in direct comparison wear in TSA in semi force controlled test setup.

Purpose

External rotation of the femoral component is one factor that favors a satisfactory clinical result. New technologies have been developed to precisely implant the components of a total knee arthroplasty, including computer-assisted surgery (CAS) and patient-specific instruments (PSIs). The aim of this study was to compare the precision of CAS and PSIs when determining the orientation of the femoral component.

Goals of the study

(1) to investigate the relationships between the bony contours of the knee and the Popliteus Tendon (PT) in the healthy knee and after implantation of a TKA and (2) to analyze the influence of implant sizing.

Introduction

Obesity is known to influence surgical risk in total hip replacement (THR), with increased Body Mass Index (BMI) leading to elevated risk of complications and poorer outcome scores. Using a multinational trial data of a single implant, we assess the impact of BMI and regional variations on Harris Hip scores (HHS).

Aim

Fractures are the second commonest presentation of non-accidental injury (NAI) in children. Approximately one third of abused children will present to Acute Trauma Services (ATS) with fractures. Any cases of suspected child maltreatment should be referred to Safeguarding Services for follow-up, as outlined by Trust Guidelines. Our aim was to examine the referral of children with suspicious fractures to safeguarding and assess if cases with high risk of abuse are being missed by ATS.

Introduction

Assessment for and treatment of osteoporosis is recommended following hip fracture. All forms of osteoporosis treatment require an adequate calcium intake and normal vitamin D levels. This study assesses vitamin D levels in patients with hip fractures and describes guidelines on how to manage low vitamin D levels with high dose oral vitamin D3 (cholecalciferol).

Purpose

compare the radiological results in sagittal balance correction obtained with pedicle subtraction osteotomy (PSO) versus anterior-posterior osteotomy (APO) by double approach in adults.

Despite proven advantages, pulsatile lavage seems to be used infrequently during preparation in cemented total knee arthroplasty. This remains irritating, as the technique has been suggested to improve radiological survival in cemented TKA, where aseptic loosening of the tibial component represents the main reason for revision. Furthermore, there may be a potential improvement of fixation strength for the tibial tray achieved by increased cement penetration. In this study, the influence of pulsed lavage on mechanical stability of the tibial component and bone cement penetration was analyzed in a cadaveric setting. Six pairs of cadaveric, proximal tibia specimen underwent computed tomography (CT) for assessment of bone mineral density (BMD) and exclusion of osseous lesions. Following surgical preparation, in one side of a pair, the tibial surface was irrigated using 1800ml normal saline and pulsatile lavage, while in the other side syringe lavage using the identical amount of fluid was applied. After careful drying, bone cement was hand-pressurized on the bone surface, tibial components were inserted and impacted in an identical way. After curing of cement, specimen underwent a postimplantation CT analysis). Cement distrubution was then assessed using a three-dimenionsional visualization software. Trabecular bone, cement and implant were segmented based on an automatic thresholding algorithm, which had been validated in a previous study. This allowed to determine median cement penetration for the entire cemented area. Furthermore, fixation strength of the tibial trays was determined by a vertical pull-out test using a servohydraulic material testing machine. Testing was performed under displacement control at a rate of 0,5mm/sec until implant failure. Data was described by median and range. Results were compared by a Wilcoxon matched pairs signed rank test with a type 1 error probability of 5 %. Median pull-out forces in the pulsed lavage group were 1275N (range 864–1391) and 568N (range 243–683) in the syringe lavage group (p=0.031). Cement penetration was likewise increased (p=0.031) in the pulsed lavage group (1.32mm; range 0.86–1.94), when compared to the syringe irrigated group (0.79mm; range 0.51–1.66). Failure occurred in the pulsatile lavage group at the implant-cement interface and in the syringe lavage group at the bone-cement interface, which indicates the weakness of the latter. Altogether, improved mechanical stability of the tibial implant and likewise increased bone cement interdigitation could be demonstrated in the current study, when pulsed lavage is implemented. Enhanced fixation strength was suggested being a key to improved survival of the implant. If this is the case, pulsatile lavage should be considered being a mandatory preparation step when cementing tibial components in TKA.

Purpose

To document the success rate of closed reduction and soft tissue release in the treatment of bilateral true dislocation in developmental dysplasia of the hip (DDH).

Purpose

To document the incidence and nature of complications associated with hemiepiphysiodesis using a screw and plate device (8-plate, Orthofix).

Background and purpose

Sleep disturbance is frequently reported by people with chronic low back pain (CLBP >12 weeks), but there is limited knowledge of their sleep quality compared to healthy people. While disturbed sleep influences patients' mood, quality of life and recovery, few studies have comprehensively investigated sleep in CLBP. This study investigated differences in sleep profiles of people with CLBP, compared to age- and gender matched controls over seven consecutive nights.

Background: Chromosomal translocation are frequently observed in leukemias and sarcomas; these translocations break specific genes in the involved chromosomes and create novel chimeric genes that encode a fusion protein. Advances in these techniques have increased knowledge of the genes involved in tumoral development; molecular techniques have enabled more precise diagnosis as well as identification of new prognostic factors.

Aims: To explore the use of Reverse-Transcriptase Poly-merase Chain Reaction (RT-PCR) assay for detecting fusion transcripts in a series of Soft Tissue Sarcomas (STS) and compare the results with histopathologic diagnosis.

Material and methods: We studied 80 biopsies performed at Orthopaedic Oncology and Reconstructive Surgery Department, CTO-CFR-M.Adelaide Hospital Turin Italy, with clinical suspect of STS. Histological diagnosis was obtained contemporary to evaluation of chimeric transcripts detected by RT-PCR. cDNA were PCR amplified using primer specific for each sarcoma. Paraffin-embedded tissue samples were not used because the poor quality of the extracted RNA may give wrong positive results. Results Histology confirmed 21 Ewing Sarcoma (ES), 14 Synovial sarcoma (SS), 7 Mixoid liposarcoma (M-LPS), 4 Extraskeletal Myxoid Chondrosarcoma (E-MCDS), 4 Dermatofibrosarcoma protuberans (DFSP), 10 Rhabdo-myosarcoma, 10 Leiomyosarcoma. Of the 21 tumors diagnosed as ES, 21 (100%) expressed EWS-FLI1 chimeric transcripts. All 14 SS were positive for SYT-SSX fusion transcripts. Of the 7 cases with diagnosis of M-LPS, six were positive for EWS-CHOP transcripts; of the four cases of E-MCS 3 were positive for EWS-CHN fusion transcripts. All 4 DFSP were positive for COL1A1-PDGFB transcripts. Expression of Myo-D1, tested in ten cases of Rhabdomyosarcoma, was positive while in ten cases of Leiomyosarcoma no expression of Myo-D1 was detected by RT-PCR Ten cases were non sarcoma and negative for molecular biology.

Conclusion These results demonstrate a strong concordance between the standard histopathological diagnosis and molecular results. These techniques could be a useful method to increase the quality of histologic diagnosis in difficult cases.

Backgroud: Leiomyosarcoma (LMS) is characterized by malignant smooth muscle cells. LMS are principally tumours of adult life, children rarely develop these tumours. The cause of LMS is not understood, however the genetic alterations are thought to be important, if not inciting, in the formation and progression of sarcoma. The silencing of tumour suppressor genes by promoter hypermethylation is a common feature among many types of malignancies; it has been proposed that DNA methylation provides an alternative pathway to gene mutation.

Aims: To evaluate the promoter methylation in LMS: two tumour-related genes (MGMT and RASSF1A) were studied.

Materials and methods: 14 LMS specimens were obtained from patients treated at Orthopaedic Oncology and Reconstructive Surgery Department, CTO-CFR-M.Adelaide Hospital, Turin. Genomic DNA was extracted from paraffin sections and frozen samples according to standard protocols. Transformation of the methylations patterns in the CpG island of RASSF1A and MGMT of DNA were determined by chemical modification. To analyzed the role of aberrant DNA in LMS, methylation status by SP-PCR was evaluated. PCR products were amplified by unmethylated (U) and methylated (M)-specific primers.

Results: The RASSF1A promoter was methylated in 4 (29%) LMS, MGMT promoter was methylated in 2 (15 %); 1 of these patients with methylation had both RASSF1A and MGMT. Eight LMS samples did not show any methylation.

Conclusions: Our data indicate that inactivation of RASSF1A is a common event in LMS. Aberrant methylation of the RASSF1A promoter region is one of the most frequent epigenetic inactivation events detected in human cancer and leads to silencing of RASSF1A; moreover inactivation of RASSF1A was usually associated to poor prognosis. According to recent reports, that demonstrated that promoter hypermethylation of the MGMT gene is not a frequent event in LMS, the present study detected MGMT in 2 (15%) tumour samples.

Cadeveric studies showed that single bundle ACL reconstructions were successful in limiting anterior tibial translation but were insufficient to control a combined rotatory load of internal and valgus torque. One possible cause of these condition could be that current single bundle procedures cannot realistically reproduce the complex anatomy of the ACL, especially the different function of its anteromedial(AM)and posterolateral(PL)bundle. The hypothesis of our study is that the addition of the PL bundle to the AM bundle, in an “in vivo” double bundle computer assisted ACL reconstruction, is actually able to reduce the internal rotation of the tibia at 30° degrees of knee flexion. Computer assisted ACL reconstruction has been used because it could be very effective in evaluating the global performance of the reconstructed knee.

Ten consecutive doble bundle ACL reconstructions were performed in our Hospital using hamstrings graft and the 2.0OrthoPilot-B. Braun-Aesculap ACLnavigation system. The average age of patients was 27.8 years.

The double-looped semitendinosus tendon replicating the AM bundle was fixed first at 60° of knee flexion. Than the gracilis tendon replicating the PL bundle was fixed at 15° of knee flexion. Maximum manual A–P displacement at 30° of flexion, maximum internal and external rotation of the knee were evaluated using the navigation system before surgery and after single(A–M)and double (AM+PL)bundle reconstruction. Statystical anlisys was done using paired T-test.

Before ACL reconstruction mean manual maximum AP displacement was 17.2mm;mean manual maximum internal rotation was 19.8mm and mean manual maximum external rotation was 16.8mm. After AM bundle reconstruction mean manual maximum AP displacement was 6.1mm;mean manual maximum internal rotation was 17.0mm and mean manual maximum external rotation was 16.3mm. After AM+PL bundles reconstruction mean manual maximum AP displacement was 5.3mm;mean manual maximum internal rotation was 16.2mm and mean manual maximum external rotation was 14.6mm. There was no statistically significant difference in the tibial internal rotation at 30° after single bundle(AM)and double bundle(AM+PL)reconstruction.

In this study the effectiveness of the PL bundle in controlling the internal rotation of the tibia, responsible of rotational instability of the knee, was evaluated in “in vivo” ACL reconstruction. The navigator system allowed us to obtain “in vivo” the real and correct value of AP displacement and internal and external rotation of the tibia before and after reconstruction.

Our hypothesis that the addition of the PL bundle to the AM bundle is actually able to reduce the internal rotation of the tibia at 30° degrees of knee flexion, minimizing the pivot shift phenomenon, on the basis of our study has not been confirmed.

Introduction: The mini C arm is a surgeon operated fluoroscopic device for use in the operating theatre for extremity orthopaedic surgery. There have been no studies comparing the radiation dose of the mini C arm and the conventional C arm.

The aim of this study was to determine if the exposure to patient and surgeon was decreased with use of the mini C arm.

Methods: This was a case-control study. Operations performed with the mini C arm were matched for type, complexity and operator with cases performed with the conventional C arm. The number of exposures and the total time of exposure were measured, and the skin dose and scatter calculated.

Results: There were 16 case-control pairs. There was a significantly greater number of exposures taken by the surgeon operated mini C arm (p=0.02), but there was still a significantly lower exposure to the surgeon with the mini C arm (p=0.004). There was no significant difference in the patient skin dose (p=0.21).

Conclusions: The surgeon operated mini C arm results in a greater exposure time and number of exposures. Despite this, the mini C arm exposes the surgeon to less radiation compared to the conventional C arm in extremity orthopaedics. The radiation exposure with the mini C arm is approximately half that of the conventional C arm. The increased number of exposures may occur because surgeons are more trigger happy with the mini C arm, or because there are technical problems with achieving a useful image. The mini C arm should be used for extremity orthopaedics whenever possible to decrease the radiation exposure.

Purpose of the study: The aim of this study was to analyze rotation of the normal and prosthetic distal femur as well as the spaces from 90 to 130 degrees flexion.

Material and methods: Torsion scans were obtained preoperatively and postoperatively for 44 total knee prostheses. The difference in femoral torsion between the pre- and postoperative image was used to assess the rotation in which the femoral component was implanted. The prostheses were divided into two groups: group I when the femoral implant was implanted with external rotation of more than 5°; group II when the femoral implant was implanted with external rotation less than 5°. A preoperative stress scan was obtained in 20 patients then repeated during the year following implantation. Stress images with knee flexion at angles from 90° to 130° were obtained. The patient was installed in the ventral supine position. 8mm scan slices were centered on the lower end of the femur, ten 50ms images were acquired during flexion movement from 90° to 130°. This enabled determination of the knee flexion axis preoperatively and postoperatively, to measure the variation in the epicondylar axis compared with the mechanical axis of the tibia between 90° and 130° flexion and finally to deduct change in the femorotibial space in flexion from 90° to 130°.

Results: The 18 total knee prostheses with a femoral component implanted with external rotation greater than 5° (group I) showed significantly greater range of flexion (p< 0.05) (mean 120°, range 110°–130°) than the 26 prostheses in group II with a femoral component implanted in external rotation less than 5° (mean 100°, range 80°–115°. For the 20 knees with stress scans, the preoperative images showed an epicondylar axis about 5° fro the mechanical axis of the tibia when the knee flexed in the 90°–130° range. After surgery, the stress scans showed that this epicondylar axis of rotation of the prosthesis-bearing knees occurred especially for knees with a wide range of flexion. The 20 knees with flexion limited to 100° did not present an epicondylar rotation axis compared with the mechanical axis of the tibia. The 15 knees with 125° flexion or more had an epicondylar axis of rotation after 90° flexion. Rotation of the epicondylar axis in relation to the mechanical axis of the tibia between 90° and 130° flexion was the consequence of a femorotibial space which changed in the medial and laeral femorotibial compartments between 90° and 130° flexion: after 90° flexion, the medial femorotibial space decreased and the lateral femorotibial space increased. This explains why movement from 90° flexion to 130° flexion was facilitated by placing the femoral piece in external rotation.

Discussion: Search for ligament balance for knee flexion above 90° is logical only if the goal is to obtain knee stability in extension and flexion at 90°. It is probably no rational if the goal is to allow the knee to reach flexion in the 120°–130° range. Ligament balance in flexion above 90° is important and should be maintained up through 130° flexion. The other solution is to empirically increase external rotation of the femoral component a few degrees in order to allow greater range of flexion.

Purpose of the study: The humeral head is the second most frequent localization of non-traumatic osteonecrosis. For certain etiologies, for example sickle-cell anemia, the frequency is similar to that observed for the femoral head. There have nevertheless been very few publications on this pathology and its treatment. The purpose of this study was to assess outcome in a series of 771 cases of humeral head osteonecrosis in order to establish the natural history of the disease, criteria predictive of outcome, and therapeutic options.

Material and methods: The diagnosis of osteonecrosis of the humeral head was established for 771 humeri in 424 patients between 1981 to 2000. Minimum follow-up was five years (maximum 23 and mean 13 years). Outcome was assessed in terms of the clinical course, specifically the need for surgery due to pain or functional impotency. The radiological assessment was made on serial AP and lateral views taken every year or two years. The extent of the osteonecrosis was assessed on the basis of the magnetic resonance imaging (MRI) findings when available (after 1985). The ARlet and Ficat classification established for the femoral head was adapted to the shoulder: grade I: osteonecrosis of the humeral head visualized solely with MRI; grade II: radiologically detectable osteonecrosis; grade III: subchondral dissection without loss of spherical shape: grade IV: loss of spherical shape without visible osteoarthritis: grade V: osteoarthritis.

Results: Bilateral osteonecrosis was observed in 82% of the 424 patients. This gave 771 cases of humeral head necrosis. There was no gender predominance. Mean age at diagnosis was 32 years (range 18–57 years). The most frequent etiology was sickle-cell anemia (307 patients), followed by corticosteroid therapy (80 patients). Other etiologies were much less frequent: alcohol abuse, Gaucher’s disease, hyperlipidemia. Osteonecrosis of the humeral head was generally associated with another localization, particularly involving the hip and the knee joints. Multifocal osteonecrosis was also a common finding. Among the patients whose dignosis of osteonecrosis was established before symptom onset (scintigraphy or MRI performed in patients with multifocal osteonecrosis), the natural history was on average three years between MRI diagnosis and onset of pain. For 46% of the cases, pain appeared at grade I, before the development of radiographic signs. In 54% of the cases, grade II occurred before pain. It took six years before all of the cases with osteonecrosis diagnosed in a non-symptomatic phase produced pain. Factors affecting the rapidity of the radiological course were: etiology, size of the necrotic focus, presence and rapidity of osteonecrosis in other localizations (hip and knee). The humeral head lost its spherical shape on average four to five years after the diagnosis of osteoarthritic degradation of the joint, at about seven to eight years of evolution. Among the 256 patients followed for more than ten years, 51% required surgery. These 131 operations were for: drilling with bone marrow grafting (grade I or II) (n=62), cimentoplasty after loss of spherical shape but before glenohumeral osteoarthritis (n=15), resection of sequestered necrosis after loss of spherical shape (n=12), shoulder arthroplasty (n=42).

Discussion and conclusion: This study demonstrated that the natural history of osteonecrosis of the humeral head has a poor long-term outcome. Shoulder arthroplasty is rarely required during the first decade of the disease. Other therapeutic alternatives can help avoid or retard the need for shoulder arthroplasty in these very young patients.

Purpose of the study: It is currently accepted that ligament balance should be one of the goals for total knee arthroplasty (TKA) and that this balance should be obtained by correct bone cuts or appropriate ligament procedures. There is however no standard way of assessing this balance. The purpose of this study was to define limit values for knee laxity observed in a series of normal knees and in a series of 54 TKA reviewed at more than ten years.

Material and methods: Laxity in extension of normal knees was measured on forced varus and valgus films using the contralateral knees of patients who had undergone knee surgery for osteotomy or prosthesis implantation. Laxity in extension of TKA knees was measured the first postoperative year and at last follow-up by measuring the decoaptation between the tibial and femoral pieces on single-leg stance films. The change in decoaptation over time was compared with the postoperative and last follow-up goniometry figures, the IKS knee score, the number of loosenings and the number of lucent lines. Multifactorial analysis was considered significant at p< 0.05.

Results: For the normal knees in extension, the medial compartment gap was 2 mm on average (range 1.5–3.5 mm) on the forced valgus images and the lateral compartment gap was 3 mm on average (range 2–4 mm) on the forced varus images. The corresponding angular value was 1° decoaptation on the forced valgus images and 1.5° on the forced varus images. Among the 54 knees with a TKA, the first postperative single-leg stance image revealed a lateral decoaptation _ 3° for 12 knees considered to present laxity, and was _ 2° for 42 knees considered not to present laxity. At last follow-up (13 years on average, range 11–14 years) the 42 knees without laxity remained unchanged without decoaptation, including the 34 normocorrected knees (±3°) and the eight undercorrected knees presenting more than 3° varus (mean undercorection 5°, range 3–7°). The 12 knees presenting postoperative radiographic decoaptation _ 3° showed at last follow-up a significant increase in laxity (p< 0.05) and 2.5° further increase in decoaptation. The increase in decoaptation occurred on normocorrected (n=7) or undercorrected (n=5) knees. This increase in decoaptation was greater with greater residual genu varum. Four groups of knees could be distinguished: normocorrected and stable; normocorrected and unstable; undercorrected and stable; overcorrected and unstable. The number of loosenings requiring revision and the number of progressive lucent lines were significantly greater among unstable knees (two loosenings, and five progressive lucent lines) than among stable knees (no loosening or lucent lines). They were also greater in the group of normocorrected and unstable knees (one loosening and two lucent lines) than in the group of undercorrected and stable knees (no loosening or lucent line). The IKS knee score of stable knees was higher than that of unstable knees irrespective of the correction (p< 0.05).

Discussion: Postoperative laxity in varus with angular decoaptation greater than 3° corresponds to a lateral compartment gap and should be avoided even if the knee is properly aligned postoperatively. If the knee is stable, moderate undercorrection (3–5° varus) does not appear to have an unfavorable long-term effect on knee laxity or on the femoral and tibial pieces.

Conclusion: For knees with constitutional genu varum, moderate undercorrection with a stable knee is preferable to normocorrection at the cost of lost stability.

Background: The Mini C-arm has been heralded as a safer means of fluoroscopy. No clinical data on the use of mini C-arm is available in the literature.

Aim: The purpose of this study was to compare the exposure in clinical practice from the conventional C-arm and the Mini C-arm and scrutinize patterns of exposure.

Materials/methods: Case-Control design. All operations using the mini C-arm were reviewed. Control cases were identical operations using the conventional C-arm. The Sign test was used to detect the number of exposures taken and the dose of radiation.

Results: There were 16 operations with valid case-control pairs. The number of exposures performed was significantly greater for the mini C-arm (p=0.05), but the emitted dose of radiation was significantly smaller (p< 0.001) for the mini C-arm.

Conclusions: The mini C-arm is a safer device for extremity surgery, but the surgeon should be careful to avoid excessive exposures.

Objective: The purpose of this study was to evaluate the effectiveness of surgical reconstruction of posttraumatic deformity. Posttraumatic kyphosis (PTK) causes pain, neurological deficit, sagittal imbalance, progressive deformity, cosmetic and functional deterioration. Its treatment is cause of controversy and technically demanding. There are few reviews in the literature about the results of its surgical treatment.

Methods: From 1995 to 2002 twenty-one patients suffering from posttraumatic thoracolumbar kyphosis were operated. The average follow-up was 3.9 years (range 6 – 1 years). The average age was 38 years (range 23–62): 13 female and 8 male. All patients complained about vertebral pain, 16 located at the apex of the deformity, 2 patients in the lumbar area and 3 patients referred also pain above the lesion. Three patients had irradiated circumferential pain and 4 patients mild neurological deficit. Two patients showed sexual dysfunction. In one patient only anterior approach with allograft reconstruction and anterior plate fixation was performed. In 17 patients simultaneous or staged approach with posterior release, anterior discectomy and allograft reconstruction and posterior compressed instrumentation was performed. In three patients a posterior closing wedge osteotomy was performed

Results: Postoperative pain decreased from 7.5 to 2.8 (VAS). Functional status: preoperative 42.3 % and postoperative 13.8% (Oswestry score). There was no hardware failure. All cases showed solid fusion without significant loss of correction. The average corrected kyphosis was 27.3°. All patients were satisfied with their cosmetic result. No cavity drainage was performed in 2 patients with syringomielia. 1 of 4 patients with neurological deficit did not improve. Two patients had thoracic neuropathic postoperative pain; one of them needed pain clinic treatment until remission. One case had superficial infection. One patient showed a Chylous leakage.

Discussion: Only few works analyze the results of surgical treatment of PTK. The controvesrsy between anterior-aposterior surgery versus posterior closing wedge osteotomy depens of classification of posttraumatic spinal deformities based on three criteria: the region involved, the neurological status and the presence of any sagittal or frontal plane deformities outsides the local kyphosis

Conclusions: Our results suggest that the double approach with anterior allograft and posterior instrumentation shows clinical and radiological efficacy for sagittal posttraumatic deformity. In spite of surgical risk, there have been few complications with a high rate of patient satisfaction.

Study Design: To design and test a new questionnaire to assess depression and other mood states.

Summary of Background Data: Measurement of depression and of other mood states in pain patients has been criticised in recent years on the grounds that most questionnaires were not developed in pain populations and suffer from criterion contamination by somatic items. In addition, there is no accepted measurement for positive emotions which are more than the absence of depression.

Objective: To develop a reliable and brief tool to assess mood in pain patients.

Method: Non-somatic items concerning depression, anxiety and positive outlook were extracted using exploratory factor analysis from commonly used instruments (Beck Depression Inventory and Hospital Anxiety and Depression Scale) completed by over 900 chronic pain patients. Confirmatory factor analysis was used to test the internal structure of the final item set. Items were then reworded and presented as a new questionnaire (the Depression, Anxiety and Positive Outlook Scale: DAPOS) to two new samples: patients attending pain management and patients attending osteopathy. The new questionnaire was compared with several well-known questionnaires (SF-36, BDI, PCS). The structure was calibrated and tested using confirmatory factor analysis on both samples. Finally, a sub-set of patients carried out a sorting task to test for face validity.

Results and conclusion: The DAPOS performed well, indicating that it is a reliable measure of the three mood states with good initial evidence of validity in these samples.

The purpose of this paper is to investigate the relative contribution of each component in the ultimate strength and stiffness of the Evolgate (Citieffe), which is presently a widely used fixation device in DGST ACL reconstruction. The three components of the Evolgate were tested using fresh frozen animal tissue stored at −20° Celsius. Common extensor tendons were harvested from 20-month-old bovine forelimbs. Twenty-four tests were performed for each of the following configurations: six tests using Evolgate complete, six tests using screw alone, six tests using screw and washer and six tests using screw and coil. A randomised t-test was used; differences were considered significant when p< 0.05. The mean strength was: Evolgate complete 1314±194N; coil and screw 700±152N; screw alone 408±86N; and screw and washer 333±93N. There was a significant difference between fixation strength of Evolgate and the other devices, none between screw alone and screw and washer. The mean slippage of the Evolgate was significantly lower than the other devices. The mean stiffness of the Evolgate (269±14 N/mm) was significantly greater than the other devices. On the basis of the results of the present study, the coil appears to be the most important component of the Evolgate, resulting in a significant increase of the fixation strength of the screw. However, it is important to note that, as the washer alone does not improve the strength of the screw, if a washer is associated with a coil a further significant increase in strength and stiffness of the device is observed.

The purpose of this study is to biomechanically evaluate how four different fixation devices (two femoral and two tibial) associated in three different combinations, using cyclic loading with final pull-out test, affect the strength and the stiffness of the femur-graft-tibia complex.

We conducted a controlled laboratory study and tested, using cyclic loading with final pull-out, two femoral devices (Swing- bridge and Endobutton CL) and two tibial device (Evolgate and BioRCI screw) in three different combinations: Group A, EB-Bio RCI; Group B, EB-Evolgate; and Group C, SB- Evolgate.

We used porcine knees and bovine digital extensor tendons and evaluated the stiffness and strength at the final pull-out, and the displacement at the 1st, 100th, 300th, 500th and 1000th cycle.

A t-test was used for statistical evaluation.

There was a statistically significant difference in ultimate failure load between group A and group B (p=0.03) and group A and group C (p=0.0007) but no difference between group B and group C (p=0.72). There was a statistically significant difference in ultimate failure load between group A and group C (p=0.02) and group B and group C (p=0.01) but no difference between group A and group B (p=0.88).

Due to the biomechanical properties of the F-G-T complex the combination of Swing-Bridge and Evolgate seems to be a good alternative when an accelerated post-operative rehabilitation is planned after ACL reconstruction using DGST.

Maintenance of the bone stock is a primary goal in hip surgery. The idea of a resurfacing hip prosthesis had already been proposed in the past without success. The improvement in prosthetic materials, however, has mades it possible to reconsider the use of resurfacing prostheses. We report our experience with the Birmingham hip resurfacing (BHR) prosthesis.

We operated on 58 patients (60 hips, two bilaterally), 31 men, 27 women, with a mean age of 47.9 years (25–76) and a mean follow-up of 27 months (1–42). We used the posterolateral approach with the patient in lateral decubitus. We performed a clinical and radiographic examination before surgery and at 1 and 6 months postoperatively. We recorded a statistically significant improvement in the clinical score at 6 months after surgery, with respect to the preoperative examination. Major complications were two fractures of the femoral neck and one infection. We recorded also peri-prosthetic calcifications in two patients, calcifications of the ileopsoas in two and ileopsoas tendinitis in one.

In conclusion, in our experience, the BHR prosthesis reproduced the biomechanics of the hip and minimised the risk of luxation. The preliminary clinical results are encouraging, also for difficult cases.

The purpose of our study was to determine the effect of 4 weeks and 12 weeks of implantation on the strength of a tendon graft in a bone tunnel using a low-profile fixation device, Evolgate, in an extra-articular ovine model. Moreover, we evaluated the histological changes.

The common digital extensor tendon was detached from the lateral femoral condyle and fixed with the Evolgate device in a 30-mm-long tunnel placed obliquely across the dense metaphyseal bone of the proximal tibia. We performed either biomechanical or histological study. Three sheep were sacrified at time 0 and their posterior limbs were used for biomechanical tests. Six sheep were used for biomechanical tests at time 1 (4 weeks) and at time 2 (12 weeks). The other three sheep were used for histological evaluation after 4 and 12 weeks of implantation. The biomechanical tests included a 50 N preload applied for 10 s and a cyclic load test in 50-N increments until failure to evaluate the ultimate failure load. We used a paired t-test to evaluate the difference between group at T1 and group at T2 with the control group at time 0, respectively. Tests were performed using an electromechanic machine (Zwick-Roell Z010, Zwick-Roell, Ulm, Germany). Data were recorded with dedicated software (Textexpert 8.1, Zwick-Roell).

The biomechanical results show an improvement of about 50% in strength after 4 and 12 weeks post-implantation, respectively. The histological evaluation shows a layer of cellular, fibrous tissue between the tendon and the bone, along the length of the bone tunnel; this layer progressively matured and reorganised during the healing process. The collagen fibres that attached the tendon to the bone resembled Sharpey fibres.

The strength of the interface was noted to have significantly and progressively increased between the second and the 12th week after the transplantation. The progressive increase in strength was correlated with the degree of bone ingrowth, mineralisation, and maturation of the healing tissue, noted histologically.

The use of conventional stems in hip arthroplasty may be difficult in cases of dysplasia, coxa vara or coxa valga, after fracture or proximal femur osteotomy. In fact the morphologic alterations of the proximal femur might require prosthetic components characterised by small size and different neck angles to restore correct joint biomechanics. In these cases we are often compelled to compromise between the ideal implant aneiversion and fit and what we can really achieve. An alternative to conventional prostheses is represented by custom-made prostheses.

For 3 years we have been using the Modulus stem in the treatment of morphologic disorders of the hip. The conic shape of the stem easily fits the different morphologies of the proximal femur, whereas the modularity of the neck makes it possible to correct length, inclination and declination of the femural neck. We studied 59 patients by clinical and radiographic examination before surgery and 1, 3, 6 and 12 months postoperatively. We recorded a statistically significant improvement in the clinical score already at 1 month but this was even better at 6 months after surgery, with respect to the pre-operative examination.

With the use of this prosthesis, the recovery of correct joint biomechanics together with high tribologic standards could improve the implant survival, leading to cost reduction and patient satisfaction.

Secure tendon-to-bone fixation is essential for successful rotator cuff repair. Thus, the biomechanical properties of devices used in rotator cuff repair should be better understood. This controlled laboratory study was performed to evaluate response to incremental cyclic loading of six different anchor-wire complexes commonly used in rotator cuff repair.

Two absorbable anchors 5 and 6.5 mm in diameter and one metallic anchor, coupled with both ethibond or fibrewire (FW) were tested on five pairs of fresh-frozen human cadaveric shoulders. An incremental cyclic load was applied until failure using a Zwich-Roell Z010 electromechanical testing machine. The ultimate failure load and mode of failure were recorded. A t-test was used for statistical analysis.

The FW suture coupled both with absorbable and metallic anchors provides a statistically significant stronger fixation. However, while the metallic anchors in most cases fail due to the slippage of the anchor, absorbable anchors fail due to rupture of the loop. The FW seems to increase the strength of fixation devices under cyclic load both using absorbable or metallic anchors with relevant differences in failure mode (slippage of the metallic anchor and loop failure in absorbable ones). Using a FW suture, the risk of metallic anchor migration might increase.

The increase in knee arthroscopy performed on an out-patient basis, along with the need for cost reduction and a safe and rapid patient discharge, has underlined the importance of adequate anaesthesia techniques. We designed this study to compare efficacy, efficiency and surgeon’s satisfaction of total intravenous anaesthesia with propofol and remifentanil with those of spinal or peripheral nerve blocks for outpatient knee arthroscopy.

A total of 120 patients undergoing elective outpatient knee arthroscopy were randomly allocated to receive total intravenous anaesthesia with propofol and remifent-anil (n=40), combined sciatic-femoral nerve block (n=40) or spinal anaesthesia (n=40). Preparation times, surgeon’s satisfaction, discharge times and anaesthesia-related costs with the three anaesthesia techniques were analysed.

Preparation time was shorter with general anaesthesia (13 min) than with spinal anaesthesia or sciatic-femoral block (15 min; p=0.006). Surgeon’s satisfaction was similar in the three groups. Furthermore, 17 patients receiving peripheral nerve block (42%) and 12 receiving spinal anaesthesia (30%) by-passed the post-anaesthesia care unit after surgery as compared with only two general anaesthesia patients (5%; p=0.01). Discharge from the post-anaesthesia care unit was more rapid after peripheral block; however, stay in the Day Surgery Unit was shorter after general anaesthesia than peripheral or spinal blocks (p=0.026). Urinary retention was reported in three spinal anaesthesia patients only (8%; p=0.03).

Regional anaesthesia techniques reduce the rate of admission and the duration of stay in the post-anaesthesia care unit as compared with general anaesthesia. Peripheral rather than spinal nerve blocks should be preferred to minimise the risk of urinary retention.

Aims: To identify the incidence of neurological deþcit and functional outcome following displaced acetabular fractures. Methods: We carried out a prospective study of 136 patients who underwent skeletal stabilization of displaced acetabular fractures. Patients with sciatic nerve injuries were identiþed, assessed and followed up clinically. Routine EMG and nerve conduction studies were performed post-operatively on all cases with clinical proven neurological lesions to correlate the level, severity of the lesion and monitor progress of recovery. Results: 27 patients (19.8%) have neurological deþcit identiþed preoperatively. In 12 patients where the femoral heads were dislocated posteriorly. 20 were male and 7 were female. The mean age was 33.8 years (range 16–66). 15 patients had associated injuries but none of the patients had injury to the spinal cord. The mean ISS was 12.6 (range 9–34). The mean follow up was 3.4 years (range 1.5–6 years). 13 patients with complete drop foot at presentation. 9 patients had EMG proven double crush lesion. 3 patients had ipsilateral knee injury. 2 patients had intraopearative iatrogenic injury. All 9 patients with double crush syndrome have no improvement in function. Conclusions: Acetabular fractures associated with sciatic nerve injuries are devastating injuries with signiþcant long term morbidity. 50% patients showed improvement with time. Identiþcation of double crush lesion is vital as it is associated with poorer functional recovery as compared to single lesion.

Introduction and Objectives: This is a retrospective study on the treatment of lumbar degenerative disk disease (LDDD) using intervertebral arthroplasty. The lack of uniformity in the treatment of LDDD, persistence of pain even with solid fusion, and the possibility of changes over the fusion site have encouraged us to seek other solutions for this condition. Total intervertebral arthroplasty has been proposed as a possible alternative for selected cases of LDDD.

Materials and Methods: Between November 1999 and July 2002, 16 patients with LDDD were treated surgically using third-generation total intervertebral arthroplasty (Link SB Charité III) with a chromium-cobalt alloy and ultra-high molecular weight (UHMW) poly-ethylene. Average follow-up time was 14 months (6-36 months), and average age was 42 years (35–52). There were 11 females and 5 males. All patients underwent radi-olographic studies, CT scan, MRI, and discography (minimum 2 levels). Indications included LDDD of one to three segments, absence of root tension signs, absence of complete disc collapse, and iconography including concordant discography. LDDD was primary in 11 cases and post-discectomy in 5 cases. Surgery was indicated when at least 6 months of conservative treatment failed to yield results. Blood loss and length of hospital stay were compared to a similar group that underwent posterolateral arthrodesis. Pain, function, and degree of disability were evaluated before and after surgery using GEER (1999) instruments for the evaluation of degenerative lumbar pathology. Increase in height of the posterior intervertebral space and segmentary lordosis were also measured.

Results: Preoperative VAS: 7.8; postoperative VAS: 2.3. Disability index (Oswestry) was 41.3% preoperative and 10.8% postoperative. Average increase in height of posterior intervertebral space was 2.4mm, and mean segmental lordosis was 19.5°, which remained constant through the end of the follow-up period. Average hospital stay was 4.8 days (3–15) compared with 7.5 (5–18) for a group of patients who underwent suspended arthrodesis of L4–L5 with a much smaller quantity of blood loss. No infections were found. Complications: One patient developed an epidural haematoma, which was treated conservatively. Another developed a postoperative retroperitoneal haematoma, which was also treated conservatively. In neither case was there an adverse effect on the outcome of the procedure. One patient showed malpositioning of the prosthetic components on follow-up radiographs, with poor clinical progression at one year postoperative. The patient was treated with posterolateral fusion and right L5 foraminotomy. No infections were seen.

Discussion and Conclusions: Treatment of LDDD with intervertrebral arthroplasty was shown to be effective in the short term, if strict guidelines are followed. Aggressive surgical management is highly inferior to conventional arthrodesis. A longer follow-up period is needed to confirm the validity of this treatment. Technical error in malpositioning of the components in one case caused a poor result.