We test the clinical validity and financial implications of the proposed Choosing Wisely statement: “Using ultrasound as a screening test for shoulder instability is inappropriate in people under 30 years of age, unless there is clinical suspicion of a rotator cuff tear.”

A retrospective chart review from a specialist shoulder surgeon's practice over a two-year period recorded 124 patients under the age of 30 referred with shoulder instability. Of these, forty-one had already had ultrasound scans performed prior to specialist review. The scan results and patient files were reviewed to determine the reported findings on the scans and whether these findings were clinically relevant to diagnosis and decision-making. Comparison was made with subsequent MRI scan results. The data, obtained from the Accident Compensation Corporation (ACC), recorded the number of cases and costs incurred for ultrasound scans of the shoulder in patients under 30 years old over a 10-year period.

There were no cases where the ultrasound scan was considered useful in decision-making. No patient had a full thickness rotator cuff tear. Thirty-nine of the 41 patients subsequently had MRI scans. The cost to the ACC for funding ultrasound scans in patients under 30 has increased over the last decade and exceeded one million dollars in the 2020/2021 financial year. In addition, patients pay a surcharge for this test.

The proposed Choosing Wisely statement is valid. This evidence supports that ultrasound is an unnecessary investigation for patients with shoulder instability unless there is clinical suspicion of a rotator cuff tear. Ultrasound also incurs costs to the insurer (ACC) and the patient. We recommend x-rays and, if further imaging is indicated, High Tech Imaging with MRI and sometimes CT scans in these patients

Aim

While metagenomic (microbial DNA) sequencing technologies can detect the presence of microbes in a clinical sample, it is unknown whether this signal represents dead or live organisms. Metatranscriptomics (sequencing of RNA) offers the potential to detect transcriptionally “active” organisms within a microbial community, and map expressed genes to functional pathways of interest (e.g. antibiotic resistance). We used this approach to evaluate the utility of metatrancriptomics to diagnose PJI and predict antibiotic resistance.

Iliopsoas tendonitis occurs in up to 30% of patients after hip resurfacing arthroplasty (HRA) and is a common reason for revision. The primary purpose of this study was to validate our novel computational model for quantifying iliopsoas impingement in HRA patients using a case-controlled investigation. Secondary purpose was to compare these results with previously measured THA patients.

We conducted a retrospective search in an experienced surgeon's database for HRA patients with iliopsoas tendonitis, confirmed via the active hip flexion test in supine, and control patients without iliopsoas tendonitis, resulting in two cohorts of 12 patients. The CT scans were segmented, landmarked, and used to simulate the iliopsoas impingement in supine and standing pelvic positions. Three discrete impingement values were output for each pelvic position, and the mean and maximum of these values were reported. Cup prominence was measured using a novel, nearest-neighbour algorithm.

The mean cup prominence for the symptomatic cohort was 10.7mm and 5.1mm for the asymptomatic cohort (p << 0.01). The average standing mean impingement for the symptomatic cohort was 0.1mm and 0.0mm for the asymptomatic cohort (p << 0.01). The average standing maximum impingement for the symptomatic cohort was 0.2mm and 0.0mm for the asymptomatic cohort (p << 0.01). Impingement significantly predicted the probability of pain in logistic regression models and the simulation had a sensitivity of 92%, specificity of 91%, and an AUC ROC curve of 0.95.

Using a case-controlled investigation, we demonstrated that our novel simulation could detect iliopsoas impingement and differentiate between the symptomatic and asymptomatic cohorts. Interestingly, the HRA patients demonstrated less impingement than the THA patients, despite greater cup prominence. In conclusion, this tool has the potential to be used preoperatively, to guide decisions about optimal cup placement, and postoperatively, to assist in the diagnosis of iliopsoas tendonitis.

Aim

The efficacy of various irrigation solutions in removing microbial contamination of a surgical wound and reducing the rate of subsequent surgical site infection (SSI), has been demonstrated extensively. However, it is not known if irrigation solutions have any activity against established biofilm. This issue is pertinent as successful management of patients with periprosthetic joint infection (PJI) includes the ability to remove biofilm established on the surface of implants and necrotic tissues. The purpose of this study was to evaluate the efficacy of various irrigation solutions in eradicating established biofilm, as opposed to planktonic bacteria, in a validated in vitro model.

The purpose of this study was to determine whether the reasons for delay to surgery are secondary to health system constraints or patient factors. This study explored factors that contribute to patients' delay to surgery as well as how patients perceive the delay in surgery to have affected their treatment and care.

Semi-structured qualitative interviews were conducted with 30 patients aged 18 to 50 years old who had undergone arthroscopic ACL reconstruction. Qualitative data analysis was performed in accordance with the Straus and Corbin theory to derive codes, categories and themes.

Patient interviews revealed three overarching themes regarding delay to ACL reconstruction surgery: access to care, finances and work, and personal advocacy. Elements of those factors were shown to influence the timing of ACL reconstruction surgery. Less common factors included choice of imaging study (i.e., ultrasound), geography, and family commitments.

Patients' perceptions of delay in access to care was overwhelming due to the wait time for MRI. Several patients also described significant self-advocacy required to navigate the healthcare system, suggesting that some level of medical literacy may be necessary to gain timely access to surgery. Once patients had seen the surgeon, few patients described untimely delay to surgery, suggesting that OR resources are adequate. Recommendations to decrease delays to ACL reconstruction surgery include better access to MRI and broader education of non-surgical healthcare providers to help navigate access to surgery.

Previous biomechanical studies of lateral collateral ligament (LCL) injuries and their surgical repair, reconstruction and rehabilitation have primarily relied on gravity effects with the arm in the varus position. The application of torsional moments to the forearm manually in the laboratory is not reproducible, hence studies to date likely do not represent forces encountered clinically.

The aim of this investigation was to develop a new biomechanical testing model to quantify posterolateral stability of the elbow using an in vitro elbow motion simulator.

Six cadaveric upper extremities were mounted in an elbow motion simulator in the varus position. A threaded screw was then inserted on the dorsal aspect of the proximal ulna and a weight hanger was used to suspend 400g, 600g, and 800g of weight from the screw head to allow torsional moments to be applied to the ulna. An LCL injured (LCLI) model was created by sectioning of the common extensor origin, and the LCL. Ulnohumeral rotation was recorded using an electromagnetic tracking system during simulated active and passive elbow flexion with the forearm pronated and supinated. A repeated measures analysis of variance was performed to compare elbow states (intact, LCLI, and LCLI with 400g, 600g, and 800g of weight).

During active motion, there was a significant difference between different elbow states (P=.001 pronation, P=.0001 supination). Post hoc analysis showed that the addition of weights did not significantly increase the external rotation (ER) of the ulnohumeral articulation (10°±7°, P=.268 400g, 10.5°±7.1°, P=.156 600g, 11°±7.2°, P=.111 800g) compared to the LCLI state (8.4°±6.4°) with the forearm pronated. However, with the forearm supinated, the addition of 800g of weight significantly increased the ER (9.2°±5.9°, P=.038) compared to the LCLI state (5.9°±5.5°) and the addition of 400g and 600g of weights approached significance (8.2°±5.7°, P=.083 400g, 8.7°±5.9°, P=.054 600g).

During passive motion, there was a significant difference between different elbow states (P=.0001 pronation, P=.0001 supination). Post hoc analysis showed that the addition of 600g and 800g but not 400g resulted in a significant increase in ER of the ulnohumeral articulation (9.3°±7.8°, P=.103 400g, 11.2°±6.2°, P=.004 600g, 12.7°±6.8°, P=.006 800g) compared to the LCLI state (3.7°±5.4°) with the forearm pronated. With the forearm supinated, the addition of 400g, 600g, and 800g significantly increased the ER (11.7°±6.7°, P=.031 400g, 13.5°±6.8°, P=.019 600g, 14.9°±6.9°, P=.024 800g) compared to the LCLI state (4.3°±6.6°).

This investigation confirms a novel biomechanical testing model for studying PLRI. Moreover, it demonstrates that the application of even small amounts of torsional moment on the forearm with the arm in the varus position exacerbates the rotational instability seen with the LCL deficient elbow. The effect of torsional loading was significantly worse with the forearm supinated and during passive elbow motion. This new model allows for a more provocative testing of elbow stability after LCL repair or reconstruction. Furthermore, this model will allow for smaller sample sizes to be used while still demonstrating clinically significant differences. Future biomechanical studies evaluating LCL injuries and their repair and rehabilitation should consider using this testing protocol.

Introduction

Cobalt-Chromium-Molybdenum (CoCr) and Titanium-Aluminium-Vanadium (Ti) alloys are the most commonly used alloys used for Total Hip Replacement due to their excellent biocompatibility and mechanical properties. However, both are susceptible to fretting corrosion In-vivo. The objective of this study was to understand the damage mechanism of both combinations through a sub-surface damage assessment of the alloys at various fretting amplitudes using the Transmission Electron Microscopy (TEM – CM200 FEGTEM). The TEM was used to attain a cross sectional view of the alloys in orderto see the effect of high shear stress on the grain structure.

Introduction

Dislocation is one of severe complications after total hip arthroplasty (THA). Direct anterior approach (DAA) is useful for muscle preservation. Therefore, it might be also effective to reduce dislocation. The purpose of this study is to investigate the ratio and factors of dislocations after THA with DAA.

[Background]

Bipolar hemiarthroplasty (following BHA) have historically had poor results in patients with idiopathic osteonecrosis of femoral head (OFNH). However, most recent report have shown excellent results with new generation BHA designs that incorporate advances in bearing technology. These optimal outcomes with bipolar hemiarthroplasty will be more attractive procedure for young patients who need bone stock for future total arthroplasty. The purpose of the current study was to evaluate the clinical and radiographic finding of this procedure for the treatment of OFNH at our institution after 7-to 21years follow-up.

Introduction

The success of cementless total hip arthroplasty (THA) depends on the primary stability of the components. One of the biomechanical factors that comes into play is the mechanical quality of the bone. To our knowledge, there are no reported studies in the literature analyzing the impact of the preoperative bone mineral density on the outcomes of cementless THA. The goal of the study was to analyze the clinical results at 2 year follow-up according to the preoperative cancellous bone mineral density (BD). Our hypothesis was that the clinical outcomes were correlated to the BD.

Creating cement keyholes (i.e. drilling simple holes in cancellous bone to allow cement filling) is a practice used in multiple scenarios in orthopaedic surgery to ensure improved fixation between the bone-cement interface and as such between bone and prosthesis. It is most commonly used in hip arthroplasty to secure fixation of the cup to the acetabulum by drilling keyholes in acetabulum. However very little research has been conducted into what the dimensions of such cement keyholes should be. The following laboratory based research was performed to provide insight into the optimum dimensions of cement keyholes.

The investigator designed a novel arrangement to enable testing of keyholes. Beechwood block models were then made to this design testing keyholes of varying diameters and depths. These were cemented with acrylic bone cement and then loaded to failure. A finite system analysis was also performed.

Results show that stresses are concentrated at the base of the keyhole. As such increasing diameter of keyhole infers greater strength, but there is no relationship between depth and strength. This has been further confirmed with finite element analysis. We suggest the width of cement keyholes bears more importance than the depth and propose drilling wide but shallow keyholes.

Introduction

The ability to manufacture implants at the point-of-care has become a desire for clinicians wanting to provide efficient patient-specific treatment. While some hospitals have adopted extrusion-based 3D printing (fused filament fabrication; FFF) for creating non-implantable instruments with low-temperature plastics, recent innovations have allowed for the printing of high-temperature polymers such as polyetheretherketone (PEEK). Due to its low modulus of elasticity, high yield strength, and radiolucency, PEEK is an attractive biomaterial for implantable devices. Though concerns exist regarding PEEK for orthopaedic implants due to its bioinertness, the creation of porous networks has shown promising results for bone ingrowth.

In this study, we endeavor to manufacture porous PEEK constructs via clinically-used FFF. We assess the effect of porous geometry on cell response and hypothesize that porous PEEK will exhibit greater preosteoblast viability and activity compared to solid PEEK. The work represents an innovative approach to advancing point-of-care 3D printing, cementless fixation for total joint arthroplasty, and additional applications typically reserved for porous metal.

In addition to mechanical stresses, an inflammatory mediated association between obesity and knee osteoarthritis (OA) is increasingly being recognised. Adipokines, such as adiponectin and leptin, have been postulated as likely mediators. Clinical and epidemiological differences in OA by race have been reported. What contributes to these differences is not well understood. In this study, we examined the profile of adipokines in knee synovial fluid (SF) and the gene expression profile of the infra-patellar fat pad (IFP) by race among patients with end-stage knee OA scheduled for knee arthroplasty.

Age, sex, weight and height (used to derive body mass index (BMI)) and race (White, Asian and Black) were elicited through self-report questionnaire prior to surgery. SF and IFP samples were collected at the time of surgery. Adipokines (adiponectin and leptin) were examined in the SF using MAGPIX Multiplex platform. IFP was profiled using Human Adipogenesis PCRArray and genes of interest were further validated via quantitative relative RT-PCR using Student's t-test. Overall differences in adiponectin and leptin concentrations were tested across race. Linear regression modeling was used to investigate the association between adiponectin and leptin concentrations (outcomes) and race (predictor; referent group: White), adjusting for age, sex and BMI.

67 patients (18 White, 33 Asian, 16 Black) were included. Mean SF adiponectin concentration was greatest in Whites (1175.05 ng/mL), followed by Blacks (868.53 ng/mL) and Asians (702.23 ng/mL) (p=0.034). The mean SF leptin concentration was highest in Blacks (44.88 ng/mL), followed by Whites (29.86 ng/mL) and Asians (20.18 ng/mL) (p=0.021). Regression analysis showed Asians had significantly lower adiponectin concentrations compared to Whites (p<0.05). However, leptin concentrations did not differ significantly by race after adjusting for covariates. Testing of the IFP, using the Adipogenesis PCRArray, showed significant higher expression of LEP gene (leptin, p=0.03) in Asians (n=4) compared to Whites (n=4).

There appears to be important racial differences in the SF adiponectin profile among individuals with end-stage knee OA. Differential gene expression in the IFP across racial groups could be a potential contributory source for the noted SF variations. Further work to determine the source and function of adipokines in knee OA pathophysiology across racial groups is warranted.

This work examines the Upper limb (UL) blast-mediated traumatic amputation (TA) significance from recent operations in Afghanistan. It is hypothesized that the presence of an UL amputation at any level is an independent predictor of torso injury.

A joint theatre trauma registry search was performed to determine the number of British casualties with TA and their associated injuries.

UL TA accounted for 15.7% of all amputations; distributed: shoulder disarticulation 2.5%, trans-humeral 30%, elbow disarticulation 10%, trans-radial 20% and hand 37.5%. The presence of an UL amputation was more likely in dismounted casualties (P=0.015) and is a predictor of an increased number of total body regions injured and thoracic injuries (P 0.001 and P 0.026 respectively). An increased Injury Severity Score (ISS) was seen in patients with multiple amputations involving the UL (UL TA present ISS=30, no UL TA ISS=21; P=0.000) and the ISS was not significantly different whether mounted or dismounted (P=0.806).

The presence of an upper limb amputation at any level should insight in the receiving clinician a high index of suspicion of concomitant internal injury; especially thoracic injury. Therefore with regards to blast mediated TA the injury patterns observed reflect a primary and tertiary blast mechanism of injury.

Purpose

Investigating the effects of femoral stem length on hip and knee muscle strength.

With an increasing ageing population and a rise in the number of primary hip arthroplasty, peri-prosthetic fracture (PPF) reconstructive surgery is becoming more commonplace. The Swedish National Hip Registry reported that, in 2002, 5.1% of primary total hip replacements required revision due to PPF. Laboratory studies have indicated that age, bone quality and BMI all contribute to an increased risk of PPF. Osteolysis and aseptic loosening contribute to the formation of loosening zones as described by Gruen, with subsequent increased risk of fracture. The aim of the study was to identify significant risk factors for PPF in patients who have undergone primary total hip replacement (THR).

Logbooks of three Consultant hip surgeons were filtered for patients who had THR-PPF fixation subsequent to trauma. Risk factors evaluated included sex, age, bone density (Singhs index), loosening zones, Vancouver classification, prosthesis stem angle relative to the axis of the femur, and length of time from THR to fracture. A control group of uncomplicated primary THR patients was also scrutinised.

Forty-six PPF were identified representing 2.59% of THR workload. The male: female ratios in both groups were not significantly different (1:1.27 and 1:1.14 respectively). Average age of PPF was 72.1, which was significantly older than the control group (54.7, p>0.05). The commonest type of PPF was Vancouver type B. Whilst stem position in the AP plane was similar in both groups, in lateral views the PPF stem angle demonstrated significant antero-grade leg position compared to the non-PPF group (p.0.05). The PPF group demonstrated a greater number of loosening zones in pre-fracture radiographs compared to the control group (2.59 and 1.39 respectively, p>0.05)

Our workload from PPF reflects that seen in Europe. Age, stem position and the degree of stem loosening appear to contribute to the risk of a peri-prosthetic fracture.

Purpose

Change of the pelvic tilt is an important factor affecting walking after total hip arthroplasty (THA). There are many reports of static evaluation of pelvic tilt by X-ray, however, there are few reports of dynamic evaluation during walking. In this study, we investigated change of pelvic tilt of THA subjects before and after operation during walking using an optical position sensor.

Malorientation of the acetabular cup in Total Hip replacement (THR) may contribute to premature failure of the joint through instability (impingement, subluxation or dislocation), runaway wear in metal-metal bearings when the edge of the contact patch encroaches on the edge of the bearing surface, squeaking of ceramic-ceramic bearings and excess wear of polyethylene bearing surfaces leading to osteolysis.

However as component malorientation often only occurs in functional positions it has been difficult to demonstrate and often is unremarkable on standard (usually supine) pelvic radiographs. The effects of spinal pathology as well as hip pathology can cause large rotations of the pelvis in the sagittal plane, again usually not recognized on standard pelvic views. While Posterior pelvic rotation with sitting increases the functional arc of the hip and is protective of a THR in regards to both edge loading and risk of dislocation, conversely Anterior rotation with sitting is potentially hazardous.

We developed a protocol using three functional positions – standing, supine and flexed seated (posture at “seat-off” from a standard chair). Lateral radiographs were used to define the pelvic tilt in the standing and flexed seated positions. Pelvic tilt was defined as the angle between a vertical reference line and the anterior pelvic plane. Supine pelvic tilt was measured from computed tomography.

Proprietary software (Optimized Ortho, Sydney) based on Rigid Body Dynamics then modelled the patients’ dynamics through their functional range producing a patient-specific simulation which also calculates the magnitude and direction of the dynamic force at the hip and traces the contact area between prosthetic head/liner onto a polar plot of the articulating surface. Given prosthesis specific information edge-loading can then be predicted based on the measured distance of the edge of the contact patch to the edge of the acetabular bearing.

Introduction

Acetabular cup orientation has been shown to be a factor in edge-loading of a ceramic-on-ceramic THR bearing. Currently all recommended guidelines for cup orientation are defined from static measurements with the patient positioned supine. The objectives of this study are to investigate functional cup orientation and the incidence of edge-loading in ceramic hips using commercially available, dynamic musculoskeletal modelling software that simulates each patient performing activities associated with edge-loading.

Purpose

Full-thickness tendon tears of the supraspinatus (SP) are common and can have a significant impact on shoulder function. To optimally treat supraspinatus tendon tears an accurate understanding of its musculotendinous architecture is needed. We have previously shown that the architecture of supraspinatus is complex. It has architecturally distinct regions: anterior and posterior, each of which is further subdivided into superficial, middle and deep parts (Kim et al., 2007). Data of FBL and PA of the torn supraspinatus could enhance clinical decision making and guide rehabilitative treatments (Ward et al., 2006). Currently, however, in vivo US quantification of the fiber bundle architecture of the distinct regions of supraspinatus in subjects with full-thickness tendon tears has not been investigated.

PURPOSE: To quantify architectural parameters within the distinct regions of supraspinatus in subjects with a full-thickness tendon tear using the US protocol that we previously developed (Kim et al., 2010), and to compare findings with age and gender matched normal controls.