Background

An improved understanding of intervertebral disc (IVD) structure and function is required for treatment development. Loading induces micro-fractures at the interface between the nucleus pulposus (NP) and the annulus fibrosus (AF), which is hypothesized to induce a cascade of cellular changes leading to degeneration. However, there is limited understanding of the structural relationship between the NP and AF at this interface and particularly response to load. Here, X-ray scattering is utilised to provide hierarchical morphometric information of collagen structure across the IVD, especially the interface region under load.

Accurate placement of the acetabular component is essential in Total Hip Arthroplasty (THA). The purpose of this study is to determine if an analog spirit level can improve the surgeon's ability to achieve acetabular inclination within the “safe-zone” of 30 to 50 degrees.

We reviewed 167 primary THAs performed by a single surgeon over 14 months. Procedures were performed at two facilities, an inpatient hospital where a spirit level was utilized and an ambulatory facility where it was not. We excluded 47 patients with a BMI>40, age>68 or a surgical indication other than osteoarthritis who were not candidates for the ambulatory center. Cup inclination angles were measured from de-identified plain radiographs by two blinded investigators not involved in the index procedures. The effect of level usage on inclination angle was determined using multivariate regression analysis.

The mean inclination angle for the 68 hips performed with the level was 42.9 degrees (95% CI: 41.7–44.0) compared to 46.5 degrees (95% CI: 45.2–47.7) for the 52 hips without it (p<.001). Regression analysis demonstrated a 9.1% difference in cup inclination due to the level (p<.001), and THAs performed without the level were 3 times more likely to result in inclinations > 50 degrees (OR 2.8, p=.036). The two investigators' measurements demonstrated a correlation of 0.95 (95% CI: 0.93–0.97).

Use of a simple spirit level resulted in a significant reduction in the number of outliers compared to the freehand technique. The spirit level may be a simple and inexpensive tool to improve acetabular component abduction angles.

Introduction

A common phenomenon occurring as a result of reverse total shoulder arthroplasties (RSA) is scapular notching. While bone loss of the scapula may be quantified using radiographic techniques,[1] the material loss on the humeral bearing has not been quantified. Depending on their functional biological activity, a high volume of polyethylene wear particles has been shown to be related to osteolysis, bone loss and ultimately, loosening of implants in other joints.[2] In order to understand the threshold for osteolysis in the shoulder, it is important to have a method that can accurately quantify the amount of material loss. The aim of this research was to (I) create and validate a method for quantifying material loss from a single humeral implant design which can then (II) be used to measure retrieved devices.

Introduction: Forearm fractures are the most common long bone fracture in the paediatric population. Associated neurological injury is a well recognized complication of these injuries yet is generally considered to beuncommon. This study sought to evaluate the incidence of neurological impairment in children referred for manipulation by the orthopaedics team in this tertiary referral hospital.

Materials & Methods: A retrospective chart analysis was performed of the first 100 children to be referred for orthopaedic assessment. This represented 43% of the total number of children presenting to the emergency department in this time period. Inclusion criteria involved a fracture of any segment of the radius and/or ulna on radiological examination. Exclusion criteria included concomitant ipsilateral upper limb fracture, and compartment syndrome.

Results: A total of 96 cases met the inclusion criteria. The cohort had a mean age of 8.04. Males were more likely to be injured as was the left forearm. The distal metaphysis was the segment most likely to be fractured and compound injuries were uncommon. The incidence of associated neurological impairment was 15.6%. The median nerve was most commonly injured, comprising 60% of nerve injuries. Distal physeal fractures were the most common fracture pattern to be associated with neurological impairment, with a rate of 37%.

Conclusions: Forearm fractures requiring manipulation in the paediatric population are commonly associated with nerve injuries, with distal physeal fractures having a particularly strong correlation. Clinicians require a high index of suspicion for nerve injury when evaluating forearm fractures to avoid underdiagnosis. Failure to recognize neurological injury at the time of initial assessment has the potential to delay time to reduction due to the injury being misclassified as non-urgent. This delay has the potential to cause a prolonged or failed recovery of nerve function.

Introduction: Systematic reviews have found that sitting at work is not associated with LBP, although the biomechanical evidence does offer plausible causative mechanisms. Indeed, exposure to lumbar postures has been assessed using imprecise tools that have limited epidemiological investigations. The aim of this study was to use new technology to measure the seated lumbar postures of sedentary (call centre) workers, and survey their current and future symptoms in order to determine associations with LBP.

Methods: A fibre-optic goniometer (FOG) system was attached to the lumbar spine and hip of 181 sedentary call centre workers at the start of their working shift. The lumbar FOG provides a continuous measure of sagittal lumbar curvature (lumbar position and movement), whilst the hip FOG enables quantification of sitting time. Baseline and 6-month follow-up questionnaires were used to collected symptom data, and logistic regression was used to determine associations between postural and symptom (yes/no) data.

Results: Workers spent a mean proportion of 83% of work-time sitting, with 17% sitting for more than 90 minutes without a break. Current LBP (symptoms lasting more than 24hrs) was associated with a kyphotic (mean lumbar angle> 180°) sitting posture (yes/no) (OR 2.1, 1.1–4.1), although movement (mean standard deviation and angular velocity °sec-1) in sitting was not. Sitting relatively static (AV< 4.26° yes/no) (OR 3.30, 1.06–10.25), using a small amount of range (SD< 10.2° yes/no) (OR 3.79, 1.2–11.7), and adopting a kyphotic posture (yes/no) (OR 2.75, 1.02–7.3) all significantly increased the risk of future LBP.

Discussion: Sitting postures at work are associated with current LBP and are statistically significant risks for recurrence. These results highlight the potential for ergonomic interventions to reduce current symptoms and the risk of future episodes. The findings from this study are novel, and the FOG system should now be used in larger investigations of sedentary risk factors for LBP.

Background: Many sedentary workers will experience low back pain (LBP) whilst sitting, and some will believe that work caused their symptoms. They also report that their symptoms can be aggravated or relieved by work. Little is known about sedentary workers’ beliefs about the causes of back pain or symptom modifying factors (SMFs), and this study sought to determine their influence on absence.

Methods: 600 call centre workers completed validated questionnaires concerning beliefs about work-related causes of LBP in sedentary work and SMFs. Three constructs for work-related causes of LBP (physical demands; work environment; work organisation), and three groups of SMFs (physical aggravating; movement relieving; and postural relieving factors) were measured. A 6-month follow-up survey identified workers who did and did not take absence due to LBP. Logistic regression was used to predict future absence.

Results: Results indicated that, on their own, beliefs about the work environment (OR 1.2, 95% CI 1.1–1.4), and work organisation (OR 1.2, 95% CI 1.0–1.3) were significant risks for future absence (P< 0.001). Physical aggravating factors also represented a significant risk (OR 1.3, 95% CI 1.1–1.4, P< 0.001). Perceived physical demands and relieving factors were not significant (P> 0.05). The multivariable model showed that physical aggravating factors accounted for 16% of the variance (OR 1.3, 95% CI 1.1–1.4).

Conclusions: Beliefs about the work environment/organisation and physical aggravating factors are significant risks for future absence, although when considered together, physical aggravating factors dominate. These results highlight the potential for ergonomic interventions to reduce symptom-aggravating aspects of work to reduce absence.

Background: Sickness absence, care seeking and symptoms lasting more than 24 hours have all been used to quantify an episode of low back pain (LBP). These measures do not take into account the transient and fluctuating symptoms that sedentary workers may experience over the course of the day, or from day to day. Some workers may not even describe their symptoms as ‘painful’, perhaps preferring alternative pain adjectives such as ‘discomfort’ or ‘aching’. The importance of these symptoms when sitting at work in relation to the development of persistent symptoms and work loss is unknown.

Methods: A new low back discomfort scale was developed based on a 100mm VAS scale ranging from 0 (no discomfort), through to 100 (severe discomfort). Subjects (n=41) were asked to mark on the scale the intensity of any discomfort, i.e. ache, strain, unpleasant sensation or pain experienced when sitting at work in the past week. Subjects were re-tested after a two week time-lapse, and paired t-tests were used to determine test-retest stability.

Results: The retest response rate was 46%, and there were no statistically significant differences (p > 0.05) between test (28mm), and retest (21mm) mean scores. Reports from subjects suggest that the scale has face validity.

Conclusions: The low back discomfort scale was shown to be valid and reliable, providing a broad measure of reported symptom intensity when sitting at work. This scale will now be used in sedentary work environments alongside biomechanical and psychosocial measures to investigate risk factors for persistent LBP and sickness absence.

Background: Symptom modifying factors (SMFs) are everyday activities or postures that are reported to aggravate or alleviate existing LBP symptoms. In relation to sedentary jobs, workers are known to experience LBP whilst sat at work, and may report that aspects of sitting either aggravate or alleviate their symptoms. These factors appear to have received little attention in the literature, and may help to discriminate workers with different types of LBP, or identify workers likely to take sickness absence due to LBP.

Methods: A new sitting and symptom modifying factors questionnaire (SSMQ) was designed and consisted of 11 items. This questionnaire was distributed to 135 sedentary workers on two occasions with a 2 week time lapse. Principal components analysis (PCA) and Cronbach’s alpha were used to explore the structure and internal consistency of the questionnaire. Paired t-tests were used to determine test-retest stability.

Results: Three factors with eigenvalues > 1 were extracted that explained 62% of the total variance, and each factors items loaded > 0.06. These sub-scales related to aggravating and relieving (movement and posture) factors, and had consistency levels of 0.80, 0.72 and 0.78 respectively. The retest response rate was 46% and there were no statistically significant differences (p > 0.05) between test-retest measures.

Conclusions: Validating the SSMQ has produced an instrument that can be used in sedentary jobs to investigate the influence of symptom modifying factors on LBP symptoms, care seeking and sickness absence due to LBP. This questionnaire will now be used in a prospective study of sedentary call centre workers.

Aims: Acute lateral dislocation of the patella has been associated with disruption of the medial restraints of the patella and following non-operative management, a redislocation rate of up to 44%. Methods: Ten patients who presented to the Accident and Emergency dept. following acute patella dislocation had an ultrasound scan (USS) performed by an experienced musculoskel-etal radiologist. Each patient had an arthroscopy and washout of the knee and repair of ruptured structures. The ultrasound reports have now been compared to the surgical findings to determine the effectiveness of this investigation. Results: The ultrasound scans identified deficiencies in the ligamentous attachments to the medial border of the patella in eight patients and these were confirmed at operation in the same eight. The USS diagnosis of haematoma or torn fibres in the vastus medialis obliquus (VMO) (5 patients) corresponded with tearing of this muscle at operation; however the degree of muscle injury was underestimated in two. The USS finding of free fluid around the medial collateral ligament (MCL) at the adductor tubercle in three patients was associated with the operative finding of disruption of the femoral origin of the medial patellofemoral ligament (MPFL). Haematomata detected on USS along the adductor longus in two patients proved to have disruption of the VMO attachment. Conclusions: We recommend the use of ultrasound for assessment of all patella dislocations to accurately locate tears of the retinaculum and help clinicians to understand the severity of injury to the soft tissue restraints of the patella.

Acute lateral dislocation of the patella has been associated with disruption of the medial restraints of the patella. Following non-operative management there is a redislocation rate of up to 44%. This is an observational study testing whether sonography is a reliable method of assessing the medial retinaculum after acute dislocation of the patella.

Ten patients following acute patellar dislocation had an ultrasound scan (USS) performed by an experienced musculoskeletal radiologist. Each patient subsequently had an examination under anaesthetic, arthroscopy, and repair of the ruptured structures. The ultrasound reports were compared to the surgical findings to determine the accuracy of this investigation.

USS located deficiencies in the ligamentous attachments to the medial border of the patella and the presence of avulsed bony fragments, all of which were confirmed at operation. The sonographic diagnosis of haematoma or torn fibres in the vastus medialis obliquus corresponded with our operative findings.

The most significant findings were the correlation of free fluid around the medial collateral ligament (MCL) with avulsion of the femoral attachment of the medial patellofemoral ligament (MPFL) and the presence of avulsed fragments of bone from the medial border of the patella.

Sonography, in cadaveric studies consistently identifies the retinacula and like MRI offers a distinctive constellation of findings that can be used in diagnosis and therefore play a significant role in directing surgical management of these patients. We have found Sonography to be readily available and accurate.

This report does not include surgical outcome since the follow up is short and incomplete. We do, however, feel that ultrasound shows the state of the soft tissue restraints of the patella following lateral dislocation.