Introduction

Flexor sheath infections require prompt diagnosis, and management with intravenous antibiotics and/or surgical washout followed by physiotherapy. Complication rates as high as 38% have been reported.

The purpose of this study was to determine long-term survival free from all-cause revision and stem-related failure, as well as radiographic and functional outcomes of the ZMR stem in revision THA.

We retrospectively identified all patients in our institutional database who underwent revision THA using the ZMR Revision Hip system from the year 2000 to 2007 (minimum two-year follow-up). Of the 112 ZMR hips (110 patients) identified, a total of 106 hips (104 patients) met inclusion criteria. The mean study follow-up 13.9 years (range 2–22). Indications for index ZMR revision included aseptic loosening (72.1%), periprosthetic joint infection (17.3%), periprosthetic fracture (9.6%), and stem fracture (1.0%). Kaplan-Meier analysis was used to determine the all-cause and stem-related failure revision-free survival. Validated patient reported outcomes were collected and available radiographs were reviewed to determine implant stability.

A total of 17 hips (16.0%) underwent a re-revision of any component. The indications for re-revision were stem failure (35.3%), infection (29.4%), instability (29.4%), and aseptic loosening of the acetabular component (5.9%). The five- and 15-year all-cause survivorship was 89.5% (95% CI 86.5–92.5) and 83.0% (95% CI 79.2–86.8), respectively. There were six re-revisions for stem failure (5.7%); five for stem fracture and one for aseptic loosening. The average time to stem failure was 4.6 years (range 1.3–8.2). The five- and 15-year survivorship free from stem-related failure was 97.2% (95% CI 95.6–98.8) and 93.9% (95% CI 91.5–96.3), respectively. At final follow-up the mean Oxford hip score was 36.9 and all surviving ZMR stems were well fixed on radiographs.

Femoral revision with the ZMR stem offers satisfactory long-term survivorship and promising clinical outcomes. Although uncommon, stem fracture was the most common reason for stem-related failure.

Aims

The aim of this study was to describe services available to patients with periprosthetic femoral fracture (PPFF) in England and Wales, with focus on variation between centres and areas for care improvement.

Aims

Hip resurfacing remains a potentially valuable surgical procedure for appropriately-selected patients with optimised implant choices. However, concern regarding high early failure rates continues to undermine confidence in use. A large contributor to failure is adverse local tissue reactions around metal-on-metal (MoM) bearing surfaces. Such phenomena have been well-explored around MoM total hip arthroplasties, but comparable data in equivalent hip resurfacing procedures is lacking. In order to define genetic predisposition, we performed a case-control study investigating the role of human leucocyte antigen (HLA) genotype in the development of pseudotumours around MoM hip resurfacings.

A hip fracture represents the extreme end of osteoporosis, placing a significant burden on secondary care, society, and the individual patient. The National Hip Fracture Database (NHFD) reports each hospital's attainment of the BPT with other measures, along with reporting outcomes. There is clearly wide variability in provision of orthogerriatrician (OG) services across the dataset. Unfortunately, despite overwhelming evidence that provision of an OG service is of benefit, it is presently challenging to recruit to this important specialty within the UK.

Publicly available reports from the NHFD were obtained for each of the 177 participating hospitals for 2017. This was matched with information held within the annual NHFD Facilities Audit for the same period, which include hours of OG support for each hospital. This information was combined with a Freedom of Information request made by email to each hospital for further details concerning OG support. The outcome measures used were Length of Stay (LoS), mortality, and return to usual residence. Comparison was made with provision of OG services by use of Pearson's correlation coefficient. In addition, differences in services were compared between the 25% (44) hospitals delivering outcomes at the extremes for each measure.

Attainment of BPT correlated fairly with LoS (−0.48) and to less of a degree with mortality (−0.1) and return home (0.05). Perioperative medical assessment contributed very strongly with BPT attainment (0.75). In turn perioperative medical assessment correlated fairly with LoS (−0.40) and mortality (−0.23) but not return home (0.02). Provision of perioperative medical assessment attainment was correlated fairly with total OG minutes available per new patient (0.22), total OG minutes available per patient per day (0.29) and number of days per week of OG cover (0.34); with no link for number of patients per orthogeriatrician (0.01). Mortality for the best units were associated with 30% more consultant OG time available per patient per day, and 51% more OG time available per patient. Units returning the most patients to their usual residence had little association with OG time, although had 59% fewer patients per OG, the best units had a 19% longer LoS. For all three measures results for the best had on average 0.5 days per week better routine OG access.

There is no doubt that good quality care gives better results for this challenging group of patients. However, the interaction of BPT, other care metrics, level of OG support and patient factors with outcomes is complex. We have found OG time available per patient per day appears to influence particularly LoS and mortality. Options to increase OG time per patient include reducing patient numbers (ensuring community osteoporosis/falls prevention in place, including reducing in-patient falls); increasing OG time across the week (employing greater numbers/spreading availability over 7 days per week); and reducing LoS. A reduction in LoS has the largest effect of increasing OG time, and although it is dependent on OG support, it is only fairly correlated with this and many other factors play a part, which could be addressed in units under pressure.

Aims

Within healthcare, several measures are used to quantify and compare the severity of health conditions. Two common measures are disability weight (DW), a context-independent value representing severity of a health state, and utility weight (UW), a context-dependent measure of health-related quality of life. Neither of these measures have previously been determined for developmental dysplasia of the hip (DDH). The aim of this study is to determine the DW and country-specific UWs for DDH.

Aims

Despite multiple trials and case series on hip hemiarthroplasty designs, guidance is still lacking on which implant to use. One particularly deficient area is long-term outcomes. We present over 1,000 consecutive cemented Thompson’s hemiarthroplasties over a ten-year period, recording all accessible patient and implant outcomes.

Aims

Orthopaedic surgeries are complex, frequently performed procedures associated with significant haemorrhage and perioperative blood transfusion. Given refinements in surgical techniques and changes to transfusion practices, we aim to describe contemporary transfusion practices in orthopaedic surgery in order to inform perioperative planning and blood banking requirements.

Aims

The purpose of our study was to determine which groups of orthopaedic providers favour virtual care, and analyze overall orthopaedic provider perceptions of virtual care. We hypothesize that providers with less clinical experience will favour virtual care, and that orthopaedic providers overall will show increased preference for virtual care during the COVID-19 pandemic and decreased preference during non-pandemic circumstances.

Understanding the long-term effects of total knee arthroplasty (TKA) on joint kinematics is vital to assess the success of the implant design and surgical procedure. However, while in vitro cadaveric studies quantifying post-operative biomechanics primarily reflect joint behaviour immediately after surgery,¹in vivo studies comprising of follow-up TKA patients often reflect joint behaviour a few months after surgery.² Therefore, the aim of this cadaveric study was to explore the long-term effects of TKA on tibiofemoral kinematics of a donor specimen, who had already undergone bilateral TKA, and compare them to post-operative kinematics reported in the literature.

Two fresh-frozen lower limbs from a single donor (male, age: 83yr, ht: 1.83m, wt: 86kg), who had undergone bilateral TKA (Genesis II, Smith&Nephew, Memphis, USA) 19 years prior to his demise, were obtained following ethical approval from the KU Leuven institutional board. The specimens were imaged using computed tomography (CT) and tested in a validated knee simulator³ replicating active squatting and varus-valgus laxity tests. Tibiofemoral kinematics were recorded using an optical motion capture system and compared to various studies in the literature using the same implant – experimental studies based on cadaveric specimens (CAD)^1,4 and an artificial specimen (ART)⁵, and a computational study (COM)⁶.

Maximum tibial abduction during laxity tests for the left leg (3.54°) was comparable to CAD (3.30°), while the right leg exhibited much larger joint laxity (8.52°). Both specimens exhibited valgus throughout squatting (left=2.03±0.57°, right=5.81±0.19°), with the change in tibial abduction over the range of flexion (left=1.89°, right=0.64°) comparable to literature (CAD=1.28°, COM=2.43°). The left leg was externally rotated (8.00±0.69°), while the right leg internally rotated (−15.35±1.50°), throughout squatting, with the change in tibial rotation over the range of flexion (left=2.61°, right=4.79°) comparable to literature (CAD=5.52°, COM=4.15°). Change in the femoral anteroposterior translation over the range of flexion during squatting for both specimens (left=14.88mm, right=6.76mm) was also comparable to literature (ART=13.40mm, COM=20.20mm).

Although TKA was reportedly performed at the same time on both legs of the donor by the same surgeon, there was a stark difference in their post-operative joint kinematics. A larger extent of intraoperative collateral ligament release could be one of the potential reasons for higher post-operative joint laxity in the right leg. Relative changes in post-operative tibiofemoral kinematics over the range of squatting were similar to those reported in the literature. However, differences between absolute magnitudes of joint kinematics obtained in this study and findings from the literature could be attributed to different surgeons performing TKA, with presumable variations in alignment techniques and/or patient specific instrumentation, and the slightly dissimilar ranges of knee flexion during squatting.

In conclusion, long-term kinematic effects of TKA quantified using in vitro testing were largely similar to the immediate post-operative kinematics reported in the literature; however, variation in the behaviour of two legs from the same donor suggested that intraoperative surgical alterations might have a greater effect on joint kinematics over time.

Orthopaedic training sessions, vital for surgeons to understand post-operative joint function, are primarily based on passive and subjective joint assessment. However, cadaveric knee simulators, commonly used in orthopaedic research,¹ could potentially benefit surgical training by providing quantitative joint assessment for active functional motions. The integration of cadaveric simulators in orthopaedic training was explored with recipients of the European Knee Society Arthroplasty Travelling Fellowship visiting our institution in 2018 and 2019. The aim of the study was to introduce the fellows to the knee joint simulator to quantify the surgeon-specific impact of total knee arthroplasty (TKA) on the dynamic joint behaviour, thereby identifying potential correlations between surgical competence and post-operative biomechanical parameters.

Eight fellows were assigned a fresh-frozen lower limb each to plan and perform posterior-stabilised TKA using MRI-based patient-specific instrumentation. Surgical competence was adjudged using the Objective Structured Assessment of Technical Skills (OSATS) adapted for TKA.² All fellows participated in the in vitro specimen testing on a validated knee simulator,³ which included motor tasks – passive flexion (0°-120°) and active squatting (35°-100°) – and varus-valgus laxity tests, in both the native and post-operative conditions. Tibiofemoral kinematics were recorded with an optical motion capture system and compared between native and post-operative conditions using a linear mixed model (p<0.05). The Pearson correlation test was used to assess the relationship between the OSATS scores for each surgeon and post-operative joint kinematics of the corresponding specimen (p<0.05).

OSATS scores ranged from 79.6% to 100% (mean=93.1, SD=7.7). A negative correlation was observed between surgical competence and change in post-operative tibial kinematics over the entire range of motion during passive flexion – OSATS score vs. change in tibial abduction (r=−0.87; p=0.003), OSATS score vs. change in tibial rotation (r=−0.76; p=0.02). When compared to the native condition, post-operative tibial internal rotation was higher during passive flexion (p<0.05), but lower during squatting (p<0.033). Post-operative joint stiffness was greater in extension than in flexion, without any correlation with surgical competence.

Although trained at different institutions, all fellows followed certain standard intraoperative guidelines during TKA, such as achieving neutral tibial abduction and avoiding internal tibial rotation,⁴ albeit at a static knee flexion angle. However, post-operative joint kinematics for dynamic motions revealed a strong correlation with surgical competence, i.e. kinematic variability over the range of passive flexion post-TKA was lower for more skilful surgeons. Moreover, actively loaded motions exhibited stark differences in post-operative kinematics as compared to those observed in passive motions. In vitro testing on the knee simulator also introduced the fellows to new quantitative parameters for post-operative joint assessment.

In conclusion, the inclusion of cadaveric simulators replicating functional joint motions could help quantify training paradigms, thereby enhancing traditional orthopaedic training, as was also the unanimous opinion of all participating fellows in their positive feedback.

Introduction

THA for patient's 50 years and younger is a procedure at high risk for complications and failure because of the high level of activity of this population. Highly cross linked polyethylene (HXLPE) has greatly improved the durability of the implant because of the improved wear characteristics. Few studies have followed this population into the second decade and therefore the purpose of this investigation was to evaluate the clinical outcome for the patients 5o years of age and younger at a minimum of 15 years. The second purpose was to evaluate the radiographic findings secondary to wear or mechanical failure of the implant.

Introduction

Our objective is to describe early and midterm results with the use of a new knee prosthesis as an articulating spacer in planned two-stage management for infected total knee arthroplasty. As a second objective, we compared outcomes between the group with a retained first stage and those with a completed 2-stage revision.

Introduction

Spinopelvic mobility has been associated with THA outcome. To-date spine assessments have been made quasi-statically, using radiographs, in standing and seated positions but dynamic spinopelvic mobility has not been well explored. This study aims to determine the association between dynamic (motion analysis) and quasi-static (radiographic) sagittal assessments and examine the association between axial and sagittal spinal kinematics in hip OA patients and controls.

Aims

Extracellular matrix (ECM) and its architecture have a vital role in articular cartilage (AC) structure and function. We hypothesized that a multi-layered chitosan-gelatin (CG) scaffold that resembles ECM, as well as native collagen architecture of AC, will achieve superior chondrogenesis and AC regeneration. We also compared its in vitro and in vivo outcomes with randomly aligned CG scaffold.

Aims

Our rural orthopaedic service has undergone service restructure during the COVID-19 pandemic in order to sustain hip fracture care. All adult trauma care has been centralised to the Royal Shrewsbury Hospital for assessment and medical input, before transferring those requiring operative intervention to the Robert Jones and Agnes Hunt Orthopaedic Hospital. We aim to review the impact of COVID-19 on hip fracture workload and service changes upon management of hip fractures.

Acromioclavicular joint is an integral component of Shoulder Complex and common site of injury particularly for athletes involved in sports such as Football, Cricket, Rugby and Shotput. Acromioclavicular Injuries are often neglected and goes untreated especially in low demand patients. Classic surgical techniques are associated with high complication rates.

This is a prospective study from 2015–2017 wherein 32 patients with Acute grade 3, 4, 5, 6 Acromioclavicular joint dislocations, were operated with Minimally Invasive Double Tunnel Anatomical Coraco-clavicular Ligament Reconstruction (DT-ACCLR) with Tightrope Suspensory fixation. Clinical Outcomes were evaluated with Visual Analog Scale, Constant functional scale, Start of Movement, Return to Work, Satisfaction index and Coraco-clavicular distance over 12 months.

Mean follow-up was 14 ± 3.8 months. Visual analog scale and Constant scores revealed significant advancements 0 ± 0.5 (range, 0–2) and 95 ± 3 (range, 92–98) scores at 12 months respectively. The coraco-clavicular distance significantly reduced from 23 ± 2.4 mm to 8 ± 0.5 mm. Mean return to work by 7 days. 98.6% patients were satisfied with surgical results.

We conclude that DT-ACCLR is simple and creative surgical technique which provides stable, reliable and painless AC joint. The patients can move the shoulder same day and return to Work by 5–7days and Sports 3–4 weeks.

Osteochondroplasty procedure for cam deformity provides excellent outcomes on alleviating pain, improving quality of life and clinical function in femoroacetabular impingement syndrome (FAIS) patients. Although medium-term outcomes on gait biomechanics have been reported, it is unclear how it would translate to better hip muscle forces and joint loading in high range of motion tasks. The purpose of this study was to compare the muscle forces and hip joint contact forces (HCF) during a squat task in individuals before and after cam-FAIS surgical correction. Ten cam-FAIS patients prior and 2-years after osteochondroplasty, and 10 BMI- age- and sex-matched healthy control participants (CTRL) underwent 3D motion and ground reaction forces capture while performing a deep squatting task. Muscle and HCF were estimated using musculoskeletal modeling and comparisons were done using statistical parametric mapping (SPM).

Postoperatives squatted down with a higher anterior pelvic tilt and higher hip flexion compared with the preoperatives. Preoperative semimembranosus generated lower forces than the two other groups on the squat ascending, with no differences detected between post-ops and CTRLs. Preoperatives also showed reduced forces for the distal, ischial and medial portions of the adductor magnus relative to the CTRLs, which although reduced, still presented differences postoperatively. Preoperative anterior and medial contact forces were significantly lower than the CTRL group during both phases of the squat. Postoperative vertical and medial forces were also lower compared to the CTRLs. However, with higher vertical forces during the ascent phase of the squat compared to the preoperative, the postoperative group, significantly increased its HCF magnitude. A higher anterior pelvic tilt was associated with an innate restoration of the pelvis position, once the cam deformity no longer existed. The increased force of the semimembranosus muscle while ascending the squat generated higher vertical HCF, which also influenced the increased HCF total magnitude.

For any tables or figures, please contact the authors directly.

Introduction

The number of medial unicompartmental knee replacements (UKR) performed for arthritis has increased and as such, revisions to total knee replacement (TKR) is increasing. Previous studies have investigated survivorship of UKR to TKR revision and functional outcomes compared to TKR to TKR revision, but have failed to detail the surgical considerations involved in these revisions. Our objectives are to investigate the detailed surgical considerations involved in UKR to TKR revisions.

Introduction

The practice of overlapping surgery has been increasing in the delivery of orthopaedic care, aiming to provide efficient, high-quality care. However, there have been concerns about the safety of this practice. The purpose of this study is to examine safety and efficacy of a model of partially overlapping surgery that we termed “the swing room” in practice in primary hip and knee arthroplasty.

Introduction

Meaningful clinical improvement as demonstrated through patient-reported outcome measures (PROMs) are increasingly used to evaluate success of total hip arthroplasty (THA) procedures. This patient perspective can provide a full picture when used with clinical data to best evaluate surgical outcomes.

Background

Fully constrained liners are used to treat recurrent dislocations or patients at high risk after total hip replacements. However, they can cause significant morbidities including recurrent dislocations, infections, aseptic loosening and fractures. We examine long term results of 111 patients with tripolar constrained components to assess their redislocation and failure rate.

Background

High complication rates and poor outcomes have been widely reported in patients undergoing revision of large head metal-on-metal arthroplasty. A previous study from our center showed high rates of dislocation, nerve injury, early cup loosening and pseudotumor recurrence. After noting these issues, we implemented the following changes in surgical protocol in all large head MOM revisions: 1. Use of highly porous shells in all cases 2. Use of largest femoral head possible 3. Low threshold for use of dual mobility and constrained liners when abductors affected or absent posterior capsule 4. Use of ceramic head with titanium sleeve in all cases 5. Partial resection of pseudotumor adjacent to sciatic and femoral nerves.

Introduction

Patients under the age of 50 who undergo a total hip arthroplasty (THA) are at high risk for wear-related complications due to their higher activity level. Previous studies have shown that highly crosslinked polyethylene (HXLPE) is more durable with no evidence of loosening compared to conventional polyethylene due to its improved wear characteristics. Unfortunately, there are few studies with long term follow-up of HXLPE in this patient population. The purpose of this study was to evaluate two questions related to this population of patients undergoing THA. First, what were the clinical outcomes for HXLPE in patients 50 years or younger at an average follow-up of 15 years? Second, was osteolysis observed in any of these hips?

Background

Pseudotumor or high grade ALVAL (aseptic lymphocyte-dominated vasculitis-associated lesion) development around total hip replacements secondary to local metal debris generation – especially in the setting of metal-on-metal bearings – is a well-recognised histopathologic phenomenon. Recent work has suggested a strong genetic correlation with an individual's risk of such lesion development following metal exposure. Emerging data have highlighted a similar potential concern around total knee replacements (TKRs), particularly with increasing construct modularity. To date, the body-of-knowledge pertaining to TKR-associated ALVALs has largely been limited to individual case reports or small retrospective case series’, with no large-scale investigation looking at this potential complication. This study sought to establish the preliminary prevalence of pseudotumor or high grade ALVAL formation seen at the revision of primary TKRs and to establish the correlation between histologic ALVAL grade and patient-reported functional outcomes.

Gap balancing technique aims to achieve equal and symmetric gap at full extension and in flexion; however, little is known about the connection between the native and the replaced knee gaps. In this study, a novel robotic assisted ligament tensioning tool was used to measure the pre- and post- operative gaps to better understand their relationship when aiming for balance gaps in flexion and extension. The accuracy of a prediction algorithm for the post-operative gaps based on the native gap and implant alignment was evaluated in this study. The medial and lateral gap were smallest at full extension. The native gaps increase with flexion until 30 degrees where they plateaued for the remaining flexion range. The native lateral gap was larger than the medial gap throughout the flexion range. Planning for equal gaps at extension and flexion resulted with tightest gaps at these angle; however, the gaps in mid-flexion were 3–4 mm larger. Good agreement was observed between the post-operative results and the predicted gas from the software algorithm. The results showed that the native gaps are neither symmetric nor equal. In addition, aiming for equal gaps reduces the variation at these angles but could result in mid- flexion laxity. Advanced robotics-assisted instrumentation can aid in evaluation of soft-tissue and help in surgical planning of TKA. This allows the surgeon to achieve the targeted outcome as well as record the final implant tension to correlate with clinical outcomes.

As a treatment for end-stage elbow joint arthritis, total elbow replacement (TER) results in joint motions similar to the intact joint; however, bearing wear, excessive deformations and/or early fracture may necessitate early revision of failed implant components. Compared to hips, knees and shoulders, very little research has been focused on the evaluation of the outcomes of TER, possible failure mechanisms and the development of optimal designs. The current study aims to develop computational models of TER implants in order to analyze implant behaviour; considering contact stresses, plastic deformations and damage progression.

A geometrical model of a TER assembly was developed based on measurements from a Coonrad-Morrey TER implant (Zimmer, Inc., Warsaw, IN). Ultra high molecular weight polyethylene (UHMWPE) nonlinear elasto-plastic material properties were assigned to the humeral and ulnar bushings. A frictional penalty contact formulation with a coefficient of friction of 0.04 was defined between all of the surfaces of the model to take into account every possible interaction between different implant components in vivo. The loading scenario applied to the model includes a flexion-extension motion, a joint force reaction with variable magnitude and direction and a time varying varus-valgus (VV) moment with a maximum magnitude of 13 N.m, simulating a chair-rise scenario as an extreme loading condition. An explicit dynamic finite element solver was used (ABAQUS Explicit, Dassault Systèmes, Vélizy-Villacoublay, France), due to improved capabilities when performing large deformation analyses. Model results were compared directly with corresponding experimental data. Experimental wear tests were performed on the abovementioned implants using a VIVO (AMTI, Watertown, MA) six degree-of-freedom (6-DOF) joint motion simulator apparatus. The worn TER bushings were scanned after the test using micro computed tomography (µCT) imaging techniques, and reconstructed as 3D models. Comparisons were made based on the sites of damage and deformed geometries between the numerical results and experimental test data. In addition to that, parametric geometrical models were developed using worn geometry of the retrievals in order to account for primary wear and deformations while simulating long-term contact stress and secondary damage progression on the bushings (Fig. 1).

Contact pressure distributions on the humeral and ulnar bushings correlate with the sites of damage as represented by the µCT data and gross observation of clinical retrievals. Furthermore, deformation patterns and kinematics of the components are in good agreement with the experimental results (Fig.2). Excessive plastic deformations are evident in both the numerical and the experimental results close to the regions with high contact pressures. Simulating parametric initially-worn geometries results in the formation of secondary damage zones, as well as redistribution of contact stresses and contact locations (Fig. 3).

The results demonstrate UHMWPE bushing damage due to different loading protocols. Numerical results demonstrate strong agreement with experimental data based on the location of deformation and creep on bushings and exhibit promising capabilities for predicting the damage and failure mechanisms of TER implants.

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Patients with osteoarthritis (OA) of the knee commonly alter their movement to compensate for deficiencies. This study presents a new numerical procedure for classifying sit-to-walk (STW) movement strategies.

Ten control and twelve OA participants performed the STW task in a motion capture laboratory. A full body biomechanical model was used. Participants were instructed to sit in a comfortable self-selected position on a stool height adjusted to 100% of their knee height and then stand and pick up an object from a table in front of them. Three matrices were constructed defining the progression of the torso, feet and hands in the sagittal plane along with a fourth expressing the location of the hands relative to the knees. Hierarchical clustering (HC) was used to identify different strategies. Trials were also classified as to whether the left (L) and right (R) extremities used a matching strategy (bilateral) or not (asymmetrical). Fisher's exact test was used to compare this between groups.

Clustering of the torso matrix dichotomised the trials in two major clusters; subjects leaning forward (LF) or not. The feet and hands matrices revealed sliding the foot backward (FB) and moving an arm forward (AF) strategies respectively. Trials not belonging in the AF cluster were submitted to the last HC of the fourth matrix exposing three additional strategies, the arm pushing through chair (PC), arm pushing through knee (PK) and arm not used (NA). The control participants used the LF+FBR+PK combination most frequently whereas the OA participants used the AFR+PCL. OA patients used significantly more asymmetrical arm strategies, p=0.034.

The results demonstrated that control and OA participants favour different STW strategies. The OA patients asymmetrical arm behaviour possibly indicates compensating for weakness of the affected leg. These strategy definitions may be useful to assess post-operative outcomes and rehabilitation progress.

Objectives

Sagittal alignment of the lumbosacral spine, and specifically pelvic incidence (PI), has been implicated in the development of spine pathology, but generally ignored with regards to diseases of the hip. We aimed to determine if increased PI is correlated with higher rates of hip osteoarthritis (HOA). The effect of PI on the development of knee osteoarthritis (KOA) was used as a negative control.

Objectives

The aim of this study was to examine whether asymmetric loading influences macrophage elastase (MMP12) expression in different parts of a rat tail intervertebral disc and growth plate and if MMP12 expression is correlated with the severity of the deformity.

Purpose

Dislocation after revision total hip is a common complication. The purpose of this study was to assess whether a large femoral head (36/40mm) would result in a decreased dislocation rate compared to a standard head (32mm).

Purpose

There is a postulated association between increased serum metal ions and pseudotumour formation in patients with metal-on-metal hip replacements. The primary aim of this study was to assess the prevalence of pseudotumour in 31 asymptomatic patients with a large femoral head (LFH) metal-on-metal hip implant. This was compared to the prevalence of pseudotumour in 20 matched asymptomatic patients with a hip resurfacing (HRA) and 24 matched asymptomatic patients with a standard metal-on-polyethylene (MOP) total hip. A secondary objective was to assess possible correlation between increased serum metal ions and pseudotumour formation

Purpose

Electrothermal arthroscopic capsulorrhaphy (ETAC) was a technology introduced for orthopaedic surgery without good scientific clinical evidence supporting its use. This multicentre randomized clinical trial provides the scientific clinical evidence comparing ETAC to Open Inferior Capsular Shift (ICS), by measuring disease-specific quality of life at 2-years post-operatively, in patients with shoulder instability due to capsular redundancy.

Purpose

This prospective, expertise-based randomized clinical trial compares arthroscopic to open shoulder stabilization by measuring the disease-specific quality of life outcome in patients with traumatic unidirectional anterior shoulder instability, and determining the incidence of recurrent instability at 2-years post-operatively.

Purpose

The outcome following isolated liner exchange for revision knee arthroplasty, while an attractive option for its simplicity, has a mixed outcome reported in the literature. We report our experience in patients who had a minimum of two years follow-up.

Purpose

The purpose of this study was to compare and evaluate the cost-effectiveness of the MIS Anterolateral Approach to that of the MIS Posterolateral and MIS Direct Lateral Approach.

Introduction

Bearing surfaces used for total hip arthroplasty must have characteristics including bio-compatibility, low friction and low wear rate. Bearing combinations are generally characterised as Soft on Hard/Hard. In general, all newer bearing combinations have reduced wear but may present with other issues that impact on patient outcomes.

Introduction

Bone morphogenetic proteins (BMPs) are members of the TGF-beta superfamily of growth factors and are known to regulate proliferation and expression of the differentiated phenotype of chondrocytes, osteoblasts, and osteoclasts. To investigate the osteoblastic differentiation gene expressions that contribute to BMP-7 dependent ostogenesis, we performed gene expression profiling of BMP-7-treated mouse bone marrow stromal cells.

Purpose: Between 1 and 2% of knee arthroplasties are complicated by infection with its associated patient morbidity. Two stage revision remains the gold standard with the minimum interval considered acceptable between the two stages as 6 weeks, but in some cases can be considerably longer depending on the patients’ clinical response to the first stage and intravenous antibiotics. The interval between the 2 stages is to allow eradication of the causative organism, however, this can result in considerable morbidity for the patient. Patients often have a poor range of movement, instability and considerable discomfort during this time and as a result have poor mobility. Further complications can be encountered at the time of the 2nd stage with considerable scarring of the soft tissues, in part secondary to the lack of mobilisation. Traditionally, spacers which are non-articulating have been used, however, problems of instability, scarring and bone erosion have been reported in the literature. The Prostalac knee spacer constitutes an antibiotic loaded acrylic cement body with a metal on polyethylene surface and enables the patient to undergo rehabilitation in the interval between the 2 stages and may also help maintain soft tissue planes as a result. Previous published results with a mean follow up of 48 months suggest the spacer is just as successful at eradicating infection (91%) as other techniques. The aim of this study is to review 119 patients with a minimum follow up of 5 years.

Method: The Prostalac Knee spacer has 2 components, a femoral and a tibial. Each are made of antibiotic-loaded acrylic cement with a small articulation of metal on polyethylene. The spacers are made from moulds so that a component of a suitable size and thickness could be made. This was a retrospective review of 119 consecutive patients. The inclusion criteria included all patients who had undergone a 2 stage revision with the Prostalac Knee spacer who had more than 5 years of follow up. Patients were assessed using the WOMAC, SF-12, Oxford Knee Score and the Knee Society Score.

Results: Thirteen patients (10.9%) out of a total of 119 had recurrence of infection. This gives an overall rate of control of infection of 89%. Of the 46 patients who completed the outcome score questionnaires with more than 5 years follow up, the mean WOMAC score was 65.9, Oxford Knee score was 61, SF-12 (physical component) was 35.7, SF-12 (mental component) was 54.8.

Conclusion: Although the Prostalac components include polyethylene and metal, they do not seem to have a detrimental impact on the rate of control of infection since our results were similar to those previously reported with other best practice techniques. It is our impression that the Prostalac functional spacer allows earlier pain free mobilisation, allowing the potential for earlier hospital discharge. The savings obtained from earlier hospital discharge greatly outweighing the increased cost of the Prostalac functional spacer system.

Purpose: The reverse total shoulder arthroplasty (RTSA) has shown improvement in both pain control and function in recent studies. The purpose of this study was to prospectively analyze functional outcomes and strength in patients following the use of the Delta III prosthesis in a single center.

Method: Patients treated by one of two surgeons were prospectively evaluated following RTSA. An independent observer administered the Constant Score, SF-12, Shoulder Osteoarthritis (SOAQ), ASES, DASH questionnaires and patient satisfaction. Isometric strength testing was performed using the Powertrack II dynamometer. Follow-up for all patients was available up to 5 years following surgery.

Results: The Delta III RTSA was performed on 51 study patients (67% female, mean age 74 (SD=10)). Improvements following surgery were noted in Quality of life (SF-12 Physical Summary= 30 to 38); shoulder disability (SOAQ= 144 to 79; ASES 7 to 15; DASH= 61 to 46; Constant 21 to 56), Symptoms (SOAQ symptoms 40 to 22), Physical impairments as determined by strength (External rotation = 3 to 5 Nm, Abduction 4 to 10 Nm); and ROM (Flexion= 51 to 115°, abduction 45 to 106°); p< 0.05. All patients had follow up between 2–5 years. Satisfaction was high (86% extremely, 3% not at all).

Conclusion: Our data demonstrates significant improvements in quality of life, symptoms, patient satisfaction and disability with reduced and high at more than 2 years following RTSA. Novel to this study is improved objective evidence of strength in functional planes of motion. This is the first Canadian study to demonstrate such improvements in patients following RTSA.

Purpose: The purpose of this study was to identify if preoperative pain scores predict postoperative pain and functional outcomes in patients following rotator cuff surgery and if a threshold where increased risk occurs could be established. Establishing a risk threshold may help identify patients who need increased follow-up or rehabilitation.

Method: One hundred six subjects with rotator cuff pathology requiring operative intervention were prospectively followed. The pain subscale of the Shoulder Pain and Disability Index (SPADI) was used as an indicator of pre-operative pain. Postoperative function one year following surgery was determined using the Simple Shoulder Test (SST). Scores with 40% or more deficit (compared to age matched controls) were classified as poor outcomes. The relative risk (RR) of poor SST scores was calculated across different cutoffs for preoperative pain scores.

Results: Having a high preoperative pain score was associated with a poor outcome following rotator cuff surgery at both the six month and one year followup. Preoperative pain scores did predict postoperative functional scores. As preoperative pain levels increased there was a higher risk of poor functional outcomes. The RR of having a poor SST at 1-year was 2.3, if preoperative pain score was greater than 35/50.

Conclusion: The current study indicates that those patients with high preoperative pain scores (> 35/50 or > 70%) are more than twice as likely to have a poor outcome following rotator cuff surgery. This should inform patients and surgeons for postoperative expectations. Whether closer follow-up, pre-rehabilitation, more intensive postoperative rehabilitation or enhanced pain management can alter this prognosis warrants investigation.

Purpose: This prospective, randomized double-blinded clinical trial compared cemented fixation of the humeral component to uncemented/tissue-in-growth fixation in total shoulder arthroplasty for primary osteoarthritis of the shoulder.

Method: All patients presenting with primary osteoarthritis of the shoulder requiring replacement were screened for eligibility. Patients were randomized in the operating room after glenoid preparation to the cemented or uncemented group by a computer-generated, stratified randomization procedure. Outcome measures included disease specific QOL assessment (WOOS), SF-12, ASES, MACTAR, radiographic evaluation of component fixation, operative time, complications and revision surgery. Patients were assessed by a blinded evaluator in post-operative intervals of 2 and 6 weeks, and 3, 6, 12, 18, and 24 months. The primary endpoint was the WOOS score at 2 years.

Results: One hundred and sixty-one patients were consented and randomized for the study. There were 80 patients in the cemented and 81 patients in the uncemented group. At baseline, the groups were alike with regards to demographics and baseline evaluations. The WOOS scores at post-operative intervals of 12, 18 and 24 months showed a significant difference (p=0.009, 0.001, 0.028 respectively) in favour of the cemented group. The cemented group also had better strength (3 m p=0.038, 12 m p= 0.036, 18 m p=0.051, 24 m p=0.053) and forward flexion (6m p=0.031, 12 m p=0.04). As expected, the operative time was significantly less for the uncemented group (C = 2.26h +/−.63; U = 1.69h +/− 1.9, p= 0.03).

Conclusion: These findings provide the first evidence that cemented fixation of the humeral head provides better quality of life, strength and ROM than uncemented fixation. This was a Tier 1 Project of the JOINTs Canada group.

Purpose: Shoulder instability is a common problem affecting patients in their most active years resulting in an impact on their quality of life. The WOSI is a validated, disease-specific (shoulder instability) evaluative quality of life measure. It has not been tested for its ability to discriminate between those who require surgical care and those who do not. The purpose of this study is to determine if the WOSI can discriminate between surgical and non-surgical patients and between patients with different types of shoulder instability.

Method: Sixty patients with a confirmed diagnosis of shoulder instability were included as cases. Twenty had documented multidirectional instability requiring surgery: Group 1 Surgical MDI – 20 patients had documented recurrent traumatic anterior dislocations requiring surgery: Group 2 Surgical Anterior – 20 patients were first time anterior dislocators who were followed for a minimum one year who had no further recurrences and did not require surgery: Group 3 Non-Surgical First Time Anterior – The cases were compared to 60 age and gender matched control patients with no history of shoulder problems: Group 4 Control – WOSI scores were analyzed using a one-way ANOVA.

Results: The WOSI scores were as follows: Group 1 Surgical MDI- mean 30.5 (95% CI 23.1–37.8); Group 2 Surgical Anterior- mean 39.8 (95% CI 33.1–46.5); Group 3 Non-Surgical First time Anterior- mean 76.2 (95% CI 66.4–86.0) and Group 4 Control- mean 96.6 (95% CI 95.8–97.4). Based on the 95% Confidence Intervals, there were statistically significant differences between the two surgical groups (Group 1 Surgical MDI and Group 2 Surgical Anterior) compared to the non-surgical patients (Group 3 Non Surgical First Time Anterior) and the controls (P=0.000). There is a trend to discriminate between the two surgical groups (P=0.079).

Conclusion: The WOSI Index clearly discriminates between surgical and non-surgical patients with shoulder instability, and the control population with normal shoulders. There is a trend to discriminate between MDI and recurrent anterior traumatic dislocators.

The non-operative treatment of idiopathic clubfoot has become increasingly accepted worldwide as the initial standard of care. The Ponseti method has become particularly popular as a result of published short and long-term success rates in North America. Non-compliance with abduction bracing has been proven to be a major risk factor for recurrence of clubfoot. The purpose of this retrospective study was to identify those patients who were non-compliant with the abduction bracing post casting and to then assess the rate and severity of recurrence.

One-hundred and fifty children (184 feet) with unilateral or bilateral clubfoot who were treated with the Ponseti method by the senior author from 1999 to 2008 were reviewed. We identified those patients who were non-compliant with the abduction bracing. Compliance was defined as three months full time wear followed by twelve months night-time/nap-time wear. Recurrence was classified as minor, defined as those requiring an extra-articular surgical procedure and major, requiring an intra-articular procedure.

We identified fifty children with seventy clubfeet who were followed up for a minimum of 12 months. None of these patients were compliant with brace wearing. Of the 70 feet, 40 (57%) required surgical intervention. There were 30 (43%) feet with no clinical recurrence. In 5 of the bilateral cases only one of the feet had required corrective surgery. In the 29 patients who required surgical intervention we identified 52 procedures (37 extra-articular and 15 intra-articular).

Compliance with the post correction abduction bracing protocol is crucial to avoid recurrence of a clubfoot deformity treated with the Ponseti method. Despite non-compliance however there is a significant proportion of patients who do not require any surgical intervention. We recommend initiating the Ponseti technique on all patients with clubfeet rather than being selective due to anticipated compliance issues with the family.

UK military forces have been deployed in Afghanistan since 2006 as part of the International Stabilisation Assistance Force. The Operation is supported by a 50-bedded hospital. In 2007 the Defence Medical Services introduced a massive haemorrhage policy. In asymmetric warfare gunshot wounds (GSW), improvised explosive devices (IED) and mine injuries are prevalent and we hypothesized that they would require significant blood products.

We prospectively collected data from consecutive trauma resuscitations over 3 months (January to March 2008). Pre-hospital time points, mechanism of injury, injury distribution, injury severity score (ISS), new injury severity score (NISS), surgical procedures, blood product utilisation and outcome were recorded.

115 trauma resuscitations were performed over the study period. Median pre-hospital time was 95 minutes (range 30–325), with median 64 minutes to the arrival of the Medical Emergency Response Team helicopter. The cause of injury was landmine (20), IED (31) and GSW (40); mean number of involved body systems was 1.4, 1.8 and 1.5 respectively and injured structures 2.8, 3.5 and 2.3 respectively (IED> GSW p< 0.05). Mean ISS was 16, 16.8, 14.9 and NISS 18.7, 20.9, and 17.9 respectively. Blood transfusion was required in 3 mine, 14 IED and 17 GSW casualties (mine< IED & GSW, p< 0.05) with 10.6, 11.4, and 13.9 units of blood transfused per casualty.

Injury severity for casualties is high with multiple injuries to body systems irrespective of mechanism. Anti-personnel mine injuries were significantly less likely to require transfusion. Large quantities of blood products were still required when necessary in all mechanisms of trauma. It is therefore recommended that during the pre-hospital time the major transfusion protocol should be placed on stand-by.

Purpose: Use of six-axis analysis and computer assisted deformity correction via a circular external fixator is a new method for deformity correction. We investigated its accuracy and safety in reconstruction of femoral deformity in children and young adults.

Method: We retrospectively reviewed all cases including the indications for use and the methodology of application of the computer assisted six-axis analysis and circular external fixator for reconstruction of 22 femora in 20 patients. Twelve patients were female, and 8 were male. The average age was 13.9 (range, 5.9–24.6). Etiology included traumatic (7), idiopathic (6), multiple enchondromatosis (2), rickets (2), congenital femoral deficiency (2), spondyloepiphyseal dysplasia (1), congenital pseudohypoparathyroidisim (1), and multifocal osteomyelitis (1). Clinical and radiographic data were analyzed.

Results: Average follow-up was 14.4 months (range, 4.5–32). Average time in frame was 6.2 months (range, 2.6–19). Bone lengthening of 3.9 cm (range, 1–8.5) was performed in 12 femora. In genu valgum patients, the mLDFA improved from a mean of 73.7° to a mean of 89°. In genu varum patients, the mLDFA improved from a mean of 99.8° to a mean of 89.5°. Complications included pin tract infection in 6, knee stiffness in 3, delayed union in 2, skin irritation in 1, posterior knee subluxation in 2, both of which had stable knees preoperatively. One patient was lost to follow-up and returned back with deformity. No complications occurred in 8 patients.

Conclusion: Computer assisted femoral deformity correction with six-axis analysis and application of circular external fixator is a useful technique with the advantage of managing multiplanar deformities in children and young adults. It has the potential complications of the use of any external fixator. Close follow-up is necessary to avoid subluxation of the knee joint even in patients with stable knees. Accurate and safe correction can be achieved in almost all patients.

We suggested a new concept of buffered implant fixation. It is a cementless fixation using a buffer instead of the cement between the bone and the implant. We investigated the feasibility of the buffered implant fixation using a rat model. In our previous study, we measured the amount of bone around the implant to compare the buffered implant fixation with the cemented fixation. The results showed the difference in change of Bone Volume/Total Volume (BV/TV) with time between the buffered fixation and the cemented fixation. Now, in this study, we are comparing the mechanical interface strength between two fixations.

After micro CT scanning, the specimens were used for mechanical push-out test to measure the interface shear strength at the buffer-bone or cement-bone interface. The distal side of the femur was carefully removed to expose the whole distal region of the implant while the proximal side of femur was cut carefully with diamond saw (Metsaw, R& B Inc., Korea) until the proximal end of cement or buffer is exposed. The femur was embedded into a push-out jig with a plaster. The push-out jig was mounted in a material testing machine (KSU-10M, Kyungsung testing machine, Korea) and loaded at a rate of 0.01mm/s. The apparent interface strength was calculated by dividing the peak force by the surface area of the buffer or cement.

After 2 weeks, the apparent interface strength is 217.0 ± 280.0(average ± standard deviation) for buffer and 472.4 ± 381.1 for cement; after 4 weeks, 92.9 ± 67.6 and 268.1 ± 197.9; after 12 weeks, 441.9 ± 467.1 and 201.8 ± 132.3, respectively. The buffered fixation showed gain in strength with time while the cemented fixation showed reverse tendency but the interaction by ANOVA was not significant (p=0.125). Even though the excellence of buffer fixation was not clearly confirmed because of small sample size and high variance, the feasibility of the buffer fixation was shown.

However, further studies are necessary to improve the buffered implant fixation. To enhance the cell adhesion and biocompatibility, it is necessary to modify the surface of polyetheretherketone (PEEK) such as by plasma treatment or biological coating. Also, an animal test using a higher level animal such as dog or pig is necessary.

Purpose: Waterproof casts have been shown to be a safe and effective means of immobilization in children with minimally displaced fractures. The purpose of this study was to determine if waterproof Gore-Tex-lined casts are as effective as traditional cotton-lined casts in the immediate postoperative period after closed reduction of displaced distal radius fractures in children.

Method: We performed a retrospective review of distal radius fractures that underwent closed reduction and application of a long-arm cast between June 2004 and December 2006. A total of 124 cases were included (55 Gore-Tex; 69 traditional cotton-lined). The primary outcome measure was redisplacement in the cast. The cast index was also used to assess the quality of cast molding. Data was analyzed using repeated measures ANOVA. Power analyses were also conducted.

Results: There were no significant differences between the two groups with regards to translation of the radius or angulation of the radius on anterior-posterior (AP) and lateral radiographs at the time of injury, postreduction, or cast removal. Redisplacement as measured by the change in translation of the radius and angulation of the radius on AP and lateral radiographs from the time of reduction to cast removal was also not significantly different between the two groups. The mean cast index for the Gore-Tex and traditional cotton-lined groups was 0.882 and 0.873 respectively, which was not a significant difference.

Conclusion: A waterproof Gore-Tex-lined cast will maintain fracture reduction as well as a cotton-lined cast for closed reductions of distal radius fractures in children in the immediate postreduction period. Waterproof casts also provide extensive benefits to the patient with regards to bathing, hygiene, and participation in aquatic activities

Spontaneous osteonecrosis of the knee (SPONK) usually involves a single condyle or plateau. The medial femoral condyle is most often involved and spontaneous osteonecrosis of medial tibial plateau is a rare condition, representing only 2 % of all necrosis reported in the knee. Therefore, SPONK with both involvement of medial femoral condyle(MFC) and medial tibial plateau(MTP) might be extremely rare. SPONK in each MFC or MTP respectively might be extended into corresponding side of the knee at their advanced final stage, howevere, in that situations, significant degenerative change would accompany and it might be difficult to differentiate final staged SPONK form severe osteoarthritis. To the best of our knowledge, SPONK affecting both medial femoral condyle and medial tibial plateau without significant secondary osteoarthritis changes is not reported, even though it was difficult to know which occurred first. We experienced 3 patients with histologically proven osteonecrosis of the medial tibial condyle and medial tibial plateau, and report their radiologic features. All 3 patients showed similar ridiograhic patterns. Medial portion of medial tibial plateau and lateral portion of medial femoral condyle showed longitudinal fracture like-subchondral collapse. Standing anteroposterior radiograph at 30 degree knee flexion showed well fitted features such as “locked” medial condyle. Varus angulation was present. Significant degenerative changes was not shown except for subchondral sclerosis. T1-weighted coronal and Fat suppressed T2-weighted MR images showed subchondral collapse with ill-defined diffuse bone marrow edema changes on both tibial and femoral condyles. At surgical findings, longitudinal track-like groove was shown in both medial femoral condyle and medial tibial plateau. Articular cartilage was denuded and showed glistening surface with bone defect of lateral side of medial femoral condyle and medial side of tibial articular surface. Histological analysis shows necrotic bone, surrounded by an area of fibrovascular granulation tissue on both femoral and tibial sides. Total knee arthoplasty was performed in all 3 patients. As a result of very low prevalence of both involvement of MFC and MTP and limited number of our cases, we could not conclude that radiologic features in our cases are typical radiologic pattern of both involvement. However, based on our cases, we believe that this characteristic radiologic features may considered as one of the possible various radiologic findings of simultaneous involvement in MFC and MTP and allow diagnosis for SPONK with both involvement in MFC and MTP to be facilitated.

Purpose: Porous tantalum has been shown to be very effective in achieving bone ingrowth. However, in some circumstances, bone quality or quantity is insufficient to allow adequate bone ingrowth. We hypothesized that the addition of alendronate to porous tantalum would enhance the ability of porous tantalum to achieve bone ingrowth in these challenging situations, such as when a gap exists between the implant and bone. We evaluated the effect of alendronate coated porous tantalum on new bone formation in an animal model incorporating a gap between implant and bone.

Method: Thirty-six cylindrical porous tantalum implants were bilaterally implanted into the distal femur of 18 rabbits for 4 weeks. There were 3 groups of implants inserted; a control group of porous tantalum with no coatings, porous tantalum with micro-porous calcium phosphate coating, and porous tantalum coated with micro-porous calcium phosphate and alendronate. Subcutaneous fluorescent labeling was used to track new bone formation. Bone formation was analyzed by backscattered electron microscopy and fluorescent microscopy on undecalcified samples.

Results: The relative increase in mean volume of gap filling, bone ingrowth and total bone formation was 143% (p< 0.001), 259% (p< 0.001) and 193% (p< 0.001) respectively in the alendronate coated porous tantalum compared with the uncoated porous tantalum controls. The relative increase in the percentage of new bone-implant contact length was increased by 804% on average in the alendronate coated porous tantalum compared with the uncoated tantalum controls.

Conclusion: This study demonstrated the significant enhancement of bone-implant gap filling and bone ingrowth which can be achieved by coating porous tantalum with alendronate. It is proposed that, when faced with the clinical problem of revision joint replacement in the face of bone loss (at the hip, knee or elsewhere), the addition of an alendronate-delivery surface coating would enhance biological fixation of the implant and promote the healing of bone defects.