Future demand for primary hip and knee arthroplasty in Scotland.

INTRODUCTION: The rising prevalence of osteoarthritis, associated with an ageing population, is expected to deliver increasing demand for arthroplasty services in the future. Understanding the scale of potential change is essential to ensure adequate provision of services and prevent prolonged waiting times that can cause patient harm. METHODS: We set out to provide projections of future primary knee and hip arthroplasty out to 2038 utilising historical trend data (2008-2018) from the Scottish Arthroplasty Project. All analyses were performed using the Holt's exponential smoothing projection method with the forecast package in R statistics. Results were adjusted for projected future population estimates provided by National Records of Scotland. Independent age group predictions were also performed. RESULTS: The predicted rise of primary hip arthroplasty for all ages is from 120/100k/year in 2018 to 152/100k/year in 2038, a 28% increase. The predicted rise of primary knee arthroplasty for all ages is from 164/100k/year in 2018 to 220/100k/year in 2038, a 34% increase. Based on a static 3-day length of stay average this would see 4280 and 7392 additional patient bed days required for primary hip and knee arthroplasty patients respectively per annum. The associated additional cost is anticipated to be approximately £26 million. CONCLUSIONS: Anticipated future demand for arthroplasty will require significant additional resource and funding to prevent deterioration in quality of care and an increase in patient wait times, additional to that already required to clear the COVID-19 backlog. Understanding presented projections of changes to arthroplasty demand is key to future service delivery.

Prioritisation of patients awaiting hip and knee arthroplasty: Lower pre-operative EQ-5D is associated with greater improvement in quality of life and joint function.

INTRODUCTION: The COVID-19 pandemic has led to unprecedented delays for those awaiting elective hip and knee arthroplasty. Current demand far exceeds available resource, and therefore it is integral that healthcare resource is fairly rationed to those who need it most. We therefore set out to determine if pre-operative health-related quality of life assessment (HRQoL) could be used to triage arthroplasty waiting lists. METHODS: Data regarding demographics, perioperative variables and patient reported outcome measures (PROMs) (pre-operative and 1-year post-operative EuroQOL five dimension (EQ-5D-3L) and Oxford hip and knee scores (OHS/OKS) were retrospectively extracted from electronic patient health records at a large university teaching hospital. Patients were split into two equal groups based on pre-operative EQ-5D TTO scores and compared (Group1 [worse HRQoL] = -0.239 to 0.487; Group2 [better HRQoL] = 0.516-1 [best]). RESULTS: 513 patients were included. Patients in Group1 had significantly greater improvement in post-operative EQ-5D-3L scores compared to Group2 (Median 0.67 vs. 0.19; p < 0.0001), as well as greater improvement in OHS/OKS (Mean 22.4 vs. 16.4; p < 0.0001). Those in Group2 were significantly less likely to achieve the EQ-5D-3L minimum clinically important difference (MCID) attainment (OR 0.13, 95%CI 0.07-0.23; p < 0.0001) with a trend towards lower OHS/OKS MCID attainment (OR 0.66, 95%CI 0.37-1.19; p = 0.168). There was no clinically significant difference in length of stay (Median 3-days both groups), and no statistically significant difference in adverse events (30 days and 1 year readmission/reoperation). CONCLUSIONS: A pre-operative EQ-5D-3L cut-off of ≤0.487 for hip and knee arthroplasty prioritisation may help to maximise clinical utility and cost-effectiveness in a limited resource setting post COVID-19.

A new method for investigating osteoarthritis using Fast Field-Cycling nuclear magnetic resonance.

Osteoarthritis in synovial joints remains a major cause of long-term disability worldwide, with symptoms produced by the progressive deterioration of the articular cartilage. The earliest cartilage changes are thought to be alteration in its main protein components, namely proteoglycan and collagen. Loss of proteoglycans bound in the collagen matrix which maintain hydration and stiffness of the structure is followed by collagen degradation and loss. The development of new treatments for early osteoarthritis is limited by the lack of accurate biomarkers to assess the loss of proteoglycan. One potential biomarker is magnetic resonance imaging (MRI). We present the results of a novel MRI methodology, Fast Field-Cycling (FFC), to assess changes in critical proteins by demonstrating clear quantifiable differences in signal from normal and osteoarthritic human cartilage for in vitro measurements. We further tested proteoglycan extracted cartilage and the key components individually. Three clear signals were identified, two of which are related predominantly to the collagen component of cartilage and the third, a unique very short-lived signal, is directly related to proteoglycan content; we have not seen this in any other tissue type. In addition, we present the first volunteer human scan from our whole-body FFC scanner where articular cartilage measurements are in keeping with those we have shown in tissue samples. This new clinical imaging modality offers the prospect of non-invasive monitoring of human cartilage in vivo and hence the assessment of potential treatments for osteoarthritis. Keywords: Fast Field-Cycling NMR; human hyaline cartilage; Osteoarthritis; T1 dispersion; quadrupolar peaks; protein interactions.

Towards applying NMR relaxometry as a diagnostic tool for bone and soft tissue sarcomas: a pilot study.

This work explores what Fast Field-Cycling Nuclear Magnetic Resonance (FFC-NMR) relaxometry brings for the study of sarcoma to guide future in vivo analyses of patients. We present the results of an ex vivo pilot study involving 10 cases of biopsy-proven sarcoma and we propose a quantitative method to analyse 1H NMR relaxation dispersion profiles based on a model-free approach describing the main dynamical processes in the tissues and assessing the amplitude of the Quadrupole Relaxation Enhancement effects due to 14N. This approach showed five distinct groups of dispersion profiles indicating five discrete categories of sarcoma, with differences attributable to microstructure and rigidity. Data from tissues surrounding sarcomas indicated very significant variations with the proximity to tumour, which may be attributed to varying water content but also to tissue remodelling processes due to the sarcoma. This pilot study illustrates the potential of FFC relaxometry for the detection and characterisation of sarcoma.

A systematic review of tranexamic acid in hip fracture surgery.

AIM: To systematically examine and quantify the efficacy and safety of tranexamic acid in hip fracture surgery. METHODS: A systematic literature search was conducted using Medline, EMBASE, AMED, CiNAHL, and the Cochrane Central Registry of Controlled Trials. Two assessors independently screened search outputs for potentially relevant articles which met the eligibility criteria. The primary outcome measure was requirement of post-operative blood transfusion. Risk of bias assessment was performed using the Cochrane Collaboration's risk of bias tool for randomized controlled trials (RCTs) and the ROBINS-I tool for observational studies. Meta-analysis was performed to estimate risk ratio (RR), risk difference (RD) and mean difference (MD) values for dichotomous and continuous data outcomes, respectively. The interpretation of each outcome was made using the GRADE approach. RESULTS: Of 102 studies identified, seven met the inclusion criteria including a total of 770 participants (TXA: 341; Control: 429). On meta-analysis, intravenous TXA resulted in a 46% risk reduction in blood transfusion requirement compared to a placebo/control group (RR: 0.54; 95% CI: 0.35-0.85; I2 : 78%; Inconsistency (χ2 ) P = <0.0001; n = 750). There was also a significantly higher post-operative haemoglobin for TXA versus placebo/control (MD: 0.81; 95% CI: 0.45-1.18; I2 : 46%; Inconsistency (χ2 ) P = 0.10; n = 638). There was no increased risk of thromboembolic events (RD: 0.01; 95% CI: -0.03, 0.05; I2 : 68%; Inconsistency (χ2 ) P = 0.007, n = 683). CONCLUSION: There is moderate quality evidence that TXA reduces blood transfusion in hip fracture surgery, with low quality evidence suggesting no increased risk of thrombotic events. These findings are consistent with TXA use in other orthopaedic procedures.

A longitudinal MRI study of muscle atrophy during lower leg immobilization following ankle fracture.

PURPOSE: To investigate MRI biomarkers of muscle atrophy during cast immobilization of the lower leg. MATERIALS AND METHODS: Eighteen patients (8 male, 10 female), who had one lower leg immobilized in a cast, underwent 3.0 Tesla (T) MR imaging 5, 8, 15, 29, and 43 days after casting. Measurements were made on both lower legs of total muscle volume. Cross-sectional area (CSA), fractional water content, and T(2) were measured in tibialis anterior (TA), gastrocnemius medialis (GM) and lateralis (GL) and soleus (SOL). Fiber pennation angle was measured in GM. RESULTS: Total muscle volume decreased by 17% (P < 0.001) over the 6 weeks of immobilization. The greatest loss in CSA (mean[SD]) was seen in GM (-23.3(8.7)%), followed by SOL (-19.0(9.8)%), GL (-17.1(6.5)%), and TA (-10.7(5.9)%). Significant reductions of CSA were also detectable in the contra-lateral leg. T(2) increased in all muscles: TA 27.0(2.5) ms to 29.6(2.8) ms (P < 0.001), GM 34.6(2.9) ms to 39.8(5.4) ms (P < 0.001) and SOL 34.4 (2.9) ms to 44.9(5.9) ms (P < 0.001). Small reductions were found in fractional water content. Pennation angle decreased in the cast leg (P < 0.001). CONCLUSION: Quantitative MR imaging can detect and monitor progressive biochemical and biophysical changes in muscle during immobilization.

Detection of osteoarthritis in knee and hip joints by fast field-cycling NMR.

It is known that in the early stages of osteoarthritis, the concentration of glycan proteins decreases in articular cartilage. This phenomenon is under active research to develop a means to characterize osteoarthritis accurately in the early stages of the disease, when still reversible. However, no method of quantification has yet shown clear success in this area. In this article, we propose a novel approach to detect glycan depletion using fast field-cycling NMR. This technique was previously reported to allow noninvasive measurement of protein concentration via the (14)N quadrupolar relaxation in certain amide groups. We have demonstrated that the articular cartilage exhibits clear quadrupolar peaks that can be measured by a benchtop fast field-cycling NMR device and which changes significantly between normal and diseased tissues (P < 0.01). This signal is probably glycan specific. The method may have potential for early evaluation of osteoarthritis in patients on fast field-cycling-MRI scanners currently under evaluation in the authors' laboratory.

Levels of systemic metal ions in patients with intramedullary nails.

BACKGROUND: It is being increasingly recognized that orthopedic implants are associated with adverse tissue responses, mediated by degradation products. Recent interest has been focused on the production of metal ions from hip arthroplasty. Few studies have reviewed fracture fixation devices and their metal ion production. METHODS: 61 subjects were enlisted into the study, with 3 subgroups. 21 subjects had Russell-Taylor intramedullary tibial nails in situ for 26 (21-32) months (316LVm stainless steel), 20 subjects had TriGen intramedullary tibial nails in situ for 43 (35-51) months (Ti-6Al-4V titanium alloy), and the remaining 20 subjects did not have any implant in situ and served as controls. Blood samples were taken and serum chromium, molybdenum, titanium, aluminium, and vanadium concentrations were measured using inductively coupled plasma (ICP) techniques. RESULTS: The 3 groups were matched for age, sex, and BMI. The subjects with Russell-Taylor nails had elevated levels of chromium (0.10 microg/L) with median concentrations 2.5 times higher than those of the control group. The subjects with TriGen nails had less significantly elevated levels of titanium (6.5 microg/L). INTERPRETATION: Stainless steel implants show significant differences from titanium implants in the dissemination of metal ions. Although the levels of chromium were elevated, the overall levels were modest when compared to published data regarding metal ion release and hip arthroplasty. Intramedullary nails are, however, often used in younger patients. If not removed, they may result in prolonged exposure to metal ions.

Novel use of Steinman pin in removal of broken interlocking screws.

Broken screws after interlocking nailing of long bones are commonly seen in Orthopaedic practice. Removal of such screws can be difficult particularly the distal part which is often held within the bone. We describe a simple technique of using Steinman pin to aid removal of broken screws in a case of non-union fracture tibia with broken interlocking nail and screws. Steinman pin being easily available and the reproducible technique make it a useful aid for removal of broken interlocking screws.

Impact of trochanteric heterotopic ossification on measurement of femoral bone density following cemented total hip replacement.

During a study of bone mineral density changes around cemented femoral implants, we recognized heterotopic ossification occurring regularly in a position anterior to the greater trochanter and proximal femur. The aim of this study was to describe the incidence, distribution, and effect of this ossification on periprosthetic DXA scans following primary cemented total hip replacement. One hundred eleven patients underwent postoperative DXA examinations measuring changes in bone mineral density with heterotopic ossification identified and localized on standard radiographs with confirmation using DXA subtraction imaging. Male gender and age within the male group were significantly associated with occurrence of heterotopic ossification (p = 0.003 and 0.046, respectively). Femoral stem type, weight, and body mass index had no significant effect (p = 0.525, 0.372, and 0.243, respectively). Examining the Gruen zones in all patients suggested a median (plus interquartile range) zone 1 density drop of 4% (-12% to +7%). When separated and analyzed for the effect of heterotopic ossification, the 45 patients with heterotopic ossification showed a 2-year density gain of +6% (-5% to +15%), whereas those without heterotopic ossification showed a loss of 8% (-14% to 0%), a significant difference (p < 0.001). Zone 2 also showed a significant difference (p = 0.048). We therefore recommend that affected zones should be identified and excluded from analysis at all time points. Without this precaution, researchers risk underestimating periprosthetic bone loss in their studies and reporting misleading conclusions.

Use of an Ilizarov fixator for deformity correction prior to revision knee arthroplasty.

Malalignment is associated with an increased rate of loosening of knee prostheses. We present a case of primary knee replacement failure due to pre-existing tibial deformity. Correction of the deformity and associated malalignment was undertaken using the Ilizarov osteotomy method prior to full knee revision surgery.