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"Metcalfe, Andrew"
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Which osteoarthritic gait features recover following total knee replacement surgery?
Gait analysis can be used to measure variations in joint function in patients with knee osteoarthritis (OA), and is useful when observing longitudinal biomechanical changes following Total Knee Replacement (TKR) surgery. The Cardiff Classifier is an objective classification tool applied previously to examine the extent of biomechanical recovery following TKR. In this study, it is further developed to reveal the salient features that contribute to recovery towards healthy function.
Gait analysis was performed on 30 patients before and after TKR surgery, and 30 healthy controls. Median TKR follow-up time was 13 months. The combined application of principal component analysis (PCA) and the Cardiff Classifier defined 18 biomechanical features that discriminated OA from healthy gait. Statistical analysis tested whether these features were affected by TKR surgery and, if so, whether they recovered to values found for the controls.
The Cardiff Classifier successfully discriminated between OA and healthy gait in all 60 cases. Of the 18 discriminatory features, only six (33%) were significantly affected by surgery, including features in all three planes of the ground reaction force (p<0.001), ankle dorsiflexion moment (p<0.001), hip adduction moment (p = 0.003), and transverse hip angle (p = 0.007). All but two (89%) of these features remained significantly different to those of the control group after surgery.
This approach was able to discriminate gait biomechanics associated with knee OA. The ground reaction force provided the strongest discriminatory features. Despite increased gait velocity and improvements in self-reported pain and function, which would normally be clinical indicators of recovery, the majority of features were not affected by TKR surgery. This TKR cohort retained pre-operative gait patterns; reduced sagittal hip and knee moments, decreased knee flexion, increased hip flexion, and reduced hip adduction. The changes that were associated with surgery were predominantly found at the ankle and hip, rather than at the knee.
Journal Article
Economic burden and cost-effectiveness of treatments for open tibia fractures in Malawi: Economic analysis of a multicentre prospective cohort study
Open tibia fractures result in substantial lifelong disability for patients, and are expensive to treat. As the injury typically affects young working men, the societal costs from open tibia fractures are likely to also be high in low income countries, but remain largely unknown. We therefore investigated the overall societal costs and cost-effectiveness of different orthopaedic treatments at one year following an open tibia fracture in Malawi.
This study was a cost-utility analysis nested in a prospective cohort study from the healthcare- and societal-payer perspectives with a one-year time horizon. We obtained quality-adjusted life years (QALYs) from the EuroQoL 5 Dimension 3 Level (EQ-5D-3L) and patient lost productivity estimates at 6 weeks, and 3, 6, and 12 months post-injury. QALYs were calculated from utility scores were modelled within a hierarchical Bayesian multivariate modelling framework that jointly estimated individual-level trajectories in EQ-5D-3L scores and costs over follow-up. Direct treatment costs were obtained from a micro-costing study, and staff interviews at tertiary and district hospitals. Cost-effectiveness was reported in terms of societal cost per quality-adjusted life year (QALY). All costs were reported in 2021 United States dollars (USD).
Between February 2021 and March 2022, 287 participants with open tibia fractures were included. There were substantial costs to participants one year following injury with 42% (n = 112) working with a median monthly household income of US$40 (IQR: US$7-90) compared to 89% (n = 255) working pre-injury, with a median monthly household income of US$60 (IQR: US$36-144). The posterior median of societal costs at one year varied between US$751 (80% credible intervals [CrIs]: US$-751-2,389) for treatment with plaster of Paris (POP) in a district hospital for a Gustilo III injury, to US$2,428 (80% CrIs: US$995-5027) for intramedullary nail in central hospital for a Gustilo III injury. The largest cost-effectiveness from a societal perspective was between an intramedullary nail and amputation for a Gustilo III injury with a posterior mean of US$2,290 (95%HDI: 36-4,547) per QALY.
The main finding was that open tibia fractures result in significant costs to patients, the healthcare system and society in Malawi. Although the funding of orthopaedic treatment can be difficult in countries with very limited healthcare budgets, the costs to society of ignoring this issue are very high. A re-balancing of health budgets (including from government and donors) is needed to prioritise trauma care to reduce the growing societal economic burden from injury.
Journal Article
Postnatal manipulation of Pax6 dosage reverses congenital tissue malformation defects
Aniridia is a congenital and progressive panocular condition with poor visual prognosis that is associated with brain, olfactory, and pancreatic abnormalities. Development of aniridia is linked with nonsense mutations that result in paired box 6 (PAX6) haploinsufficiency. Here, we used a mouse model of aniridia to test the hypothesis that manipulation of Pax6 dosage through a mutation-independent nonsense mutation suppression strategy would limit progressive, postnatal damage in the eye. We focused on the nonsense suppression drugs 3-[5-(2-fluorophenyl)-1,2,4-oxadiazol-3-yl]benzoic acid (ataluren) and gentamicin. Remarkably, we demonstrated that nonsense suppression not only inhibited disease progression but also stably reversed corneal, lens, and retinal malformation defects and restored electrical and behavioral responses of the retina. The most successful results were achieved through topical application of the drug formulation START (0.9% sodium chloride, 1% Tween 80, 1% powdered ataluren, 1% carboxymethylcellulose), which was designed to enhance particle dispersion and to increase suspension viscosity. These observations suggest that the eye retains marked developmental plasticity into the postnatal period and remains sensitive to molecular remodeling. Furthermore, these data indicate that other neurological developmental anomalies associated with dosage-sensitive genetic mutations may be reversible through nonsense suppression therapeutics.
Journal Article
Is knee osteoarthritis a symmetrical disease? Analysis of a 12 year prospective cohort study
Background
The aim of this study was to document the development of bilateral knee osteoarthritis over a 12 year period using a middle-aged population-based cohort with knee pain at inclusion.
Methods
One hundred and forty three patients aged 35 to 54 were recruited from a population based cohort of 279 subjects who had knee pain at baseline and assessed with clinical and radiographic data, with 5 and 12 year follow up. The data was analysed with regard to the development and progression of uni- and bilateral knee osteoarthritis over 12 years. A definition of KL = 1 was used to define radiographic disease.
Results
24 of the 30 (80%) patients with unilateral disease at baseline developed bilateral disease after 12 years. At baseline 37 patients (26%) had bilateral disease, whereas that number increased to 65 (52%) at 5 years and 100 (70%) at the 12 year follow up. The most common pattern was medial compartment involvement in both knees. Six patients had lateral compartment disease in one knee and medial in the other whereas only two had lateral compartment disease bilaterally.
Conclusions
Bilateral knee osteoarthritis is very common with time, as the majority of sufferers will eventually develop radiographic disease in both knees. Clinicians need to be aware of the ‘joint at risk’ and researchers need to remember to account for both knees when assessing the relationship between physical function, pain and structural disease. The other knee should not be used for comparison, even if it appears to be normal at baseline.
Journal Article
Using Bayesian adaptive designs to improve phase III trials: a respiratory care example
Background
Bayesian adaptive designs can improve the efficiency of trials, and lead to trials that can produce high quality evidence more quickly, with fewer patients and lower costs than traditional methods. The aim of this work was to determine how Bayesian adaptive designs can be constructed for phase III clinical trials in critical care, and to assess the influence that Bayesian designs would have on trial efficiency and study results.
Methods
We re-designed the High Frequency OSCillation in Acute Respiratory distress syndrome (OSCAR) trial using Bayesian adaptive design methods, to allow for the possibility of early stopping for success or futility. We constructed several alternative designs and studied their operating characteristics via simulation. We then performed virtual re-executions by applying the Bayesian adaptive designs using the OSCAR data to demonstrate the practical applicability of the designs.
Results
We constructed five alternative Bayesian adaptive designs and identified a preferred design based on the simulated operating characteristics, which had similar power to the original design but recruited fewer patients on average. The virtual re-executions showed the Bayesian sequential approach and original OSCAR trial yielded similar trial conclusions. However, using a Bayesian sequential design could have led to a reduced sample size and earlier completion of the trial.
Conclusions
Using the OSCAR trial as an example, this case study found that Bayesian adaptive designs can be constructed for phase III critical care trials. If the OSCAR trial had been run using one of the proposed Bayesian adaptive designs, it would have terminated at a smaller sample size with fewer deaths in the trial, whilst reaching the same conclusions. We recommend the wider use of Bayesian adaptive approaches in phase III clinical trials.
Trial registration
OSCAR Trial registration ISRCTN,
ISRCTN10416500
. Retrospectively registered 13 June 2007.
Journal Article
Autograft or allograft for reconstruction of anterior cruciate ligament: a health economics perspective
Purpose
To assess the clinical and cost-effectiveness of allografts versus autografts in the reconstruction of anterior cruciate ligaments.
Methods
Systematic review of comparative clinical effectiveness and cost-effectiveness analysis.
Results
Both autograft and allograft reconstruction are highly effective. Recent studies show little difference in failure rates between autografts and allografts (about 6% and 7%, respectively). In cost-effectiveness analysis, the price differential is the main factor, making autografts the first choice. However, there will be situations, particularly in revision ACL reconstruction, where an allograft may be preferred, or may be the only reasonable option available.
Conclusion
In ACL reconstruction, clinical results with autografts are as good as or slightly better than with allografts. Allografts cost more, indicating that autografts are more cost-effective and should usually be first choice.
Level of evidence
II.
Journal Article
A patient satisfaction survey investigating pre- and post-operative information provision in lower limb surgery
Background
Planned lower limb surgery is common, with over 90,000 hip replacements, 95,000 knee replacements and 15,000 anterior cruciate ligament reconstructions performed in the UK each year. These procedures are primarily indicated to treat osteoarthritis, sporting injuries and trauma. Patient satisfaction is an important element of healthcare provision, which is usually measured by functional outcomes but influenced by other factors. Few studies have assessed patients’ views on the information given to them pertaining surgery and patients are infrequently consulted when designing leaflets and information packs, which can lead to confusion during the recovery period and poor long-term outcomes. Furthermore, previous studies have not directly asked patients what resources they would prefer, or which format would suit them best. This project aimed to assess if patients were satisfied with the information they received around their operations and to identify potential improvements.
Methods
Set in a National Health Service (NHS) run major trauma centre in the West Midlands, a multiple choice and free-text answer survey was administered to patients who used the orthopaedic service over the course of 1 month. Surveys were designed in Qualtrics and administered face-to-face on paper. Thematic content analysis was performed on the results.
Results
Eighty patients completed the survey, of which 88.8% of patients were satisfied with the information they received. Discussions with surgeons were the most useful resource and 53% of patients requested more internet resources. Post-operative patients were statistically more likely to be dissatisfied with information provision than pre-operative patients. Over 20% of the study population requested more information on post-operative pain and recovery timelines.
Conclusions
Although patients were satisfied in general, areas for change were identified. Suggested resources took the form of webpages and mobile platforms. These resources could contain educational videos, patient experience blogs or interactive recovery timelines, to be of benefit to patients. These suggestions may enable NHS Trusts to “get into the digital age”, however, more research on patient satisfaction around information provision and the impact it has on recovery and decision making is needed.
Journal Article
Item response theory validation of the Oxford knee score and Activity and Participation Questionnaire: a step toward a common metric
The Oxford knee score (OKS) and OKS Activity and Participation Questionnaire (OKS-APQ) are patient-reported outcome measures used to assess people undergoing knee replacement surgery. They have not explicitly been tested for unidimensionality (whether they measure one underlying trait such as ‘knee health’). This study applied item response theory (IRT) to improve the validity of the instruments to optimize for ongoing use.
Participants undergoing primary total knee replacement (TKR) provided preoperative and postoperative responses for OKS and OKS-APQ. Confirmatory factor analysis (CFA) were performed on the OKS and OKS-APQ separately and then on both when pooled into one. An IRT model was fitted to the data.
2972 individual response patterns were analyzed. CFA demonstrated that when combining OKS and OKS-APQ as one instrument, they measure one latent health trait. A user-friendly, free-to-use, web app has been developed to allow clinicians to upload raw data and instantly receive IRT scores.
The OKS and OKS-APQ can be combined to use effectively as a single instrument (producing a single score). For the separate OKS and OKS-APQ the original items and response options can continue to be posed to patients, and this study has confirmed the suitability of IRT-weighted scoring. Applying IRT to existing responses converts traditional sum scores into continuous measurements with greater granularity, including individual measurement error.
•The Oxford knee score and Oxford knee score-Activity and Participation Questionnaire measure one latent trait, coined as ‘knee health’.•Combining scores can potentially overcome floor and ceiling effects.•The presented web app can convert scores from tradition sumscore to item response theory scores.•Item response theory accounts for missing data, existing datasets can retain value.
Journal Article
High tibial osteotomy results in improved frontal plane knee moments, gait patterns and patient-reported outcomes
Purpose
The purpose of this study was to quantify changes in knee loading in the three clinical planes, compensatory gait adaptations and patient-reported outcome measures (PROMS) resulting from opening wedge high tibial osteotomy (HTO).
Methods
Gait analysis was performed on 18 participants (19 knees) with medial osteoarthritis (OA) and varus alignment pre- and post-HTO, along with 18 controls, to calculate temporal, kinematic and kinetic measures. Oxford Knee Score, Knee Outcome Survey and visual analogue pain scores were collected. Paired and independent sample tests identified changes following surgery and deviations from controls.
Results
HTO restored frontal and transverse plane knee joint loading to that of the control group, while reductions remained in the sagittal plane. Elevated frontal plane trunk sway (
p
= 0.031) and reduced gait speed (
p
= 0.042), adopted as compensatory gait changes pre-HTO, were corrected by the surgery. PROMs significantly improved (
p
≤ 0.002). Centre of pressure (COP) was lateralised relative to the knee post-HTO (
p
< 0.001). Energy absorbed in the sagittal plane significantly increased post-HTO (
p
= 0.007), whilst work done in the transverse plane reduced (
p
≤ 0.008). Pre-operative gait deviations from the control group that were retained post-HTO included smaller sagittal (
p
= 0.003) knee range of motion during gait, greater stance duration (
p
= 0.008) and altered COP location (anterior to the knee) in early stance (
p
= 0.025).
Conclusions
HTO surgery restored frontal and transverse plane knee loading to normal levels and improved PROMs. Gait adaptations known to reduce knee loading employed pre-HTO were not retained post-HTO. Some gait features were found to differ between post-HTO subjects and controls.
Level of evidence
II
Journal Article