Type-II error rates (beta errors) of randomized trials in orthopaedic trauma

Teaching Science to the Next Generation

Teaching science to the next generation begins with foundations laid in podiatric medical school. Interest and immersion in research continues to develop through residency as trainees prepare for cases, participate in journal clubs, present posters and articles, and attend conferences. Having adequate training is essential to production of quality research. Although challenges and barriers exist, numerous resources are available at all levels of practice to guide those who are interested in contributing to the body of literature that supports the profession. Ensuring a robust pipeline of future clinician scientists is critical to the future of the profession.

Can propensity score matching replace randomized controlled trials?

Randomized controlled trials (RCTs) have long been recognized as the gold standard for establishing causal relationships in clinical research. Despite that, various limitations of RCTs prevent its widespread implementation, ranging from the ethicality of withholding potentially-lifesaving treatment from a group to relatively poor external validity due to stringent inclusion criteria, amongst others. However, with the introduction of propensity score matching (PSM) as a retrospective statistical tool, new frontiers in establishing causation in clinical research were opened up. PSM predicts treatment effects using observational data from existing sources such as registries or electronic health records, to create a matched sample of participants who received or did not receive the intervention based on their propensity scores, which takes into account characteristics such as age, gender and comorbidities. Given its retrospective nature and its use of observational data from existing sources, PSM circumvents the aforementioned ethical issues faced by RCTs. Majority of RCTs exclude elderly, pregnant women and young children; thus, evidence of therapy efficacy is rarely proven by robust clinical research for this population. On the other hand, by matching study patient characteristics to that of the population of interest, including the elderly, pregnant women and young children, PSM allows for generalization of results to the wider population and hence greatly increases the external validity. Instead of replacing RCTs with PSM, the synergistic integration of PSM into RCTs stands to provide better research outcomes with both methods complementing each other. For example, in an RCT investigating the impact of mannitol on outcomes among participants of the Intensive Blood Pressure Reduction in Acute Cerebral Hemorrhage Trial, the baseline characteristics of comorbidities and current medications between treatment and control arms were significantly different despite the randomization protocol. Therefore, PSM was incorporated in its analysis to create samples from the treatment and control arms that were matched in terms of these baseline characteristics, thus providing a fairer comparison for the impact of mannitol. This literature review reports the applications, advantages, and considerations of using PSM with RCTs, illustrating its utility in refining randomization, improving external validity, and accounting for non-compliance to protocol. Future research should consider integrating the use of PSM in RCTs to better generalize outcomes to target populations for clinical practice and thereby benefit a wider range of patients, while maintaining the robustness of randomization offered by RCTs.

Pro-Con Debate: Interdisciplinary Perspectives on Industry-Sponsored Research

Pro: Nearly all new devices and drugs come from industry that provides two-thirds of the funding for medical research, and a much higher fraction of clinical research. Realistically, without corporate-funded studies, perioperative research would stagnate with little innovation and few new products. Opinions are ubiquitous and normal, but do not constitute epidemiologic bias. Competent clinical research includes many protections against selection and measurement bias, and the publication process provides at least moderate protection against misinterpretation of results. Trial registries largely prevent selective data presentation. Sponsored trials are particularly protected against inappropriate corporate influence because they are usually codesigned with the US Food and Drug Administration, and analyses are based on formal predefined statistical plans, as well as being conducted with rigorous external monitoring. Novel products, which are essential for advances in clinical care, largely come from industry, and industry appropriately funds much of the required research. We should celebrate industry's contribution to improvements in clinical care. Con: While industry funding contributes to research and discovery, examples of industry-funded research demonstrate bias. In the setting of financial pressures and potential conflict of interest, bias can influence the type of study design, hypotheses being tested, rigor and transparency in data analysis, interpretation, as well as reporting of the results. Unlike public granting agencies, industry does not necessarily provide funding based on unbiased peer review following an open call for proposals. The focus on success can influence the choice of a comparator, which might not be ideal among the possible alternatives, the language used in the publication, and even the ability to publish. Unpublished negative trials can result in selected information being withheld from the scientific community and the public. Appropriate safeguards are needed to ensure that research addresses the most important and relevant questions, that results are available even when they do not support the use of a product produced by the funding company, that populations studied reflect the relevant patients, that the most rigorous approaches are applied, that studies have the appropriate power to address the question posed, and that conclusions are presented in an unbiased manner.

Pro-Con Debate: Interdisciplinary Perspectives on Industry-Sponsored Research

PRO: Nearly all new devices and drugs come from industry that provides two-thirds of the funding for medical research, and a much higher fraction of clinical research. Realistically, without corporate-funded studies, perioperative research would stagnate with little innovation and few new products. Opinions are ubiquitous and normal but do not constitute epidemiologic bias. Competent clinical research includes many protections against selection and measurement bias, and the publication process provides at least moderate protection against misinterpretation of results. Trial registries largely prevent selective data presentation. Sponsored trials are particularly protected against inappropriate corporate influence because they are usually codesigned with the US Food and Drug Administration, and analyses are based on formal predefined statistical plans, as well as being conducted with rigorous external monitoring. Novel products, which are essential for advances in clinical care, largely come from industry, and industry appropriately funds much of the required research. We should celebrate industry's contribution to improvements in clinical care. CON: While industry funding contributes to research and discovery, examples of industry-funded research demonstrate bias. In the setting of financial pressures and potential conflict of interest, bias can influence the type of study design, hypotheses being tested, rigor and transparency in data analysis, interpretation, as well as reporting of the results. Unlike public granting agencies, industry does not necessarily provide funding based on unbiased peer review following an open call for proposals. The focus on success can influence the choice of a comparator, which might not be ideal among the possible alternatives, the language used in the publication, and even the ability to publish. Unpublished negative trials can result in selected information being withheld from the scientific community and the public. Appropriate safeguards are needed to ensure that research addresses the most important and relevant questions, that results are available even when they do not support the use of a product produced by the funding company, that populations studied reflect the relevant patients, that the most rigorous approaches are applied, that studies have the appropriate power to address the question posed, and that conclusions are presented in an unbiased manner.

Current Trends in Orthobiologics: An 11-Year Review of the Orthopaedic Literature

BACKGROUND

The use of "orthobiologics" or regenerative therapies in orthopaedic surgery has grown in recent years. Particular interest has been raised with regard to platelet-rich plasma, bone marrow aspirate, adipose-derived cells, and amniotic cells. Although studies have analyzed outcomes after orthobiologic treatment, no study has analyzed how the literature as a whole has evolved.

PURPOSE

To evaluate trends in platelet-rich plasma, bone marrow aspirate, adipose-derived cells, and amniotic cell publications and to assess how these might inform efforts to establish minimum reporting standards and forecast future use.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A database was compiled systematically using PubMed to identify articles published between 2009 and 2019 within 9 prominent orthopaedic journals and pertaining to the use of platelet-rich plasma, bone marrow aspirate, adipose-derived cells, and amniotic cells in the treatment of musculoskeletal conditions. Included articles were classified as clinical, nonclinical (translational or basic science), or review, and a variety of study parameters were recorded for each. Additional queries were performed to identify articles that utilized minimum reporting standards.

RESULTS

A total of 474 articles (132 clinical, 271 nonclinical, 71 review) were included, consisting of 244 (51.5%) platelet-rich plasma, 146 (30.8%) bone marrow aspirate, 72 (15.2%) adipose-derived cells, and 12 (2.5%) amniotic cells. The greatest annual increase in publications for each orthobiologic topic was from 2018 to 2019. The American Journal of Sports Medicine demonstrated the highest number of overall (34.2%) and clinical (50.0%) publications, and accounted for 44.3% of all platelet-rich plasma publications. The Journal of Orthopaedic Research accounted for the second highest overall number of publications (24.9%) and highest nonclinical publications (41.0%). Platelet-rich plasma accounted for 91.5% of all level 1 clinical studies, while much greater than half of bone marrow aspirate, adipose-derived cells, and amniotic cell publications were level 3 or lower. Out of the 207 articles that used some form of reporting protocol, 59 (28.5%) used an established algorithm and 125 (60.4%) used their own.

CONCLUSION

Interest in orthobiologics continues to grow, as evidenced by an increasing trend in publications over an 11-year period. However, current reporting on orthobiologic formulations is largely heterogeneous, emphasizing the need for minimum reporting standards and higher-quality studies.

Methodological aspects of a randomized within-patient concurrent controlled design for clinical trials in spine surgery

INTRODUCTION

Randomized controlled trials are considered the highest level of evidence, but their feasibility in the surgical field is severely hampered by methodological and practical issues. Concurrent comparison between the experimental and control conditions within the same patient can be an effective strategy to mitigate some of these challenges and improve generalizability, mainly by the elimination of between-patient variability and reduction of the required sample size. This article aims (1) to describe the methodological aspects of a randomized within-patient controlled trial and (2) to quantify the added value of this design, based on a recently completed randomized within-patient controlled trial on bone grafts in instrumented lumbar posterolateral spinal fusion.

METHODS

Boundary conditions for the application of the randomized within-patient controlled trial design were identified. Between-patient variability was quantified by the intraclass correlation coefficient and concordance in the primary fusion outcome. Sample size, study duration and costs were compared with a classic randomized controlled trial design.

RESULTS

Boundary conditions include the concurrent application of the experimental and control conditions to identical but physically separated sites. Moreover, the outcome of interest should be local, uncorrelated and independently assessable. The spinal fusion outcomes within a patient were found to be more similar than between different patients (intraclass correlation coefficient 32% and concordance 64%), demonstrating a clear effect of patient-related factors. The randomized within-patient controlled trial design allowed a reduction of the sample size to one-third of a parallel-group randomized controlled trial, thereby halving the trial duration and costs.

CONCLUSION

When suitable, the randomized within-patient controlled trial is an efficient design that provides a solution to some of the considerable challenges of a classic randomized controlled trial in (spine) surgery. This design holds specific promise for efficacy studies of non-active bone grafts in instrumented posterolateral fusion surgery.

Common errors in the design of orthopaedic trials: Has anything changed?

INTRODUCTION

The adoption of evidence-based orthopaedics has shifted the focus from expert base opinions and anecdotal evidence to a focus on integrating the best available clinical research. This shift has led to an increased focus on randomized controlled trials (RCTs) within the field. Although RCTs are considered the highest level of evidence, methodologic errors can introduce bias and limit the validity of the results. Early trials were hampered by lack of blinding, inadequate sample sizes and other design flaws. The objective of this review was to examine the current literature to determine if the design and execution of RCTs has improved.

DESIGN ERRORS

The awareness of the importance of sample size increased over time with substantially more trials reporting sample size calculations. However, many contemporary RCTs are still underpowered and fail to reach their calculated sample size. Given the challenges of surgically based RCTs, the majority of historical trials lacked blinding, increasing the risk of bias. There is evidence that there has been a concerted effort to increase the blinding in RCTs, particularly in outcome assessors. A more recent development in the design of surgical trials is the introduction of expertise-based trial designs in which patients are randomized to a surgeon with expertise in a particular intervention. These trials minimize the bias that can arise from differential expertise bias and have the potential to improve the validity and feasibility of RCTs. Finally, there has been an increased focus on the reporting of patient reported outcomes (PROs) in orthopaedic RCTs. Alongside this movement has been the development of minimal important differences (MIDs) to define the changes that are relevant and meaningful to patients. Both PROs and MIDs should be taken into consideration when calculating the sample size and study power in clinical trials.

CONCLUSIONS

Although marked improvements have been made in the design and implementation of trials, there is still considerable room for improvement. Adequately blinded and powered studies evaluating clinically important outcomes and differences should be key considerations in trial design moving forward.

Herausforderungen von Evidenzlevel-1-Studien in der Unfallchirurgie und Orthopädie

Randomisierte kontrollierte klinische Studien stellen für chirurgische Fachdisziplinen eine Herausforderung dar. Dieser Artikel beschreibt die Besonderheiten und Schwierigkeiten solcher Studien. Wann immer möglich, sollte das höchste Evidenzlevel angestrebt werden. Ist ein hohes Evidenzlevel allerdings methodisch nicht korrekt erreichbar, sollte das bestmögliche nächste Evidenzlevel erzielt werden. Die Bewertung, auch im Hinblick auf die Kostenerstattung, sollte daher gerade in chirurgischen Disziplinen nicht ausschließlich am Evidenzlevel festgemacht werden. Vielmehr sollte im Rahmen von Expertengremien und unter Zuhilfenahme der besten, verfügbaren Evidenz beurteilt werden.

The Blight of the Type II Error: When No Difference Does Not Mean No Difference

Much focus in research has been given to minimizing type I errors, where we incorrectly conclude that there is a difference between 2 treatments or populations. In contrast, our standard scientific method and power analysis allows for a much greater rate of type II errors, in which we fail to show a difference when, in fact, one exists (≥20% rate of type II errors vs ≤5% rate of type I errors). Additional factors that can cause type II errors may propel their prevalence to well in excess of 20%. Failure to reject the null hypothesis may be a tolerable outcome in a certain proportion of studies. However, type II errors may become dangerous when the conclusions of a study overreach, incorrectly stating that there is no difference, when, in fact, a difference exists. Type II errors resulting in overreaching conclusions may impede incremental advances in our field, as the advantages of small improvements may go undetected. To avert this danger in studies that fail to meet statistical significance, we as researchers (20% or more, vs 5% for type I errors) be precise in our conclusions stating simply that the null hypothesis could not be rejected.

Surgical or non-surgical treatment of traumatic skeletal fractures in adults: systematic review and meta-analysis of benefits and harms

BACKGROUND

A comprehensive overview of treatments of common fractures is missing, although it would be important for shared decision-making in clinical practice. The aim was to determine benefits and harms of surgical compared to non-surgical treatments for traumatic skeletal fractures.

METHODS

We searched Medline, Embase, CINAHL, Web of Science, and CENTRAL until November 2018, for randomized trials of surgical treatment in comparison with or in addition to non-surgical treatment of fractures in adults. For harms, only trials with patient enrollment in 2000 or later were included, while no time restriction was applied to benefits. Two reviewers independently assessed studies for inclusion, extracted data from full-text trials, and performed risk of bias assessment. Outcomes were self-reported pain, function, and quality of life, and serious adverse events (SAEs). Random effects model (Hedges' g) was used.

RESULTS

Out of 28375 records screened, we included 61 trials and performed meta-analysis on 12 fracture types in 11 sites: calcaneus, clavicula, femur, humerus, malleolus, metacarpus, metatarsus, radius, rib, scaphoideum, and thoraco-lumbar spine. Seven other fracture types only had one trial available. For distal radius fractures, the standardized mean difference (SMD) was 0.31 (95% CI 0.10 to 0.53, n = 378 participants) for function, favoring surgery, however, with greater risk of SAEs (RR = 3.10 (1.42 to 6.77), n = 436). For displaced intra-articular calcaneus fractures, SMD was 0.64 (0.13 to 1.16) for function (n = 244) and 0.19 (0.01 to 0.36) for quality of life (n = 506) favoring surgery. Surgery was associated with a smaller risk of SAE than non-surgical treatment for displaced midshaft clavicular fractures (RR = 0.62 (0.42 to 0.92), n = 1394). None of the other comparisons showed statistical significance differences and insufficient data existed for most of the common fracture types.

CONCLUSIONS

Of 12 fracture types with more than one trial, only two demonstrated a difference in favor of surgery (distal radius fractures and displaced intra-articular calcaneus fractures), one of which demonstrated a greater risk of harms in the surgical group (distal radius fractures). Our results highlight the current paucity of high-quality randomized trials for common fracture types and a considerable heterogeneity and risk of bias in several of the available trials.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42015020805.

Preemptive Pregabalin in Children and Adolescents Undergoing Posterior Instrumented Spinal Fusion: A Double-Blinded, Placebo-Controlled, Randomized Clinical Trial

BACKGROUND

Pregabalin as part of a multimodal pain-management regimen has been shown to reduce opioid consumption after spinal surgery in adults but it is unclear whether this is also true in adolescents. Pregabalin has been found to have neuroprotective effects and therefore could have a positive impact on pain after spinal deformity surgery. We conducted a randomized, double-blinded, placebo-controlled clinical trial of adolescent patients undergoing spinal fusion to evaluate the short-term effects of pregabalin on postoperative pain and opioid consumption.

METHODS

Adolescents with adolescent idiopathic scoliosis, Scheuermann kyphosis, or spondylolisthesis who were scheduled for posterior spinal fusion with all-pedicle-screw instrumentation were randomized to receive either pregabalin (2 mg/kg twice daily) or placebo preoperatively and for 5 days after surgery. The patients ranged from 10 to 21 years of age. The primary outcome was total opioid consumption as measured with use of patient-controlled analgesia. Postoperative pain scores and opioid-related adverse effects were evaluated.

RESULTS

Sixty-three of 77 eligible patients were included and analyzed. Cumulative oxycodone consumption per kilogram did not differ between the study groups during the first 48 hours postoperatively, with a median of 1.44 mg/kg (95% confidence interval [CI],1.32 to 1.67 mg/kg) in the pregabalin group and 1.50 mg/kg (95% CI, 1.39 to 1.79 mg/kg) in the placebo group (p = 0.433). A subgroup analysis of 51 patients with adolescent idiopathic scoliosis showed the same result, with a mean of 1.45 mg/kg (95% CI, 1.24 to 1.65 mg/kg) in the pregabalin group and 1.59 mg/kg (95% CI, 1.37 to 1.82 mg/kg) in the placebo group (p = 0.289). Total oxycodone consumption per hour (mg/kg/hr) was not different between the groups over the time points (p = 0.752). The postoperative pain scores did not differ significantly between the groups (p = 0.196).

CONCLUSIONS

The use of perioperative pregabalin does not reduce the postoperative opioid consumption or pain scores in adolescents after posterior spinal fusion surgery.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Are large clinical trials in orthopaedic trauma justified?

BACKGROUND

The objective of this analysis is to evaluate the necessity of large clinical trials using FLOW trial data.

METHODS

The FLOW pilot study and definitive trial were factorial trials evaluating the effect of different irrigation solutions and pressures on re-operation. To explore treatment effects over time, we analyzed data from the pilot and definitive trial in increments of 250 patients until the final sample size of 2447 patients was reached. At each increment we calculated the relative risk (RR) and associated 95% confidence interval (CI) for the treatment effect, and compared the results that would have been reported at the smaller enrolments with those seen in the final, adequately powered study.

RESULTS

The pilot study analysis of 89 patients and initial incremental enrolments in the FLOW definitive trial favored low pressure compared to high pressure (RR: 1.50, 95% CI: 0.75-3.04; RR: 1.39, 95% CI: 0.60-3.23, respectively), which is in contradiction to the final enrolment, which found no difference between high and low pressure (RR: 1.04, 95% CI: 0.81-1.33). In the soap versus saline comparison, the FLOW pilot study suggested that re-operation rate was similar in both the soap and saline groups (RR: 0.98, 95% CI: 0.50-1.92), whereas the FLOW definitive trial found that the re-operation rate was higher in the soap treatment arm (RR: 1.28, 95% CI: 1.04-1.57).

CONCLUSIONS

Our findings suggest that studies with smaller sample sizes would have led to erroneous conclusions in the management of open fracture wounds.

TRIAL REGISTRATION

NCT01069315 (FLOW Pilot Study) Date of Registration: February 17, 2010, NCT00788398 (FLOW Definitive Trial) Date of Registration: November 10, 2008.

Sample size of surgical randomized controlled trials: a lack of improvement over time

BACKGROUND

Interpretation of randomized controlled trials (RCTs) without a significant difference regarding the primary outcome (negative RCTs) is frequently challenging, due to concerns about sample size and thus sufficient statistical power. We aimed to assess the adequacy of sample size and corresponding power of surgical RCTs.

METHODS

We previously identified all surgical RCTs available in PubMed in two distinct years a decade apart (1999 and 2009). For all "negative" trials, we estimated whether the sample size of the trial was appropriate to detect a difference in the primary outcome measure. The main outcome measure was a sufficient sample size to detect large, medium, and small treatment effects. We also performed a post hoc power analysis based on the actual observed effect difference.

RESULTS

A total of 228 negative RCTs (74 in 1999 and 121 in 2009) were included. The median sample size was 76 (± 222) and 80 (± 163) in 1999 and 2009, respectively. Sample size calculation was increasingly reported from 40% in 1999 to 54% in 2009 (P = 0.02). The proportion of studies adequately powered to detect large (57% versus 68%), medium (26% versus 25%), or small (8% versus 7%) differences did not differ significantly between 1999 and 2009, respectively. To reach sufficient power, the required increases in sample size were 130%, 240%, and 1032% for large, medium, and small differences, respectively. Reporting a sample size calculation was the only independent predictor for adequate power.

CONCLUSIONS

Despite slight improvement in the reporting of a sample size calculation, about a third of surgical trials remains underpowered to demonstrate differences that are likely to be clinically significant. Increased attention of researchers, medical ethical boards, and journal editors is required to reduce potentially wasted resources on underpowered trials.

Accessibility, accountability, affordability: healthcare policy in orthopedic trauma

PURPOSE OF REVIEW

This review provides historical background on trauma care in the USA and summarizes contemporary trauma-related health policy issues. It is a primer for orthopedic surgeons who want to promote improvements in research, delivery, and cost reduction in trauma care.

RECENT FINDINGS

As of 2010, funding for trauma research accounted for only 0.02% of all National Institutes of Health research funding. This is disproportionate to the societal burden of traumatic injury, which is the leading cause of death and disability among people aged 1 to 46 years in the USA. The diagnosis-related group model of hospital reimbursement penalizes level-I trauma centers, which typically treat the most severely injured patients. Treatment of traumatic injury at level-I and level-II trauma centers is associated with lower rates of major complications and death compared with treatment at non-trauma centers. Patient proximity to trauma centers has been positively correlated with survival after traumatic injury. Inadequate funding has been cited as a reason for recent closures of trauma centers. Orthopedic surgeons have a responsibility to engage in efforts to improve the quality, accessibility, and affordability of trauma care. This can be done by advocating for greater funding for trauma research; choosing the most cost-effective, patient-appropriate orthopedic implants; supporting the implementation of a national trauma system; leading high-quality research of trauma patient outcomes; and advocating for greater accessibility to level-I trauma centers for underserved populations.

The quality of randomised controlled trials involving surgery from the hand to the elbow

Aims

Our purpose was to determine the quality of current randomised controlled trials (RCTs) in hand surgery using standardised metrics.

Materials and Methods

Based on five-year mean impact factors, we selected the six journals that routinely publish studies of upper extremity surgery. Using a journal-specific search query, 62 RCTs met our inclusion criteria. Then three blinded reviewers used the Jadad and revised Coleman Methodology Score (RCMS) to assess the quality of the manuscripts.

Results

Based on the Jadad scale, 28 studies were of high quality and 34 were of low quality. Methodological deficiencies in poorly scoring trials included the absence of rate of enrolment, no power analysis, no description of withdrawal or dropout, and a failure to use validated outcomes assessments with an independent investigator.

Conclusion

A large number of RCTs in hand, wrist, and elbow surgery were of suboptimal quality when judged against the RCMS and Jadad scales. Even with a high level of evidence, study design and execution of RCTs should be critically assessed. Methodological deficiencies may introduce bias and lead to statistically underpowered studies. Cite this article: Bone Joint J 2017;99-B:94–9.

Experimental toxicology: Issues of statistics, experimental design, and replication

The difficulty of replicating experiments has drawn considerable attention. Issues with replication occur for a variety of reasons ranging from experimental design to laboratory errors to inappropriate statistical analysis. Here we review a variety of guidelines for statistical analysis, design, and execution of experiments in toxicology. In general, replication can be improved by using hypothesis driven experiments with adequate sample sizes, randomization, and blind data collection techniques.

Comparison of soft tissue balancing, femoral component rotation, and joint line change between the gap balancing and measured resection techniques in primary total knee arthroplasty: A meta-analysis

BACKGROUND

This meta-analysis was designed to compare the accuracy of soft tissue balancing and femoral component rotation as well as change in joint line positions, between the measured resection and gap balancing techniques in primary total knee arthroplasty.

METHODS

Studies were included in the meta-analysis if they compared soft tissue balancing and/or radiologic outcomes in patients who underwent total knee arthroplasty with the gap balancing and measured resection techniques. Comparisons included differences in flexion/extension, medial/lateral flexion, and medial/lateral extension gaps (LEGs), femoral component rotation, and change in joint line positions. Finally, 8 studies identified via electronic (MEDLINE, EMBASE, and the Cochrane Library) and manual searches were included. All 8 studies showed a low risk of selection bias and provided detailed demographic data. There was some inherent heterogeneity due to uncontrolled bias, because all included studies were observational comparison studies.

RESULTS

The pooled mean difference in gap differences between the gap balancing and measured resection techniques did not differ significantly (-0.09 mm, 95% confidence interval [CI]: -0.40 to +0.21 mm; P = 0.55), except that the medial/LEG difference was 0.58 mm greater for measured resection than gap balancing (95% CI: -1.01 to -0.15 mm; P = 0.008). Conversely, the pooled mean difference in femoral component external rotation (0.77°, 95% CI: 0.18° to 1.35°; P = 0.01) and joint line change (1.17 mm, 95% CI: 0.82 to 1.52 mm; P < 0.001) were significantly greater for the gap balancing than the measured resection technique.

CONCLUSION

The gap balancing and measured resection techniques showed similar soft tissue balancing, except for medial/LEG difference. However, the femoral component was more externally rotated and the joint line was more elevated with gap balancing than measured resection. These differences were minimal (around 1 mm or 1°) and therefore may have little effect on the biomechanics of the knee joint. This suggests that the gap balancing and measured resection techniques are not mutually exclusive.

Design and Validity of Randomized Controlled Dental Restorative Trials

Background: The evidence stemming from trials on restorative materials is shaped not only by trial findings, but also trial design and validity. We aimed to evaluate both aspects in randomized controlled dental restorative trials published from 2005-2015. Methods: Using systematic review methodology, we retrieved trials comparing restorative or adhesive dental materials. Two authors independently assessed design, risk of bias, registration status, and findings of trials. Descriptive and regression analyses were performed. Results: 114 studies on 15,321 restorations placed mainly in permanent teeth of 5232 patients were included. Per trial, the median number of patients was 37 (25th/75th percentiles: 30/51). Follow-up was 24 (20/48) months. Seventeen percent of trials reported on sample size calculations, 2% had been registered. Most trials (90%) used US Public Health Service (USPHS) criteria, and had a high risk of bias. More recent trials were more likely to have been registered, to have reported on sample size calculations, to be of low risk of bias, and to use other than USPHS-criteria. Twenty-three percent of trials yielded significant differences between groups. The likelihood of such differences was significantly increased in older studies, studies with potential reporting bias, published in journals with high impact factor (>2), longer follow-up periods, and not using USPHS-criteria. Conclusions: The majority of dental restorative trials published from 2005-2015 had limited validity. Risk of bias decreased in more recent trials. Future trials should aim for high validity, be registered, and use defined and appropriate sample sizes, follow-up periods, and outcome measures.

Locking intramedullary nails compared with locking plates for two- and three-part proximal humeral surgical neck fractures: a randomized controlled trial

BACKGROUND

Previous studies have shown good clinical results in patients with proximal humeral fractures (PHFs) treated with locking intramedullary nails or locking plates. Our study compared the clinical and radiographic outcomes in patients with 2- and 3-part surgical neck fractures.

METHODS

In this prospective, randomized controlled trial, 72 patients with 2- or 3-part surgical neck PHFs were randomly assigned to receive fixation with locking intramedullary nails (nail group) or locking plates (plate group). The primary outcome was the 12-month Constant-Murley score. The secondary outcomes included the Disabilities of the Arm, Shoulder and Hand score, the visual analog scale pain score, the shoulder passive range of motion, the neck-shaft angle, and complication rates.

RESULTS

There was no significant mean treatment group difference in the Constant-Murley score at 12 months (70.3 points for the nail group vs. 71.5 points for the plate group; P = .750) or at individual follow-up assessments. There were no differences in the 3-, 6- and 12-month Disabilities of the Arm, Shoulder and Hand scores, visual analog scale scores, and range of motion, except for the medial rotation at 6 months. The neck-shaft angle was equivalent between the groups at 12 months. There were significant differences over 12 months in total complication rates (P = .002) and reoperation rates (P = .041). There were no significant differences for the rotator cuff tear rate (P = .672).

CONCLUSION

Fixation of PHFs with locking plates or locking intramedullary nails produces similar clinical and radiologic results. Nevertheless, the complication and reoperation rates were higher in the nail group.

RANDOMIZED CONTROLLED CLINICAL TRIALS IN ORTHOPEDICS: DIFFICULTIES AND LIMITATIONS

Randomized controlled clinical trials (RCTs) are considered to be the gold standard for evidence-based medicine nowadays, and are important for directing medical practice through consistent scientific observations. Steps such as patient selection, randomization and blinding are fundamental for conducting a RCT, but some additional difficulties are presented in trials that involve surgical procedures, as is common in orthopedics. The aim of this article was to highlight and discuss some difficulties and possible limitations on RCTs within the field of surgery.

Biopsy vs. extensive resection for first recurrence of glioblastoma: is a prospective clinical trial warranted?

BACKGROUND

Glioblastoma is an aggressive and almost universally fatal tumor. The prognosis at the time of recurrence has generally been poor, with overall survival typically in the range of 4-40 weeks. The merits of surgical resection (vs. open biopsy, to confirm recurrence via histology) in addition to conventional adjuvant chemotherapy have been the subject of longstanding debate. We wondered whether it would possible to conduct a trial at our institution to settle this question definitively with Class I evidence.

RESULTS

Initially, we had hoped to conduct a randomized, unblinded prospective clinical trial. However on closer inspection it appeared that such an undertaking would pose significant practical challenges. Thus we present our protocol in draft form. In keeping with recommended outcomes for these tumors, the primary endpoint would be median progression free survival. Secondary end points would be: median overall survival (mOS, from time of recurrence) and change in Karnofsky Performance Status over time. Patients would be eligible at the time of first recurrence if they had received conventional treatment until that point and at least 1 month had elapsed since the time of radiation. All patients would be considered potentially eligible for enrollment (unless the decision regarding resection was already clear-cut in view of other factors). Using Cox's proportional hazards model, we estimate that at least 456 patients would be necessary to demonstrate an increase in the hazard ratio to 1.3 for those undergoing biopsy alone. This magnitude of benefit is estimated based on a review of retrospective studies.

DISCUSSION

If restricted to our Institution alone, which sees approximately 100-150 new cases of glioblastoma each year, a trial of this nature would be likely to take around 10 years. Furthermore, there may be significant reluctance on the part of patients and physicians to participate. There is also the opportunity cost of excluding patients from other trials to consider. We recognize that the estimate of the magnitude of effect may be conservative. As things stand, we feel that multi-institutional collaboration would almost certainly be required for an undertaking of this kind.

In-hospital mortality from femoral shaft fracture depends on the initial delay to fracture fixation and Injury Severity Score: a retrospective cohort study from the NTDB 2002-2006

BACKGROUND

Optimal surgical timing for definitive treatment of femur fractures in severely injured patients remains controversial. This study was performed to examine in-hospital mortality for patients with femur fractures with regard to surgical timing, Injury Severity Score (ISS), and age.

METHODS

The National Trauma Data Bank version 7.0 was used to evaluate in-hospital mortality for patients presenting with unilateral femur fractures. Patients were stratified into four groups by surgical timing (ST) and four groups by ISS. χ tests were used to evaluate baseline interrelationships. Binary regression was used to examine the association between time to surgery, ISS score, age, and mortality after adjusting for patient medical comorbidities, and personal demographics.

RESULTS

A total of 7,540 patients met inclusion criteria, with a 1.4% overall in-hospital mortality rate. For patients with an isolated femur fracture, surgical delay beyond 48 hours was associated with nearly five times greater mortality risk compared with surgery within 12 hours (adjusted relative risk, 4.8; 95% confidence interval, 1.6-14.1). Only severely injured patients (ISS, 26+) had higher associated mortality with no delay in surgical fixation (ST1 < 12 hours) relative to ST2 of 13 hours to 24 hours with an adjusted relative risk of 4.2 (95% confidence interval, 1.0-16.7). The association between higher mortality rates and surgical delay beyond 48 hours was even stronger in the elderly patients.

CONCLUSION

This study supports the work of previous authors who reported that early definitive fixation of femur fractures is not only beneficial, particularly in the elderly, but also consistent with more recent studies recommending at least 12-hour to 24-hour delay in fixation in severely injured patients to promote better resuscitation.

LEVEL OF EVIDENCE

Therapeutic study, level III.

Randomised trial support for orthopaedic surgical procedures

We investigated the proportion of orthopaedic procedures supported by evidence from randomised controlled trials comparing operative procedures to a non-operative alternative. Orthopaedic procedures conducted in 2009, 2010 and 2011 across three metropolitan teaching hospitals were identified, grouped and ranked according to frequency. Searches of the Cochrane Central Register of Controlled Trials (CENTRAL), the Cochrane Database of Systematic Reviews (CDSR) and the Database of Abstracts of Reviews of Effects (DARE) were performed to identify RCTs evaluating the most commonly performed orthopaedic procedures. Included studies were categorised as "supportive" or "not supportive" of operative treatment. A risk of bias analysis was conducted for included studies using the Cochrane Collaboration's Risk of Bias tool. A total of 9,392 orthopaedic procedures were performed across the index period. 94.6% (8886 procedures) of the total volume, representing the 32 most common operative procedure categories, were used for this analysis. Of the 83 included RCTs, 22.9% (19/83) were classified as supportive of operative intervention. 36.9% (3279/8886) of the total volume of procedures performed were supported by at least one RCT showing surgery to be superior to a non-operative alternative. 19.6% (1743/8886) of the total volume of procedures performed were supported by at least one low risk of bias RCT showing surgery to be superior to a non-operative alternative. The level of RCT support for common orthopaedic procedures compares unfavourably with other fields of medicine.

(Sample) size matters! An examination of sample size from the SPRINT trial study to prospectively evaluate reamed intramedullary nails in patients with tibial fractures

INTRODUCTION

Inadequate sample size and power in randomized trials can result in misleading findings. This study demonstrates the effect of sample size in a large clinical trial by evaluating the results of the Study to Prospectively evaluate Reamed Intramedullary Nails in Patients with Tibial fractures (SPRINT) trial as it progressed.

METHODS

The SPRINT trial evaluated reamed versus unreamed nailing of the tibia in 1226 patients, and in open and closed fracture subgroups (N = 400 and N = 826, respectively). We analyzed the reoperation rates and relative risk comparing treatment groups at 50, 100, and then increments of 100 patients up to the final sample size. Results at various enrollments were compared with the final SPRINT findings.

RESULTS

In the final analysis, there was a statistically significant decreased risk of reoperation with reamed nails for closed fractures (relative risk reduction 35%). Results for the first 35 patients enrolled suggested that reamed nails increased the risk of reoperation in closed fractures by 165%. Only after 543 patients with closed fractures were enrolled did the results reflect the final advantage for reamed nails in this subgroup. Similarly, the trend toward an increased risk of reoperation for open fractures (23%) was not seen until 62 patients with open fractures were enrolled.

CONCLUSIONS

Our findings highlight the risk of conducting a trial with insufficient sample size and power. Such studies are not only at risk of missing true effects but also of giving misleading results.

SPIRIT 2013 explanation and elaboration: guidance for protocols of clinical trials

High quality protocols facilitate proper conduct, reporting, and external review of clinical trials. However, the completeness of trial protocols is often inadequate. To help improve the content and quality of protocols, an international group of stakeholders developed the SPIRIT 2013 Statement (Standard Protocol Items: Recommendations for Interventional Trials). The SPIRIT Statement provides guidance in the form of a checklist of recommended items to include in a clinical trial protocol. This SPIRIT 2013 Explanation and Elaboration paper provides important information to promote full understanding of the checklist recommendations. For each checklist item, we provide a rationale and detailed description; a model example from an actual protocol; and relevant references supporting its importance. We strongly recommend that this explanatory paper be used in conjunction with the SPIRIT Statement. A website of resources is also available (www.spirit-statement.org). The SPIRIT 2013 Explanation and Elaboration paper, together with the Statement, should help with the drafting of trial protocols. Complete documentation of key trial elements can facilitate transparency and protocol review for the benefit of all stakeholders.

Advances and future directions for management of trauma patients with musculoskeletal injuries

Musculoskeletal injuries are the most common reason for operative procedures in severely injured patients and are major determinants of functional outcomes. In this paper, we summarise advances and future directions for management of multiply injured patients with major musculoskeletal trauma. Improved understanding of fracture healing has created new possibilities for management of particularly challenging problems, such as delayed union and non union of fractures and large bone defects. Optimum timing of major orthopaedic interventions is guided by increased knowledge about the immune response after injury. Individual treatment should be guided by trading off the benefits of early definitive skeletal stabilisation, and the potentially life-threatening risks of systemic complications such as fat embolism, acute lung injury, and multiple organ failure. New methods for measurement of fracture healing and function and quality of life outcomes pave the way for landmark trials that will guide the future management of musculoskeletal injuries.

Reaching consensus on the physiotherapeutic management of patients following upper abdominal surgery: a pragmatic approach to interpret equivocal evidence

BACKGROUND

Postoperative pulmonary complications remain the most significant cause of morbidity following open upper abdominal surgery despite advances in perioperative care. However, due to the poor quality primary research uncertainty surrounding the value of prophylactic physiotherapy intervention in the management of patients following abdominal surgery persists. The Delphi process has been proposed as a pragmatic methodology to guide clinical practice when evidence is equivocal.

METHODS

The objective was to develop a clinical management algorithm for the post operative management of abdominal surgery patients. Eleven draft algorithm statements extracted from the extant literature by the primary research team were verified and rated by scientist clinicians (n=5) in an electronic three round Delphi process. Algorithm statements which reached a priori defined consensus-semi-interquartile range (SIQR)<0.5-were collated into the algorithm.

RESULTS

The five panelists allocated to the abdominal surgery Delphi panel were from Australia, Canada, Sweden, and South Africa. The 11 draft algorithm statements were edited and 5 additional statements were formulated. The panel reached consensus on the rating of all statements. Four statements were rated essential.

CONCLUSION

An expert Delphi panel interpreted the equivocal evidence for the physiotherapeutic management of patients following upper abdominal surgery. Through a process of consensus a clinical management algorithm was formulated. This algorithm can now be used by clinicians to guide clinical practice in this population.

The influence of arm and shoulder position on the bear-hug, belly-press, and lift-off tests: an electromyographic study

BACKGROUND

Clinical testing for the integrity of the subscapularis muscle includes the belly-press, lift-off, and bear-hug examinations. While these tests have been widely applied in clinical practice, there is considerable variation in arm positioning within each clinical examination.

HYPOTHESIS

To determine the ideal arm and shoulder positions for isolating the subscapularis muscle while performing the bear-hug, belly-press, and lift-off tests.

STUDY DESIGN

Controlled laboratory study.

METHODS

The activity of 7 muscles was monitored in 20 healthy participants: upper and lower divisions of the subscapularis, supraspinatus, infraspinatus, latissimus dorsi, teres major, triceps, pectoralis major. Electromyogram data were collected and compared across each clinical test at varying arm positions: bear-hug (ideal position, 10° superior, 10° inferior to the shoulder line), belly-press (ideal position, maximum shoulder external rotation, and maximal shoulder internal rotation), and lift-off (ideal position, hand position 5 in. [12.7 cm] superior and 5 in. [12.7 cm] inferior to the midlumbar spine).

RESULTS

Regardless of arm and shoulder position, the upper and lower subscapularis muscle activities were significantly greater than all other muscles while performing each test. No significant differences were observed between the upper and lower subscapularis divisions at any position within and across the 3 tests. There were no significant differences in subscapularis electromyogram activities across the 3 tests.

CONCLUSION

The level of subscapularis muscle activation was similar among the bear-hug, belly-press, and lift-off tests. The 3 tests activated the subscapularis significantly more than all other muscles tested but were not different from one another when compared across tests and positions. Although the bear-hug and lift-off tests have been described to activate differential portions of the subscapularis, the findings of this study do not support the preferential testing of a specific subscapular division across the 3 tests. As such, all 3 tests are effective in testing the integrity of the entire subscapularis muscle, although there does not appear to be an ideal position for selectively testing its divisions.

CLINICAL RELEVANCE

Clinicians may feel comfortable in using any of the 3 tests, depending on the patient, to isolate the function of the subscapularis as a single muscle. Furthermore, clinicians should not solely focus on a patient's arm position when administering an examination but also compare the affected arm to the contralateral shoulder when appropriate.

The effect of platelet concentrates on graft maturation and graft-bone interface healing in anterior cruciate ligament reconstruction in human patients: a systematic review of controlled trials

PURPOSE

To systematically review the current evidence for the effects of platelet concentrates on (1) graft maturation and (2) graft-bone interface healing in anterior cruciate ligament (ACL) reconstruction in human, controlled trials and for ensuing differences in clinical outcomes.

METHODS

A systematic search of PubMed, CINAHL (Cumulative Index to Nursing and Allied Health Literature), Embase, Cochrane Central Register of Controlled Trials, and Cochrane Database of Systematic Reviews was performed for controlled trials of human ACL reconstruction with and without platelet concentrates. Data validity was assessed, and data were collected on graft maturation, graft-bone interface healing, and clinical outcome.

RESULTS

Eight studies met the inclusion criteria. Seven studies reported on graft maturation with significantly better outcomes in the platelet groups in 4, and there were large differences in means in an additional 2 studies. Five studies reported on tunnel healing, and 4 found no difference between groups. Three studies assessed clinical outcome but found no differences, regardless of whether they had shown a beneficial effect (1 of 3) or no effect (2 of 3) of platelets on graft and tunnel healing.

CONCLUSIONS

The current best evidence suggests that the addition of platelet concentrates to ACL reconstruction may have a beneficial effect on graft maturation and could improve it by 20% to 30% on average, but with substantial variability. The most likely mode of action is that treatment with platelets accelerates graft repopulation and remodeling, and this interpretation is supported by the existing data and is biologically plausible. However, the current evidence also shows only a very limited influence of platelet concentrates on graft-bone interface healing and no significant difference in clinical outcomes.

LEVEL OF EVIDENCE

Level III, systematic review of Level I, II, and III studies.

Rationale for and methods of superiority, noninferiority, or equivalence designs in orthopaedic, controlled trials

BACKGROUND

To provide value-based healthcare in orthopaedics, controlled trials are needed to assess the comparative effectiveness of treatments. Typically comparative trials are based on superiority testing using statistical tests that produce a p value. However, as orthopaedic treatments continue to improve, superiority becomes more difficult to show and, perhaps, less important as margins of improvement shrink to clinically irrelevant levels. Alternative methods to compare groups in controlled trials are noninferiority and equivalence. It is important to equip the reader of the orthopaedic literature with the knowledge to understand and critically evaluate the methods and findings of trials attempting to establish superiority, noninferiority, and equivalence.

QUESTIONS/PURPOSES

I will discuss supplemental and alternative methods to superiority for assessment of the outcome of controlled trials in the context of diminishing returns on new therapies over old ones.

METHODS

The three methods-superiority, noninferiority, and equivalence-are presented and compared, with a discussion of implied pitfalls and problems.

RESULTS

Noninferiority and equivalence offer alternatives to superiority testing and allow one to judge whether a new treatment is no worse (within a margin) or substantively the same as an active control. Noninferiority testing also allows for inclusion of superiority testing in the same study without the need for adjustment of the statistical methods.

CONCLUSIONS

Noninferiority and equivalence testing might prove most valuable in orthopaedic, controlled trials as they allow for comparative assessment of treatments with similar primary end points but potentially important differences in secondary outcomes, safety profiles, and cost-effectiveness.

Clinical trial design in non-invasive brain stimulation psychiatric research

Major depressive disorder (MDD) trials - investigating either non-pharmacological or pharmacological interventions - have shown mixed results. Many reasons explain this heterogeneity, but one that stands out is the trial design due to specific challenges in the field. We aimed therefore to review the methodology of non-invasive brain stimulation (NIBS) trials and provide a framework to improve clinical trial design. We performed a systematic review for randomized, controlled MDD trials whose intervention was transcranial magnetic stimulation (rTMS) or transcranial direct current stimulation (tDCS) in MEDLINE and other databases from April 2002 to April 2008. We created an unstructured checklist based on CONSORT guidelines to extract items such as power analysis, sham method, blinding assessment, allocation concealment, operational criteria used for MDD, definition of refractory depression and primary study hypotheses. Thirty-one studies were included. We found that the main methodological issues can be divided in to three groups: (1) issues related to phase II/small trials, (2) issues related to MDD trials and, (3) specific issues of NIBS studies. Taken together, they can threaten study validity and lead to inconclusive results. Feasible solutions include: estimating the sample size a priori; measuring the degree of refractoriness of the subjects; specifying the primary hypothesis and statistical tests; controlling predictor variables through stratification randomization methods or using strict eligibility criteria; adjusting the study design to the target population; using adaptive designs and exploring NIBS efficacy employing biological markers. In conclusion, our study summarizes the main methodological issues of NIBS trials and proposes a number of alternatives to manage them.

The prevalence and effect of publication bias in orthopaedic meta-analyses

BACKGROUND

Meta-analyses of randomized, controlled trials are considered the highest level-of-evidence, thus strongest source of information. However, questions concerning the validity of meta-analyses in orthopaedic surgery emerged recently. Among the most common sources for errors is publication bias. This describes the fact that studies with small or non-significant outcomes are less likely to be published, thus less likely to be identified and included in systematic reviews and meta-analyses. In this study we asked three questions: (1) Whether publication bias is assessed in orthopaedic meta-analyses, (2) What the actual prevalence of publication bias is, and (3) what effect publication bias has on the outcomes of orthopaedic meta-analyses.

METHODS

Using the estimate of 35 ± 20% for the prevalence of publication bias in meta-analyses obtained from earlier research we calculated a required samples size of 22 (plus 20% to account for attrition) and randomly selected 26 orthopaedic meta-analyses. To answer our first question we calculated the percentage of papers that report on formal assessment of publication bias. For our second question we obtained all primary studies (n = 321) from the included meta-analyses and used Egger's regression to search for evidence for publication bias. Third, we used the trim-and-fill method to assess the impact of publication bias, if present. This method estimates publication bias in a meta-analysis and adds hypothetical studies to reduce this bias; it thus produces an estimate of adjusted, unbiased outcomes that can be compared with the unadjusted, publication-biased outcomes to assess the effect of publication bias.

RESULTS

We found that only 35% (95% CI 20-57) of all orthopaedic meta-analyses published between 1992 and 2008 in English and German assessed publication bias. Most studies used funnel plots, which are rather insensitive. The prevalence of publication bias, based on a sensitivity analysis, ranged between 12 and 19%. Adjustment for publication bias did not produce significantly different results, but the magnitude of the pooled estimates in the affected meta-analyses changed by 29% (95% CI 0-63) on average.

CONCLUSION

We found a rather low prevalence of publication bias in orthopaedic meta-analyses, but recommend assessing for it and its effects, which might be substantial.

Comparison of different outcome instruments following foot and ankle trauma

BACKGROUND

Identifying optimal treatment strategies in patients with traumatic foot and ankle injuries has been hampered by the use of multiple available outcome measures with unproven reliability and validity. This prospective observational study aimed to measure the correlation between six functional outcome measures in patients with traumatic foot and ankle injuries.

MATERIALS AND METHODS

Patients 18 years of age or older with a traumatic foot or ankle injury completed the Short Form-12 (SF-12), Short Musculoskeletal Functional Assessment (SMFA), Foot Function Index (FFI), Foot and Ankle Ability Measure (FAAM), American Academy of Orthopedic Surgeons (AAOS), Foot and Ankle Questionnaire and American Orthopedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scale at a single followup visit. Raw scores for each of the outcome measures were calculated. Fifty-two patients were enrolled in our study. Pearson correlation coefficients provided measures of correlation.

RESULTS

Moderate to strong correlations were found for most pairwise comparisons of raw scores and functional categorical rankings (ρ=|0.5243 to 0.92|, p < 0.002). The strongest correlations were found between the SMFA, FFI, FAAM and AAOS Foot and Ankle Questionnaire.

CONCLUSION

High correlations between scores on six commonly used functional outcome instruments suggest it is likely unnecessary to use more than one instrument when examining functional outcome in patients with traumatic foot and ankle injuries. However, inconsistencies between measures in the same patient population suggest a need for further validation and scrutiny.

Second-generation highly cross-linked X3™ polyethylene wear: a preliminary radiostereometric analysis study

BACKGROUND

First-generation highly cross-linked polyethylene liners have reduced the incidence of wear particle-induced osteolysis. However, failed acetabular liners have shown evidence of surface cracking, mechanical failure, and oxidative damage. This has led to the development of second-generation highly cross-linked polyethylene, which has improved wear and mechanical properties and resistance to oxidation in vitro. Owing to its recent introduction, there are no publications describing its clinical performance.

QUESTIONS/PURPOSES

We assessed early clinical wear of a second-generation highly cross-linked polyethylene liner and compared its clinical performance with the published results of hip simulator tests and with first-generation highly cross-linked polyethylene annealed liners.

PATIENTS AND METHODS

Twenty-one patients were enrolled in a prospective cohort study. Clinical outcome and femoral head penetration were measured for 19 patients at 6 months and 1 and 2 years postoperatively.

RESULTS

The median proximal head penetration was 0.009 mm and 0.024 mm at 1 and 2 years, respectively. The median two-dimensional (2-D) head penetration was 0.083 mm and 0.060 mm at 1 and 2 years, respectively. The median proximal wear rate between 1 and 2 years was 0.015 mm/year.

CONCLUSIONS

The wear rate calculated was similar to the in vitro wear rate reported for this material; however, it was less than the detection threshold for this technique. Although longer followup is required for wear to reach a clinically quantifiable level, this low level of wear is encouraging for the future clinical performance of this material.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

The use of confidence intervals in reporting orthopaedic research findings

Conflict between clinical importance and statistical significance is an important problem in medical research. Although clinical importance is best described by asking for the effect size or how much, statistical significance can only suggest whether there is any difference. One way to combine statistical significance and effect sizes is to report confidence intervals. We therefore assessed the reporting of confidence intervals in the orthopaedic literature and factors influencing this frequency. In parallel, we tested the predictive value of statistical significance for effect size. In a random sample of predetermined size, we found one in five orthopaedic articles reported confidence intervals. Participation of an individual trained in research methods increased the odds of doing so fivefold. The use of confidence intervals was independent of impact factor, year of publication, and significance of outcomes. The probability of statistically significant results to predict at least a 10% between-group difference was only 69% (95% confidence interval, 55%-83%), suggesting that a high proportion of statistically significant results do not reflect large treatment effects. Confidence intervals could help avoid such erroneous interpretation by showing the effect size explicitly.

The quantitative analysis of back muscle degeneration after posterior lumbar fusion: comparison of minimally invasive and conventional open surgery

STUDY DESIGN

Prospective controlled study.

PURPOSE

The results of conventional open surgery was compared with those from minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) for lumbar fusion to determine which approach resulted in less postoperative paraspinal muscle degeneration.

OVERVIEW OF LITERATURE

MI TLIF is new surgical technique that appears to minimize iatrogenic injury. However, there aren't any reports yet that have quantitatively analyzed and proved whether there's difference in back muscle injury and degeneration between the minimally invasive surgery and conventional open surgery in more than 1 year follow-up after surgery.

METHODS

This study examined a consecutive series of 48 patients who underwent lumbar fusion in our hospital during the period, March 2006 to March 2008, with a 1-year follow-up evaluation using MRI. There were 17 cases of conventional open surgery and 31 cases of MI-TLIF (31 cases of single segment fusion and 17 cases of multi-segment fusion). The digital images of the paravertebral back muscles were analyzed and compared using the T2-weighted axial images. The point of interest was the paraspinal muscle of the intervertebral disc level from L1 to L5. Picture archiving and communication system viewing software was used for quantitative analysis of the change in fat infiltration percentage and the change in cross-sectional area of the paraspinal muscle, before and after surgery.

RESULTS

A comparison of the traditional posterior fusion method with MI-TLIF revealed single segment fusion to result in an average increase in fat infiltration in the paraspinal muscle of 4.30% and 1.37% and a decrease in cross-sectional area of 0.10 and 0.07 before and after surgery, respectively. Multi-segment fusion showed an average 7.90% and 2.79% increase in fat infiltration and a 0.16 and 0.10 decrease in cross-sectional area, respectively. Both single and multi segment fusion showed less change in the fat infiltration percentage and cross-sectional area, particularly in multi segment fusion. There was no significant difference between the two groups in terms of the radiologic results.

CONCLUSIONS

A comparison of conventional open surgery with MI-TLIF upon degeneration of the paraspinal muscle with a 1 year follow-up evaluation revealed that both single and multi segment fusion showed less change in fat infiltration percentage and cross-sectional area in the MI-TLIF but there was no significant difference between the two groups. This suggests that as time passes after surgery, there is no significant difference in the level of degeneration of the paraspinal muscle between surgical techniques.

Learning from past mistakes: assessing trial quality, power and eligibility in non-renal systemic lupus erythematosus randomized controlled trials

OBJECTIVES

To evaluate the post hoc study power of randomized controlled trials (RCTs) in the treatment of non-renal SLE and to determine the generalizability of these RCTs using an SLE database.

METHODS

RCTs in non-renal SLE were identified using PubMed (1975-2007). Inclusion/exclusion criteria, trial quality (5-point scale) and results of each study were recorded. The inclusion/exclusion criteria were compared with an SLE database to determine the proportion of patients from the database who would theoretically be eligible for these trials. For each negative study, we calculated the post hoc study power. We also looked for temporal improvements of trials in the literature and examined if pharmaceutical involvement influenced trial quality.

RESULTS

Sixty-four articles were included; the mean power of 30 negative studies was 24.6 +/- s.e.m. 3.9% (range 2.5-81.1%). Only one study had a power > 80%. Overall, potential eligibility of SLE patients in the database was 45.1 +/- s.e.m. 3.6%. Only 14 studies (21.9%) were of good quality. Fortunately, RCT quality is improving over time (trials <1995, compared with 1996-2002 and >2003; P < 0.001). Trials with pharmaceutical involvement had a significantly higher number of enrollees and better study quality.

CONCLUSIONS

Negative RCTs in SLE were mostly underpowered but the generalizability of these trials was high. Determination of study power and the impact of eligibility criteria on generalizability of study results are crucial in the design of clinical trials to ensure applicability to clinical practice.

Randomised controlled trials in orthopaedic surgery and traumatology: overview of parameters and pitfalls

There is a growing consensus that randomised controlled clinical trial (RCT) provide a secure basis for determining treatment effects. Prospective randomised clinical trials can be a powerful tool in medical science and evidence-based medicine. A well-defined study hypothesis, with a prospectively applied study design, blinded and randomised treatment allocation and assessment, with appropriate control groups can provide strong evidence in support of treatment decisions. However, the recent reviews of the medical literature indicate that the study design itself does not ensure the quality of science or useful and valid scientific data. Thus, regardless of the study design or level of evidence, it remains imperative for the physician and surgeon to critically evaluate a scientific report. Moreover, as randomisation, concealment of treatment allocation and blinding are difficult issues to resolve in orthopaedic surgery, future trials should focus on detailed and correct reporting of outcome measures.

Design considerations for randomised trials in orthopaedic fracture surgery

In the hierarchy of research designs, the results of randomised controlled trials are considered the highest level of evidence. Randomisation is the only method for controlling for both known and unknown prognostic factors between comparison groups. However, there are a number of challenges to conducting trials to evaluate surgical interventions. These include patient and surgeon preferences, inability to blind surgeons and difficulties blinding patients, difficulties in obtaining adequate sample sizes, and a lack of standardisation of surgical procedures. In this paper we address these issues and offer potential solutions within the context of conducting fracture trials in orthopaedics. Careful planning can help identify methodological issues, promote adaptive study designs, and lower the risk of bias to objectively assess new or existing surgical therapies.

Platelet gel supplementation in long bone nonunions treated by external fixation

OBJECTIVE

The aim of the present study was to evaluate the use of previously frozen, thawed platelet gel supplementation to accelerate the healing of long bone nonunions treated by external fixation.

DESIGN

Prospective case series with historical controls.

SETTING

University Hospital.

PATIENTS

Twenty patients affected by tibial, humeral, or forearm atrophic nonunions were treated by percutaneous stabilization with unilateral external fixators and injection of autologous platelet gel. The healing time was compared to the result obtained in a historical control group treated without platelet gel supplementation.

MAIN OUTCOME MEASUREMENTS

Consolidation rate and radiographic healing time of nonunions in the 2 groups were assessed by independent blinded observers. The nonunion was judged to be healed when bridging callus formation on both radiographic views was observed on at least 3 of 4 cortices.

RESULTS

The healing rate of nonunion was 90% (18/20) in platelet gel cases and 85% (17/20) in controls, respectively (P = 0.633). The mean time until radiographic consolidation in nonunions supplemented with platelet gel (147 +/- 63 days) was not different to the result in the control group (153 +/- 61 days; P = 0.784). Analyzing the mean healing time for separate segments, no differences were noted between study and control group-that is, tibia: 112 +/- 43 and 130 +/- 5 days, respectively (P = 0.382); humerus, 225 +/- 36 and 202 +/- 70 days, respectively (P = 0.530).

CONCLUSION

The present study failed to show the clinical usefulness of isolated percutaneous platelet gel supplementation in long bone nonunions treated by external fixation; however, caution should be exercised in interpreting this result because the actual numbers are small and the statistical power is limited.

Management of confounding in controlled orthopaedic trials: a cross-sectional study

Confounding occurs when the effect of an exposure on an outcome is distorted by a confounding factor and will lead to spurious effect estimates in clinical studies. Although confounding can be minimized at the design stage, residual confounding may remain. An argument therefore can be made for controlling for confounding during data analysis in all studies. We asked whether confounding is considered in controlled trials in orthopaedic research and hypothesized the likelihood of doing so is affected by participation of a scientifically trained individual and associated with the magnitude of the impact factor. We performed a cross-sectional study of all controlled trials published in 2006 in eight orthopaedic journals with a high impact factor. In 126 controlled studies, 20 (15.9%; 95% confidence interval, 9.5%-22.3%) studies discussed confounding without adjusting in the analysis. Thirty-eight (30.2%; 95% confidence interval, 22.2%-38.2%) controlled for confounding, although we suspect the true proportion might be somewhat higher. Participation of a methodologically trained researcher was associated with (odds ratio, 3.85) controlling for confounding, although there was no association between impact factor and controlling for confounding. The question remains to what extent the validity of published findings is affected by failure to control for confounding.