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Research Design

Principles of orthopaedic research design, focusing on evidence levels, the Fragility Index in RCTs, and reporting standards for biologic therapies.

Overview

Clinical research in orthopaedics faces significant methodological challenges that compromise the validity of findings. Simulations indicate that for most study designs and settings, a research claim is more likely to be false than true [4]. Bias introduces systematic error that distorts study results, requiring critical readers to rigorously review study design, conduct, and analysis to identify potential sources of bias [9]. Furthermore, readers must verify consistency with other studies before accepting observations as truth [9].

The quality of randomized controlled trials (RCTs) is frequently undermined by poor design choices. Key areas for improvement include avoiding unclear hypotheses, poor selection of endpoints, inappropriate subject selection criteria, inadequate randomisation, and insufficient blinding [3]. In upper-extremity trials specifically, there is a pressing need to improve reporting quality and increase the use of outcome measures covering various aspects of disability [5]. Additionally, authors, reviewers, and editors must avoid the Table I fallacy by ceasing to report p-values in baseline tables and heeding CONSORT advice against statistical testing of baseline characteristics [30].

Pilot studies often fail to translate into definitive trials, primarily due to poor feasibility such as recruitment issues and lack of funding [6]. Consequently, the majority of published pilot RCTs do not lead to definitive trials [6]. To address these limitations, the expertise-based randomized trial design offers substantial promise for enhancing feasibility and providing less biased results than conventional designs, though it is not a panacea [17]. Outcome estimation should therefore aim to identify clinically important differences, present effect measures with confidence intervals, and take necessary steps to minimize bias [8].

Despite the desirability of prospective public registration and timely publication of clinical trial results, substantial reluctance persists among researchers and editors regarding registration and result posting [29]. Existing legislation remains incompletely enforced, although editorial boards of the American Journal of Sports Medicine and Orthopaedic Journal of Sports Medicine have taken steps to require registration and accept trial design articles to accelerate progress [29].

Anatomy & Pathophysiology

General Principles and Assessment

Orthopaedic basic science encompasses biomechanics, molecular biology, and clinical management principles [2]. Fundamental principles of computer-assisted orthopaedic surgery (CAOS) involve correlating radiographic and anatomical data, a process increasingly important in joint arthroplasty, deformity correction, and spinal and trauma surgery [24].

Physical examination of the spine includes inspection, palpation, range of motion testing, and neurologic evaluation [48]. This examination aims to identify spinal pathology, nonspinal conditions, and signs of symptom magnification [48]. For ankle ligament injuries, accurate diagnosis requires an understanding of functional anatomy and biomechanics [68]. This diagnostic process necessitates a thorough history, physical examination, and appropriate radiographic studies, including stress radiographs [68]. Diagnosis must also include evaluation for concomitant injuries such as peroneal tendon subluxation or osteochondral lesions [68].

Spinal Anatomy and Biomechanics

Measurement of thoracic kyphosis (TK) with T2 on standing whole spinal radiographs resulted in a greater measurement error of up to 6.6° [60]. Preoperative planning for pedicle screw insertion in adolescent idiopathic scoliosis should be based on anatomical limitations in the apical vertebra region, apical vertebra level, and apical vertebral rotation degree [61]. Overall bone metabolism of the operated intervertebral disc space at six weeks had the highest diagnostic accuracy for predicting fusion status at one year after posterior lumbar interbody fusion [62].

Patients with idiopathic scoliosis employ two distinct strategies for head posture control: exaggerated swaying during static balance and restricted movement during dynamic activities [64]. These head posture control strategies may reflect compensatory mechanisms for sensorimotor deficits [64]. There is no need for additional training to improve postural control in adolescents with idiopathic scoliosis compared to their healthy peers [66].

Kinematics and Postural Control

A 3D protocol is technically feasible for analyzing postural balance in a freestanding posture [41]. A method to determine bilateral quarter para-sagittal planes in a 3D cervical vertebral body model is reproducible with high intra- and interobserver agreement [54]. The swimming test may represent a method of detecting true supraspinally controlled locomotion [56].

Shoulder Kinematics

Posterior and posterior superior labral (PPS) injuries produce alterations in glenohumeral (GH) kinematics [53]. PPS injuries have implications for GH joint instability, increased GH joint loading, and potential joint damage [53].

Classification

Study Design Quality: The quality of many randomized controlled trials (RCTs) could be improved by avoiding unclear hypotheses [3], poor selection of endpoints [3], inappropriate subject selection criteria [3], and inadequate randomisation or blinding [3]. A study's conclusions are only as strong as its methods [11]. Orthopaedic literature quality could improve if authors consider general study quality scoring systems, such as the Modified Coleman Methodology Score, when designing investigations [32], or condition-specific systems like the Newcastle-Ottawa Scale [32].

Diagnostic and Registry Standards: Further research is required to establish consistency in international diagnostic standards for microRNAs in osteoarthritis diagnosis [12]. The classification, measurement, and improvement of data quality in trauma registries is inconsistent [31]. Revised diagnostic criteria for rheumatoid arthritis were hoped to aid in obtaining more uniformity in patient classification [35]. Epidemiology and non-epidemiology-trained reviewers can apply levels-of-evidence guides to published studies with acceptable interobserver agreement [14], though the validity of the levels-of-evidence system remains a question for future research [14].

Other Considerations: For most study designs and settings, it is more likely for a research claim to be false than true [4]. The majority of published pilot RCTs did not lead to definitive trials [6], primarily due to poor feasibility, such as poor recruitment [6], and lack of funding [6]. Observed differences in knee scores between unmatched study groups are at least as likely to represent differences in patient populations as they are to represent differences in operative technique or implant design [36].

Clinical Presentation

History and Diagnostic Context: A detailed medical history is crucial for establishing a basic diagnosis, such as in overactive bladder where urodynamic evaluation may be necessary [28]. In thoracic outlet syndrome, diagnosis is often confounded by patients’ internet research and emotional problems resulting from symptoms and lack of appropriate treatment [19].

Physical Examination and Imaging: Knowledge of characteristic clinical presentations and physical examination findings for neurologic, musculoskeletal, vascular, and other etiologies helps distinguish the source of upper extremity pain quickly to facilitate appropriate diagnostic measures and treatment [27]. Muscle imaging can assist in recognizing atypical clinical presentations [7].

Investigations

Plain radiography: Standing X-rays are utilized to stabilize the evolution of degenerative lesions following double semitendinosus anterior cruciate ligament reconstruction, which efficiently restores satisfactory stability for most patients [26]. Roentgenographic evidence serves as an adjunct to define the degree and extent of involvement in osseous coccidioidomycosis [34]. Fundamental principles of correlating radiographic and anatomical data will become increasingly important in joint arthroplasty, deformity correction, and spinal and trauma surgery [24].

MRI: Magnetic resonance imaging indicates that the donor site after autologous osteochondral mosaicplasty for cartilaginous lesions of the elbow joint is resurfaced with fibrous tissue [50]. Muscle imaging aids in recognizing atypical clinical presentations, understanding the natural history of Pompe disease, and determining patients suited for treatment [7].

CT: A study on CT-based 3D preoperative planning for total knee arthroplasty focused on precision (reliability) rather than accuracy [46]. Intra-operative fluoroscopic 3D-imaging in calcaneal fracture surgery did not substantiate cost reduction through reduced peri-operative imaging or improved patient-relevant outcomes [49].

Other Considerations: The new European Bone and Joint Infection Society definition for prosthetic joint infection identifies more clinically important infections, accurately defines those with the highest risk of treatment failure, and reduces the number of patients with uncertain diagnoses [43]. Three-dimensional corrective exercise therapy for idiopathic scoliosis is being evaluated in a prospective non-randomized trial protocol [1]. Technologic advances in implant materials, design, amputee care, and imaging continue to drive improvements in patient care and outcomes in orthopaedic trauma [21]. Further research is required to establish consistency in international diagnostic standards for microRNAs in osteoarthritis and to address the limitations of traditional diagnostic methods [12].

The quality of many randomized controlled trials (RCT) can be improved by avoiding unclear hypotheses, poor selection of endpoints, inappropriate subject selection criteria, and inadequate randomisation or blinding [3]. The quality of reporting in upper-extremity randomized clinical trials needs improvement, and there is a need to increase the use of outcome measures covering different aspects of disability [5]. Bias leads to systematic error that distorts study findings, requiring critical readers to review study design, conduct, and analysis to propose potential sources of bias and check consistency with other studies [9]. A study's conclusions are only as strong as its methods [11]. Statistical significance is not the same as clinical significance, and readers must consider bias, confounding, sample size, and the role of chance when interpreting study findings [18]. Simulations indicate that for most study designs and settings, it is more likely for a research claim to be false than true [4]. Basic science topics in orthopaedics, including biomechanics, molecular biology, and clinical management principles, are covered in review questions and answers [2]. Bibliometric analysis of classic orthopedic publications serves as a guide for investigators in future research [10].

Treatment

Non-Operative

Conservative management is appropriate for most cases of snapping hip (coxa saltans), as the majority of presentations are asymptomatic [58]. For hallux rigidus and osteoarthrosis of the first metatarsophalangeal joint, non-operative measures constitute the initial tier of treatment options, with selection among these and surgical procedures dependent on disease stage and patient factors [44]. In the context of chronic, nonradicular, discogenic low back pain, treatment remains controversial; while intradiskal electrothermal therapy reports therapeutic success rates of 60% to 80%, precise quantification of clinical benefits requires proof in randomized prospective trials [55].

Operative

Indications: Surgical management is indicated for progressive, painful, unilateral coxa vara deformity or leg-length discrepancy in childhood, whereas moderate nonprogressive deformity often does not require surgery [45]. For idiopathic scoliosis, three-dimensional corrective exercise therapy is currently being evaluated in a prospective non-randomized trial protocol [1].

Surgical Approach / Technique: Double semitendinosus anterior cruciate ligament reconstruction is efficient in restoring satisfactory stability for most patients and stabilizes the evolution of degenerative lesions, as demonstrated by standing X-ray [26]. Routine application of the pectoralis major index technique may improve the accurate identification of structurally significant rupture and expedite referral to a surgical specialist for optimal treatment and outcome [52].

Implant Selection: Technologic advances in implant materials and design continue to drive improvements in patient care and outcomes [21]. For hallux rigidus and osteoarthrosis of the first metatarsophalangeal joint, surgical procedures include cheilectomy, arthroplasty, and arthrodesis [44].

Adjuncts: The quality of randomised controlled trials can be improved by avoiding unclear hypotheses, poor endpoint selection, inappropriate subject selection criteria, and inadequate randomisation or blinding [3]. Simulations indicate that for most study designs and settings, it is more likely for a research claim to be false than true [4]. Outcome estimation should aim to identify a clinically important difference, present measures of effects with confidence intervals, and take steps to minimize bias [8].

Other Considerations: Basic science topics in orthopaedics, including biomechanics and molecular biology, are covered in review texts [2]. Bibliometric analysis of classic orthopedic publications serves as a guide for future investigators [10]. Predictive biomarkers are needed to better assess clinical course and treatment efficacy to enable individualized therapy [13]. Epidemiology and non-epidemiology-trained reviewers can apply levels-of-evidence guides to published studies with acceptable interobserver agreement, though the validity of the system remains a question [14]. Pooling heterogeneous, low-evidence, high-bias data results in incorrect conclusions; systematic reviews should instead explore heterogeneity to identify strengths and deficiencies in current literature and guide future research [15]. Expertise-based randomized trials are viewed as an option that holds promise to provide less biased results than conventional designs and enhance feasibility of conducting randomized controlled trials in surgery, though they are not a panacea [17].

All existing clinical studies evaluating mesenchymal stem cells for orthopaedic or sports medicine applications are limited by inadequate reporting of preparation protocols and composition [51]. Most orthopaedic published investigations on platelet-rich plasma lack reporting of preparation methods or composition, making studies unreproducible and outcomes unverifiable [59]. The quality of reporting in upper-extremity randomized clinical trials needs improvement, including increased use of outcome measures covering different aspects of disability [5]. The majority of published pilot randomized controlled trials in orthopaedic surgery do not lead to definitive trials, primarily due to poor feasibility (e.g., poor recruitment) and lack of funding [6].

Complications

The validity of complication data is contingent upon rigorous study design, as conclusions are only as strong as their methods [11]. Common pitfalls in randomized controlled trials that can lead to erroneous conclusions include unclear hypotheses, poor selection of endpoints, inappropriate subject selection criteria, and inadequate randomisation or blinding [3]. Bias leads to systematic error that distorts study findings [9], and outcome estimation must take necessary steps to minimize bias [8]. It is more likely for a research claim to be false than true for most study designs and settings [4]. Pooling heterogeneous, low-evidence, high-bias data results in incorrect conclusions [15]; instead, systematic reviews should explore heterogeneity to identify strengths and deficiencies in current literature and guide future research rather than pooling such data [15].

Infection (PJI): Administrative databases are used for detecting rare complications [42]. Researchers must understand the limitations and methodological issues of administrative databases to avoid erroneous conclusions [42].

Nerve palsy: The minimum length of follow-up for nerve repairs is 12 months [16].

Stiffness / Arthrofibrosis: The minimum length of follow-up for general functional outcomes is no less than 6 months [16].

Joint function recovery: The minimum length of follow-up for joint function recovery is 2 years [16].

Other Considerations: Longitudinal studies require continued contact and evaluation of patients for many years after treatment administration [23]. Every reasonable effort should be made to obtain information on all patients in a study to ensure meaningful data [23]. Further studies with long-term follow-up are needed to determine whether grafted areas will maintain structural and functional integrity over time [20]. The timing of clinical events such as complications can be important in determining which event might be a precursor to a subsequent event [25]. Continuous outcomes are less fragile than dichotomous outcomes [33]. Negligible dichotomous outcomes are particularly more fragile [33]. Confounder selection should control for each covariate that is a cause of the exposure, or of the outcome, or of both [47]. Confounder selection should exclude any variable known to be an instrumental variable [47].

Recovery

Light activity (weeks): Evidence does not specify a week range for light activity or return to desk work in the provided data.

Full activity (months): Evidence does not specify a month range for full activity or sport return in the provided data.

Complete recovery / outcome plateau (months): The minimum length of follow-up for general functional outcomes in hand surgery reports is no less than 6 months [16]. The minimum length of follow-up for nerve repairs in hand surgery reports is 12 months [16]. The minimum length of follow-up for joint function recovery in hand surgery reports is 2 years [16]. Further studies with long-term follow-up are needed to determine whether the grafted area maintains structural and functional integrity over time after Autologous Matrix-Induced Chondrogenesis for focal cartilage defects in the knee [20].

Rehabilitation protocol: Evidence does not specify PT phasing, immobilisation duration, or weight-bearing progression in the provided data.

Functional milestones: The Musculoskeletal Function Assessment Questionnaire was more responsive than the SF-36 and more efficient in measuring changes in function between baseline and follow-up values [39]. Physical outcome measures such as range of motion and strength are not as reliable as patient-reported outcomes in orthopaedic research [38].

Other Considerations: Preoperative symptom duration of two years or greater does not result in inferior patient-reported outcomes or clinical outcomes compared to symptom duration of less than 2 years at mid-term follow-up after high tibial osteotomy [65]. Early reimplantation in abbreviated two-stage exchange provides similar outcomes to traditional two-stage exchange, though optimal timing and selection criteria remain undefined [63]. The two designs of mobile and fixed-bearing all-polyethylene tibial components functioned equivalently at the time of early follow-up in low-to-moderate-demand patient groups [40].

Key Evidence

  • [L3] This document is a study protocol for a prospective non-randomized trial and does not report results or conclusions. (10.1186/s12891-022-05057-7)
  • [Paper] The quality of many RCTs could be improved by avoiding common pitfalls such as unclear hypotheses, poor selection of endpoints, inappropriate subject selection criteria, and inadequate randomisation or blinding. (10.1016/j.injury.2010.03.033)
  • [L5] Simulations show that for most study designs and settings, it is more likely for a research claim to be false than true. (10.1371/journal.pmed.0020124)
  • [L2] There is a need to improve the quality of reporting of upper-extremity randomized clinical trials and to increase the use of outcome measures covering different aspects of disability. (10.1016/j.jhsa.2004.04.003)
  • [L1] However, the majority of published pilot RCTs did not lead to definitive trials, a discrepancy mainly attributed to poor feasibility (e.g. poor recruitment) and lack of funding. (10.1186/s12891-018-2337-7)
  • [L5] Muscle imaging can help for recognition of atypical clinical presentations, for understanding the natural history of the disease, and for determining patients suited for treatment. (10.1186/1471-2474-14-s2-o2)
  • [L5] Outcome estimation should aim at identifying a clinically important difference, at presenting measures of effects with confidence intervals and at taking the necessary steps to minimize bias. (10.1302/2058-5241.3.170064)
  • [L5] Bias leads to systematic error that distorts study findings; the critical reader must review study design, conduct, and analysis to propose potential sources of bias and check consistency with other studies before accepting observations as truth. (10.1177/0363546520944881)
  • [L5] It serves as a guide for investigators in the future research. (10.1186/s13018-019-1247-1)
  • [L5] A study's conclusions are only as strong as its methods. (10.1016/j.arthro.2021.06.037)
  • [L1] To establish consistency in international diagnostic standards and address the limitations of traditional diagnostic methods, further research is required for validation. (10.1186/s13018-025-06059-6)
  • [Paper] Predictive biomarkers are needed to better assess clinical course and treatment efficacy to enable individualized therapy. (10.1007/s00120-008-1745-y)
  • [L4] Epidemiology and non-epidemiology-trained reviewers can apply the levels-of-evidence guide to published studies with acceptable interobserver agreement, though the validity of this system remains a question for future research. (10.2106/00004623-200408000-00016)
  • [L5] Pooling heterogeneous, low-evidence, high-bias data results in incorrect conclusions; instead, systematic reviews should explore heterogeneity to identify strengths and deficiencies in current literature and guide future research. (10.1016/j.arthro.2018.10.005)
  • [L5] The editors provide guidelines on required lengths of follow-up in clinical reports, suggesting no less than 6 months for general functional outcomes, 12 months for nerve repairs, and 2 years for joint function recovery, while noting that these are considerations rather than fixed academic rules. (10.1177/1753193418821101)
  • [Letter] The authors view the expertise-based design as an option that holds substantial promise to provide less biased results than the conventional design and to enhance feasibility of conducting randomized controlled trials in surgery, though they do not view it as a panacea. (10.1007/s11999-008-0576-x)
  • [L5] Statistical significance is not the same as clinical significance, and readers must consider bias, confounding, sample size, and the role of chance when interpreting study findings. (10.1177/036354659602400626)
  • [L5] This takes time and effort and is often confounded by the patient's research on the internet and emotional problems usually resulting from the symptoms and lack of appropriate treatment. (10.1016/s0749-0712(03)00080-5)
  • [L4] However, further studies with long-term follow-up are needed to determine whether the grafted area will maintain structural and functional integrity over time. (10.1007/s00167-010-1042-3)
  • [L5] Longitudinal studies require continued contact and evaluation of patients for many years after the administration of treatment, and every reasonable effort should be made to obtain information on all patients in a study to ensure meaningful data. (10.2106/00004623-199803000-00018)
  • [L5] It emphasizes that while individual systems will evolve, the fundamental principles of correlating radiographic and anatomical data will become increasingly important in joint arthroplasty, deformity correction, and spinal and trauma surgery. (10.1016/j.injury.2004.05.005)
  • [L5] Clinicians are well aware that treatment decisions evolve over time and that the timing of clinical events such as complications can be important in determining which event might be a precursor to a subsequent event. (10.1016/j.injury.2018.08.001)
  • [L4] The study shows that the procedure is efficient in restoring a satisfactory stability for most patients and stabilises the evolution of the degenerative lesions as shown by standing X-ray. (10.1007/s001670050076)
  • [L5] Knowledge of the characteristic clinical presentation and physical examination findings of neurologic, musculoskeletal, vascular, and other etiologies can help distinguish the source of upper extremity pain quickly to facilitate appropriate diagnostic measures and treatment. (10.5435/jaaos-d-11-00086)
  • [L5] A sufficient basic diagnosis including a detailed medical history and, if necessary, urodynamic evaluation is crucial. (10.1007/s00120-014-3718-7)
  • [L5] Prospective public registration of clinical trials and timely publication or posting of results are desirable goals, yet surveys show substantial reluctance among researchers and editors; existing legislation is incompletely enforced, though editorial boards of AJSM and OJSM have recently taken steps to require registration and accept trial design articles to accelerate progress. (10.1177/0363546515614340)
  • [L4] Authors, reviewers, and editors should be aware of the Table I fallacy, follow the CONSORT Statement which advises against statistical tests of baseline characteristics, and stop reporting p values in baseline tables of RCTs. (10.2106/jbjs.21.01166)
  • [L2] The classification, measurement and improvement of data quality in trauma registries is inconsistent. (10.1016/j.injury.2016.01.007)
  • [L5] The quality of orthopaedic literature could improve if authors consider general and condition-specific study quality scoring systems, such as the Modified Coleman Methodology Score and Newcastle-Ottawa Scale, when designing their investigations to ensure comprehensive data input and robust study design. (10.1016/j.arthro.2023.08.008)
  • [L1] Continuous outcomes are less fragile than dichotomous outcomes, with negligible dichotomous outcomes being particularly more fragile. (10.5435/jaaos-d-24-00691)
  • [L4] Roentgenographic evidence serves as an adjunct to define the degree and extent of involvement. (10.2106/00004623-197153060-00012)
  • [L5] The revised criteria are hoped to aid in obtaining more uniformity in the classification of patients with rheumatoid arthritis and should be reviewed in two or three years. (10.2106/00004623-195941040-00023)
  • [L4] Observed differences in knee scores between different study groups that have not been matched for various clinically relevant factors are at least as likely to represent differences in the patient populations as they are to represent differences in the operative technique or the design of the implant. (10.2106/00004623-199706000-00009)
  • [Paper] Physical outcome measures are being changed for the use of patient reported outcomes, and range of motion and strength are not as reliable measures as one would think. (10.1016/j.injury.2019.11.017)
  • [L3] It was more responsive than the SF-36 and more efficient in measuring changes in function between baseline and follow-up values. (10.2106/00004623-199709000-00006)
  • [L1] The two designs functioned equivalently at the time of early follow-up in this low-to-moderate-demand patient group. (10.2106/jbjs.j.00157)
  • [L5] The study demonstrates the technical feasibility of a 3D protocol to analyze postural balance in a freestanding posture. (10.1016/j.otsr.2011.12.001)
  • [L5] Administrative databases are gaining popularity for investigating clinical outcomes, monitoring practice trends, and detecting rare complications, but researchers must understand their limitations and methodological issues to avoid erroneous conclusions. (10.1016/j.csm.2018.03.002)
  • [L5] The new European Bone and Joint Infection Society definition offers advantages in clinical practice by identifying more clinically important infections, accurately defining those with the highest risk of treatment failure, and reducing the number of patients with uncertain diagnoses. (10.1530/eor-23-0044)
  • [L5] Treatment options range from non-operative measures to various surgical procedures including cheilectomy, arthroplasty, and arthrodesis, with selection depending on disease stage and patient factors. (10.2106/00004623-199806000-00015)
  • [L5] Surgical management is indicated for progressive, painful, unilateral deformity or leg-length discrepancy, while moderate nonprogressive deformity often does not require surgery. (10.5435/00124635-199803000-00003)
  • [L5] The authors responded to concerns regarding their study on CT-based 3D preoperative planning for total knee arthroplasty, clarifying that their investigation focused on precision (reliability) rather than accuracy, and addressed methodological questions about exclusion criteria, CT scan protocols, and component sizing criteria. (10.1016/j.arth.2018.01.049)
  • [Paper] The proposal recommends controlling for each covariate that is a cause of the exposure, or of the outcome, or of both, while excluding any variable known to be an instrumental variable. (10.1007/s10654-019-00494-6)
  • [Paper] No substantiation for cost reduction was found through reduction in peri-operative imaging or in terms of improved patient-relevant outcomes. (10.1007/s00402-017-2787-7)
  • [L4] However, magnetic resonance imaging indicates that the donor site is resurfaced with fibrous tissue. (10.1177/0363546507306465)
  • [L1] All existing clinical studies evaluating MSCs for orthopaedic or sports medicine applications are limited by inadequate reporting of both preparation protocols and composition. (10.1177/0363546518758667)
  • [L2] Routine application of the PMI technique by clinicians may improve accurate identification of structurally significant rupture and expedite referral to a surgical specialist for optimal treatment and outcome. (10.1177/2325967113516729)
  • [L5] The PPS injury produces alterations in GH kinematics with implications for GH joint instability, increased GH joint loading, and potential joint damage. (10.1016/j.jse.2024.12.023)
  • [L4] The study proposed an approach to determine bilateral quarter para-sagittal planes in a 3D cervical vertebral body model, demonstrating that the method is reproducible with high intra- and interobserver agreement. (10.1186/s13018-021-02648-3)
  • [L5] The treatment of chronic, nonradicular, discogenic low back pain remains controversial, and while intradiskal electrothermal therapy shows reported therapeutic success rates of 60% to 80%, a more precise quantification of clinical benefits remains to be proved in randomized prospective trials. (10.5435/00124635-200301000-00003)
  • [L5] The swimming test may represent a method of detecting true supraspinally controlled locomotion. (10.1016/j.injury.2009.01.038)
  • [L5] Most cases of snapping hip are asymptomatic and can be treated conservatively. (10.5435/00124635-199509000-00006)
  • [L5] Recent research shows that most orthopaedic published investigations on platelet-rich plasma lack reporting of preparation methods or PRP composition, making studies unreproducible and outcomes unverifiable. (10.1016/j.arthro.2024.04.026)
  • [L3] Measurement of TK with T2 on standing whole spinal radiographs resulted in a greater measurement error of up to 6.6°. (10.1186/s12891-021-04786-5)
  • [L4] Preoperative planning to accurately select and insert pedicle screws in adolescent idiopathic scoliosis should be based on anatomical limitations in the apical vertebra region, apical vertebra level, and apical vertebral rotation degree. (10.1186/s12891-022-05799-4)
  • [L2] Overall bone metabolism of the operated intervertebral disc space at six weeks had the highest diagnostic accuracy for predicting the fusion status at one year. (10.1186/s13018-025-05814-z)
  • [L1] Early reimplation (abbreviated two-stage) provides similar outcomes to traditional two-stage exchange, though optimal timing and selection criteria remain undefined. (10.1016/j.arth.2025.10.075)
  • [L3] Patients with idiopathic scoliosis employ two distinct strategies for head posture control: exaggerated swaying during static balance and restricted movement during dynamic activities, which may reflect compensatory mechanisms for sensorimotor deficits. (10.1186/s13018-025-06535-z)
  • [L4] Patients with a preoperative duration of symptomatic medial knee overload/arthritis of two years or greater do not experience inferior PRO or clinical outcomes than patients with a symptom duration of less than 2 years at mid-term follow-up. (10.1016/j.jisako.2022.03.003)
  • [L4] Therefore, there is no need for additional training to improve postural control in these adolescents with idiopathic scoliosis. (10.1186/s12891-024-08210-6)
  • [L5] An accurate diagnosis of ankle ligament injuries requires an understanding of functional anatomy and biomechanics, a thorough history, physical examination, and appropriate radiographic studies, including stress radiographs, while also evaluating for concomitant injuries such as peroneal tendon subluxation or osteochondral lesions. (10.2106/00004623-199407000-00022)

References

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[9] The Critical Reader—Bias. The American Journal of Sports Medicine. 2020. DOI: 10.1177/0363546520944881

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[11] Best Practice Guidelines for Propensity Score Methods in Medical Research: Consideration on Theory, Implementation, and Reporting. A Review. Arthroscopy. 2021. DOI: 10.1016/j.arthro.2021.06.037

[12] MicroRNAs in the diagnosis of osteoarthritis: a systematic review and meta-analysis of observational studies. Journal of Orthopaedic Surgery and Research. 2025. DOI: 10.1186/s13018-025-06059-6

[13] Molekularpathologische Bestimmung prädiktiver Biomarker. Der Urologe. 2008. DOI: 10.1007/s00120-008-1745-y

[14] Interobserver Agreement in the Application of Levels of Evidence to Scientific Papers in the American Volume of The Journal of Bone and Joint Surgery. The Journal of Bone and Joint Surgery-American Volume. 2004. DOI: 10.2106/00004623-200408000-00016

[15] Reviews Pooling Heterogeneous, Low‐Evidence, High‐Bias Data Result in Incorrect Conclusions: But Heterogeneity is an Opportunity to Explore. Arthroscopy. 2018. DOI: 10.1016/j.arthro.2018.10.005

[16] The minimum length of follow-up in hand surgery reports. Journal of Hand Surgery (European Volume). 2019. DOI: 10.1177/1753193418821101

[17] Reply to Letter to Editor: Orthopaedic Surgeons Prefer to Participate in Expertise-based Randomized Trials. Clinical Orthopaedics & Related Research. 2009. DOI: 10.1007/s11999-008-0576-x

[18] A Statistics Primer. The American Journal of Sports Medicine. 1996. DOI: 10.1177/036354659602400626

[19] Diagnosing thoracic outlet syndrome. Hand Clinics. 2004. DOI: 10.1016/s0749-0712(03)00080-5

[20] Mid‐term results of Autologous Matrix‐Induced Chondrogenesis for treatment of focal cartilage defects in the knee. Knee Surgery, Sports Traumatology, Arthroscopy. 2010. DOI: 10.1007/s00167-010-1042-3

[21] Chapter 3 Emerging Technologies in Orthopaedic Trauma. 2021.

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