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Evidence. Clarity. Practice.

© 2026 OrthoVellum. For educational purposes only.

Not medical advice. Verify clinically important information against current local guidance.

Landmark Trials in Orthopaedics

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Landmark Trials in Orthopaedics

Advanced orthopaedic guide to landmark trials across trauma, sports, arthroplasty, spine and paediatrics, including DRAFFT, PROFHER, FLOW, FAITH, HEALTH, FORCE, KANON, METEOR, FIDELITY, MOON, CRISTAL, EPCAT II and SPORT.

complete
Reviewed: 2026-06-03Maintained by OrthoVellum Medical Education Team

Editorially maintained by OrthoVellum Editorial Team

Clear references, transparent review, and correction process • Published by OrthoVellum Medical Education Team

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Educational disclosure

Educational content is reviewed for source visibility, editorial coherence, and correction readiness.

No individual clinician credential is claimed unless a named person is shown.

Verify before clinical use; this is not medical advice or a substitute for local guidance.

High Yield Overview

Landmark Orthopaedic Trials

Know the question | know the population | know the limit

PICOfirst step before using any trial
Primary outcomethe result the trial was powered to answer
Crossovercommon in surgical trials
Applicabilitydecides whether the result fits your patient

Landmark Trial Families

Trauma
PatternFracture fixation, open fracture care, hip fracture arthroplasty and paediatric fracture immobilisation.
TreatmentDRAFFT, PROFHER, FLOW, FAITH, HEALTH and FORCE.
Sports and knee
PatternACL strategy, meniscal surgery, degenerative tears and outcomes cohorts.
TreatmentKANON, METEOR, FIDELITY and MOON.
Arthroplasty
PatternThromboprophylaxis, registry-nested comparisons and peri-operative pathways.
TreatmentCRISTAL, EPCAT II and registry signals.
Spine
PatternSurgery versus non-operative care for common lumbar degenerative conditions.
TreatmentSPORT disc herniation, spinal stenosis and degenerative spondylolisthesis.

Critical Must-Knows

  • A landmark trial is not an automatic rule. It is a strong decision anchor only when the patient, intervention, comparator and outcome match the case.
  • Surgical trials often have crossover and incomplete blinding. Interpret intention-to-treat and as-treated results carefully.
  • The primary outcome matters. A trial powered for function may not answer rare complications, implant survival or subgroup effects.
  • Negative does not mean useless. Many trials show that routine surgery adds little for broad low-risk groups but may still help selected patients.
  • Trial literacy changes management discussions. It improves consent, shared decision-making and avoidance of low-value surgery.

Clinical Pearls

  • "
    Open every trial discussion with the PICO and the primary outcome.
  • "
    State what the trial changed and what it did not answer.
  • "
    Be careful applying pragmatic trial results to excluded high-risk subgroups.
  • "
    In fracture trials, distinguish radiographic success from patient-centred function and reoperation.
  • "
    In arthroplasty prophylaxis trials, separate symptomatic VTE, bleeding, mortality and protocol context.

Do not quote a trial without stating the patient group

“PROFHER showed no difference” or “DRAFFT changed distal radius fixation” is incomplete. A useful answer states the population, comparator, outcome and limitation. The wrong extrapolation is often more dangerous than not knowing the acronym.

Map of landmark orthopaedic trials by subspecialty
Landmark trials sit across trauma, sports/knee, arthroplasty and spine. The key is not the acronym; it is knowing which clinical decision each study helps answer.Credit: Original OrthoVellum illustration

How to Use a Trial

PICOQuestion
SAFEValidity
CASTClinical use
P
Patient
Age, injury, severity, setting and exclusions.
S
Selection
Who was included and excluded?
C
Context
Does the trial setting match yours?
I
Intervention
Operation, implant, pathway or medication.
A
Allocation
Was randomisation protected?
A
Absolute effect
What is the real size of benefit or harm?
C
Comparator
Non-operative care, another operation or placebo.
F
Follow-up
Was outcome capture complete?
S
Subgroups
Was this subgroup powered or exploratory?
O
Outcome
Function, reoperation, complications, mortality or cost.
E
Endpoint
Was the primary outcome clinically meaningful?
T
Tradeoff
What are the risks, costs and downstream procedures?

No PICO, no application.

A famous trial can still have limits.

Cast evidence onto the actual patient.

PICOQuestion
P
Patient
Age, injury, severity, setting and exclusions.
I
Intervention
Operation, implant, pathway or medication.
C
Comparator
Non-operative care, another operation or placebo.
O
Outcome
Function, reoperation, complications, mortality or cost.

No PICO, no application.

SAFEValidity
S
Selection
Who was included and excluded?
A
Allocation
Was randomisation protected?
F
Follow-up
Was outcome capture complete?
E
Endpoint
Was the primary outcome clinically meaningful?

A famous trial can still have limits.

CASTClinical use
C
Context
Does the trial setting match yours?
A
Absolute effect
What is the real size of benefit or harm?
S
Subgroups
Was this subgroup powered or exploratory?
T
Tradeoff
What are the risks, costs and downstream procedures?

Cast evidence onto the actual patient.

Overview

Landmark trials are studies that changed, challenged or clarified common orthopaedic decisions. They are most useful when they are remembered as clinical questions rather than as acronyms.

A good landmark-trial discussion should answer:

  • What patient population was studied?
  • What was the intervention and comparator?
  • What primary outcome was used?
  • What was the practice signal?
  • What are the limitations and excluded patients?
  • How should the result affect consent and management?

The complete one-sentence trial answer

“This trial asked whether intervention X compared with Y improved outcome Z in patient group P; the main signal was this, but I would not apply it automatically to these excluded or higher-risk patients.”

Concepts and Core Principles

Workflow from trial result to clinical decision
A landmark result should pass through PICO, validity, effect size, applicability and harm assessment before it changes a clinical decision.Credit: Original OrthoVellum illustration
CONSORT participant flow diagram for a two-group randomised trial
Participant flow matters because exclusions, allocation, crossover, follow-up loss and analysis sets can change how a landmark trial should be interpreted.Credit: Adapted from Hopewell et al., Trials, 2011, CC BY 2.0

What Makes a Trial Practice-Changing?

DomainQuestionWhy It Matters
Clinical relevanceDoes the trial answer a decision surgeons face often?Common decisions such as distal radius fixation or proximal humerus surgery affect many patients.
Internal validityWere randomisation, allocation, follow-up and outcome assessment credible?A flawed trial can mislead even if large.
Effect sizeIs the difference clinically meaningful, not just statistically significant?Small differences may not justify operative risk.
ApplicabilityDo the inclusion criteria match the patient in front of you?A trial may exclude severe displacement, open injury, frailty or revision cases.
Downstream consequencesDid the trial capture reoperation, complications, cost and later crossover?Orthopaedic decisions often have delayed consequences.

Classification of Landmark Trials

Trial Style

StyleStrengthLimitation
Explanatory trialTests whether an intervention can work under controlled conditions.May not represent everyday surgical practice.
Pragmatic trialTests whether a strategy works in real clinical settings.Treatment heterogeneity and crossover can dilute the result.

Result Framing

DesignQuestionTrap
SuperiorityIs one treatment better than another?A negative trial may be underpowered rather than proof of equality.
EquivalenceAre treatments clinically similar within a margin?The margin must be clinically acceptable.
Non-inferiorityIs the simpler or safer treatment not unacceptably worse?Protocol deviations and crossover can bias toward non-inferiority.

Evidence Type

TypeBest UseLimitation
Randomised trialTreatment comparison where randomisation is ethical and feasible.May be small, selected or affected by crossover.
Registry studyImplant survivorship, rare complications and real-world variation.Confounding and coding limitations.
Prospective cohortPrognosis, predictors and long-term outcomes.Causation is weaker without randomisation.

Trauma Trials

Trauma Trial Signals

TrialClinical QuestionPractice Signal
DRAFFTFor adult dorsally displaced distal radius fractures, how do K-wires and volar locking plates compare?Plate fixation was challenged as routine treatment for broad displaced distal radius fracture groups; cost, reoperation and patient selection matter.
DRAFFT 2After manipulation of dorsally displaced distal radius fractures, is K-wire fixation better than moulded cast?Moulded cast was a serious comparator after acceptable reduction; avoid automatic fixation when stability and patient factors permit casting.
PROFHERFor displaced proximal humerus fractures in adults, does surgery improve patient-reported outcomes over non-operative care?Routine surgery for many displaced proximal humerus fractures was strongly challenged; selected fracture patterns and younger/high-demand patients still need individual assessment.
FLOWIn open fractures, what irrigation pressure and solution should be used?Very high pressure lavage did not become the default; soap solution raised concern. Normal saline and sensible pressure remain common practice anchors.
FAITHFor femoral neck fracture fixation, do sliding hip screws and cancellous screws differ?Implant choice must be matched to fracture biology, displacement and patient factors; fixation failure remains central.
HEALTHFor displaced femoral neck fracture in independently ambulatory older adults, THA or hemiarthroplasty?THA gave modest functional advantages in selected patients but with tradeoffs including dislocation; selection is key.
FORCEFor paediatric distal radius torus fractures, bandage or rigid immobilisation?Simple bandage and discharge strategy is reasonable for uncomplicated torus fractures, reducing overtreatment.

Trauma trial limitation

Fracture trials usually answer a strategy question for a defined injury group. They do not remove the need to assess displacement, soft tissue, bone quality, open injury, neurovascular status, patient demand and ability to comply with follow-up.

Sports and Knee Trials

Sports and Knee Trial Signals

TrialClinical QuestionPractice Signal
KANONEarly ACL reconstruction versus structured rehabilitation with optional delayed reconstruction.Not every ACL rupture requires immediate reconstruction; instability episodes, goals, pivoting sport and meniscal risk guide individual decisions.
METEORArthroscopic partial meniscectomy versus physical therapy in meniscal tear with osteoarthritis.Physical therapy is a strong first-line option for many degenerative meniscal tears with OA; crossover matters.
FIDELITYArthroscopic partial meniscectomy versus sham surgery for degenerative meniscal tear.Routine arthroscopic partial meniscectomy for degenerative meniscal symptoms without clear mechanical indication was strongly challenged.
MOONProspective ACL cohort evidence on outcomes, graft choice and predictors.Useful for prognosis and counselling, but not a single randomised treatment rule.

Degenerative meniscus discussion

The central counselling point is not “arthroscopy never works.” It is that high-quality evidence has narrowed the indication: degenerative meniscal symptoms with osteoarthritis usually need education, rehabilitation and non-operative care before considering arthroscopy, unless there is a specific mechanical problem or atypical scenario.

Arthroplasty Trials

Arthroplasty Trial Signals

TrialClinical QuestionPractice Signal
CRISTALAspirin versus enoxaparin for symptomatic VTE prevention after hip or knee arthroplasty.Enoxaparin performed better for symptomatic VTE in the trial context; prophylaxis choice must account for local protocol, bleeding risk and patient risk.
EPCAT IIAfter initial rivaroxaban, can aspirin continue extended prophylaxis after hip or knee arthroplasty?Aspirin can be part of selected sequential prophylaxis pathways; do not confuse this with aspirin-only from day zero for all patients.
Registry signalsWhich implants, bearings or fixation strategies survive in real-world use?Registry findings are powerful for implant surveillance but remain observational and confounded.

Spine Trials

Spine Trial Signals

TrialClinical QuestionPractice Signal
SPORT disc herniationSurgery versus non-operative care for lumbar disc herniation.Surgery can provide faster symptom relief for selected patients; long-term interpretation is affected by crossover.
SPORT spinal stenosisDecompression strategy versus non-operative care for symptomatic lumbar stenosis.Supports benefit of surgery in selected symptomatic stenosis, but patient selection and expectations matter.
SPORT degenerative spondylolisthesisSurgery versus non-operative care for degenerative spondylolisthesis with stenosis.Supports surgery for selected symptomatic patients, but treatment choice depends on instability, deformity and patient risk.

Spine trial interpretation

Spine trials are highly affected by crossover, symptom severity, imaging-symptom correlation and patient preference. Quote the signal, then explain how patient selection changes the decision.

Clinical Relevance and Application

Common traps when applying landmark orthopaedic trials
The most common error is overgeneralisation. A landmark trial should anchor a decision, not replace clinical judgement.Credit: Original OrthoVellum illustration

How to State a Landmark Trial in Practice

StepGood AnswerWeak Answer
Name the questionPROFHER studied surgery versus non-operative care for displaced proximal humerus fractures in adults.PROFHER says no surgery.
Name the outcomeThe key outcome was patient-reported function, not perfect radiographic anatomy.The X-ray looks better after surgery.
Name the limitationI would still individualise younger patients, fracture-dislocations, head-splitting injuries and clear surgical indications.The trial applies to every proximal humerus fracture.
Translate to managementThis evidence supports shared decision-making and avoids routine surgery in broad low-risk groups.I quote the acronym and stop.

Evidence Base

DRAFFT distal radius fixation

Randomised trials
Key Findings:
  • DRAFFT compared K-wires with volar locking plates in adult dorsally displaced distal radius fractures.
  • DRAFFT 2 compared moulded cast with K-wire fixation after manipulation.
  • Together they discourage automatic escalation to expensive or invasive fixation for broad fracture groups.
Clinical Implication: Distal radius fixation should be individualised by stability, reduction, patient demand, bone quality and complication risk.
Limitation: Subgroups with severe instability, open injury or highly specific functional demands may not be answered fully.
Source: UK DRAFFT, 2015. PMID 25716883; DRAFFT 2, 2022. PMID 35152940

PROFHER proximal humerus

Pragmatic randomised trial
Key Findings:
  • Surgery did not show a clear patient-reported outcome advantage over non-operative treatment in the studied displaced proximal humerus fracture population.
  • The trial strongly challenged routine fixation for broad adult displaced proximal humerus fracture groups.
  • Interpretation depends on fracture pattern, patient age and exclusions.
Clinical Implication: Discuss non-operative care seriously for many proximal humerus fractures rather than presenting surgery as automatic.
Limitation: Does not answer every complex fracture-dislocation, head-splitting fracture or younger high-demand case.
Source: Rangan et al., JAMA, 2015. PMID 25756440; HTA report PMID 25822598

FLOW open fracture irrigation

International trial programme
Key Findings:
  • FLOW tested irrigation pressure and solution strategy in open fracture wounds.
  • It shifted open-fracture irrigation discussion from tradition toward evidence.
  • Soap solution became less attractive after trial signals.
Clinical Implication: Open fracture care should prioritise timely debridement, appropriate irrigation and antibiotics rather than ritualistic high-pressure lavage.
Limitation: Irrigation is only one part of open-fracture management.
Source: FLOW design and pilot papers PMID 20459600, PMID 21378581; FLOW cohort analyses

HEALTH femoral neck fracture

Randomised trial
Key Findings:
  • Compared THA with hemiarthroplasty for displaced femoral neck fracture in selected ambulatory older adults.
  • THA offered modest functional benefits but with important tradeoffs.
  • Patient selection remains central.
Clinical Implication: THA is not automatically better for every displaced intracapsular fracture; choose based on cognition, function, life expectancy, dislocation risk and local expertise.
Limitation: Selected population; frailty and surgical risk change the decision.
Source: HEALTH Investigators, NEJM, 2019. PMID 31557429

METEOR and FIDELITY

Randomised and placebo-surgery controlled trials
Key Findings:
  • METEOR supported physical therapy as a strong strategy for meniscal tear with osteoarthritis.
  • FIDELITY found no meaningful advantage of arthroscopic partial meniscectomy over sham surgery for degenerative meniscal tear.
  • Longer follow-up reinforced caution around routine degenerative meniscus arthroscopy.
Clinical Implication: Degenerative meniscal symptoms should usually start with education, rehabilitation and non-operative care.
Limitation: Locked knee, acute traumatic tears and repairable tears are different clinical questions.
Source: METEOR, NEJM, 2013. PMID 23506518; FIDELITY, NEJM, 2013. PMID 24369076; five-year follow-up PMID 32855201

KANON ACL strategy

Randomised strategy trial and follow-up analyses
Key Findings:
  • Compared early ACL reconstruction with rehabilitation plus optional delayed reconstruction.
  • Supports a structured rehabilitation-first discussion for selected ACL injuries.
  • Persistent instability, pivoting sport and meniscal risk still change the decision.
Clinical Implication: ACL treatment should be goal-based rather than automatically immediate reconstruction.
Limitation: Young pivoting athletes and recurrent instability need individualised risk discussion.
Source: KANON secondary analyses and long-term reports, including PMID 36328403

CRISTAL and EPCAT II

Randomised prophylaxis trials
Key Findings:
  • CRISTAL compared aspirin with enoxaparin after hip or knee arthroplasty.
  • EPCAT II tested aspirin after an initial rivaroxaban period.
  • The trials answer different prophylaxis strategies and should not be merged into a single aspirin rule.
Clinical Implication: VTE prophylaxis decisions need patient risk, bleeding risk, local protocol and exact trial context.
Limitation: Drug timing, patient selection and outcome definitions differ.
Source: CRISTAL, JAMA, 2022. PMID 35997730; EPCAT II, NEJM, 2018. PMID 29466159

SPORT lumbar spine trials

Trial programme and review
Key Findings:
  • SPORT evaluated surgery and non-operative care for lumbar disc herniation, stenosis and degenerative spondylolisthesis.
  • Crossover complicates interpretation but reflects real patient preference in symptomatic spine disease.
  • Surgery can benefit selected symptomatic patients when imaging and symptoms match.
Clinical Implication: Use SPORT as a patient-selection discussion, not as a blanket rule for or against spine surgery.
Limitation: Crossover and preference effects are central.
Source: SPORT literature review, 2019. PMID 31145150

Clinical Scenarios

Use these scenarios to practise clinical reasoning and management decisions

CLINICAL SCENARIOChallenging

Applying PROFHER

CLINICAL PROMPT

"An older adult presents with a displaced proximal humerus fracture. The radiograph is shown and the examiner asks whether PROFHER means surgery should never be offered."

PRACTICAL APPROACH
No. PROFHER strongly challenged routine surgery for many displaced proximal humerus fractures in adults, using patient-reported outcomes in a pragmatic trial population. I would use it to support a careful non-operative discussion, but I would still assess fracture-dislocation, head split, open injury, neurovascular status, rotator cuff status, patient age, functional demand and whether the patient resembles the trial population.
KEY CLINICAL POINTS
State the trial question.
State the practice signal.
Do not overgeneralise to excluded injuries.
Translate evidence into shared decision-making.
COMMON PITFALLS
âś—Saying PROFHER means no proximal humerus fracture needs surgery.
âś—Ignoring fracture-dislocation or head-split patterns.
âś—Not stating the primary outcome.
CLINICAL SCENARIOStandard

Degenerative meniscal tear

CLINICAL PROMPT

"A patient with degenerative meniscal symptoms and osteoarthritis asks whether arthroscopy will fix the problem."

PRACTICAL APPROACH
I would explain that METEOR and FIDELITY both make routine arthroscopic partial meniscectomy hard to justify for many degenerative meniscal tears, especially with osteoarthritis. I would start with education, exercise therapy, analgesia and activity modification. I would reserve arthroscopy for a different clinical question, such as a true locked knee, acute repairable tear or highly selected persistent mechanical symptoms after proper non-operative treatment.
KEY CLINICAL POINTS
METEOR supports physical therapy as a strong comparator.
FIDELITY challenged placebo-level benefit for degenerative tear surgery.
Acute traumatic and locked-knee scenarios are different.
COMMON PITFALLS
âś—Treating all meniscal tears as the same.
âś—Ignoring osteoarthritis.
âś—Using MRI findings alone as an operation indication.
CLINICAL SCENARIOChallenging

Arthroplasty prophylaxis

CLINICAL PROMPT

"A colleague says EPCAT II and CRISTAL prove aspirin is either always safe or never safe after arthroplasty."

PRACTICAL APPROACH
That is too simplistic. EPCAT II tested aspirin after an initial rivaroxaban period, whereas CRISTAL compared aspirin with enoxaparin in a different protocol context. They answer different prophylaxis questions. I would decide prophylaxis using patient VTE risk, bleeding risk, procedure type, local protocol and the exact timing of the drug strategy.
KEY CLINICAL POINTS
Do not merge different trial protocols.
Drug timing matters.
Risk stratification matters.
Outcomes include symptomatic VTE, bleeding and mortality.
COMMON PITFALLS
âś—Treating aspirin-only and sequential prophylaxis as identical.
âś—Ignoring bleeding risk.
âś—Quoting only one outcome.

Landmark Trials: Key Takeaways

Clinical summary

How to quote

  • •State patient group.
  • •State intervention and comparator.
  • •State primary outcome.
  • •State practice signal and limitation.

Trauma

  • •DRAFFT: distal radius fixation choices.
  • •PROFHER: proximal humerus surgery challenged.
  • •FLOW: open fracture irrigation evidence.
  • •HEALTH: THA versus hemiarthroplasty tradeoffs.
  • •FORCE: simple care for torus fracture.

Sports/Knee

  • •KANON: ACL rehab-first strategy for selected patients.
  • •METEOR: physical therapy strong for meniscus with OA.
  • •FIDELITY: degenerative meniscectomy challenged by sham trial.
  • •MOON: ACL cohort for prognosis and counselling.

Arthroplasty/Spine

  • •CRISTAL and EPCAT II answer different prophylaxis questions.
  • •SPORT supports selected spine surgery but crossover matters.
  • •Registry signals are useful but observational.

Common errors

  • •Overgeneralising.
  • •Ignoring exclusions.
  • •Forgetting the primary outcome.
  • •Treating non-inferiority like superiority.
  • •Using a trial as an automatic rule.
Study Focus
Estimated read60 min

Decision sections

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