Cast immobilisation versus surgery for unstable lateral malleolus fractures (SUPER-FIN): randomised non-inferiority clinical trial.
Kortekangas T, Lehtola R, Leskelä HV, Taimela S, Ohtonen P, Savola O, Järvinen TLN, Pakarinen H
- DOI
- 10.1136/bmj-2025-085295
- Record issued
- 2026-08-15
- Engine
- 7.39.0
- Exported
- 2026-09-22
Prepared by Alpha1. This document is confidential: it is intended for the recipient it was shared with and must not be redistributed. The live record at alpha1science.com/verify/51bd3bf8-e6c4-42ba-903b-f5edf1dccc0e is authoritative.
How this rating was calculated
- ReportingData & code availability partially met−0.25★
- No reported statistical tests were found to recompute.
- No data or code availability links were detected to verify.
This Kaimen Rigor review uses Kaimen Rigor reviewers trained on a curated corpus of high-fidelity and retracted papers, with expert supervision and curation. It can still make mistakes; verify each finding against the source before relying on it.
This is a well-conducted and transparently reported randomized non-inferiority trial. The main methodological strength is the rigorous design with proper randomization, sample size calculation, and adherence to CONSORT. The primary weakness is the incomplete data availability statement, which lacks a concrete access route for data and code.
Both reviewers independently scored all eight dimensions and agreed on every status. The study is an interventional trial; no computational or animal-model components apply. The statistics verification component checked 0 tests (none were machine-verifiable), so statistical correctness beyond the reported methods is not independently confirmed.
Numerical inconsistencies
None foundValues that contradict each other or are impossible for the stated sample: recomputed p-values and test statistics, GRIM/GRIMMER checks on summary numbers, percentages against their own counts, totals against their parts, and estimates against their own confidence intervals.
Checked — nothing surfaced.
Overstated conclusions
1 finding · worst lowConclusions that reach past what the paper's own results support — including a significance claim that no longer holds when the statistic is recomputed, and efficacy resting on an unvalidated surrogate endpoint.
- Conclusions only partially backed by the presented evidenceAssessed
5 major claims checked against the paper's own evidence: 1 only partially supported (evidence backs part of the claim; gaps or caveats remain); the rest adequately supported.
- partialReviewer 1The findings support the concept that treatment should focus on maintaining a congruent mortise using the most conservative means possible.The trial supports non-inferiority of casting, but the broader claim about treatment philosophy is an extrapolation from the results and other studies.Evidence: Discussion synthesizes findings with other trials and guidelines.
“Together, our findings and those of previous studies show that a standard below-the-knee cast provides adequate stabilisation of an isolated unimalleolar fibular fracture with a congruent ankle mortise.”
DiscussionFind in source - supportedReviewers 1, 2Cast immobilisation is non-inferior to surgery for the primary outcome (OMAS at two years).The primary analysis shows a mean difference of 1.3 points with a 95% CI of -4.8 to 7.3, and the lower limit is above the non-inferiority margin of -8.Evidence: Primary outcome result: mean OMAS 89 vs 87, difference 1.3 (95% CI -4.8 to 7.3).
“In the primary intention-to-treat analysis of 121 participants completing two year follow-up, the mean OMAS was 89 in the cast immobilisation group and 87 in the surgery group (between group mean difference 1.3 points, 95% confidence interval −4.8 to 7.3).”
AbstractFind in source - supportedReviewer 1Fewer treatment-related harms occurred with cast immobilisation compared with surgery.The results list adverse events in the surgery group (wound infection, delayed healing, hardware removal) and only one non-union in each group, supporting fewer harms with casting.Evidence: Adverse events reported: one non-union in each group; surgery group had additional complications.
“In the surgery group, one participant had a superficial wound infection, one had delayed wound healing, and nine underwent procedures to remove hardware, two of whom developed postoperative infections (one deep and one superficial).”
AbstractFind in source - supportedReviewers 1, 2No statistically significant between-group differences were observed in any secondary outcomes.The results state that no statistically significant differences were observed, and the table shows CIs that all cross zero.Evidence: Secondary outcomes table shows all CIs include zero.
“No statistically significant between group differences were observed in any secondary outcomes.”
AbstractFind in source - supportedReviewer 2Fewer treatment related harms occurred with cast immobilisation compared with surgery.The results list adverse events in the surgery group (wound infection, delayed healing, hardware removal) and only one non-union in each group, supporting fewer harms with casting.Evidence: Treatment related adverse events section lists complications in surgery group; cast group had only one non-union.
“Overall, fewer treatment related harms occurred with cast immobilisation compared with surgery.”
ConclusionFind in source
Efficacy claim is anchored to an adequate endpoint and a meaningful effect.
- ADEQUATESurrogate endpointThe primary outcome is the Olerud-Molander Ankle Score (OMAS), a validated patient-reported outcome measure for ankle fracture symptoms, which is a clinical outcome rather than a surrogate biomarker. The paper also reports hard clinical outcomes such as fracture union and adverse events. Therefore, the efficacy claim is based on a clinical outcome, not a surrogate.
“The primary outcome was the Olerud-Molander Ankle Score (OMAS) at two years. OMAS is a validated, condition specific, patient reported outcome measure for ankle fracture symptoms (range 0-100; higher scores indicating better outcomes and fewer symptoms; minimal important difference 12 points).”
- ADEQUATEEffect sizeThe primary outcome shows a between-group difference of 1.3 points (95% CI -4.8 to 7.3) on the OMAS, which is well below the minimal important difference of 12 points and the non-inferiority margin of -8 points. The effect size is anchored to clinical meaningfulness through the predefined non-inferiority margin and the minimal important difference, and the conclusion of non-inferiority is based on the confidence interval excluding a clinically meaningful benefit in favor of surgery.
“In the primary intention-to-treat analysis of 121 participants completing two year follow-up, the mean OMAS was 89 in the cast immobilisation group and 87 in the surgery group (between group mean difference 1.3 points, 95% confidence interval −4.8 to 7.3).”
Data authenticity concerns
None foundAn adversarial read for patterns associated with data that may not be genuine: results that look too clean, implausibly large effects, duplicated data or images, and methods that do not match the results reported.
Checked — nothing surfaced.
Reporting gaps
1 finding · worst mediumRequired detail the manuscript never states — study design, biological variables, ethics approval and consent, key resources, statistical reporting, data and code availability, and overall transparency.
- Data/code availability incompleteAssessed
The introduction cites prior research on ankle fracture management, including a previous randomized trial by Sanders et al., and discusses the heterogeneity in surgical rates. The rationale for the trial is clearly linked to the diagnostic challenge of occult incongruency and the need for a non-inferiority comparison. Limitations of prior research, such as the composite outcome in Sanders et al., are explicitly discussed.
“We are aware of only one randomised trial to date that has compared surgery with cast immobilisation in patients with radiographically congruent Weber B fractures classified as unstable by external rotation testing.”
“The authors’ decision to recommend surgery on the basis of a composite outcome (compromised fracture healing), a construct that has not subsequently gained widespread acceptance, likely reflects a cautiousness rooted in the longstanding concern within orthopaedics that even minor deviations in anatomy or fracture healing may increase the risk of poor functional outcomes and post-traumatic osteoarthritis.”
“We are aware of only one randomised trial to date that has compared surgery with cast immobilisation in patients with radiographically congruent Weber B fractures classified as unstable by external rotation testing.”
“The authors’ decision to recommend surgery on the basis of a composite outcome (compromised fracture healing), a construct that has not subsequently gained widespread acceptance, likely reflects a cautiousness rooted in the longstanding concern within orthopaedics that even minor deviations in anatomy or fracture healing may increase the risk of poor functional outcomes and post-traumatic osteoarthritis.”
Randomization used sequentially numbered, opaque, sealed envelopes with random permuted blocks and a computerised random number generator. Blinding of participants and assessors was not possible, but a blinded data interpretation scheme was used. A priori sample size calculation was performed with a non-inferiority margin of 8 points. Inclusion/exclusion criteria are explicitly listed. Outlier handling is addressed through intention-to-treat and per-protocol analyses. Controls are inherent in the comparator arm. Independent replication is not applicable for a single pivotal trial.
“A statistician with no clinical involvement in the trial prepared sequentially numbered, opaque, sealed envelopes with random permuted blocks (block size known only by the statistician) and no stratifications using a computerised random number generator.”
“Blinding of participants and outcome assessors was not possible owing to the nature of the interventions. However, we interpreted the results of the trial according to a blinded data interpretation scheme, to which we made minor refinements.”
“Assuming α=0.05, power 80% (1−β=0.8), and accounting for a 20% dropout rate, the required sample size was calculated to be 63 participants in each group (total n=126).”
“A statistician with no clinical involvement in the trial prepared sequentially numbered, opaque, sealed envelopes with random permuted blocks (block size known only by the statistician) and no stratifications using a computerised random number generator.”
“Blinding of participants and outcome assessors was not possible owing to the nature of the interventions. However, we interpreted the results of the trial according to a blinded data interpretation scheme, to which we made minor refinements.”
“Assuming α=0.05, power 80% (1−β=0.8), and accounting for a 20% dropout rate, the required sample size was calculated to be 63 participants in each group (total n=126).”
Sex is reported in baseline characteristics (men and women). Age is reported as mean (SD) and range. Demographics include smoking status, education level, and injury setting. Species/strain and housing conditions are not applicable for a human trial.
“Men | 34 (56) | 38 (60) | | Women | 27 (44) | 25 (40)”
“Mean (SD) age at fracture (years), (range) | 46 (18), (19-83) | 43 (19), (16-82)”
“Men | 34 (56) | 38 (60) | | Women | 27 (44) | 25 (40)”
“Mean (SD) age at fracture (years), (range) | 46 (18), (19-83) | 43 (19), (16-82)”
“Smoking status: | | Non-smoker | 34 (56) | 29 (46) | | Former smoker | 9 (15) | 3 (5) | | Current smoker | 8 (13) | 22 (35)”
The trial was approved by the institutional review board of Oulu University Hospital (EC 25/2012). All participants gave written informed consent. The study was conducted in accordance with the Declaration of Helsinki. Regulatory compliance is stated.
“The trial protocol was approved by the institutional review board of Oulu University Hospital (EC 25/2012) and has been published.”
“All participants gave written informed consent.”
“This study was conducted in accordance with the Declaration of Helsinki and was approved by the institutional review board of Oulu University Hospital (EC 25/2012).”
“This study was conducted in accordance with the Declaration of Helsinki and was approved by the institutional review board of Oulu University Hospital (EC 25/2012).”
“All participants gave written informed consent.”
The trial compares cast immobilisation with surgery (open reduction and internal plate fixation). The surgical procedure is described in detail, including the type of fixation and postoperative care. The cast immobilisation is also described. Statistical software (IBM SPSS Statistics version 25 or higher) is identified. No other key biological or chemical resources are used.
“Surgery involved internal fixation, conducted according to standard principles for ankle fracture fixation (see supplementary appendix 1, table 2).”
“The data were analysed using IBM SPSS Statistics version 25 or higher.”
“Surgery involved internal fixation, conducted according to standard principles for ankle fracture fixation (see supplementary appendix 1, table 2).”
“The data were analysed using IBM SPSS Statistics version 25 or higher.”
The primary analysis used Student's t test, and sensitivity analyses used ANCOVA. Secondary outcomes used t tests or Welch's t test, and categorical variables used chi-square or Fisher's exact test. Effect sizes are reported with 95% CIs. Exact p-values are not reported for primary outcome (only CI), but this is acceptable as the trial reports by estimation. Statistical software is identified. Data presentation includes per-group n and SDs. Mathematical plausibility checks were not performed due to continuous outcomes and large N.
“The primary analysis used Student’s t test.”
“between group mean difference 1.3 points, 95% CI −4.8 to 7.3”
“The data were analysed using IBM SPSS Statistics version 25 or higher.”
“the mean OMAS at two years was 89 in the cast immobilisation group and 87 in the surgery group (between group mean difference 1.3 points, 95% CI −4.8 to 7.3)”
“Olerud-Molander Score (0-100)* | 60 | 89 (17) | 61 | 87 (16) | 1.3 (−4.8 to 7.3)”
The data availability statement says 'The data underlying the primary findings in this paper and the code used' but is cut off and does not specify a repository or access procedure. This is reported_but_inadequate. No repository deposit or accession numbers are provided. Code sharing is not mentioned.
“The data underlying the primary findings in this paper and the code used”
“The data underlying the primary findings in this paper and the code used”
The trial is registered at ClinicalTrials.gov (NCT01758796). The reporting follows CONSORT guidelines. All outcomes are reported, including secondary outcomes and adverse events. Limitations are discussed in detail. Conclusions are proportional to the evidence. Funding and competing interests are declared.
“Trial registration ClinicalTrials.gov NCT01758796 .”
“The reporting of this study follows the Consolidated Standards of Reporting Trials (CONSORT) guidelines for non-inferiority trials.”
“Regarding limitations, single centre trials conducted by experts (here, investigators with extensive track records in studying ankle fractures ) are typically believed to enhance internal validity at the expense of external validity (generalisability).”
“Trial registration ClinicalTrials.gov NCT01758796 .”
“The reporting of this study follows the Consolidated Standards of Reporting Trials (CONSORT) guidelines for non-inferiority trials.”
Registered (1 ID: ClinicalTrials.gov). Reporting guideline cited: CONSORT.
Broken references and links
None found · partly checkedReferences checked against Crossref, OpenAlex and Retraction Watch for retractions and resolvability, plus declared data and code links probed for whether they resolve to content matching the paper.
Nothing surfaced — but not everything feeding this category ran (missing: data/code link verification), so read this as a partial clean bill.
Checked 52 references by DOI: 48 verified — 4 no DOI (shown, not verified).
- NO DOIThe Management of Ankle FracturesNo DOI in the reference — shown for manual review; not independently verifiable (not a fabrication signal).
- NO DOIFractures of the lower extremityNo DOI in the reference — shown for manual review; not independently verifiable (not a fabrication signal).
- NO DOIRAND-36 terveyteen liittyvän elämänlaadun mittarina: mittarin luotettavuus ja suomalaiset väestöarvot (The RAND-36 as a measure of health-related quality of life: validity of the instrument and normative data for Finnish population [In Finnish])No DOI in the reference — shown for manual review; not independently verifiable (not a fabrication signal).
- NO DOIMeasurement of joint motion: a guide to goniometryNo DOI in the reference — shown for manual review; not independently verifiable (not a fabrication signal).
Copyediting
5 minorWording, consistency and formatting errors that need correcting before submission.
No major wording or formatting errors. 5 minor suggestions below.
5 copyedit issues flagged: mostly consistency, clarity, typo.
- MINORtypoAbstract, Results“121 out of 126 randomised participants (96%) completed the study.”→ Consider rephrasing to 'Of 126 randomised participants, 121 (96%) completed the study.'Minor style improvement.
- MINORconsistencyResults, Recruitment“Of the 840 patients assessed for eligibility, 687 patients were excluded as non-eligible and 27 eligible patients declined to be randomised”→ Ensure the numbers add up: 687 + 27 = 714, but 840 - 714 = 126, which matches the randomised number. This is consistent.No issue.
- MINORclarityData availability statement“The data underlying the primary findings in this paper and the code used”→ Complete the sentence with a full stop and specify the access route.Incomplete sentence.
- MINORconsistencyAbstract, Participants“714 participants were excluded (569 with stable fracture, mortise incongruency, or fracture dislocation)”→ Verify the number 714 vs 687 in Results; ensure consistency.Abstract states 714 excluded, but Results states 687 excluded as non-eligible and 27 declined, totaling 714. This is consistent, but the phrasing could be clearer.
- MINORclarityData availability statement“The data underlying the primary findings in this paper and the code used”→ Complete the sentence with a concrete access route.The statement is incomplete.
The published work is robust and well-reported; an informed reader should weigh the minor data-availability gap and the fact that no reported statistics were independently recomputed. No erratum is warranted for the rigor dimensions, but completing the data availability statement would improve transparency.
- 1.HIGHdata codeComplete the data availability statement in the 'Data availability statement' section to specify a concrete access route (e.g., a repository like Zenodo or a managed-access procedure via the corresponding author).The current statement is an incomplete sentence and does not tell readers how to obtain the data or code, undermining reproducibility.
- 2.HIGHdata codeDeposit de-identified participant data in a public repository (e.g., Dryad, Zenodo) with a DOI, or state a managed-access procedure with conditions and timeframe.A repository deposit or clear managed-access mechanism is needed to make the data availability statement actionable.
- 3.HIGHdata codeShare the analysis code in a public repository (e.g., GitHub) with a permanent identifier, and describe the workflow in sufficient detail.Code sharing is not mentioned; providing it would enhance reproducibility and transparency.
- 4.MEDIUMcopyeditRephrase the abstract sentence '121 out of 126 randomised participants (96%) completed the study.' to 'Of 126 randomised participants, 121 (96%) completed the study.'Minor style improvement for clarity.
- 5.MEDIUMcopyeditClarify the exclusion numbers in the Abstract and Results to ensure consistency (e.g., state that 687 were non-eligible and 27 declined, totaling 714).The current phrasing could confuse readers about the exact breakdown of exclusions.
- 6.LOWcopyeditAdd a full stop to the data availability statement sentence and complete it with the access route.The sentence is grammatically incomplete.
The star rating is the report’s one-glance summary. Every paper starts at 5★ and loses stars for the concrete problems the review finds — so a rating is never a vague average, it’s a running total you can read line by line under “How this rating was calculated.”
- Reporting — 8 dimensionseach dimension that fully fails−½★
- each dimension partially met−¼★
- Statistics · Integrity · Claimseach serious problem−1★
- each medium problem−½★
- Citationseach retracted or unverifiable reference−¼★
- Copyeditonly when the manuscript needs a full edit−½★
The rating never drops below 1★, and a demonstrable critical failure (an impossible statistic, a proven ethics violation) caps it at 1★ on its own — so the stars can never look healthy when the verdict is CRITICAL.
The rating draws on a panel of agents. Three independent Kaimen Rigor reviewers grade the eight dimensions below across several independent passes (the shown verdict is their majority vote — steadier than any single run), isolate the paper’s major claims and check its own evidence backs them, and flag integrity concerns. Alongside them, a citation agent resolves every reference against Crossref, OpenAlex, and Retraction Watch; a statistics agent recomputes reported tests; and rule-based checks verify that declared data/code links actually resolve. Full text is required — an abstract-only submission is not analyzed.
Graded against NIH, MDAR, ARRIVE 2.0, CONSORT, EQUATOR, and RRID guidelines. A dimension that doesn’t apply to the study type is skipped, never penalized.
This Kaimen Rigor review is model-assisted and is not a substitute for formal expert review. It complements human evaluation by surfacing potential methodological concerns — verify each finding against the source.