Sagi (2012) — The functional consequence of syndesmotic joint malreduction at a minimum 2-year follow-up.

The Functional Consequence of Syndesmotic Joint Malreduction at a Minimum 2-Year Follow-Up.

·J Orthop Trauma·2012·466 citations·Trauma

Prospective cohort study from a Level I trauma center asking whether CT-confirmed syndesmotic malreduction after operative ankle fracture fixation translates to worse patient function. 68 patients underwent bilateral CT and validated functional outcome scoring at minimum 2 years. The central question: does malreduction invisible on plain films actually hurt the patient?

Study Snapshot

Design

Prospective cohort

Setting: Single Level I regional trauma center

Funding: None

Objective

Whether CT-confirmed syndesmotic malreduction correlates with worse functional outcome at 2 years.

Outcome(s)

SMFA and Olerud/Molander scores at minimum 24 months

Subjects

68 patients with syndesmotic ankle fractures

13Open syndesmotic reduction
55Closed/indirect syndesmotic reduction

Inclusion

Skeletally mature patients
Closed, isolated, unilateral ankle injury
Syndesmotic reduction required at time of ORIF

Exclusion

Diabetes or peripheral neuropathy
Pre-existing ankle arthritis
Prior trauma to either ankle

Follow-up

Minimum 2 years

Statistics

Fisher exact testMann-Whitney U test

Key Findings

39% of syndesmoses (27/68) were malreduced on postoperative CT despite looking anatomic on every plain radiograph and intraoperative fluoroscopic image. This is the defining finding of the paper: fluoroscopy simply cannot be trusted to confirm syndesmotic reduction.
Malreduction produced significantly worse scores on both validated outcome instruments at 2 years:
–SMFA Functional Index: malreduced 27.0 vs anatomic 12.0 (P < 0.05; higher = worse)
–Olerud/Molander: malreduced 46.3 vs anatomic 72.7 (P < 0.05; lower = worse)
–This is the first study to directly tie CT-confirmed malreduction to worse patient-reported function.
Open direct visualization cut the malreduction rate from 44% to 15% (P = 0.11). The p-value missed significance only because the open group contained 13 patients — the absolute difference is clinically decisive. Release the extensor retinaculum and look at the joint.
The most common malreduction pattern was fibular lateralization with AP translation (64% of malreductions). Rotational malreduction accounted for 28%, split equally between internal and external rotation. The remainder involved combinations of translation, malrotation, and shortening.
Two distinct normal syndesmotic morphologies exist on CT:
–Type A: flat, vertical, and shallow
–Type B: concave and cup-shaped
–Because of this variation, a single-sided measurement threshold is inherently unreliable. Bilateral CT with contralateral comparison is the only valid assessment method.
Even open direct visualization is not foolproof: 2 of 13 openly reduced syndesmoses remained malreduced on CT, both from internal rotation of the lateral malleolus. Postoperative CT remains necessary even after open reduction.

Board PearlSyndesmotic malreduction invisible on fluoroscopy occurs in 39% of cases and directly causes significantly worse functional outcomes at 2 years.

Clinical Relevance

Gardner et al. (2006) showed CT malreduction rates as high as 52%, but without functional consequence data that finding lacked clinical teeth. Sagi (2012) provided exactly that: a direct, statistically significant link between CT-confirmed malreduction and worse patient-reported function at 2 years on two validated instruments.

When you fix a syndesmotic injury, do not trust the fluoroscope. Release the extensor retinaculum and directly visualize the anterior syndesmotic joint — open reduction cuts malreduction risk from 44% to 15%. Then get a postoperative CT of both ankles and compare sides, not to a population threshold, because Type A and Type B morphologies mean a universal reference range does not exist.

If the CT shows malreduction, take the patient back. The outcome data justify both the scan and the revision.

The Functional Consequence of Syndesmotic Joint Malreduction at a Minimum 2-Year Follow-Up.

Study Snapshot

Key Findings

Clinical Relevance

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The Functional Consequence of Syndesmotic Joint Malreduction at a Minimum 2-Year Follow-Up.

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The Functional Consequence of Syndesmotic Joint Malreduction at a Minimum 2-Year Follow-Up.

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The Functional Consequence of Syndesmotic Joint Malreduction at a Minimum 2-Year Follow-Up.

Study Snapshot

Key Findings

Clinical Relevance

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