Classic Versus Congruent Coracoid Positioning During the Latarjet Procedure: An In Vitro Biomechanical Comparison
Bibliographic record
Abstract
PURPOSE: The purpose of this biomechanical study was to compare the classic Latarjet technique and congruent-arc modification with respect to glenohumeral stability, joint stiffness, translation, and range of motion. METHODS: Eight cadaveric forequarters were tested on a shoulder simulator that applied loads independently to the conjoint tendon, long head of biceps, rotator cuff, and deltoid. The test conditions included: intact, 30% glenoid defect, and reconstruction of the defect with the classic and congruent Latarjets. The Latarjet techniques were randomly ordered, with the outcome variables being anterior dislocation, glenohumeral translation, rotational range of motion, and joint stiffness. RESULTS: All 8 specimens dislocated after creation of a 30% glenoid defect. The classic Latarjet stabilized 7 of 8 specimens, whereas the congruent-arc modification stabilized all specimens (8/8). In abduction neutral rotation, there was no difference in joint translation between techniques (P = .613). In abduction external rotation, there was significantly greater anterior humeral head translation after the congruent technique than after the classic (9.9 and 6.5 mm, respectively, P = .013). Rotational range of motion was significantly reduced after classic (-25.8°) and congruent (-22.2°) transfers as compared with the 30% defect (P ≤ .041). Joint stiffness in the abducted, externally rotated position was significantly reduced in the 30% defect as compared with intact (P = .012), congruent (P = .015), and classic (P < .001) conditions. In all abduction positions, the intact was not significantly different from the Latarjet techniques, and the techniques did not significantly differ from each other (P ≥ .102). CONCLUSIONS: The classic and congruent-arc Latarjet techniques restore shoulder stability and motion in cases of considerable bone loss. The techniques do not substantially differ in rotational range of motion or joint stiffness. The congruent-arc technique, however, does result in significantly greater anterior humeral head translation, as compared with the classic technique, before reaching a stable non-dislocated endpoint. CLINICAL RELEVANCE: On the basis of this biomechanical model, both the classic and congruent-arc Latarjet techniques can be used to stabilize a shoulder with substantial glenoid bone loss. Further clinical and biomechanical studies are required to determine if particular clinical circumstances exist where 1 technique has an advantage over the other.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".