Femoral Neck Growth and Remodeling With Free-Gliding Screw Fixation of Slipped Capital Femoral Epiphysis
Bibliographic record
Abstract
BACKGROUND: Treatment of stable slipped capital femoral epiphysis (SCFE) most commonly involves in situ fixation with a standard cannulated screw, leading to physeal arrest. Recently, Pega Medical (Laval, Canada) introduced the free-gliding (FG) SCFE screw, which employs a growth-friendly, telescopic design. This study examines femoral neck growth and remodeling over the first 2 postoperative years in stable SCFE treated with FG versus standard screws. METHODS: We retrospectively reviewed 32 hips (19 SCFE, 13 prophylactic) in 16 patients treated with FG screws for stable SCFE. We also reviewed 102 hips (63 SCFE, 19 prophylactic, 20 controls) in 55 patients treated with standard screws. Immediate postoperative radiographs were compared with 1- and 2-year follow-up images. RESULTS: For the overall study cohort, mean age at surgery was 12.2±1.9 years, with a mean slip angle of 26.9±18.0 degrees. In FG SCFE hips, the alpha angle remodeled 12.9±19.2 degrees in the first postoperative year (P=0.018) and articulotrochanteric distance decreased by 4.2±4.6 mm at 2 years (P=0.018). In standard SCFE hips, the alpha angle remodeled 4.3±11.3 degrees at 1 year (P=0.014), while articulotrochanteric distance decreased by 4.5±3.2 mm at 2 years (P<0.001). By 2 years, FG screws lengthened more in prophylactic (4.8±3.4 mm) than SCFE hips (1.7±1.8 mm, P=0.027). CONCLUSIONS: Greater remodeling of femoral neck cam deformity occurs when treating SCFE using an FG screw. Further research is required to measure the impact of this finding on femoroacetabular impingement and degenerative arthritis. In addition, FG screws allow ongoing growth of prophylactically treated hips, while standard screws promote coxa breva. LEVEL OF EVIDENCE: Level III-retrospective comparative, therapeutic study.
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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 | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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) | 0.001 | 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".