Influence of Risky Pathoanatomy and Demographic Factors on Clinical Outcomes After Isolated Medial Patellofemoral Ligament Reconstruction: A Regression Analysis
Bibliographic record
Abstract
Background: Multiple studies have demonstrated that a number of demographic and pathoanatomic characteristics are associated with patellofemoral instability, recurrence of instability, and less satisfactory results following medial patellofemoral ligament reconstruction (MPFL-R). Despite the growing volume of research, the relationship of risk factors to patient-reported outcome after MPFL-R is unclear. Purpose: To determine if certain pathoanatomic and demographic factors predict disease-specific quality-of-life outcome after isolated MPFL-R for symptomatic patellofemoral instability. Study Design: Cohort study; Level of evidence, 3. Methods: The study analyzed 224 isolated MPFL-Rs. Demographic data were collected, including age at first dislocation, sex, and presence of bilateral instability. Pathoanatomic risk factors included the presence of high-grade trochlear dysplasia, tibial tubercle–trochlear groove (TT-TG) distance, patella alta ratio, Beighton score, and patellar tilt. Other factors included femoral tunnel position accuracy and WARPS/STAID score. Descriptive analyses were conducted, followed by calculation of individual Spearman rank correlation coefficients for the predictor variables versus the Banff Patellofemoral Instability Instrument (BPII) scores. A multivariable regression with stepwise selection was employed to establish the final model predicting BPII score, with all significant variables for alpha ≤ .05 included in the final model. Results: The cohort of 224 patients included 66 (29.5%) males and 158 (70.5%) females, with a mean age of 24.1 years and a mean body mass index of 23.9 kg/m 2 . The mean age of first patellar dislocation was 15.7 years, and 41.4% of patients had bilateral instability. Pathoanatomic variables within the cohort included the following: high-grade trochlear dysplasia = 41%; mean TT-TG = 14.6 mm, with 16.8% of patients demonstrating a TT-TG ≥18 mm; mean Caton-Deschamps ratio = 1.09, with 22% of patients demonstrating a ratio ≥1.2; and positive Beighton score = 37.5%. The mean BPII score at postoperative 2 years was 67.1 out of 100. A stepwise elimination in the regression model demonstrated no statistically significant 3- or 2-way relationships. Assessment of individual variables indicated that bilateral symptoms ( P = .004), higher age at first dislocation ( P = .024), and femoral tunnel position >10 mm from the Schöttle point ( P = .042) were statistically significant predictors of lower quality-of-life scores. The R 2 value for the regression analysis model was 0.07. Conclusion: In this large cohort of patients undergoing isolated MPFL-R for symptomatic lateral patellofemoral instability, a multivariable forward stepwise regression demonstrated that bilateral symptoms, femoral tunnel position, and age at first dislocation were statistically significant predictors of lower postoperative BPII scores. No anatomic risk factors were predictive of quality-of-life outcome score 2 years after MPFL-R surgery. The R 2 value indicated that there were many other important contributing factors affecting BPII outcome scores than those explored in this 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 | 0.003 | 0.009 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.002 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".