APEX Knee Navigating Pearls and Pitfalls-Patellar Instability (Lateral Release, MPFL Reconstruction)

Video Transcription

Video Summary

The session covers evaluation and surgical decision-making for recurrent patellar instability using a case of a 28-year-old woman with over 10 dislocations, normal gait/alignment, positive apprehension, and minimal pain except during episodes. Faculty emphasize starting with plain radiographs (especially a true lateral) to “qualify” trochlear dysplasia using signs like the crossing sign and supratrochlear spur; sunrise views are considered more useful for assessing degeneration than instability and are highly dependent on knee flexion angle.<br /><br />All panelists obtain MRI after a dislocation—certainly with recurrent events—to assess cartilage injury, loose bodies, MPFL status, scar tissue, patella height, and trochlear dysplasia (e.g., lateral trochlear inclination). There is debate about routinely measuring TT–TG: one speaker argues elevated TT–TG often reflects external tibial rotation driven by trochlear dysplasia rather than true tubercle lateralization, so it may be a secondary “artifact” and not a strong standalone indication for tibial tubercle osteotomy.<br /><br />Treatment discussion centers on MPFL reconstruction as the main stabilization procedure; additional procedures depend on dysplasia severity (trochleoplasty for flat/convex trochlea) and selective lateral lengthening. Technical pearls stress avoiding patellar fracture (don’t violate anterior cortex; use small anchors), and getting the femoral tunnel/Schöttle’s point correct with fluoroscopy and isometry checks; overtensioning should be avoided, and pediatric tunnels must stay below the physis.

Asset Caption

Moderator: Jason L. Koh, M.D.
Panel: James Lee Pace, M.D., Nikolaos K. Paschos, M.D., Ph.D., Giovanna Medina, M.D., Ph.D., Sherwin S.W. Ho, M.D.

Keywords

recurrent patellar instability

MPFL reconstruction

trochlear dysplasia evaluation

true lateral knee radiograph crossing sign

MRI after patellar dislocation cartilage injury loose bodies

TT-TG distance tibial tubercle osteotomy debate

femoral tunnel placement Schöttle point isometry