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Adult Reconstruction
intermediate
X-Type

TKA Instability - Flexion Gap and Constraint Selection

TKA Complications

A 65-year-old woman presents with a sensation of "giving way" 6 months after posterior-stabilized TKA. She reports the knee feels unstable when descending stairs and occasionally buckles. Examination reveals a well-healed incision, full extension, and 125 degrees flexion. Varus-valgus stress testing shows 10mm of medial opening in extension (compared to 3mm on contralateral side) with a soft endpoint. Radiographs show well-fixed components with no evidence of loosening and acceptable alignment. Regarding instability after TKA:

Mark each as TRUE or FALSE

A

Instability is one of the most common causes of TKA revision, accounting for 10-25% of revisions; it...

B

Gap balancing in TKA aims for equal and balanced flexion and extension gaps; the extension gap is pr...

C

All cases of TKA instability require revision surgery; component position and sizing have no impact ...

D

Classification of TKA instability includes: extension instability (tight flexion gap, loose extensio...

E

Causes of instability include soft tissue imbalance (MCL or LCL insufficiency), component malpositio...

Answer the questions to see explanations

Click T (True) or F (False) for each option