Notch impingement is when a cruciate ligament graft is wrongly placed or too bulky, and the fibres impinge on the roof of the bony notch of the femur.

Page updated January 2024 by Dr Sheila Strover (Clinical Editor)

normal femoral notch
cyclops lesion obstructing notch
cyclops lesion obstructing extension


Notch impingement and the Cyclops Lesion

Impingement may prevent the knee from straightening fully, and sometimes the impinging bit bunches up into a lump called a 'cyclops lesion' which can also add a 'clunk' as the person forces the knee into extension (ie straight). Eventually it may become impossible to fully extend the knee.

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Dr Sheila Strover (Editor)
BSc (Hons), MB BCh, MBA

See biography...



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