Knee surgeon specialising in ACL reconstruction, patella stabilisation, knee replacement, arthroscopy. Researching 3D quadriceps alignment. Opinions my own
Melbourne, Australia
Joined March 2014
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Quadriceps Malalignment is the driver of patellofemoral joint imbalance. It leads to lateral patella osteoarthritis, patella dislocation, anterior knee pain and poor outcomes after knee replacement. It’s a new concept most doctors don’t know about. #knee kneesurgeonmelbourne.com.au/…
If we’re serious about understanding PFJ pathology, this needs to be part of the conversation.
I’ve put together a clear summary of the evidence, imaging methods, and concepts here:
kneesurgeonmelbourne.com.au/…
I’ll keep updating it as new data emerges.
The only way to detect this is with imaging:
→ CT or MRI
→ Direct measurement of quadriceps muscle/tendon alignment
This is a new—and controversial—concept.
But it is measurable, reproducible, and increasingly supported data
We’ve overlooked it because we haven’t been measuring it.
The Q-angle is a 2D simplification of a 3D system.
~75% of the quadriceps originates from the femur.
Ignoring that is a fundamental error.
A 3D soft-tissue deformity.
Present from birth.
This changes the direction of force across the patella—long before any arthritis develops.
It helps explain:
Lateral patellofemoral OA
Patellar instability
Anterior knee pain
Why some TKAs underperform despite “perfect” alignment
We’ve been getting the patellofemoral joint wrong
🧵
Most models treat PFJ pathology as a bony alignment problem.
TT–TG. Trochlea. Q-angle.
But these don’t explain what we actually see clinically.
The primary driver is being missed:
Congenital variation in quadriceps alignment.
Quadriceps alignment part 1 (Why the Q angle is wrong)
It is ridiculous that in this era of 3D imaging we still use the 2D Q angle as an indication of the force vector of the quads. youtu.be/PjRr-LhqeSU?si=ouYK… via @YouTube
The Q angle is wrong - a 2D line which ignores the 3/4 of the quadriceps attaching to the femur. When you measure in 3D quads alignment is much more variable and clinically relevant - maltracking, lateral patella OA, instability, TKR outcomes youtu.be/lmSEHMHkD9U?si=YzAK… via @YouTube
Simon Talbot retweeted
Quadriceps malalignment impacts TKR outcomes: Adjusting femoral component rotation >2° improves recovery and patient satisfaction in cases of preoperative maltracking.
Reach here: doi.org/10.1002/ksa.12544
Quadriceps malalignment linkedin.com/posts/mrsimonta…
The way we have been measuring the alignment of the quadriceps mechanism (the Q angle) is wrong. It doesn’t detect quadriceps malalignment due to rotation of the quads muscle attachment laterally around the femoral shaft. esskajournals.onlinelibrary.… #knee #physiotherapy #Orthopedics
Quadriceps tendon malalignment is an independent anatomical deformity which is the primary abnormality associated with lateral facet patellofemoral joint osteoarthritis - Talbot - 2023 - Knee Surgery, Sports Traumatology, Arthroscopy - Wiley Online Library esskajournals.onlinelibrary.…