biomechanics of anterior knee pain ?hip dyplasia

hi everyone,

i'm a junior doc in london & i've got a query re: right knee pain when cycling. i've never done an ortho job- you guys are gonna know much more than me i reckon.....

i usually ride about 80-100 miles a week- commuting plus the odd weekend blast. this has never caused any problems. i'm increasing my miles at the moment in preparation for a ride in the alps in july- doing 50-60 mile rides and hopefully some hills soon. cadence is always above 80rpm.

i am experiencing anterior & slightly medial knee pain in right knee after cycling over 25-30 continuous miles. it lasts for a few days after the cycle and is exacerbated when walking down stairs- when weight bearing on right leg with knee flexed circa 20-30 degrees. it's also bad going up stairs but not as severe. it resolves after 2-3 days, but always returns after cycling more than 25 miles. i did have this issue a few years back on a couple of long rides, but it seemed to go- i guess as i was riding shorter distances and it's never been a problem with 10 miles x 2 in a day's commuting.

i reckon it's a patella-femoral tracking issue. as the pain is not lateral i don't think the ITB is to blame, nor a weak vastus medialis (although I suppose weak quads could play a small role). i have read about foot problems in cyclists (specifically forefoot varus causing compensatory over-pronation) causing medial knee pain. i've never had a problem with my feet off the bike so i don't think it's this.

what i have noticed is that my right hip cracks and pops now and again and there is a bit of tenderness over the joint sometimes. i filmed myself on my turbo-trainer and noticed that my right leg is deviated away from the top tube with each pedal stroke, with the right hip being externally rotated. i reckon this is externally rotating the right femur which is then placing uneven strain on the patella cartilage. the left leg doesn't veer outwards and the knee is fine.

i reckon the two possible of causes of this are: 1) weak internal rotators relative to external rotators or 2) structural deformity of hip such as hip dysplasia (my mum has had this recently Dx'ed age late 50's- it's not just in kids!)

equipment:

2004 specialized allex comp e5 slx (56cm/large) with dura-ace group 53-39 on the front/12-23 on the back. 172.5mm cranks (changing to compact for alps)

shimano spd's (not road pedals) with sidi's (fair amount of float)

bike set up with knees flexed to 10-20 degrees with pedal at 6 o'clock (happy with seat height)

knee is behind pedal axle (poss too far back?)

now the questions:

does the hypothesis above seem okay or am i missing something obvious?

anyone got any ideas on pro bike fit? is it worth it?

i'm guessing the most logical stage of Ix is pelvic x-ray + ortho review. (have already seen a physio who was very helpful are recommended some VMO exercises and ITB stretches, but i didn't mention any hip stuff to her.)

Dear Moonunit

your hypthesis sounds quite logical, why dont you test it by having someone tape your patella into good tracking then go for your bike ride...if you do not get pain as you usually would feel with the usual, then this is the problem...and you dont need anybody's advice here...

your description trully supports a patella tracking problem, especially with the stairs bit...if your femur naturally falls into external rotation, one can only imagine what is happening to the femopatellotibial alignment...

you can assess yourself

place two fingers one on each side of your patella as you long sit...try to keep your lowerlimb as straight as you can, push the back of your knee down, your patella should glide horizontal in a straight line, does yours deviate anywhere? medial, lateral?

ask a friend to hold your patella down, the push your knee down to contract your quads, the pain you feel is it similar to the ususl pain you get when you ride?

test the length of your ITB on both sides...also test the lenth of your quads and hamstrings on both sides? any difference?

you hip cracks and pops? you might have a snapping tendon there or torn cartilage? perhaps too much anterior glide in the hip with external rotation? do you have a range of motion restriction as well or range is full?

what happens with hip flexion? any pain? what happens with resisted hip flexion? now what happens with a downward pressure on the anterior hip with hip flexion? any pain increase or decrease?

there are specific exercises to manage these problems

snapping and popping is unlikely to show anything on xray because it sounds soft tissuey...go for an MRI instead , how old are you though?

cheers

if there is a problem with ur "Q" angle of Knee Joint , it may the cause of ur discomfort, check this . Then there may be a permanent solution for u.

Let's not forget about synovial plica as a common cause of medial knee pain in cyclists, often misdiagnosed as PF syndrome.