Bike Fit Case Study, Perthes Disease

28 year old male, remains active with cycling and weight lifting. Stopped running recently due to hip issues.

History of present condition: When cycling he denies any hip or lower back pain but instead report pain in his neck and upper back which limits his cycling to one hour max.

Past medical history. Perthes disease which has caused deformity of his hip bones, specifically the shape of his greater trochanters are squared and not the normal ball shape. Therefore he reports limited range of movement in his hips and can't bend forward easily.

Perthes Disease effecting the hip joint

Gym: does get hip pain when performing dead lifts in the gym  and squatting with a weight.

Physio assessment:

• Shoulder range of movements full and power 5/5 with good muscle bulk through out.

• Thoracic and C spine full range both actively and passively with 5/5 power.

• Lumbar Spine: Standing Lumbar flexion was very limited and most of the movement was in his Thoracic spine.

• Special Tests. Passive movement of his lumbar vertebrae where stiff from L1 to L5 with pain 3/5 with higher velocity movements.

• Hip joints. In standing left Iliac cress higher than right. Range of movement limited to 90 degrees of flexion, 30 degrees of internal and external rotation for both hips. Only 90 degrees of hip flexion will make the top of the pedal stroke challenging.

• Lower limb strength was 5/5 left = right but flexibility limited to 140 degrees of extension in hamstrings.

• Leg length: Left femur is 9mm longer than right.

• Foot posture and size: equal foot and toe length. Both feet over pronate when squatting left = right

Bike Fit Initial Assessment.

• I Found he is over reaching to handle bars, causing his arms, neck and shoulders to over extend. This caused a curve in his spine due to the limited range in his lumbar spine.

• When pedalling both of his knees tracked out – which presented as a bow legged pedalling action. This was due to the limited range of movement in his hips.

Bike Fit Changes:

• Despite lowering his saddle by 9mm which optimised his quad and hamstring function, both of his knees still tracked out at the top of the pedal stroke - due to the limited ROM in his hips.

• Using the handle bar stem jig we found reducing his stem length from 100mm to 70mm resolved his neck and upper back pain.

• I also fitted high arch inner soles to stop his over pronation when cycling.

Pre Fit: Knees mal-tracking due to limited hip and lumbar mobility

Planned Bike Fit Follow Up:

• Testing his pedal stroke with an adjustable crank jig will hopefully resolve his knees tracking out. I suspect 155mm or shorter will be required.

• With to a combination of shorter cranks and stem length he should be able to pedal with his limited hip and lumbar spine range of movements and therefore avoid future injury.

• Once he has been tested with the shorter cranks I can then assess his leg length discrepancy of 9mm difference. A 9mm shim could could stabilise is pelvis as long as there are no secondary symptoms. A 5mm shim might be more tolerable.

• Once his knees track in line with pedal stroke then I can adjust his cleats to allow a more efficient in-line foot posture. This will be a far more efficient pedalling style with greater power out put.

I will update this blog with the results of the follow up session and post a video on Instagram and Facebook to show you the results.