Windshield wiper syndrome

Windshield wiper syndrome is exertional pain on the outer side of the knee that rises more or less upwards on the lateral side of the thigh and specifically  affects long-distance runners, cyclists , tri-athletes and lovers of mountain running (trail).

This pain corresponds to a tendino-bursitis   of the posterior edge of the very thick ilio-tibial fibrous band  which comes into conflict with the external condyle of the lower end of the femur.

This fibrous strip positioned forwards when the knee is extended, slides backwards like a windshield wiper, knee flexed and  the repetition of the movement will create painful friction against the external condylar relief.

Windshield wiper syndrome preferentially affects runners and tri-athletes 

Intrinsic contributing factors:

excessive protrusion of the external femoral condyle genu varum unequal length of the lower limbs

hyper-pronator foot. 

Extrinsic contributing factors

- technological:  unsuitable or worn shoes for long-distance runners, particular ground (curved road), poor adjustment of the pedals. - dystraining:  excess and above all sudden increase in weekly mileage , training uphill and downhill,  neglected stretching.
The diagnosis is essentially clinical. The pains of effort are localized on the level of the external part of the knee and radiate  along the external face of the thigh. They are of progressive installation only appearing after a few kilometres, favored by hilly terrain or flat, non-hard surfaces. The pain increases when the effort intensifies and the mileage increases. Once installed, the pain does not disappear when the effort is stopped (stage 3 of Blazina).

Palpation of the posterior surface of the external condyle produces exquisite pain . Knee examination is normal: patella, menisci, external collateral ligament, pivot; no patellar shock, no pain on  palpation of the joint spaces in search of chondropathy, no laxity in varus, no abnormal mobility.

The upper fibula-tibial joint is free. 
Two clinical tests confirm the diagnosis:  
- the Renne test:  weight-bearing and mono-pedal support:  
appearance of pain when performing  flexion/extension movements of the knee.

- the Noble test: subject in dorsal or lateral decubitus:

if digital pressure is exerted, knee flexed at 90°, at the level of the top of the external condyle, 2 to 3 cm above the joint space and passively extending the knee while maintaining the tibia in varus and internal rotation by the mobilizing hand; a sharp pain appears around 30° of flexion, indicating the positivity of the test.

departure 

arrival 

Imaging  is useless and the differential diagnosis is easy (strictly normal knee examination) with external meniscal syndrome, blockage of the upper fibula-tibial joint, stress fracture of the neck of the fibula in runners, femoral chondropathy -external tibial.

Treatment  in the acute phase:  essentiallymedical: relative rest, ice, analgesics, NSAIDstransversemassage  and stretching), physiotherapy.

Treatment in  the chronic phase  (stage 3 of Blazina), total rest and 1 to 2 tendinobursitis infiltrations can solve the problem.

Exceptional surgical treatment  (Jager, Lutz), in the event of failure of medical treatment : excision of the bursitis, regularization of the posterior face of the external condyle, lengthening plasties of the ilio-tibial band. 

Prevention:  stretching, running shoes adapted and replaced regularly, adjustment of the pedals... , plantar orthosis if the foot pronator.

For runners, you have to pay attention to the nature of the terrain and training can be resumed gradually when the stretching of the strip has become painless.