Uwe Hans-Werner Schuetz MD, Abstract Co-Author: Nothing to Disclose

Christian Billich, Presenter: Nothing to Disclose

Running two marathons a day for 10 weeks is an immense load for the joints of limbs and feet. Little is known about longitudinal physiological behaviours and adaption mechanisms of the different cartilage layers regarding such a running burden. Using T2*-mapping technique on a mobile MRI truck during TransEurope FootRace (TEFR09) on ultra-runners being repeatedly examined, this lack could be closed with this field study.

TEFR09 from South-Italy to North Cape was accompanied with a mobile MRI (1,5T, Siemens) on a Truck-Trailer (39tons) through 6 countries. During race, each of 22 subjects (21 m , 1 f) got 6 whole body MRI scans (interval: 1.000 km); T2* GRE (StarMap FLASH) tra/sag (FA 60°, TE 4.3ms, TR 889-1120ms, ST 3mm, pixel size 0.33/0.42). Image postprocessing was performed by manual segmentation of cartilage surfaces in segments and layers, depending on anatomy. Mean t2 signal intensity (SI) and segment size were documented, and a T2* map of every joint could be developed and statistical analysis be done regarding different influence factors.

During the first 2.000km there was a significant SI increase in the upper layers of femorotibial and femoropatellar cartilage surfaces in all subjects detectable. For the deep layer this could not be shown. During second half of race, the amount of increase went down, significantly. The same results we got for ankle and some hindfoot cartilages, where layer separation was not possible. No significant difference regarding cartilage thickness could be shown in any joint examined. Side differences on SI amount could be recognized regarding dynamic and total data, but with no statistical tendency. 6 months after TEFR09, there was total recovery of T2* SI.

For trained ultra athletes a transcontinental race has no harmful influence on cartilage of the limbs. Depending on their adaption over years of training, their symmetric limb alignment and perfected individual running style, the joint cartilage of the limbs is no limiting factor regarding running distance. But this unique selection of subjects is answering to this exceptional running burden with an additive physiological adaption of cartilage metabolism, also. This results show, that, running is a protective factor for joint cartilages of the limbs.

Joint cartilage shows an impressive rapid regeneration ability after long-distance running, to ensure weeks of running burden.

Schuetz, U, Billich, C, Changes of Cartilage Surface in Knee, Ankle, and Hindfoot Joints in Ultra-endurance Runners during 4.487 km Trans Europe Foot Race Measured by Mobile MRI on a Truck.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11014453.html