Purpose

The purpose of this study was to better understand the natural history of post-traumatic subchondral bone marrow oedema (BME), a precursor to osteoarthritis.

We had three null hypotheses: 1) MRI appearance of the subchondral bone are unaffected by marathon running; 2) change in MRI appearance of BME is not affected by location; 3) MRI appearance of BME resolves to baseline levels by 6 months post marathon.

Methods and Materials

37 beginner runners (74 knees, median age 45) underwent 3T MRI at 3 time points in relation to a marathon: 4 months before, 2 weeks after and 6 months after.

Knees were graded using validated scoring systems. The participants completed a Knee self-assessment.

Our outcome measure was the change in radiological score of knee structure in 3.0 T MRI.

Results

Hypothesis 1: Baseline MRI revealed BME in 30 of 74 knees (41%). Immediate post-marathon MRI revealed 18 new BME lesions and 3 resolved lesions..

Hypothesis 2: Baseline MRI revealed the location of BME (Table1). Patella-femoral locations were the most resolved.

Hypothesis 3: 6-month post-marathon MRI revealed improvement in 10 of 16 knees (63%).

Conclusion

Marathon running increases BME in knees of some runners and decreases it in others.

At all time points, the patella was the most affected area of the knee.

Two thirds of all areas affected by BME had recovered / resolved by 6 months post marathon.