Do knees survive the Comrades Marathon?

Area of Science:

• Sports Medicine
• Radiology
• Orthopedics

Background:

• Ultra-marathon running places significant stress on knee structures.
• Pre-existing knee conditions may be exacerbated by extreme endurance events.
• Magnetic resonance imaging (MRI) is a key tool for detecting soft tissue knee injuries.

Purpose of the Study:

• To detect and characterize knee injuries in non-professional runners using MRI after an ultra-marathon.
• To determine if ultra-marathon running exacerbates pre-existing injuries or causes new permanent damage.
• To assess the short-term and one-month post-race recovery of knee structures.

Main Methods:

• Prospective MRI study of 10 randomly selected runners completing the Comrades Marathon.
• Knee MRIs were performed 48 hours before, 48 hours after, and 1 month after the race.
• Scans were analyzed for joint fluid, tendon signal intensity, bone bruising, cartilage defects, and meniscal abnormalities.

Main Results:

• Increased joint fluid was observed in 5 runners immediately post-race.
• Increased signal intensity in patellar and quadriceps tendons was noted in 6 runners post-race, with improvement in 3 by 1 month.
• No bone bruising, cartilage defects, or meniscal abnormalities were detected. Old injuries remained unaffected.

Conclusions:

• Ultra-marathon running may negatively impact runners with pre-existing tendinopathy, as evidenced by MRI findings.
• Overuse injuries showed improvement or complete resolution by 1 month post-race.
• The study suggests ultra-marathons do not typically cause acute bone bruising or meniscal tears, with increased joint fluid likely due to stress.