Bayern Munich forward and French international Kingsley Coman injured his left knee on 12/11 in the 27th minute of Bayern’s Champions League group stage match against Tottenham. The injury was diagnosed as left knee capsular tear, biceps femoris strain, and “jarring of the knee joint”.
In this piece, I’ll explain Coman’s injury, why he’s fortunate to have avoided serious injury, and when he’ll be back on the pitch. If you’re more of a visual learner, then click the video below.
Mechanism of injury
After racing to the touchline to save a ball, Coman awkwardly planted his left leg resulting in severe hyper-extension of the knee, the joint getting pushed posteriorly (backwards) outside its normal range of motion.
Biceps femoris tear (strain)
Said hyper-extension placed a huge stretch on Koman’s hamstrings and one of them – the biceps femoris muscle – was overstretched and suffered an acute tear (aka a strain, don’t let the word “tear” scare you).
This muscle actually consists of two heads – long and short – and is the most commonly injured hamstring muscle, specifically the short head. For example, Barcelona’s Jordi Alba has been limited with a biceps femoris tear and re-aggravation nearly all season.
The knee hyper-extension also places a huge stress on the tibiofemoral articular joint capsule aka the knee capsule. This wide and lax capsule surrounds the knee joint and thins anteriorly (in front) and on the sides. It contains the patella (knee cap), menisci, ligaments, and bursae.
Further, the knee capsule consists of two layers – an outer fibrous membrane and inner synovial membrane. The latter helps provide nutrients to the synovium – fluid that lubricates the joint – and avascular cartilage (cartilage without a blood supply).
“Jarring of the knee joint”
Lastly, the sudden hyper-extension can create instability in the knee joint and trauma to the knee cartilage. This is quite common with high force acute knee injuries.
Coman’s good fortune
Coman was very fortunate because severe knee hyper-extension commonly also results in ruptures of the posterior cruciate ligament (PCL) and/or anterior cruciate ligament (ACL).
To that point, the team initially feared Kingsley had ruptured a cruciate ligament but thankfully those fears weren’t confirmed during examination or imaging.
Coman’s return to play timeline
A capsular tear injury without moderate or severe ligament damage is a relatively unique injury so there isn’t much data or precedent out there when it comes to return to play (RTP) protocols or timeline.
That being said, Bayern Munich issued a statement that they expect Coman to be back in January and that timeline lines up with the limited data I could find.
Kingsley will very likely be placed into a splint for upwards of three weeks to allow the capsule to heal and then methodically progress through rehab and back to the pitch.
Risks moving forward
Moving forward, I’m far less concerned about the joint capsule than I am potential re-injury to the biceps femoris muscle.
That’s because hamstring strains are notoriously sensitive – ask Dembele – with high quality research showing that there’s increased re-injury risk for upwards of a year with nearly 30% of professional footballers re-aggravating the hamstring, most within the first two weeks.
Accordingly, the medical staff will keep a close eye on Kingsley as he makes his return but hey, I’m sure they far prefer that option to the alternative of a cruciate ligament rupture, surgery, potentially 7-9 months out, and a plethora of downstream risks.
That’s a wrap for this piece. Thanks for reading. My goal is to provide you with in-depth, evidence based, narrative free analysis and you can always find me on Instagram and Twitter @3CBPerformance. Make sure to subscribe to the blog below and the YouTube channel for the latest updates. 3CB out.