80 minutes into the North London Derby, Arsenal hold a comfortable 2-0 lead and Theo chases back to nick the ball off Danny Rose. He stretches his left leg in front of the hapless spud to win the ball but immediately crumples to the ground in pain.
He lies there immobile while Bacary Sagna signals to the medical team. As a physio these are always the injuries that worry you most at pitch side. In most cases if a player is comfortable enough to roll around on the floor they often haven’t done much lasting damage. If however they won’t move at all alarm bells start ringing.
Despite Theo putting a brave face on things the Arsenal medical team were clearly worried and arranged a scan for Monday morning which confirmed one of the worst injuries in football – an anterior cruciate ligament (ACL) tear.
The ACL is a ligament deep within the centre of the knee. It helps prevent excess movement between the tibia and femur. It’s vulnerable to injury when there is a twisting force on the knee. Classically the upper leg moves inward with the lower leg fixed in place with the foot on the ground. Reviewing Theo’s injury in slow mo it appears this happens as he reaches for the ball – video here.
Note in the second picture that Theo’s foot remains pointed towards the ball while his upper leg rapidly changes direction. It’s always hard to be 100% sure of the exact mechanism of an injury but this appears most likely. It’s possible the injury occurs milliseconds later than this as the knee flexes more and there is further movement of the upper leg. However at that stage Theo’s heel has lifted from the floor allowing more movement of the lower leg to compensate.
Unlike other structures in the body the ACL won’t simply heal on its own. The broken parts of the ligament are no longer in contact with each other. Away from elite sports around 50% of people who suffer an ACL tear will have surgery and many can recover well with adequate rehab. However in elite sports the vast majority will opt to reconstruct the ligament and allow full return to sport.
The surgery involves replacing the ligament, usually with a section taken from the patient’s hamstring or patella tendon. This is screwed in place within the knee. During rehab this graft needs to be protected and as a result there is a fairly restrictive protocol for rehab which will differ depending on the surgeon. Rehab after surgery is often done in stages based on time (to allow graft healing) and improvement in range of movement, muscle strength and function.
For the first 1-2 weeks weight-bearing may be restricted and sometimes a brace is used. Those with a good memory mighty recall footage of Robert Pires on crutches, hobbling around in a brace after his ACL surgery. From around 2 weeks onward patients are usually weaned off braces and crutches. Rehab starts at day 1, with very gentle exercises to maintain muscle function and reduce swelling.
These are gradually progressed at each stage with the aim being to restore full range of movement in the knee and strengthen all the muscles which support and stabilise the joint. Typically rehab will focus on quads, hamstring, glutes and calf muscles and will include balance and control work as well resistance training. At approximately 3 months post op, when the graft has had adequate time to heal, rehab is usually progressed to include impact, progressive strength work, plyometrics and sport specific rehab.
Return to sport usually takes 6-9 months post op and prognosis is based on a host of factors. ACL injuries often result in damage to other structures in the knee such as the meniscus or medial collateral ligament which can affect outcome. Player’s response to rehab varies a great deal and secondary injuries or relapses can be an issue. In addition the psychological impact of long term injury shouldn’t be underestimated and fear of re-injury can be a barrier in return to sport.
The best case scenario for Theo would be a return to full training in the summer, potentially in mid-July. I suspect he’ll have limited involvement in pre-season but may start to feature in the squad in the early stages of next season.
On a personal level for Theo this must be a huge blow. In recent seasons he’s developed into a real danger man for Arsenal. Although his performances this season have been restricted by injury he’s had an big impact since his return and this season we’ve won 78% of the games he’s featured in compared to just 54% of the games he hasn’t (source Sky Sports News). To be developing well as a player in a team top of the league and then face 6 months out must be devastating.
We wish him a speedy and successful recovery, his first aim of rehab should be to be strong enough in May to help us lift a few trophies!