Officially Juventus says this:
During the game last night,
Merih Demiral sustained a sprain to his left knee.
The diagnostic tests carried out at J | Medical this morning revealed injury to the
anterior cruciate ligament along with
associated injury to the meniscus.
Surgical intervention will be required in the coming days.
And from a medical website:
Description
About half of all injuries to the anterior cruciate ligament occur along with damage to other structures in the knee, such as articular cartilage, meniscus, or other ligaments.
Injured ligaments are considered "sprains" and are graded on a severity scale.
Grade 1 Sprains. The ligament is mildly damaged in a Grade 1 Sprain. It has been slightly stretched, but is still able to help keep the knee joint stable.
Grade 2 Sprains. A Grade 2 Sprain stretches the ligament to the point where it becomes loose. This is often referred to as a partial tear of the ligament.
Grade 3 Sprains. This type of sprain is most commonly referred to as a complete tear of the ligament. The ligament has been split into two pieces, and the knee joint is unstable.
Partial tears of the anterior cruciate ligament are rare; most ACL injuries are complete or near complete tears.
Surgical Treatment
Rebuilding the ligament. Most ACL tears cannot be sutured (stitched) back together. To surgically repair the ACL and restore knee stability, the ligament must be reconstructed. Your doctor will replace your torn ligament with a tissue graft. This graft acts as a scaffolding for a new ligament to grow on.
Grafts can be obtained from several sources. Often they are taken from the patellar tendon, which runs between the kneecap and the shinbone. Hamstring tendons at the back of the thigh are a common source of grafts. Sometimes a quadriceps tendon, which runs from the kneecap into the thigh, is used. Finally, cadaver graft (allograft) can be used.
There are advantages and disadvantages to all graft sources. You should discuss graft choices with your own orthopaedic surgeon to help determine which is best for you.
Because the regrowth takes time, it may be six months or more before an athlete can return to sports after surgery.
Procedure. Surgery to rebuild an anterior cruciate ligament is done with an arthroscope using small incisions. Arthroscopic surgery is less invasive. The benefits of less invasive techniques include less pain from surgery, less time spent in the hospital, and quicker recovery times.
https://orthoinfo.aaos.org/en/treatment/acl-injury-does-it-require-surgery/
Can you walk on it?
https://www.aclinjuryrecovery.com/can-walk-completely-torn-acl/
Walking with a completely torn ACL is certainly realistic for most people
- Walking with a completely torn ACL is almost always achievable for most people
- For most people, the most likely time that walking is impacted is within the first few days after an ACL tear due to the onset of pain and swelling upon injury
- If you have torn your ACL you should still have strong enough functionally in your knee that enables you to walk
- Rupturing the ACL will lead to instability in the knee. The feeling of the knee giving way is most often felt with certain movements that involve sudden changes of direction.
- When giving way or buckling of the knee occurs this increases the risk of further injury such as damage to the cartilage
- In most cases movements in straight lines including walking and running are achievable and should not cause further damage
- These activities can often be performed with relative ease even if you have completely torn your ACL
- The extent to which walking is impacted by an ACL rupture is often linked to the level of pain and swelling in the knee. This is most often felt in the first few days after injury
- In this respect if you have just hurt your knee on the sports field or somehow else and you are showing symptoms of an ACL injury – it is also possible that other areas of your knee have also been injured such as the surrounding cartilage and other ligaments
- Any other damage to your knee in addition to tearing of the ACL is likely to contribute in vary degrees to pain and swelling in your knee
- Therefore it is the combination of a torn ACL and any other damage to your bad knee which can impact your ability to walk