Basic Structure and Function
The PCL is a very large ligament on the outside of the ACL that consists of two ligaments:
- Anterolateral: tightness in knee flexion
- posteromedial bundle: tight when the knee is extended
The two bundles work together to create stability within the knee.
- The PCL is the primary constraint on posterior translation of the tibia relative to the femur 
- Secondary stabilizer against tibial external rotation and valgus/varus stresses 
PCL is rarely injured alone.  They often occur in conjunction with other ligamentous meniscus or cartilage injuries.  They are far less common than ACL or other knee ligament injuries. 
The injury mechanism involves some type of varus or valgus force combined with tibial posterior force.
Decision Making and Physical Examination
Posterior drawer sign and posterior tibial ptosis are the most important tests for diagnosing PCL and determining treatment options.  Posterior tibial ptosis is considered the most sensitive test of PCL integrity. 
The decision regarding conservative or surgical management depends on the extent of the injury and associated soft tissue damage.
- Grade I: 0-5mm tibial posterior displacement
- Grade II: 5-10 mm posterior translation
- Grade III: > 10 mm posterior translation
Surgery is indicated for:
- All grade III combined PCL and posterolateral corner injuries. The combination of posterior laxity and rotational instability can lead to suboptimal results, as the joint is unable to regain the stability necessary for an active working life, or is unable to return to motion when returning to motion.
- Grade II and III isolated PCL failure of conservative treatment reported recurrent instability and/or tibial displacement with movement
- Multi-ligamentous injury
Conservative management can be considered for isolated PCL injuries, regardless of grade.
Conservative Management Outcomes
When considering nonsurgical treatment of PCL, it is important to discuss short-term and long-term goals with the patient for the best decision.
A study of 46 patients with MRI-confirmed grade II and III PCL injuries who were treated conservatively from the date of injury until their return to sport was reviewed 5 years after the injury . It takes an average of 16 weeks from injury to recovery, the study reported competitive sports. Ninety-one percent of those who returned to sport were at the same level or better at 2 years, and 69% were at the same level at 5 years of follow-up. This demonstrates the favorable outcome of non-surgical management in restoring high levels of play and function. 
Despite a successful return to sport, the development of osteoarthritis was evident after nonsurgical PCL management.
A study of 14 patients with PCL injuries found an increased anteromedial location of peak cartilage deformation, reflecting higher than normal loading on the medial knee compartment. Another 2003 study followed 181 patients with PCL injuries who were treated conservatively for five years Degenerative changes were reported in 77% of the medial femoral condyle and 47% of the trochlear after injury .
The principles of rehabilitation are no different from those after surgical treatment.
Basically, few precautions/restrictions are necessary in order for the ligament to heal in a neutral position :
- Limit gravity to cause posterior tibial prolapse by encouraging your patient to avoid tibial prolapse positions such as sliding walls for the first 6 weeks. You may also suggest sleeping with a pillow under the proximal shin to keep the shin in better condition position and reduce rear tension.
- The dynamic PCL stent is considered one of the great advances in PCL management. It acts like a spring, applying a constant force to pull the tibia forward and reduce tibial sagging. Ideally, a PCL brace should be worn 24 hours a day (except in the shower) for 16 weeks. A 2010 study  analyzed A one-year study of the PCL dynamic brace in 21 patients found a 2.3mm reduction in posterior tibial tension at 12 months. This reflects the intrinsic healing capacity of the PCL and the effect of PCL bracing on reducing the extent of injury. If the patient cannot afford the cost An acute knee immobilizer with a brace can be used as an alternative. Then use a hinged sports brace with PCL straps for 12 months or more depending on the stability of the knee.
- When improving ROM, start in the prone position to limit the effects of gravity.
- If injury is accompanied by effusion and joint bleeding, limit WB initially to restore joint homeostasis.
- Limit isolated hamstring contraction for at least 16 weeks when knee flexion exceeds 15 degrees, as it has been found to increase PCL loading . Instead, you could suggest exercises such as the Romanian deadlift, where the knees are slightly bent to avoid overstressing the shins.
- Restore ROM
- Reduce swelling
- Manage the inflammatory process
- Restore muscle function
ROM: (0-4 weeks)
1- Assisted prone ROM exercises
2- Progress to stationary bike when 115 degrees of knee flexion is achieved or when ROM allows rotation on bike.
- Load management by limiting weight bearing to allow healing.
Muscle Function: Teaching the quadriceps to activate is critical because the quadriceps pull the tibia forward to improve stability. Encourage contraction of the isolated quadriceps by pulling upward on the patella.
Weight-bearing exercise can be performed when the patient meets the following conditions:
- 130 degrees knee flexion
- Terminally knee extension
- Ability to walk comfortably for a distance in a brace
- Muscular Endurance (Weeks 5-10): Low loads and high reps. For example; 3-4 sets of 15 repetitions, resting for 40 seconds. Exercise example:
- Forward and backward with Theraband
- Bilateral squat
- Do oddball exercises, such as walking down a 1-inch box
- Single leg Romanian deadlift or deadlift
- Muscle strength (11-16 weeks): low frequency and high load. s.e., s.e. 10-12 repetitions 3 sets with 1 minute rest. You can modify the same exercises used for endurance training and adjust the parameters or advise higher load exercises such as the elevated splint squat. Again Lumbo-pelvic rhythm too exercise is important for stability
- Strength agility and running (weeks 17-20/22)
Return to Sports
It is recommended that a proper strength program be completed prior to returning to sport.
Criteria for promotion or return to competition:
There are criteria available in the evidence, but the symmetry of the following measures reflects strength and stability :
- Quadriceps strength
- Y balance anterior reach distance
- Power test such as hop test
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- Posterior Drawer test for PCL. Available from:https://www.youtube.com/watch?v=HTti7-c1MFk
- Posterior Sag Test. Available from: https://www.youtube.com/watch?v=kB__q4Y4lfA
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- medi GmbH & Co. KG. M.4s® PCL dynamic – The new standard for PCL therapy. Available from: https://www.youtube.com/watch?v=BuQyPI0-b9U
- Y Balance Test Explained . Available from:https://www.youtube.com/watch?v=1gfGkxWlx4o
- Exercises: Single Leg Hop Test . Available from: https://www.youtube.com/watch?v=iNzGCet0Ll0