Non-operative Treatment of PCL Injury

Original Editor - Mariam Hashem

Top Contributors - Mariam Hashem, Kim Jackson, Tony Lowe, Tarina van der Stockt and Jess Bell

Basic Structure and Function

The PCL is a very large ligament, located posterior to the ACL, comprised of 2 bundles:

1. Anterio-medial: taught when knee is in flexion
2. Posterio-medial bundle: taught when knee is in extension

Both bundles work synergistically to create stability within the knee.

Functions:

• PCL is the primary restraint to posterior translation of tibia relative to femur
• Secondary stabilizer resisting tibial external rotation as well as valgus/varus stresses

It often occurs in combination with other ligamentous damages.

The mechanism of injury involves some type of varus or valgus force in combination with posterior tibial force.

Decision making and physical Examination

Positive posterior drawer and posterior tibial sag signs are the most important tests to diagnose PCL and identify the management plan.

The decision regarding conservative or surgical management depens on the grade of injury and the associated soft tissue damage.

Grades:

• Grade I: 0-5 mm posterior tibial translation
• Grade II: 5-10 mm posterior translation
• Grade III: > 10 mm posterior translation

Surgery is indicated for:

• All grade III comined PCL and posterior lateral corner injuries. The combination of posterior laxity and rotational instabilty may lead to suboptimal outcomes as the joint fail to regain stability essential for an active work life or return to sport when returning to sports.
• Grade II and III isolated PCL failed conservative treatment reporting repeated instability and/or tibial shifitng with activities
• Multi-ligamentous injury

.Isolated PCL injuries, regardless of the grade, can be considerd for conservative treatment.

Conservative Management Outcomes

When considering Non-operateive management for PCL, it's important to discuss short and long term goals with the patient for optimal decision making.

One study looked at 46 patients with MRI confirmed grade II and III PCL injuries managed conservatively from the time of injury until they returned to sports and reviewd them again at 5 years after the injury. The study reported an average of 16 weeks from the time of the injury until return to competitive sports. 91% of thoses who returned to sports were able to play at the same level or higher at 2 years, and 69% played at the same level at the five year follow up. This indicates good outcomes of non-operative manegment in terms of returning to high levels of play and function.

Despite the successful return to sports, the developmenet of osteoarthritis is evident following Non-operative PCL management.

A study that investigted 14 patients with PCL injuries found increased anterior medial location of peak cartilage deformation reflecting higher than normal loads placed on the medial knee compartment. Another study in 2003 of 181 patients with PCL injuries treated conservatively after five years following injury, reported 77% degenerative changes in the medial femoral condyle and 47% had degenerative changes in the trochlea.

Rehabilitation

The principals are no differnet from those following operative management.

Basicly, to allow the ligamen to heel in a neutral position, there are few essential precautions/restricitons :

1. Limiting gravity force that creates more posterior tibial sagging by encouraging your pateint in the first 6 weeks to avoid positions where there is a tibia sag such as wall slides. You can also advice sleeping with a pillow underneeth proximal tibia putting tibia in a better position and reducing the posterior drawing force.
2. Dynamic PCL brace is considered one of the huge advances in PCL management. It works as a spring applying constant force drawing the tibia anteriorly and reducing tibial sag. Ideally PCL brace should be worn for 24 hours (only to when taking a shower) for 16 weeks. A study in 2010 alayzed the effect of PCL dynamic brace on 21 patients for one year found a reduction by 2.3 of posterior tibial drawing at 12 months. This reflects the intrinsic heeling capacity of PCL and the effect of the PCL brace on reducing the grade of the injury. If the patient is unable to afford the cost of the brace, a knee mobilizer for the acute phases can be an alternative then advice switching to a hinge athletic brace with PCL strap for 12 months or longer depending on the knee stability.
3. When working on improving the ROM, advice exercises from prone position to limit the effect of gravity.
4. Limit WB initially to restore joint homeostasis if the injury is accompained by effusion and joint bleeding.
5. Limit isolated hamstrings contraction at greater than 15 degrees knee flexion for at keast 16 weeks as it was found to increase the load on PCL (2004 study). Instead, you can advice an exercise such as Romanian deadlift where there is a small knee flexion to avoid excessive tibial forces.