The Posterior cruciate ligament (PCL)
lies just behind the ACL
and similarly connects femur and tibia but runs in a different direction. The PCL
is the primary stabilizer of the knee and the main controller of how far backward tibia moves under femur. This motion is called posterior translation of tibia. If tibia moves too far back, the PCL
Recent studies have suggested that the PCL
also prevents medial-lateral (side-to-side) and rotatory movements. Thus the PCL's
effect on knee joint function is more complex than previously thought.
is made of two thick bands of tissue bundled together. One part of the ligament tightens when the knee is bent; the other part tightens as the knee straightens. This is why the PCL
is sometimes injured along with the ACL
when the knee is forced to straighten too far, or hyperextend.
Both bundles of the PCL
change in length as well as orientation (direction of the fibers) from front-to-back and side-to-side with knee flexion and extension. This function allows the ligament to keep tibia from sliding too far back or slipping from side-to-side.
» Tear of the Posterior Cruciate Ligament :
injuries can occur with low-energy as well as high-energy trauma. Isolated PCL
tears occur in sports, but they are less frequent and less disabling than ACL
tears are often missed or misdiagnosed, and therefore probably more common than believed.
The most common way for the PCL
alone to be injured is from a direct blow to the front of the knee while the knee is bent. Since the PCL
controls tibia’s movement in backward direction in relation to femur, if tibia moves too far, the PCL
can rupture. Sometimes the PCL
is injured during an automobile accident. This can happen if a person slides forward during a sudden stop or impact and the knee hits the dashboard just below the kneecap. In this situation, tibia is forced backward under femur, injuring the PCL
. This injury is termed as a dashboard injury
. The same problem can happen if a person falls on a bent knee. Again, tibia may be forced backward, stressing and possibly tearing the PCL
tears are interstitial and heal with time, developing a firm endpoint although in a lax position. Most people are able to return to full activities with nonsurgical therapy. However, chronic PCL
laxity causes significant patello-femoral problems (anterior knee pain), because of the chronic posterior translation of tibia and increased pressure on patellofemoral articular cartilage. Long-term follow-up after nonsurgical management has revealed that most patients rate the knee as good enough and are able to return to sports.
Other parts of the knee may be injured when the knee is violently hyperextended, but other ligaments are usually injured or torn before the PCL
. This type of injury can happen when the knee is struck from the front when the foot is planted on the ground.
» Symptoms :
Pain at the time of impact which over time may also be felt in the calf region.
Swelling, although this may be minimal.
Instability of the joint, perhaps associated with the feeling of the knee giving way.
» Signs :
Posterior Sag Test :
Posterior Sag Test
Posterior Drawer Test
Reverse Lachman Test
The posterior sag test is performed by raising the lower leg to a horizontal position, with the knee bend. The therapist observes if tibia drops down, forming a sag or dent at the front of the upper shin. Always compare to the other knee.
Over straightening or hyperextending the knee may be painful in PCL injuries.
Posterior drawer test :
The posterior drawer test involves pushing tibia (shin bone) backwards whilst the knee is bent. A positive result is recorded if tibia moves back further than on the uninjured side.
» Diagnosis Confirmation :
Conservative treatment for isolated PCL tears :
Phase 1 : Immediately following injury till 2 weeks :
Goal - To control swelling, maintain the ability to straighten and bend the leg and to begin strengthening exercises for the leg muscles when possible.
Phase 2 : 2 weeks to 4 weeks :
- Rest from aggravating activities. Use crutches if necessary. Complete rest for the first 48 hours, after then let pain be the guide to the speed of progression of rehabilitation.
- Apply cold therapy and compression as soon as possible following injury and for 15 minutes every 2 hours for the next 24 to 48 hours. The frequency of application can be gradually reduced over the next few days to no less than 3 times a day and always after mobility or strengthening exercises.
- Stretching exercises for the lower leg and upper body. Calf stretches, hamstring stretch, ankle mobility, pain free knee mobility exercises. If it hurts, do not pursue it
- Strengthening exercises (pain free) - static quads, static hamstring holds, calf raises (both legs).
- By the end of week 2, the athlete should aim to be walking normally without aids.
Goal - To completely eliminate swelling, regain full mobility and build on strengthening exercises. By the end of this phase the athlete may be able to do 'proper' cycling or light swimming.
Phase 4 : 6 weeks to 8 weeks :
- Apply cold therapy and compression 3 times a day until swelling is eliminated. Once this is achieved, apply cold fomentation after every training session.
- Mobility exercises - continue to work on these, if full mobility has not been achieved. Otherwise progress onto more usual stretching exercises as long as they do not cause pain in the knee.
- Strengthening exercises - continue with phase 1 exercises and also begin to include standing static quads (instead of sitting), half squats (both legs), hip raises, hip exercises against resistance, step ups and single leg calf raises.
Goal - To return to sports specific training and competition.
- Cold therapy and compression bandage should not be required during this stage. If there is still swelling on the knee it may be necessary to go back a stage or two.
- Full sports specific flexibility training should be done through regular stretching before and after training sessions, on a daily basis.
- Sports massage techniques to the surrounding muscles will help recovery after training and keep muscles in better condition.
- Sprinting speed should now be near to normal and the athlete should be able to change direction at speed and perform other sports specific tasks without pain or unease. Normal sports specific training should now be resumed.
- When the athlete is confident he/she should return to the sport in a limited capacity for example a footballer may play only 20 minutes of a game. This will gradually introduce them to the demands of competition both physically and psychologically.
PCL Reconstruction :
» Do I Need Surgery?
In general, most partial or isolated PCL
tears can be treated non-operatively because the PCL
, with its synovial covering, has some ability to heal.
However, surgical reconstruction is usually recommended for PCL
tears that occur in combination with other ligament tears of the knee.
It is usually recommended that acute PCL
tears in combination with and ACL
, Posterolateral Corner
, or MCL
tears should be reconstructed within the first three weeks of injury. In rare occasions, the PCL
may be repaired when it occurs as a peel off or bone avulsion injury. In patients with chronic PCL
isolated injuries, who are symptomatic for pain and instability, reconstruction may be indicated. It is important that in these chronic injuries that a workup for possible concurrent other ligament injuries, as well as an assessment of the extremity alignment, should be performed.
PCL reconstruction is typically done as an outpatient procedure. Depending on graft choice, open incisions may be necessary to harvest the tissue that is to be used as the new PCL. Knee arthroscopy is then performed to inspect the knee, treat additional injuries (meniscus tears or cartilage damage), and to prepare the knee for the new PCL.
Once the graft tissue has been prepared and the torn PCL tissue has been removed, the surgeon is ready to place the ligament within the knee. Small tunnels (7-10 mm) are drilled in tibia and femur to allow the ligament to be pulled up into the knee.
Accurate placement of these tunnels is critical to success of the PCL surgery. After the PCL graft is in position, fixation devices (screws, washers, buttons, etc.) are used to keep it there until it can heal the place.
» Surgical steps
- The surgeon inspects the knee and may or may not remove the remains of the old PCL.
- The graft which is used for reconstruction is harvested and prepared for the replacement. Usually the patellar tendon or the Semitendinosis and Gracilis tendon
autografts are used in athletes.
- After harvesting the tissue, a hole is drilled from the front of tibia diagonally into the knee and ends up where the PCL attaches to the top of the shin. Next, the surgeon drills
a hole in femur between the two heads running diagonally and up from the middle to the outside. The PCL surgery differs from the ACL in that additional posteromedial
Portal is made in PCL surgery to view the back of the knee from where the PCL comes out from tibia.
- The harvested replacement graft is pulled into place through the holes which were just drilled.
- The new ligament is then held into place by two bioabsorbable screws or metallic screws.
» Rehabilitation After Reconstructive Surgery
Postoperative Rehabilitation Protocol for
PCL / ACL Reconstruction
Posterolateral Corner Surgery
» General Guidelines
> Program is designed to protect the PCL.
> Even if there is a co-existing ACL injury the program remains the same.
> No active hamstring work.
> Caution against posterior tibial translation (gravity, muscle action).
> PCL with posterolateral corner or LCL repair follows different post-operation care, i.e. use of crutches 8 weeks and brace to avoid varus stress.
Schedule for physiotherapy :
Formal visits by a physiotherapist begins after removal of sutures, about 2 weeks.
This supervised therapy continues initially every alternate day and later about twice a week for about 3 months.
Patient has to continue home exercises, as instructed by the physiotherapist on a daily basis.
» General progression of activities of daily living
Patient may start with the following activities of daily living as follows:
> Showering - once dressing removed.
> Sleep without brace - 8 weeks post-operation.
> Driving - when safely able to operate the controls of the vehicle.
> Full weight bearing without assistive devices - 6 weeks for just PCL, but need 8 weeks when any lateral side surgery also performed.
» Schedule of physiotherapy
> Formal Visit by a physiotherapist begins one month after surgery.
> This supervised therapy continues initially every alternate day and later about twice a week for about 3 months.
Patient has to continue the home exercises as instructed by the physiotherapist on a daily basis.
» Phase I
This is the phase immediately after surgery till about 4 weeks. In this phase the patient performs hip, knee and ankle strengthening exercises.
The goal of rehabilitation in phase 1 is to protect the healing of soft tissue and bones, as wells as to mobilize the knee to prevent stiffness of the joint.
> Full weight bearing with the help of walking aid is initiated in this phase.
> Toe touch weight bearing is initiated in this stage with the help of crutches or walker.
> For the first 2 weeks, the patients needs to wear the long knee brace at all times, but from 2 weeks to 4 weeks the brace is unlocked for passive range of motion to
> A pillow is kept under proximal tibia, when the patient is lying down, to prevent posterior sag.
Therapeutic Exercises :
> Hip flexion, extension, abduction and adduction if able
> Straight leg raises for quads
> Ankle pumps
> Calf press with theraband
All the above as well as the following :
The brace is unlocked for passive range of motion to 60 degrees with patients.
instructed for passive flexion and active knee extension to prevent posterior tibial translation.
» Phase II
Begins at 1 month after surgery, and continues till 3 months after surgery.
> Increase range of motion
> Progress in weight bearing
> Continue lower extremity muscle toning (except active hamstring work)
> Continue to protect graft(s). In cases of isolated PCL or ACL + PCL injuries, the brace is removed at 6 weeks. In cases where there is an associated postero-lateral corner.
Therapeutic Exercises :
> 4-6 weeks :
When patient exhibits independent quad control, one may begin open chain extension.
Begin isometric quads and co-contraction of quadriceps/hamstrings in extension
Only progress to active knee extension as tolerated from point of maximal flexion (passively) to full extension.
> Progress to mini-squats when able to full weight bearing.
> May begin or continue hip flexion / extension / abduction / adduction with knee fully extended.
> Underwater exercises or walking is encouraged during this phase (normal heel-toe gait pattern in chest deep water).
6-12 weeks : Once patient is full weight bearing and does not require the brace, therapy can be liberalized and proceeded with on a more “as tolerated” basis.
> Stairmaster and/or elliptical machines can be used for cardio and leg conditioning.
> Balance and Proprioception activities (e.g. single leg stance).
> Open chain hamstring activity is avoided during this phase to prevent posterior tibial translation.
» Phase III
Begins approximately three months after surgery, and continues till about nine months after surgery.
> Restore any residual loss of motion that may prevent functional progression.
> Improve functional strength and proprioception utilizing closed and/or open kinetic chain exercises. Continue to work on restoration of functional progression of the extremity and the patient as a whole in preparation for return to specific activity or sport.
Therapeutic Exercises :
> Continue lower extremity exercise progression.
> Treadmill walking progress to running as tolerated.
> Stairmaster / elliptical trainer, swimming is allowed.
> May progress to out door biking, walking and ultimately running.
> May play golf or bowling if able.
> No twisting turning or jumping activities yet.
» Phase IV
Return to sport at approximately 6 months to 9 months.
> Safe and gradual return to work or athletic participation
> This may involve sports specific training
> Maintenance of strength, endurance and function
> Running progression
> Jumping (plyometrics) if needed for sport (i.e., volleyball or basketball)