PCL Injury
Lower LimbOverview
PCL injuries represent a significant knee ligament injury that occurs when the posterior cruciate ligament is stretched or torn, typically from direct anterior force to the proximal tibia or hyperextension mechanisms. These injuries are less common than ACL injuries but frequently occur in conjunction with other ligamentous injuries, potentially compromising knee stability and function. Early assessment and appropriate management are essential to prevent chronic instability and secondary degenerative changes.
Pathophysiology
The posterior cruciate ligament, originating from the medial femoral condyle and inserting on the posterior tibia, is the primary restraint to posterior tibial translation. When subjected to excessive force—particularly direct blow to the anterior proximal tibia, forced hyperextension, or combined rotational mechanisms—the ligament fibers undergo partial or complete disruption. This disruption impairs proprioceptive feedback and neuromuscular control, leading to altered knee biomechanics, increased tibiofemoral shear forces, and potential secondary damage to menisci, collateral ligaments, and articular cartilage. Grade I (partial tear) involves incomplete fiber disruption; Grade II represents significant partial tear with functional instability; Grade III indicates complete rupture with marked instability.
Patient Education
PCL injuries require early diagnosis and conservative management with graduated strengthening to restore dynamic stability; most isolated PCL injuries heal well without surgery if rehabilitation is consistent and activity is appropriately modified.
Typical Presentation
Site
Posterior and medial knee joint, with pain typically diffuse throughout the knee; posterolateral knee pain if posterolateral corner involved
Quality
Dull aching pain, sense of instability or 'giving way,' sensation of knee sliding backward
Intensity
Mild to moderate in isolated injuries (4-6/10); severe in acute complete tears or combined injuries (7-9/10); often less painful than ACL injuries acutely
Aggravating
Descending stairs, walking downhill, activities requiring deceleration, deep knee flexion, pivoting movements, sitting with knee flexed (posterior wall compression), prolonged standing or walking
Relieving
Rest and elevation, knee extension, ice application, anti-inflammatory medication, activity modification, knee bracing or taping
Associated
Posterior knee swelling (less obvious than ACL), sense of instability with cutting/pivoting, difficulty with running and jumping, pain with posterior tibial sag test, difficulty squatting, mild effusion, positive posterior drawer test, positive quadriceps active test
Orthopaedic Tests
Posterior Drawer Test
Procedure
Patient supine, hip bent to 45° and knee to 90°, foot flat. Sit gently on the foot, check the starting position of the tibia (look for a sag first), then push the upper tibia backwards and compare with the other knee.
Positive Finding
More backwards movement than on the other side, with a soft end-point.
Sensitivity / Specificity
Reference: Rubinstein RA et al., Am J Sports Med 1994; PMID 7943523
Interpretation
A positive test supports a posterior cruciate ligament injury. Check the starting position first: a tibia that already sags backwards can make the test look like an anterior drawer.
Quadriceps Active Drawer Test
Procedure
Patient supine, knee bent to 90°, foot held on the plinth. Ask the patient to gently try to slide the foot forwards (contract the quadriceps) while you watch the tibial tuberosity from the side.
Positive Finding
The tibia moves forwards as the quadriceps contract, out of its sagged position.
Related reference: Daniel DM et al., J Bone Joint Surg Am 1988; PMID 3346263
Interpretation
Shows that the tibia was sagging backwards at rest and supports a posterior cruciate ligament injury. Useful when the patient cannot relax enough for a passive drawer. Daniel (1988) found anterior translation in 41/42 PCL-deficient knees with no false positives (a small descriptive series); a formal sensitivity/specificity pair was not reported.
Posterior Sag Test (Gravity Drawer)
Procedure
Patient supine with both hips bent to 45° and knees to 90°, feet flat. Look at both knees from the side and compare the position of the tibial tuberosities.
Positive Finding
The tibia on the injured side sits further back (sags) than on the other side.
Related reference: Rubinstein RA et al., Am J Sports Med 1994; PMID 7943523
Interpretation
A visible sag supports a posterior cruciate ligament injury. Compare sides carefully; a small sag is easy to miss. The previously cited Lelli (2014) paper describes the "lever sign" for ACL, not the PCL posterior sag; no isolated sensitivity/specificity for the sag sign is established.
Dial Test
Procedure
Patient prone. Bend both knees to 30°, hold the feet and rotate both tibias outwards equally, and compare the angle between the foot and thigh on each side. Repeat at 90° of knee flexion.
Positive Finding
More external rotation on the injured side, usually by a clear margin.
Interpretation
More rotation at 30° only suggests a posterolateral corner injury; more rotation at both 30° and 90° suggests a combined posterolateral corner and posterior cruciate ligament injury. The external rotation recurvatum test is a separate test. The dial test assesses posterolateral corner rotational laxity rather than isolated PCL injury; the figure previously shown was not supported by the cited source.
Reverse Pivot Shift Test (Jakob Test)
Procedure
Patient supine and relaxed. Start with the knee bent to about 70–90°, the foot turned out and a valgus force applied. Slowly straighten the knee while keeping these forces.
Positive Finding
A clunk as the lateral tibial plateau moves forwards back into place, usually at about 20–30° of flexion.
Interpretation
Suggests posterolateral rotatory instability, often with a posterior cruciate ligament injury. Some people with lax knees have a positive test on both sides, so compare sides.
PCL Stress Radiograph (Posterior Drawer Stress View)
Procedure
Arranged by the specialist: a lateral X-ray of the knee at 90° of flexion while a standard backwards force is applied to the upper tibia, compared with the other knee.
Positive Finding
More backwards movement of the tibia on the injured side than on the other side.
Interpretation
Measures the amount of posterior laxity, which helps grade the injury and plan treatment. Interpreted by the specialist.
⚠ Red Flags
- •Acute severe trauma with inability to bear weight and significant swelling within 2 hours (suggests grade III tear or multi-ligament injury)
- •Vascular compromise signs: absent pedal pulses, pale or cyanotic foot, severe swelling with compartment pain
- •Signs of posterolateral corner injury with severe rotational instability
- •Associated fractures of tibial plateau, femoral condyle, or fibular head
- •Neurovascular deficit with peroneal nerve injury (foot drop, inability to dorsiflex)
- •Signs of complex knee dislocation with multiple ligament injuries
- •Uncontrolled swelling not responding to ice and compression within 48 hours
⚡ Yellow Flags
- •Catastrophic thinking about knee function and return to sport
- •Fear-avoidance beliefs regarding movement and activity, leading to deconditioning
- •Delayed presentation (>2 weeks) with ongoing instability and functional loss
- •High-level athlete with significant psychological distress regarding career implications
- •Poor compliance with rehabilitation expectations or denial of injury severity
- •Litigation or compensation issues related to injury circumstances
- •History of previous knee injuries with incomplete rehabilitation
- •Unrealistic expectations for rapid return to sport without appropriate progression
Osteopathic Techniques
Region
Quadriceps mechanism and vastus medialis obliquus
Technique
Rationale
Soft tissue mobilization to address quadriceps inhibition and restore dynamic stability; VMO activation is critical for dynamic posterior stability in isolated PCL injuries, reducing reliance on ligamentous restraint
Region
Hamstring and gastrocnemius muscles
Technique
Rationale
Muscle energy techniques to release hamstring and gastrocnemius tightness; these muscles normally provide dynamic posterior support to the tibia and posterior capsule; releasing tension facilitates optimal loading patterns and hamstring strengthening effectiveness
Region
Knee joint complex with emphasis on tibiofemoral joint
Technique
Rationale
Gentle articulation to maintain normal arthrokinematics and prevent capsular restriction; promotes synovial fluid nutrition to articular surfaces and maintains proprioceptive input through mechanoreceptor stimulation
Region
Posterior knee capsule, popliteal fossa, and posterolateral structures
Technique
Rationale
Deep soft tissue mobilization to address capsular inflammation and adhesion formation; improves circulation to healing tissues and reduces pain-mediated muscle guarding in posterior and posterolateral compartments
Region
Lumbar spine, hip flexors, and hip external rotators
Technique
Rationale
Addresses proximal kinetic chain dysfunction; hip weakness and lumbar stiffness cause compensatory knee stress; restoring hip mobility and pelvis control reduces excessive tibiofemoral shear forces during functional activities
Region
Ankle and foot complex
Technique
Rationale
Maintains distal kinetic chain mobility; ankle stiffness increases compensatory knee stress; optimizing ankle arthrokinematics distributes forces more efficiently through the lower limb during weight-bearing activities
Rehabilitation Exercises
Supine Knee Flexion and Extension
Prone Knee Flexion Slides
Supine Figure-Four Hamstring and Piriformis Stretch
Gastrocnemius and Soleus Wall Calf Stretch
Supine Quadriceps Setting with Towel Roll
Straight Leg Raise (Supine)
Seated Knee Extension with Resistance Band
Standing Hip Flexor Strengthening (Marching)
Standing Hip Abduction with Resistance Band
Prone Hamstring Curls with Resistance Band
Bilateral Stance Stability with Upper Body Movement
Single-Leg Stance with Hand Support
Double-Leg Stance on Foam Pad
Wall Squats (Partial to Full Depth Progression)
Step-Ups on 4-6 Inch Step (Bilateral)
Sit-to-Stand from Chair
Lateral Band Walk (Double Leg)
Clamshells (Hip External Rotation)
Quadruped Alternating Limb Extension
Single-Leg Stance on Unstable Surface
Single-Leg Squats (Assisted Progression)
Stationary Cycling (Upright, Moderate Resistance)
Referral Criteria
- •Multi-ligament knee injuries requiring surgical consultation (especially posterolateral corner injuries with rotational instability)
- •Acute grade III (complete) PCL tear in young athletic population considering surgical reconstruction
- •Associated fractures (tibial plateau, femoral condyle, fibular head) requiring orthopedic specialist evaluation
- •Vascular or neurological compromise requiring emergency vascular surgery consultation
- •Unresolved swelling and effusion persisting beyond 4 weeks despite conservative management
- •Persistent severe instability not improving with 6-8 weeks of appropriate rehabilitation
- •Significant secondary meniscal or cartilage damage identified on imaging
- •Failure to progress in rehabilitation or developing chronic pain syndrome features
- •Athlete seeking clearance for high-impact sport return requiring sports medicine evaluation
- •Suspected complex knee dislocation or posterolateral corner involvement requiring specialized imaging and assessment
- •Development of persistent swelling with compartment syndrome concern
- •Patient preference for surgical intervention after failure of conservative management trial