Introduction
- Robert F. LaPrade, MD, PhD
- Casey M. Pierce, MD
- Scott A. Wilkins, DPT, OCS
- Casey M. Pierce, MD
Epidemiology
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Injuries to the posterior cruciate ligament (PCL) are rare compared with ACL injuries.
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Comprise between 3% and 23% of knee injuries and usually occur in combination with other ligament injuries
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Schulz et al. reported that 33% of PCL injuries are sports related.
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These numbers are highly dependent on the patient population because PCL injuries are most frequently trauma associated rather than sports related.
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The PCL has an intrinsic healing capacity not seen in the ACL, so chronic injuries can undergo some healing and can go undiagnosed for long periods of time.
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Low grade/minor tears can be asymptomatic.
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NFL football player study found 2% of pre-draft players have PCL insufficiency.
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Isolated PCL injuries are less common and account for between 3% and 20% of PCL injuries.
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PCL is stronger than the ACL in terms of tensile strength.
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Age
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Mean age 27.5 ± 9.9 years
Sex
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Almost 80% male likely because of a higher number of males active in contact/collision sports
Sport
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Contact/collision sports, skiing, and soccer mostly but also football, hockey, and wrestling
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40% sports related
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Position
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Soccer goalie, also players in football who get tackled (quarterback, running back, wide receiver)
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Mechanism of injury puts them at risk for the common flexed knee with anterior tibial blow mechanism
Pathophysiology
Intrinsic Factors
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Movement patterns that are common are falls on a flexed knee, which are commonly seen with cutting in football and planting for leverage in wrestling.
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Neuromuscular development, proper training, stretching, strengthening, and conditioning and proper technique when landing from a jump can contribute to preventing PCL injury.
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There is an increased risk seen with affected siblings, so there is a probable genetic component.
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Decreased risk with certain genetic mutations and polymorphisms in the COLIA1 gene
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Specifically increased production of collagen type Iα 1 mRNA and proteins
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Increases tensile strength of tendons
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Also characteristic of fibrotic diseases and low bone mineral density (BMD)
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Increased risk with other polymorphisms of the COL1A1 that lead to increased risk of soft tissue rupture
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Age, flexibility, previous injury, overuse
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Unlike the ACL, the PCL has an intrinsic ability to heal and is stronger so it is less likely to be injured
Extrinsic Factors
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Footwear: With any sport footwear, it is critical to help prevent slipping and twisting injuries to the knees.
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Environmental conditions that increase the likelihood of slipping or hyperextending the knee increase the risk of injury:
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Wet or icy fields could contribute to this.
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Lifestyle
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Motor vehicle accidents are a common cause with the well-known “dashboard” injury (knee driven into dashboard on impact)
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Rigid structures on the playing field such as soccer, football, or hockey goal posts
Traumatic Factors
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Typical mechanism is a direct anterior proximal tibial blow to a flexed knee like a hockey goalie sliding into the goal post or soccer goalie sliding into another player ( Figure 33-1 A )
FIGURE 33-1
The three most common mechanisms of injury to the posterior cruciate ligament: direct anterior proximal tibial blow to a flexed knee ( A ), falling on a flexed knee with the foot plantarflexed ( B ), and sudden, powerful forced hyperextension ( C ).
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Second most common is fall on the flexed knee with foot plantarflexed illustration ( Figure 33-1 B )
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Third most common is sudden, powerful forced hyperextension ( Figure 33-1 C )
Classic Pathological Findings
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Increased posterior translation on posterior stress x-rays ( Figure 33-2 )
FIGURE 33-2
Posterior stress radiographs: setup ( A ) and an example radiograph ( B ).
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Increased posterior sag of the tibia
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Midsubstance ruptures
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Proximal or distal bony avulsions ( Figure 33-3 )
FIGURE 33-3
Sagittal magnetic resonance image of a PCL tibial avulsion.
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On arthroscopy, the torn PCL may be visualized directly
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In addition, the ACL appears slack when the PCL is torn; known as the “sloppy” or “slack” ACL sign ( Figure 33-4 A )
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This is secondary to posterior tibial subluxation owing to the loss of support from a torn PCL and can be restored with an anterior translation force ( Figure 33-4 B )
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The practitioner may also observe signs of damage secondary to the PCL injury such as altered tibial/femoral contact points, anterior horn meniscal tears, and degenerative changes
FIGURE 33-4
Arthroscopic PCL tear findings: ACL is “slack” or “sloppy” because of loss of support from the deficient PCL ( A ) and restored with an anterior translation force ( B ).
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Clinical Presentation
History
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Typical history involves a direct blow to the anterior tibia with the knee flexed or a forced hyperextension
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Pain and swelling following the injury
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Recurrent swelling or effusion
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Less likely to complain of instability compared with ACL injuries
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Instability with descending stairs, going down slopes or sudden decelerations, and also when on uneven ground.
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Athletes may complain of generalized pain around the knee, and feel that “something is not right”
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Chronic injuries tend to complain of pain on walking for prolonged periods and when coming down stairs
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Low grade/minor tears can be relatively asymptomatic → football player study found 2% of pre-draft players have PCL insufficiency
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Torg et al. found that patients with isolated PCL injuries tend to remain asymptomatic compared to those who have combined injuries because of degenerative changes in the medial/lateral compartments.
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Patients may complain of numbness, tingling, or footdrop if they have a concurrent neurovascular injury.
Physical Examination
Abnormal Findings
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Gait pattern observation
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Varus thrust gait could indicate a combined PCL/PLC (posterolateral corner) injury.
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A varus thrust possibly combined with a hyperextended knee as the patient walks
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An antalgic or quadriceps avoidance gait could indicate an ACL or combined ACL/PCL injury.
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Studies have found quadriceps strength in chronic PCL-deficient patients to be compromised at higher knee flexion angles.
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Patients tend to walk with a bent knee gait to avoid terminal hyperextension and external rotation of the tibia on the femur caused by posterior subluxation of the lateral tibial plateau.
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Classically mild joint effusion
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Misalignment of the limbs when standing and sitting with the knees flexed; important in chronic injuries
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Scars indicative of previous surgeries
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Palpation of the tibial plateau with the patient lying supine and having the knees flexed at 90°
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Anterior border of the tibial plateau should sit 1 cm anterior to the medial femoral condyle
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Grade I PCL injury → plateau still anterior
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Grade II PCL injury → plateau now flush with medial condyle
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Grade III PCL injury → plateau now posterior to condyle
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Sag test: Posterior sag of the subluxed tibia with patient’s hips flexed to 45° and knees flexed to 90° while the legs are supported ( Figure 33-5 )
FIGURE 33-5
Sag test. Patient’s hips flexed to 45° and knees flexed to 90° with the legs supported, the tibia will sag posteriorly with a PCL injury.
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Posterior sag disappears when quads flexed at 60° knee flexion and feet on table (quads active test)
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Posterior drawer test: Patient should be supine with the hips flexed to 45° and knees flexed to 90°, the examiner pushes the tibia backward ( Figure 33-6 )
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Increased laxity will be observed with a PCL injury.
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Increased posterior translation of the tibia under the femur
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3+ posterior drawer test should be considered a combined knee ligament injury until proved otherwise
FIGURE 33-6
Posterior drawer test. Patient should be supine with the hips flexed to 45° and knees flexed to 90°.The examiner pushes the tibia backward. Increased laxity will be observed with a PCL injury.
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Positive posterior shift test: Flex the hip to near 90°, then extend the flexed knee; a posteriorly subluxated tibia will reduce, causing a clunk
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Positive reverse pivot shift test: Supine patient with knee flexed to 90°, externally rotate the foot, feel for the posteriorly subluxated lateral tibial plateau under the femoral condyle and observe for abrupt reduction of the tibia as the knee is extended ( Figure 33-7 )
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Caution: This can be positive in up to 35% of normal knees, so the examiner should check the normal contralateral knee.
FIGURE 33-7
Reverse pivot shift. Supine patient with knee flexed to 90°. Externally rotate the foot, feel for the posteriorly subluxated lateral tibial plateau under the femoral condyle, and observe for abrupt reduction of the tibia as the knee is extended.
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Positive dial test: Supine patient with knees at 90°, knees placed together and both feet externally rotated, positive if difference greater than or equal to 10° to 15° for combined PCL/PCL injury at 90° ( Figure 33-8 )
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Repeat with patient prone and knees flexed at 30° and 90°
FIGURE 33-8
Dial test prone ( A ) and supine ( B ). Supine patient with knees at 90°, knees placed together and both feet externally rotated, positive if difference ≥10° to 15° for combined PCL/PCL injury at knees flexed to 90°.
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Positive external rotation-recurvatum test: Patient supine, stabilize the thigh and lift the great toe, positive if increased recurvatum, varus, and external rotation ( Figure 33-9 )
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Usually indicative of a combined posterolateral and ACL injury rather than an isolated PCL injury
FIGURE 33-9
External rotation recurvatum test. With the patient supine, stabilize the thigh and lift the great toe. Suspect combined injury if increased recurvatum.
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Inoue et al. found there were no difference in the electrical activity of the quadriceps and hamstrings in patients with chronic PCL deficiency compared with normal contralateral knee, but they did find earlier contraction of the gastrocnemius in PCL-deficient knees.
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Features of isolated PCL tears:
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Abnormal posterior laxity (use less than 8 mm as a cutoff)
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Laxity decreases with internal rotation of the tibia
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Positive sag, quads active, and posterior drawer tests
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Features of combined PCL/posterolateral corner tears
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Abnormal posterior laxity (cutoff is greater than 12 mm)
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Positive recurvatum, reverse pivot shift, posterior shift, varus stress, posterolateral Lachman, pivot shift, posterolateral drawer, and/or dial tests
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Features of combined ACL/PCL tears
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Positive Lachman and anterior/posterior drawer and pivot shift
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Posterior tibial drop back beyond flat tibial step off (15–20 mm)
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Increased varus/valgus laxity in full extension
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Almost always found combined with posterolateral or posteromedial instability
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Pertinent Normal Findings
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Isolated PCL injury
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Negative/Normal tests: Valgus and varus stress, meniscus tear assessment, Lachman and posterolateral Lachman, pivot shift, posterolateral drawer, and dial test
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Normal anterior drawer and Lachman test (unless combined injury to ACL)
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No lateral/medial gapping, unless combined injury to PLC/MCL
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Often a negative meniscus assessment test
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Quadriceps and hamstring activity are normal in PCL-deficient knees
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No numbness or tingling which would indicate a more serious injury with a neurovascular injury
Imaging
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Acute injury studies should include: AP, lateral and oblique radiographs, MRI, PCL stress radiographs
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CT has little use unless the surgeon is trying to assess the size of an avulsion fracture for operative planning or suspects a tibial plateau fracture.
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Posterior stress radiographs help demonstrate complete versus partial tears (see Figure 33-2 )
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Hewett et al. studied normal knees and those with PCL injuries.
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Normal knees have between 0 and 2 mm increased posterior translation
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Partial tears 2 to 7 mm posterior translation
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Complete tears 8 to 11 mm posterior translation
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Combined injuries will have greater than 12 mm increased posterior translation
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Patients must be relaxed while the radiographs are taken.
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“Guarding” by activating the quads can lead to false measurements
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Films should be examined closely for avulsion fractures and tibial plateau fractures.
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Pelligrini-Stieda (avulsion leading to heterotopic calcification) lesion at the femoral origin of the MCL
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Seen in chronic MCL injuries
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Lateral projections are useful to identify bony avulsions of the tibial attachment of the PCL.
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Chronic injury studies should include: Weightbearing AP, lateral at 45° flexion, Rosenberg view ( Figure 33-10 ) and standing long leg radiographs and MRI
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Radiographs should be carefully examined for tibial PCL insertion avulsion fractures that have not healed, or healed in malunion.
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In addition, the physician should look for calcified lesions like the Pelligrini-Stieda lesion at the femoral condyle, which would indicate a previous medial knee injury.
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Standing long leg radiographs are used to assess joint alignment and help the practitioner decide the need for osteotomies before reconstruction of the damaged ligaments.
FIGURE 33-10
Rosenberg view radiograph.
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Plain radiographs, including AP (weightbearing), lateral (at 45° flexion), oblique, sunrise, and Rosenberg views all may be useful.
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MRI → 97% sensitive for detecting acute PCL tears, but sometimes it can be difficult to tell if the tear is complete or partial. MRI can be inaccurate for chronic PCL injuries. This is where stress radiographs are useful.
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Great for detecting combined injuries as well as assessing other ligaments/structures in the knee and subchondral bruising or damage
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In chronic injuries, MRI of the PCL may appear normal as tears heal and scar, then the scar tissues can stretch out
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Replaced the need for bone scans in patients with chronic PCL injuries suffering from pain and instability to look for early degenerative changes in the medial and patellofemoral compartments
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Helps to influence surgical decision making
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Differential Diagnosis
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PLC injury
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Historical findings: Mechanism is typically hyperextension (contact or non-contact), direct trauma to the anteromedial knee or non-contact varus force to the knee
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Physical findings: Pain, instability, swelling, positive posterolateral drawer sign/test, recurvatum test, varus stress tests at 0° and 30°, dial test, reverse pivot shift test, and figure 4 test. Also a varus thrust gait can be seen on gait analysis
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ACL injury
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Historical findings: Mechanism is typically valgus stress, or pop occurring while cutting, changing direction, landing (hyperextension pivot)
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Physical findings: Pain, instability, swelling, positive Lachman sign/test
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MCL injury
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Historical findings: Mechanism is valgus stress ± rotational stress
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Physical findings: Pain and medial gapping with valgus stress testing; anteromedial drawer test
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Meniscal tear
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Historical findings: Mechanism is typically a sudden twist on a weightbearing knee or repeated squatting
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Physical findings: Intermittent pain at the joint line and possible joint locking, clicking, or catching. Meniscal tear assessment, Apley Test, posterior knee pain with knee flexion
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Tibial plateau fracture
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Historical findings: Mechanism is typically a valgus force with axial loading, often from a fall or landing from height
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Physical findings: Large effusion, palpable defect, varus or valgus instability, and severe pain
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Treatment
An algorithm for deciding among surgical and nonsurgical treatment options is presented in Figure 33-11 .
Nonoperative Management
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All modalities rely on physical therapy, and return to sporting activities is not typically allowed until full quadriceps strength has been restored and a firm end point on clinical exam is achieved (typically 6 to 8 months, but for elite athletes the timeframe could be as little as 6 to 8 weeks)
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Slower rehabilitation protocols than those for ACL injuries
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- 1.
Immobilize the affected limb in extension for 2 to 4 weeks using a splint with a pad placed under the tibia to counter gravity ( Figure 33-12 )
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Maintaining the tibia in the proper anatomical position is critical for maximizing healing potential.
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Immobilizing in extension takes the tension off of the anterolateral bundle.
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Physical therapy during the first 6 weeks focuses on reduction of inflammation (NSAIDs), maintaining ROM with prone passive flexion.
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Patients should be doing straight leg raises, quadriceps sets, and partial weightbearing with crutches to maintain quadriceps strength.
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Hamstring exercises should be avoided for at least 3 months.
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Quadriceps strengthening is essential, can use PT or electrical stimulation
FIGURE 33-12
Immobilizer brace for rehab patients.
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- 2.
Jung et al. put patients in a cylindrical cast for 6 weeks followed by a brace for 6 more weeks.
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All 12 weeks utilized support against posterior tibial sag.
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After 12 weeks physical therapy begins.
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Straight leg raises and quad strengthening are recommended while casted.
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After the cast is removed, patients start closed, kinetic exercises while preventing posterior displacement.
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Flexion of up to 90° is allowed for the third week after cast removal and up to 120° by 6 to 12 weeks after cast removal.
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- 3.
Quadriceps strengthening with/without activity modification
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Reduction of physical activity and/or MRI
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Jack brace ( Figure 33-13 )
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Allows full range of motion within the brace from 0° to 110° of flexion
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Maintains anteriorly directed force on the posterior proximal tibia which prevents posterior sag and allows the PCL to heal in the proper position
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Typically worn for 4 months
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Only allowed to be taken off when the knee will be in full extension with the quads contracted (like standing in a shower) or prone full knee extension
FIGURE 33-13
Jack PCL brace maintains anteriorly directed force on the posterior proximal tibia which prevents posterior sag and allows the PCL to heal in the proper position.
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Guidelines for Choosing Among Nonoperative Treatments
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An optimal set of guidelines for nonoperative management of PCL injuries has not yet been defined or agreed upon.
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Combined PCL injuries are treated surgically.
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For nonsurgical treatment, patients should meet the criteria for isolated PCL injury:
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PCL stress radiographs less than 8 mm
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Less than 5° of abnormal rotary laxity at 30° knee flexion
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No significant collateral injury causing varus/valgus laxity
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Isolated grade I or II PCL tears or a non-displaced PCL bony avulsion with a small fragment with grade I/II laxity can be treated with progressive weightbearing and rehabilitation focused on quadriceps strengthening.
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Use of a Jack brace has been shown to provide good to excellent results in this patient population.
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Isolated grade III injuries can be immobilized in extension for 2 to 4 weeks followed by progressive weightbearing and therapy.
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Therapy is focused on increasing ROM and quadriceps strengthening.
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Elite athletes or those who fail conservative therapy should be considered for surgery.
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Grade III injuries in patients with an inactive or sedentary lifestyle: Typically these patients should not have surgery and should undergo appropriate nonoperative management, including quadriceps strengthening with or without activity modification.
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Patients with grade II injuries who develop recurrent pain and swelling should reduce physical activity until the pain and swelling subside.
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May also require an MRI to gauge the status of the joint, articular cartilage, and meniscal cartilage
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Patients with chronic isolated or combined PCL injuries may require MRIs to gauge injury progression and dictate treatment modifications
Surgical Indications
Absolute
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PCL stress radiograph posterior translation greater than 12 mm
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Indicates a combined ligament injury
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Acute isolated PCL injury:
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Grade III tears with plateau posterior to condyle
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Bony avulsions that are displaced
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Significant/symptomatic laxity (not confined to PCL only)
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Associated meniscal injuries
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Especially medial meniscal root tears
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Acute combined PCL injuries:
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Combined grade III PCL/PLC or PCL/PMC injuries should be treated surgically, typically will require reconstruction via a single or double bundle method
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Multiligament repairs should be reconstructed concurrently and not as a staged procedure
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Chronic isolated PCL injury:
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Symptomatic instability/pain
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Early stages of arthrosis
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Large or displaced PCL tibial avulsions should be treated with operative fixation
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Symptomatic grade III tears
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Failure of conservative/nonoperative treatment
Relative
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Grade III tears with comorbidities
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Grade II tears in elite athletes to prevent medial and patellofemoral arthrosis and laxity following nonoperative treatment
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Small fragment bony avulsions with a high degree of laxity
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Exceptions to surgery are patients with low physical demands or medical issues that would exclude operations or anesthesia
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Aspects of History, Demographics, or Exam Findings That Affect Choice of Treatment
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Grade I and II injuries are not typically treated surgically, whereas most grade III injuries are reconstructed or repaired.
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Patient who will not comply with postsurgical protocol should not be treated surgically.
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Combined injuries found on exam are treated surgically.
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Typically require reconstruction if chronic (greater than 3 weeks)
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Not recommended to be done as a staged procedure
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Complete midsubstance tears can be reconstructed via a single bundle, double bundle, or tibial inlay technique.
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Large bony avulsion injuries or those that are displaced should be treated surgically (open reduction internal fixation).
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Studies have shown that PCL-deficient knees tend to have altered load bearing patterns and contact areas, especially in the patellofemoral and medial compartments, which could lead to degenerative joint disease and disability.
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Practitioners should be cautious when considering whether to treat patients with sedentary, inactive lifestyles surgically.
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Patients will have to adhere to a strict postoperative physical therapy protocol to achieve optimal results.
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Patients who are likely to be noncompliant should be screened accordingly.
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Aspects of Clinical Decision Making When Surgery Is Indicated
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The time frame for surgery for acute combined PLC/PCL injuries should take place within 3 weeks of the initial injury to avoid fixed posterior subluxation and capsular scarring if possible.
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Acute isolated injuries to the PCL that will require surgery are best reconstructed early.
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The location of the injury and the degree of laxity are major factors that play a role in determining the necessity of surgery.
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Large bony avulsions and combined PCL/PLC injuries should be treated early if found.
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Patients with grade I and II injuries can be managed nonoperatively, but isolated grade III injuries are controversial.
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Most surgeons believe that grade III injuries increase pressures in the medial compartment and can lead to early arthritis.
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Younger patients with grade III tears are typically managed surgically to prevent the development of arthritis even though there has been no definitive study showing it to be beneficial.
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Almost all combined grade III tears are repaired by repair/reconstruction of the damaged PCL and reconstruction/repair of the other damaged structures depending on the severity and location of the injury.
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Some patients who require surgery present with a fixed posterior subluxation.
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Typically seen in patients with a previous failed PCL reconstruction or patellar tendon harvest and a long history of PCL insufficiency
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Patients with grades I and II fixed posterior subluxations should be treated with a functional PCL brace to reposition the tibia before surgery.
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Patients with grade III fixed posterior subluxation may require more invasive procedures such as a posterior capsulotomy before having their PCL reconstructed to avoid stretching of the graft after surgery.
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Head injuries, vascular traumas, soft tissue status, and general medical comorbidities must be taken into account before deciding on the appropriate treatment
Evidence
Multiple Choice Questions
- QUESTION 1.
A 25-year-old male soccer player slid into the goalpost while making a save. He suffered a direct anterior blow to the proximal tibia of his flexed left leg. He presented to the hospital that night with pain and swelling of the left knee. He described a general feeling of “something not being right” and had difficulty walking down stairs. On clinical examination he was discovered to have a Grade III PCL tear. Which of the following is the most important aspect to evaluate in a patient presenting with an acute knee injury?
- A.
Posterior drawer test
- B.
MRI with axial cuts
- C.
Posterior knee stress radiographs
- D.
Neurovascular status
- A.
- QUESTION 2.
If a patient had suffered an isolated posterior cruciate ligament tear, which of the following abnormal motions would be seen on physical exam?
- A.
The tibia would move anteriorly in relation to the femur.
- B.
The knee would have lateral opening when a valgus stress is applied.
- C.
The tibia would move posteriorly in relation to the femur.
- D.
The knee would lock in extension.
- A.
- QUESTION 3.
Which of the following patients should not be considered for surgical repair or reconstruction of a PCL injury?
- A.
A 25-year-old elite athlete with a grade II PCL tear
- B.
A 19-year-old patient with an acute combined grade III PCL/PLC injury with hemarthrosis of the affected knee
- C.
A 35-year-old female with a large bony avulsion off the tibia
- D.
A 58-year-old obese, sedentary male with an isolated grade III tear of his PCL
- A.
- QUESTION 4.
During first 6 weeks of rehabilitation or nonoperative treatment of posterior cruciate ligament injuries, which of the following exercises should be avoided?
- A.
Isolated hamstring strengthening exercises
- B.
Straight leg raises
- C.
Electrical stimulation of the quadriceps muscles
- D.
Partial weightbearing on crutches
- A.
- QUESTION 5.
A 45-year-old male hockey player comes into the office complaining of generalized pain in his left knee after sliding into a goal post during a recreational hockey game 1 week ago. He has no numbness, tingling, or loss of sensation in the affected limb. After completing a complete physical exam, you suspect he has suffered an isolated PCL injury. If an MRI scan were unable to determine if the tear is partial or complete, which diagnostic modality would be most helpful in classifying his injury?
- A.
Tunnel view radiographs
- B.
Posterior stress radiographs
- C.
AP and lateral radiographs
- D.
CT imaging
- A.
Answer Key
- QUESTION 1.
Correct answer: D With acute knee injuries it is of vital important to determine a patient’s neurovascular status. The examiner must make certain there has been no damage to arteries or nerves which would require immediate intervention to prevent permanent loss or disability. (see Clinical Presentation )
- QUESTION 2.
Correct answer: C The tibia would move posteriorly in relation to the femur. With isolated PCL injuries, the main posterior stabilizer preventing posterior translation of the tibia is lost. In combined injuries you can see increased rotatory instability as well as medial/lateral gapping. Locking in extension/flexion is more typical of meniscal injuries and would not be expected in an isolated PCL injury. (see Clinical Presentation )
- QUESTION 3.
Correct answer: D Patients with a sedentary lifestyle, or those who are unlikely to comply with rehabilitation and postoperative protocols should not be considered for PCL reconstruction, even with grade III tears. Elite athletes with grade II tears can be considered for surgery to aid them in returning to the previous level of performance. Large bony avulsion fractures are candidates for surgery, whereas smaller avulsions can be managed conservatively. Acute combined PCL injuries are typically candidates for surgery within 3 weeks of the injury, even if hemarthrosis is present. (see Treatment )
- QUESTION 4.
Correct answer: A Isolated hamstring exercises create posterior forces on the tibia, which can stretch reconstruction grafts or reinjure partial tears. Patients should avoid isolated hamstring exercises for at least 8 weeks after injury or surgery to allow for adequate healing. Straight leg raises, electrical stimulation, and partial weightbearing on crutches are all strategic points in the initial phase of surgical rehab or conservative treatment. (see Treatment )
- QUESTION 5.
Correct answer: B Posterior stress radiographs are a helpful diagnostic tool to objectively assess PCL tears. Normal knees have between 0 and 2 mm increased posterior translation, partial tears 2 to 7 mm, complete tears 8 to 11 mm and combined injuries will have greater than 12 mm increased posterior translation. They can be very helpful when the clinical exam or an MRI is nondiagnostic. Tunnel view radiographs, AP, and lateral radiographs are all part of the imaging work-up for a suspected PCL injury, but are of no use when grading the tear. Computed tomography has little use with PCL injuries unless the surgeon is trying to assess the size of an avulsion fracture for operative planning or is looking for a tibial plateau fracture. (see Imaging )
Nonoperative Rehabilitation of Posterior Cruciate Ligament Injuries
- Robert F. LaPrade, MD, PhD
- Casey M. Pierce, MD
- Scott A. Wilkins, DPT, OCS
- Casey M. Pierce, MD
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Protect healing ligament.
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Reduce swelling and pain.
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Restore functional strength and stability to the knee.
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Initiate early activation of the quadriceps to maintain stability.
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Limit risk or reinjury.
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Help the patient adapt to daily life after injury and safely return to sports.
Phase I (weeks 0 to 4)
Protection
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Nonweightbearing (NWB) to partial weightbearing for 2 weeks
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Axillary crutches until gait is normalized
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Knee immobilizer locked in 0° extension during gait for first 1 to 2 weeks ( Figure 33-14 A )
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Pad behind tibia to avoid posterior tibial sag while at rest ( Figure 33-14 B ).
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Brace opened to 90° for sitting after 2 weeks.
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Knee ROM should be performed only in the prone position for the first week ( Figure 33-15 ).
- •
Prevents hamstring activation and posterior sag caused by gravity
FIGURE 33-15
ROM exercises in the prone position with anteriorly directed tibial translation.
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FIGURE 33-14
Knee Immobilizer locked in 0° extension ( A ) and pad behind tibia to avoid posterior tibial sag while at rest ( B ).
- •
- •
If a combined PLC and PCL injury is diagnosed, the patient should be in a functional PCL brace to better support the posterior capsule.
- •
Range of motion during therapy exercises should be limited from 45° to 90° for the first 2 weeks.
- •
This is based on biomechanical studies that show the varying loads on the PCL based on knee flexion angles and avoidance of sheer forces on the damaged PCL.
- •
| PHASE I (weeks 1 to 2 postinjury) | PHASE II (weeks 5 to 8 postinjury) | PHASE III (weeks 9 to 14 postinjury) | PHASE IV (weeks 15 to 20 postinjury) | PHASE V (weeks 21+ postinjury) |
|---|---|---|---|---|
|
|
|
|
|
Management of Pain and Swelling
- •
Vasopneumatic compression
- •
Elevation
- •
Compression bandage
- •
Cryotherapy
- •
Apply ice for 20 minutes following exercises/physical therapy
- •
- •
PRICE technique → protect, rest, ice, compress, and elevate
- •
Medications
- •
NSAIDs as needed
- •
- •
48 hours after the injury moist heat can be applied for 20 minutes at a time as needed
Techniques for Progressive Increase in Range of Motion
Manual Therapy Techniques
- •
Initially patients are immobilized to allow for early ligament healing to begin (see Figure 33-14 ).
- •
Protected prone ROM may begin right away depending on the grade of the injury or other associated injuries.
- •
Posterior sag of the tibia must be protected at all times during this phase.
- •
Once ROM is allowed, passive ROM is progressed slowly over the next 4 weeks from 0° to 120°.
- •
Knee ROM should be performed passively in the prone position (see Figure 33-15 ).
- •
Avoids activation of the hamstrings
- •
Allows compression of the tibiofemoral joint preventing posterior translation of the tibia on the femur
- •
Prevents posterior sag of the tibia on the femur
- •
- •
Passive knee flexion should be performed with a manual anteriorly directed translation force on the tibia over the femur throughout the range of motion.
- •
- •
Anteriorly directed tibial translation mobilizations may be performed in chronic injuries that have a fixed posterior translation to restore normal joint position and tibiofemoral contact points.
- •
Patellar mobilizations can be performed during the immobilization period to avoid adhesions of the patellofemoral joint.
Soft Tissue Techniques
- •
Soft tissue mobilization, trigger point release, myofascial release, and retrograde edema mobilization may be performed on the muscles and fascia around the involved limb.
- •
These techniques reduce fascia restrictions, control swelling, reduce pain, and facilitate muscle activation.
- •
To limit stress to the healing ligament, care should be taken during soft tissue techniques to avoid direct posterior pressure on the tibia or varus/valgus positioning of the limb.
- •
Stretching and Flexibility Techniques for the Musculotendinous Unit
- •
Stretching of the posterior thigh, hamstring and gastrocnemius muscles as tolerated without pain ( Figure 33-16 ).
- •
Especially warranted for those individuals demonstrating a flexed knee gait
FIGURE 33-16
Stretching exercises for the hamstring ( A ), gastrocnemius ( B ), and quadriceps ( C ).
- •
Other Therapeutic Exercises
- •
Total leg strength (TLS)
- •
Two sets of 10 to 15 repetitions for lower extremity strengthening exercises
- •
Straight leg raise in supine with brace on and locked in extension ( Figure 33-17 )
FIGURE 33-17
Supine straight leg raise with locked extension brace.
- •
Standing/side-lying hip abduction with brace on ( Figure 33-18 )
FIGURE 33-18
Side-lying hip adduction with the brace in place.
- •
Standing/prone hip extension with brace on ( Figure 33-19 )
FIGURE 33-19
Standing hip extension with the brace in place.
- •
Standing heel raises once weightbearing is allowed ( Figure 33-20 )
FIGURE 33-20
Standing heel raises: two legs ( A ) and one leg ( B ).
- •
- •
Total body strength (TBS)
- •
Upper body strengthening and core strengthening may continue throughout this phase in a nonweight-bearing position.
- •
Care must be taken to avoid bracing or stabilizing with the involved limb during upper body and core strengthening.
- •
The knee brace should be worn for safety.
- •
- •
Early TBS exercises
- •
Two sets of 8 to 12 repetitions for upper extremity and core strengthening exercises
- •
Posterior pelvic tilting with abdominal bracing ( Figure 33-21 A )
FIGURE 33-21
Posterior pelvic tilting with abdominal bracing ( A ) and with one leg lifting ( B ).
- •
Abdominal bracing with leg lifting in supine and prone ( Figure 33-21 B )
- •
Seated rows with the legs straight
- •
Seated pull downs with the legs straight
- •
- •
Rotational stresses to the core may be applied manually by the therapist and initiated in supine during Phase I.
- •
Activation of Primary Muscles Involved
- •
Quadriceps activation through quadriceps setting and progressing to straight leg raising without an extension lag
- •
Two sets of 10 to 15 repetitions
- •
This should be performed in the knee brace with pad behind tibia to avoid posterior tibia sag.
- •
Patient may progress to straight leg raise without the brace once able to perform exercise without a lag sign
- •
- •
Neuromuscular electrical stimulation may be applied to quadriceps to aid in early activation and prevent atrophy of immobilized muscles ( Figure 33-22 )
- •
Also found to be useful when applied while the patient exercises
FIGURE 33-22
Electrical stimulation pad placement on the quadriceps.
- •
Sensorimotor Exercises
- •
Once weightbearing is allowed, patients may initiate standing weight shifts with their brace on.
- •
May progress to exercises without the brace once the patient has demonstrated normal quadriceps activation, straight leg without lag sign, and can bear full weight without pain or giving way
- •
- •
Single leg exercises help to restore balance
- •
Balance exercises are progressed from eyes open to eyes closed and from stable to unstable surfaces such as foam pads.
- •
The majority of proprioceptive training will begin during Phase II.
Open and Closed Kinetic Chain Exercises
- •
OKC exercises while in brace
- •
Two sets of 10 to 15 repetitions for OKC exercises
- •
Side-lying or standing hip abduction
- •
Standing or prone hip extension
- •
Supine straight leg raises
- •
Ankle pumps
- •
- •
Once knee ROM is allowed, OKC exercises can include:
- •
Knee extension from 90° to 60° flexion to facilitate quadriceps strengthening ( Figure 33-23 )
- •
Limit knee extension to decrease forces on the patellofemoral joint and sheer forces on the healing PCL
FIGURE 33-23
OKC knee extensions from 90° ( A ) to 60° ( B ).
- •
- •
- •
CKC exercises may begin after 2 to 3 weeks or once weightbearing is allowed
- •
Limit knee extension between 70° and 30° window to limit forces on the patellofemoral joint and sheer forces on the healing PCL
- •
Early exercises
- •
Two sets of 10 to 15 repetitions for early exercises
- •
Standing heel raises
- •
Two-legged wall slides from 0° to 70° ( Figure 33-24 )
FIGURE 33-24
Two legged wall slides from 0° to 70°.
- •
Leg press at 25% body weight ( Figure 33-25 )
FIGURE 33-25
Leg presses at 45°.
- •
- •
25% body weight is a starting point for CKC exercises that may be progressed according to patient tolerance and performance of exercise at an intensity of two sets of 10 to 15 repetitions
- •
Limited to 45° knee flexion for the first week and progressed to 70° during week 2
- •
Prevents posterior sheer forces on the PCL
- •
- •
Progress to mini squats at the counter from 0° to 70°
- •
Techniques to Increase Muscle Strength, Power, and Endurance
- •
OKC and CKC exercises can be progressed according to patient tolerance and endurance
- •
Mixed CKC and OKC quadriceps will help build strength/power
- •
Single leg resisted knee exercises can start after week 1
- •
Exercises should be pain free
- •
Exercises are discontinued if pain, acute effusion, catching, or giving way is present
- •
- •
Early exercises should include high repetition and low weight resistance to target Type I endurance muscle fibers
- •
An upper body bicycle can be helpful to maintain or improve cardiovascular endurance
- •
- •
Strengthening exercises should be performed daily or every other day and monitored for signs of joint aggravation such as acute swelling/effusion and localized joint pain
Neuromuscular Dynamic Stability Exercises
- •
CKC neuromuscular stability exercises should be performed in the brace initially until normal quadriceps activation (as compared with the contralateral normal side) is achieved and the patient is able to walk without a limp.
- •
Stability exercises should progress from stable to unstable surfaces such as foam, air bladders, or wobble boards ( Figure 33-26 ).
- •
Three to five sets of 30 second intervals for stability exercises
FIGURE 33-26
Stability exercises on an air bladder ( A ), foam ( B ), and wobble board ( C ).
- •
- •
Patients may initially require upper extremity assistance to maintain balance.
- •
As function and stability progress, perturbations may be applied in random order to further challenge the neuromuscular system.
- •
Functional Exercises
- •
Step up exercises performed on a 6-inch step can begin when gait on flat ground is normalized ( Figure 33-27 ).
- •
Two sets of 10 to 15 repetitions for step up exercises
FIGURE 33-27
Step up exercises: start ( A ) and finish ( B ).
- •
- •
Exercises should be performed with the brace on and can be progressed through increased step height and from stepping up to stepping down.
- •
Walking forward and backward with the help of a mirror will help to restore proper gait mechanics once full weightbearing is allowed
Milestones for Progression to the Next Phase
- •
Minimal or decreased knee swelling
- •
Ability to straight leg raise without extension lag
- •
Gait is normalized without crutch assistance
- •
Patient is able to walk up and down steps without limp
- •
Knee ROM to 120° flexion
Phase II (weeks 5 to 8)
Protection
- •
Transition to PCL support brace
- •
Used for support during light activities and pain free return to sports activities
- •
- •
Discontinue the use of crutches
- •
Weightbearing as tolerated
- •
Management of Pain and Swelling
- •
Similar to Phase I
- •
Vasopneumatic compression
- •
Elevation
- •
Compression wrap
- •
Cryotherapy
- •
Apply ice for 20 minutes following exercises/physical therapy
- •
- •
PRICE technique → protect, rest, ice, compress, and elevate
- •
Medications
- •
NSAIDs as needed
- •
- •
Moist heat can be applied for 20 minutes at a time as needed
Techniques for Progressive Increase in Range of Motion
- •
Progress toward full PROM starting at week 4 followed by full AROM once isolated hamstring contractions are allowed at 6 weeks.
- •
Posterior sag of the tibia must continue to be avoided through an anteriorly directed force applied to the tibia during all ROM exercises and avoidance of isolated hamstring activation.
Manual Therapy Techniques
- •
Anterior tibial translation mobilizations and patellar mobilizations as needed to restore normal tibiofemoral contact points and prevent fixed posterior translation of the tibia
- •
Continued patellar mobilizations may be required as full knee flexion ROM is achieved
Soft Tissue Techniques
- •
Continue as necessary from Phase I.
Stretching and Flexibility Techniques for the Musculotendinous Unit
- •
Passive range of motion (PROM) performed in a prone position, or in a supine position with anteriorly directed force applied to the posterior tibia during flexion to achieve the goal of full PROM
- •
Hamstring and calf stretching as needed
- •
Begin prone quad stretching as full knee flexion ROM is achieved
Other Therapeutic Exercises
- •
Weight or resistance bands may be added proximal to the tibia as strength allows
- •
TLS should be performed to fatigue every other day
- •
TLS exercises should continue to include:
- •
Quadriceps sets
- •
Supine straight leg raises into hip flexion
- •
Side-lying hip abduction
- •
Prone hip extension
- •
Side-lying hip “clamshell” external rotation ( Figure 33-28 ), and standing single leg heel raises
FIGURE 33-28
Side-lying external rotation (clamshell): start ( A ) and finish ( B ).
- •
Each exercise should be performed three times per day to fatigue
- •
- •
Stationary biking for ROM may begin once 105° of knee flexion is achieved ( Figure 33-29 )
- •
Seat height should be set so that the lower leg should have the knee slightly flexed at bottom dead center of the pedal stroke
- •
The foot should be placed slightly forward on the pedal (without toe clips) to minimize hamstring activity
- •
Start with no resistance
- •
Progress from 5 minutes to 20 minutes as strength permits
FIGURE 33-29
Proper leg placement on a stationary bike. To avoid activation of the hamstrings, the patient should ride the bike with the seat set to allow the knee to flex slightly ( A ) and the feet slightly forward on the pedals ( B ).
- •
- •
Core stability exercises may now incorporate the use of the lower body for stabilization:
- •
Two sets of 10 to 15 repetitions for core stability exercises
- •
Isometric hold exercises such as planks may be performed in two to three sets of 30- to 60-second hold intervals
- •
- •
Standing isometric side planks and side-lying planks
- •
Bridging progression
- •
Swiss ball work
- •
- •
Patients should avoid kneeling on the affected limb.
- •
Quadruped strengthening exercises are avoided.
- •
- •
Isolated hamstring activation is not allowed; therefore, stability exercises such as 90/90 bridging or heel digs must also be avoided.
- •
TBS exercises can include upper body strengthening in weightbearing with brace on for protection.
- •
Patients should maintain an athletic stance with equal weight distribution throughout the lower extremities during upper body exercises.
- •
Resistance should be limited to levels conducive to proper form throughout the upper and lower body.
- •
Activation of Primary Muscles Involved
- •
Quadriceps
- •
Gluteal muscles
- •
Gastrocnemius
Sensorimotor Exercises
- •
Weight shifting and single leg stance exercises can be progressed from flat ground to unstable surfaces such as foam pads, half-foam roller, rocker boards, and air bladders
- •
Two to three sets of 30- to 60-second hold intervals for sensorimotor exercises
- •
- •
Emphasis is placed on maintaining neutral knee alignment and athletic stance during balance exercises
- •
Exercises should be performed with brace on for additional safety
- •
Balance exercises can be further progressed by closing the eyes or applying manual perturbations
- •
Single leg exercises should be increased
Open and Closed Kinetic Chain Exercises
- •
Open kinetic chain knee extension for quadriceps strengthening may begin at the end of week 2 and continue throughout rehabilitation, ranging from 70° to 30° of extension, in a sitting position
- •
Open kinetic chain knee flexion and isolated hamstring activation is not allowed until after week 6
- •
When starting leg curls/isotonic hamstring curls, range only from 0° to 70° and begin with very light resistance
- •
- •
Supine straight leg raise, side-lying hip abduction, prone hip extension, side-lying hip external rotation (clamshell) OKC strengthening should continue throughout Phase II
- •
CKC exercises can be increased from Phase I (two sets of 8 to 12 repetitions)
- •
Leg press 0° to 70° increasing to 60% to 80% body weight
- •
Squats to 70° knee flexion
- •
Single leg squats to 70° flexion
- •
Forward and backward lunges ( Figure 33-30 )
FIGURE 33-30
Forward/Backward lunges.
- •
Resisted toe calf raises
- •
Step ups and step downs
- •
Single leg wall slides to 70° knee flexion
- •
- •
Techniques to Increase Muscle Strength, Power, and Endurance
- •
Exercises for endurance can be initiated as ROM and discomfort allow
- •
20- to 30-minute intervals three to five days per week at 65% to 70% of age predicted maximum heart rate
- •
Begin initially with 10 minute bouts three times per day until 20 to 30 minutes of exercises is tolerated for endurance exercises
- •
- •
Resisted cycling is progressed as endurance allows
- •
Patients should maintain greater than 80 RPMs and quadriceps should feel fatigued after cycling, not completely exhausted
- •
- •
Elliptical
- •
Stairmaster
- •
Pool running/pool program
- •
Neuromuscular Dynamic Stability Exercises
- •
Two sets of 8 to 12 repetitions for neuromuscular dynamic stability exercises
- •
Deceleration drills to teach proper landing technique should begin during Phase II
- •
Double leg landings
- •
Make sure the patient holds the landing position for 3 to 5 seconds
- •
- •
- •
Squats on a tilt board or balance ball
- •
One-legged balance throws
- •
Balance lunges on a tilt board
- •
Can increase difficulty by adding perturbations
- •
Plyometrics
- •
Two sets of 8 to 12 repetitions per exercise for plyometric exercises
- •
Deceleration/landing exercises should be mastered prior to moving on to plyometric exercises:
- •
Side to side jumps
- •
Jumping jacks
- •
Squat jumps ( Figure 33-31 )
FIGURE 33-31
Squat jumps progression.
- •
Functional Exercises
- •
Before progressing to running the patient must be able to walk aggressively at approximately 4.2 to 5.2 MPH without pain
- •
Progression of marching skipping, high knees, and bounding performed at three sets of 30-second intervals until 450 foot contacts are achieved would be equivalent to two thirds of a mile
- •
- •
Running progression should start during week 6
- •
Marching → skipping → high knees → alternate leg bounding
- •
- •
Squatting is progressed to a depth of 70° knee flexion
- •
Patients should be told to avoid excessive forward lean during squats because this increases hamstring activation relative to the quadriceps
- •
- •
Single leg squats to a depth of 70° are initiated with the patient’s back against a ball propped on the wall
- •
It is important to maintain neutral knee alignment, avoiding knee valgus or varus during squats
- •
Sport-Specific Exercises
- •
Straight line running may begin at approximately 6 to 8 weeks if swelling is eliminated, gait is normalized, there is a negative posterior sag sign, patient is pain free with up and down steps and squatting exercises
- •
Patients should run with brace on
- •
Treadmill running is preferred initially to control the consistency of running surface and allow for immediate discontinuation of exercise if pain symptoms arise
- •
Running can be advanced to outdoor running as endurance and strength allows
- •
Distance may be progressed by 15% per week
- •
If patient experiences symptoms of pain, swelling, or shifting in the knee the distance is reduced to the previous weeks distance for 2 weeks before advancing again
- •
Repeat until goal running distance is achieved
- •
- •
- •
Patients can start to gradually return to sports activities around weeks 8 to 9 if they have met the following criteria:
- •
Painless full ROM
- •
No change in laxity
- •
Adequate return of quadriceps strength has returned
- •
At least 85% to 90% compared with that of contralateral normal leg
- •
Measured by OKC and CKC knee extension exercises as well as compared by measurement around the thigh to compare muscle bulk versus the contralateral normal leg
- •
- •
Milestones for Progression to the Next Phase
- •
Full non-painful PROM by the end of week 6
- •
Improved lower extremity strength
- •
Measured against the patients starting points when rehabilitation first began
- •
- •
Single leg squat to 70° and held for 5 seconds
- •
A 5-second hold allows for local fatigue of fast twitch muscle fibers and minimize contact forces around the knee.
- •
- •
Flat ground running without asymmetry
- •
Negative posterior sag sign
- •
Patient supine, knees flexed at 90°
- •
Practitioner supports the legs and ankles and looks for the tibia to “sag” posteriorly
- •
Posterior sag indicates PCL insufficiency
- •
Positive sag sign could indicate a more severe PCL injury than first suspected and the patient may require repeat examination by the clinician/surgeon or further time spent on the exercises in the current phase
- •
- •
- •
- •
Negative quads active test
- •
Patient supine, knees flexed at 90°
- •
Practitioner supports the patient’s thigh to monitor muscle tone and stabilizes the foot with the other hand
- •
Patient attempts to slide their foot down the table
- •
A PCL deficient knee’s tibia will move anteriorly
- •
A normal knee’s tibia will move minimally
- •
- •
Phase III (weeks 9 to 14)
Protection
- •
PCL support brace to prevent posterior tibia translation
Management of Pain and Swelling
- •
Similar to Phase II:
- •
Vasopneumatic compression
- •
Elevation
- •
Compression wrap
- •
Cryotherapy as needed
- •
Should focus on icing after exercises for at least 20 minutes
- •
- •
Moist heat as needed
- •
Techniques for Progressive Increase in Range of Motion
Manual Therapy Techniques
- •
Full passive range of motion
Soft Tissue Techniques
- •
Continue those from Phase I/II as needed
Stretching and Flexibility Techniques for the Musculotendinous Unit
- •
Active range of motion (AROM) and active assisted range of motion (AAROM) continues toward full flexion, if not already achieved
- •
Stationary biking for ROM may begin once 105° of knee flexion is achieved
- •
Seat height should be set so that the lower leg should have the knee slightly flexed
- •
The foot should be placed slightly forward on the pedal (without toe clips) to minimize hamstring activity
- •
Begin with zero resistance
- •
Progress from 5 minutes to 20 minutes as strength permits
- •
Other Therapeutic Exercises
- •
Total leg strength (TLS)
- •
Two sets of 8 to 12 repetitions for lower extremity strengthening
- •
Continue quadriceps sets
- •
Straight leg raises into hip flexion, extension, abduction
- •
Resistance bands or weight should be added proximal to the knee joint as strength allows
- •
- •
Open kinetic chain knee extension from 70° to 30° in sitting position
- •
Calf raises with the knee straight
- •
Sets done slow and fast (each)
- •
- •
Double leg squats to 90 degrees flexion
- •
Single leg squats (from 0° to 70°)
- •
Leg presses
- •
Light weights (start off at 25% of body weight and maximize to 60% to 80%)
- •
Start at 25% body weight and progress as tolerated with two sets of 8 to 12 repetitions for strengthening
- •
Limit to 60% to 80% to prevent over exertion, improper form and potential injury
- •
- •
Maximum of 0° to 70° of knee flexion
- •
Activation of Primary Muscles Involved
- •
Quadriceps
- •
Gluteals
- •
Gastrocnemius
- •
Hamstrings
Sensorimotor Exercises
- •
Weight shifts on involved limb
- •
Three to five sets of 30 to 60 seconds for weight shift exercises
- •
Eyes open and eyes closed
- •
Progress to single leg stance, eyes open, on a firm surface
- •
Increase difficulty by closing eyes and adding changing to an unstable surface (i.e., cushion, foam half-roller, air bladder, wobble board, or BOSU ball)
- •
Open and Closed Kinetic Chain Exercises
- •
Two sets of 8 to 12 repetitions for OKC and CKC exercises
- •
OKC exercises
- •
After 8 weeks, if posterior sag sign and posterior drawer are negative, patients may begin active hamstring strengthening
- •
Hamstring strengthening should be initiated in CKC hamstring dominate exercises such as “good morning” exercises ( Figure 33-32 ) and may progress to more isolated hamstring activation such as supine heel digs or eccentric rollouts on a Swiss ball ( Figure 33-33 )
- •
- •
