Transtibial Tunnel Posterior Cruciate Ligament Reconstruction

Transtibial Tunnel Posterior Cruciate Ligament Reconstruction

Gregory C. Fanelli

Chapter Synopsis

• The keys to successful posterior cruciate ligament (PCL) reconstruction are to identify and treat all pathology, use strong graft material, accurately place tunnels in anatomic insertion sites, minimize graft bending, use a mechanical graft tensioning device, use primary and backup graft fixation, and employ the appropriate postoperative rehabilitation program. Adherence to these technical principles results in successful single- and double-bundle arthroscopic transtibial tunnel PCL reconstruction based on stress radiography, arthrometer readings, knee ligament rating scales, and patient satisfaction measurements.

Important Points

• PCL surgical reconstructions may be unsuccessful because of failure to recognize and treat associated ligament instabilities (posterolateral instability and posteromedial instability), failure to treat varus osseous malalignment, and incorrect tunnel placement. The double-bundle double–femoral-tunnel transtibial tunnel PCL reconstruction approximates the anatomy of the PCL by reconstructing the anterolateral and the posteromedial bundles of the PCL. This double-bundle reconstruction more closely approximates the broad femoral insertion of the PCL, enhancing the biomechanics of the PCL reconstruction. Although the double-bundle double–femoral-tunnel transtibial tunnel PCL reconstruction does not perfectly reproduce the normal PCL, there are certain factors that lead to success with this surgical technique:

– Identification and treatment of all pathology (especially posterolateral and posteromedial instability)

– Accurate tunnel placement

– Anatomic graft insertion sites

– Strong graft material

– Minimization of graft bending

– Final tensioning at 70 to 90 degrees of knee flexion

– Graft tensioning with a mechanical tensioning device

– Primary and backup fixation

– Appropriate rehabilitation program

Surgical Pearls

• Creation of the posteromedial safety incision

• Elevation of the posterior capsule

• Tibial tunnel drill guide positioning

• Tibial tunnel drilling

• Inside to outside femoral tunnel double-bundle aimer positioning

• Inside to outside femoral tunnel drilling

• Graft passage

• Mechanical graft tensioning and fixation

• Additional surgery (anterior cruciate ligament [ACL] reconstruction, posterolateral reconstruction, posteromedial reconstruction)

Clinical and Surgical Pitfalls

• PCL surgical reconstructions may be unsuccessful because of the following:

– Failure to recognize and treat associated ligament instabilities (posterolateral instability and posteromedial instability).

– Failure to treat varus osseous malalignment.

– Incorrect tunnel placement.

• Neurovascular injury may occur during transtibial tunnel drilling. This is avoided by use of the posteromedial safety incision. The posteromedial safety incision enables the surgeon to do the following:

– Protect the neurovascular structures.

– Confirm the accuracy of the tibial tunnel placement.

– Facilitate the flow of the surgical procedure.

Posterior cruciate ligament (PCL) surgical reconstructions may be unsuccessful because of failure to recognize and treat associated ligament instabilities (posterolateral instability and posteromedial instability), failure to treat varus osseous malalignment, and incorrect tunnel placement.1–3 The keys to successful PCL reconstruction are to identify and treat all pathology, use strong graft material, accurately place tunnels in anatomic insertion sites, minimize graft bending, use a mechanical graft tensioning device, use primary and backup graft fixation, and employ the appropriate postoperative rehabilitation program. Adherence to these technical points results in successful single- and double-bundle arthroscopic transtibial tunnel PCL reconstruction documented with stress radiography, arthrometer readings, knee ligament rating scales, and patient satisfaction measurements.^4–10 This chapter illustrates my surgical technique of the arthroscopic double-bundle double–femoral tunnel transtibial tunnel PCL reconstruction surgical procedure.

Preoperative Considerations

History and Physical Examination

The typical history of a patient with a PCL injury includes a direct blow to the proximal tibia with the knee in 90 degrees of flexion. Hyperflexion, hyperextension, and a direct blow to the proximal medial or lateral tibia in varying degrees of knee flexion as well as a varus or valgus force will induce PCL-based multiple-ligament knee injuries. Physical examination of the injured knee compared with the noninjured knee reveals a decreased tibial step-off and a positive result of the posterior drawer test. Because concomitant collateral ligament injury is common (posterolateral and posteromedial corner injuries), posterolateral and posteromedial drawer tests, dial tests, and external rotation recurvatum tests may elicit abnormal results; varus and valgus laxity and even anterior laxity may be present.11,12 Diagnostic features of different types and combinations of PCL injuries are as follows.

Isolated Posterior Cruciate Ligament Injury

• Abnormal posterior laxity of less than 5 mm

• Abnormal posterior laxity that decreases with tibial internal rotation

• No abnormal varus

• Abnormal external rotation of the tibia on the femur of less than 5 degrees compared with the uninvolved side, tested with the knee at 30 degrees and 90 degrees of knee flexion

Posterior Cruciate Ligament Injury and Posterolateral Corner Injury

• Abnormal posterior laxity of more than 10 mm with a negative tibial step-off

• Abnormal varus rotation at 30 degrees of knee flexion—variable and depends on the posterolateral instability grade

• Abnormal external rotation thigh-foot angle of more than 10 degrees compared with the normal lower extremity, tested at 30 degrees and 90 degrees of knee flexion—If the examiner can see the difference, then posterolateral ligament injury exists.

• Posterolateral drawer test result positive

Combined Anterior Cruciate Ligament and Posterior Cruciate Ligament Injuries

• Grossly abnormal anterior-posterior tibial-femoral laxity at both 25 degrees and 90 degrees of knee flexion

• Positive Lachman and pseudo-Lachman test results

• Positive pivot-shifting phenomenon

• Negative tibial step-off (posterior sag)

• Increased varus-valgus laxity in full extension

Imaging Studies

Plain radiographs to evaluate PCL injuries include the following views:

• Anteroposterior weight-bearing view of both knees

• 30-degree flexion lateral view

• Intercondylar notch view

• 30-degree axial view of the patella

• Stress views at 90 degrees of knee flexion of both knees

Other Modalities

Magnetic resonance imaging is helpful in acute injuries, but we have found it to be less beneficial in chronic PCL injuries. Bone scan is used in patients with chronic PCL instability with pain to define early degenerative joint disease.

Indications and Contraindications

My indications for surgical treatment of acute PCL injuries include insertion site avulsions, a decrease in tibial step-off of 8 mm or greater, and PCL tears combined with other structural injuries. My indications for surgical treatment of chronic PCL injuries are when an isolated PCL tear becomes symptomatic and when progressive functional instability develops. Contraindications include poor skin condition, uncorrected bony malalignment, severe degenerative joint disease, and medical conditions that prevent surgical intervention.

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Sep 11, 2016 | Posted by admin in SPORT MEDICINE | Comments Off

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