Working Diagnosis:
Grade 3 MCL tear, Grade 3 PCL tear

Treatment:
During the patient's procedure for reconstruction of his PCL and MCL, a high grade ACL tear was also discovered. Because of this, his mother was contacted intraoperatively and consent was provided for ACL reconstruction.

Outcome:
The patient continues to follow with orthopedics monthly.
Initially, he wore a locked brace at 0 degrees for two weeks.
Two to six weeks after surgery, his brace was advanced from 0 degrees to 90 degrees.
After 6 weeks, he was weaned off crutches and discontinued his brace.
He continued to progress with PT with the goal of returning to football at 9 to 12 months.

Author's Comments:
The initial on-field evaluation is a crucial time to truly assess an acute injury.
This case demonstrates the importance of understanding the limitations of MRI and flexible intraoperative planning.
Sensitivity, specificity, and accuracy of MRI in detecting anterior cruciate ligament tears are 91.3%, 88.2%, and 90%. For posterior cruciate ligament tears, 92.8%, 96.1%, and 95%, respectively.
All grades of isolated MCL sprains are typically treated nonoperatively.
Operative treatment of grade 3 MCL injuries is more common in the setting of multi-ligament knee injury, displaced distal avulsions, or entrapment of the torn end of the ligament.
Treatment for isolated PCL injuries is usually nonoperative as well. However, indications for operative management of grade 3 PCL injuries includes combined ligamentous injuries, isolated grade 2/3 injuries with bony avulsion, or isolated chronic PLC injuries with a functionally unstable knee.

Editor's Comments:
In addition to the posterior drawer test, PCL stability may be assessed clinically using the sag sign, where the proximal tibia rests inferior to the contralateral side, or the reverse pivot shift where the knee is slowly extended from flexion as the tibia is externally rotated and valgus stress is applied at the knee joint with a palpable clunk indicating a positive sign.
Knee dislocations are serious injuries that result in multiple ligamentous injuries. They need to be recognized as they are often associated with vascular injury to the popliteal artery or injury to the peroneal nerve. Initial evaluation should include palpation of the dorsalis pedis and posterior tibial pulses. Even with normal pulses, serial ankle-brachial index should be assessed. If decreased, angiography can assess for vascular injury.

References:
MRI evaluation of knee injury with arthroscopic correlation. (2014). Journal of Nepal Health Research Council, 26(63).
Medina O, Arom GA, Yeranosian MG, Petrigliano FA, McAllister DR. Vascular and nerve injury after knee dislocation: a systematic review. Clin Orthop Relat Res. 2014 Sep; 472(9):2621-9.

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