Early Treatment of Knee Dislocations 

Bruce A. Levy, M.D.
Mayo Clinic, Rochester, MN

The dislocated knee is a limb-threatening injury with a significant rate of neurovascular compromise. Optimal treatment strategies remain highly debated.

First and foremost, it is important to recognize that a knee dislocation has occurred as the vast majority present after spontaneous reduction. For example, a patient may present to the emergency room with normal X-rays and a massively swollen knee with gross instability. This clinical scenario should allude the physician to the possibility of a knee dislocation.


 

Levy_Figure_1
Figure 1: Photograph demonstrating Doppler probe measurement of the systolic pressure at the dorsalis pedis artery to determine the ankle-brachial index.

Thorough vascular assessment is probably the most important first step to the management of these injuries. Recently, several authors have demonstrated that serial physical examination alone is safe1,2. However, it is also recognized that normal and symmetric pulses may be present with a complete popliteal artery occlusion secondary to collateral flow. At our institution, we perform ankle-brachial indices (ABIs) on every patient who presents to the emergency room with a diagnosis or presumption of a knee dislocation. The ABI is a non-invasive screening tool that is easy to perform in the acute setting3.

ABI =        Doppler systolic arterial pressure in injured limb (ankle)____
                 Doppler systolic arterial pressure in uninjured limb (brachial)

Mills et al., in a study of 38 patients, have shown that the risk of a significant vascular injury with an ABI greater than 0.9 is essentially 0%4. If patients have an abnormal ABI, then we perform further vascular screening with arterial duplex ultrasound. If the ultrasound is equivocal or non-diagnostic, then we proceed with computerized tomography arteriography (CTA). The advantage of CTA compared to conventional arteriography is that the contrast is injected into the antecubital fossa as opposed to the groin and requires less than ¼ the radiation5.

A thorough neurologic exam is also important as the risk of peroneal nerve injury is noted to be approximately 25%6. Chronic peroneal nerve palsy, even after a successful multiligament knee reconstruction, can cause significant functional impairment. Conventional treatment consists of neurolysis, nerve grafting, and tibial tendon transfers, all with moderate success. More recently, at our institution, we have been performing direct nerve transfer from a healthy motor branch of the tibial nerve to the healthy distal portion of the injured peroneal nerve7. Our preliminary results are encouraging, but our outcomes have yet to be published.

Currently, there is a paucity of data in the literature to help guide treatment strategies with regard to ligament repair/reconstruction. We recently performed an evidence-based systematic review, specifically addressing three areas: 1) surgical versus nonoperative treatment, 2) repair versus reconstruction of injured ligamentous structures, and 3) early versus late surgery of damaged ligaments. Our review demonstrated that early operative treatment of the multiligament-injured knee yielded improved functional and clinical outcomes compared with nonoperative management or delayed surgery. Repair of the posterolateral corner (PLC) may yield higher revision rates compared with reconstruction8. In our own series of repair versus reconstruction of the fibular collateral ligament (FCL)/PLC, we observed a 40% failure rate with repair alone compared to a 6% failure rate with reconstruction, p = 0.049. Numerous reconstruction techniques for the FCL/PLC have been reported with varying degrees of success10,11. Laprade et al. have popularized the "anatomic" reconstruction, which hopefully will lead to improved patient outcomes12.

Levy_Figure_2
Figure 2: Arthroscopic view of the ACL and PCL grafts after fixation.

With regard to the medial collateral ligament (MCL)/posteromedial corner (PMC), the decision to repair versus reconstruct is even less clear. A recent systematic review on the surgical management of the MCL in the setting of the multiligament-injured knee demonstrated satisfactory results in both repair and reconstruction groups. In this review, only eight studies in the English literature met inclusion criteria, and no studies directly compared repair to reconstruction13. Recently, Stannard et al. presented 73 multiligament-injured knees, comparing MCL/PMC repair to reconstruction. This was a prospective but non-randomized series. They found a 20% failure rate in the repair group and a 4% failure rate in the reconstruction group14. Several authors are now working on "anatomic" reconstruction techniques with encouraging preliminary results.

Most authors agree that reconstruction (as opposed to repair) of the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) is the treatment of choice. Controversy persists regarding single-bundle versus double-bundle techniques and in particular, trans-tibial versus inlay PCL reconstruction. To date, there is no clinical data to justify one technique over the other15.

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Figure 3: Anteroposterior (AP) radiograph taken after a multiligament knee reconstruction.

Performing research studies with high levels of evidence for these complex injuries is extremely difficult, predominantly due to the heterogeneity of the study group and wide variation of injury patterns/combinations. Randomized clinical trials (RCTs) may, in fact, not be feasible in light of these considerations. Recognizing the benefits of pooling data from multiple centres and the success of other Canadian orthopaedic working groups, a Knee Dislocation Study Group has been formed with members from Canada and the United States. The establishment of multicentre prospective databases may hold the key to future research endeavors and ultimately lead to improved patient outcomes.

References

  1. Miranda, F.E., et al., Confirmation of the safety and accuracy of physical examination in the evaluation of knee dislocation for injury of the popliteal artery: a prospective study. J Trauma, 2002. 52(2): p. 247-51; discussion 251-2.
  2. Stannard, J.P., et al., Vascular injuries in knee dislocations: the role of physical examination in determining the need for arteriography. J Bone Joint Surg Am, 2004. 86-A(5): p. 910-5.
  3. Levy, B.A., et al., Screening for extremity arterial injury with the arterial pressure index. Am J Emerg Med, 2005. 23(5): p. 689-95.
  4. Mills, W.J., D.P. Barei, and P. McNair, The value of the ankle-brachial index for diagnosing arterial injury after knee dislocation: a prospective study. J Trauma, 2004. 56(6): p. 1261-5.
  5. Redmond, J.M., et al., Detecting vascular injury in lower-extremity orthopedic trauma: the role of CT angiography. Orthopedics, 2008. 31(8): p. 761-7.
  6. Niall, D.M., R.W. Nutton, and J.F. Keating, Palsy of the common peroneal nerve after traumatic dislocation of the knee. J Bone Joint Surg Br, 2005. 87(5): p. 664-7.
  7. Bodily, K.D., R.J. Spinner, and A.T. Bishop, Restoration of motor function of the deep fibular (peroneal) nerve by direct nerve transfer of branches from the tibial nerve: an anatomical study. Clin Anat, 2004. 17(3): p. 201-5.
  8. Levy, B.A., et al., Decision making in the multiligament-injured knee: an evidence-based systematic review. Arthroscopy, 2009. 25(4): p. 430-8.
  9. Levy, B. Repair versus reconstruction of fibular collateral ligament (FCL) and posterolateral corner (PLC) in the multiligament-injured knee. in AOSSM Specialty Day, AAOS Annual Meeting. 2009. Las Vegas, NV.
  10. Arciero, R.A., Anatomic posterolateral corner knee reconstruction. Arthroscopy, 2005. 21(9): p. 1147.
  11. Schechinger, S.J., et al., Achilles tendon allograft reconstruction of the fibular collateral ligament and posterolateral corner. Arthroscopy, 2009. 25(3): p. 232-42.
  12. LaPrade, R.F., Anatomic reconstruction of the posterolateral aspect of the knee. J Knee Surg, 2005. 18(2): p. 167-71.
  13. Kovachevich, R., et al., Operative management of the medial collateral ligament in the multi-ligament injured knee: an evidence-based systematic review. Knee Surg Sports Traumatol Arthrosc, 2009. 17(7): p. 823-9.
  14. Stannard, J. in AOSSM Annual Meeting. 2009. Keystone, CO.
  15. Levy, B.A., et al., Controversies in the treatment of knee dislocations and multiligament reconstruction. J Am Acad Orthop Surg, 2009. 17(4): p. 197-206.
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