Commentary on
"Arthroscopically-Assisted Treatment of Avulsion Fractures of the Posterior Cruciate Ligament from the Tibia"
By Sung-Jae Kim, MD et al.

Commentary by William Garrett, MD, PhD*,
and Louis C. Almekinders, MD*,
University of North Carolina School of Medicine, Chapel Hill, NC

Dr. Kim and his co-workers report on their results of arthroscopically-assisted fixation and reduction methods for treatment of posterior cruciate ligament (PCL) avulsion fractures from the tibia in fourteen knees. They should be congratulated on the technique modifications that they developed and on the excellent results that they obtained at follow-up. This article makes a strong case for early fixation of PCL avulsion fractures from the tibia. The investigators only found residual instability in those knees that were treated late. They also showed that treatment for these PCL avulsion fractures can be accomplished using arthroscopic techniques rather than open, posterior approaches, as reported in most previous studies.

Several considerations should be kept in mind when using this study as a guideline for clinical practice. PCL avulsion fractures are relatively uncommon, even in a busy sports-medicine practice. Most occur as a result of high-energy trauma and concomitant injuries are common. All of the male patients in this study were involved in motor vehicle accidents, and most had associated long bone fractures and other ligament injuries. This setting suggests that many of these patients should be initially evaluated as multiple-trauma patients and not solely as patients with a knee injury. A search for associated injuries, such as a popliteal artery disruption, should precede any attempted treatment of a PCL avulsion fracture. In fact, some of these PCL injuries may have resulted from a knee dislocation at the time of injury.

When surgical treatment of the PCL injury is contemplated, the surgeon should feel comfortable with the technical aspects of the procedure, particularly if an arthroscopic technique is used. The arthroscopic methods described by Kim et al. require placement of posteromedial and posterolateral portals in addition to debridement of the septum posterior to the PCL. Obviously these approaches put peroneal and saphenous nerves, as well as the popliteal vessels and tibial nerve, at risk.

Although not reported in the study by Kim et al., compartment syndrome, as a result of extravasation of fluid during arthroscopy, is a possible complication, particularly in knees that have sustained multiple injuries. In these instances, the PCL avulsion and capsular disruption allow extravasation of irrigation fluid outside the joint. It is interesting to note that, in spite of the minimally invasive arthroscopic technique, arthrofibrosis still occurred in two knees. Therefore, considerable expertise and experience performing arthroscopy of the posterior aspect of the knee joint is needed before the methods described in this study should be used. This investigation does not prove that arthroscopically-assisted treatment of PCL avulsion fractures is associated with any better outcome compared with an open approach¹, but it is likely that the patients will experience less pain and possibly an easier rehabilitation with arthroscopic treatment. As with most arthroscopic treatment methods, however, it may be difficult to prove that the ultimate outcome was significantly improved by using the arthroscopic technique.

Finally, this investigation does not prove that PLC injuries treated in this manner have an outcome superior to that of nonoperatively treated injuries². Many or most injuries do well without surgical treatment, and surgery was quite possibly a factor in the limitation of motion in 21% of the knees. The authors have demonstrated that stability can be achieved using arthroscopic techniques in acutely treated knees. Further studies should delineate the outcome of non-operative treatment relative to that of surgical treatment. The ability of this procedure to restore PCL stability with a minimally invasive technique is promising.

*The authors did not receive grants or outside funding in support of their research or preparation of this manuscript. One or more of the authors received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity (Nike or Aircast). In addition, a commercial entity (Merck or Pfizer) paid or directed, or agreed to pay or direct, benefits to a research fund, foundation, educational institution, or other charitable or nonprofit organization with which the authors are affiliated or associated.

References

1. Seitz H, Schlenz I, Pajenda G, Vecsei V. Tibial avulsion fracture of the posterior cruciate ligament: K-wire or screw fixation? A retrospective study of 26 patients. Arch Orthop Trauma Surg. 1997;11:275-8.
2. Shelbourne KD, Davis TJ, Patel DV. The natural history of acute, isolated, nonoperatively treated posterior cruciate ligament injuries. A prospective study. Am J Sports Med. 1999;27:276-83.