Outcomes of treatment of acute grade-III isolated and combined posterolateral knee injuries: a prospective case series and surgical technique.

Background: Few studies have reported the outcomes of surgical treatment of an acute grade-III posterolateral knee injury. Our purpose was to report the objective stability and subjective outcomes for a prospective series of patients with an acute grade-III posterolateral knee injury treated with anatomic repair and/or reconstruction of all injured structures.

Methods: A prospective study of all patients with a grade-III posterolateral knee injury treated with an anatomic repair and/or reconstruction within six weeks of injury was initiated in May 2005. International Knee Documentation Committee (IKDC) objective scores and bilateral varus stress radiographs were obtained at each visit, including preoperatively and at the final follow-up visit. In addition, all patients completed Cincinnati and IKDC subjective evaluations. All associated cruciate ligament tears were reconstructed concurrently.

Results: Twenty-nine patients (twenty-four men and five women with a mean age of twenty-seven years) (thirty knees) were enrolled in the study. Eight knees had an isolated posterolateral corner injury, ten also had an anterior cruciate ligament tear, four also had a posterior cruciate ligament tear, and eight also had tears of both cruciate ligaments. Four patients were lost to follow-up prior to two years, resulting in a final study cohort of twenty-five patients (twenty-six knees). All five IKDC objective subscores had improved significantly at the time of the final follow-up evaluation at an average of 2.4 years postoperatively. Varus stress radiographs demonstrated a significant improvement in the side-to-side difference in the lateral compartment gap, from 6.2 mm preoperatively to 0.1 mm at the time of the final follow-up. The mean Cincinnati and IKDC subjective outcomes scores improved from 21.9 to 81.4 points and from 29.1 to 81.5 points, respectively.

Conclusions: Treatment of grade-III posterolateral knee injuries with acute repair of avulsed structures, reconstruction of midsubstance tears, and concurrent reconstruction of any cruciate ligament tears resulted in significantly improved objective stability.