Background: Posterolateral rotatory instability is one of the most complex problems in ligamentous injuries of the knee. It represents a challenging diagnostic and therapeutic problem for the orthopaedic surgeon. We present the results of biceps tenodesis in chronic posterolateral rotatory instabilily of the knee.

Methods: In this case series we included all of the patients with positive reverse pivot shift test and prone external rotation test at least 3 weeks after their trauma. We excluded the patients with varus malalignment of the knee and concomitant anterior cruciate ligament (ACL) rupture. Biceps tenodesis (Clancy method) was performed. We did not reconstruct posterior cruciate ligament (PCL) if its insufficiency was diagnosed in addition to posterolateral rotatory instability. Knee scoring scale of Lysholm was used during and after follow ups. The results were statistically compared using Wilcoxon signed rank test (WSRT), paired samples t-test and friedman test. Data analysis was done using SPSS (version 11.5) and Stata (version 8) computer softwares.

Results: Our series consists of 13 patients (12 male and one female). 31% of the patients had isolated posterolateral injury and 69% of the patients had combined posterolateral and PCL injuries. The patients were between 17 to 45 years old (mean 30.25 years). Follow up was between 4 to 44 months (mean: 31 months). At the end of follow up 85% of patients had negative reverse pivot shift test. Prone external rotation test at 30° of knee flexion was negative in 92% of patients. In 92% of patients giving way was negative and in 77% of patients pain was decreased. Before operation the average Knee scoring scale of Lysholm was 73 and at the end of the follow up it increased to 85 (p value<0.001).

Conclusions: Biceps tenodesis using Clancy method is a safe, effective and reliable method in management of chronic posterolateral rotatory instability of the knee. During surgery careful exploration of the common peroneal nerve is recommended. Although we found this method effective in combined posterolateral and PCL injuries the results are much better in the cases with isolated posterolateral injuries.