Intra-articular adhesion reduction after knee surgery in rabbits by calcium channel blockers

Intra-articular adhesion post knee surgery is a common and serious complication. It is a challenge problem for orthopedic surgeon. Verapamil (VP), a widely applied calcium channel blocker, has been proved to be able to prevent synthesis/secretion of extracellular matrix molecules. The object of this study was to investigate the effects of VP on the prevention of joint adhesion in post-surgery rabbits.

A controlled double-blinded study was conducted in 40 healthy New Zealand white rabbits divided randomly into 4 groups according to the treatment method, with 10 in each group: 1) 1 mg/ml VP treatment group; 2) 2.5 mg/ml VP treatment group; 3) 5 mg/ml VP treatment group; 4) control group. Rabbits underwent surgery through the medial parapatellar approach and both lateral sides and the medial of the femoral condyle were surgically exposed. After treatment, the surgical limbs were subjected to extra-articular knee-joint immobilization in the full flexed position employing Kirschner wires for 4 weeks.

The knee surgery was successfully performed on all rabbits. The rabbits were killed 4 weeks post-operatively. The histological evaluation, hydroxyproline content, visual score, fibroblasts density, and vimentin expressional levels were conducted to assess the effect of VP on preventing joint adhesion.

In our rabbit model of knee surgery, intra-articular application of VP was able to decrease intra-articular adhesion formation after surgery. VP could prevent rabbit intra-articular adhesion in a dose-dependent manner and the highest concentration used in the study (5 mg/ml) proved to be the most effective.