The effect of debridement performed before capsular plication on biomechanical properties of the knee joint capsule: an experimental study in rabbits

Abstract

The purpose of this study was to evaluate early postoperative biomechanical changes in plicated joint capsules and to determine the effect of debridement to create a bleeding inner capsular surface on the healing process. Fifty-four mature New Zealand white rabbits were used. Plication was performed in unilateral medial knee joint capsules of 48 rabbits either alone (n=24) or following debridement (n=24) to create a bleeding inner capsular surface. Six rabbits remained untreated for the control group. The operated knee joints were immobilized in flexion postoperatively. The rabbits from the two study groups were sacrificed in groups of six immediately after operation, in the first, second, and third weeks, of which five were evaluated in tensile tests and one was evaluated histologically. Compared to the controls, tensile strengths were significantly higher in both study groups until the third week (p<0.01), after which the difference became insignificant (p>0.05). The strength of the plicated capsules was significantly higher in the first week in both study groups than those measured in subsequent weeks (p<0.01), whereas similar tensile strengths were recorded in the second and third weeks (p>0.05). Compared to its absence, the use of debridement was associated with a significantly lower strength in the first week (p<0.01), but this difference was not observed afterwards (p>0.05). Histological findings were similar in the two study groups and were characterized by healing with increased fibrosis starting from the first week. A plicated capsule would not be weaker than an intact one. Our findings do not favor debridement for a more rapid and better healing process. Rather, it might have adverse effects on the biomechanical properties of the capsule.