Histomorphological Study On Accelerating Patella-patellar Tendon Junction (PPJ) Repair In Rabbits Using Low Intensity Pulsed Ultrasound Stimulation(LIPUS) And Functional Electrical Stimulation(FES)

Objective:This investigation will employ the established partial patellectomy model in rabbits to study the effect of Low Intensity Pulsed Ultrasound Stimulation(LIPUS) and Functional Electrical Stimulation (FES) on accelerating the Patella-Patellar tendon junction(PPJ) repair.Method:All 120 mature female(18-weeks-old)New Zealand White rabbits are used to be standard partial patellectomy model,and then divided into 4 groups randomly.GroupⅠ:control group,with no threatment;GroupⅡ:LIPUS treatment group,with LIPUS treatment starting from day 3 to end of week 6;GroupⅢ:FES treatment group,with FES treatment from week 7 to end of week12;GroupⅣ:LIPUS combined with FES threatment group,with LIPUS treatment starting from day 3 to end of week 6,then to be followed by FES treatment from week 7 to end of week 12.The scheduled time points of animal euthanization will be at week6,week12 and week18.The Patellar -Patellar Tendon(PPT) complex will be harvested and cut into sections after decalcification. H&E stained,Safranine O/fast green stained,toluidine blue stained and collagenⅡstained sections are used for histomorphology analysis.The new bone area,cartilage metaplasia area and thickness of fibrocartilage zone are measured through Image J and Advance2.0 histomophometric analysis system and then compared to each other.Result:.At week6 postoperatively:LIPUS group are significantly larger or thicker than both Control group and FES group on the newbone and cartilage metaplasia area or thickness of fibrocartilage zone(P<0.01), LIPUS group are significantly lower than both Control group and FES group on the mean gray value of newbone and fibrocartilage zone (P<0.01),so as to LIPUS group;At week12 and week18 postoperatively:LIPUS combined with FES threatment group are significantly larger or thicker than the other three groups on the newbone and cartilage metaplasia area or thickness of fibrocartilage zone(P<0.01), LIPUS combined with FES threatment group are significantly lower than the other three groups on the mean gray value of newbone and fibrocartilage zone(P<0.01),LIPUS group and FES group are both significantly larger or thicker than Control group on the newbone and cartilage metaplasia area or thickness of fibrocartilage zone(P＜0.05), LIPUS group and FES group are both significantly lower than Control group on the mean gray value of newbone and fibrocartilage zone(P＜0.05);There are not significantly(P＞0.05) when LIPUS group compared to FES group.At week6 postoperatively,the cartilage metaplasia is not significant in everygroup.Conclusion:LIPUS and FES are both beneficial to accelerate the Patella-Patellar Tendon Junction(PPJ) repair in rabbits,and LIPUS combined with FES threatment is better than LIPUS or FES threatment respectively through histomorphology analysis.