Tibial Tubercle Development After Early Patellar Dislocation In Growing Rabbits

Objective:Patellar dislocation is a kind of more common clinical disease.TT-TG(Tibial Tubercle-Trochlear GrooveDistance)andthe proportion of tibial tubercle lateralization is patellofemoral joint imaging measurement of two important indicators.in clinical research,researchers found most patients who suffer patellar dislocation combine with TT-TG and tibial tubercle lateralization abnormal.we recently found that early patellar dislocation could lead to femoral trochlear dysplasia in the New Zealand developmental rabbits.To investigate the effects of early patella dislocation on the tibial tubercle location.Methods:Sixty knees from 40 one-month-old New Zealand white rabbits were randomly divided into two groups(N=40 knee/group).Group a involved the in the left knees as a control group to which nopatellar dislocation surgical procedures.Group b in the right knee underwent patellar dislocation surgery.(xylazine at doses of 20 mg/kg and 5 mg/kg bodyweight into ear vein.After anesthesia,skin preparation(shaving the surgical area),iodophor disinfection area,a total of three times,sterile cloth shop alone.The midline skin incisions were performed in the both knees of rabbits and then skin and subcutaneous tissues were dissected medially to expose the joint capsule of patella and its retinaculum with carefully procedure and avoiding damage nerve blood vessels.Postoperative all experimental rabbit single cage to feed in the same environment,allows free activities of rabbits in the cage.All rabbits were received 0.05 mg/kg of buprenorphine by intramuscular injection twice-a-day for three days to relieve pain and 10 mg/kg of ciprofloxacin by oral prophylaxis antibiotic once a day for two days after surgery.In order to prevent post-surgical adhesion and stiffness,the rabbits were exercised twice-a-day for 15 min.After surgery three days,to avoidarticular adhesion,we began to pushthe rabbit knee joint take some activities.CT scanning the rabbits(flexion 0°)was performedbefore operation and at the sixth month after surgery,the measurements included the tibial tuberosity-trochlear groove distance(TT-TG)and Tibial tubercle lateralization.Results:There was not significantly different with the both groups in the TT-TG and Tibial tubercle lateralization pre-operative.However,the mean TT-TG of Group a(no dislocation of patellar)was 1.01 ± 0.36 mm at the sixth month after surgery,the group b(dislocation ofpatellar)was 2.98 ± 0.67 mm and the difference between the both groups was significant(P<0.05).The mean tibial tubercle lateralization of the both groups was 0.46 ± 0.07(group a)and 0.55±0.04(group b),respectively.The difference was significant(P<0.05).Conclusions:The early patella dislocation could lead the tibial tubercle lateralization and increase the TT-TG.As for the clinical significance,we should take attention to the adolescent with patellar dislocation and make early intervention prevent the development of dysplasia.