Clinical Study Of The Effect Of Posterior Reduction Of Patellar Dislocation On Developmental Femoral Trochlear Dysplasia

Aim: Patellar dislocation is one of the common orthopedic diseases that can occur in young age and seriously affects children’s learning and daily life.If left untreasted in time,this disease will develop rapidly and may lead to knee degeneration and knee joint-related diseases.This disease has brought a lot of disease burden on patients and their family members.The causes of patellar dislocation are complex,including poor soft tissue balance and fracture dysplasia.Among patients with patellar dislocation,their femoral trochlear dysplasia is also common.The treatment methods for these patients are special.Therefore,based on previous clinical studies,this study uses cases to comprehensively explore the impact of patellar dislocation on the development of femoral trochlea.Methods: The clinical data of 14 patients with femoral trochelear dysplasis and patellar dislocation from 2010 to 2014 were reviewed.Their clinical manifestations were knee joint swelling and pain accompanied by lower limb weakness,and the positive test results of patellar extrapolation fear test.The patient received a lateral release of the medial patellar retinaculum.All patients underwent CT scan of knee joint before and after operation.The trochlear groove angle,patellar fit angle(ca),patellar tilt angle(pta)and patellar external slope(plsr)were measured in the group.TT-TG spacing.The development of femoral trochlea was recorded after patients’ operation.All patients were followed up for 1 to 5 years.The development of femoral trochlea was evaluated by 30 degree CT examination of knee flexion.The measurement was mainly based on trochlear groove angle,ca,PTA and PLSR before and after operation.Meanwhile,TT-TG spacing was also used to evaluate the development of femoral trochlea.Results: All patients underwent relaxation of lateral support band and decompression of medial support band.The follow-up visit time was 1 to 5 years.All the wounds healed in one stage without symptoms of infection or complications of patellar dislocation.Kujala’s patellofemoral instability score increased from 53.60(4.62)before surgery to 83.10(1.90)after surgery.The knee function score(Lysholm)increased from 54.20(8.02)to 81.60(3.97).The trochlear sulcus spacing(TT-TG),CA,PTA and PLSR of tibial tubercle returned to normal range after surgery.It is recommended to correct the femoral dislocation through soft tissue balance surgery to promote the normal development of the femoral facet joint.Conclusion: Femoral trochlear dysplasia can be secondary to patellar dislocation during the growth and development of femoral trochlear.Once the normal matching relationship of patellofemoral joint is restored,normal stress stimulation is transmitted to subchondral bone during knee flexion and extension,thus gradually realizing the purpose of remodeling the bone.The unhealthy trochlear groove is also stimulated by the outside world,allowing the femoral trochlea to develop steadily.