The Effect Of The Difference Of Femoral Anterior Condyle Osteotomy In Total Knee Arthroplasty On The Postoperative Knee Function

Research ObjectiveThis paper was aimed at investigating the effects of the volume of the intraoperatively removed anterior femoral condyle and prosthetic anterior femoral condyle on the functions of the knee joint and patellofemoral joint after a total knee arthroplasty(TKA)and exploring their correlations by analyzing the medical data and postoperative follow-up data of patients with knee osteoarthritis undergoing TKA in the Department of Joint Surgery of Shandong Provincial Hospital from October 2017 to September 2018.The HSS score,Melbourne score of the patellofemoral joint,patellar height,patellar congruence angle,patellofemoral joint index,the rate of lateral patellar displacement and knee joint mobility were evaluated.This study was expected to provide suggestions for TKA in the treatment of osteoarthritis.Materials and MethodologyA total of 121 patients(144 knees)with knee osteoarthritis treated from October 2017 to September 2018 were selected.Among them,113 patients(128 knees)were well followed up,including 43 knees of male patients and 85 knees of female patients,aging from 58 to 83 years of age(average age = 69± 8.68 years).All the patients had knee osteoarthritis,and presented knee pain and knee dysfunction which were not improved by conservative treatments before their surgeries.The HSS scores and Melbourne scores of the patellofemoral joint were evaluated preoperatively.Patellar height,patellar congruence angle,patellofemoral joint index and the rate of lateral patellar displacement were measured by positive and lateral X-ray of the knee and axial X-ray of the patella(Merchant view;knee flexion,45°).Knee joint mobility was obtained by physical examination.The trochlear groove depth of the removed femoral anterior condyle and the thickness of sawblade used were measured intraoperatively,and h was defined as the trochlear groove depth of the removed femoral anterior condyle + sawblade thickness.Based on the h values,the diseased knees were divided into group A(h<3 mm),group B(3 mm?h? 6 mm)and group C(h<6 mm).All the patients were implanted with NexGen high-flexion stabilized knee prosthesis(Zimmer)via the medial patellar approach.Routine functional exercise of the knee was carried out after the surgeries.Outpatient follow-ups(average duration,13 months)were conducted after the surgeries to keep track of the relevant variables,including the HSS scores,Melbourne scores of the patellofemoral joints,patellar heights,patellar congruence angles,patellofemoral joint indices and the rates of lateral patellar displacement measured by positive and lateral X-ray of the knee and axial X-ray of the patella(Merchant view;knee flexion,45°),and knee joint mobility obtained from physical examination.ResultsAs mentioned,a total of 113 patients(128 knees)were well followed up,with an average follow-up duration of 13 months.The follow-up results demonstrated that knee pain was alleviated and the function of affected knees was improved in all the patients after their surgeries.Among the 128 knees,no complications,such as infection,loosening,nerve injury,and deep venous thrombosis of the lower extremities,occurred until December 2018.The results were as follows.1)Statistically significant differences were found in the HSS scores before and after the surgery in the three groups(P<0.05).The HSS scores among the three groups showed no statistically significant differences before and after the surgeries.2)The Melbourne scores of the patellofemoral joints presented statistically significant differences before and after the surgeries in the three groups(P<0.05).The Melbourne scores of the patellofemoral joints before and after the surgeries in group B and C were statistically different from those in group A(P<0.05).3)Statistically significant differences were detected in the degrees of knee joint mobility before and after the surgeries in the three groups(P<0.05).No statistically significant differences were observed in the degrees of knee joint mobility among the three groups before and after the surgeries.4)Patellar heights in group C were statistically different from those of group A and B(P<0.05),but no statistically significant difference was found between group B and the group C(P>0.05)in the same respect.The patellar congruence angles,patellofemoral joint indices,and the rates of lateral patellar displacement in group B and C were statistically different from group A(P<0.05),but no statistically significant difference between group B and the group C(P>0.05)were shown.ConclusionsTKA can significantly improve the pain and knee dysfunction caused by osteoarthritis in patients who showed no signs of improvement from the conservative treatments.After the TKA,the pains have been alleviated significantly,the knee functions have recovered well,and the patients'qualities of life have been significantly improved.The volumes of intraoperatively removed anterior femoral condyle and the thickness of prosthetic anterior condyle present no statistical effects on postoperative functions of knee joint or knee joint mobility,but have statistically significant effects on the functions of the patellofemoral joint.In other words,when the thickness of the prosthesis is larger than the trochlear groove depth of the removed bone block,the function of the patellofemoral joint reduces,and the patella becomes susceptible to undergoing a lateral displacement.