A Retrospective Study Of The Results Of Efficacy Of Three-step Medial Release Technique In Varus Total Knee Arthroplasty With Medial Pivot Prosthesis

ObjectionTo explore in varus total knee arthroplasty with medial pivot prosthesis,the postoperative early-term efficacy by applying our algorithmic three-step medial release technique,which consists of the release of the d MCL(deep medial collateral ligament)(step 1),the release of semimembranosus(step 2)and the release of the MCL(superficial and deep medial collateral ligament)by pie-crusting(step 3)in Chinese population.MethodsFrom January 2017 to July 2017,primary TKAs with medial pivot prosthesis were performed in 100 patients at a university medical center by the same senior surgeon with six months’ follow-up.Preoperative and postoperative standing anteroposterior(AP),lateral radiograph of the knee and weight-bearing full length radiogragh of the lower extremity were checked to evaluate the arthritis grade and alignment of the knee,and KSS were recorded and made a comparison.Evaluating the postoperative satisfaction with WOMAC system and the incidence of complications.The flexion and extension gaps were considered balanced when the mediolateral gap difference was within 2mm.Gap balancing was obtained after d MCL release and bone cutting(group 1).Others still had unbalanced extension or flexion gap after the first step of the release procedure.The expansions of the semimembranosus were cut by using a electric surgical knife and the tibial insertion of the semimembranosus was completely released(step 2 of the release).The knees were balanced after the two release steps(group2).The knees remained in a tight medial gap until step 2 of the release was performed.In these knees,release of MCL by pie-crusting was done to achieve gap balance: release of the MCL by pie-crusting was performed using a 16 G syringe needle until the trial components were inserted.Results①12 patients lost follow-up,leaving 40 cases obtained only the the release of d MCL,37 cases obtained both the release of d MCL and semimembranosus,11 cases obtained all the release of d MCL,semimembranosus and release of MCL by pie-crusting.②There was no significant difference among the three groups in terms of age,BMI,preoperative range of motion,preoperative KSS,preoperative WOMAC as well as follow-up period(P>0.05).But there was a significant difference in terms of preoperative alignment(P<0.01).③There was no significant difference among the three groups in the D-value between the6 months’ follow-up and the preoperative KSS(P>0.05).④There was no significant difference among the three groups in the D-value between the6 months’ follow-up and the preoperative WOMAC(P>0.05).⑤There was no significant difference among the three groups in the alignment of the 6months’ follow-up results(P>0.05).⑥None of the knees demonstrated instability,prosthetic loosening and revision following total knee arthroplasty in the 6 months’ follow-up period.ConclusionIn varus total knee arthroplasty with medial pivot prosthesis it’s efficacious by applying our algorithmic three-step medial release technique in Chinese population.Early follow-up results showed that no instability happened.Good rehabilitative effect can be achieved after the surgery.By comparing the preoperative alignment we could see that in the case of the varus angle of knee>13.92 ± 3.9°,most of them need the release of semimembranosus on the basis of the release of d MCL;in the case of the varus angle of knee >18.53±6.03°,most of them need all the releases of d MCL,semimembranosus and MCL.In addition,the third groups need more thicker polyethylene than the other groups.