[Comparison of Clinical Influence of Intramedullary versus Extramedullary Alignment Guides on Total Knee Arthroplasty].

Unlabelled: Objective: To compare the clinical influence of intramedullary versus extramedullary alignment guides on total knee arthroplasty (TKA) in terms of alignment of the lower limbs,intraoperative tourniquet time,and postoperative complications.

Methods: We retrospectively analyzed the clinical data of 105 patients(210 knees)undergoing bilateral TKA from February 2012 to November 2013. All patients were divided to two groups:40 [age:(66.65 ± 9.57)years] were implanted using intramedullary guides on the tibia and 65 [age:(65.29±9.27)years] were implanted using extramedullary guides on the tibia. Alignment of lower limb,tibial component angle in the sagittal plane,tourniquet time,and postoperative complications were compared.

Results: The gender ratio,age,height,weight,body mass index,and preoperative alignment of lower limbs were not significantly different between these two groups (all P>0.05). The average coronal alignment of lower extremity was (179.69 ± 2.91)° in the intramedullary guides group and (178.26 ± 3.38)° in the extramedullary guides group (P=0.002). The alignment of lower limbs on neutral and valgus position were found in 68 cases(85.00%)in the intramedullary group and in 94 cases (72.31%) in extramedullary group (P=0.033) ;the tourniquet time was (79.46 ± 12.06) min in the intramedullary group and (84.68 ± 8.02) min in the extramedullary group (P=0.001); the postoperative complication rate was 6.25% in intramedullary group and 3.07% in extramedullary group (P=0.279).

Conclusion: Alignment and tourniquet time can be significantly improved by the intramedullary instrumentation,while the incidence of complications associated with intramedullary instrumentation is higher than extramedullary instrumentation.