Use Of Metal Block In Total Knee Arthroplasty With Tibial Bone Defect

Objective:Bone defect is often visible in the femoral condyle or tibial plateau in Primary total knee arthroplasty, the latter is more seen. If the treatment of bone defect is not well, can cause the prosthesis support insufficient, become the hidden danger of loosening, displacement or collapse of the prosthesis. Treatment of bone defect:Bone cement filling, Impacted cancellous autograft,allograft or autograft, prosthesis with a metal block or custom-made prosthesis implantation. The purpose of this study is to discuss the application effect of treatment of tibial plateau bone defect using a metal block in primary total knee arthroplasty.Methods:From January 2012 to December 2013,in our department,7 cases (7 knees) underwent primary total knee arthroplasty using metal block to deal with bone defect of tibial plateau.Male:2,female:5,aged 49～84 years, averaged 57 years old. The preopretive diagnosis:osteoarthritis:4 cases (4 knees); rheumatoid arthritis:3 cases (3 knees); 4 cases of knee varus,3 cases of knee valgus. Preoperative there were different degrees of knee joint swelling and pain, flexion and extension limitation, weight-bearing full-length (WBFL) radiographs of lower extremities prompting knee varus or valgus deformity. Bone defect were involved in the side room, belonging to the uncontained. According to Anderson orthopedic research institute (AORI) belongs to A type Ⅱ. Antibiotic was used for the prevention of infection during the operation; Xarelto was taken orally for 2 weeks in the prevention of lower extremity deep venous thrombosis; In the second day after the operation removed the pressure dressing and drainage tube, application of arteriovenous pump promoting lower extremity venous blood backflow, using CPM for knee joint passive flexion exercises; After third days, walking with assist of an auxiliary or under family care, when the range of movement achieved 90 degrees,the patient left the hospital after taking a frontal and lateral X ray images and continue function exercise.All the cases were followed up outside the hospital for 1 year, 1,6,12 months after the operation, review the X ray and evaluate the knee joint function. X-ray consists of weight-bearing full-length (WBFL) radiographs of lower extremities, and anteroposterior (AP) and lateral views, weight-bearing full-length (WBFL) radiographs of lower extremities evaluate line of force of the lower limbs, anteroposterior (AP) and lateral views judge if there is prothesis loosening, displacement, collapse et al.. The evaluation of knee joint function by America New York hospital for special surgery, HSS score, out of 100 points, including:Excellent,greater than 85, Good in 70-84,Medium in 60-69;Poor,less than 59 points. Observe postoperative complications such as infection,postoperative lower limb thrombosis, postoperative 1 years for X-ray examination judge line of force of the lower limbs correction and whether there is prosthesis loosening, displacement, collapse, contrast preoperative and postoperative 1 year HSS knee joint score.Results:Postoperative follow-up of 1 years, the pain of patients disappeared, varus deformity were corrected, knee flexion extension function is improved significantly, after 1 and a half months without a walking aid automatic walking. No infection, lower limb thrombosis. The last follow-up X-ray views did not show any sign of the prosthesis loosening, displacement, collapse et al. Preoperative HSS score was 17 to 29, average 23 points,postoperative 68～95 average 81 points.Conclusion:In primary total knee arthroplasty, application of metal block treatment of tibial plateau bone defect, saving operation time,more convenient, better mechanical properties, operation effect is good, the pain disappeared, rectification of the force line satisfaction, flexion and extension function improved significantly, at the same time without increasing the complications rate.