Legacy posterior stabilized prosthesis for valgus knee deformity：midterm follow up / 中国组织工程研究

ABSTRACT

BACKGROUND:Legacy posterior stabilized prosthesis has advantages in theoretic design,in vitro kinematics and abrasion, but it remains unclear whether its clinical outcomes for vaglus knee deformity are better than Legacy constrained condylar knee prosthesis. OBJECTIVE:To explore the midterm folow-up effect of Legacy posterior stabilized prosthesis in total knee arthroplasty in patients with valgus knee deformity. METHODS: From February 2006 to November 2013 in Department of Bone and Joint Surgery, Affiliated Hospital of Luzhou Medical Colege, total knee arthroplasty was used to treat valgus knee deformity in 33 cases (35 knees). Parapatelar medial approach was used. Precise osteotomy was utilized to correct limb alignment. Lateral soft tissue received selective release. Finaly, an equal type of Legacy posterior stabilized prosthesis (Zimmer, USA) was implanted and fixed with antibiotic bone cement. The differences in hospital for special surgery knee score, range of motion of knee, femoral tibial angle, and maximum flexion and extension angle, as wel as X-ray film results were compared and analyzed before and after replacement. The complications including deep vein thrombosis, peri-prosthetic infection, patelar clicking, unstable knee, and common peroneal nerve injury were recorded after surgery. RESULTS AND CONCLUSION: Al patients were folowed up for 24-50 months. The incision was healed in one-stage. No complications such as peri-prosthetic infection appeared. Three patients suffered from common peroneal nerve palsy, which was cured at half a year after surgery by expectant treatment such as trophic nerve. Two cases suffered from knee instability after replacement, which was improved at 1 month after external fixation with a brace. One case experienced deep vein thrombosis in the lower extremity, which was improved after treatment with low molecular weight heparin anticoagulation. During final folow-up, hospital for special surgery knee score increased from (51.85±4.15) preoperatively to (85.77±2.50) postoperatively (P < 0.01). There were excelent in 20 knees, good in 11 knees, with an excelent and good rate of 89%. X-ray films showed that hindlimb alignment was apparently corrected, prosthetic position was good, no loosening occurred. These data indicate that total knee arthroplasty, using parapatelar medial approach, obtained good correction outcomes through the accurate amputation to correct hindlimb alignment and selective release of the soft tissue with Legacy posterior stabilized prosthesis in the treatment of valgus knee deformity.