Lateral Retinacular Release in Total Knee Arthroplasty; Patella Resurfacing versus Retaining

ABSTRACT

PURPOSE: To investigate the rate of lateral retinacular release and the contributing factors between the patellar resur- faced total knee arthroplasty(TKA) and patellar retained TKA. MATERIAL AND METHODS: From Jan. 2003 to Jan. 2006, 179 cases(90 patella retained, PR; 89 patellar resurfaced, PS) were enrolled in this study. To investigate the contributing factors on the lateral retinacular release along the patellar replacement, the preoperative and postoperative radiographic evaluation was done. Patellar height, congruence angle and medial displacement was measured with the Merchant view. Anterior-posterior knee distance was measured at a lateral film. The statistical significance between two groups was analyzed using the student's t-test. RESULTS: Lateral retinacular release was done in 59 of 179 cases. Thirty-six cases of PR group and 23 cases of PS group were undertaken. The rate of lateral retinacular release was higher in PR group(p<0.05). The difference between preoperative and postoperative patellar height at a Merchant was 2.5, 0.5mm reduction in PS and PR group respectively. PS group showed more medial displacement(mean 2.5mm) than PR group(mean 1.2mm)(p<0.05). CONCLUSION: In PR group, higher rate of a lateral retinacular release was shown than PS group. Less reduction of patellar height and less medial displacement of patella might be related with the high rate of a lateral retinacular release in PR group.