[Effectiveness comparison of partial versus intact posterior cruciate ligament-retaining in total knee arthroplasty with cruciate-retaining prosthesis].

OBJECTIVE: To compare the effectiveness of partial versus intact posterior cruciate ligament (PCL)-retaining in total knee arthroplasty (TKA) with cruciate-retaining (CR) prosthesis.
METHODS: A total of 200 patients with osteoarthritis, who met the selection criteria and proposed unilateral TKA with CR prosthesis, were included in the study and randomly assigned into two groups ( n=100). The patients were treated with intact retention of the double bundles of PCL in intact group and with partial resection of the anterior lateral bundle of PCL and the anterior bone island at the time of intraoperative tibial osteotomy in partial group. Patients with lost follow-up and re-fracture were excluded, and 84 cases in partial group and 88 cases in intact group were included in the final study. There was no significant difference between the two groups ( P>0.05) in terms of gender, age, body mass index, course and grade of osteoarthritis, preoperative varus deformity of knee joint, flexion contracture, range of motion, clinical and functional scores of Knee Society Score (KSS). The operation time, wound drainage volume during 24 hours after operation, visual analogue scale (VAS) score at 24 hours after operation, range of motion of knee joint, clinical and functional scores of KSS, and the anteroposterior displacement of knee joint at 30° and 90° flexion positions were compared between the two groups.
RESULTS: There was no significant difference between the two groups in operation time, wound drainage volume during 24 hours after operation, and VAS score at 24 hours after operation ( P>0.05). Patients in both groups were followed up after operation. The follow-up time was 25-40 months (mean, 30.2 months) in intact group and 24-40 months (mean, 31.8 months) in partial group. There was no significant difference in the range of motion and clinical scores of KSS between the two groups at 6, 12, and 24 months after operation ( P>0.05). The functional scores of KSS were significantly higher in intact group than in partial group ( P<0.05). There was no significant difference between the two groups in the anteroposterior displacement of knee joints at 30° flexion position at 6, 12, and 24 months after operation ( P>0.05). When the knee was at 90° flexion position, there was no significant difference between the two groups at 6 and 12 months after operation ( P>0.05), but the intact group was significantly smaller than partial group at 24 months after operation ( P<0.05). Postoperative incision continued exudation in 4 patients (2 cases of partial group and 2 cases of intact group), and incision debridement in 2 patients (1 case of partial group and 1 case of intact group). No prosthesis loosening, excessive wear, or dislocation of gasket was found during follow-up.
CONCLUSION: The double bundle of PCL plays an equally important role in maintaining the stability of the knee joint, and the integrity of PCL should be kept as much as possible when TKA is performed with CR prosthesis.