Intact, pie-crusting and repairing the posterior cruciate ligament in posterior cruciate ligament-retaining total knee arthroplasty: A 5-year follow-up

BACKGROUND: The posterior cruciate ligament (PCL) is important for cruciate-retaining (CR) total knee arthroplasty (TKA). Whether the entire PCL should be retained during CR-TKA is controversial. AIM: To evaluate the clinical outcomes of PCL preservation in CR-TKA and the methods used to deal with the PCL during surgery. METHODS: A retrospective review of patients with osteoarthritis undergoing primary CR-TKA (176 patients, 205 knees) in our institution between March 2012 and March 2014 was performed. A PCL protector was used to preserve the intact PCL bone block. The status of the PCL was recorded during surgery. Intact PCL preserved, pie-crusting and repairing were used to balance the tension of the PCL. Range of motion (ROM) and the Knee Society Clinical Rating system (KSS) were evaluated preoperatively and at the endpoint of follow-up. RESULTS: The mean ROM of the knee was 103.2 ± 17.2°, KSS clinical score was 47.6 ± 9.5 and KSS functional score was 46.3 ± 11.9 before surgery. The mean ROM of the knee was 117.5 ± 9.7°, KSS clinical score was 89.2 ± 3.6 and KSS functional score was 84.6 ± 9.8 at 5 years follow-up. ROM, KSS clinical scores and KSS functional scores were significantly improved after surgery (P < 0.01). Thirty-two (23.7%) TKAs involved PCL pie-crusting and 18 (13.3%) involved PCL repair. Eighty-five (63.0%) TKAs applied standard operating procedures and preserved intact PCL. At 5 years follow-up, in the intact PCL group, the mean ROM of the knee was 118.0 ± 8.3°, KSS clinical score was 89.1 ± 3.7 and KSS functional score was 84.9 ± 9.6. In the PCL pie-crusting group, mean ROM of the knee was 114.0 ± 13.5°, KSS clinical score was 88.8 ± 3.4 and KSS functional score was 83.8 ± 10.5. In the PCL repair group, mean ROM of the knee was 120.3 ± 7.0°, KSS clinical score was 89.0 ± 3.6 and KSS functional score was 89.4 ± 4.5. There were no significant differences in ROM, KSS clinical scores and KSS functional scores among the three groups (P > 0.05). CONCLUSION: The clinical outcomes of preserving the PCL in CR-TKA are encouraging. Pie-crusting and PCL repair do not affect the function. The PCL protector effectively protected the PCL bone block.