More passive internal tibial rotation with posterior cruciate ligament retention than with excision in a medial pivot TKA implanted with unrestricted caliper verified kinematic alignment

Purpose Excision of the posterior cruciate ligament (PCL) is recommended when implanting a medial pivot (MP) total knee arthroplasty (TKA) to reduce the risk of limiting flexion by over-tensioning the flexion space. The present study determined whether PCL retention (1) limits internal tibial rotation and (2) causes anterior lift-off of the insert in 90° flexion after implantation of an MP design with unrestricted caliper verified kinematic alignment (KA). Methods Four surgeons implanted an MP TKA design with medial ball-in-socket and lateral flat tibial insert in ten fresh-frozen cadaveric knees. Before and after PCL excision, trial inserts with medial goniometric markings measured the angular I–E tibial orientation relative to the trial femoral component's medial condyle in extension and at 90° flexion, and the surgeon recorded the occurrence of anterior lift-off of the insert at 90° flexion. Results PCL retention resulted in greater internal tibial rotation than PCL excision, with mean values of 15° vs 7° degrees from maximum extension to 90° flexion, respectively (p < 0.0007). At 90° flexion, no TKAs with PCL retention and one TKA with PCL excision had anterior lift-off of the insert (N.S.). Conclusions This preliminary study of ten cadaveric knees showed that PCL retention restored more passive internal tibial rotation than PCL excision with a negligible risk of anterior lift-off. However, in vivo analysis from multiple authors with a larger sample size is required to recommend PCL retention with an MP TKA design implanted with unrestricted caliper verified KA.

An increasing trend of posterior cruciate ligament reconstruction in South Korea: epidemiologic analysis using Korean National Health Insurance System Database

Background The posterior cruciate ligament is crucial for posterior stability of the knee joint, and, as well as anterior cruciate ligament reconstruction, posterior cruciate ligament reconstruction (PCLR) has attracted interest in orthopedic literature. A few studies have investigated epidemiologic data of PCLR in Western countries. However, there has been no report on the epidemiological pattern of PCLR in the Asian population, including South Korea. Therefore, this study investigated the incidence and trends of PCLR in South Korea using the Korean National Health Insurance (NHI) System Database. Methods The data was collected by the Korean Health Insurance Review and Assessment Service (HIRA) from 2008 to 2016 in South Korea. Patients with a record of cruciate ligament reconstruction and PCLR were allocated from the database. An analysis of the total number and incidence per 100,000 people/year of PCLR procedures and other epidemiologic parameters was conducted according to sex and age. Results The incidence of PCLR procedures rose from 2.3 to 2.6 per 100,000 people (from 1101 to 1299 total cases; 13% increase) between 2008 and 2016: from 3.8 to 4.0 (from 901 to 1000) in males, and from 0.8 to 1.2 (from 200 to 299) in females. PCLR was performed more frequently in males than in females, however, the rate of increase was higher in females than males. The incidence of PCLR over 9 years was highest in patients in their 20s, followed by patients in their 40s and 30s. Conclusion The incidence of PCLR procedures increased by 13% over 9 years in South Korea. PCLR was performed approximately three times more in men than in women. The incidence of PCLR was highest in patients in their 20s, followed by those in their 40s. The current study will enhance our understanding of the epidemiology of PCLR. Study design Descriptive Epidemiology Study.