**2. Indications**

The classic indications for a PCL retaining total knee arthroplasty (TKA) are fixed flexion of less than 30°, varus less than 20°, and valgus less than 25°; joint subluxation of no more than 1 cm; structurally intact PCL (**Figures 1** and **2**); and technical ability of the surgeon [1].

In our experience, we also use this type of implant even in the revision of a unicompartmental knee replacement caused by an aseptic loosening of the tibial component: with the use of a tibial stem, associated if necessary with an augment, we spare the PCL avoiding the

intercondylar notch cut: the aim to preserve more bone as possible taking into account that in the vast majorities of cases, these are young patients that will have the risk to require a

Cruciate-Retaining Total Knee Arthroplasty http://dx.doi.org/10.5772/intechopen.74024 25

Numerous retrospective studies of CR TKAs have demonstrated consistently good clinical

While first studies about old generation of CR systems showed systemically a survivorship of 90% at 10 years, new type of implant demonstrated an improved longevity to 96–100% after 10 years. National joint registries are very useful instrument to understand this phenomenon: 14th Annual report of National Joint Registry for England, Wales, Northern Ireland and the Isle of Man updated to December 31, 2016 recounts that from 2003 "More than half of all operations (56.6%) were total knee replacements which were all cemented, unconstrained and fixed, followed by 20.7% which were all cemented, posterior stabilised and fixed… Two-thirds (66.6%) of cemented implants are unconstrained (cruciate-retaining) and have a fixed bearing… The main decline in the type of primary knee surgery carried out has been in the use of all uncemented and hybrid total knee replacements over time…" (less than a third of those figures reported for the year 2003). Analyzing the risk of revisions after primary knee surgery by fixation method and constraint, it reveals how "…Cemented unconstrained, fixed bearing total knee replacement results in lower chances of revision overall compared to other combinations of constraint

results and excellent intermediate and long-term survival [2–5].

**Figure 2.** Lateral view of knee radiographs of a patient suitable for a CR-TKR.

further revision in the future.

**3. Clinical outcomes**

**Figure 1.** Anteroposterior view of full-length lower extremity radiographs of a patient suitable for a CR-TKR.

**Figure 2.** Lateral view of knee radiographs of a patient suitable for a CR-TKR.

intercondylar notch cut: the aim to preserve more bone as possible taking into account that in the vast majorities of cases, these are young patients that will have the risk to require a further revision in the future.
