CRUCIATE RETAINING ARTHROPLASTY

Use of CR designs has increased annually since 2016 with lower revision rates compared to PS, but there are multiple strong studies to support no difference in ROM, function, or outcomes. Vertullo (2017) noted higher risk of revision after PS in comparison to CR. Three high quality studies for total ROM (van den Boom 2020, Kawakami 2015, Tanzer 2002), four high quality studies for flexion (van den Boom 2020, Kawakami 2015, Chaudhary 2008, Tanzer 2002), and two high quality studies for extension (Kawakami 2015, Chaudhary 2008) showed no difference between CR and PS. With respect to function, four high quality studies showed no difference in WOMAC Function (van den Boom 2020, Dowsey 2020, Beaupre 2016, Chaudhary 2008) and two high quality studies showed no difference in WOMAC stiffness (Dowsey 2020, Beaupre 2016) between CR and PS. 

Two high quality studies showed no difference in KSS and WOMAC scores (van den Boom 2020, Dowsey 2020) and SF-36 General Health (van den Boom 2020, Beaupre 2016). However, one high quality study favored PS for KSS (Ozturk 2016). Four high quality studies showed no difference in WOMAC Pain scores (van den Boom 2020, Dowsey 2020, Beaupre 2016, Chaudhary 2008) and one high quality study showed no difference in VAS (Ozturk 2016).

*ROM = range of motion, KSS = Knee Society Score, WOMAC = Western Ontario and McMaster University osteoarthritis Index, OKS = Oxford Knee Score, VAS = visual analogue score

Benefits/ Harms of Implementation

There are no known harms with this recommendation. Surgeons should be aware of the advantages and disadvantages of particular types of femoral implant designs. For example, difference in removal of bone and risk of intraoperative fracture during component insertion due to box size for PS versus CR.

Outcome Importance

The studies show CR and PS are comparable with excellent ROM, function, and outcomes.

Cost Effectiveness / Resource Utilization

There are no reported cost differences or resource utilization for CR versus PS.

Acceptability

This recommendation will likely be acceptable for surgeons as the decision to use CR or PS is up to them and they will have similar outcomes with either choice.

Feasibility

It is feasible that surgeons will continue to make the decision to use CR or PS in their practice based on similar outcomes between the two types of femoral implants.

Future Research

There have been a multitude of studies on CR versus PS femoral implants, but future research may focus on amount of bone loss and difficulty of revision TKA after CR versus PS. Additionally, emerging techniques outside the CR or PS classifications should be investigated through high-quality study designs.