Letter to the Editor Regarding the Article “Results of a Highly Porous Metal-Backed Cementless Patella Implant: A Minimum 5-Year Follow-Up”

We recently read an article by Baker et al entitled “Results of a highly porous metal-backed cementless patella implant: a minimum 5-year follow-up.”[ 1] We recognize and thank the authors for their contributions. The authors reviewed postoperative recovery in 125 patients who underwent cementless total knee arthroplasty using a compression-molded high-porosity metal-supported patellar component. Follow-up at 5 years suggested that these cementitious patellar components benefit rehabilitating patients undergoing total knee arthroplasty. The cementless patella component certainly has a particularly positive effect on total knee arthroplasty, but there are still some issues that need to be discussed.

First, implantation of cementless total knee arthroplasty components may have an impact on patient outcomes. Voigt et al's[2] study on total knee arthroplasty involving hydroxyapatite coating, porous coating, or a systematic review and meta-analysis of trials of the components found that hydroxyapatite-coated components were more stable after 2 years. The authors suggested that hydroxyapatite-coated components may be the implant of choice for patients over 65 years of age. This indicates that different coating types of patellar components will affect the outcome of patients undergoing cementless total knee arthroplasty. Second, the psychological and physical health of patients undergoing cementless total knee arthroplasty should also be paid attention to. Grau et al[3] used the 12 item Veterans RAND/Short Form Health Survey (VR/SF-12) scores to evaluate the impact of surgery on the physical health and mental health of patients and found that the clinical scores of patients who were followed up were improved. This shows that the VR-12/SF-12 score may have a particular relationship with rehabilitating patients undergoing total knee arthroplasty.

Baker et al also want to understand further whether the metal-supported patella component without bone cement can provide durable long-term fixations. However, there are still some things that could be improved overall. The authors pointed out in the article that there is a statistically significant difference in follow-up time between the patellar component without bone cement and the patellar component with bone cement. The follow-up period of 5 years is insufficient to draw complete conclusions on the long-term results and prognosis of surgery. Hence, the duration of follow-up needs to be further extended.[4] In addition, potential long-term complications due to complete wear of the polyethylene material in the patellar component implant should be taken seriously.[5] Also, due to individual differences, each patient's postoperative exercise volume is different. Therefore, it is more convincing to perform a statistical analysis on the postoperative exercise volume of follow-up patients. Finally, we again thank the authors for their study on cementless metal-supported patellar components in total knee arthroplasty, which provides a new theoretical basis for cementless total knee arthroplasty.

Publication History

Article published online:
18 July 2023

• References

• 1 Baker JF, Smith NS, Likine EF, Smith LS, Yakkanti MR, Malkani AL. Results of a highly porous metal-backed cementless patella implant: a minimum 5-year follow-up. J Knee Surg 2024; 37 (04) 267-274
• 2 Voigt JD, Mosier M. Hydroxyapatite (HA) coating appears to be of benefit for implant durability of tibial components in primary total knee arthroplasty. Acta Orthop 2011; 82 (04) 448-459
• 3 Grau LC, Ong AC, Restrepo S, Griffiths SZ, Hozack WJ, Smith EB. Survivorship, clinical and radiographic outcomes of a novel cementless metal-backed patella design. J Arthroplasty 2021; 36 (7S): S221-S226
• 4 Harwin SF, DeGouveia W, Sodhi N. et al. Outcomes of cementless-backed patellar components. J Knee Surg 2020; 33 (09) 856-861
• 5 Sporer S, MacLean L, Burger A, Moric M. Evaluation of a 3D-printed total knee arthroplasty using radiostereometric analysis: assessment of highly porous biological fixation of the tibial baseplate and metal-backed patellar component. Bone Joint J 2019; 101-B (7_Supple_C): 40-47