TKA Trends: Cementless Fixation & Patellar Resurfacing Rates Shift

A subtle but significant shift is underway in total knee arthroplasty (TKA) procedures, with increasing adoption of cementless fixation and a concurrent decline in routine patellar resurfacing, according to data presented at the American Academy of Orthopaedic Surgeons (AAOS) Annual Meeting earlier this month. These trends, observed between 2012 and 2023, reflect evolving implant technology and a growing body of evidence questioning long-held surgical standards.

The analysis, based on data from nearly two million primary TKA procedures recorded in the American Joint Replacement Registry, revealed that the apply of cementless fixation rose from 1.9% in 2012 to 21.8% in 2023. Simultaneously, the rate of patellar resurfacing – a procedure where the underside of the kneecap is as well replaced with a prosthetic component – decreased from 95.9% to 87% over the same period. These changes aren’t happening in isolation; they’re part of a broader conversation about optimizing TKA for better patient outcomes and long-term durability.

Cementless Fixation: A Growing Alternative

For decades, cemented fixation has been the gold standard in TKA, relying on bone cement to secure the prosthetic components to the patient’s bone. However, cementless implants, designed with porous surfaces that encourage bone ingrowth, have gained traction. This is driven by advancements in implant design, including improved porous coatings and the use of 3D-printed titanium alloys, which offer enhanced initial stability and the potential for long-term biological fixation. Giles R. Scuderi, MD, FAAOS, vice president of the orthopedic service line at Northwell Health, explained that while cemented fixation remains reliable, the newer cementless options are proving increasingly viable.

The study also indicated comparable revision rates between cementless and cemented fixation during the study period, suggesting that the shift isn’t accompanied by an increased risk of implant failure. However, it’s important to note that long-term data – beyond the 12-year timeframe of this analysis – are still needed to fully assess the durability of cementless implants.

The Debate Over Patellar Resurfacing

Traditionally, patellar resurfacing has been routinely performed during TKA, based on the belief that it reduces the risk of anterior knee pain and improves long-term function. However, recent research has challenged this assumption. Some studies suggest that routine patellar resurfacing may not provide significant benefits for all patients and could even be associated with increased complications, such as implant loosening and stiffness. The study presented at AAOS reflects this growing trend toward a more selective approach, where patellar resurfacing is reserved for patients with specific indications, such as significant patellar cartilage loss or instability.

The decision of whether or not to resurface the patella is complex and depends on a variety of factors, including the patient’s age, activity level, and the condition of their patellofemoral joint. Surgeons are increasingly tailoring their approach to each individual patient, rather than adhering to a one-size-fits-all protocol.

Understanding the Data: Study Design and Limitations

The findings are based on a retrospective review of data from the American Joint Replacement Registry, a national database that collects information on TKA procedures performed across the United States. The study included data from 1,899,847 primary TKA procedures, with an average patient age of 67.6 years and a predominantly female cohort (58.5%).

It’s crucial to acknowledge the limitations of retrospective studies. These studies can identify trends and associations, but they cannot prove cause-and-effect relationships. For example, while the study showed an increase in cementless fixation, it doesn’t definitively prove that cementless implants are superior to cemented implants. Other factors, such as surgeon preference and implant availability, may have also contributed to the observed trend. The registry data doesn’t capture detailed information on patient-reported outcomes, such as pain levels and functional status, which would provide a more comprehensive assessment of the impact of these surgical changes.

Implications for Patients and Surgeons

These findings suggest that TKA is evolving, with surgeons increasingly embracing new technologies and techniques. Patients undergoing TKA should discuss the potential benefits and risks of both cementless fixation and selective patellar resurfacing with their surgeon to determine the most appropriate approach for their individual needs. Dr. Scuderi emphasized that both strategies appear to offer safe and effective outcomes independently, but further research is needed to determine whether their combined use leads to even better results.

The American Academy of Orthopaedic Surgeons provides resources for patients considering TKA, including information on surgical options, recovery, and potential complications. You can find more information on their website: https://www.aaos.org/. The Centers for Disease Control and Prevention (CDC) also offers guidance on preparing for and recovering from joint replacement surgery: https://www.cdc.gov/arthritis/interventions/joint-replacement/index.htm.

What Comes Next: Ongoing Research and Surveillance

The evolving landscape of TKA highlights the importance of ongoing research and surveillance. Researchers are continuing to investigate the long-term performance of cementless implants and the optimal criteria for selecting patients for patellar resurfacing. The American Joint Replacement Registry plays a vital role in this process, providing a valuable source of data for identifying trends and evaluating outcomes. Future studies will likely focus on comparing the long-term costs and benefits of different TKA approaches, as well as identifying factors that predict which patients are most likely to benefit from specific surgical techniques. The goal is to refine TKA procedures to maximize patient satisfaction and minimize the risk of complications, ensuring that individuals can return to an active and fulfilling life after surgery.