Higher Pain Levels with Cementless vs Cemented Unicompartmental Knee Arthroplasty

Overview

This prospective registry study found that patients undergoing cementless unicompartmental knee arthroplasty (UKA) reported significantly higher activity-related pain at two and twelve months postoperatively compared to those receiving cemented UKA. Despite similar improvements in knee function and willingness to repeat surgery, cemented UKA was associated with less postoperative pain.

Background

Medial unicompartmental knee arthroplasty (UKA) can be fixed using cemented or cementless techniques, with increasing use of cementless fixation noted in recent years. Prior studies have shown comparable implant survival and patient-reported outcomes between the two methods, and some advantages such as shorter surgery duration and reduced radiolucent lines with cementless fixation. However, postoperative pain, a critical measure of surgical success for osteoarthritis patients, had not been directly compared between these fixation methods before this study.

Data Highlights

Key Findings

• Cemented UKA patients reported significantly less activity-related pain at both two and twelve months postoperatively compared to cementless UKA patients.
• No significant differences were found between groups in pain at rest or KOOS-PS scores at follow-up.
• Duration of surgery was slightly shorter for cementless UKA (mean 54 min) compared to cemented UKA (mean 58 min).
• At twelve months, over 90% of patients in both groups rated their knee function as improved and would choose to undergo surgery again.
• Subanalysis showed no evidence that a learning curve influenced the higher pain levels observed with cementless fixation.

Clinical Implications

While cementless UKA offers advantages such as shorter surgery duration and comparable functional outcomes, clinicians should be aware that patients may experience higher activity-related pain postoperatively compared to cemented UKA. This information is important for preoperative counseling and postoperative pain management strategies. Further research may be needed to optimize pain control in cementless UKA patients.

Conclusion

Cemented unicompartmental knee arthroplasty is associated with lower postoperative activity-related pain compared to cementless fixation, despite similar functional improvements and patient satisfaction. These findings highlight the importance of considering pain outcomes when selecting fixation methods for UKA.

References

1. Norwegian Arthroplasty Register 2020 -- Annual Report
2. Campi et al. 2020 -- Systematic Review of Cementless UKA
3. Mohammad et al. 2021 -- Long-term Revision Rates in UKA
4. Basso et al. 2019 -- Cementless Fixation and Implant Survival