New systematic review and meta-analysis comparing cementless and cemented fixation in total knee arthroplasty (TKA) finds more reasons to reconsider cementless fixation. Although no differences in survivorship were observed at minimum 2 years follow-up, the cementless group demonstrated significantly higher Knee Society function scores (KSS function) (p = 0.004), and fewer manipulations under anaesthesia (MUA) (p = 0.007) than the cemented group. (1)

Patients undergoing TKA are becoming younger and younger, and it has been predicted that more than half of all patients receiving a TKA will be younger than 65 years by 2030.1 This has generated a renewed interest in cementless TKA, where it has been suggested that biological fixation can help prevent osteolysis and the risk of aseptic loosening in younger patients. This study was intended to compare the rate and reasons for revision, functional recovery and the complication rates between cementless and cemented TKA. (1)

A search for randomised controlled trials and prospective/retrospective observational studies with more than two years follow-up was conducted in the PubMed, EMBASE, Cochrane and Web of Science databases in September 2019. This search identified 26 studies that met the inclusion criteria, 11 RCTs and 15 non-RCTs, including 2,369 patients in the cementless TKA group and 2,654 patients in the cemented group. The length of follow-up ranged from 2 to 16.6 years. (1)

Pooled results indicated that there was no significant difference in the revision rate (p = 0.55) between the two groups. The most common causes of revision were aseptic loosening, followed by periprosthetic joint infection (PJI). Pooled results showed no significant difference in the rate of aseptic loosening (p = 0.88) or PJI (p = 0.45) between the groups. Similar results for the two groups were also observed for the Knee Society knee score (p = 0.42), the Oxford Knee Score (p = 0.27) and Range of Motion (p = 0.28). The rate of DVT did not differ either (p = 0.44). (1)

Further analysis revealed that in studies of more than 2 years and less than 5.5 years follow-up, cementless TKA demonstrated improved survivorship over cemented fixation. The authors suggested that a relatively longer follow-up is needed to reveal the true differences in revision rates between these two methods of TKA fixation. Consistent with this finding was the observation of lower rates of aseptic loosening in the cementless group in studies with a follow-up of more than 2 and less than 5 years. As other causes of revision did not differ within this timeframe, the authors suggested that aseptic loosing is more common at the bone-cement interface. (1)

The authors also noted that the length of follow-up in studies reporting on KSS function were all more than 8.5 years, while those reporting on MUA followed patients for more than 5 years. As a result, they suggested “it could be concluded that cementless fixation might present long-term advantages regarding the functional recovery.” (1)