Cementless total knee arthroplasty may lead to higher implant survival and lower loosening rates among patients with obesity compared with cemented fixation, according to a systematic review of four retrospective studies involving 1,622 patients.
The review analyzed implant survival, complications, and clinical outcomes in patients with body mass index (BMI) ≥30 kg/m² undergoing either cemented or uncemented total knee arthroplasty (TKA) .
Among the patients, 50% received uncemented fixation. Three studies focused on individuals with class II obesity (BMI ≥35 kg/m²), and two included only those with BMI ≥40 kg/m². Cementless TKA consistently demonstrated equal or better outcomes in implant longevity and loosening risk, particularly in patients with higher BMI.
Two studies showed statistically significant survival advantages for cementless fixation. Bagsby et al reported an 8-year survival rate of 99.3% in the cementless group versus 89.7% in the cemented group (P < .001). Sinicrope et al reported 99.1% survival for cementless TKA compared with 88.2% for cemented (P = .02).
Aseptic loosening, the leading cause of TKA failure in obese patients, was more frequent in cemented implants. Bagsby et al found a 5.8% loosening rate in the cemented group and 0% in the cementless group. Sinicrope et al reported 18.8% loosening in cemented TKA versus 0.9% in uncemented.
“Cementless fixation offers comparable or superior implant survival rates and lower rates of aseptic loosening compared to cemented fixation in the short-to mid-term follow-up. Furthermore, cementless fixation may provide similar or enhanced clinical outcomes in this high-risk and growing patient population,” said Lorenzo Lo Carmine from the University of Turin, Centro Traumatologico Ortopedico (CTO), Department of Orthopaedic Surgery, Turin, Italy.
The review highlighted the role of modern implant designs using highly porous titanium and hydroxyapatite coatings, which support osteointegration and improve long-term fixation.
Infection rates did not significantly differ between fixation types. Two studies reported more infections in the uncemented group, while the other two found a higher rate in the cemented group, suggesting no consistent association between fixation type and infection risk.
Radiolucent lines (RLLs) were reported in both groups. Boyle et al observed 16.8% RLLs in uncemented implants and 11.1% in cemented ones. Only a small number of these cases were deemed concerning for loosening, and no significant clinical differences were noted.
One study found significantly better Knee Society Score (KSS), range of motion, and pain scores in patients who received cementless implants, particularly those with posterior-stabilized designs. Other studies found no significant differences in patient-reported outcomes.
The researchers acknowledged limitations, including the retrospective design of all studies, variability in patient characteristics and implant types, and inconsistent follow-up durations. They emphasized the need for high-quality prospective trials to confirm these findings.
Given the global rise in obesity and increasing demand for joint replacement, these findings may inform future decisions on fixation strategies for high-risk patients.
The authors declared no conflicts of interest.
Source: Journal of Orthopaedics