30-Year Outcomes of a Cementless Total Knee Arthroplasty System in Patients Under 50 Years Old

Cementless total knee arthroplasty (TKA) was developed to address limitations of cemented fixation, particularly in younger, active patients. Design features aimed to enhance patellar tracking, optimize implant fit, and promote durable biologic fixation. Despite early concerns, outcome data remain limited. This study evaluated clinical and radiographic results at 30 years postoperatively.

A single surgeon performed 75 cementless TKAs in 57 patients using a cementless system. Surgery was performed in patients 50 years of age or younger, who had a mean patient age at surgery of 41 years (range, 29 to 49). The surgical approach of the lead author emphasized anatomic tibial resection along the native slope to prevent subsidence, as well as application of bone slurry to enhance bone ingrowth and osseointegration. Clinical and radiographic follow-up, including Knee Society Scores and implant survivorship, was conducted over a mean duration of 30.3 years (range, 25 to 38). Of the 57 patients and 75 TKAs, 27 patients and 34 knees remained at final follow-up.

The Knee Society Scores remained improved from 131 ± 21.9 preoperatively to 191 ± 21.3 postoperatively (P < 0.0001).Component survivorship was femoral component 100%, tibial baseplate 97.3%, tibial polyethylene 82.7%, and metal-backed patella 94.2%. Failures included two cases of tibial aseptic loosening, two infections, and three metal-backed patella failures. Polyethylene exchange was the most common secondary procedure (17.3% of knees). Radiographs showed no progressive radiolucency.

Follow up of this cementless TKA system in a young cohort demonstrated excellent 30-year survivorship. Additional randomized studies may help determine the efficacy of bone slurry on biologic fixation. Anatomic resections along the slope of the tibia and increased component coverage helped prevent tibial component subsidence. Most failures were attributed to wear of gamma-irradiated polyethylene components. The durable osseointegration and mechanical stability of the system and applied surgical techniques affirmed the viability for younger, active patients in this study cohort.