Purpose: To compare the survivorship, at 15 years, of cemented versus cementless fixation of press-fit condylar primary total knee replacements.

Methods: A prospective randomised consecutive series of 501 primary knee replacements received either cemented (219 patients, 277 implants) or cementless (177 patients, 224 implants) fixation. All operations were performed either by, or under the direct supervision of, a single surgeon (PJG). Patients were followed up to establish the rate of implant survival. No patients were lost to follow up. Revision was defined as further surgery, irrespective of indication, that involved replacement of any of the three original components. Life table analysis was used to assess survival. Cox’s proportional hazards regression analysis was used to compare the cumulative survival rates for the two groups.

Results: Altogether 44 patients underwent revision surgery (24 cemented vs. 20 cementless). 11 cases were revised secondary to infection, 26 were revised due to aseptic loosening and 7 cases were revised for other reasons (instability, anterior knee pain, polyethylene wear, patellar malallignment). At time of analysis a further 7 had revision planned.

For cemented knees 15-year survival=80.7% (95%CI, 71.5–87.4), 10-year survival=91.7 (95%CI, 87.1–94.8). For cementless knees 15-year survival=75.3% (95% CI, 63.5–84.3), 10-year survival=93.3% (95%CI, 88.4–96.2). There was no difference between these two groups.

When comparing the covariates (operation, sex, age, diagnosis, side), there was no significant difference between operation type (Hazard ratio=0.83 (95%CI, 0.45–1.52) p=0.545), side of operation (HR=0.58 (95%CI, 0.32–1.05) p=0.072), age (HR=0.97 (95%CI, 0.93–1.01) p=0.097), diagnosis (OA vs. non OA, (HR=1.25 (95%CI,0.38–4.12) p=0.718). However, there was a significant gender difference (Males vs. Females (HR=2.48 (95%CI, 1.34–4.61) p=0.004).

The worst case scenario was calculated to include those patients that have also been listed for revision. Cemented 15-yr survival = 78.3%, (95%CI, 68.9–85.4), cementless 15-yr survival = 72.0%, (95%CI, 59.9–81.5).

Conclusion: This single surgeon series, with no loss to follow up, provides reliable data of the revision rates of the most commonly used total knee replacement. The survival of the press-fit condylar total knee replacement remains good at 15 years irrespective of the method of fixation. This information is useful for strategic health authorities when establishing future requirements for revision knee surgery.

We report the long-term survival of a prospective randomised consecutive series of 501 primary knee replacements using the press-fit condylar posterior cruciate ligament-retaining prosthesis. Patients received either cemented (219 patients, 277 implants) or cementless (177 patients, 224 implants) fixation. Altogether, 44 of 501 knees (8.8%) underwent revision surgery (24 cemented vs 20 cementless). For cemented knees the 15-year survival rate was 80.7% (95% confidence interval (CI) 71.5 to 87.4) and for cementless knees it was 75.3% (95% CI 63.5 to 84.3). There was no significant difference between the two groups (cemented vs cementless; hazard ratio (HR) 0.83, 95% CI 0.45 to 1.52, p = 0.55). When comparing the covariates there was no significant difference in the rates of survival between the side of operation (HR 0.58, p = 0.07), age (HR 0.97, p = 0.10) and diagnosis (HR 1.25 p = 0.72). However, there was a significant gender difference, with males having a higher failure rate with cemented fixation (HR 2.48, p = 0.004). Females had a similar failure rate in both groups.

This single-surgeon series, with no loss to follow-up, provides reliable data of the revision rates of one of the most commonly-used total knee replacements. The survival of the press-fit condylar total knee replacement remained good at 15 years, irrespective of the method of fixation.

The role of modular tibial implants in total knee replacement is not fully defined. We performed a prospective randomised controlled clinical trial using radiostereophotogrammetric analysis to compare the performance of an all-polyethylene tibia with a metal-backed cruciate-retaining condylar design, PFC-∑ total knee replacement for up to 24 months. There were 51 patients who were randomised into two treatment groups. There were 10 subsequent withdrawals, leaving 21 all-polyethylene and 20 metal-backed tibial implants. No patient was lost to follow-up. There were no significant demographic differences between the groups. At two years one metal-backed implant showed migration > 1 mm, but no polyethylene implant reached this level. There was a significant increase in the SF-12 and Oxford knee scores after operation in both groups.

In an uncomplicated primary total knee replacement the all-polyethylene PFC-∑ tibial prosthesis showed no statistical difference in migration from that of the metal-backed counterpart. There was no difference in the clinical results as assessed by the SF-12, the Oxford knee score, alignment or range of movement at 24 months, although these assessment measures were not statistically powered in this study.

We have carried out a long-term survival analysis of a prospective, randomised trail comparing cemented with cementless fixation of press-fit condylar primary total knee replacements. A consecutive series of 501 replacements received either cemented (219 patients, 277 implants) or cementless (177 patients, 224 implants) fixation.

The patients were contacted at a mean follow-up of 7.4 years (2.7 to 13.0) to establish the rate of survival of the implant. The ten-year survival was compared using life-table and Cox’s proportional hazard analysis.

No patient was lost to follow-up. The survival at ten years was 95.3% (95% CI 90.3 to 97.8) and 95.6% (95% CI 89.5 to 98.2) in the cemented and cementless groups, respectively. The hazard ratio for failure in cemented compared with cementless prostheses was 0.97 (95% CI 0.36 to 2.6). A comparison of the clinical outcome at ten years in 80 knees showed no difference between the two groups.

The survival of the press-fit condylar total knee replacement at ten years is good irrespective of the method of fixation and brings into question the use of more expensive cementless implants.