A recent study by Kendrick, BJK et al1 compared the quality of fixation between cementless and cemented Oxford Partial Knees. The study, entitled "Cemented versus cementless Oxford unicompartmental knee arthroplasty using radiostereometric analysis. A randomised controlled trial" followed 43 patients; 21 cemented and 22 cementless.
The fixation assessment was done by a randomised controlled trial using Radiostereometric Analysis (RSA). The results found:
- No significant difference in the extent of femoral migration for either group between 1-2 years
- No femoral radiolucency seen in either group
- Tibial radiolucencies were were significantly (p = 0.02) less common with cementless fixation than with cemented components at two years.
differences were found in the migration of the cemented and
cementless tibial components. The main difference was
- Cemented component had little or no subsidence at three months
- Cementless components subsided during the first three months but stabilized after those three months
- In the second year there was no significant difference in subsidance between cemented and cementless tibial components.
The study suggests that the fixation of the cementless components is at least as good as if not better than that of the cemented implants as the second year migration of the cementless components were similar to that of the cemented.
Why Consider Cementless PKA?
- The Oxford Cementless Partial Knee has been shown to have no complete radiolucent lines, these lines can be misinterpreted to mean loosening of components which are often revised unnecessarily1
- Cementing can be a cause of failure if the cement around the femoral and tibial components is not fully removed, this can potentially cause wear or dislocation of the meniscal bearing
- Cementing takes time and costs money. In a study by Pandit et al, mean operative time with cementless Oxford was 9 minutes shorter than the cemented group of patients and there was no increase in complications with cementless Oxford2