Tibial component overhang of more than 3 mm medially increases risk of short-term postoperative revision in UKA

Key findings of the study were:

• A total of 351 knees were included in this study with a minimum follow up of three years and a mean follow up of 4.8 ± 1.5 years.

• The revision rates in each group were 3.6% (minor underhang group), 2.7% (minor overhang group), and 20.9% (major overhang group) (P < 0.001).

• From the three groups’ cumulative survival rates, the major overhang group was significantly lower than the other two groups (log rank P < 0.001).

• Multivariate Cox regression showed an association between the major overhang group and implant survival rate (hazard ratio = 7.515, 95% confidence interval = 2.500–22.593, P < 0.001).

The authors concluded that – “This study found that a tibial component overhang of more than 3 mm medially increases the risk of short-term postoperative revision in UKA. The reasons for revision are generally bearing dislocation and aseptic loosening. Therefore, we recommend that surgeons should try to keep the overhang distance of tibial component relative to the tibial plateau to within 3 mm.”

Further reading:

Effect of tibial component overhang on survivorship in medial mobile-bearing unicompartmental knee arthroplasty

Kanglong Wu, Guoqi Lv et al

The Knee 37 (2022) 188–195

https://doi.org/10.1016/j.knee.2022.06.011