LOP is associated with a postoperative residual tibiofemoral
Lateral compartment osteoarthritis progression (LOP) is a major complication after Oxford mobile-bearing unicompartmental knee arthroplasty (OUKA). This study aimed to identify the association between tibiofemoral subluxation (TFS) and LOP after OUKA.

The study included 201 patients who underwent medial OUKA. 15 showed increases in LOP of at least two Kellgren–Lawrence grades after surgery [progression (P) group], while the others had no progression. TFS was measured on preoperative full leg weight-bearing radiographs, valgus stress radiographs and postoperative plain radiographs.

--The P group had significantly higher TFS values on preoperative valgus stress and postoperative radiographs than the N group.

--Patients with postoperative residual TFS and postoperative valgus alignment were more likely to have LOP, but 9 of the 15 LOP patients did not show postoperative valgus alignment.

--The P group had significantly poorer postoperative OKS and a higher rate of revision.

Conclusively, OA progression in the lateral compartment after medial OUKA might be associated with postoperative residual TFS, but does not always coexist with postoperative valgus alignment. TFS with valgus stress preoperatively could be a good predictor of postoperative residual TFS and LOP.

Source: https://link.springer.com/article/10.1007/s00167-021-06729-y