Joint line obliquity after high tibial osteotomy: assessment and clinical implications

A valgus-producing high tibial osteotomy effectively addresses symptoms caused by medial knee osteoarthritis with varus malalignment, but increases knee joint line obliquity in the frontal plane. Surgeons face challenges in deciding whether to incorporate predicted joint line obliquity change into high tibial osteotomy planning. They need to know whether caution is warranted in patients with increased joint line obliquity and the potential impact of a prior high tibial osteotomy on the clinical outcomes of a total knee arthroplasty.

Aim of this thesis is to address the implications of knee joint line obliquity issues in patients undergoing high tibial osteotomy with medial knee osteoarthritis and varus malalignment.

This thesis proposes the medial proximal tibial angle as the preferred method for measuring knee joint line obliquity. Furthermore, the findings suggest that an increase in knee joint line obliquity does not adversely affect patient-reported outcomes, radiological progression of osteoarthritis and survival of lateral closing-wedge high tibial osteotomy at both mid-term and long-term follow-up. This thesis found that female gender and a postoperative untargeted alignment are risk factors for a conversion from high tibial osteotomy to total knee arthroplasty. Furthermore, this thesis shows that a prior high tibial osteotomy does not seem to affect patient-reported outcomes in subsequent total knee arthroplasty.

Overall, this thesis contributes to a better understanding of the clinical consequences associated with increased knee joint line obliquity after high tibial osteotomy and gives insight in results after total knee arthroplasty performed in patients who have previously undergone high tibial osteotomy.