Proximal tibial osteotomy with absorbable spacer combined with fibular osteotomy has similar clinical outcomes to high tibial osteotomy in the treatment of knee osteoarthritis.

Purpose: Proximal tibia osteotomy with absorbable spacer combined with fibular osteotomy (TPOASI) is an emerging surgical technique for treating knee osteoarthritis (KOA); however, the efficacy of this procedure remains unknown. We hypothesize that TPOASI can achieve similar clinical outcomes to opening-wedge high tibial osteotomy (OW-HTO). The objective of this study is to compare the clinical results between these two procedures.

Methods: Patients who underwent TPOASI or OW-HTO from July 2016 to September 2020 were included. The following outcome parameters were determined before and after the surgery: the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the Knee Injury and Osteoarthritis Outcome Score (KOOS), the visual analogue scale of pain, the Intermittent and Persistent Osteoarthritis Pain Scale, femorotibial angle, and post-operative complications.

Results: In total, 209 cases were analyzed (102 in TPOASI group; 107 in OW-HTO group) with 3.1 years average follow-up. Both procedures achieved significant improvement in KOOS (62.0 to 24.4 in the TPOASI and 62.8 to 26.2 in the OW-HTO group, p < 0.001) and WOMAC score (68.9 to 24.1 in the TPOASI versus 69.9 to 26.1 in the OW-HTO group, p < 0.001). There were no significant differences in complications or femorotibial angle between the two groups but the only significant difference in the outcome parameters was the WOMAC stiffness score (19.6 in the TPOASI versus 26.5 in the OW-HTO group).

Conclusion: TPOASI achieves comparable results to OW-HTO in terms of clinical scores, radiographic results, and complications, but has the advantage of avoiding internal fixation removal.