Purpose

Proximal tibial osteotomy (PTO) is well-established for the treatment of coronal deformity and focal cartilage defects. However, the utility of joint preserving interventions must be weighed against potential effects on subsequent total knee arthroplasty (TKA). The purpose of this study was to determine the effect of PTO on subsequent TKA by robustly comparing outcomes in patients with bilateral TKAs following unilateral PTO.

Methods and Materials

Patients undergoing bilateral TKA between 2000–2015 at a single institution with previous unilateral valgus-producing PTO were reviewed. Knee Society Scores (KSS), Forgotten Joint Score 12 (FJS-12), subjective knee preference, and revision were compared between the PTO-TKA and contralateral TKA-only side.

Results

We evaluated 140 TKAs performed in 70 patients (24F, 46M) with unilateral PTO and subsequent bilateral TKA. Mean age at PTO was 50±8 years, with patients converting to TKA at a mean of 14±7 years following ipsilateral PTO and followed for a mean of 25±7 years (Range: 6–40).

PTOs demonstrated similar KSS (41±16) compared to their contralateral side (KSS: 39±16, p=0.67) immediately prior to arthroplasty. Patients had significant improvements in KSS (p<0.001) after TKA, with clinically similar KSS scores at 2–15 years of follow-up when comparing knees in a pairwise fashion (p>0.10). Five PTO-TKA knees (7%) and 4 control TKA-only knees (6%) underwent revision at a mean of 5 years postoperatively (p=0.76). A clinically relevant trend towards increased all-cause reoperation was observed in the PTO-TKA group (13% vs. 6%, p=0.24).

At final follow-up, PTO-TKA demonstrated similar FJS-12 scores (72±26) compared to the contralateral side (70±28, p=0.57). 19% of patients preferred their PTO-TKA knee, 19% preferred the contralateral knee, and 62% stated their knees were equivalent. Final Tegner activity score was 2.5±1.4.

Conclusion

Long-term clinical function of TKA following PTO is excellent, with comparable subjective outcomes and equivalent knee preference at 25 year follow-up compared to contralateral TKA-only knees.