Summary

Long-term function of TKA following proximal tibial osteotomy (PTO) is excellent, with patients demonstrating comparable outcome scores and equivalent knee preference between TKA following PTO and contralateral knees which underwent index TKA without prior PTO.

Abstract

Introduction

Proximal tibial osteotomy (PTO) is a well-established extra-articular technique for the treatment of varus deformity and medial compartment osteoarthritis. However, the utility of non-arthroplasty interventions must be weighed against their potential effects on subsequent total knee arthroplasty (TKA). The purpose of this study was to robustly evaluate the long-term effect of PTO on subsequent TKA by employing paired outcomes in patients with bilateral TKAs following unilateral osteotomy.

Methods

All patients undergoing unilateral PTO performed between 1980 – 2007 with subsequent bilateral TKAs at a single institution were reviewed. Knee Society scores (KSS), Forgotten Joint Score 12 (FJS-12), subjective knee preference, and revision rates were compared between the PTO-TKA side and contralateral TKA-only side.

Results

We evaluated 140 TKAs performed in 70 patients (21 F, 39 M) who underwent unilateral PTO with subsequent conversion to bilateral primary TKA (16 simultaneous, 54 staged). Mean age at the time of PTO was 50 ± 7 years, with patients converting to TKA at a mean of 14 ± 7 years following ipsilateral PTO. Patients were 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 post-TKA improvements in KSS (p < 0.001), with no significant difference in scores at 2 years of follow-up when comparing their knees in a pairwise fashion (p = 0.38). Revision rates were similar (p = 0.76), with 5 PTO-TKA knees (7%) and 4 control TKA-only knees (6%) undergoing revision at a mean of 5 years postoperatively.

At the time of final follow-up, PTO-TKA knees demonstrated similar KSS (75 ± 6) and FJS-12 scores (72 ± 26) compared to the contralateral TKA-only side (KSS: 69 ± 13, p = 0.09; FJS-12: 70 ± 28, p = 0.73). When queried, 19% of patients preferred their PTO-TKA knee, 19% preferred the contralateral knee, and 63% stated their knees were equivalent. Tegner activity score at final follow-up was 2.5 ± 1.4.

Conclusion

PTO demonstrates satisfactory durability, with a mean of 14 years between PTO and conversion to TKA. Long-term function of TKA following PTO is excellent, with patients demonstrating comparable outcome scores and equivalent knee preference between PTO-TKA and TKA-only knees.