High survival rates and patient satisfaction 12 years after medial open wedge HTO surgery: A prospective cohort study.

Purpose: Medial open wedge high tibial osteotomy (HTO) can delay knee arthroplasty (KA) in patients with medial compartment varus knee osteoarthritis (OA). However, prospectively collected long-term outcomes and survival rates are limited. The purpose of this study was to assess the survival rate and the outcome following HTO.

Methods: In this prospective cohort study with initially 120 knees from 112 patients treated from 2008 to 2011 with an HTO, 95 knees from 88 patients (age: 47.0 ± 7.6 years; female: n = 28) were followed-up. The minimum follow-up was 12 years or an earlier conversion to KA. The 5-, 10- and 12-year survival rates were calculated. The Lysholm and IKDC scores were assessed preoperatively and 1.5, 6 and 12 years postoperatively.

Results: At the last follow-up (12.9 ± 0.8 (12.0-15.1 years), 67.4% (n = 64) had no conversion to KA. 31 knees (32.6%; 2 unicompartmental KA, 29 total KA) were converted to a KA on average 7.3 ± 3.3 (1.5-13.0) years after the HTO. The 5-, 10- and 12-year survival rates were 88.2%, 76.3% and 69.7%. Knees without conversion to KA had significantly higher scores at the last follow-up compared to preoperatively: The Lysholm score increased from 60.4 ± 21.1 (14.0-91.0) preoperatively to 89.1 ± 12.5 (39.0-100.0), 86.5 ± 13.8 (39.0-100.0) and 82.6 ± 18.3 (30.0-100.0). The IKDC score also increased from 51.8 ± 16.6 (15.0-93.0) preoperatively to 77.7 ± 14.8 (21.0-100.0), 70.9 ± 15.3 (26.0-98.0) and 72.5 ± 18.1 (14.0-95.0) at the corresponding postoperative time points 1.5, 6 and 12-years.

Conclusion: HTO to treat varus medial OA showed good long-term outcomes. Most patients can expect no conversion to KA for more than twelve years and a higher subjective knee function than preoperatively.

Level of evidence: Level IV.