Minimum 5-Year Outcomes of Osteochondral Autograft Transplantation with a Concomitant High Tibial Osteotomy for Spontaneous Osteonecrosis of the Knee with a Large Lesion

Objective The purpose of this study was to evaluate the mid-term clinical outcomes of osteochondral autograft transplantation (OAT) with concomitant high tibial osteotomy (HTO) in spontaneous osteonecrosis of the knee (SONK) with a large lesion. Design A total of 48 knees of 48 consecutive patients with SONK (lesion size >= 4 cm(2), no age criteria) who underwent opening wedge HTO and concomitant OAT were retrospectively investigated, and those who were followed up postoperatively for at least 5 years were included in this case series study. Clinical outcomes were evaluated using knee and function scores of Knee Society Score, radiographic outcomes were evaluated using the anatomical femorotibial angle (FTA), and these outcomes were compared between patients aged >= 70 years and Results Of the 48 cases, a total of 43 cases were available for review at a minimum of 5 years, and 5 cases were excluded from the analysis. Overall, the mean knee score improved from preoperative 48.8 +/- 13.3 to postoperative 87.9 +/- 8.6 at 1 year (P < 0.05) and 85.0 +/- 10.4 at final follow-up (P < 0.05 vs. preop., N.S. vs. 1 year). The mean function score also improved from preoperative 60.1 +/- 10.9 to postoperative 87.3 +/- 12.2 at 1 year (P < 0.05) and 84.2 +/- 12.4 at final follow-up (P < 0.05 vs. preop., N.S. vs. 1 year). The mean standing FTA was corrected significantly from 181.1 degrees +/- 2.7 degrees preoperatively to 169.7 degrees +/- 2.4 degrees at 1 year (P < 0.05) and 169.4 degrees +/- 3.1 degrees at final follow-up (P < 0.05 vs. preop., N.S. vs. 1 year). There were no significant differences in clinical and radiographic outcomes between patients aged >= 70 years and <70 years. There were 4 cases of lateral hinge fracture around the osteotomy site and 1 case of delayed union. None of the patients underwent revision surgery during the follow-up period (survival rate of 100%). Conclusions Mid-term clinical outcomes of patients with SONK who underwent HTO and OAT with a relatively large lesion were good.