2015 ISAKOS Biennial Congress ePoster #1519

The Comparative Analysis of Clinical Symptoms and MRI Findings After the Osteochondral Autograft Transfer for the Spontaneous Osteonecrosis of the Knee

Shogo Mukai, MD, Kyoto JAPAN
Yasuaki Nakagawa, MD, Kyoto, Kyoto JAPAN
Takahiko Saji, MD, Kyoto JAPAN
Hiromitsu Yabumoto, MD, Kyoto JAPAN
Eri Tarumi, MD, Kyoto JAPAN
Shigeru Yamada, MD, PhD, Kyoto , Kyoto JAPAN
Takashi Nakamura, MD, Kyoto JAPAN

National Hospital Organization Kyoto Medical Center, Kyoto, Kyoto, JAPAN

FDA Status Not Applicable

Summary: The clinical symptoms significantly improved by OAT on SONK patients, and the MRI findings of transferred plugs also improved, and the postoperative Lysholm score was significantly related with the preoperative Lysholm score , but not with MRI findings.




We treated spontaneous osteonecrosis of the knee(SONK) by osteochondral autograft transfer(OAT) because OAT can simultaneously reconstruct bone necrosis and surface cartilage injury. But there have been few reports about MRI findings of SONK after this joint preserving surgery. In this reports, we comparatively evaluated the clinical symptoms and MRI findings of SONK patients treated by OAT.

Materials And Methods

The materials were 22 SONK patients 23 knees( 5 male 5 knees and 17 female 18 knees), and the average age at the operation was 68.3 years old and average follow up period was 3.3 years. Clinical symptoms were evaluated by Lysholm score at the before and after the surgeries and MRI were taken at 1 year after the operation in all cases. The MRI evaluation criteria included 1)the incidence of recurrence of osteonecrosis,2) the degree of plug integration, 3)the degree of improvement of bone marrow edema. Statistical evaluations were made by non-parametric analysis.


There were no cases which need re-operation. The Lysholm score was 48.7 points before the operation and 88.3 points at the 1 year after the operation. All patients showed significant improvement, but the lower score before the operation correlated with the lower score after the operation.(R2=0.36) The postoperative scores showed the significant correlation with the lesion size(R2=0.32), not with age, sex, nor preoperative OA grade. MRI evaluation demonstrated 1) there were two(8%) very small cystic lesion occurred inside the plugs which was considered as recurrence of osteonecrosis, 2) the plug integration was good in 10 of 23 (44%) knees, 3) the bone marrow edema was restored in 19 of 23 (83%) knees.
The postoperative Lysholm scores were significantly related with the preoperative Lysholm scores(P=0.0006) and the lesion size(P=0. 0121), but were not related with the degree of plug integration nor the extent of the bone marrow edema.


The characteristic symptom of SONK is severe pain which is brought by bone necrosis itself or bone marrow edema. OAT can effectively treat the bone necrosis with subchondral bone defect and surface cartilage injury. But there is anxiety that surrounding bone marrow edema prevents transferred plugs from good integration. This report demonstrates that the low recurrence rate of osteonecrosis and the plug integration rate was not inferior to the results of younger patients previously reported, and that the improvement rate of bone marrow edema was high. The results also shows that the clinical results at 1 year after the OAT was good with OAT, and that the postoperative score was related with preoperative scores and with the lesion size but not with MRI findings such as the bone marrow edema or the plug integration.


The clinical symptoms significantly improved by the OAT in SONK patients, and the integration of transferred plugs and restoration of bone marrow edema were good, and the postoperative clinical results was significantly related with the preoperative clinical symptoms and the lesion size , but not with MRI findings.