Unicompartmental knee arthroplasty for spontaneous osteonecrosis of the medial tibial plateau.

BACKGROUND

There have been very few reports on isolated medial tibial plateau osteonecrosis, and the condition has not been clearly described. Unicompartmental knee arthroplasty (UKA) may be an appropriate treatment method for this condition. The aims of this study were to report our experience of using mobile-bearing knee implants for osteonecrosis of the medial tibial plateau and to discuss the etiology and treatment of this type of osteonecrosis.

METHODS

This study included six consecutive patients with isolated medial tibial plateau osteonecrosis treated with an Oxford mobile-bearing knee implant. The average age was 71.0 years. We preoperatively graded the tibial necrosis lesion using radiographic findings. We also assessed the area and size of necrosis, extent of the surrounding high-density area, and the presence of any meniscal lesions by preoperative magnetic resonance imaging (MRI), and pre- and postoperative Oxford Knee Scores (OKS) were evaluated.

RESULTS

MRI findings revealed that all patients had meniscal lesions in addition to a necrotic lesion. All patients significantly improved in their OKS. No knees required revision for either infection or loosening.

CONCLUSIONS

The etiology of these cases of necrosis is still unclear, but the current study suggested an association with medial meniscal lesions. The results of the study were promising, showing a good short-term clinical outcome of Oxford mobile-bearing UKA for this type of osteonecrosis.