Treatment of spontaneous osteonecrosis of the knee by daily teriparatide: A report of 3 cases

RATIONALE: Although the treatment of femoral head necrosis has already been established with the adoption of daily teriparatide, a clear consensus on the treatment of spontaneous osteonecrosis of the knee (SONK) has yet to be reached. Therefore, we focused on the treatment of SONK with daily teriparatide administration (20 μg, subcutaneous) and confirmed its effects to determine whether it is a valid option. PATIENTS’ CONCERNS: Three osteoporotic patients who were diagnosed with SONK complained of knee pain. DIAGNOSIS: SONK was diagnosed on magnetic resonance imaging in all cases. INTERVENTIONS: All patients took daily teriparatide as a treatment for SONK. OUTCOMES: There was a significant and dramatic reduction in the visual analog scale score 1 month after treatment. After 6 months of treatment, the sizes of the affected SONK lesions were smaller than in the initial phase, and plain X-rays showed no further signs of progression. LESSONS: Daily teriparatide might be an effective treatment for SONK.