MRI-Demonstrated Outcome of Subchondral Stress Fractures of the Knee After Treatment with Iloprost or Tramadol: Observations in 14 Patients

Abstract

Objective: 

To investigate the outcome of subchondral stress fractures (SSF) of the knee after treatment with the prostacyclin analogue Iloprost or the opioid analgesic Tramadol.

Design: 

Case series/retrospective review.

Setting: 

Tertiary care center.

Patients: 

Fourteen patients with at least a single subchondral stress fracture of the knee, surrounded by bone marrow edema, visible on T1-weighted and short tau inversion recovery magnetic resonance images.

Interventions: 

Nine patients had been treated with oral Iloprost (group 1; 11 SSF) and 5 patients with Tramadol (group 2; 5 SSF) for 4 weeks in the course of a double-blind, randomized clinical trial. MR images were obtained at baseline (1 day before the start of treatment), after 3 months, and after 1 year.

Main Outcome Variables: 

SSF volumes and their rates of change between baseline and follow-up examinations, as determined on T1-weighted images by computer-assisted quantification.

Results: 

After three months, the SSF volumes had decreased by a median of 42.2% in group 1 and increased by a median of 2.2% in group 2 (P = 0.008). After 1 year, the median decrease in SSF volumes was 100.0% in group 1 and 65.7% in group 2 (P = 0.017).

Conclusion: 

This small case series suggests that healing of SSF is more pronounced after Iloprost treatment.