Table 1

Eligibility criteria

Dutch trial16Qatar trial17
Inclusion criteria

  • Age 18–50 years.

  • Clinical diagnosis of acute hamstring injury.

  • Initial MRI within 5 days of injury.

  • MRI-confirmed grade 1 or 2 hamstring lesion.

  • Age 18-50 years.

  • Acute onset of posterior thigh pain.

  • Initial MRI within 5 days of injury.

  • MRI-confirmed grade 1 or 2 hamstring lesion.

  • Gender: male.

  • Available to perform five sessions of physiotherapy a week at the clinic.

  • Available for follow-up.

Exclusion criteria

  • Contraindication for MRI.

  • Chronic hamstring injury.

  • Chronic low back pain.

  • Cause of injury is an extrinsic trauma.

  • Not capable of performing rehabilitation.

  • No intention to return to full sports activity.

  • Unwilling to receive intramuscular injections.

  • Previous injection therapy for this injury.

  • Contraindication for MRI.

  • Reinjury or chronic hamstring injury.

  • Concurrent injury inhibiting rehabilitation.

  • Unwilling to comply with follow-up.

  • Needle phobia.

  • Overlying skin infection.

  • Diabetes, immune-compromised state.

  • Medication increasing bleeding risk.

  • Medical contraindication to injection.