Introduction and Aims: To study the natural history of the bone bruising of the knee and to identify the effect of weight-bearing and associated internal derangement on clinical improvement and radiological progress of the bone bruising of the knee.

Method: Patients with an acute knee injury were prospectively subjected to clinical and MRI examination within 48 hours of injury. Patients with osteoarthritis, bleeding disorder and previous injury or surgery to the injured knee were excluded. Internal derangement of the knee joint was identified. Patients with bone bruising (study group) were randomised into weight-bearing and non weight-bearing groups and followed-up for clinical and MRI examination at six weeks, three months, six months and 12 months. At follow-up, bone bruising on MRI was classified as Progressive, Static, Resolving or Resolved. Patients without bone bruising (control group) were similarly followed up for clinical examination. Lyshom score was used for clinical assessment.

Results: 28 patients were available for the follow-up. Average age was 24. There were eight patients in control group and 10 patients each in weight-bearing and non weight-bearing group. Eleven patients had associated internal derangement of the knee joint.

Clinical improvement was better in the control group compared to the study group. Patients with isolated bone bruising were doing better than those with associated internal derangement.

On radiological examination there was tendency for the bone bruise to progress in the first six weeks but majority started resolving by three months time. All isolated BB were resolved by six months, but there was delayed resolution of BB associated with ID.

Weight-bearing status did not influence clinical or radiological course of bone bruising.

Conclusion: Weight bearing does not alter the course of the bone bruising. Internal derangement associated with bone bruising delayed radiological resolution and clinical improvement of the patient.