Fig. 2. Proximal ascending colon, caecum and terminal Ileum lying with in the lesser sac.Fig. 3. Locule of gas with in the appendiceal lumen adjacent to the gastrooesophageal junction.

Measured activity ratios that fall within our normal range are likely to represent normal periprosthetic osteoblastic activity. Measured activity ratios that fall above the upper cut-offs of our normal range are likely to be abnormal. The cut-offs are robust in clinical practice and have utility in discriminating normal from abnormal stabilized arthroplasties where visual interpretation is ambiguous. Elevated AC/RA under 12 months and FC/RF under 24 months may represent normal periprosthetic activity and should be interpreted with caution.