Measurement of the rate of fracture healing is a major problem in fracture research. Bone mineral density (BMD) of fracture callus has been used as a measure of healing in diaphyseal fractures. However, metaphyseal fractures (especially in the elderly) are now the commonest type of fracture and are a significant public health problem. This study investigated whether measurement of BMD at the fracture site in the distal radius can be used as a measure of fracture healing.

We recruited 28 patients who had sustained a dorsally displaced distal radial fracture which was deemed to require treatment by intrafocal wire fixation. All patients had acceptable correction of dorsal and radial angle at final x ray (3 months). Wrist function was measured using the Patient Rated Wrist Evaluation (PRWE – a validated outcome measure for use after distal radial fractures), grip strength,and range of motion. All measurements were made at 6, 12 and 26 weeks. BMD was measured at the fracture site (examining the BMD of the medullary bone at the fracture site after removal of wires), in the opposite wrist and the lumbar spine using QCT at 6 weeks after fracture.

There was no correlation between fracture site BMD and BMD at the other wrist or the lumbar spine (r < 0.3). The BMD at the fracture site was higher than the BMD at the other wrist (mean 168 vs 70 HU; p< 0.001 paired T test). There was no relationship between fracture site BMD or the ratio of BMDs fracture site / normal wrist, and any of the functional assessments (proportion grip strength recovered, range of motion or PRWE (r < 0.3)).

15 of these patients underwent a second QCT at 12 weeks after fracture. There was no significant change in fracture site BMD between the first and second scan.

These data indicate that fracture site BMD is unlikely to be a useful method of measuring metaphyseal bone healing. The increase in BMD at the fracture site was unexpected; possible explanations include impaction of bone or high BMD in woven bone (the relationship of which to bone stiffness is uncertain).

Older fracture patients frequently ask whether their osteoporosis will affect fracture healing. There is only limited previous data about this. We investigated recovery after distal radial fracture, and compared it with BMD of the other distal radius and the lumbar spine (measured using quantitative CT).

All 28 patients had sustained a dorsally displaced distal radial fracture which was deemed to require treatment by intrafocal wire fixation. All patients had acceptable correction of dorsal and radial angle at final x ray (3 months). Wrist function was measured using the Patient Rated Wrist Evaluation (PRWE – a validated outcome measure for use after distal radial fractures), grip strength,and range of motion. All measurements were made at 6, 12 and 26 weeks. BMD was measured in the opposite wrist and the lumbar spine using QCT at 6 weeks after fracture.

There was no correlation between recovery of grip strength (% of contralateral grip strength) at 6,12,or 26 weeks with BMD at either site. Similarly, there was no correlation between BMD and either absolute PRWE scores at any time point or improvement in PRWE between time points. The strongest predictor of recovery of grip appeared to be the proportion of grip recovered at 6 weeks (correlation between% grip recovered at 6 weeks and 3 months r = 0.85; at 6 weeks and 6 months r= 0.56; both p < 0.001). This was not affected by age or variations in measured final dorsal or radial angles or length within this group. It was not affected by degree of preoperative fracture displacement.

These data suggest that recovery of function after distal radial fractures is not influenced by osteoporosis. The data about the importance of initial recovery of grip suggest that factors other than bone position and bone healing may affect rate of functional recovery after distal radial fracture.