Repetitive activity alters perfusion of proximal interphalangeal joints of the human hand

To examine whether competitive volleyball players show any difference in perfusion of their proximal interphalangeal (PIP) joints compared with a healthy group of subjects. Also to assess the viability of a dual wavelength laser Doppler imager (LDI) in making these measurements.

Physiology laboratory.

Ten active volleyball players who had experienced repetitive finger joint injury and 12 age- and sex-matched normal control subjects.

Using a modified LDI incorporating a near- infrared (850 nm) laser as well as a standard red (633 nm) laser, scans were performed over the dorsum of the hands of the volleyball players and the control group.

Higher perfusion values were obtained with the 850-nm laser than with the red 633-nm laser. When referenced to adjacent skin blood flow, perfusion over PIP joints of volleyball players was found to be significantly higher than that in control subjects (p=0.00012; n=10-12).

The higher perfusion values obtained using the 850-nm laser suggest that the longer wavelength laser is measuring perfusion in a greater volume of tissue, which could include subcutaneous structures. Volleyball players have significantly higher perfusion over the PIP joints, which is unlikely to be due to differences in skin perfusion over the two regions but is more likely to be related to hyperemia of the underlying PIP joints. The reason for increased PIP perfusion is not clear; it may represent ongoing tissue inflammation due to repeated injury, or it could be an adaptive response to the stresses placed on these joints by this type of repetitive activity.

Near-infrared laser Doppler imaging has the potential to provide a noninvasive clinical assessment of finger joint injuries.