Repetitive activity alters perfusion of proximal interphalangeal joints ofthe human hand

Objective: To examine whether competitive volleyball players show any diffe rence in perfusion of their proximal interphalangeal (PIP) joints compared with a healthy group of subjects. Also to assess the viability of a dual wa velength laser Doppler imager (LDI) in making these measurements. Setting: Physiology laboratory. Participants: Ten active volleyball players who had experienced repetitive finger joint injury and 12 age- and sex-matched normal control subjects. Main Outcome Measures: Using a modified LDI incorporating a near- infrared (850 nm laser as well as a standard red (633 nm) laser, scans were performe d over the dorsum of the hands of the volleyball players and the control gr oup. Results: Higher perfusion values were obtained with the 850-nm laser than w ith the red 633-nm laser. When referenced to adjacent skin blood flow, perf usion over PIP joints of volleyball players was found to be significantly h igher than that in control subjects (p = 0.00012; n = 10-12). Conclusions: The higher perfusion values obtained using the 850-nm laser su ggest that the longer wavelength laser is measuring perfusion in a greater volume of tissue, which could include subcutaneous structures. Volleyball p layers have significantly higher perfusion over the PIP joints, which is un likely 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 Fur increased PIP perfusion is not clear; it may represent ongoing tissue inflammation due to repeated injury, or it could be an adaptive resp onse to the stresses placed on these joints by this type of repetitive acti vity. Clinical Relevance: Near-infrared laser Doppler imaging has the potential t o provide a noninvasive clinical assessment of finger joint injuries.