Effect of impaired joint mobility on venous pump function of the healthy lower limb, a phelbodynamometric analysis

In this study, the effect of impaired knee or ankle-joint mobility on venou s muscle pump function of the lower limbs was investigated in 10 healthy yo ung subjects (5 males, 5 females, mean age: 25,5 +/- 3 years) by means of d irect venous blood pressure measurements under exercise conditions ("periph eral phlebodynamometry"). The subjects had to walk on a treadmill for 1 min ute on plain ground with a defined velocity (1.5 km/h). There were 3 experi mental conditions: walking with free joint mobility (1); walking with restr icted mobility of the knee (2), and the ankle joint (3). The primary outcom e measure was the venous pressure gradient between the resting and the mini mal pressure during exercise (Delta P-max), secondary outcome measures were the times to complete (T-0) and to half-maximal recovery (T-max1/2) of res ting venous pressure levels after exercise, respectively. As compared with condition 1 (free walking), reductions of knee (condition 2) and ankle-join t mobility (condition 3) resulted in significant decreases of Delta P-max ( p = 0.0323 and 0.0051, resp.; Wilcoxon signed rank test). This Delta P-max reduction was greater for walking with restricted ankle joint mobility than for walking with restricted knee joint mobility (21.5% versus 12.0%, p = 0 .045). By contrast, venous refilling times (T-0 and T-max1/2) were not infl uenced by restrictions of joint mobility. These results indicate that restr ictions of free joint mobility may result in ambulatory venous hypertension even in healthy young subjects. Therefore, in patients with preexisting ch ronic venous insufficiency impaired joint mobility may lead to additional f unctional deterioration and should be taken into account in both clinical p ractice and expert opinions.