Total knee arthroplasty after ipsilateral peripheral arterial bypass graft: acute arterial occlusion is a risk with or without tourniquet use.

A retrospective review was done of the total joint registry at the Mayo Clinic, Rochester, Minnesota, which contains the computerized records of 19,808 consecutive total knee arthroplasties (TKAs) including primary and revision that were performed from 1970 to 1997. From that database, 9 patients were found to have had a TKA after an ipsilateral peripheral arterial reconstruction. One patient had had bilateral peripheral arterial reconstruction followed by bilateral TKA, and 10 TKAs were reviewed. The medical records were reviewed retrospectively with particular attention given to the type of peripheral bypass surgery performed, the bypass graft source, the timing of the bypass surgery relative to TKA, the use of a tourniquet at the time of TKA, and the occurrence of complications after TKA. Of the 10 TKAs, 2 patients had acute arterial occlusion. One patient had a tourniquet, and the other patient did not. There was not a statistical correlation between graft type, tourniquet use, timing of surgery, postoperative anticoagulation, and occurrence of arterial occlusion. There is a marked risk of acute thrombosis of an ipsilateral arterial bypass graft after TKA that cannot be eliminated by performing the TKA without a tourniquet. Careful monitoring of the vascular status of the limb is required in the early postoperative period to detect arterial compromise. Should limb ischemia be suspected, an emergent vascular surgery consultation is required, and arterial flow to the lower extremity must be re-established.

Changes in stroke volume and maximal aerobic capacity with increased blood volume in men women.

This study determined whether the effects of acute plasma volume expansion (PVX) or 10 days of training on stroke volume during submaximal cycling and on treadmill maximal oxygen uptake (VO2max) were similar between men and women. Subjects performed a submaximal cycle test and a treadmill test to exhaustion under three conditions: control, PVX, and after training. Cycle peak VO2 (VO2peak) and blood volume were measured before and after training. Training consisted of daily 1-h bouts [30 min at 80% peak heart rate (HRpeak) and ten 2-min intervals at 95% HRpeak alternating with 1-min low-intensity pedaling] on a cycle ergometer for 10 consecutive days. Training increased cycle VO2peak in men [P < 0.05; 3.14 +/- 0.13 vs. 3.42 +/- 0.13 (SE) l/min] and women (2.11 +/- 0.10 vs. 2.37 +/- 0.12 l/min) and increased blood volume in men (67.6 +/- 3.0 vs. 72.3 +/- 3.1 ml/kg) and women (62.7 +/- 2.2 vs. 65.6 +/- 2.4 ml/kg). As a result of the greater blood volume with PVX and with training, stroke volume (ml) during submaximal cycling increased in men (control 110 +/- 4; PVX 123 +/- 4; trained 121 +/- 4) and women (control 87 +/- 5; PVX 95 +/- 6, trained 96 +/- 7). Treadmill VO2max (ml.kg-1.min-1) did not change with PVX despite a 6-7% reduction in hemoglobin concentration, whereas training resulted in an increase in VO2max in men (control 47.9 +/- 2.8; PVX 46.7 +/- 2.8; trained 49.9 +/- 2.6) and women (control 38.0 +/- 1.2; PVX 36.9 +/- 1.2; trained 39.2 +/- 1.2). The effects of PVX or training on stroke volume or VO2max did not differ between men and women. An additional finding was an increase in diastolic and mean blood pressures at 65% of cycle VO2peak with PVX and with training in women. Thus men and women hold similar cardiac reserve capacities for increasing stroke volume and, as a result, VO2max is maintained despite a reduction in hemoglobin concentration. However, gender differences in blood pressure regulation with increased blood volume might exist.

Strength training effects on rearfoot motion in running.

The investigation examined isokinetic (IK) and nonisokinetic (NIK) strength training programs for the inversion (INV) and eversion (EV) muscles on pronation during running. Seventy-seven volunteers were videotaped running on a treadmill at 3.8 m.s-1 and total pronation (delta beta PRO) was computed. Eighteen heel-strike runners with the largest values of delta beta PRO (X = 16.7 degrees) were selected as subjects. During the pre- and posttests, isokinetic muscle strength at 20 and 180 degrees.s-1 was determined for the concentric (CON) and eccentric (ECC) actions of the INV and EV muscle groups. The subjects also were videotaped running on a treadmill (3.8 m.s-1). The IK training group performed three sets of eight CON and ECC repetitions at 20, 90, and 180 degrees.s-1 for both muscle groups; and the NIK subjects did exercises commonly used in ankle rehabilitation. Each group trained three times weekly for 8 wk. The IK group showed significantly (P < or = 0.05) CON and ECC strength increases for all INV test conditions and three of the four EV conditions (20 degrees.s-1 CON and ECC, and 180 degrees.s-1 CON). They also demonstrated significant decreases in the rearfoot (2.2 degrees) and pronation/supination (2.9 degrees) angles at heel strike and in delta beta PRO (-2.2 degrees).l The NIK group exhibited no change in rearfoot motion and only increased INV strength at the 180 degrees.s-1 ECC test condition. The findings suggest that pronation can be decreased by an isokinetic strength training program for the INV and EV muscles.