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This study assessed the reliability of the rapid exchange grip test for detecting submaximal grip effort, particularly evaluating its performance with motivated subjects with genuine hand weakness secondary to pain. Fifty normal participants performing with maximum effort then feigning hand weakness and 50 patients recovering from carpal tunnel surgery were studied. The results showed that the dynamic measure of grip strength equaled or exceeded the static measure in 28% of maximally performing participants (72% specificity), 58% of the carpal tunnel decompression patients (42% specificity), and 74% of participants giving submaximal grip effort (74% sensitivity). Sensitivities and specificities for other criteria of a positive test were also determined. Our findings suggest that the rapid exchange grip strength test cannot reliably detect voluntary submaximal effort.

Seventy-three thumbs in 67 women with osteoarthritis of the trapeziometacarpal joint were assessed prospectively. The patients were randomly allocated for treatment by either trapeziectomy alone (n = 26) or trapeziectomy with tendon interposition (n = 23) or ligament reconstruction (n = 24). A K-wire was passed through the thumb metacarpal base and across the trapezial space into the distal pole of the scaphoid in all procedures; this held the base of the metacarpal away from the scaphoid for 4 weeks. Standard thumb radiographs were used to calculate the trapezial space ratio before surgery and at 1-year follow-up examination. The trapezial space ratio decreased significantly from a preoperative mean of 0.40 (range, 0.20-0.56) to a mean of 0.18 (range, 0.08-0.30) after trapeziectomy, 0.16 (range, 0.07-0.30) after trapeziectomy with tendon interposition, and 0.20 (range, 0.00-0.33) after trapeziectomy with ligament reconstruction. There was no significant difference between these 1-year follow-up trapezial space ratios, suggesting that the placement of a K-wire across the trapezial void is as effective as tendon interposition or ligament reconstruction in creating a trapezial space in the short term at least. However, the need to create a trapezial space and maintain thumb length is questioned because the trapezial space height did not correlate with thumb strength at 1-year follow-up examination.

In vivo interstitial muscle pressures measured by wick catheter, tissue gas tensions measured by mass spectrometer, and glucose and high-energy phosphate metabolism measured fluorometrically were studied in the anterior tibial (AT) and vastus lateralis (VL) muscles of primate limbs during and following tourniquet ischemia (2.5 hours; 400 mm Hg) to elucidate postischemic edema and its metabolic consequences. During ischemia, interstitial pressure in the VL rose, while in the AT it decreased, but 24 hours later pressures in both experimental muscles were significantly greater than those in the controls. In both experimental muscles PO2 decreased significantly within 15 minutes of ischemia. PCO2 increased significantly in the AT at 30 minutes and at 75 minutes in the VL muscle. Twenty-four hours later only PO2 in the experimental AT was significantly different than its matched control. During ischemia glucose and phosphocreatine (CrP) decreased significantly, and G-6-P and lactate increased significantly in both muscles, but at 24 hours glucose levels were 25% lower and G-6-P 16.2% higher in the experimental AT and CrP 34% lower in the experimental VL. This study shows that there are significant acute and delayed alterations in primate muscle metabolism following tourniquet ischemia and suggests that these changes may be related to the anatomic location of the muscle studied and the type of trauma it has sustained.

Tourniquet ischemia results in tissue hypoxia which has been measured indirectly by blood gas analysis. The Medspect mass spectrometer allows direct measurement of gas tension in different tissues and may provide more useful information regarding safe tourniquet times. Calibrated Teflon catheters were inserted into the subcutaneous tissue (11 animals), tibial medullary cavities (bone) (nine animals), and tibialis anterior muscles (10 animals) in both lower extremities of anesthetized stumptail monkeys. Tourniquet ischemia was maintained for 1 hour at 400 mm Hg. Tissue and venous blood gas tensions were recorded from both limbs for 1 1/2 hours. Comparisons between gas tensions in each tissue group were made on the basis of their percentage change from control values. In the ischemic limb within 5 minutes muscle PO2 fell 42 +/- 4% (p is less than 0.001), whereas bone and subcutaneous PO2 dropped 25 +/- 4% (p is less than 0.05). Blood PO2 fell 29 +/- 3% and differed only from that of muscle (p is less than 0.01). One hour after tourniquet inflation, blood PO2 levels has fallen 90 +/- 5% (p is less than 0.001) from their control. Changes in tissue PCO2 were less dramatic and did not vary significantly from those recorded in venous blood. After deflation, blood PO2 exceeded its control by 20 +/- 6% (p is less than 0.005) in 5 minutes, but tissue tensions remained 50 +/- 6% below their control values. These studies indicate that tissue gas tensions are a more sensitive indicator of tourniquet hypoxia than are blood gases within the ischemic extremity.