Yutaka Nakamura

Prevention and early detection of venous thromboembolism (VTE) is important after arthroplasty of the lower limb. The purpose of this study was to investigate the associations between VTE and hemostatic markers after minimally invasive total knee arthroplasty (MIS-TKA). We performed a retrospective study of 50 patients (55 knees) who underwent primary unilateral MIS-TKA with periodic determination of D-dimer and soluble fibrin monomer complex (SFMC) concentrations and with ultrasonography. The development of symptomatic and asymptomatic VTE, location of deep venous thrombosis (DVT; proximal or distal), changes in SFMC and D-dimer concentrations, and correlations between hemostatic markers and VTE onset were evaluated. Twenty-six patients (47 %) had an asymptomatic distal DVT, but none had proximal DVT, pulmonary embolism, or symptomatic DVT. DVT was detected at postoperative day 1 (POD1) in 16 patients, POD3 in six, and POD5 in three (excluding detections of the same DVT in the same position on different days). DVT onset correlated significantly with SFMC concentration on POD1 and with D-dimer concentration on POD3. The D-dimer concentration did not differ significantly between patients who developed DVT (DVT+) and those who did not (DVT−) at each postoperative time. SFMC concentration differed between DVT+ and DVT− patients only on POD1. Analysis of each hemostatic marker classified as either within or outside the normal concentration range showed no significant correlations between D-dimer concentration and DVT onset at each period. There were significant correlations between SFMC concentrations and DVT onset on POD1 and POD3. There were also significant correlations between D-dimer positive (+) findings and/or SFMC+ findings and DVT onset on POD1 and POD3. D-dimer+ and/or SFMC+ findings had better specificity on POD1 and a positive predictive value on POD1 and POD3 compared with SFMC+ alone. SFMC concentration is an effective hemostatic marker for early detection of DVT. D-dimer concentration alone has limited value as a hemostatic marker for early detection of DVT. Measurement of both D-dimer and SFMC concentrations might be a more sensitive diagnostic tool than measuring SFMC concentration alone.

Effects of optional use of low-intensity pulsed ultrasound (LIPUS) treatments for delayed and non-union stress fractures at the anterior mid-tibia in athletes were examined. The subjects were 5 competitive athletes (4 males and 1 female) with the anterior mid-tibia stress fracture, which was confirmed by radiography and bone scintigraphy (Technetium-99m). All patients consistently received daily 20-minute LIPUS treatment, until radiographic recovery was achieved. Recovery was evaluated using clinical symptoms, radiographic examination, bone scintigraphy and functional outcome. Patients returned to full sports activity at an average of 3 months after the onset of treatment (range, 2 to 4 months). Absence of pain was achieved at an average of 3.8 months (range, 2 to 5 months), and disappearance of bone umbauzone was achieved at an average of 11 months (range, 8 to 14 months). These results were clearly faster than that of other previously reported conservative treatments. Thus, the LIPUS treatment is useful for early alleviation of focal pain in anterior mid-tibia stress fracture (delayed and nonunion stress fracture), resulting in early return to sports activity. However, achievement of pain-free status did not coincide with radiological indications of bone healing, thus careful follow-up should be necessary.