Bone stress injuries.

Bone stress injuries are due to cyclical overuse of the bone. They are relatively common in athletes and military recruits but also among otherwise healthy people who have recently started new or intensive physical activity. Diagnosis of bone stress injuries is based on the patient's history of increased physical activity and on imaging findings. The general symptom of a bone stress injury is stress-related pain. Bone stress injuries are difficult to diagnose based only on a clinical examination because the clinical symptoms may vary depending on the phase of the pathophysiological spectrum in the bone stress injury. Imaging studies are needed to ensure an early and exact diagnosis, because if the diagnosis is not delayed most bone stress injuries heal well without complications.

MR imaging, bone scintigraphy, and radiography in bone stress injuries of the pelvis and the lower extremity.

PURPOSE: To compare MR imaging, radiography and bone scintigraphy in the diagnosis of stress injuries to bones of the pelvis and lower extremity. MATERIAL AND METHODS: Fifty consecutive conscripts with clinical signs of a stress injury to bone underwent MR imaging and bone scintigraphy. Forty-three patients also had radiographs available. Bone scintigraphy served as a gold standard. RESULTS: Compared to the bone scintigraphy, the sensitivity of radiography was 56%, specificity 94%, accuracy 67%, positive predictive value (PPV) 95%, and negative predictive value (NPV) 48%. The kappa value for radiography and bone scintigraphy was fair (0.39). Correspondingly, the sensitivity of MR imaging was 100%, specificity 86%, accuracy 95%, PPV 93% and NPV 100%. The kappa value for MR imaging and bone scintigraphy was very good (0.89). MR imaging depicted 3 bone stress injuries that were not visible on bone scintigraphy. Positive findings obtained from radiography correlated with MR signs of fracture line or callus (p<0.001). CONCLUSION: MR imaging is more sensitive than two-phase bone scintigraphy, and MR imaging should be used as the gold standard in the assessment of stress injuries of bone. Radiography reveals mainly the late phases of bone stress injuries, such as stress fracture and callus.

Dynamic contrast-enhanced MR imaging in symptomatic bone stress of the pelvis and the lower extremity.

PURPOSE: To assess the value of dynamic contrast-enhanced MR imaging in bone stress of the pelvis and the lower extremity. MATERIAL AND METHODS: Thirty patients (37 reactions; aged 17-25 years, mean 20.5 years) with MR findings of 37 bone stress reactions were examined using dynamic gadolinium contrast enhancement. The enhancement was evaluated with time-intensity curves. The highest slope and maximum enhancement values were calculated and compared with the different precontrast MR imaging signs of bone stress reactions. RESULTS: There was a significant difference in the highest slope values between the site of the bone stress reaction and the reference points. In 24 of the 37 reactions the dynamic contrast enhancement was regarded as positive. A fracture line, callus, and muscle edema were the MR imaging signs which had a significant correlation to the dynamic contrast enhancement. Neither periosteal nor marrow changes showed any significant correlation. A new MR grading system for bone stress reactions could be assessed. CONCLUSION: Increased tissue perfusion could be seen if precontrast MR imaging revealed callus, fracture line or muscle edema surrounding the bone stress reaction.

Electroencephalography and magnetic resonance imaging after diving and decompression incidents: a controlled study.

Electroencephalography and magnetic resonance imaging after diving and decompression incidents: a controlled study. Undersea Hyper Med 1999.; 26(2):61-65.--Diving incidents with symptoms of decompression sickness (DCS) and/or arterial gas emboli (AGE) might increase the degree of pathologic change in the electroencephalogram (EEG) or magnetic resonance imaging (MRI) of the supraspinal central nervous system (CNS). Diving itself, even without known symptoms of DCS and/or AGE, has been proposed to increase the number of CNS lesions using either EEG or MRI. In the first part of a two-part study we examined the effects of recompression treatment on EEG in decompression incidents in a group of sport and professional divers compared with a control group of healthy naval divers. In the second part we recorded brain MRI from three groups of volunteers: 1) divers who were treated for DCS in pressure chamber, 2) divers who had never had symptoms of DCS (and/or AGE), and 3) healthy normal controls who were not divers. Our results indicate that DCS increases the incidence of pathologic EEG recordings, whereas recompression treatment decreases them. The results of MRI do not verify evidence of increased numbers of CNS lesions in normal divers as compared to non-diving, healthy control subjects, whereas some of the divers treated for DCS in a pressure chamber had hyperintense lesions in brain white matter. None of them had any abnormalities in EEG, neurologic performance, or psychologic behavior. Both EEG and MRI are sensitive and non-specific methods for judging suspected evidence of brain lesions from diving or diving accidents.

Postoperative changes in blood flow in free muscle flaps: a prospective study.

We used color Doppler ultrasound (US) to study postoperative changes in blood flow in 10 non-innervated free latissimus dorsi (LD) muscle flaps transplanted onto lower extremities. The peak, mean, and minimum velocities, resistance index, and diameter of the pedicle, and the recipient and control arteries were recorded preoperatively and on the 2nd, 5th, and 10th days after surgery. In the pedicle of the transplant, the peak and mean velocities increased but not significantly during the follow-up. The minimum velocity value in the thoraco-dorsal artery was (mean+/-SD) 4+/-5 cm/sec preoperatively, and was in the leg 19+/-9 cm/sec (P < 0.05) on the 5th and 17+/-10 cm/sec (P < 0.05) on the 10th postoperative day. The preoperative value of the resistance index decreased from 0.92+/-0.12 to 0.79+/-0.08 on the 10th postoperative day (P < 0.05). In the recipient artery, the peak (117+/-37) and mean (35+/-16 cm/sec) velocities increased significantly on the 5th postoperative day compared to the preoperative value (79+/-22 and 14+/-6 cm/sec, respectively). The minimum velocity increased but not significantly. The resistance index was preoperatively 1.23+/-0.09 and 0.88+/-0.16 (P < 0.05) on the 10th postoperative day. This prospective clinical study demonstrates that blood flow in the pedicle and in the recipient artery of a free muscle flap increases after surgery. This phenomenon may be due to loss of vascular tone and decreased resistance after denervation. Increased blood flow helps to keep the microanastomosis open and also promotes wound healing.

Biodegradable and titanium plating in experimental craniotomies: a radiographic follow-up study.

Plain film radiography and computed tomography (CT) were evaluated in assessing the consolidation of experimental craniotomy lines covered with titanium miniplates or biodegradable self-reinforced poly-L-lactide (SR-PLLA) plates. Two sagittal (2.3-2.5 mm wide and 22 mm long) symmetrical craniotomy lines were made in the skulls of eight young sheep. One craniotomy line was covered with a biodegradable SR-PLLA plate and the other with a titanium miniplate. Both plates were fixed with four titanium miniscrews. Consolidation of the osteotomies was studied using plain film radiography and CT 6, 12, 20, and 52 weeks postoperatively. Microradiography and histology were used for reference. Plain film was not reliable in assessing osseous consolidation because false-positive results were obtained in three osteotomies. Osseous consolidation was more reliably assessed by CT, which showed consolidation on the SR-PLLA side within 20 weeks, whereas none of the titanium-plated lines was consolidated by 52 weeks. Superior consolidation under the resorbable plate was confirmed in histology and microradiography. The radiolucent SR-PLLA plates did not interfere with CT, whereas the titanium plates caused minor CT artifacts.

Blood flow in the lower limbs in the knee-chest position. Ultrasonographic study in unanaesthetised volunteers.

The knee-chest position for lumbar spine surgery is favoured because decreased filling of the epidural veins is associated with reduced peroperative bleeding. However, the position may be unfavourable from a circulatory point of view. In the present study, non-invasive assessment of circulation in the lower limbs was performed in 21 unanaesthetised, healthy volunteers who were placed in the surgical knee-chest position. Measurements included blood flow velocity (colour Doppler ultrasonography), oscillotonometric arterial blood pressure from upper and lower limbs and pulse oximetry from a toe. There was a statistically significant reduction in the posterior tibial artery flow velocity, maximally 31.6%, when the subject was moved from the prone to the knee-chest position. An enlargement of the trunk-femoral angle at the hip did not improve arterial flow. In 10 of the 21 volunteers, no flow in the posterior tibial vein was detected in the knee-chest position. In spite of the deteriorated blood flow, pulse oximetry indicated sufficient capillary flow in the very periphery of the lower limb. The change from prone to knee-chest position resulted in an increase in arterial blood pressure of the upper limb; the increase in diastolic arterial pressure was statistically significant (p < 0.001). It is concluded that the surgical knee-chest position involves deterioration of both the arterial and venous flow of the lower limbs. This should be considered in patients undergoing surgery in this position and, in particular, in those at risk of developing cardiovascular complications.

Postoperative MR imaging and ultrasonography of surgically repaired Achilles tendon ruptures.

PURPOSE: To evaluate and compare MR and US findings in an unselected group of patients with 1-3-year-old surgically repaired complete ruptures of the Achilles tendon. MATERIAL AND METHODS: Thirteen patients with complete Achilles tendon rupture underwent clinical, MR and US examinations. The average time interval from rupture to postoperative imaging was 18 months. RESULTS: The cross-sectional area of a postoperative tendon was 4.2 times that of the unaffected side. The shape of the operated tendon was more rounded than the unaffected side and it had irregular margins both in MR imaging and in US examination. In 4 of 13 cases an intratendinous area of intermediate to high signal intensity on proton density- and T2-weighted images was seen on MR. The size of this area varied from 4 to 18% of the cross-sectional tendon area. Two patients with the largest intratendinous area had poor clinical outcome. On US the tendon had mixed echogenicity in all cases and the tendon bands were thinner and shorter than normal. Comparison of dimension between MR and US revealed that in a.p. dimension the correlation was good (r = 0.87, p = 0.001), but in transversal width there was no significant correlation (r = 0.58, p = 0.06). CONCLUSION: The increased size and round irregular area of the operated Achilles tendon rupture was well detected by both MR and US, but intratendinous lesions were seen only by MR.

Sequelae in the abdominal wall after pedicled or free TRAM flap surgery.

Twenty-seven free transverse rectus abdominis musculocutaneous (TRAM) and 16 pedicled TRAM flap breast reconstruction patients were studied for 7 to 41 months (mean, 23 months) postoperatively to compare abdominal sequelae after these two operations. The patient groups were demographically similar; mean age was 47 years in both groups. Subjective grading of the results was similar in both groups. The incidence of minor lower abdominal bulges was higher (44%, 7/16) in the pedicled group than in the free TRAM flap group (4%, 1/27). No hernias were found. Delayed healing of the abdominal scar occurred in 3 free TRAM flap and 1 pedicled TRAM flap patients. Two free TRAM flap (8%) and 7 pedicled TRAM (44%) flap patients had minor edge necrosis of the breast. Trunk strength was tested using an isokinetic device (Lido Multi Joint II), and peak torque for flexion (mean, 111 Nm +/- 25 Nm in the free TRAM flap group and 123 Nm +/- 28 Nm in the pedicled TRAM flap group) and extension (mean, 144 Nm +/- 38 Nm and 167 Nm +/- 45 Nm) were measured. No statistical differences occurred between these groups. Sit-up performance was tested and graded from 1 to 6. Both groups performed equally (4.8 and 4.8) and within normal values for this age group. Ultrasonography of the rectus muscles revealed that in the free TRAM flap group, the rectus muscle of the operated side was significantly thinner (cranial segment 6.8 mm vs. 7.8 mm, p < 0.05), thus the harvesting of a segment of muscle below the umbilicus seems to disturb the quality of the entire muscle. The mean size of the muscular defect in the free TRAM flap group was 4.3 x 6.1 cm. In this study no differences in patient satisfaction or trunk strength could be found between free and pedicled TRAM flap patients.

Donor site morbidity of radial forearm flaps. A clinical and ultrasonographic evaluation.

Harvesting of a forearm flap based on the radial artery has been thought to cause functional or circulatory problems in the donor hand. Eighteen patients were examined three to 24 months after a radial forearm flap had been raised. The function of both hands was studied for grip strength, mobility of the wrist and elbow joints, and sensitivity of the area served by the superficial radial nerve. The patients were interviewed and the cosmetic result was evaluated. Duplex ultrasonography and colour Doppler ultrasonography of both ulnar arteries were done, and the brachial arteries were measured as controls. Angle-corrected peak flow velocity (cm/s) in the ulnar artery of the donor forearm was significantly increased at the level of the wrist compared with the control forearm (100.9 compared with 73.1 cm/s, p = 0.017), as was the ulnar: brachial peak flow velocity ratio (1.18 compared with 0.76, p = 0.001). The grip strength of the donor hand was weaker by 11.9% (86.5 compared with 72.2 Kp), 10 (56%) had areas of sensory loss over the radial nerve distribution, and seven of the 18 patients complained of cold intolerance. Four patients considered the donor site result so bad that they would not have chosen the operation had they known what the result would look like. The radial forearm flap donor site is not without problems, and the patients must be carefully selected and properly informed preoperatively.

Use of ultrasonography to evaluate muscle thickness and blood flow in free flaps.

The purpose of this study was to investigate the common belief that a microvascular transfer of a non-innervated free muscle flap loses muscle bulk over time. Sixteen patients (latissimus dorsi = 8, rectus abdominis = 7, and gracilis muscle = 1) were evaluated an average of 41 months after free flap transfer. Latissimus dorsi and lower extremity flaps displayed significantly more swelling than the other flaps. Flap bulk was measured by ultrasound. The mean thickness of upper extremity flaps was 10.3 +/- 1.8 mm (control muscles 11.8 +/- 2.8), lower-extremity 14.5 +/- 3.7 mm (control muscles 10.9 +/- 0.7), latissimus dorsi 14.3 +/- 2.2 mm (control muscles 10.3 +/- 0.8, P = 0.018), and rectus abdominis 11.2 +/- 1.2 mm (control muscles 12.4 +/- 1.9). Color Doppler ultrasonography was used to detect the pedicles of the free flaps and also to measure the peak velocity of blood flow intramuscularly and in the pedicles. In the upper extremities (n = 5) the pedicles could be found in only 20% of cases whereas in the lower extremities (n = 11) 91% of pedicles were located. (P = 0.013). Peak flow within the free flaps was significantly higher in the lower extremity (50% of the peak flow of the common femoral artery) than in the upper extremity (5% of the peak flow of the common femoral artery, P = 0.013). This study demonstrated that non-innervated free muscle flaps in the extremities maintain the original muscle thickness, although lower extremity and latissimus dorsi flaps have a trend to be thicker. Most pedicles of free muscle flaps in the upper extremities could not be located by ultrasound. However, flaps in the lower extremities most often have patent pedicles and also more vigorous intramuscular blood flow.

Ultrasonography and arthrography in the diagnosis of tears of the rotator cuff.

The accuracy of ultrasonography and arthrography in the prediction of lesions of the rotator cuff was evaluated and compared with the operative findings in a retrospective study of forty-nine patients (forty-nine shoulders). In the detection of full-thickness (stage-III) tears of the rotator cuff, ultrasonography had an over-all sensitivity of 74 per cent, a specificity of 95 per cent, an accuracy of 84 per cent, a predictive value of a positive test of 95 per cent, and a predictive value of a negative test of 75 per cent. In contrast, arthrography demonstrated a sensitivity of 93 per cent, a specificity of 95 per cent, an accuracy of 94 per cent, a predictive value of a positive test of 96 per cent, and a predictive value of a negative test of 91 per cent. Ultrasonography could not reliably differentiate between partial (stage-II) and full-thickness (stage-III) tears. Lesions of the long head of the biceps brachii tendon were recorded by ultrasonography for twenty-two patients (45 per cent) and by arthrography for eleven patients (22 per cent). The ultrasonographic finding of fluid in the sheath of this tendon is not a reliable sign of a lesion in the tendon.

Diagnostic performance of low field MRI in acute knee injuries.

The diagnostic performance of low field (0.1 T) magnetic resonance imaging (MRI) was studied prospectively and double-blindly among 33 patients with acute knee injuries. The subsequent arthroscopy was the golden standard. For lesions of the medial meniscus low field MR had a sensitivity of 88% and a specificity of 80%; for lesions of the lateral meniscus the sensitivity was 25% and the specificity 97%. For anterior cruciate ligament tears, low field MRI had a sensitivity of 83% and a specificity of 85%. The specificity for posterior cruciate ligament tears was 97%. The performance of low field MRI equalled that reported earlier for high field MRI, the only exception being the sensitivity for lateral meniscus lesions.

Bone malalignment in acute injuries of the wrist.

The purpose of this study was to analyze radiographic signs of carpal bone instability in patients with an acutely injured wrist. There were 80 patients (52 women and 28 men) with a fall on the outstretched hand. Fifty patients had a fracture of the distal radius, and eight had a scaphoid fracture. The patients with a bone fracture showed a larger scapholunate angle than those without a fracture (P less than 0.001, t-test). However, only four of them showed true carpal bone instability: two patients with a scaphoid fracture and one with a radius fracture had dorsiflexion instability of the wrist and one patient with a radius fracture had dorsal subluxation of the wrist. In addition, one patient without any bone fracture had scapholunate dissociation, one form of carpal bone instability. Although carpal bone instability is not frequent in an acutely injured wrist, its signs should be remembered in the radiographic analysis of the traumatic wrist to prevent subsequent articular disorders.

How many projections are really needed in angiographic assessment of the femoral bifurcation?

The purpose of this study was to analyze how many angiographic projections are needed in the diagnosis of hemodynamically significant stenoses of the femoral bifurcation. A total of 134 femoral bifurcations were examined with triplanar angiography in 67 patients (45 men and 22 women). The patients, ranging in age from 42 to 81 years (mean 63), suffered from incapacitating symptoms of peripheral arterial disease. The contralateral posterior oblique projection proved to be the most valuable in the assessment of hemodynamically significant arterial stenoses of the femoral bifurcation. An AP projection added information on stenoses of the inlets of the deep femoral artery in 9% of cases and on stenoses of the inlets of the superficial femoral artery in 6% of cases. An arteriographic examination should be started with a contralateral posterior oblique projection and this view will suffice in most cases.

Subacromial impingement decompressed with anterior acromioplasty.

Symptomatic (Stage II) impingement of the rotator cuff against the coracoacromial arch has been treated with anterior acromioplasty in 60 shoulders in 56 patients. Patient selection is crucial. Arthrography of the shoulder was routinely included in the preoperative diagnostic tools to rule out a tear of the rotator cuff. Since acromial shape may play a role producing a resistant impingement syndrome, special attention should be paid to patients with Type III of acromial inclination. The surgical procedure should include a thorough examination of the subacromial space as a whole, taking notice of all pathologic findings in the subacromial arch as well as in the underlying soft tissues. Restoring subacromial clearance, the patients were relieved of their symptoms. The result, rated according to the functional assessment of Neer, was excellent or satisfactory in 73%. Failure to recognize the associated bony as well as soft-tissue subacromial lesions was, however, a frequent cause of failure of surgical decompression operations.

Resistance of a defect of the supraspinatus tendon to intraarticular hydrodynamic pressure: an experimental study on rabbits.

The healing of a standardized defect of the supraspinatus tendon in a time-related series on rabbits was monitored with arthrography and simultaneous determination of the intra-articular hydrodynamic pressure of the glenohumeral joint. All normal glenohumeral joints produced a biphasic pressure versus volume curve. Rupture of a normal glenohumeral joint occurred at a pressure level of 140-170 mm Hg and was located in the area around the biceps tendon sheath. In joints with a defect of the supraspinatus tendon, leakage of the contrast medium was evident up to the sixth week, at an intra-articular pressure varying from 40 to 100 mm Hg. After week 6, no leakage of the cuff was seen during the determination of the intraarticular pressure. This was in accordance with the histological findings: the defect was covered with solid scar tissue from the ninth week onward. Resistance to hydrodynamic intraarticular pressure proved a reliable method of determining the strength of the healing of the supraspinal defects.

Wire-guided biopsies of nonpalpable breast lesions.

The purpose of this study was to review the results of mammographic wire-guided biopsies of nonpalpable breast lesions and the features of the lesions in the preoperative examinations. Sixty women, mean age 50.2 years (range 31 to 74), underwent a wire-guided biopsy of the lesion. Twenty-nine patients had preoperative fine needle aspiration of the lesion. The radiographic diagnosis was correct in 33 patients (55%); 25 had breast cancer and 8 patients had a benign lesion. In 9 of the 14 patients with clustered microcalcifications in mammography and in 13 of the 15 patients with a mass noted in mammography, the cytological examination was correct. Nonpalpable mammographic masses with regular borders and normal fine needle aspiration examination do not require biopsy. In malignant mammographic appearances associated with a normal fine needle aspiration examination, biopsy of the lesion should always be done.