Potential of employing a quantum iterative reconstruction algorithm for ultra-high-resolution photon-counting detector CT of the hip.

INTRODUCTION: This study investigated the image quality of a new quantum iterative reconstruction algorithm (QIR) for high resolution photon-counting CT of the hip. METHODS: Using a first-generation photon-counting CT scanner, five cadaveric specimens were examined with ultra-high-resolution protocols matched for radiation dose. Images were post-processed with a sharp convolution kernel and five different strength levels of iterative reconstruction (QIR 0 - QIR 4). Subjective image quality was rated independently by three radiologists on a five-point scale. Intraclass correlation coefficients (ICC) were computed for assessing interrater agreement. Objective image quality was evaluated by means of contrast-to-noise-ratios (CNR) in bone and muscle tissue. RESULTS: For osseous tissue, subjective image quality was rated best for QIR 2 reformatting (median 5 [interquartile range 5-5]). Contrarily, for soft tissue, QIR 4 received the highest ratings among compared strength levels (3 [3-4]). Both ICCbone (0.805; 95% confidence interval 0.711-0.877; p < 0.001) and ICCmuscle (0.885; 0.824-0.929; p < 0.001) suggested good interrater agreement. CNR in bone and muscle tissue increased with ascending strength levels of iterative reconstruction with the highest results recorded for QIR 4 (CNRbone 29.43 ± 2.61; CNRmuscle 8.09 ± 0.77) and lowest results without QIR (CNRbone 3.90 ± 0.29; CNRmuscle 1.07 ± 0.07) (all p < 0.001). CONCLUSION: Reconstructing photon-counting CT data with an intermediate QIR strength level appears optimal for assessment of osseous tissue, whereas soft tissue analysis benefitted from applying the highest strength level available. IMPLICATIONS FOR PRACTICE: Quantum iterative reconstruction technique can enhance image quality by significantly reducing noise and improving CNR in ultra-high resolution CT imaging of the hip.

Metal artefact reduction in low-dose computed tomography: Benefits of tin prefiltration versus postprocessing of dual-energy datasets over conventional CT imaging.

INTRODUCTION: The purpose of this study was to determine the potential for metal artefact reduction in low-dose multidetector CT as these pose a frequent challenge in clinical routine. Investigations focused on whether spectral shaping via tin prefiltration, virtual monoenergetic imaging or virtual blend imaging (VBI) offers superior image quality in comparison with conventional CT imaging. METHODS: Using a third-generation dual-source CT scanner, two cadaveric specimens with different metal implants (dental, cervical spine, hip, knee) were examined with acquisition protocols matched for radiation dose with regards to tube voltage and current. In order to allow for precise comparison, and due to the relatively short scan lengths, automatic tube current modulation was disabled. Specifically, the following scan protocals were examined: conventional CT protocols (100/120 kVp), tin prefiltration (Sn 100/Sn 150 kVp), VBI and virtual monoenergetic imaging (VME 100/120/150 keV). Mean attenuation and image noise were measured in hyperdense and hypodense artefacts, in artefact-impaired and artefact-free soft tissue. Subjective image quality was rated independently by three radiologists. RESULTS: Objectively, Sn 150 kVp allowed for the best reduction of hyperdense streak artefacts (p < 0.001), while VME 150 keV and Sn 150 kVp protocols facilitated equally good reduction of hypodense artefacts (p = 0.173). Artefact-impaired soft tissue attenuation was lowest in Sn 150 kVp protocols (p ≤ 0.011), whereas all VME showed significantly less image noise compared to conventional or tin-filtered protocols (p ≤ 0.001). Subjective assessment favoured Sn 150 kVp regarding hyperdense streak artefacts and delineation of cortical bone (p ≤ 0.005). The intraclass correlation coefficient was 0.776 (95% confidence interval: 0.712-0.831; p < 0.001) indicating good interrater reliability. CONCLUSION: In the presence of metal implants in our cadaveric study, tin prefiltration with 150 kVp offers superior artefact reduction for low-dose CT imaging of osseous tissue compared with virtual monoenergetic images of dual-energy datasets. The delineation of cortical boundaries seems to benefit particularly from spectral shaping. IMPLICATIONS FOR PRACTICE: Low-dose CT imaging of osseous tissue in combination with tin prefiltration allows for superior metal artefact reduction when compared to virtual monoenergetic images of dual-energy datasets. Employing this technique ought to be considered in daily routine when metal implants are present within the scan volume as findings suggest it allows for radiation dose reduction and facilitates diagnosis relevant to further treatment.

[Reversed total shoulder arthroplasty in rotator cuff defect arthropathy]. / Inverse Schultertotalendprothese bei Rotatorenmanschettendefektarthropathie.

BACKGROUND: In a progredient rotator cuff tear with tendon retraction, fatty infiltration and atrophy of rotator cuff muscles the humerus cannot be centered and stabilized sufficiently in the glenohumeral joint. This leads to rotator cuff defect arthropathy as an eccentric osteoarthritis with acetabularization and wear of the acromion, as well as of the glenoid. INDICATION: A painful pseudoparalysis of the shoulder indicates the implantation of a reversed total shoulder arthroplasty (rTSA) to reduce pain and restore active motion. The rTSA improves the motoric function of the deltoid muscle by medialization and caudalization of the center of rotation via an optimized lever arm and is also indicated in cranio-caudally centered osteoarthritis with static posterior humeral decentration due to a bi-concavely eroded glenoid. THERAPY: Currently, humeral anatomical resection with an inclination of 135° and a humeral retrotorsion of 20-40°, in rTSA in contrast to 155° inclination, has been shown to lead to better glenohumeral motion without loss of stability. Additionally, a reduced glenohumeral offset should be restored by especially bony lateral augmentation of the glenoid. In a pre-operatively positive lag sign for external rotation caused by a rupture of the infraspinatus/teres minor tendon, a lateral latissimus/teres major muscle tendon transfer in rTSA can optimize active external rotation. The tendon of the subscapularis muscle should be re-fixated in the deltopectoral approach for rTSA whenever possible for better anterior stability of the glenohumeral joint. Larger diameters of the glenospheres have been shown to have more stability and better motion. Humeral metaphyseal metal liners with corresponding polyethylene glenospheres can avoid osteolysis of the inferior scapular neck caused by polyethylene debris due to impingement of the humeral liner at the scapular neck.

[Surgical approach to the shoulder. Lesser tuberosity osteotomy]. / Operativer Zugang zum Schultergelenk: Die Tuberculum-minus-Osteotomie.

Osteotomy of the lesser tuberosity for the surgical delto-pectoral approach to the glenohumeral joint results in good visualization and overview and sufficient anatomical refixation of the insertion of the subscapularis muscle. However, clinical and biomechanical studies have not shown clearly significantly better results for osteotomy concerning ultimate load to failure, displacement after cyclic loading and outcome in patients compared with tenotomy and tenodesis of the subscapularis tendon. One advantage of osteotomy, however, is the potential radiological evaluation of the refixation with healing of the bony fragment. In the context of refixation, securing of the sutures behind the stem during implantation can be beneficial because it prevents sutures cutting through the bone. This benefit is increased in cemented stems by means of better suture fixation. With respect to the choice of osteotomy or tenotomy, the bony substance and tendon quality of the insertion of the subscapularis muscle should be evaluated.

[Arthroscopically assisted reduction of acute acromioclavicular joint separations: comparison of clinical and radiological results of single versus double TightRope™ technique]. / Die arthroskopisch unterstützte Stabilisierung der akuten AC-Gelenksprengung: Vergleich der klinischen und radiologischen Ergebnisse der Single- vs. Double-TightRope™-Technik.

BACKGROUND: The aim of this study was to compare the results of the single (STR) versus double TightRope™ (DTR) technique for stabilisation of acute separations of the AC joint with the hypothesis that DTR achieves lower CC distance. PATIENTS AND METHODS: A total of 29 consecutive patients treated operatively with the TR technique (mean age 38.1 years, n=26 male) were analysed in a cohort study with a mean follow-up of 13.3 months (12.0-21.7). Acute AC joint separations types III and V according to Rockwood (R) were included; R types I, II, IV and VI were excluded. The prospective scores determined pre-op and 3, 6 and 12 months post-op and X-rays were evaluated. RESULTS: Of the patients 12 suffered an R type III and 17 an R V separation; 14 were treated with STR and 15 with DTR. With STR, 8 R III and 6 R V injuries and with DTR 4 R III and 11 R V injuries were treated arthroscopically. STR achieved an increased CC distance >125% compared to the contralateral AC joint in five cases (36%). Two of them occurred as R V and three as R III injury. DTR achieved a CC distance >125% in two cases of an R V injury (13%). CONCLUSION: The DTR technique provides lower CC distance compared to the STR technique, without a significant difference of CC distance and scores.

[Suicide in old age: the underestimated risk. An analysis of 1,894 patients in the Trauma Registry of the German Trauma Society]. / Suizid im Alter - das unterschätzte Risiko. Eine Untersuchung an 1.894 Patienten des Traumaregisters der DGU.

BACKGROUND: In Germany, the number of suicides and suicide attempts (n = 9,616) exceeds the number of traffic deaths (n = 4,152) by far. It is unknown how many suicide attempts are treated in trauma centres. Due to a lack of registered suicide attempts in Germany, no data exist about injury patterns, mortality or duration of treatment. MATERIALS AND METHODS: We prospectively analysed data collected on emergency room patients from the Trauma Registry of the German Trauma Society (TR-DGU) between 1993 and 2009. All patients with an Injury Severity Score (ISS) ≥ 9, age ≥ 18 years and a documented suicide attempt were included in the study. The main target points were epidemiological data, cause of injury and injury patterns, ISS, gender distribution, mortality, duration of treatment and patients' psychiatric medical history. RESULTS: Of 42,248 patients of the TR-DGU, 1,894 were included in the study; 274 patients were ≥ 65 years old. The most common method was jumping from a height among the group of female patients, whereas the use of firearms predominated in the male group. The average ISS was 31 points in all patient groups. The mortality was highest in patients aged ≥ 65 years. Psychiatric disorders were found predominantly in women. CONCLUSION: Of all severely injured patients in trauma centres, 5% suffered their injuries as a consequence of a suicidal attempt. In women who survived initially, jumping from a height was the most frequently chosen method. In elderly men the use of firearms dominated. The significant increase of mortality in elderly patients, preexisting depressive conditions and the expected increase in the number of these patients as a consequence of the changed age pyramid should lead to more intensive recognition and treatment of this disease and possibly improved suicide prevention.

[Current treatment options for complete ruptures of the pectoralis major tendon]. / Die zeitgemäße Therapie der kompletten Ruptur des M. pectoralis major.

The rupture of the pectoralis major tendon is an uncommon pathological condition that is reported in literature to prevail among athletes, although also case reports and case series of nursing home residents or workers can be found, as well as traumatic lesions. Among athletes, pectoralis major tendon ruptures have shown a significant increase in incidence over the last years. This may be due to the higher number of individuals taking part in high-impact sports and weight-lifting. In the recent literature, there are only few recommendations to rely on conservative treatment alone. Especially in athletes, numerous case reports and series give the recommendation for an early surgical intervention. Comparing the results of the two treatment plans, there is some evidence for a superior outcome after surgical repair with better cosmesis, better functional results, better recovery of muscle power and return to sports compared to the conservative treatment. In summary, anatomic surgical repair is the treatment of choice for complete acute ruptures of the pectoralis major tendon or muscle in athletes. In all other cases, especially in the elderly, conservative treatment remains an important option.

Increased glenohumeral translation and biceps load after SLAP lesions with potential influence on glenohumeral chondral lesions: a biomechanical study on human cadavers.

PURPOSE: The aim of the study was to evaluate the stabilizing function of the long head of biceps tendon (LHB) and its tension, both without and with the presence of SLAP lesion to analyze a potentially occurring humeral chondral print of LHB with consecutive glenohumeral chondral lesions in SLAP lesions. METHODS: Testings were performed on 21 fresh frozen human cadaver shoulders with intact shoulder girdle by a 5 axis industrial robot with a force/moment sensor and 20 N joint compression, 50 N force in anterior, posterior, anterosuperior, and anteroinferior direction, and 0°, 30°, 60° of abduction. LHB was connected over a force measuring sensor with 5 N and 25 N preload. A type IIC SLAP lesion was created arthroscopically. RESULTS: A significant increase in anterior and anteroinferior translation was evaluated, whereas the LHB tension increased significantly in at most anterior and anterosuperior direction. The highest increase in translation and LHB tension after SLAP lesion was measured in anterior translation in at most 60° of abduction. The glenohumeral translation was significantly higher in SLAP lesions without LHB tenotomy than after isolated LHB tenotomy. CONCLUSIONS: SLAP lesions lead to increased glenohumeral translation and concurrently LHB tension and load in at most anterior direction. The increased anterior glenohumeral instability and the increased LHB load pressing on the humeral head might cause glenohumeral chondral lesions with a typical chondral print-like lesion on the humeral head underneath the LHB.

[Incidence and mechanism of injuries in cable-wakeboarding: a prospective study]. / Verletzungsarten und Verletzungshäufigkeiten beim Cable-Wakeboard: eine prospektive saisonbegleitende Studie.

UNLABELLED: Cable-wakeboarding has become more and more popular in the last years in Germany and worldwide as well. The mechanism, frequency and severity of injuries is still unclear and not described in the literature yet. Thus to compare the injuries of cable-wakeboarding with similar sports we decided to perform this prospective study during a six months summer season. The study included 122 actives with a mean age of 25 years (15 - 42, +/- 5.876), 81,1 % male, sending an online questionnaire to us every month. 98 % of the participants suffered 277 injuries during 8647 hours of activity, 108 (39 % 12 / 1000 h) had to be treated medically. We found out most frequently mild injuries (61 % 19.5 / 1000 h), 15 % very severe injuries (4.8 / 1000 h), 14 % severe injuries (4.5 / 1000 h) and 10 % medium-severe injuries (3.2 / 1000 h). Injuries of the knee and the shoulder dominated in more than 20 % each with more than 70 % distorsions and contusions. CONCLUSION: Cable-wakeboarding is not more dangerous in regard to injuries than similar trendy sports even though the rate of mild injuries not treated medically is quite higher.

Osteochondral autologous transplantation for the treatment of full-thickness cartilage defects of the shoulder: results at nine years.

We describe the outcome at a mean follow-up of 8.75 years (7.6 to 9.8) of seven patients who had undergone osteochondral autologous transplantation for full-thickness cartilage defects of the shoulder between 1998 and 2000. These patients have been described previously at a mean of 32.6 months when eight were included. One patient has been lost to follow-up. The outcome was assessed by the Constant shoulder score and the Lysholm knee score to assess any donor-site morbidity. Standard radiographs and MR scores were obtained and compared with the pre-operative findings and the results from the previous review. No patient required any further surgery on the shoulder. The mean Constant score improved significantly until the final follow-up (p = 0.018). The Lysholm score remained excellent throughout. There was a significant progression of osteoarthritic changes from the initial surgery to the first and final follow-up but this did not appear to be related to the size of the defect, the number of cylinders required or the Constant score (p = 0.016). MRI showed that all except one patient had a congruent joint surface at the defect with full bony integration of all osteochondral cylinders. The results have remained satisfactory over a longer period with very good objective and subjective findings.