Instabilities and Osteoarthritis of the Sternoclavicular Joint. / Instabilitäten und Arthrose des Sternoklavikulargelenks.

Injury to the sternoclavicular joint (SCG) is very rare, accounting for 3% of shoulder injuries and < 1% of instabilities. Consequently, both the treatment of acute instabilities and their subsequent states (chronic instabilities/SCG arthrosis) are controversial. While treatment has so far been mostly conservative, in recent years there has been a trend towards surgical therapy.Considerable violence, such as that found in traffic accidents or contact sports, can tear the extremely stable ligaments between the medial clavicle and sternum. While anterior dislocation is easier to reduce in most cases, instability remains in up to 50% of cases. In most cases, posterior instability requires rapid reduction, particularly due to the anatomical proximity to important cardio-pulmonary structures. If this succeeds, the rate of persistent instabilities is low. For chronic instability, reconstruction/augmentation of the ligament apparatus with tendon grafts in the "Figure of 8 configuration" has proven to be the standard technique in recent years.

Dynamic locking screws in proximal humeral plate osteosynthesis demonstrate superior fixation properties: a biomechanical study.

PURPOSE: Angular stable implants reduced the complication rate in the treatment of humeral head fractures. But the failure rate is still high. To further reduce the risk of cut-out, cement augmentation of screws was introduced. A reason for failure of plate osteosynthesis might be the extremely high stiffness of the screw-plate interface leading to a loss of reduction and cut-out of screws. A more homogeneous distribution of the forces on all screws may avoid secondary dislocation. We hypothesize that dynamic osteosynthesis minimizes screw loosening and results in a higher load to failure than standard locking screws. METHODS: Twelve paired human humerus specimens were analysed. A standardized three-part fracture model with a metaphyseal defect was simulated. Within each pair of humeri, one was fixed with a Philos plate and standard locking screws (LS), whereas the other humerus was fixed with a Philos plate and dynamic locking screws (DLS). A cyclic varus-bending test or a rotation test with increasing loading force was performed until failure of the screw-bone-fixation. RESULTS: In the varus bending test, pairs failed by screw loosening in the humeral head. The LS-group reached 2901 (601-5201) load cycles until failure, while the DLS-group failed after 3731 (2001-5601) cycles. This corresponds to a median loading of 195 N for the LS-group and 235 N for the DLS-group (p = 0.028). In the rotation test the LS-group reached a median of 1101 (501-1501) load cycles until failure of fixation occurred, while the DLS-group failed after 1401 (401-2201) cycles (p = 0.225). CONCLUSIONS: Plate fixation using dynamic locking screws for the treatment of proximal humerus fractures demonstrated more load cycles until failure compared to standard locking plate osteosynthesis.

Influence of Sutures on Cartilage Integrity: Do Meniscus Sutures Harm Cartilage? An Experimental Animal Study.

PURPOSE: To evaluate whether different suture materials in meniscal repair may harm cartilage. METHODS: A preloaded linear friction testing setup including porcine knees with porcine cartilage, porcine meniscus, and different suture materials (braided nonabsorbable, absorbable monofilament) was used. Five groups with different tribological pairs were tested: cartilage on meniscus (control), cartilage on cartilage (control No. 2), and cartilage on different meniscus sutures (3 groups). Cartilage integrity was analyzed macroscopically by the India ink method and histologically using Giemsa-eosin-stained undecalcified methyl methacrylate sections. Cartilage lesions were classified by using a quantitative scoring system. RESULTS: The control groups did not show cartilage damage, either macroscopically or histologically. Loading cartilage with sutured menisci led to significant damage of the superficial radial and transitional zones with braided nonabsorbable (P = .03) and absorbable monofilament (P = .02) sutures at final examination. Menisci sutured with braided nonabsorbable material resulted in deeper damage to the cartilage. However, there were no significant differences between the suture materials. Sutures oriented perpendicular to surface motion led to a larger defect than parallel-oriented sutures. CONCLUSIONS: Braided nonabsorbable and absorbable monofilament suture materials cause significant damage to cartilage during long-term cyclic loading in vitro. The extent of damage depends on suture orientation. CLINICAL RELEVANCE: This study provides data on the extent to which different suture materials in meniscus repair may harm cartilage.

Intramedullary Cortical Button Repair for Distal Biceps Tendon Rupture: A Single-Center Experience.

PURPOSE: The aim of this retrospective study was to evaluate the clinical outcome and complication rate of intramedullary cortical button repair for distal biceps tendon rupture (partial and complete tears). METHODS: Between 2010 and 2014, a total of 28 patients with an acute distal biceps tendon rupture underwent intramedullary cortical button repair. Twenty-four patients (mean age, 49 years) with a mean follow-up of 28 months were included in the study. Twenty patients were examined clinically and by maximum isometric strength testing in flexion (at 90°) and supination of both arms. Twenty-four patients completed functional scores including the Mayo Elbow Performance Score (MEPS), the Andrews-Carson-Score (ACS) and the shortened Disabilities of the Arm, Shoulder, and Hand (QuickDASH) questionnaire. Furthermore, follow-up radiographs of 24 patients were analyzed. RESULTS: Compared with the contralateral elbow, the active range of motion (ROM) was the same. The mean strength for flexion was 100.8% ± 14% and for supination 93.1% ± 22% compared with the uninjured side. The mean MEPS for all patients was 95.6 ± 8.2, the mean ACS 194.2 ± 9.4 and the QuickDASH 3.8 ± 7.6. Heterotopic ossification (HO) was seen on radiographs in 46% of patients, but was symptomatic in only 1 patient. One patient suffered a tendon rerupture, and 1 asymptomatic button migration was seen in the follow-up. CONCLUSIONS: Intramedullary cortical button repair provides good results with respect to strength, ROM, and functional outcomes. Because the posterior cortex is not violated, the risk of iatrogenic posterior interosseous nerve injury is minimized. However, the patient should be warned of a high prevalence of postoperative HO. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

The influence of radio frequency ablation on intra-articular fluid temperature in the ankle joint - a cadaver study.

BACKGROUND: Radio frequency ablation devices have found a widespread application in arthroscopic surgery. However, recent publications report about elevated temperatures, which may cause damage to the capsular tissue and especially to chondrocytes. The purpose of this study was the investigation of the maximum temperatures that occur in the ankle joint with the use of a commercially available radio frequency ablation device. METHODS: Six formalin-fixed cadaver ankle specimens were used for this study. The radio frequency device was applied for 120 s to remove tissue. Intra-articular temperatures were logged every second for 120 s at a distance of 3, 5 and 10 mm from the tip of the radio frequency device. The irrigation fluid flow was controlled by setting the inflow pressure to 10 mmHg, 25 mmHg, 50 mmHg and 100 mmHg, respectively. The controller unit voltage setting was set to 1, 5 and 9. RESULTS: Maximum temperatures exceeding 50 °C/122 °F were observed for all combinations of parameters, except for those with a pressure of 100 mmHg pressure. The main critical variable is the pressure setting, which is highly significant. The controller unit voltage setting showed no effect on the temperature measurements. The highest temperature was 102.7 °C/215.6 °F measured for an irrigation flow of 10 mmHg. The shortest time span to exceed 50 °C/122 °F was 3 s. CONCLUSION: In order to avoid temperatures exceeding 50 °C/122 °F in the use of radio frequency devices in arthroscopic surgeries of the ankle joint, it is recommended to use a high irrigation flow by setting the pressure difference across the ankle joint as high as feasible. Even short intervals of a low irrigation flow may lead to critical temperatures above 50 °C/122 °F. LEVEL OF EVIDENCE: Level II, diagnostic study.

Using an anatomically preshaped low-profile locking plate system leads to reliable results in comminuted radial head fractures.

INTRODUCTION: For comminuted and displaced fractures of the radial head open reduction and internal fixation (ORIF) is recommended nowadays as the treatment of choice. Due to the development of locking plates the possibilities of ORIF in complex fracture types were extended. The purpose of this retrospective survey therefore was to review the preliminary subjective and objective results in patients treated by anatomically preshaped locked plating. A reliable fracture healing for these recently introduced plating devices was hypothesized. MATERIALS AND METHODS: Subjective and objective criteria included patient's satisfaction, pain rating on a visual analogue scale (VAS) and active range of motion (ROM) compared to the contralateral armside. Functional scoring included the Morrey elbow performance score (MEPS), the QuickDASH and the elbow self-assessment score (ESAS). Furthermore, follow-up radiographs were reviewed. RESULTS: Between 2011 and 2014 a total of 24 patients were managed with ORIF using anatomically preshaped low-profile locking plates. All patients had suffered from comminuted radial head fractures (type III-IV according to Mason classification). Twenty of 24 patients returned for follow-up examination after a mean of 30 months (range 18-53 months). Patients' satisfaction was rated as highly satisfied in 17 cases and satisfied in 3 cases. An unrestricted ROM for extension-flexion arc and pronation-supination arc was rated in 10 cases. Minor ROM deficiencies with a 5° limited extension compared to the contralateral side was evaluated in 6 cases. Only four patients were rated with and extension and supination deficiency of 10°, one of whom with an additional pronation deficiency of 10°. The calculated MEPS was Ø 98 ± 4 (range 85-100), and the QuickDASH was Ø 3 ± 6 (range 0-21). The ESAS was completed by 18 patients with a mean of Ø 96.54 ± 2.95 (range 94-100) indicating a non-restricted elbow function. CONCLUSIONS: The treatment of comminuted radial head fractures using anatomically preshaped locking radial head plates represents a reliable and safe surgical approach, leading to good to excellent functional results. Being aware of the importance of the radial head for elbow stability, open reduction and internal fixation should be preferred prior to radial head resection or replacement in complex radial head fractures. Further trials with a higher number of patients are needed to confirm the advantages of preshaped radial head plates.

Return to sports after plate fixation of humeral head fractures 65 cases with minimum 24-month follow-up.

BACKGROUND: Humeral head fractures requiring surgical intervention are severe injuries, which might affect the return to sports and daily activities. We hypothesize that athletic patients will be constrained regarding their sporting activities after surgically treated humeral head fractures. Despite a long rehabilitation program physical activities will change and an avoidance of overhead activities will be noticed. METHODS: Case series with 65 Patients, with a minimum follow-up of 24 months participated in this study. All patients were treated using a locking plate fixation. Their sporting activity was investigated at the time of the injury and re-investigated after an average of 3.83 years. The questionnaire setup included the evaluation of shoulder function, sporting activities, intensity, sport level and frequency evaluation. Level of evidence IV. RESULTS: At the time of injury 61 Patients (94%) were engaged in recreational sporting activities. The number of sporting activities declined from 26 to 23 at the follow-up examination. There was also a decline in sports frequency and duration of sports activities. CONCLUSION: The majority of patients remains active in their recreational sporting activity at a comparable duration and frequency both pre- and postoperatively. Nevertheless, shoulder centered sport activities including golf, water skiing and martial arts declined or were given up.

TGF-ß1 impairs mechanosensation of human osteoblasts via HDAC6-mediated shortening and distortion of primary cilia.

Transforming growth factor ß (TGF-ß) is a critical regulator of bone density owing to its multiple effects on cell growth and differentiation. Recently, we have shown that TGF-ß1 effectively blocks bone morphogenetic protein (BMP) induced maturation of osteoblasts by upregulating histone deacetylase (HDAC) activity. The current study aimed at investigating the effect of rhTGF-ß1 treatment on the expression of specific HDACs and their cellular effects, e.g., microtubule structures (primary cilia) and mechanosensation. Exposure to TGF-ß1 most significantly induced expression of HDAC6 both on gene and protein level. Being most abundant in the cytoplasm HDAC6 effectively deacetylates microtubule structures. Thus, TGF-ß1-induced expression of HDAC6 led to deformation and shortening of primary cilia as well as to reduced numbers of ciliated cells. Primary cilia are described to sense mechanical stimuli. Thus, fluid flow was applied to the cells, which stimulated osteoblast function (AP activity and matrix mineralization). Compromised primary cilia in TGF-ß1-treated cells were associated with reduced osteogenic function, despite exposure to fluid flow conditions. Chemical inhibition of HDAC6 with Tubacin restored primary cilium structure and length. These cells showed improved osteogenic function especially under fluid flow conditions. Summarizing our results, TGF-ß1 impairs human osteoblast maturation partially via HDAC6-mediated distortion and/or shortening of primary cilia. This knowledge opens up new treatment options for trauma patients with chronically elevated TGF-ß1-levels (e.g., diabetics), which frequently suffer from delayed fracture healing despite adequate mechanical stimulation. KEY MESSAGES: Exposure to TGF-ß1 induces expression of HDAC6 in human osteoblasts. TGF-ß1 exposed human osteoblasts show less and distorted primary cilia. TGF-ß1 exposed human osteoblasts are less sensitive towards mechanical stimulation. Mechanosensation can be recovered by HDAC6 inhibitor Tubacin in human osteoblasts.

Concomitant intra-articular glenohumeral injuries in displaced fractures of the lateral clavicle.

PURPOSE: To detect concomitant intra-articular glenohumeral injuries, in acute displaced fractures of the lateral clavicle, initially missed due to unfeasible clinical evaluation of the acutely injured shoulder. METHODS: All patients suffering from an acute displaced lateral clavicle fracture with indication to surgical treatment underwent diagnostic shoulder arthroscopy prior to open reduction and internal fixation. In case of therapy-relevant intra-articular glenohumeral injuries, subsequent surgical treatment was performed. RESULTS: Intra-articular injuries were found in 13 of 28 patients (46.4 %) with initially suspected isolated lateral clavicle fracture. Additional surgical treatment was performed in 8 of 28 cases (28.6 %). Superior labral anterior-posterior (SLAP) lesions were observed in 4 of 28 patients (14.3 %; SLAP II a: 1; II b: 1; III: 1; and IV: 1). Lesions of the pulley system were found in 3 of 28 patients (10.7 %; Habermeyer III°). One partial articular supraspinatus tendon avulsion lesion (3.6 %) and one lesion of the subscapularis tendon (3.6 %; Fox and Romeo II°) were observed. CONCLUSIONS: Traumatic concomitant glenohumeral injuries in lateral clavicle fractures seem to be more frequent than expected in general. Subsequent surgical treatment of these formerly missed but therapy-relevant injuries may increase functional outcome and reduce complication rate. LEVEL OF EVIDENCE: IV.

The Elbow Self-Assessment Score (ESAS): development and validation of a new patient-reported outcome measurement tool for elbow disorders.

PURPOSE: To develop and validate an elbow self-assessment score considering subjective as well as objective parameters. METHODS: Each scale of the American Shoulder and Elbow Surgeons-Elbow Score, the Broberg and Morrey rating system (BMS), the Patient-Rated Elbow Evaluation (PREE) Questionnaire, the Mayo Elbow Performance Score (MEPS), the Oxford Elbow Score (OES) and the Quick Disabilities of the Arm, Shoulder and Hand (Quick-DASH) was analysed, and after matching of the general topics, the dedicated items underwent a fusion to the final ESAS's item and a score containing 22 items was created. In a prospective clinical study, validity, reliability and responsiveness in physically active patients with traumatic as well as degenerative elbow disorders were evaluated. RESULTS: Validation study included 103 patients (48 women, 55 men; mean age 43 years). A high test-retest reliability was found with intraclass correlation coefficients of at least 0.71. Construct validity and responsiveness were confirmed by correlation coefficients of -0.80 to -0.84 and 0.72-0.84 (p <0.05). Correlation coefficients of the ESAS and well-established elbow rating systems BMS, PREE, MEPS, OES and Quick-DASH were between 0.70 and 0.90 (p < 0.05). CONCLUSIONS: With this novel Elbow Self-Assessment Score (ESAS), a valid and reliable instrument for a qualitative self-assessment of subjective and objective parameters (e.g. range of motion) of the elbow joint is demonstrated. Quantitative measurement of elbow function may not longer be limited to specific elbow disorders or patient groups. The ESAS seems to allow for a broad application in clinical research studying elbow patients and may facilitate the comparison of treatment results in elbow disorders. The treatment efficacy can be easily evaluated, and treatment concepts could be reviewed and revised. LEVEL OF EVIDENCE: Diagnostic study, Level III.

Balloon-guided inflation osteoplasty in the treatment of Hill-Sachs lesions of the humeral head: case report of a new technique.

BACKGROUND: The use of the extra-vertebral balloon osteoplasty is increasing and in the meanwhile it has become a safe surgical technique in the treatment of tibial head, distal radius and calcaneus fractures. In addition, we already could show in a biomechanical setup that the balloon osteoplasty might be a safe tool for reduction in the treatment of Hill-Sachs lesions, but clinical application has not been performed so far. CASE PRESENTATION: We report the case of a 53 year- old male patient who was referred to our Trauma department (level I trauma center) after the first manifestation of a posterior shoulder dislocation due to an epileptic seizure, originated in a- up to this date unknown -glioblastoma. After closed reduction of the dislocated shoulder the X-ray showed a subcapital fracture of the proximal humerus with a large reversed Hill-Sachs lesion. We performed an open surgery via a deltoideopectoral approach and balloon osteoplasty was used to reduce the impression fracture (Hill-Sachs lesion) before fixing the fracture with a locking plate. In the post-operative CT scan we could show an anatomical reduction of the Hill-Sachs lesion. At the follow-up examination one year after surgery the patient reached full range of motion and stated no re-dislocation of the shoulder nor instability or pain. CONCLUSION: The reduction of an impressed humeral head fracture by use of balloon osteoplasty is a safe technique. This technique could be a new option in the treatment of Hill-Sachs lesions and might be an alternative to well known standard procedures like the remplissage or tendon transfers without affecting rotation.

Visualization of stress fractures of the foot using PET-MRI: a feasibility study.

BACKGROUND: Diagnosis and treatment of stress fractures still remains to be a clinical and radiological challenge. Therapeutic options vary from conservative treatment to surgical treatment without a clear treatment concept. Recently the combination of PET and MRI has been introduced, aiming a superior diagnostic accuracy in clinical practice. Therefore the aim of our study was to analyse whether PET-MRI would be a feasible technique to recognize stress fractures of the foot and to analyse if our conservative treatment plan leads to a good clinical outcome. METHODS: Therefore, 20 patients with suspected stress fractures of the foot and ankle underwent plain radiography and (18)F-Fluoride PET-MRI. Two blinded readers assessed in consensus both imaging techniques for the presence of stress fracture, stress reaction or osteoarthritis. Patients with stress fractures or stress reactions in the foot and ankle area underwent our conservative treatment plan, with immobilization in a VACO®ped cast for 6 weeks under partial weight bearing on forearm crutches. The benefit of our conservative therapeutic concept was evaluated by the patients on the basis of VAS and FAOS scoring systems before and after treatment. RESULTS: 8 out of 20 patients underwent conservative treatment after diagnosis of either a stress fracture or a stress reaction of the foot and ankle area. PET-MRI identified four stress fractures and seven stress reactions. In all cases, no pathological findings were present on plain X-ray. FAOS and VAS significantly improved according to the patients' records. CONCLUSIONS: PET-MRI seems to be a useful modality to diagnose stress fractures and stress reactions of the foot and ankle area, especially when conventional modalities, such as plain radiographs fail. Conservative management is a promising therapeutic option for the treatment of stress fractures. To rule out the benefits compared to a surgical treatment plan, further studies are needed.

Pronator quadratus repair after volar plating of distal radius fractures or not? Results of a prospective randomized trial.

BACKGROUND: The purpose of the present study was to investigate the influence of the pronator quadratus (PQ) muscle repair following volar plate fixation of distal radius fractures with special regards to the forearm pronation strength. During the early recovery period of 3 months, an improvement of pronation strength and functional scorings was hypothesized for the PQ repair when compared to no repair. METHODS: The inclusion criteria were (1) men or women between 18 and 80 years, (2) isolated, closed fractures of the distal radius, (3) A2 to B2 types of fracture according to the AO fracture classification system, (4) primary volar locking plate osteosynthesis. Patients were randomized to group A = PQ repair and group B = no repair. Follow-up examinations after 6 and 12 weeks included bilateral isometric pronation strength measurement, range of motion, the QuickDASH and the Mayo-Wrist-Score, and a visual analog scale (VAS). RESULTS: 60 patients (n = 31 in group A and n = 29 in group B) with an average age of 54 years (range 22-77 years) returned for both follow-up visits. The pronation strength measurements showed no significant differences between groups (PQ repair vs. no repair) neither at 6 weeks nor at 12 weeks. Additionally, no statistical significant differences were noted for ROM, QuickDASH-Score or Mayo-Wrist-Score. The VAS scoring revealed a significant decreased pain level after PQ repair at 6 weeks postoperatively (p = 0.017). CONCLUSION: An improved pronation strength after PQ repair in the early rehabilitation period could not be confirmed. However, the PQ repair might reduce pain in the early postoperative period. TRIAL REGISTRATION NUMBER: NCT02595229 (ClinicalTrials.gov, registered 02 November 2015).

Malpositioned olecranon fracture tension-band wiring results in proximal radioulnar synostosis.

BACKGROUND: Tension-band wiring (TBW) is a well-established fixation technique for two-part, transverse fracture types of the olecranon. However, complication rates up to 80 % are reported. By reporting on the enormous impact on the patient if failed the aim of the present report was to emphasize the importance of correct K wire positioning in TBW. CASE PRESENTATION: We present the case of a 49-year-old woman who suffered from a radioulnar synostosis of the forearm due to malpositioned K wires after TBW treatment. The patient was treated by heterotopic bone resection supported by ossification prophylaxis (radiotherapy and Indomethacin). At follow-up of 12 months after revision surgery, elbow motion was unrestricted with a strength grade 5/5. The patient was free of pain and reported no restrictions in daily as well as sporting activities. Radiologic assessment showed no recurrence of heterotopic bone tissue. CONCLUSION: Intraoperative radiographic and clinical examination of the elbow is highly recommended to identify incorrect hardware positioning and, therefore, to avoid serious postoperative complications in TBW.

Traumatic bilateral carotid artery dissection following severe blunt trauma: a case report on the difficulties in diagnosis and therapy of an often overlooked life-threatening injury.

BACKGROUND: Traumatic carotid artery dissections are very rare, often overlooked and life-threatening injuries. Diagnosis and treatment are difficult especially in multiple injured patients. CASE PRESENTATION: We report on a 28-year-old female major trauma patient (injury severity score, ISS 50) who was involved in a motor vehicle accident. She was primarily transferred to a level II trauma center. After initial assessment and operative management, an anisocoria was diagnosed on the intensive care unit. Subsequent CT angiography and extracranial duplex sonography revealed a bilateral internal carotid artery dissection. The patient was transferred to our level I trauma center where conservative treatment with high-dose heparin therapy was started at day two after trauma. Outcome after 6 months was very good. CONCLUSION: Besides presenting the case and outcome of this patient, the article discusses the diagnostic and therapeutic management of this extremely rare and often overlooked dangerous injury. To avoid overlooking carotid artery dissections, CT angiography of the neck region should be generously included into the initial multislice CT whole-body scan, when the injury results from an according trauma. For the best outcome, sites of hemorrhage should be abolished quickly and the anticoagulative therapy should be initiated as soon as possible. Interdisciplinary treatment of trauma surgeons and neurologists is crucial.

Growth factor release by vesicular phospholipid gels: in-vitro results and application for rotator cuff repair in a rat model.

BACKGROUND: Biological augmentation of rotator cuff repair is of growing interest to improve biomechanical properties and prevent re-tearing. But intraoperative single shot growth factor application appears not sufficient to provide healing support in the physiologic growth factor expression peaks. The purpose of this study was to establish a sustained release of granulocyte-colony stimulating factor (G-CSF) from injectable vesicular phospholipid gels (VPGs) in vitro and to examine biocompatibility and influence on histology and biomechanical behavior of G-CSF loaded VPGs in a chronic supraspinatus tear rat model. METHODS: G-CSF loaded VPGs were produced by dual asymmetric centrifugation. In vitro the integrity, stability and release rate were analyzed. In vivo supraspinatus tendons of 60 rats were detached and after 3 weeks a transosseous refixation with G-CSF loaded VPGs augmentation (n = 15; control, placebo, 1 and 10 µg G-CSF/d) was performed. 6 weeks postoperatively the healing site was analyzed histologically (n = 9; H&E by modified MOVIN score/Collagen I/III) and biomechanically (n = 6). RESULTS: In vitro testing revealed stable proteins after centrifugation and a continuous G-CSF release of up to 4 weeks. Placebo VPGs showed histologically no negative side effects on the healing process. Histologically in vivo testing demonstrated significant advantages for G-CSF 1 µg/d but not for G-CSF 10 µg/d in Collagen III content (p = 0.035) and a higher Collagen I/III ratio compared to the other groups. Biomechanically G-CSF 1 µg/d revealed a significant higher load to failure ratio (p = 0.020) compared to control but no significant differences in stiffness. CONCLUSIONS: By use of VPGs a continuous growth factor release could be obtained in vitro. The in vivo results demonstrate an improvement of immunohistology and biomechanical properties with a low dose G-CSF application via VPG. The VPG itself was well tolerated and had no negative influence on the healing behavior. Due to the favorable properties (highly adhesive, injectable, biocompatible) VPGs are a very interesting option for biologic augmentation. The study may serve as basis for further research in growth factor application models.

Evaluation of 18F-fluoride PET/MR and PET/CT in patients with foot pain of unclear cause.

UNLABELLED: Our objective was to compare the quality and diagnostic performance of (18)F-fluoride PET/MR imaging with that of (18)F-fluoride PET/CT imaging in patients with foot pain of unclear cause. METHODS: Twenty-two patients (9 men, 13 women; mean age, 48 ± 18 y; range, 20-78 y) were prospectively included in this study and underwent a single-injection dual-imaging protocol with (18)F-fluoride PET/CT and PET/MR. At a minimum, the PET/MR protocol included T1-weighted spin echo and proton-density fat-saturated sequences in 2 planes each with simultaneous acquisition of PET over 20 min. PET/CT included a native isotropic (0.6 mm) diagnostic CT scan (80 kV, 165 mAs) and a subsequent PET scan (2 min per bed position). By consensus, 2 masked interpreters randomly assessed both PET datasets for image quality (3-point scale) and for the presence of focal lesions with increased (18)F-fluoride uptake (maximum of 4 lesions). For each dataset (PET/CT vs. PET/MR), the diagnoses were defined using both PET and a morphologic dataset. Standardized uptake values (SUVs) from the 2 devices were compared using linear correlation and Bland-Altman plots. Moreover, we estimated the potential for dose reduction for PET/MR compared with PET/CT considering the longer acquisition time of PET/MR analyzing count rate statistics. RESULTS: Image quality was rated diagnostic for both PET datasets. However, with a mean rating of 3.0/3 for PET/MR and 2.3/3 for PET/CT, image quality was significantly superior for PET/MR (P < 0.0001). The sensitivity of the PET datasets in PET/MR and PET/CT was equivalent, with the same 42 lesions showing focal (18)F-fluoride uptake. In PET/MR, the mean SUVmean was 10.4 (range, 2.0-67.7) and the mean SUVmax was 15.6 (range, 2.9-94.1). In PET/CT, the corresponding mean SUVmean of PET/CT was 10.2 (range, 1.8-55.6) and the mean SUVmax was 16.3 (range, 2.5-117.5), resulting in a high linear correlation coefficient (r = 0.96, P < 0.0001, for SUVmean and for SUVmax). A final consensus interpretation revealed the most frequent main diagnoses to be osteoarthritis, stress fracture, and bone marrow edema. PET/CT was more precise in visualizing osteoarthritis, whereas PET/MR was more specific in nondegenerative pathologies because of the higher soft-tissue and bone marrow contrast. The longer acquisition time of MR compared with CT would potentially allow (18)F-fluoride dose reduction using hybrid (18)F-fluoride PET/MR imaging of at least 50% according to the counting rate analysis. CONCLUSION: In patients with foot pain of unclear cause, (18)F-fluoride PET/MR is technically feasible and is more robust in terms of image quality and SUV quantification than (18)F-fluoride PET/CT. In most patients, (18)F-fluoride PET/MR provided more diagnostic information at a higher diagnostic certainty than did PET/CT. Thus, PET/MR combines the high sensitivity of (18)F-fluoride PET to pinpoint areas with the dominant disease activity and the specificity of MR imaging for the final diagnosis with the potential for a substantial dose reduction compared with PET/CT.

Double intramedullary cortical button versus suture anchors for distal biceps tendon repair: a biomechanical comparison.

PURPOSE: The aim of this biomechanical in vitro study was to compare the novel technique of double intramedullary cortical button (DICB) fixation with the well-established method of suture anchor (SA) fixation for distal biceps tendon repair. METHODS: A matched-pair analysis (24 human cadaveric radii) was performed with respect to cyclic loadings and failure strengths. Twelve specimens per group were cyclically loaded for 1,000 cycles at 1.5 Hz from 5 to 50 N and from 5 to 100 N, respectively. The tendon-bone displacement was optically analysed using the Image J Software (National Institute of Health). Afterwards, all specimens were pulled to failure. Maximum load to failure and mode of failure were recorded. RESULTS: All DICB constructs passed the cyclic loading test, whereas 4 of the 12 specimens within the SA group failed by anchor pull-out. Cyclic loading showed a mean tendon-bone displacement of 0.6 ± 1.4 mm for the DICB group and 1.4 ± 1.4 mm for the SA group (n.s.) after 1,000 cycles with 50 N, and a mean displacement of 2.1 ± 2.4 mm for the DICB group and 3.5 ± 3.7 mm for the SA group (n.s.) after 1,000 cycles with 100 N. Load to failure testing showed a mean failure load of 312 ± 76 N and a stiffness of 67.1 ± 11.7 N/mm for the DICB technique. The mean load to failure for the SA repair was 200 ± 120 N (n.s.) and the stiffness was 55.9 ± 21.3 N/mm (n.s.). CONCLUSIONS: The novel technique of DICB fixation showed small tendon-bone displacement during cyclic testing and reliable fixation strength to the bone in load to failure. Moreover, all DICB constructs passed cyclic loadings without failure. Based on the current findings, a more aggressive postoperative rehabilitation may be allowed for the DICB repair in clinical use.

The functional outcome of forty-nine single-incision suture anchor repairs for distal biceps tendon ruptures at the elbow.

PURPOSE: The objective of this retrospective study was to evaluate the functional results of distal biceps tendon repair using suture anchors via a single-incision approach. METHODS: Forty-nine patients were re-examined at a mean follow-up of 44.2 ± 32.1 months (range, 12-119 months). Subjective and objective criteria included patient's satisfaction, active range of motion (ROM), maximum isometric strength in flexion (at 45° and 90°), and supination of both arms. Functional scoring included the Morrey elbow score (MES) and the QuickDASH. Furthermore, follow-up radiographs were performed. RESULTS: Eighty-six percent of patients were highly satisfied or satisfied with their outcome. Compared to contralateral, the active ROM of elbow flexion, extension, and pronation was not affected; however, supination was decreased by 3° (P < 0.001). The isometric maximum strengths showed significant deficits in all tested scenarios (at 45°, P = 0.002; at 90°, P < 0.001; for supination, P < 0.001). The MES and the QuickDASH were 97.2 ± 4.9 and 7.9 ± 13.9, respectively. Heterotopic ossifications (HO) were found in 39% of patients; however, with respect to scores and strength, no significant differences were seen compared to patients without HO. Moreover, four anchor failures were detected. CONCLUSIONS: Single-incision suture anchor repair provides high patient's satisfaction and good results with respect to ROM and functional scoring. Nevertheless, based on presented data, the patient has to be informed of postoperative HO and especially for supination strength weakness after surgery. Distal biceps tendon repair should be reserved for experienced upper extremity surgeons to avoid procedure-related complications.

Biomechanical comparison of menisci from different species and artificial constructs.

BACKGROUND: Loss of meniscal tissue is correlated with early osteoarthritis but few data exist regarding detailed biomechanical properties (e.g. viscoelastic behavior) of menisci in different species commonly used as animal models. The purpose of the current study was to biomechanically characterize bovine, ovine, and porcine menisci (each n = 6, midpart of the medial meniscus) and compare their properties to that of normal and degenerated human menisci (n = 6) and two commercially available artificial scaffolds (each n = 3). METHODS: Samples were tested in a cyclic, minimally constraint compression-relaxation test with a universal testing machine allowing the characterization of the viscoelastic properties including stiffness, residual force and relative sample compression. T-tests were used to compare the biomechanical parameters of all samples. Significance level was set at p < 0.05. RESULTS: Throughout cyclic testing stiffness, residual force and relative sample compression increased significantly (p < 0.05) in all tested meniscus samples. From the tested animal meniscus samples the ovine menisci showed the highest biomechanical similarity to human menisci in terms of stiffness (human: 8.54 N/mm ± 1.87, cycle 1; ovine: 11.24 N/mm ± 2.36, cycle 1, p = 0.0528), residual force (human: 2.99 N ± 0.63, cycle 1 vs. ovine 3.24 N ± 0.13, cycle 1, p = 0.364) and relative sample compression (human 19.92% ± 0.63, cycle 1 vs. 18.72% ± 1.84 in ovine samples at cycle 1, p = 0.162). The artificial constructs -as hypothesized- revealed statistically significant inferior biomechanical properties. CONCLUSIONS: For future research the use of ovine meniscus would be desirable showing the highest biomechanical similarities to human meniscus tissue. The significantly different biomechanical properties of the artificial scaffolds highlight the necessity of cellular ingrowth and formation of extracellular matrix to gain viscoelastic properties. As a consequence, a period of unloading (at least partial weight bearing) is necessary, until the remodeling process in the scaffold is sufficient to withstand forces during weight bearing.