Experimental guide wire placement for total shoulder arthroplasty in glenoid models: higher precision for patient-specific aiming guides compared to standard technique without learning curve.

BACKGROUND: Patient-specific aiming devices (PSAD) may improve precision and accuracy of glenoid component positioning in total shoulder arthroplasty, especially in degenerative glenoids. The aim of this study was to compare precision and accuracy of guide wire positioning into different glenoid models using a PSAD versus a standard guide. METHODS: Three experienced shoulder surgeons inserted 2.5 mm K-wires into polyurethane cast glenoid models of type Walch A, B and C (in total 180 models). Every surgeon placed guide wires into 10 glenoids of each type with a standard guide by DePuy Synthes in group (I) and with a PSAD in group (II). Deviation from planned version, inclination and entry point was measured, as well as investigation of a possible learning curve. RESULTS: Maximal deviation in version in B- and C-glenoids in (I) was 20.3° versus 4.8° in (II) (p < 0.001) and in inclination was 20.0° in (I) versus 3.7° in (II) (p < 0.001). For B-glenoid, more than 50% of the guide wires in (I) had a version deviation between 11.9° and 20.3° compared to ≤ 2.2° in (II) (p < 0.001). 50% of B- and C-glenoids in (I) showed a median inclination deviation of 4.6° (0.0°-20.0°; p < 0.001) versus 1.8° (0.0°-4.0°; p < 0.001) in (II). Deviation from the entry point was always less than 5.0 mm when using PSAD compared to a maximum of 7.7 mm with the standard guide and was most pronounced in type C (p < 0.001). CONCLUSION: PSAD enhance precision and accuracy of guide wire placement particularly for deformed B and C type glenoids compared to a standard guide in vitro. There was no learning curve for PSAD. However, findings of this study cannot be directly translated to the clinical reality and require further corroboration.

Tendon Repair Leads to better Long-Term Clinical Outcome than Debridement in Massive Rotator Cuff Tears.

INTRODUCTION: Massive tears in the rotator cuff are debilitating pathologies normally associated with loss of function and pain. Tendon reconstruction is seen as the standard treatment in order to preserve shoulder function and to inhibit cuff associated osteoarthritis. However, the effect on longer-term shoulder function and patient satisfaction is unknown. MATERIAL AND METHODS: 165 consecutive patients with massive tears were included. 57 debridement (mean age 61.9±8.7 years (range 43-77)) and 108 reconstruction (mean age 57.5±8.9 years (range 45-74)) cases could be followed up 2-4 (short-term), 5-6 (mid-term) and 8-10 (long-term) years after surgery. Evaluation was performed with the Constant, a modified ASES and the DASH score. Statistical analysis was done using Sigma-Stat Version 3.5 with a p-value<0.05 indicating statistical significant differences. RESULTS: All three scoring systems showed no significant differences in the short-term follow-up for the two groups (mean values: Constant debridement/repair: 70±11.9/66±13.6; ASES debridement/repair: 22.3±3.3/ 23.3±3.3; DASH debridement/repair: 22.3±11.0/ 24.3±10.1). In the mid-term (Constant debridement/repair: 51±2.9/68.3±5.2; ASES debridement/repair: 20.3±1.3/24.3±1.7; DASH debridement/repair: 31.0±6.5/20.3±5.4) and long-term follow-up (Constant debridement/repair: 42.3±3.8 /60.7±2.6, ASES debridement/repair: 17.3±0.5/21.7±0.5, DASH debridement/repair: 41.3±6.2/25.0±1.4), rotator cuff reconstruction revealed better objective results and better patients' satisfaction. CONCLUSION: Rotator cuff tendon repair leads to better long-term clinical outcome and subjective satisfaction compared to debridement. Tendon reconstruction should be considered as a treatment for patients suffering from massive rotator cuff tears, thus preserving shoulder function and by that means delay indication for reverse arthroplasty.

Resurfacing of the humeral head: An analysis of the bone stock and osseous integration under the implant.

Cementless-surface-replacement-arthroplasty (CSRA) of the shoulder aims for functional joint restoration with minimal bone loss. Good clinical results have been reported, but due to the radiopaque metal shell no data is available on the structure, osseous integration, and bone stock under the implant. 14 hemi-CSRAs (4 manufacturers) with two geometries (crown [n = 7]/ stem [n = 7] fixation) were retrieved from patients undergoing revision due to glenoidal erosion. Histological sections cutting through the implant centre and bone were analysed. Quantitative histomorphometry evaluated the bone-implant-contact and compared the bone-area to native humeral retrievals (n = 7). The bone-implant-interface was further assessed by scanning-electron-microscopy (SEM) and energy-dispersive-x-ray (EDX). Qualitative histology revealed a reduced and inhomogeneous bone stock. Obvious signs of stress shielding were observed with bone predominantly visible at the stem and implant rim. Quantitative histomorphometry confirmed the significantly reduced bone-area (9.2 ± 3.9% [crown 9.9 ± 4.3%, stem 8.6 ± 3.6%]) compared to native humeri (21.2 ± 9.1%; p < 0.05). Bone-implant-contact was 20.5 ± 5.8% (crown 21.8 ± 6.2%, stem 19.2 ± 5.6%) which was confirmed by SEM and EDX. Altogether, CRSA shows satisfactory bone ingrowth at the interface suggesting sufficient primary stability to allow osseous integration. However, clear signs of stress shielding with an inhomogeneous and reduced bone stock were observed. The impact on the long-term-results is unclear requiring further investigation.

Increasing pullout strength of suture anchors in osteoporotic bone using augmentation--a cadaver study.

BACKGROUND: Rotator cuff tears are of increasing clinical impact in the physically active elderly patients. Recent research revealed, that a high percentage of these patients present with significant loss of bone mineral density at the insertion site of the rotator cuff, thereby compromising suture anchorage for operative repair. We therefore hypothesized that augmentation of suture anchors improves biomechanical properties in low bone quality. METHODS: 28 osteoporotic humeral heads were included in this biomechanical study. Bone quality at the anchor insertion sites (group 1: posterior-medial; group 2: anterior-lateral) within the greater tuberosity was analyzed using HR-pQCT (voxel size: 82µm). Anchor positions of identical quality were then randomized to either conventional screw anchorage or polymethylmethacrylat augmented screw anchorage. All anchors were cyclically ramp-loaded until pullout. FINDINGS: Pullout strength accounted for 226N in group I for conventional anchorage and for 332N in augmented technique. In group 2 (anterior-lateral) the pullout strength was 209N (conventional) and 304N (augmented). Pull-out strength of augmented screw anchors was significantly higher in both groups (p<0.05). INTERPRETATION: Compared to conventional insertion techniques, the cement augmentation technique increases the pullout strength of suture anchors in low bone quality significantly. Cement augmentation could therefore be a helpful tool for improved suture anchor stability, especially in locations of low bone quality.

Straight proximal humeral nails are surrounded by more bone stock in comparison to bent nails in an experimental cadaveric study.

BACKGROUND: In the management of proximal humeral fractures intramedullary implants with bent and straight shape of the proximal part of nail are available. Based on data from previous studies on bone distribution in the humeral head, we hypothesized, that higher densities might exist in the bone stock surrounding straight nails in comparison to their angulated counterparts. With a known positive correlation between bone density and mechanical stability, this could indicate potentially higher rigidity of osteosyntheses done with straight implants. METHODS: We performed high resolution peripheral quantitative computed tomographies of the potential straight and bent implant bearing regions of 27 cadaveric proximal humeri. The acquired data were analyzed for differences between straight and bent Volumes of Interest as well as intra- and interindividual bone stock distribution. RESULTS: For both straight and bent volumes of interest a considerably declining bone mineral density was found in craniocaudal direction. Mean densities of bent volumes were significantly lower in comparison to their corresponding straight counterparts (p < 0.01) Intra-individual comparison yielded high bivariate correlations of the corresponding Volumes of Interest of the right and the left side (p < 0.01). CONCLUSIONS: Based on the volumetric data a statistically relevant biomechanical superiority of straight shaped implants can be assumed. Since we found a rapid decrease of bone density in cranio-caudal direction, intramedullary implants should be anchored as proximally in the subcortical area as possible to minimize the risk of displacement or cutout. The high correlation between the Volumes of Interest of the corresponding right and left sides could aid in preoperative planning when considering an intra- or extramedullary approach.

Long-term functional outcomes (median 10 years) after locked plating for displaced fractures of the proximal humerus.

BACKGROUND: Locked plating has become an accepted treatment for displaced fractures of the proximal humerus. However, to our knowledge, long-term outcomes have not been reported. METHODS: Between February 2002 and March 2004, 121 patients with displaced proximal humeral fractures were treated by open reduction and locking plate fixation. Forty-three patients were available for 10-year (95% confidence interval [CI], 9.8-10.1) follow-up, including Constant score (CS), Disabilities of the Arm, Shoulder and Hand score, and Short Form 36 questionnaire. RESULTS: Of 43 patients (72% women; mean age at time of fracture repair, 58.2 years; 95% CI, 54.2-62.2), the absolute CS 10 years after surgery was 75.3 (95% CI, 69.2-81.4). The normalized CS was 88.4 (95% CI, 81.7-95.1), and the CS in percentage to the contralateral side (%CS) was 83.7 (95% CI, 78.5-88.9). In contrast, at 1 year, the CS was 73.9 (95% CI, 67.8-80.2, P = .774), the normalized CS was 87.2 (95% CI, 80.4-94.0; P = .765), and the %CS was 78.7 (95% CI, 71.5-85.8; P = .355). The CS at 10 years correlated with the CS at 1 year after surgery (r = 0.460; P < .01) and with patient gender (r = -0.424; P < .01), and it strongly correlated with patient age (r = -0.545; P < .001). CONCLUSIONS: Ten years after locked plating of displaced proximal humeral fractures, patients show good to excellent outcomes in the majority of cases with no relevant decline compared with the shoulder function 1 year after surgery. However, poor long-term outcome is seen in 16% of patients and relates to a low CS 1 year after surgery. Thus, patients developing poor long-term outcomes may be identified at an earlier stage.

Significant benefit for older patients after arthroscopic subacromial decompression: a long-term follow-up study.

BACKGROUND: Patients suffering from isolated subacromial impingement (SI) of their shoulder but who are resistant to other therapies benefit substantially from arthroscopic subacromial decompression (ASD) if they are young (<60 years). Although physical demands rise notably in the older population, it still remains unclear if surgery leads to better results in these patients. Therefore, the aim of this study was to focus on the impact of age on the functional outcome in elderly patients suffering from SI. METHODS: In this retrospective analysis, 307 patients (age range: 42-63 years) with isolated SI were enrolled. The 165 patients were allocated to physical therapy whereas 142 underwent ASD. The patient cohort was divided into two groups according to the median age (<57 years). Functional outcome was recorded using the Munich Shoulder Questionnaire (MSQ) allowing for qualitative self -assessment of the Constant, SPADI and Dark Scores. RESULTS: Median age was 57 (25%-75%: 48-63) years, follow-up was 55 (25%-75%: 25-87) months. In group I (age < 57 years, n = 165) no significant differences in outcome between physical therapy and ASD were detected. In contrast, in group II (age > 57 years; n = 142) the patients reported significantly better results after ASD in the overall MSQs. CONCLUSION: Despite their higher age, elderly patients with isolated SI actually benefit significantly from ASD in comparison to physical therapy.

X-treme CT analysis of cancellous bone at the rotator cuff insertion in human individuals with osteoporosis: superficial versus deep quality.

PURPOSE: Rotator cuff (RC) repair-especially in the elderly population-is problematic since the patients suffer to a high extent from bone mineral density loss at the reattachment site. Therefore, the study was primarily driven by the question whether it is possible to reach more or qualitatively better cancellous bone and thus a more stable postoperative result if anchors with greater length are used for RC repair and/or the conventional anchors are screwed deeper into the bone. In anatomical terms, the question is raised whether cancellous bone is of better quality close to or far off the RC enthesis. METHODS: Axial HRqCT scans (X-tremeCT, Scanco Medical) of 36 human cadaveric humeral heads (75 ± 11 years) were performed to determine the ratio of bone volume to total volume (BV/TV), trabecular thickness (Trab Th), number of trabecles (Trab N), trabecular separation (Trab Sp) as well as non-metric indices such as connectivity density (Conn Dens) and structure model index (SMI). Within the greater tuberosity (GT), 6 volumes of interest (VOI) (A1, B1, C1, A2, B2, C2), in the lesser tuberosity (LT) 2 VOIs (D1, D2) and one control VOI in the subchondral bone were set. The analyzed bone cylinder of each VOI was divided into a superficial and a deep portion. RESULTS: The parameters BV/TV, Trab N, Trab Th and Conn Dens in all volumes of the GT and LT revealed higher values in the superficial portion reaching different levels of significance (p < 0.001/<0.05). The only parameter presenting a higher value in the deep portion was Trab Sp, but this was the case for all GT and LT regions. Interestingly, the difference between the superficial and deep portion reached significance for the non-metric parameter SMI in no volume of the GT/LT, although the higher values were found superficially. CONCLUSIONS: Our data show that cancellous bone presents with decreasing bone quality when analyzing increasingly deeper portions of the bone cylinders of the GT and LT starting at the articular surface. This information seems to be crucial for shoulder surgeons, especially when treating elderly patients. Our results clearly prove that screwing in anchors to a deeper extent will not improve stability, since the deeper bone stock is of worse quality.

Age and gender as determinants of the bone quality of the greater tuberosity: a HR-pQCT cadaver study.

BACKGROUND: Age-dependent trabecular changes of the humeral head might weaken the fixation of suture anchors used for rotator cuff (RC) repair. This might lead to suture anchor loosening and thus compromise the integrity of the repair. The aim of this study was to analyze whether the trabecular microstructure within the RC footprint is influenced by age, gender or handedness. METHODS: Axial HR-pQCT scans (Scanco Medical) of 64 freshly frozen cadaveric human humeral head specimens (age 72.3 ± 17.4 years) were analyzed to determine the bone volume-to-total volume ratio (BV/TV), trabecular thickness (Trab Th), trabecular number (Trab N) and connectivity density (Conn Dens). Within the RC footprint, 2 volumes of interest (VOI), posteromedial (PM) and anterolateral (AL) and one control VOI in the subarticular bone (SC) were set. RESULTS: The highest BV/TV was found in SC: 0.22 ± 0.06% vs. PM: 0.04 ± 0.05% vs. AL: 0.02 ± 0.04%; p < 0.05. Trab Th accounted for 0.26 ± 0.05 µm in SC, 0.23 ± 0.09 µm in AL and 0.21 ± 0.05 µm in PM. In parallel, Trab N and Conn Dens were found to be the highest in SC. Gender analysis yielded higher values for BV/TV, Trab Th, Trab N and Conn Dens for PM in males compared to females (p < 0.05). There were no significant findings when comparing both sides. We furthermore found a strong inverse correlation between age and BV/TV, which was more pronounced in the female specimens (r = -0.72, p < 0.00001). CONCLUSIONS: The presented microarchitectural data allow for future subtle biomechanical testing comprising knowledge on age- and sex-related changes of the tuberosities of the humeral head. Furthermore, the insights on the trabecular structure of the humeral head of the elderly may lead to the development of new fixation materials in bone with inferior bone quality.

The Munich Shoulder Questionnaire (MSQ): development and validation of an effective patient-reported tool for outcome measurement and patient safety in shoulder surgery.

BACKGROUND: Outcome measurement in shoulder surgery is essential to evaluate the patient safety and treatment efficiency. Currently this is jeopardized by the fact that most patient-reported self-assessment instruments are not comparable. Hence, the aim was to develop a reliable self-assessment questionnaire which allows an easy follow-up of patients. The questionnaire also allows the calculation of 3 well established scoring systems, i.e. the Shoulder Pain and Disability Index (SPADI), the Constant-Murley Score (CMS), and the Disabilities of the Arm, Shoulder and Hand (DASH) Score. The subjective and objective items of these three systems were condensed into a single 30-questions form and validated against the original questionnaires. METHODS: A representative collective of patients of our shoulder clinic was asked to fill in the newly designed self-assessment Munich Shoulder Questionnaire (MSQ). At the same time, the established questionnaires for self-assessment of CONSTANT, SPADI and DASH scores were handed out. The obtained results were compared by linear regression analysis. RESULTS: Fifty one patients completed all questionnaires. The correlation coefficients of the results were r = 0.91 for the SPADI, r = -0.93 for the DASH and r = 0.94 for the CMS scoring system, respectively. CONCLUSIONS: We developed an instrument which allows a quantitative self-assessment of shoulder function. It provides compatible data sets for the three most popular shoulder function scoring systems by one single, short 30-item. This instrument can be used by shoulder surgeons to effectively monitor the outcome, safety and quality of their treatment and also compare the results to published data in the literature.

Fibrocartilage in various regions of the human glenoid labrum. An immunohistochemical study on human cadavers.

PURPOSE: The nature and the distribution of fibrocartilage at the human glenoid labrum are unclear, and a better understanding may help to restore its function in open and arthroscopic Bankart repair. Aim of this study was to describe the fibrocartilage extent within the labrum at clinically relevant sites of the glenoid in order to relate the molecular composition of the labrum to its mechanical environment. METHODS: Twelve fresh frozen human cadaveric shoulders (mean age 38 years) were obtained, and sections perpendicular to the glenoid rim at the 12, 2, 3, 4, 6 and 9 o' clock position were labelled with antibodies against collagen I and II, aggrecan and link protein. RESULTS: A fibrocartilaginous transition zone with a characteristic collagen fibre orientation was found in 81% of cases, evenly distributed (83-92%) around the glenoid rim. The percentage of labrum cross-sectional area comprised of fibrocartilage averaged 28% and ranged from 26% at 12 o'clock on the glenoid clock face to 30% at 3 o'clock. The highest amount of fibrocartilage (82%) was found in the region neighbouring the hyaline articular cartilage. In the region beyond the bony edge of the glenoid, fibrocartilage cross-sectional area did not exceed 12-17%. CONCLUSION: Fibrocartilage is present at all examined positions around the glenoid rim and constitutes up to 1/3 of the cross-sectional area of the labrum. In turn, the percentage of fibrocartilage in different regions of its cross-section varies considerably. The findings suggest that the penetration of fibrocartilaginous tissue may be reduced by avoiding the highly fibrocartilage transition zone during restoration of labral detachment.

Comparison of intraosseous versus central venous vascular access in adults under resuscitation in the emergency department with inaccessible peripheral veins.

INTRODUCTION: Current European Resuscitation Council (ERC) guidelines recommend intraosseous (IO) vascular access, if intravenous (IV) access is not readily available. Because central venous catheterisation (CVC) is an established alternative for in-hospital resuscitation, we compared IO access versus landmark-based CVC in adults with difficult peripheral veins. METHODS: In this prospective observational study we investigated success rates on first attempt and procedure times of IO access versus central venous catheterisation (CVC) in adults (≥ 18 years of age) with inaccessible peripheral veins under trauma or medical resuscitation in a level I trauma centre emergency department. RESULTS: Forty consecutive adults under resuscitation were analysed, each receiving IO access and CVC simultaneously. Success rates on first attempt were significantly higher for IO cannulation than CVC (85% versus 60%, p=0.024) and procedure times were significantly lower for IO access compared to CVC (2.0 versus 8.0 min, p<0.001). As for complications, failure of IO access was observed in 6 patients, while 2 or more attempts of CVC were necessary in 16 patients. No other relevant complications like infection, bleeding or pneumothorax were observed. CONCLUSIONS: IO vascular access is a reliable bridging method to gain vascular access for in-hospital adult patients under resuscitation with difficult peripheral veins. Moreover, IO access is more efficacious with a higher success rate on first attempt and a lower procedure time compared to landmark-based CVC.

Treatment of distal humeral fractures using conventional implants. Biomechanical evaluation of a new implant configuration.

BACKGROUND: In the face of costly fixation hardware with varying performance for treatment of distal humeral fractures, a novel technique (U-Frame) is proposed using conventional implants in a 180 degrees plate arrangement. In this in-vitro study the biomechanical stability of this method was compared with the established technique which utilizes angular stable locking compression plates (LCP) in a 90 degrees configuration. METHODS: An unstable distal 3-part fracture (AO 13-C2.3) was created in eight pairs of human cadaveric humeri. All bone pairs were operated with either the "Frame" technique, where two parallel plates are distally interconnected, or with the LCP technique. The specimens were cyclically loaded in simulated flexion and extension of the arm until failure of the construct occurred. Motion of all fragments was tracked by means of optical motion capturing. Construct stiffness and cycles to failure were identified for all specimens. RESULTS: Compared to the LCP constructs, the "Frame" technique revealed significant higher construct stiffness in extension of the arm (P = 0.01). The stiffness in flexion was not significantly different (P = 0.16). Number of cycles to failure was found significantly larger for the "Frame" technique (P = 0.01). CONCLUSIONS: In an in-vitro context the proposed method offers enhanced biomechanical stability and at the same time significantly reduces implant costs.

Malfunction of a Heimlich flutter valve causing tension pneumothorax: case report of a rare complication.

BACKGROUND: Thoracic injuries play an important role in major trauma patients due to their high incidence and critical relevance. A serious consequence of thoracic trauma is pneumothorax, a condition that quickly can become life-threatening and requires immediate treatment.Decompression is the state of the art for treating tension pneumothorax. There are many different methods of decompression using different techniques, devices, valves and drainage systems. Referring to our case report we would like to discuss the utilization of these devices. CASE PRESENTATION: We report of a patient suffering from tension pneumothorax despite insertion of a chest drain at the accident scene. The decompression was by tube thoracostomy which was connected to a Heimlich flutter valve. During air transportation the patient suffered from cardiorespiratory arrest with asystole and was admitted to the trauma room undergoing manual chest compressions. The initial chest film showed a persisting tension pneumothorax, despite the chest tube that had been correctly placed and connected properly to the Heimlich valve. We assume that the Heimlich valve leaves did not open up and thus tension pneumothorax was not released. CONCLUSION: We would like to raise awareness to the fact that if a Heimlich flutter valve is applied in the pre-hospital setting it should be used with caution. Failure in this type of valve may lead to recurrent tension pneumothorax.

A rapid method for the generation of uniform acellular bone explants: a technical note.

BACKGROUND: Bone graft studies lack standardized controls. We aim to present a quick and reliable method for the intra-operative generation of acellular bone explants. METHODS: Therefore, ovine cancellous bone explants from the iliac crest were prepared and used to test several methods for the induction of cell death. Over night heat inactivation was used as positive treatment control, methods to be investigated included UV light, or X- ray exposure, incubation in a hypotonic solution (salt-free water) and a short cycle of repeated freezing and thawing. RESULTS: Viability of treated and 2 days cultured bone explants was investigated by lactate dehydrogenase assay. Non-treated cultured control explants maintained around 50% osteocyte viability, while osteocyte survival after the positive treatment control was abolished. The most dramatic loss in cell viability, together with a low standard deviation, was a repeated cycle of freezing and thawing. CONCLUSIONS: To summarize, we present a freeze-thaw method for the creation of acellular bone explants, which is easy to perform, not time-consuming and provides consistent results.

Comparison of two intraosseous access devices in adult patients under resuscitation in the emergency department: A prospective, randomized study.

INTRODUCTION: Current guidelines recommend intraosseous (IO) vascular access in adults if peripheral venous access is unavailable. Most available data derive from children, animal models, cadaver studies or the prehospital setting. Therefore we compared two different IO access devices in adults under resuscitation in the hospital setting. PATIENTS AND METHODS: This prospective, randomized clinical study compared two different IO access devices in adults (>/=18 years of age) under trauma or medical resuscitation admitted to our emergency department with impossible peripheral venous access. Each adult was randomized to either spring-loaded BIG Bone Injection Gun or battery-powered EZ-IO. Outcome measures included success rates on first attempt, procedure times and complications. RESULTS: Forty consecutive adults under resuscitation were enrolled. Twenty patients received the BIG, another twenty patients the EZ-IO. Over all success rate on first attempt was 85% and mean procedure time 2.0min+/-0.9. Comparing the two devices, success rate on first attempt was 80% for the BIG versus 90% for the EZ-IO and mean procedure time was 2.2min+/-1.0 for the BIG versus 1.8min+/-0.9 for the EZ-IO. The differences between both IO devices were not statistically significant. No other relevant complications like infection, extravasation or bleeding were observed. CONCLUSIONS: IO vascular access was a reliable and safe method to gain rapid vascular access for in-hospital adult emergency patients under resuscitation. Further studies are necessary regarding comparative effectiveness of different IO devices.

Monoaxial versus polyaxial screw insertion in angular stable plate fixation of proximal humeral fractures: radiographic analysis of a prospective randomized study.

BACKGROUND: Monoaxial and polyaxial screw insertion are used in angular stable plating of displaced proximal humeral fractures. Aim of the study was to compare both fixation techniques by radiographic evaluation. METHODS: Prospective randomized treatment with monoaxial or polyaxial screw insertion in angular stable anatomic preshaped plates of displaced proximal humeral fractures. Analysis of standardized true anterior-posterior (true a.p.) and outlet-view radiographs at 1 day, 6 weeks, 3 months, and 6 months after surgery by two radiologists with respect to radiographic evidence of secondary varus displacement, cut out of screws, osteonecrosis, and hardware failure. Secondary varus displacement was defined as a varus decrease of the humeral head-shaft angle of > 10 degree in true a.p. radiographs. RESULTS: Sixty-six consecutive patients (48 women, [72.7%]; 18 men, [27.3%]; mean age 67.7 years [95% CI, 63.9-71.6]) with displaced proximal humeral fractures were evaluated in this study. Nineteen patients (29%) showed secondary varus displacement of > 10-degree angle. In 6 cases (9%), intra-articular cut out of screws was found. Furthermore, 1 case (2%) of nonunion was observed. No relationship between monoaxial and polyaxial screw insertion was found regarding occurrence of secondary varus displacement (monoaxial, 11/polyaxial, 8; p = 0.91) or screw cut out (monoaxial, 4/polyaxial, 2; p = 0.64). Prevalence of secondary varus displacement and hardware cut out was related to patients age (p = 0.02) and fracture pattern, according to Neer- and AO/OTA-classification (p < 0.001). The average immediate postoperative head-shaft angle was 135.2 degrees (CI, 132.3-138.1) in the group without radiographic complication, compared with 126.7-degree angle (CI, 123.6-129.7) among those with secondary varus displacement of > 10-degree angle and screw cut out (p < 0.001). Furthermore, in cases of an immediate postoperative head-shaft angle of < 130 degrees, there was a 48% incidence of secondary varus dislocation (n = 13) versus 15% in cases with a head-shaft angle > 130 degrees (n = 6, p = 0.004). CONCLUSION: Monoaxial and polyaxial screw insertion allow for mechanical stabilization in angular stable plating of unstable proximal humerus fractures. Radiographic evidence of secondary varus displacement of > 10-degree angle and screw cut out was seen similarly often in both fixation techniques. To avoid secondary varus displacement and screw cut out, restoration of a humeral head-shaft angle of > 130 degrees seems to be important in monoaxial and polyaxial fixation of proximal humeral fractures.

Assessment of bone quality within the tuberosities of the osteoporotic humeral head: relevance for anchor positioning in rotator cuff repair.

BACKGROUND: Tears of the rotator cuff are highly prevalent in patients older than 60 years, thereby presenting a population also suffering from osteopenia or osteoporosis. Suture fixation in the bone depends on the holding strength of the anchoring technique, whether a bone tunnel or suture anchor is selected. Because of osteopenic or osteoporotic bone changes, suture anchors in the older patient might pull out, resulting in failure of repair. HYPOTHESIS: The aim of our study was to analyze the bone quality within the tuberosities of the osteoporotic humeral head using high-resolution quantitative computed tomography (HR-pQCT). STUDY DESIGN: Descriptive laboratory study. METHODS: Thirty-six human cadaveric shoulders were analyzed using HR-pQCT. The mean bone volume to total volume (BV/TV) as well as trabecular bone mineral densities (trabBMDs) of the greater tuberosity (GT) and the lesser tuberosity (LT) were determined. Within the GT, 6 volumes of interest (VOIs) within the LT, and 2 VOIs and 1 control volume within the subchondral area beyond the articular surface were set. RESULTS: Comparing BV/TV of the medial and the lateral row, significantly higher values were found medially (P < .001). The highest BV/TV, 0.030% + or - 0.027%, was found in the posteromedial portion of the GT (P < .05). Regarding the analysis of the LT, no difference was found comparing the superior (BV/TV: 0.024% + or - 0.022%) and the inferior (BV/TV: 0.019% + or - 0.016%) portion. Analyzing trabBMD, equal proportions were found. An inverse correlation with a correlation coefficient of -0.68 was found regarding BV/TV of the posterior portion of the GT and age (P < .05). CONCLUSION: Significant regional differences of trabecular microarchitecture were found in our HR-pQCT study. The volume of highest bone quality resulted for the posteromedial aspect of the GT. Moreover, a significant correlation of bone quality within the GT and age was found, while the bone quality within the LT seems to be independent from it. CLINICAL RELEVANCE: The shape of the rotator cuff tear largely determines the bony site of tendon reattachment, although the surgeon has distinct options to modify anchor positioning. According to our results, placement of suture anchors in a medialized way at the border to the articular surface might guarantee a better structural bone stock.

Is the intraosseous access route fast and efficacious compared to conventional central venous catheterization in adult patients under resuscitation in the emergency department? A prospective observational pilot study.

BACKGROUND: For patients' safety reasons, current American Heart Association and European Resuscitation Council guidelines recommend intraosseous (IO) vascular access as an alternative in cases of emergency, if prompt venous catheterization is impossible. The purpose of this study was to compare the IO access as a bridging procedure versus central venous catheterization (CVC) for in-hospital adult emergency patients under resuscitation with impossible peripheral intravenous (IV) access. We hypothesised, that CVC is faster and more efficacious compared to IO access. METHODS: A prospective observational study comparing success rates and procedure times of IO access (EZ-IO, Vidacare Corporation) versus CVC in adult (>/=18 years of age) patients under trauma and medical resuscitation admitted to our emergency department with impossible peripheral IV catheterization was conducted. Procedure time was defined from preparation and insertion of vascular access type until first drug or infusion solution administration. Success rate on first attempt and procedure time for each access route was evaluated and statistically tested. RESULTS: Ten consecutive adult patients under resuscitation, each receiving IO access and CVC, were analyzed. IO access was performed with 10 tibial or humeral insertions, CVC in 10 internal jugular or subclavian veins. The success rate on first attempt was 90% for IO insertion versus 60% for CVC. Mean procedure time was significantly lower for IO cannulation (2.3 min +/- 0.8) compared to CVC (9.9 min +/- 3.7) (p < 0.001). As for complications, failure of IO access was observed in one patient, while two or more attempts of CVC were necessary in four patients. No other relevant complications, like infection, bleeding or pneumothorax were observed. CONCLUSION: Preliminary data demonstrate that IO access is a reliable bridging method to gain vascular access for in-hospital adult emergency patients under trauma or medical resuscitation with impossible peripheral IV access. Furthermore, IO cannulation requires significantly less time to enable administration of drugs or infusion solutions compared to CVC. Because CVC was slower and less efficacious, IO access may improve the safety of adult patients under resuscitation in the emergency department.