Treatment of Metaphyseal Defects in Plated Proximal Humerus Fractures with a New Augmentation Technique-A Biomechanical Cadaveric Study.

Background and Objectives: Unstable proximal humerus fractures (PHFs) with metaphyseal defects-weakening the osteosynthesis construct-are challenging to treat. A new augmentation technique of plated complex PHFs with metaphyseal defects was recently introduced in the clinical practice. This biomechanical study aimed to analyze the stability of plated unstable PHFs augmented via implementation of this technique versus no augmentation. Materials and Methods: Three-part AO/OTA 11-B1.1 unstable PHFs with metaphyseal defects were created in sixteen paired human cadaveric humeri (average donor age 76 years, range 66-92 years), pairwise assigned to two groups for locked plate fixation with identical implant configuration. In one of the groups, six-milliliter polymethylmethacrylate bone cement with medium viscosity (seven minutes after mixing) was placed manually through the lateral window in the defect of the humerus head after its anatomical reduction to the shaft and prior to the anatomical reduction of the greater tuberosity fragment. All specimens were tested biomechanically in a 25° adduction, applying progressively increasing cyclic loading at 2 Hz until failure. Interfragmentary movements were monitored by motion tracking and X-ray imaging. Results: Initial stiffness was not significantly different between the groups, p = 0.467. Varus deformation of the humerus head fragment, fracture displacement at the medial humerus head aspect, and proximal screw migration and cut-out were significantly smaller in the augmented group after 2000, 4000, 6000, 8000 and 10,000 cycles, p ≤ 0.019. Cycles to 5° varus deformation of the humerus head fragment-set as a clinically relevant failure criterion-and failure load were significantly higher in the augmented group, p = 0.018. Conclusions: From a biomechanical standpoint, augmentation with polymethylmethacrylate bone cement placed in the metaphyseal humerus head defect of plated unstable PHFs considerably enhances fixation stability and can reduce the risk of postoperative complications.

Clinical outcomes in latissimus dorsi transfer single- versus double-incision technique.

BACKGROUND/HYPOTHESIS: In patients with irreparable postero-superior rotator cuff lesions, a latissimus dorsi transfer (LDT) is performed. For this surgery, different techniques are used. In this study, we aim to compare the patient's functional outcome after treatment with modified L'Episcopo "single-incision" and modified Gerber "double-incision" technique for LDT. METHODS: 44 patients with irreparable postero-superior rotator cuff ruptures, refractory to physiotherapeutic treatment were included. 21 patients were treated using a modified L'Episcopo "single-incision", 23 patients with modified Gerber "double-incision" surgical approach. All patients had full-thickness tears of at least two complete tendons, and all had fully functioning deltoid and subscapularis muscles. Preoperatively, there were statistically significant differences between the two groups in all preoperative CMS sub-parameters except "power" and "pain". In the postoperative follow-up, a functional assessment using "Constant-Murley Score" (CMS) and "Age- and gender-related CMS" was conducted. STUDY DESIGN: Retrospective-comparative trial. RESULTS: There were no statistically significant differences between age, sex and time of follow-up between the two study groups (p > 0.05). The mean age was 59.2(± 6.3) years, and the mean follow-up time was 45.4(± 9.3) months for both groups taken together. Mean CMS improved for both groups together from 24.2 ± 8.2 points prior to surgery, to 62.8 ± 17.4 points after a mean follow-up time of 45.4 ± 9.3 months post surgery. The patients treated with "single-incision" surgery (n = 21) gained significantly (p < 0.001) more in CMS and all CMS-sub-scoring parameters except power and pain, compared to the patients treated with "double-incision" technique (n = 23). CONCLUSION: This survey shows appealing post-operative functional outcome in patients with irreparable postero-superior rotator cuff lesions treated with two different techniques for LDT. We believe that the presentation of these methods and their results might encourage shoulder surgeons to implement these techniques. Especially the "single-incision" LDT surgery might be a more accustomed technique for many shoulder surgeons well trained in the deltopectoral approach.

A Novel Technique for Treatment of Metaphyseal Voids in Proximal Humerus Fractures in Elderly Patients.

Background and Objectives: The treatment of proximal humerus fractures in elderly patients is challenging, with reported high complication rates mostly related to implant failure involving screw cut-out and penetration. Metaphyseal defects are common in osteoporotic bone and weaken the osteosynthesis construct. A novel technique for augmentation with polymethylmethacrylate (PMMA) bone cement was developed for the treatment of patients in advanced age with complex proximal humerus fractures and metaphyseal voids, whereby the cement was allowed to partially cure for 5-7 min after mixing to achieve medium viscosity, and then it was manually placed into the defect through the traumatic lateral window with a volume of 4-6 mL per patient. The aim of this retrospective clinical study was to assess this technique versus autologous bone graft augmentation and no augmentation. Materials and Methods: The outcomes of 120 patients with plated Neer three- and four-part fractures, assigned to groups of 63 cases with no augmentation, 28 with bone graft augmentation and 29 with cement augmentation, were assessed in this study. DASH, CS, pain scores and range of motion were analyzed at 3, 6 and 12 months. Statistical analysis was performed with factors for treatment and age groups, Neer fracture types and follow-up periods, and with the consideration of age as a covariate. Results: DASH and CS improved following cement augmentation at three and six months compared to bone grafting, being significant when correcting for age as a covariate (p ≤ 0.007). While the age group had a significant effect on both these scores with worsened values at a higher age for non-augmented and grafted patients (p ≤ 0.044), this was not the case for cement augmented patients (p ≥ 0.128). Cement augmentation demonstrated good clinical results at 12 months with a mean DASH of 10.21 and mean CS percentage of 84.83% versus the contralateral side, not being significantly different among the techniques (p ≥ 0.372), despite the cement augmented group representing the older population with more four-part fractures. There were no concerning adverse events specifically related to the novel technique. Conclusions: This study has detailed a novel technique for the treatment of metaphyseal defects with PMMA cement augmentation in elderly patients with complex proximal humerus fractures and follow-up to one year, whereby the cement was allowed to partially cure to achieve medium viscosity, and then it was manually placed into the defect through the traumatic lateral window. The results demonstrate clinically equivalent short-term results to 6 months compared to augmentation with bone graft or no augmentation-despite the patient group being older and with a higher rate of more severe fracture patterns. The technique appears to be safe with no specifically related adverse events and can be added in the surgeon's armamentarium for the treatment of these difficult to manage fractures.

Nail Versus Plate: A Biomechanical Comparison of a Locking Plate Versus an Intramedullary Nail With an Angular Stable Locking System in a Shoulder Simulator With Active Muscle Forces Using a Two-Part Fracture Model.

OBJECTIVES: To compare a locking compression plate versus an intramedullary nail with an angular stable locking system (ASLS) using a 2-part fracture model in a shoulder test bench. METHODS: Twelve fresh frozen humeri were used for biomechanical testing in a shoulder simulator. A 2-part fracture model, with and without medial cortical support, was used to compare the locking plate and a nail with an ASLS. The varus impaction, varus per cycle motion, tilt, and tilt per cycle were analyzed. RESULTS: No significant differences for the resulting forces in the glenoid fossa were evaluated. The stable fracture model showed no significant differences for the 2 groups. The median varus impaction was -0.96 degrees (range -0.55 to -4.26 degrees) in the plate group and 0.5 degrees (range -3.06 to 0.98 degrees) in the nail group, after 500 cycles of cyclic loading in the unstable fracture model. The plate group showed a significantly higher median varus impaction per cycle motion and median varus impaction at the 200th, 300th, and 400th cycle of physiological loading. CONCLUSIONS: The intramedullary nail with the ASLS could be an alternative for patients suffering from osteoporosis and comorbidities.

Incidence and severity of electric scooter related injuries after introduction of an urban rental programme in Vienna: a retrospective multicentre study.

PURPOSE: Electric scooters (e-scooters) are an emerging way of mobility in cities around the world. Despite quickly rising numbers of e-scooters, limited studies report on incidence and severity of e-scooter-associated injuries. The aim of our study was to report on these injuries and identify potential protective measures to ultimately decrease e-scooter-associated morbidity. METHODS: We performed a retrospective multicentre study including all patients, who were admitted to three major trauma departments in Vienna from May 2018 to September 2019. We analysed patients' data, including demographics, injury pattern, types of injury and subsequent treatment. RESULTS: A total number of 175 patients (115 males, 60 females) sustained e-scooter-associated injuries. Patients' mean age was 34.4 years [4-74]. While the mean Injury Severity Score (ISS) was 3.4, 11 patients presented with an ISS ≥ 9 and 2 patients with an ISS ≥ 16. ISS increased with age. Older patients (≥ 40 years) presented a significantly higher ISS than younger patients (< 40 years) (P = 0.011). Seventy-one patients (40.6%) sustained major injuries affecting head (35.2%) and upper extremities (36.6%). Twenty-three patients (13.1%) required surgery leading to hospitalization of 11 days on average [1-115]. E-scooter-associated injuries increased during late afternoon plateauing at 8.00 pm. However, the largest share of patients (39.2%) sustained their injuries during early night (8.00 pm to 1.59 am) with especially young adults (19-39 years) being at risk. CONCLUSION: The popularity of rideshare e-scooters across cities worldwide seems to be on the rise, so are e-scooter-associated injuries. These injuries should be considered high-energy trauma affecting primarily head and upper extremity; indeed, 17.7% sustained major head injuries. Therefore, the mandatory use of a helmet seems to be adequate to decrease head injury-associated morbidity. Ultimately, given the remarkably high rates of nighttime injuries, an e-scooter ban during night could further cut injury numbers in half.

Does cement augmentation of the screws in angular stable plating for proximal humerus fractures influence the radiological outcome: a retrospective assessment.

BACKGROUND: Screw-tip augmentation in angular stable plating offers new possibilities for the treatment of complex proximal humerus fractures. This retrospective analysis was performed to evaluate the radiological outcome of proximal humerus fractures treated with angular stable plates and additional screw-tip cement augmentation in patients over the age of 60. MATERIALS AND METHODS: A retrospective single centre analysis was conducted from June 2013 to December 2016. The minimum follow-up time was set to 6 months after surgery. Anatomical reduction and fixation were evaluated in respect to reattached tuberosities to the head fragment and the adequate restoration of the calcar area not showing any valgus or varus malalignment. Complete fracture healing was determined 3 months after surgery. Any failures such as secondary displacement, primary screw perforation, intraarticular cement leakage and avascular necrosis of the humeral head with concomitant screw cut-out were assessed. RESULTS: In total, 24 patients (21 females; 3 males) at a median age of 77.5 (62-96) years were included. Five 2-part, twelve 3-part and seven 4-part fractures were detected. The measured median BMD value of 23 patients was 78.4 mg/cm3 (38.8-136.9 mg/cm3). Anatomical reduction was achieved in 50% of the patients. In most cases, the A level screws and the B1 screw were augmented with bone cement by a median of 7 (5-9) head screws used. Postoperative varus displacement was not detected in any of the patients. One patient (4.2%) sustained an early secondary displacement. Intraarticular cement leakage was detected in 3 patients (2 head-split fractures). Avascular necrosis of the humeral head was observed in 4 patients (16.7%). Revision surgery was necessary in four cases, using hemiarthroplasty twice and reverse shoulder arthroplasty the other two times. CONCLUSION: Screw-tip augmentation in angular stable plating for proximal humerus fracture treatment showed a low secondary displacement rate of 4.2% in patients suffering from poor bone quality. Nevertheless, the occurrence of avascular necrosis of the humeral head with mainly severe fracture patterns observed in this study was higher compared to previously reported results in the literature. Cement augmentation in head-split fractures is not recommended, considering the high risk of an intraarticular cement leakage.

Cement augmentation of the proximal humerus internal locking system in elderly patients: a multicenter randomized controlled trial.

INTRODUCTION: Cement augmentation of the proximal humerus internal locking system (PHILOS) screws might reduce complication rates in osteoporotic bones. This study compared the risk of mechanical failure during the first year after PHILOS™ treatment of proximal humerus fractures (PHF) without (control group) and with (augmented group) screw augmentation. Secondary objectives were to report shoulder functions, quality of life (QoL), adverse events (AEs), and reoperation rates. MATERIALS AND METHODS: This multicenter randomized trial enrolled patients aged ≥ 65 years with displaced/unstable PHF from eight European centers. Randomization was performed during surgery through sealed opaque envelopes. Mechanical failures were assessed by two independent reviewers via radiographs, shoulder function by Quick DASH, SPADI, and Constant Murley scores, and QoL by EQ-5D. Follow-ups were planned at postoperative 6 weeks, 3, 6, and 12 months. RESULTS: The preliminary analysis of 6-week radiographs of the first 59 enrolled patients suggested a mechanical failure rate lower than expected and the difference between groups was too small to be detected by the planned sample size of 144. The trial was prematurely terminated after 67 patients had been enrolled: 34 (27 eligible) in the control group and 33 (29 eligible) in the augmented group. Follow-ups were performed as planned. Nine patients had mechanical failures and the failure rates (95% CI) were: augmented group, 16.1% (5.5; 33.7); control group, 14.8% (4.2; 33.7); the relative risk (95% CI) for the augmented group was 1.09 (0.32; 3.65) compared to the control group (p = 1.000). No statistically significant differences in shoulder function, QoL, and AEs were observed between study groups at 1 year. Nine patients (15.8%) underwent a revision. CONCLUSIONS: Due to premature termination, the study was underpowered. A larger study will be necessary to determine if cement augmentation lowers the risk of mechanical failure rate.

Biomechanical evaluation of cable and suture cerclages for tuberosity reattachment in a 4-part proximal humeral fracture model treated with reverse shoulder arthroplasty.

BACKGROUND: Sufficient tuberosity fixation in proximal humeral fractures treated with shoulder arthroplasty is essential to gain a good clinical outcome. This biomechanical study evaluated the strength of the reattached tuberosities in reverse total shoulder arthroplasty fixed with cables or with sutures in a cerclage-like technique. Considering the mechanical advantages of flexible titanium alloy cables compared with conventional sutures for cerclage-like fixations, we hypothesized that titanium alloy cables would achieve higher fixation strengths of the tuberosities compared with heavy nonabsorbable sutures. METHODS: A 4-part fracture was created on 8-paired proximal human humeri. The tuberosities were reduced anatomically and fixed by 2 heavy nonabsorbable sutures (suture group) or by two 1-mm titanium alloy cables (cable group) in a cerclage-like technique around the neck of the prosthesis. The humeri were placed in a custom-made test setup enabling internal and external rotation. Cyclic loading with a stepwise increasing load magnitude was applied with a material testing machine, starting with 1 Nm and increasing the load by 0.25 Nm after each 100th cycle until failure of the fixation occurred (>15° rotation of the tuberosities). Any motion of the tuberosities was measured with a 3-dimensional ultrasound motion analysis system. RESULTS: Overall, the cable group reached 1414 ± 372 cycles, and the suture group reached 1257 ± 230 cycles until the fixations failed (P = .313). The suture group showed a significantly higher rotation of the lesser tuberosity relative to the humerus shaft axis after 200, 400, and 600 cycles compared with the cable group (P = .018-.043). CONCLUSIONS: Tuberosities reattached with cable cerclages showed higher fixation strength and therefore less rotation compared with suture cerclages in a 4-part proximal humeral fracture model treated with reverse total shoulder arthroplasty. Whether this higher fixation strength results in higher bony ingrowth rates of the tuberosities and thus leads to a better clinical outcome needs to be investigated in further clinical studies.

The female geriatric proximal humeral fracture: protagonist for straight antegrade nailing?

INTRODUCTION: Straight antegrade humeral nailing (SAHN) has become a standard technique for the surgical fixation of proximal humeral fractures, which predominantly affect elderly females. The nail's proximal anchoring point has been demonstrated to be critical to ensure reliable fixation in osteoporotic bone and to prevent iatrogenic damage to the superior rotator cuff bony insertion. Anatomical variations of the proximal humerus, however, may preclude satisfactory anchoring of the nail's proximal end and may bare the risk of rotator cuff violation, even though the nail is inserted as recommended. The aim of this study was to evaluate the anatomical suitability of proximal humeri of geriatric females aged 75 years and older for SAHN. Specifically, we sought to assess the proportion of humeri not anatomically amenable to SAHN for proximal humeral fracture. MATERIALS AND METHODS: A total of 303 proximal humeri of 241 females aged 75 years and older (mean age 84.5 ± 5.0 years; range 75-102 years) were analyzed for this study. Multiplanar two-dimensional reformations (true ap, true lateral, and axial) were reconstructed from shoulder computed tomography (CT) data sets. The straight antegrade nail's ideal entry point, "critical point" (CP), and critical distance (CD; distance between ideal entry point and CP) were determined. The rate of proximal humeri not anatomically suitable for SAHN (critical type) was assessed regarding proximal reaming diameters of currently available straight antegrade humeral nails. RESULTS: Overall, 35.6% (108/303) of all proximal humeri were found to be "critical types" (CD <8 mm) as to the recommended minimal proximal reaming diameter of 10 mm of straight antegrade nails currently in use. Moreover, 43.2% (131/303) of the humeri were considered "critical types" with regard to the alternatively used larger proximal reaming diameter of 11.5 mm. Mean CD was 9.0 ± 1.7 mm (range 3.5-13.5 mm) and did not correlate with age (r = -0.04, P = 0.54). No significant differences in CD and rate of "critical types" were found between left and right humeri as well as between females aged between 75 and 84 years (n = 151) and females aged 85 and older (n = 152). CONCLUSIONS: More than a third of proximal humeri of geriatric females are "critical types" as to SAHN and may, therefore, be at risk for procedure-related complications, such as rotator cuff violation, fixation failure, and potential malreduction. In view of this finding, we recommend to routinely analyze multiplanar CT reformations of the uninjured contralateral side prior to surgery to improve selection of patients for SAHN and to minimize foreseeable complications. For "critical type" humeri, an alternative surgical procedure should be considered.

Biomechanical evaluation of straight antegrade nailing in proximal humeral fractures: the rationale of the "proximal anchoring point".

PURPOSE: Varus failure is one of the most common failure modes following surgical treatment of proximal humeral fractures. Straight antegrade nails (SAN) theoretically provide increased stability by anchoring to the densest zone of the proximal humerus (subchondral zone) with the end of the nail. The aim of this study was to biomechanically investigate the characteristics of this "proximal anchoring point" (PAP). We hypothesized that the PAP would improve stability compared to the same construct without the PAP. METHODS: Straight antegrade humeral nailing was performed in 20 matched pairs of human cadaveric humeri for a simulated unstable two-part fracture. RESULTS: Biomechanical testing, with stepwise increasing cyclic axial loading (50-N increments each 100 cycles) at an angle of 20° abduction revealed significantly higher median loads to failure for SAN constructs with the PAP (median, 450 N; range, 200-1.000 N) compared to those without the PAP (median, 325 N; range, 100-500 N; p = 0.009). SAN constructs with press-fit proximal extensions (endcaps) showed similar median loads to failure (median, 400 N; range, 200-650 N), when compared to the undersized, commercially available SAN endcaps (median, 450 N; range, 200-600 N; p = 0.240). CONCLUSIONS: The PAP provided significantly increased stability in SAN constructs compared to the same setup without this additional proximal anchoring point. Varus-displacing forces to the humeral head were superiorly reduced in this setting. This study provides biomechanical evidence for the "proximal anchoring point's" rationale. Straight antegrade humeral nailing may be beneficial for patients undergoing surgical treatment for unstable proximal humeral fractures to decrease secondary varus displacement and thus potentially reduce revision rates.

Computed tomography-based prediction of the straight antegrade humeral nail's entry point and exposure of "critical types": truth or fiction?

BACKGROUND: Straight antegrade intramedullary nailing of proximal humerus fractures has shown promising clinical results. However, up to 36% of all humeri seem to be "critical types" in terms of the potential violation of the supraspinatus (SSP) tendon footprint by the nail's insertion zone. The aims of this study were to evaluate if a computed tomography (CT) scan could reliably predict the nail's entry point on the humeral head and if it would be possible to preoperatively estimate the individual risk of iatrogenic violation of the SSP tendon footprint by evaluating the uninjured contralateral humerus. METHODS: Twenty matched pairs of human cadaveric shoulders underwent CT scans, and the entry point for an antegrade nail as well as measurements regarding critical distances between the entry point and the rotator cuff were determined. Next, gross anatomic measurements of the same data were performed and compared. Furthermore, specimens were reviewed for critical types. RESULTS: Overall, 42.5% of all specimens were found to be critical types. The CT measurements exhibited excellent intra-rater and inter-rater reliability (intraclass correlation coefficients >0.90). Similarly, excellent agreement between the CT scan and gross anatomic measurements in contralateral shoulders (intraclass correlation coefficients >0.88) was found. CONCLUSION: Assessing the uninjured contralateral side, CT can reliably predict the entry point in antegrade humeral nailing and preoperatively identify critical types of humeral heads at risk of iatrogenic implantation damage to the SSP tendon footprint. This study may help surgeons in the decision-making processon which surgical technique should be used without putting the patient at risk for iatrogenic, implant-related damage to the rotator cuff.

Significant Differences Between Local Reporting and Central Assessment of Radiographic Complications in a Prospective, Multicenter Study About Locking Plate Fixation of Proximal Humerus Fractures.

OBJECTIVES: To compare reporting outcomes of radiographic complications conducted by an independent review board and the responsible on-site study personnel in a multicenter study about locking plate fixation of proximal humeral fractures. DESIGN: Prospective, multicenter study; setting: 9 level I trauma centers. PATIENTS: One hundred fifty patients (age 50-90) with a radiographically confirmed displaced proximal humeral fracture fixed with a locking plate were included in the study. INTERVENTION: All radiographic data were reevaluated by an independent review board according to predefined criteria. MAIN OUTCOME MEASUREMENTS: Differences in outcomes between the review board and the on-site assessment were analyzed with a paired t test. Interrater agreements between the central review board and on-site assessments were estimated by means of kappa statistics. RESULTS: The review board revealed significantly more radiographic complications than the on-site assessment (P = 0.006), except for the complication "head necrosis." The interrater agreement was slight to moderate in all calculated categories. CONCLUSIONS: Implementation of a complication review board using predefined criteria is recommended for clinical studies to prevent underreporting of radiographic complications by on-site assessment.

A Simple Method for Measurement of Femoral Anteversion-Validation and Assessment of Reproducibility.

OBJECTIVES: To propose a simple method for measurement of femoral anteversion (AV) with a conventional fluoroscope, to evaluate the interobserver and intraobserver reliability of this method on the basis of human cadaver femurs, and to validate such method on the basis of computed tomography (CT). METHODS: Fourteen human cadavers with 28 intact femurs were included in the study. Three blinded observers measured femoral AV of the specimen with a fluoroscope. The session was repeated 8 weeks later and CT of the femurs were performed. Mean AV values and the difference between single and mean AV values were calculated. Interobserver/intraobserver reliability of the proposed method was assessed. Correlation between AV values measured with fluoroscope and CT was calculated. RESULTS: Mean AV was 18.1° when measured with fluoroscope and 19.2° when measured with CT. Mean differences between single AV values were 2.2° with fluoroscope and 2.5° with CT. The mean maximum observer variation per specimen was 8.8°. Interobserver reliability was excellent (intraclass correlation coefficient: 0.853) and intraobserver reliability was good (intraclass correlation coefficient: 0.682). A high correlation was found between AV values measured with fluoroscope and CT (rho = 0.739, P < 0.01). CONCLUSION: The presented technique allows reliable and simple measurement of femoral AV with a conventional fluoroscope. The mean interobserver variation is comparable to what has been reported for CT. Maximum interobserver variation was <15° in all specimens. A clinical study will be necessary to prove the value of this technique for intraoperative adjustment of femoral AV according to the intact contralateral side.

The relevance of neutral arm positioning for true ap-view X-ray to provide true projection of the humeral head shaft angle.

INTRODUCTION: Textbooks commonly recommend using the true anterior-posterior (ap)-view with the patient's arm in a sling and therefore in internal rotation (IR) for radiologic diagnostic assessment of the proximal humerus after trauma. However, IR or external rotation (ER) may affect the projection of the head shaft angle (HSA) and therefore bias the diagnostic conclusion significantly. We hypothesized that neutral rotation (NR) of the arm is mandatory for true ap-view to provide true projection of the HSA. MATERIALS AND METHODS: A simplified geometrical model of the proximal humerus was used to examine the influence of different arm positions and angulations of the central ray in relation to the projection of the HSA. RESULTS: Both ER and IR misleadingly suggested an increased valgus angle. Simulating the true ap-view with the central ray in cranio-caudal direction, IR changed the projection of the HSA substantially. CONCLUSION: In conclusion, standard fixation of the patient's arm in a shoulder sling in IR for true ap-view may result in an oblique projection, potentially leading to incorrect surgical implications. To prevent misdiagnosed valgus or varus angulation, NR of the arm should be obeyed when performing true ap-view X-ray. We, therefore, highly recommend to overcome the traditionally arm position, ensuring the true amount of dislocation to assure correct surgical implications and comparable follow-up examinations.

Significant differences between local reporting and central assessment of radiological complications in a prospective, multicenter study about locking plate fixation of proximal humerus fractures.

OBJECTIVES: To compare radiological complication reporting outcomes undertaken by an independent review board and the responsible on-site study personnel in a multicenter study about locking plate fixation of proximal humeral fractures. DESIGN: prospective, multicenter study SETTING:: Level I trauma centers PATIENTS:: One-hundred and fifty patients with a radiological confirmed, closed, displaced proximal humeral fracture fixed with a locking plate and aged between fifty and ninety years. INTERVENTION: Re-evaluation of all radiological data according to pre-defined criteria after finished collection of all study radiographs by an independent review board. MAIN OUTCOME MEASUREMENTS: Differences in outcomes between the review board and the sites assessment were tested with a paired t-test. Inter-rater agreements between the central review board and sites assessments were estimated by means of kappa statistics. RESULTS: The review board revealed significant more radiological complications than the sites assessment (p = 0.006), except for the complication 'head necrosis'. The inter-rater agreement was slight to moderate in all calculated categories. CONCLUSIONS: To prevent underreporting of radiological complications by on-site assessment, the implementation of a complication review board, using pre-defined criteria, is recommended for clinical studies that focus on radiological complications.

Allogenic bone grafting for augmentation in two-part proximal humeral fracture fixation in a high-risk patient population.

INTRODUCTION: The surgical fixation of unstable, varus displaced two-part fractures of the proximal humerus remains challenging. MATERIALS AND METHODS: In a case series of 10 non-compliant, high-risk patients (median age 63 years; range 52-78), a cancellous allograft was used to augment plate fixation of the fractures. RESULTS: After a median follow-up of 28.5 months, all but one fracture were healed, with the bony allografts incorporated without any systemic or local complications. No significant loss of reduction or evidence of avascular necrosis of the humeral head was seen. The median Constant-Murley Score was 72.0 (range 45-86). Median pain on a visual analog scale was 1 (range 0-7). Median values for the range of motion were flexion: 155° (range 90-170), abduction: 168° (range 95-180) and external rotation: 43° (range: 30-50). Compared to the uninjured contralateral side, flexion was impaired by 13 %, abduction by 14 %, and external rotation by 15 %. Median abduction power was 64 % of the uninjured side. The median varus displacement was 51° (range 45-59) preoperatively, 4° (range -5 to 19) intraoperatively, and 13° (range 1-18) at the time of the final follow-up, relating to an improvement of 38° compared to the preoperative status. CONCLUSIONS: The augmentation of proximal humeral fracture fixation using a cancellous allograft might be a viable and reliable alternative to prevent early varus failure and to, moreover, lead to bony union in a non-compliant or high-risk patient population.

The Influence of Local Bone Density on the Outcome of One Hundred and Fifty Proximal Humeral Fractures Treated with a Locking Plate.

BACKGROUND: There is biomechanical evidence that bone density predicts the mechanical failure of implants. The aim of this prospective study was to evaluate the influence of local bone mineral density on the rate of mechanical failure after locking plate fixation of proximal humeral fractures. METHODS: We enrolled 150 patients who were from fifty to ninety years old with a closed, displaced proximal humeral fracture fixed with use of a locking plate from July 2007 to April 2010. There were 118 women and thirty-two men who had a mean age of sixty-nine years. Preoperative computed tomography (CT) scans were done to assess bone mineral density of the contralateral humerus, and dual x-ray absorptiometry of the distal end of the radius of the unaffected arm was conducted within the first six weeks postoperatively. At follow-up evaluations at six weeks, three months, and one year postoperatively, pain, shoulder mobility, strength, and multiple functional and quality-of-life outcome measures (Disabilities of the Arm, Shoulder and Hand [DASH] questionnaire; Shoulder Pain and Disability Index [SPADI]; Constant score; and EuroQuol-5D [EQ-5D]) were done and standard radiographs were made. We defined mechanical failure as all complications related to bone quality experienced within one year. RESULTS: After locking plate fixation, fifty-three (35%) of 150 patients had mechanical failure; loss of reduction and secondary screw loosening with perforation were common. CT assessments of local bone mineral density showed no difference between patients with and without mechanical failure (89.82 versus 91.51 mg/cm3, respectively; p = 0.670). One-year DASH, SPADI, and Constant scores were significantly better for patients without mechanical failure (p ≤ 0.05). CONCLUSIONS: We did not find evidence of an association between bone mineral density and the rate of mechanical failures, which may suggest that patients with normal bone mineral density are less prone to sustain a proximal humeral fracture. Future studies should target other discriminating factors between patients with and without mechanical failure. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Biomechanical comparison of an angular stable plate with augmented and non-augmented screws in a newly developed shoulder test bench.

BACKGROUND: The proximal humeral fracture is one of the most common fractures. Although there are a number of treatment options available, the clinical outcomes in geriatric patients are still unsatisfactory. Therefore, the aim of this study was to investigate the biomechanical behaviour of an angular stable plate with either augmented or non-augmented screws using two different fracture models in a shoulder test bench with active muscle forces. METHODS: Six paired fresh-frozen humeri were loaded into a shoulder test bench simulating ab- and adduction between 15 and 45° induced by active muscle forces. The bone mineral density was measured by a quantitative CT. A two-part fracture model (stable and an unstable) was used to investigate the different biomechanical behaviours of the PHILOS plate, either utilising cannulated screws, allowing in situ augmentation, or without utilising augmented screws. Four screws were augmented with 0.5ml PMMA cement. FINDINGS: The in vitro-measured resulting forces in the glenoid fossa were comparable to the in vivo forces generated in shoulder arthroplasties. Under stable conditions, the per cycle motion and varus impaction tilting showed no significant difference. In the unstable state, the augmented group showed a maximum of 0.81° per cycle motion and a maximum varus impaction of -1.46° compared to the non-augmented maximum of 2.31° per cycle motion and maximum varus impaction of -4.26° (P<0.05). INTERPRETATION: In an unstable fracture model under dynamic testing conditions, augmentation leads to a decreased per cycle motion and varus impaction of the humeral head.