Injury Mechanism of Acute Anterior Shoulder Dislocation Associated with Glenoid and Greater Tuberosity Fractures: A Study Based on Fracture Morphology.

OBJECTIVE: Based on the morphological characteristics of glenoid and greater tuberosity (GT) fractures and the relationship between them, we explored the injury mechanism of acute anterior shoulder dislocation associated with glenoid and GT fractures. METHODS: From December 2013 to December 2019, we retrospectively reviewed the clinical data of patients who were diagnosed with acute anterior shoulder dislocation associated with glenoid and GT fractures in our hospital. According to the fracture site, a glenoid fracture group and a greater tuberosity fracture (GT) group were established, and the morphological characteristics of both glenoid and GT fractures were measured and statistically analyzed. RESULTS: A total of 41 patients (43 shoulders) met the inclusion criteria (39 unilateral shoulders and 2 bilateral shoulders). The mean age was 50.21 years (range, 22-71 years). A total of 27 shoulder injuries (62.8%) were split GT fractures and 33 shoulder injuries (76.7%) were combined with rotator cuff tears. The mean size of glenoid fragments was 30.16% and the mean displacement was 8.85 mm. The mean size of GT fragments was 28.43 mm. The mean superoinferior and anteroposterior displacements of the GT fragment were 6.77 mm and 4.96 mm, respectively. There was a negative correlation between the size of glenoid and GT fracture fragments (r = -0.64, P < 0.05). The glenoid fragments in the Ideberg type Ia glenoid fracture group were smaller than those in the Ideberg type II glenoid fracture group (28.41% and 40.95%, respectively), while the size of GT fragments in the type Ia group were larger than those in the type II group (29.77 mm and 20.21 mm, respectively) (P < 0.05). The GT fragments in the split GT fracture group were larger than those in the avulsion or depression GT fracture group (33.69 mm, 19.07 mm and 21.12 mm, respectively), while the size of glenoid fragments in the split GT fracture group were smaller than those in the avulsion or depression GT fracture group (23.57%, 41.37%, and 43.42%, respectively) (P < 0.05). As for the displacement direction of GT fragments, depression fractures were mainly inferior displacements, avulsion fractures were mainly anterosuperior displacements, while split fractures were mainly posteroinferior displacements (P < 0.05). Multiple regression analysis suggested that the type and the fragment size of GT fractures have a significant influence on the size of glenoid fragments. CONCLUSION: Acute anterior shoulder dislocations associated with glenoid and GT fractures are often combined with rotator cuff tears. There is a negative correlation between the size of glenoid and GT fragments, and split GT fractures are most common. Such injuries are highly correlated to the relative spatial location between the GT and the glenoid when the shoulder dislocates.

Influence of surface topography on the secondary electron yield of clean copper samples.

Secondary electron yield (SEY) due to electron impact depends strongly on surface topography. The SEY of copper samples after Ar-ion bombardment is measured in situ in a multifunctional ultrahigh vacuum system. Increasing the ion energy or duration of ion bombardment can even enlarge the SEY, though it is relatively low under moderate bombardment intensity. The results obtained with scanning electron microscopy and atomic force microscopy images demonstrate that many valley structures of original sample surfaces can be smoothed due to ion bombardment, but more hill structures are generated with stronger bombardment intensity. With increasing the surface roughness in the observed range, the maximum SEY decreases from 1.2 to 1.07 at a surface characterized by valleys, while it again increases to 1.33 at a surface spread with hills. This phenomenon indicates that hill and valley structures are respectively effective in increasing and decreasing the SEY. These obtained results thus provide a comprehensive insight into the surface topography influence on the secondary electron emission characteristics in scanning electron microscopy.

[Manipulative reduction and small splint fixation combined with micromovement exercise for treatment of humeral shaft fractures].

OBJECTIVE: To investigate the therapeutic efficacy of bone-setting manipulative reduction and small splint fixation combined with micro-movement theory exercise for treatment of humeral shaft fractures. METHODS: From March 2011 to February 2014, 64 cases of humeral shaft fractures were treated by bone-setting manipulative reduction and small splint fixation including 28 males and 36 females with an average age of 38.1 years old ranging from 22 to 67 years old. According to the classification of AO/OTA, there were 10 cases of type A1, 12 cases of type A2,11 cases of type A3,10 cases of type B1,12 cases of type B2, 7 cases of type B3, 2 cases of type C1, 1 case of type C2, 1 case of type C3. After close reduction early functional exercise performed according to micro-movement theory. All patients had no other parts of the fractures, neurovascular injury, and serious medical problems. Patients were followed up for fracture healing, shoulder and elbow joint function recovery, and curative effect. RESULTS: All patients were followed up from 10 to 12 months with an average of 10.3 months. Of them, 2 cases had a small amount of callus growth at 3 months after close reduction, so instead of operation; 2 cases appeared radial nerve symptoms after close reduction ,so instead of operation. Other patients were osseous healing, the time was 8 to 12 weeks with an average of 10.2 weeks. After osseous healing, according to Constant-Murley score system ,the average score was (93.5 ± 3.2) points, the result was excellent in 29 cases, good in 29 cases, fair in 6 cases, excellent and good rate was 90.3%; according to the Mayo score system, the average score was (93.7 ± 4.2) points, the result was excellent in 35 cases, good in 23 cases, fair in 6 cases, excellent and good rate was 91.9%. CONCLUSION: Bone-setting manipulative reduction and small splint fixation combined with micromovement theory exercise for treatment of humeral shaft fractures has advantage of positive effect, easy and inexpensive method, the treatment has relevant scientific basis and practical value, it can effectively reduce complications, promote patients early recovery.

[Cannulated screw combined with buttress plate for the treatment of transarticular shear fractures of the distal humerus].

OBJECTIVE: To investigate the clinical outcomes of cannulated screw combined with buttress plate in treating transarticular shear fractures of the distal humerus. METHODS: From July 2008 to December 2011, 17 patients with shear fractures of the distal humerus were treated with cannulated screw combined with buttress plate. Among them, included 10 males and 7 females aged from 20 to 59 years old (mean 36.5). All the fractures were classified into type I (8 cases), type II (1 case), type III (3 cases) and type IV (5 cases) according to Bryan-Morrey and McKee classification. According to AO/ASIF classification, 10 cases were type 13B3.1, 7 cases were type 13B3.3; according to Dubberley classification, 5 cases with type 1A, 2 cases with type 1B, 2 cases with type 2A, 2 cases with type 2B, 4 cases with type 3A, 2 cases with type 3B. There were 12 cases with fresh injuries, 4 cases with old injuries. All fractures were closed injuries. Complications and range of motion of elbow were observed, and clinical efficacy were evaluated by Broberg-Morrey standard. RESULTS: All patients were followed up with a mean time of 21.3 months (ranged, 18 to 24). All fractures obtained bone healing from 10 to 15 weeks with a mean of 12.5 weeks. No malunion or delayed healing occurred. Two cases occurred ossification in lateral collateral ligament attachment. 2 cases occurred heterotopic ossification in the capitellum in front of capsule joint. The range of elbow extension was (16 +/- 7) degrees, flexion was (115 +/- 9) degrees, the average are of pronation and supination was (65 +/- 5) degrees and (60 +/- 5) degrees respectively. According to Broberg-Morrey standard, there were excellent in 7 cases, good in 8 cases, fair in 2 cases, and average score was 92.44 +/- 4.64. CONCLUSION: For transarticular shear fractures of the distal humerus, classification should be performed according to preoperative X-ray and CT, cannulated screw and buttress plate combined and early function rehabilitation could recover elbow function.

[Arthroscopic surgery for the treatment of stiff elbow].

OBJECTIVE: To investigate the clinical results of arthroscopic surgery for the treatment of stiff elbow. METHODS: From October 2010 to December 2012, 27 patients with stiff elbow were treated with arthroscopic debridement and joint capsular releasing. There were 18 males and 9 females, ranging in age from 24 to 54 years old, with an average of 35.7 years old. Analgesia and rehabilitation were necessary after operation. Mayo criteria system was used to evaluate therapeutic effects. RESULTS: All the patients were followed up, and the duration ranged from 12 to 18 months, with a mean of 13.5 months. The mean maximum flexion angle of patients improved from preoperative (61.5 ± 30.1) degrees to postoperative (102.5 ± 20.1) degrees; and the mean maximum extension angle improved from preoperative (34.8 ± 12.1) degrees to postoperative (16.3 ± 16.1) degrees; the average total range of motion improved from preoperative (34.2 ± 21.0) degrees to postoperative (84.9 ± 9.2) degrees. According to the Mayo criteria system, the average score increased from preoperative 60.5 ± 13.4 to postoperative 88.7 ± 6.3; ten patients got an excellent result, 13 good and 4 fair. CONCLUSION: Arthroscopic surgery to treat elbow stiffness has such advantages as minimal invasion, less blood loss, fast recovery, and clear visualization, which is effective to improve elbow joint functions with less complications.

Heating-induced variations of secondary electron emission from ion-cleaned copper samples.

Secondary electron (SE) emission due to electron impact depends strongly on surface conditions. The variations of SE yield and spectrum with the heating temperature of Ar-ion-cleaned oxygen-free copper samples are therefore measured in situ in a multifunctional ultrahigh vacuum system. The SE yield and the SE spectrum are observed to increase and to narrow, respectively, after sample heating. The maximum SE yield increases from 0.97 before heating to 1.25 after heating at ∼313 °C, and the corresponding full width at half maximum of SE spectrum decreases considerably from 9.3 to 5.5 eV. More CO2 and Ar ions are shown to desorb at a higher heating temperature by residual gas analysis, indicating their contribution to the reduction in work function and surface potential barrier. Ar-ion desorption appears to affect the SE spectrum more than the SE yield. The obtained results provide a new insight into complicated surface influences on SE emission in thermal applications of scanning electron microscopy.

Note: measuring effects of Ar-ion cleaning on the secondary electron yield of copper due to electron impact.

In a measurement system of total secondary electron yield (SEY) with in situ ion cleaning, we investigate SEY characteristics of the Cu samples cleaned at different Ar-ion energies and cleaning time. Measured SEY data are compared with those before cleaning and simulated with the Monte Carlo method for an ideal surface of copper. We find that weakening the cleaning intensity, i.e., the ion energy or cleaning time, in some circumstances, can further reduce both the maximum SEY and the SEY at the high-energy end (>0.3 keV) of primary electrons, though the SEY is increased somewhat at the low-energy end. Accompanied by the analysis on the opposing contributions of contamination elimination and surface morphology to the SEY, this study thus provides a comprehensive insight into the effects of ion cleaning on the SEY in the investigation and suppression of secondary electron emission.