Critical shoulder angle (CSA): age and gender distribution in the general population.

OBJECTIVE: Anatomical parameters and pathologies that can affect the critical shoulder angle (CSA) are subjects of discussion. To date, we do not know if the CSA value changes in the different decades of life in a population characterized by the same ethnicity, nor if there are differences related to gender or side. This study hypothesizes that age and gender may affect the CSA. METHODS: Patients older than 15 years old affected by a shoulder trauma and who were discharged with a diagnosis of shoulder contusion were enrolled. A true AP view of the shoulder was obtained as well as data regarding age and gender of all participants. The CSA was measured by three authors, and interoperator reliability was assessed. Eight subcategories, according to decades of life, were considered. Finally, the studied population was divided into three subcategories according to CSA values (< 30°; 30-35°; ≥ 35°). RESULTS: The initial sample comprised 3587 shoulder X-rays. The interobserver reproducibility was high, with an intraclass correlation coefficient of 0.865 (95% CI 0.793-0.915). Two thousand eight hundred seventy-three radiograms were excluded. The studied group comprised 714 patients [431 females, 283 males; mean age (SD): 47.2 (20.9) years, range: 11-93 years]. The mean CSA was 33.6° (range: 24-50°; SD: 3.9°). The mean CSA values in females and males were 33.7°and 33.5°, respectively. The mean CSA values of the right and left shoulders were 33.3° and 33.9°, respectively (p > 0.05). Linear regression analysis showed a CSA increase by 0.04° every year. The mean CSA in subjects aged between 15 and 19 years was significantly lower than all the other groups, except for patients older than 80 years. No significant differences were found between CSA subcategories, gender, or side. CONCLUSIONS: In the general population, the mean CSA value was 33.6°. No significant differences were found regarding the mean CSA value according to gender or side. A significant positive linear correlation between CSA and age was detected. In each decade of life, the CSA value, which is genetically determined, shows a large variability. LEVEL OF EVIDENCE: IV.

The Kite technique: a new all-arthroscopic technique for the treatment of acute acromioclavicular joint dislocation.

PURPOSE: Although many open techniques have been developed, no all-arthroscopic technique has been introduced to reduce acute acromioclavicular joint dislocation (ACJD) and augment both coracoclavicular (CC) ligaments. The Kite technique is the first all arthroscopic technique with this aim. METHODS: Forty-one consecutive patients [35M-6F; median: 29.2 years (range 23-36)] with acute type III and V acromioclavicular joint dislocation were treated with the Kite technique: it consists of positioning three titanium buttons connected by heavy sutures in an 8-strand configuration between clavicle and coracoid to restore the anatomy of CC ligaments. Patients were followed up for a median of 35 months (range 30-43 months). RESULTS: Median operation time was 70.6 min (range 58-82), with no cases of intra-operative complications. At the final follow-up, the median post-operative Constant Score and SST were 94.1 (range 89-98) and 11.6 (range 10-12), respectively. At the final follow-up reduction maintenance was present in 39 patients; in one patient, signs of acromioclavicular joint dislocation recurrence were present 3 months post-op. In another patient, medial suture ruptures occurred 4 months after surgery with type II acromioclavicular joint dislocation recurrence but with scarce symptoms and full recovery to sport activity. Clavicle osteolysis was observed in four patients. Cosmetics of the arm were judged as excellent in 39/41. All patients, except two, were satisfied with the final result. CONCLUSIONS: The kite technique is a safe and reproducible arthroscopic procedure to treat acute ACJD. In daily clinical practice, due to the excellent results and the low complication rate, this technique might be considered by surgeons when operative treatment of an acute acromioclavicular joint dislocation is planned. LEVEL OF EVIDENCE: IV.

Arthroscopic transosseous versus suture anchor repair: clinical outcomes in patients with bilateral rotator cuff tears.

The aim of our study was to define if Arthroscopic Transosseous Rotator Cuff Techniques should have comparable results to those of the suture-anchors technique in a single row configuration. We reported the preliminary results of a consecutive population of 22 patients who underwent a rotator cuff treatment on the left and right sides for average medium-sized thickness tears with minimal fatty infiltration with the two different techniques: transosseous rotator cuff repair technique on one side and single row with suture-anchors on the other side, in different times. Subjective evaluation with DASH questionnaires, Constant Scores and Numerical Rating Scale (NRS) for pain evaluation, have been submitted pre and postoperatively after both operations. A statistical analysis was performed to assess the superiority of one technique and to compare pre and postoperative ROM data and clinical outcomes. A transosseous rotator cuff repair was performed in 7 patients on the dominant arm, while the other 15 patients had dominant arm cuff tear lesions repaired by using suture-anchors technique. At last follow-up a significant improvement, in shoulder pain and function, was referred at both sides. Also, DASH, Constant Scores and NRS for pain evaluation improved with both techniques, but no statistical difference was found between them. Arthroscopic transosseous rotator cuff repair technique shows comparable results to those of the suture-anchors technique in a single row configuration.

Do radiolucent lines and stress shielding of the humeral shaft really matter in shoulder arthroplasty?

The purpose of this study is to evaluate at a mid-term follow up, the radiological survival of an uncemented humeral stem in shoulder arthroplasty. One hundred and twenty-six replacements including hemi (HA), total (TSA) and reverse (RSA) implanted from 1999 to 2008 were reviewed at a mean follow up of 7.2 years (48-144 months). The same uncemented triconical stem (SMR, Lima Corporate) was implanted. There were: 23 HSA, 43 TSA, 60 RSA. An independent observer evaluated all the patients with Constant Score. A radiologic analysis by an expert radiologist and an orthopaedic surgeon was performed: humeral component-bone interface was divided in seven zones. They judged a mobilisation if a migration or tilt of the humeral implant or if≥ 2 mm radiolucent line in at least three zones was present. Chi-squared test, Fisher test and analysis of variance were performed and a p<0.05 was considered statistically significant. No major radiological signs of loosening and no tilt or migration of the humeral component were found. Only 23 (18.2%) patients had no RL around the humeral implant. In the remaining 103 (81.7%) implants: 96 (76.1%) presented RL less than 2 mm, particularly 75 (59.5%) in less than 3 zones and 21 (16.6%) in more than 3 zones. Of the remaining 7 (5.5%) implants the presence of RL of 2 mm or greater in only one zone was seen. Apart from sepsis no revision was performed for humeral component loosening. Although a high rate of RL, uncemented humeral stem has an excellent survivorship at a mid-term follow up. Relationship between presence, position and depth of RL and internal stress shielding is commonly observed but does not appear to compromise quality of fixation or clinical outcomes in shoulder arthroplasty.

Rotator cuff degeneration of the healthy shoulder in patients with unilateral arm amputation is not worsened by overuse.

PURPOSE: In order to evaluate whether overuse has a significant role in rotator cuff tear (RCT) aetiology, we evaluated both shoulders of patients with old unilateral arm amputation expecting a higher rate of RC degeneration in the healthy side. METHODS: Nineteen males and six females (mean age: 57.3 ± 10.1) with an old (>20 years) unilateral arm amputation were submitted to an MRI of both shoulders. Tendon status and muscle tropism were evaluated according to Sugaya and Fuchs classifications, respectively; the acromion humeral distance was measured. Statistical analysis was performed to verify the prevalence of Sugaya and Fuchs categories in each sides. RESULTS: A significant prevalence of Sugaya type II in the amputated side (p = 0.02) and of type I in the healthy side (p < 0.001) was found. Rotator cuff was healthy in 28 and 52% of amputated and non-amputated side, respectively. The mean acromio-humeral distances of the amputated and healthy side were 0.8 cm (SD: 0.1) and 0.9 cm (SD: 0.1), respectively, (p = 0.02). A significant prevalence of Fuchs type II category in the healthy side (p < 0.001) was found. Fuchs III/IV were observed in 40 and 12% of amputated and healthy side, respectively. CONCLUSIONS: The present study resizes the role of overuse on the aetiology of RCT. Cuff tear prevalence in not amputated shoulders, inevitably submitted to functional overload, was not higher than that of coetaneous subjects with two functional upper limbs. Shoulder non-use is a risk factor for rotator cuff tear. As the prevalence of rotator cuff degeneration/tear is higher in the amputee side, non-use is a more relevant risk factor than overuse. In the daily clinical practice, patients with rotator cuff tear should be encouraged to shoulder movement because rotator cuff tendon status could be worsened by disuse. LEVEL OF EVIDENCE: III.

Acromioclavicular joint cyst in ASA 3-4 patients.Whether and how quickly it recurs after aspiration and steroid injection.

We observed the clinical course, in the short-medium term, of patients with voluminous type II acromio-clavicular (AC) joint cyst who underwent aspiration and steroid injection regarded as the only possible treatment to avoid possible skin complications. Four patients (7.4% of cases described in literature) (3F-1M ; mean age 83 years, range : 78-87 years) with a voluminous ( > 7 cm) oval, no mobile, no fluctuant cyst overlying the AC joint, were retrospectively observed. The patients, judged by the anesthesiologist as ASA 3-4 patients, were merely submitted to cyst aspiration and steroid injection. The content of the cyst was microscopically analysed. All patients were clinically evaluated on the day of aspiration and after 14-30 days and after 1 year. Shoulder function and pain intensity were analysed with Constant score and VAS. We were able to aspirate 80-150 ml of amorphous joint fluid. At the first follow-up, all patients had a recurrence of the cyst, a lower grade of tension of the skin overlying the cyst and also a very little decreasing of pain intensity. After a month from aspiration, the cysts of the 4 patients had the same size as that present before aspiration. The range of motion, the average value of VAS and Constant were similar to those recorded before aspiration. In no case signs of infection or draining sinus occurred. Aspiration is a useless practice. However it is still a motive for discussion if the reduced suffering of the skin overlying the cyst after the aspiration has avoided, or simply postponed, an imminent complication.

Arm Squeeze Test: a new clinical test to distinguish neck from shoulder pain.

PURPOSE: Objective of this study is to evaluate the diagnostic values of the Arm Squeeze Test. The test consists in squeezing the middle third of the upper arm. METHODS: 1,567 patients were included in this study. Diagnosis of cervical nerve root compression or shoulder disease was clinically formulated and confirmed with imaging before performing test. 350 healthy volunteers were recruited as controls. The test was positive when score on a VAS Scale was 3 points or higher on squeezing the middle third of the upper arm compared to acromioclavicular (AC) joint and anterolateral-subacromial area. RESULTS: Patients were subdivided as follows: 903 with rotator cuff tear, 155 with shoulder adhesive capsulitis, 101 with AC joint arthropathy, 55 with calcifying tendonitis, and 48 affected by glenohumeral arthritis. The study sample included 305 patients with cervical nerve root compression from C5 to T1 with shoulder radicular pain. The test was positive in 295/305 (96.7%) of patients with cervical nerve root compression, compared to 35/903 (3.87%), 3/155 (1.93%), 0/101 (0%), 1/55 (1.81%) and 4/48 (8.33%) of those with rotator cuff tear, adhesive capsulitis, AC arthropathy, calcifying tendonitis and glenohumeral arthritis, respectively. A positive result was obtained in 14/350 asymptomatic subjects (4%). If patients with cervical nerve root compression were compared to controls and patients with shoulder diseases, the test had sensitivity of 0.96 and specificity from 0.91 to 1. CONCLUSIONS: The Arm Squeeze Test may be useful to distinguish cervical nerve root compression from shoulder disease in case of doubtful diagnosis. A positive result to this test may lead to cervical etiology of the shoulder pain.

Glenoid version: the role of genetic and environmental factors on its variability. An MRI study on asymptomatic elderly twins.

BACKGROUND: Glenoid version is the most variable parameter of the shoulder joint. No authors investigated if intrinsic genetic factors or influences from extrinsic sources are responsible for its variability. AIM: We compared glenoid version between elderly monozygotic and dizygotic twins intending to separate the contributions of genetics from shared and unique environments. METHODS: Glenoid version of the dominant shoulder was assessed by MRI using Friedman's method in 30 pairs of elderly twins (16 monozygotic-14 dizygotic; mean age ± SD: 63.72 ± 3.37, 53-72). Heritability was estimated as twice the difference between the intraclass correlation coefficients for monozygotic and dizygotic pairs. The influence of shared environment was calculated as the difference between monozygotic correlation coefficient and the heritability index. According to job category, one way analysis of variance was used to estimate the differences between groups in the total sample and within zygosity groups. RESULTS: Glenoid version angle in monozygotic and dizygotic twins was -2° (SD: 2°) and -3° (SD: 3°), respectively (p = 0.334). Heritability index was 0.98, while the contributions of shared and unique environment were 0 and 0.02, respectively. According to working classes, no significant differences were found between the groups (p = 0.732, F = 0.31). CONCLUSIONS: Glenoid version is mainly genetically determined and only marginally influenced by environments.Level of evidence: III.

Coracoid pain test: a new clinical sign of shoulder adhesive capsulitis.

Patients with adhesive capsulitis were clinically evaluated to establish whether pain elicited by pressure on the coracoid area may be considered a pathognomonic sign of this condition. The study group included 85 patients with primary adhesive capsulitis, 465 with rotator cuff tear, 48 with calcifying tendonitis, 16 with glenohumeral arthritis, 66 with acromioclavicular arthropathy and 150 asymptomatic subjects. The test was considered positive when pain on the coracoid region was more severe than 3 points (VAS scale) with respect to the acromioclavicular joint and the anterolateral subacromial area. The test was positive in 96.4% of patients with adhesive capsulitis and in 11.1%, 14.5%, 6.2% and 10.6% of patients with the other four conditions, respectively. A positive result was obtained in 3/150 normal subjects (2%). With respect to the other four diseases, the test had a sensitivity of 0.96 and a specificity ranging from 0.87 to 0.89. With respect to controls, the sensitivity and specificity were 0.99 and 0.98, respectively. The coracoid pain test could be considered as a pathognomonic sign in physical examination of patients with stiff and painful shoulder.

Occult fractures of the greater tuberosity of the humerus.

We studied the highest reported number of patients with occult fracture of the greater tuberosity of the humerus and we analysed why fracture was not diagnosed, shoulder function and prevalence of eventually associated rotator cuff tear (RCT). Twenty-four patients with a missed fracture of the greater tuberosity underwent MR study for a suspect RCT. We evaluated shoulder function and self-assessed comfort with the Constant score (CS) and Simple Shoulder Test (SST). Nine patients showed evidence of cuff tendinosis, 11 of partial (p) RCT (2: subscapularis; 6: supraspinatus and 3: supraspinatus and infraspinatus). All patients with pRCT were older than 40. Initially, the mean CS and SST were 54% and 5/12; at follow-up, values increased to 36% and 5 points. MR should be performed in patients apparently negative for fracture but with painful shoulders and decreased ROM. Of our patients, 45.8% had pRCT; nevertheless function recovery was verified in 16 weeks.

Rotator cuff failure after surgery: an all-arthroscopic transosseous approach.

BACKGROUND: Tear recurrence is considered the main complication of a rotator cuff repair. The best arthroscopic technique has not yet been established. The aim of the present study was to evaluate, from a clinical and a radiological standpoint, the all-arthroscopic transosseous rotator cuff repair with cortical lateral augmentation, performed in the setting of a revision surgery. MATERIALS AND METHODS: Eleven consecutive cases were prospectively followed up for a minimum of 12 month after a rotator cuff repair with a novel all-arthroscopic transosseous rotator cuff repair. VAS and UCLA score and patients' satisfaction with the outcomes were analyzed, along with MRI evolution of the repair. All patients underwent a standardized surgery and postoperative rehabilitation program. RESULTS: All patients showed a significant improvement in pain reduction and functional score. Satisfaction was achieved in 10 out of 11 cases, and only 1 case showed a minor discontinuous tendon signal on the 12-month MRI assessment. No complications were noted. CONCLUSIONS: Our results favor the use of the all-arthroscopic transosseous rotator cuff revision surgery with the 2MC configuration (double MC means the initials of the authors-MM and CC, who have originally described it). It appears to be safe and effective, providing good clinical, functional, and radiological results, with a very high patient satisfaction.

Shoulder adhesive capsulitis and hypercholesterolemia: role of APO A1 lipoprotein polymorphism on etiology and severity.

PURPOSE: Relationship between shoulder adhesive capsulitis (AC) and hypercholesterolemia is known. The connecting link might be represented by the correlation between HDL and transforming growth factor beta (TGF-ß): normally, HDLs stimulate TGF-ß expression; the latter is employed in the development of fibrous tissue. We assess whether the presence of the Apo-A1-G75A-polymorphism, which is correlated to an enhanced HDL function, could be a risk factor for the genesis and severity of AC. METHODS: Peripheral blood samples of 27 patients [7M; 20F, mean age 54.81 (41-65)] with AC and hypercholesterolemia were submitted to polymerase chain reaction in order to evaluate the Apo-A1-G75A-polymorphism. Genome database was used as control. Two categories were obtained according to AC severity: type I (active forward flexion ≥ 100°) and type II (< 100°). Data were submitted to statistics. RESULTS: The prevalence of Apo-A1-G75A-polymorphism in the studied group and in the control group was 22.2% (10AG; 1AA; 16GG) and 19% (OR 1.22, IC 0.59-2.53, p > 0.05), respectively. Patients with type I and II capsulitis were 11 [flexion 148.0° (range 100°-165°)] and 16 [flexion 82.5° (range 50°-95°)], respectively. The prevalence of Apo-A1-G75A in type I was 18.1% (2AG; 9GG) and in type II was 56.3% (8GA; 1AA; 7GG), respectively (RR 1.87, IC 1.005-3.482, p < 0.05). CONCLUSIONS: Apo-A1-G75A-polymorphism is not necessary for the genesis, but it is a risk factor for severity of AC. LEVEL OF EVIDENCE: III.

Adhesive capsulitis of the shoulder: pain intensity and distribution.

PURPOSE: Papers regarding adhesive capsulitis (AC) of the shoulder focused on etiology, epidemiology, diagnosis, and treatment; until now, information on shoulder pain characteristics is still scarce. Our aim was to analyze pain intensity and distribution in patients with AC. METHODS: The study group was composed of 278 (133M-145F) consecutive patients with AC. After diagnosis, shoulder pain distribution was assessed through an upper limb pain map and pain intensity through a visual analog scale. Patients were distinguished on the basis of gender, age, time elapsed from onset of symptoms, and severity of functional limitation. Data were submitted to statistical analysis. RESULTS: Intensity of shoulder pain caused by AC was higher in females (p < 0.05); it did not vary with the side and between patient younger and older than 55 years. Patients whose pain arose from more than 3 months suffered a lower intensity of shoulder pain. Furthermore, pain intensity was higher in the most severe form of AC (active forward flexion < 60°) (p < 0.05). Pain was localized predominantly on the anterior aspect of the shoulder (dermatomes C5-C6) and rarely extended beyond the distal third of the arm. No differences were found in pain distribution between male and female, between patients with pain from less or more than 3 months and between different levels of AC severity (p > 0.05). CONCLUSION: Shoulder pain due to AC may be influenced by gender and severity of functional limitation. AC pain distribution principally involves anterior aspect of the shoulder with downward extension of the arm until its distal third. LEVELS OF EVIDENCE: Level IV.

Hertel 7 fracture of the humeral head. Can two different fixation systems (Diphos/PHP) lead to different outcomes? A retrospective study.

OBJECTIVE: To compare clinical outcomes and complication rates in the medium-to-long-term follow-up of Hertel 7 humeral head fractures treated with two different locking plates. MATERIALS AND METHODS: A total of 52 patients with type 7 humeral head fracture (in accordance with Hertel classification) were enrolled retrospectively: 24 patients [4 male, 20 female; mean age (standard deviation [SD]): 68.9 (5.8) years] were treated with Diphos H plate (Group A) and 28 patients [6 male, 22 female; mean age (SD): 61.0 (7.5) years] with Proximal Humeral Plate (PHP; Group B). The mean follow-up periods were 25.6 and 18.9 months, respectively. Functional outcomes were assessed using the Constant score and Disabilities of the Arm, Shoulder and Hand (DASH) score; X-ray evaluation was also performed and complications were recorded. RESULTS: The mean Constant score in the Diphos and PHP groups at follow-up were 75.6 (SD 13.4) and 78.9 (SD 12.8), respectively (p>0.05). The DASH score was similar in both groups (Diphos: 18.6, range 0-51.5; PHP: 16.8, range 0-47.8) (p>0.05). In our series, 9.6% of patients had complications; these included a case of aseptic non-union and a case of avascular necrosis of the humeral head in each group, and a secondary screw perforation in a patient treated with Diphos. CONCLUSIONS: In patients with Hertel 7 proximal humeral fractures, Diphos and PHP lead to similar satisfactory functional outcomes and are associated with low complication rates; this confirms that both are useful implants for the treatment of this pattern of fracture.

Anatomical variations of the trochlear notch angle: MRI analysis of 78 elbows.

BACKGROUND: Little is known about the anatomical variations of the trochlear notch angle, nor do we know whether the cartilaginous layer modifies the trochlear bony contour. Our aim was to assess the variability of the bony and cartilaginous trochlear notch angles. MATERIALS AND METHODS: We assessed 78 healthy elbows (39 patients, 19 females and 20 males) with a mean age of 28 years (range 21-32). High-definition MRI coronal scans at the level of the flexion-extension axis were performed. The cartilage thickness, the notch angle, and trochlear width were calculated at the level of the deepest point of the trochlear sulcus, the edge of the lateral and medial ridge. Patient height was used as indirect measurement of humerus length. Pearson correlation and Student's t tests were performed. RESULTS: Mean cartilage thickness was 1.00 mm (range 0.62-1.83), with significant differences between the medial trochlear ridge and the other landmarks. The notch angle ranged from 124° to 156° (mean 142°) with no differences between the bony and cartilage layers. Trochlear width ranged from 1.57 to 2.75 cm (mean 2.24) and correlated with humerus length. No correlation emerged between the trochlear notch angle, trochlear width, or humerus length. The only significant difference between sexes was the width value, with a wider trochlea in males. CONCLUSIONS: The trochlear notch angle varies considerably, determining anatomical variations in trochlear shape which ranges from less concave to more concave types. Moreover, the cartilaginous layer does not modify this angle at the level examined. These findings may be relevant to anatomical implant design for distal humerus hemiarthroplasty.

Sleep quality and disturbances in patients with different-sized rotator cuff tear.

INTRODUCTION: The literature is unanimous in saying that shoulder pain, due to rotator cuff tear (RCT), may be mostly at night; to our knowledge, this statement is not supported by scientific evidence. Our aim was to investigate sleep quality and disturbances in patient with RCT and in a control group. MATERIALS AND METHODS: A case-control design study was used. We enrolled 324 consecutive patients (Group A) (156M-168F, mean age ± SD: 64.94 ± 6.97; range 47-74) who underwent arthroscopic rotator cuff repair. Tear size was determined intraoperatively. The control group (Group B) included 184 subjects (80M-104F, mean age ± SD = 63.34 ± 6.26; range 44-75) with no RCT. All participants were submitted to two standardized self-reported questionnaires evaluating sleep quality and disturbances: the Pittsburgh Sleep Quality Index (PSQI) and the Epworth Sleepiness Scale (ESS). Data were submitted to statistics. RESULTS: We found no significant differences between the two groups according to both PSQI (Group A: 5.22 ± 2.59; Group B: 5.21 ± 2.39) and ESS (Group A: 2.59 ± 2.54; Group B: 5.76 ± 2.63), p > 0.05. Patients with small tears had average PSQI and ESS higher than patients with large and massive lesions (p < 0.005). Pearson's test showed that tear severity was negatively correlated with both sleep latency (r 2 = -0.35, ß = 0.069, p < 0.005) and sleep disturbances (r 2 = -0.65, ß = 0.053, p < 0.001). CONCLUSIONS: RCT is only one of the responsible causes for sleep disturbance in middle-aged and elderly subjects. Patients with small tears have a poorer sleep quality with respect to those with a more severe tear; particularly, they not only take more time to fall asleep, but also have a more disturbed sleep compared to patients with large and massive tears. LEVEL OF EVIDENCE: III.

Injury of the axillary nerve subsequent to recurrence of shoulder dislocation. Clinical and electromyographic study.

Injuries of the axillary nerve subsequent to recurrence of glenohumeral dislocation have received only minimal attention. It is the purpose of this study to define the prevalence and the progression in time of injury of the axillary nerve in patients with recurrence of anterior shoulder dislocation. For two years we observed a total of 185 patients who had had primary shoulder dislocation. Excluded from the study were patients who had fractures associated with metabolic disorders that favored neurologic deficit. During the period of study, 98 patients contacted us again after recurrence of the dislocation: there were 89 patients aged over 60 years and 9 aged below 60 years. All of the patients were evaluated clinically and submitted to EMG in order to verify the condition of the axillary nerve. Four patients (4%) had neuroapraxia of the axillary nerve. One of these also had neuroapraxia of the radial nerve. Of the four patients, one was a male aged 34 years; the others were all aged over 60 years. In all of the cases, function of the axillary nerve completely recovered after a mean period of 4 months (3-5.3 months) after recurrence. Injury of the axillary nerve can occur at the time of the first recurrence of the injury. However, prevalence is significantly lower than that observed after primary dislocation. The occurrence of this injury should be taken into consideration, particularly in elderly patients, in order to avoid erroneous clinical diagnosis and massive rupture of the cuff subsequent to recurrence of the dislocation.

Subacromial Space Width: Does Overuse or Genetics Play a Greater Role in Determining It? An MRI Study on Elderly Twins.

BACKGROUND: Age and peripheral microcirculation disorders are the main causes of rotator cuff degeneration. Acromion variants may affect subacromial space width, causing a pathological narrowing of the space that may compromise the cuff integrity. However, it is not clear if the subacromial space width is genetically determined or if it changes according to loading conditions. To clarify this unresolved question, we performed an MRI (magnetic resonance imaging) study with the aim of evaluating the acromiohumeral distance in a group of elderly monozygotic and dizygotic twins, and we analyzed the obtained data using the twin design to separate the contributions of shared and unique environments. METHODS: We identified twenty-nine pairs of elderly twins. On MRI scans, we evaluated the acromiohumeral distance and health status of the rotator cuff tendons. Heritability, defined as the proportion of total variance of a specific characteristic in a particular population due to a genetic cause, was estimated as twice the difference between the intraclass correlation coefficients for monozygotic and dizygotic pairs. The influence of shared environment, due to environmental factors that contribute to twin and sibling similarity, was calculated as the difference between the monozygotic correlation coefficient and the heritability index. One-way ANOVA (analysis of variance) was used to estimate the differences among job categories, both in the total cohort and within zygosity groups. RESULTS: The intraclass correlation coefficient was substantially higher for monozygotic than for dizygotic twins, indicating a high degree of concordance of the acromiohumeral distance in pairs of individuals who shared 100% of their genes. The heritability index was 0.82, and shared and unique environmental contributions were both 0.09. There were no significant differences among subjects in different job categories, either in the total cohort (p = 0.685) or within the monozygotic (p = 0.719) and dizygotic groups (p = 0.957). CONCLUSIONS: The acromiohumeral distance is mainly genetically determined and only marginally influenced by external factors.

Pedicle instrumentation in the thoracic spine. A morphometric and cadaveric study for placement of screws.

STUDY DESIGN: In part 1 of the study, the morphometry of thoracic pedicles and bony landmarks for pedicle screw placement were evaluated. In part 2, pedicle screws were inserted in fresh cadavers, using a different entry point in the left and right pedicles. OBJECTIVES: To identify the safest entry point and screw orientation for pedicle screws in the thoracic spine. SUMMARY OF BACKGROUND DATA: A few morphometric investigations have been performed on thoracic vertebrae, but the safest technique for screw insertion in thoracic pedicles has not been analyzed. METHODS: Mean, range, and standard deviations of pedicle transverse diameter and pedicle orientation were measured in 99 dried thoracic vertebrae. We evaluated the position of the bottom of the superior facet and that of the superior border of the transverse process in relation to the center of the pedicle. The relation between the pedicle axis and the superior facet in the frontal plane was also assessed. In part 2 of the study, pedicle screws were inserted in fresh cadavers at the intersection between the superior border of the transverse process and the middle of the superior facet (entry point A) and between the former and the lateral two thirds of the facet (entry point B). RESULTS: The smallest transverse diameter was found at 16 (mean 4.3 mm) where pedicles measured less than 5 mm in 68% of the specimens. In the frontal plane, the pedicle axis intersected the middle of the superior facet in 15% of specimens, the lateral two-thirds in 62%, and the lateral border of the facet in 23%. Of the 126 screws inserted in fresh human cadavers, 15 (24%) of the screws inserted using entry point A and 10 (16%) of those inserted using entry point B violated the pedicle cortex (P > 0.05). Six (10%) of the screws inserted using entry point A compared with no screw inserted using entry point B penetrated the anterior vertebral cortex (P = 0.03). CONCLUSIONS: Pedicles between T4 and T8 may not be wide enough for screw fixation. An entry point for pedicle screws located at the intersection between the superior border of the transverse process and the lateral two thirds of the superior facet seems more likely to be in line with the pedicle axis than do other entry points. In the lower thoracic vertebrae this entry point, in combination with insertion of the screws more medially oriented than the pedicle axis, significantly reduces the risk of violating the anterior vertebral cortex.

Contralateral recurrent lumbar disc herniation. Results of discectomy compared with those in primary herniation.

STUDY DESIGN: The surgical outcomes of patients who underwent discectomy for contralateral recurrent herniation and primary herniation were evaluated. OBJECTIVE: To assess whether the clinical results in patients undergoing surgery for contralateral recurrent disc herniation may be as good as those reported after primary discectomy. SUMMARY OF BACKGROUND DATA: No retrospective or prospective investigation has been conducted on the surgical treatment of contralateral recurrent lumbar disc herniation. METHODS: Sixteen patients who underwent surgery for recurrent disc herniation at the same level as primary disc excision, but on the opposite side, were analyzed prospectively from the recurrence of contralateral radicular pain (Group 1). All patients had reported a satisfactory results after primary discectomy. Fifty consecutive patients who underwent disc excision during the study period, who did not report recurrent radicular pain, were analyzed for comparison (Group 2). Overall patient satisfaction, pain severity, functional outcome, and work status were evaluated. RESULTS: At the 2-year follow-up, the clinical outcome was rated as satisfactory in 14 of 16 patients in Group 1 and in 45 of 50 in Group 2 (P > 0.05). Twelve patients in Group 1 and 42 in Group 2 had resumed their work or daily activities at the same level as before the operation (P > 0.05). Radicular pain was significantly improved in both groups at the 6-month and 2-year follow-ups. At the 6-month follow-up, low back pain was significantly improved only in the patients in Group 2; however, at the 2-year follow-up, low back pain was significantly improved in both groups. CONCLUSIONS: Clinical results in patients reoperated on for contralateral recurrent lumbar disc herniation compare favorably with those reported after primary discectomy. The improvement of pain in the low back and lower limbs reported by the majority of patients 2 years after reoperation suggests that fusion is not needed in this patient population.