Use of the fulcrum axis improves the accuracy of true anteroposterior radiographs of the shoulder

The current standard of the shoulder trauma series in Ireland - A national audit

OBJECTIVES/AIMS

The primary aim of this study was to assess the current standard of shoulder radiographs in Ireland. The secondary aim of this study was to determine whether orthopaedic surgeons in Ireland are of the opinion that a national protocol is required, and what this protocol should consist of.

METHODS

A national audit of shoulder trauma series x-rays performed in emergency departments was conducted. The number and type of views performed was recorded. The anteroposterior (AP) and axillary or Velpeau views were assessed to determine if they met pre-defined audit criteria. Consultant orthopaedic surgeons working in public trauma hospitals were invited to participate in an online survey by email.

RESULTS

The number of shoulder trauma series included in this audit was 789. The majority of patients had two views performed (75.92%, n ​= ​599) and 21.17% (n ​= ​167) had an axillary or Velpeau view. The AP view met the audit criteria in 23.09% (n ​= ​181) of cases. The survey response rate was 70.8% (n ​= ​17). 88.2% (n ​= ​15) of surgeons agreed that three views should be performed for a shoulder trauma series and 94.12% (n ​= ​16) agreed that an axillary or Velpeau view should be included. The majority of surgeons surveyed (94%, n ​= ​16) are in favour of establishing a national protocol.

CONCLUSION

The current standard shoulder trauma series in Irish hospitals consists of two views, most frequently a thoracic AP and a scapular Y view. We propose the introduction of a national protocol consisting of three views: Grashey AP, Scapular Y, and an axillary or Velpeau view.

Radiographic Severity May Not be Associated with Pain and Function in Glenohumeral Arthritis

BACKGROUND

Despite the routine use of plain radiographs to stratify the severity of glenohumeral osteoarthritis, little is known about the relationship between radiographic measures and patient-perceived pain and function.

QUESTIONS/PURPOSES

(1) What radiographic findings are associated with worse pain and function in patients with glenohumeral osteoarthritis? (2) What demographic factors are associated with worse pain and function in patients with glenohumeral osteoarthritis?

METHODS

This retrospective study included patients presenting for an initial office visit for primary glenohumeral osteoarthritis. Patients with other concurrent shoulder pathologic findings, prior surgery, lack of pain and functional scores, recent injection, or inadequate radiographs were excluded. Between January 2017 and January 2019, 3133 patients were eligible based on these inclusion criteria; 59% (1860) had outcome assessments and 48% (893) of those had radiographs. An additional 42% (378) of those with radiographs were excluded because of other shoulder findings, recent injection, prior surgery, or inadequate radiographs, leaving 16% (515 of 3133) who were fully analyzed in this study. A radiographic review included the joint space width, posterior humeral head subluxation, inferior humeral head osteophyte size, cystic change, and head asphericity. Additionally, radiographic arthritis was classified according to the Walch, Samilson-Prieto, and Kellgren-Lawrence classifications by two separate reviewers. Radiographic and demographic criteria as well as the presence of psychologic or mental illness were correlated with VAS Pain (range 1-10; minimal clinically important difference [MCID] 1.6), American Shoulder and Elbow Surgeons (ASES; range 0-100; MCID 13.6), Single Assessment Numeric Evaluation (SANE; range 0-100; MCID 14), and Simple Shoulder Test (SST; range 0-12; MCID 1.5) scores using univariate and multivariable regression analyses.

RESULTS

After accounting for age, gender, and psychologic illness in the multivariable analysis, we found that patients with Samilson-Prieto Grade 4 arthrosis had lower VAS Pain scores (β = -1.9; p = 0.02) than those with Grade 0 or 1 did; however, no clinically important associations were found between Samilson-Prieto Grade 4 and ASES (β = 7; p = 0.25), SANE (β = 4; p = 0.63), or SST (β = 0.5; p = 0.62) scores. No clinically important associations were found between Kellgren-Lawrence Grade 3 and VAS Pain (β = 1.4; p = 0.10), ASES (β = -8; p = 0.22), SANE (β = -13; p = 0.11), or SST scores (β = 0.4; p = 0.66). Radiographic joint space and posterior subluxation also did not have any clinically important associations with VAS Pain or functional scores. In assessing Walch glenoid type, there was no clinically important association between glenoid type and VAS Pain (F = 3.1; p < 0.01), ASES (F = 1.9; p = 0.15), SANE (F = 0.45; p = 0.66), or SST scores (F = 0.76; p = 0.71). Men had higher SST scores than women did (β = 2.0; p < 0.01), but there were no clinically important differences in VAS Pain (β = -0.4; p = 0.04), ASES (β = 6; p < 0.01), or SANE (β = 4; p = 0.07) scores. No clinically important association was found between age or the presence of any psychologic illness and VAS Pain or functional scores.

CONCLUSION

In patients with glenohumeral arthritis, no consistent clinically important differences in pain or function were discovered with respect to radiographic or demographic factors. Surgeons should understand that the pain levels of patients with glenohumeral arthritis may not parallel radiographic severity. Future studies can build on these findings by examining other non-radiographic or demographic factors that affect pain in patients with shoulder arthritis, such as psychological factors.

LEVEL OF EVIDENCE

Level III, prognostic study.

The fulcrum axis: an accurate measure of glenoid version on radiographs and computed tomography

BACKGROUND

Proper glenoid position in total shoulder arthroplasty (TSA) is important. However, traditional glenoid version (GV) measurements overestimate retroversion on radiographs (XR) and computed tomography (CT).The fulcrum axis (FA) uses palpable surface landmarks and may be useful as an intra-operative guide. Also, the FA has not yet been validated on XR or CT in an arthritic population.

METHODS

Four observers measured FA and GV on the XR, CT and three-dimensional CT (3DCT) of 40 patients who underwent TSA at a single institution from 2009 to 2015. Reliability and accuracy of FA and GV were calculated for XR and CT, using 3DCT as the gold standard.

RESULTS

The mean FA and GV were 7.768° and 18.910° on XR; 6.23° and 12.920° on CT; and 8.100° and 7.740° on 3DCT, respectively. FA and GV were significantly different for XR and CT (p < 0.001) but not for 3DCT (p = 0.725). The inter-rater reliability, intra-rater reliability and accuracy of FA were not significantly different from GV and were 0.929 to 0.948, 0.779 to 0.974 and 0.674 to 0.705, respectively. However, the absolute difference of FA was closer to the gold standard (3DCT) than GV for XR (0.330° versus 11.172°) and CT (1.871° versus 5.178°) (p < 0.001).

CONCLUSIONS

FA showed comparable reliability and accuracy to GV. However, FA more accurately reflected the gold standard.

Relationship of Intraoperative Anatomical Landmarks, the Scapular Plane and the Perpendicular Plane with Glenoid for Central Guide Insertion during Shoulder Arthroplasty

Background

This study was undertaken to evaluate the positional relationship between planes of the glenoid component (the scapular plane and the perpendicular plane to the glenoid) and its surrounding structures.

Methods

Computed tomography (CT) images of both shoulders of 100 patients were evaluated using the 3-dimensional CT reconstruction program (Aquarius^®; TeraRecon). We determined the most lateral scapular bony structure of the scapular plane and measured the shortest distance between the anterolateral corner of the acromion and the scapular plane. The distance between the scapular plane and the midpoint of the line connecting the posterolateral corner of acromion and the anterior tip of the coracoid process (fulcrum axis) was also evaluated. The perpendicular plane was then adjusted to the glenoid and the same values were re-assessed.

Results

The acromion was the most lateral scapular structure of scapular plane and perpendicular plane to the glenoid. The average distance from the anterolateral corner of the acromion to the scapular plane was 10.44 ± 5.11 mm, and to the plane perpendicular to the glenoid was 9.55 ± 5.13 mm. The midpoint of fulcrum axis was positioned towards the acromion and was measured at 3.90 ± 3.21 mm from the scapular plane and at 3.84 ± 3.17 mm from the perpendicular plane to the glenoid.

Conclusions

Our data indicates that the relationship between the perpendicular plane to the glenoid plane and its surrounding structures is reliable and can be used as guidelines during glenoid component insertion (level of evidence: Level IV, case series, treatment study).

Improving the diagnostic quality and adequacy of shoulder radiographs in a District General Hospital

A high rate of suboptimal shoulder radiographs was identified during a service evaluation exercise in our orthopaedic outpatient clinics. Inadequate radiographs require a return to the radiology department for further imaging, a resultant increased workload, delays in the clinic, increased radiation for patients, and inconvenience and decreased patient satisfaction. Furthermore, if a sub-optimal radiograph is accepted there is concern that diagnoses may be missed. The aim of this project was to decrease the rate of suboptimal radiographs by delivering a teaching package directed towards quality improvement.

Evaluation criteria were set for standard orthopaedic shoulder radiographs (Anterior-posterior, axillary, and Velpeau views). Baseline data collection was performed over three, two-week periods and included all patients attending the shoulder clinic. The percentage of x-rays which were deemed adequate was only 19.4% for anterior-posterior views and 57.9% for axillary views.

A comprehensive educational package was delivered to radiographers. This included a formal PowerPoint based teaching session, hands on training with practice using a skeleton, posters with step-by step instructions on how to obtain an adequate image, and PDF aide memoires suitable for viewing on a smartphone. Two subsequent two-week periods of data collection were performed to evaluate the benefit of this intervention.

Delivery of focussed training and provision of easily accessible aide memoires to facilitate improved quality of radiographs resulted in a significant (p<0.05) reduction in the rate of inadequate images. There was also a significant decreases in the rate of return to the radiology department for repeat imaging.

Computerized 3D morphological analysis of glenoid orientation

An accurate preoperative measurement of glenoid orientation is crucial for evaluating pathologies and successful total shoulder arthroplasty. Existing methods may be labor-intensive, observer-dependent, and sensitive to the misalignment between the scapula plane and CT scanning direction. In this study, we proposed a computation framework and performed an automated analysis of the glenoid orientation based on 3D surface data. Three-dimensional models of 12 scapulae were analyzed. The glenoid cavity and external anatomical features were automatically extracted from these 3D models. Glenoid version was calculated using the scapula plane and the fulcrum axis alternatively. Glenoid inclination was measured both relative to transverse axis of the scapula and the medial pole-inferior tip axis. The mean (±SD) of the fulcrum-based glenoid version was -0.55° (±4.17°), while the scapular-plane-based glenoid version was -5.05° (±3.50°). The mean (±SD) of glenoid inclinations based on the medial pole and inferior tip was 12.75° (±5.03°) while the mean (±SD) of the glenoid inclination based on the medial pole and glenoid center was 4.63° (±4.86°). Our computational framework was able to extract the reproducible morphological measures free of inter- and intra- observer variability. For the first time in 3D, we showed that the fulcrum axis was practically perpendicular to the glenoid plane normal (radial line), and thus extended the fulcrum-based glenoid version for quantifying 3D glenoid orientation.

Vacuum assist glenoid fixation: does this technique lead to a more durable glenoid component?

INTRODUCTION

This was a prospective random study to determine if suction applied to the glenoid vault through the coracoid process would facilitate deeper penetration of cement into the vault, and if deeper penetration would lead to a more durable glenoid component.

MATERIALS AND METHODS

A group of 96 patients were randomly assigned to 1 of 2 pathways for glenoid fixation. One was cemented using modern "third generation" cementing techniques, while the second group utilizes these same steps as well as a vacuum assist (weep-hole) technique. We measured the "amount" of cement that penetrated the vault around either a pegged or keeled component as a function of the area of the cement noted on the fluoroscopic AP film that was taken 35.1 months postoperatively. We were able to determine the area of this irregular shape by using a program that was specifically written for the study. The films were evaluated by the senior author, as well as 2 musculoskeletal trained radiologists blind to the technique.

RESULTS

The area of the cement mantle was found to be significantly larger (P < .005) in the group with the vacuum assist technique. There was a positive relationship between the durability of the cement mantle as determined by the presence and the extent of radiolucent lines and the size of the cement mantle (P < .001).

CONCLUSION

If a cement technique is chosen to implant a glenoid component, the vacuum assist weep-hole technique is the most effective cementing technique to achieve durable fixation.