Negligible Correlation between Radiographic Measurements and Clinical Outcomes in Patients Following Primary Reverse Total Shoulder Arthroplasty
Medialized vs. lateralized humeral implant in reverse total shoulder arthroplasty: the comparison of outcomes in pseudoparalysis with massive rotator cuff tear
The lateralization and distalization shoulder angles are important determinants of clinical outcomes in reverse shoulder arthroplasty
A comprehensive evaluation of the association of radiographic measures of lateralization on clinical outcomes following reverse total shoulder arthroplasty
Recently the authors of Influence of Humeral Lengthening on Clinical Outcomes in Reverse Shoulder Arthroplasty assessed the relationship between humeral lengthening and minimal two-year clinical outcomes after RSA, pointing out that while deltoid tensioning from humeral lengthening is theorized to improve the range of motion it might also predispose patients to acromial/scapular spine fractures and neurologic injury. They studied 284 RSAs performed using a single prosthesis design (Exactech/Equinoxe).
They defined humeral lengthening as preoperative to postoperative change in the "subacromial height" (the vertical difference between the most inferolateral aspect of the acromion and the most superior aspect of the greater tuberosity).
The amount of lengthening varied through a broad range:
They found no clinically important differences between shoulders with ≤25 vs. >25 mm of lengthening with respect to ROM measures, outcome scores, or shoulder strength.
The relationship between the postoperative Simple Shoulder Test (left) and improvement in the Simple Shoulder Test (right) as a function of arm lengthening is shown below.
They noted no significant difference in the amount of humeral lengthening between patients with complications and those without complications. Patients with lengthening >25 mm did not have greater rates of acromial fracture or neurologic injury.
The authors of another recent article, Postoperative acromiohumeral interval affects shoulder range of motions following reverse total shoulder arthroplasty sought to analyze various radiographic parameters that may be predictive of clinical outcomes after RSA in 55 patients at a minimum of 2 years followup.
Radiographic parameters included critical shoulder angle, acromial index, acromiohumeral interval, deltoid lever arm, acromial angulation, glenoid version, and acromial height.
They found a very weak negative correlation between the postoperative acromiohumeral interval (see figure below) and forward flexion (r = − 0.270; p = 0.046) and internal rotation (r = 0.275; p = 0.042).
The association between postoperative acromiohumeral interval and external rotation was stronger (r = − 0.421; p = 0.001). A postoperative acromiohumeral interval less than 29 mm had an 86% positive predictive value of obtaining 130° of forward flexion and 45° of external rotation. Excessive distalization reduced forward flexion and external rotation motion of the shoulder.
However, essentially radiographic parameters were significantly associated with patient reported outcomes as seen below.
Yet another strudy, Does glenohumeral offset affect clinical outcomes in a lateralized reverse total shoulder arthroplasty? pointed out that there are at least three different RSA geometries:
Yet another strudy, Does glenohumeral offset affect clinical outcomes in a lateralized reverse total shoulder arthroplasty? pointed out that there are at least three different RSA geometries:
The authors sought to evaluate how increasing glenohumeral offset affects outcomes after RSA, specifically in a lateralized humerus - medialized glenoid implant model (right hand figure in the illustration above).
Pre- and postoperative radiographs were analyzed for measurement of glenohumeral offset, defined as the acromial-tuberosity offset (ATO) distance on the anteroposterior radiograph in 130 RSAs.
The mean postoperative absolute ATO was 16 mm, and the mean delta ATO (difference from pre- to postoperatively) was 4.6 mm further lateralized. When assessing for the effects of lateralization on patient reported outcomes, multivariate analysis failed to reveal a significant effect from the absolute postoperative ATO or the change in ATO on any outcome parameter.
For example, while the Simple Shoulder Test (SST) score improved from 4.0 to 11.0 (p<.001), the SST score was not related to change in ATO: the mean SST was 6.1 for shoulders with a change in ATO <4.6 mm and 6.3 for shoulders with a change in ATO ≥ 4.6 mm.
The authors concluded that RSA using a lateralized humerus . medialized glenoid implant exhibited excellent clinical outcomes in range of motion and patient recorded outcomes. However, the magnitude of lateralization as measured radiographically by the ATO did not significantly affect these outcomes; patients exhibited universally good outcomes irrespective of the degree of offset.
Comment: Radiographic measures have not been shown to significantly correlated with patient reported clinical outcomes of reverse total shoulder arthroplasty. This finding has three important implications:
(1) currently surgeons do not have robust evidence on which to base their positioning of reverse total shoulder components
(2) the outcomes of reverse total shoulder arthroplasty are largely influenced by factors other than component positioning
(3) clinical research directed a optimizing the clinical outcome of reverse total shoulder arthroplasty needs to include not only data on implant type and positioning, but also the characteristics of the patient (see, for example, One in three patients having shoulder arthroplasty have depression) as well as details of the preoperative condition of the shoulder.
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Here are some videos that are of shoulder interest
Shoulder arthritis - what you need to know (see this link).
How to x-ray the shoulder (see this link).
The ream and run procedure (see this link).
The total shoulder arthroplasty (see this link).
The cuff tear arthropathy arthroplasty (see this link).
The reverse total shoulder arthroplasty (see this link).
The smooth and move procedure for irreparable rotator cuff tears (see this link).
Shoulder rehabilitation exercises (see this link).
