Can Sufficient Internal Rotation Be Achieved with Bilateral rTSA?

Thomas Wright, MD

Read complete study: Risk of insufficient internal rotation after bilateral reverse shoulder arthroplasty: clinical and patient reported outcome in 57 patients.

This study focused on the effects and risks of bilateral reverse shoulder arthroplasty (rTSA) on internal rotation (IR) in 57 patients. Data was recorded up to two years after the second surgery. The study found that only 15 percent of patients had insufficient IR in both shoulders after 12 months and 5 percent after 24 months. Patients who had insufficient baseline IR in their second shoulder and insufficient IR 12 month post op after their first shoulder had a 100 percent risk of having insufficient IR in both shoulders. The conclusion of this article is a recommendation to use staged bilateral rTSA over the use of a hemiathroplasty. The authors found that the majority of patients would undergo the surgery again, as it does provide benefits, like reduction in pain, regardless of the issues with IR.

Literature Review:

The authors of this study focused on the risks of staged bilateral rTSA on internal rotation. I agree with their concern, as bilateral decreased IR could result in difficulties with toileting. In my practice, I stage my bilateral cases; however the timing is up to the patient. I will proceed with the second surgery no sooner than 12 weeks, but I do not recommend waiting as long as a year. In 2014, we published an article on bilateral rTSA1 in which we found all patients eventually had enough IR to allow toileting with at least one shoulder. I agree with the authors and do not recommend using a hemiarthroplasty in the second shoulder, based on the positive results that we had with rTSA.

Although the article showed a 100 percent failure rate in achieving sufficient IR in the second shoulder when it comes to patients who have both insufficient baseline IR and insufficient IR 12 months post op in their first shoulder, we have not noted that to be a problem.

One example is a 79 year old male with symptomatic cuff tear arthropathy on the right and a failed total shoulder arthroplasty (TSA) on the left due to rotator cuff insufficiency.Because of the predictable nature of performing an rTSA as a primary, the right side was addressed first. At three months post-op he had IR to L5.

Figure_1

79 year old male, cuff tear arthropathy on the right side, 3 months post op

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Patient-Specific Guides with a Custom Implant: Is This a Practical Solution?

Joseph Zuckerman, MD

Read complete study: A patient Specific guide for Optimizing custom made glenoid implantation in cases of severe glenoid defects.

These authors studied the ability to implant a custom glenoid component in 10 cadaver glenoids with glenoid defects using patient-specific guides and traditional non-guided techniques. The use of the patient-specific guide reduced angular deviations from the plan and significantly improved the position and length of the screw placements when used to implant the custom made glenoid components.

Literature Review:

The authors have focused on a well-known challenge in shoulder arthroplasty – treatment of the deformed glenoid during anatomic or reverse shoulder arthroplasty. There is no doubt that two approaches canbe developed to address this issue. The first is the use of patient-specific guides (or intraoperative positioning devices) to improve the accuracy of component placement. We all recognize that a properly placed glenoid component will have longer-term survival than a malpositioned component. The second approach is to have non-standard glenoid components available to address the deformity. These can be either custom-made implants specific for the patient being treated or augmented “off the shelf” implants that address the common deformities encountered.

I have found that using non-custom or “off the shelf” augmented glenoid components have addressed many of the bone-loss issues I have encountered.

The authors actually combine both approaches – they use a custom implant with a specimen-specific guide. This could be perceived as the “best of both” but in actuality it is quite impractical from a cost perspective. The incremental cost of a custom implant combined with a CT-generated, patient-specific guide would add significant incremental cost. In 2016, regardless of where the surgery is being performed in the world, it is a surgeon’s responsibility to consider cost, especially in the context of cost vs. potential benefit. In addition, the FDA has been very strict on the use of custom implant components, which leaves us surgeons limited options for this approach. Continue reading