Revision with a Platform System

Alberto Rivera, MD

Read complete studies:

Conversion to reverse shoulder arthroplasty: humeral stem retention versus revision

Platform shoulder arthroplasty: a systematic review

The number of shoulder arthroplasty procedures is rapidly increasing. Therefore, shoulder revision is becoming a commonly performed procedure. Historically revising a hemiarthroplasty or total shoulder replacement ended up in a hemiarthoplasty, resection arthroplasty, arthrodesis or more recently reverse arthroplasty. This type of revision usually required stem removal, which could potentially lead to humeral fracture with or without the need of an osteotomy, increasing surgical time, bleeding and neural damage.  Also, late complications, such as osteotomy nonunion and malunion could develop. Another important factor to take into consideration is the added cost of using additional implants such as a new stem, cement, cables or allograft in the setting of humeral stem revision. Modular implants using a platform system allows for a faster revision with fewer complications and potentially less cost.

“Recent publication by Williams and Colleagues (1) reported on 17 patients who underwent modular conversion and nine who had revision of humeral stem. Pain, stability and ASES scores improved significantly.”

I believe the use of modular platform in primary shoulder arthroplasty either hemi or total should be the standard of care.

In my experience, revising TSA to RSA has evolved to a more straightforward procedure with the use of modular components of the platform shoulder type. I believe the use of modular platform in primary shoulder arthroplasty either hemi or total should be the standard of care.

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How Can We Improve Accuracy in TSA?

Ian Byram, MD

Read complete study: Comparison of patient-specific instruments with standard surgical instruments in determining glenoid component position: a randomized prospective clinical trial

The authors of this randomized clinical study compared 15 anatomic total shoulder arthroplasties performed with patient-specific instrumentation to 16 aTSA cases performed with standard surgical instrumentation.  Preoperative three-dimensional CT scan images were utilized in both groups to plan the desired implant position, then postoperative CT scans were performed to measure the differences between the intended and actual glenoid implant position.  The authors reported improved accuracy of the PSI group with statistically significant decreases in mean deviation of inclination and medial-lateral offset as compared to the standard group. Mean deviation in version was 4.3° ± 4.5° for the PSI group as compared to 6.9° ± 4.4° in the standard surgical group (p=0.11), with significant improvement in version accuracy in patients with preoperative retroversion in excess of 16°. The authors conclude that surgical accuracy is improved by patient specific instrumentation when compared to standard surgical instrumentation, with greatest benefit occurring in patients with severe glenoid deformity.

As technology continues to progress, we will have increased opportunities to improve surgical accuracy in shoulder arthroplasty implant positioning.  These are exciting times, but it is our duty to balance cost and utility with progress.  The current study brings up several interesting points that impact my practice:

  1. Preoperative planning with three-dimensional imaging has greatly improved our knowledge and performance in glenoid implant positioning
  2. Intraoperative instrumentation and/or guidance does improve accuracy
  3. The desired correction of retroversion remains undetermined

By preoperatively templating, I can more reliably enact a surgical plan to meet the needs of my patients, and this should be considered standard of care in shoulder arthroplasty.

Regarding preoperative planning, I routinely obtain preoperative CT scans with three dimensional reconstructions on nearly all shoulder arthroplasty candidates.  The arthritic glenoid does not wear in two dimensions but often with subtle variations that may not be obvious on axillary radiographs or even axial CT cuts alone.  By preoperatively templating, I can more reliably enact a surgical plan to meet the needs of my patients, and this should be considered standard of care in shoulder arthroplasty. In patients with a central wear pattern that have already obtained an MRI to assess the integrity of the rotator cuff I will consider planning based on this study alone, but this is generally only for cost purposes or patient convenience.

With regard to the second point, this study shows how intraoperative guidance can improve accuracy in glenoid positioning, with the greatest benefit seen in patients with severe deformity.  It has been shown numerous times that anatomic placement of implants leads to improved clinical outcomes in shoulder arthroplasty. Intraoperative guidance can be in the form of PSI (as seen in this study), custom implants, or computer guided intraoperative navigation.  In my practice, I have begun to implement CT guided navigation for glenoid implantation.  PSI and computer navigation both offer the ability to improve accuracy, but PSI does not allow for intraoperative corrections such as conversion to reverse arthroplasty or difficulty applying the PSI guide due to anatomical constraints.  In this study, 3 of the 44 patients initially enrolled for anatomic TSA underwent reverse TSA, eliminating them as candidates for PSI.

As an example, the following case is a 67 year old male with a retroverted glenoid and intact rotator cuff based on exam and preoperative imaging.

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How Effective is Vancomycin for Preventing Infections after TSA?

Tom Wright, MD

Read complete study: The cost effectiveness of vancomycin for preventing infections after shoulder arthroplasty: a break-even analysis

Surgical site infection is one of the most common and expensive post-operative complications to manage in shoulder arthroplasty. The combination of increased methicillin resistance and decreased efficacy of IV cephlasporins, and Propionibacterium acnes  infections , has led shoulder specialists to look for other methods to prophylax against infections in shoulder arthroplasty. Primary shoulder arthroplasty infection rates have been reported from 0-4%, and with revision arthroplasty, the rates are higher, occurring from 4-15% of the time. Although these rates are low, an infection in a shoulder arthroplasty has devastating effects on the patient and is extremely expensive. Surgical site infection accounts for 22% of all health care related infection costs estimated from $1-10 billion annually.

The authors in this article have been using vancomycin powder in the wound bed before closing the surgical site. The authors have looked at the reports from spine surgeries that have shown significant reduction in infection rates when comparing non-vancomycin treatment vs. vancomycin treatment. Based on this information, they have been using vancomycin powder in their shoulder operations since 2013. As with all things in our current health care system, any increase in cost must be justified, and this paper aims at looking at the cost effectiveness of treating patients preemptively with vancomycin powder in the local wound site. They looked at the average cost of 16 patients being treated for infection and quantified the stages of treatment and cost at each stage. The general standard of care for an infected shoulder arthroplasty for patients is as follows:

  1. Arthroscopic biopsy/aspiration
  2. Resection arthroplasty/ Antibiotic impregnated spacer
  3. PICC/Home care for 6 weeks
  4. Repeat biopsy
  5. Revision reverse shoulder arthroplasty

This treatment protocol for these 16 patients averaged $46,744.54 per patient. At the same facility a 1000mg bottle of vancomycin cost $17.15. Based on these data points, the analysis showed that the treatment with vancomycin powder needed to only reduce infection by .04% to be deemed cost effective (break-even).

My practice in a University setting tends to have a large referral base for revisions, which carries a higher infection rate. Because of this high-risk patient population (revision shoulder arthroplasty) and the significant resistance to cephlosporins, it caused me to review the spine literature.

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Does Post-op Protocol Affect Function and Pain After TSA?

Felix  Savoie, MD

Read complete study: Immediate versus delayed passive range of motion following total shoulder arthroplasty 

A recent article from Denard and Ladermann looked at the difference in ROM, VAS pain scores and ASES scores between differing post-op protocols of immediate motion and delayed motion.

The immediate motion group wore a sling for four weeks following surgeries; passive forward flexion and passive external rotation of the shoulder joint was started on day one post-op. Active hand, wrist and elbow exercise and active scapular retraction were allowed immediately as well. At four weeks, the sling was discontinued and passive external rotation was allowed as tolerated. Strengthening was initiated routinely at eight weeks post-op.

In the delayed motion group, a sling was worn for four weeks following surgery. During these four weeks, patients only performed active hand, wrist and elbow exercises, as well as scapular retraction exercises. At four weeks, the sling was discontinued and passive forward elevation and external rotation was allowed as tolerated. At eight weeks pot-op, active assisted progression to active ROM was allowed and strengthening was routinely started. Activities were allowed as tolerated at 16 weeks post-op with a lifetime recommendation of no overhead lifting of 25lbs or more.

The findings of the article showed that at one year post-op there was no difference between the two groups in ROM, ASES and VAS pain. An interesting finding in this paper was that the immediate motion group had a higher failure rate of the tuberosity osteotomy used to repair the subscapularis. The authors point out that immediate motion group saw initial improvements in ROM, but after three months both groups had relatively the same ROM. The benefit of early motion may not outweigh the risk of the subscap failure, which in my opinion, is a major risk of total shoulder arthroplasty.

I also employ a subscapularis sparing technique on high-demand younger patients where early motion is achievable and risk to the subscapularis is minimal.

My current post-op protocol is to protect the subscapularis for approximately six weeks if I have to detach it. I usually use a thin LT osteotomy,  but I also employ a subscapularis sparing technique on high-demand younger patients where early motion is achievable and risk to the subscapularis is minimal. The technique uses a modified technique through the delto-pectoral approach approximately 50 percent of the inferior subscapularis is taken down while keeping the top 50 percent attached.

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