Friday, November 30, 2018

Total shoulder clinical outcome assessment made simple = percent of maximal possible improvement in the SST or ASES score

Predicting outstanding results after anatomic total shoulder arthroplasty using percentage of maximal outcome improvement

These authors sought to determine the percentage of maximal improvement in the Simple Shoulder Test (SST) or American Shoulder and Elbow Surgeons (ASES) score associated with “excellent” patient satisfaction after total shoulder arthroplasty (TSA).

For 301 and 319 patients with at least 2 years’ follow-up for the SST score and ASES score, respectively, they used receiver operating curve analysis to determine that 72.1% of maximal improvement in the SST score and 75.6% of maximal improvement were the thresholds for excellent satisfaction.

Comment: This article is most reassuring. First of all it supports the concept that use of the percent maximal possible improvement renders similar results for different outcome scoring systems. In their study improvement of 70-76% of the maximal possible improvement was associated with an "excellent" clinical outcome whether the Simple Shoulder Test or the ASES score was used. 

Second, The SST scores improved from 27% to 77% of the maximum score of 12; similarly,  the ASES improved from 31% to 81% of the maximum score of 100.

Third, the distribution of preoperative SST scores for total shoulder patients in this paper 

was virtually identical to that for total shoulders (shown in green below) in a recent paper from a different group of surgeons writing on the "Tipping Point" for surgery (see this link).

The average SST score before total shoulder arthroplasty for patients in both centers was 3.

Thus there is reassuring consistency in the results for different patient reported outcome scales and in the results between different centers.

Here's another related post showing the consistency among outcome scales:

Establishing maximal medical improvement after anatomic total shoulder arthroplasty 

These authors conducted a systematic review  of 13 studies reporting sequential followup of 984 patients at several time points, up to a minimum of 2 years after total shoulder. Assessment for clinically significant improvements between time intervals was made by using the minimal clinically important difference specific to each patient-reported outcome measure.

Clinically significant improvements in patient-reported outcome scores were noted up to 1 year following TSA, but no further clinical significance was seen from 1 year to 2 years.

For both the subjective and objective outcomes, the majority of improvements occurred in the first 3 months after the procedure.

These authors found similar results for reverse total shoulders as shown in this link.

Comment: It is of interest and importance that the Simple Shoulder Test results of our recent, currently unpublished 11 international center study including 1270 patients receiving anatomic total shoulders with a standard (non-augmented) all polyethylene glenoid component (shown below):  

are virtually identical to the Simple Shoulder Test results from this systematic review (shown below):

It also of interest that in this systematic review, the normalized outcomes are essentially independent of the patient reported outcome scale used:

Thus measuring the outcomes of shoulder arthroplasty can be simplified: (1) any of the validated patient reported scoring systems can be used and (2) the one year results are as good as the two year year results (the "standard" requirement for 2 year followup may not be necessary for TSAs). In order for new total shoulder systems to demonstrate that they offer increased value over current approaches, their one year outcomes need to exceed those shown here.

We can conclude that most of the common outcome scores yield similar results and that the percent of maximal possible improvement provides an easy way for patients and surgeons to understand the results.

We have a new set of shoulder youtubes about the shoulder, check them out at this link.

Be sure to visit "Ream and Run - the state of the art" regarding this radically conservative approach to shoulder arthritis at this link and this link

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