Monday, February 4, 2019

Outcomes of arthroscopic rotator cuff repairs

Establishing clinically significant outcome after arthroscopic rotator cuff repair

These authors assessed the minimal clinical important difference (MCID), substantial clinical benefit (SCB), and patient acceptable symptomatic state (PASS) for 288 patients having cuff repairs using the  American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), Single Assessment Numeric Evaluation (SANE), and Constant-Murley (Constant) scores preoperatively and 1 year postoperatively

The MCID, SCB, and PASS were, respectively, 11.1, 17.5, and 86.7 for ASES, 4.6, 5.5, and 23.3 for the Constant score, and 16.9, 29.8, and 82.5 for the SANE score. 

Factors such as current smoking, type of repair, Workers’ compensation, and preoperative were inconsistently associated with these outcomes.

Comment: This study did not include two important determinants of the outcome from cuff repair surgery: the size of the cuff tear and the integrity of the cuff at followup.

While there are many approaches to outcome measurement, one that is easy for surgeons to use and patients to understand is the percent of maximum possible improvement (%MPI) as explained here:

Determining the minimal clinically important difference for the American Shoulder and Elbow Surgeons score, Simple Shoulder Test, and visual analog scale measuring pain after shoulder arthroplasty.

Primary anatomic total shoulder arthroplasty (TSA), primary reverse TSA, or hemiarthroplasty was performed in 326 patients. The SST score, ASES score, and VAS pain score were collected preoperatively and at a minimum of 2 years postoperatively (mean, 3.5 years).

The minimal clinically important differences (MCIDs) were calculated for the ASES score, SST score, and VAS pain score using a 4-item anchor question evaluating improvement after treatment. Patients were asked the following: “Since your shoulder replacement surgery, please rate your response to treatment: A, none—no good at all, ineffective treatment; B, poor—some effect but unsatisfactory; C, good—satisfactory effect with occasional episodes of pain or stiffness; D, excellent—ideal response, virtually pain free.” Patients were classified by the anchor question as having “no change” (A group [none] and B group [poor] combined) or “change” (C group [good]). The D group (excellent) was not included in the analysis because this was considered beyond minimal change.

The MCIDs for the ASES score, SST score, and VAS pain score were 20.9 (P < .001), 2.4 (P < .0001), and 1.4 (P = .0158), respectively. 

Duration of follow-up and type of arthroplasty (anatomic TSA vs reverse TSA) did not have a significant effect on the MCIDs (P > .1) except shorter follow-up correlated with a larger MCID for the ASES score (P = .0081). 

Younger age correlated with larger MCIDs for all scores (P < .024). Female sex correlated with larger MCIDs for the VAS pain score (P = .123) and ASES score (P = .05).

Patients treated with a shoulder arthroplasty require a 1.4-point improvement in the VAS pain score, a 2.4-point improvement in the SST score, and a 21-point improvement in the ASES score to achieve a minimal clinical importance difference from the procedure.


Comment: MCID is one way of looking at the amount of improvement, but it has a problem. Consider two patient having a shoulder arthroplasty, each with an improvement of 3 in the SST score (both exceeding the 2.4 MCID improvement).




Their outcomes are not the same. For that reason we use both the preoperative to postoperative change in the SST as well as the percent of maximal possible improvement to characterize the result:


Here we can see that Smith only improved by 27% of the maximal possible improvement, whereas Jones improved by 75% of the maximal possible improvement (even though the improvement in both cases exceeded the MCID).

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.

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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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