Preoperative factors associated with loss of range of motion after reverse shoulder arthroplasty

Current Role of Reverse Total Shoulder Arthroplasty in the Management of Glenohumeral Osteoarthritis

Reverse total shoulder arthroplasty (RSA) was historically reserved for the elderly, low-demand patient with rotator cuff arthropathy (RCA) or as a salvage procedure after failed primary arthroplasty. Surgeon expertise and the advancement of implant design has allowed RSA to now become commonplace not only for RCA but also for glenohumeral osteoarthritis. RSA provides a robust glenoid baseplate fixation, which allows for easier and more reliable bone grafting or augmentation when needed. For patients with severe glenoid bone loss, RSA has been shown to have superior or equivalent patient-reported outcomes and shoulder range of motion when compared with total shoulder arthroplasty.

Outcomes and complications of revision reverse shoulder arthroplasty after failed primary anatomic shoulder arthroplasty or hemiarthroplasty: a systematic review

BACKGROUND

The purpose of this study is to systematically review the evidence in the literature to ascertain the functional outcomes, range of motion (ROM), and complication and reoperation rates after revision reverse shoulder arthroplasty (RSA) for a failed primary total shoulder arthroplasty (TSA) or hemiarthroplasty (HA).

METHODS

Two independent reviewers performed the literature search based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines using the EMBASE, MEDLINE, and The Cochrane Library databases. Studies were included if they reported clinical outcomes for revision RSA for a failed primary TSA or HA.

RESULTS

Our review found 23 studies including 1041 shoulders (627 TSA and 414 HA) meeting our inclusion criteria. The majority of patients were female (66.1%), with an average age of 69.0 years (range: 39-93 years) and a mean follow-up of 46.3 months. American Shoulder and Elbow Surgeons and visual analog scale pain scores improved from 32.6 to 61.9 and 6.7 to 2.7, respectively. ROM results include forward flexion, abduction, and external rotation, which improved from 59.4° to 107.7°, 50.7° to 104.4°, and 19.8° to 26.3°, respectively. Only 1 of the 10 studies reporting internal rotation found a statistically significant difference, with the mean internal rotation improving from S1-S3 preoperatively to L4-L5 postoperatively for patients undergoing HA. The overall complication rate and reoperation rate were 23.4% and 12.5%, respectively. The most common complications were glenoid component loosening (6.0%), fracture (periprosthetic, intraoperative, or other scapula fractures) (n = 4.7%), and infection (n = 3.3%).

CONCLUSIONS

Revision RSA for a failed primary TSA and HA has been shown to result in excellent functional outcomes and improved ROM, suggesting that patients who have failed TSA or HA may benefit from a revision RSA.

Posteroinferior glenosphere positioning is associated with improved range of motion following reverse shoulder arthroplasty with a 135° inlay humeral component and lateralized glenoid

BACKGROUND

Optimal glenosphere positioning in a lateralized reverse shoulder arthroplasty (RSA) to maximize functional outcomes has yet to be clearly defined. Center of rotation (COR) measurements have largely relied on anteroposterior radiographs, which allow assessment of lateralization and inferior position, but ignore scapular Y radiographs, which may provide an assessment of the posterior and inferior position relative to the acromion. The purpose of this study was to evaluate the COR in the sagittal plane and assess the effect of glenosphere positioning with functional outcomes using a 135° inlay stem with a lateralized glenoid.

METHODS

A retrospective review was performed on a prospectively maintained multicenter database on patients who underwent primary RSA from 2015 to 2021 with a 135° inlay stem. The COR was measured on minimum 2-year postoperative sagittal plain radiographs using a best-fit circle fit method. A best-fit circle was made on the glenosphere and the center was marked. From there, 4 measurements were made: (1) center to the inner cortex of the coracoid, (2) center to the inner cortex of the anterior acromion, (3) center to the inner cortex of the middle acromion, and (4) center to the inner cortex of the posterior acromion. Regression analysis was performed to evaluate any association between the position of the COR relative to bony landmarks with functional outcomes.

RESULTS

A total of 136 RSAs met the study criteria. There was no relation with any of the distances with outcome scores (American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form, visual analog scale). In regard to range of motion (ROM), each distance had an effect on at least 1 parameter. The COR to coracoid distance had the broadest association with ROM, with improvements in forward flexion (FF), external rotation (ER0), and internal rotation with the arm at 90° (IR90) (P < .001, P = .031, and P < .001, respectively). The COR to coracoid distance was also the only distance to affect the final FF and IR90. For every 1-mm increase in this distance, there was a 1.8° increase in FF and 1.5° increase in IR90 (β = 1.78, 95% confidence interval [CI] 0.85-2.72, P < .001, and β = 1.53, 95% CI 0.65-2.41, P < .001; respectively).

CONCLUSION

Evaluation of the COR following RSA in the sagittal plane suggests that a posteroinferior glenosphere position may improve ROM when using a 135° inlay humeral component and a lateralized glenoid.

Predictive factors influencing internal rotation following reverse total shoulder arthroplasty

BACKGROUND

Reverse total shoulder arthroplasty (RTSA) is increasingly used as a treatment modality for various pathologies. The purpose of this review is to identify preoperative risk factors associated with loss of internal rotation (IR) after RTSA.

METHODS

A systematic review was conducted using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Ovid MEDLINE, Ovid Embase, and Scopus were queried. The inclusion criteria were as follows: articles in English language, minimum 1-year follow-up postoperatively, study published after 2012, a minimum of 10 patients in a series, RTSA surgery for any indication, and explicitly reported IR. The exclusion criteria were as follows: articles whose full text was unavailable or that were unable to be translated to English language, a follow-up of less than 1 year, case reports or series of less than 10 cases, review articles, studies in which tendon transfers were performed at the time of surgery, procedures that were not RTSA, and studies in which the range of motion in IR was not reported.

RESULTS

The search yielded 3792 titles, and 1497 duplicate records were removed before screening. Ultimately, 16 studies met the inclusion criteria with a total of 5124 patients who underwent RTSA. Three studies found that poor preoperative functional IR served as a significant risk factor for poor postoperative IR. Eight studies addressed the impact of subscapularis, with 4 reporting no difference in IR based on subscapularis repair and 4 reporting significant improvements with subscapularis repair. Among studies with sufficient power, BMI was found to be inversely correlated with degree of IR after RTSA. Preoperative opioid use was found to negatively affect IR. Other studies showed that glenoid retroversion, component lateralization, and individualized component positioning affected postoperative IR.

CONCLUSIONS

This study found that preoperative IR, individualized implant version, preoperative opioid use, increased body mass index and increased glenoid lateralization were all found to have a significant impact on IR after RTSA. Studies that analyzed the impact of subscapularis repair reported conflicting results.

The influence of preoperative rotator cuff cross-sectional area and strength on postoperative outcomes in reverse shoulder arthroplasty

BACKGROUND

Although preoperative function and range of motion (ROM) are determinants of postoperative outcome following reverse shoulder arthroplasty (RSA), there is limited data on the influence of preoperative rotator cuff status. The purpose of this study was to evaluate the relationship between preoperative rotator cuff physiologic cross-sectional area (PCSA) and strength on postoperative RSA outcome.

METHODS

A retrospective review was conducted on 53 primary RSAs from a multicenter database performed between 2015 and 2019 using a 135° humeral neck-shaft angle. Preoperative magnetic resonance imaging and computed tomographic scans were used to assess the PCSA of the subscapularis, supraspinatus, infraspinatus, and teres minor. American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) scores, ROM, and strength were measured preoperatively and at a minimum of 2 years postoperatively. Correlation coefficients were used to determine the relationship between variables.

RESULTS

There were no significant correlations between preoperative PCSA of any rotator cuff muscles and postoperative ASES scores. Preoperative subscapularis PCSA positively correlated with change in belly press (BP) strength following RSA (⍴ = 0.37, P = .006). Preoperative abduction strength was significantly correlated with postoperative abduction strength (⍴ = 0.297, P = .006). Preoperative external rotation (ER) strength was significantly correlated with postoperative ER (⍴ = 0.378, P = .005) and abduction (⍴ = 0.304; P = .032) strength. Preoperative BP strength negatively correlated with postoperative ASES (⍴ = -0.283, P = .042) but positively correlated with postoperative BP (⍴ = 0.411, P = .001) and abduction (⍴ = 0.367, P = .009) strength.

CONCLUSION

With the use of a 135° humeral implant, there is limited correlation between preoperative PCSA and postoperative outcomes 2 years following RSA; the only significant correlation was between preoperative subscapularis PCSA and postoperative BP strength. Preoperative strength is positively correlated with postoperative strength but not ROM or ASES scores.

Using machine learning to predict internal rotation after anatomic and reverse total shoulder arthroplasty

BACKGROUND

Improvement in internal rotation (IR) after anatomic (aTSA) and reverse (rTSA) total shoulder arthroplasty is difficult to predict, with rTSA patients experiencing greater variability and more limited IR improvements than aTSA patients. The purpose of this study is to quantify and compare the IR score for aTSA and rTSA patients and create supervised machine learning that predicts IR after aTSA and rTSA at multiple postoperative time points.

METHODS

Clinical data from 2270 aTSA and 4198 rTSA patients were analyzed using 3 supervised machine learning techniques to create predictive models for internal rotation as measured by the IR score at 6 postoperative time points. Predictions were performed using the full input feature set and 2 minimal input feature sets. The mean absolute error (MAE) quantified the difference between actual and predicted IR scores for each model at each time point. The predictive accuracy of the XGBoost algorithm was also quantified by its ability to distinguish which patients would achieve clinical improvement greater than the minimal clinically important difference (MCID) and substantial clinical benefit (SCB) patient satisfaction thresholds for IR score at 2-3 years after surgery.

RESULTS

rTSA patients had significantly lower mean IR scores and significantly less mean IR score improvement than aTSA patients at each postoperative time point. Both aTSA and rTSA patients experienced significant improvements in their ability to perform activities of daily living (ADLs); however, aTSA patients were significantly more likely to perform these ADLs. Using a minimal feature set of preoperative inputs, our machine learning algorithms had equivalent accuracy when predicting IR score for both aTSA (0.92-1.18 MAE) and rTSA (1.03-1.25 MAE) from 3 months to >5 years after surgery. Furthermore, these predictive algorithms identified with 90% accuracy for aTSA and 85% accuracy for rTSA which patients will achieve MCID IR score improvement and predicted with 85% accuracy for aTSA patients and 77% accuracy for rTSA which patients will achieve SCB IR score improvement at 2-3 years after surgery.

DISCUSSION

Our machine learning study demonstrates that active internal rotation can be accurately predicted after aTSA and rTSA at multiple postoperative time points using a minimal feature set of preoperative inputs. These predictive algorithms accurately identified which patients will, and will not, achieve clinical improvement in IR score that exceeds the MCID and SCB patient satisfaction thresholds.