Dataset Information

Lateralized reverse shoulder arthroplasty maintains rotational function of the remaining rotator cuff.

ABSTRACT:

Background

Humeral rotation often remains compromised after nonlateralized reverse shoulder arthroplasty (RSA). Reduced rotational moment arms and muscle slackening have been identified as possible reasons for this impairment. Although several clinical studies suggest lateralized RSA may increase rotation, it is unclear whether this is attributable to preservation of rotational moment arms and muscle pretension of the remaining rotator cuff.

Questions/purposes

The lateralized RSA was analyzed to determine whether (1) the rotational moment arms and (2) the origin-to-insertion distances of the teres minor and subscapularis can be preserved, and (3) their flexion and abduction moment arms are decreased.

Methods

Lateralized RSA using an 8-mm resin block under the glenosphere was performed on seven cadaveric shoulder specimens. Preimplantation and postimplantation CT scans were obtained to create three-dimensional shoulder surface models. Using these models, function-specific moment arms and origin-to-insertion distances of three segments of the subscapularis and teres minor muscles were calculated.

Results

The rotational moment arms remained unchanged for the middle and caudal subscapularis and teres minor segments in all tested positions (subscapularis, -16.1 mm versus -15.8 mm; teres minor, 15.9 mm versus 15.3 mm). The origin-to-insertion distances increased or remained unchanged in any muscle segment apart from the distal subscapularis segment at 0° abduction (139 mm versus 145 mm). The subscapularis and teres minor had increased flexion moment arms in abduction angles smaller than 60° (subscapularis, 2.7 mm versus 8.3 mm; teres minor, -6.6 mm versus 0.8 mm). Abduction moment arms decreased for all segments (subscapularis, 4 mm versus -11 mm; teres minor, -3.6 mm versus -19 mm).

Conclusions

After lateralized RSA, the subscapularis and teres minor maintained their length and rotational moment arms, their flexion forces were increased, and abduction capability decreased.

Clinical relevance

Our findings could explain clinically improved rotation in lateralized RSA in comparison to nonlateralized RSA.

SUBMITTER: Greiner S

PROVIDER: S-EPMC3563780 | biostudies-literature | 2013 Mar

REPOSITORIES: biostudies-literature

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Publications

Lateralized reverse shoulder arthroplasty maintains rotational function of the remaining rotator cuff.

Greiner Stefan S Schmidt Christan C König Christian C Perka Carsten C Herrmann Sebastian S

Clinical orthopaedics and related research 20121201 3

<h4>Background</h4>Humeral rotation often remains compromised after nonlateralized reverse shoulder arthroplasty (RSA). Reduced rotational moment arms and muscle slackening have been identified as possible reasons for this impairment. Although several clinical studies suggest lateralized RSA may increase rotation, it is unclear whether this is attributable to preservation of rotational moment arms and muscle pretension of the remaining rotator cuff.<h4>Questions/purposes</h4>The lateralized RSA ...[more]

PMID: 23212769

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Project description:Background and hypothesisThe impact of preoperative fatty infiltration of specific rotator cuff muscles on the outcomes of reverse total shoulder arthroplasty (rTSA) has not been well defined. Preoperative fatty infiltration of the shoulder musculature will negatively affect rTSA outcomes.MethodsA comprehensive literature review was conducted as per the Preferred Reporting Items for Systematic Reviews and Meta-analyses using PubMed, Embase, OVID Medline, Scopus, Cinahl, Web of Science, and Cochrane databases for original, English-language studies evaluating effect of fatty infiltration of shoulder musculature on rTSA outcomes published from January 1, 2000 to present. Blinded reviewers conducted multiple screens. All included studies were graded based on the level of evidence, and data concerning patient demographics and postoperative outcomes were extracted.ResultsA total of 11 articles were included, including one level I article, three level III articles, and seven level IV articles. The review consisted of 720 patients and 731 shoulders (320 women and 157 men), with a mean age of 72.4 years. A single deltopectoral approach was performed for a majority of studies (627/731 shoulders), followed by a superolateral approach (70/731 shoulders) and a single transdeltoid approach (4/731 patients). Eleven studies reported data specifically about preoperative fatty infiltration of the rotator cuff musculature; the teres minor was studied most widely (298/731 shoulders), followed by the subscapularis (256/731 shoulders) and infraspinatus (232/731 shoulders). The Constant score (562/731 shoulders) and American Shoulder and Elbow Surgeons score (284/731 shoulders) were the most common recorded outcome scores. Fatty infiltration of the teres minor, supraspinatus, and infraspinatus was associated with worse range of motion after rTSA.ConclusionPreoperative fatty infiltration of the rotator cuff, particularly of the teres minor and infraspinatus, has a negative impact on subjective patient outcomes and restoration of range of motion, especially external rotation, after rTSA. The impact of fatty infiltration of the other rotator cuff muscles remains unclear, which may be due to intersurgeon differences in the handling of the remaining rotator cuff muscles or differences in implant design. The evaluated literature provides information on which patients can be educated about probable outcomes and restoration of function after rTSA.

Project description:BackgroundLateralized reverse shoulder arthroplasty (RSA) has emerged as an attempt to improve on some of the drawbacks of conventional RSA, such as glenoid notching and decrease in ROM. Although this new design is being used in clinical practice, the evidence is mostly limited to case series and has not been systematically reviewed.Questions/purposes(1) How much did patient-reported outcome measures (PROMs) and ROM improve among patients who receive a lateralized RSA implant? (2) What proportion of shoulders experience complications, revision surgery, or scapular notching?MethodsThe PubMed and EMBASE databases were searched from database inception to January 31, 2020. We included clinical studies that reported the PROMs and/or ROM of patients with insufficient rotator cuffs undergoing RSA with a lateralized implant. All other types of studies and those including patients with fractures, instability or escape, infection, rheumatologic disease, neurologic disease, or revision surgeries as an indication for RSA were excluded. PROMs and ROM were collected and are reported as mean values and ranges. Complications, revision surgery, and scapular notching are presented as proportions. The percentage of the mean change relative to the minimum clinically important difference (MCID) was calculated using the anchor-based value for each outcome. The Methodological Index for Non-randomized Studies (MINORS) was used to assess study quality. The initial search yielded 678 studies; 61 full-text articles were analyzed according to our eligibility criteria. After a detailed analysis, we included nine studies that evaluated 1670 patients (68% of whom [1130] were women) with a mean age of 71.8 ± 0.6 years. The mean follow-up period was 41.1 ± 5.6 months. The mean MINORS score was 12 ± 4.ResultsActive ROM improved for forward flexion (mean change 47° to 82°; MCID 12°), abduction (mean change 43° to 80°; MCID 7°), external rotation (mean change 8° to 39°; MCID 3°), and internal rotation (mean change -2 to 1 points). PROM scores also improved, including the American Shoulder and Elbow Surgeons score (mean change 20 to 50; MCID 20.9 points), Constant score (mean change 28 to 40; MCID 5.7 points), Simple Shoulder Test score (mean change 3 to 7; MCID 2.4 points), and VAS score (mean change -1.8 to -4.9; MCID -1.6 points). The proportion of shoulders with complications ranged from 0% (0 of 44) to 21% (30 of 140), and the proportion of shoulders with scapular notching ranged from 0% (0 of 76) to 29% (41 of 140). The proportion of patients undergoing revision ranged from 0% (0 of 44) to 13% (10 of 76) at short-term follow-up.ConclusionLateralized RSA is a reasonable alternative to medialized implants for patients with rotator cuff insufficiency because it might reduce the likelihood of scapular notching without apparently compromising PROMs or ROM. More studies are required to determine whether there is a direct correlation between the amount of lateralization and PROMs or ROM.

Project description:PurposeThe purposes of this study were to investigate the difference in value (benefit to cost ratio) of dermal allograft superior capsular reconstruction (SCR) versus reverse total shoulder arthroplasty (rTSA) for the treatment of massive rotator cuff tears (MRCTs) without arthritis; to compare the patient populations selected for the operations and report pre- and postoperative functional data; and to understand other characteristics of the 2 operations, including operating time, use of institutional resources, and complications.MethodsA retrospective, single-institution analysis during the study period 2014-2019 with MRCT treated with SCR or rTSA by 2 surgeons with complete institutional cost data and minimum 1-year clinical follow-up with American Shoulder and Elbow Surgeons (ASES) score. Value was defined as ΔASES/(total direct costs/$10,000).ResultsThirty patients underwent rTSA and 126 patients SCR during the study period with significant differences noted in patient demographics and tear characteristics between the groups (patients who underwent rTSA were older, less male, had more pseudoparalysis, had greater Hamada and Goutallier scores, and had more proximal humeral migration). Value was 25 and 29 (ΔASES/$10,000) for rTSA and SCR, respectively (P = .7). The total costs of rTSA and SCR were $16,337 and $12,763, respectively (P = .7). Both groups experienced substantial improvements in ASES scores: 42 for rTSA vs 37 for SCR (P = .6). The operative time for SCR was much longer (204 vs 108 minutes, P < .001) but complication rate lower (3% vs 13%, P = .02) versus rTSA.ConclusionsIn a single institutional analysis of the treatment of MRCT without arthritis, rTSA and SCR demonstrated similar value; however, the value calculation is highly dependent on institution specific variables and duration of follow-up. The operating surgeons demonstrated different indications in selecting patients for each operation. rTSA had an advantage over SCR in shorter operative time, whereas SCR demonstrated a lower complication rate. Both SCR and rTSA are demonstrated to be effective treatments for MRCT at short-term follow-up.Level of evidenceIII, retrospective comparative study.

Project description:Massive irreparable rotator cuff tears (RCTs) affect the clinical outcomes of reverse shoulder arthroplasty (RSA). However, the effects of subscapularis repair on the outcomes of RSA, based on the degree of posterior-superior RCTs, are unclear. This study aimed to examine the effect of subscapularis repair on three-dimensional joint contact forces (JCFs) based on the degree of posterior-superior RCT severity in RSA. Ten human in vivo experimental data were used as input to the musculoskeletal model. A six-degrees-of-freedom (DOF) anatomical shoulder model was developed and validated against three-dimensional JCFs. The 6-DOF musculoskeletal shoulder model of RSA was then developed by importing the reverse shoulder implant into the validated anatomical shoulder model. Based on the various types of posterior-superior RCT severity, inverse dynamic simulations of subscapularis-torn and subscapularis-repaired models of RSA were performed: from isolated supraspinatus tears to partial or massive tears of the infraspinatus and teres minor. The intact rotator cuff model of RSA was also simulated for comparison with the different types of models. Our results showed that the more posterior-superior RCTs progressed in RSA, the more superior JCFs were observed at 90°, 105°, and 120° abduction in the subscapularis-torn model. However, subscapularis repair decreased the superior JCF at those angles sufficiently. In addition, the teres minor muscle-tendon force increased as infraspinatus bundle tears progressed in both the subscapularis-torn and -repaired models, in order to compensate for the reduced force during abduction. However, the teres minor muscle-tendon force was not as high as that of the infraspinatus muscle-tendon, which could result in muscle force imbalance between repaired subscapularis and teres minor. Therefore, our results suggest that repairing the subscapularis and the repairable infraspinatus during RSA can improve glenohumeral joint stability in the superior-inferior direction by restoring muscle force balance between the anterior cuff (i.e., subscapularis) and posterior cuff (i.e., infraspinatus and teres minor). The findings of this study can help clinician decide whether to repair the rotator cuff during RSA to enhance joint stability.

Project description:Purpose To compare patient-reported and surgical outcome measures in patients with and without secondary shoulder stiffness (SSS) undergoing rotator cuff repair (RCR). Methods Patients undergoing rotator cuff repair from 2014 to 2020 with complete patient-reported outcome measures (PROMs) by the short-form 12 survey (SF-12) were retrospectively reviewed to identify if operative intervention for SSS was performed alongside the RCR. Those patients with operative intervention for SSS were propensity matched to a group without prior intervention for stiffness by age, sex, laterality, body mass index, diabetes mellitus status, and the presence of a thyroid disorder. The groups were compared by rotator cuff tear (RCT) size, surgical outcomes, further surgical intervention, rotator cuff retear rate, postoperative range of motion (ROM), and SF-12 results at 1 year after surgery. Delta values were calculated for component scores of the SF-12 and ROM values by subtracting the preoperative result from the postoperative result. Results A total of 89 patients with SSS were compared to 156 patients in the control group at final analysis. The patients in the SSS group experienced a significant improvement in the delta mental health component score (MCS-12) of the SF-12 survey that was not seen in the control group (P = .005 to P = .539). Both groups experienced significant improvement by the delta physical health component score (PCS-12) of the SF-12 survey (SSS: 7.68; P < .001; control: 6.95; P < .001). The SSS group also experienced greater improvement of their forward flexion (25.8° vs 12.9°; P = .005) and external rotation (7.13° vs 1.65°; P = .031) ROM than the control group. Conclusions Operative intervention of SSS at the time of RCR has equivalent postoperative SF-12 survey outcome scores when compared to patients undergoing RCR without preoperative stiffness despite those patients having lower preoperative scores. Level of Evidence Level III retrospective comparative study.

Dataset Information

Lateralized reverse shoulder arthroplasty maintains rotational function of the remaining rotator cuff.

Background

Questions/purposes

Methods

Results

Conclusions

Clinical relevance

Publications

Lateralized reverse shoulder arthroplasty maintains rotational function of the remaining rotator cuff.

Similar Datasets

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