The influence of deltoid tensioning on functional outcomes following reverse shoulder arthroplasty

BackgroundWe aimed to investigate the relationship between functional outcomes and radiological and clinical measurements (based on deltoid moment arm length measurements) of reverse total shoulder arthroplasty (RTSA) performed in patients for irreparable rotator cuff tears.MethodsThirty-eight patients who underwent RTSA after irreparable rotator cuff tears between 2016 and 2019 were included in the study. Patients with primary osteoarthritis, rheumatoid arthritis, or post-traumatic RTSA were excluded from the study. The patients were evaluated functionally using the range of motion, Quick DASH, and Constant Scores (CS). Deltoid lengthening was measured both clinically by the difference in upper extremity length (dUEL) and radiologically by the acromiohumeral distance (AHD) and deltoid lever length (DLL). AHD was measured with true anteroposterior radiographs and ultrasound guidance.ResultsThe mean age of the patients was 66.39 ± 7.92 (range, 49–83) years. Of 38 patients, 31 (81.57%) were female and 7 (18.43%) were male. The mean follow-up durations were 26.43 ± 17.05 (range, 12–58) months. The mean active anterior elevation (AAE), abduction (AAB), and external rotation (AER) increased from 57.32°, 41.25°, and 22.32° preoperatively to 149°, 110°, and 34° at the last follow-up, respectively. Preoperatively, the mean QuickDASH score was 58.04, and at the last follow-up, it was 38.19. The mean Constant Score rose from 24.75 preoperatively to 60.64 at the last follow-up. The AHD, DLL, and dUEL mean values were 2.346, 1.89, and 1.746 cm, respectively. There was a significant relation between the DLL and the AAE (P < .01).ConclusionOptimizing deltoid tension plays an essential role in regaining function, and this study demonstrates that lengthening the deltoid increases the patient’s ability to elevate anteriorly, likely by recreating the force-length relationship of the deltoid muscle.     

Long-term relation between deltoid muscle volume and clinical outcomes in a reverse shoulder arthroplasty

BackgroundDeltoid muscle function is important in reverse shoulder arthroplasty (RSA). Concerns are raised on the resistance of the deltoid muscle against the postoperative distalization. We hypothesize that a decreased volume of the deltoid muscle is related to worse clinical outcomes after a long-term follow-up. An observational study was conducted to evaluate the relation between volume of the deltoid muscle and clinical outcomes after a long-term follow-up on RSA.MethodsEligible for inclusion was patients who underwent RSA for cuff arthropathy after minimum 3 years follow-up. Fifty-nine patients were enrolled in this study. Preoperative volume was measured on magnetic resonance imaging or computed tomography. Postoperative deltoid volume was evaluated on ultrasonography. Distalization of the humerus was measured on radiographs. Clinical outcomes were measured by the Constant-Murley Score (CMS), Oxford Shoulder Score, and range of motion. Multivariable linear regression models were used to examine the association between the deltoid volume and clinical outcomes, and between distalization and deltoid volume or clinical outcomes.ResultsThe mean follow-up period was 88.7 ± 29.1 months. Postoperative deltoid volume positively correlated with both CMS (P = .045) and abduction strength, in both operated (P = .01) and contralateral side (P < .001). No association between deltoid volume and Oxford Shoulder Score or range of motion, and no association between preoperative volume and postoperative CMS was found. The mean distalization of the humerus was 21.2 mm [95% CI: 19.4-22.9 mm]. Distalization negatively correlated with deltoid volume (P = .012) and CMS (P = .009).ConclusionsPostoperative deltoid volume correlated with clinical outcomes as measured by CMS and abduction strength after a long-term follow-up on RSA.     

Glenosphere inclination and clinical outcomes after reverse shoulder arthroplasty

BackgroundThe relationship of numerous implant design and positioning-related variables with range of motion and clinical outcomes have been investigated for reverse shoulder arthroplasty (RSA). While glenosphere inclination has been investigated with regards to implant fixation and scapular notching, little research has been done on the association between glenosphere inclination and clinical outcomes. Therefore, the primary objective of this study was to investigate the relationship between preoperative glenoid inclination, postoperative glenosphere inclination and inclination change (∆INC) from pre- to postoperative on clinical outcomes after RSA.MethodsA multicenter retrospective study was conducted of RSAs with minimum 2-year clinical follow-up. All included patients had the same RSA prosthesis. Preoperative, postoperative, and ∆INC from pre-to postoperatively were measured for each patient. The primary study outcome was the minimum 2-year ASES score. Secondary outcomes were active range of motion, Constant-Murley score and Western Ontario Ostearthritis Shoulder (WOOS) score at a minimum of 2 years postoperatively. Receiver-operator characteristic curve analyses were performed to determine if any significant thresholds in inclination existed. Univariate analyses were performed with ANOVA to compare subgroup means. Finally, a multivariate logistic regression was performed to examine each inclination variable as a predictor of clinical outcome while controlling for patient and implant-related variables.ResultsEighty seven patients were included in the study. The mean age was 70 years and 53% of patients were male. The examiners had excellent reliability determined by intraclass correlation coefficients for all 3 measurements. There was no apparent correlation between preoperative inclination, postoperative inclination or ∆INC with minimum 2-year ASES scores. This was confirmed in the receiver-operator characteristic analyses, where no significant thresholds were found for each of the 3 assessed measurements (P> .05 for all analyses). A subgroup analysis comparing patients with low preoperative inclination (<10°) and patients with high preoperative inclination (>10°) stratified by the ∆INC demonstrated no significant association with inclination (P > .05 for all comparisons). In the multivariate regression analysis, inclination had no significant association with the minimum 2-year ASES scores.ConclusionFor the studied implant system, preoperative inclination, postoperative inclination and ∆INC did not have a significant association with postoperative clinical outcomes after RSA.Level of evidenceLevel III; Retrospective Comparison Study     

Review and clinical presentation in reverse shoulder arthroplasty in deltoid palsy

European Journal of Orthopaedic Surgery & Traumatology - Deltoid palsy is a classical contraindication for reverse shoulder arthroplasty (RSA). However, in cases associating axillary nerve...     

Anatomic total shoulder arthroplasty and reverse total shoulder arthroplasty for dislocation arthropathy yield comparable functional outcomes with the matched cohort

BackgroundThe aim of this study was to compare outcomes of anatomic total shoulder arthroplasty (aTSA) and reverse total shoulder arthroplasty (rTSA) after prior shoulder stabilization versus matched cohorts without previous stabilization surgery. Hypotheses were as follows: (1) patients undergoing aTSA or rTSA after stabilization procedures would have worse outcomes than matched cohorts and (2) patients undergoing TSA would have better outcomes after soft-tissue stabilization procedures (aTSA_ST or rTSA_ST) than after bony stabilization procedures (aTSA_B or rTSA_B).MethodsRetrospective cohort study was performed comparing (1) 36 patients who underwent aTSA and (2) 32 patients who underwent rTSA with prior shoulder stabilization with 3-to-1 matched cohorts (based on age, gender, and follow-up length) with no prior shoulder instability or surgery. Baseline demographics, perioperative data, adverse events (AEs), radiographic outcomes, functional outcome scores, range of motion (ROM), and patient satisfaction were analyzed. Subgroup analyses compared patients who underwent aTSA_ST or rTSA_ST with patients who underwent aTSA_B or rTSA_B.ResultsThe postoperative AE rate was 8.3% and 4.6% in the aTSA group and matched cohort, respectively (P = .404), with a trend toward a significantly higher incidence of aseptic glenoid loosening in the aTSA group (8.3% vs. 1.9%, P = .067). Functional outcomes, ROM, and patient satisfaction did not differ at follow-up >4 years. In the subgroup analysis, two AEs required reoperation among 25 patients who underwent aTSA_ST versus one among 11 patients who underwent aTSA_B, all related to aseptic loosening. There was a trend toward greater functional outcomes and satisfaction among patients who underwent aTSA_ST. There was a trend toward a clinically significant difference in active abduction at final follow-up favoring aTSA_ST (128 vs. 108 degrees, P = .096).The postoperative AE rate was 6.3% and 4.2% among the rTSA group and matched cohort, respectively (P = .632). Functional outcomes, ROM, and patient satisfaction did not differ at 4-year follow-up. In the subgroup analysis, no AEs were reported among 18 patients who underwent rTSA_ST and 14 patients who underwent rTSA_B. A trend toward greater functional outcomes and patient satisfaction favored patients who underwent rTSA_B, who achieved greater improvements in ROM from baseline and greater ROM in all planes at the final follow-up.ConclusionBoth aTSA and rTSA are reliable options for the treatment of dislocation arthropathy in appropriately selected patients. aTSA and rTSA after prior shoulder stabilization procedures have nearly equal rates of AEs and yield similar clinical and functional outcomes as matched cohorts. There may be an increased risk of glenoid aseptic loosening in aTSA after prior shoulder stabilization. Functional outcomes tend to be greater for patients who underwent aTSA_ST than those for patients who underwent aTSA_B. On the contrary, rTSA may optimize postoperative function when performed for dislocation arthropathy after bony rather than soft-tissue stabilization procedures.Level of evidenceLevel III; Retrospective Cohort Design; Treatment Study     

Onlay versus inlay reverse total shoulder arthroplasty: a retrospective comparison of radiographic and clinical outcomes

IntroductionRecent innovations in reverse shoulder arthroplasty (RSA) have presented 2 distinct humeral stem designs: an onlay system that rests above the anatomic neck and an inlay component that rests within the metaphysis. The purpose of this study is to compare clinical and radiographic outcomes between inlay and onlay-designed humeral stems in lateral center of rotation RSA implant systems.MethodsA retrospective cohort study was performed on primary RSA patients treated by 2 surgeons at 2 separate hospitals with a minimum 2-year follow-up. Patients were categorized based on treatment with an onlay or inlay humeral design and matched 1:1 by indication and age. Patient-reported outcome measures (PROMs), including the Simple Shoulder Test, American Shoulder and Elbow Surgeons, and Visual Analog Score for pain, as well as active motion (forward elevation, internal rotation) were recorded at pre- and postoperative intervals. An Inlay-Onlay index assessed the degree of inset or offset of each particular implant referencing the anatomic neck. Radiographic analysis focused on scapular notching, bone resorption around the humeral stem, and acromion stress fractures.ResultsA total of 92 patients participated in the 1:1 matched analysis (46 each group). Cohorts were similar in age, gender, indication, follow-up length, and preoperative PROMs, with the exception of Simple Shoulder Test. At the most recent follow-up, there were no differences in all PROMs between groups. There were no differences in active internal rotation, but patients with an onlay-configuration demonstrated greater external rotation (P< .001) and forward flexion (P< .001). Greater tuberosity and calcar resorption occurred in 34 (74%) and 18 (39%) patients with an onlay-designed prosthesis, compared to 13 (28%) and 1 (2%) in the inlay group, respectively (P< .0001). Both groups had low rates of scapular notching (P= 1.0), while acromial fractures occurred in 6 patients with an onlay stem and in 4 patients with the inlay stem (P= .73).ConclusionThere were no differences in clinical outcomes or incidence of acromial fractures following RSA with an onlay- or inlay-style humeral stem prosthesis. Bone resorption of the proximal humerus occurred more frequently in patients with an onlay prosthesis, suggesting that an inlay prosthesis may afford better prevention of humeral stress shielding.Level Of EvidenceLevel III; Retrospective Comparative Study     

Clinical and radiographic factors associated with internal rotation outcomes following reverse shoulder arthroplasty using an inlay stem design

BackgroundThe purpose of this study was to evaluate the relationship between preoperative subscapularis (SSc) status as well as radiographic factors with internal rotation (IR) following reverse shoulder arthroplasty (RSA). Our hypothesis was that increased glenosphere lateralization and SSc insertion lateralization and the absence of a preoperative SSc tear would be associated with improved postoperative IR (IR_F).MethodsA retrospective review was performed of primary RSAs (n = 132) by a single surgeon using a 135° inlay prosthesis. Range of motion including forward flexion (FF_F), external rotation (ER_F) and IR_F were evaluated at one year postoperative. IR_F was divided into high (≥L4) and low (≤L4) groups. Preoperative SSc status, glenosphere size, and postoperative positions of the glenosphere and humerus were assessed. Novel radiographic factors were used to assess lateralization including the lesser tuberosity scapula (LTS) and lateral glenosphere scapula (LGS) ratios.ResultsOnly 32% of patients achieved IR_F ≥ L4 postoperatively. Patients who achieved high IR_F had a lower incidence of preoperative SSc tear compared to those who had an IR_F < L4 (9% vs. 47%; P = .002). Higher LTS and LGS ratios were associated with improved IR_F (P < .001). The chance of having IR_F ≥ L4 increased by 86% (P = .049) and by 62% (P = .038) for every 0.1 increase in LGS ratio and LTS ratios, respectively.ConclusionWith a 135° inlay prosthesis design, an intact SSc preoperatively, as well as increased lateralization parameters, LTS and LGS ratios are associated with increased postoperative IR following RSA.Level of EvidenceLevel III; Retrospective Case-control Comparative Study