Changes in deltoid muscle tension after reverse shoulder arthroplasty as quantified by shear wave elastography: relationship with radiographic parameters and functional outcomes

IntroductionImplantation of a reverse shoulder arthroplasty (RSA) impacts deltoid length, shape and tension. Quantification of changes in deltoid muscle tension with implantation of RSA has remained elusive. The purpose of this study was to use shear wave elastography (SWE) to quantify deltoid muscle stiffness preoperatively, intraoperatively and postoperatively in patients undergoing RSA.MethodsTwenty patients scheduled to undergo RSA (ReUnion, Stryker) were prospectively enrolled in this study. A single observer trained in SWE quantified deltoid stiffness preoperatively, intraoperatively, and postoperatively. Clinical evaluation included pain, motion, quickDASH, ASES, Oxford, and subjective shoulder value scores. Preoperative and postoperative radiographs were measured by an independent observer to determine the lateralization and distalization shoulder angles (LSA and DSA). A statistical analysis was then performed to determine whether changes in deltoid muscle stiffness correlated with any of these parameters.ResultsImplantation of a RSA lead to an increase SWE deltoid stiffness value from 22.4 ± 4.2 kPa preoperatively to 29.9 ± 5.23 kPa (P˂ .0001) immediately after surgery, and 26.6 ± 6.6kPa (P= .03) at most recent follow-up. Preoperative SWE deltoid stiffness values did not differ when measured in the office or under anesthesia. Reverse arthroplasty did not significantly change the LSA (P= .051), but did increase the DSA (P< .0001). Greater SWE deltoid stiffness values correlated with better active elevation (P= .0128) better external rotation (P= .0247), and larger DSA (P= .0026). Elevation and external rotation showed a positive correlation with the DSA and a negative correlation with the LSA.ConclusionAfter implantation of one RSA design incorporating glenoid and humeral lateralization, deltoid stiffness as measured with SWE increased significantly. Deltoid stiffness seems to correlate with joint distalization, elevation and external rotation. SWE seems to be reliable to quantify deltoid stiffness after reverse shoulder arthroplasty.Level of EvidenceLevel IV; Diagnostic Study     

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.     

Revision to Reverse Total Shoulder Arthroplasty Restores Stability for Patients With Unstable Shoulder Prostheses

Background

Instability after shoulder arthroplasty remains a complication with limited salvage options. Reoperation for instability with anatomic designs has led to high rates of persistent instability, therefore we aimed to evaluate the use of RSA for treatment of prosthetic instability.

Questions/purposes

(1) After revision shoulder arthroplasty to a reverse prosthesis (RSA), what is the survivorship free from dislocations at 2 and 5 years? (2) What factors are associated with dislocations? (3) What is the survivorship free from revision after revision to RSA? (4) From preoperation to postrevision to RSA, what are the clinical outcomes—the proportion of patients with moderate to severe pain, shoulder elevation and external rotation ROM, American Shoulder and Elbow Surgeons scores, and Simple Shoulder Test scores?

Methods

All shoulder arthroplasties revised for prosthetic instability using RSA components between January 2004 and July 2014 were retrospectively studied. During the period in question, we performed 82 revisions for instability of an anatomic total shoulder arthroplasty (TSA) (n = 62), hemiarthroplasty (n = 13), or reverse TSA (n = 7). We typically used a reverse TSA to treat this problem, but we identified 12 treated in other ways, including revision of a TSA to hemiarthroplasty (n = 3), revision of a reverse TSA to hemiarthroplasty (n = 2), revision of hemiarthroplasty to a hemiarthroplasty (n = 1), and revision of an anatomic TSA to another anatomic TSA (n = 6). This left 70 patients for evaluation; of those, 65 (93%) were available for analysis at a mean of 3 years (range, 2–10 years). A total of seven patients died. Eight of the 65 shoulders were not evaluated during the last 5 years, including three in patients who died earlier. The mean age of the patients at the time of revision RSA was 65 years (range, 40–89 years). Data were obtained from a longitudinally maintained institutional joint registry. Instability was defined as severe subluxation confirmed on clinical and radiographic examinations. We evaluated pain and ROM, and Kaplan-Meier curves were used to estimate survivorship.

Results

The survivorship free from dislocation at 2 and 5 years was 87% (95% CI, 80%–94%) and 79% (95% CI, 67%–91%) respectively, with 10 of 65 (15%) patients having an episode of dislocation after revision surgery. Persistent instability was more common in those with a BMI greater than 35 kg/m² (hazard ratio [HR], 5; 95% CI, 2–16; p = 0.008) and prior hemiarthroplasty (HR, 5; 95% CI, 2–16; p = 0.005), whereas patients who had undergone a previous TSA were less likely to have persistent instability (HR, 0.08; 95% CI, 0.0–0.30; p < 0.001) The survival free from rerevision for any indication at 2 and 5 years was 85% (95% CI, 76%–94%) and 78% (95% CI, 66%–90%) respectively; with the numbers available, we were not able to find associated factors. Fewer patients had moderate or severe pain after revision to RSA (preoperative: 48 of 65 [74%]; postoperative: nine of 65 [14%]; p < 0.001). After surgery, patients showed improvement in shoulder elevation (preoperative: 42° [± 30°], postoperative: 112° [42°]; mean difference, 70° [95% CI, ? 83^o to 57°]; p < 0.001) and external rotation (preoperative: 20° [± 22°], postoperative: 42° [± 23°]; mean difference, 22° [95% CI, ? 30° to ? 14°]; p < 0.001). American Shoulder and Elbow Surgeons scores improved (preoperative: 21 [± 10], postoperative: 68 [± 14], mean difference, 46 [95% CI, ? 58 to ? 35]; p < 0.001); where a higher score is better. Simple Shoulder Test scores also improved (preoperative: 2/12 [± 2], postoperative: 7/12 [± 3]; mean difference, 5 [95% CI, ? 7 to ? 2.17]; p < 0.001); where a higher score is better.

Conclusions

Revision RSA for prosthetic instability after shoulder arthroplasty is associated with reasonable implant survival and few complications. Approximately one in seven patients will have a recurrent dislocation. In patients with persistent instability or with risk factors for instability, consideration should be given for use of larger glenospheres and increasing the lateral offset at the time of RSA.

Level of Evidence

Level IV, therapeutic study.

     

The inferior capsular-shift procedure for multidirectional instability of the shoulder.

Thirty-eight patients (forty-three shoulders) who had disabling multidirectional instability of the shoulder were managed with an inferior capsular-shift procedure through an anterior approach. All of the patients were followed for a minimum of two years. The postoperative range of motion of the shoulders was well maintained. The mean forward elevation was 172 degrees; external rotation, 77 degrees; and internal rotation, to the level of the eighth thoracic vertebra. Four patients (four shoulders) had recurrence of symptomatic and disabling multidirectional instability, but thirty-nine (91 per cent) of the shoulders continued to function well with no instability. Nine patients (24 per cent) continued to have episodes of apprehension, which correlated with the residual inferior and posterior translations found at the postoperative physical examination. Thirty-four patients (thirty-nine shoulders) stated that they were subjectively satisfied with the status of the shoulder, but four patients, in whom the instability had recurred, were not satisfied. Thirty-seven (86 per cent) of the shoulders were judged to have been improved by the procedure, the initial postoperative stability had been maintained, and the result had not deteriorated with time. Six shoulders, however, including the four with recurrent instability, were thought by the patient to have deteriorated with the increased duration of follow-up. It was our experience that if non-operative treatment of multidirectional instability of the shoulder failed, the inferior capsular-shift procedure provided satisfactory objective and subjective results. Failures and recurrences of symptomatic instability occurred early in the postoperative period. There appeared to be no deterioration of the results with follow-up to seventy-one months.     

Shoulder arthroplasty in patients with ipsilateral hemiparesis: a safe and durable procedure? A case series

HypothesisShoulder arthroplasty is a safe and durable procedure that provides pain relief, improved range of motion (ROM), and minimal complications for shoulder pain and dysfunction in patients with ipsilateral hemiparesis.MethodsThis is a retrospective review of all adult patients who underwent primary reverse total shoulder arthroplasty (RSA) or total shoulder arthroplasty (TSA) in the hemiparetic upper extremity at a single quaternary care academic medical center from 1988 to 2019. Patients were excluded if their neurologic insult was secondary to a spinal-cord injury, cerebral palsy, or inflammatory arthritis, if they underwent a hemiarthroplasty, if they exhibited mild hemiparesis (Medical Research Council Scale of ≥4), or if they had less than 30 days of radiographic follow-up. The primary clinical outcome was revision surgery for any reason. The secondary clinical outcomes included pain using the visual analog scale, ROM via active-assisted manual muscle testing (AAROM), and postoperative complications. The primary radiographic outcome was implant lucency using a standard scale.ResultsA total of 5 shoulders in 5 patients were included, 4 RSAs and 1 TSA with a mean clinical follow-up of 6.2 years (range: 1.42-14.2 years) and mean radiographic follow-up of 3.7 years (range: 31 days-13.5 years). No patient underwent revision surgery. The mean visual analog scale score significantly improved from 7.6 to 1.4 at the last follow-up (P = .005). The mean forward elevation AAROM improved from 27° preoperatively to 88° at the last follow-up (P = .015). There was no significant difference in external rotation at the last follow-up (P = .105). One patient had asymptomatic grade 1 glenoid component lucency with superior subluxation of the humerus after undergoing TSA at a final follow-up of 4.5 years. No other complications were reported.ConclusionShoulder arthroplasty is a durable procedure that provides pain relief, improved AAROM, and minimal complications in patients with ipsilateral hemiparesis. The increase in active-assisted forward elevation ROM can improve caregiver ease with hygiene and dressing. Patients in this study who underwent RSA did not have subsequent glenohumeral dislocation. Larger numbers of patients would be required for adequate power analysis regarding instability in this cohort of patients who may be at risk; our small series did not identify any instability events.Level of evidenceLevel IV; Treatment Study     

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 results of shoulder resurfacing hemiarthroplasty: Poor functional outcomes in rotator cuff deficient patients

Background: Shoulder resurfacing hemiarthroplasty is a bone-conserving procedure used in the treatment of multiple painful shoulder conditions. Previous studies have reported mixed results with some indicating that rotator cuff arthropathy leads to inferior clinical outcomes when compared to other preoperative diagnoses. We compared the medium- to long-term subjective and functional outcomes of resurfacing hemiarthroplasty performed for rotator cuff arthropathy versus other indications.Methods: Patients who underwent shoulder resurfacing hemiarthroplasty, with minimum two-year follow-up, were included for review. The primary outcome measure was the final postoperative American Shoulder and Elbow Surgeons score, while secondary measures included final postoperative active forward elevation, revision arthroplasty, as well as the change in pre- and postoperative outcome scores and forward elevation.Results: Eighty-four shoulders in 77 patients were reviewed, including 39 shoulders with preoperative rotator cuff arthropathy. Mean follow-up time was 76.82 months (range 24 to 147 months). Improvements in subjective outcome scores and visual analog pain scores were observed with all preoperative diagnoses following surgery. There was no significant difference in final postoperative subjective scores when comparing patients with rotator cuff arthropathy and those with an intact rotator cuff (66.0 ± 22.8 vs. 74.2 ± 20.3, p = 0.09). Final postoperative active forward elevation was significantly worse in the rotator cuff arthropathy group compared to other diagnoses (119.1˚± 41.8˚ vs 136.9˚ ± 34.6˚, p = 0.040). Patients with rotator cuff arthropathy lost an average of 26.9˚ of forward elevation while those with an intact rotator cuff gained an average of 8.7˚ postoperatively (p = 0.001). Six shoulders from the rotator cuff arthropathy group were revised to reverse total shoulder arthroplasty compared to two from all other groups (15.4% vs 4.4%, p = 0.183).Conclusion: Shoulder resurfacing hemiarthroplasty is effective in relieving pain and improving subjective outcome scores across all diagnoses but does not reliably restore or maintain function in rotator cuff deficient patients. In fact, patients with rotator cuff arthropathy lost a significant amount of range of motion after resurfacing hemiarthroplasty. While patients predictably improve in terms of pain scores and subjective outcome scores, caution should be exercised in performing this procedure in patients with rotator cuff arthropathy, even those with preserved preoperative overhead active range of motion, due to potential loss of active range of motion after surgery.Level of evidence: Level III; Retrospective Comparative Study     

Mini-open rotator cuff repair does not result in intractable stiffness

We conducted a study to determine whether intractable postoperative stiffness or deltoid damage results from primary arthroscopic anterior acromioplasty and mini-open repair of full-thickness tears of the superior rotator cuff. Eighty-three repairs (80 patients) were available for follow-up at a mean (range) of 57.2 (12-98) months. Range of motion at presentation and motion in contralateral shoulder at final follow-up were used for comparison. Significant improvements were seen in active forward elevation, passive forward elevation, and active external rotation at 90° abduction. Final motion in the operative and contralateral shoulders was similar. American Shoulder and Elbow Surgeons shoulder index improved significantly (P<.0001) from 50.0 before surgery to 88.3 after surgery. Although 1 patient had a symptomatic retear that required revision surgery, there were no cases of intractable stiffness, and there were no cases of deltoid damage.     

Triceps nerve to deltoid nerve transfer after an unsatisfactory intra-plexus neurotization of the posterior division of the upper trunk

IntroductionOur literature review did not reveal any study on the results of triceps to deltoid nerve transfer done as a secondary procedure after an unsatisfactory primary intraplexus neurotization of the posterior division of the upper trunk.Presentation of casesWe report on three adults with C5-C6 brachial plexus injury who had an unsatisfactory deltoid function following primary intraplexus neurotization. Patients presented to our clinic late (14–16 months after injury). All patients had poor shoulder abduction (<40°) despite the presence of visible and palpable deltoid contractions. A triceps to deltoid nerve transfer resulted in an excellent shoulder abduction (> 150°) in all patients.DiscussionThe primary surgery in our patients acted as a “baby-sitter” procedure; explaining the good results of the late secondary distal nerve transfer.ConclusionGood results may be obtained from a late distal nerve transfer for the deltoid muscle as long as there is partial innervation of the muscle.     

Does non-spherical humeral head with inlay glenoid re-center the glenohumeral joint?

BackgroundTreatment of glenohumeral osteoarthritis (OA) with Walch type B glenoid poses a challenge for orthopedic surgeons. Although various techniques have been described, it is still a major concern in terms of management and long-term results. We hypothesized that total shoulder arthroplasty (TSA) using a combination of non-spherical humeral head resurfacing (HHR) and inlay glenoid replacement would re-center the glenohumeral joint in patients with Walch type B glenoid without surgical correction of glenoid version.MethodsWe retrospectively screened patients who underwent TSA using a combination of non-spherical HHR and inlay glenoid replacement for primary glenohumeral OA with posteriorly subluxated humeral head (HH) (Walch Type B1, B2 and B3) between 2015 and 2019. Ratios of preoperative and postoperative HH subluxation were compared using Walch index and the point of contact ratio method. Two orthopedic surgeons performed radiographic measurements blinded to each other. Means of 2 independent measurements were included in the final analysis for each shoulder. We also screened for postoperative complications, dislocation events and radiographic loosening.ResultsInitial cohort included 49 patients. A total of 29 shoulders in 28 patients were eligible for screening. The numbers of shoulders with Walch type B1, B2, and B3 glenoids were 3, 22, and 4, respectively. Mean preoperative and postoperative Walch indices were 56.57 ± 6.08% and 49.47 ± 4.78%, respectively. The mean preoperative and postoperative point of contact ratios were 62.97 ± 8.45% and 50.08 ± 3.87%, respectively. The difference between preoperative and postoperative subluxation ratios was significant for both methods (P < .01). Inter-rater reliability was found to be good-excellent. The overall complication rate at a mean follow-up period of 37.79 months was 10.34% (3/29). One patient experienced deep vein thrombosis (DVT) (3.22%) on postoperative day 8. Two patients experienced infection (6.45%), one of which required a revision TSA (3.22%) at 19 months after surgery. No patient experienced shoulder dislocation and no loosening was detected on postoperative radiographs.ConclusionWhen coupled with an inlay glenoid component in patients with eccentric glenoid wear and posterior subluxation, glenohumeral re-centering was consistently observed in this challenging patient population without the use of joint correction or augmentation procedures. It will be important to follow the clinical outcomes over the long-term to determine whether these observations translate to better clinical results than other techniques currently employed to deal with eccentric erosion and posterior subluxation of the arthritic glenohumeral joint although recent published mid-term results suggest results equal to or better than previously reported results in literature with different reconstructive techniquesLevel of evidenceLevel IV; Retrospective cohort     

The anteromedial approach for shoulder arthroplasty: the importance of the anterior deltoid

Protection of the anterior aspect of the deltoid muscle is critical to the success of shoulder arthroplasty. Between 1975 and 1980, 75 patients with 81 shoulder arthroplasties had exposure via the anteromedial approach with careful anterior deltoid detachment through fascial tissues, systematic repair, and standardized rehabilitation with early passive range of motion. As with other reports on arthroplasty, pain was significantly reduced and motion was improved. No anterior deltoid detachments occurred; deltoid strength was preserved. Greater postoperative deltoid strength was statistically associated with lesser postoperative pain, greater postoperative active elevation, improved limb function, and an enhanced overall result rating. To understand the contemporary indications for this approach better, those undergoing shoulder arthroplasty between 1990 and 1994 were assessed. The anteromedial approach was used in 14 of these 236 shoulders (5.9%). This approach is currently reserved for patients with frail anterior deltoids that will not tolerate retraction, with severely osteopenic humeral shafts that will not tolerate torsion, with extreme scarring and an inflexible deltoid muscle, with severe bony deformity, or with posterosuperior rotator cuff tearing requiring repair. The importance of the anterior deltoid in shoulder arthroplasty cannot be denied. Use of the extended deltopectoral approach with preservation of the deltoid origin insertion is a very positive step forward. In uncommon instances where added exposure is needed, the anteromedial approach with careful attention to incision and repair of the deltoid with appropriate postoperative rehabilitation can accomplish the goal of maintaining anterior deltoid function and enhancing the success of shoulder arthroplasty.     

Effect of reverse total shoulder arthroplasty humeral inclination on glenohumeral range of motion,deltoid force,and glenoid strain: a biomechanical study

BackgroundReverse total shoulder arthroplasty (RSA) primarily varies between 2 implant design options: a 135 humeral stem inclination that closely resembles anatomic orientation, versus the Grammont-style 155 humeral stem inclination that further medializes and distalizes the center of rotation (COR). The purpose of this study was to compare deltoid force, glenoid strain, and simulated glenohumeral range of motion (ROM) between RSA 135 and RSA 155 designs, with a series of standardized permutations of glenosphere offset and rotator cuff pathology.MethodsTwelve fresh-frozen cadaveric shoulder specimens were studied using a shoulder simulator. Native shoulder motion profiles for reproducible abduction range of motion were established using a customized testing device. Optical 3-dimensional tracking and pressure sensors were used to accurately record glenohumeral range of motion (ROM), deltoid force, and glenoid strain for RSA 135 and RSA 155 designs. For each cohort, all combinations of glenosphere offsets and rotator cuff tendon involvement were evaluated.ResultsThere was no significant difference in the overall abduction ROM between the 155 and the 135 humeral stem implants (P = .75). Resting abduction angle and maximum abduction angle were significantly greater with a 155 + STD (standard offset) construct than with a 135 + STD construct (P < .001 and P = .01, respectively). Both stem inclinations decreased combined deltoid force requirements as compared the native shoulder with a massive cuff tear. Effective glenoid strain did not vary significantly between 135 + STD and 155 + STD constructs (P = .66).ConclusionOverall, range of motion between the 135 and the 155 humeral stem inclinations was not significantly different. The cumulative deltoid force was lower in RSA shoulders when compared to native shoulders with massive rotator cuff tears, highlighting the utility of both implant designs. The Grammont-style 155 stem coupled with a 2.5 mm inferior offset glenosphere required less deltoid force to reach maximum abduction than did the more anatomic, lateralized 135 stem coupled with a 4 mm lateral offset glenosphere.Level of EvidenceBasic Science, Biomechanics Controlled Laboratory Study     

Early radiographic outcomes following deltoid ligament repair in bimalleolar equivalent ankle fractures

BackgroundIndications for deltoid ligament repair in bimalleolar equivalent ankle fractures are unclear. This study compared radiographic outcomes in bimalleolar equivalent ankle fractures undergoing open reduction internal fixation (ORIF) +/? deltoid ligament repair.MethodsA retrospective review of 1024 ankle fractures was performed. Bimalleolar equivalent injuries treated with ORIF +/? deltoid ligament repair were included. Radiographic assessment was performed preoperatively, and at three months postoperatively.ResultsOne hundred and forty-seven ankle fractures met inclusion criteria with 46 undergoing deltoid ligament repairs. There was a significant decrease in medial clear space (1.93 ± 0.65 mm vs. 2.26 ± 0.64 mm, p = 0.01), and tibiofibular clear space (3.89 ± 1.20 mm vs. 4.87 ± 1.37 mm, p = 0.0001) at 3 months postoperative in the deltoid repair group compared to the no repair group. When syndesmotic fixation was performed, there were no differences between groups.ConclusionDeltoid ligament repair in bimalleolar equivalent ankle fractures resulted in reduced medial clear space, and tibiofibular clear space in the early postoperative period. These differences were small and remained within established normal limits.Level of clinical evidenceLevel III, retrospective cohort study.     

Polyethylene insert exchange for wear after total shoulder arthroplasty

Virtually no information is available in the literature to guide clinical decision-making in regard to modular polyethylene exchange with metal-backed glenoid components in total shoulder arthroplasty for the indication of polyethylene wear. This level IV study reports our experience with exchange of the modular polyethylene glenoid component during revision total shoulder arthroplasty. We retrospectively identified 12 shoulders in 11 patients who underwent exchange of the modular polyethylene glenoid component during revision arthroplasty. The primary reason for revision arthroplasty with polyethylene exchange was wear-through or displacement of the polyethylene portion of the glenoid component, but rotator cuff tearing and instability often coexisted. The average follow-up from time of revision to latest evaluation or repeat revision arthroplasty was 68 months. Preoperative pain was a mean of 4.5 (range, 4-5), and postoperative pain was a mean of 2.6 (range, 1-5). Preoperative average active forward elevation was 93 degrees, and external rotation was 51 degrees. Postoperative active forward elevation was 89 degrees, and external rotation was 64 degrees. Average patient satisfaction was rated as the same. According to the modified Neer rating system, 4 shoulders (33%) had a satisfactory result, and 8 (62%) had an unsatisfactory result. Polyethylene exchange of glenoid component after total shoulder arthroplasty can be an effective treatment option in patients who do not have coexistent rotator cuff tear or instability. For most, instability, rotator cuff tear, and glenoid wear occur together, and this is a challenging problem to treat successfully.     

Shoulder electromyography in multidirectional instability

We studied shoulder muscle activity in multidirectional instability (MDI) and multidirectional laxity (MDL) of the shoulder, our hypothesis being that altered muscle activity plays a role in their pathogenesis. Six muscles (supraspinatus, infraspinatus, subscapularis, anterior deltoid, middle deltoid, and posterior deltoid) were investigated by use of intramuscular dual fine-wire electrodes in 7 normal shoulders, 5 MDL shoulders, and 6 MDI shoulders. Each subject performed 5 types of exercise (rotation in neutral, 45 degrees of abduction, 90 degrees of abduction, flexion/extension, and abduction/adduction) on an isokinetic muscle dynamometer at two rates, 90 degrees /s and 180 degrees /s. After filtering, rectification, and smoothing, the electromyography signal was normalized by using the peak voltage of the movement cycle. In subjects with MDI, compared with normal subjects, activity patterns of the anterior deltoid were different during rotation in neutral and 90 degrees of abduction, whereas those of the middle and posterior deltoid were different during rotation in 90 degrees of abduction. In subjects with MDL, the posterior deltoid showed increased activity compared with normal subjects during adduction. Activity patterns of the supraspinatus, infraspinatus, and subscapularis appeared similar in both groups. Dual fine-wire electromyography offers insight into the complex role of shoulder girdle muscle function in normal movement and in instability. Altered patterns of shoulder girdle muscle activity and imbalances in muscle forces support the theory that impaired coordination of shoulder girdle muscle activity and inefficiency of the dynamic stabilizers of the glenohumeral joint are involved in the etiology of MDI. Interestingly, the abnormalities are in the deltoid rather than the muscles of the rotator cuff.     

Instability after shoulder arthroplasty: results of surgical treatment

BACKGROUND: Currently, there is little available information regarding the surgical treatment of instability following shoulder arthroplasty. The purpose of the present study was to review the results of revision surgery performed for the treatment of instability after shoulder arthroplasty to better define the causes of instability and the risk factors for an unsatisfactory outcome. METHODS: Between 1985 and 1999, thirty-three shoulders (seven of which had had a hemiarthroplasty and twenty-six of which had had a total shoulder arthroplasty) were treated surgically at our institution for anterior instability (nineteen shoulders) or posterior instability (fourteen shoulders). The primary arthroplasty had been performed for the treatment of degenerative arthritis in sixteen shoulders, arthritis of dislocation in six, acute fracture in four, rheumatoid arthritis in three, and other conditions in four. RESULTS: The instability was attributed to abnormal capsular tension and/or rotator cuff dysfunction in twenty-one shoulders, component malpositioning in one shoulder, and a combination of both in eleven shoulders. One shoulder was treated with removal of the components. In the remaining thirty-two shoulders, each of the elements that was contributing to the instability was specifically addressed at the time of surgery. Revision surgery restored stability in nine of the thirty-two shoulders. Anterior instability was associated with a higher failure rate than posterior instability was (p = 0.04). Although eleven shoulders had additional surgery for the treatment of recurrent instability, only fourteen of the thirty-three shoulders were stable at the time of the final follow-up. According to the Neer rating system, there were four excellent, six satisfactory, and twenty-three unsatisfactory results. CONCLUSIONS: Soft-tissue imbalance is present in most cases of instability following shoulder arthroplasty, and component malpositioning plays an additional role in some cases. More than one-half of the shoulders in the present study remained unstable despite attempts at revision. Surgical treatment of instability following arthroplasty is associated with only a modest success rate.     

Factors affecting internal rotation after reverse shoulder arthroplasty

BackgroundThe limitation or loss of internal rotation (IR) after the surgery is a major problem in reverse shoulder arthroplasty (RSA). The particular factors associated with postoperative IR remain unclear. We aimed to analyze the predictors of IR after RSA.MethodsWe included primary RSA patients with the following implants and a minimum of 1-year follow-up: Wright Aequalis (n = 25), DJO Encore (n = 29), Biomet Comprehensive (n = 40), and Exactech Equinoxe (n = 29). Age, sex, dominant hand, primary diagnosis, implant type, preoperative critical shoulder angle, pre- and postoperative acromiohumeral distance, lateral offset of implant, glenosphere inclination, peg-glenoid rim distance (PGRD), glenosphere overhang, scapular notching, subscapularis (SSc) repair, pre- and postoperative ROM, and functional scores were assessed. IR was assessed using a 10-point scale based on the following anatomical levels: from the greater trochanter to the buttocks (2 points), from the sacrum to L4 (4 points), from L3 to L1 (6 points), from T12 to T8 (8 points), and from T7 to T1 (10 points). Univariable and multivariable analyses were performed to identify the factors affecting the IR after RSA.ResultsOne hundred twenty-three shoulders (123 patients) with a mean follow-up of 30.59 ± 19.55 (range, 12–83) months were evaluated. In the univariable analysis, preoperative diagnosis [odds ratio (OR) = 0.243, P = 0.001], implant type (P = 0.002), PGRD (OR = 1.187, P = 0.003), and preoperative IR (P < 0.001) were found to be factors associated with postoperative IR. Preoperative IR was the only factor associated with postoperative IR in the multivariable analysis (P < 0.001). Patients with preoperative IR scores of 10 or 8 points showed significantly better IR after RSA than those with preoperative IR scores of 2 or 4 points (10 points vs. 2 or 4 points; OR = 15.433, P = 0.002, 8 points vs. 2 or 4 points; OR = 6.078, P < 0.001).ConclusionPreoperative IR was the only independent factor for IR after RSA. Patients with excellent preoperative IR had better postoperative IR than those with poor preoperative IR. Preoperative diagnosis, implant type, SSc repair, implant lateralization, glenosphere inferior placement, and scapular notching were not identified as independent predictors of IR after RSA in our sample size.     

Arm lengthening after reverse shoulder arthroplasty: a review

Purpose

The purpose of this review is to provide a better understanding of biomechanical changes induced by reverse shoulder arthroplasty (RSA), discuss the different techniques of radiographic assessment of upper limb lengthening after RSA and determine the ideal soft tissue tension that provides the best functional outcome without increasing the risk of complications.

Methods

Inclusion criteria were articles in which the primary interest was the technique of measuring upper-extremity lengthening after complications related to lengthening and its role in postoperative function; those written in English, French or German; and those that provided evidence levels I–IV relevant to search terms.

Results

Seven articles met our inclusion criteria. Postoperatively, changes in humeral length varied from minus five to five millimetres, and changes in upper-extremity length varied from 15 mm to 27 mm. The acromiohumeral distance averaged 23 mm. Humeral and arm shortening increased the risk of dislocation and led to poor anterior active elevation. The type of surgical approach did not play a role in postoperative function. Subclinical neurological lesions were frequent.

Conclusions

Studies in this systematic review indicate that deltoid tensioning by restoring humeral length and increasing the acromiohumeral distance is critical for adequate postoperative function and to prevent dislocation. Excessive arm lengthening should be avoided, with zero to two centimetres of lengthening being a reasonable goal to avoid postoperative neurological impairment.     

The effect of an early mobilization rehabilitation protocol on outcomes after reverse shoulder arthroplasty

BackgroundGiven the continued growth of reverse shoulder arthroplasty (RSA), it is important to optimize factors that contribute to successful outcomes. Rehabilitation after RSA is critical to achieve successful outcomes including patient function and satisfaction; however, the ideal rehabilitation program has not been established. The purpose of this study was to evaluate the effect of early mobilization (EM) compared with delayed mobilization (DM) on outcomes and function after RSA.MethodsA retrospective study of prospectively collected data was performed comparing 67 patients who underwent RSA in two groups: the EM group began a rehabilitation program immediately after surgery, and the DM group began after 4-6 weeks postoperatively. Preoperative and postoperative Constant shoulder score, American Shoulder and Elbow Surgeons (ASES) score, Penn Shoulder Score (PSS), shoulder satisfaction value as well as demographics, opioid usage, range of motion, 90-day complications, reoperation, and readmission rates were collected. Statistical analysis was performed between each group’s outcomes and for the change (delta) of outcomes from baseline to each postoperative time point.ResultsAt 6 weeks postoperatively, the EM group showed significantly higher scores in ASES function, PSS, active forward elevation, passive forward elevation, active external rotation, and passive external rotation. There was significantly lower narcotic usage in the EM group at 6 weeks. At 3 months postoperatively, the EM group showed a lower numerical rating score for pain and higher active forward elevation. At the last follow-up, there was a lower numerical rating score and greater degree for all ranges of motion for the EM group than that for the DM group. A greater change from baseline to 6 weeks postoperatively was seen for the EM group in shoulder satisfaction value, ASES function, PSS, active forward elevation, passive forward elevation, and internal rotation. From baseline to 3 months postoperatively, ASES pain, PSS, active forward elevation, and passive forward elevation improved significantly in the EM group. At the final follow-up, active forward elevation increased greater for the EM group. There were 3 complications (2 hematomas and 1 infection) in the DM group and none in the EM group.ConclusionThe EM rehabilitation protocol after RSA achieved lower opioid usage at 6 weeks, lower pain scores at each time point, and better range of motion during the final follow-up than DM protocol. There were no complications reported with the EM protocol, suggesting it is a safe alternative for postoperative recovery. Orthopedic surgeons should consider the EM rehabilitation protocol after RSA.     

Shoulder arthroplasty in patients with a prior anterior shoulder dislocation. Results of a multicenter study

BACKGROUND: Prior reports of shoulder arthroplasty performed for dislocation-induced arthropathy have included only patients who had had a prior stabilizing procedure. The purpose of this study was to report the results of shoulder arthroplasty in all patients with a prior anterior shoulder dislocation, including both those previously treated operatively and those previously treated nonoperatively. METHODS: Fifty-five shoulders undergoing arthroplasty for arthritis following a prior anterior shoulder dislocation were evaluated. Twenty-seven of the shoulders had undergone a prior anterior stabilization procedure. The measures used to evaluate the shoulders included the Constant score, adjusted Constant score, active mobility, subjective satisfaction, radiographic result, and complications. RESULTS: The shoulders were evaluated at a mean of 45.0 months. The Constant score improved from a mean of 30.8 points preoperatively to a mean of 65.8 points at the time of follow-up. The adjusted Constant score improved from a mean of 38.2% to a mean of 79.8%. Active forward flexion improved from a mean of 82.1 degrees to a mean of 138.9 degrees. Active external rotation improved from a mean of 4.0 degrees to a mean of 38.6 degrees. Fifty patients rated the result as good or excellent. Negative prognosticators included an older age at the time of the initial dislocation and a rotator cuff tear. No significant differences in demographic factors, pre-arthroplasty function, post-arthroplasty function, pre-arthroplasty radiographic findings, post-arthroplasty radiographic findings, complication rate, or reoperation rate were noted between the patients treated with a prior operation for the anterior instability and those treated nonoperatively. CONCLUSIONS: This investigation documented the good results obtainable with shoulder arthroplasty for the treatment of arthritis following anterior shoulder instability. In addition, our findings suggest that capsulorrhaphy-induced arthropathy may be indistinguishable from arthritis following nonoperatively treated anterior shoulder instability.