Indications for reverse total shoulder arthroplasty in rotator cuff disease

The effect of glenoid component version and humeral polyethylene liner rotation on subluxation and impingement in reverse shoulder arthroplasty

BACKGROUND

A previously validated finite element modeling approach was used to determine how changes in glenoid component version and polyethylene liner rotation within the humeral component affect the arm abduction angle at which impingement between the inferior glenoid and the polyethylene liner occurs as well as the amount of subluxation generated by that impingement.

MATERIALS AND METHODS

Five glenoid component versions (5° anteversion; neutral; 5°, 10°, and 20° retroversion) and 7 polyethylene liner rotations (20° and 10° anterior; neutral; 10°, 20°, 30°, and 40° posterior) were considered, resulting in 35 different clinically representative models. The humerus was internally and externally rotated and extended and flexed, and the resulting impingement and subluxation were measured. To further analyze more global trends and to identify implantations least prone to subluxation, polyethylene liner rotation was additionally varied in coarser 30° increments across the entire 360° range.

RESULTS

All subluxation caused by impingement occurred during external rotation and extension, and external rotation produced nearly 10-fold more subluxation than extension. Neutral glenoid component version was associated with the least amount of subluxation for all polyethylene liner rotations. Posteriorly rotated polyethylene liners, which place the thick inferior region of the component away from the scapula, produced the least amount of subluxation. The 90° and 120° posterior liner rotations produced no subluxation, whereas the 30° and 60° anterior liner rotations produced the greatest amount of subluxation.

CONCLUSION

These results indicate that rotating modern radially asymmetric humeral polyethylene liners posteriorly can reduce the risk of subluxation leading to dislocation and increase external rotation range of motion.

Arthroplasty treatment of proximal humerus fractures: 14-year trends in the United States

OBJECTIVES

Proximal humerus fractures are a common injury in the elderly population that can usually be managed non-operatively. However, arthroplasty has become increasingly utilized for complex fractures and poor bone quality. We evaluated national trends in treatment, specifically looking at the adoption of reverse total shoulder arthroplasty.

METHODS

The incidence of proximal humerus fractures was calculated from the Nationwide Emergency Department Database (NEDD) from 2006 to 2012. The Nationwide Inpatient Sample (NIS) was used to select patients from 2000 to 2013 with proximal humerus fractures treated with open reduction and internal fixation (ORIF), total shoulder arthroplasty (TSA), reverse total shoulder arthroplasty (RSA), and hemiarthroplasty (HSA). RSA and TSA shared the same ICD-9 code until 2010.

RESULTS

The incidence of proximal humerus fracture was stable from 2006 to 2012. Hemiarthroplasty was the majority treatment choice for arthroplasty in the early 2000's. However, in 2008, there was a large decrease in utilization, to 51.3% in 2013. During this period, utilization of TSA greatly increased, coinciding with a large increase of RSA. By 2013, RSA made up 45.1% of arthroplasty procedures.

CONCLUSION

The rate of proximal humerus fracture appears stable, while we observed both an overall increase in operative intervention. RSA appears to be increasingly chosen over HSA for arthroplasty treatment of proximal humerus fractures, an observation more pronounced in older patients. While clinical results appear promising, it is important to remember that most proximal humerus fractures may be treated successfully with conservative management, and rapid adoption of new technology should be watched carefully to ensure appropriate use.

Effect of lateralized design on muscle and joint reaction forces for reverse shoulder arthroplasty

BACKGROUND

Manufacturers of reverse shoulder arthroplasty (RSA) implants have recently designed innovative implants to optimize performance in rotator cuff-deficient shoulders. These advancements are not without tradeoffs and can have negative biomechanical effects. The objective of this study was to develop an integrated finite element analysis-kinematic model to compare the muscle forces and joint reaction forces (JRFs) of 3 different RSA designs.

METHODS

A kinematic model of a normal shoulder joint was adapted from the Delft model and integrated with the well-validated OpenSim shoulder model. Static optimizations then allowed for calculation of the individual muscle forces, moment arms, and JRFs relative to net joint moments. Three-dimensional computer models of 3 RSA designs-humeral lateralized design (HLD), glenoid lateralized design, and Grammont design-were integrated, and parametric studies were performed.

RESULTS

Overall, there were decreases in deltoid and rotator cuff muscle forces for all 3 RSA designs. These decreases were greatest in the middle deltoid of the HLD model for abduction and flexion and in the rotator cuff muscles under both internal rotation and external rotation. The JRFs in abduction and flexion decreased similarly for all RSA designs compared with the normal shoulder model, with the greatest decrease seen in the HLD model.

CONCLUSIONS

These findings demonstrate that the design characteristics implicit in these modified RSA prostheses result in mechanical differences most prominently seen in the deltoid muscle and overall JRFs. Further research using this novel integrated model can help guide continued optimization of RSA design and clinical outcomes.

Cost-Effectiveness of Arthroscopic Rotator Cuff Repair Versus Reverse Total Shoulder Arthroplasty for the Treatment of Massive Rotator Cuff Tears in Patients With Pseudoparalysis and Nonarthritic Shoulders

PURPOSE

To determine the most cost-effective treatment strategy for patients with massive rotator cuff tears and pseudoparalysis of the shoulder without osteoarthritis of the glenohumeral joint (PP without OA). Specifically, we aimed to compare arthroscopic rotator cuff repair (ARCR) versus reverse total shoulder arthroplasty (RTSA) and investigate the effect of patient age on this decision.

METHODS

A Markov decision model was used to compare 3 treatment strategies for addressing PP without OA: (1) ARCR with option to arthroscopically revise once, (2) ARCR with immediate conversion to RTSA on potential failure, and (3) primary RTSA. Hypothetical patients were cycled through the model according to transition probabilities, meanwhile accruing financial costs, utility for time in health states, and disutilities for surgical procedures. Utilities were derived from the Short Form-6D scale and expressed as quality-adjusted life-years. Model parameters were derived from the literature and from expert opinion, and thorough sensitivity analyses were conducted. TreeAge Pro 2015 software was used to construct and assess the Markov model.

RESULTS

For the base-case scenario (60-year-old patient), ARCR with conversion to RTSA on potential failure was the most cost-effective strategy when we assumed equal utility for the ARCR and RTSA health states. Primary RTSA became cost-effective when the utility of RTSA exceeded that of ARCR by 0.04 quality-adjusted life-years per year. Age at decision did not substantially change this result.

CONCLUSIONS

Primary ARCR with conversion to RTSA on potential failure was found to be the most cost-effective strategy for PP without OA. This result was independent of age. Primary ARCR with revision ARCR on potential failure was a less cost-effective strategy.

LEVEL OF EVIDENCE

Level IV, economic and decision analysis.

A Critical Review on Prosthetic Features Available for Reversed Total Shoulder Arthroplasty

Reversed total shoulder arthroplasty is a popular treatment in rotator cuff arthropathy and in displaced proximal humeral fractures in elderly. In 2016, 29 models of commercially available designs express this popularity. This study describes all the different design parameters available on the market. Prosthetic differences are found for the baseplate, glenosphere, polyethylene, and humeral component and these differences need to be weighed out carefully for each patient knowing that a gain in one mechanical parameter can balance the loss of another. Patient specific implants may help in the future.

The rotator cuff muscles are antagonists after reverse total shoulder arthroplasty

INTRODUCTION

There is disagreement regarding whether, when possible, the rotator cuff should be repaired in conjunction with reverse total shoulder arthroplasty (RTSA). Therefore, we investigated the effects of rotator cuff repair in RTSA models with varying magnitudes of humeral and glenosphere lateralization.

METHODS

Six fresh frozen cadaveric shoulders were tested on a validated in vitro muscle-driven motion simulator. Each specimen was implanted with a custom adjustable, load-sensing RTSA after creation of a simulated rotator cuff tear. The effects of 4 RTSA configurations (0 and 10 mm of humeral lateralization and glenosphere lateralization) on deltoid force and joint load during abduction with and without rotator cuff repair were assessed.

RESULTS

Deltoid force was significantly affected by increasing humeral lateralization (-2.5% ± 1.7% body weight [BW], P = .016) and glenosphere lateralization (+7.7% ± 5.6% BW, P = .016). Rotator cuff repair interacted with humeral and glenosphere lateralization (P = .005), such that with no humeral lateralization, glenosphere lateralization increased deltoid force without cuff repair (8.1% ± 5.1% BW, P = .012). This effect was increased with cuff repair (12.8% ± 7.8% BW, P = .010), but the addition of humeral lateralization mitigated this effect. Rotator cuff repair increased joint load (+11.9% ± 5.1% BW, P = .002), as did glenosphere lateralization (+13.3% ± 3.7% BW, P < .001). These interacted, such that increasing glenosphere lateralization markedly increased the negative effects of cuff repair (9.4% ± 3.2% BW [P = .001] vs. 14.4% ± 7.4% BW [P = .005]).

CONCLUSION

Rotator cuff repair, especially in conjunction with glenosphere lateralization, produces an antagonistic effect that increases deltoid and joint loading. The long-term effects of this remain unknown; however, combining these factors may prove undesirable. Humeral lateralization improves joint compression through deltoid wrapping and increases the deltoid's mechanical advantage, and therefore, could be used in place of rotator cuff repair, thus avoiding its complications.

Activity levels after reverse shoulder arthroplasty

BACKGROUND

Aim of this study was to analyze whether patients undergoing reverse shoulder arthroplasty (RSA) surgery are able to successfully return to sports and afterwards.

METHODS

Thirty-eight patients treated with RSA for Cuff Tear Arthropathy (CTA) were included. Two sub-groups were built: Patients who have participated in sports activities within the last 5 years prior surgery [Group A: n = 21 (55 %)] and patients who have never participated in sports [Group B: n = 17 (45 %)]. Evaluation was based on a questionnaire asking types of sports, frequency, and time to return to sports.

RESULTS

Mean age in Group A at the time of surgery was 76.2 (65-85) years and 78.4 (68-92) years in Group B. Most patients were women [n = 35 (92 %)]. Mean follow-up was 4.8 years (2.4-9.4) years. Fifteen (71 %) patients in Group A participated in sports at the time prior to surgery. Fourteen (67 %) patients returned to sports after surgery. The returning rate was 93 %. Six (29 %) patients of Group A stated that one reason they underwent shoulder replacement surgery was to continue to participate in sports. All active patients performed swimming at final follow up.

CONCLUSIONS

Most patients being active prior to reverse shoulder arthroplasty surgery are successfully able to return to their activity afterwards.

Fatigue failure of reverse shoulder humeral tray components of a single design

BACKGROUND

Modularity in shoulder arthroplasty provides surgical flexibility and facilitates less-complex revision surgery. Modular designs must fit in the glenohumeral joint space, necessitating minimal thickness and careful material selection. The potential for fatigue fracture is higher, and fatigue fracture has been experienced by patients. The purpose of this study was to determine the impact of geometry and materials used for modular humeral trays from a single manufacturer.

METHODS

We consecutively retrieved 8 humeral trays of nearly identical designs: 4 Ti-6Al-4V (Ti) and 4 CoCrMo (CoCr). Optical microscopy and scanning electron microscopy were used, along with metallurgical techniques. Finite element and fatigue analyses of the stresses at the humeral tray taper informed observation interpretation.

RESULTS

Two Ti devices were revised for in vivo fracture. Scanning electron microscopy showed cracking in the other 2 Ti trays and no evidence of cracking in the CoCr components. A geometric difference in the CoCr devices resulted in a 25% decreased stress under simulated activities of daily living. Accounting for the tray material properties, the fatigue failure envelope ranged from 1000 to 1 million cycles for Ti and from 30,000 to >10 million cycles for CoCr.

CONCLUSIONS

All Ti humeral tray retrievals fractured in vivo or were cracked at the taper fillet. No CoCr retrievals showed signs of cracking. Finite element and fatigue analyses predict a 10-fold lifetime increase for the CoCr devices compared with the Ti devices. This study shows that fatigue failure is possible for some reverse shoulder components and is likely exacerbated by fillet radius, tray thickness, and material choice.

Irreparable Rotator Cuff Tears Without Arthritis Treated With Reverse Total Shoulder Arthroplasty

Background:

Irreparable rotator cuff (RC) tears without arthritis is a challenging clinical problem in young adults. Reverse total shoulder arthroplasty (RTSA) has been proposed as one of the surgical treatment options for this condition.

Methods:

In this review, we discuss the current understanding of the role of RTSA for the management of irreparable RC tears without arthritis based on authors personal experience and available scientific literature.

Results:

Reverse total shoulder arthroplasty (RTSA) is a constrained arthroplasty system that can allow the deltoid and remaining rotator cuff to substitute for the lost function of irreparable RC. Furthermore, the pain relief is consistent with often a dramatic improvement in patient comfort, shoulder function and stability. In patients with pseudoparalysis of the shoulder without advanced arthritis, RTSA effectively restores forward elevation above the shoulder but may not dramatically improve external (ER) or internal rotation (IR). However, due to concerns over implant longevity, caution has to be exercised when using RTSA for symptomatic irreparable RC tears with preserved active forward elevation (AFE) and in patients less than 65 years of age.

Conclusion:

RTSA is a reasonable surgical option for irreparable rotator cuff repair without arthritis. However, caution should be exercised when offering RTSA to young patients and patient without pseudoparalysis because they can have a higher complication and dissatisfaction rate. In addition, longevity of RTSA and subsequent need for revision surgery remains a significant concern in this population.

Reverse total shoulder arthroplasty in wheelchair-dependent patients

BACKGROUND

Wheelchair-dependent patients have a high incidence of shoulder pathology, often causing severe impairment. This study reports outcomes of wheelchair-dependent lower extremity-impaired patients with symptomatic shoulder arthritis or severe rotator cuff pathology treated with reverse total shoulder arthroplasty (RTSA).

METHODS

Data for 19 wheelchair-dependent patients who had an RTSA for symptomatic arthritis or rotator cuff pathology, or both, were obtained from the University of Florida Shoulder Arthroplasty Database. Included were 16 of 19 shoulders with adequate follow-up averaging 40 months. Functional outcome scores included the Simple Shoulder Test, University of California Los Angeles Shoulder Rating Scale, Shoulder Pain and Disability Index, American Shoulder and Elbow Surgeons score, Constant score, and 12-item Short Form (SF-12) health survey. Objective measures were active elevation, external rotation, and internal rotation. Radiographs were evaluated for lucent lines, notching, and prosthetic loosening.

RESULTS

All measured parameters, except the SF-12, significantly improved at the final follow-up. Functional outcome scores included Shoulder Pain and Disability Index, 45; Simple Shoulder Test, 7; American Shoulder and Elbow Surgeons, 73; University of California Los Angeles Shoulder Rating Scale, 30; Constant, 70; and SF-12, 33. Active elevation was 112°, and active external rotation was 29°. Most patients (83%) were satisfied. The complication rate was 25%; baseplate failure and dislocation occurred early, and periprosthetic humeral fracture secondary to infection occurred late. The notching rate was 42%.

CONCLUSIONS

Shoulder pain and dysfunction due to arthritis and rotator cuff pathology can result in the loss of independence in wheelchair-dependent patients. We investigated whether RTSA can sustain the increased loads placed by these patients during transfers. Wheelchair-dependent patients can benefit from an RTSA for shoulder pain and dysfunction but must accept worsened impairment during the immediate postoperative period and a higher complication rate than the general population treated with an RTSA.

Reverse total shoulder arthroplasty with combined deltoid reconstruction in patients with anterior and/or middle deltoid tears

BACKGROUND AND HYPOTHESIS

Deltoid disruption has traditionally been an absolute contraindication to performing a reverse total shoulder arthroplasty (RTSA), and options available to patients have been limited. We present a series of patients with deltoid tears that underwent concomitant RTSA with deltoid reconstruction. We hypothesize that this combined procedure provides an acceptable, functional alternative for this complex patient population.

MATERIALS AND METHODS

We retrospectively identified all patients who were treated by a single surgeon with a concomitant RTSA and deltoid reconstruction from 2004 to 2012 with minimum 24-month follow-up. Six shoulders in 5 patients met these criteria. The mean age was 69 years (range, 61-79 years), and the mean follow-up period was 76.8 months (range, 24-133 months). We compared preoperative and postoperative range of motion and Penn Shoulder Scores, including subscores, using paired t tests.

RESULTS

Mean forward elevation and external rotation increased from 48° and 12°, respectively, to 120° and 22°, respectively. Penn scores increased from 45.2 to 77.8 postoperatively (P = .03). The Penn satisfaction subscore, in particular, improved from 1.1 (of 10) to 9.0 (P = .005). There was a low rate of recurrent deltoid failure (1 of 6 shoulders), and there were no infections or revisions.

DISCUSSION

Deltoid reconstruction at the same time as RTSA is a viable treatment option as a salvage procedure for patients with deltoid deficiency who otherwise need RTSA for treatment of massive rotator cuff deficiency. In this small series, simultaneous RTSA and deltoid reconstruction resulted in a functional shoulder with a high level of satisfaction and good motion.

LEVEL OF EVIDENCE

Level IV; Case Series; Treatment Study.

Wear simulation strategies for reverse shoulder arthroplasty implants

Reverse total shoulder arthroplasty is a clinically accepted surgical procedure; however, its long-term wear performance is not known. The purpose of this work is to review wear simulator testing of reverse total shoulder arthroplasty, to develop a wear simulator protocol for reverse total shoulder arthroplasty, and to test it by performing a pilot study. The review of wear simulator testing in the literature revealed considerable variation in protocols. A combination of our own cadaveric testing and those of other research groups helped in determining the magnitude and direction of joint loading for the development of the present protocol. A MATCO orbital-bearing simulator was adapted using custom fixtures to simulate a circumduction motion of the shoulder under mildly adverse conditions, and a pilot study gave wear rates within the wide range found in the literature. Arguments were presented in support of the currently developed protocol, but it was also suggested that, rather than rely on one protocol, a series of simulator wear protocols should be developed to fully test the implant wear performance in reverse total shoulder arthroplasty.

Contact mechanics of reverse total shoulder arthroplasty during abduction: the effect of neck-shaft angle, humeral cup depth, and glenosphere diameter

BACKGROUND

Implant design parameters can be changed during reverse shoulder arthroplasty (RSA) to improve range of motion and stability; however, little is known regarding their impact on articular contact mechanics. The purpose of this finite element study was to investigate RSA contact mechanics during abduction for different neck-shaft angles, glenosphere sizes, and polyethylene cup depths.

METHODS

Finite element RSA models with varying neck-shaft angles (155°, 145°, 135°), sizes (38 mm, 42 mm), and cup depths (deep, normal, shallow) were loaded with 400 N at physiological abduction angles. The contact area and maximum contact stress were computed.

RESULTS

The contact patch and the location of maximum contact stress were typically located inferomedially in the polyethylene cup. On average for all abduction angles investigated, reducing the neck-shaft angle reduced the contact area by 29% for 155° to 145° and by 59% for 155° to 135° and increased maximum contact stress by 71% for 155° to 145° and by 286% for 155° to 135°. Increasing the glenosphere size increased the contact area by 12% but only decreased maximum contact stress by 2%. Decreasing the cup depth reduced the contact area by 40% and increased maximum contact stress by 81%, whereas increasing the depth produced the opposite effect (+52% and -36%, respectively).

DISCUSSION

The location of the contact patch and maximum contact stress in this study matches the area of damage seen frequently on clinical retrievals. This finding suggests that damage to the inferior cup due to notching may be potentiated by contact stresses. Increasing the glenosphere diameter improved the joint contact area and did not affect maximum contact stress. However, although reducing the neck-shaft angle and cup depth can improve range of motion, our study shows that this also has some negative effects on RSA contact mechanics, particularly when combined.

Outcomes of Combined Bone Marrow Stimulation and Patch Augmentation for Massive Rotator Cuff Tears

BACKGROUND

The high failure rate after surgical repair of massive rotator cuff tears is a consistent problem.

PURPOSE

To evaluate the clinical and radiological outcomes of arthroscopic rotator cuff repair with bone marrow stimulation and patch augmentation in patients with massive rotator cuff tears.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

This study included 21 patients who underwent bone marrow stimulation and patch augmentation (group 1) and 54 patients who underwent conventional repair (group 2) for massive rotator cuff tears. Postoperative clinical outcomes were evaluated based on visual analog scale (VAS) for pain, simple shoulder test (SST), University of California, Los Angeles (UCLA), Constant, and American Shoulder and Elbow Surgeons (ASES) scores at baseline, 1 year postoperatively, and final follow-up. Anatomic outcomes were evaluated by using postoperative magnetic resonance imaging at 1 year after surgery.

RESULTS

No significant differences in demographic characteristics and baseline data were observed between groups 1 and 2. Clinical symptoms were significantly improved at the final follow-up in both groups (P < .001). At the final follow-up, no significant differences were found in VAS pain (P = .676), SST (P = .598), UCLA (P = .100), Constant (P = .469), or ASES (P = .880) scores. However, the retear rate was lower in group 1 (4/21, 19.0%) than in group 2 (25/54, 46.3%) (P = .036), and the medial-row failure rate (type 2 retears) was much lower in group 1 (0/4, 0%) than in group 2 (18/25, 72.0%) (P = .014).

CONCLUSION

Concomitant bone marrow stimulation and patch augmentation significantly reduced retear and medial-row failure rates in the arthroscopic repair of massive rotator cuff tears.

Elucidating trends in revision reverse total shoulder arthroplasty procedures: a retrieval study evaluating clinical, radiographic, and functional outcomes data

BACKGROUND

The purpose of this study was to explore relationships between damage modes in explanted reverse total shoulder arthroplasty (RTSA) components, patient and radiographic risk factors, and functional data to elucidate trends in RTSA failure.

METHODS

Fifty RTSA systems, retrieved from 44 patients, with 50 polyethylene (PE) liners, 30 glenospheres, 21 glenoid baseplates, 13 modular humeral metaphases, and 17 humeral stems, were examined for damage modes, including abrasion, burnishing, dishing, embedding, scratching, and pitting. PE liners were also analyzed for delamination and edge deformation. Charts were reviewed for patient, surgical, and functional data. Pre-revision radiographs were analyzed for scapular notching and loosening.

RESULTS

Average term of implantation was 20 months (range, 0-81 months). Metallic components exhibited abrasion, burnishing, dishing, pitting, and scratching. PE liners displayed all damage modes. Damage was exhibited on 93% of glenospheres and 100% of PE liners. Of 29 aseptic shoulders, 13 showed evidence of scapular notching and 5 of humeral loosening. There was a moderate correlation between radiographically observed implant failure or dissociation and PE embedding (r = 0.496; P < .001). There were weak and moderate correlations between scapular notching severity and PE dishing (r = 0.496; P = .006), embedding (r = 0.468; P = .010), and delamination (r = 0.384; P = .040).

CONCLUSIONS

To date, this is the largest series of retrieved RTSA components and the first to relate damage modes to radiographic and clinical data. Most damage was observed on the PE liners, on both the articular surface and rim, and glenosphere components. Correlation of retrieval findings with radiographic and clinical data may help establish predictors of prostheses at risk for failure.

Mechanical tradeoffs associated with glenosphere lateralization in reverse shoulder arthroplasty

BACKGROUND

Scapular notching in reverse shoulder arthroplasty occurs in up to 97% of patients. Notching is associated with decreased strength and reduced motion and may lead to long-term failure due to polyethylene wear. Many implant systems lateralize the glenosphere to address scapular notching, but the mechanical tradeoffs of lateralization have not been rigorously evaluated. We hypothesized that lateralization would decrease bony impingement but also decrease the mechanical advantage of the deltoid.

METHODS

Finite element models were created using the same implants with different amounts of glenoid lateralization: 5 mm of medialization to replicate glenoid erosion, as well as 2.5, 5, 7.5, and 10 mm of lateralization. Tests were performed with static and dynamic scapulae for motion in either the coronal or scapular plane. The angle of impingement between the scapula and the humeral polyethylene was recorded, as was the deltoid force required to elevate the arm.

RESULTS

Increasing lateralization decreased impingement while increasing the deltoid force required to elevate the arm. Differences were found between the static and dynamic scapulae, with the dynamic scapula model having increased humeral adduction before impinging. The impingement angle was also substantially affected by the bony prominences on the inferior scapula, showing how individual bony anatomy can affect impingement.

CONCLUSION

Lateralization is effective in increasing impingement-free range of motion but also increases the deltoid force required to perform identical tasks. In addition, impingement is determined by scapular motion, which should be included in all shoulder models.

Does resident involvement have an impact on postoperative complications after total shoulder arthroplasty? An analysis of 1382 cases

BACKGROUND

The impact of resident involvement on total shoulder arthroplasty (TSA) complication rate is unknown. The purpose of this study was to assess whether resident involvement in TSA is associated with 30-day complication rates.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database was searched for all patients who underwent TSA between 2005 and 2012. Data were extracted for patient preoperative demographics, intraoperative variables, resident involvement in surgery, and 30-day postoperative complications. Resident and nonresident cases were grouped by a matched propensity score analysis. Univariate and multivariate analysis was performed to assess the effect of resident involvement on postoperative complications.

RESULTS

We analyzed 1382 patients who underwent primary TSA, with matched groups of 691 with and 691 without resident involvement. The overall rate of 30-day complications was 2.60% in TSAs in which a resident was involved compared with 3.91% when no resident was involved (P = .173). Operative time and hospital stay were shorter in cases in which a resident was present (P = .002 and P < .001, respectively). Independent risk factors significantly associated with TSA complications identified by multivariate regression were higher patient age, higher American Society of Anesthesiologists classification, congestive heart failure, insulin-dependent diabetes, and peripheral vascular disease.

CONCLUSION

Resident involvement in TSA procedures is not a risk factor for 30-day complications. Patient factors including increased age, diabetes, and cardiac disease are risk factors for TSA complications. This information can be used in preoperative counseling to reassure patients about safety of resident involvement in TSA and to optimize patient comorbidities before surgery.

Shoulder arthroplasty in New York State, 1991 to 2010: changing patterns of utilization

BACKGROUND

Shoulder arthroplasty is now used to treat an expanding variety of glenohumeral disorders.

METHODS

This study assessed the demographic patterns and utilization rates of shoulder hemiarthroplasty (HA) and anatomic or reverse total shoulder arthroplasty (TSA) within New York State (NYS) from 1991 to 2010. Using the New York Statewide Planning and Research Cooperative System database, all shoulder arthroplasty procedures that occurred within NYS during the study period were retrospectively identified and analyzed.

RESULTS

During the 20-year period, 24,040 shoulder arthroplasty procedures were performed. During the second decade (2001-2010), there was a 393% increase in utilization of TSA with a 98% increase in HA. This disproportionate increase is likely due to the introduction and expanding indications of reverse TSA as an effective procedure in place of HA for the treatment of proximal humerus fractures and rotator cuff arthropathy, as rotator cuff arthropathy as a primary indication for HA was significantly less prevalent in period 2. Also notable was an identifiable disparity in race; whites represented approximately 80% of the shoulder arthroplasty procedures in both decades, whereas African Americans made up <5%. This is significantly different from the general racial demographics of NYS during both periods analyzed.

DISCUSSION

It is clear that the volume of shoulder arthroplasty procedures performed in NYS is increasing, mirroring the national experience. This trend reflects the expanding indications, the general success of these procedures, the aging demographic of our population, and a greater desire and willingness of patients to consider operative management to maintain or to improve quality of life.

Early results after modular non-cemented reverse total shoulder arthroplasty: a prospective single-centre study of 38 consecutive cases

BACKGROUND

This study evaluated the outcome of a third generation modular non-cemented reverse total shoulder arthroplasty (RTSA) in incongruent glenohumeral degeneration with severe rotator cuff deficiency.

MATERIALS AND METHODS

Thirty-eight consecutive RTSA with a mean age of 72 years (range 58-89 years) were prospectively enrolled. Mean follow-up was 24 months (range 21-29 months). Pain and standardized clinical functional scores were monitored. Radiographic and MRI findings have been scored and correlated to clinical outcome and complication rate.

RESULTS

Preoperative pain decreased significantly from VAS 8 to 2 at 24 months postop., as ROM improved significantly, by at least doubling preoperative values of elevation, abduction, and external rotation. Nevertheless, internal rotation languished. The preoperative median constant was 18 points and 70 points 24 months postop. (p < 0.001). Initial median DASH was 95 vs. 50 2 years after surgery (p < 0.001). Median prospective ASES was 23 (IQR 8-33) vs. 70 points (p < 0.001) at final follow-up. Each outcome measurement improved significantly at 6, 12, and 24 months follow-up. There was no significant correlation between pre-operative radiographic findings of osseous and/or soft-tissue degeneration and short-term clinical outcome and/or complication rate (13 %). At final follow-up, 54 % showed radiographic signs of inferior scapular notching. There was no revision and/or loosening observed.

CONCLUSION

RSTA with this modular system results in significant pain relief and improvement of functional clinical outcomes. However, longevity of the device is currently unknown.

Reverse Shoulder Arthroplasty for Management of Postinfectious Arthropathy With Rotator Cuff Deficiency

Treatment of patients with rotator cuff deficiency and arthritis in the setting of a prior glenohumeral infection (postinfectious arthropathy) is complex, with little evidence to guide treatment. The current authors present their approach to management of these patients and clinical outcomes after reverse shoulder arthroplasty (RSA). All primary RSAs performed for postinfectious arthropathy and rotator cuff deficiency with native glenohumeral joints were identified in a prospective shoulder arthroplasty registry. Eight patients with a minimum of 2-year follow-up were included in the analysis. Clinical outcomes, including the Constant score, the American Shoulder and Elbow Surgeons (ASES) score, the Western Ontario Osteoarthritis Shoulder (WOOS) index, the Single Assessment Numeric Evaluation (SANE) score, and range of motion measurements, were assessed preoperatively and at final follow-up. At an average follow-up of 4.4 years, no patient had a clinically detectable recurrence of infection. Significant improvements were noted in all outcome scores from preoperative evaluation to final follow-up after RSA, including Constant score (P=.003), ASES score (P<.001), WOOS index (P=.002), SANE score (P=.025), forward flexion (P<.001), abduction (P<.001), and external rotation (P=.020). Seven of 8 patients reported they were satisfied or very satisfied at final follow-up. Reverse shoulder arthroplasty can be performed in patients without significant medical comorbidities in the setting of postinfectious arthropathy and rotator cuff deficiency with a low risk of recurrence of infection. Significant clinical improvements were noted at short-term follow-up.

Glenosphere dissociation after reverse shoulder arthroplasty

BACKGROUND

Reverse shoulder arthroplasty (RSA) is gaining popularity for the treatment of debilitating shoulder disorders. Despite marked improvements in patient satisfaction and function, the RSA complication rate is high. Glenosphere dissociation has been reported and may result from multiple mechanisms. However, few RSA retrieval studies exist.

METHODS

We reviewed our RSA database and identified patients with glenosphere dissociation between 1999 and 2013. Prosthesis type, glenosphere size, and contributing factors to dissociation were noted. Five retrieved implants were available for analysis, and evidence of wear or corrosion on the Morse taper was documented. Further, we biomechanically investigated improper Morse taper engagement that may occur intraoperatively as a potential cause of acute dissociation.

RESULTS

Thirteen patients with glenosphere dissociation were identified (0.5 months to 7 years postoperatively). Glenosphere size distribution was as follows: 32 mm (n = 1), 36 mm (n = 4), 40 mm (n = 6), and 44 mm (n = 2). Incidence of dissociation was correlated to glenosphere size (P < .001). Taper damage was limited to fretting wear, and there was minimal evidence of taper corrosion. Biomechanically, improper taper engagement reduced the torsional capacity of the glenosphere-baseplate interface by 60% from 19.2 ± 1.0 N-m to 7.5 ± 1.5 N-m.

CONCLUSION

We identified several mechanisms contributing to glenosphere dissociation after RSA, including trauma and improper taper engagement. Limited evidence of corrosive wear on the taper interface was identified. Although it is rare, the incidence of glenosphere dissociation was higher when 40- and 44-mm glenospheres were implanted compared with smaller glenospheres (32 and 36 mm), probably because of the larger exposed surface area for potential impingement.

The effect of glenosphere diameter in reverse shoulder arthroplasty on muscle force, joint load, and range of motion

BACKGROUND

Little is known about the effects of glenosphere diameter on shoulder joint loads. The purpose of this biomechanical study was to investigate the effects of glenosphere diameter on joint load, load angle, and total deltoid force required for active abduction and range of motion in internal/external rotation and abduction.

METHODS

A custom, instrumented reverse shoulder arthroplasty implant system capable of measuring joint load and varying glenosphere diameter (38 and 42 mm) and glenoid offset (neutral and lateral) was implanted in 6 cadaveric shoulders to provide at least 80% power for all variables. A shoulder motion simulator was used to produce active glenohumeral and scapulothoracic motion. All implant configurations were tested with active and passive motion with joint kinematics, loads, and moments recorded.

RESULTS

At neutral and lateralized glenosphere positions, increasing diameter significantly increased joint load (+12 ± 21 N and +6 ± 9 N; P < .01) and deltoid load required for active abduction (+9 ± 22 N and +11 ± 15 N; P < .02), whereas joint load angle was unaffected (P > .8). Passive internal rotation was reduced with increased diameter at both neutral and lateralized glenosphere positions (-6° ± 6° and -12° ± 6°; P < .002); however, external rotation was not affected (P > .05). At neutral glenosphere position, increasing diameter increased the maximum angles of both adduction (+1° ± 1°; P = .03) and abduction (+8° ± 9°; P < .05). Lateralization also increased abduction range of motion compared with neutral (P < .01).

CONCLUSIONS

Although increasing glenosphere diameter significantly increased joint load and deltoid force, the clinical impact of these changes is presently unclear. Internal rotation, however, was reduced, which contradicts previous bone modeling studies, which we postulate is due to increased posterior capsular tension as it is forced to wrap around a larger 42 mm implant assembly.

[Total reverse shoulder replacement. Evaluation of the clinical results and complications in a series of 52 cases]

OBJECTIVE

To evaluate the clinical results and analyse the complications of total reverse shoulder replacement performed in our centre over an 8 year period.

MATERIAL AND METHOD

A retrospective study was conducted on 50 patients (52 shoulders), with a mean age of 70.15 years (range 51 to 84 years) between December 2004 and December 2012, who received a total reverse shoulder replacement, all performed by the same surgeon. The results have been evaluated according to clinical data, radiography study, a satisfaction scale, and the Constant scale, with a minimum follow-up of 16 months. Five of the cases (9.62%) had been intervened due to fractures of the proximal end of the humerus, 6 cases (11.53%) as surgical consequence of a prosthesis revision, 10 cases (19.23%) due to fracture sequelae, and 30 cases (59.62%) were patients with arthropathy due to a massive fracture of the rotator cuff.

RESULTS

After a mean follow up of 35.78 months (range, 16-82), satisfactory clinical results were obtained in 80% of cases, with a mean preoperative Constant of 27.7 points, and reaching 67.1 points 12 months after the operation. On the visual analogue scale, 8.25 points were obtained before the surgery, which decreased to 2.25 points 12 months later. The complications rate was 15.38%, which were due to an intra-operative fracture (1.92%), deep infection (3.84%), instability (3.84%), and early mechanical loosening (3.84%). Scapular notching was observed in the radiographic study in 9 (17.3%) cases.

DISCUSSION AND CONCLUSIONS

After the results obtained, it could be said that total reverse shoulder replacement achieved encouraging results in the short term for the treatment of glenohumeral arthrosis and massive tears of the rotary cuff. On analysing our series, it can be seen that the complications rate is much higher when it is used to treat fracture sequelae in which there is a loss of proximal humerus bone stock.

A quantitative analysis of the effect of baseplate and glenosphere position on deltoid lengthening in reverse total shoulder arthroplasty

CONTEXT

Optimizing deltoid tension is important to achieve maximal function after reverse total shoulder arthroplasty (RTSA), but the effects of baseplate and glenosphere positions on deltoid tension have not been quantified.

AIMS

To quantify deltoid elongation and elongation to failure under physiologic loads with three baseplate-glenosphere configurations with increasing inferior offset.

SETTINGS AND DESIGN

Cadaver biomechanical study.

MATERIALS AND METHODS

Twenty-four cadaver shoulders were divided into three groups. The starting point for baseplate insertion in Group 1 was the center of the glenoid, with glenospheres placed in minimal inferior offset (0.5 mm). Groups 2 and 3 baseplates were placed 2 mm inferior to the center point and glenospheres in minimal (2.5 mm) offset (Group 2) or maximal (4.5 mm) offset (Group 3). Tensile testing was done to quantify deltoid elongation and evaluate failure.

STATISTICAL ANALYSIS USED

A one-way analysis of variance was performed to detect statistically significant differences among treatment groups. A post-hoc Neuman-Keul's comparison was conducted to perform discrete comparisons among treatment groups.

RESULTS

Deltoid elongation after loading decreased with increasing inferior offset of >2.5 mm. No significant difference in deltoid yield load was found among groups. The percent of elongation was decreased significantly between groups 2 and 3. Deltoid displacement at failure decreased from 33.3 mm for Group 2-17.3 mm for Group 3. 16 of the 24 specimens (67%) failed by anterior deltoid detachment from the acromion.

CONCLUSIONS

Increasing inferior offset in RTSA constructs appears to increase stretch forces on the deltoid, resulting in a diminished ability of the deltoid to further elongate under physiologic loads, (most pronounced when the inferior offset exceeds 2.5 mm) and significantly decreasing the yield displacement of the construct.

Assessment and treatment strategies for rotator cuff tears

Tears of the rotator cuff are common and becoming an increasingly frequent problem. There is a vast amount of literature on the merits and limitations of the various methods of clinical and radiological assessment of rotator cuff tears. This is also the case with regard to treatment strategies. Certain popular beliefs and principles practiced widely and the basis upon which they are derived may be prone to inaccuracy. We provide an overview of the historical management of rotator cuff tears, as well as an explanation for how and why rotator cuff tears should be managed, and propose a structured methodology for their assessment and treatment.

Outcomes of staged bilateral reverse shoulder arthroplasties for rotator cuff tear arthropathy

BACKGROUND

The purpose of this study was to evaluate outcomes in patients with rotator cuff tear arthropathy after staged bilateral reverse shoulder arthroplasties (RSAs) and to compare them with an age-, gender-, and diagnosis-matched control group with a unilateral RSA.

METHODS

We identified 11 patients with bilateral RSAs for rotator cuff tear arthropathy with a minimum of 2-year follow-up in a prospective shoulder arthroplasty registry. The bilateral group was matched to a control group of 19 patients with a unilateral RSA. Shoulder function scores, mobility, patient satisfaction, and activities of daily living were assessed preoperatively and at final follow-up.

RESULTS

There was no statistical difference between the first RSA or second RSA and the control group regarding age, gender, or follow-up. No group differences were noted preoperatively for shoulder function scores or mobility (P > .10). All groups significantly improved on all shoulder function scores (Constant score, American Shoulder and Elbow Surgeons score, Western Ontario Osteoarthritis of the Shoulder index, Single Assessment Numeric Evaluation score) and mobility at final follow-up (all P < .01). There were no significant differences in shoulder function scores or mobility between the first and second RSA in the bilateral group or between either shoulder in the bilateral group and the unilateral group (all P > .10). Patient satisfaction improved and patients were successfully able to perform many important activities of daily living after bilateral RSAs.

CONCLUSIONS

Patients with bilateral rotator cuff tear arthropathy can be advised that staged bilateral RSAs can be successful when indicated. Improvements in shoulder function scores, patient satisfaction, and mobility are possible for both the first RSA and the second RSA.

Workers' compensation claims and outcomes after reverse shoulder arthroplasty

BACKGROUND

The effect of workers' compensation claims on outcomes after reverse shoulder arthroplasty (RSA) has not been investigated. The purpose of this study was to evaluate outcomes after RSA in patients with a workers' compensation claim and to compare them with a control group without a workers' compensation claim.

METHODS

We identified 14 primary RSAs completed in patients with a workers' compensation claim and a minimum of 2 years of follow-up in a prospective shoulder arthroplasty registry. Fourteen patients without a workers' compensation claim served as the age-, gender-, and diagnosis-matched control group. The Constant score, the American Shoulder and Elbow Surgeons score, the Western Ontario Osteoarthritis of the Shoulder Index, the Single Assessment Numeric Evaluation score, mobility, and the patient's satisfaction were assessed for both groups preoperatively and at final follow-up.

RESULTS

There were no differences between the groups regarding patient demographics, duration of follow-up, complications, preoperative shoulder function scores, or preoperative mobility (P > .05). Both groups significantly improved on all shoulder function scores and for mobility from preoperative to final follow-up (all P < .001); however, the workers' compensation group had significantly worse Constant (P = .002), American Shoulder and Elbow Surgeons (P = .003), and Western Ontario Osteoarthritis of the Shoulder Index (P = .001) scores. Only 57% of the workers' compensation group reported that they were satisfied or very satisfied at final follow-up compared with 93% in the control group. The workers' compensation group had a lower return to work rate (14.2% vs 41.7%), but this did not reach statistical significance (P = .117).

CONCLUSION

Patients with a workers' compensation claim had significant improvements after RSA, but they achieved significantly worse outcomes compared with the control group.

Risk factors for periprosthetic infection after reverse shoulder arthroplasty

BACKGROUND

Management of periprosthetic infection after reverse shoulder arthroplasty (RSA) remains a challenge. Whereas the infection rate after RSA has improved, more information would be helpful to identify patient risk factors for infection after RSA. The purpose of this study was to evaluate risk factors for infection after RSA.

METHODS

We identified 301 primary RSAs with a minimum of 1-year follow-up in a prospectively collected shoulder arthroplasty registry. We performed bivariate and multivariable logistic regression analyses to assess the association between patient demographic and clinical characteristics (age, sex, smoking, diabetes, rheumatoid arthritis, body mass index, and history of prior failed hemiarthroplasty or total shoulder arthroplasty) and periprosthetic infection after RSA.

RESULTS

There were 15 periprosthetic infections after RSA (5.0%). Patients with a history of RSA for failed arthroplasty (odds ratio, 5.75; 95% confidence interval, 2.01-16.43; P = .001) and patients younger than 65 years had an increased risk for development of an infection (odds ratio, 4.0; 95% confidence interval, 1.21-15.35; P = .021). History of smoking, diabetes, rheumatoid arthritis, or obesity did not contribute to an increased risk of infection after RSA.

CONCLUSIONS

This is the first study evaluating risk factors for infection after RSA while controlling for confounding variables with multivariable analysis. The greatest risk factors for infection after RSA were history of a prior failed arthroplasty and age younger than 65 years. Patients with these clinical characteristics should be counseled preoperatively about the increased risk for development of infection after RSA.

Quantifying rotator cuff atrophy and fatty degeneration at the supraspinatus origin in the scapular fossa

PURPOSE

The aim of this study was to evaluate the location difference (distance) between the conventional Y-view (CYV) and the bony origin of the supraspinatus, and therefore, to suggest hypotrophy measurement in the CYV could be highly influenced by retraction of a torn tendon.

METHODS

Ninety five arthroscopically repaired rotator cuff tears were retrospectively enrolled in this study. The most lateral portion of the osseous origin of the supraspinatus muscle [the Y-view at the level was newly defined as the supraspinatus origin-view (SOV)] and the CYV were determined on the MRI, and location discrepancy between the two levels was measured. Fatty degeneration and cross-sectional areas of rotator cuff muscles were measured on both views. Subgroup analyses were performed in partial-thickness tears and full-thickness tears with tendon retraction.

RESULTS

Distance between the SOV and CYV was 11.2 ± 3.7 mm. Discrepancy of the supraspinatus areas at the two views was greater in full-thickness tears than it was in partial-thickness tears without retraction. In the full-thickness tear group, correlation analysis between retraction and cross-sectional areas of the supraspinatus in both views exhibited statistical significance [Pearson's correlation coefficients = 0.500 (P < 0.001) in the CYV and 0.283 (P = 0.017) in the SOV]; however, the correlation was stronger in the CYV. Ratings of fatty degeneration were similar in both views.

CONCLUSIONS

There is considerable location discrepancy between the osseous origin of the supraspinatus at the suprascapular fossa and the CYV in which fatty degeneration and hypotrophy are routinely measured.

LEVEL OF EVIDENCE

Case series, Level IV.

Reverse Total Shoulder Arthroplasty for Recurrent Shoulder Dislocation in an Elderly Patient: A Case Report

CASE

We present a case of a seventy-one-year-old woman with recurrent anterior dislocation of the shoulder in the setting of an irreparable rotator cuff tear and degenerative joint disease.

CONCLUSION

In an elderly patient with recurrent anterior shoulder dislocation and an irreparable rotator cuff tear, reverse total shoulder arthroplasty (RTSA) is a viable surgical intervention. In the case presented here, RTSA resulted in the patient exhibiting increased range of motion, reporting an improved quality of life, and having no additional dislocation events as of the two-year follow-up.

Preoperative opioid use and outcomes after reverse shoulder arthroplasty

BACKGROUND

The potential adverse effect of preoperative opioid use on outcomes after reverse shoulder arthroplasty (RSA) has not been investigated. The purpose of this study was to evaluate outcomes after RSA in patients with a history of preoperative opioid use and compare them with a control group without a history of preoperative opioid use.

METHODS

Sixty-eight RSAs performed for rotator cuff tear arthropathy (CTA) with a minimum of 2 years of follow-up were identified in a prospective shoulder arthroplasty registry. Thirty-two patients with a history of preoperative opioid use for shoulder pain were compared with a control group of 36 patients who did not use opioids preoperatively. Shoulder function scores and range of motion measurements were assessed preoperatively and at the final follow-up.

RESULTS

No differences were noted between the 2 groups in age, gender, duration of follow-up, depression, smoking, chronic back pain, diabetes, heart disease, or body mass index. Preoperative opioid use was associated with significantly lower preoperative shoulder function scores. Both groups significantly improved on all shoulder function scores and for range of motion measurements from the preoperative to the final follow-up assessment; however, the nonopioid group had significantly better outcomes. The magnitude of change between the groups from preoperatively to the final follow-up was nearly identical.

CONCLUSIONS

Improvements can be expected in patients with a history of preoperative opioid use; however, patients with preoperative opioid use have a lower preoperative baseline and should not expect to reach the same peak outcome scores after RSA as patients without a history of preoperative opioid use.

National utilization of reverse total shoulder arthroplasty in the United States

BACKGROUND

The substantial increase in the utilization of shoulder arthroplasty in the United States during the past decade is partly attributable to the growing acceptance of reverse shoulder arthroplasty (RSA). This study compared the national utilization of and indications for shoulder hemiarthroplasty, total shoulder arthroplasty (TSA), and RSA.

METHODS

The Nationwide Inpatient Sample was used to identify shoulder arthroplasty procedures performed in the United States in 2011. Indicating diagnoses, demographics, and hospital characteristics were identified for each shoulder arthroplasty procedure. Multivariable regression identified factors associated with long hospital stays.

RESULTS

An estimated 66,485 shoulder arthroplasty procedures were identified (33% RSA, 44% TSA, and 23% hemiarthroplasty). Common diagnoses for RSA were rotator cuff tear and arthritis (80%) and proximal humerus fracture (10%). TSA was performed for osteoarthritis in 93% of cases. Hemiarthroplasty was performed for osteoarthritis (45%) and proximal humerus fracture (38%). One quarter of proximal humerus fractures treated with arthroplasty received RSA compared with 69.8% that underwent hemiarthroplasty. Mortality occurred in 0.08% of patients with atraumatic diagnoses but in 0.53% of patients with proximal humerus fractures (P < .001). Older patients with comorbidities often had longer hospital stays, as did those with government insurance.

CONCLUSIONS

RSAs accounted for one third of all shoulder arthroplasty procedures in the United States in 2011. Whereas the majority of RSAs are performed for rotator cuff tear arthropathy, one quarter of proximal humerus fractures are treated with RSA, suggesting the strong uptake of this relatively new procedure in the United States.

Time-dependent changes after latissimus dorsi transfer: tenodesis or tendon transfer?

BACKGROUND

Transfer of the latissimus dorsi tendon to the posterosuperior part of the rotator cuff is an option in active patients with massive rotator cuff tears to restore shoulder elevation and external rotation. However, it is unknown whether this treatment prevents progression of cuff tear arthropathy.

QUESTIONS/PURPOSES

The purpose of this study was to determine whether the observed improvement in shoulder function in the early postoperative period with latissimus dorsi tendon transfer for irreparable rotator cuff tears will be permanent or will deteriorate in the midterm period (at 1-5 years after surgery).

METHODS

During a 6-year period, we performed 11 latissimus dorsi tendon transfers in 11 patients for patients with massive, irreparable, chronic tears of the posterosuperior part of the rotator cuff (defined as > 5 cm supraspinatus and infraspinatus tendon tears with Goutallier Grade 3 to 4 fatty infiltration on MRI), for patients who were younger than 65 years of age, and had high functional demands and intact subscapularis function. No patients were lost to followup; minimum followup was 12 months (median, 33 months; range, 12-62 months). The mean patient age was 55 years (median, 53 years; range, 47-65 years). Shoulder forward elevation, external rotation, and Constant-Murley and American Shoulder and Elbow Surgeons scores were assessed. Pain was assessed by a 0- to 10-point visual analog scale. Acromiohumeral distance and cuff tear arthropathy (staged according to the Hamada classification) were evaluated on radiographs.

RESULTS

Shoulder forward elevation, external rotation, Constant-Murley scores, and American Shoulder and Elbow Surgeons scores improved at 6 months. However, although shoulder motion values and Constant-Murley scores remained unchanged between the 6-month and latest evaluations, American Shoulder and Elbow Surgeons scores decreased in this period (median, 71; range, 33-88 versus median, 68; range, 33-85; p = 0.009). Visual analog scale scores improved between the preoperative and 6-month evaluations but then worsened (representing worse pain) between the 6-month and latest evaluations (median, 2; range, 0-5 versus median, 2; range, 1-6; p = 0.034), but scores at latest followup were still lower than preoperative values (median, 7; range, 4-8; p = 0.003). Although acromiohumeral distance values were increased at 6 months (median, 8 mm; range, 6-10 mm; p = 0.023), the values at latest followup (median, 8 mm; range, 5-10 mm) were no different from the preoperative ones (mean, 7 mm; range, 6-9 mm; p > 0.05). According to Hamada classification, all patients were Grade 1 both pre- and postoperatively, except one who was Grade 3 at latest followup.

CONCLUSIONS

The latissimus dorsi tendon transfer may improve shoulder function in irreparable massive rotator cuff tears. However, because the tenodesis effect loses its strength with time, progression of the arthropathy should be expected over time. Nevertheless, latissimus dorsi tendon transfer may help to delay the need for reverse shoulder arthroplasty for these patients.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

Isokinetic strength differences between patients with primary reverse and total shoulder prostheses: muscle strength quantified with a dynamometer

BACKGROUND

Range of motion after total shoulder arthroplasty is better than after reverse shoulder arthroplasty, however with similar clinical outcome. It is unclear if this difference can only be found in the different range of motion or also in the force generating capacity.

QUESTIONS

(1) are isokinetically produced joint torques of reverse shoulder arthroplasty comparable to those of total shoulder arthroplasty? (2) Does this force-generating capacity correlate with functional outcome?

METHODS

Eighteen reverse shoulder arthroplasty patients (71years (SD 9years)) (21 shoulders, follow-up of 21months (SD 10months)) were recruited, 12 total shoulder arthroplasty patients (69years (SD 9years)) (14 shoulders, follow-up of 35months (SD 11months)). Pre- and post-operative Constant-Murley scores were obtained; two isokinetic protocols (ab-/adduction and ex-/internal rotations) at 60°/s were performed.

FINDINGS

Twelve of 18 reverse shoulder arthroplasty patients generated enough speed to perform the test (13 shoulders). Mean ab-/adduction torques are 16.3Nm (SD 5.6Nm) and 20.4Nm (SD 11.8Nm). All total shoulder arthroplasty patients generated enough speed (14 shoulders). Mean ab-/adduction torques are 32.1Nm (SD 13.3Nm) and 43.1Nm (SD 21.5Nm). Only 8 reverse shoulder arthroplasty patients (9 shoulders) could perform ex-/internal rotation tasks and all total shoulder arthroplasty patients. Mean ex-/internal rotation torques are 9.3Nm (SD 4.7Nm) and 9.2Nm (SD 2.1Nm) for reverse shoulder arthroplasty, and 17.9Nm (SD 7.7Nm) and 23.5Nm (SD 10.6Nm) for total shoulder arthroplasty. Significant correlations between sub-scores: activity, mobility and strength and external rotation torques for reverse shoulder arthroplasty. Moderate to strong correlation for sub-scores: strength in relation to abduction, adduction and internal rotation torques for total shoulder arthroplasty.

INTERPRETATION

Shoulders with a total shoulder arthroplasty are stronger. This can be explained by the absence of rotator cuff muscles and (probably) medialized center of rotation in reverse shoulder arthroplasty. The strong correlation between external rotation torques and post-operative Constant-Murley sub-scores demonstrates that external rotation is essential for good clinical functioning in reverse shoulder arthroplasty.

Novel approaches to objectively assess shoulder function

BACKGROUND

The purpose of this study was to evaluate the effectiveness of existing technologies implemented in a novel manner to objectively capture upper extremity function.

MATERIALS AND METHODS

Patients scheduled to undergo reverse shoulder arthroplasty were recruited for the study. Functional limb use was measured with triaxial accelerometers worn in the subjects' natural living environment. Functional reach area was captured by 3-dimensional motion analysis testing as subjects were asked to circumduct their limb, reaching as far as possible in a circular manner. Statistical testing (α ≤ .05) was performed by paired t tests to identify differences between limbs.

RESULTS

There was no difference in functional limb activity between sides for the lower (P = .497) or upper arm (P = .918) for inactivity time. Mean activity was greater for the uninvolved limb compared with the involved limb (lower arm, P = .045; upper arm, P = .005). Low-intensity activity was greater for the involved arm compared with the uninvolved arm (lower arm, P = .007; upper arm, P = .015), whereas high-intensity activity was greater for the uninvolved arm (lower arm, P = .013; upper arm, P = .005). Radius of the functional reach area was greater for the uninvolved limb compared with the involved limb (P = .006).

CONCLUSIONS

Novel methods of capturing function were effective in discerning differences in side-to-side abilities among patients scheduled to undergo reverse shoulder arthroplasty. These testing procedures may be used to capture function across a spectrum of shoulder diseases. These objective data are invaluable in assessing the impact of disease and recovery after intervention and obtaining reimbursement from third-party payers.

Ultrasound of the pectoralis major muscle after reverse shoulder arthroplasty: a case report

Only a few reports exist in the literature for sonographic assessment of the pectoralis major muscle. Presented is a case of pectoralis major muscle atrophy as a cause of persistent internal rotation weakness diagnosed via ultrasound in a patient with multiple previous surgeries and contraindication to magnetic resonance imaging because of a shoulder implant. This patient's physical examination suggested an abnormal contour of the pectoralis major muscle on contraction, so he was referred for diagnostic ultrasound. The ultrasound was key to guiding the management of this patient because surgical repair of a torn pectoralis major muscle was planned if this was found. No pectoralis major tear or rupture was seen on ultrasound, but there was evidence of pectoralis major muscle atrophy. Accordingly, surgery was avoided and the patient was able to continue with his physical therapy program.

Hospital readmissions after primary shoulder arthroplasty

BACKGROUND

Although shoulder arthroplasty procedures are more frequently performed in the United States, there is insufficient information on outcome measures such as hospital readmission rates or factors for readmission after surgery.

METHODS

The State Inpatient Database from 7 different states was used to identify patients who underwent hemiarthroplasty, total shoulder arthroplasty (TSA), or reverse total shoulder arthroplasty (RTSA) from 2005 through 2010. The database was used to determine the 90-day readmission rate, causes of readmission, and risk factors for readmission. Multivariate modeling and a Cox proportional hazards model were used to measure factors and risk for readmission.

RESULTS

Included were 26,218 patients receiving shoulder arthroplasty, with an overall 90-day readmission rate of 7.3%. RTSA had the highest rate (11.2%), followed by hemiarthroplasty (8.2%) and TSA (6.0%; P < .001). Medical complications contributed to 82% of readmissions, and surgical complications contributed to 18%. Osteoarthritis was the most common medical diagnosis (11%), followed by deep venous thrombosis or pulmonary embolism (4.4%) and pneumonia (3.9%). Infection was the most common surgical cause of readmission (4.8%), followed by dislocation (4.6%). There was a stepwise increase in risk of readmission with increasing age. Patients with Medicaid insurance had more than a 50% greater risk of readmission than patients with Medicare. Procedures performed at medium-volume and high-volume hospitals showed lower risk of readmission than low-volume centers.

CONCLUSIONS

Patients undergoing RTSA had higher hospital readmission rates than those undergoing hemiarthroplasty or TSA, but most readmissions after shoulder arthroplasty were due to medical causes.

Latissimus dorsi tendon transfer for massive, irreparable posterosuperior rotator cuff tears: surgical technique

Massive rotator cuff tears remain a complex and challenging problem for both the patient and the surgeon. Although significant advancements in surgical techniques as well as technology for arthroscopic and mini-open rotator cuff repairs have been made, many massive tears result in failed repair with continued progressive tendon retraction and degeneration. In cases when primary tendon to bone healing is impractical, latissimus dorsi tendon transfer provides promising and reproducible clinical results. Herein, we present a latissimus tendon transfer surgical technique, a procedure we have used as a salvage operation for failed arthroscopic/mini-open primary rotator cuff repair.

Optimal positioning of the humeral component in the reverse shoulder prosthesis

INTRODUCTION

Total reverse shoulder arthroplasty is becoming more and more the standard therapeutic practice for glenohumeral arthropathy with massive lesions of the rotator cuff. The biomechanical principle of this prosthesis is represented by the reversion of the normal anatomy of the shoulder joint. This non-anatomical prosthesis leads to a medialization of the rotation centre of the glenohumeral joint and also to a distalization of the humeral head. All that causes a deltoid tension increasing so allowing a larger abduction of the arm. Main complications of the reverse shoulder prosthesis are due to the joint instability, the scapular notching and the wear of the polyethylene insert.

PURPOSE

The main goal of the present work is to study the effect of the positioning of the humeral component on the intrinsic stability of the reverse shoulder prosthesis. In particular, through finite element method simulations, the variation of the stability ratio of the shoulder joint has been calculated for both vertical and horizontal dislocating loads depending on the humeral stem version angle. Moreover, in order to estimate the wear of the polyethylene cup, some analyses have been developed to calculate the pressures on the polyethylene insert.

RESULTS

The obtained results demonstrate the dislocation of a shoulder prosthesis and the wear of the polyethylene insert can be prevented or limited by conveniently varying the version angle of the humeral component.

Hospital readmissions after surgical treatment of proximal humerus fractures: is arthroplasty safer than open reduction internal fixation?

BACKGROUND

With technologic advances such as locked periarticular plating, hemiarthroplasty of the humeral head, and more recently reverse total shoulder replacement, surgical treatment of proximal humerus fractures has become more commonplace. However, there is insufficient information regarding patient outcomes after surgery, such as the frequency of unplanned hospital readmissions and factors contributing to readmission.

QUESTIONS/PURPOSES

We measured (1) the frequency of unplanned hospital readmissions after surgical treatment of proximal humerus fractures, (2) the medical and surgical causes of readmission, and (3) the risk factors associated with unplanned readmissions.

METHODS

The State Inpatient Database from seven different states was used to identify patients who underwent treatment for a proximal humerus fracture with open reduction and internal fixation (ORIF), hemiarthroplasty of the humeral head, or reverse total shoulder arthroplasty from 2005 through 2010. The database was used to measure the 30-day and 90-day readmission rates and identify causes and risk factors for readmission. Multivariate modeling and a Cox proportional hazards model were used for statistical analysis.

RESULTS

A total of 27,017 patients were included with an overall 90-day readmission rate of 14% (15% for treatment with ORIF, 15% for reverse total shoulder arthroplasty, and 13% for hemiarthroplasty). The majority of readmissions were associated with medical diagnoses (75%), but treatment with ORIF was associated with the most readmissions from surgical complications, (29%) followed by reverse total shoulder arthroplasty (20%) and hemiarthroplasty (16%) (p < 0.001). Risk of readmission was greater for patients who were female, African American, discharged to a nursing facility, or had Medicaid insurance.

CONCLUSIONS

As the majority of unplanned hospital readmissions were associated with medical diagnoses, it is important to consider patient medical comorbidities before surgical treatment of proximal humerus fractures and during the postoperative care phase.

LEVEL OF EVIDENCE

Level III, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence.

Fluoroscopy-guided implantation of subacromial "biodegradable spacer" using local anesthesia in patients with irreparable rotator cuff tear

Treatment of massive rotator cuff tears can be challenging, especially when tears are considered irreparable or, when repaired, at significant risk of retear. A surgical technique is described using a biodegradable subacromial balloon-shaped spacer (InSpace; Ortho-Space, Caesarea, Israel) that, when implanted between the humeral head and acromion, permits smooth, frictionless gliding, supporting shoulder biomechanics. The specific insertion technique described herein is a simple procedure that can be performed in a day-care or outpatient setting with patients under local anesthesia, thus providing a treatment option for patients with multiple comorbidities complicating or contraindicating surgery, such as reverse arthroplasty under general anesthesia.

Functional evaluation of arthroscopic repair of rotator cuff injuries in patients with pseudoparalysis

Objective

to evaluate the functional result from arthroscopic repair of rotator cuff injuries in patients with pseudoparalysis, defined as incapacity to actively raise the arm above 90°, while complete passive elevation was possible.

Methods

we reevaluated 38 patients with a mean follow-up of 51 months (minimum of 24). We analyzed the pseudoparalysis reversion rate and the functional result obtained.

Results

according to the assessment criteria of the University of California in Los Angeles (UCLA), 31 (82%) patients had good and excellent results, two (5%) had fair results and five (13%) had poor results. The mean active elevation went from 39° before the operation to 139° after the operation (p < 0.05); the mean active lateral rotation went from 30° to 48° (p < 0.05) and the mean active medial rotation went from level L3 to T12 (p < 0.05).

Conclusion

arthroscopic repair of rotator cuff injuries produced good and excellent results in 82% of the cases and a statistically significant improvement of active range of motion, with reversion of the pseudoparalysis in 97.4% of the cases. It is therefore a good treatment option.

The influence of rotator cuff pathology on functional outcome in total shoulder replacement

Introduction:

Total shoulder replacement (TSR) is a reliable treatment for glenohumeral osteoarthritis. In addition to proper component orientation, successful arthroplasty requires accurate restoration of soft tissues forces around the joint to maximize function. We hypothesized that pathological changes within the rotator cuff on preoperative magnetic resonance imaging (MRI) adversely affect the functional outcome following TSR.

Materials and Methods:

A retrospective analysis of case notes and MRI of patients undergoing TSR for primary glenohumeral osteoarthritis over a 4-year period was performed. Patients were divided into three groups based upon their preoperative MRI findings: (1) normal rotator cuff, (2) the presence of tendonopathy within the rotator cuff, or (3) the presence of a partial thickness rotator cuff tear. Intra-operatively tendonopathy was addressed with debridement and partial thickness tears with repair. Functional outcome was assessed with the Oxford Shoulder Score (OSS), and quick disabilities of the arm, shoulder and hand score (quick-DASH).

Results:

We had a full dataset of complete case-notes, PACS images, and patient reported outcome measures available for 43 patients, 15 in group 1, 14 in group 2, and 14 in group 3. Quick-DASH and OSS were calculated at a minimum of 24 months following surgery. There was no statistically significant difference between the results obtained between the three groups of either the OSS (P = 0.45), or quick-DASH (P = 0.46).

Conclusions:

TSR is an efficacious treatment option for patients with primary glenohumeral osteoarthritis in the medium term, even in the presence of rotator cuff tendonopathy or partial tearing. Minor changes within the cuff do not significantly affect functional outcome following TSR.