Short-stem uncemented primary reverse shoulder arthroplasty

Outcomes of a cementless onlay short stem reverse shoulder arthroplasty in elderly patients: a comprehensive analysis of clinical and radiological findings

OBJECTIVE

The objective of this study was to evaluate clinical and radiological outcomes of a short stem reverse shoulder prosthesis with metaphyseal fixation specifically in older patients.

METHODS

All patients, older than 70 years, submitted to a Reverse Shoulder Arthroplasty (RSA) using a cementless onlay short stem (Aequalis Ascend™ Flex Convertible Shoulder System (Stryker®)) from January 2017 to December 2021, with a minimum follow-up of 2 years, were included. Postoperative radiographs were assessed for stem loosening, subsidence, and varus-valgus tilt. Range of motion, visual analogue scale for pain, constant score, complication rate and revision rate were also analysed.

RESULTS

A total of 34 patients with a mean age of 75 years (range 71-83 years) were submitted to a cementless onlay short stem RSA with a Bone Increased Off-Set (BIO-RSA) construct. The mean follow-up period was 61 months (range 54-87). Significant improvements (p < 0.001) were observed for the constant score and range of motion from the preoperative state to final follow-up. One case exhibited a significant varus deviation (> 5˚) during the follow-up period. No case of stem loosening was identified. There was only one case of complication because of post-traumatic dislocation, but the stem didn't need revision.

CONCLUSION

Short stem RSA, even in patients older than 70 years, can yield a stable fixation with a good clinical and radiological outcome at short-medium term follow-up.

LEVEL OF EVIDENCE

Level III; Retrospective Study.

Medium-term clinical and radiographic outcomes of a cementless prosthesis with a 140° neck-shaft angle in reverse total shoulder arthroplasty

BACKGROUND

The design of humeral implants has evolved from the initial Grammont design, notably regarding the neck-shaft angle (NSA) and through the use of cementless prostheses. Stress shielding was frequently reported with cementless implants, the 2 main risk factors being humeral stem misalignment and high filling ratios. Our hypothesis was that standard length cementless stems with an NSA of 140° would facilitate good alignment with moderate filling ratios, thereby limiting stress shielding and ensuring good clinical outcomes.

METHODS

A single-center retrospective study was conducted of patients who underwent reverse total shoulder arthroplasty between January 2015 and August 2017, with at least 2 years' follow-up. Clinical evaluations included range of motion measurements and Constant and subjective shoulder values scores. Frontal alignment was assessed in terms of the angle (α) between axes of the stem and of the humerus. Filling ratios were measured in the metaphysis of the humerus, in the diaphysis, and at the distal end of the stem and considered excessive above 0.7. Stress shielding was evidenced radiographically by the observation of medial cortical narrowing, medial metaphysis thinning, lateral metaphysis thinning or under-the-baseplate osteolysis.

RESULTS

Eighty-two shoulders were included and 70 had radiographic follow-up data available. The mean patient age was 78 years and 63/81 patients (78%) were female. The mean follow-up time was 39 ± 7 months. The mean α angle was 1.4° ± 0.9° and was less than 5° in all cases. The mean metaphyseal, diaphyseal, and distal filling ratios were 0.61 ± 0.06, 0.70 ± 0.08, and 0.64 ± 0.09, respectively. The mean Constant score improved from 28 ± 11 preoperatively to 64 ± 14 at last follow-up. The mean subjective shoulder values score at last follow-up was 81 ± 12. Seventy-nine percent of patients (55/70) had at least 1 form of stress-shielding related, which were not associated with clinical outcomes, apart from lateral metaphysis thinning, which was associated with lower active anterior elevation (mean, 106° ± 30° vs. 126° ± 28°; P = .01) and lower Constant scores (mean, 56 ± 17 vs. 65 ± 14; P = .06).

CONCLUSION

The use of cementless reverse shoulder prostheses with a NSA of 140° was associated with good clinical outcomes at 2 years' follow-up. The prosthesis stem was correctly aligned with the humeral axis and the filling ratios were <0.7 in all cases. Stress-shielding was common but, apart from lateral metaphysis thinning, this had no impact on clinical outcomes.

Varus-valgus alignment of humeral short stem in reverse total shoulder arthroplasty: does it really matter?

BACKGROUND

The utilization of short humeral stems in reverse total shoulder arthroplasty has gained attention in recent times. However, concerns regarding the risk of misalignment during implant insertion are associated with their use.

METHODS

Eight fresh-frozen cadaveric shoulders were prepared for dissection and biomechanical testing. A bespoke humeral implant was fabricated to facilitate assessment of neutral, varus, and valgus alignments using a single stem, and 10° was established as the maximum permissible angle for misalignments. Shift in humerus position and changes in deltoid length attributable to misalignments relative to the neutral position were evaluated using a Microscribe 3DLx system. The impingement-free range of motion, encompassing abduction, adduction, internal rotation, and external rotation (ER), was gauged using a digital goniometer. The capacity for abduction was evaluated at maximal abduction angles under successive loading on the middle deltoid. A specialized traction system coupled with a force transducer was employed to measure anterior dislocation forces.

RESULTS

Relative to the neutral alignment, valgus alignment resulted in a more distal (10.5 ± 2.4 mm) and medial (8.3 ± 2.2 mm) translation of the humeral component, whereas the varus alignment resulted in the humerus shifting more superiorly (11.2 ± 1.3 mm) and laterally (9.9 ± 0.9 mm) at 0° abduction. The valgus alignment exhibited the highest abduction angle than neutral alignment (86.2°, P < .001). Conversely, the varus alignment demonstrated significantly higher adduction (18.4 ± 7.4°, P < .001), internal rotation (68.9 ± 15.0°, P = .014), and ER (45.2 ± 10.5°, P = .002) at 0° abduction compared to the neutral alignments. Anterior dislocation forces were considerably lower (23.8 N) in the varus group compared to the neutral group at 0°ER (P = .047). Additionally, abduction capability was markedly higher in varus alignment at low deltoid loads than the neutral alignment (5N, P = .009; 7.5 N, P = .007).

CONCLUSIONS

The varus position enhances rotational range of motion (ROM) but increases instability, while the valgus position does not significantly impact ROM or instability compared to the neutral position.

Bone mineral density around cementless short stems after reverse shoulder arthroplasty: changes over time and its relationship to stem positioning

Background

There are numerous reports of bone adaptation observed on plain radiography studies after the use of cementless short stems in reverse shoulder arthroplasty. However, reports on changes in bone mineral density (BMD) around the stem using dual-energy X-ray absorptiometry (DEXA) are prominently absent. In the present study, we measured BMD around the stem using DEXA and investigated changes over time from postoperative year 1 to year 2. Additionally, the relationship between BMD changes, filling ratio, and stem alignment was examined.

Methods

Forty-seven patients with short cementless stems who could be assessed via DEXA at 1-2 years postoperatively were included. After dividing the zones around the stem into 5, the BMD in each zone was measured, in addition to BMD changes and amount of change from postoperative year 1 to year 2. The relationship between filling ratio and stem alignment on postoperative plain radiography was assessed.

Results

A significant decrease in BMD in zone 3 was observed between postoperative year 1 and year 2 (P = .02). Regarding filling ratio and stem alignment, a negative correlation between valgus stem alignment and BMD change observed in zone 1 (r = -0.470, P < .01). In addition, stem valgus greater than 6° correlated with a significant decrease in BMD in zone 1. (P = .01). No significant differences were found in the other zones. Furthermore, there was no correlation between filling ratio and BMD change.

Conclusion

In reverse shoulder arthroplasty cementless short stems, changes that that occurred between postoperative year 1 to year 2 demonstrated a decrease in BMD in zone 3. In addition, a decrease in BMD in zone 1 was observed with a stem alignment of valgus 6° or higher, suggesting that stem alignment within valgus 6° is required to prevent a decrease in BMD.

Multiplanar analysis of proximal humerus anatomy of patients with rotator cuff arthropathy and relevance to reverse shoulder press-fit stems

Background

Short stems have become increasingly popular in reverse shoulder arthroplasty (RSA) due to their ability to preserve bone stock for revision surgery. However, short stems may be more at risk for malalignment or loosening, and commercially available stems have varied designs. The purpose of this study was to perform a multiplanar analysis of proximal humerus anatomy in patients with rotator cuff arthropathy to better define canal geometry and identify differences based on sex.

Methods

A retrospective review was performed of a consecutive series of patients undergoing RSA for rotator cuff arthropathy. A total of 117 patients were identified with preoperative computed tomography scans. Measurements were undertaken following multiplanar reconstruction of the computed tomography scans. Measured parameters included the following: transition point (TP), anteroposterior (AP) and mediolateral (ML) distances, intramedullary (IM) and bone diameter, and cortical thickness. The TP was defined as the distance from the periosteal border of the greater tuberosity to the level of the IM canal where the endosteal borders became parallel. Measurements started at the metaphysis, and then proceeded 25 and 50 mm distal to the metaphysis followed by 10 mm increments thereafter. Each level was compared to the level above with t tests in the overall cohort and separately by sex. Height was correlated to ML-AP difference and IM diameter with Pearson correlation coefficient. Potential stem sizes that extended 50, 60, 70, and 80 mm from the metaphysis were analyzed to record the percentage of patients in whom the stem would reach past the TP.

Results

The mean TP for all patients was 55.6 ± 7.4 mm (37.5-78.4) from the greater tuberosity, 53.3 ± 6.6 mm (37.5-67.0) in females and 58.1 ± 7.5 mm (41.9-78.4) in males. ML and AP distances and IM diameter became consistent at level 3 (mean, 83 mm distal to the greater tuberosity) in the overall cohort and in both sexes. Height positively correlated with IM diameter. Males had significantly larger IM diameters compared to females at all levels. Cortical thickness remained relatively consistent throughout the proximal humerus. A stem length of 70 mm would extend past the TP in 98% of patients.

Conclusion

Humeral implants in RSA with a stem of at least 70 mm in length would extend distally past the TP in the majority of cases regardless of sex. At this point, the canal's area remains consistent which would facilitate diaphyseal fixation if required.

How common is nerve injury after reverse shoulder arthroplasty? A systematic review

BACKGROUND

Nerve injury following reverse shoulder arthroplasty (RSA) is a known risk factor with wide ranging incidences reported. This systematic review evaluates the overall incidence of nerve injury following primary and revision RSA and summarizes the characteristics of the nerve injuries reported in the current literature.

METHODS

A systematic review was performed using separate database searches (Pubmed, Embase, Web of Science, Cochrane) following the PRISMA guidelines. Search criteria included the title terms "reverse shoulder," "reverse total shoulder," "inverted shoulder," and "inverted total shoulder" with publication dates ranging from 01/01/2010 to 01/01/2022. Studies that reported neurological injuries and complications were included and evaluated for primary RSA, revision RSA, number of nerve injuries, and which nerves were affected.

RESULTS

After exclusion, our systematic review consisted of 188 articles. A total of 40,146 patients were included, with 65% female. The weighted mean age was 70.3 years. The weighted mean follow-up was 35.4 months. The rate of nerve injury after RSA was 1.3% (510 of 40,146 RSAs). The rate of injury was greater in revision RSA compared to primary RSA (2.4% vs. 1.3%). Nerve injury was most common in RSAs done for a primary diagnosis of acute proximal humerus fracture (4.0%), followed by cuff tear arthropathy (3.0%), DJD (2.6%), and inflammatory arthritis (1.7%). Massive rotator cuff tears and post-traumatic arthritis cases had the lowest nerve injury rates (1.0% and 1.4%, respectively). The axillary nerve was the most commonly reported nerve that was injured in both primary and revision RSA (0.6%), followed by the ulnar nerve (0.26%) and median nerve (0.23%). Brachial plexus injury was reported in 0.19% of overall RSA cases.

CONCLUSION

Based on current English literature, nerve injuries occur at a rate of 1.3% after primary RSA compared with 2.4% after revision RSA. The most common nerve injury was to the axillary nerve (0.64%), with the most common operative diagnosis associated with nerve injury after RSA being acute proximal humerus fracture (4.0%). Surgeons should carefully counsel patients prior to surgery regarding the risk of nerve injury.

Reverse shoulder arthroplasty using an onlay humeral prosthesis, offset humeral tray, and augmented glenoid baseplate: surgical technique and review of the impact of prosthesis design on scapular fractures following reverse shoulder arthroplasty

Reverse total shoulder arthroplasty (RSA) has become the most utilized form of arthroplasty of the shoulder. Acromial stress fractures and scapular spine stress fractures are rare, yet well-recognized complications of RSA with ongoing studies identifying whether patient factors or prosthetic designs serve as risk factors. Specifically, it remains unclear if or how the position of the humeral tray (inlay or onlay) in RSA affects rates of periscapular fractures. The purpose of this article is to describe our technique for RSA using an onlay prosthesis, a variable-offset humeral tray, and an augmented glenoid baseplate, as well as to review the published results of acromial and scapular spine fractures after RSA based on humeral implant design.

Initial and 1-Year Radiographic Comparison of Reverse Total Shoulder Arthroplasty With a Short Versus Standard Length Stem

INTRODUCTION

In an effort to preserve bone, humeral stems in reverse total shoulder arthroplasty (RTSA) have gradually decreased in length. The purpose of this study was to compare the immediate postoperative radiographic appearance of short-length with standard-length RTSA stems.

METHODS

Patients who underwent RTSA using a press-fit standard-length or short-length humeral implant with a consistent geometry (Univers Revers or Revers Apex) were evaluated in a multicenter retrospective review. Initial postoperative radiographs were used to assess initial alignment and filling ratios. In addition, radiographs were evaluated for early signs of stress shielding and/or loosening. Clinical outcome scores and range of motion were also evaluated.

RESULTS

Overall, 137 short-length stems and 139 standard-length stems were analyzed. Initial radiographs demonstrated a significantly higher percentage of stems placed in neutral alignment in the short-stem group (95.6% vs 89.2%, P = 0.045). Similar metaphyseal filling ratios were seen between groups, but a significantly higher diaphyseal filling ratio was observed in the short-stem group (57% vs 34%, P < 0.001). Less calcar osteolysis (2.2% vs 12.9%; P = 0.001) and fewer overall number of radiographic changes (tuberosity resorption, lucencies, and subsidence) (0.7% vs 5.0%; P = 0.033) were seen with short stems compared with the standard-length stems.

CONCLUSION

RTSA with a short-stem humeral implant demonstrates excellent radiographic outcomes, including low rates of loosening and subsidence at 1 year, with less early calcar osteolysis compared with a standard-length stem.

LEVEL OF EVIDENCE

III (Case-control).

A 135° Short Inlay Humeral Stem Leads to Comparable Radiographic and Clinical Outcomes Compared to a Standard-Length Stem for Reverse Shoulder Arthroplasty

Background

Humeral stem length in reverse total shoulder arthroplasty (RTSA) has decreased in recent years in an attempt to preserve more bone and facilitate stem removal in the revision setting. The purpose of this study was to compare the clinical and radiographic outcomes of a short- to standard-length stem RTSA. The authors hypothesized that there would be no difference in radiographic or clinical outcomes at short-term follow-up.

Methods

Patients who underwent RTSA using a press-fit standard- or short-length humeral component with a consistent geometry (Univers Revers, or Revers Apex; Arthrex, Inc., Naples, FL, USA) were evaluated in a multicenter retrospective review. The minimum clinical follow-up was 2 years. Immediate postoperative radiographs were used to assess initial alignment and filling ratios. In addition, radiographs at 2 years were evaluated for signs of stress shielding and/or loosening. Clinical outcome scores and range of motion were evaluated at the final follow-up and compared between groups.

Results

A total of 220 patients with short-stem RTSA and 357 patients with standard-length stem RTSA were analyzed. There was no difference in baseline function between short- and standard-length stem patients. Patients in the short stem group had higher postoperative American Shoulder and Elbow Surgeons (84.6 vs. 80.8; P = .014) and Western Ontario Osteoarthritis of the Shoulder (86.5 vs. 82.7; P = .025). Patients in the short stem group also had greater postoperative active forward flexion (139° vs. 132°; P = .003) and internal rotation with the arm at 90° of abduction (43° vs. 32°; P < .001) than patients in the standard-length group. Radiographically, there was a higher metaphyseal (P = .049) and diaphyseal (P < .001) fill ratio in the short stem group, although there was no difference in postoperative alignment, radiographic signs of loosening, or revision for loosening between groups (all P > .05).

Conclusion

A short inlay stem leads to comparable radiographic findings and revision-free survival compared with a standard-length stem when placed with a press-fit technique for RTSA. Clinical outcomes are also equivalent or slightly improved with a short stem compared with a standard-length stem.

Using standard-length compactors to implant short humeral stems in total shoulder arthroplasty: A cadaver study of humeral stem alignment

Background

Short-stem implants in shoulder arthroplasty were recently developed and reported clinical outcomes are good. However, radiological analysis often reveals humeral stem misalignment in the frontal plane, along with high filling ratios that can lead to proximal bone remodeling under stress shielding. The aim of this cadaveric study was to test whether using compactors for standard-length (> 100 mm) stems to implant short (< 100 mm) stems reduces the risk of stem misalignment without compromising in terms of a higher filling ratio.

Methods

In a cadaveric study, twenty short stems were implanted using instrumentation for standard-length stems. Alignment and filling ratios were evaluated on anteroposterior radiographs for both the compactors and the stems. The angular deviations (α) from the humeral axis of the compactors and the short stems were measured. Misalignment was defined as |α| > 5°. Metaphyseal and diaphyseal filling ratios were calculated and defined as either high (≥ 0.7) or low (< 0.7).

Results

The median angular deviations of the compactors and the short stems were respectively 1.6° (range, 0.03 to 5.9°) and 1.3° (range, 0.3 to 9.6°). Nineteen of the 20 compactors (95%) and 17/20 short stems (85%) were correctly aligned. The proportions of correctly aligned compactors and stems were not significantly different (95% CI, −0.33 to 0.11; Z-test of proportions p = .60), and the respective angular deviations were significantly correlated (Spearman ρ = .60, p = 0.006). The diaphyseal and metaphyseal filling ratios of the compactors and the stems were all low.

Conclusions

In this series of 20 implants in cadavers, the narrow short humeral stems implanted with compactors for standard-length stems were correctly aligned with the humeral axis. This approach may be a way to achieve both correct frontal alignment and low filling ratios.

Clinical results and radiological bony adaptations on a cementless short-stem prosthesis - A comparative study between anatomical and reverse total shoulder arthroplasty

INTRODUCTION

Although the use of short stem and stemless shoulder prosthesis is trending, the surgical outcome may vary due to varying biomechanics. Objectives were to evaluate and compare the short-term clinical results and radiological changes between anatomical total shoulder arthroplasty (TSA) and reverse TSA (rTSA) with a short-stem humeral design.

HYPOTHESIS

There is no clinical and radiological difference between TSA and rTSA using a short-stem humeral design.

METHODS

This retrospective study included 66 patients who underwent TSA and rTSA (33 patients each) with a minimum 2-year follow-up. Radiographic findings, including preoperative Tingart cortical index (TCI), postoperative filling ratios of metaphysis (FRmet) and diaphysis (FRdia), bone adaptations, and osteolysis around the humeral stem at the immediate postoperative period, and the most recent follow-up were measured. Pre and postoperative Constant-Murley score, subjective shoulder value (SSV), and complications were noted.

RESULTS

At a mean follow-up of 27 (range 24-50) months, FRmet was significantly higher in rTSA group than the TSA group (0.65 vs. 0.60, p=0.009). Bone resorption was similar in both groups (p=0.76) and was correlated to a lower TCI value of<2.9mm (p=0.02). Despite significant clinical improvement in individual groups, the comparison between groups was non-significant (p>0.05). Negative correlation was observed between TCI and total clinical score (p=0.045) in TSA group, active external rotation (p=0.019), activity (p=0.005), SSV (p=0.008) and total score (p=0.025) in rTSA group. Radiographic changes were not influenced by patient characteristics and clinical results (p>0.05).

CONCLUSION

Although no radiographic difference was observed between TSA and rTSA, better short-term clinical results observed with the usage of the short-stem humeral design prosthesis are encouraging.

LEVEL OF EVIDENCE

III; Retrospective cohort study.

Are short press-fit stems comparable to standard-length cemented stems in reverse shoulder arthroplasty? A prospective, randomized clinical trial

BACKGROUND

The literature comparing humeral implants in reverse shoulder arthroplasty is sparse. With minimal supporting literature, there has been a trend away from standard-length cemented humeral implants to press-fit stems and, recently, to shorter-stem implants. It is known that early implant migration, within the first 2 years postoperatively, is predictive of later implant loosening and possible revision surgery. Therefore, the purpose of this study was to compare clinical outcomes and implant migration between cemented standard-length humeral stems and press-fit short stems using model-based radiostereometric analysis.

METHODS

After a power analysis, 41 shoulders were prospectively randomized to receive either a cemented standard-length or press-fit short humeral stem for primary reverse shoulder arthroplasty between July 2017 and June 2019. Following surgery, participants were imaged with stereo radiographs acquired at 6 weeks (baseline), 3 months, 6 months, 1 year, and 2 years. Migration of the humeral stem at each time point was compared with baseline, with differences in migration between cohorts assessed using a mixed-effects model with the Bonferroni test for multiple comparisons. Patient-reported outcome measures (Subjective Shoulder Value; American Shoulder and Elbow Surgeons shoulder score; Simple Shoulder Test score; Disabilities of the Arm, Shoulder and Hand score; and Constant score) were also compared.

RESULTS

At 6 months (P = .025), 1 year (P = .004), and 2 years (P = .001) postoperatively, press-fit short stems migrated significantly more than cemented stems along the superior-inferior translation axis; in addition, they showed greater total translation at 2 years (P = .003). Mean total translation (± standard deviation) at 2 years was 0.4 ± 0.2 mm and 1.0 ± 1.1 mm for the cemented and press-fit cohorts, respectively. Mean migration between the 1- and 2-year time points was minimal for both stem fixation groups along all axes (<0.1 mm and 0.6°). There was no difference in active range of motion, pain, or validated outcome measures between the cohorts at 2 years (P ≥ .170).

CONCLUSION

This randomized clinical trial shows that press-fit short humeral stems subside substantially more than standard-length cemented stems but ultimately achieve stability from 1 year through 2 years. Conversely, no significant differences were observed in clinical outcomes between cohorts.

Problems, complications, and reinterventions in 4893 onlay humeral lateralized reverse shoulder arthroplasties, a systematic review: part II-problems and reinterventions

BACKGROUND

Several modifications to the original Grammont reverse shoulder arthroplasty (RSA) design have been proposed to prevent distinctive issues, such as both glenoid and humeral lateralization. The aim of this systematic review was to determine rates of problems, complications, reoperations, and revisions after onlay lateralized humeral stem RSA, hypothesizing that these are design related.

METHODS

This systematic review was performed in accordance with the PRISMA statement guidelines. A literature search was conducted (1 January 2000 to 14 April 2020) using PubMed, Cochrane Reviews, Scopus, and Google Scholar, employing several combinations of keywords: "reverse shoulder arthroplasty," "reverse shoulder prosthesis," "inverse shoulder arthroplasty," "inverse shoulder prosthesis," "problems," "complications," "results," "outcomes," "reoperation," and "revision."

RESULTS

Thirty-one studies with 4893 RSA met inclusion criteria. The 892 postoperative problems and 296 postoperative complications represented overall problem and complication rates of 22.7% and 7.5%, respectively. Forty-one reoperations and 63 revisions resulted, with overall reoperation and revision rates of 1.7% and 2.6%, respectively.

CONCLUSIONS

Problem, complication, and reintervention rates proved acceptable when implanting a high humeral lateralization stem RSA. The most frequent problem was scapular notching (12.6%), and the most common postoperative complication was scapular stress fracture (1.8%). An overall humeral complication rate of 1.9% was identified, whereas no humeral fractures or stem loosening were reported with short stems. Infections (1.3%) were the most common reason for component revision, followed by instability (0.8%).

LEVEL OF EVIDENCE

Systematic review IV.

Problems, complications, and reinterventions in 4893 onlay humeral lateralized reverse shoulder arthroplasties: a systematic review (part I-complications)

Background

Several modifications to the original Grammont reverse shoulder arthroplasty (RSA) design have been proposed to prevent distinctive issues, such as both glenoid and humeral lateralization. The aim of this systematic review was to determine rates of problems, complications, reoperations, and revisions after onlay lateralized humeral stem RSA, hypothesizing that these are design related.

Methods

This systematic review was performed in accordance with the PRISMA statement guidelines. A literature search was conducted (01.01.2000–14.04.2020) using PubMed, Cochrane Reviews, Scopus, and Google Scholar employing several combinations of keywords: “reverse shoulder arthroplasty,” “reverse shoulder prosthesis,” “inverse shoulder arthroplasty,” “inverse shoulder prosthesis,” “problems,” “complications,” “results,” “outcomes,” “reoperation,” “revision.”

Results

Thirty-one studies with 4893 RSA met inclusion criteria. The 892 postoperative problems and 296 postoperative complications represented overall problem and complication rates of 22.7% and 7.5%, respectively. Forty-one reoperations and 63 revisions resulted, with an overall reoperation rate of 1.7% and overall revision rate of 2.6%.

Conclusions

Problem, complication, and reintervention rates proved acceptable when implanting a high humeral lateralization stem in RSA. The most frequent problem was scapular notching (12.6%), and the most common postoperative complication was scapular stress fracture (1.8%). An overall humeral complication rate of 1.9% was identified, whereas short stems reported no humeral fractures or stem loosening. Infections (1.3%) proved to be the most common reason for component revision, and instability had a complication rate of 0.8%.

Level of evidence

Systematic review IV

Primary reverse shoulder replacement with a short stem: A systematic literature review

Background

Total shoulder arthroplasty implant designs have continued to evolve over the years. One recent change has been the shortening of the humeral component to preserve bone stock and to facilitate revision surgery. Despite promising clinical results, radiographic bone adaptions occur frequently in short-stem total shoulder arthroplasty, and limited data exist on short-stem reverse shoulder arthroplasty (RSA). The purpose of this systematic review was to provide an overview about the functional and radiographic outcomes after an uncemented short-stem RSA, as well as identify areas of clinical importance that are underreported in the current literature.

Methods

A systematic review of the literature was performed in accordance with the PRISMA guidelines using PubMed, Cochrane Central Register of Controlled Trials, and EMBASE. Clinical outcome studies reporting on short-stem RSA outcomes with evidence level I-IV were included. Demographics, clinical and radiological outcomes, as well as complications and revision data were systematically analyzed and described.

Results

Ten studies, published between 2014 and 2019, reporting on 555 shoulders with a mean follow-up of 32 months (range, 20-99.6 months) met the inclusion criteria. For all studies cuff tear arthropathy was the main indication for RSA (36%), followed by primary osteoarthritis (20%). Clinical outcome was reported in nine of ten studies, with range of motion improving in all studies. Six of the seven studies that used the Constant score (CS) demonstrated significant improvement (27.9 points to 69.3 points in weighted means). All studies reported on radiographic changes and bone adaptions. Among these, scapular notching was the most commonly observed (60 out of 327 cases, 18%) but without any described implication on clinical outcomes. No stem loosening was recorded at any final follow-up. A total of 63 complications (12.9%) were reported, with scapula fractures being the most commonly reported complication. Revision surgery was necessary in 24 cases (4.9%).

Conclusion

Good clinical results, comparable with long-stem RSAs, are reported at short-term follow-up for short-stem RSAs. Humeral bone adaptions occur frequently but aseptic stem loosening is not a matter of concern at short-term follow-up. An area of clinical importance that is under-reported is the relation between filling ratio and stem alignment in short-stem RSA.

RSA, TSA and PyC hemi-prostheses: comparing indications and clinical outcomes using a second-generation modular short-stem shoulder prosthesis

INTRODUCTION

The goal of this study was to provide an insight into the clinical results after modular short-stem shoulder arthroplasty for various indications.

MATERIALS AND METHODS

A consecutive cohort study of 76 patients followed up for 23-55 (mean 31.4) months. 23 anatomical (TSA), 32 reverse (RSA) and 21 hemi-prostheses with a pyrocarbon head (PyC), using a modular short stem with proximal porous coating were implanted. Range of motion, pain and Constant score (CS) were recorded. Comparisons of pre- vs postoperative outcomes, between prosthesis types and indications, were made.

RESULTS

All prosthesis types brought about a significant improvement (p < 0.05) in all measured outcomes. TSA had a significantly higher increase in the CS than PyC and RSA (p = 0.002 and 0.003, respectively). TSA produced superior gains in all ROM compared with RSA (p < 0.02). RSA brought about significantly smaller improvements in internal rotation than TSA and PyC (p = 0.0001 and 0.008, respectively). TSA had greater pain relief than PyC (p = 0.02). TSA with Walch A glenoids seemed to improve more than type B in the CS. PyC patients with Walch B glenoids improved more than Walch A (p = 0.03). When implanted due to Osteoarthritis (OA), PyC had a comparable final outcome to TSA (p = 0.95), although the preoperatively worse TSA patients had a greater improvement in the CS (p = 0.026). The outcome of RSA did not differ between indications, but Walch A glenoids tended to improve more.

CONCLUSIONS

Using a second-generation short-stem shoulder prostheses, TSA achieves the best clinical improvements overall, especially for OA with a Walch A glenoid. Despite refixation of the subscapularis tendon in all cases, RSA has inferior internal rotation than TSA and PyC, suggesting a mechanical limitation. OA, a Walch B glenoid and arthritis caused by instability seem to be ideal indications when considering PyC.

Prospective, Blinded, Randomized Controlled Trial of Stemless Versus Stemmed Humeral Components in Anatomic Total Shoulder Arthroplasty: Results at Short-Term Follow-up

BACKGROUND

Stemless humeral components for anatomic total shoulder arthroplasty (aTSA) have several reported potential benefits compared with stemmed implants. However, we are aware of no Level-I, randomized controlled trials (RCTs) that have compared stemless implants with stemmed implants in patients managed with aTSA. We sought to directly compare the short-term clinical and radiographic outcomes of stemless and stemmed implants to determine if the stemless implant is noninferior to the stemmed implant.

METHODS

We performed a prospective, multicenter, single-blinded RCT comparing stemless and short-stemmed implants in patients managed with aTSA. Range-of-motion measurements and American Shoulder and Elbow Surgeons (ASES), Single Assessment Numeric Evaluation (SANE), and Constant scores were obtained at multiple time points. Device-related complications were recorded. Radiographic evaluation for evidence of loosening, fractures, dislocation, or other component complications was performed. Statistical analysis for noninferiority was performed at 2 years of follow-up for 3 primary end points: ASES score, absence of device-related complications, and radiographic signs of loosening. All other data were compared between cohorts at all time points as secondary measures.

RESULTS

Two hundred and sixty-five shoulders (including 176 shoulders in male patients and 89 shoulders in female patients) were randomized and received the allocated treatment. The mean age of the patients (and standard deviation) was 62.6 ± 9.3 years, and 99% of the shoulders had a primary diagnosis of osteoarthritis. At 2 years, the mean ASES score was 92.5 ± 14.9 for the stemless cohort and 92.2 ± 13.5 for the stemmed cohort (p value for noninferiority test, <0.0001), the proportion of shoulders without device-related complications was 92% (107 of 116) for the stemless cohort and 93% (114 of 123) for the stemmed cohort (p value for noninferiority test, 0.0063), and no shoulder in either cohort had radiographic signs of loosening. Range-of-motion measurements and ASES, SANE, and Constant scores did not differ significantly between cohorts at any time point within the 2-year follow-up.

CONCLUSIONS

At 2 years of follow-up, the safety and effectiveness of the stemless humeral implant were noninferior to those of the stemmed humeral implant in patients managed with aTSA for the treatment of osteoarthritis. These short-term results are promising given the potential benefits of stemless designs over traditional, stemmed humeral components.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Subsidence of Uncemented Short Stems in Reverse Shoulder Arthroplasty-A Multicenter Study

BACKGROUND

The radiological phenomenon of subsidence following the implantation of uncemented short-stem reverse prostheses (USSP) has not yet been described. The purpose of this study was to describe the rate and potential risk factors for subsidence. We hypothesized that subsidence may be a frequent finding and that a subsidence of >5 mm (mm) is associated with an inferior clinical outcome.

METHODS

A total of 139 patients with an average age of 73 ± 9 years were included. The clinical and radiological outcome was evaluated at a minimum follow-up (FU) of 12 months.

RESULTS

No humeral component loosening was present at a mean FU of 18 (range, 12-51) months. Mean Constant Score (CS) and Subjective Shoulder Value (SSV) improved significantly from 34.3 ± 18.0 points and 37.0 ± 19.5% preoperatively to 72.2 ± 13.4 points and 80.3 ± 16.5% at final FU (p < 0.001). The average subsidence of the USSP was 1.4 ± 3.7 mm. Subsidence of >5 mm was present in 15 patients (11%). No association between a subsidence >5 mm and CS or SSV was found (p = 0.456, p = 0.527). However, a subsidence of >5 mm resulted in lower strength at final FU (p = 0.022). Complications occurred in six cases (4.2%), and the revision rate was 3.5% (five cases).

CONCLUSIONS

Although subsidence of USSP is a frequent radiographic finding it is not associated with loosening of the component or a decrease in the clinical outcome at short term FU.

LEVEL OF EVIDENCE

Level 4, retrospective study.

The modern reverse shoulder arthroplasty and an updated systematic review for each complication: part II

Background

Globally, reverse shoulder arthroplasty (RSA) has moved away from the Grammont design to modern prosthesis designs. The purpose of this study was to provide a focused, updated systematic review for each of the most common complications of RSA by limiting each search to publications after 2010. In this part II, the following were examined: (1) instability, (2) humerus/glenoid fracture, (3) acromial/scapular spine fractures (AF/SSF), and (4) problems/miscellaneous.

Methods

Four separate PubMed database searches were performed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Overall, 137 studies for instability, 94 for humerus/glenoid fracture, 120 for AF/SSF, and 74 for problems/miscellaneous were included in each review, respectively. Univariate analysis was performed with chi-square and Fisher exact tests.

Results

The Grammont design had a higher instability rate vs. all other designs combined (4.0%, 1.3%; P < .001), and the onlay humerus design had a lower rate than the lateralized glenoid design (0.9%, 2.0%; P = .02). The rate for intraoperative humerus fracture was 1.8%; intraoperative glenoid fracture, 0.3%; postoperative humerus fracture, 1.2%; and postoperative glenoid fracture, 0.1%. The rate of AF/SSF was 2.6% (371/14235). The rate for complex regional pain syndrome was 0.4%; deltoid injury, 0.1%; hematoma, 0.3%; and heterotopic ossification, 0.8%.

Conclusions

Focused systematic reviews of recent literature with a large volume of shoulders demonstrate that using non-Grammont modern prosthesis designs, complications including instability, intraoperative humerus and glenoid fractures, and hematoma are significantly reduced compared with previous studies. As the indications continue to expand for RSA, it is imperative to accurately track the rate and types of complications in order to justify its cost and increased indications.

The modern reverse shoulder arthroplasty and an updated systematic review for each complication: part I

Background

Globally, reverse shoulder arthroplasty (RSA) has moved away from the Grammont design to modern prosthesis designs. The purpose of this 2-part study was to systematically review each of the most common complications of RSA, limiting each search to publications in 2010 or later. In this part (part I), we examined (1) scapular notching (SN), (2) periprosthetic infection (PJI), (3) mechanical failure (glenoid or humeral component), and (4) neurologic injury (NI).

Methods

Four separate PubMed database searches were performed following Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Overall, 113 studies on SN, 62 on PJI, 34 on mechanical failure, and 48 on NI were included in our reviews. Univariate analysis was performed with the χ² or Fisher exact test.

Results

The Grammont design had a higher SN rate vs. all other designs combined (42.5% vs. 12.3%, P < .001). The onlay humeral design had a lower rate than the lateralized glenoid design (10.5% vs. 14.8%, P < .001). The PJI rate was 2.4% for primary RSA and 2.6% for revision RSA. The incidence of glenoid and humeral component loosening was 2.3% and 1.4%, respectively. The Grammont design had an increased NI rate vs. all other designs combined (0.9% vs. 0.1%, P = .04).

Conclusions

Focused systematic reviews of the recent literature with a large volume of RSAs demonstrate that with the use of non-Grammont modern prosthesis designs, complications including SN, PJI, glenoid component loosening, and NI are significantly reduced compared with previous studies. As the indications for RSA continue to expand, it is imperative to accurately track the rates and types of complications to justify its cost and increased indications.

Outcomes of reverse shoulder arthroplasty using a short stem through a superolateral approach

BACKGROUND

Reverse shoulder arthroplasties have progressed in recent decades to become the most popular type of arthroplasty. Short stems with metaphyseal fixation have been developed to preserve bone stock and facilitate possible revision. Accurate positioning of these implants can be challenging using the superolateral approach.

OBJECTIVE

This study aimed to evaluate the clinical and radiologic results of reverse short-stem arthroplasties using a superolateral approach with a minimum of 2 years' follow-up.

METHODS

Between January 2015 and December 2016, a total of 76 patients underwent reverse shoulder arthroplasty surgery (79 shoulders) using a short uncemented humeral stem for shoulder arthritis with irreparable rotator cuff tear. Arthroplasties for post-traumatic osteoarthritis were excluded. Functional outcomes were assessed using Constant Score, American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), visual analog scale (VAS), and range of motion. Radiographic analysis was used to evaluate component loosening, implant position, and implant filling ratio.

RESULTS

The mean age was 70.8 years. At a mean of 38.8-month follow-up, there were significant improvements in Constant score (44.2 to 87.9, P < .001), ASES score (36.2 to 84.3, P < .001), and VAS score (6.8 to 0.4, P < .001). Forward flexion improved from 89°to 131°(P < .001), and external rotation improved from 25° to 36°(P < .001). No evidence of periprosthetic loosening was visible. Mean varus of the humeral stem was 1°(±6°). The mean glenoidal inclination was 98°(±7°), which corresponds to a lower tilt of 8°. The average filling ratio was between 50% and 60% in both the metaphysis and the diaphysis.

CONCLUSION

The clinical results obtained in this study were satisfying, with a significantly low complication rate. Hence, short-stem reverse shoulder arthroplasty using a superolateral approach, while taking particular care to protect the deltoid, remains our method of choice.

Proximal humeral bony adaptations with a short uncemented stem for shoulder arthroplasty: a quantitative analysis

Background

Short uncemented stems have recently been proposed as an alternative to classic long stems for shoulder arthroplasty. The early results are promising, but bony adaptations of the proximal humerus have been reported. The aim of this study was to quantify these phenomena using the Ascend Flex stem and to determine the risk factors.

Materials and methods

In a retrospective, single-center study, 183 shoulder arthroplasties were evaluated at 2-year follow-up. All patients underwent clinical evaluations preoperatively and at last follow-up. Radiographs were obtained preoperatively, postoperatively, and at last follow-up. Four types of bony adaptations were analyzed: medial cortical narrowing (MCN), medial metaphysis thinning (MMT), lateral metaphysis thinning (LMT), and under-the-baseplate osteolysis. The risk factors were analyzed in a multivariate model.

Results

MCN was found in 72.6% of cases and was severe (>50%) in 4.4%. MMT was found in 46.4% of cases and was severe in 3.3%. LMT was found in 9.8% of cases and was severe in 2.8%. The risk factors for MCN were the distal filling ratio, osteoporosis, and female sex, whereas MMT and LMT were only influenced by stem axis deviation. Under-the-baseplate osteolysis was found in 34.4% of cases. No influence of bony adaptations on the clinical outcomes was observed. We found no complications related to the stem or to stem loosening.

Conclusion

The radiographic evolution was satisfactory at mid-term follow-up. Bony adaptations seemed to be limited phenomena, without any observed consequence. Avoiding excessive filling and axis deviation may limit these phenomena.

Humeral Stem Loosening Following Reverse Shoulder Arthroplasty: A Systematic Review and Meta-Analysis

BACKGROUND

Aseptic stem loosening following reverse shoulder arthroplasty (RSA) is an uncommon complication. The timing and the factors contributing to aseptic stem loosening remain poorly understood.

METHODS

We performed a systematic review that identified 75 articles; 65 of the included articles were case series (Level-IV evidence), 8 were cohort studies (7 Level III, 1 Level II), and 2 were prospective randomized controlled trials (Level I). A meta-analysis of 1,660 cemented and 805 uncemented RSA stems was performed. We compared the rates of aseptic stem loosening, humeral radiolucent lines, and revision for stem loosening (1) between cemented and uncemented stems in cohorts with short and long mean follow-up periods (<5 and ≥5 years) as well as in all cohorts combined, and (2) among different etiological subgroups.

RESULTS

Aseptic stem loosening occurred more commonly in the cohort with long compared with short follow-up time (2% versus 0.8%, p = 0.01). When comparing cemented with uncemented stems, there was no significant difference in the rates of aseptic stem loosening or revision for stem loosening in either the short or long-term follow-up groups. Humeral radiolucent lines were more common with cemented compared with uncemented stems (15.9% versus 9.5%, p = 0.002). Analyzed by etiology, the highest rate of aseptic stem loosening occurred in the tumor subgroup (10.8%), followed by RSA as a revision procedure after a failed arthroplasty (3.7%). No stems in the acute fracture or fracture sequelae subgroups developed aseptic stem loosening.

CONCLUSIONS

Aseptic stem loosening occurred more commonly in cohorts with longer follow-up. There were no differences in the rates of aseptic stem loosening or revision for stem loosening between cemented and uncemented stems. Patients treated with RSA following excision of proximal humeral tumors and RSA as a revision procedure after a failed arthroplasty were at greater risk of aseptic stem loosening.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Reverse Total Shoulder Arthroplasty: Implant Design Considerations

PURPOSE OF REVIEW

Our understanding of the reverse total shoulder arthroplasty (RTSA) has grown exponentially since Grammont first introduced his design in 1985. There are a multitude of implant-related variables to consider when performing RTSA. The purpose of this article is to provide a review of these design considerations.

RECENT FINDINGS

Current literature demonstrates that the traditional Grammont prosthesis has over 90% survivorship at 10 years. Despite these promising results, there have been concerns raised over the significant rate of scapular notching observed. As a result, the traditional RTSA design has been modified to minimize this complication and maximize impingement-free motion. Modern RTSA designs with a cementless, curved, short-stemmed eccentric onlay humeral component combined with a large, lateralized glenosphere placed in 10° of inferior tilt with > 3.5 mm of inferior overhang have been found to provide excellent results. However, all implant design features must be considered on a case-by-case basis to optimize outcome for each patient. Humeral and glenoid implant design variables have evolved as the biomechanics of RTSA have been further elucidated. Consideration of these variables allows the surgeon to maximize joint efficiency, improve impingement-free range of motion, decrease the risk of scapular notching, preserve bone stock, and minimize the risk of instability.

Does proximal porous coating in short-stem humeral arthroplasty reduce stress shielding?

CONTEXT

Short-stem humeral designs in shoulder arthroplasty have been introduced recently. A retrospective cohort study was conducted to determine if newer proximal porous titanium coating in humeral short stems produced clinical and radiologic improvements.

METHOD

Short-stem humeral implants (Tornier Ascend, Wright Medical) were used in 46 anatomical total shoulder replacements from October 2012 to December 2015. Clinical and radiologic measures were analyzed at one- and two-year follow-up.

RESULTS

Nineteen shoulders received earlier grit blasted stems (Ascend Monolithic), and 27 shoulders received the later stems with proximal titanium porous coating (Ascend Flex). At two-year follow-up, radiographic changes and stress shielding were similar. Medial cortical thinning were more frequently observed in Monolithic (18 of 19) compared to Flex stems (19 of 27) on the PA films, though this was not statistically significant (P = 0.061). Clinical outcome scores improved regardless of the stem type used and independent of the radiologic adaptations on plain films. One participant with the Ascend Flex developed glenoid component failure and rotator cuff tear and was subsequently revised.

DISCUSSION

Clinical and radiological outcomes are similar in both short-stem designs. Proximal titanium porous coating may reduce medial calcar cortical thinning but it does not prevent it.

KEY MESSAGE

When compared to similarly designed uncoated grit-blasted stems, proximally porous coated humeral short stems produced similar clinical and radiological results. The proximal titanium porous coating may reduce medial cortical thinning.

Mid-term radiological results of a cementless short humeral component in anatomical and reverse shoulder arthroplasty

AIMS

Shoulder arthroplasty using short humeral components is becoming increasingly popular. Some such components have been associated with relatively high rates of adverse radiological findings. The aim of this retrospective review was to evaluate the radiological humeral bone changes and mechanical failure rates with implantation of a short cementless humeral component in anatomical (TSA) and reverse shoulder arthroplasty (RSA).

PATIENTS AND METHODS

A total of 100 shoulder arthroplasties (35 TSA and 65 RSA) were evaluated at a mean of 3.8 years (3 to 8.3). The mean age at the time of surgery was 68 years (31 to 90). The mean body mass index was 32.7 kg/m² (17.3 to 66.4).

RESULTS

Greater tuberosity stress shielding was noted in 14 shoulders (two TSA and 12 RSA) and was graded as mild in nine, moderate in two, and severe in three. Medial calcar resorption was noted in 23 shoulders (seven TSA and 16 RSA), and was graded as mild in 21 and moderate in two. No humeral components were revised for loosening or considered to be loose radiologically. Nine shoulders underwent reoperation for infection (n = 3), fracture of the humeral tray (n = 2), aseptic glenoid loosening (n = 1), and instability (n = 3). No periprosthetic fractures occurred.

CONCLUSION

Implantation of this particular short cementless humeral component at the time of TSA or RSA was associated with a low rate of adverse radiological findings on the humeral side at mid-term follow-up. Our data do not raise any concerns regarding the use of a short stem in TSA or RSA. Cite this article: Bone Joint J 2019;101-B:610-614.

Postoperative radiographic findings of an uncemented convertible short stem for anatomic and reverse shoulder arthroplasty

BACKGROUND

Several short-stemmed press-fit humeral components have been developed in recent years for anatomic total shoulder arthroplasty (TSA) as well as reverse shoulder arthroplasty (RSA). Varying radiographic outcomes have been reported, with some studies reporting concerning rates of aseptic loosening. This study analyzed the radiographic findings of a press-fit convertible short-stemmed humeral component in both TSA and RSA.

METHODS

There were 150 anatomic TSAs (group 1) and 77 RSAs (group 2) analyzed radiographically at a minimum follow-up of 2 years postoperatively. Plain radiographs were reviewed for stem loosening, alignment, signs of stress shielding, and the filling ratio.

RESULTS

At final follow-up, 49% of group 1 and 65% of group 2 had no evidence for radiographic changes. In those with radiographic changes, low bone adaptions were found in 83% and high adaptions in 17% in both groups. Larger stem sizes with higher filling ratios were associated with high radiographic adaptions in both groups (P = .02). The overall filling ratios were higher in group 2 (P = .002). Cortical contact of the stem led to higher bone adaptions (P = .014).

CONCLUSIONS

The short humeral component analyzed in this study showed encouraging survival rates without aseptic loosening. Radiographic changes are associated with a higher filling ratio and cortical contact of the stem. Surgeons should aim to achieve fixation with the minimal required canal filling to minimize radiographic changes with the uncemented humeral component used in this study.

Long - Term survivorship and clinical and radiological follow - up of the primary uncemented Delta III reverse shoulder prosthesis

Background

Purpose of this study was to evaluate the long - term survivorship and clinical and radiological results of a primary reverse total shoulder arthroplasty (RTSA) performed with uncemented stems.

Methods

From 2001 until 2006 61 primary uncemented RTSAs were implanted, which were included in a Kaplan-Meier survival analysis. Range of motion, functional scores and radiological follow - up was obtained. 27 patients were available for follow - up. Mean follow-up was 9.2 years (SD 2.4).

Results

Mean cumulative survival was 82.4% (95% CI: 50.7-94.6%) of the total construct and 98.3% (CI: 88.8-98.8%) of the uncemented humeral stem after 12.5 years. Five revisions occurred (8.2%). Mean anteflexion improved from 69.3 to 111.9° (p < 0.0001), lateral elevation from 65.9 to 101.3° (p < 0.0001), Constant-Murley score from 39.1 to 66.9 (p < 0.0001), Simple Shoulder Test from 1.5 to 7.1 (p < 0.0001), and VAS-pain from 65.5 to 6.6 at final follow-up (p = 0.0003). Scapular notching was present in 94.1% of the patients.

Conclusions

The present study shows that the long-term clinical results of the primary Delta III RTSA seem very encouraging and survivorship of, in particular, its uncemented humeral stem is good.

Value comparison of humeral component press-fit and cemented techniques in reverse shoulder arthroplasty

BACKGROUND

Press-fit humeral fixation for reverse shoulder arthroplasty (RSA) has been shown to have loosening rates and outcomes similar to a cemented technique; however, increased value has not been reported. The purpose of this study was to determine whether the press-fit technique could improve the value of RSA using the procedure value index (PVI).

METHODS

Primary RSA patients with complete hospitalization cost data, preoperative and minimum 2-year postoperative Simple Shoulder Test (SST) scores, and postoperative satisfaction were included. The PVI was calculated as improvement in the SST score (in units of minimal clinically important difference) divided by total cost and normalized. Itemized cost data were obtained from hospital financial records and categorized. Radiographic complications, infections, and revisions were noted. Comparisons were made between the press-fit and cemented RSA cohorts.

RESULTS

A total of 176 primary RSA patients (83 cemented and 93 press fit) met the inclusion criteria (mean follow-up period, 44.6 months). Surgical indications (except failed rotator cuff repair), baseline SST scores, and demographic characteristics were similar. The calculated minimal clinically important difference for the SST score was 3.98. The average PVI was significantly greater in the press-fit cohort (1.51 vs 1.03, P < .001), representing a 47% difference. SST score improvement was not significantly different (P = .23). However, total hospitalization costs were significantly lower for the press-fit cohort ($10,048.89 vs $13,601.14; P < .001).

CONCLUSION

Use of a press-fit technique led to a 47% increase in value over a cemented technique. This appeared to be a function of decreased total costs rather than increased outcome scores.

Short Humeral Stems in Shoulder Arthroplasty

Since the introduction of shoulder arthroplasty by Neer in 1974, the design of not only the glenoid component but also the humeral component used in shoulder arthroplasty has continually evolved. Changes to the design of the humeral component include a gradually disappearing proximal fin; diversified surface finishes (such as smooth, grit-blasted, and porous coating); a more contoured stem from the originally straight and cylindrical shape; and the use of press-fit uncemented fixation as opposed to cemented fixation. Despite the evolution of the humeral component for shoulder arthroplasty, however, stem-related complications are not uncommon. Examples of stem-related complications include intraoperative humeral fractures, stem loosening, periprosthetic fractures, and stress shielding. These become much more common in revision arthroplasty, where patients are associated with further complications such as surgical difficulty in extracting the humeral component, proximal metaphyseal bone loss due to stress shielding, intraoperative humeral shaft fractures, and incomplete cement removal. Physicians have made many attempts to reduce these complications by shortening the stem of the humeral component. In this review, we will discuss some of the limitations of long-stem humeral components, the feasibility of replacing them with short-stem humeral components, and the clinical outcomes associated with short-stemmed humeral components in shoulder arthroplasty.

Clinical and radiographic outcomes after total shoulder arthroplasty with an anatomic press-fit short stem

BACKGROUND

There is limited information assessing outcomes after total shoulder arthroplasty (TSA) with a press-fit short stem. The purpose of this study was to evaluate early clinical and radiographic outcomes and complications after TSA with an anatomic press-fit short stem.

METHODS

We identified 118 TSAs completed with press-fit short stem and minimum 2-year follow-up; 85 of these patients had a grit-blasted (GB) short stem placed, whereas 33 patients had short stems with proximal porous coating (PPC). Shoulder function scores, active mobility measurements, and radiographs were assessed.

RESULTS

The average age at surgery was 66.7 years, with average follow-up of 3 years. Significant improvements were noted for all shoulder function scores and active mobility measurements from the preoperative state to final follow-up (P < .001). There was no stem loosening in any patients with minimum 2-year follow-up; however, 3 female patients with GB stems had gross loosening of their humeral components before 1 year, 2 requiring revision. Radiolucent lines around the humeral component were found in 5.9% without evidence of loosening. Osseous resorption at the medial cortex was noted in 9.3%. Of patients with PPC stems, no patients were observed to have radiolucent lines compared with 8.2% in the GB group (P = .09).

CONCLUSION

TSAs with anatomic press-fit short stem showed significant clinical improvements from the preoperative state to final short-term follow-up, with few complications and minimal radiographic changes. Lack of PPC may contribute to early loosening in patients with poor bone quality. The authors now use a short stem with PPC.

Radiographic changes and clinical outcomes associated with an adjustable diaphyseal press-fit humeral stem in primary reverse shoulder arthroplasty

BACKGROUND

Press-fit humeral fixation in reverse shoulder arthroplasty (RSA) has become increasingly popular; however, radiographic analysis of these stems is limited. We aimed to evaluate the radiographic and clinical outcomes of an adjustable diaphyseal press-fit humeral stem in primary RSA.

METHODS

We conducted a retrospective review of 232 primary RSAs in 219 patients performed by a single surgeon using this system. Radiographic outcomes were evaluated in patients with at least 2 years of radiographic follow-up. Standardized postoperative digital radiographs were analyzed for loosening, osteolysis, and stress shielding. Clinical outcomes in patients who also had complete clinical data sets were evaluated at the most recent follow-up.

RESULTS

Radiographic evidence of loosening was identified in 1 RSA (0.4%) associated with deep infection. Aseptic loosening was not observed. No stems were identified as being at high risk for loosening. Internal stress shielding was observed proximal to the coated diaphyseal component in 226 shoulders (97.4%). This finding was often visible at 3 months (92.7%) and predictably progressed on subsequent radiographs. Progression beyond the 2-year period was rarely seen (4.4%). No external stress shielding or osteolysis was observed. Thirty-six complications occurred in 33 patients (15.1%). At an average follow-up of 36.6 months, significant improvements were identified in all measured clinical outcomes (P < .001).

CONCLUSION

Predictable fixation is achieved using an adjustable diaphyseal press-fit humeral system in primary RSA. Internal stress shielding is commonly observed but does not appear to compromise quality of fixation or clinical outcomes.

Use of a shorter humeral stem in revision reverse shoulder arthroplasty

BACKGROUND

The purpose of this study was to examine the outcomes of revision reverse arthroplasty using short bone-preserving humeral components in revising a long-stemmed component.

METHODS

During a 7-year period, 39 patients who underwent revision reverse shoulder arthroplasty using the long to short humeral component technique were included. The mean age was 72 years. Prior implants used in the primary setting included anatomic (n = 26), hemiarthroplasty (n = 11), and reverse (n = 2).

RESULTS

At a follow-up of 3 years (2-5), 5 shoulders (13%) required revision surgery, including 1 for a periprosthetic humerus fracture and 4 for glenoid component loosening. The survival free of revision for any reason and revision for humeral disease was 84% and 94%, respectively. One patient experienced a nondisplaced greater tuberosity fracture at 18 months postoperatively that healed without operative intervention. There were no dislocations or infections. Overall, patients experienced excellent overall improvements in their pain levels and shoulder motion (P < .001), with a postoperative 91% satisfaction rate as well as postoperative American Shoulder and Elbow Surgeons score of 68 and Simple Shoulder Test score of 6.7. At most recent radiographic follow-up, 1 (5%) patient had grade 3 humeral lucency.

CONCLUSIONS

Preserving bone stock through conversion to a shorter reverse humeral stem in the revision setting is a reasonable option with good short- to intermediate-term results and low rates of humeral complications. Using the shorter stem components provides adequate stability and high rates of humeral component ingrowth.

Short Stem Reverse Total Shoulder Arthroplasty Periprosthetic Type A Fracture

Alterations have been made over the years to the standard reverse total shoulder arthroplasty (RTSA) prosthetic components in an effort to decrease adverse events; this has led to the advent of a short humeral stem prosthesis. To the authors' knowledge, there are no reports describing the complication of a traumatic periprosthetic Wright and Cofield classification type A fracture with use of a short metaphyseal humeral stem component for RTSA. The authors describe a 49-year-old woman with this pathology who was treated with open reduction and internal fixation using a proximal humerus locking plate, unicortical and bicortical screw fixation, and a cerclage wire construct without the need to violate the shoulder joint or revise components. Three months postoperatively, she was instructed to begin active range of motion in physical therapy. At 13 months postoperatively, the patient rated her pain level at an average 5 of 10 in severity, with active assisted scaption to 125°, external rotation to 15°, and internal rotation to L5. Radiographs at this time revealed a well-healed fracture. This not only indicates the previously unreported occurrence of such a complication pattern, which was thought rare with the advent of the short humeral RTSA stem, but also provides a viable intraoperative strategy for open reduction and internal fixation with a proximal humerus locking plate, unicortical and bicortical screw fixation, and a cerclage wire construct without the need to violate the shoulder joint. [Orthopedics. 2017; 40(4):e721-e724.].

Proximal ingrowth coating decreases risk of loosening following uncemented shoulder arthroplasty using mini-stem humeral components and lesser tuberosity osteotomy

BACKGROUND

Mini-stem humeral component (MSHC) use during total shoulder arthroplasty (TSA) provides bone preservation and ease of revision. MSHCs rely solely on proximal metaphyseal fixation; some early reports have demonstrated an unacceptably high rate of early loosening. To our knowledge, no study analyzing the effect of proximal porous coating on MSHCs has been performed.

METHODS

We performed a retrospective review of consecutive patients who underwent anatomic TSA using coated or uncoated MSHCs with minimum 2-year follow-up. Postoperative radiographs were assessed for risk of or frank stem loosening, subsidence, and presence of radiolucencies. Range of motion, outcome scores (visual analog scale pain, American Shoulder and Elbow Surgeons, and Single Assessment Numeric Evaluation), and any complications were noted.

RESULTS

We analyzed 68 shoulders with a mean follow-up of 27.3 months (range, 24-50 months). Of these, 34 had proximal coating and 34 were uncoated. In the coated group, no stems loosened, 1 (2.9%) subsided, and 7 (20.6%) developed radiolucencies. In the uncoated group, 1 stem (2.9%) became aseptically loose (requiring revision after 26 months), 7 (20.6%) were judged at risk of loosening (2 because of subsidence), and 15 (44.1%) developed radiolucencies. There was also an increased risk of proximal medial humeral radiolucencies among uncoated MSHCs. There were no significant differences in final range of motion or outcome scores.

CONCLUSION

MSHC use is appropriate for TSA, achieving desired pain relief and functional improvement. Overall, component loosening appears uncommon at early follow-up; however, uncoated stems appear to be at greater risk of loosening and developing radiolucencies. Selecting an MSHC with proximal porous coating may decrease the risk of implant-related complications.

Primary reverse shoulder arthroplasty in patients aged 65 years or younger

BACKGROUND

Reverse total shoulder arthroplasty (RTSA) has classically been reserved for patients older than 65 years with rotator cuff arthropathy, pseudoparalysis, and severe pain. This investigation assessed outcomes in a consecutive series of patients aged 65 and younger undergoing primary RTSA.

METHODS

There were 63 patients (67 shoulders; 40 women, 27 men) with a mean age of 60 years (range, 50-65 years). Indications were cuff tear arthropathy (CTA) in 51, severe glenohumeral arthritis in 15, and osteonecrosis in 1. The primary end point was revision-free implant survival. Pain scale, motion, strength, and radiographic outcomes were also studied.

RESULTS

At a mean follow-up of 3 years (range, 2-8 years), the 2-year and 5-year revision-free survival was 99% and 91%, and reoperation-free survival was 97% and 90%, respectively. Complications occurred in 9%. Smoking increased the risk for revision, reoperation, and complications (P < .03). Patients experienced improvements in pain (P < .0001), active abduction (57.5° vs. 132.4°, P < .0001), and active external rotation (20.1° vs. 39.4°, P < .001). At the most recent follow-up, 90% patients were satisfied with their result, and 85% felt they were better or much better than before surgery. There was an 18% incidence notching, 3% incidence of dislocation, and no loosening.

CONCLUSIONS

At both 2 and 5 years, RTSA is a reliable operation in patients aged younger than 65 years. Patients gain significant improvements in pain level, range of motion, and strength, without a large number of early failures. Long-term follow-up is needed to understand late component mechanical problems and loosening.

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.

Functional and radiologic outcomes of uncemented reverse shoulder arthroplasty in proximal humeral fractures: cementing the humeral component is not necessary

BACKGROUND

Our aim was to determine the radiologic and functional outcomes of patients who underwent reverse shoulder arthroplasty (RSA) for proximal humeral fractures and to assess whether the uncemented humeral components put them at risk for early loosening and failure.

METHODS

Thirty-three patients were identified in our hospital database (January 2004-December 2012). Twenty patients were assessed using American Shoulder Elbow Surgeons (ASES) score, Constant Shoulder Score (CSS), and the Oxford Shoulder Score (OSS). Up-to-date shoulder radiographs were evaluated for evidence of radiologic loosening.

RESULTS

The mean follow-up period was 3.0 years (range, 2.5-7.8 years), and the mean age at the time of surgery was 76.5 years (range, 62-87 years). The mean ASES was 75.9 of 100 (range, 55-98.3), with a mean visual analog scale pain score of 2 of 10. The mean OSS was 42.5 of 48 (range, 35-48), and the mean CSS was 54.1 of 100 (range, 32-72). Upon radiographic assessment of the humeral component, 6 patients (30%) had 3 or more lucent zones, and 12 patients (60%) had a lucent zone measuring more than 2 mm in width; however, only 2 patients (10%) had 3 or more lucent zones measuring 2 mm or more in width and were identified as "at risk of loosening." No patients had tilt or subsidence of the humeral prosthesis.

CONCLUSIONS

Our study demonstrated satisfactory functional and radiologic outcomes of patients compared with other studies, suggesting that RSA is a good management option for elderly patients with these fractures. The uncemented nature of the humeral component did not result in early loosening or failure.

Total shoulder arthroplasty: are the humeral components getting shorter?

Each generation of total shoulder arthroplasy has improved on the previous. The newest humeral component innovation is shortening the humeral component or eliminating the stem entirely to rely on stemless fixation in the humeral metaphysis. This offers theoretical advantages of preserved bone stock, less stress shielding, eliminating the diaphyseal stress riser, ease of stem removal at revision, and humeral head placement independent from the humeral shaft axis. There are a number of short term cohorts that have shown low complication rates and outcomes similar to previous generations of stemmed humeral components. Longer term and better designed studies are needed in order for short stems and stemless components to become the standard of care.

The incidence of radiographic aseptic loosening of the humeral component in reverse total shoulder arthroplasty

BACKGROUND

The reverse total shoulder arthroplasty (RTSA) has been used in the treatment of complex shoulder problems. The incidence of aseptic loosening of the humeral component has not been previously reported.

METHODS

This is a multicenter, retrospective, blinded, case-control radiographic review of 292 patients to determine the rate of humeral stem loosening. There were 177 cemented and 115 press-fit humeral components. Radiographs were critiqued for radiolucent lines adjacent to the humeral stem based on the method described by Gruen et al.

RESULTS

The overall rate of loosening was 0.74%. No radiographic loosening occurred in the press-fit group (115 stems). In the cemented group (177 stems), 2 shoulders (1.18%) were identified with radiographically loose stems. No loosening occurred in the press-fit group. No statistically significant difference was found in humeral stem loosening when the press-fit group and the cemented group were compared (P = .198).

DISCUSSION

Our study indicates the cemented or press-fit RTSA system will result in a low incidence of radiolucent lines and radiographic loosening. Compared with historical survivorship of conventional anatomic total shoulder arthroplasty, RTSA shows a lower rate of radiographic stem loosening at a mean of 38.46 months.

CONCLUSIONS

The RTSA has a low incidence of humeral stem loosening at midterm. These results underscore the importance of careful selection of patients to provide the benefits of this surgical technique. Press-fit fixation may provide a lower risk to stem loosening.

Reverse total shoulder replacement for nonunion of a fracture of the proximal humerus

Patients with pain and loss of shoulder function due to nonunion of a fracture of the proximal third of the humerus may benefit from reverse total shoulder replacement. This paper reports a prospective, multicentre study, involving three hospitals and three surgeons, of 35 patients (28 women, seven men) with a mean age of 69 years (46 to 83) who underwent a reverse total shoulder replacement for the treatment of nonunion of a fracture of the proximal humerus. Using Checchia’s classification, nine nonunions were type I, eight as type II, 12 as type III and six as type IV. The mean follow-up was 51 months (24 to 99). Post-operatively, the patients had a significant decrease in pain (p < 0.001), and a significant improvement in flexion, abduction, external rotation and Constant score (p < 0.001), but not in internal rotation. A total of nine complications were recorded in seven patients: six dislocations, one glenoid loosening in a patient who had previously suffered dislocation, one transitory paresis of the axillary nerve and one infection.

Reverse total shoulder replacement may lead to a significant reduction in pain, improvement in function and a high degree of satisfaction. However, the rate of complications, particularly dislocation, was high.

Cite this article: Bone Joint J 2014;96-B:1239–43.