Platform systems in shoulder arthroplasty

Hemiarthroplasty in Proximal Humerus Fractures: Does Modular Metaphyseal Stem Design Lead to Better Results? An Analysis of 24 Cases

Introduction

Anatomic hemiarthroplasty (aHA) is a treatment option for non-reconstructable constructable multifragment proximal humeral fractures that preserves range of motion. Our study aims to evaluate the radiographic and clinical outcomes of patients who received a modular aHA with anatomical sizing of the tubercle-bearing metaphyseal components.

Materials and Methods

The medical records of thirty-nine consecutive patients were reviewed. Patients were treated at a single institution with aHA as first-line treatment following a non-reconstructable constructable proximal humeral fracture. Tubercle resorption and cranialization of the aHA were analyzed using radiographic controls. Patient clinical function was assessed using the Constant Murley Score (CS).

Results

Twenty-four patients (62%) were available for clinical follow-up, with a mean CS of 54 points after a mean 56-month follow-up period. There was no significant difference in functional outcome on average between patients with healed tubercles (CS = 57) and resorbed tubercles (CS = 51). Radiographic follow-up was available in 33 patients (85%), demonstrating healed tubercles in 33% of the patients. Patients with resorbed tubercles had significant smaller acromio-humeral distances (AHD) than patients with healed tubercles (p = 0.043). A positive correlation was observed between greater AHD and increased constant scores (p = 0.022).

Conclusions

The final patient outcome measures demonstrated a positive correlation with a greater acromio-humeral distance and tubercle healing rates. However, the modular stem design with sizing of the metaphyseal components did not result in superior outcomes when compared with the literature.

Anatomical total shoulder arthroplasty revision to reverse shoulder arthroplasty using convertible glenoid: a systematic review of clinical and radiological outcomes

PURPOSE

The aim of the present systematic review is to collect all the available evidence regarding the clinical and radiological results of revision to reverse shoulder arthroplasty (RSA) of modular anatomic shoulder prostheses (TSA) using a convertible metal-backed glenoid (MBG).

METHODS

This study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Studies investigating revision of TSA to RSA utilizing a convertible MBG and reporting clinical and radiological outcomes were identified.

RESULTS

A total of five studies on the use of convertible modular glenoid component in the setting of TSA revision to RSA were finally included in the present systematic review. A total of 60 procedures were reported. Mean operative times was 65 min. Intraoperative complications included 3 cases of glenoid loosening. Only one case of dislocation was reported as postoperative complication. At mean follow-up of 32.3 months post-revision, no glenoid loosening was reported, VAS score decreased from 7.7 to 1.5, Constant Score increased from 24.8 to 57.6.

CONCLUSIONS

Revision to RSA after failed TSA using a convertible modular glenoid component was associated with a low rate of intraoperative and postoperative complications, low surgical time and led to good results in term of pain relieve and functional outcomes. Given the complexity and risk associated with revision of anatomic shoulder prosthesis having a convertible glenoid may help to simplify the procedure and improve clinical results.

Convertible-platform shoulder arthroplasty

Background

Shoulder arthroplasty has become an increasingly common procedure used to treat degenerative, inflammatory, and traumatic conditions of the glenohumeral joint. With a significant increase in primary anatomic and reverse total shoulder arthroplasty, revision procedures have likewise increased. Updates in shoulder arthroplasty have allowed for the convertibility of implants, which allows for the retention of both glenoid and humeral components during revision surgery. This review aims to highlight the epidemiology, indications, and outcomes of convertible-platform total shoulder arthroplasty procedures.

Methods

A review of the current literature surrounding convertible-platform shoulder arthroplasty was completed to highlight the advantages and disadvantages of commercially available instrumentation and implant systems as well as their outcomes.

Discussion

Leading causes of shoulder arthroplasty revision surgery include glenoid failure, implant instability, and rotator cuff dysfunction. Variations in implant design between inlay and onlay humeral components and metal-backed glenoid components are important considerations at the time of revision surgery. Advantages of convertible-platform systems include increased efficiency and decreased complications during revision procedures as well as shorter recovery, lower cost, and better functional outcomes. Limitations of convertible systems include poorly positioned components during the index procedure, excessive soft-tissue tensioning, and problems associated with metal-backed glenoid implants. Changes in arm length have also been documented. These findings indicate the benefit of additional research and design to improve the effectiveness and utility of convertible-platform shoulder arthroplasty systems.

Cement-within-cement technique in revision reverse shoulder arthroplasty: A systematic review of biomechanical data, and clinical outcomes

Background

The purpose of this research was to systematically review and summarize the existent literature on the use of the cement-within-cement technique for revision reverse shoulder arthroplasty (RSA).

Methods

We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The PubMed/Medline, Scopus, and EMBASE databases were searched for relevant studies. We included clinical studies in which patients underwent RSA revision using the cement-within-cement method for the humeral component, and studies that evaluated the biomechanical performance or described the surgical technique. The methodological risk of bias was assessed using the methodological index for non-randomized studies scale.

Results

The search yielded 516 records, of which two clinical and one biomechanical study met the inclusion criteria, involving 133 patients and 20 synthetic humeri. The intraoperative complication rate was 18%, all of which involved humeral fractures. The postoperative complication rate was 18% among 35 patients. The combined re-revision rate was 9%, with a reported humeral component survival rate of 100% at 2 years and 96% at 5 years. Periprosthetic fractures (1.5%) and humeral stem loosening (1.5%) led to re-revision surgeries in all cases. All studies reported improved patient-reported outcomes and range of motion. The biomechanical study demonstrated increased rotational stability in models that used larger humeral stems.

Conclusions

The cement-within-cement method is a viable option for revision RSA, showing positive outcomes in terms of stability, range of motion, and clinical functional scores. The complication rate is similar to that of other revision strategies; however, the prevalence of intraoperative humeral fractures may be higher. Nevertheless, future studies with larger sample sizes and longer follow-up periods are needed to refine patient selection, determine the efficacy of long-term use, and identify factors that may influence outcomes after the cement-within-cement revision technique. Further research on an optimized stem fixation strategy is needed to improve outcomes and reduce avoidable complications.

Level of evidence

Level IV, Systematic reviews.

Factors associated with humeral stem revision in anatomic to reverse total shoulder arthroplasty revision

BACKGROUND

Recent advances in implant technology have allowed for modular or platform humeral stem insertion during initial anatomic total shoulder arthroplasty (TSA). These systems allow for humeral stem retention during conversion to reverse TSA (RTSA). However, some patients still require humeral stem revision when undergoing revision to RTSA. The purpose of this study was to evaluate the association between patient-specific factors and radiographic parameters with humeral stem revision vs. retention during conversion from TSA to RTSA.

METHODS

Retrospective chart review was conducted for patients who underwent a revision TSA to RTSA between January 2010 and May 2022 at a single institution. Patients were included if their prosthesis included a convertible humeral stem. Patient demographic information, surgical details, and postoperative outcomes and complications were collected. Radiographic parameters were measured by 2 graders on radiographs taken prior to the revision procedure. The need for humeral stem revision and American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) scores (preoperative and 2 years) were also noted. Statistical analysis was performed using chi-square test for categorical variables and t test for continuous variables.

RESULTS

One hundred seven patients were included, with 52 undergoing humeral stem revision. Patients were revised an average of 51.0 ± 54 months after primary TSA. Younger patient age (63.6 vs. 68.5 years, P = .017) and use of a lateralized glenosphere (1.6 mm vs. 0.4 mm, P < .001) were significantly associated with need for humeral stem revision. Glenoid to humeral head cut distance (28.3 mm vs. 26.3 mm, P = .076) approached significant association with the need for humeral stem revision. All other measurements were not associated with the need for humeral stem revision. Improvement of ASES scores at 2 years' follow-up was higher in the nonrevised group (increase of 33.4 points) than the revision group (23.3), but this did not reach significance (P = .149). Estimated blood loss and surgical time were significantly higher in the stem revision group than the non-revised group (P = .048 and P < .001, respectively).

CONCLUSION

Younger patients and those receiving a lateralized glenosphere were more likely to undergo humeral stem revision during conversion from TSA to RTSA. Glenoid to the humeral head cut distance should be studied further as a potential indication for humeral stem revision, as it correlates with the space available for a revision implant. This information can guide surgeons with preoperative planning for a revision arthroplasty.

Proximal humerus fractures: A review of current practice

The management of proximal humeral fractures (PHF) remains controversial. Its incidence is increasing. Patients should be meticulously assessed clinically for co-morbidities and neuro-vascular injuries. Radiological investigation helps provide information on the fracture configuration and dislocations. Enhanced by 3-dimensional CT scanning, these further help in decision making and operative planning. PHF classifications have been demonstrated to have poor intra-observer and inter-observer reliability. Research has identified some radiographic predictive factors for humeral head ischaemia and likely failure of surgical fixation. The range of management options include non-operative treatment, operative fixation, intramedullary nailing and arthroplasty (hemiarthroplasty, reverse shoulder replacement). The majority of PHFs are stable injuries and non-operative management is usually successful. Some degree of malunion is readily tolerated especially by elderly patients. Surgical management of significantly displaced, unstable proximal humerus fractures should aim to stabilise the fracture adequately and provide satisfactory function for the long term. Management of the greater tuberosity is pivotal for the eventual outcome. When fixation may appear to be compromised by poor bone quality, likely poor function, age related rotator cuff degeneration or likely humeral head ischaemia clinicians may opt for arthroplasty. Successful hemiarthroplasty outcomes are dependent on sufficient healing of the tuberosity and recovery of the rotator cuff integrity. Reverse shoulder replacement can predictably deliver good functional outcomes for the shoulder in elderly patients, where rotator cuff dysfunction is suspected or as a revision procedure following failure of other surgical interventions. As opposed to hemiarthroplasty, which has shown a downward trend, there has been an increasing trend towards the use of reverse shoulder replacement in proximal humeral fractures. The management of PHFs should be patient specific, fracture specific and meet the functional demands and needs of the individual patient. The surgeon's skill set and clinical experience also plays an important role in the options of management available.

[Conversion of anatomic to reverse shoulder arthroplasty : Does it make sense?]

We can observe increasing numbers for the implantation of shoulder endoprostheses in developed industrial countries. This is accompanied by a certain number of revision surgeries. The conversion to reverse arthroplasty systems is by far the most common revision procedure. Depending on the primary implant and the individual situation, the surgical effort and consumption of resources can be substantial. Particularly favorable revision scenarios exist in the conversion of stemless primary implants that are part of a platform system and allow a partial exchange and easy conversion from anatomical to reverse implants.

Short Stems and Stemless Shoulder Arthroplasty: Current Concepts Review

Historically, the shoulder arthroplasty humeral component has been designed for the management of infections, tumours and fractures. In all these cases the stem was needed as a scaffold. Original humeral components were not developed for use in shoulder arthritis, so these designs and derivates had a long stem. The newest humeral implants innovations consist in shortening of the implant, or even removing the whole stem, to rely on stemless fixation at the level of the metaphysis. This implies the advantages of preserved bone stock, less stress shielding, eliminating the diaphyseal stress riser, easier implant removal at revision, and humeral component placement independent from the humeral diaphyseal axis. Nowadays, surgeons try to balance the need for a stable fixation of the humeral component with the potential need for revision surgery. Complications of revision shoulder arthroplasty are related to the need for removing a well-fixed humeral stem, the length of the procedure, and the need to treat severe bone loss.

Conversion of Hemiarthroplasty to Reverse Shoulder Arthroplasty with Humeral Stem Retention

The purpose of this study is to evaluate the mid-term clinical results of an ongoing case series on conversion reverse shoulder arthroplasty (RSA) with a modular prosthesis system. We included 17 elderly patients revised for failed hemiarthroplasty after proximal humeral fracture, of which 13 were converted using a modular reverse shoulder prosthesis. Four could not be converted due to overstuffing. For the conversion RSA, we determined the Constant score, American Shoulder and Elbow Surgeons Shoulder Score, visual analogue scale for pain and satisfaction, and range of motion preoperatively, at one year, and at the last follow-up. All measured clinical outcomes improved significantly at both follow-up time points (p < 0.05). The mean duration of surgery was 118.4 min (range: 80.0 to 140.0 min). We observed complications in three patients; these included one late infection and two aseptic stem loosenings. Modular shoulder arthroplasty is a suitable procedure for conversion RSA in elderly patients. All measured postoperative clinical outcomes improved significantly, the complication rate was acceptable, and no prosthesis-related complications occurred. Conversion RSA, although not feasible in every case, is a viable treatment option in the elderly, which can provide successful mid-term results.

Stem retention and survival in revision of anatomical convertible shoulder arthroplasty to reverse arthroplasty: a Dutch registry study

Background

Convertible stem designs allow for stem retention during revision from anatomical to reverse shoulder arthroplasty. In some cases conversion is not possible for example due to excessive soft tissue tensioning. In these cases a total revision is necessary. The primary aim of this Dutch registry study was to evaluate the unforeseen stem reversion percentages in revision of convertible anatomical shoulder arthroplasty to reverse shoulder arthroplasty.

Methods

Shoulder arthroplasties (n = 2834) performed between 2014 and 2016 registered in the Dutch Arthroplasty Registry were selected. In 2016 94% of primary arthroplasties and 92% of revision arthroplasties were registered in the database. Arthroplasties were selected on convertibility. Mean follow-up was 2.4 years. We analysed the number of revisions for convertible and non-convertible designs. Cases with obligatory revisions as periprosthetic joint infections, stem loosening and periprosthetic fractures were excluded. Kaplan-Meier analysis was used to calculate humeral stem survival. Multivariate cox-regression analysis was used to determine risk factors for stem revision.

Results

The majority of procedures (respectively 90.9 and 72.1% for the convertible and non-convertible group) concerned a conversion to reverse shoulder arthroplasty (p = .02). In the convertible group, the stem was retained in 29 out of 40 patients (72.5%). Overall implant survival was 94.5% after a mean follow-up of 2.4 years. Hemiartroplasty, fracture as primary indication, previous shoulder surgery and lower age were risk factors for revision.

Conclusions

Although convertible designs are gaining popularity due to their expected advantage in revision arthroplasty, surgeons should be aware that during a revision procedure in 27.5% of the patients an unforeseen stem revision is necessary.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04247-z.

Software simulations of changing offsets and thus soft tissue tension when revising anatomic to reverse total shoulder arthroplasty in convertible platform systems

BACKGROUND

Revision shoulder arthroplasty may involve the need to remove a well-fixed humeral stem. To avoid this, convertible platform systems have been introduced. The biomechanics of reverse total shoulder arthroplasty (rTSA) differs from anatomic shoulder arthroplasty (aTSA). The different humeral osteotomy and soft tissue tension may jeopardize the optimal results of the converted rTSA. The aim was to evaluate the radiographic parameters of soft tissue distraction when converting an aTSA to rTSA in a platform system and assess the capability of conversion without "over-stuffing" the shoulder in the "best-case scenario".

METHODS

Radiographic analysis of soft tissue distraction parameters: difference in acromio-humeral distance, difference in lateral humeral offset and difference in latero-inferior displacement were evaluated in aTSA and in the converted rTSA in six different implants. Image analysing software was used on 10 non-deformed osteoarthritic shoulder X-rays to simulate conversion.

RESULTS

The greatest increase in arm length was found for Tornier Ascend Flex (26.8 ± 3.6 mm) while the smallest increase was observed with Lima SMR (19.3 ± 4 mm). The humerus remained most lateralized with the Zimmer Anatomical/Inverse ( - 1.4 ± 2.9 mm) while Lima SMR ( - 15.8 ± 2.7 mm) was more medialized. The greatest increase in latero-inferior distance was found in the onlay systems. A group analysis of onlay rTSA showed an increase of 46% in arm length (p < 0.0001), 83% larger humeral offset (p < 0.0001) and 144% increase in latero-inferior distraction (p < 0.0001) when compared to inlay rTSA.

CONCLUSION

The conversion of aTSA to rTSA using a convertible platform system may lead to significant increase in radiographic parameters corresponding to soft tissue tension. This may alter the biomechanics, restrict the convertibility or jeopardize the optimal clinical outcome of rTSA even in the best-case scenario.

Reverse Total Shoulder Arthroplasty: Technique, Decision-Making and Exposure Tips

PURPOSE OF REVIEW

The goal of this review is to introduce surgical decision-making pearls for reverse shoulder arthroplasty and describe optimization of surgical exposure for reverse shoulder arthroplasty.

RECENT FINDINGS

While the technology of reverse shoulder replacement and the associated prosthetic options have expanded, the principles involved in successfully exposing the humerus and glenoid in arthroplasty remain the same. Reverse shoulder replacement should be considered in arthroplasty situations with rotator cuff disease, deformity, bone loss, and instability as part of the diagnosis. Optimal exposure in reverse shoulder arthroplasty can be obtained by (1) releasing deltoid adhesions, (2) removal of humeral osteophytes, (3) generous humeral head cuts, (4) thorough humeral and glenoid capsular release and (5) optimal glenoid retractor placement. Neuromuscular paralysis can also aid glenoid exposure.

Sex differences in complications and readmission rates following shoulder arthroplasty in the United States

Introduction

Shoulder arthroplasty (SA) procedures are increasingly performed in the United States. However, there is a lack of data evaluating how patient sex may affect perioperative complications. The purpose of this study was to evaluate sex-based differences in 30-day postoperative complication and readmission rates after SA.

Methods

Total SA and reverse SA cases between 2012-2016 were identified from the American College of Surgeons National Surgical Quality Improvement Program database. The 30-day complication rate, readmission rate, operation time, length of stay, and mortality were compared between women and men. Multivariable logistic regression analysis was performed to identify independent perioperative complications associated with patient sex.

Results

Of 12,530 SA cases, 6949 (55.4%) were female and 5499 (44.5%) were male. Compared with women, on average men were significantly younger, had lower body mass index, and were less likely to be functionally dependent, and less likely to have an American Society of Anesthesiologists score of 3+ (P < .001). Although overall complications and readmission rates between women and men were similar (3.4% vs. 3.7%, P = .489; 3.0% vs. 2.8%, P = .497), men were significantly less likely to develop urinary tract infections (UTIs; odds ratio [OR] 0.58, P = .032) and require transfusions (OR 0.49, P < .001) and had shorter lengths of stay (P < .001). However, men were significantly more likely to have a superficial surgical site infection (OR 2.63, P = .035) and 6.8 minute longer operating time (P < .001) compared with women.

Conclusion

Though the overall complication risk is similar between the sexes, their risk profiles are distinct. Men had decreased risk of UTI, blood transfusions, and shorter length of stay but increased risk of surgical site and longer operating time compared with women. This disparity should be discussed when counseling and risk-stratifying patients for SA.

Short-term results of a second generation anatomic short-stem shoulder prosthesis in primary osteoarthritis

INTRODUCTION

The aim of the study was to evaluate the short-term clinical results of anatomic total shoulder arthroplasty with a short-stem prosthesis in primary osteoarthritis.

MATERIALS AND METHODS

65 shoulders with a mean age of 70 years (range 47-85 years) were available for minimum follow-up of 24 months. Clinical outcome was determined by range of motion, Constant score (CS) age and sex-adjusted Constant score (CS%), and subjective shoulder value (SSV). The influence of six different factors (high bone adaptations, age > 65 years, female gender, dominant side, atrophy of the supraspinatus tendon ≥ grade 2, glenoid type B2/B3) on the clinical outcome was assessed.

RESULTS

At mean follow-up of 37 months (range 24-58 months), the CS improved from 36 ± 8 to 75 ± 12 (p < 0.001). The shoulder flexion (100° ± 21° to 159° ± 19°) as well as the external rotation (3° ± 11° to 43° ± 18°) improved significantly (p < 0.001). Three complications were noted (transient neuropraxia of the radial nerve, subjective instability, hematoma with superficial wound infection) leading to one revision surgery (wound debridement). No stem loosening was observed. High bone adaptation was present in 19 out of 65 shoulders (29%). The clinical outcome was not influenced by high bone adaptations (p ≥ 0.095). Age > 65 years (n = 44) and female gender (n = 38) were associated with worse clinical outcome (p ≤ 0.043).

CONCLUSIONS

In the short term, the clinical results of this anatomical short-stem shoulder prosthesis are encouraging. A low prevalence of high bone adaptations was found without any influence on the clinical outcome and stem loosening was not observed.

Mid-term results of anatomical total shoulder arthroplasty for primary osteoarthritis using a short-stemmed cementless humeral component

Aims

The aim of this study was to evaluate the clinical and radiological outcome of using an anatomical short-stem shoulder prosthesis to treat primary osteoarthritis of the glenohumeral joint.

Patients and Methods

A total of 66 patients (67 shoulders) with a mean age of 76 years (63 to 92) were available for clinical and radiological follow-up at two different timepoints (T1, mean 2.6 years, sd 0.5; T2, mean 5.3 years, sd 0.7). Postoperative radiographs were analyzed for stem angle, cortical contact, and filling ratio of the stem. Follow-up radiographs were analyzed for timing and location of bone adaptation (cortical bone narrowing, osteopenia, spot welds, and condensation lines). The bone adaptation was classified as low (between zero and three features of bone remodelling around the humeral stem) or high (four or more features).

Results

The mean Constant score improved significantly from 28.5 (sd 11.6) preoperatively to 75.5 (sd 8.5) at T1 (p < 0.001) and remained stable over time (T2: 76.6, sd 10.2). No stem loosening was seen. High bone adaptation was present in 42% of shoulders at T1, with a slight decrease to 37% at T2. Cortical bone narrowing and osteopenia in the region of the calcar decreased from 76% to 66% between T1 and T2. Patients with high bone adaptation had a significantly higher mean filling ratio of the stem at the metaphysis (0.60, sd 0.05 vs 0.55, sd 0.06; p = 0.003) and at the diaphysis (0.65 sd 0.05 vs 0.60 sd 0.05; p = 0.007). Cortical contact of the stem was also associated with high bone adaptation (14/25 shoulders, p = 0.001). The clinical outcome was not influenced by the radiological changes.

Conclusion

Total shoulder arthroplasty using a short-stem humeral component resulted in good clinical outcomes with no evidence of loosening. However, approximately 40% of the shoulders developed substantial bone loss in the proximal humerus at between four and seven years of follow-up. Cite this article: Bone Joint J 2018;100-B:603–9.