Total shoulder arthroplasty with an augmented component for anterior glenoid bone deficiency

Eccentric reaming is superior to augmented components in B2 glenoids: a biomechanical study

BACKGROUND

Primary glenohumeral arthritis is typically associated with glenoid retroversion and posterior bone loss. Glenoid component fixation remains a weak link in the survivorship of anatomical total shoulder arthroplasty, particularly in the B2 glenoid. The aim of this study was to compare biomechanical properties of 2 glenoid preparation techniques in a B2 glenoid bone loss model.

METHODS

This was a biomechanical cyclic loading study. Thirty sawbone shoulder models were generated from a computed tomography scan of a scapula with a B2 glenoid and 15° retroversion. The study consisted of 2 groups with 'low' correction (A groups), 2 groups with 'high' correction (B groups), and a control. Group A1 consisted of a 7° eccentric ream and a standard component; group A2 consisted of a 15° posteriorly augmented glenoid component (7° correction); group B1 consisted of a 12° anterior ream and standard component; group B2 used a 25° posteriorly augmented component (12° correction); group C (control) consisted of a standard component inserted in retroversion with no correction. Mechanical stability testing was performed through cyclic loading and resulting displacement was determined at 1, 10, 1000, 10,000, 50,000, and 100,000 cycles to assess for loosening.

RESULTS

A total of 26 samples were included in the analysis, all reaching 100,000 cycles. Displacement increased significantly from baseline to 100,000 cycles in all groups (P < .05). At 100,000 cycles, the B1 group (1.4 mm ± 0.19) had significantly less displacement then the A2 (2.0 mm ± 0.29) and B2 (2.2 mm ± 0.49) (P = .0.005) groups. There were no significant differences in translational forces between any of the groups at 100,000 cycles.

CONCLUSIONS

Our data demonstrated that the use of higher degree posteriorly augmented components resulted in statistically greater translational displacement over time compared with high-side reaming and use of a standard component. Further prospective clinical studies are needed to confirm these findings.

Clinical and radiographic outcomes of shoulder hemiarthroplasty for patients with glenoid medialization

BACKGROUND

Glenoid bone loss in shoulder arthroplasty is a difficult problem that is prone to complications because of challenges with achieving glenoid component fixation and stability. The purpose of this study was to evaluate the outcomes of primary shoulder hemiarthroplasty for patients with severe glenoid medialization precluding placement of a glenoid component.

METHODS

This was a retrospective case series evaluating patients who underwent shoulder hemiarthroplasty for severe glenoid erosion and medialization between 2010 and 2020. Patients were evaluated via chart review and phone survey to determine if there were any reoperations at final follow-up and to obtain Single Assessment Numeric Evaluation (SANE), American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), and Simple Shoulder Test (SST) scores. Preoperative and postoperative radiographs were evaluated and compared to determine glenoid morphology, version, medialization, acromiohumeral distance, and humeral offset. Final postoperative films were also evaluated for anterosuperior migration and signs of mechanical failure, including loosening or periprosthetic fracture.

RESULTS

Overall, there were 28 patients during this period who underwent shoulder hemiarthroplasty for severe glenoid medialization. Eight patients were deceased at the time of the study, 2 were unable to complete surveys because of dementia, and 7 were lost to follow-up. The final cohort included 11 shoulders and 11 patients with a mean age of 71 ± 7.1 years and mean follow-up of 6.7 years (range 1.6-13.0 years). Mean postoperative SANE, ASES, and SST scores were 80.6 ± 17.6, 71.5 ± 29.3, and 7.6 ± 2.0, respectively. There were no reoperations or revision surgeries at final follow-up. Radiographic evaluation demonstrated severe glenoid medialization and decreased lateral humeral offset, which was unchanged postoperatively. There were 2 patients with signs of anterosuperior migration at final radiographic follow-up but no signs of implant failure.

CONCLUSION

Shoulder hemiarthroplasty for severe medial glenoid bone loss provides modest clinical outcomes and low rates of reoperation at mid- to long-term follow-up and is an option worth considering in cases where placement of a glenoid component is challenging because of deficient bone stock and high risk for complications.

Outcomes of patients undergoing anatomical total shoulder arthroplasty with augmented glenoid components - a systematic review

Background

Glenoid loosening is an issue in anatomic total shoulder arthroplasty (a-TSA). This has been attributed to abnormal glenoid anatomy, common among these patients. Different alternatives have been proposed to tackle glenoid bone loss and restore joint alignment with augmented glenoid implants being increasingly used to deal with this problem. This systematic review aims to evaluate the clinical and radiological outcomes of patients undergoing augmented glenoid a-TSAs. Our hypothesis was that augmented glenoid components will lead to good patient outcomes with a low incidence of complications and revision procedures.

Methods

MEDLINE, EMBASE, CENTRAL and CINHAL were searched from inception to February 2022 for information pertaining to outcomes of patients undergoing a-TSA with augmented glenoid implants.

Results

Eighteen studies reported on outcomes of 814 a-TSA (800 participants) with a mean follow-up of 3.7 years. Most studies (67%) were Type IV level of evidence. Almost 70% of participants underwent an a-TSA secondary to primary glenohumeral osteoarthritis. Most glenoids were type B2 (73%). Augmented glenoids material was mostly all-polyethylene (81%) with full wedge (45%) and stepped components (38%) designs being the most common. Most studies reported good clinical outcomes. 17 patients (4%) underwent a revision surgery.

Conclusions

Our review found that patients undergoing a-TSA with augmented glenoid components report good outcomes at short-to-mid-term follow-up. Further research is warranted to determine if such outcomes remain similar in long term.

Level of evidence

Level III, Systematic Review of Therapeutic Studies.

Innovations in Shoulder Arthroplasty

Innovations currently available with anatomic total shoulder arthroplasty include shorter stem designs and augmented/inset/inlay glenoid components. Regarding reverse shoulder arthroplasty (RSA), metal augmentation, including custom augments, on both the glenoid and humeral side have expanded indications in cases of bone loss. In the setting of revision arthroplasty, humeral options include convertible stems and newer tools to improve humeral implant removal. New strategies for treatment and surgical techniques have been developed for recalcitrant shoulder instability, acromial fractures, and infections after RSA. Finally, computer planning, navigation, PSI, and augmented reality are imaging options now available that have redefined preoperative planning and indications as well intraoperative component placement. This review covers many of the innovations in the realm of shoulder arthroplasty.

Glenoid bone grafting in primary anatomic total shoulder arthroplasty: a systematic review

BACKGROUND

Primary anatomic total shoulder arthroplasty can be challenging in patients with complex glenoid wear patterns and bone loss. Severe retroversion (>15°) or significant bone loss may require bone grafting. This review summarizes the rate of revision and long-term outcomes of anatomic total shoulder arthroplasty with bone graft.

METHODS

A systematic search of MEDLINE, Embase, PubMed, and CENTRAL databases was conducted from the date of inception to 23 October 2018. Two reviewers independently screened articles for eligibility and extracted data for analysis. The primary outcome was rate of revision. The secondary outcomes were rate of component loosening, functional outcome, and range of motion.

RESULTS

Of the 1056 articles identified in the search, 26 underwent full-text screening and 7 articles were included in the analysis. All procedures were one-stage anatomic total shoulder arthroplasties. The rate of revision was 5.4% with component loosening and infection listed as indications over a weighted mean follow-up period of 6.3 years. Complications occurred in 12.6% of patients.

CONCLUSION

Glenoid bone grafting in anatomic total shoulder arthroplasty results in comparable revision rates and improvement in pain compared to augmented glenoid components and reverse shoulder arthroplasty. Due to the low quality of evidence, further prospective studies should be conducted.

LEVEL OF EVIDENCE

IV.

Anatomical shoulder arthroplasty in epileptic patients with instability arthropathy and persistent seizures

PURPOSE

Epileptic seizures can cause shoulder dislocation, recurrent instability and eventually arthritis. The purpose of this study was to report the results, complications and rate of revision surgery following anatomical shoulder arthroplasty in epileptic patients with instability arthropathy.

METHODS

A consecutive series of eight patients with epilepsy underwent anatomical shoulder arthroplasty for recurrent shoulder instability and were retrospectively reviewed after a mean of 4.7 years (range, 2-7.5 years). These included three total shoulder replacements and five humeral resurfacing hemiarthroplasty procedures.

RESULTS

Mean age of the cohort was 33 years (range, 17-44). All patients experienced post-operative grand mal seizures. Two patients with hemiarthroplasty required further surgery due to painful glenoid erosion. No residual cases of instability were noted. Mean active forward elevation and external rotation improved following surgery. The Oxford Shoulder Score improved from 15 pre-operatively (range, 7-22) to 26 post-operatively (range, 12-45) ( p = 0.031). This was accompanied by an increase in the mean Subjective Shoulder Value, which improved from 29 (range, 10-80) pre-operatively to 53 (range, 15-90) post-operatively ( p=0.042).

CONCLUSIONS

Anatomical shoulder arthroplasty may offer a solution for the treatment of instability arthropathy in patients with epilepsy and persistent seizures.