Total shoulder arthroplasty using an inlay mini-glenoid component for glenoid deficiency: a 2-year follow-up of 9 shoulders in 7 patients

Anatomic glenohumeral arthroplasty: State of the art

Anatomical total shoulder arthroplasty in its modern form where it reproduces the normal shoulder has been utilized clinically for more than half a century. As the technology and the designs have changed to recreate the humeral and glenoid sides of the joint, the sophistication of design has resulted in the growing number of cases annually worldwide. This increase is due in part to the increasing number of indications that the prosthesis can treat with successful results. On the humeral side, there have been design changes to better reflect the proximal humeral anatomy, and humeral stems are increasingly placed safely without cement. Platform systems which allow conversion of a failed arthroplasty to a reverse configuration without stem extraction is another design change. Similarly, there has been increasing utilization of short stem and stemless humeral components. Extensive experience with shorter stem and stemless devices, however, has yet to demonstrate the purported advantages of these devices, as recent studies have demonstrated equivalent blood loss, fracture rates, operative times, and outcome scores. Easier revision with these shorter stems remains to be definitively established, with only one study comparing the ease of revision between stem types. On the glenoid side, hybrid cementless glenoids, inlay glenoids, cementless all-polyethylene glenoids, and augmented glenoids have all been investigated; however, the indications for these devices remain unclear. Lastly, innovative surgical approaches to implanting shoulder arthroplasty and the use of patient specific guides and computerized planning, while interesting concepts, still await validation before they are utilized on a widespread basis. While reverse shoulder arthroplasty has been increasingly used to reconstruct the arthritic shoulder, anatomic glenohumeral replacement maintains a significant role in the armamentarium of the shoulder surgeon.

Clinical and radiographic outcomes following anatomic total shoulder arthroplasty utilizing an inset glenoid component at 2-year minimum follow-up: a dual center study

BACKGROUND

Anatomic total shoulder arthroplasty (aTSA) is a successful and reproducible treatment for patients with painful glenohumeral arthritis. However, long-term outcomes using traditional onlay glenoid components have been tempered by glenoid loosening. Inset components have been proposed to minimize glenoid loosening by reducing edge-loading and opposite-edge lift-off forces with humeral translation. Successful short- and long-term outcomes have been reported while using inset glenoid implants. The current study is the largest study presenting a minimum of 2-year follow-up data following aTSA with an all-polyethylene inset glenoid component (Shoulder Innovations, Holland, MI, USA).

METHODS

A dual center, retrospective review of patients undergoing aTSA using an Inset glenoid component by 2 fellowship-trained shoulder surgeons at 2 separate institutions from August, 2016, to August, 2019, was performed. Minimum follow-up was 2 years. Range of motion (ROM), visual analog scale (VAS) pain scores, Single Assessment Numeric Evaluation (SANE), and American Shoulder and Elbow Surgeons (ASES) scores were obtained. Radiographic outcomes, including central peg lucency and glenoid loosening, were assessed by 3 independent reviewers on the postoperative Grashey and axillary radiographs obtained at the final follow-up.

RESULTS

Seventy-five shoulders were included for the final analysis. The mean age of the entire cohort was 64 (±11.4) years. Twenty-one (28%) glenoids were type A1, 10 (13.3%) were type A2, 13 (17.3%) were type B1, 22 (29.3%) were type B2, 6 (8%) were type B3, and 3 (4%) were type D. At a minimum follow-up of 24 months (mean: 28.7 months), a significant improvement in ROM in all planes was observed. Significant improvements in VAS (5.1-0.9, P < .001), SANE (39.5-91.2, P < .001), and ASES (43.7-86.6, P < .001) scores were observed. There were 4 (5.3%) cases of central peg lucency about the inset glenoid component and one (1.3%) case of glenoid loosening. No revisions were performed for glenoid loosening.

CONCLUSION

At a minimum of 2 years postoperatively, there were significant improvements in ROM, VAS, SANE, and ASES scores with very low rates of central peg lucency and glenoid loosening in patients undergoing aTSA with an inset glenoid component. Further work is needed to determine the long-term benefit of this novel implant.

Glenoid Prosthesis Design Considerations in Anatomic Total Shoulder Arthroplasty

Total shoulder arthroplasty is an increasingly popular option for the treatment of glenohumeral arthritis. Historically, the effectiveness of the procedure has largely been determined by the long-term stability of the glenoid component. Glenoid component loosening can lead to clinically concerning complications including pain with movement, loss of function, and accumulation of debris which may require surgery to revise. In response, there has been a push to optimize the design of the glenoid prosthesis. Traditional contemporary glenoid components use pegs for fixation and are made entirely of polyethylene. Variations on the standard implant include keeled, metal-backed, hybrid, augmented, and inlay designs. There is a wealth of biomechanical and clinical studies that report on the effectiveness of these different designs. The purpose of this review is to summarize existing literature regarding glenoid component design and identify key areas for future research. Knowledge of the rationale underlying glenoid design will help surgeons select the best component for their patients and optimize outcomes following TSA.

Total shoulder arthroplasty using an inlay glenoid component for glenoid deficiency: mid- to long-term follow-up of a previously published cohort

BACKGROUND

The short-term results of total shoulder arthroplasty with an inlay glenoid component performed by a single surgeon in patients with glenoid bone loss have previously been reported. The purpose of this study was to investigate the mid- to long-term clinical and radiographic outcomes of these patients.

METHODS

We identified a cohort of patients who underwent total shoulder arthroplasty with an inlay glenoid component performed by a single surgeon between 2010 and 2019 for severe glenoid dysplasia and/or glenoid bone loss. Patients with a minimum of 2 years' follow-up were evaluated regarding preoperative and postoperative range of motion, radiographic findings, visual analog scale pain scores, and Single Assessment Numeric Evaluation scores.

RESULTS

Overall, 39 shoulders in 33 patients were treated with an inlay glenoid component for severe glenoid bone loss. Four patients were lost to follow-up, and 1 patient died with a well-functioning implant in place. The final cohort included 34 shoulders in 28 patients (46.4% female patients [13 of 28] and 53.6% male patients [15 of 28]) with a mean age of 66.9 years (range, 58-81 years) and mean follow-up period of 68.3 months. Of the 34 cases, 5 were revision cases. One patient died following 2-year follow-up. Of the shoulders, 10 were classified as Walch type A2, 4 were classified as Walch type B3, and 15 were classified as Walch type C; 5 shoulders were unable to be classified. We observed statistically significant increases in range of motion (forward elevation, 38.1° [P < .001]; external rotation, 18.8° [P < .001]) and improvement in the Single Assessment Numeric Evaluation score (from 26.6 to 81.0, P < .001). Two patients underwent conversion to reverse shoulder arthroplasty at 2.2 and 1.7 years postoperatively.

CONCLUSION

Inlay glenoid components provide a low rate of revision and improved clinical and functional outcomes at mid- to long-term follow-up.

Inlay total shoulder arthroplasty for primary glenohumeral arthritis

Background

Anatomic total shoulder arthroplasty with a nonspherical humeral head and inlay glenoid replacement has been introduced in the past; however, clinical evidence remains limited. We hypothesized that patients with advanced glenohumeral arthritis demonstrate significant improvements in pain and function.

Methods

Prospective patient-reported outcomes (PROs) included the American Shoulder and Elbow Surgeons score, a pain visual analog scale, and satisfaction. Range of motion was compared to the preoperative status. A sensitivity analysis examined responder rates and compared them to literature thresholds using the minimal clinically important difference and substantial clinical benefit. The preoperative glenoid morphology was determined using the Walsh classification. Zone-specific periprosthetic radiolucent lines were quantified at the last follow-up.

Results

Thirty-nine shoulders in 36 patients (3 bilateral) with a mean age of 65.9 years (26 males, 13 females) and a mean follow-up of 41.0 months were included. Ninety-three percent had grade III osteoarthritis, and 7% grade II. The glenoid Walsh classification included A1 (25%), A2 (25%), B1 (22%), B2 (25%), and C (3%). All PROs improved significantly (P < .001) with a mean American Shoulder and Elbow Surgeons score from 30.4 to 77.1, a pain visual analog scale from 8.1 to 1.5, and excellent (9.1/10) patient satisfaction. PRO-related responder rates for minimal clinically important difference and substantial clinical benefit were ≥85%. Forward elevation improved from 107° to 155°, and external rotation from 22° to 51°. One intraoperative glenoid rim fracture led to advanced radiolucency; no other clinically relevant lucency was observed.

Conclusion

Treatment with inlay total shoulder arthroplasty demonstrated significant functional improvement, excellent pain relief, and patient satisfaction in patients with advanced shoulder arthritis and various glenoid morphology types. Our initial results provide further support for this new option in primary shoulder replacement.

Discoid Labral Meniscus Covering Two-Thirds of a Type C Glenoid: A Case Report

Background

Glenoid morphology and dysplasia have been extensively described in conjunction with shoulder arthritis. Dysplastic glenoids have a substantial inherent retroversion, a deficient posteroinferior rim, a short scapular neck, and an inferior inclination of the joint surface. The effect of dysplasia on fracture surgery has not been reported to the same extent.

Case presentation

A 65‐year‐old man presented with a proximal humeral fracture. The patient was scheduled for osteosynthesis. The head was deemed unrepairable at the time of surgery and the operative plan changed to replace the proximal humerus. A discoid meniscus‐like labral extension covering two‐thirds of the glenoid was encountered. This finding covered a dysplastic glenoid. The combination of a fracture and a dysplastic glenoid had not been accounted for and made the reconstruction more difficult. The patient received a reverse total shoulder arthroplasty after perioperative considerations regarding reconstruction. At the 2‐month follow up, the patient had a satisfactory clinical outcome, with 90° of flexion and minimal residual pain.

Conclusion

This case illustrates that elective disorders with dysplasia also present to the fracture team. Careful analysis of preoperative imaging should result in an operative plan taking unexpected findings into account.

Medium to long-term results of a recessed glenoid for glenoid resurfacing in total shoulder arthroplasty

BACKGROUND

Recessed mini-glenoid components provide an alternative to total shoulder replacement that may avoid some of the known shortcomings and complications associated with shoulder hemiarthroplasty or standard glenoid components in difficult cases. This study reports survivorship, radiological and clinical outcomes of a recessed mini-glenoid implant in a consecutive cohort.

METHODS

Retrospective cohort study reporting outcomes of 28 consecutive shoulders (27 patients) following total shoulder replacement using a recessed, cemented mini-glenoid implant at two sites.

RESULTS

The most frequent diagnosis was primary osteoarthritis (79%); glenoid morphology was Walch Type A (67%), B1 15%, B2 10% and C 10%. At final follow-up, pain was 16.3 (SD = 23.1), American Shoulder and Elbow Score was 64.5 (SD = 31.9) and (normalized) Constant score was 83.0 (SD = 20.7). Implant survivorship at average final follow-up of seven years (3-13) was 96.4%. Seven mini-glenoids showed small peripheral radiolucent lines at one-year X-ray follow-up but were non-progressive on subsequent imaging.

DISCUSSION

Recessed polyethylene mini-glenoid is an attractive alternative for shoulder arthroplasty and provides an intermediate solution between standard glenoid components and hemiarthroplasty. Our medium to long-term results demonstrate reliable clinical outcomes, absence of glenoid erosion, low complication rate and satisfactory implant survivorship.

Anatomic total shoulder arthroplasty with an inlay glenoid component: clinical outcomes and return to activity

BACKGROUND

Biomechanical studies show that inlay glenoid components in total shoulder arthroplasty (TSA) can reduce edge loading and opposite-edge lift-off forces with humeral translation compared with onlay glenoids. However, clinical data for these implants are lacking. We report clinical outcomes and return to activities after anatomic TSA with an inlay glenoid component and a stemless ovoid humeral head in an active, young patient population.

METHODS

A retrospective review of TSA with an inlay glenoid component and an ovoid humeral head component was performed for 27 shoulders. Patients were evaluated with patient-reported outcome measures, range of motion, and radiographs. Return to occupational and sporting activity, complications, and reoperations were analyzed.

RESULTS

A total of 27 shoulders were available for minimum 2-year follow-up. Age averaged 52.1 years, and 92.6% of shoulders were in male patients. The preoperative Walch grade was A1 or A2 in 15 shoulders (55%), B1 in 8 (30%), and B2 in 4 (15%). Patients showed significant improvements in patient-reported outcome measures, active forward flexion, and external rotation (P < .001) with no reoperations. At an average of 3.7 months, the rate of return to work was 92.6%, with 76.0% of those patients returning to their preoperative occupational demand level. At an average of 9.1 months, 75% of patients who responded to our custom survey returned to sport, with 50% achieving the same level or a higher level of sporting activity. Annual postoperative radiographs revealed no inlay component loosening.

CONCLUSION

Anatomic TSA with an inlay glenoid coupled with a stemless ovoid humeral head in an active population resulted in improved clinical outcomes, no reoperations or radiographic loosening, and a high rate of return to activity at shorter-term follow-up.

Long-term follow-up of total shoulder replacement surgery with inset glenoid implants for arthritis with deficient bone

BACKGROUND

Total shoulder replacement surgery has been a successful treatment for patients with shoulder arthritis. However, long-term results are limited by complications such as glenoid loosening, wear, and instability. Also, glenoid bone deficiency limits available treatment options and outcomes. Successful short-term outcomes have been reported previously using inset glenoid implants for deficient arthritic bone, but long-term outcomes have not been reported using this technique.

METHODS

A retrospective analysis was performed on 21 of 24 consecutive patients treated with inset glenoid implants for severe glenohumeral joint arthritis with bone deficiency with prospectively collected data. Inclusion criteria were patients with shoulder arthritis and severe glenoid bone deficiency, defined by perpendicular glenoid vault depth less than 15 mm. No bone grafts were used. All patients were evaluated preoperatively and after surgery with physical examination, radiographic studies, and outcome measures. There were 10 males and 11 females, 17 cases with osteoarthritis and 4 with inflammatory arthritis, and 5 patients with rotator cuff tears (3 full thickness and 2 partial tears). Mean age was 68 years.

RESULTS

There were no surgical complications. At a mean follow-up of 8.7 years, there were statistically significant improvements (P < .001) in visual analog pain scores (7.7 to 0.1), American Shoulder and Elbow Surgeons outcome scores (23 to 95), and range of motion. There were no loose glenoids. No patients required any revision surgery.

CONCLUSIONS

This study documents the long-term efficacy and safety of total shoulder replacement surgery with inset glenoid implants used to reconstruct deficient, arthritic glenoid bone.

Journey of the glenoid in anatomic total shoulder replacement

Anatomic total shoulder arthroplasty (TSR) has been shown to generate good to excellent results for patients with osteoarthritis and a functioning rotator cuff. Many studies have reported that the glenoid component loosening and failure remain the most common long-term complication of total shoulder arthroplasty. The approach to glenoid component is critical because a surgeon should consider patient-specific anatomy, preserving bone stock and joint line restoration, for a good and durable shoulder function. Over the years, different glenoid design and materials have been tried in various configurations. These include cemented polyethylene, uncemented metal-backed and hybrid implants. Although advances in biomechanics, design and tribology have improved our understanding of the glenoid, the journey of the glenoid component in anatomic total shoulder arthroplasty has not yet reached its final destination. This article attempts to describe the evolution of the glenoid component in anatomic TSR and current practice.

Characterization of the dysplastic Walch type C glenoid

Aims

The Walch Type C dysplastic glenoid is characterized by excessive retroversion. This anatomical study describes its morphology.

Patients and Methods

A total of 29 shoulders with a dysplastic glenoid were analyzed. CT was used to measure retroversion, inclination, height, width, radius-of-curvature, surface area, depth, subluxation of the humeral head and the Goutallier classification of fatty infiltration. The severity of dysplasia and deficiency of the posterior rim of the glenoid were recorded.

Results

A type C glenoid occurred in 1.8% of shoulders referred to our tertiary centres. The mean retroversion, inclination, height, width, radius-of-curvature, surface area, and depth of the glenoid were 37°, 3°, 46 mm, 30 mm, 37°, 1284 mm3, and 16 mm, respectively. The mean posterior subluxation was 90%. The Goutallier class was < 2 in 25 shoulders (86%). Glenoid dysplasia was mild in four, moderate in 14, and severe in 11 shoulders. The typical appearance of the posterior glenoid rim had a rounded or ‘lazy J’ morphology. The glenoid neck was deficient in 18 shoulders (62%).

Conclusion

A dysplastic Type C glenoid characteristically has a uniconcave retroverted morphology, a deficient posteroinferior rim and scapular neck, and a reduced depth. These findings help to define the unique anatomical variations and may aid the planning of surgery and the development of components for these patients. Cite this article: Bone Joint J 2018;100-B:1074–9.