Clinical results and survivorship of the Mathys Affinis Short, Short Stem Total Shoulder Prosthesis

Proximal humeral bone loss in stemless shoulder arthroplasty: potential factors influencing bone loss and a new classification system

INTRODUCTION

Proximal humeral bone loss in total shoulder arthroplasty (TSA) is more frequent than in hemiarthroplasty. Factors such as age, gender, inclination angle, and radiolucent lines may also contribute. Additionally, current bone loss grading systems are often not sensitive enough to detect slight bone changes, especially at the medial calcar where bone loss is commonly observed. This study uses a new, more detailed bone loss grading system to evaluate factors that could influence bone loss at the proximal humerus.

MATERIALS AND METHODS

In this single-center prospective study, patients underwent hemiarthroplasty or TSA with an anatomic stemless prosthesis. Bone loss was measured at the proximal humerus using the new grading system. The effect of treatment type, age, gender, radiolucent lines, and inclination angle on bone loss was evaluated. The Constant-Murley score of patients was assessed and complications recorded.

RESULTS

Ninety-one shoulders were available for the final follow-up examination at a median of 85.0 months (range 82.6-121.1 months). Bone loss was found at the proximal humerus in approximately one-third of shoulders, and significantly more shoulders had bone loss in TSA than in hemiarthroplasty (P = 0.03). However, this difference was no longer significant after stratifying by gender and age (P > 0.05). Bone loss significantly correlated with gender (P = 0.03) but not with treatment type, radiolucent lines, and the postoperative inclination angle (P > 0.05). Most Constant-Murley score components did not differ significantly between shoulders with and without bone loss (P > 0.05). Lastly, six complications and four revisions were reported.

CONCLUSIONS

Results showed gender had the greatest influence on bone loss after stemless shoulder arthroplasty. Furthermore, both patients with or without bone loss can expect similar clinical outcomes with the stemless prosthesis used in this study. Lastly, the new grading system is simple and straightforward to use.

Mid-term results of Eclipse total shoulder arthroplasty

AIMS

The use and variety of stemless humeral components in anatomical total shoulder arthroplasty (TSA) have proliferated since their advent in 2004. Early outcomes are reassuring but independent mid-term results are scarce. This independent study reports a consecutive series of 143 Eclipse stemless shoulder prostheses with a minimum five-year (5 to 10) follow-up.

METHODS

Outcomes of 143 procedures undertaken for all indications in 131 patients were reviewed, with subset analysis of those for osteoarthritis (OA) (n = 99). The primary outcome was the Oxford Shoulder Score (OSS) at a minimum of five years. Secondary outcomes were ranges of motion and radiological analysis of humeral radiolucency, rotator cuff failure, and glenoid loosening.

RESULTS

Mean OSS at mean follow-up of 6.67 years (5.0 to 10.74) was 40.12 (9 to 48), with no statistically significant difference between those implanted for a non-OA indication and those for OA (p = 0.056) or time-dependent deterioration between two years and five years (p = 0.206). Ranges of motion significantly improved compared with preoperative findings and were maintained between two and five years with a mean external rotation of 38° (SD 18.1, 0 to 100) and forward elevation of 152° (SD 29.9, 90 to 180). Of those components with radiographs suitable for analysis (n = 83), 23 (28%) were found to have a least one humeral radiolucent line, which were predominantly incomplete, less than 2 mm, and in a single anatomical zone. No humeral components were loose. A radiolucent line was present around 22 (15%) of glenoid components, and 15 (10%) of components had failed. Rotator cuff failure was found in 21 (15%) components. The mean time to either glenoid or rotator cuff failure was greater than three years following implantation. Survivorship was 96.4% (95% CI 91.6 to 98.5, number at risk 128) at five years, and 94.3% (95% CI 88.2 to 97.3, number at risk 76) at seven years, both of which compare favourably with best results taken from available registries.

CONCLUSION

Functional and radiological outcomes of the Eclipse stemless TSA are excellent, with no loose humeral components at minimum five-year follow-up. The presence of radiolucent lines is of interest and requires long-term observation but does not impact on the clinical results. Of the eight revisions required, this was predominantly for glenoid and rotator cuff failure. Cite this article: Bone Joint J 2022;104-B(1):83-90.

Early fixation of the humeral component in stemless total shoulder arthroplasty : a radiostereometric and clinical study with 24-month follow-up

AIMS

Stemless humeral implants have been developed to overcome stem-related complications in total shoulder arthroplasty (TSA). However, stemless implant designs may hypothetically result in less stable initial fixation, potentially affecting long-term survival. The aim of this study is to investigate early fixation and migration patterns of the stemless humeral component of the Simpliciti Shoulder System and to evaluate clinical outcomes.

METHODS

In this prospective cohort study, radiostereometric analysis (RSA) radiographs were obtained in 24 patients at one day, six weeks, six months, one year, and two years postoperatively. Migration was calculated using model-based RSA. Clinical outcomes were evaluated using the visual analogue scale (VAS), the Oxford Shoulder Score (OSS), the Constant-Murley Score (CMS), and the Disabilities of the Arm, Shoulder and Hand (DASH) score.

RESULTS

At two years, median translation along the x-, y-, and z-axis was -0.12 mm (interquartile range (IQR) -0.18 to 0.02), -0.17 mm (IQR -0.27 to -0.09), and 0.09 mm (IQR 0.02 to 0.31). Median rotation around the x-, y-, and z-axis was 0.12° (IQR -0.50 to 0.57), -0.98° (IQR -1.83 to 1.23), and 0.09° (IQR -0.76 to 0.30). Overall, 20 prostheses stabilized within 12 months postoperatively. Four prostheses showed continuous migration between 12 and 24 months. At two-year follow-up, with the exception of one revised prosthesis, all clinical scores improved significantly (median VAS difference at rest: -3.0 (IQR -1.5 to -6.0); OSS 22.0 (IQR 15.0 to 25.0); CMS 29.5 (IQR 15.0 to 35.75); and DASH -30.0 (IQR -20.6 to -41.67) (all p < 0.001)) with the exception of one revised prosthesis.

CONCLUSION

In conclusion, we found that 20 out of 24 implants stabilized within 12 months postoperatively. The significance of continuous migration in four implants is unclear and future research on the predictive value of early migration for future loosening in TSA is required. Clinical results revealed a clinically relevant improvement. Cite this article: Bone Joint J 2022;104-B(1):76-82.