Midterm clinical outcome of uncemented short-stem reversed shoulder arthroplasty

Radiological and Clinical Outcome Differences Between Standard and Short Stem in Reverse Total Shoulder Arthroplasty: A Systematic Review

BACKGROUND

In recent years, the use of short cementless humeral components in reverse total shoulder arthroplasty (RTSA) has increased. This systematic review aimed to compare the radiological and clinical outcomes of uncemented RTSA using short versus standard humeral stems and assess the impact of these radiological changes on clinical outcomes.

METHODS

A systematic electronic search was performed by two independent reviewers using PubMed, Scopus, and Cochrane Library databases on 10 December 2024. Inclusion criteria involved studies that assessed the radiological and clinical outcomes and overall complication rates of cementless RTSA with short or standard stems in patients with osteoarthritis, cuff tear arthropathy, post-traumatic, and rheumatoid arthritis with a follow-up of at least 1 year. The following data were extracted: radiological parameters of stems including implant subsidence, humeral loosening, and humeral osteolysis and clinical outcomes as Visual Analog Scale pain, American Shoulder and Elbow Surgeons score, Constant Score and Single Assessment Numeric Evaluation score.

RESULTS

A total of 13 studies including 1485 shoulders in 1460 patients were analyzed with a median age at surgery of 74.5 years. The short stem group recorded worse radiological outcomes examined such as humeral loosening, lucencies around the implants, and osteolysis. No significant differences were observed in the clinical outcomes and overall complications between the two types of stems.

CONCLUSIONS

Both short and standard stems are valid options in cementless RTSA. Minimal differences in radiological outcomes were found in favor of RTSA implanted with short stems, while postoperative clinical outcomes were similar between the two types of implants.

Assessing the efficacy: mid-term clinical and radiological outcomes of the comprehensive short stem system in reverse shoulder arthroplasty

BACKGROUND

For degenerative shoulder disease, reverse shoulder arthroplasty (RSA) has proven successful; however, problems such as scapular notching and instability still exist. These difficulties are intended to be addressed by recently improved prosthesis designs with reduced neck-shaft angles (NSA). Still, there are issues with complications, particularly with the humerus. In an effort to avoid these problems and maintain bone stock, a recently designed straight-short-stem humeral component was used; however, yet its clinical and radiological outcomes in RSA remain largely unexplored.

MATERIAL AND METHODS

Using a 55 mm straight short stem (Comprehensive Reverse Shoulder System; Zimmer Biomet), a retrospective analysis of 93 patients undergoing primary RSA was carried out. Clinical assessments, including scores and range of motion, were conducted both before and after surgery. Complications, bone adaptation, and stem alignment were all evaluated radiographically. Significant correlations between postoperative shoulder movements and function were linked with angles of prosthesis lateralization and distalization.

RESULTS

Patients demonstrated significant improvements in clinical scores at 35-month follow-up on average: Constant-Murley (76.4 ± 13.4), American Shoulder and Elbow Surgeons (84.8 ± 16.5), Disabilities of Arm, Shoulder, the Hand (17.1 ± 15.8), and University of California and Los Angeles (7.1 ± 1.5). Radiographic assessments showed no stem loosening and stable implant attachment. There was no scapular notching, and there were noticeable improvements in shoulder range of motion and function.

DISCUSSION AND CONCLUSION

This study validates the efficacy of a straight short stem for acceptable clinical outcomes and implant stability in RSA. Notably, it demonstrates specific angle ranges crucial for optimal postsurgical shoulder function. The findings suggest this stem design presents potential benefits in RSA, highlighting its safety and effectiveness while providing insights for future clinical strategies. The study contributes valuable data toward understanding and enhancing patient outcomes in shoulder arthroplasty procedures.

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.

Does the proximal humeral bone quality influence alignment after reverse total shoulder arthroplasty with short humeral stems?

PURPOSE

When compared to standard-length humeral stem in reverse total shoulder arthroplasty (RTSA), short humeral stems in RTSA require good proximal humeral metaphyseal bone quality to gain proper and secure fixation during prosthetic implantation. Shorter humeral stems potentially carry more risk of misalignment than standard or long humeral stems. The hypothesis was that misalignment of the short humeral stems is influenced by regional bone quality.

METHODS

RTSA with a short curved humeral stem with neck-shaft angle (NSA) default of 132.5° was reviewed. The study group included 35 cases at a mean age of 75.97 (± 6.23) years. Deltoid-tuberosity index (DTI) was measured to evaluate proximal humeral bone quality. The deltoid tuberosity index was measured at immediately above position of the upper end of the deltoid tuberosity. Stem alignment was given by the angle measured in degrees between the intramedullary humeral shaft axis and the axis of the humeral implant stem.

RESULTS

The patient's mean DTI was 1.37 ± 0.16 (median, 1.32; range, 1.12-1.80). 22 patients had poor bone quality (DTI < 1.4), compared to 13 patients with acceptable bone quality (DTI > 1.4). After RTSA, ten humeral components (29%) were neutrally aligned, whereas 25 humeral components (71%) were misaligned. There was no correlation between misalignment and DTI (r = 0.117; p = 0.504). But there was a strong correlation between misalignment and the patient's own NSA (r = - 0.47; p = 0.004). The postoperative stem position and stem misalignment are not associated with functional outcomes (p > 0.05).

CONCLUSION

The misalignment of the short curved humeral stem frequently occurs. Poor reginal humeral bone quality does not influence misalignment after RTSA with a short humeral stem. Postoperative stem alignment is associated with the patient's preoperative NSA and method of neck cut. The misalignment does not affect functional outcomes for midterm follow-up. Further long-term follow-up studies are needed to confirm its clinical relevance.