Clinical and radiographic outcomes of cementless reverse total shoulder arthroplasty for proximal humeral fractures

Stress shielding: short-term radiological results of the reverse shoulder arthroplasty with an anatomic proximal coated stem in proximal humeral fractures

PURPOSE

This study aims to determine the stress shielding and other radiological outcomes of patients who underwent an uncemented reverse shoulder arthroplasty (RSA) with an anatomic proximal coated stem for complex proximal humeral fractures (PHF) with 3 or 4 parts at 2 years postoperatively.

METHODS

37 shoulders underwent an uncemented RSA for PHF from November 2015 to February 2019 and were followed up for 2 years. A radiographic assessment of stress shielding, filling ratio, stem stability (radiolucent lines/subsidence/alignment), tuberosity healing and notch was performed.

RESULTS

The mean age at the time of surgery was 72 years (range, 61-85). Stress shielding was appreciated in 31 shoulders (83.8%). The most important characteristic of stress shielding is cortical resorption: Grade 3 resorption occurred in 3 shoulders (8.1%) and grade 4 in 23 (62.2%) as per the grading system defined by Inoue et al. (Inoue et al. in J Shoulder Elbow Surg 26:1984-1989, 2017). A high occurrence of bone resorption was observed in Gruen zones 2 (Lateral Stress shielding) and 7 (Medial Stress shielding). The mean distal filling ratio in patients without stress shielding was 78,48(SD 14,9), whereas in patients with stress shielding, it was slightly higher with a mean of 81,68% (SD 4,89). Tuberosity healing was found in 94.6% (35/37) of the shoulders. No patient had any radiolucent line. No notch was observed.

CONCLUSION

At short-term follow-up, a high rate of tuberosity healing was achieved (94.6%) even though stress shielding was found in 83.8% (31/37) of the shoulders. Bone resorption was most frequently observed externally at zone 2 (Lateral stress shielding) and internally at zone 7 (Medial stress shielding). A higher filling ratio was associated with an increased occurrence of stress shielding. The uncemented anatomic humeral component did not result in early loosening.

LEVEL OF EVIDENCE

IV; Case Series; Treatment study.

Cementless reverse total shoulder arthroplasty implantation with humeral matchstick autograft augmentation: early radiographic outcomes

BACKGROUND

Humeral-sided complications account for up to 21% of all revision reverse total shoulder arthroplasty (RTSA) surgeries. Stress shielding with large bulky stems can lead to proximal bone resorption per Wolff law, complicating further surgeries. Previously published studies suggest that lowering the metaphyseal implant fill ratio can lead to fewer adaptive radiographic changes and decreased bone resorption. Inspired by these studies, cementless primary RTSA implantation technique with humeral matchstick autografts was proposed to augment cementless humeral constructs, foster the use of a smaller size stem, and create primary stability of the humeral implant even in osteoporotic or in-between size medullary canals. In this study, retrospective review of this cementless RTSA technique with short-term radiographic evaluation was performed.

METHODS

Forty-six nonconsecutive patients underwent primary RTSA with a short-stem cementless prosthesis (Stryker Ascend Flex) augmented by matchstick bone grafting from January to July 2020. Patient demographics were recorded, and follow-up radiographs were retrospectively reviewed to assess metaphyseal fill ratios and incidence of stress shielding at minimum 1-year follow-up. Discrepancies between templated and final stem sizes were recorded, along with all intraoperative and postoperative complications.

RESULTS

Of the 46 patients originally identified, there were 5 men and 41 women with a mean age of 71 years (standard deviation [SD] 7, range 53-88). Mean templated stem size was 4 (SD 2, range 1-8), whereas the mean final implant size was 2 (SD 1, range 1-3). Mean fill ratios were 0.76 (SD 0.06, range 0.54-0.89) along the metaphysis and 0.67 (SD 0.09, range 0.49-0.83) along the diaphysis. There were no intraoperative humeral fractures from implantation. All patients were available for radiographic follow-up with a mean of 19 months (SD 8, range 12-40). There were 3 cases (7%) of proximal humeral stress shielding, with average fill ratios of 0.857 and 0.807 in the metaphysis and diaphysis, respectively. There were 3 patients (7%) who underwent revision surgeries for baseplate failure and periprosthetic humeral fracture. There were no cases of early humeral loosening.

DISCUSSION

Matchstick autograft humeral augmentation is a simple, promising surgical technique with low intraoperative complication rates and good short-term radiographic outcomes. When the implant fill ratio is successfully reduced, there is a possible lower risk of humeral stress shielding. The authors believe this technique can help maximize implant stability in cementless shoulder arthroplasty and preserve humeral bone stock for future revision surgeries.

Arthroplasty as Primary Treatment for Metadiaphyseal Proximal Humerus Fractures: A Viable Alternative to Osteosynthesis for the Elderly

Introduction

in the elderly patient population, where fracture comminution, osteoporotic fractures, and associated arthritis or rotator cuff pathologies dominate, metadiaphyseal proximal humeral fracture is a challenging subset of fractures to treat. This study reports on cementless long-stem reverse total shoulder arthroplasty (RTSA) as primary treatment of metadiaphyseal proximal humeral fractures in elderly patients.

Materials & Methods

Between January 2018 and October 2021, 22 consecutive patients sustained proximal humerus fractures with metadiaphyseal extension and underwent surgery with cementless long-stem RTSA. Patients older than 60 years with minimum 1 year of clinical and radiographic follow-up were included. Patient demographics, range of motion, and patient reported outcomes [Visual Analog Scale (VAS) pain scale, Simple Shoulder Test (SST), Subjective Shoulder Value (SSV), and American Shoulder Elbow Surgeon (ASES) scores] were retrospectively collected. Postoperative X-rays were evaluated for fracture and tuberosity union.

Results

There were 14 eligible patients with a median age of 71 years (range 61-91 years) and a median 13 months follow-up. At final follow-up, the median active elevation was 120° (range 80°-150°), external rotation was 40° (range 0°-50°), and internal rotation was 40° (range 0°-80°). Median VAS was 2 (range 0-8), SST was 71% (range 33%-92%), SSV was 78% (range 20-90%), and ASES was 73 (range 17-90). All patients exhibited radiographic union. There were five minor complications in three patients: postoperative neuropathy, tuberosity nonunion, scapula notching, and proximal humeral stress shielding.

Conclusion

Cementless long-stem RTSA is a viable alternative to primary fracture fixation in the elderly patient population with metadiaphyseal proximal humerus fractures.

Reverse Total Shoulder Arthroplasty with a Cementless and Metaphyseal Stem Fixation Is a Viable Option for the Treatment of Proximal Humeral Fractures with Calcar Involvement

BACKGROUND

The purpose of the study was to evaluate the suitability of reverse total shoulder arthroplasty (RTSA) with a cementless and metaphyseal stem fixation as a treatment for complex proximal humeral fractures (PHFs) with a calcar fragment when this may be fixed with a steel wire cerclage. Clinical and radiographic outcomes were compared with the same RTSA for PHFs without a calcar fragment at a minimum of five-year follow-up.

METHODS

A retrospective analysis was performed on acute PHFs "with a medial calcar fragment" (group A) and "without a calcar fragment" (group B) treated with a RTSA and cementless metaphyseal stem fixation.

RESULTS

At an average follow-up of 6.7 years (5-7.8 years), no statistical difference was observed comparing group A (18 patients) to group B (50 patients) for active anterior elevation (141 ± 15° vs. 145 ± 10°, p = 0.67), active external rotation ER1 (49 ± 15° vs. 53 ± 13°, p = 0.55), and active internal rotation (5 ± 2 vs. 6 ± 2, p = 0.97). Similarly, a comparison of ASES score (89.2 ± 10 vs. 91.6 ± 9, p = 0.23) and Simple Shoulder Test score (91.1 ± 11 vs. 90.4 ± 10, p = 0.49) revealed no significant difference.

CONCLUSION

RTSA with a cementless and metaphyseal stem fixation represents a safe and feasible treatment for complex PHFs with a medial calcar fragment when this may be fixed with a steel wire cerclage.

Cemented vs. uncemented reverse total shoulder arthroplasty for the primary treatment of proximal humerus fractures in the elderly-a retrospective case-control study

BACKGROUND

Uncemented reverse total shoulder arthroplasty (RTSA) for the primary treatment of proximal humerus fractures (PHF) in elderly patients was introduced at our institution in 2017. Recent reports have raised concerns about increased rates of early bone resorption at the proximal humerus with uncemented fracture stems. The aim of this study was to find out whether there was any difference in functional or radiographic outcomes between cemented and uncemented RTSA for PHF.

METHODS

Seventeen consecutive patients who underwent uncemented RTSA (group nC) in 2017 and 2018 were age and sex matched (propensity score matching 1:2) to 34 patients with cemented RTSA implanted between 2011 and 2016 (group C) for the primary treatment of PHF. These two groups were compared in terms of clinical and radiographic outcomes at 2 years after the index surgery.

RESULTS

The mean bone quality was low in both groups: in group nC the deltoid tuberosity index (DTI) was 1.43 (1.22-1.72) and in group C 1.42 (1.22-1.67). At the final 2 year follow-up, the relative CS was 98.3% (71-118) in group nC and 97.9% (36-125) in group C (p = 0.927); the absolute CS was 70.2 (49-89) in group nC and 68.0 (30-94) in group C (p = 0.509). Lucent lines at the humeral site were seen in 8 cases (47%) in group nC and in 13 cases (38%) in group C (p = 0.056). Compared to 3% in group C, all patients in group nC showed at least grade 1 and 65% showed grade 3 bone resorption at the proximal humerus (p < 0.001).

CONCLUSION

Compared to cemented RTSA bone resorption at the proximal humerus was significantly more frequent in patients with uncemented RTSA for PHF. So far, this is rather a radiographic than a clinical finding, because both groups showed very satisfying functional outcomes and low revision rates at the 2 year follow-up.

LEVEL OF EVIDENCE III

A retrospective case-control study.

Clinical outcomes of cemented vs. uncemented reverse total shoulder arthroplasty for proximal humerus fractures: a systematic review

BACKGROUND

Reverse total shoulder arthroplasty is an established treatment method for comminuted proximal humerus fractures. Both cemented and uncemented techniques exist, with uncemented reverse total shoulder offering many theoretical advantages, including improved biologic fixation, absence of cement related complications, and ease of revision if necessary. There are few studies comparing the outcomes of the two techniques.

METHODS

The study was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. A search for studies assessing clinical outcomes of reverse total shoulder arthroplasty for proximal humerus fractures was performed of PubMed, Embase, Web of Science, and Cochrane Library. Main outcomes included Constant Score (CS), American Shoulder and Elbow Surgeons (ASES) score, and complication rate. Inclusion criteria were as follows: indication for arthroplasty was fracture; minimum one year follow up; article in English. Exclusion criteria were as follows: review articles; biomechanical or cadaver studies. Quality analysis was performed using the Cochrane Risk of Bias tool (RoB 2) and the Risk of Bias in Non-randomized Studies-of Interventions (ROBINS-I) tool.

RESULTS

A total of 682 studies were identified through the initial search, with 36 studies meeting all inclusion criteria. There were 24 studies investigating cemented technique, 10 studies examining uncemented technique, and two studies involving both techniques. There was no difference in mean follow up between patients receiving a cemented vs. uncemented rTSA (32.3 months vs. 30.6 months, p = 0.06). Patients who received a cemented rTSA had a significantly higher Constant-Murley score than those who received an uncemented rTSA (59.4 vs 55.9, p < .001). There was no difference between the two groups when comparing ASES Scores (77.5 vs 78.6, p = 0.54) and overall complication rates (11.1% vs 11.8%, p = 0.23).

CONCLUSION

Both cemented and uncemented rTSA are both valid options for treating acute proximal humerus fractures. Cemented rTSA may portend slightly improved clinical outcomes with similar overall complication rates compared to uncemented rTSA for proximal humerus fractures.

The Evolution of Reverse Total Shoulder Arthroplasty and Its Current Use in the Treatment of Proximal Humerus Fractures in the Older Population

Proximal humerus fracture (PHF) is a common injury in the older population. While the majority of these fractures are treated non-operatively, a small subset of patients may benefit from surgical treatment. However, there continues to be an ongoing debate regarding the indications and ideal surgical treatment strategy. The use of reverse total shoulder arthroplasty (RTSA) has resulted in a paradigm shift in the treatment of PHFs in the older population. Unique biomechanical principles and design features of RTSA make it a suitable treatment option for PHFs in the older population. RTSA has distinct advantages over hemiarthroplasty and internal fixation and provides good pain relief and a reliable and reproducible improvement in functional outcomes. As a result, there has been an exponential increase in the volume of RTSA in the older population in last decade. The aim of this paper is to review the current concepts, outcomes and controversies regarding the use of RTSA for the treatment of PHFs in the older population.

Short-term comparative outcomes between reverse shoulder arthroplasty for shoulder trauma and shoulder arthritis: a Southeast Asian experience

Background

Reverse shoulder arthroplasty (RSA), first introduced as a management option for cuff tear arthropathy, is now an accepted treatment for complex proximal humeral fractures. Few studies have identified whether the outcomes of RSA for shoulder trauma are comparable to those of RSA for shoulder arthritis.

Methods

This is a retrospective, single-institution cohort study of all patients who underwent RSA at our institution between January 2013 and December 2019. In total, 49 patients met the inclusion criteria. As outcomes, we evaluated the 1-year American Shoulder and Elbow Surgeons (ASES) and Constant shoulder scores, postoperative shoulder range of motion, intra- and postoperative complications, and cumulative revision rate. The patients were grouped based on preoperative diagnosis to compare postoperative outcomes across two broad groups.

Results

The median follow-up period was 32.8 months (interquartile range, 12.6–66.6 months). The 1-year visual analog scale, range of motion, and Constant and ASES functional scores were comparable between RSAs performed to treat shoulder trauma and that performed for arthritis. The overall complication rate was 20.4%, with patients with a preoperative diagnosis of arthritis having significantly more complications than those with a preoperative diagnosis of trauma (34.8% vs. 7.7%).

Conclusions

Patients who underwent RSA due to a proximal humeral fracture or dislocation did not fare worse than those who underwent RSA for arthritis at 1 year, in terms of both functional and radiological outcomes.

Use of a locking stem for reverse shoulder arthroplasty is a rare but reliable option

INTRODUCTION

RSA is widely used in the treatment of complex trauma or degenerative changes of the shoulder. Strong primary fixation of the stem is necessary to prevent any loosening of the stem and subsequent revision. Presently, cement fixation or press-fit fixation are two options for humeral fixation, though each has its own limitations and risks. The aim of the current study is to evaluate the effectiveness of an alternative option involving a distal screw interlocking system for fixation of the humeral stem from initial implantation.

METHODS

We performed a retrospective multicenter study of patients implanted with the Humelock Reversed® stem RSA that can be locked with distal humeral screws in cases of operative poor press fit or to modulate the lengthening of the arm via prosthetic humeral height. Seventy-two patients with a minimum two year follow-up were included, 13 for acute trauma, 42 for degenerative changes, and 17 for revision surgery.

RESULTS

No difference was seen in radiological or clinical results for patients with or without interlocking screw primary stabilization. For non-trauma patients, the mean raw Constant score improved significantly from 31 (± 12) to 71 (± 12). For trauma patients, the mean raw Constant score for trauma (63.4) was significantly lower than for non-trauma cases (72.1) (p < 0.001). Analysis of the filling ratio demonstrated that interlocking screws were not used for lower filling ratios and that midterm fixation of the stem is not negatively impacted by distal interlocking screw fixation.

DISCUSSION

Even if use of a distal interlocking screw fixation system is rare, it can be useful for patients with poor quality fixation of stemmed RSA.

CONCLUSION

Use of an interlocking screw system to stabilize the stem in RSA provides good immediate and midterm stability of the implant allowing for clinical and radiological outcomes comparable to those obtained with press-fit fixation alone.

Operative Treatment of Proximal Humeral Fractures with Reverse Total Shoulder Arthroplasty in Patients ≥65 Years Old: A Critical Analysis Review

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The majority of proximal humeral fractures (PHFs) in patients who are ≥65 years of age are treated nonoperatively, but certain complex fracture patterns benefit from surgical intervention. However, there continues to be debate regarding the indications for surgery and the optimal surgical treatment (repair versus replacement) in this population.

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Reverse total shoulder arthroplasty (RTSA) has grown in popularity for surgical treatment of fracture-dislocations and displaced complex PHFs in patients who are ≥65 years of age; it has definite advantages over surgical repair and hemiarthroplasty, but this finding requires additional higher-quality evidence.

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RTSA provides early pain relief and return of shoulder function as well as predictable elevation above shoulder level in the forward plane, but the indications for and understanding of the effect of timing on RTSA after a PHF continue to evolve.

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RTSA for an acute PHF is indicated in patients who are ≥65 years of age with 3- and 4-part fracture-dislocations, head-split fractures, and severely displaced fractures, and is an option in patients who are not able to tolerate nonoperative treatment of severely displaced 3- and 4-part fractures.

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RTSA is also indicated as a salvage operation for PHFs that have failed initial surgical repair (i.e., fixation failure, implant failure, rotator cuff failure, or osteonecrosis) and is an option for symptomatic nonunion or malunion after nonoperative treatment.

Cemented vs. uncemented reverse shoulder arthroplasty for proximal humeral fractures: a systematic review and meta-analysis

BACKGROUND

The purpose of this systematic review was to compare functional outcomes, complications, and revision rates between cemented and uncemented reverse shoulder arthroplasty (RSA) for proximal humeral fractures (PHFs).

METHODS

A systematic search was performed in April 2021 within PubMed, Scopus Web of Science, and Cochrane Library databases for clinical studies reporting outcomes of RSA performed for PHF. Included studies were published in English, had a minimum 1-year follow-up, specified whether the humeral stem was cemented (cRSA) or uncemented (ucRSA), and were evidence level I-IV. Data including range of motion (ROM), functional status, American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) score, Constant-Murley score, visual analog scale (VAS) score, tuberosity healing, complications, and reoperations were extracted. DerSimonian-Laird random effects models with subgroup stratification analyses were applied to investigate differences in outcomes between patients with cRSA and ucRSA.

RESULTS

A total of 45 studies comprising 1623 patients were included. The overall pooled age was 75.9 ± 3.4 years. At a mean follow-up of 34.6 (range, 12-108) months, there were no significant differences in ROM, VAS score, Constant-Murley score, rate of tuberosity healing, or reoperation rates between the cRSA and ucRSA cohorts. The mean postoperative ASES score in the cRSA cohort (73.9, 95% CI 71.4-76.5) was significantly lower than the ucRSA cohort (82.9, 95% CI 75.9-90.0, P = .013). The incidence of postoperative all-cause complications was significantly lower in the cRSA cohort (5.5%, 95% CI 4.0%-6.9%) compared with the ucRSA cohort (9.7%, 95% CI 4.5%-14.9%, P = .044).

CONCLUSION

The use of uncemented humeral stems in RSA for PHF confers similar functional results to the use of cemented stems in terms of pain, range of motion, functional scores, and tuberosity healing. Although the rate of complications was significantly higher in the uncemented cohort compared with the cemented cohort (9.7% vs. 5.5%, respectively), the rate of reoperations was similar between the groups (1.6% vs. 1.9%, respectively). The uncemented reverse prosthesis seems to be a valid alternative for the management of patients with complex proximal humerus fractures.

Cemented versus uncemented reverse shoulder arthroplasty for acute proximal humeral fractures

BACKGROUND

The purposes of this study were (1) to compare postoperative range of motion (ROM) and functional outcomes in patients with proximal humeral fractures operated on with cemented or uncemented reverse shoulder arthroplasty (RSA), (2) to compare the rate of tuberosity healing between cemented and uncemented stems, (3) to determine whether there are significant differences in functional outcomes between patients with healed tuberosities and those with unhealed tuberosities, and (4) to compare complications and revision rates in patients with cemented RSA and uncemented RSA.

METHODS

A cemented RSA was performed early in the study period, which represented a historical cohort (January 2015 to January 2017), followed by a transition to the uncemented RSA later in the study period (February 2017 to February 2019). We excluded 22 cases from postoperative evaluation because of fracture sequelae, age < 65 years, death, and institutionalization; 3 patients were lost to follow-up. The remaining 67 cases (32 cemented and 35 uncemented) underwent clinical and radiographic evaluation by 2 independent fellowship-trained shoulder surgeons. Patients were assessed regarding ROM and the visual analog scale for pain, American Shoulder and Elbow Surgeons score, Constant score, and Single Assessment Numeric Evaluation score. All intraoperative and postoperative complications were recorded.

RESULTS

The mean follow-up period was 41 months (range, 24-72 months), and the mean age was 74 years (range, 65-84 years). Mean postoperative active elevation, internal rotation, external rotation in abduction, and external rotation in adduction were 130° (±15°), 27° (±5°), 28° (±10°), and 16° (±6°), respectively. The mean postoperative visual analog scale, American Shoulder and Elbow Surgeons, Constant, and Single Assessment Numeric Evaluation scores were 1.8 (±0.8), 74 (±6), 58 (±11), and 74% (±8), respectively. There were no significant differences in final ROM and functional scores between the cemented and uncemented groups. The rate of tuberosity healing did not vary significantly in relation to whether the stem was cemented. The subgroup of patients with tuberosity healing presented significantly better active elevation, external rotation, and Constant scores than the subgroup without tuberosity healing. There were 5 complications (7%) and no cases of aseptic humeral stem loosening.

CONCLUSION

In the short term (mean, 41 months), there were no significant differences in postoperative ROM, functional outcomes, complications, and revisions between patients operated on with cemented RSA and those operated on with uncemented RSA for proximal humeral fractures. Patients with healed tuberosities presented significantly better ROM and functional scores than patients without tuberosity healing. The cementation of the stem did not significantly affect the rate of tuberosity healing.

Reverse shoulder arthroplasty for proximal humeral fracture in the elderly. Cemented or uncemented stem?

OBJECTIVE

The purposes of this study were to compare functional outcomes, radiographic stem changes and complication rate in patients with proximal humeral fractures operated with cemented or uncemented RSA.

METHODS

Retrospective review of 68 primary RSAs in PHF, 45 cemented/23 uncemented. Functional outcomes were evaluated according to constant, ASES scales and the range of motion (ROM). Radiographic assessment was performed at a minimum of two years post-operatively.

RESULTS

The mean follow-up cemented/uncemented was 37.8/26.5 months (p = .04) and the mean age 78/80 years old (p = .09). The functional outcome and range of movement were equivalent in the two groups except for the forward flexion that was significantly higher in the cemented group (p = .03). Stress shielding was seen in 30.4% of uncemented group and none in the cemented. Anatomic tuberosity healing was significantly higher with uncemented components compared with cemented components (64% vs 91%, p = .02). Cemented stems had radiolucent lines with a width of 2 mm or more in three or more Gruen zones in 9% vs 0% in the uncemented group and an evident change in the stem position was present in 4% vs 0% in the non-cemented group.

CONCLUSION

At mid-term follow-up, no differences in functional outcomes were detected depending on the stem fixation technique. Cemented stems, however, have a complication rate (including stem loosening) significantly higher than press-fit stems.

Prosthesis Designs and Tuberosity Fixation Techniques in Reverse Total Shoulder Arthroplasty: Influence on Tuberosity Healing in Proximal Humerus Fractures

Reverse total shoulder arthroplasty (RTSA) is increasingly used for the treatment of complex proximal humerus fractures and fracture sequelae. In 2021, half a dozen models of fracture stems are commercially available, reflecting its growing utility for fracture management. Prosthesis designs, bone grafting and tuberosity fixation techniques have evolved to allow better and more reliable fixation of tuberosities and bony ingrowth. Patients with anatomical tuberosity healing not only have an increased range of active anterior elevation and external rotation, but also experience fewer complications and longer prosthesis survival. This review provides an overview of recent evidence on basic and fracture-specific RTSA design features as well as tuberosity fixation techniques that can influence tuberosity healing.