Early clinical results of reverse total shoulder arthroplasty in the Korean population

Complications and Reinterventions of Reverse Total Shoulder Arthroplasty in a Korean Population: 14-Year Experience in Reverse Shoulder Arthroplasty

Background

There are few reports on the revision or reintervention of reverse total shoulder arthroplasty (RTSA) in South Korea. The purpose of this study was to evaluate the true incidence of complications and reintervention of RTSA and clinical and radiological outcomes based on our 14-year experience in RTSA in a Korean population.

Methods

Between March 2008 and June 2022, 412 consecutive cases of RTSA were performed in 388 patients with an average age of 74.4 years at our institute. Excluding 23 patients lost to follow-up, 365 patients (373 shoulders including 8 bilateral cases) who underwent primary RTSA with more than 6 months of follow-up were enrolled in this study. We evaluated those who had complications or reintervention including revision RTSA for failed RTSA. Patient charts were reviewed, and clinical outcomes including clinical scores, complications, and reintervention and radiologic outcomes were evaluated at the last follow-up.

Results

Among the 373 shoulders that underwent primary RTSA, complications were found in 50 patients (13.94%, 10 men and 40 women with a mean age of 75.9 ± 6.7 years [range, 51-87 years]). The causes of complications were as follows: 13 acromion, coracoid, or scapular spine fractures, 10 loosening (glenoid: 5, humeral stem: 5), 5 infections, 4 periprosthetic fractures, 2 instability, 2 neurologic complications, and 14 miscellaneous complications. Twenty patients (5.63%, 4 men and 16 women with a mean age of 74.2 ± 8.2 years [range, 51-87 years]) underwent reintervention. The interval to the first reintervention was 27.8 ± 23.1 months (range, 0.1-78 months). The causes of reintervention (20 cases) were 8 loosening (glenoid: 4, humeral stem: 4), 5 infections, 5 fractures, and 2 instability. Among them, 15 component revisions (4.02%) were performed. At the last follow-up, American Shoulder and Elbow Surgeons, University of California at Los Angeles, and Simple Shoulder Test scores were improved from 25.4, 12.4, and 1.6 preoperatively to 40.4, 16.2, and 3.2, respectively. Forward flexion (48° to 87°), abduction (52° to 79°), external rotation (18° to 22°), and internal rotation (buttock to L2) were improved.

Conclusions

After primary RTSA in a Korean population, the complication, reintervention, and revision rates were 13.94%, 5.63%, and 4.02%, respectively. Careful evaluation of the complications and adequate treatments should be performed.

Accuracy of detecting burst of the lateral wall in intertrochanteric hip fractures with plain radiographs: Is postoperative CT necessary?

Background

Postoperative burst of the lateral femoral wall is thought to be the main predictor of reoperation for intertrochanteric fractures, which is routinely evaluated using plain radiographs. We retrospectively compared computed tomography (CT) scans and radiographs regarding the ability to detect burst of the lateral wall. We also investigated whether intramedullary nails may cause iatrogenic burst of the lateral wall.

Methods

From January 2010 to December 2021, patients aged 65 years and older who undergone intertrochanteric fractures treated with the proximal femoral nail antirotation 2 (PFNA-Ⅱ) were included. The incidence of burst of the lateral wall was evaluated with two different imaging modalities by two observers. Two rounds of evaluation were performed: (1) with plain radiographs alone; and (2) with CT scans combined with radiographs. Interobserver and intraobserver agreement (κ value) for evaluation of the lateral wall burst was assessed.

Results

A total of 1507 patients were included (362 males and 1145 females). Compared with radiographs alone (12.0 %, 181/1507 patients), a higher rate of lateral wall burst was found by CT scans combined with radiographs (72.9 %, 1098/1507 patients) for observer 1 at first reading (P < 0.001). Similar results were seen in other evaluations. Interobserver and intraobserver agreement was substantial for radiographs alone (κ, 0.659-0.727) and almost perfect for CT scans combined with radiographs (κ, 0.847-0.926).

Conclusions

Computed tomography combined with radiographs is superior to radiographs alone for detecting burst of the lateral wall after intertrochanteric fracture fixation. Additionally, PFNA-Ⅱ could cause iatrogenic burst of the lateral wall for intertrochanteric fractures in the elderly.

Comparison of short-term clinical outcomes and radiographic changes in Grammont reverse shoulder arthroplasty between the French and Japanese populations: A propensity score-matched analysis

BACKGROUND

Although Grammont-style reverse total shoulder arthroplasty (RSA) showed excellent clinical results in Europe, its utility for Asian populations remains unclear. This study aimed to compare the French and Japanese populations in terms of range of motion (ROM), functional outcomes, and scapular notching rates in patients who underwent standard Grammont-style RSA. We hypothesized that RSA for the Japanese population may not provide as good ROM and functional results at the final follow-up as that for the French population.

METHODS

A total of 25 Japanese patients undergoing RSA were propensity score matched to 25 French patients undergoing RSA. The patients were matched for four different covariates using a propensity score analysis. The minimum follow-up period was 2 years. We investigated differences between the populations with respect to body size and shoulder joint ROM and Constant score (CS) measured preoperatively and at the final follow-up. Scapular notching was examined using radiographs at the final follow-up.

RESULTS

The average height and weight of the French and Japanese patients were 164 cm and 70 kg and 152 cm and 56 kg, respectively. Anterior elevation (AE), external rotation (ER) at the side, internal rotation (IR), and CS total changed from 101° to 145°, 17° to 15°, 4.5 points to 5.5 points, and 36 points to 72 points, respectively, in the French population and from 63° to 119°, 8.5° to 13°, 4.6 points to 4 points, and 28 points to 58 points, respectively, in the Japanese population. AE improved in both the groups; ER and IR remained unchanged before and after surgery. The frequency of scapular notching (>grade 1) was higher in the Japanese population (56%) than in the French population (20%) (p = 0.019).

CONCLUSIONS

Grammont-style RSA improved AE and CS in both the populations, but AE and CS were significantly higher in the French population than in the Japanese population at the final follow-up. Scapular notching frequently occurs in the Japanese population.

Effect of using a small baseplate on the radiological and clinical outcomes of reverse total shoulder arthroplasty in Asian patients

Aims

The aim of this study was to compare the clinical and radiological outcomes of reverse shoulder arthroplasty (RSA) using small and standard baseplates in Asian patients, and to investigate the impact of a mismatch in the sizes of the glenoid and the baseplate on the outcomes.

Methods

This was retrospective analysis of 50 and 33 RSAs using a standard (33.8 mm, ST group) and a small (29.5 mm, SM group) baseplate of the Equinoxe reverse shoulder system, which were undertaken between January 2017 and March 2021. Radiological evaluations included the size of the glenoid, the β-angle, the inclination of the glenoid component, inferior overhang, scapular notching, the location of the central cage in the baseplate within the vault and the mismatch in size between the glenoid and baseplate. Clinical evaluations included the range of motion (ROM) and functional scores. In subgroup analysis, comparisons were performed between those in whom the vault of the glenoid was perforated (VP group) and those in whom it was not perforated (VNP group).

Results

Perforation of the vault of the glenoid (p = 0.018) and size mismatch in height (p < 0.001) and width (p = 0.013) were significantly more frequent in the ST group than in the SM group. There was no significant difference in the clinical scores and ROM in the two groups, two years postoperatively (all p > 0.05). In subgroup analysis, the VP group had significantly less inferior overhang (p = 0.009), more scapular notching (p = 0.018), and more size mismatch in height (p < 0.001) and width (p = 0.025) than the VNP group.

Conclusion

In Asian patients with a small glenoid, using a 29.5 mm small baseplate at the time of RSA was more effective in reducing size mismatch between the glenoid and the baseplate, decreasing the incidence of perforation of the glenoid vault, and achieving optimal positioning of the baseplate compared with the use of a 33.8 mm standard baseplate. However, longer follow-up is required to assess the impact of these findings on the clinical outcomes.

Comparable outcomes of reverse shoulder arthroplasty for proximal humerus fractures and for rotator cuff arthropathy in a predominantly asian population

Background

Reverse shoulder arthroplasty (RSA) was initially developed for rotator cuff arthropathy but has been expanded to treat comminuted proximal humerus fractures. Few studies have compared RSA for traumatic and degenerative indications. We present the first report of mid-term outcomes of RSA comparing both indications in an Asian population.

Methods

113 degenerative and 20 fracture patients underwent RSA from 2010 to 2019. Patients with degenerative indications were 4:1 propensity-score matched to fractures and adjusted for age and sex. Patients were assessed for range of motion (ROM), strength, pain, Constant-Murley score (CMS), University of California Los Angeles Shoulder Score (UCLA) and Oxford shoulder score (OSS) preoperatively, at 6-months and 1-year. Patients' satisfaction, expectation fulfilment and minimal clinically important difference (MCID) were analysed.

Results

Degenerative patients had better ROM, isometric strength and CMS at 6-months, although at 1-year only abduction was superior (104.8  ±  17.3° vs 86.7  ±  19.8°). No significant differences in pain, UCLA and OSS were observed. Most improvements occurred within 6 months. Similar proportions of patients were satisfied (83.3% vs 73.3%, p = 0.460) and attained MCID (85.0% vs 86.7%, p = 1.000) at 1-year.

Discussion

Although initially exhibiting slower recovery, patients with proximal humerus fractures can expect similar functional recovery and satisfaction at 1-year compared to those who received RSA for degenerative indications.

Design of well-matched end-structure of anatomical proximal femoral locking plate based on computer-assisted imaging combined with 3D printing technology: a quality improvement study

BACKGROUND

The extramedullary locking plate system was the common internal fixation method for hip fractures. However, common plates were poorly matched to femur, which was because they were designed based on anatomical parameters of the Western populations. Therefore, the aim was to design an end-structure of the anatomical proximal femoral locking plate that closely matched the anatomy of the Chinese population.

MATERIALS AND METHODS

From January 2010 to December 2021, consecutive patients aged 18 years and older who underwent a full-length computed tomography scan of the femur were included. The end-structure (male and female model) of the anatomical proximal femoral locking plate was designed based on anatomical parameters of femurs that were measured in three-dimensional space using computer-assisted virtual technology. The match degree between the end-structure and femur were evaluated. Inter-observer and intra-observer agreement for the evaluation of match degree was assessed. The matching evaluation based on a three-dimensional printing model was regarded as the gold standard to assess the reliability.

RESULTS

A total of 1672 patients were included, with 701 men and 971 women. Significant differences were seen between male and female for all parameters of the proximal femur (all P <0.001). All match degree of end-structure was over 90%. Inter-observer and intra-observer agreement was almost perfect (all kappa value, >0.81). The sensitivity, specificity, and percentage of correct interpretation of matching evaluation in the computer-assisted virtual model was all greater than 95%. From femur reconstruction to completion of internal fixation matching, the process takes about 3 min. Moreover, reconstruction, measurement, and matching were all completed in one system.

CONCLUSIONS

The results showed that based on the larger sample of femoral anatomical parameters, a highly matching end-structure of anatomical proximal femoral locking plate for Chinese population could be designed with use of computer-assisted imaging technology.

Mid-term comparative study between the glenoid and humerus lateralization designs for reverse total shoulder arthroplasty: which lateralization design is better?

INTRODUCTION

The complications of the conventional medialized design for reverse total shoulder arthroplasty (RSA) are increased scapular notching, and decreased external rotation and deltoid wrapping. Currently, lateralization design RSA, which avoid scapular notching and improve impingement-free range of motion, is commonly used. Especially, humeral lateralization design was most commonly used and glenoid lateralization design was preferred for glenoid abnormities. We compared mid-term clinical and radiologic outcomes of glenoid and humeral lateralization RSA in an Asian population in this study.

MATERIALS AND METHODS

We enrolled 124 shoulders of 122 consecutive patients (mean age 73.8 ± 6.8 years) who received glenoid or humeral lateralization RSA from May, 2012 to March, 2019. We divided these patients into two groups according to RSA using either glenoid or humeral lateralization design. These different designs were introduced consecutively in Korea. The clinical and radiological results of 60 glenoid lateralization RSA (Group I, 60 patients) and 64 humeral lateralization RSA (Group II, 62 patients) were retrospectively evaluated and also were compared between the two groups. All patients were followed for mean 3 years.

RESULTS

The clinical and radiologic outcomes of the two groups did not differ significantly, including scapular notching (p = 0.134). However, humeral lateralization RSA showed a larger glenoid-tuberosity (GT) distance (p = 0.000) and less distalization shoulder angle (DSA) (p = 0.035). The complication rate did not differ significantly either. But, revision surgery was performed for 2 humeral loosening in the Group II.

CONCLUSION

The clinical and radiologic outcomes of the two groups did not differ significantly, including scapular notching at mid-term follow-up. However, humeral lateralization design showed larger GT distance and less DSA. Humeral lateralization design RSA could preserve the normal shoulder contour due to a larger GT distance (more lateralization) and provide less deltoid tension due to less DSA (less distalization of COR).

Surgeon-designed patient-specific instrumentation improves glenoid component screw placement for reverse total shoulder arthroplasty in a population with small glenoid dimensions

PURPOSE

Glenoid component loosening is a potential complication of reverse total shoulder arthroplasty (rTSA), occurring in part due to lack of adequate screw purchase in quality scapular bone stock. This study was to determine the efficacy of a surgeon-designed, 3D-printed patient-specific instrumentation (PSI) compared to conventional instrumentation (CI) in achieving longer superior and inferior screw lengths for glenoid component fixation.

METHODS

A multi-centre retrospective analysis of patients who underwent rTSA between 2015 and 2020. Lengths of the superior and inferior locking screws inserted for fixation of the glenoid baseplate component were recorded and compared according to whether patients received PSI or CI. Secondary outcomes included operative duration and incidence of complications requiring revision surgery.

RESULTS

Seventy-three patients (31 PSI vs. 42 CI) were analysed. Average glenoid diameter was 24.5 mm (SD: 3.1) and 81% of patients had smaller glenoid dimensions compared to the baseplate itself. PSI produced significantly longer superior (44.7 vs. 30.7 mm; P < 0.001) and inferior (43.0 vs. 31 mm; P < 0.001) mean screw lengths, as compared to CI. A greater proportion of maximal screw lengths for the given rTSA construct (48 mm) were observed in the PSI group (71.9% vs. 11.9% superior, 59.4% vs. 11.9% inferior). Operative duration was not statistically significantly different between the PSI and CI groups (150 min vs. 169 min, respectively; P = 0.229). No patients had radiographic loosening of the glenoid component with an average of 2-year follow-up.

CONCLUSION

PSI facilitates longer superior and inferior screw placement in the fixation of the glenoid component for rTSA. With sufficient training, PSI can be designed and implemented by surgeons themselves.

Clinical and Radiologic Outcomes of Small Glenoid Baseplate in Reverse Total Shoulder Arthroplasty: A Prospective Multicenter Study

Background

The purpose of this study was to evaluate the clinical and radiologic outcomes of reverse total shoulder arthroplasty (RTSA) using a small glenoid baseplate in patients with a small glenoid and to analyze the contributing factors to scapular notching.

Methods

A total of 71 RTSAs performed using a 25-mm baseplate were evaluated at a mean of 37.0 ± 3.3 months. Shoulder function was evaluated using American Shoulder and Elbow Surgeons (ASES) score, visual analog scale (VAS) for pain, Single Assessment Numeric Evaluation (SANE) for satisfaction, and active range of motion. Scapular neck angle (SNA), prosthesis-scapular neck angle (PSNA), peg glenoid rim distance (PGRD), and sphere bone overhang distance (SBOD) were measured to assess the effects on scapular notching.

Results

Shoulder function (ASES: 39.4 ± 13.8 preoperative vs. 76.2 ± 9.5 at last follow-up, p < 0.001), VAS for pain (6.1 ± 1.8 vs. 1.7 ± 1.4, p < 0.001), SANE for satisfaction (7.0 ± 11.8 vs. 83.4 ± 15.3, p < 0.001), and active forward flexion (115.6° ± 40.1° vs. 141.6° ± 17.2°, p < 0.001) were significantly improved. The mean diameter of the inferior glenoid circle was 26.0 ± 3.0 mm and the mean glenoid vault depth was 24.0 ± 4.5 mm. Scapular notching was found in 13 patients (18.3%) and acromial fracture in 2 patients (2.8%). There were no significant differences in preoperative SNA and PSNA at postoperative 3 years between patients with and without scapular notching (101.6° ± 10.5° and 110.8° ± 14.9° vs. 97.3° ± 13.3° and 104.9° ± 12.4°; p = 0.274 and p = 0.142, respectively). PGRD and SBOD were significantly different between patients with scapular notching and without scapular notching (24.8 ± 1.6 mm and 2.6 ± 0.5 mm vs. 21.9 ± 1.9 mm and 5.8 ± 1.9 mm; p < 0.001 and p < 0.001, respectively).

Conclusions

RTSA using a 25-mm baseplate in a Korean population who had relatively small glenoids demonstrated low complication rates and significantly improved clinical outcomes. Scapular notching can be prevented by proper positioning of the baseplate and glenosphere overhang using size-matched glenoid baseplates.

Complications and Intraoperative Fractures in Reverse Shoulder Arthroplasty: A Systematic Review

Introduction

The reverse shoulder arthroplasty is nowadays a treatment option for a variety of shoulder problems. As its incidence rose, also the number of complications increased, including intraoperative fractures.

Significance

We performed a systematic review and critical analysis of the current literature following the PRISMA guidelines. Our purpose was to: 1) determine incidence, causes, and characteristics of intraoperative fractures; 2) evaluate their current treatment options, possible related complications, reoperation rates, and the patients’ outcome; and 3) determine the overall incidence of each complication related to reverse shoulder arthroplasty. The articles were selected from PubMed medical database in April 2020 using a comprehensive search strategy. Rayyan software was used to support the selection process of the records. A descriptive and critical analysis of the results was performed.

Results

The study group included a total of 13,513 reverse shoulder arthroplasty procedures. The total number of complications was 1647 (rate 12.1%). The most common complication was dislocation (340 cases, rate 2.5%). Forty-six studies reported a total of 188 intraoperative fractures among the complications (rate 1.4%). The intraoperative fracture rate was 2.9% and 13.6% in primary and revision settings, respectively. There were 136 humeral fractures, 60% of them occurred in revision RSAs, during the removal of the previous implant, and involved the shaft in the majority of cases (39%). Glenoid fractures were 51 and occurred mostly during the reaming of the glenoid. We observed 7 further related complications (rate of 4%) and 3 reoperations (rate of 1.5%). The outcome was satisfactory in the majority of cases.

Conclusions

A comprehensive review on intraoperative fractures in reverse shoulder arthroplasties is presented. Results suggest favorable outcomes for all treatment methods, with a modest further complication rate. This investigation may aid in the treatment decision-making for these complications.

Mid-term outcomes of bony increased offset-reverse total shoulder arthroplasty in the Asian population

Background

To evaluate clinical and radiological outcomes of bony increased offset-reverse total shoulder arthroplasty (BIO-RSA) in the Asian population at mid-term follow-up.

Methods

From June 2012 to August 2017 at a single center, 43 patients underwent BIO-RSA, and 38 patients with minimum 2 years follow-up were enrolled. We evaluated the clinical and radiological outcomes, and complications at the last follow-up. In addition, we divided these patients into notching and no-notching groups and compared the demographics, preoperative, and postoperative characteristics of patients.

Results

Visual analogue scale, American Shoulder and Elbow Surgeons, University of California-Los Angeles Shoulder Scale, and Simple Shoulder Test scores improved significantly from preoperative (5.00, 3.93, 1.72, 3.94) to postoperative (1.72, 78.91, 28.34, 7.66) (p<0.05) outcomes. All range of motion except internal rotation improved significantly at the final follow-up (p<0.05), and the bone graft was well-incorporated with the native glenoid in all patients (100%). However, scapular notching was observed in 20 of 38 patients (53%). In the comparison between notching and no-notching groups (18 vs. 20 patients), there were no significant differences in demographics, radiological parameters, and clinical outcomes except acromion-greater tuberosity (AT) distance (p=0.003). Intraoperative complications included three metaphyseal fractures and one inferior screw malposition. Postoperative complications included ectopic ossification, scapular neck stress fracture, humeral stem relaxation, and late infection in one case each.

Conclusions

BIO-RSA showed improved clinical outcomes at mid-term follow-up in Asian population. However, we observed higher scapular notching compared to the previous studies. In addition, adequate glenoid lateralization with appropriate humeral lengthening (AT distance) might reduce scapular notching.

The study of 2-dimensional computed tomography scans of the glenoid anatomy in relation to reverse shoulder arthroplasty in the Southern Chinese population

Background

Reverse shoulder arthroplasty is becoming an increasingly common surgical procedure in Hong Kong, as well as in many other countries worldwide. The aim of this study is to describe the glenoid anatomy in the Southern Chinese population. We are interested to know whether commercially available glenoid implants are suitable for this population and whether there are any steps or precautions we can take during surgery to optimize the clinical outcome for these patients.

Method

A total of 244 shoulders of Southern Chinese patients were analyzed using 2-dimensional computed tomography, formatted to align along the scapular axis. The anatomic parameters analyzed included the shape, axial configuration, maximum width, maximum height, version, and presence of bone defect.

Results

In our study, 76.6% of glenoids were pear-shaped, 23.0% were elliptical, and only 0.4% were inverted pear in shape. Of all glenoids, 95.1% of glenoids had posterior-prominent axial configuration, whereas 4.9% had neutral axial configuration. The mean maximum glenoid height for both genders was 33.8 mm, whereas the mean maximum glenoid height was 32.2 mm for women and 36.6 mm for men. The mean maximum glenoid width for both genders was 25.8 mm, whereas the mean maximum glenoid width was 24.8 mm for women and 27.3 mm for men. The differences in measurements between genders were statistically significant. Of all glenoids, 46.3% of the glenoids were retroverted, whereas 53.7% of the glenoids were anteverted. The mean version for both genders was 0.77 degrees anteversion. The mean version was 1.16 degrees anteversion for women and 0.10 degrees anteversion for men. Of the 244 glenoids, 4 had bone defects. In our study, 39.8% of patients had mean maximum glenoid widths that were less than 25 mm, which is the smallest size available for most conventional glenoid baseplates.

Conclusion

A significant portion of the Southern Chinese population has glenoid widths that are smaller than the smallest commercially available glenoid baseplates. Understanding the glenoid anatomy is crucial in the case of reverse shoulder arthroplasty, as it has significant implications in implant design, operative planning, and surgical outcomes.

The modern reverse shoulder arthroplasty and an updated systematic review for each complication: part II

Background

Globally, reverse shoulder arthroplasty (RSA) has moved away from the Grammont design to modern prosthesis designs. The purpose of this study was to provide a focused, updated systematic review for each of the most common complications of RSA by limiting each search to publications after 2010. In this part II, the following were examined: (1) instability, (2) humerus/glenoid fracture, (3) acromial/scapular spine fractures (AF/SSF), and (4) problems/miscellaneous.

Methods

Four separate PubMed database searches were performed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Overall, 137 studies for instability, 94 for humerus/glenoid fracture, 120 for AF/SSF, and 74 for problems/miscellaneous were included in each review, respectively. Univariate analysis was performed with chi-square and Fisher exact tests.

Results

The Grammont design had a higher instability rate vs. all other designs combined (4.0%, 1.3%; P < .001), and the onlay humerus design had a lower rate than the lateralized glenoid design (0.9%, 2.0%; P = .02). The rate for intraoperative humerus fracture was 1.8%; intraoperative glenoid fracture, 0.3%; postoperative humerus fracture, 1.2%; and postoperative glenoid fracture, 0.1%. The rate of AF/SSF was 2.6% (371/14235). The rate for complex regional pain syndrome was 0.4%; deltoid injury, 0.1%; hematoma, 0.3%; and heterotopic ossification, 0.8%.

Conclusions

Focused systematic reviews of recent literature with a large volume of shoulders demonstrate that using non-Grammont modern prosthesis designs, complications including instability, intraoperative humerus and glenoid fractures, and hematoma are significantly reduced compared with previous studies. As the indications continue to expand for RSA, it is imperative to accurately track the rate and types of complications in order to justify its cost and increased indications.

The modern reverse shoulder arthroplasty and an updated systematic review for each complication: part I

Background

Globally, reverse shoulder arthroplasty (RSA) has moved away from the Grammont design to modern prosthesis designs. The purpose of this 2-part study was to systematically review each of the most common complications of RSA, limiting each search to publications in 2010 or later. In this part (part I), we examined (1) scapular notching (SN), (2) periprosthetic infection (PJI), (3) mechanical failure (glenoid or humeral component), and (4) neurologic injury (NI).

Methods

Four separate PubMed database searches were performed following Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Overall, 113 studies on SN, 62 on PJI, 34 on mechanical failure, and 48 on NI were included in our reviews. Univariate analysis was performed with the χ² or Fisher exact test.

Results

The Grammont design had a higher SN rate vs. all other designs combined (42.5% vs. 12.3%, P < .001). The onlay humeral design had a lower rate than the lateralized glenoid design (10.5% vs. 14.8%, P < .001). The PJI rate was 2.4% for primary RSA and 2.6% for revision RSA. The incidence of glenoid and humeral component loosening was 2.3% and 1.4%, respectively. The Grammont design had an increased NI rate vs. all other designs combined (0.9% vs. 0.1%, P = .04).

Conclusions

Focused systematic reviews of the recent literature with a large volume of RSAs demonstrate that with the use of non-Grammont modern prosthesis designs, complications including SN, PJI, glenoid component loosening, and NI are significantly reduced compared with previous studies. As the indications for RSA continue to expand, it is imperative to accurately track the rates and types of complications to justify its cost and increased indications.

3D CT scan-based study of glenoid morphology in Indian population: Clinical relevance in design of reverse total shoulder arthroplasty

BACKGROUND

The knowledge of normal anatomy of glenoid in a population has relevance in terms of comparison with other regional and national population. Furthermore, it could enable clinicians to judge whether the available sizes of reverse total shoulder arthroplasty (RTSA) prosthesis could provide optimal fit for the glenoid in Indian patients.

METHODS

We evaluated consecutive 200 3-dimensional chest CT scans of 50 male and 50 female patients which included both shoulder joints and done for non-orthopaedic diseases at a tertiary care institute. The glenoid height, width, and version were measured using commercially available computer program.

RESULTS

Mean age of the patents was 38.6 ± 13.8 years (range, 19-59 years). The mean glenoid height was 33.9 ± 3.1 mm and maximum glenoid width was 24.2 ± 2.1 mm. Mean glenoid version in the study population was a retroversion of 3.47 ± 4.7°. The maximum glenoid width of 45% female and 15% male patients was less than 25 mm which is the diameter of smallest available glenoid baseplate among the commonly used RTSA systems.

CONCLUSIONS

The normal glenoid size of a large cohort of Indian population studied was smaller than that reported in cohorts from western countries. The glenoid width of substantial proportion of patients, especially female patients, was less than the diameter of smallest available glenoid baseplate. Clinical studies are needed in future in Indian patients undergoing RTSA to evaluate the glenoid bone-baseplate mismatch and ascertain the necessity of development of smaller size glenoid baseplate for optimal prosthesis fit in Indian patients.

Measurement of talar morphology in northeast Chinese population based on three-dimensional computed tomography

Morphological data of talus are important for the design of talar prostheses. The talar morphology of Chinese population has been rarely reported. This study adopted a three-dimensional (3D) measurement approach to provide accurate data for the anatomical morphology of talus in Northeast Chinese population and compared it with that of foreigners.One hundred forty-six healthy subjects form Northeast China underwent computed tomography (CT) arthrography. 3D digital talar model was reconstructed and thirteen morphological parameters were measured through Mimics and Magics software. Length and breadth indexes of total talus, trochlea, medial and lateral malleolus articular surface were mainly selected. Statistical analysis was conducted by independent-samples and paired-samples t test through SPSS software.All the indexes were normally distributed. No significant difference between left and right talus was identified in either males or females (P > .05). Most of the indexes showed significant sexual differences except the radian of lateral malleolus articular surface and the posterior breadth of trochlea (P < .05). The talar anatomy of Chinese subjects is different from the published data in other populations.The promising approach adopted in this study addresses some inconvenience with previous conventional methods on cadaver specimens. The geometric parameters of talus in Chinese population differ from those in other populations. The talar measurements and morphology analysis in this study suggest that population characteristics should be taken into account. This study will provide references for the design of talar prostheses in Chinese population.

Three-dimensional measurement of glenoid dimensions and orientations

BACKGROUND

Asians generally have smaller stature than Europeans and Americans, and currently available implants used in reverse shoulder arthroplasty might not fit smaller bony anatomies. However, few articles have reported glenoid geometry in the Asian population. The purpose of this study was to measure the dimensions and orientations of the glenoid from three-dimensional computed tomography reconstructions of elderly Japanese subjects.

METHODS

This study included 100 shoulders (50 males and 50 females with >50 years of age). The mean age was 67 ± 7 years for both sexes, and the mean height was 167 ± 7 cm for males and 154 ± 6 cm for females. Three-dimensional scapular models were created from computed tomographic images, and the glenoid height, glenoid width, glenoid version, glenoid inclination, vault depth, and vault width were measured.

RESULTS

The mean glenoid height and width were 38.6 and 29.4 mm for males and 33.1 and 24.4 mm for females, respectively. Both retroversion and superior inclination were approximately 3° in both sexes. The glenoid vault was deeper in the posterior region with the maximum depth of 26.1 and 23.6 mm in males and females. The vault width was narrower in the anterior region with the anterior width of 2.5 mm at 15 mm medial from the glenoid face in females.

CONCLUSION

Glenoids of Japanese females are small compared to currently available baseplates for reverse shoulder arthroplasty. These results may be helpful to aid design in smaller baseplates that better fit the anatomic geometry of the Asian glenoid.

How common are acromial and scapular spine fractures after reverse shoulder arthroplasty?: A systematic review

AIMS

Acromial fractures following reverse shoulder arthroplasty (RSA) have a wide range of incidences in reported case series. This study evaluates their incidence following RSA by systematically reviewing the current literature.

MATERIALS AND METHODS

A systematic review using the search terms "reverse shoulder", "reverse total shoulder", or "inverted shoulder" was performed using PubMed, Web of Science, and Cochrane databases between 1 January 2010 and 31 March 2018. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used. Studies were included if they reported on RSA outcomes and the incidence rate of acromial and/or scapular spine fractures. The rate of these fractures was evaluated for primary RSA, revision RSA, RSA indications, and RSA implant design.

RESULTS

The review included 90 articles out of 686 identified after exclusions. The incidence rate of acromial and/or scapular spine fractures was 2.8% (253/9048 RSAs). The fracture rate was similar for primary and revision RSA (2.8% vs 2.1%; p = 0.4). Acromial fractures were most common after RSA for inflammatory arthritis (10.9%) and massive rotator cuff tears (3.8%). The incidence was lowest in RSA for post-traumatic arthritis (2.1%) and acute proximal humerus fractures (0%). Lateralized glenosphere design had a significantly higher rate of acromial fractures compared with medial glenosphere designs.

CONCLUSION

Based on current English literature, acromial and/or scapular spine fractures occur at a rate of 2.8% after RSA. The incidence is slightly more common after primary compared with revision arthroplasty. Also, higher rates of acromial fractures are reported in RSA performed for inflammatory arthritis and in the lateralized glenoid design. Cite this article: Bone Joint J 2019;101-B:627-634.

Shoulder arthroplasty after prior anterior stabilization procedures: do reverses have better outcomes?

BACKGROUND

Few studies have focused on shoulder arthroplasty after anterior stabilization procedures. This study compares the outcomes of total shoulder arthroplasty (TSA) and reverse total shoulder arthroplasty (RTSA) after anterior stabilization surgical procedures.

METHODS

All primary shoulder arthroplasties from 2000 to 2014 with prior surgery were retrospectively reviewed from a prospective research database. The inclusion criteria were primary TSA or RTSA, a history of anterior stabilization surgery, and minimum 2-year follow-up. Soft-tissue and bony anterior stabilization procedures were included. We compared the following between TSA and RTSA patients: active range of motion (ROM) and Shoulder Pain and Disability Index 130; Simple Shoulder Test; American Shoulder and Elbow Surgeons (ASES); Short Form 12; University of California, Los Angeles; and Constant scores. The RTSA group was also compared with an RTSA control group.

RESULTS

The study included 15 TSA and 10 RTSA patients with average follow-up periods of 3.3 and 4.0 years, respectively. RTSA patients experienced greater improvements in all ROMs except internal rotation; these were not statistically significant despite the mean values for RTSA being above the minimal clinically important difference compared with TSA for forward flexion and abduction. RTSA patients had better improvements in all functional outcomes; only the ASES score was statistically significant. TSA patients had a 33% complication rate and a 20% reoperation rate. RTSA patients had no complications or reoperations. The group that underwent RTSA with prior anterior stabilization surgery had similar improvements in ROM and outcome measures to the RTSA control group.

CONCLUSION

RTSA patients had better postoperative improvement in most ROMs and all functional scores; only the ASES score was statistically significant. This study suggests better outcomes with a lower complication rate with RTSA after prior anterior stabilization procedures compared with TSA.

Rationale for Small Glenoid Baseplate: Position of Central Cage within Glenoid Vault (Exactech® Equinoxe® Reverse System)

Background

Glenoid baseplate location is important to good clinical outcomes of reverse total shoulder arthroplasty (RTSA). The glenoid vault is the determining factor for glenoid baseplate location, but, to date, there are no reports on the effect of central cage location within the glenoid vault on RTSA outcomes when using the Exactech^® Equinoxe^® Reverse System. The purpose of this study was to determine the appropriate cage location in relation to the glenoid vault and monitor for vault and/or cortex penetration by the cage.

Methods

Data were retrospectively collected from the Samsung Medical Center (SMC) and Seoul National University Bundang Hospital (SNUBH). Patients who underwent RTSA between November 2016 and February 2018 were enrolled. Glenoid vault depth, central cage location within the vault were examined. Inferior glenoid rim–center distance, inferior glenoid rim–cage distance, and center–cage center distances were collected.

Results

Twenty-two patients were enrolled. Three SNUBH patients had inappropriate central cage fixation (33.3%) versus 4 SMC patients (30.8%). All cage exposures were superior and posterior to the glenoid vault. Mean center–cage distance was 5.0 mm in the SNUBH group and 5.21 mm in the SMC group. Center–prosthesis distance was significantly longer in the inappropriate fixation group than in the appropriate fixation group (p<0.024).

Conclusions

To ensure appropriate glenoid baseplate fixation within the glenoid vault, especially in a small glenoid, the surgeon should place the cage lower than usually targeted, and it should overhang the inferior glenoid rim.

Outcomes of reverse shoulder arthroplasty in small- and large-stature patients

BACKGROUND

As the worldwide use of reverse shoulder arthroplasty (RSA) increases, a range of implant sizes may be required to match regional and ethnic variation in patients' stature. Size-mismatched implants may possibly result in poorer surgical outcomes. The purpose of this study was to compare the outcomes of primary RSA in patients at the extreme ends of the growth curve with those in average-stature patients in the United States.

METHODS

A multicenter shoulder arthroplasty database was retrospectively reviewed to identify all primary RSAs using a single implant system with a minimum 2-year follow-up. Small patients were defined as the height of <155 cm, tall as >183 cm, and average as 162-178 cm. Active range of motion (ROM), visual analog scale pain score, and patient-reported outcomes (PROs) were compared among the 3 groups.

RESULTS

The study included 552 shoulders (130 small, 384 average, and 38 tall stature). Preoperatively, the average height group had significantly less ROM than the other groups, but there were no significant differences in postoperative ROM. This resulted in poorer improvements in postoperative ROM in the small and tall groups, with the small-stature patients having significantly less ROM improvement compared with average-stature patients. However, these differences did not result in poorer PROs between groups.

DISCUSSION

Small- and large-stature patients showed inferior improvements in ROM after RSA compared with average-stature patients. Our results suggest that current implants optimize ROM gains for average-stature patients and improve PROs independently of patient stature at a minimum 2-year follow-up.

Three-dimensional assessment of the normal Japanese glenoid and comparison with the normal French glenoid

INTRODUCTION

In 2014, reverse total shoulder arthroplasty was approved in Japan. We were concerned that the base plate might be incompatible with Japanese who were generally smaller than Westerners. Therefore, we investigated the dimensions and morphology of the normal Japanese glenoid and compared with the normal French glenoid.

MATERIALS AND METHODS

One hundred Japanese shoulders without glenoid lesions (50 men and 50 women) were investigated and compared with 100 French shoulders (50 men and 50 women). Computed tomography was performed with 3-dimensional image reconstruction and images were analyzed using Glenosys software. Glenoid parameters (width, height, retroversion and inclination) were compared between Japanese and French subjects.

RESULTS

In Japanese subjects, the mean glenoid width was 25.5mm, height was 33.3mm, retroversion was 2.3° and inclination was 11.6° superiorly. In French subjects, the mean glenoid width was 26.7mm, height was 35.4mm, retroversion was 6.0° and inclination was 10.4° superiorly. Glenoid width and height were significantly smaller in Japanese subjects than French subjects (P=0.001 and P<0.001), while retroversion was significantly greater in French subjects (P<0.001). There was no significant difference of inclination.

CONCLUSIONS

These findings will help surgeons to identify suitable patients for RSA and perform the procedure with appropriate preoperative planning.

LEVEL OF EVIDENCE

IV: retrospective or historical series.

Glenoid morphology and the safe zone for protecting the suprascapular nerve during baseplate fixation in reverse shoulder arthroplasty

PURPOSE

The purpose of this study was to investigate glenoid morphology and define the safe zone for protecting the suprascapular nerve baseplate screw during baseplate fixation in reverse shoulder arthroplasty (RSA) in a Chinese population.

METHODS

Shoulder computed tomography (CT) scans from 56 subjects were retrospectively reviewed. Three-dimensional (3D) reconstruction was performed using Mimics software, and corresponding bony references were used to evaluate glenoid morphology. To standardize evaluation, the coronal scapular plane was defined. Safe fixation distances and screw placements were investigated by constructing a simulated cutting plane of the baseplate during RSA.

RESULTS

Mean glenoid height was 35.83 ± 2.95 mm, and width was 27.32 ± 2.78 mm, with significant sexual dimorphism (p < 0.01). According to the cutting plane morphology, the average baseplate radius was 13.84 ± 1.34 mm. The distances from the suprascapular notch and from two bony reference points at the base of the scapular spine to the cutting plane were 30.27 ± 2.77 mm, 18.39 ± 1.67 mm and 16.52 ± 1.52 mm, respectively, with a gender-related difference. Based on the clock face indication system, the danger zone caused by the suprascapular nerve projection was oriented between the two o'clock and eight o'clock positions in reference to the right shoulder.

CONCLUSIONS

Glenoid size and the safe zone for screw fixation during RSA were characterized in a Chinese population. Careful consideration of baseplate fixation and avoidance of suprascapular nerve injury are important for improved clinical outcome.

The Dimensions of the Scapula Glenoid in Japanese Rotator Cuff Tear Patients

BACKGROUND

Reverse total shoulder arthroplasty has become a widely accepted surgical procedure in Japan since the time when the implants were approved for use in 2014. There is a doubt, however, as to whether the implants designed for Western people are suitable for Japanese people, particularly for females of relatively small stature. The purpose of this study was to investigate the glenoid dimension, with special focus on the length after glenoid reaming, in Japanese rotator cuff tear patients.

METHODS

Fifty-six shoulders of 55 patients (35 males and 20 females; mean age, 63.8 years) were studied. Using the three-dimensional computed tomography images of the entire scapula before shoulder surgery, we measured the glenoid height and width, and calculated the correlation between these measurements and the patient's height. Further, we measured the anteroposterior length of the scapular neck at the subchondral bone and the length at 15 mm medial to the subchondral bone, to simulate both the glenoid width after reaming (width of the 'virtual reamed surface') and the space available for the end of the center post of a standard glenoid baseplate.

RESULTS

The average glenoid height and width were 35.8 mm and 28.1 mm in males and 30.8 mm and 23.4 mm in females, respectively. There was a significant correlation between patient height and glenoid size (glenoid height, r = 0.69; width, r = 0.75; p < 0.01). The mean value of the width of the virtual reamed surface was 27.0 mm in males and 22.5 mm in females. The mean anteroposterior length at 15 mm medial to the subchondral bone was 12.4 mm in males and 9.5 mm in females; the length was shorter than 8 mm in 6 female shoulders.

CONCLUSIONS

There was a significant correlation between patient height and glenoid size. Considering that the common diameter of the commercially available baseplates and their center posts is greater than 25 mm and 8 mm, respectively, these prosthetic parts would be too large, especially for the Japanese female glenoid. Given that the current results of Japanese shoulder dimensions are similar to those of Asian people, 'Asian size implants' should be developed.

Geometric Analysis of the Proximal Humerus in Elderly Japanese Patients: Implications for Implant Selection in Reverse Shoulder Arthroplasty

The implants used in reverse shoulder arthroplasty were originally designed for white patients; thus, they might not be optimal for smaller Asian patients. The selection of reverse shoulder arthroplasty systems is limited in Japan. The purpose of this study was to measure the geometry of the proximal humerus in elderly Japanese patients to inform implant selection according to humerus size. This study included 155 shoulders from 148 patients 50 years or older who underwent computed tomography for shoulder disorders other than arthritis and trauma. There were 67 male and 81 female patients with mean ages of 68 and 66 years, respectively. The humeral head diameter, head height, neck-shaft angle, neck diameters, and osteotomy diameters for 155° inclination implants were measured using surface models created from computed tomography scans. The mean diameter of head curvature, humeral head height, and neck-shaft angle were 48.2 mm, 19.8 mm, and 136° for male patients and 42.4 mm, 17.1 mm, and 136° for female patients, respectively. The mean mediolateral and anteroposterior neck diameters were 46.9 mm and 43.7 mm for men and 41.6 mm and 38.4 mm for women, respectively. The mean mediolateral and anteroposterior osteotomy diameters were 42.2 mm and 41.2 mm for male patients and 38.6 mm and 36.7 mm for female patients, respectively. There were significant differences between the sexes in all measurements except neck-shaft angle. Humeral implants with 155° inclination will not fit the humerus of smaller Japanese women. Thus, implants with anatomical inclination and an onlay humeral tray may be a better choice for smaller patients. [Orthopedics. 2017; 40(3):e485-e490.].

Reverse shoulder arthroplasty for massive irreparable rotator cuff tears and cuff tear arthropathy: a systematic review

PURPOSE

To report the outcomes and complications of reverse shoulder arthroplasty (RSA) in massive irreparable rotator cuff tears (MIRCT) and cuff tear arthropathy (CTA).

METHODS

A systematic review of the literature contained in Medline, Cochrane, EMBASE, Google Scholar and Ovid databases was conducted on May 1, 2016, according to PRISMA guidelines. The key words "reverse total shoulder arthroplasty" or "reverse total shoulder prostheses" with "rotator cuff tears"; "failed rotator cuff surgery"; "massive rotator cuff tears"; "irreparable rotator cuff tears"; "cuff tear arthropathy"; "outcomes"; "complications" were matched. All articles reporting outcomes and complications of RSA for the management of MIRCT or CTA were included. The comparison between preoperative and postoperative clinical scores, as well as range of motion (ROM), was performed using the Wilcoxon-Mann-Whitney test. P values lower than 0.05 were considered statistically significant.

RESULTS

Seven articles were included in our qualitative synthesis. A statistically significant improvement in all clinical scores and ROM was found comparing the preoperative value with the postoperative value. The degrees of retroversion of the humeral stem of the RSA do not influence the functional outcomes in a statistically significant fashion. There were 17.4% of complications. The most frequent was heterotopic ossification, occurring in 6.6% of patients. Revision surgery was necessary in 7.3% of patients.

CONCLUSIONS

RSA restores pain-free ROM and improves function of the shoulder in patients with MIRCT or CTA. However, complications occur in a high percentage of patients. The lack of level I studies limits the real understanding of the potentials and limitations of RSA for the management of MIRCT and CTA.

Optimizing baseplate position in reverse total shoulder arthroplasty in small-sized Japanese females: technical notes and literature review

The management of cuff tear arthropathy (CTA) has always been a challenge for shoulder surgeons. Introduction of reverse total shoulder arthroplasty (RTSA) helped in providing pain relief and improved shoulder function in patients with CTA. In this study, we aimed to evaluate the short-term clinical results and some clinical details regarding the types of available prosthesis, positioning, and size of the components for RTSA in a population of short-stature female Japanese. In our seven cases, the average glenoid size was 23.9 mm in width and 34.2 mm in height. The average width was smaller than the size of all available baseplates. We implanted reverse shoulder prostheses with baseplate that measured 28 mm in diameter and two locking screws. The center of the baseplate was shifted to allow slight anterior overhang relative to the anatomical center to avoid breakage of the posterior cortex and to achieve firm fixation. One case of humeral shaft fracture occurred while inserting the humeral stem and required encircling wiring. In our experience, the short term clinical results of RTSA were excellent, but a new prosthesis that is designed to fit the short stature of Asians with smaller glenoid and humerus should be considered.

Distinct Proximal Humeral Geometry in Chinese Population and Clinical Relevance

BACKGROUND

Replicating humeral anatomy during shoulder arthroplasty is important for good patient outcomes. The proximal humeral geometry of the Chinese population has been rarely reported. We analyzed the geometry of the proximal part of the humerus in Chinese subjects and compared it with that of Western populations and the dimensions of available prostheses.

METHODS

Eighty healthy Chinese subjects underwent computed tomography (CT)-arthrography. Three-dimensional (3D) digital humeral and glenoid models were reconstructed, and geometric parameters were measured. Humeral measurements included the radius of curvature, articular surface diameter and thickness, anterior-posterior/superior-inferior (AP/SI) articular surface diameter ratio, articular surface thickness/radius of curvature ratio, surface arc, inclination angle, retroversion angle, and medial and posterior offsets. Glenoid measurements included SI length, AP length, SI radius, and AP radius.

RESULTS

The average radius of curvature (and standard deviation) of the humeral head was 22.1 ± 1.9 mm, the articular surface diameter averaged 42.9 ± 3.6 mm, and the articular surface thickness averaged 16.9 ± 1.5 mm. There was strong linear correlation between the articular surface diameter and thickness (r = 0.696, p = 0.001), with a linear regression relationship of thickness = 0.357 × diameter + 1.615. The AP/SI articular surface diameter ratio averaged 0.93 ± 0.03; the articular surface thickness/radius of curvature ratio, 0.77 ± 0.05; the surface arc, 153° ± 5.6°; the inclination angle, 133° ± 3.1°; and the retroversion angle, 22.6° ± 10.2°. The medial and posterior offsets averaged 6.3 ± 0.9 mm and 0.4 ± 0.78 mm, respectively; the SI and AP lengths, 30.15 ± 3.70 mm and 20.35 ± 2.56 mm; and the SI and AP radii, 23.49 ± 2.48 mm and 25.54 ± 3.07 mm. Compared with the Western population, the Chinese cohort had a smaller radius of curvature (p < 0.001), smaller articular surface diameter (p = 0.009), larger articular surface thickness/radius of curvature ratio (p < 0.001), larger surface arc (p < 0.001), smaller inclination angle (p < 0.001), and smaller posterior offset (p < 0.001). Unlike the Western population, the Chinese population had higher glenohumeral conformity in the coronal plane than in the axial plane. Many manufacturers' shoulder prostheses do not adequately cover the range of humeral head dimensions in our Chinese cohort.

CONCLUSIONS

The geometric parameters of the humeri in the Chinese population differ from those in other populations. These differences have clinical relevance with regard to implant design and arthroplasty technique and likely affect clinical outcomes.

Is there any influence of humeral component retroversion on range of motion and clinical outcome in reverse shoulder arthroplasty? A clinical study

PURPOSE

Reverse shoulder arthroplasty becomes more widely used as treatment for patients with complex cuff arthropathy. Theoretically, a higher retroversion of the humeral component leads to an increase in external rotation ROM and a decrease in internal rotation ROM. There is no consensus in optimal retroversion orientation. We retrospectively describe the effect of retroversion of the humeral component. We hypothesize that 20° humeral retroversion improves postoperative ROM, strength or clinical outcome scores compared to neutral retroversion.

METHODS

A retrospective clinical study is performed. An Aequalis reverse shoulder prosthesis was placed in 65 shoulders from 58 patients with a mean age of 73.8 years (95% CI 72.0-75.6). Between October 2006 and May 2012, the humeral component was placed in neutral retroversion in 36 shoulders (55%). From June 2012 to June 2014, it was placed in 20° retroversion in 29 shoulders (45%). After a mean follow-up of 36 months with a minimum of 12 months, patients were invited for a study visit. ROM, strength, Constant-Murley and Oxford Scores were measured.

RESULTS

ROM, strength and Constant-Murley and Oxford Scores did not differ significantly between both groups.

CONCLUSIONS

With the Aequalis prosthesis, no significant effect of 0° or 20° retroversion on external and internal rotation ROM, strength or functional outcome scores was found.

Are the Current Size Options of Glenoid Baseplates for Reverse Shoulder Arthroplasty Sufficient for our Local Population?

Background/Purpose

Reverse shoulder arthroplasty (RSA) is an effective treatment for patients who suffer from shoulder pain and dysfunction associated with a variety of shoulder pathologies including severe rotator cuff deficiency with or without glenohumeral arthritis. It has been widely used in European countries and the United States and is now gaining popularity in Asia, including Hong Kong. However, there are only limited size options available for glenoid baseplates, with 25 mm being the smallest size in some commonly used systems. The aim of our study is to perform computerized tomography (CT) measurements of the glenoid dimension in the Chinese population and to see if the current glenoid baseplate component size option is sufficient for our local population.

Methods

A total of 70 CT scans of shoulder regions were analysed. Measurements included maximum superoinferior height and the anteroposterior height.

Results

The glenoid dimensions were smaller compared to those from previous studies in Caucasian counterparts. Some 41% of female glenoids had widths measuring < 25 mm (25 mm being the smallest size available in some commonly used RSA systems).

Conclusion

Although there are only limited size options available for the glenoid baseplate in RSA, from our data, it should be able to cover most patients in our local population. However, surgeons should exercise special care when contemplating performing reverse shoulder replacement for small size females in our local population.

Reverse total shoulder arthroplasty for the management of fractures of the proximal humerus: a systematic review

Reverse total shoulder arthroplasty (RTSA) represents a good solution for the management of patients with fracture of the proximal humerus with associated severe osteoporosis and RC dysfunction. A systematic review of the literature according to the PRISMA guidelines was performed matching the following keywords: "reverse total shoulder arthroplasty"; "reverse total shoulder prostheses"; "fractures"; "fracture of the proximal humerus." Medline, EMBASE, Google Scholar, and Ovid database have been screened. Ten studies were considered in the qualitative analysis. No randomized prospective controlled trials have been found. A total of 256 patients received a RTSA for the management of fracture of the proximal humerus. There were 28 males (10.8 %) and 228 females (89.2 %). The mean age of patients was 75.5 ± 2.2 years (range 70-78 years). The mean follow-up period was 27.8 ± 21.8 months range (6-86 months). Overall, the mean Constant score was 56.7 ± 7.6 points (range 44-67.8 points), the mean DASH score was 39.9 ± 6 points (range 31.5-46.8 points), the ASES averaged 70.3 ± 6.8 points (range 65-78 points), and the OSS averaged 28.7 points (range 15-56 points). RTSA restores function and relieves pain in patients with proximal humeral fractures. However, no randomized controlled trials are available to support RTSA versus osteosintesis, anatomical prostheses or hemiarthroprotesis. Further studies are needed to evaluate the effectiveness of RTSA in the management of fracture of the proximal humerus.

Cemented or cementless humeral fixation in reverse total shoulder arthroplasty?

Aims

To date, there is insufficient evidence available to compare the outcome of cemented and uncemented fixation of the humeral stem in reverse shoulder arthroplasty (RSA).

Methods

A systemic review comprising 41 clinical studies was performed to compare the functional outcome and rate of complications of cemented and uncemented stems in RSA. These included 1455 cemented and 329 uncemented shoulders. The clinical characteristics of the two groups were similar. Variables were compared using pooled frequency-weighted means and relative risk ratios (RR).

Results

Uncemented stems had a significantly higher incidence of early humeral stem migration (p < 0.001, RR 18.1, 95% confidence interval (CI) 5.0 to 65.2) and non-progressive radiolucent lines (p < 0.001, RR 2.4, 95% CI 1.7 to 3.4), but a significantly lower incidence of post-operative fractures of the acromion compared with cemented stems (p = 0.004, RR 14.3, 95% CI 0.9 to 232.8). There was no difference in the risk of stem loosening or revision between the groups. The cemented stems had a greater relative risk of infection (RR 3.3, 95% CI 0.8 to 13.7), nerve injury (RR 5.7, 95% CI 0.7 to 41.5) and thromboembolism (RR 3.9, 95% CI 0.2 to 66.6). The functional outcome and range of movement were equivalent in the two groups.

Discussion

RSA performed with an uncemented stem gives them equivalent functional outcome and a better complication profile than with a cemented stem. The natural history and clinical relevance of early stem migration and radiolucent lines found with uncemented stems requires further long-term study. Take home message: This study demonstrates that uncemented stems have at least equivalent clinical and radiographic outcomes compared with cemented stems when used for reverse total shoulder arthroplasty. Cite this article: Bone Joint J 2016;98-B:65–74

Periprosthetic humeral fractures associated with reverse total shoulder arthroplasty: incidence and management

PURPOSE

The purpose of this study was to record the incidence and management of periprosthetic humeral fractures (PHF) using reverse total shoulder arthroplasty (RTSA) in our institution.

METHODS

We performed a retrospective study of 203 RTSA implanted in 200 patients between 2003 and 2014. The mean follow-up was 78.82 months (range, 12-141). Mean age of the study cohort was 75.87 years (range, 44-88). There were only 25 male patients (12.5 %). We assessed the presence of periprosthetic humeral fractures studying the medical files and X-rays of all patients.

RESULTS

We identified seven periprosthetic humeral fractures in 203 RTSA (3.4 %): three intra-operative (1.47 %) and four post-operative (1.97 %). The average age at the time of the fracture was 75.14 years (59-83). All patients were women (100 %). Three patients with post-operative fractures type B were treated by osteosynthesis, and one patient with post-operative fracture type A was treated conservatively. All intra-operative fractures needed cerclage wire and in one case long cemented stem. All our periprosthetic fractures healed.

CONCLUSIONS

Surgical treatment with osteosynthesis in type B post-operative fractures with a stable stem is recommended. Conservative treatment is sufficient in non-displaced type A post-operative fracture. Special attention should be paid to bone quality patients using non-cemented stems in primary surgery but especially in revision shoulder surgery.

Reverse shoulder arthroplasty: The Singapore General Hospital experience and a simple method of measuring change in the center-of-rotation

INTRODUCTION

This study reviews the outcomes of reverse shoulder arthroplasty (RSA) and introduces a novel method of measuring changes in the center-of-rotation (COR) of the shoulder joint post-operatively.

METHODS

We performed 10 reverse shoulders in 2011. Patients were evaluated pre-operatively and post-operatively using the Constant Score. The COR of the shoulder was determined pre- and post-operatively on radiographs and the differences were analysed.

RESULTS

There was significant improvement in Constant Scores post-operatively with reduction in pain and increase in strength. Medialisation but not distalisation of the COR was achieved.

DISCUSSION

Longer follow-up studies and studies on survivalship are required.

Effect of baseplate size on primary glenoid stability and impingement-free range of motion in reverse shoulder arthroplasty

Background

Use of a baseplate with a smaller diameter in reverse shoulder arthroplasty is increasing, especially in patients with a small glenoid or glenoid wear. However, the effect of a smaller baseplate on stability of the glenoid component has not been evaluated. Thus, the purpose of this study was to determine whether a smaller baseplate (25 mm) is beneficial to the initial stability of the glenoid component compared to that with a baseplate of a commonly used size (29 mm).

Methods

Micromotion of glenoid components attached to 14 scapulae of fresh-frozen cadavers was measured and compared between 25- and 29-mm baseplates in biomechanical testing. Impingement-free range of motion in abduction, adduction, internal rotation, and external rotation was evaluated by using a simulated computer model constructed based on the same fresh-frozen cadavers used in biomechanical testing.

Results

Micromotion at the inferior third of the glenoid-glenosphere interface was higher in the 29-mm baseplate group than in the 25-mm baseplate group during both 0.7- and 1-body weight cyclic loading in biomechanical testing. Adduction deficit was smaller, and total impingement-free range of motion from abduction to adduction and rotation were greater in the 25-mm baseplate group than in the 29-mm baseplate group in the simulated computer model.

Conclusions

Use of a baseplate with a smaller diameter (25 mm) in reverse shoulder arthroplasty is suitable for improving the primary stability of the glenoid component. With a smaller baseplate, impingement-free range of motion is optimized in a smaller glenoid.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2474-15-417) contains supplementary material, which is available to authorized users.

Uncemented versus cemented humeral stem fixation in reverse shoulder arthroplasty

PURPOSE

This study compares the radiographic and functional outcomes of uncemented and cemented humeral fixation in reverse total shoulder arthroplasty (RTSA).

METHODS

A prospective research database was reviewed for RTSA patients from 2007 to 2010. Inclusion criteria were primary RTSA from one manufacturer (Exactech Equinoxe®) with a grit-blasted metaphyseal humeral stem and two year minimum follow-up. Exclusion criteria included shoulder arthroplasty for fractures, fracture sequelae or inflammatory arthropathy. Radiographic and functional outcomes were compared between the uncemented and cemented groups.

RESULTS

A total of 97 patients (58 women, 39 men) with 100 RTSAs met the inclusion criteria. Radiographic and clinical two year follow-up was available in 80 % (51 RTSAs) of the uncemented group and 89 % (32 RTSAs) of the cemented group (mean follow-up 3.5 years). Average age at surgery was 72 years. Both groups showed significant improvements in the 12-item Simple Shoulder Test (SST-12), 12-item Short Form (SF-12), Shoulder Pain and Disability Index 130 (SPADI-130), American Society of Shoulder and Elbow Surgeons (ASES) score and normalised Constant scores. One humeral loosening was seen in each group (2 % uncemented, 3 % cemented). Both groups' overall component revision rate was 6 % (one in each group relating to humeral component failure). There were no significant differences in complication rates, change in functional scores and range of motion improvement.

CONCLUSIONS

Humeral component press-fitting in RTSA provides similar outcomes as cementation at a minimum two year follow-up.

Clinical outcomes of reverse total shoulder arthroplasty in patients aged younger than 60 years

BACKGROUND

Reverse total shoulder arthroplasty (RTSA) has been indicated primarily for patients aged older than 65 years with symptomatic rotator cuff deficiency, poor function, and pain. However, conditions that benefit from RTSA are not restricted to an elderly population. This study evaluates a consecutive series of RTSA patients aged younger than 60 years.

METHODS

We evaluated 36 shoulders (mean age, 54 years) at a mean follow-up of 2.8 years (range, 24-48 months). Of these shoulders, 30 (83%) had previous surgery, averaging 2.5 procedures per patient. The preoperative conditions compelling RTSA were as follows: failed rotator cuff repair (12), fracture sequelae (11), failed arthroplasty (5), instability sequelae (4), cuff tear arthropathy (CTA) (4), and rheumatoid arthritis (2). Follow-up examinations included range-of-motion and strength testing, as well as Single Assessment Numeric Evaluation, visual analog scale, Simple Shoulder Test, American Shoulder and Elbow Surgeons (ASES), and Constant scores. Preoperative and postoperative radiographs were reviewed for component loosening and scapular notching. Failure criteria were defined as undergoing revision, having gross loosening, or having an ASES score below 50.

RESULTS

The mean Single Assessment Numeric Evaluation score improved from 24.4 to 72.0; the visual analog scale pain score improved from 6 to 2.1. The Simple Shoulder Test score improved from 1.4 to 6.2, and the ASES score improved from 31.4 to 65.8. Active forward elevation improved from 56° to 121°. The normalized postoperative mean Constant score was 54.3. In 9 patients (25.0%), we recorded an ASES score below 50, and these cases were considered failures.

CONCLUSION

RTSA can improve shoulder function in a younger, complex patient population with poor preoperative functional ability. This study's success rate was 75% at 2.8 years. This is a limited-goals procedure, and longer-term studies are required to determine whether similar results are maintained over time.