Reverse total shoulder arthroplasty compared to stemmed hemiarthroplasty for proximal humeral fractures: a registry analysis of 5946 patients

Reverse Shoulder Arthroplasty for Proximal Humerus Fractures: A Review of Current Evidence

PURPOSE OF REVIEW

The aim of this review is to summarize information published in the recent peer-reviewed literature on reverse shoulder arthroplasty (RSA) for proximal humerus fractures.

RECENT FINDINGS

Although there is still some debate regarding which may be the best treatment for proximal humerus fractures in certain age ranges, RSA seems to offer more predictable results than other surgical treatments for elderly patients. Successful tuberosity healing seems to correlate with better outcomes. Recent trends indicate interest in cementless fixation, fracture-specific stems and a 135-degree polyethylene opening angle. RSA provides a successful surgical solution for selected proximal humerus fractures. Indications, design features, and surgical execution have continued to evolve over the last few years.

Geriatric proximal humerus fracture operative management: a Truven Health Analytics database study (2015-2020)

BACKGROUND

The purpose of this study is to assess the trends in operative management of geriatric (≥65 years) proximal humerus fractures during a 6-year period (2015-2020) within an insurance claims database.

METHODS

This retrospective database cohort study used data gathered from the 2015-2020 IBM Truven MarketScan Commercial and IBM Truven MarketScan Medicare Supplemental databases. The International Statistical Classification of Disease and Related Health Problems, Tenth Revision, data was correlated to the Current Procedural Terminology code for shoulder arthroplasty (proximal humeral prosthetic replacement: 23616, shoulder hemiarthroplasty [HA]: 23470, reverse total shoulder arthroplasty [rTSA]: 23472) or open reduction internal fixation (ORIF; open treatment of proximal humerus fracture with internal fixation: 23615, open treatment of proximal humerus fracture-dislocation with internal fixation: 23680). We investigated the number of proximal humerus fracture operative cases per year, percentage arthroplasty used per year, rTSA and HA per year, hospital cost information, as well as percentage arthroplasty per US geographic region.

RESULTS

A total of 8057 operative proximal humerus fractures cases were identified in 7697 patients aged >65 years, with 0.45% (360 of 8057) being bilateral. There was a 40.8% decrease in the rate of operative management of proximal humerus fractures between the first half (2015-2017, 1687.3 ± 146.6) and the second half of the study period (2018-2020, 998.3 ± 258.7). Arthroplasty accounted for 78.7% of all surgeries, 91% of those being rTSA. The total number of cases of rTSA and ORIF performed decreased per year (P = .01). The downward trend of percentage ORIF per year approached significance (P = .054). Arthroplasty was a more expensive option of payment for total case by almost $850.00 (P = .001). There was a larger percentage of arthroplasty performed in the Northeast and North Central US geographic regions.

CONCLUSION

Despite the rise of both the elderly population and related geriatric proximal humerus fractures, they were less operatively represented in this insurance claims database across the 6-year period. There may be a trend to use less ORIF when addressing these fractures. Although it incurred a higher in-hospital cost, arthroplasty was being performed at a higher percentage in the Northeast and North Central regions of the United States.

Does age affect patient outcomes after humeral head replacement in the treatment of acute proximal humeral fractures? A comparative cohort study with a minimum 10 years long-term follow-up

BACKGROUND

Humeral head replacement (HHR) is now rarely recommended for complex proximal humeral fractures (PHFs) in older patients. However, in relatively young and active patients with unreconstructable complex PHFs, controversy still exists regarding the treatment options of reverse shoulder arthroplasty and HHR. The goal of this study was to compare the survival, functional, and radiographic outcomes of HHR in patients aged <70 years and those aged ≥70 years after a minimum 10 years follow-up.

METHODS

Eighty-seven out of 135 patients undergoing primary HHR were enrolled and then divided into 2 groups based on age: <70 years and ≥70 years. Clinical and radiographic evaluations were performed with a minimum follow-up of 10 years.

RESULTS

There were 64 patients (mean, 54.9 years) in the younger group and 23 patients (mean, 73.5 years) in the older group. The younger and older groups had comparable 10-year implant survivorship (98.4% vs. 91.3%). Patients aged ≥70 years had worse American Shoulder and Elbow Surgeons scores (74.2 vs. 81.0, P = .042) and lower satisfaction rates (12% vs. 64%, P < .001) than younger patients. At the final follow-up, older patients had worse forward flexion (117° vs. 129°, P = .047) and internal rotation (17 vs. 15, P = .036). More greater tuberosity complications (39% vs. 16%, P = .019), glenoid erosion (100% vs. 59%, P = .077), and humeral head superior migration (80% vs. 31%, P = .037) were also identified in patients aged ≥70 years.

CONCLUSIONS

Unlike the increased risk for revision and functional deterioration over time after reverse shoulder arthroplasty for PHFs in younger patients, a high implant survival rate with lasting pain relief and stable functional outcomes could be observed in younger patients after HHR during long-term follow-up. Patients aged ≥70 years had worse clinical outcomes, lower patient satisfaction, more greater tuberosity complications, and more glenoid erosion and humeral head superior migration than those aged <70 years. HHR should not be recommended for the treatment of unreconstructable complex acute PHFs in older patient populations.

Primary reverse total shoulder arthroplasty for fractures requires more revisions than for degenerative conditions 1 year after surgery: an analysis from the Dutch Arthroplasty Register

BACKGROUND

Although reverse total shoulder arthroplasty (RTSA) is considered a viable treatment strategy for proximal humeral fractures, there is an ongoing discussion of how its revision rate compares with indications performed in the elective setting. First, this study evaluated whether RTSA for fractures conveyed a higher revision rate than RTSA for degenerative conditions (osteoarthritis, rotator cuff arthropathy, rotator cuff tear, or rheumatoid arthritis). Second, this study assessed whether there was a difference in patient-reported outcomes between these 2 groups following primary replacement. Finally, the results of conventional stem designs were compared with those of fracture-specific designs within the fracture group.

MATERIALS AND METHODS

This was a retrospective comparative cohort study with registry data from the Netherlands, generated prospectively between 2014 and 2020. Patients (aged ≥ 18 years) were included if they underwent primary RTSA for a fracture (<4 weeks after trauma), osteoarthritis, rotator cuff arthropathy, rotator cuff tear, or rheumatoid arthritis, with follow-up until first revision, death, or the end of the study period. The primary outcome was the revision rate. The secondary outcomes were the Oxford Shoulder Score, EuroQol 5 Dimensions (EQ-5D) score, numerical rating scale score (pain at rest and during activity), recommendation score, and scores assessing change in daily functioning and change in pain.

RESULTS

This study included 8753 patients in the degenerative condition group (mean age, 74.3 ± 7.2 years) and 2104 patients in the fracture group (mean age, 74.3 ± 7.8 years). RTSA performed for fractures showed an early steep decline in survivorship: Adjusted for time, age, sex, and arthroplasty brand, the revision risk after 1 year was significantly higher in these patients than in those with degenerative conditions (hazard ratio [HR], 2.50; 95% confidence interval, 1.66-3.77). Over time, the HR steadily decreased, with an HR of 0.98 at year 6. Apart from the recommendation score (which was slightly better within the fracture group), there were no clinically relevant differences in the patient-reported outcome measures after 12 months. Patients who received conventional stems (n = 1137) did not have a higher likelihood of undergoing a revision procedure than those who received fracture-specific stems (n = 675) (HR, 1.70; 95% confidence interval, 0.91-3.17).

CONCLUSION

Patients undergoing primary RTSA for fractures have a substantially higher likelihood of undergoing revision within the first year following the procedure than patients with degenerative conditions preoperatively. Although RTSA is regarded as a reliable and safe treatment option for fractures, surgeons should inform patients accordingly and incorporate this information in decision making when opting for head replacement surgery. There were no differences in patient-reported outcomes between the 2 groups and no differences in revision rates between conventional and fracture-specific stem designs.

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.

Impact of tobacco usage on readmission and complication rates following shoulder replacement surgery: A study of 164,527 patients

Background

Tobacco carcinogens have adverse effects on bone health and are associated with inferior outcomes following orthopedic procedures. The purpose of this study was to assess the impact tobacco use has on readmission and complication rates following shoulder arthroplasty.

Methods

The 2016-2018 National Readmissions Database was queried to identify patients who underwent anatomical, reverse, and hemi-shoulder arthroplasty. ICD-10 codes Z72.0 ×  (tobacco use disorder) and F17.2 ×  (nicotine dependence) were used to define "tobacco-users." Demographic, 30-/90-day readmission, surgical complication, and medical complication data were collected. Inferential statistics were used to analyze complications for both the cohort as a whole and for each procedure separately (i.e. anatomical, reverse, and hemiarthroplasty).

Results

164,527 patients were identified (92% nontobacco users). Tobacco users necessitated replacement seven years sooner than nonusers (p < 0.01) and were more likely to be male (52% vs. 43%; p < 0.01). Univariate analysis showed that tobacco users had higher rates of readmission, revisions, shoulder complications, and medical complications overall. In the multivariate analysis for the entire cohort, readmission, revision, and complication rates did not differ based on tobacco usage; however, smokers who underwent reverse shoulder arthroplasty in particular were found to have higher 90-day readmission, dislocation, and prosthetic complication rates compared to nonsmokers.

Conclusion

Comparatively, tobacco users required surgical correction earlier in life and had higher rates of readmission, revision, and complications in the short term following their shoulder replacement. However, when controlling for tobacco usage as an independent predictor of adverse outcomes, these aforementioned findings were lost for the cohort as a whole. Overall, these findings indicate that shoulder replacement in general is a viable treatment option regardless of patient tobacco usage at short-term follow-up, but this conclusion may vary depending on the replacement type used.

Is there still a place for anatomic hemiarthroplasty in patients with high functional demands in primary, nonreconstructable proximal humeral fractures? A clinical and radiographic assessment

BACKGROUND

Vitality-threatening proximal humerus fractures often provide an indication for prosthetic treatment. We investigated the issue of how anatomic hemiprostheses perform in younger, functionally challenging patients with the use of a specific fracture stem and systematic tuberosity management in medium-term follow-up.

METHODS

Thirteen skeletally mature patients with a mean age of 64 ± 9 years and a minimum follow-up of 1 year after primary open-stem hemiarthroplasty for 3- and 4-part proximal humeral fractures were included. All patients were followed up regarding their clinical course. Radiologic follow-up included fracture classification, healing of tuberosities, proximal migration of the humeral head, evidence of stem loosening, and glenoid erosion. Functional follow-up included range of motion, pain, objective and subjective performance scores, complications, and return to sports rates. We statistically compared treatment success based on the Constant score between the cohort with proximal migration and the cohort with regular acromiohumeral distance by means of the Mann-Whitney U test.

RESULTS

After an average follow-up period of 4.8 years, satisfactory results were obtained. The absolute Constant-Murley score was 73.2 ± 12.4 points. The disabilities of the arm, shoulder, and hand score was 13.2 ± 13.0 points. Patients reported their mean subjective shoulder value as 86.6% ± 8.5%. Pain was reported as 1.1 ± 1.3 points on a visual analog scale. Flexion, abduction, and external rotation values were 138 ± 31°, 134 ± 34°, and 32 ± 17°, respectively. 84.6% of the referred tuberosities healed successfully. Proximal migration was observed in 38.5% of cases and was associated with worse Constant score results (P = .065). No patient showed signs of loosening. Mild glenoid erosion was apparent in 4 patients (30.8%). All patients who were interviewed and participated in sports before surgery were able to return to their primary sport after surgery and continued to do so during the final follow-up.

CONCLUSIONS

With narrow indications, use of a specific fracture stem and adequate tuberosity management, successful radiographic and functional results are presented after a mean follow-up of 4.8 years after hemiarthroplasty for primary nonreconstructable humeral head fractures. Accordingly, open-stem hemiarthroplasty appears to remain a possible alternative to reverse shoulder arthroplasty in younger, functionally challenging patients with primary 3- or 4-part proximal humeral fractures.

Two-year clinical and radiographic outcomes following uncemented reverse shoulder replacements for proximal humerus fractures

BACKGROUND

Uncertainty remains regarding the role and long-term outcomes following uncemented reverse shoulder replacements (RSRs) in managing displaced proximal humeral fractures (PHFs). Although RSRs for trauma have traditionally undergone cemented fixation of the humeral component, there is increasing interest in uncemented RSRs. Our primary aim was to evaluate 2-year outcomes following uncemented RSR fixation for 3- and 4-part PHFs in the elderly. A secondary aim was to evaluate if timing of surgery affected outcomes.

METHODS

This cohort series evaluated 2-year outcomes for 42 patients with Neer 3- and 4-part PHFs treated with uncemented RSRs between October 2016 and December 2019. Thirty-eight patients (90%) had clinical and radiologic follow-up at a minimum of 2 years. The primary outcomes compared postoperative range of movement, radiographic outcomes, and patient-reported outcome measures (PROMs). The PROMs collected included Oxford Shoulder Scores (OSSs), satisfaction scores, and the Friends and Family Test. The secondary outcome involved a subanalysis to see if outcomes were affected by treatment timing-within 2 weeks, 2-12 weeks, and >12 weeks.

RESULTS

The mean age of patients was 74.1 years (range 58-89). There were 11 males and 31 females. No intraoperative fractures were sustained. There was 1 transient axillary neurapraxia, which fully resolved by 4 months. Three patients required postoperative transfusions. During the study follow-up period, no patients developed either deep infections requiring a washout or dislocation, and none underwent further surgery. At 2-year follow-up, radiologic follow-up demonstrated tuberosity union in 29 of 38 cases (76%). Eight of 38 patients (21%) demonstrated some glenoid notching (Sirveaux 1 or 2 only) on radiographic follow-up. There was no evidence of loosening. The mean OSS was 38 (range 15-48). Mean range of movement achieved at 2 years was as follows: forward flexion 122° (50°-180°), abduction 116° (46°-180°), and external rotation 25° (range 5°-60°). Eighteen patients (47%) described their result as excellent, 17 (45%) as good, and 3 (8%) as poor. When comparing the time from injury to treatment, there was no statistically significant difference in complications or radiographic outcomes between the groups. Patients had a reduced forward flexion when treated between 2 and 12 weeks compared with the other groups (P = .019).

CONCLUSION

Uncemented RSR is a safe treatment option for the management of complex PHFs in the elderly. We report low complication rates, high patient satisfaction, and good outcomes at 2-year follow-up.

What is the middle term survival of reverse shoulder arthroplasty? A retrospective observational registry-based study

PURPOSE

The use of reverse total shoulder arthroplasty has increased over the last decade. Like any other implant it is associated with complications sometimes leading to revision. We carried out a registry-based study in order to find possible risk factors associated with the need of revision surgery.

METHODS

The RIPO registry was analyzed from July 2008 to December 2018 collecting available data. Two groups (degenerative or fracture) were formed and compared to determine possible risk factors difference in revision surgery.

RESULTS

A total of 7,966 shoulder prosthesis were implanted. There was a 1.5% intra or peri-operative complication rate. The revision rate was 4.0% at a mean follow-up of 4.4 years. A total of 3,073 reverse total shoulder prosthesis were implanted and available for follow-up. An increase of revision rate (the most frequent causes being aseptic loosening, infection and instability) was found in patients younger than 65 years and in male patients. Two groups were then formed on the basis of the primary diagnosis: osteoarthritis and proximal humerus fracture. Comparison between the two groups showed an increase in instability requiring revision in the fracture group.

CONCLUSION

Reverse shoulder prosthesis is a valid treatment option both in the elective and in the trauma settings, but young and male patients should be informed of the inherently increased risk of revision and prosthesis used in the fracture setting should be evaluated more thoroughly to prevent instability.

Risk of Revision Shoulder Arthroplasty After Anatomic and Reverse Total Shoulder Arthroplasty

INTRODUCTION

The objective of this study was to determine the survivorship of anatomic total shoulder arthroplasty (aTSA) and reverse TSA (rTSA) over a medium-term follow-up in a large population-based sample and to identify potential risk factors for revision surgery.

METHODS

The State Inpatient Database from the Healthcare Cost and Utilization Project was used to identify patients who underwent aTSA or rTSA from 2011 through 2015 using ICD9 codes. We modeled the primary outcome of time to revision or arthroplasty using the Cox proportional hazards model. The predictors of revision surgery in the model include aTSA versus rTSA, indication for surgery, age, sex, race, urban versus rural residence, hospital length of stay zip code-based income quartile classification, and Elixhauser comorbidity readmission score.

RESULTS

Among 43,990 patients in this study, 1,141 (4.0%) underwent revision or implant removal over the 4-year study period. The median age was 71 years, and 57% of patients were female. Indications for the index surgery included primary osteoarthritis (75.2%), cuff tear (8.5%), acute fracture (7.0%), malunion/nonunion (1.4%), and other (7.8%). Among these indications for surgery, the risk of revision or removal was greatest in patients who underwent the primary procedure for malunion/nonunion (hazard ratio [HR] 2.39, 95% confidence interval [CI] 1.69 to 3.39) compared with the reference of primary osteoarthritis. Male patients who underwent aTSA were less likely to need revision surgery than male patients who underwent rTSA (HR: 0.59, 95% CI 0.49 to 0.71), and the opposite relationship was observed in female patients (HR: 1.41, 95% CI 1.18 to 1.69). Age, length of stay, and Elixhauser comorbidity score were predictive of revision surgery (P < 0.0001, P = 0.0005, P < 0.0001, respectively), whereas race, urban versus rural, and zip code-based income quartile were not.

DISCUSSION

aTSA and rTSA showed excellent 4-year survivorship of 96.0% in a large population-based sample. aTSA and rTSA survivorships were similar at the 4-year follow-up.

Revision Rates and Associated Risk Factors after Shoulder Arthroplasty

This study aims at answering the following questions (1) How high is the revision rate after osteoarthritis-, and rotator cuff-related compared to proximal humerus fracture (PHF)-related shoulder arthroplasty? (2) What are the associated risk factors for a revision after shoulder arthroplasty? Shoulder arthroplasty procedures occurring between 1 January 2009 and 31 December 2019 were identified from the Medicare database. First, revision rates for PHF patients and age- and sex-matched non-fracture patients, grouped into osteoarthritis-related and rotator cuff-related arthroplasty, were compared. Second, revision rates between total shoulder arthroplasty and hemiarthroplasty after PHF were compared. Semiparametric Cox regression was applied, incorporating 23 demographic, clinical, and socioeconomic covariates, to investigate risk factors for revision surgery. Between the considered time period from 2009 through 2019, a total number of 47,979 PHFs was identified. A shoulder arthroplasty procedure was performed in n = 2639 (5.5%, 95%CI: 4.8-6.1) of the cases. The five-year survivorship of the implant was 96.3 (95%CI: 93.8-97.9) after hemiarthroplasty and 96.1% (05%CI: 94.2-97.3) after total shoulder arthroplasty. To compare the revision rates, n = 14,775 patients with osteoarthritis and n = 4268 patients with rotator cuff arthropathy, who received a shoulder arthroplasty, served as a non-fracture control group. Patients receiving a rotator cuff-related arthroplasty were more likely to require a revision compared to patients treated for osteoarthritis (HR: 1.27, 95%CI: 1.04-1.44, p = 0.018). Identified significant risk factors for revision surgery after shoulder arthroplasty included age ≤ 75 years, male sex, and osteoporosis. High implant survival was found for hemiarthroplasty and total shoulder arthroplasty for the treatment of PHF in elderly patients. The risk of revision surgery was elevated in patients receiving a rotator cuff-related arthroplasty as well as in patients with osteoporosis, male patients and patients older than 75 years.

Treatment patterns of ABOS part II candidates: A decline of operative management among geriatric proximal humerus fractures over the decade (2010-2020)

BACKGROUND

The purpose of this study was to assess trends in ABOS part II candidate's operative management of geriatric (≥65 years) proximal humerus fractures over the 2010-2020 decade.

METHODS

This retrospective database cohort study utilized the American Board of Orthopaedic Surgery (ABOS) database for candidates taking Part II of their boards. Surgical coding was reviewed and the ICD10 data was correlated to the CPT code for shoulder arthroplasty or open reduction internal fixation. We investigated the number of proximal humerus fracture operative cases per year, the percent arthroplasty used per year, the stratification of percent arthroplasty per orthopaedic fellowship subspecialty and geographic region.

RESULTS

A total of 2,409 operative cases for proximal humerus fractures in patients 65 years of age and older were submitted by 1,420 ABOS candidates. There was a 37% reduction in operatively managed proximal humerus fractures among ABOS part II candidates between the first half of the decade (2010-2015, 263.2 +/- 13.4) and the second half of the decade (2016-2020, 166 +/- 31.2; p<.05). There also was a downward trend with a 53% reduction in percent treated with arthroplasty as compared to ORIF during those same windows (2010-2015, 34.4 +/-11.7) and (2016-2020, 16.2 +/- 6.4; p<.5). Partitioned by single fellowship training, Shoulder and Elbow (S&E) surgeons performed the highest percent arthroplasty at 25.2%, followed by Sports at 23.1% and the lowest percent arthroplasty was Trauma at 11.7%. The Southeast United States had the lowest percentage arthroplasty at 15.8% as compared to the Midwest (23.8%) and Northeast (25.8%).

CONCLUSION

Despite the rapid growth of both the elderly population and related geriatric proximal humerus fractures, ABOS candidates are treating less with surgery. There has been approximately a 37% decrease in the total number of operatively treated proximal humerus fractures between the first and second half 2010-2020 decade. When operative treatment is performed, there is a trend towards ORIF over an arthroplasty. Trauma fellowship trained surgeons are less likely to perform an arthroplasty as compared to other subspecialties. The Southeast region is least likely to perform an arthroplasty as compared to the Midwest or Northeast.

Reverse shoulder arthroplasty vs. hemiarthroplasty for the treatment of osteoporotic proximal humeral fractures in elderly patients: A systematic review and meta‑analysis update

The present meta-analysis was conducted to compare the safety and effectiveness of reverse shoulder arthroplasty (RSA) and hemiarthroplasty (HA) in the treatment of osteoporotic proximal humeral fractures in elderly patients. The Embase, Pubmed Central, Cumulative Index to Nursing and Allied Health Literature, ProQuest Dissertations and Theses, Cochrane Library and Chinese Biomedical databases were searched between January 2009 and January 2022 to identify relevant studies. According to the search strategy, a total of 210 associated studies were retrieved and 16 were finally included. Review Manager 5.4 software was used for the data analysis. This study indicated that patients in the RSA group had significantly improved treatment outcomes compared with patients in the HA group, as assessed by Constant-Murley Shoulder Outcome Score (95% CI, 1.69-3.76; P<0.001), American Shoulder and Elbow Surgeons score (95% CI, 11.81-24.88; P<0.001) and shoulder range of motion (ROM; 95% CI, 3.41-9.07; P<0.001). However, the HA group was superior to the RSA group in terms of the Oxford Shoulder score (95% CI, 2.89-11.11; P<0.001). There was no significant statistical difference between the two groups in terms of the Disabilities of the Arm, Shoulder and Hand score and complications. Overall, for the treatment of osteoporotic proximal humeral fractures in the elderly, the RSA group had improved postoperative ROM and functional scores compared with the HA group, without significant difference in the incidence of complications. However, HA remains a safe and reliable treatment option.

Accuracy of an Apparatus for Measuring Glenoid Baseplate Micromotion in Reverse Shoulder Arthroplasty

Reverse shoulder arthroplasty (RSA) is used to treat patients with cuff tear arthropathy. Loosening remains one of the principal modes of implant failure and the main complication leading to revision. Excess micromotion contributes to glenoid loosening. This study assessed the predictive accuracy of an experimental system designed to assess factors contributing to RSA glenoid baseplate micromotion. A half-fractional factorial experiment was designed to assess 4 factors: central element type (screw vs. peg), central element length (13.5 vs. 23.5 mm), anterior posterior peripheral screw type (locking vs. nonlocking) and cancellous bone density (10 vs. 25 pounds per cubic foot [pcf]). Four linear variable differential transducers (LVDTs) recorded micromotion from a stainless-steel disc surrounding a modified glenosphere. The displacements were used to interpolate micromotion at each of the respective peripheral screw positions. The mean absolute percentage error (MAPE) was used to determine the predictive accuracy and error range of the system. The MAPE for each condition ranged from 6.8% to 12.9% for an overall MAPE of (9.5&amp;#177;0.9)%. The system had an error range of 2.7 &amp;#181;m to 20.1 &amp;#181;m, which was lower than those reported by prior studies using optical systems. One of the eight conditions had micromotion that exceeded 150 &amp;#181;m. These findings support the use of displacement transducers, specifically LVDTs, as an accurate system for determining RSA baseplate micromotion in rigid polyurethane foam bone surrogates.

Stable glenoid component of reverse total shoulder arthroplasty at 2 years as measured with model-based radiostereometric analysis (RSA)

Background and purpose - Reverse total shoulder arthroplasty (TSA) is used for treating cuff arthropathy, displaced proximal humeral fractures (PHF), and in revision shoulder surgery, despite sparse evidence on long-term results. We assessed stability of the glenoid component in reverse TSA, using model-based RSA.Patients and methods - 20 patients (mean age 76 years, 17 female), operated on with reverse TSA at Oslo University Hospital, in 2015-2017 were included. Indications for surgeries were PHFs, malunion, cuff arthropathy, and chronic shoulder dislocation. RSA markers were placed in the scapular neck, the coracoid, and the acromion. RSA radiographs were conducted postoperatively, at 3 months, 1 year, and 2 years. RSA analysis was performed using RSAcore with Reversed Engineering (RE) modality, with clinical precision < 0.25 mm for all translations (x, y, z) and < 0.7° for rotations (x, z). Scapular "notching" was assessed in conventional radiographs.Results - 1 patient was excluded due to revision surgery. More than half of the patients displayed measurable migration at 2 years: 6 patients with linear translations below 1 mm and 8 patients who showed rotational migration. Except for one outlier, the measured rotations were below 2°. The migration pattern suggested implant stability at 2 years. 10 patients showed radiolographic signs of "notching", and the mean Oxford Shoulder Score (OSS) at 2 years was 29 points (15-36 points).Interpretation - Stability analysis of the glenoid component of reversed total shoulder arthroplasty using reversed engineering (RE) model-based RSA indicated component stability at 2 years.

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.

Ten-year follow-up of stemmed hemiarthroplasty for acute proximal humeral fractures

AIMS

There is no consensus on the treatment of proximal humeral fractures. Hemiarthroplasty has been widely used in patients when non-surgical treatment is not possible. There is, despite extensive use, limited information about the long-term outcome. Our primary aim was to report ten-year patient-reported outcome after hemiarthroplasty for acute proximal humeral fractures. The secondary aims were to report the cumulative revision rate and risk factors for an inferior patient-reported outcome.

METHODS

We obtained data on 1,371 hemiarthroplasties for acute proximal humeral fractures from the Danish Shoulder Arthroplasty Registry between 2006 and 2010. Of these, 549 patients (40%) were alive and available for follow-up. The Western Ontario Osteoarthritis of the Shoulder (WOOS) questionnaire was sent to all patients at nine to 14 years after primary surgery. Revision rates were calculated using the Kaplan-Meier method. Risk factors for an inferior WOOS score were analyzed using the linear regression model.

RESULTS

Mean age at surgery was 67 years (24 to 90) and 445 (81%) patients were female. A complete questionnaire was returned by 364 (66%) patients at a mean follow-up of 10.6 years (8.8 to 13.8). Mean WOOS score was 64 (4.3 to 100.0). There was no correlation between WOOS scores and age, sex, arthroplasty brand, or year of surgery. The 14-year cumulative revision rate was 5.7% (confidence interval 4.1 to 7.2). Patients aged younger than 55 years and patients aged between 55 to 74 years had 5.6-times (2.0 to 9.3) and 4.3-times (1.9 to 16.7) higher risk of revision than patients aged older than 75 years, respectively.

CONCLUSION

This is the largest long-term follow-up study of acute proximal humeral fractures treated with hemiarthroplasty. We found a low revision rate and an acceptable ten-year patient-reported outcome. The patient-reported outcome should be interpreted with caution as we have no information about the patients who died or did not return a complete WOOS score. The long-term outcome and revision rate suggest that hemiarthroplasty offers a valid alternative when non-surgical treatment is not possible. Cite this article: Bone Joint J 2021;103-B(6):1063-1069.