Quantifying success after first revision reverse total shoulder arthroplasty: the minimal clinically important difference, substantial clinical benefit, and patient acceptable symptomatic state

Pain relief survivorship: a comparison of Exactech Equinoxe anatomic and reverse total shoulder arthroplasty for primary osteoarthritis

BACKGROUND

Pain relief plays a major deterministic role when assessing postoperative patient satisfaction; however, whether anatomic total shoulder arthroplasty (aTSA) or reverse total shoulder arthroplasty (rTSA) provides the most durable pain relief has not been studied. The purpose of this study was to evaluate the durability of pain relief after aTSA compared with rTSA in patients undergoing surgery for rotator cuff-intact glenohumeral osteoarthritis (RCI-GHOA).

METHODS

A retrospective review of a multicenter shoulder arthroplasty database (Exactech Equinoxe) was performed. We included 1848 aTSAs and 1464 rTSAs performed for RCI-GHOA between 2007 and 2023. Pain after surgery was assessed postoperatively at 3 months, 6 months, and yearly thereafter. Average postoperative pain on a daily basis and pain at worst were compared between aTSA and rTSA up to 8 years postoperatively. Kaplan-Meier survivorship analysis for pain relief maintenance was performed to compare the maintenance of clinically relevant pain relief defined as pain scores that achieved the minimal clinically important difference (MCID), substantial clinical benefit (SCB), and patient acceptable symptomatic state (PASS). Maintenance of favorable patient satisfaction over time was also evaluated. Multivariable cox regression was performed to determine whether the type of prosthesis (aTSA vs. rTSA) was independently associated with pain recurrence.

RESULTS

Maintenance of achievement of the MCID and SCB for both daily pain and pain at worst as well as favorable patient satisfaction was similar between aTSAs and rTSAs. However, aTSA had longer maintenance of average daily pain below the PASS compared with rTSA (P = .024). This was confirmed on multivariable cox regression analysis, which found that rTSAs had a 34% greater likelihood of recurrence of postoperative average daily pain exceeding the PASS (visual analog scale score rating 1/10) compared with aTSAs.

CONCLUSION

Patients who undergo either aTSA or rTSA for RCI-GHOA and achieve initial pain relief postoperatively can expect to maintain their clinically relevant pain improvement at similar rates up to 8 years postoperatively. However, recurrence of low levels of daily pain was significantly higher after rTSA.

Anatomic total shoulder arthroplasty revised to reverse total shoulder arthroplasty: clinical and radiographic outcomes compared to primary reverse total shoulder arthroplasty

BACKGROUND

Reverse total shoulder arthroplasty (rTSA) has become the procedure of choice for a failed anatomic total shoulder arthroplasty (aTSA). Little data exist regarding outcomes; the few studies published to date have small numbers, short follow-up, and most do not have a control group or use first-generation implants. The purpose of this study is to compare the clinical and radiographic outcomes of failed aTSA revised to rTSA to primary rTSA.

METHODS

A prospective multicenter shoulder registry was used to conduct a retrospective review of patients who received a primary rTSA for osteoarthritis and rotator cuff disease and compare them to those who had an aTSA revised to a rTSA using the same implant between 2007 and 2021 with a minimum follow-up of 2 years. Cohorts were matched 3:1 (primary-to-revision) by age, gender, body mass index, and length of follow-up. Those who underwent revision for humeral fracture, infection, or an unknown reason were excluded. Preoperative and postoperative range of motion and patient-reported outcome measures (PROMs) were compared. Outcomes included rates of scapular notching, complications, revision, and patient satisfaction.

RESULTS

There were 88 aTSAs revised to rTSAs compared with 264 matched primary rTSAs. In both cohorts, the mean age was 68 years, 59% were female, and the mean follow-up was 56 months. The most common reason for revision was rotator cuff tearing (53%), followed by aseptic glenoid loosening (34%), instability (9%), aseptic humeral loosening (6%), and glenoid component dissociation (3%). At latest follow-up, patients in both groups had statistically significant improvements in all outcome scores, exceeding the minimal clinically important difference (MCID) and the substantial clinical benefit (SCB). The revision cohort had significantly less postoperative abduction (P < .001) and forward elevation (P = .001) compared with the primary rTSA cohort. All PROMs in the revision cohort were significantly worse than those in the primary rTSA cohort. Patient satisfaction rate in the revision cohort was significantly lower than the primary cohort (P < .001). Complication (P = .005) and revision rates (P = .013) were significantly higher in the revision cohort, whereas scapular notching was similar.

CONCLUSION

Patients undergoing revision of a failed aTSA to rTSA have worse clinical outcomes compared with those undergoing primary rTSA, including all PROMs, abduction, elevation, pain relief, and patient satisfaction, with higher complication and revision rates. Although patients in the revision group had significant improvements that exceeded the MCID and SCB, they do not achieve the same outcomes as patients who undergo primary rTSA.

Survivorship and clinical outcomes of reverse total shoulder arthroplasty in patients with large glenoid defects using the stilting technique and a baseplate with central ingrowth cage and peripheral locking screws

BACKGROUND

Stilting is a novel technique used in reverse shoulder arthroplasty (RSA) in patients with significant glenoid bone loss. This technique utilizes peripheral locking screws placed behind an unseated portion of the baseplate to transmit forces from the baseplate to the cortical surface of the glenoid, without the need for bone grafting. The stilted screw, once locked, provides a fixed angle point of support for this unseated aspect of a baseplate. The primary advantages of this technique are reduced cost compared to a custom implant and reduced operative time compared to bone grafting.

METHODS

We conducted a retrospective, nonrandomized, comparative cohort study of 41 patients who underwent primary RSA using the stilting technique with the Exactech Equinoxe Reverse System (Gainesville, FL, USA) at a single academic center from the years 2004 to 2021. Exclusion criteria included age under 18 or over 100 and oncologic or acute fracture RSA indications. Operative data was documented, including implant records, percent baseplate seating, and operative duration. Survivorship was compared among primary stilted RSA (n = 41), bone grafted RSA (n = 42), and non-stilted/non-bone grafted RSA (n = 1032) within our institutional shoulder arthroplasty database. A radiographic examination of baseplate failure was also conducted across the study groups. Postoperative functional outcomes were compared in a matched analysis involving patients with a minimum 2-year follow-up between stilted patients and a non-stilted/non-bone grafted control group for primary RSA.

RESULTS

All stilted RSA cases utilized metal augments and demonstrated a mean baseplate seating of 61% (range 45%-75%). For stilted RSAs, survivorship was 100% and 92.6% at 2 years and 5 years, compared to 98.3% and 94.6% for non-stilted/non-bone grafted and 96.3% and 79.5% for bone grafted RSAs (P = .042). At 5 years, the baseplate-related failure rates were greater in the stilted (7.4%) and the bone-grafted (9.3%) cohorts compared with the non-stilted/non-bone grafted cohort (1.1%, P < .001). The mean time to baseplate failure was 30 months for stilted RSA. Functional outcomes for primary RSA were statistically similar between stilted and non-stilted patients, including range of motion, Constant, American Shoulder and Elbow Surgeons, Simple Shoulder Test, University of California, Los Angeles, and Shoulder Pain and Disability Index scores.

CONCLUSION

The stilted RSA cohort exhibited noninferior revision and baseplate failure rates to that of bone grafted RSA. This suggests that stilting may be a viable technique for patients undergoing primary RSA with significant glenoid deformity.

Impact of tendon transfer on scapulothoracic and glenohumeral motion in children with brachial plexus birth injuries

BACKGROUND

Tendon transfers are often utilized to improve shoulder external rotation and abduction in children with brachial plexus birth injuries and are designed to improve glenohumeral (GH) joint motion. However, changes in scapulothoracic (ST) and GH joint function after tendon transfer are not well defined. The purpose of this study was to quantify changes in GH, ST, and humerothoracic (HT) joint function before and after tendon transfer, and we hypothesized that tendon transfers would reorient the arc of motion into more external rotation and abduction, but not increase GH motion.

METHODS

Motion analysis was performed in 15 children (ages 3-16) before and after transfer of teres major and/or latissimus dorsi. ST, GH, and HT joint angles were measured in a neutral, resting position and each of the modified Mallet positions. Joint angular displacements from the neutral position and the total arc of internal-external rotation for each joint were also calculated. Relevant joint angles, joint angular displacements, and internal-external rotation arcs were compared using multivariate analyses of variance with repeated measures and univariate posthoc analyses.

RESULTS

Glenohumeral and HT external rotation were significantly increased in all positions postoperatively. The arc of GH internal-external rotation was unchanged, but oriented in more external rotation after surgery. Only 6 patients gained active external rotation. Glenohumeral and HT internal rotation were significantly decreased after surgery, but ST internal rotation was significantly increased. Two patients had loss of midline function. In the abduction position, GH elevation joint angles were unchanged, but ST and HT elevation increased.

DISCUSSION

Only 4 patients gained active GH external rotation and maintained their internal rotation. Each of those patients underwent isolated tendon transfer without concomitant joint release. Seven patients maintained their preoperative internal rotation, which was attributed to increased ST internal rotation. The other half of patients lost internal rotation and gained external rotation through reorientation of the arc of rotation. Nine patients gained HT elevation, with 3 attributed to increased ST upward rotation, 5 attributed to a combination of increased ST upward rotation, and increased GH elevation, and 1 attributed to increased GH abduction contracture. These findings challenge the dogma that teres major/latissimus dorsi tendon transfers augment GH motion and highlight the importance of ST function for outcome determination.

Exactech Equinoxe anatomic vs. reverse total shoulder arthroplasty for primary osteoarthritis with an intact rotator cuff in patients with no glenoid deformity

BACKGROUND

Studies comparing anatomic and reverse total shoulder arthroplasty (aTSA, rTSA) for rotator cuff-intact glenohumeral osteoarthritis (RCI-GHOA) frequently fail to control for selection bias secondary to glenoid bone loss. Comparisons of similar patient populations without glenoid deformity may better evaluate potential differences in outcomes. The purpose of this study is to compare the outcomes of a matched cohort of aTSA and rTSA patients with RCI-GHOA and no glenoid bone loss.

METHODS

A retrospective review of primary aTSA/rTSA for RCI-GHOA with an A1 or B1 glenoid between 2007 and 2020 was performed. Matched cohorts were conceived based on age, sex, follow-up, Walch class, prior surgery, preoperative shoulder arthroplasty smart (SAS) score, preoperative forward elevation, and preoperative abduction. Range of motion, outcome scores, and rates of complications and reoperations were compared.

RESULTS

A total of 310 matched shoulders (155 aTSA, 155 rTSA) were evaluated at a mean 3.2 years follow-up. Postoperatively, aTSAs had more favorable abduction (146 ± 27° vs. 133 ± 26°, P < .001), internal rotation score (4.6 ± 1.3 vs. 4.1 ± 1.3, P = .004), external rotation (53 ± 15° vs. 43 ± 14°, P < .001), Constant score (73.6 ± 10.5 vs. 70.5 ± 12.8, P = .039), and SAS score (81.1 ± 9.7 vs. 77.2 ± 10.2, P = .002). However, when assessing improvement from preoperative state, only abduction remained significantly greater in the aTSA cohort (60° vs. 47°, P = .024). Patients undergoing aTSA achieved substantial clinical benefit at a higher rate for abduction (78% vs. 64%, P = .034) and external rotation (61% vs. 45%, P = .034). There was no difference in the incidence of complications (3.9% vs. 1.9%, P = .501) or revision surgery (3.2% vs. 0.6%, P = .214).

CONCLUSION

In patients with RCI-GHOA with no bone loss, treatment with rTSA demonstrated similar improvements compared to a matched aTSA cohort except for less improvement in abduction. rTSA does not appear to offer functional benefits over aTSA in this population. Longer term follow-up of this cohort needs to be considered to assess the longitudinal functional and revision rates of these patients.

Does Tranexamic Acid Improve Early Postoperative Shoulder Motion After Total Shoulder Arthroplasty?

PURPOSE

Although the hematologic benefits of tranexamic acid (TXA) have been thoroughly evaluated, an additional value demonstrated in knee arthroplasty and rotator cuff repair is improved early postoperative range of motion (ROM). This study aims to evaluate whether TXA given during total shoulder arthroplasty (TSA) confers improved early postoperative ROM or pain.

METHODS

We did retrospective review of 653 TSAs (223 anatomic TSA [aTSA] and 430 reverse TSA [rTSA]) performed in 596 patients at a single institution from 2007 to 2022. Intraoperative TXA use was implemented on a case-by-case basis starting in 2014 then became standard practice in 2016. Pre- to postoperative improvement in ROM was evaluated at 6 weeks, 3 months, 6 months, 1 year, and 2-years of follow-up. Mixed-effects models were used to evaluate whether administration of TXA intraoperatively improved ROM or pain at each follow-up time point.

RESULTS

TXA was administered to 26% (n = 58) of aTSAs and 43% (n = 179) of rTSAs. Patients with a history of hypertension received TXA at a higher rate for both aTSA ( P = 0.009) and rTSA ( P = 0.005). Intraoperative TXA was not associated with improved ROM or pain for aTSA or rTSA at any time point investigated. Average estimated intraoperative blood loss was markedly less in the TXA group for both aTSA [250 to 300 mL] ( P < 0.001) and rTSA [200 to 300 mL] ( P < 0.001) when compared with the non-TXA groups [300 to 400 mL for both].

CONCLUSION

Intraoperative TXA does not improve ROM or pain after TSA. However, intraoperative blood loss was reduced, further supporting the routine use of TXA to reduce hematologic complications and improve intraoperative visibility.

Anatomic Versus Reverse Total Shoulder Arthroplasty for Primary Osteoarthritis With an Intact Rotator Cuff: A Midterm Comparison of Early Top Performers

BACKGROUND

Several surgeons state that their best anatomic total shoulder arthroplasty (aTSA) outperforms their best reverse total shoulder arthroplasty (rTSA) when performed for rotator cuff-intact glenohumeral osteoarthritis. We identified the top-performing aTSAs and rTSAs at short-term follow-up and compared their clinical performance at midterm follow-up to validate this common claim.

METHODS

A retrospective review of a multicenter shoulder arthroplasty database was conducted. All shoulders undergoing primary aTSA or rTSA for rotator cuff-intact glenohumeral osteoarthritis between 2007 and 2020 were reviewed. Shoulders with a follow-up clinical visit between 2 and 3 years and a clinical follow-up of minimum 5 years were included. Two separate cohorts were identified: patients with a top 20% (1) American Shoulder and Elbow Surgeons (ASES) score and (2) Shoulder Arthroplasty Smart (SAS) score at 2 to 3 years of follow-up. Clinical outcomes including range of motion, outcome scores, and rates of complications and revision surgeries were compared at minimum 5-year follow-up.

RESULTS

The ASES score cohort comprised 185 aTSAs (mean age 67 years, 42% female) and 49 rTSAs (mean age 72 years, 45% female). The SAS score cohort comprised 145 aTSAs (mean age 67 years, 59% female) and 42 rTSAs (mean age 71 years, 57% female). Active external rotation (ER) was greater after aTSA at midterm follow-up in both ASES and SAS score cohorts; however, preoperative to postoperative improvement was equivalent. Postoperative ER and SAS scores were greater after aTSA in both cohorts ( P < 0.05); however, no other significant differences in any preoperative or postoperative clinical outcomes were present ( P > 0.05), and patients achieved the minimal clinically important difference and substantial clinical benefit at similar rates for all outcomes. No difference was found in the incidence of complications and revision surgeries between top-performing aTSAs and rTSAs.

CONCLUSION

Among top-performing shoulder arthroplasties at early follow-up, aTSA does not appear to outperform rTSA, except superior ER at midterm follow-up.

LEVEL OF EVIDENCE

Retrospective comparative cohort study, Level Ⅲ.

Acquired Acromion Compromise, Including Thinning and Fragmentation, Is Not Associated With Poor Outcomes After Reverse Shoulder Arthroplasty

BACKGROUND

Acquired acromial compromise, including thinning (less than 30% of the normal acromion) or fragmentation resulting from acromiohumeral impingement or previous acromioplasty, is a concern in reverse shoulder arthroplasty (RSA). This condition may lead to shoulder pain and difficulties in arm elevation because of acromial insufficiency fracture.

QUESTIONS/PURPOSES

(1) Do patients with acromial compromise (thinning less than 30% of normal acromion or fragmentation) have worse functional outcome scores, ROM, and strength after RSA compared with patients without acromial compromise? (2) Are patients with acromial compromise at a higher risk of complications such as acromial insufficiency fracture after RSA? (3) Do patients who develop acromial insufficiency fracture have predisposing associated factors and worse clinical outcomes?

METHODS

Between January 1, 2016, and December 31, 2020, we treated 398 patients with RSA, and all patients were considered potentially eligible for this study. Our clinic is part of the orthopaedic department within a tertiary general hospital, serving patients from across the country. Among them, 49% (197 of 398) of patients were excluded for the following reasons: 8% (31 of 398) because of proximal humerus fracture, 5% (19 of 398) because of osteonecrosis, 9% (35 of 398) because of previous infective arthritis, 5% (18 of 398) because of a deformed shoulder, 4% (14 of 398) because of poor general condition after surgery, 3% (12 of 398) because of death, and another 17% (68 of 398) were lost before the minimum study follow-up, leaving 51% (201 of 398) for analysis. A preoperative acromial compromise was defined as follows: (1) thinning of the acromion (< 3 mm), which means a thickness of less than 30% of the normal acromion thickness (8 to 9 mm), and (2) acromial fragmentation. Acromial thickness was measured using a CT scan. The middle portion of the anterolateral acromion, situated lateral to the distal end of the clavicle, was crosschecked using the axial view. Measurements were subsequently performed from both coronal and sagittal views. In all, 29 patients with acromion compromise and 172 without acromion compromise met the inclusion and exclusion criteria. There was no differential loss to follow-up before 2 years between patients with and without acromial compromise in this study (36% [16 of 45] versus 23% [52 of 224]; p = 0.12). We matched patients using propensity score, pairing them in a 1:3 ratio based on gender, age, bone mineral density, diagnosis, previous rotator cuff repair surgery, subscapularis repair or latissimus dorsi transfer performed during surgery, the type of prosthesis used, and follow-up duration. Twenty-three patients with acromial compromise (acromion compromised group) and 69 patients without acromial compromise (normal control group) were matched; the mean ± SD duration of follow-up was 40 ± 22 months in those with acromial compromise and 43 ± 19 months the in normal control group. Pre- and postoperative functional outcome scores, ROM, and shoulder strength were compared. Shoulder scaption refers to lifting the arm in the scapular plane, and scaption strength was measured by applying upward force with the arm at 90° while seated, pushing it as far as possible and measured using a handheld myometer. Complications, including acromial insufficiency fracture, scapular notching, dislocation, periprosthetic infection, and overall risk of complication, were analyzed. Acromial insufficiency fracture was diagnosed based on clinical and radiological findings. Clinically, sudden pain and tenderness at the acromion along with reduced shoulder elevation raised acromial insufficiency fracture suspicion. Radiologically, acromion tilt on plain radiograph or fracture line on coronal CT view confirmed diagnosis of acromial insufficiency fracture.

RESULTS

Comparing both groups, patients with a compromised acromion had no difference in American Shoulder and Elbow Surgeons scores (60 ± 12 versus 64 ± 12; mean difference -4 [95% CI -11 to 2]; p = 0.16), Constant scores (48 ± 10 versus 54 ± 12; mean difference -6 [95% CI -13 to 0]; p = 0.06), forward flexion degree (125 ± 24 versus 130 ± 21; mean difference -5 [95% CI -16 to 6]; p = 0.36), and scaption strength (5 ± 3 versus 6 ± 3; mean difference -1 [95% CI -3 to 0]; p = 0.13). Having acromial compromise was not associated with increased risk of overall complications (30% [7 of 23] versus 19% [13 of 69], relative risk 2 [95% CI 1 to 4]; p = 0.26). However, the only complication that was higher in the acromial compromised group was infection (13% [3 of 23] versus 0% [0 of 69], relative risk not available; p = 0.01). Only the lateralized glenoid prosthesis demonstrated negative association with the acromial insufficiency fracture occurrence; no other factors showed an association. The use of lateralized glenoid prostheses was not observed in patients with acromial insufficiency fracture (0% [0 of 7] acromial insufficiency fracture versus 39% [33 of 85] no acromial insufficiency fracture, relative risk 0 [95% CI 0]; p = 0.047).

CONCLUSION

In patients with acquired acromial compromise-such as thinning or fragmented acromion because of advanced cuff tear arthropathy or previous acromioplasty-primary RSA resulted in no different functional outcome score, ROM, shoulder strength, and overall complications compared with patients without acromial compromise. Our findings suggest that a thin or fragmented acromion may not necessarily be exclusion criteria for RSA, potentially aiding surgeons in their decision-making process when treating these patients. However, one of the major complications, postoperative infection, is more frequently observed in patients with acquired acromial compromise. Pre- and postoperative caution would be necessary to prevent and detect infection even when short-term outcomes are favorable in this study. Further studies with large cohorts and long-term follow-up durations are needed.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Stratification of the minimal clinically important difference, substantial clinical benefit, and patient acceptable symptomatic state after total shoulder arthroplasty by implant type, preoperative diagnosis, and sex

BACKGROUND

Clinical significance, as opposed to statistical significance, has increasingly been utilized to evaluate outcomes after total shoulder arthroplasty (TSA). The purpose of this study was to identify thresholds of the minimal clinically important difference (MCID), substantial clinical benefit (SCB), and patient acceptable symptomatic state (PASS) for TSA outcome metrics and determine if these thresholds are influenced by prosthesis type (anatomic or reverse TSA), sex, or preoperative diagnosis.

METHODS

A prospectively collected international multicenter database inclusive of 38 surgeons was queried for patients receiving a primary aTSA or rTSA between 2003 and 2021. Prospectively, outcome metrics including ASES, shoulder function score (SFS), SST, UCLA, Constant, VAS Pain, shoulder arthroplasty smart (SAS) score, forward flexion, abduction, external rotation, and internal rotation was recorded preoperatively and at each follow-up. A patient satisfaction question was administered at each follow-up. Anchor-based MCID, SCB, and PASS were calculated as defined previously overall and according to implant type, preoperative diagnosis, and sex. The percentage of patients achieving thresholds was also quantified.

RESULTS

A total of 5851 total shoulder arthroplasties (TSAs) including aTSA (n = 2236) and rTSA (n = 3615) were included in the study cohort. The following were identified as MCID thresholds for the overall (aTSA + rTSA irrespective of diagnosis or sex) cohort: VAS Pain (-1.5), SFS (1.2), SST (2.1), Constant (7.2), ASES (13.9), UCLA (8.2), SPADI (-21.5), and SAS (7.3), Abduction (13°), Forward elevation (16°), External rotation (4°), Internal rotation score (0.2). SCB thresholds for the overall cohort were: VAS Pain (-3.3), SFS (2.9), SST 3.8), Constant (18.9), ASES (33.1), UCLA (12.3), SPADI (-44.7), and SAS (18.2), Abduction (30°), Forward elevation (31°), External rotation (12°), Internal rotation score (0.9). PASS thresholds for the overall cohort were: VAS Pain (0.8), SFS (7.3), SST (9.2), Constant (64.2), ASES (79.5), UCLA (29.5), SPADI (24.7), and SAS (72.5), Abduction (104°), Forward elevation (130°), External rotation (30°), Internal rotation score (3.2). MCID, SCB, and PASS thresholds varied depending on preoperative diagnosis and sex.

CONCLUSION

MCID, SCB, and PASS thresholds vary depending on implant type, preoperative diagnosis, and sex. A comprehensive understanding of these differences as well as identification of clinically relevant thresholds for legacy and novel metrics is essential to assist surgeons in evaluating their patient's outcomes, interpreting the literature, and counseling their patients preoperatively regarding expectations for improvement. Given that PASS thresholds are fragile and vary greatly depending on cohort variability, caution should be exercised in conflating them across different studies.

Converting to reverse shoulder arthroplasty from primary anatomic shoulder arthroplasty and fracture hemiarthroplasty: a radiographic and clinical outcome analysis at 8-years

INTRODUCTION

Revision shoulder arthroplasty can be challenging. One of the main considerations for surgeons is the type of implant that was placed in the initial surgery. Anatomic shoulder arthroplasty (ASA) is used for cases of osteoarthritis as well as for fractures of the humeral head. Hemiarthroplasty can be used for complex proximal humerus fractures. The purpose of this study is to determine whether there is a difference in clinical and radiographic outcomes between patients that failed primary fracture hemiarthroplasty (FHA), or ASA for osteoarthritis and then required reoperation with a conversion to reverse shoulder arthroplasty (RSA).

METHODS

Patients with failed anatomic shoulder replacement, who had undergone conversion to RSA, were enrolled after a mean follow-up of 107 (85-157) months. Two different groups, one with failed ASA implanted for osteoarthritis and one with failed FHA, were created. At follow-up patients were assessed with standard radiographs and clinical outcome scores.

RESULTS

Twenty-nine patients (f = 17, m = 12; 51%) suffered from a failed ASA (Group A), while the remaining 28 patients (f = 21, m = 74; 49%) had been revised due to a failed FHA (Group B). Patients of Group B had a poorer Constant score (Group A: 60 vs. Group B: 46; p = 0.02). Abduction (Group A: 115° vs. Group B: 89°; p = 0.02) was worse after conversion of a failed FHA to RSA in comparison to conversions of failed ASA. The mean bone loss of the lateral metaphysis was higher in patients with failed FHA (Group A: 5 mm vs. Group B: 20 mm; p = 0.0).

CONCLUSION

The initial indication for anatomic shoulder arthroplasty influences the clinical and radiological outcome after conversion to RSA. Conversion of failed FHA to RSA is related to an increased metaphyseal bone loss, decreased range of motion and poorer clinical outcomes when compared to conversions of failed ASA implanted for osteoarthritis.

LEVEL OF EVIDENCE

III Retrospective Cohort Comparison Study.

Quantifying success after first revision reverse total shoulder arthroplasty: the minimal and substantial clinically important percentage of maximal possible improvement

BACKGROUND

When patients require reoperation after primary shoulder arthroplasty, revision reverse total shoulder arthroplasty (rTSA) is most commonly performed. However, defining clinically important improvement in these patients is challenging because benchmarks have not been previously defined. Furthermore, although the minimal clinically important difference and substantial clinical benefit are commonly used to assess clinically relevant success, these metrics are limited by ceiling effects that may cause inaccurate estimates of patient success. Our purpose was to define the minimal and substantial clinically important percentage of maximal possible improvement (MCI-%MPI and SCI-%MPI) for commonly used pain and functional outcome scores after revision rTSA and to quantify the proportion of patients achieving clinically relevant success.

METHODS

This retrospective cohort study used a prospectively collected single-institution database of patients who underwent first revision rTSA between August 2015 and December 2019. Patients with a diagnosis of periprosthetic fracture or infection were excluded. Outcome scores included the American Shoulder and Elbow Surgeons (ASES), raw and normalized Constant, Shoulder Pain and Disability Index (SPADI), Simple Shoulder Test (SST), and University of California, Los Angeles (UCLA) scores. We used an anchor-based method to calculate the MCI-%MPI and SCI-%MPI. In addition, we calculated the MCI-%MPI using a distribution-based method for historical comparison. The proportions of patients achieving each threshold were assessed. The influence of sex, type of primary shoulder arthroplasty, and reason for revision rTSA were also assessed by calculating cohort-specific thresholds.

RESULTS

Ninety-three revision rTSAs with minimum 2-year follow-up were evaluated. The mean age of the patients was 67 years; 56% were female, and the average follow-up was 54 months. Revision rTSA was performed most commonly for failed anatomic TSA (n = 47), followed by hemiarthroplasty (n = 21), rTSA (n = 15), and humeral head resurfacing (n = 10). The indication for revision rTSA was most commonly glenoid loosening (n = 24), followed by rotator cuff failure (n = 23) and subluxation and unexplained pain (n = 11 for both). The anchor-based MCI-%MPI thresholds (% of patients achieving) were ASES = 33% (49%), raw Constant = 23% (64%), normalized Constant = 30% (61%), UCLA = 51% (53%), SST = 26% (68%), and SPADI = 29% (58%). The anchor-based SCI-%MPI thresholds (% of patients achieving) were ASES = 55% (31%), raw Constant = 41% (27%), normalized Constant = 52% (22%), UCLA = 66% (37%), SST = 74% (25%), and SPADI = 49% (34%).

CONCLUSIONS

This study is the first to establish thresholds for the MCI-%MPI and SCI-%MPI at minimum 2 years after revision rTSA, providing physicians an evidence-based method to assess patient outcomes postoperatively.

Two-Stage Exchange Arthroplasty for Periprosthetic Reverse Shoulder Arthroplasty Infection Provides Comparable Functional Outcomes to Primary Reverse Shoulder Arthroplasty

This study aimed to compare functional outcomes after two-stage revision reverse shoulder arthroplasty (RSA) for periprosthetic joint infection (PJI) with the results of primary RSA. Patients affected by PJI and treated by means of two-stage revision RSA were 1:1 matched with a group of patients who were treated electively with RSA without developing any complications. Out of 1477 RSAs performed between 2009 and 2021, 16 patients developed a PJI. Each matched cohort comprised 16 patients (3 females, 13 males). The mean age was 69.13 ± 5.43 years old in the PJI group and 70.28 ± 5.04 (p = 0.543) in the matched cohort. The mean follow-up was 41.23 ± 26.9 months in the PJI group and 28.5 ± 20.2 (p = 0.142) in the matched group. Only one patient showed recurrent PJI five years after revision RSA. Comparison between the PJI patients and matched patients did not show any significant differences at the latest follow-up, nor for subjective shoulder value (SSV) (p = 0.101) or Constant score (p = 0.134). Two-stage exchange RSA for PJI allows for appropriate control of the disease and good functional outcomes. Comparison with an age- and sex-matched cohort of uninfected patients showed no significant differences, thus confirming the idea that revision surgeries may lead to satisfactory functional outcomes, as expected after primary surgery.