Factors affecting risk of recurrence with periprosthetic infection in shoulder arthroplasty

BACKGROUND

The goal of treating periprosthetic infection, besides its eradication, is to avoid recurrence. The purpose of this study was to evaluate the impact of increasing Infection Severity (IS) score (based on the 2018 International Consensus Meeting on Orthopedic Infections statement), single-stage revision, and pathogenicity of the infective organism on the risk of infection recurrence.

METHODS

A database of 790 revisions performed by a single surgeon from 2004-2020 was reviewed for patients with minimum 2-year follow-up and ≥1 positive culture finding and/or pathology result from the revision surgical procedure. In total, 157 cases performed in 144 patients met the inclusion criteria. These cases were then categorized by infection probability (IS score) according to the 2018 consensus statement. Of 157 cases, 46 (29%) were classified as definitely or probably infected; 25 (16%), possibly infected; and 86 (55%), unlikely to be infected. Additionally, patients were grouped by single-stage surgery and pathogenicity of the infective organism.

RESULTS

A recurrence in this study was classified as the growth of the same organism in any patient requiring revision surgery. The 86 cases in the group with unlikely infection showed a recurrence rate of 2.3%. The 25 cases in the group with possible infection showed a recurrence rate of 12%. The 46 cases in the group with definite or probable infection showed a recurrence rate of 17.4%. Patients in the definite/probable infection group had a higher rate of recurrence than those in the groups with possible infection and unlikely infection (P = .009). The IS score was higher in the recurrence group than the non-recurrence group (7.5 ± 4.3 vs. 3.9 ± 3.4, P < .001). Overall, patients who underwent 1-stage revision had a 5.0% recurrence rate, but among the 34 patients with an infection classification of definite or probable who underwent 1-stage revision, the recurrence rate was 5.9%. Cases of highly virulent methicillin-resistant Staphylococcus aureus also showed a recurrence rate of 30.8% compared with 4.0% and 5.9% for Cutibacterium acnes and coagulase-negative staphylococci, respectively (P = .005).

CONCLUSION

Recurrent infection after treatment of a periprosthetic infection is associated with increasing severity scores, as defined in the 2018 consensus statement, and more aggressive microorganisms. However, a single-stage surgical procedure, even in patients with higher IS scores, did not impart a significantly increased risk of recurrence.

Glenoid-based reference system to differentiate shoulder pathologies on plain radiographs

BACKGROUND

Shoulder radiographs are used for evaluation and the planning of treatment of various pathologies. Making a diagnosis of these pathologies on plain radiographs occurs by recognizing the relationship of the humeral head on the registry of the glenoid. Quantification of these changes in registry does not currently exist. We hypothesize that a geometric relationship of the humeral head and the glenoid exists that is defined on an anteroposterior Grashey view radiograph by the relationship of the best-fit circle of the humeral head relative to the best-fit circle of the glenoid such that relative measurements will define the normal shoulder and the pathologic shoulder.

METHODS

One hundred fifty-six shoulders were included: 53 normal shoulders, 51 with primary glenohumeral osteoarthritis (GHOA), and 52 with cuff tear arthropathy (CTA). Humeral head best-fit circle was used to define the circle of the humeral head (cHH). A glenoid best-fit circle (cG) was defined by the following rules: (1) best fit of the glenoid articular surface and (2) was limited by the acromion such that either (a) it reaches maximal interaction with the inferior surface of the acromion or (b) the perimeter of the circle is at the lateralmost point of the acromion. The relationship between cHH and cG is defined by measurement of cHH in horizontal and vertical planes relative to the glenoid circle reference. The horizontal displacement angle (HDA) measures the horizontal position of cHH relative to cG, representing the degree of medialization toward the glenoid. The vertical displacement angle (VDA) measures the vertical position of cHH relative to cG, representing the degree of superiorization toward the acromion. Angles were compared by diagnosis and sex.

RESULTS

The mean HDA was 61.0° (95% confidence interval [CI] 60.3°-61.7°) in normal shoulders, 79.9° (95% CI 76.9°-82.9°) in GHOA, and 63.4° (95% CI 61.7°-65.1°) in CTA (P < .001). The mean VDA was 43.1° (95% CI 42.2°-44.0°) in normal shoulders, 40.9° (95% CI 39.9°-42.0°) in GHOA, and 59.7° (95% CI 57.6°-61.7°) in CTA (P < .001). Interobserver reliability was 0.991 (95% CI 0.94-1.0) and intraobserver reliability was 0.998 (95% CI 0.99-1.0). The geometric relationship of cHH to the glenoid circle reference was plotted for each group.

CONCLUSION

A geometric relationship exists of the humeral head in reference to the glenoid circle. Together, the HDA and the VDA distinguish between a normal shoulder and those with GHOA or CTA. This suggests that this novel methodology may provide a preoperative planning tool that is easily accessible.

Do preoperative scapular fractures affect long-term outcomes after reverse shoulder arthroplasty?

BACKGROUND

Postoperative scapular stress fractures (SSFs) are a formidable problem after reverse shoulder arthroplasty (RSA). Less is known about patients who have these fractures preoperatively. The primary aim of this study was to examine postoperative satisfaction in patients undergoing primary RSA who have preoperative SSF and compared to a matched cohort without preoperative fracture. The secondary aim was to examine the differences in patient-reported outcomes between and within study cohorts.

METHODS

A retrospective chart review of primary RSAs performed by a single surgeon from 2000 to 2020 was conducted. Patients diagnosed with cuff tear arthropathy (CTA), massive cuff tear (MCT), or rheumatoid arthritis (RA) were included. Five hundred twenty-five shoulders met inclusion criteria. Fractures identified on preoperative computed tomography scans were divided into 3 groups: (1) os acromiale, (2) multifragments (MFs), and (3) Levy types. Seventy-two shoulders had an occurrence of SSF. The remaining 453 shoulders were separated into a nonfractured cohort. American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) and visual analog scale (VAS) scores were compared pre- and postoperatively in the total fracture group and the nonfractured group cohort. The multifragment subgroup was also compared to the pooled Os/Levy subgroup.

RESULTS

The total incidence of SSF in all shoulders was 13.7%. There was a difference in satisfaction scores at all time points between the nonfracture (7.9 ± 2.8) and total fracture group (5.4 ± 3.6, P < .001, at last visit). There was also a greater ASES total score in the nonfractured group vs the total fracture group at the final visit (69.4 ± 23.4 and 62.1 ± 24.2; P = .02). The MF group had worse ASES functional or VAS functional scores than the Os/Levy group at all time points: at 1 year, ASES function: MF 24.2 ± 14.5 and Os/Levy 30.7 ± 14.2 (P = .045); at 2 years, ASES function: MF 21.4 ± 14.4 and Os/Levy 35.5 ± 10.6 (P < .001); and at last follow-up, VAS function: MF 4.8 ± 2.8 and Os/Levy 6.4 ± 3.2 (P = .023).

DISCUSSION

Scapular fractures were proportionally most common in patients diagnosed with CTA (16.3%) compared with a 9.2% and 8.6% incidence in patients diagnosed with MCT and RA, respectively. Patients with preoperative SSF still see an improvement in ASES scores after RSA but do have lower satisfaction scores compared with the nonfractured cohort. The multifragment fracture group has lower functional and satisfaction scores at all postoperative time points compared with both the nonfracture and the Os/Levy fracture group.

Optimizing Muscle-Tendon Lengths in Reverse Total Shoulder Arthroplasty: Evaluation of Surgical and Implant-Design-Related Parameters

BACKGROUND

Optimizing the function of muscles that cross the glenohumeral articulation in reverse total shoulder arthroplasty (RTSA) is controversial. The current study used a geometric model of the shoulder to systematically examine surgical placement and implant-design parameters to determine which RTSA configuration most closely reproduces native muscle-tendon lengths of the deltoid and rotator cuff.

METHODS

A geometric model of the glenohumeral joint was developed and adjusted to represent small, medium, and large shoulders. Muscle-tendon lengths were assessed for the anterior deltoid, middle deltoid, posterior deltoid, and supraspinatus from 0 to 90° of scaption; for the subscapularis from 0° to 60° of internal rotation (IR) and 0° to 60° of scaption; for the infraspinatus from 0° to 60° of external rotation (ER) and 0° to 60° of scaption; and for the teres minor from 0° to 60° of ER at 90° of scaption. RTSA designs were virtually implanted using the following parameters: (1) surgical placement with a centered or inferior glenosphere position and a humeral offset of 0, 5, or 10 mm relative to the anatomic neck plane, (2) implant design involving a glenosphere size of 30, 36, or 42 mm, glenosphere lateralization of 0, 5, or 10 mm, and humeral neck-shaft angle of 135°, 145°, or 155°. Thus, 486 RTSA-shoulder size combinations were analyzed. Linear regression assessed the strength of association between parameters and the change in each muscle-tendon length from the native length.

RESULTS

The configuration that most closely restored anatomic muscle-tendon lengths in a small shoulder was a 30-mm glenosphere with a centered position, 5 mm of glenoid lateralization, 0 mm of humeral offset, and a 135° neck-shaft angle. For a medium shoulder, the corresponding combination was 36 mm, centered, 5 mm, 0 mm, and 135°. For a large shoulder, it was 30 mm, centered, 10 mm, 0 mm, and 135°. The most important implant-design parameter associated with restoration of native muscle-tendon lengths was the neck-shaft angle, with a 135° neck-shaft angle being favored (β = 0.568 to 0.657, p < 0.001). The most important surgical parameter associated with restoration of native muscle-tendon lengths was humeral offset, with a humeral socket placed at the anatomic neck plane being favored (β = 0.441 to 0.535, p < 0.001).

CONCLUSIONS

A combination of a smaller, lateralized glenosphere, a humeral socket placed at the anatomic neck plane, and an anatomic 135° neck-shaft angle best restored native deltoid and rotator cuff muscle-tendon lengths in RTSA.

CLINICAL RELEVANCE

This study of surgical and implant factors in RTSA highlighted optimal configurations for restoration of native muscle-tendon lengths of the deltoid and rotator cuff, which has direct implications for surgical technique and implant selection. Additionally, it demonstrated the most influential surgical and implant factors with respect to muscle-tendon lengths, which can be used to aid intraoperative decision-making.

Common Factors in Shoulder and Hip Arthroplasty Implant Failures: A Historical Review

In this era of subspecialty care in orthopedics, iterations of implant design can occur in a silo which then precludes gaining knowledge from failures of implant design that may have occurred in different subspecialties. This literature review describes the history of failures in hip and shoulder arthroplasties with the purpose of identifying similar factors that led to previous implant failures. A review of the literature was performed by two reviewers assessing articles that described failed hip and shoulder arthroplasty systems over time. We identified and analyzed 53 implant failures-23 in hip arthroplasty and 30 in shoulder arthroplasty. These failures were categorized as material, mechanical, and technical. In hip arthroplasty, 48% were material, 39% mechanical, and 13% technical failures. In shoulder arthroplasty, the distribution was 10% material, 70% mechanical, and 20% technical failures. The distribution of these failures highlights similar and sometimes repeated failure mechanisms between subspecialties. This accentuates the importance of a collaborative approach to improve future arthroplasty designs.

Revision reverse shoulder arthroplasty for the management of baseplate failure: an analysis of 676 revision reverse shoulder arthroplasty procedures

BACKGROUND

Baseplate failure in reverse shoulder arthroplasty (RSA) is a rare but potentially catastrophic complication owing to poor patient outcomes and significant glenoid bone loss. The purpose of this study was to report on the prevalence, causes, and outcomes of revision RSA (rRSA) for baseplate failure or loosening.

METHODS

A retrospective review of our institutional database was performed to identify all patients treated for a failed RSA from 2006 to 2021 who required revision to another RSA (rRSA) performed by a single surgeon. A total of 676 failed RSA procedures were identified, and further analysis identified 46 patients (6.8%) who underwent rRSA for baseplate failure with a confirmed loose baseplate at the time of rRSA. The primary outcome was repeated failure of the reimplanted baseplate following rRSA. The mode of failure associated with baseplate failure was stratified into 1 of 3 groups: aseptic, septic, or traumatic. Twenty-four patients underwent primary revision, and 22 had undergone >1 previous arthroplasty prior to undergoing re-revision. Five patients underwent previous rRSA for baseplate failure performed by an outside surgeon. The criteria for secondary outcome analysis of final American Shoulder and Elbow Surgeons score, Simple Shoulder Test score, and range of motion were met by 32 patients and 23 patients at 1- and 2-year follow-up, respectively.

RESULTS

Three patients (6.5%) had repeated baseplate failure requiring re-revision; 2 had baseplate failure at <1 year with associated periprosthetic infections and underwent conversion to hemiarthroplasty. The third patient experienced traumatic failure at 10 years and underwent successful rRSA. The mean American Shoulder and Elbow Surgeons scores at 1 and 2 years were 62.3 and 61.7, respectively. There was no significant difference in outcomes based on mode of baseplate failure (P = .232) or total arthroplasty burden (P = .305) at 1 year. There were 13 total complications in 11 patients, 5 of which required reoperation for reasons other than baseplate failure.

CONCLUSION

In this study, rRSA for baseplate failure constituted 6.8% of all revisions performed over a period of 15 years. Re-revision for recurrent baseplate failure was required in 3 of 46 patients (6.5%). Complications and reoperation rates were higher than those for primary RSA but outcomes were comparable for revision of failed anatomic shoulder arthroplasty.

How to avoid baseplate failure: the effect of compression and reverse shoulder arthroplasty baseplate design on implant stability

BACKGROUND

Failure to achieve fixation of the glenoid baseplate will lead to clinical failure. The fixation of the baseplate to the scapula must be able to withstand sufficient shear forces to allow bony ingrowth. The importance of compression to neutralize the forces at the baseplate-bone interface has been assumed to be critical in limiting excessive micromotion. The purpose of this study is to determine the effect of compression on implant stability with different baseplate designs.

METHODS

Various baseplate designs (1-piece monolithic central screw [1P], 2-piece locking central screw [2PL], and 2-piece nonlocking center screw [2PNL]) were investigated at 3 different compressive forces (high [810 N], medium [640 N], and low [530 N]). Synthetic bone cylinders were instrumented, and peripheral screws were used in all models. The combination of 1 locking and 3 nonlocking peripheral screw fixation was selected as worst-case scenario. Dynamic testing protocol followed the ASTM F2028-17 standard. The baseplate micromotion at high compression was compared to low compression. Additionally, the baseplate micromotion for each design was compared at baseline (first 50 cycles) and at 10,000 cycles for the 3 different compressive forces where motion above 150 μm was defined as failure.

RESULTS

Baseplate micromotion was found to negatively correlate with compression (rpb = -0.83, P < .0001). At baseline, all baseplate designs were considered stable, regardless of compression. With high compression, average micromotion at the glenoid baseplate-bone interface remained below the 150-μm threshold for all baseplate designs at 10,000 cycles (1P: 50 ± 10 μm; 2PL: 78 ± 32 μm; 2PNL: 79 ± 8 μm; P = .060). With medium compression, average micromotion at 10,000 cycles for all 3 designs remained below the 150-μm threshold (1P: 88 ± 22 μm; 2PL: 132 ± 26 μm; 2PNL: 107 ± 39 μm). The 2PL design had the highest amount of micromotion (P = .013). With low compression, both 2-piece designs had an average micromotion above the 150-μm threshold whereas the 1-piece design did not (1P: 133 ± 35 μm; 2PL: 183 ± 21 μm; 2PNL: 166 ± 39 μm). The 2PL design had significantly higher micromotion when compared to 1P design (P = .041).

DISCUSSION

The stability of a central screw baseplate correlates with the amount of compression obtained and is affected by implant design. For the same amount of compression, more micromotion is observed in a 2-piece design than a 1-piece design.

Maximizing Implant Stability in the Face of Glenoid Bone Stock Deficiency

As the incidence of shoulder arthroplasty continues to rise, encountering significant glenoid bone loss in the primary and revision setting is becoming a common occurrence. To effectively treat these difficult scenarios, surgeons must understand the common patterns of glenoid bone loss and be aware of the various techniques available for treatment. Understanding bone loss requires careful pre-operative evaluation with appropriate imaging and pre-operative planning software. Treatment algorithms consist of primary anatomic and reverse arthroplasty as well as the use of allograft or autograft bone grafting, augmented glenoid components, specialized surgical techniques, or custom implant designs. Ultimately, good outcomes are able to be obtained with various techniques when applied to the appropriate clinical situation.

Impact of reverse shoulder arthroplasty design and patient shoulder size on moment arms and muscle fiber lengths in shoulder abductors

BACKGROUND

Reverse shoulder arthroplasty (RSA) increases the moment arm of the deltoid; however, there is limited knowledge on the accompanying changes in muscle architecture that play a role in muscle force production. The purpose of this study was to use a geometric shoulder model to evaluate the anterior deltoid, middle deltoid, and supraspinatus regarding (1) the differences in moment arms and muscle-tendon lengths in small, medium, and large native shoulders and (2) the impact of 3 RSA designs on moment arms, muscle fiber lengths, and force-length (F-L) curves.

METHODS

A geometric model of the native glenohumeral joint was developed, validated, and adjusted to represent small, medium, and large shoulders. Moment arms, muscle-tendon lengths, and normalized muscle fiber lengths were assessed for the supraspinatus, anterior deltoid, and middle deltoid from 0° to 90° of abduction. RSA designs were modeled and virtually implanted, including a lateralized glenosphere with an inlay 135° humeral component (lateral glenoid-medial humerus [LGMH]), a medialized glenosphere with an onlay 145° humeral component (medial glenoid-lateral humerus [MGLH]), and a medialized glenosphere with an inlay 155° humeral component (medial glenoid-medial humerus [MGMH]). Descriptive statistics were used to compare moment arms and normalized muscle fiber lengths.

RESULTS

As shoulder size increased, the moment arms and muscle-tendon lengths for the anterior deltoid, middle deltoid, and supraspinatus increased. All RSA designs achieved greater moment arms for the anterior and middle deltoid, with the MGLH design achieving the largest increase. The resting normalized muscle fiber length of the anterior and middle deltoid was substantially increased in the MGLH (1.29) and MGMH (1.24) designs, shifting the operating ranges of these muscles to the descending portions of their F-L curves, whereas the LGMH design maintained a resting deltoid fiber length (1.14) and operating range similar to the native shoulder. All RSA designs demonstrated a decrease in the native supraspinatus moment arm in early abduction, with the largest decrease in the MGLH design (-59%) and minimal decrease in the LGMH design (-14%). The supraspinatus operated on the ascending limb of its F-L curve in the native shoulder and remained on this portion of the F-L curve for all RSA designs.

CONCLUSION

Although the MGLH design maximizes the abduction moment arm for the anterior and middle deltoid, overlengthening of the muscle may compromise deltoid muscle force production by forcing the muscle to operate on the descending portion of its F-L curve. In contrast, the LGMH design increases the abduction moment arm for the anterior and middle deltoid more modestly while allowing the muscle to operate near the plateau of its F-L curve and maximizing its force-producing potential.

What factors can reduce the need of repeat revision for humeral loosening in revision total elbow arthroplasty?

BACKGROUND

This study aims to determine re-revision rate in a cohort who underwent revision total elbow arthroplasty (rTEA) for humeral loosening (HL) and identify factors contributing to re-revision. We hypothesize that proportional increases in the stem and flange lengths will stabilize the bone-implant interface significantly more than disproportional increases in stem or flange length alone. Additionally, we hypothesize that the indication for the index arthroplasty will impact the need for repeat revision for HL. The secondary objective was to describe the functional outcomes, complications, and radiographic loosening after rTEA.

METHODS

We retrospectively reviewed 181 rTEAs performed from 2000-2021. Forty rTEAs for HL performed on 40 elbows that either required a subsequent revision for humeral loosening (10 rTEAs) or had a minimum of two years of clinical or radiographic follow-up were included. One hundred thirty-one cases were excluded. Patients were grouped based on stem and flange length to determine the re-revision rate. Patients were divided based on re-revision status into a single revision group and re-revision group. The stem to flange lengths (S/F) ratio was calculated for each surgery. Mean clinical and radiographic follow-up was 71 months (range, 18-221 months; 3-221 months, respectively).

RESULTS

Rheumatoid arthritis (RA) was statistically significant in predicting re-revision TEA for HL (p value = 0.024). The overall re-revision rate for HL was 25% at average 4.2 years (range, 1-19) from revision procedure. There was a significant increase in stem and flange lengths from index procedure to revision, on average by 70±47mm (p<0.001) and 28±39mm (p<0.001), respectively. In cases of re-revisions (n=10), four patients went into excisional procedure, and in the remaining six cases the size of re-revision implant increased on average by 37±40mm for stem and 73±70mm for flange (p=0.075 and p=0.046). Furthermore, average flange in these 6 cases was 7 times shorter than average stem (S/F=6.7±2.2). This was significantly different from cases were not re-revised (p=0.03; S/F=4.6±1.8 and 4.2±2, respectively). Mean range of motion was 16° (range: 0°-90°; SD: 20°) to 119° (range: 0°-160°; SD: 39°) at final follow-up. Complications included ulnar neuropathy (38%), radial neuropathy (10%), infection (14%), ulnar loosening (14%), and fracture (14%). None of the elbows were considered radiographically loose at final follow-up.

CONCLUSION

We show that the primary diagnosis of RA and a humeral stem with a relatively short flange relative to the stem length significantly contribute to re-revision of TEA. The use of an implant where flange can be extended beyond one fourth of the stem length may increase implant longevity.

Humeral Loosening in Reverse Shoulder Arthroplasty: An Analysis of 2,000 Cases

INTRODUCTION

Humeral loosening is a rare complication in reverse shoulder arthroplasty (RSA) representing approximately 1% of total complications. The purpose of this study is to identify patients who underwent RSA and were revised due to loosening of the humeral component, identify patients who are at increased risk, and report on their surgical outcomes.

MATERIALS AND METHODS

A retrospective review of all patients who received a primary RSA or revision RSA (rRSA) by a single surgeon from 2002-2021 identified a total of 1,591 primary RSA and 751 rRSA procedures. These procedures were then organized based on indication for surgery. Further analysis was performed to identify RSAs that were subsequently revised due to aseptic loosening of the humeral component. A total of 41 surgeries met inclusion criteria for the study, which was any RSA or rRSA that was revised due to loosening of the humeral component. Exclusion criteria was revision for a reason other than humeral loosening, neurogenic arthritis, or revision for loosening that was not originally implanted by the senior author (9 surgeries). Ultimately, 32 surgeries met criteria for further analysis. These 32 surgeries were organized by indication for preceding RSA or rRSA and were assessed for an association between indication for RSA/rRSA and eventual revision for humeral loosening. Additionally, these procedures were compared to a "control cohort" of procedures that were not revised and that had minimum 2-years follow-up. To assess outcomes for these patients, pre- and postoperative SST, ASES, and ranges of motion were compared. Twenty procedures had sufficient data for outcomes analysis and were followed for an average of 54 months (range: 24-132 months).

RESULTS

In primary RSAs, procedures performed for fracture or fracture sequelae were associated with revision for humeral-sided loosening (p = 0.009). In rRSAs, procedures performed for failed hemiarthroplasty for CTA were associated with re-revision for humeral-sided loosening (p = 0.009). Nine percent of patients revised for humeral loosening required re-revision for recurrent humeral loosening. Analysis of patients with 2-year clinical follow-up for humeral-sided loosening showed improvement in ASES pain (p = 0.014), ASES function (p = 0.042), and total ASES scores (p = 0.007).

CONCLUSION

Humeral loosening is rare in RSA. In our cohort, 0.7% of primary RSAs performed and 2.8% of rRSAs performed were eventually revised for humeral loosening. Revisions of RSA for humeral loosening yield modest clinical improvements. Re-revision for humeral loosening was 6.3% of patients in our cohort.

Three-Dimensional Scapular Border Method for Glenoid Version Measurements

Variations among methods to measure glenoid version have created uncertainty regarding which method provides the most consistent measurements of morphology. Greater deformity may also make accurate depiction of the native morphology more challenging. This study examined 4 current methods (Friedman, corrected Friedman, Ganapathi-Iannotti, and Matsumura) and an experimental scapular border-derived coordinate system method, to compare measurement inconsistencies between methods and reference systems and assess the impact of glenoid deformity on measured glenoid version.

Methods

Three-dimensional scapulae were created from computed tomography (CT) scans of 74 shoulders that had undergone arthroplasty (28 A2, 22 B2, 10 B3, and 14 C glenoids) and 34 shoulders that had not undergone arthroplasty. Glenoid version measurements were made in Mimics using the 4 methods. For the experimental method, scapulae were reconstructed, and 3 orthogonal global coordinate planes (GCPs) were derived from the medial and lateral borders. Version was measured as the angle between the sagittal reference plane and an anterior-posterior glenoid vector. The intraclass correlation coefficient (ICC) was calculated for the Friedman and corrected Friedman methods. Inconsistencies were assessed for all methods using the interquartile range, mean and standard deviation, and repeated-measures analysis of variance. Concordance correlation coefficients (CCCs) were calculated to assess agreement among the methods.

Results

Scapular plane-based methods (experimental, Friedman, and corrected Friedman) yielded an average version between -10° and -12°, with average measurement differences among these methods of <2°. Vault methods (Ganapathi-Iannotti and Matsumura) overestimated or underestimated version by an average of 5° to 7° compared with scapular plane-based methods, and showed significant differences of >12° when compared with each other. Scapular plane-based methods maintained consistency with increasing deformity.

Conclusions

The other methods of version measurement using the scapular planes as the reference were highly comparable with the corrected Friedman method. However, when the reference plane was the glenoid vault, version measurements were inconsistent with scapular plane-based methods, which is attributed to differences in the reference systems. In surgical planning, the coordinate system utilized will impact version measurements, which can result in variations in the planned surgical solutions. Additionally, as glenoid deformity increases, this variation resulting from the utilization of different coordinate systems is magnified.

Outcomes of Femoral Head Allograft for the Management of Glenoid Bone Defects in Revision Reverse Shoulder Arthroplasty: A Case-Controlled Study

BACKGROUND

Revision shoulder arthroplasty often requires management of glenoid bone defects. Options include using allograft, harvesting iliac crest autograft, or using augmented metal components. The purpose of this study is to report outcomes of revision shoulder arthroplasty requiring management of glenoid bone defects with femoral head allograft in a large cohort of patients using a single reverse shoulder implant system and compare them to a matched cohort based on the indication for surgery. Outcomes of patients who had successful glenoid reconstruction were compared to those that required a re-revision, and to a control group that was revised without the need for bone graft.

METHODS

This was a retrospective review of data collected from 2009 to 2018. There were 36 patients in the bone graft group and 52 in the control group. All patients underwent revision to a reverse shoulder arthroplasty to manage a failed total shoulder arthroplasty (n = 29 and 11), hemiarthroplasty (n = 1 and 24), or reverse shoulder arthroplasty (n = 6 and 17). All patients had a minimum of 2 years of clinical follow-up. The primary endpoint was survival of baseplate fixation. Secondary outcomes included range of motion and functional outcome scores. Patients that had recurrent baseplate failure and were re-revised were compared to patients with bone graft that did not require additional surgery, and to patients who were revised without the need for bone graft. Patients who required revisions for reasons other than recurrent baseplate failure were also recorded.

RESULTS

Five of 36 (14%) patients had recurrent baseplate failure. Mean time to failure was 12 months. Three of 5 had successful re-implantation of another baseplate. Two of 5 were revised to a hemi arthroplasty after failure of their revisions. Preoperative ASES scores were 31 in the grafted patients that did not require re-revision, 39 in the grafted patients that required re-revision, and 33 in the control group. Final ASES scores were 64, 36, and 56, respectively. One patient required revision surgery not related to baseplate failure. There were no baseplate failures in the control group.

CONCLUSION

The use of femoral head allograft to manage glenoid bone defects in the revision setting produces predictable improvement in functional outcomes that is not inferior to those in patients revised without bone graft. However, there is a 14% rate of baseplate failure.

My Reverse Has Failed: Top Five Complications and How to Manage Them

Reverse total shoulder arthroplasty implantation has increased dramatically over the past 4 decades since it was first introduced in France in 1985. It has greatly improved the ability to treat patients with cuff tear arthropathy, proximal humeral fractures, and osteoarthritis with severe bone loss. However, with the increased implementation of reverse total shoulder arthroplasty, there has been a corresponding rise in complications. Five of the most common complications following reverse total shoulder arthroplasty are instability, scapular fractures, periprosthetic humeral fractures, glenoid baseplate loosening, and infection.

Does improved external rotation following reverse shoulder arthroplasty impact clinical outcomes in patients with rotator cuff pathology and external rotation less than 0°?

BACKGROUND

The purpose of this study was to (1) evaluate whether improved external rotation (ER) in patients with preoperative ER <0° impacts their clinical outcomes following reverse shoulder arthroplasty (RSA) for rotator cuff (RC) pathology and (2) describe the differences in preoperative factors and postoperative outcomes in this patient population. Our hypothesis was that clinical outcomes would not be affected by improvement in ER using a lateralized glenosphere design.

METHODS

We retrospectively reviewed 55 patients with preoperative ER <0° who underwent primary RSA for RC pathology with lateralized glenosphere. Pre- and postoperative physician-reported ER was blindly measured using a videographic review of patients externally rotating their arm at the side. Patients were evaluated using 5 different patient-reported outcome score thresholds, measured at 12 months postoperatively: (1) minimal clinically important difference (MCID) for American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) scores (ie, ≥20-point increase); (2) MCID for Simple Shoulder Test (SST) scores (≥2.4-point increase); (3) visual analog scale (VAS) for pain score >0; (4) mean ASES score (≥75); and (5) mean SST score (≥6.8), each of which was used to stratify the patients into 2 groups-greater than or equal to vs. less than the threshold. This resulted in 5 different evaluations comparing the 2 groups for any difference in postoperative ER or preoperative factors, including Hamada and Goutallier scores.

RESULTS

Regardless of the measured outcome, there was no difference in either postoperative physician- or patient-reported ER between patients who achieved scores higher or lower than the thresholds. Both Hamada and Goutallier score distributions were not different between groups across all the evaluated outcomes. Patients who achieved the MCID for ASES had worse preoperative VAS pain (7 vs. 4, P = .011) and SST (1 vs. 3, P = .020) scores. Across all outcome thresholds, except MCID for SST, pain reduction (ΔVAS) was significantly more pronounced in patients exceeding the thresholds. Improved forward flexion rather than ER was observed in those who achieved the ASES (160° vs. 80°, P = .020) and SST MCIDs (150° vs. 90°, P = .037). Finally, patients who exceeded the thresholds experienced higher satisfaction rates.

CONCLUSION

Improvement in ER does not appear to impact patient-reported outcome measures, including ASES and SST in patients with preoperative ER <0° undergoing RSA with a lateralized glenosphere. Patients with more severe pain and worse function at baseline experience less postoperative pain and clinically significant improvement in their reported outcomes.

Improved mechanical fixation of an all-polyethylene glenoid reduces postoperative radiolucent lines

BACKGROUND

The rationale for advances in implant design is to improve performance in comparison to their predecessors. The purpose of this study was to compare a newer, self-pressurizing peripheral peg glenoid to a traditional polyethylene pegged glenoid through biomechanical evaluation and a retrospective radiographic and clinical review.

METHODS

Three testing conditions (uncemented, partially cemented, and fully cemented) were chosen to assess the 2 component designs in a foam block model. The number of hammer hits to seat the component, amount of time to seat the component, and resistance-to-seat were collected. The implants were then cyclically loaded following ASTM F2028-17 testing standard. Clinically, postoperative radiographs of patients with a self-pressurized glenoid component (n = 225 patients) and traditional glenoid component (n = 206 patients) were evaluated for radiolucent lines and glenoid seating at various timepoints. Clinical outcomes (American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form, Simple Shoulder Test, and visual analog scale pain scores) and complications were recorded. The presence of radiolucent lines at the bone-cement interface was evaluated using the Modified Franklin Grade and the Lazarus grade.

RESULTS

The self-pressurizing glenoid design required significantly more hammer hits than traditional glenoid designs in all groups tested (P < .029). Moreover, the self-pressurizing design had significantly more resistance-to-seat than traditional components in both the uncemented and partially cemented group (P < .002). No difference in resistance-to-seat was found between designs in the fully cemented group. The uncemented and partially cemented groups did not survive the full 50,000 cycles; however the self-pressurizing design had significantly less motion than the traditional design (P < .001). No differences between component designs were found in the fully cemented group at 50,000 cycles. The self-pressurizing glenoid component had 0.005% radiographic radiolucent lines, and the traditional glenoid component had 45% radiographic radiolucent lines, with 38% of the radiolucencies in the traditional glenoid component group being defined as grade E. There were no progressive radiolucencies, differences in clinical outcomes, or complications at 2 years postoperatively.

CONCLUSION

In the fully cemented condition, the 2 component designs had comparable performance; however, the differences in designs could be better observed in the uncemented group. The self-pressurizing all-polyethylene design studied has superior biomechanical stability. Clinically, the improved stability of the glenoid component correlated with a reduction of radiolucent lines and will likely lead to a reduction in glenoid component loosening.

Do preoperative factors and implant design features influence humeral stem extraction efforts?

BACKGROUND

Variations in humeral component designs in hemiarthroplasty and anatomic total shoulder arthroplasty cases can impact the degree of difficulty during a revision surgery that necessitates the removal of the humeral stem. However, no metric exists to define stem extraction effort nor to identify associated factors that contribute to extraction difficulty. The purpose of this study is to describe a method to quantify stem extraction difficulty and to define features that will impact the effort during stem removal.

METHODS

This was a retrospective review of 58 patients undergoing revision of hemiarthroplasty or anatomic total shoulder arthroplasty requiring stem extraction. Each included patient had existing preoperative radiographic examination, an intraoperative video of the stem removal process, and explants available for analysis by 3 surgeons. The following factors were assessed for the impact on extraction difficulty: (1) preoperative features such as cement use, fill of proximal humerus, and stem design features; (2) intraoperative data on extraction time and bone removal; and (3) postoperative findings related to extraction artifacts (EAs). A scoring system was established to distinguish easy (Easy group) and difficult (Difficult group) stem removal cases and further used to identify the features that may affect intraoperative difficulty of stem removal.

RESULTS

The Difficult group accounted for 26% (15/58) of the study population with an 18-minute average stem extraction time, average EA count of 69, and 35 mm of bone removed. The Easy group accounted for 74% (43/58) of patients, with a 4-minute average extraction time, average EA count of 23, and 10 mm of bone removed. Logistic regression model was able to correctly classify 82% of the cases, explaining 26.7% of the variance in humeral stem removal with cement and proximal coating variables. The likelihood of cemented stem removal being difficult is 5 times greater compared to an uncemented stem, and having proximal coating doubles the likelihood of a difficult stem removal compared to cases with no coating.

CONCLUSIONS

Quantifying stem extraction difficulty is possible with intraoperative video as well as explant analysis. Preoperative features of the fixation type and specific features of stem design such as proximal coating will impact difficulty of stem extraction.

Acromial fractures following reverse shoulder arthroplasty: the role of the acromial morphology and a comparison of clinical outcomes

BACKGROUND

The purpose was to evaluate the relationship between acromial morphology and the location of acromial fractures following reverse shoulder arthroplasty and determine whether fracture location and displacement impact clinical outcomes.

METHODS

We performed a multicenter retrospective review of reverse shoulder arthroplasties complicated by acromial fractures. Radiographs were compared to determine the differences in acromial morphology, as well as fracture orientation and pattern, between patients with Levy type I (n = 17) and Levy type II (n = 25) fractures. Patients with a minimum of 2 years' follow-up were selected to examine the association between clinical outcomes and fracture location and displacement. Twenty-two patients were stratified based on whether they achieved the minimal clinically important difference (MCID) in the American Shoulder and Elbow Surgeons score (20 points). The groups were then compared regarding fracture location and displacement using measurements such as the acromiohumeral distance.

RESULTS

The Levy type I group had a higher acromial slope than the Levy type II group (127° vs. 117°, P < .001). Levy type I fractures had a transverse pattern occurring in the coronal plane, whereas Levy type II fractures had an oblique pattern occurring in the sagittal plane (P < .001). At final follow-up, 12 of 22 patients (55%) achieved the MCID. Those who did not achieve the MCID had more displaced fractures including a lower acromiohumeral distance (8 mm vs. 20 mm, P = .007). There was no difference in the distribution of Levy type I and type II fractures based on the MCID cutoff (P = .093).

CONCLUSION

An increased acromial slope is associated with transverse fractures in the Levy I region, whereas a lower acromial slope is associated with oblique fractures in the Levy II region. Overall, 55% of patients achieved the MCID at mid-term follow-up. The outcomes of those who did not achieve the MCID became worse postoperatively, and this was associated with increased fracture displacement.

Identifying areas of screw fixation in glenoids with severe bone loss in shoulder arthroplasty

BACKGROUND

Severe glenoid bone loss (SGBL) poses significant technical challenges. Adequate fixation of glenoid implants may require the use of alternative screw placement. Although bone volumes for the spine and lateral pillars have previously been defined, insufficient evidence exists regarding the distribution of screw placement for fixation in such regions for cases with SGBL. The purpose of this study is to evaluate the variability of screw placement. We hypothesize that determining this variability and establishing common patterns of glenoid bone loss will allow for recommendations for preoperative planning, and implant design and selection.

METHODS

An internal registry of 2 high-volume shoulder and elbow surgeons was queried, and 65 three-dimensional scapulae models exhibiting SGBL were identified. A fellowship-trained shoulder and elbow surgeon simulated the placement of two 3.5 mm × 30 mm screws, one in the scapular spine (CS) bone volume and one in the inferior column (IS) bone volume. Three orthogonal reference planes were created using anatomic reference points: the scapula trigonum, estimated glenoid center, and inferior pole. Screw positions were mapped, and deviations from the reference planes were calculated. Mutual positions of the IS to CS were also computed. Intraobserver reliability was assessed using 10 randomly selected samples. Median and 25th and 75th percentiles were reported for screw orientation distributions. Means and standard deviations were reported for screw head positions.

RESULTS

We demonstrated excellent intraobserver reliability (intraclass correlation coefficients, 0.90-0.98). Fifty percent of CS were oriented 10° ± 5° of retroversion from the scapula plane, with 5° ± 5° of inclination. For IS, 50% were positioned 0° ± 4° from the scapula plane, with -33° ± 7° of inclination. The relationship of the IS with the CS was medial and posterior in 49% of cases, lateral and posterior in 45%, and lateral and anterior in 6% of cases. On average, the distance between the CS and IS heads was 25 mm ± 4 mm.

DISCUSSION

For SGBL, adequate fixation of glenoid implants can be achieved by placing screws in the spine and lateral columns, with excellent reproducibility. Future implant designs should accommodate CS positioned -16° to -5° from the scapula plane, with 0° to 12° of inclination, and IS positioned -6° to 4° from the scapula plane, with -40° to -25° of inclination. Moreover, mutual screw positions suggested bone loss distributions anteriorly and inferiorly. Future implant designs should consider the potential benefits of augmentation to accommodate interscrew distances of 21-29 mm and anatomic locations of the IS relative to the CS.

Avoiding Glenoid Baseplate Fixation Failure by Altering Surgical Technique for Varying Bone Densities

Glenoid baseplate failure is one of the causes of revision and poor outcomes in reverse shoulder arthroplasty (RSA). The objective of this study was to determine whether alterations in surgical technique can improve time-zero fixation of the baseplate in varying bone densities. A secondary objective was to identify whether preoperative radiographic glenoid sclerosis width was associated with the implementation of these techniques.

A Weaving Rip-Stop Technique Leads to a Significantly Increased Load to Failure and Reduction in Suture-Tendon Cut-Through in a Biomechanical Model of Rotator Cuff Repair

Purpose

To present an alternative arthroscopic rip-stop technique with a single suture tape weaved through the tendon from anterior to posterior and to biomechanically test its strength against a control technique consisting of a single-row repair with simple sutures.

Methods

This was a controlled biomechanical study. Dissection and harvesting of the supraspinatus muscle-tendon unit were performed along the cable in 9 matched-pair cadaveric shoulders. Samples were divided into 2 groups: simple suture repair only (SSR) and simple suture repair with rip-stop (SSPR). Biomechanical testing was performed with an initial preload, followed by cyclic loading and then ramp to failure. Peak-to-peak displacement, stiffness (in newtons per millimeter), load at failure (in newtons), and failure mechanism were recorded. Data were compared using the paired-sample t test.

Results

The average peak-to-peak displacement for SSR samples was not significantly different from that of SSPR samples (P = .96). Similarly, elongation in the SSR and SSPR groups was not significantly different (P = .82). Stiffness was significantly different between the SSR and SSPR groups (P = .0054): SSR samples were less stiff than SSPR samples. Moreover, SSR samples failed at significantly lower forces than did SSPR samples (P = .028). A larger percentage of failures occurred due to tendon cut-through among SSR samples versus suture breakage among SSPR samples.

Conclusions

An alternative rip-stop technique is presented in this biomechanical model that may assist surgeons to better deal with difficult rotator cuff repairs. Weaving a suture tape as a rip-stop can increase stiffness, achieve higher failure loads when compared with simple suture repair with no rip-stop, and reduce tendon cut-through.

Clinical Relevance

This study provides insight into a variation of rip-stop stitch techniques that may help solve the clinical problem of failure occurring at the suture-tendon interface, specifically tendon cut-through.

Comparing patient-reported outcome measures and physical examination for internal rotation in patients undergoing reverse shoulder arthroplasty: does surgery alter patients' perception of function?

BACKGROUND

The purpose of this study was to evaluate how patients treated with reverse shoulder arthroplasty (RSA) achieve internal rotation (IR) using video assessment and to compare this to patient-reported outcome measures (PROMs).

METHODS

We reviewed 215 preoperative and 657 postoperative videos (3-78 months) for 215 patients who underwent primary RSA, performing IR using the modified vertebral level method. Their functional motion pattern was then grouped into 3 types: type I, could not reach behind their back; type II, able to reach to at least waist level, with assistance; and type III, able to reach to a minimum of waist level in an uninterrupted fashion. Patients completed functional questions (put on a coat, wash back, tuck in a shirt, and manage toileting) and a diagram of perceived IR. Patients' functional motion types were compared to PROM answers. Pre- and postoperative scores were also compared to assess the effect of surgery on patients' perception of IR function.

RESULTS

Patients undergoing RSA will achieve IR in 3 distinct motion patterns. Analysis of self-reported IR indicated statistically significant difference between the 3 functional types of IR (P < .001). Patient-perceived IR was not significantly different between the 3 studied IR functional types (P = .076) in the analysis of preoperative measures but was significantly different in the postoperative setting (P < .001).

CONCLUSION

Patients attempt IR in 3 distinct functional motion patterns. The improvement of IR after RSA is measured better by patient questionnaires than by physical examination.

Influence of preoperative factors on timing for bilateral shoulder arthroplasty

INTRODUCTION

In bilateral shoulder arthroplasty patients, it is unclear what features are responsible for the timing of their contralateral shoulder arthroplasty. This study hypothesized that patient factors (age, gender, and hand dominance), disease factors (diagnosis and radiographic severity of contralateral shoulder), and surgical factors (type of arthroplasty) impact the timing to contralateral surgery.

METHODS

A retrospective review of 332 patients treated with bilateral anatomic (TSA) or reverse (RSA) shoulder arthroplasty (172 TSA/TSA, 107 RSA/RSA, or 53 TSA/RSA) were divided into groups depending on the interval timing between arthroplasty surgeries: group 1, n = 142 (≤1 year); group 2, n = 62 (1-2 years); and group 3, n = 128 (≥2 years). Preoperative factors were analyzed to determine associations between different time groups, including age, gender, hand dominance, diagnosis, radiographic severity of contralateral shoulder, and type of surgery. Bilateral diagnoses included 211 osteoarthritis (OA), 36 cuff tear arthropathy (CTA), 13 inflammatory arthritis, 12 massive cuff tears without OA, and 4 avascular necrosis.

RESULTS

OA patients had their contralateral shoulder arthroplasty sooner than CTA patients (P = .035). OA patients with arthritic changes on contralateral radiographs before the first arthroplasty had their contralateral arthroplasty sooner than those without contralateral radiographs (P < .0001). Patients who had TSA first had their contralateral arthroplasty sooner than patients who had RSA first (P = .037).

DISCUSSION

This study confirmed our hypothesis identifying preoperative variables associated with different time intervals between arthroplasties. The preoperative factors associated with the highest likelihood of having contralateral shoulder arthroplasty within 1 year included OA, radiographic bilateral shoulder disease, and TSA for the first surgery.

The subscapularis-sparing windowed anterior technique for total shoulder arthroplasty

BACKGROUND

Traditionally, total shoulder arthroplasty (TSA) involves detaching the subscapularis tendon through either tenotomy or lesser tuberosity osteotomy. A subscapularis-sparing approach avoids detachment but may make re-creation of the anatomy more difficult because of limited exposure. The primary aim of this study was to evaluate the ability to re-create the proximal humeral geometry and assess for osteophyte removal with this technique. The secondary aim was to assess for complications or an inability to complete the procedure with this technique.

METHODS

We performed a retrospective review of a consecutive series of 47 patients (100% with osteoarthritis; 59% Walch type A and 41% Walch type B; 50% male and 50% female patients; and average body mass index, 28.21 ± 4.6) who underwent the subscapularis-sparing windowed anterior technique for TSA. The ability to reconstruct the proximal humeral geometry and remove the inferior osteophytes was assessed by 2 independent observers using the center-of-rotation difference (ΔCOR) between the native and prosthetic humeral heads. The ability to complete the procedure was recorded, and a chart review was performed to assess for complications.

RESULTS

The procedure was successfully completed in 44 of the 47 patients. Radiographic review demonstrated an average ΔCOR of 2.28 mm (range, 0.2-6.05 mm; intraclass correlation coefficient, 0.971), below the previously reported acceptable ΔCOR of 3 mm. The ΔCOR was >3 mm in 31.8% of patients (14 of 44; 8 Walch type A and 6 Walch type B; 9 male and 5 female patients). There was no difference in ΔCOR based on Walch type (P = .824). Male patients on average showed a higher ΔCOR (2.62 mm) than female patients (1.94 mm) (P = .099) and more commonly had a ΔCOR > 3 mm (P = .195). Body mass index was not significantly correlated with ΔCOR (r = 0.077, P = .619). For all cases in which the ΔCOR was >3 mm, the prosthetic humeral head was undersized. Osteophytes were successfully removed in 75% of cases (33 of 44) and had no effect on average ΔCOR (P = .468). No revisions or mechanical failures in the early postoperative period were identified in the treatment group of 44 patients (range, 3-15 months). In the group with unsuccessful treatment, there was 1 case of infection treated with 1-stage revision reverse TSA.

DISCUSSION

The subscapularis-sparing windowed anterior technique is an effective approach to TSA that allows for early unrestricted motion. Over 90% of cases can be completed using this technique. Radiographic analysis demonstrated that this approach can be used successfully without compromising anatomic reconstruction of the proximal humerus. Further study is necessary to identify patient factors that would favor a traditional deltopectoral approach and to assess the functional outcomes of this technique.

A cohort comparison of humeral implant designs in reverse shoulder arthroplasty: does implant design lead to lower rates of complications and revision?

INTRODUCTION

The purpose of this study was to evaluate the outcomes, revisions, and complications between a first-generation cemented modular humeral implant and a second-generation monolithic, primarily uncemented humeral implant in reverse total shoulder arthroplasty with 135° neck-shaft angle and varying degrees of metallic glenosphere offsets.

METHODS

We retrospectively evaluated patients undergoing reverse total shoulder arthroplasty from 2004 to 2014 with a first-generation cemented modular humeral implant (400 patients) or second-generation monolithic humeral stem (231 patients), who had at minimum 2-year clinical and radiographic follow-up.

RESULTS

Both groups of patients had similar improvement of clinical outcomes (American Shoulder and Elbow Surgeons +30 points vs. +34 points, respectively) with improvements in all planes of motion (forward flexion +70° vs. +75°, abduction +61° vs. +71°, external rotation +23° vs. +22°, and internal rotation +1.6 vs. +1.5 level improvement, respectively). The incidence of humeral loosening for the cemented group was 3.6%, whereas in the uncemented group it was 0.4% (P = .01). A total of 28 shoulders treated with the cementing technique (4.0%) and 6 patients treated with the press-fit technique (1.5%) were revised (P = .028). The rate of postoperative acromial fractures within the first year was 3.4% in the cemented group and 1.8% in the uncemented group (P = .177).

CONCLUSIONS

Both the first-generation cemented modular humeral stem implant and the second-generation monolithic humeral stem implant had equivalent clinical outcomes. In addition, with the monolithic stem primarily using press-fit fixation, there was a significant reduction in the incidence of radiographic loosening and the need for revision compared with a cemented stem.

The effect of glenoid bone loss and rotator cuff status in failed anatomic shoulder arthroplasty after revision to reverse shoulder arthroplasty

HYPOTHESIS

We evaluated outcomes and the risk of re-revision in patients with a failed anatomic total shoulder arthroplasty (TSA) revised to a reverse shoulder arthroplasty (RSA) based on rotator cuff deficiency and glenoid bone loss.

METHODS

From 2004 to 2017, 123 patients with failed TSAs underwent revision to RSAs with minimum 2-year follow-up. Preoperative radiographs were evaluated to determine whether the glenoid component was fixed or loose. The rotator cuff was assessed intraoperatively and as intact or deficient. Patient outcomes including shoulder motion and American Shoulder and Elbow Surgeons (ASES) scores were obtained preoperatively and postoperatively. Patient outcomes were compared based on glenoid fixation and rotator cuff status. There were 18 TSAs revised to RSAs that underwent subsequent revision.

RESULTS

The mean preoperative ASES score was 31 (95% confidence interval [CI], 29-33) with no difference in preoperative ASES scores based on glenoid status (P = .412) or rotator cuff status (P = .89). No difference in postoperative ASES score was found based on glenoid component status or rotator cuff status. However, improvement in the ASES score was greater with an intact rotator cuff (mean postoperative score, 67 [95% CI, 57-76] vs. 55 [95% CI, 50-60]; P = .025). The overall re-revision rate was 11.4%, with a mean time to re-revision of 22 months (range, 0-89 months). The odds ratio was 1.786 for subsequent revision in patients with glenoid loosening compared with those without loose glenoids on preoperative radiographs.

CONCLUSION

There was an overall improvement in patient outcomes for failed TSAs revised to RSAs; however, patients with an intact cuff had a greater improvement in ASES scores.

Machine Learning Can Predict Level of Improvement in Shoulder Arthroplasty

The ability to accurately predict postoperative outcomes is of considerable interest in the field of orthopaedic surgery. Machine learning has been used as a form of predictive modeling in multiple health-care settings. The purpose of the current study was to determine whether machine learning algorithms using preoperative data can predict improvement in American Shoulder and Elbow Surgeons (ASES) scores for patients with glenohumeral osteoarthritis (OA) at a minimum of 2 years after shoulder arthroplasty.

The Basic Shoulder Arthroplasty: Simple Shoulder Replacement for the Generalist

Shoulder arthroplasty was first introduced through the developments of Dr. Charles Neer and over the past decade has seen several advancements. Improved recognition and training have heightened the awareness of arthroplasty as a treatment alternative both for surgeons and patients. The addition of reverse shoulder arthroplasty has been the driving force behind the explosive growth of arthroplasty and is now performed more often than anatomic shoulder arthroplasty. Although revision shoulder arthroplasty is primarily of interest to the subspecialist, it is a skill sought by the general orthopaedic surgeon. It is important for the orthopaedic surgeon to be knowledgeable about the planning, necessary skills, and management of basic shoulder arthroplasty.

The risk of postoperative scapular spine fracture following reverse shoulder arthroplasty is increased with an onlay humeral stem

BACKGROUND

The purpose of this study was to assess the effects of lateralization and distalization on scapular spine fracture (SSF) after reverse shoulder arthroplasty (RSA). The hypothesis was that postoperative distalization would increase the risk of SSF, whereas lateralization would not.

METHODS

A multicenter retrospective review was performed at a minimum of 1 year postoperatively on primary RSAs with 3 different implants, 2 with an inlay design (n = 342) and 1 with an onlay design (n = 84). Functional outcome, range of motion, stem design, and radiographic measurements, including acromiohumeral distance and lateralization, were compared between groups with and without fracture.

RESULTS

The incidence of SSF in the onlay group (11.9%) was significantly higher compared with the inlay group (4.7%; P = .043). Postoperative acromiohumeral distance was approximately 4 mm higher in the SSF group (37.5 mm) compared with the control group (33.7 mm; P = .042), whereas lateralization was similar between the 2 groups (52.8 mm vs. 53.9 mm; P = .362). Higher return to activity (92.1% vs. 71.4%; P < .001) as well as postoperative forward flexion was observed in the group without fracture (135° vs. 120°; P = .009).

CONCLUSION

Increased postoperative distalization is associated with an increased risk of SSF after RSA. An onlay stem resulted in a 10 mm increase in distalization compared with an inlay stem, and a 2.5 times increased risk of SSF. Lateralization, however, does not appear to increase the risk of SSF.

Acute surgical management of proximal humerus fractures: ORIF vs. hemiarthroplasty vs. reverse shoulder arthroplasty

BACKGROUND

Proximal humerus fracture treatment varies by surgeon preference and patient factors. This study compares patient and fracture characteristics, with outcomes between current surgical treatment options.

METHODS

Between 1999 and 2018, 425 proximal humerus fractures underwent acute surgical management: open reduction internal fixation (ORIF, n = 211), hemiarthroplasty (HA, n = 108), or reverse shoulder arthroplasty (RSA, n = 106). Patient and fracture characteristics included age, American Society of Anesthesiologists physical status classification (ASA), and fracture classification. Postoperative motion at 3, 6, and minimum 12 months (avg 20 ± 21 months), radiographic outcomes, and postoperative falls were analyzed.

RESULTS

Average age for treatment groups was 65 ± 13 years (range: 18-93 years). Fractures were classified as 2- (11%), 3- (41%), or 4-part (48%). Age, ASA, and fracture classification were associated with selected surgical management (P < .0001, =.001, <.0001, respectively). Outcomes showed a significant improvement in forward flexion from 3 months to 6 months in all groups (P < .0001). No difference in final motion was seen between groups. Radiographic union was higher in ORIF (89%), and similar between HA (79%) and RSA (77%, P = .005). Rate of reoperation was RSA 6.6%, ORIF 17.5%, and hemiarthroplasty 15.7% (P = .029). Postoperatively, 23% patients had at least 1 fall, of which 73% resulted in fractures.

CONCLUSION

Older patients with high ASA were treated with arthroplasty, and younger patients with lower ASA were treated with ORIF. All groups showed improvements in motion. At minimum 1 year of follow-up, there was no difference in motion between groups. ORIF and HA showed significantly more reoperations compared with RSA. Patients should be counseled about reoperation, fall risk, and prevention.

Defining the younger patient: age as a predictive factor for outcomes in shoulder arthroplasty

BACKGROUND

The purpose of this study was to define an age cutoff at which clinical outcomes and revision rates differ for patients undergoing primary anatomic total shoulder arthroplasty (TSA) and patients undergoing primary reverse shoulder arthroplasty (RSA).

METHODS

This retrospective cohort study included 1250 primary shoulder arthroplasties (1131 patients) with minimum 2-year clinical follow-up (mean, 50 months [range, 24-146 months]). TSA (n = 518; mean age, 68.1 years [range, 28-90 years]) was performed for osteoarthritis in most cases (99%), whereas the primary diagnoses for RSA (n = 732; mean age, 70.8 years [range, 22-91 years]) included rotator cuff arthropathy (35%), massive cuff tear without osteoarthritis (29.8%), and osteoarthritis (20.5%). Outcomes included range of motion, the American Shoulder and Elbow Surgeons (ASES) score, and the revision rate. The relationship between age at the time of surgery in 5-year increments (46-50 years, 51-55 years, and so on) and the revision rate was examined to identify the age cutoff; this was then used to assess clinical outcomes.

RESULTS

In patients younger than 65 years, TSA was associated with a 3.4-fold increased risk of revision (P = .01). RSA performed in patients younger than 60 years was associated with a 4.8-fold increased risk of revision (P < .001). TSA patients aged 65 years or older and RSA patients aged 60 years or older had better total ASES scores (82 vs. 77 [P = .03] and 72 vs. 62 [P = .002], respectively) and better internal rotation (interquartile range, TSA 5-6 vs. 4-5 [P = .002] and RSA 4-5 vs 3-4 [P = .04])-where 6 represents T4 to T6 and 4 represents T11 to L1-than their younger counterparts.

CONCLUSION

Age at index arthroplasty affects outcomes and the risk of revision. Primary TSA patients younger than 65 years and RSA patients younger than 60 years have a significantly increased revision risk. These age cutoffs are also correlated with differences in ASES scores and internal rotation.

Does the etiology of a failed hemiarthroplasty affect outcomes when revised to a reverse shoulder arthroplasty?

BACKGROUND

The purposes of this study were to evaluate patient outcomes after revision of hemiarthroplasty to reverse shoulder arthroplasty (RSA) based on initial pathology, to determine the re-revision rate, and to identify characteristics that may predict subsequent re-revision.

METHODS

A total of 207 shoulder hemiarthroplasty, bipolar prosthesis, and humeral resurfacing cases revised to RSA between January 2004 and January 2017 were reviewed. Outcome measures included shoulder motion and American Shoulder and Elbow Surgeons and Simple Shoulder Test (SST) scores. Sixteen RSAs underwent re-revision. A case-control study with each revised RSA matched to 4 controls based on age, sex, and minimum 2-year follow-up was performed to evaluate for factors predicting re-revision.

RESULTS

The mean time from initial hemiarthroplasty to RSA was 3.6 years (range, 0.1-20 years). There were 114 patients with a minimum of 2 years' follow-up (mean, 57 months; range, 24-144 months). The most common initial diagnoses for hemiarthroplasty were fracture (n = 72), cuff tear arthropathy (CTA) (n = 22), and osteoarthritis (OA) (n = 20). Overall mean scores and range-of-motion values were as follows: American Shoulder and Elbow Surgeons score, 59 (95% confidence interval [CI], 54-64); SST score, 4 (95% CI, 4-5); forward flexion, 106° (95% CI, 96°-116°); and abduction, 95° (95% CI, 85°-105°). Compared with fracture cases, CTA cases had better forward flexion (P = .01) and abduction (P = .006) and OA cases had better SST scores (P = .02) and abduction (P = .04). The re-revision rate was 7.7% at a mean of 31 months (range, 0-116 months), with the most common diagnosis being fracture (10 of 16 cases). Humeral loosening (8 of 16 cases) was the most common failure mechanism, and larger glenosphere sizes were more likely to be revised.

CONCLUSION

Functional outcome scores of hemiarthroplasty cases revised to RSA were better for patients with OA than for patients with CTA or fracture. Cases of hemiarthroplasty for fracture had decreased motion after revision to RSA compared with CTA and OA. Humeral loosening was the most common failure mechanism.

Influence of reverse total shoulder arthroplasty baseplate design on torque and compression relationship

Background

A linear relationship between baseplate insertion torque and compression force in reverse shoulder arthroplasty (RSA) baseplates with central screw design has been recently established. In this study, we evaluated 3 different baseplate designs and their influence on the torque-compression relationship.

Methods

Three different RSA baseplate designs were evaluated through biomechanical testing using a glenoid vault, bone surrogate model. A digital torque gauge was used to measure insertion torque applied to the baseplate, whereas compression data were collected continuously from a load cell. Additionally, 2 predictive models were developed to predict the compression forces of each baseplate design at varying levels of torque.

Results

A linear relationship was found between baseplate compression and insertion torque for all 3 baseplate designs. Both the monoblock and 2-piece locking designs achieved the goal torque of 6.8 Nm, whereas the 2-piece nonlocking design did not due to material strip-out. No significant difference in maximum compression was found between the monoblock and 2-piece locking designs. However, the 2-piece nonlocking design achieved significantly higher compression. Both predictive models were shown to adequately predict compressive forces at different torque inputs for the monoblock and 2-piece locking designs but not the 2-piece nonlocking design.

Conclusion

The torque-compression relationship of a central screw baseplate is significantly affected by baseplate design. A 2-piece nonlocking baseplate reaches higher compression levels and risks material strip-out at lower insertional torques compared with a monoblock and 2-piece locking design. This has implications both on component design and on surgeon tactile feedback during surgery.

Relationship Between Insertion Torque and Compression Strength in the Reverse Total Shoulder Arthroplasty Baseplate

Reverse shoulder arthroplasty is a well-established procedure, however, there is limited data in the literature regarding adequate insertion torque and the resulting compression for glenoid baseplate fixation. In this biomechanical study, we evaluated the relationship between insertion torque and baseplate compression by simultaneously measuring the insertion torque and axial compressive forces generated by two reverse shoulder arthroplasty baseplates with central screw design. Three different bone surrogates were chosen to mimic clinical scenarios where differences in compression achieved during baseplate insertion may exist due to varying bone quality. Epoxy resin sheets were combined with the bone surrogates to simulate the glenoid vault. A digital torque gauge was used to measure insertion torque applied to the baseplate, while compression data were collected continuously from a load cell. A strong positive correlation was found between baseplate compression and insertion torque. Among the lower density bone surrogates, neither baseplate design reached maximum insertion torque (6.8 Nm) due to material strip-out. This phenomenon did not occur in denser bone surrogates. Both baseplate designs experienced a significant increase in mean baseplate compression as insertion torque increased and were found to behave similar in the denser bone surrogates. The results presented here suggest that larger compressive forces can be achieved with an increase in insertion torque in denser bone surrogates, but caution must be used when trying to achieve fixation in poor-quality bone. Clinically, this could be useful preoperatively to minimize baseplate failure, and in further studies regarding baseplate design for improved initial fixation and stability. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:871-879, 2020.

Do preoperative radiographs help predict intraoperative challenges in revision surgery after previous shoulder hemiarthroplasty?

BACKGROUND

This study compares preoperative radiographic evaluation with intraoperative video and explant data in patients undergoing revision of a hemiarthroplasty.

METHODS

From 2004 to 2017, 182 shoulder hemiarthroplasties underwent revision to reverse shoulder arthroplasty for symptomatic failure. Preoperative radiographs were evaluated for stem fixation, stability, and glenohumeral registry. Intraoperative videos (n = 48) were evaluated for humeral component stability and bone loss after humeral stem extraction. All explants (n = 83) were reviewed for humeral head wear patterns and extraction artifacts (EAs).

RESULTS

A well-fixed stem was reliably identified on radiographs as well fixed (true-negative rate, 95%). Of cemented implants, 94% (97 of 103) were radiographically stable and 90% (18 of 20) were stable on intraoperative video. Significant proximal humeral bone loss was identified after cemented stem extraction in 83% of cases, and severe EAs were noted in 28% (14 of 50). Of uncemented implants, 95% (75 of 79) were radiographically stable and 96% (24 of 25) were operatively stable. Significant proximal humeral bone loss was identified after extraction in 36% of cases (9 of 25) (P = .001). Severe EAs were seen in 13% of explanted stems (3 of 23). Eccentrically worn humeral head explants were associated with eccentric glenohumeral registry in 84% of cases (P = .0075).

CONCLUSION

Preoperative radiographs for revision of a failed hemiarthroplasty help identify well-fixed stems and predict humeral bone loss during extraction. Cemented stems will have more EAs and result in greater bone loss than uncemented stems. Glenohumeral registry can help to predict humeral head wear. Eccentric registry leads to eccentric humeral head wear in 84% of cases.

Is there a relationship between preoperative diagnosis and clinical outcomes in reverse shoulder arthroplasty? An experience in 699 shoulders

BACKGROUND

The influence of diagnosis on outcomes after reverse shoulder arthroplasty (RSA) is not completely understood. The purpose of this study was to compare clinical outcomes of different pathologies.

METHODS

A total of 699 RSAs were performed for the following diagnoses: (1) rotator cuff tear arthropathy (RCA), (2) massive cuff tear (MCT) with osteoarthritis (OA), (3) MCT without OA, (4) OA, (5) acute proximal humeral fracture, (6) malunion, (7) nonunion, and (8) inflammatory arthropathy. All patients had minimum 2-year clinical follow-up (mean, 47 months; range, 24-155 months). Range of motion, Simple Shoulder Test scores, American Shoulder and Elbow Surgeons scores, visual analog scale scores for function, and health-related quality-of-life measures were obtained preoperatively and postoperatively.

RESULTS

The RCA, MCT-with-OA, MCT-without-OA, and OA groups all exhibited significant improvements in all outcome scores and in all planes of motion from preoperatively until a minimum of 2 years postoperatively. The malunion, nonunion, and inflammatory arthropathy groups showed improvements in American Shoulder and Elbow Surgeons scores, Simple Shoulder Test scores, forward flexion, and abduction. The average changes for all other outcomes and planes of motions were also positive but did not reach statistical significance. After adjustment for age and compared with RCA, female patients with malunion had significantly poorer forward flexion (P < .05), those with OA had significantly better abduction (P < .05), and those with fractures had significantly worse patient satisfaction (P < .05). Among male patients, those with MCTs without OA had significantly worse satisfaction (P < .05).

CONCLUSION

RSA reliably provides improvement regardless of preoperative diagnosis. Although subtle differences exist between male and female patients, improvements in clinical outcome scores were apparent after RSA.

Massive Rotator Cuff Tears in Patients Older Than Sixty-five: Indications for Cuff Repair versus Reverse Total Shoulder Arthroplasty

The decision to perform rotator cuff repair (RCR) versus reverse total shoulder arthroplasty (rTSA) for massive rotator cuff tear (MCT) without arthritis can be difficult. Our aim was to identify preoperative variables that are influential in a surgeon's decision to choose one of the two procedures and evaluate outcomes. We retrospectively reviewed 181 patients older than 65 who underwent RCR or rTSA for MCT without arthritis. Clinical and radiographic data were collected and used to evaluate the preoperative variables in each of these two patient populations and assess outcomes. Ninety-five shoulders underwent RCR and 92 underwent rTSA with an average followup of 44 and 47 months, respectively. Patients selected for RCR had greater preoperative flexion (113 vs 57), abduction (97 vs 53), and external rotation (42 vs 32), higher SST (3.1 vs 1.9) and ASES scores (43.8 vs 38.6), and were less likely to have had previous cuff surgery (6.3% vs 35.9%). Patients selected for rTSA had a smaller acromiohumeral interval (4.8 vs 8.7) and more superior subluxation (50.6% vs 14.1%). Similar preoperative characteristics included pain, comorbidities, and BMI. Patients were satisfied in both groups and had significant improvement in motion and function postoperatively. Both RCR and rTSA can result in significant functional improvement and patient satisfaction in the setting of MCT without arthritis in patients older than 65. At our institution, patients who underwent rTSA had less pre-operative motion, lower function, more evidence of superior migration, and were more likely to have had previous rotator cuff surgery.

Clinical outcomes following reverse shoulder arthroplasty-allograft composite for revision of failed arthroplasty associated with proximal humeral bone deficiency: 2- to 15-year follow-up

BACKGROUND

Patients with pain and disability due to a prior failed shoulder arthroplasty with associated proximal humeral bone loss have limited reconstruction options. Our purpose was to report the results of a large cohort of patients treated with a reverse shoulder allograft-prosthetic composite (APC).

METHODS

Between 2002 and 2012, a total of 73 patients were treated with a reverse shoulder APC and had adequate follow-up. Clinical outcome scores, range of motion, and radiographic evidence of failure were assessed. The minimum follow-up period was 2 years, with an average of 67.9 months (range, 21-157 months). Of the patients, 43 had more than 5 years' follow-up and 12 had more than 10 years' follow-up.

RESULTS

The total American Shoulder and Elbow Surgeons score improved from 33.8 to 51.4 (P < .0001), and the Simple Shoulder Test score improved from 1.3 to 3.5 (P < .0001). Good to excellent results were reported in 42 of 60 patients (70%), 10 patients (17%) reported satisfactory results, and 8 patients (13%) were unsatisfied. Range of motion improved in forward flexion (49° to 75°, P < .001) and abduction (45° to 72°, P < .001). Revision was required in 14 patients (19%) for periprosthetic fracture (n = 6), instability (n = 2), glenosphere dissociation (n = 2), humeral loosening (n = 2), and infection (n = 2) at a mean of 38 months postoperatively. The reoperation-free survival rate of all reconstructions was 88% (30 of 34) at 5 years, 78% (21 of 27) at 10 years, and 67% (8 of 12) beyond 10 years. Ten patients had radiographic evidence of humeral loosening at final follow-up, and 2 required revision.

CONCLUSIONS

The use of a reverse total shoulder APC provides reliable pain relief and improved range of motion, with an acceptable rate of complications. Although ultimate function achieved is limited, patient satisfaction remains high.

Quantitative videographic analysis of intraoperative total shoulder arthroplasty is predictive of radiographic implant loosening

Background

It is believed that both patient and surgeon factors contribute to premature implant loosening. This video study was designed to answer the following questions: Can orthopedic surgeons reliably differentiate between procedures done well and those that will lead to early glenoid failure? Do the difficulty of the operation and the surgeon's performance predict a patient's outcome? Does the presence of a Walch B2 glenoid result in surgery that is evidently more difficult and performed in such a way to suggest early glenoid component failure?

Methods

Eleven upper extremity surgeons blindly graded a set of intraoperative videos of 15 total shoulder arthroplasty patients (grouped by outcome at 2 years). Evaluation questionnaires consisted of questions about the perceived difficulty and the surgeon's performance. Total and partial patient scores were calculated for each video. Higher calculated score would indicate worse postsurgical outcome.

Results

The loosening group had a significantly higher total score (P = .0057). Also, patients with B2 glenoids scored significantly higher than patients with other wear type. The analysis of overall procedure performance indicated difference between outcome groups (P = .0063).

Conclusion

Our results indicate that surgeons could review surgical videos and differentiate the cases that were difficult or those that were more likely to lead to loosening of the glenoid component. The presence of a B2 glenoid was predictive of difficult surgery. The results of this study should serve as a starting point for surgeons interested in critically evaluating performance and also for those interested in finding ways to maximize patient outcomes after total shoulder arthroplasty.

Management of Three- and Four-Part Proximal Humerus Fractures

The management of three- and four-part proximal humerus fractures remains controversial because the literature has supported all forms of management, including nonsurgical management, open reduction and internal fixation (ORIF), and shoulder arthroplasty. Specific patient factors ultimately influence the decision of which treatment best fits the patient and the fracture. Surgeons should understand the rationale for nonsurgical and surgical management of these fractures, including ORIF and reverse shoulder arthroplasty.

Classification of instability after reverse shoulder arthroplasty guides surgical management and outcomes

BACKGROUND

Revision of unstable reverse shoulder arthroplasty (RSA) remains a significant challenge. The purpose of this study was to determine the reliability of a new treatment-guiding classification for instability after RSA, to describe the clinical outcomes of patients stabilized operatively, and to identify those with higher risk of recurrence.

METHODS

All patients undergoing revision for instability after RSA were identified at our institution. Demographic, clinical, radiographic, and intraoperative data were collected. A classification was developed using all identified causes of instability after RSA and allocating them to 1 of 3 defined treatment-guiding categories. Eight surgeons reviewed all data and applied the classification scheme to each case. Interobserver and intraobserver reliability was used to evaluate the classification scheme. Preoperative clinical outcomes were compared with final follow-up in stabilized shoulders.

RESULTS

Forty-three revision cases in 34 patients met the inclusion for study. Five patients remained unstable after revision. Persistent instability most commonly occurred in persistent deltoid dysfunction and postoperative acromial fractures but also in 1 case of soft tissue impingement. Twenty-one patients remained stable at minimum 2 years of follow-up and had significant improvement of clinical outcome scores and range of motion. Reliability of the classification scheme showed substantial and almost perfect interobserver and intraobserver agreement among all the participants (κ = 0.699 and κ = 0.851, respectively).

DISCUSSION

Instability after RSA can be successfully treated with revision surgery using the reliable treatment-guiding classification scheme presented herein. However, more understanding is needed for patients with greater risk of recurrent instability after revision surgery.

Humeral Bone Loss in Revision Shoulder Arthroplasty

Revision shoulder arthroplasty is becoming more prevalent as the rate of primary shoulder arthroplasty in the US continues to increase. The management of proximal humeral bone loss in the revision setting presents a difficult problem without a clear solution. Different preoperative diagnoses often lead to distinctly different patterns of bone loss. Successful management of these cases requires a clear understanding of the normal anatomy of the proximal humerus, as well as structural limitations imposed by significant bone loss and the effect this loss has on component fixation. Our preferred technique differs depending on the pattern of bone loss encountered. The use of allograft-prosthetic composites, the cement-within-cement technique, and combinations of these strategies comprise the mainstay of our treatment algorithm. This article focuses on indications, surgical techniques, and some of the published outcomes using these strategies in the management of proximal humeral bone loss.

Massive Rotator Cuff Tear: When to Consider Reverse Shoulder Arthroplasty

PURPOSE OF REVIEW

The purpose of this review is to discuss the indications for reverse shoulder arthroplasty (RSA) in the treatment of massive rotator cuff tear (MCT), review the reported outcomes in the literature, and outline our approach and surgical technique for treating these patients.

RECENT FINDINGS

While RSA remains a successful and well-accepted treatment for cuff tear arthropathy (CTA), management of MCT in the absence of arthritis is controversial. In this particular setting, patients best suited for RSA are elderly, lower-demand individuals with chronic, irreparable MCT, and pseudoparalysis. Age < 60, better pre-operative function and upper extremity neurologic dysfunction are potential risk factors for poor outcome with RSA in this population. Long-term follow-up studies of RSA for CTA and MCT show good functional outcomes and implant survival > 90% at 10 years. Treatment of MCT must be individualized for each patient. When patient selection is optimized, RSA is a reliable means of relieving pain and improving function with excellent success. Further investigation is necessary to better define its indications and assess the role of alternative, joint-salvaging procedures.

Reverse Shoulder Arthroplasty for the Treatment of Rotator Cuff Deficiency: A Concise Follow-up, at a Minimum of 10 Years, of Previous Reports

We previously evaluated 94 patients (96 shoulders) who underwent reverse shoulder arthroplasty using a central compressive screw with 5.0-mm peripheral locking screws for baseplate fixation and a center of rotation lateral to the glenoid as treatment for end-stage rotator cuff deficiency. The purpose of this study was to report updated results at a minimum follow-up of 10 years. Forty patients (42 shoulders) were available for clinical follow-up. In the patients available for study, implant survivorship, with the end point being revision for any reason, was 90.7%. Since our 5-year report, 2 patients underwent revision surgery; 1 patient sustained a periprosthetic fracture 7 years postoperatively and 1 patient had a dislocation because of chronic shoulder instability at 8 years postoperatively. At a minimum follow-up of 10 years, the patients continued to maintain their improved outcome scores and range of motion, which were comparable with earlier follow-up evaluations.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Large diaphyseal-incorporating allograft prosthetic composites: when, how, and why : Treatment of advanced proximal humeral bone loss

BACKGROUND

Proximal humeral bone loss in shoulder arthroplasty is a complex problem with a heterogeneous presentation. Different etiologies may contribute to varying degrees of severity in bone loss that dictate different treatment approaches.

OBJECTIVES

The purpose of this is article is to describe our technique for treatment of proximal humeral bone loss with proximal humeral allograft prosthetic composites (APC) and identify factors that may predict when larger allografts may be necessary.

MATERIALS AND METHODS

Ninety-nine patients were identified that had undergone reverse total shoulder arthroplasty with use of a proximal humeral allograft. Thirty-nine of these had large allografts that involved a significant portion of the diaphysis. Preoperative characteristics were examined to identify factors that may be associated with use of a larger diaphyseal-incorporating allograft.

RESULTS

Well-fixed humeral stems could be treated with short metaphyseal allografts in 55 of 65 (85%) cases. Loose stems required longer diaphyseal-incorporating allografts in 28 of 31 (90%) cases, and these were commonly associated with periprosthetic fractures (n = 10), failed prior APC (n = 6), and infection (n = 5). Noncemented stems required diaphyseal grafts in 75% of cases, compared to cemented stems which required larger grafts in 34% of cases.

CONCLUSIONS

Proximal humeral bone loss in the setting of revision shoulder arthroplasty can be successfully managed with a reverse total shoulder and proximal humeral allograft. Larger allografts are frequently required for loose humeral stems, and noncemented stems appear more likely to require larger allografts than cemented stems.

Morphometry of the human clavicle and intramedullary canal: A 3D, geometry-based quantification

Midshaft clavicle fractures are a very common occurrence. The current treatment of choice involves internal fixation with superior or anterior clavicle plating, however their clinical success and particularly patient satisfaction are decreasing. The implementation of intramedullary devices is on the rise, but data describing the intramedullary canal parameters are lacking. The aim of this study is to quantify the geometry of the clavicle and its intramedullary canal, and to evaluate the effect of gender and anatomical side. This study used three-dimensional image-based models with novel and automated methods of standardization, normalization, and bone cross-section evaluation. The data obtained in this study present intramedullary canal, and clavicle diameter and center deviation parameterized as a function of clavicle length as well as its radius of curvature and true length. Results showed that both right-sided and female clavicles were shorter and thicker, but only females showed a statistically significant difference in size compared to males (p < 0.0001). The smallest clavicle and intramedullary canal diameters were seen at different clavicle lengths (45% and 52%), suggesting that the narrowest region of intramedullary canal cannot be appreciated based on external visualization of the clavicle alone. The narrowing of the intramedullary canal is of special interest because this is a potential limiting region for surgical planning and intramedullary device design. Furthermore, the location and value of maximum lateral curvature displacement is different in the intramedullary canal, implying there exists an eccentricity of the intramedullary canal center with respect to the clavicle center. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2191-2202, 2017.

Bone Graft Augmentation for Severe Glenoid Bone Loss in Primary Reverse Total Shoulder Arthroplasty: Outcomes and Evaluation of Host Bone Contact by 2D-3D Image Registration

Background:

The treatment of patients with severe glenoid bone loss using reverse total shoulder arthroplasty (RSA) is challenging because of the difficulty in obtaining glenoid fixation. The outcomes following primary RSA with structural bone-grafting for severe glenoid bone loss and the amount of native bone support necessary to achieve clinical improvement are unclear.

Methods:

We reviewed functional outcomes (American Shoulder and Elbow Surgeons [ASES] score, Simple Shoulder Test [SST], visual analog scale [VAS] for pain and function, patient satisfaction, and range of motion) for 57 patients who were treated with a primary RSA and glenoid bone-grafting for severe glenoid bone loss. Three glenoids were classified as type A2; 2, as type B2; and 2, as type C, according to the Walch classification; 16 glenoids, as grade E1; and 19, as grade E3, according to the Sirveaux classification; 9 glenoids, as grade 3, according to the Levigne classification; and 6 were unable to be classified. For the 44 patients with adequate preoperative computed tomographic (CT) data and postoperative radiographs, we evaluated native bone contact under the glenoid baseplate by matching the projected shape of the implant and scapula from the postoperative radiographs with a generated 3-dimensional (3D) model of the preoperative scapula. We then analyzed functional outcomes in relation to native bone support of the baseplate.

Results:

At a mean of 46 months (minimum, 24 months), the patients demonstrated significant improvements in function, motion, and pain (change in the ASES total score = 38.6, change in SST = 5.4, change in forward elevation = 72.4°, change in abduction = 67.7°, change in external rotation = 24.3°, and change in VAS pain score = −4.6; p < 0.001 for all). On the basis of the generated 3D model, the baseplate contact to host bone was a mean (and standard deviation) of 17% ± 12% (range, 0% to 50%). There was no significant correlation between host bone coverage and change in the ASES score (p = 0.51) for the 44 patients included in this analysis. There were 4 major complications (7%) in the study group but no glenoid baseplate failures.

Conclusions:

Glenoid bone-grafting in a primary RSA in a shoulder with severe bone loss produces good functional outcomes that do not correlate with the degree of native bone contact under the baseplate. We had observed no glenoid component failures at the time of writing.

Level of Evidence:

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.