Standard versus bony increased-offset reverse shoulder arthroplasty: a retrospective comparative cohort study

BACKGROUND

To date, only a few comparative studies with small sample sizes have compared a traditional reverse shoulder arthroplasty (tRSA) to a bony increased-offset RSA (BIO-RSA). We hypothesized that the BIO-RSA would lead to lower notching rates and improved range of motion (ROM) compared with a tRSA.

METHODS

A retrospective review was performed of 69 tRSAs and 61 BIO-RSAs performed by a single surgeon. At 2 years postoperative, ROM and Constant scores were compared. Radiographs were examined for scapular notching, scapular spurring or ossification, and graft healing.

RESULTS

At the 2-year follow-up, the BIO-RSA group demonstrated improved anterior forward flexion compared with the tRSA group (145° ± 20° vs. 138° ± 20°, respectively; P = .017). There was no difference in external or internal rotation between the 2 groups. The BIO-RSA group had a higher Constant score than the tRSA group (69 ± 9 vs. 61 ± 13; P < .001). The radiographs showed no difference between the 2 groups, including scapular notching (P = .150).

CONCLUSION

At the 2-year follow-up, BIO-RSA does not lead to a clinically significantly improvement in ROM, Constant scores, or change in scapular notching compared with a tRSA.

Coupling between 3D displacements and rotations at the glenohumeral joint during dynamic tasks in healthy participants

BACKGROUND

Glenohumeral displacements assessment would help to design shoulder prostheses with physiological arthrokinematics and to establish more biofidelic musculoskeletal models. Though displacements were documented during static tasks, there is little information on their 3D coupling with glenohumeral angle during dynamic tasks. Our objective was to characterize the 3D glenohumeral displacement-rotation couplings during dynamic arm elevations and rotations.

METHODS

Glenohumeral displacements were measured from trajectories of reflective markers fitted on intracortical pins inserted into the scapula and humerus. Bone geometry was recorded using CT-scan. Only four participants were recruited to the experiment due to its invasiveness. Participants performed dynamic arm abduction, flexion and axial rotations. Linear regressions were performed between glenohumeral displacements and rotations. The pin of the scapula of one participant moved, his data were removed from analysis, and results are based on three participants.

FINDINGS

The measurement error of glenohumeral kinematics was less than 0.15mm and 0.2°. Maximum glenohumeral displacements were measured along the longitudinal direction and reached up to +12.4mm for one participant. Significant couplings were reported especially between longitudinal displacement and rotation in abduction (adjusted R(2) up to 0.94).

INTERPRETATION

The proposed method provides the potential to investigate glenohumeral kinematics during all kinds of movements. A linear increase of upward displacement during dynamic arm elevation was measured, which contrasts with results based on a series of static poses. The systematic investigation of glenohumeral displacements under dynamic condition may help to provide relevant recommendation for the design of shoulder prosthetic components and musculoskeletal models.

Subscapularis and deltoid preserving anterior approach for reverse shoulder arthroplasty

HYPOTHESIS

We hypothesize that performing a RSA using an anterior approach without cutting the subscapularis tendon and the deltoid muscle could provide patients with superior short-term clinical outcomes and immediate active range of motion (ROM) without immobilization.

METHODS

Between August 2013 and June 2015, all patients who had a primary RSA were considered potentially eligible for inclusion in this prospective study.

RESULTS

No immediate intra- or postoperative complications were noted. A statistically significant improvement of VAS (from 6.7 to 1; P<.001), SANE (from 34 to 80; P<.001), and elevation (from 103° to 128°; P=.02) was observed. In some cases, patients who had pseudoparalysis preoperative were able to achieve full anterior elevation few days after the operation.

DISCUSSION

Using a subscapularis and deltoid preserving anterior approach is an option for patients requiring RSA. Leaving this tendon intact and preserving the deltoid minimize the need for immediate postoperative immobilization and allow for faster recovery of shoulder ROM, without risking the concern of humeral anterior dislocation. Overall duration of hospital stay as well as length of postoperative physical therapy may be minimized, with substantial long-term economic gain. Longer follow-up and comparison with standard approaches is necessary in the future.

LEVEL OF EVIDENCE OF THE STUDY

Level IV, case series with no comparative group.

Reverse versus anatomical shoulder arthroplasty in patients with intact rotator cuff

PURPOSE

The study objective was to compare the clinical results of reverse total shoulder arthroplasty (rTSA) and anatomical total shoulder arthroplasty (aTSA) in patients with osteoarthritis and intact rotator cuff. We hypothesised that the clinical results using rTSA would be comparable with those obtained with aTSA in this group of patients.

METHODS

The study included 51 patients with shoulder osteoarthritis and intact rotator cuff who underwent rTSA or aTSA. The range of motion, Constant-Murley score and strength in external rotation were recorded pre-operatively and at the two year follow-up. Subjective post-operative results were measured using the subjective shoulder value (SSV) score and a satisfaction questionnaire.

RESULTS

The post-operative improvement was significant in both groups, subjectively and concerning all parameters of the Constant-Murley score. Post-operatively, no significant difference was noted between the two groups for active anterior elevation (AAE), active external rotation (ER), internal rotation (IR) or Constant-Murley score (67 ± 12 in the rTSA group vs 71 ± 11 in the aTSA group). An exception was the Constant-Murley range of motion sub-score, which was better in the aTSA group (p = 0.028). No significant complications necessitating revision surgery were encountered.

DISCUSSION

Our findings are consistent with previous studies showing good results of rTSA with shoulder osteoarthritis and intact rotator cuff with a good restoration of the IR, similar to that obtained with aTSA.

CONCLUSION

The rTSA is a valid option for shoulder osteoarthritis and intact rotator cuff in older adult patients.

Shoulder Arthroplasty: Historical Considerations

BACKGROUND

The first articular metal prosthesis was implanted in the shoulder more than 120 years ago. The aim of this paper is to report shoulder arthroplasty evolution during this time thru the literature of the twentieth century.

METHODS

A literature review was performed selecting the founding papers about shoulder arthroplasty.

RESULTS

After being almost forgotten during the first part of the 20th century, various implants were introduced in the 1950s with Charles Neer as a leader. The reverse concept appeared in the 1970s and knew many failures before Grammont's design.

CONCLUSION

After many unfortunate trials, the shoulder prosthesis is now widely disseminated with products of many companies.

Benefits of iterative metal artifact reduction and dual-energy CT towards mitigating artifact in the setting of total shoulder prostheses

OBJECTIVE

To determine the utility of iterative metal artifact reduction and 130 keV dual-energy virtual monoenergetic images to improve bone and soft tissue visualization in CT scans affected by metal artifacts.

MATERIAL AND METHODS

Thirteen females and 6 males with a history of total shoulder prosthesis who underwent dual-energy shoulder CT were included. Four sets of images were reconstructed for each patient: (1) original polychromatic kV images reconstructed with weighted filtered back projection; (2) polychromatic kV images with iterative metal artifact reduction; (3) 130 keV dual-energy virtual monoenergetic; (4) combined iterative metal artifact reduction and 130 keV dual-energy virtual monoenergetic. Three readers blindly reviewed all image sets and graded the extent of artifact and image quality.

RESULTS

Mean artifact score and median overall image quality score were better in 130 keV dual-energy virtual monoenergetic with iterative metal artifact reduction compared with those in original polychromatic kV images (3.02 vs 4.28, P < 0.001 and 3.00 vs 4.33, P < 0.001, respectively). The median difference in CT numbers between regions affected by artifacts and normal regions was lowest in 130 keV dual-energy virtual monoenergetic with iterative metal artifact reduction compared with that in original polychromatic kV images (72.28 vs 252.08, P < 0.001 for bony regions and 15.09 vs 324.38, P < 0.001 for soft tissue).

CONCLUSION

In patients with metal artifacts due to shoulder replacement surgery, the use of dual-energy monoenergetic images and iterative metal artifact reduction reconstruction significantly improves both subjective and objective indicators of image quality.

Views on a new surgical assistance method for implanting the glenoid component during total shoulder arthroplasty. Part 2: From three-dimensional reconstruction to augmented reality: Feasibility study

INTRODUCTION

The main goal of this study was to propose a new method of surgical assistance for the implantation of a total shoulder prosthesis, with the use of augmented reality (AR). The advantage of this approach is that it supplements information, on the one hand pre-existing or disappeared due to a pathological process, such as the premorbid glenoid, and on the other hand already existing but not accessible to the surgeon during the procedure, such as the so-called "hidden" face of the scapula.

MATERIAL AND METHODS

Several information preparation steps were needed. The first consisted in the three-dimensional (3D) rendering of the pathological glenoid, from a point cloud corresponding to the premorbid glenoid based on previously developed regression equations. A library of "healthy" generic glenoids was then created by hierarchical bottom-up analysis. From this database, a so-called adequate normal generic glenoid was fused and matched to the pathological glenoid reconstructed using a morphing technique. An experimental AR application was constructed. Smart glasses were used to display the prepared 3D information.

RESULTS

A pathological 3D glenoid was reconstructed and used for the AR application. A complete display of the scene, reconstructed glenoid and full scapula was obtained. However, an offset from reality was observed. The main limitations were technical, related to the connected tool itself and the operating software.

DISCUSSION/CONCLUSION

This was a feasibility study of the different steps required to apply AR, from information preparation to its visualization. A new parameter crossing experiment is needed to optimize each step of this process.

LEVEL OF EVIDENCE

IV, Basic science study.

Patient-reported outcome after stemmed versus stemless total shoulder arthroplasty for glenohumeral osteoarthritis: a patient-blinded randomized clinical trial

BACKGROUND

Stemless shoulder arthroplasty systems with uncemented metaphyseal fixation have been used for glenohumeral osteoarthritis since 2004 (Hawi, et al. BMC Musculoskelet Disord 17:376, 2016). The stemless design has several theoretical advantages compared with the stemmed shoulder arthroplasty systems: restoring patients' anatomy; preserving humeral bone stock; and few complications in component removal if the need for a revision arthroplasty arises. The purpose of the study is to compare the short-term, patient-reported outcome of stemless and stemmed total shoulder arthroplasty (TSA).

MATERIALS AND METHODS

A randomized clinical trial will be conducted. Eighty patients with clinical and radiological signs of primary or post-traumatic glenohumeral osteoarthritis, computed tomography (CT) scan-verified adequate glenoid bone stock, and no total rupture of rotator cuff tendons verified by a magnetic resonance imaging (MRI) scan will be randomly allocated to a stemless or stemmed TSA. The primary outcome will be the Western Ontario Osteoarthritis Shoulder (WOOS) score at 12 months. Secondary outcomes are the WOOS score at three months and the Oxford Shoulder Score (OSS) and EQ-5D at 3 and 12 months. All complications, including glenoid and humeral component loosening, instability, rotator cuff tear, intraoperative and postoperative periprosthetic fracture, nerve injury, infection, deltoid injury, and symptomatic deep venous thrombosis, will be reported.

DISCUSSION

Findings will provide patients with better information about the potential benefits and harms of stemless and stemmed TSA and will assist shoulder surgeons and patients in decision-making.

TRIAL REGISTRATION

Clinicaltrials.gov, NCT03877315 . Registered on 13 March 2019.

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.

Are Cutibacterium acnes present at the end of primary shoulder prosthetic surgeries responsible for infection? Prospective study

The purpose of this study was to investigate if the C. acnes present at the end of a primary shoulder arthroplasty could be responsible for shoulder arthroplasty infection. Prospective study includes patients undergoing primary shoulder arthroplasty from January 2015 until December 2018. From all the patients included, 5 to 12 tissue samples were obtained and were specifically cultured to detect the presence of C. acnes. DNA was extracted from the C acnes isolated colonies and Whole Genome Sequencing (WGS) analysis was done. A cohort of 156 patients was finally included. In twenty-seven patients, the C. acnes was present at the end of the primary surgery. Two of these patients developed a C. acnes periprosthetic shoulder infection at 6 and 4 months after the primary surgery. WGS of C. acnes isolated colonies showed that all the revision-surgery isolates clustered near to the corresponding primary-surgery isolates compared to the other independent bacterial colonies. (99.89% of similarity). C. acnes present at the end of the primary surgery can be the cause of early or delayed periprosthetic joint infections in shoulder arthroplasty.

Clinical results and radiological bony adaptations on a cementless short-stem prosthesis - A comparative study between anatomical and reverse total shoulder arthroplasty

INTRODUCTION

Although the use of short stem and stemless shoulder prosthesis is trending, the surgical outcome may vary due to varying biomechanics. Objectives were to evaluate and compare the short-term clinical results and radiological changes between anatomical total shoulder arthroplasty (TSA) and reverse TSA (rTSA) with a short-stem humeral design.

HYPOTHESIS

There is no clinical and radiological difference between TSA and rTSA using a short-stem humeral design.

METHODS

This retrospective study included 66 patients who underwent TSA and rTSA (33 patients each) with a minimum 2-year follow-up. Radiographic findings, including preoperative Tingart cortical index (TCI), postoperative filling ratios of metaphysis (FRmet) and diaphysis (FRdia), bone adaptations, and osteolysis around the humeral stem at the immediate postoperative period, and the most recent follow-up were measured. Pre and postoperative Constant-Murley score, subjective shoulder value (SSV), and complications were noted.

RESULTS

At a mean follow-up of 27 (range 24-50) months, FRmet was significantly higher in rTSA group than the TSA group (0.65 vs. 0.60, p=0.009). Bone resorption was similar in both groups (p=0.76) and was correlated to a lower TCI value of<2.9mm (p=0.02). Despite significant clinical improvement in individual groups, the comparison between groups was non-significant (p>0.05). Negative correlation was observed between TCI and total clinical score (p=0.045) in TSA group, active external rotation (p=0.019), activity (p=0.005), SSV (p=0.008) and total score (p=0.025) in rTSA group. Radiographic changes were not influenced by patient characteristics and clinical results (p>0.05).

CONCLUSION

Although no radiographic difference was observed between TSA and rTSA, better short-term clinical results observed with the usage of the short-stem humeral design prosthesis are encouraging.

LEVEL OF EVIDENCE

III; Retrospective cohort study.

Shoulder Arthroplasty Imaging: What's New

Background

Shoulder arthroplasty, in its different forms (hemiarthroplasty, total shoulder arthroplasty and reverse total shoulder arthroplasty) has transformed the clinical outcomes of shoulder disorders. Improvement of general clinical outcome is the result of stronger adequacy of the treatment to the diagnosis, enhanced surgical techniques, specific implanted materials, and more accurate follow up. Imaging is an important tool in each step of these processes.

Method

This article is a review article declining recent imaging processes for shoulder arthroplasty.

Results

Shoulder imaging is important for shoulder arthroplasty pre-operative planning but also for post-operative monitoring of the prosthesis and this article has a focus on the validity of plain radiographs for detecting radiolucent line and on new Computed Tomography scan method established to eliminate the prosthesis metallic artefacts that obscure the component fixation visualisation.

Conclusion

Number of shoulder arthroplasties implanted have grown up rapidly for the past decade, leading to an increase in the number of complications. In parallel, new imaging system have been established to monitor these complications, especially component loosening.

Treatment of proximal humerus fractures using reverse shoulder arthroplasty: do the inclination of the humeral component and the lateral offset of the glenosphere influence the clinical outcome and tuberosity healing?

INTRODUCTION

The employment of reverse shoulder arthroplasty for dislocated proximal humerus fractures of elderly patients becomes increasingly relevant. The standard inclination angle of the humeral component was 155°. Lately, there is a trend towards smaller inclination angles of 145° or 135°. Additionally, there has been an increased focus on the lateralization of the glenosphere. This retrospective comparative study evaluates clinical and radiological results of patients treated for proximal humerus fractures by reverse shoulder arthroplasty with different inclination angles of the humeral component, which was either 135° or 155°. Additionally, a different lateral offset of the glenosphere, which was either 0 mm or 4 mm, was used.

METHODS

For this retrospective comparative analysis, 58 out of 66 patients treated by reverse total shoulder arthroplasty for proximal humerus fractures were included. The minimum follow-up was 24 months. Thirty (m = 3, f = 27; mean age 78 years; mean FU 35 months, range 24-58 months) were treated with a standard 155° humeral component and a glenosphere without lateral offset (group A), while 28 patients (m = 2, f = 26; mean age 79 years; mean FU 30 months, range 24-46 months) were treated with a 135° humeral component and a glenosphere with a 4 mm lateral offset (group B). We determined range of motion, Constant score, and the American Shoulder and Elbow Surgeons Shoulder score as clinical outcomes and evaluated tuberosity healing as well as scapula notching.

RESULTS

Neither forward flexion (A = 128°, B = 121°; p = 0.710) nor abduction (A = 111°, B = 106°; p = 0.327) revealed differences between the groups. The mean Constant Score rated 63 in group A, while it was 61 in group B (p = 0.350). There were no differences of the ASES Score between the groups (A = 74, B = 72; p = 0.270). There was an increased risk for scapula notching in group A (47%) in comparison to group B (4%, p = 0.001). Healing of the greater tuberosity was achieved in 57% of group A and in 75% of group B (p = 0.142). The healing rate of the lesser tuberosity measured 33% in group A and 71% in group B (p = 0.004).

CONCLUSIONS

Both inclination angles of the humeral component are feasible options for the treatment of proximal humerus fractures in elderly patients. Neither the inclination angle nor the lateral offset of the glenosphere seem to have a relevant influence on the clinical outcome. The healing rate of the lesser tuberosity was higher in implants with a decreased neck-shaft angle. There is an increased risk for scapula notching, if a higher inclination angle of the humeral component is chosen.

LEVEL OF EVIDENCE

III. Retrospective comparative study.

Complications of shoulder arthroplasty: added value of SPECT/CT imaging

The incidence of prosthetic shoulder replacements has increased considerably in recent years, as well as the complications derived from the procedure. The correct diagnosis of each type of complication is essential for therapeutic decision making, which is currently based on the information provided by radiological and nuclear medicine imaging. Nevertheless, both techniques have intrinsic limitations that could be mostly overcome with the advent of the hybrid SPECT/CT imaging, which is set to play a fundamental role in the evaluation of shoulder prostheses.

Early migration of stemless and stemmed humeral components after total shoulder arthroplasty for osteoarthritis-study protocol for a randomized controlled trial

BACKGROUND

Glenohumeral osteoarthritis can, in the most severe cases, require surgery with insertion of a shoulder arthroplasty. A design with a stem in the humeral bone canal is currently regarded as the standard treatment option in patients who have an intact rotator cuff function, but complications related to the stem including humeral fractures can have devastating consequences. By using a stemless humeral component, stem-related complications can be reduced. The aim of this study is to compare the Comprehensive Nano stemless total shoulder arthroplasty (intervention group) with the Comprehensive stemmed total shoulder arthroplasty (control group).

MATERIALS AND METHODS

This is a randomized controlled trial comparing the stemless and the stemmed total shoulder arthroplasty. All Danish citizens with glenohumeral osteoarthritis indicating a total shoulder arthroplasty referred to the orthopedic department at Copenhagen University Hospital in Herlev/Gentofte will be offered participation. The following exclude from participation: below 18 years of age, cognitive or linguistic impairment, insufficient function of the rotator cuff, poor bone quality, and ASA groups 4-5. A total of 122 patients will be included of which 56 will be part of a radiostereometric analysis (RSA) study of humeral component migration. The primary outcomes are magnitude of migration of the humeral component assessed by RSA and patient-reported outcome by Western Ontario Osteoarthritis of the Shoulder index (WOOS). The secondary outcomes are additional patient-reported outcomes, functional outcome, readmission, complications, revisions, and changes in bone mineral density (BMD) of the proximal humerus assessed by duel energy x-ray absorptiometry (DXA) and economy (cost-utility analysis). The patients are examined before the operation and 3, 6, 12, and 24 months postoperative.

DISCUSSION

To our knowledge, RSA has never been used to access migration of a stemmed or a stemless humeral component nor has the stemmed and the stemless humeral component been compared with regard to pain relief and shoulder function in a randomized clinical trial. Today, the two designs are considered equal in the treatment of osteoarthritis. The study will provide surgeons and patients with information about shoulder arthroplasty for osteoarthritis and assist them in decision-making.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04105478 . Registered on 25 September 2019.

Cementless curved short stem shoulder prostheses with a proximal porous coating: ingrowth properties at 2-5 years of radiological follow-up with clinical correlation

BACKGROUND

Little is known about the way the newest generation of stems integrate into the proximal humerus and their effect on the surrounding bone. Factors that may influence ingrowth have not been investigated.

METHODS

A consecutive cohort study was conducted that examined 74 anatomical, reverse, or pyrocarbon hemiprostheses, using a curved modular short stem with a proximal porous coating 2-5 years postoperatively (mean 35 months). X-rays were reviewed by 2 examiners independently. Bone loss was scored with 1 point per zone with partial and 2 points per zone with complete resorption (10 zones). The Constant score was used for clinical correlation. Multiple linear regression was employed to investigate correlations between variables.

RESULTS

No subsidence or shift of the stems occurred. Two of 74 patients showed 1 zone of periprosthetic lucency of 1 mm. The filling ratio averaged 0.54 (range: 0.36-0.75). Thirty patients (40.5%) displayed bone resorption, first seen at 16.6 months (range: 3-40 months), commonly in zones 1 and 5. A total of 22 patients had ≥1 zone with partial resorption, and 8 (10.8%) developed full thickness resorption after 32 (range: 10-49) months.One new finding was that female sex and older age accounted for 51% of the variation of the filling ratio. A high filling ratio, especially when >0.55, correlated with bone resorption (P < .001). Age, sex, and prosthesis type did not directly predict bone resorption. Bony sclerosis correlated with a high filling ratio (P = .019) and thereby indirectly with resorption. A direct correlation between sclerosis and resorption was narrowly insignificant (P = .058) once correcting for the filling ratio. Reverse shoulder prosthesis had a higher filling ratio than total shoulder prosthesis patients (P < .001), resulting indirectly in more bone resorption. The preoperative diagnosis did not significantly correlate with the filling ratio (P = .59) or the resorption score (P = .69). A varus or valgus alignment did not predict resorption (P = .21) or the formation of sclerotic lines (P = .93). Bone loss did not correlate with clinical results.

CONCLUSIONS

These short stems are firmly anchored 2-5 years postoperatively. However, significant bone loss, linked to a high filling ratio (>0.55), is observed proximally around these stems. The development of sclerotic lines around the stem indicates oversizing. Other factors were not found to have a significant effect on stem ingrowth. The implantation of stems with a large filling ratio is more common in older females and in patients receiving reverse shoulder prosthesis. Autologous impaction bone grafting could downsize the required stem. If adequate hold is not afforded by a suitably small stem, cementation is advisable.

[Periprosthetic humeral fractures: from osteosynthesis to prosthetic replacement]

OBJECTIVE

Stabilization of the humeral shaft and the restoration of shoulder function dependent on the osseous integrity of the prosthetic stem component.

INDICATIONS

In cases of a stable prosthesis stem, an isolated plate osteosynthesis is possible. Prosthesis stem replacement is indicated in cases of a loose stem. With sufficient bone stock of the proximal humeral segment, a change to a shorter humeral shaft component with subsequent plate fixation of the fracture is possible. If the bone stock is poor, conversion to a long revision stem is necessary.

CONTRAINDICATIONS

Inoperability of the patient due to serious comorbidities. Advanced age and low demands on shoulder function are relative contraindications for complex prosthesis replacements.

SURGICAL TECHNIQUE

Plate osteosynthesis can be done through an anterior or posterior approach, stem replacement only from anterior deltopectoral approach. When changing humeral shaft components, the loose shaft and all cement residues are removed, the fracture is reduced and, if possible, a shorter shaft is implanted with subsequent plate osteosynthesis of the fracture. When changing to a long revision stem, additional osteosynthesis with cerclages wires is usually sufficient. In case of poor bone stock, an additive autologous or allogenic bone grafting can be performed. An instable anatomical prosthesis with poor shoulder function may require conversion to an inverse prosthesis.

POSTOPERATIVE MANAGEMENT

In cases of an isolated plate osteosynthesis with an otherwise stable prosthesis, immediate active rehabilitation of the upper limb is advocated. When a prosthesis replacement and conversion to an inverse prosthesis is performed the shoulder is immobilized in 30° abduction for 6 weeks. Passive and after 3 weeks active-assistive shoulder movement up to 90° abduction and flexion is allowed.

RESULTS

In 40 patients with a periprosthetic humeral fracture, an isolated plate osteosynthesis was performed in 30 cases and a prosthesis replacement in 10 cases. Complications included 3 infections and 3 temporary radial nerve palsies. Revisions due to pseudarthrosis were necessary in 2 cases.

No correlation between radiolucency and biomechanical stability of keeled and pegged glenoid components

Background

The purpose of this study was to examine biomechanical properties and the degree of radiolucency of two cemented basic glenoid designs for total shoulder arthroplasty. Our hypothesis was that a component with increased micro-motion in the laboratory at time zero would also exhibit a greater amount of radiolucency in patients at a minimum of 2 years post total shoulder arthroplasty.

Methods

Thirty cadaveric shoulders were divided into 2 groups (keel vs. peg). The glenoid components were first loaded with a single axial eccentric force of 196 N in all orientations and then with a transversal load of 49 N to simulate in vivo loads with abduction. Displacement of the glenoid component was determined with four different linear variable-differential transducers. In the second phase, 56 antero-posterior x-rays of 52 patients with either the same keeled (n = 24) or pegged (n = 32) glenoid component with a minimum of 24 months follow-up were evaluated for radiolucency.

Results

Biomechanically the pegged glenoid showed a significant increase in micro-motion during eccentric axial loading as well as during combined loading in the anterior, posterior, and inferior position as compared to the keeled glenoid (p < 0.05). In contrast all results were significant with greater radiolucency for the keeled glenoid component (p = 0.001).

Conclusion

While the pegged component exhibited a greater amount of micro-motion during biomechanical testing, radiolucency was greater in patients with a keeled component. These findings provide support for both components from different perspectives and highlight the need for well-constructed studies to determine whether glenoid design has an effect on clinical outcome, because influences are multifactorial and biomechanical forces may not recreate forces seen in vivo.

Computed tomography morphological analysis of the scapula and its implications in shoulder arthroplasty

BACKGROUND

Healthy shoulder morphology is still unclear. Since bone morphology influences prosthetic features, this is relevant for glenohumeral joint reconstruction. The objective of this study was to assess the normal values of glenoid version, maximum width, base width and vault depth on computed tomography scans.

METHODS

Axial cut CT scans of 1072 healthy glenoids were retrospectively reviewed. Values of glenoid version, maximum glenoid width, glenoid base width and glenoid vault depth were measured by two different observers. Differences were determined between genders, and reproducibility and interrater reliability assessed.

RESULTS

Glenoid version was 37.71° ± 10.75°, range -6.20° to 71.30°; maximum glenoid width was 26.06 ± 3.27 mm, range 15.40-36.90 mm; glenoid base width was 16.59 ± 2.61 mm, range 8.90-25.40 mm; glenoid vault depth was 9.72 ± 1.62 mm, range 4.70-15.90 mm. All measurements except for glenoid version were significantly higher in males than in females. Reproducibility was good for every measurement, except glenoid vault depth.

CONCLUSION

We found differences in maximum glenoid width, base width and vault depth by gender in a large sample. Glenoid components' maximum width was defined, as was reaming extension and orientation, the space available for implantation of the glenoid component, placement of pegs or keels in anatomic prostheses and the target for glenoid screws in inverted prostheses.

LEVEL OF EVIDENCE

II.

Short humeral stem in total shoulder arthroplasty does not jeopardize primary implant stability

Background

The trend of the modern humeral components in total shoulder arthroplasty is toward shorter and shorter humeral stems. However, the question remains whether short uncemented stems can provide the same implant stability as long stems. This study aimed to evaluate and compare the torsional primary stability and the pull-out extraction force of both a long and a short version of the same stem.

Materials and methods

Ten humeral components (five long stems and five short stems) were press-fitted into ten synthetic composite humeri. A torsional load was applied to generate the most critical loading condition. The specimens were loaded with 100 cycles between 2 Nm and 10 Nm, at 1 Hz. A 3D Digital Image Correlation system was used to measure the relative displacement between the prosthesis and the host bone during the test. After completing the torsional test, the pull-out force was measured. Differences between the long and short stem on the biomechanical parameters (permanent migrations, inducible micromotion, and extraction force) were tested with the nonparametric Mann-Whitney test (P < .05).

Results

The main rotational inducible micromotion was around the craniocaudal axis. No significant differences were found between the rotational permanent migrations of the long and short stem around the craniocaudal (P = .421), anteroposterior (P = .841), and mediolateral axes (P = .452). No significant differences were found between the rotational inducible micromotions of the long and short stem around the craniocaudal (P = .222), anteroposterior (P = .420), and mediolateral axes (P = .655). No significant differences were found between the permanent translations of the long and short stem along the craniocaudal (P = .341), anteroposterior (P = .420), and mediolateral (P = .429) directions. No significant differences were found between the translations of the long and short stem in terms of inducible translation in the craniocaudal (P = .547), anteroposterior (P = .999), and mediolateral axes (P = .285). Similar extraction force (P = .35) was found.

Discussion and Conclusion

No statistically significant difference was found between the long-stem and short-stem implants. These results show that short uncemented stems can provide adequate primary mechanical stability. As the long-stem version of this stem is already clinically used, the present findings suggest that the short version can be reasonably expected to deliver similar outcomes in terms of implant stability.

[Irreparable rotator cuff tear-reverse shoulder arthroplasty and alternative procedures]

Irreparable rotator cuff tears represent a significant everyday clinical challenge. A high degree of tendon retraction and muscle degeneration means that a direct reconstruction is impossible. Patients often suffer from pain and pseudoparalysis. In older patients this can reliably be resolved by the implantation of a semiconstrained inverse shoulder prosthesis; however, for younger patients joint-preserving techniques should be employed. Furthermore, for frail older patients who may not be suitable for a joint replacement operation, alternative treatment strategies are required. Management options include physiotherapy and pain relieving or reconstructive operations. Minimally invasive arthroscopic treatment approaches can lead to pain relief and slight functional improvements in selected patients; however, to restore the active movement of the joint a partial cuff repair, augmentation with a graft or replacement with muscle transfer is necessary. This article presents the various treatment options and the results reported in the literature. Through this a treatment algorithm is suggested in order to facilitate management decisions.

Single-stage revision for total shoulder arthroplasty infection. Results at a minimum 2 years follow-up

INTRODUCTION

Similar to the management of periprosthetic joint infections of the lower limb, one-stage revision in total shoulder arthroplasty (TSA) infections is an option that has been highlighted in scientific publications since the early 2010s. However, there are only a few studies which validate this treatment and determine its scope of application in relation to two-stage treatment.

HYPOTHESIS

Single-stage revision for infected TSA is a reliable treatment allowing good infection control and satisfactory functional results.

METHODS

This single-center retrospective series of 34 consecutive patients operated on between 2014 and 2020 for a one-stage prosthetic revision was evaluated at a minimum of 2 years of follow-up. All of the patients included underwent revision shoulder arthroplasty during this period with the diagnosis of infection confirmed by microbiological analysis of surgical samples. Patients who did not benefit from a bipolar revision were excluded. All patients were followed at least 2 years after the intervention. Clinically suspected recurrence of infection was confirmed by a periprosthetic sample under radiographic guidance. Functional clinical outcomes as well as mechanical complications were also reported.

RESULTS

The average follow-up was 40.4 months (24-102±21.6). A septic recurrence was observed in three patients (8.8%). A mechanical complication was present in four patients (14.7%), and three (11.8%) required at least one surgical revision. The mean Constant-Murley score at the last follow-up was 49 (42-57±21.83).

DISCUSSION

Single-stage revision for shoulder periprosthetic joint infection results in a success rate of 91.2% with satisfactory functional results after more than 2 years of follow-up.

LEVEL OF EVIDENCE

IV; retrospective study.

[Periprosthetic fractures of the shoulder girdle]

Periprosthetic fractures of the shoulder girdle will increasingly become part of routine clinical practice due to rising numbers of joint replacements and the demographic changes. Diagnostically, the status of the rotator cuff, bed of the implant (stable or loose), type of shoulder arthroplasty as well as exclusion of joint infections are crucial for therapeutic decision-making. Novel imaging tools, such as dual-energy computed tomography provide improved preoperative planning options. The unified classification system describes the fracture location, stability of the prosthesis and quality of the bone. While nonoperative treatment is reserved for patients with severe pre-existing conditions and nondisplaced fractures, the standard treatment of fractures with a stable bed include fixation with cerclage wiring and angular stable plates. Modern implant systems with variable angle screw holes, attachment plates and hinges enable secure fixation around the stem. In cases of a loose stem revision arthroplasty is necessary. There are currently only a limited number of clinical studies with only few patients that analyzed clinical and radiological results. Thus, increased research efforts are indispensable in order to compare treatment options and improve treatment quality.

Risk factors of instability following reverse total shoulder arthroplasty in patients with no history of shoulder surgery

Introduction

As its indications expand, reverse total shoulder arthroplasty (rTSA) utilization continues to increase. Though relatively uncommon, instability following rTSA can be associated with significant morbidity and need for subsequent revision and treatment. This case control study aims to characterize factors leading to instability after rTSA, especially in those with no previous shoulder surgery.

Methods

194 rTSAs performed within the study period with appropriate operative indications and follow-up were included. Risk factors used in analysis included age, gender, BMI, ASA class, Charlson comorbidity index (CCI), glenosphere, tray, and liner size. Data was analyzed using a hierarchical binary logistical regression to create a predictive model for instability.

Results

Seven patients sustained a post-operative dislocation. Mean time to dislocation was 60.4 weeks. Five required open reduction with placement of either a larger humeral tray or polyethylene spacer. One required open reduction with osteophyte removal, and one was converted to a resection arthroplasty. Dislocators were more likely to have a larger BMI (p = 0.002), higher ASA classification (p = 0.09), and larger liner size (p = 0.01).

Conclusion

This study demonstrates a large series of patients successfully treated with rTSA. Dislocations were an uncommon complication, but were clearly associated with higher patient BMI, ASA classification, and increased liner size.

Rehabilitation following shoulder arthroplasty: a survey of current clinical practice patterns of Italian physiotherapists

BACKGROUND

The incidence of Total Shoulder Arthroplasty (TSA) and Reverse Total Shoulder Arthroplasty (RTSA) is constantly increasing. As a result, the interest in post-surgical rehabilitation has grown, since it is crucial in order to achieve full recovery and successful outcomes. The first aim of this study is to investigate the Italian physiotherapists (PTs) clinical practice in the management of patients with TSA and RTSA and to compare it with the best evidence available in the literature. The second purpose of this study is to assess any existing difference between the survey answers and the different sample subgroups.

MATERIALS AND METHODS

This cross-sectional observation study was designed following the CHERRIES checklist and the STROBE guidelines. A 4-sections survey with a total of 30 questions was developed for investigating post-surgery rehabilitation management in patient with TSA and RTSA. The survey was sent to Italian PTs from December 2020 until February 2021.

RESULTS

Six-hundred and seven PTs completed the survey regarding both TSA and RTSA; 43.5% of participants (n = 264/607) stated that TSA is more likely to dislocate during abduction and external rotation. Regarding reverse prosthesis, 53.5% (n = 325/607) affirmed RTSA is more likely to dislocate during internal rotation, adduction and extension. In order to recover passive Range of Motion (pROM), 62.1% (n = 377/607) of participants reported that they gain anterior flexion, abduction, internal rotation, external rotation up to 30°, with full pROM in all directions granted at 6-12 weeks. Regarding the active ROM (aROM), 44.2% (n = 268/607) of participants stated that they use active-assisted procedures within a range under 90° of elevation and abduction at 3-4 weeks and higher than 90° at 6-12 weeks, with full recovery at a 3-month mark. Sixty-five point seven percent of the sample (n = 399/607) declared that, during the rehabilitation of patients with TSA, they tend to focus on strengthening the scapular and rotator cuff muscles, deltoid, biceps and triceps. Conversely, 68.0% (n = 413/607) of participants stated that, for the rehabilitation of patients with RTSA, they preferably focus on strengthening the periscapular and deltoid muscles. Finally, 33.1% (n = 201/607) of participants indicated the instability of the glenoid prosthetic component as the most frequent complication in patients with TSA, while 42.5% (n = 258/607) of PTs identified scapular neck erosion as the most frequent post-RTSA surgery complication.

CONCLUSIONS

The clinical practice of Italian PTs effectively reflects the indications of the literature as far as the strengthening of the main muscle groups and the prevention of movements, which may result in a dislocation, are concerned. Some differences emerged in the clinical practice of Italian PTs, regarding the restoration of active and passive movement, the starting and progression of muscle strengthening and the return to sport (RTS). These differences are actually quite representative of the current knowledge in post-surgical rehabilitation for shoulder prosthesis in the rehabilitation field.

LEVEL OF EVIDENCE

V.