Acromion fractures after reverse shoulder arthroplasty occur in predictable clusters

BACKGROUND

Acromion and scapular spine fractures (ASFs) following reverse total shoulder arthroplasty (RSA) have been reported at a rate of 3.9%. The location of the fracture has been shown to be an important factor in determining the outcomes of nonoperative treatment, with medial fractures having worse outcomes than lateral fractures. As the debate between operative and nonoperative treatment continues, a more precise understanding of the location of the fracture is necessary for effective management. The purpose of this study was to use 3-dimensional computed tomography (CT) reconstruction to characterize the exact location of ASFs after RSA.

METHODS

A retrospective review of 2 separate institutional shoulder and elbow repositories was performed. Patients with post-RSA ASFs documented by post-fracture CT scans were included. The query identified 48 patients who sustained postoperative ASFs after RSA between July 2008 and September 2021. CT scans of patients with ASFs were segmented using Mimics software. Eight patients were excluded because of poor image quality. Each bone model was manipulated using 3-Matic Medical software to align the individual scapula with an idealized bone model to create a view of scapular fracture locations on a normalized bone model. This model was used to classify the fractures using the modified Levy classification.

RESULTS

The study cohort consisted of 40 patients with a diagnosis of postoperative ASF after RSA. The median age at the time of surgery was 76 years (interquartile range, 73-79 years). The cohort comprised 32 women (80%) and 8 men (20%), with a median body mass index of 27.8. Only 10 patients (25%) had a previous diagnosis of osteoporosis and 6 (13%) had a diagnosis of inflammatory arthritis; 53% of patients underwent RSA owing to rotator cuff tear arthropathy. The distribution of fracture locations was similar within the cohort. However, lateral fractures were slightly more prevalent. The most common fracture location was the type I zone, with 12 fracture lines (29%). There were 11 fracture lines (26%) in the type IIa zone, 10 (23%) in the type IIb zone, 0 in the type IIc zone, and 9 (21%) in the type III zone.

CONCLUSION

ASFs after RSA occur in 4 predictable clusters. No fractures appeared to distinctly cluster in the type IIc zone, which may not represent a true fracture zone. Understanding the distribution of these fractures will help to enable the future design of implants and devices to stabilize the fractures that require fixation.

Covariations between scapular shape and bone density in B-glenoids: A statistical shape and density modeling-approach

B-type glenoids are characterized by posterior humeral head migration and/or bony-erosion-induced glenoid retroversion. Patients with this type of osteoarthritic glenoids are known to be at increased risk of glenoid component loosening after anatomic total shoulder arthroplasty (aTSA). One of the main challenges in B glenoid surgical planning is to find a balance between correcting the bony shape and maintaining the quality of the bone support. This study aims to systematically quantify variabilities in terms of scapular morphology and bone mineral density in patients with B glenoids and to identify patterns of covariation between these two features. Using computed tomography scan images of 62 patients, three-dimensional scapular surface models were constructed. Rigid and nonrigid surface registration of the scapular surfaces, followed by volumetric registration and material mapping, enabled us to develop statistical shape model (SSM) and statistical density model (SDM). Partial least square correlation (PLSC) was used to identify patterns of covariation. The developed SSM and SDM represented 85.9% and 56.6% of variabilities in terms of scapular morphology and bone density, respectively. PLSC identified four modes of covariation, explaining 66.0% of the correlation between these two variations. Covariation of posterior-inferior glenoid erosion with posterior sclerotic bone formation in association with reduction of bone density in the anterior and central part of the glenoid was detected as the primary mode of covariation. Identification of these asymmetrical distribution of bone density can inform us about possible reasons behind glenoid component loosening in B glenoids and surgical guidelines in terms of the compromise between bony shape correction and bone support quality.

In silico analysis of rib force distribution in postscapulothoracic arthrodesis model

Scapulothoracic arthrodesis (STA) is carried out by fixing the scapula to thoracic ribs which in turn allows the patient suffering from Facioscapulohumeral Muscular Dystrophy to carry out shoulder-joint dependent activities of daily living. A biomechanical analysis of this procedure has not been conducted in the literature and, for the first time, this study investigates the finite element calculated glenohumeral-applied load distributions on ribs by creating a post-STA model. Three loading directions on the glenohumeral joint are designated: anterior-posterior, superior-inferior, and lateral-medial. Reaction forces on the ribs are calculated based on the glenoid force percent. Simulations are repeated by removing a singular rib contact to observe the change in force distributions in the case of missing levels or failed bonding as well as the impact of clavicle osteotomy. Total load distribution is observed highest at T2 followed by T3 and T6. In the T2 missing scenario, total loads on T3 and T4 increase. In the T4 missing case, the most affected level is T3. In the T6 missing scenario, total loads on T5 and T7 increase. In the clavicular osteotomy scenario, all levels' loads increase; the highest is recorded in T7 by 460%, followed by T5, T4, T2, T6, and T3. While all levels contribute to fixation strength, T2 is subjected to the highest loads, and, in the missing level scenarios, the loads are tolerated sufficiently by the remaining levels. Missing T4 scenario has the least effect on the system, which is interpreted as potentially the only skippable level of fixation. Clavicular osteotomy has the highest effect on the arthrodesis site.

Both angled bony-increased offset and metal-augmented baseplates provide satisfactory bone incorporation to the glenoid in reverse total shoulder arthroplasty: a radiographic evaluation using tomosynthesis

BACKGROUND

Angled bony-increased offset and metal-augmented baseplate have recently been used to achieve neutral to inferior inclination of the glenoid implant. Nonetheless, bone incorporation is difficult to evaluate using computed tomography or other conventional methods owing to the presence of metal artifacts; therefore, whether bone incorporation between the grafted bone and glenoid or between the graft and baseplate implant can be achieved remains unclear. Several studies have reported the effectiveness of tomosynthesis in reducing metal artifacts for the evaluation of implant loosening, bone resorption, and spot welds. We aimed to evaluate and compare the bone incorporation rates between angled bony-increased offset and metal-augmented implants using tomosynthesis with metal artifact reduction technology. We hypothesized that a high bone incorporation rate would be obtained with angled bony-increased offset and a metal-augmented baseplate.

METHODS

A total of 52 patients who underwent reverse total shoulder arthroplasty (TSA) with angled bony-increased offset and 42 patients who underwent reverse total shoulder arthroplasty with metal-augmented baseplate were assessed and followed up for a minimum of 2 years. The bone incorporation and implant loosening rates were compared between the 2 groups, and the sites of spot welds and trabeculation were recorded according to zones. Bone incorporation between the bone and prosthesis was defined as a confirmation of spot welds connecting the porous area and bone in more than three zones. Bone incorporation between the native bone and grafted bone was defined as an observation of trabeculation. Glenoid loosening was defined as the presence of at least 1 mm radiolucency around the prosthesis in more than 2 zones.

RESULTS

Both the angled bony-increased offset and metal-augmented baseplate groups achieved sufficient bone incorporation rates (98% [51/52 cases] vs. 100% [42/42 cases], P = 1.0) and low implant loosening rates (2% [1/52 cases] vs. 0% [0/42 cases], P = 1.0). Spot welds and trabeculation were likely to be confirmed in the lower parts of the glenoid.

CONCLUSION

The two groups did not show any significant differences regarding bone incorporation rates. Considering the complexity of performing the procedure with angled bony-increased offset, the use of a metal-augmented baseplate can serve as an alternative treatment to avoid superior inclination in reverse total shoulder arthroplasty.

Lateralising reverse shoulder arthroplasty using bony increased offset (BIO-RSA) or increasing glenoid component diameter: comparison of clinical, radiographic and patient reported outcomes in a matched cohort

BACKGROUND

This study aims to compare the range of motion (ROM) of reverse shoulder arthroplasty lateralised by bony increased offset (BIO-RSA) using a standard 38-mm (mm) component to regular reverse shoulder arthroplasty (RSA) lateralised by using a 42-mm glenoid component. The secondary aims are to compare patient-reported and radiographic outcomes between the two groups.

MATERIALS AND METHODS

All patients with a BIO-RSA and size 38 glenosphere were retrospectively identified and matched to patients with a regular RSA and size 42 glenosphere. Matched patients were invited for a follow-up visit. ROM was assessed as well as radiographic outcomes (lateralisation, distalisation, inferior overhang, scapular notching, heterotopic bone formation, radiolucency, stress shielding, bone graft healing and viability and complications) and patient-reported outcomes (subjective shoulder value, Constant score, American Shoulder and Elbow Surgeons, activities of daily living which require internal rotation, activities of daily living which require external rotation and a visual analogue scale for pain). Outcomes were compared between the two groups.

RESULTS

In total, 38 BIO-RSAs with a size 38 glenosphere were matched to 38 regular RSAs with a size 42 glenosphere. Of the 76 matched patients, 74 could be contacted and 70 (95%) were included. At the final follow-up, there were no differences between the two groups in ROM, patient-reported outcomes or radiographic outcomes (p > 0.485).

CONCLUSIONS

Using a larger glenosphere is a feasible alternative to BIO-RSA for lateralising RSA, providing comparable ROM, patient-reported and radiographic results, while potentially decreasing costs, operative time and complication rates.

LEVEL OF EVIDENCE III

Premorbid glenoid anatomy reconstruction from contralateral shoulder 3-dimensional measurements: a computed tomography scan analysis of 260 shoulders

BACKGROUND

Total shoulder arthroplasty (TSA) aims to reconstruct the premorbid anatomy of a pathologic shoulder. A healthy contralateral shoulder could be useful as a template in planning TSA. The symmetry between the left and right shoulders in healthy patients remains to be proved. The purpose of this study was to compare the 3-dimensional anatomy of the glenoid between sides in a healthy population.

METHODS

A multinational computed tomography scan database was retrospectively reviewed for all healthy bilateral shoulders in patients aged between 18 and 50 years. One hundred thirty pairs of healthy shoulder computed tomography scans were analyzed, and glenoid version, inclination, width, and height, as well as glenoid lateral offset and scapula lateral offset, were measured. All anatomic measures were computed with Blueprint, validated 3-dimensional planning software. The intraclass correlation coefficient was determined for each measure between left and right shoulders. The minimal detectable change (MDC) was calculated using the following formula: MDC=2×1.96×Standarderrorofmeasurement.

RESULTS

The comparison between 130 pairs of healthy scapulae showed statistically significant differences in absolute values between right and left glenoid version (-5.3° vs. -4.6°, P < .01), inclination (8.4° vs. 9.3°, P < .01), and width (25.6 mm vs. 25.4 mm, P < .01), as well as scapula offset (105.8 mm vs. 106.2 mm, P < .01). Glenoid height was comparable between right and left shoulders (33.3 mm vs. 33.3 mm, P = .9). The differences between the means were always inferior to the MDC regarding glenoid version, inclination, height, and width, as well as scapula offset. Very strong intraclass correlation coefficients between the left and right shoulders were found for all evaluated paired measures.

CONCLUSION

Healthy contralateral scapulae are highly reliable to predict inclination, height, width, and scapula offset and are reliable to predict version of a given scapula. Paired right and left scapulae were not statistically symmetrical regarding mean glenoid version, inclination, and width, as well as scapula offset. Nevertheless, the reported differences were not higher than the MDC for this cohort, confirming that healthy contralateral shoulders can be a useful template in TSA preoperative planning.

Inlay structure can improve bone graft stability in the Bristow procedure

BACKGROUND

Compared with the Latarjet procedure, the Bristow procedure has a lower screw-related complication rate but poor bone healing. A modified Inlay Bristow procedure has been reported to significantly improve the bone healing rate, but the biomechanical mechanism is unclear. The aim of this study was to evaluate the biomechanical stability of the bone graft between a modified Inlay Bristow procedure and the classic Bristow procedure.

METHODS

Sixteen left scapula models (Sawbones, Composite Scapula, and fourth generation) were randomly divided into 2 groups (8:8). The bone graft in the first group was fixed with a 3.5 mm screw using the Inlay structure. The bone graft in the second group was fixed with a 3.5 mm screw via the traditional method. The maximum cyclic displacement, ultimate failure load and stiffness were evaluated biomechanically. The failure type was recorded for each model.

RESULTS

Cyclic loading tests demonstrated that the maximum cyclic displacement of the Inlay procedure was significantly smaller (P = .001) than that of the classic procedure. The Inlay Bristow technique resulted in a significantly higher (P = .024) ultimate failure load than the classic Bristow technique. The stiffness of the classic group was 19.17 ± 4.01 N/mm and that of the inlay group was 22.34 ± 5.35 N/mm (P = .232). Failure was mainly due to bone graft fractures through the drill hole or glenoid bone fractures.

CONCLUSION

Inlay Bristow fixation of the bone graft in a Sawbones model provides significantly stronger fixation and better time point zero stability than classic Bristow fixation, suggesting a higher likelihood of graft union.

3D-printed glenoid implant reconstruction, after partial scapulectomy for malignant tumors: a case series

PURPOSE

Glenoid tumors are extremely rare, and reconstruction remains very challenging. The aim of this study is to present the clinical and functional outcomes, of a new glenoid reconstruction method using 3-dimensional-printed implant.

METHODS

Four patients with primary glenoid tumors underwent reconstruction using 3-dimensional-printed glenoid implant linked with reverse shoulder arthroplasty. We retrospectively reviewed the clinical and functional outcome, using MSTS and DASH score, as well as complications' rate.

RESULTS

Wide excision was achieved in all patients. No local recurrence or distant metastasis was diagnosed at the follow-up period. The mean MSTS score was 80.5%, and DASH score was 15.2%. According to Hendersons' classification, there were no postoperative complications.

CONCLUSION

The use of 3-dimensional-printed implants, can be a very reliable solution with satisfying clinical and functional outcomes for reconstruction, in patients with musculoskeletal malignancies of the glenoid. Level of evidence IV Treatment Study.

Risk of suprascapular nerve injury in open Trillat procedure: an anatomical study

PURPOSE

The open Trillat Procedure described to treat recurrent shoulder instability, has a renewed interest with the advent of arthroscopy. The suprascapular nerve (SSN) is theoretically at risk during the drilling of the scapula near the spinoglenoid notch. The purpose of this study was to assess the relationship between the screw securing the coracoid transfer and the SSN during open Trillat Procedure and define a safe zone for the SSN.

METHODS

In this anatomical study, an open Trillat Procedure was performed on ten shoulders specimens. The coracoid was fixed by a screw after partial osteotomy and antero-posterior drilling of the scapular neck. The SSN was dissected with identification of the screw. We measured the distances SSN-screw (distance 1) and SSN-glenoid rim (distance 2). In axial plane, we measured the angles between the glenoid plane and the screw (α angle) and between the glenoid plane and the SSN (β angle).

RESULTS

The mean distance SSN-screw was 8.8 mm +/-5.4 (0-15). Mean α angle was 11°+/-2.4 (8-15). Mean β angle was 22°+/-6.7 (12-30). No macroscopic lesion of the SSN was recorded but in 20% (2 cases), the screw was in contact with the nerve. In both cases, the β angle was measured at 12°.

CONCLUSION

During the open Trillat Procedure, the SSN can be injured due to its anatomical location. Placement of the screw should be within 10° of the glenoid plane to minimize the risk of SSN injury and could require the use of a specific guide or arthroscopic-assisted surgery.

Primary bone graft stability after Latarjet surgery: biomechanical evaluation of a fixation technique with metal-free all-suture cerclage vs. cortical screws

BACKGROUND

To reduce hardware-related complications in coracoid graft fixation to the anterior aspect of the glenoid, a metal-free Latarjet technique was recently introduced. The aim of this study was to compare the primary stability of a classic Latarjet procedure with 2 metal screws to a novel metal-free, all-suture cerclage method. It is hypothesized that fixation of the coracoid graft with 2 malleolar screws will provide higher primary stability compared with an all-suture cerclage technique.

METHODS

This biomechanical in vitro study was conducted on 12 fresh-frozen cadaveric shoulders (6 matched pairs) with a mean donor age of 80 years (range, 67-89 years). Coracoid graft fixation was performed using a recently introduced all-suture cerclage technique (group A) or a classic Latarjet technique with two 4.5-mm malleolar screws (group B). The conjoint tendon was loaded with a static force of 10 N to simulate the sling effect. Graft loading with a probe head consisted of 6 ascending load levels (10-50 N, 10-100 N, 10-150 N, 10-200 N, 10-250 N, and 10-300 N) with 100 cycles each at 1 Hz. Relative motion of the bone graft to the glenoid was measured using an optic 3-dimensional system.

RESULTS

While loading the conjoint tendon with 10 N, no difference in mean displacement of the bone-graft was found between both groups (P = .144). During cyclic loading, a significant difference in relative displacement for both groups was already detected in load level 1 (group A: 2398.8 μm vs. group B: 125.7 μm; P = .024), and this trend continued with the following load levels (P < .05).

DISCUSSION AND CONCLUSION

The study demonstrated that the innovative metal-free, all-suture cerclage fixation technique results in higher micromotion than the classic coracoid graft fixation with 2 malleolar screws. According to the present biomechanical investigation, shoulders treated with a metal-free all-suture cerclage technique might need adapted rehabilitation protocols to protect the construct and allow for graft healing.

Revision of failed reverse total shoulder arthroplasty with reverse: short-term clinical outcomes

BACKGROUND

The prevalence of failed reverse total shoulder arthroplasty (rTSA) is increasing. This can often present a challenging clinical situation with substantial bone loss and limited reconstruction options. This study reports a single tertiary referral center's experience with revision of failed rTSA managed with revision rTSA of bone-interfacing components.

METHODS

After institutional review board approval, all revision shoulder arthroplasty cases performed at a single institution between 2012 and 2020 were reviewed. Cases in which rTSA was revised to a new rTSA construct with revision of at least 1 bone-interfacing implant (humeral stem and/or baseplate) with a minimum 2-year follow-up were identified. Characteristics of revision cases-including indications, bony stock, revised components, and use of bone graft-were collected. All patients were contacted for patient-reported outcome measures at a minimum of 2 years after surgery. In addition, the incidence and indication for any reoperation after revision were determined.

RESULTS

Thirty-three patients with an average age of 66 years (range: 46-82 years), with 19 (58%) being female, met the inclusion criteria and had a mean follow-up of 4.2 years (range: 2-8 years). The most common indication for revision rTSA included humeral component loosening (33%; 11/33), baseplate loosening (27%; 9/33), and instability (21%; 7/33). Prerevision infectious workup demonstrated no cases of periprosthetic shoulder infection. Thirteen cases had massive bone loss-5 treated with humeral allograft prosthetic composite, 5 with glenoid bone grafting, and 3 with custom glenoid implant. In total, 10 of 33 cases (30%) required reoperation at a mean of 13 months (range: 1-44 months) for instability (4), humeral loosening (2), infection (1), baseplate loosening (1), or periprosthetic fracture (1). The reoperation rate for patients with revised baseplates only, humerus only, or combined was 23% (3/13), 28% (5/18), and 27% (3/11), respectively. Overall, the visual analog scale pain score improved from 6.5 preoperatively to 2.0 (P < .001), and the American Shoulder and Elbow Surgeons score improved from 30.7 to 67.5 (P < .001). However, the postoperative Single Assessment Numeric Evaluation score averaged only 51.2% (range: 2-100%).

CONCLUSION

This study demonstrates that failed rTSA can be salvaged with a revision rTSA. However, patient expectations for functional improvements should be tempered, and a high reoperation rate should be expected.

The latissimus dorsi creates a dynamic track for the inferior angle of the scapula during arm abduction in humans

BACKGROUND

The importance of several scapulothoracic muscles, including trapezius and serratus anterior, in maintaining physiological scapula kinematics has been highlighted in the past. However, the relationship between the scapula and the latissimus dorsi muscle remains unclear. Our clinical surgical observation is that the latissimus dorsi does not directly attach but rather runs superficial to the inferior angle of the scapula. Based on this observation, we hypothesise that the latissimus dorsi creates a dynamic track on which the scapula glides under the muscle belly during elevation of the arm, creating the latissimus-scapula overlap (LSO).

METHODS

All consecutive patients who had a whole-body computed tomography scan (CT) in case of polytrauma evaluation between 2018 and 2021, with complete depiction of the scapula and latissimus dorsi muscle, were analysed. 150 shoulders in 90 patients with arms up were matched according to their age (within five years), gender, and affected side with 150 shoulders in 88 patients with arms down. Patients with pathologies of the upper extremities or thorax that potentially could alter LSO measurements were excluded. LSO was calculated as a ratio of the measured area of the latissimus dorsi projection on the scapula and the total scapula area.

RESULTS

The mean age of the 178 patients (48 females; 13 males) was 60 years. The arms-up group showed a significantly higher LSO than the arms-down group (19.9 ± 6.3% vs. 2.7 ± 2.2%; p < 0.0001). In the arms-up group, approximately one fifth of the scapula was overlapped inferiorly by the muscle belly of the latissimus dorsi, contrary to the almost non-existing LSO in the arms-down group.

CONCLUSION

With arms up, humans show a significantly higher LSO in comparison to arms down indicating that the latissimus dorsi indeed creates a dynamic track on which the scapula is forced to travel during abduction of the arm. This finding of increased LSO during the elevation of the arm warrants further consideration of the role of the latissimus dorsi in scapula kinematics and potentially scapular dyskinesis.

LEVEL OF EVIDENCE

Level two diagnostic study.

Posterior deltoid-sparing approach for displaced inferior or posterior glenoid fossa fractures: technical note and case series

Scapular surgery has usually been performed through the posterior Judet approach. This approach allows access to the entire posterior scapular body, but causes significant soft tissue damage and detaches the deltoid muscle. To date, there has been no clinical study of a deltoid-preserving approach to access the joint for displaced postero-inferior glenoid fractures (Ideberg type II or Ib). We describe an easy and less invasive approach to the postero-inferior glenoid fossa.

Treatment options and outcomes for delayed scapular anatomical neck fractures: a case report and review of the literature

INTRODUCTION

Scapular anatomical neck fractures are among the most infrequent shoulder girdle fractures. Only seven radiologically confirmed cases of scapular anatomical neck fractures have been documented in the literature to date, of which only one case underwent delayed surgery.

CASE PRESENTATION

A 34-year-old male Persian patient with morbid obesity was diagnosed with a scapula anatomical neck fracture after a motor vehicle collision. The radiographic assessment of the patient indicated an increase in the scapular glenopolar angle (73.9°). Due to concurrent chest and head injuries, surgical intervention was deferred until 6 weeks following the injury. The posterolateral limited Dupont-Evrard approach was used because of the patient's extremely high body mass index. Two plates were utilized to achieve stable fixation of the glenoid neck fracture. Following a 1 year follow-up period, complete fracture union was successfully attained, resulting in a constant score of 79.

CONCLUSIONS

The most accurate radiographic indicators of these fractures are a superior fracture line located laterally to the coracoid process, a small inferior spike, and an elevated glenopolar angle. The only tendon attached to the glenoid is the long head of the triceps, making these fractures unstable; therefore, surgery is required in the majority of instances. The small size of the fractured component makes stabilization more difficult. Overall, anatomical scapular neck fractures are extremely uncommon and distinguished from other scapular fractures by their unique radiological and biomechanical characteristics. This case highlights the challenges encountered when managing scapular fractures in patients with morbid obesity. The delayed surgical intervention and the choice of surgical approach tailored to the patient's specific anatomical and physiological considerations proved to be effective in achieving a favorable outcome.

Congruent Concavity Restoration of the Reconstructed Glenoid After the Latarjet Procedure: Compensation for the Position of the Graft

BACKGROUND

Few clinical studies have addressed concavity restoration by natural remodeling after a Latarjet procedure. This study investigated the fibrous tissue and osseous remodeling of the reconstructed glenoid and concavity restoration after a Latarjet procedure using postoperative computed tomographic arthrography (CTA).

METHODS

This retrospective study included 31 patients who underwent immediate postoperative computed tomographic (CT) scanning followed by CTA at 6 months postoperatively. We investigated whether fibrous tissue was newly created over the graft, whether the created fibrous tissue restored the congruity of the articular surface and the osseous remodeling of the graft to the glenoid level (whether the osseous portion of the graft was remodeled flush to the glenoid level) and the concavity of the glenoid using the radius of a best-fit circle on the articular surface, and the relationship between the amount of created fibrous tissue and the position of the graft.

RESULTS

In all patients, the fibrous tissue on the graft yielded a smooth articular surface, as revealed by the CTA. The mean radius of the entire glenoid, including the transferred graft, was significantly smaller (p = 0.010) at 33.2 ± 8.5 mm than that of the glenoid posterior to the osseous step-off at 37.6 ± 9.4 mm, which is presumed to be the glenoid before the surgical procedure. Despite the congruity of the articular surfaces due to fibrous tissue seen in the CTA, 14 (45%) of 31 patients showed a subchondral osseous step-off on either the medial side or the lateral side in the immediate postoperative CT scans. However, through osseous remodeling, 8 of the 10 grafts with a lateral step-off and 2 of the 4 grafts with a medial step-off converted to a flush position. The position of the step-off was correlated with the thickness of the fibrous tissue, with a tendency for thicker tissue in cases of a step-off on the medial side (p = 0.014).

CONCLUSIONS

Fibrous tissue formation plus remodeling of the transferred graft resulted in the restoration of a congruent concavity after a Latarjet procedure by compensating for initially non-flush positioning of the graft. However, due to the small sample size in our study, clinical outcomes could not be correlated with radiographic findings, and our recommendation is to continue placing the graft as anatomically as possible.

LEVEL OF EVIDENCE

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

Scapula fractures: functional anatomy, clinical assessment and management

Fractures of the scapula are rare injuries, accounting for 3-5% of all shoulder girdle fractures. They are frequently the result of high energy trauma and often present with concurrent and life-threatening injuries to adjacent structures, leading to significant morbidity and mortality. Patients presenting with scapula fractures must receive a thorough and systematic clinical assessment as directed by national trauma guidelines. Appropriate imaging is essential in delineating fracture morphology and should at the very least include anteroposterior, anteroposterior oblique (Grashey) and axillary or scapula 'Y' view of the shoulder. Computed tomography imaging with three-dimensional reconstruction allows better delineation of the fracture morphology and helps with surgical planning. A lack of randomised controlled trials comparing the efficacy of conservative and operative management of scapula fractures has resulted in limited consensus for surgical indications. Nevertheless, most extra-articular fractures can be managed conservatively while intra-articular fractures of the glenoid frequently require surgical fixation.

Stability of novel cow-hitch suture button coracoid bone graft fixation in Latarjet procedures: a biomechanical study

BACKGROUND

The Latarjet procedure is widely used to address anterior shoulder instability, especially in case of glenoid bone loss. Recently, cortical suture button fixation for coracoid transfer has been used to mitigate complications seen with screw placement. The aim of this biomechanical study was to evaluate the stability of a novel and cost-effective cow-hitch suture button technique, designed to be performed through a standard open deltopectoral approach, and compare this to a well-established double suture button technique.

MATERIALS AND METHODS

We randomly assigned 12 fresh frozen cadaveric shoulders to undergo the Latarjet procedure with either 4 suture button (S&N EndoButton) fixations (SB group; n = 6, age 72 ± 9.8 years) or cow-hitch suture button technique using a 1.7-mm FiberTape looped sequentially in 2 suture buttons (Arthrex Pectoralis Button) placed from anterior on the posterior glenoid (CH-SB group; n = 6, age 73 ± 9.3 years). After fixation, all shoulders underwent biomechanical testing with direct loading on the graft via a material testing system. Cyclic loading was performed for 100 cycles (10-100 N) to determine axial displacement with time; each graft was then monotonically loaded to failure.

RESULTS

The maximum cyclic displacement was 4.3 ± 1.6 mm for the cow-hitch suture button technique and 5.0 ± 1.7 mm for the standard double suture button technique (P = .46). Ultimate load to failure and stiffness were, respectively, 190 ± 82 N and 221 ± 124 N/mm for the CH-SB technique and 172 ± 48 N and 173 ± 34 N/mm for the standard double SB technique (P = .66 and .43). The most common failure mode was suture cut-through at the anteroinferior aspect of the glenoid for both fixation groups.

CONCLUSIONS

The cow-hitch suture button technique resulted in a similar elongation, stiffness, and failure load compared to an established double suture button technique. Therefore, this cost-effective fixation may be an alternative, eligible for open approaches, to the established double suture button techniques.

Efficacy and safety of the Latarjet procedure for the treatment of athletes with glenoid bone defects ≥ 20%: a single-arm meta-analysis

BACKGROUND

The shoulder joint is the most commonly dislocated joint in the human body, and the recurrence rate exceeds 50% after nonsurgical treatment. Although surgical treatment reduces the recurrence rate, there is controversy regarding the optimal surgical approach. Previous studies suggest that the Latarjet procedure yields favourable outcomes for specific populations at risk of recurrence, such as competitive athletes with significant glenoid defects. However, most of the existing related research consists of nonrandomized controlled trials with small sample sizes, and there is a lack of strong evidence regarding the efficacy and safety of the Latarjet procedure.

METHODS

The PubMed, Embase, Cochrane Library, and Web of Science databases were systematically searched. Athletes with ≥ 20% glenoid defects were selected for inclusion. The following data were extracted: general patient information, instability rates, return to sports (RTS) rates, imaging features (graft positioning rate and graft healing rate), functional assessments [Rowe score, Athletic Shoulder Outcome Scoring System(ASOSS), visual analogue scale (VAS), forward flexion function, and external rotation function], and complications.

RESULTS

After excluding suspected duplicate cases, a total of 5 studies were included in this meta-analysis. The studies involved a total of 255 patients, including 237 males (93%) and 18 females (7%). The average age at the time of surgery was 25.4 ± 8.5 years. All the studies had a minimum follow-up period of 2 years, with an average follow-up time of 48.7 ± 18.9 months. The pooled rate of return to sport (RTS) was 94.3% (95% CI: 87.3%, 98.8%), and 86.1% (95% CI: 78.2%, 92.5%) of patients returned to their preoperative level of activity. The pooled redislocation rate was 1.1% (95% CI: 0%, 3.8%). Regarding the imaging results, the combined graft retention rate was 92.1% (95% CI: 88.1%, 95.5%), and the graft healing rate was 92.1% (95% CI: 88%, 95.4%). Postoperative functional evaluation revealed that the combined Rowe score, ASOSS score, and VAS score were 93.7 ± 6.5 points, 88.5 ± 4.4 points, and 1.1 ± 10 points, respectively. The forward flexion and external rotation angles were 170.9 ± 6.9 degrees and 65.6 ± 4.5 degrees, respectively. After excluding one study with unclear complications, the combined complication rate was 9.4% (95% CI: 1.0%, 23.6%).

CONCLUSION

For athletes with shoulder instability and a total of ≥ 20% glenoid bone defects, the Latarjet procedure can achieve excellent functional outcomes, with the majority of patients returning to preoperative levels of sports activity. This procedure also leads to a low recurrence rate. Therefore, the Latarjet procedure has been proven to be a safe and effective treatment.

Ipsilateral fractures of the acromion and coracoid processes of the scapula

A fracture of the acromion and coracoid processes of scapula is rarely seen in the outpatient clinic, due to the acromion's anatomical position and shape, as well as the strong ligaments and muscles that are attached to it. These fractures are caused by either direct or indirect high-energy trauma injuries to the shoulder joint, leading to severe pain and a grossly restricted range of motion. Several acromial classifications were reported, but this type of longitudinal plane fracture of the acromion process in our case is yet to be described in the current literature. We present a rare combination of the coracoid process and unstable acromion bony projection fractures that have not previously been noted for this type of fracture. The closest to this is Kuhn's type III classification. A 51-year-old male presented to our emergency department complaining of the right shoulder pain and difficulty raising his arm following a 2-wheeler accident. The patient was managed by open reduction and internal fixation with 3 cannulated cancellous screws fixation and progressed well with no postoperative complications. He was asymptomatic postoperatively and regained full range of motion after 4 months.

[Influencing factors on effectiveness of reverse total shoulder arthroplasty]

Objective

To summarize the influencing factors on the effectiveness of reverse total shoulder arthroplasty (RTSA), so as to provide reference for clinical treatment.

Methods

The related research literature of RTSA at home and abroad was extensively consulted, and the factors that may affect the effectiveness were summarized from the aspects of surgical technique, muscle condition, general condition of patients, psychological expectation, and lifestyle.

Results

For surgical techniques, different surgical approaches have their own advantages. The glenoid notch, poor bone ingrowth, increased bone resorption, and infection would lead to the loosening of glenoid prosthesis. In addition, the neck shaft angle and inclination angle of humeral prosthesis affect the occurrence of glenoid notch and the range of motion of joint internal/external rotation after operation, respectively. For muscle condition, the quality of teres minor and deltoid muscle has an important influence on joint stability after operation. Moderate increase of deltoid muscle tension can improve joint mobility after operation, and suture repair of subscapular tendon during operation can relieve joint pain and improve function, range of motion, and strength. For the general condition of patients, gender, age, and body mass index are all related to postoperative joint function and complications, and different occupations and postoperative exercise levels affect the recovery. The patients with severe degenerative diseases, poor preoperative function, and long disease duration have lower expectations and higher satisfaction with the effectiveness, and bad lifestyle has a negative impact on the effectiveness.

Conclusion

The effectiveness of RTSA is related to surgical technique, muscle condition, general condition of patients, psychological expectation, and lifestyle. In order to avoid the loosening of glenoid prosthesis, the operator should choose humeral prosthesis with small neck shaft angle and large glenoid ball and put them down and inclined inferiorly during operation, and choose appropriate approach to eliminate space with drainage to reduce the risk of infection. After operation, patients should avoid activities that generate high anterior and posterior shear forces. In addition, the humeral prosthesis with a inclination angle of 10°-20° can achieve the best balance between the range of internal rotation and external rotation after operation. Proper deltoid tension can maintain joint stability and good range of motion. Suture of subscapular tendon is recommended.

Outcomes and influencing factors of dental implants in fibula, iliac crest, and scapula free flaps: a retrospective case-control study

PURPOSE

Reconstruction with vascularized bone grafts after ablative surgery and subsequent dental rehabilitation with implants is often challenging; however, it helps improve the patient's quality of life. This retrospective case-control study aimed to determine the implant survival/success rates in different vascularized bone grafts and potential risk factors.

METHODS

Only patients who received implants in free vascularized bone grafts between 2012 and 2020 were included. The free flap donor sites were the fibula, iliac crest, and scapula. The prosthetic restoration had to be completed, and the observation period had to be over one year after implantation. Implant success was defined according to the Health Scale for Dental Implants criteria.

RESULTS

Sixty-two patients with 227 implants were included. The implant survival rate was 86.3% after an average of 48.7 months. The causes of implant loss were peri-implantitis (n = 24), insufficient osseointegration (n = 1), removal due to tumor recurrence (n = 1), and osteoradionecrosis (n = 5). Of all implants, 52.4% were classified as successful, 19.8% as compromised, and 27.8% as failed. Removal of osteosynthesis material prior to or concurrent with implant placement resulted in significantly better implant success than material not removed (p = 0.035). Localization of the graft in the mandibular region was associated with a significantly better implant survival (p = 0.034) and success (p = 0.002), also a higher Karnofsky Performance Status Scale score with better implant survival (p = 0.014).

CONCLUSION

Implants placed in vascularized grafts showed acceptable survival rates despite the potential risk factors often present in these patient groups. However, peri-implantitis remains a challenge.

3-dimensionally printed patient-specific glenoid drill guides vs. standard nonspecific instrumentation: a randomized controlled trial comparing the accuracy of glenoid component placement in anatomic total shoulder arthroplasty

BACKGROUND

Traditional, commercially sourced patient-specific instrumentation (PSI) systems for shoulder arthroplasty improve glenoid component placement but can involve considerable cost and outsourcing delays. The purpose of this randomized controlled trial was to compare the accuracy of glenoid component positioning in anatomic total shoulder arthroplasty (aTSA) using an in-house, point-of-care, 3-dimensionally (3D) printed patient-specific glenoid drill guide vs. standard nonspecific instrumentation.

METHODS

This single-center randomized controlled trial included 36 adult patients undergoing primary aTSA. Patients were blinded and randomized 1:1 to either the PSI or the standard aTSA guide groups. The primary endpoint was the accuracy of glenoid component placement (version and inclination), which was determined using a metal-suppression computed tomography scan taken between 6 weeks and 1 year postoperatively. Deviation from the preoperative 3D templating plan was calculated for each patient. Blinded postoperative computed tomography measurements were performed by a fellowship-trained shoulder surgeon and a musculoskeletal radiologist.

RESULTS

Nineteen patients were randomized to the patient-specific glenoid drill guide group, and 17 patients were allocated to the standard instrumentation control group. There were no significant differences between the 2 groups for native version (P = .527) or inclination (P = .415). The version correction was similar between the 2 groups (P = .551), and the PSI group was significantly more accurate when correcting version than the control group (P = .042). The PSI group required a significantly greater inclination correction than the control group (P = .002); however, the 2 groups still had similar accuracy when correcting inclination (P = .851). For the PSI group, there was no correlation between the accuracy of component placement and native version, native inclination, or the Walch classification of glenoid wear (P > .05). For the control group, accuracy when correcting version was inversely correlated with native version (P = .033), but accuracy was not correlated with native inclination or the Walch classification of glenoid wear (P > .05). The intraclass correlation coefficient was 0.703 and 0.848 when measuring version and inclination accuracy, respectively.

CONCLUSION

When compared with standard instrumentation, the use of in-house, 3D printed, patient-specific glenoid drill guides during aTSA led to more accurate glenoid component version correction and similarly accurate inclination correction. Additional research should examine the influence of proper component position and use of PSI on clinical outcomes.

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.

Femoral head allograft for glenoid bone loss in primary reverse shoulder arthroplasty: functional and radiologic outcomes

BACKGROUND

Several techniques have been adopted during primary reverse shoulder arthroplasty (RSA) to manage glenoid bone defect. Among bone grafts, humeral head autograft is currently the mainstream option. However, autologous humeral heads may be unavailable or inadequate, and allografts may be a viable alternative. The aim of the present study was to evaluate the functional and radiologic outcomes of femoral head allografts for glenoid bone defects in primary RSA.

METHODS

We conducted a retrospective study with prospective data collection enrolling 20 consecutive patients who underwent RSA with femoral head allografts for glenoid bone defects. Indications for surgery were eccentric cuff tear arthropathy in 10 cases (50%), concentric osteoarthritis in 9 cases (45%), and fracture sequelae in 1 case (5%). Each patient was evaluated preoperatively and at follow-up by radiologic and computed tomography (CT) and by assessing the range of motion (ROM) and the Constant-Murley score (CMS). A CT-based software, a patient-specific 3D model of the scapula, and patient-specific instrumentation were used to shape the graft and to assess the position of K-wire for the central peg. Postoperatively, CT scans were used to identify graft incorporation and resorption.

RESULTS

After a median follow-up of 26.5 months (24-38), ROM and CMS showed a statistically significant improvement (all P = .001). The median measures of the graft were as follows: 28 mm (28-29) for diameter, 22° (10°-31°) for angle, 4 mm (2-8 mm) for minimum thickness, and 15 mm (11-21 mm) for maximum thickness. Before the surgery, the median glenoid version was 21.8° (16.5°-33.5°) for the retroverted glenoids and -13.5° (-23° to -12°) for the anteverted glenoids. At the follow-up, the median postoperative baseplate retroversion was 5.7° (2.2°-1.5°) (P = .001), and this value was close to the 4° retroversion planned on the preoperative CT-based software. Postoperative major complications were noted in 4 patients: 2 dislocations, 1 baseplate failure following a high-energy trauma, and 1 septic baseplate failure. Partial graft resorption without glenoid component failure was observed in 3 cases that did not require revision surgery.

CONCLUSION

The femoral head allograft for glenoid bone loss in primary RSA restores shoulder function, with CMS values comparable to those of sex- and age-matched healthy individuals. A high rate of incorporation of the graft and satisfactory correction of the glenoid version can be expected after surgery. The management of glenoid bone defects remains a challenging procedure, and a 15% risk of major complication must be considered.

Baseplate inferior offset affects shoulder range of motion in reverse shoulder arthroplasty in Asian population

BACKGROUND

Impingement is a common complication of reverse shoulder arthroplasty. Placement of the baseplate with a wide impingement-free angle is ideal; however, there are few studies on Asian populations, which have smaller height and physique, and there is a lack of guidance on achieving optimal outcomes. The purpose of the present study was to explore the impingement-free range of motion reverse shoulder arthroplasty and analyze the suitable baseplate position or tilt for the Asian population using simulation software.

METHODS

We uploaded computed tomography scan data from 20 Asian patients to three-dimensional (3D) simulation software. The implantation of the reverse shoulder arthroplasty component was performed on the 3D humerus and scapula using software, and range of motion was assessed until impingement occurred.

RESULTS

The range of motion in flexion significantly improved when the baseplate was lowered up to 3 mm inferiorly. Range of motion in abduction and internal and external rotation significantly improved as the baseplate was lowered up to 4 mm. There was no significant difference in range of motion in any motion after changing the inferior tilt, except in internal and external rotation.

CONCLUSIONS

The range of motion in abduction, flexion, and internal and external rotations significantly improved with increased inferior offset. These results may prove valuable in determining the optimal baseplate position for RSA, particularly in Asian populations.

Determining optimal length of coracoid graft in the modified Bristow procedure for anterior shoulder instability: A three-dimensional finite element analysis

BACKGROUND

There is a lack of consensus concerning the coracoid graft length in the modified Bristow procedure.

OBJECTIVE

We attempted to determine the optimal graft length using the three-dimensional finite element method.

METHODS

In a shoulder model with a 25% anterior glenoid defect, a coracoid graft of varying lengths (5, 10, 15, and 20 mm) was fixed using a half-threaded screw. First, a compressive load of 500 N was applied to the screw head to determine the graft failure load during screw tightening. Next, a tensile load (200 N) was applied to the graft to determine the failure load due to biceps muscle traction.

RESULTS

In the screw compression, the failure loads in the 5-, 10-, 15-, and 20-mm models were 252, 370, 377, and 331 N, respectively. In the tensile load applied to the coracoid graft, the failure load exceeded 200 N for both the 5- and 10-mm models.

CONCLUSION

The 5-mm graft had a high risk of fracture during intraoperative screw tightening. As for the biceps muscle traction, the 5- and 10-mm-grafts had a lower failure risk than the 15- and 20-mm-grafts. Therefore, we believe that the optimal length of the coracoid graft is 10 mm in the modified Bristow procedure.

Advances in Oncologic Shoulder Girdle Resection and Reconstruction

The bony shoulder girdle consists of the clavicle, humerus, and scapula, which work synergistically to form a complex articulation that is essential for use of the upper extremity. The shoulder girdle is the most common location for primary and secondary bone tumors in the upper extremity, and following resection of these tumors, reconstruction of the upper extremity is challenging. Compared with those in the lower extremity, reconstructive techniques in the upper extremity have historically been unreliable and fraught with complications and poor functional outcomes. Newer reconstructive techniques using reverse total shoulder arthroplasty and functional muscle flaps have shown promise to improve outcomes while reducing complications for proximal humerus reconstructions. Despite these advancements, reconstruction following scapulectomy remains challenging and is still associated with more frequent complications and compromised function.

Editorial Commentary: Button Fixation for Glenoid Bone Grafting Results in Less Graft Resorption Compared to Screws

Iliac crest bone grafting is conducted in cases of anteroinferior shoulder instability with substantial bone loss of the glenoid rim to reconstruct the glenoid concavity and its stabilizing function. The technique is more than 100 years old, and it evolved to include graft fixation with metal screws. The disadvantages of metal screw fixation include risk of screw migration, loosening, and breakage, as well as irritation and injury to the surrounding osseous and soft tissue structures (e.g., humeral cartilage and subscapularis muscle). With the implementation of arthroscopic techniques, new graft fixation techniques were introduced, including absorbable or biologic screws, buttons, interconnected suture anchors, and bone cerclage techniques. Recent research shows button fixation is a successful alternative to screw fixation. In addition, buttons show less graft resorption and related pain.

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.

Intraoperative navigation system use increases accuracy of glenoid component inclination but not functional outcomes in reverse total shoulder arthroplasty: a prospective comparative study

BACKGROUND

While the use of computer-assisted navigation systems in prosthetic implantation is steadily increasing, its utility in reverse shoulder arthroplasty (RSA) remains unclear. The purpose of this study was to evaluate the clinical utility of an intraoperative navigation system in patients undergoing RSA.

MATERIALS AND METHODS

Patients undergoing navigated or standard RSA at a single institution between September 2020 and December 2021 were prospectively enrolled. Exclusion criteria included noncompliance with study procedures or humeral fracture. Outcome measures included postoperative version and inclination, range of motion (ROM), complications, and patient-reported outcome measurements (PROMs: American Shoulder and Elbow Surgeons score [ASES], Disabilities of the Arm, Shoulder, and Hand score [DASH], Simple Shoulder Test [SST], and Visual Analog Scale [VAS]) at final follow-up.

RESULTS

The final cohort contained 16 patients with navigation and 17 with standard RSA at a mean follow-up of 16 months (range 12-18 months). Average age was 72 years (range 66-80 years), 8 male (24%) and 25 female (76%). There were no differences in demographics between groups (p > 0.05). At baseline, the navigated group had a greater proportion of Walch B1 and B2 glenoids (p = 0.04). There were no differences between groups regarding baseplate type and native/planned/postoperative glenoid version and inclination. In both groups, planned and postoperative versions were not significantly different (p = 0.76). Patients who did not have navigation demonstrated significant differences between planned and postoperative inclination (p = 0.04), while those with navigation did not (p = 0.09). PROM scores did not differ between groups at final follow-up for SST (p = 0.64), DASH (p = 0.38), ASES (p = 0.77), or VAS (p = 0.1). No difference in final ROM was found between groups (p > 0.05). Over 50% of all screws in both groups were positioned outside the second cortex (p = 0.37), albeit with no complications.

CONCLUSIONS

There were no statistically significant differences in ROM, PROMs, and satisfaction between patients receiving computer-navigated and standard RSA at a short-term follow-up. Despite more severe preoperative glenoid erosion in the navigated group, all patients were able to achieve an appropriate neutral axis postoperatively. The cost effectiveness and appropriate use of computer-navigated RSA warrant specific investigation in future studies.

LEVEL OF EVIDENCE

II, prospective cohort study.

TRIAL REGISTRATION

9/1/2020 to 12/31/2021.

The process of bone union after arthroscopic bony Bankart repair in younger athletes with a subcritical glenoid defect: An advantage of remained large bone fragment

BACKGROUND

The purpose of the present study was to investigate the bone union process after arthroscopic bony Bankart repair (ABBR) in shoulders with a subcritical glenoid defect of 13.5% or larger.

METHODS

Bone union process after ABBR performed from 2011 to 2018 were retrospectively investigated in 47 athletes younger than 30 years with a subcritical glenoid defect, who underwent CT at least twice postoperatively. The change of bone union between first CT within 6 months and final CT later than 6 months was investigated, especially noticing bone fragment size (≥7.5% versus <7.5%).

RESULTS

The mean period at first CT and at final CT was 4.1 ± 0.6 months (3-6 months) and 16.8 ± 11.6 months (7-71 months), respectively. From the first to final CT, among 15 shoulders with a small bone fragment (<7.5%), complete union increased from 4 shoulders (26.7%) to 8 shoulders (53.3%), while among 32 shoulders with a large bone fragment (≥7.5%), complete union increased from 15 shoulders (46.9%) to 25 shoulders (78.1%). On the other hand, while non-union or disappeared bone fragment was recognized in 8 shoulders (53.3%) with a small fragment and in 2 shoulders (6.3%) with a large fragment at first CT, it was solely recognized in 4 shoulders (26.7%) with a small fragment and in no shoulders with a large fragment at final CT. While postoperative glenoid fracture at the site of bone union was recognized in 7 shoulders, complete union was finally obtained after conservative treatment in 5 shoulders. So, final complete union was obtained in 9 (60%) of 15 shoulders with a small fragment and in 29 (90.6%) of 32 shoulders with a large fragment (p = 0.021).

CONCLUSIONS

In shoulders with a subcritical glenoid defect, when a large bone fragment (≥7.5%) was repaired, complete union rate was higher and complete union could be obtained earlier.

Posterior Glenoid Bone Block Reconstruction: Indications, Techniques, and Outcomes

Posterior shoulder instability is of particular therapeutic interest, as it typically affects patients with high functional demands such as young athletes and active adults. Although posterior capsulolabral repair has high return-to-sport rates, it is associated with recurrent instability of up to 11%. Posterior glenoid bone loss and significant glenoid retroversion have been identified as risk factors for recurrent instability and failure after primary arthroscopic soft-tissue repair. Therefore, posterior glenoid bone block reconstruction may be indicated for glenoid bone loss 20% or greater (as measured by the perfect circle technique) or greater than 10% in the setting of pathologic glenoid, failed primary posterior labral repair, incompetent posterior capsular tissue, or significant risk factors for failure of soft-tissue repair. This procedure may be performed arthroscopically or with a posterior open approach using distal tibial allograft, iliac crest autograft, or scapular spine autograft. Although short-term to midterm outcomes have been promising, there remain concerns regarding long-term outcomes, with potentially high rates of late recurrence, revision, and secondary osteoarthritis.

Outcomes of conservative treatment of acromial and scapular spine stress fracture post reverse shoulder arthroplasty: a systematic review with meta-analysis

INTRODUCTION

Acromial and scapular spine stress fractures are common complications post reverse shoulder arthroplasty. A systematic review with meta-analysis was conducted to evaluate the clinical outcomes of conservatively treated acromial and scapular spine stress fractures post reverse shoulder arthroplasty in comparison to nonfracture control.

METHODS

Embase, MEDLINE, and Web of Science were searched on September 9, 2022, using various terms related to fracture, acromion, scapula, and reverse shoulder arthroplasty. Meta-analysis using a random effects model was performed on common outcome scores. Risk of bias was assessed using the Joanna Briggs Institute tools for case-controlled studies. Sensitivity analysis was performed for imputed standard deviations and studies with <20 participants.

RESULTS

Thirteen studies with a total of 339 fracture and 3142 control patients were included in the systematic review. Meta-analysis was performed on 12 studies assessing active forward flexion, abduction, external rotation, Constant-Murley score, American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form, pain score, Simple Shoulder Test, and Single Assessment Numeric Evaluation. Fracture patients experienced significantly poorer functional outcome compared with control patients when the fractures were managed conservatively. Levy III fractures tend to experience worse outcomes. Pain score did not demonstrate a statistically significant difference between the fracture and nonfracture cohort.

DISCUSSION

Currently, literature regarding surgical management is lacking, partially because of a dearth of high-quality literature but also hindered by a lack of standardized techniques. This review was limited by inclusion of studies of low evidence, small sample sizes, and inconsistency in outcome measurement and follow-up period. Overall, patients with acromial and scapular spine stress fractures treated conservatively are expected to have reduced shoulder function compared to nonfracture patients, with the spine of scapula fracture patients suffering the poorest outcomes. Future studies should aim to use the same sets of outcomes parameters to assess the patients at fixed time intervals and report outcomes stratified by Levy classification. This will enable interinstitutional collaboration and pooling of results.

Glenoid component placement in reverse shoulder arthroplasty assisted with augmented reality through a head-mounted display leads to low deviation between planned and postoperative parameters

BACKGROUND

Navigated augmented reality (AR) through a head-mounted display (HMD) may lead to accurate glenoid component placement in reverse shoulder arthroplasty (RSA). The purpose of this study is to evaluate the deviation between planned, intra- and postoperative inclination, retroversion, entry point, depth, and rotation of the glenoid component placement assisted by a navigated AR through HMD during RSA.

METHODS

Both shoulders of 6 fresh frozen human cadavers, free from fractures or other bony pathologies, were used. Preoperative computed tomography (CT) scans were used for the 3-dimensional (3D) planning. The glenoid component placement was assisted using a navigated AR system through an HMD in all specimens. Intraoperative inclination, retroversion, depth, and rotation were measured by the system. A postoperative CT scan was performed. The pre- and postoperative 3D CT scan reconstructions were superimposed to calculate the deviation between planned and postoperative inclination, retroversion, entry point, depth, and rotation of the glenoid component placement. Additionally, a comparison between intra- and postoperative values was calculated. Outliers were defined as >10° inclination, >10° retroversion, >3 mm entry point.

RESULTS

The registration algorithm of the scapulae prior to the procedure was correctly completed for all cases. The deviations between planned and postoperative values were 1.0° ± 0.7° for inclination, 1.8° ± 1.3° for retroversion, 1.1 ± 0.4 mm for entry point, 0.7 ± 0.6 mm for depth, and 1.7° ± 1.6° for rotation. The deviation between intra- and postoperative values were 0.9° ± 0.8° for inclination, 1.2° ± 1.1° for retroversion, 0.6 ± 0.5 mm for depth, and 0.3° ± 0.2° for rotation. There were no outliers between planned and postoperative parameters.

CONCLUSION

In this study, the use of a navigated AR system through an HMD for RSA led to low deviation between planned and postoperative values and between intra- and postoperative parameters.

Arthroscopic Bankart repair with peeling osteotomy of the anterior glenoid rim preserves glenoid morphology

BACKGROUND

A decrease in the glenoid size after arthroscopic Bankart repair (ABR) was common in shoulders without osseous fragments compared with those with osseous fragments. For cases of chronic recurrent traumatic anterior glenohumeral instability without osseous fragments, we have performed ABR with peeling osteotomy of the anterior glenoid rim (ABRPO) to make an intentional osseous Bankart lesion. The aim of this study was to compare the glenoid morphology after ABRPO with it after simple ABR.

METHODS

The medical records of patients who underwent arthroscopic stabilization for chronic recurrent traumatic anterior glenohumeral instability were retrospectively reviewed. Patients with an osseous fragment, with revision surgery and without complete data were excluded. Patients were assigned to 1 of 2 groups: Group A, ABR without peeling osteotomy procedure or Group B, with ABRPO procedure. Computed tomography was performed preoperatively and 1 year after surgery. The size of the glenoid bone loss was investigated by the assumed circle method. The following formula was used to calculate the decreased size of the glenoid: (Δ) = (postoperative size of the glenoid bone loss) - (preoperative size of the glenoid bone loss). The size of the glenoid 1 year after surgery was assessed to determine if it had decreased (Δ > 0%) or not decreased (Δ ≤ 0%) relative to the preoperative size.

RESULTS

This study evaluated 39 shoulders divided into 2 groups: 27 shoulders in Group A and 12 shoulders in Group B. In Group A, postoperative glenoid bone loss was significantly greater than preoperative glenoid bone loss (7.8 ± 6.2 vs. 5.5 ± 5.3, respectively, P = .02). In Group B, postoperative glenoid bone loss was significantly lower than preoperative glenoid bone loss (5.6 ± 5.4 vs. 8.7 ± 4.0, respectively, P = .02). The P value for the interaction of group (A or B) × time (preoperative or postoperative) was 0.001. The decreased size of the glenoid was significantly larger in Group A than in Group B (2.1 ± 4.2 vs. -3.1 ± 4.5, respectively, P = .001). The rate of shoulders in which the size of the glenoid decreased 1 year after surgery relative to the preoperative size was significantly higher in Group A than in Group B (63% [17/27] vs. 25% [3/2], respectively, P = .04).

CONCLUSIONS

The study showed that ABRPO preserved the glenoid size better than simple ABR without a peeling osteotomy procedure.

Modification of the pedicled osteomuscular dorsal scapula flap to include a skin paddle

This article describes a reliable surgical alternative for the repair of wide oromandibular defects that require bone and soft tissues, which was applied in two patient cases. While microvascular free flap transfer, especially the fibula flap, is the gold standard for mandibular reconstruction, this reconstruction is challenging in patients with a vessel-depleted neck and/or severe arteriosclerosis. The pedicled osteomuscular dorsal scapular (OMDS) flap is a surgical alternative to free flap transfer in this clinical setting. The technique described involves harvesting of the OMDS flap to include a skin paddle, which is often required to close wide oral mucosal defects.

Risk factors of acromial and scapular spine stress fractures differ by indication: a study by the ASES Complications of Reverse Shoulder Arthroplasty Multicenter Research Group

BACKGROUND

Both patient and implant related variables have been implicated in the incidence of acromial (ASF) and scapular spine fractures (SSF) following reverse shoulder arthroplasty (RSA); however, previous studies have not characterized nor differentiated risk profiles for varying indications including primary glenohumeral arthritis with intact rotator cuff (GHOA), rotator cuff arthropathy (CTA), and massive irreparable rotator cuff tear (MCT). The purpose of this study was to determine patient factors predictive of cumulative ASF/SSF risk for varying preoperative diagnosis and rotator cuff status.

METHODS

Patients consecutively receiving RSA between January 2013 and June 2019 from 15 institutions comprising 24 members of the American Shoulder and Elbow Surgeons (ASES) with primary, preoperative diagnoses of GHOA, CTA and MCT were included for study. Inclusion criteria, definitions, and inclusion of patient factors in a multivariate model to predict cumulative risk of ASF/SSF were determined through an iterative Delphi process. The CTA and MCT groups were combined for analysis. Consensus was defined as greater than 75% agreement amongst contributors. Only ASF/SSF confirmed by clinical and radiographic correlation were included for analysis.

RESULTS

Our study cohort included 4764 patients with preoperative diagnoses of GHOA, CTA, or MCT with minimum follow-up of 3 months (range: 3-84). The incidence of cumulative stress fracture was 4.1% (n = 196). The incidence of stress fracture in the GHOA cohort was 2.1% (n = 34/1637) compared to 5.2% (n = 162/3127) (P < .001) in the CTA/MCT cohort. Presence of inflammatory arthritis (odds ratio [OR] 2.90, 95% confidence interval [CI] 1.08-7.78; P = .035) was the sole predictive factor of stress fractures in GHOA, compared with inflammatory arthritis (OR 1.86, 95% CI 1.19-2.89; P = .016), female sex (OR 1.81, 95% CI 1.20-2.72; P = .007), and osteoporosis (OR 1.56, 95% CI 1.02-2.37; P = .003) in the CTA/MCT cohort.

CONCLUSION

Preoperative diagnosis of GHOA has a different risk profile for developing stress fractures after RSA than patients with CTA/MCT. Though rotator cuff integrity is likely protective against ASF/SSF, approximately 1/46 patients receiving RSA with primary GHOA will have this complication, primarily influenced by a history of inflammatory arthritis. Understanding risk profiles of patients undergoing RSA by varying diagnosis is important in counseling, expectation management, and treatment by surgeons.

Recurrent Instability after the Latarjet Procedure

The Latarjet procedure is a favored approach for managing chronic and recurrent dislocation, especially in the presence of bone loss. Although generally yielding excellent results, the procedure carries a 15 to 30% complication rate. Although recurrent instability is a major concern, various complications such as infection, nerve injuries, and hardware impingement can also necessitate revision after a Latarjet procedure. Strategies for addressing this issue include glenoid bone grafting, using autogenous bone grafts from the iliac crest or distal clavicle, and allografts, with fresh lateral distal tibial allografts offering advantages because of their osteochondral nature. In addition, soft-tissue procedures offer another solution for recurrent instability, suitable for patients lacking substantial bone loss or those experiencing multidirectional instability. This review aims to provide a comprehensive overview of the causes and management strategies for recurrent instability following a failed Latarjet procedure.

Review of Burkhart and DeBeer's (2000) article on traumatic glenohumeral bone defects and their relationship to failure of arthroscopic Bankart repair: Where have we taken the concept of glenoid bone loss in 2023?

This classic discusses the original publication by Burkhart and DeBeer "Traumatic Glenohumeral Bone Defects and Their Relationship to Failure of Arthroscopic Bankart Repair" published in 2000 in Arthroscopy. At that time, the authors sought to understand the reasons behind the failure of arthroscopic soft tissue repair. Based on their findings, the authors introduced the concept of the inverted pear glenoid and engaging Hill-Sachs lesion which is now part of the orthopedic lexicon. The importance of bony pathologic changes in anterior glenohumeral instability has become so apparent, that it now forms the basis of clinical understanding and underpins treatment algorithms. Since this publication over 20 years ago, the idea of glenohumeral bone loss has been extensively explored and refined. There is no doubt of the importance of structural bone loss yet there is still uncertainty as to the best management of those with subcritical bone loss. The purpose of revisiting this classic article is to look at where we are in understanding recurrent instability and bony deficiency while appreciating how far we have come. This review begins with a detailed summary of the classic article along with a historic perspective. Next, we look at the current evidence as it pertains to the classic article and how modern technology and innovation has advanced our ability to assess and quantify glenohumeral bone loss. We finish with expert commentary on the topic from two current surgeons with a research interest in shoulder instability to offer an insight into how modern surgeons view and address this issue. One of the original authors also reflects on the topic. The findings of this classic study changed the way we think about shoulder instability and opened the doors to an exciting body of research that is still growing today. Future research offers an opportunity for high quality evidence to guide management in the group of patients with subcritical bone loss and we eagerly await the results.

Minimally invasive plate osteosynthesis (MIPO) for scapular fractures

OBJECTIVE

Presentation of a minimally invasive surgical approach for the treatment of scapular fractures and the clinical outcome using this technique.

INDICATIONS

Displaced extra-articular fractures of the scapula body and glenoid neck (AO 14B and 14F) and simple intra-articular fractures of the glenoid.

CONTRAINDICATIONS

Complex intra-articular fractures and isolated fractures of the coracoid base.

SURGICAL TECHNIQUE

Make a straight or slightly curved incision along the lateral margin of the scapula leaving the deltoid fascia intact. Identify the interval between the teres minor muscle and infraspinatus to visualize the lateral column, whilst retracting the deltoid to visualize the glenoid neck. Reduce and align the fracture using direct and indirect reduction tools. A second window on the medial border of the scapula can be made to aid reduction and/or to augment stability. Small (2.0-2.7 mm) plates in a 90° configuration on the lateral border and, if required, on the medial border are used. Intra-operative imaging confirms adequate reduction and extra-articular screw placement.

POSTOPERATIVE MANAGEMENT

Direct postoperative free functional nonweight-bearing rehabilitation limited to 90° abduction for the first 6 weeks. Sling for comfort. Free range of motion and permissive weight-bearing after 6 weeks.

RESULTS

We collected data from 35 patients treated with minimally invasive plate osteosynthesis (MIPO) between 2011 and 2021. Average age was 53 ± 15.1 years (range 21-71 years); 17 had a type B and 18 a type F fracture according the AO classification. All patients suffered concomitant injuries of which thoracic (n = 33) and upper extremity (n = 25) injuries were most common. Double plating of the lateral border (n = 30) was most commonly performed as described in the surgical technique section. One patient underwent an additional osteosynthesis 3 months after initial surgery due to pain and lack of radiological signs of healing of a fracture extension into the spine of the scapula. In the same patient, the plate on the spine of scapula was later removed due to plate irritation. In 2 patients postoperative images showed a screw protruding into the glenohumeral joint requiring revision surgery. After standardisation of intra-operative imaging following these two cases, intra-articular screw placement did not occur anymore. No patient suffered from iatrogenic nerve injury and none developed a wound infection.

Oncological and functional outcomes after resection of malignant tumours of the scapula

Aims

The scapula is a rare site for a primary bone tumour. Only a small number of series have studied patient outcomes after treatment. Previous studies have shown a high rate of recurrence, with functional outcomes determined by the preservation of the glenohumeral joint and deltoid. The purpose of the current study was to report the outcome of patients who had undergone tumour resection that included the scapula.

Methods

We reviewed 61 patients (37 male, 24 female; mean age 42 years (SD 19)) who had undergone resection of the scapula. The most common resection was type 2 (n = 34) according to the Tikhoff-Linberg classification, or type S1A (n = 35) on the Enneking classification.

Results

The ten-year disease-specific survival was 76%. High tumour grade (hazard ratio (HR) 4.27; p = 0.016) and a total resection of the scapula (HR 3.84; p = 0.015) were associated with worse survival. The ten-year metastasis-free and local recurrence-free survivals were 82% and 86%, respectively. Total scapular resection (HR 6.29; p = 0.004) was associated with metastatic disease and positive margins were associated with local recurrence (HR 12.86; p = 0.001). At final follow-up, the mean shoulder forward elevation and external rotation were 79° (SD 62°) and 27° (SD 25°), respectively. The most recent functional outcomes evaluated included the mean Musculoskeletal Tumor Society Score (76% (SD 17%)), the American Shoulder and Elbow Score (73% (SD 20%)), and the Simple Shoulder Test (7 (SD 3)). Preservation of the glenoid (p = 0.001) and scapular spine (p < 0.001) improved clinical outcomes; interestingly, preservation of the scapular spine without the glenoid improved outcomes (p < 0.001) compared to preservation of the glenoid alone (p = 0.05).

Conclusion

Resection of the scapula is a major undertaking with an oncological outcome related to tumour grade, and a functional outcome associated with the status of the scapular spine and glenoid. Positive resection margins are associated with local recurrence.

Which Components of the Simple Shoulder Test Show Improvement After Scapulothoracic Fusion for Recalcitrant Scapular Winging? Clinical Results at a Minimum of 5 Years of Follow-up

BACKGROUND

Scapular winging is an uncommon but important cause of shoulder pain and disability. Surgical management can include soft tissue procedures such as split pectoralis major transfer, the Eden-Lange procedure, or a triple tendon transfer. When these procedures do not alleviate symptomatic winging or are inappropriate, scapulothoracic fusion is an alternative, but data on its longer-term effectiveness are sparse.

QUESTIONS/PURPOSES

(1) What changes in outcome scores were observed (VAS, Single Assessment Numeric Evaluation [SANE], and Simple Shoulder Test [SST] scores), and what proportion of the patients improved by an amount larger than the minimum clinically important difference (MCID) for the outcome tool in question? (2) Which components of the SST are patients able to perform at a minimum of 5 years? (3) What complications occurred after surgery?

METHODS

We performed a retrospective study in a single, large, urban referral medical center of patients who underwent scapulothoracic fusion. Between January 2011 and November 2016, 15 patients underwent scapulothoracic fusion to treat symptomatic scapular winging. Only patients with nondystrophic etiology were included in the analysis (n = 13). Of the 13 remaining patients, one patient was lost to follow-up and another patient died during data collection, leaving 11 patients for the final analysis. Six patients had brachial plexus injuries affecting multiple nerve roots and periscapular muscles, and five had persistent symptoms despite prior tendon transfer. The median age of the patients was 43 years (range 20 to 67 years), and there were six male and five female patients. All patients had a minimum of 5 years of follow-up. There was a median follow-up of 79 months (range 61 to 128 months). The VAS pain score (range 0 to 10, higher scores represent more pain; MCID = 2), SST score (range 0 to 12, higher scores represent less pain and better shoulder function; MCID = 2.3), and SANE score (range 0 to 100, higher scores represent better shoulder function; MCID = 28) were recorded before surgery and at the most recent follow-up. We compared scores from before surgery with those taken at the most recent follow-up and ascertained the proportion of patients whose improvement exceeded the MCID. The number of patients achieving fusion (as confirmed by a CT image), complications, and reoperations was recorded via a record review as well as direct patient query by telephone.

RESULTS

The median VAS pain score improved from 7 (range 3 to 10) preoperatively to 3 (range 2 to 5) at the latest follow-up (p < 0.001). The median SANE score improved from 30 (range 0 to 60) preoperatively to 65 (range 40 to 85) at the latest follow-up (p < 0.001). The median SST score improved from 0 (range 0 to 9) to 8 (range 5 to 10) at the latest follow-up (p < 0.001). Ten of 11 patients had improvements exceeding the MCID for VAS, six of 11 had improvements for SANE scores, and nine of 11 had improvements for SST. Preoperative to postoperative improvements in these components of the SST were seen (responses of "yes"): comfort at rest (three of 11 improved to 11 of 11; p < 0.001), sleep comfortably (three of 11 improved to 11 of 11; p < 0.001), place coin on shelf (two of 11 improved to 10 of 11; p < 0.001), lift 1 pound above shoulder (two of 11 improved to eight of 11; p = 0.03), and carry 20 pounds with the arm at side (one of 11 improved to nine of 11; p < 0.001). All 11 patients had successful fusion noted on CT images. There were three complications (progression of glenohumeral arthritis, broken wires, and perioperative chest tube placement) and one reoperation for progression of glenohumeral arthritis with subsequent total shoulder arthroplasty.

CONCLUSION

Patients with recalcitrant symptomatic scapular winging often undergo an exhaustive course of clinical examinations, diagnostic tests, physical therapy, and multiple surgical procedures. Those with brachial plexus palsy with involvement of multiple nerves may continue to have symptoms despite nonoperative management and subsequent soft tissue tendon transfers. Scapulothoracic fusion could be considered for patients with persistent pain and decreased function because of recalcitrant scapular winging who are either not candidates for the procedure or have persistent symptoms despite prior soft tissue procedures.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

How many anchors to use in arthroscopic Bankart repairs? A biomechanical study of postage-stamp glenoid fractures

BACKGROUND

Deciding how many anchors to use in a Bankart repair is challenging because of the desire to enhance stability while avoiding a postage-stamp fracture of the glenoid rim.

METHODS

This controlled laboratory study investigated load to fracture of the anterior glenoid rim after drilling holes of varying number and diameter and inserting anchors of 2 different types and sizes, with and without perforation of the medial cortex of the glenoid, creating postage-stamp fractures using a metallic humeral head that was compressed against the anterior glenoid rim. A destructive model with a servohydraulic load frame was used to test 46 synthetic scapulae with compressive strength and elastic modulus similar to that of a human glenoid. Load to fracture of the intact glenoid was compared with groups with a varying number of anchor holes of different diameters, with anchors of different sizes and types, and with anchors perforating or not perforating the glenoid medial cortex. The percentage of force to fracture an intact specimen was used to identify relative risk of fracture: low risk >75%, moderate risk 75%-50%, and high risk <50% of intact load.

RESULTS

The load to fracture of intact glenoids was 1276 ± 42 N. Loads decreased linearly as the number of holes drilled on the glenoid rim increased. Compared with the 1.6-mm group, the 3.0-mm group had significantly lower glenoid rim strength in specimens with 4, 5, and 7 holes (P = .013, .032, and .045, respectively). All-suture anchors in 1.6-mm holes did not alter the glenoid rim strength, and up to 5 anchors were associated with low risk of fracture. Load to fracture was significantly higher with 3.0-mm rigid core bioabsorbable anchors with 4 anchors (1081 ± 6 N) compared with the 4-hole condition (838 ± 107 N; P = .033). Perforating the glenoid medial cortex with five 1.6-mm anchors significantly weakened the glenoid rim to 58% of intact (P = .012). Perforating the medial cortex weakened the glenoid rim to 52% and 42% (P < .001 for both) of intact in the 3.0-mm 4-anchor and 5-anchor constructions, constituting moderate and high risk of fracture, respectively.

CONCLUSION

Up to five 1.6-mm all-suture anchors and four 3.0-mm bioabsorbable rigid-core anchors were associated with low risk of fracture of the glenoid rim. Smaller diameter all-suture anchors best preserved structural integrity of the glenoid rim, whereas tunnel enlargement and perforation of the glenoid medial cortex were associated with moderate or high risk of a postage-stamp fracture.

Risk avoidance of screw-induced suprascapular nerve injury in arthroscopic Latarjet procedure and reliable anatomical landmark analysis of Latarjet surgery

OBJECTIVE

Shoulder dislocation represents a prevalent category within joint dislocation, accounting for about 40% of all joint dislocations, and anterior dislocation stands out as the prevailing type. It has been reported that in 1.6% of patients, the Latarjet procedure performed under arthroscopy involves transferring the coracoid process to the anterior-inferior aspect of the glenoid and fixing it with two bicortical screws. The tip of the screws may impinge the suprascapular nerve located behind the scapula, resulting in shoulder pain and weakness. This study was performed to analyze the risk of suprascapular nerve (SSN) injury caused by bicortical screws during arthroscopic Latarjet surgery and to identify reliable anatomical landmarks for Latarjet surgery.

MATERIALS AND METHODS

Dissection was conducted on 23 fresh adult intact shoulder joint specimens, and the experimental protocol complied with the hospital's ethical requirements for research. Using the glenoid clock face as a reference, the distances between the suprascapular nerve and the anterior edge of the glenoid were measured at the 12:00, 11:00, 10:00, and 9:00 positions, as well as at the level of the suprascapular notch and the level of the spinoglenoid notch. The distances between the suprascapular nerve and the narrowest point of the glenoid rim and the clock scale were recorded. The scapula was divided into three zones, and the number of nerve branches in each zone was recorded. The collected data were subjected to statistical analysis. The suprascapular nerve trunk and branches were marked using radiopaque lines, and measurements were taken at three positions in computed tomography horizontal scans: the suprascapular foramen, the spinoglenoid notch, and the point of entry of the outermost nerve branch into the muscle.

RESULTS

The suprascapular nerve originates from the brachial plexus, passes downward and backward through the suprascapular foramen, closely adheres to the bone surface, and runs outward and downward deep to the supraspinatus muscle. The distances between the suprascapular nerve and the glenoid rim at the 12:00, 11:00, 10:00, and 9:00 positions were 335.18±2.31 mm, 28.23±3.47 mm, 22.32±2.78 mm, and 22.12±2.07 mm, respectively. There was a mean of 1.12 nerve branches in zone 1, 2.86 in zone 2, and 3.64 in zone 3. In the neutral position of the shoulder joint, the horizontal distance between point A and the axillary nerve was 27.37 (19.80, 34.55) mm, and the vertical distance was 16.67 (12.85, 20.35) mm.

CONCLUSIONS

The use of bicortical screws, especially upper screws, for Latarjet fixation at the level of the spinoglenoid notch, is associated with the risk of suprascapular nerve injury. The narrowest distance between the glenoid rim and the suprascapular nerve was found between 9:00 and 9:30 at the glenoid clock surface. Therefore, caution should be exercised when performing any procedure related to this area. Overall, the Latarjet procedure is a reliable and effective surgical technique, providing benefits such as favorable positioning of the coracoid graft and low bone absorption rate, while also avoiding the potential for suprascapular nerve injury.

Glenoid Bone Loss in Recurrent Shoulder Instability After Arthroscopic Bankart Repair: A Systematic Review

BACKGROUND

Glenoid bone loss has been reported to occur in as many as 86% of patients with recurrent shoulder stability. This systematic review evaluated the amount of glenoid bone loss associated with recurrent shoulder dislocation or subluxation and with worse patient-reported outcomes after arthroscopic Bankart repair. We hypothesized that the percentage of glenoid bone loss associated with recurrent instability after arthroscopic Bankart repair is lower than the previously proposed critical value of 25%.

METHODS

The systematic review included 528 patients with glenoid bone loss from 3 clinical studies. The percentage of bone loss was the value quantified and reported in each study. Failure was defined as recurrent dislocation or subluxation. The percentage of glenoid bone loss associated with recurrent shoulder dislocation or subluxation after arthroscopic Bankart labral repair was analyzed with receiver operating characteristic (ROC) curve analysis.

RESULTS

Recurrent dislocation or subluxation occurred in 23.7% (125) of 528 patients in the pooled study cohort. There was a significant difference in age between those in whom the arthroscopic Bankart repair failed and those in whom it did not (22.9 versus 24.3 years; p = 0.009). The ROC curve analysis demonstrated that ≥16.0% glenoid bone loss was predictive of recurrent shoulder dislocation or subluxation (Youden index = 0.59, sensitivity = 80%, specificity = 80%). In patients who did not sustain a recurrent dislocation or subluxation, the ROC curve analysis demonstrated that 20.0% glenoid bone loss was predictive of a Single Assessment Numeric Evaluation (SANE) score of <85% (Youden index = 0.93, sensitivity = 93%, specificity = 100%).

CONCLUSIONS

The critical amount of glenoid bone loss associated with an increased risk of persistent instability was found to be less than previously reported. Glenoid bone loss of ≥16.0% was found to place patients at higher risk for recurrent shoulder dislocation or subluxation after treatment with arthroscopic Bankart repair alone.

LEVEL OF EVIDENCE

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

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

Aims

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

Methods

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

Results

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

Conclusion

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

[Clinical analysis of posterior axillary approach internal fixation for IdebergⅠa andⅡglenoid fractures]

OBJECTIVE

To investigate the efficacy of posterior axillary approach internal fixation for Ideberg Ⅰa andⅡ glenoid fractures.

METHODS

From December 2018 to September 2021, 9 patients with lower part of glenoid fractures were treated by posterior axillary approach, including 3 males and 6 females, aged from 50 to 78 years old. All the fractures were closed fractures. According to Ideberg type of scapular glenoid fracture was type Ⅰa in 6 cases and type Ⅱ in 3 cases. AP and lateral X-ray films of scapula were taken at 6, 12 weeks and 6 and 12 months postoperatively. Constant-Murley and disabilities of the arm shoulder and hand (DASH), and other complications were recorded at the latest follow-up.

RESULTS

Nine patients were followed up, ranged from 6 to 15 months. And bone healing was achieved in all 9 patients at the final follow-up, the healing time 3 to 6 months, Constant-Murley score at the final follow-up ranged from 55 to 96, and DASH score ranged from 3.33 to 33.33. Both of them were better than preoperative.

CONCLUSION

The posterior axillary approach internal fixation for Ideberg Ⅰa and Ideberg Ⅱ Glenoid fractures scapular fracture is satisfactory and worthy of clinical application.

Assessment of micromotion at the bone-bone interface after coracoid and scapular-spine bone-block augmentation for the reconstruction of critical anterior glenoid bone loss-a biomechanical cadaver study

BACKGROUND

Glenoid bone loss is among the most important risk factors for recurrent anterior shoulder instability, and a bony reconstruction is recommended in cases of critical bone loss (> 15%). The commonly used surgical techniques, including coracoid transfer, are associated with considerable complications. The aim of this study was to assess the motion at the glenoid-bone-block interface after coracoid and spina-scapula bone-block reconstruction of the anterior glenoid.

METHODS

Twelve cadaveric shoulders were tested. A 20% bone defect of the anterior glenoid was created, and the specimens were randomly assigned for glenoid augmentation using a coracoid bone block (n = 6) or a scapular spine bone block (n = 6). The glenoid-bone interface was cyclically loaded for 5000 cycles with a force of 170 N. The micromotion was tracked using an optical measurement system (GOM ARMIS) and was evaluated with the GOM Correlate Pro software.

RESULTS

The most dominant motion component was medial irreversible displacement for the spina-scapula (1.87 mm; SD: 1.11 mm) and coracoid bone blocks (0.91 mm; SD: 0.29 mm) (n.s.). The most medial irreversible displacement took place during the first nine cycles. The inferior reversible displacement was significantly greater for spina-scapula bone blocks (0.28 mm, SD: 0.16 mm) compared to coracoid bone blocks (0.06 mm, SD: 0.10 mm) (p = 0.02).

CONCLUSIONS

The medial irreversible displacement is the dominant motion component in a bone-block reconstruction after a critical bone loss of the anterior glenoid. The spina-scapula and coracoid bone blocks are comparable in terms of primary stability and extent of motion. Thus, spina-scapula bone blocks may serve as alternatives in bony glenoid reconstruction from a biomechanical point of view.