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.

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.

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.

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.

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 (ß 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 ß 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 ß 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.

[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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.