Risk Factors of Graft Resorption after Arthroscopic Autologous Scapular Spine Bone Graft for Recurrent Shoulder Instability

Graft Resorption After Posterior Distal Tibial Allograft Augmentation for Posterior Shoulder Instability: A Case Report

CASE

A 19-year-old man underwent arthroscopic posterior glenoid reconstruction with a distal tibia allograft (DTA) after failing 2 posterior, soft-tissue instability surgeries. Although he experienced near-complete resolution of symptoms and return to sport, graft resorption was noted 7 months postoperatively. The patient underwent revision surgery for screw removal.

CONCLUSION

Graft resorption has not previously been reported in the setting of arthroscopic DTA use for posterior instability. It is believed that stress shielding contributed to resorption. In such situations, screw removal may be warranted. Consideration of alternative fixation techniques and additional investigation into the causes, clinical significance, and optimal management of posterior DTA resorption are warranted.

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.

Novel Claw-shaped Bone Plate in Complex Unstable Scapular Neck and Body Fractures: Comparison with Reconstruction Locking Plate

OBJECTIVE

For complex and unstable scapular fractures requiring simultaneous fixation of the glenoid neck, the lateral margin of the body, and/or the scapular diaphysis, reconstruction locking plate is difficult to achieve satisfactory fixation. In order to optimize the fixation effect, the newly designed claw-shaped bone plate was designed for fixing such fractures. We also evaluate the clinical effects and follow-up at an average of 1 year after treatment in scapular internal fixation by using reconstruction locking plate and claw-shaped bone plate in complex unstable scapular body and glenoid neck fracture.

METHODS

A retrospective study was conducted from 2018 to 2021, thirty-three patients (27 males and six females) who were defined unstable scapular fractures by Ada-Miller. Fifteen patients (52.86 ± 8.26 years) received claw-shaped bone plate and 18 cases (51.61 ± 11.31 years) received reconstruction locking plate with the intermuscular approach. The clinical effect was evaluated based on the operation time, intraoperative blood loss, surgical complications, clinical healing time and Constant-Murley score (CMS). The data analysis by Student t, Mann-Whitney U test and Pearson's chi squared test.

RESULTS

Compared with reconstruction locking plate, the claw-shaped bone plate showed shorter operation time (102.73 ± 18.43 min vs. 156 ± 37.53, P < 0.0001), higher CMS (94.00 ± 4.07 vs. 89.88 ± 5.42, P = 0.02) and no differences between the two groups regarding intraoperative blood loss (208.00 ± 96.45 mL vs. 269.44 ± 120.21, P = 0.12) and clinical healing times (9.96 ± 1.52 vs. 10.05 ± 1.67, P = 0.87). Follow-up were conducted at first, third, 6 and 12 months after surgery. The operation was successful in all patients with no intraoperative complications.

CONCLUSIONS

For the treatment of complex and unstable scapular neck body fractures, the application of claw-shaped bone plate demonstrated short operation time, better stability of the fracture block, and higher CMS. In the intraoperative and postoperative follow-up showed better clinical results and rehabilitation effects.

Effect of body mass index on progressive bone mineral density in patients with cleft after secondary alveolar bone grafting

BACKGROUND

Although childhood obesity matters, the association between body mass index (BMI) and bone mineral density (BMD) progression in grafted tissue after secondary alveolar bone grafting (ABG) for children with cleft alveolus is scarcely studied. Accordingly, this study explored the influence of BMI on BMD progression after ABG.

METHODS

In total, 39 patients with cleft alveolus receiving ABG at the mixed dentition stage were enrolled. Patients were classified as underweight, normal weight, or overweight or obese according to age- and sex-adjusted BMI. BMD was measured in Hounsfield units (HU) from cone-beam computed tomography scans obtained 6 months (T1) and 2 years (T2) postoperatively. Adjusted BMD (HU_{grafted tissue}/HU_pogonion, BMD_a) was used for further analysis.

RESULTS

For underweight, normal-weight, and overweight or obese patients, BMD_aT1 values were 72.87%, 91.85%, and 92.89%, respectively (p = 0.727); BMD_aT2 values were 111.49%, 112.57%, and 113.10% (p = 0.828); and density enhancement rates were 29.24%, 24.61%, and 22.14% (p = 0.936). No significant correlation was observed between BMI and BMD_aT1, BMD_aT2, or density enhancement rates (p = 0.223, 0.156, and 0.972, respectively). For patients with BMI < 17 and ≥ 17 kg/m², BMD_aT1 values were 89.80% and 92.89%, respectively (p = 0.496); BMD_aT2 values were 111.49% and 113.10% (p = 0.216); and density enhancement rates were 23.06% and 26.39% (p = 0.573).

CONCLUSION

Patients with different BMI values had similar outcomes (BMD_aT1, BMD_aT2, or density enhancement rate) after our ABG procedure in the 2-year postoperative follow-up.

Morphometric and Biomechanical Comparison of the Scapular Spine and Coracoid Graft in Anterior Shoulder Instability

BACKGROUND

The scapular spine has been described as a relatively new bone graft alternative used in glenoid augmentation. The classic Latarjet procedure, which transfers the coracoid as a graft, is regarded as the gold standard. The comparison of these 2 techniques has not been fully reported.

PURPOSE

To compare the anatomic and biomechanical properties of glenoid augmentation using scapular spine graft or coracoid graft.

STUDY DESIGN

Controlled laboratory study.

METHODS

The study used 20 fresh-frozen human cadaveric shoulders. A 25% anterior glenoid defect was created, and the specimens were divided randomly to receive glenoid augmentation by scapular spine or coracoid grafts. For both procedures, the grafts were secured to the glenoid defect with 2 screws. Morphometric data, including the glenoid articular area, amount of restoration, and graft dimensions, were obtained. A biomechanical test was conducted in a direct-loading scenario. The construct stiffness, cyclic displacement, and ultimate failure of each specimen were collected.

RESULTS

No significant difference was found in glenoid articular restoration between the scapular spine group and the coracoid group (31% vs 33%, respectively; P = .311). Morphometric analysis indicated that coracoid grafts exhibited significantly greater thickness and height than scapular spine grafts. In biomechanical results, the scapular spine group exhibited significantly greater construct stiffness than the coracoid group (206.3 ± 58.8 vs 148.3 ± 76.0 N/mm, respectively; P = .023). The average failure load in the scapular spine group was not significantly higher than that in the coracoid group. No significant differences in cyclic displacement were found between the 2 techniques.

CONCLUSION

In a simulated 25% anterior glenoid bony defect, a scapular spine graft was comparable with the classic Latarjet procedure in restoring the glenoid articular dimension and exhibited superior construct stiffness in a cadaveric model.

CLINICAL RELEVANCE

The scapular spine may serve as an alternative graft choice in glenoid augmentation surgery considering the amount of articular restoration and initial fixation stability.

Free bone grafting improves clinical outcomes in anterior shoulder instability with bone defect: a systematic review and meta-analysis of studies with a minimum of 1-year follow-up

BACKGROUND

Evidence on the efficacy and safety of the free bone grafting in treating anterior shoulder instability is limited. The purpose of this study was to systematically evaluate the clinical and imaging results of free bone grafting in treating anterior shoulder instability with glenoid bone defect and to explore the incidence of complications in clinically relevant subgroups.

METHODS

This systematic review was conducted per PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines. The PubMed, Embase, and Cochrane Library databases were searched up to January 29, 2021, for studies that had reported on free bone grafting in treating anterior shoulder instability with glenoid bone defect with a minimum of 1-year follow-up. Two researchers independently screened studies and extracted data. A random-effects model was used to pool data on clinical function scores, imaging results, and incidence of complications (recurrent instability and non-instability-related complications). Meta-regression analysis was used to evaluate the incidence of complications in different subgroups and investigate the sources of heterogeneity.

RESULTS

A total of 29 studies were included in the meta-analysis, comprising 840 patients (845 shoulders) with average ages ranging from 21 to 34.6 years. Compared with preoperatively, free bone grafting increased the postoperative Rowe score, American Shoulder and Elbow Surgeons score, Constant score, Subjective Shoulder Value, and Oxford Shoulder Instability Score by 53.16, 31.80, 20.81, 38.63, and 4.07 points, respectively, and reduced the visual analog scale pain score by 3 points on average. During the postoperative follow-up period, the rates of return to sport and return to preoperative levels were 84.2% and 73.1%, respectively. The imaging results showed that the free bone healing rate was 98.9% and the incidence of osteoarthritis was 10.9%. The incidence rates of recurrent instability and non-instability-related complications were 3.4% and 5.6%, respectively. Meta-regression analysis showed no evidence of effect modification by the year, follow-up time, proportion of male patients, autograft or allograft, and arthroscopy or open surgery on the incidence of complications. Subgroup analysis showed that the incidence rates of recurrent instability for open surgery, arthroscopy, allograft, autograft, Latarjet revision, and non-bone block revision were 4.1%, 2.3%, 1.5%, 4.4%, 10.3%, and 3.5%, respectively.

CONCLUSION

The application of free bone grafting in treating anterior shoulder instability with glenoid bone defect can effectively improve shoulder joint function and is associated with a high return-to-sport rate and a low overall recurrence rate, but there were some differences in the complications of recurrent instability and non-instability-related complications among the subgroups. Given that these results need to be confirmed via head-to-head comparisons, we recommend that future clinical and biomechanical studies focus on comparing and investigating the advantages and disadvantages of different surgical approaches, thus providing a basis for orthopedic surgeons to make reliable choices.