Prevalence of Anterior Inferior Iliac Spine Dysmorphism and Development of a Novel Classification System: An Anatomic Study of 1,797 Cadaveric Specimens.

Purpose: Subspine impingement occurs due to a morphologically abnormal anterior inferior iliac spine (AIIS), capable of causing impingement against the distal femoral neck. The purpose of this investigation was to determine the prevalence of AIIS dysmorphism based on specimen sex, race, and age, while introducing a novel anatomic-based classification system. Methods: A total of 1,797 adult cadaveric specimens (n = 3,594 hemipelvises) were analyzed. AIIS with the potential for subspine impingement (SSI) was recorded in each specimen by two independent authors. Specimens with AIIS dysmorphism were then reexamined to determine SSI subtype using a novel descriptive anatomic classification system. Results: AIIS dysmorphism was present in 6.4% (n = 115 of 1,797 specimens) of specimens and 5.2% (n = 186 of 3,594) of hemipelvises. Dysmorphism was significantly more common in male specimens (p = 0.04) and African-American specimens (p = 0.04). No significant overall difference in prevalence was appreciated based on specimen age (p = 0.89). Subtype classification found that 67% of hemipelvises possessed a columnar type AIIS, 30% were bulbous and 3% hook type. Males possessed a significantly higher prevalence of columnar type AIIS dysmorphism (p < 0.001). No significant overall differences in anatomic classification were appreciated based on race (p = 0.12) or when analyzed based on age (p = 0.34). Conclusion: AIIS dysmorphism was present in 6.4% of the 1,797 cadaveric specimens evaluated. African-American and male specimens possessed significantly higher prevalence of AIIS dysmorphism, with no significant difference based on specimen age. Columnar type AIIS dysmorphism was most common. Anatomic classification was not significantly different based on specimen race or age. Level of Evidence: Case Series, Level IV.

Arthroscopic Iliac Crest Bone Grafting to the Anterior Glenoid.

Failed arthroscopic soft-tissue stabilization and anterior glenoid bone loss have been shown to have high failure rates after standard arthroscopic stabilization techniques. For patients with recurrent glenohumeral instability, the Bristow-Latarjet procedure is currently the standard of care. It is predominantly performed through an open deltopectoral approach but has recently been described arthroscopically. Although providing excellent clinical outcomes, the Bristow-Latarjet procedure violates the subscapularis muscle, has a steep learning curve with a high complication rate, and permanently changes the anterior shoulder anatomy, making any future revision surgery more challenging. We describe a technique for arthroscopic anterior glenoid augmentation using iliac crest bone graft that does not violate the subscapularis, by creating a far anterior-medial portal that traverses superior to the subscapularis and lateral to the conjoint tendon. The graft is passed through this portal and secured with rigid fixation. An arthroscopic Bankart capsulolabral repair is then performed, making the graft extra-articular. A remplissage can easily be added as indicated, allowing this procedure to arthroscopically address all 3 major components of structural instability: glenoid bone loss, capsulolabral tearing, and humeral bone loss.

Scapular neck length and implications for reverse total shoulder arthroplasty: An anatomic study of 442 cadaveric specimens.

PURPOSE: Reverse total shoulder arthroplasty (RTSA) may be used to treat a variety of pathologic shoulder conditions, but complications such as scapular notching continue raise concerns. Variable anatomy surrounding the glenoid may have implications for future RTSA design, but at present the anatomy of the scapular neck in the human population has not been clearly defined. MATERIALS AND METHODS: 442 human scapulae from the Hamann-Todd Osteological Collection were measured for scapular neck length (SNL) and scapular neck angle (SNA). SNL was defined as the distance from the most lateral portion of the infraglenoid tubercle to the most inferolateral portion of the glenoid fossa. The SNA was measured according to Gerber et al. previously. The mean, standard deviation and ranges for SNL and SNA were calculated and compared based on sex and race, and interobserver variability was calculated. RESULTS: The mean SNL was 1.06 cm ± 0.33 cm (0.37-2.43 cm). Males demonstrated a larger SNL (1.08 cm ± 0.33 cm) than females (1.01 cm ± 0.32 cm) (P < 0.12), and Caucasians (1.09 cm ± 0.33 cm) demonstrated a significantly larger SNL than African-Americans (1.00 cm ± 0.32) (P < 0.01). The mean SNA was 106.7° ± 11.0° (76.9-139.4°). No significant correlation was found between SNL and SNA (Pearson Correlation Coefficient = 0.018) (P < 0.702). CONCLUSION: Scapular neck length and SNA vary widely within the population but there appears to be a tendency towards increased SNL in males and Caucasians. CLINICAL RELEVANCE: The anatomy of the scapular neck may have significant implications for RTSA design, surgical planning, and reduction of associated complications.