CT-based and morphological comparison of glenoid inclination and version angles and mineralisation distribution in human body donors.

BACKGROUND: For optimal prosthetic anchoring in omarthritis surgery, a differentiated knowledge on the mineralisation distribution of the glenoid is important. However, database on the mineralisation of diseased joints and potential relations with glenoid angles is limited. METHODS: Shoulder specimens from ten female and nine male body donors with an average age of 81.5 years were investigated. Using 3D-CT-multiplanar reconstruction, glenoid inclination and retroversion angles were measured, and osteoarthritis signs graded. Computed Tomography-Osteoabsorptiometry (CT-OAM) is an established method to determine the subchondral bone plate mineralisation, which has been demonstrated to serve as marker for the long-term loading history of joints. Based on mineralisation distribution mappings of healthy shoulder specimens, physiological and different CT-OAM patterns were compared with glenoid angles. RESULTS: Osteoarthritis grades were 0-I in 52.6% of the 3D-CT-scans, grades II-III in 34.3%, and grade IV in 13.2%, with in females twice as frequently (45%) higher grades (III, IV) than in males (22%, III). The average inclination angle was 8.4°. In glenoids with inclination ≤10°, mineralisation was predominantly centrally distributed and tended to shift more cranially when the inclination raised to > 10°. The average retroversion angle was - 5.2°. A dorsally enhanced mineralisation distribution was found in glenoids with versions from - 15.9° to + 1.7°. A predominantly centrally distributed mineralisation was accompanied by a narrower range of retroversion angles between - 10° to - 0.4°. CONCLUSIONS: This study is one of the first to combine CT-based analyses of glenoid angles and mineralisation distribution in an elderly population. The data set is limited to 19 individuals, however, indicates that superior inclination between 0° and 10°-15°, and dorsal version ranging between - 9° to - 3° may be predominantly associated with anterior and central mineralisation patterns previously classified as physiological for the shoulder joint. The current basic research findings may serve as basic data set for future studies addressing the glenoid geometry for treatment planning in omarthritis.

Glenoid morphology in light of anatomical and reverse total shoulder arthroplasty: a dissection- and 3D-CT-based study in male and female body donors.

BACKGROUND: Placement of the glenoid baseplate is of paramount importance for the outcome of anatomical and reverse total shoulder arthroplasty. However, the database around glenoid size is poor, particularly regarding small scapulae, for example, in women and smaller individuals, and is derived from different methodological approaches. In this multimodality cadaver study, we systematically examined the glenoid using morphological and 3D-CT measurements. METHODS: Measurements of the glenoid and drill hole tunnel length for superior baseplate screw placement were recorded to define size of the glenoid and the distance to the scapular notch on cadaveric specimens. Glenoid angles were determined on both, 3D-CT-scans of the thoraxes using the Friedman method and on subsequently isolated scapulae from 18 male and female donors (average 84 years, range 60-98 years). RESULTS: Mean glenoid height was 36.6 mm ± 3.6, and width 27.8 mm ± 3.1 with a significant sex dimorphism (p ≤ 0.001): in males, glenoid height 39.5 mm ± 3.5, and width 30.3 mm ± 3.3, and in females, glenoid height 34.8 mm ± 2.2, and width 26.2 mm ± 1.6. The average distance from the superior screw entry to its exit in the scapular notch measured by calliper was 27.2 mm ± 6.0 with a sex difference: in males, 29.4 mm ± 5.7, and in females, 25.8 mm ± 5.9 mm with a minimum recorded distance of 15 mm. Measured by CT, the mean inclination angle for male and female donors combined was 13.0° ± 7.0, and the ante-/retroversion angle -1.0° ± 4.0°. CONCLUSION: This study is one of the first to combine dissection, including drill holes, with anatomical measurements and radiological data. In some women and smaller individuals, smaller baseplates should be selected. The published safe zone of 20 mm is generally feasible for superior screw placement, however, in small patients this distance may be substantially shorter than expected and start as of 13 and 15 mm, respectively. No correlation between glenoid height or width with the length of our drilling canal towards the scapular notch was found. Preoperative CT-based treatment planning to determine version and inclination angles is recommended.

The upper limb of Australopithecus sediba.

The evolution of the human upper limb involved a change in function from its use for both locomotion and prehension (as in apes) to a predominantly prehensile and manipulative role. Well-preserved forelimb remains of 1.98-million-year-old Australopithecus sediba from Malapa, South Africa, contribute to our understanding of this evolutionary transition. Whereas other aspects of their postcranial anatomy evince mosaic combinations of primitive (australopith-like) and derived (Homo-like) features, the upper limbs (excluding the hand and wrist) of the Malapa hominins are predominantly primitive and suggest the retention of substantial climbing and suspensory ability. The use of the forelimb primarily for prehension and manipulation appears to arise later, likely with the emergence of Homo erectus.