What did the study look at?
The glenoid labrum is a ring of fibrocartilage around the rim of the shoulder socket (glenoid). Traumatic shoulder dislocations are the main cause of labral tears, which are usually repaired with suture anchors placed in the bone. The authors note that poor anchor placement has been linked with recurrent instability, yet the best anchor position has not been precisely defined. The aim of the study was to describe the macroscopic footprint of the labrum in order to define the ideal anchor location.
How was it done?
- Twenty-two shoulders from 11 cadavers were dissected; the mean age was 67 years (57-78). None had a history of significant trauma or upper limb surgery.
- Three specimens with severe arthritis were unsuitable and excluded, so measurements were made in 19 specimens.
- A clock face was placed on the glenoid, with 12 o'clock at the top and 6 o'clock at the bottom, and the distance between the edge of the labrum and the bony rim was measured with microcalipers at 12 points one hour apart.
- Measurements were made by 3 experienced orthopaedic surgeons in a double-blind set-up.
What did it find?
- According to the results table, mean distances were 4.86 mm at 12 o'clock, 4.20 mm at 1, 4.41 mm at 2, 5.23 mm at 3, 5.52 mm at 4, 6.25 mm at 5, 6.10 mm at 6, 5.98 mm at 7, 5.71 mm at 8, 5.52 mm at 9, 5.14 mm at 10 and 5.52 mm at 11 o'clock.
- There was a trend towards differences between positions, but it was not statistically significant. The largest differences were between 6 o'clock and the 11, 12, 1 and 2 o'clock positions.
- The anterior part of the labrum was completely absent in 29.3% of specimens. The upper labrum had a meniscus-like pattern with a loose attachment, while the lower labrum was rounded and fibrous.
- Inter- and intra-observer variability did not exceed 0.1 mm.
Note: the article's abstract gives different values from the results table for some positions (for example 4.1 mm at 12 o'clock); the figures above are those in the results section.
The authors' conclusion
The authors conclude that the labrum attaches to the glenoid at a variable distance from the bony rim, and that the position of the labrum relative to the bony rim should be considered when placing sutures in labral repair. They suggest that the most important step in addressing joint laxity is correct suture placement along the front and lower parts of the labrum, and that anatomy may differ from person to person.
Limitations
The authors note that the assessment was made by open dissection without arthroscopic evaluation, and that the labral edge may look different arthroscopically. Other measurements of glenoid shape were not taken, so no associations with glenoid morphology could be made.
Reference
Şimşek ME, Akkaya M, Gürsoy S, Kaya Ö, Apaydın N, Bozkurt M. (2019). Macroscopic footprint of the glenoid labrum. Anatomy (Turkish Society of Anatomy and Clinical Anatomy), 13(3), 168–173. Licence: CC BY-NC-ND 3.0.
DOI: 10.2399/ana.19.088
Free full text: dergipark.org.tr (PDF)
This article summarises a published scientific paper for general information; it does not replace an examination or a personal medical assessment. Please consult your doctor about your symptoms.
