A shallow morphology of the intertubercular groove is associated with medial and bilateral but not lateral pulley lesions

Abstract

Purpose: To investigate the influence of intertubercular groove (IG) morphology on the development of different types of biceps reflection pulley (BRP) injuries.

Methods: A consecutive cohort of 221 patients with ventral shoulder pain and a preoperative diagnosis suspecting BRP injury, who underwent arthroscopy, was retrospectively reviewed. The presence or absence as well as type of pulley injury (medial, lateral or bilateral) was confirmed arthroscopically. The intertubercular groove was evaluated on MRIs after triplanar reconstruction of the axial plane. IG depth, width, medial wall angle (MWA), lateral wall angle (LWA) and total opening angle (TOA) were measured. IG depth and width were expressed in relation to the humeral head diameter. Measurements were performed by two clinicians independently and averaged.

Results: Of 166 included patients 43 had bilateral, 65 medial and 38 lateral BRP lesions. 20 patients had intact BRPs and represented the control group. The intra-class correlation coefficient of measurements was 0.843-0.955. Patients with a medial or bilateral BRP injury had a flatter MWA (38.8° or 40.0° vs. 47.9°, p < 0.001), wider TOA (96.1° or 96.6° vs. 82.6°, p < 0.001), greater width (12.5 or 12.3 vs. 10.8 mm, p = 0.013) and shallower depth (5.5 or 5.4 vs. 6.2 mm, p < 0.001) than the control group. Conversely, the IG morphology of those with lateral BRP injuries did not differ significantly from the control group. The odds ratio for a medial or bilateral BRP injury when the TOA exceeded 95° was 6.8 (95% confidence interval 3.04-15.2).

Conclusion: A dysplastic type of IG morphology with a wide TOA, flat MWA, decreased depth and increased width is associated with the presence of medial and bilateral BRP injuries. A TOA of > 95° increases the likelihood of a medial or bilateral BRP injury 6.8-fold. Lateral BRP injuries are not associated with dysplastic IG morphology. Concomitant LHBT surgery may, therefore, not always be necessary during isolated supraspinatus tendon repair.

Level of evidence: Level III.

Keywords: Biceps reflection pulley; Dysplastic; Influencing factor; Intertubercular groove morphology; Rotator cuff.

Fig. 1

After applying the exclusion criteria patients were assigned to one of 4 subgroups based on the findings at arthroscopy

Fig. 2

Arthroscopic images of a medial BRP injury around the long head of biceps tendon (LHBT). The medial part (a) shows a tear of the superior glenohumeral ligament (SGHL) and a tear of the cranial subscapularis tendon (SSC). The lateral BRP (b), including the coracohumeral ligament (CHL) and supraspinatus tendon (SSP), is intact

Fig. 3

Arthroscopic images of a lateral BRP injury around the long head of biceps tendon (LHBT). The medial part (a), comprising the subscapularis tendon (SSC) and superior glenohumeral ligament (SGHL), is intact. Laterally (b) the coracohumeral ligament is torn and a partial articular sided avulsion of the supraspinatus tendon (SSP) is visible

Fig. 4

Arthroscopic images of a bilateral BRP injury around the long head of biceps tendon (LHBT). The medial part (a) shows a tear of the superior glenohumeral ligament (SGHL) and partial avulsion of the cranial subscapularis tendon (SSC). The lateral part (b) shows a tear of the coracohumeral ligament (CHL)

Fig. 5

Arthroscopic images of an intact BRP around the long head of biceps tendon (LHBT). Medially (a) the superior glenohumeral ligament (SGHL) and subscapularis tendon (SSC) are intact. Laterally (b) the coracohumeral ligament (CHL) and supraspinatus tendon (SSP) are intact

Fig. 6

The axial plane was reconstructed in 3 planes, to be at the level of and in line with the highest point of each tuberosity, whilst being aligned at 90° to the floor of the IG

Fig. 7

After triplanar reconstruction of the axial plane, a line was drawn between the apex of both the medial and lateral IG walls (corresponding to the lesser and greater tuberosities). A line parallel to this was then placed on the deepest point of the IG (blue dotted lines). The TOA (b) was then measured between the 3 landmarks (red crosses). Then the LWA (a) and MWA (c) were determined. The IG depth (d) was measured between the parallel lines and width (e) between the IG walls

Fig. 8

Scatter plot of the correlation between patient age and the TOA. The corresponding Pearson’s coefficient of − 0.12 showed a weak negative correlation (p = n.s.)

Fig. 9

Examples of a dysplastic open and shallow IG from a patient with a bilateral BRP lesion (a) and an IG from a patient without a BRP lesion (b)