Morphometric Study on Bicipital Groove among South Indian Population

Diagnostic value of the hourglass biceps test for the detection of intra-articular long head of the biceps hypertrophy

Background

Shoulder surgeons performing tenodesis note a great variability in morphology of the proximal biceps. The hourglass biceps test measures the integrity of the intra-articular biceps tendon. The hourglass maneuver (HM) is positive when there is a passive flexion deficit compared to the contralateral shoulder in a relaxed patient in the supine position.

Hypothesis

Preoperative HM is correlated with an increased width of the biceps portion resected during tenodesis.

Methods

This prospective study evaluated all patients (N = 58) who underwent biceps tenodesis between January and September 2019. Two groups of patients were compared: group 1 (n = 20) had a positive HM and group 2 had a negative HM (n = 38). The smallest (s) and largest (L) width of the tendon were measured intraoperatively, and the L/s ratio was calculated. The HM was then evaluated as a diagnostic test by creating a contingency table and determining the sensitivity and specificity of the test for different L/s ratios. A receiver operating characteristic curve was created and the area under the curve (AUC) was calculated.

Results

A nonsignificant difference was found between the mean largest biceps width in group 1 compared to group 2 (11.65 mm [range: 5-21] vs. 9.71 mm [range: 6-20], respectively; P < .05). The AUC was 0.81; the sensitivity was 68.9% and specificity, 80.8%.

Conclusion

Preoperative positivity of the HM is linked to the increased width of the biceps portion resected during tenodesis. The hourglass biceps test should be predictive of intraoperative hourglass biceps according to our definition.

Dimensional analysis of the bicipital groove and its associated pathology in a South African population

The bicipital groove (BG) forms an indentation between the greater and lesser humeral tubercles and lodges the long head of biceps brachii tendon (LHBBT) along with the ascending branch of the circumflex humeral artery. This study aimed to determine the dimensions (length, width, depth) of the BG in a select South African population. The dimensions of the BG in one hundred and sixty (n = 160; Right: 80; Left: 80, Male: 100; Female: 60) unpaired dry bone humerii were measured with a digital caliper (Linear Tools 2012, 0-150 mm, LIN 86500963) and was analyzed using SPSS (V25). Results: Bicipital groove dimensions: (a) Length (mm): Right 66.64 ± 9.06, Left 68.31 ± 11.52; Male 67.44 ± 9.12, Female 67.53 ± 12.25; (b) Width (mm): Right 8.98 ± 1.49, Left 9.27 ± 1.30; Male 9.18 ± 1.45, Female 9.05 ± 1.31; (c) Depth (mm): Right 7.73 ± 1.31, Left 7.20 ± 1.18; Male 7.43 ± 1.29, Female 7.53 ± 1.24. The mean BG length observed in this study disagreed with previous studies where smaller lengths were reported. In addition, the comparison of the mean BG depth in this study also revealed a statistically significant difference which may suggest that increased depth in the BG is a common finding in right side of BG specimens. This finding was unique as BG depth is associated with biceps tendon pathology and augments South African shoulder-related literature. Since biceps tendon pathology is associated with decreased biceps activity and pain, investigation of the BG may provide useful data to evaluate individuals with potential abnormality of the bicep tendon. It may also be used as a landmark for humeral head replacement in the treatment of proximal humerus fractures.

An anthropometric evaluation of the scapula, with emphasis on the coracoid process and glenoid fossa in a South African population

The exact dimensions of the scapula, including the coracoid process and glenoid fossa, are fundamental in the patho-mechanics of the glenohumeral joint (GHJ); as these structures act as initiators of shoulder movement. The aim of the study was to evaluate the anthropometric parameters of the GHJ, with emphasis on the coracoid process and glenoid fossa. The morphometric (Linear Tools 2012, 0-150mm, LIN 86500963) and morphological parameters of a total of one hundred and sixty-four (n = 164) dry bone scapulae [Right (R): 80; Left (L): 84, Male (M): 68; Female (F): 96] were recorded. Results: (i) Shape of glenoid fossa: Type 1: (R) 16.5%, (L) 11.0%; Male (M) 20.1%, Female (F) 7.3%; Type 2: (R) 14.0%, (L) 15.2%; (M) 18.3%, (F) 11.0%; Type 3: (R) 18.3%, (L) 25.0%; (M) 27.4%, (F) 15.9%. (ii) Notch type: Type 1: (R) 1.7%, (L) 7.3%; (M) 6.7%, (F) 2.4%; Type 2: (R) 47.0%, (L) 43.9%; (M) 59.2%, (F) 31.7%. (iii) Vertical diameter of glenoid fossa (VD) (mm): (R) 35.2 ± 3.1, (L) 34.9 ± 3.0; (M) 35.3 ± 3.2, (F) 34.6 ± 2.8. (iv) Horizontal diameter 1 (HD1) of glenoid fossa (mm): (R) 18.4 ± 3.3, (L) 17.5 ± 2.9; (M) 18.2 ± 3.3, (F) 17.4 ± 2.6. (v) Horizontal diameter 2 (HD2) of glenoid fossa (mm): (R) 24.5 ± 2.9, (L) 23.6 ± 2.6; (M) 24.2 ± 2.7, (F) 23.7 ± 2.8. (vi) Length of coracoid process (CL) (mm): (R) 41.7 ± 4.7, (L) 41.5 ± 4.9; (M) 42.1 ± 4.7, (F) 40.7 ± 4.8. (vii) Width of coracoid process (CW) (mm): (R) 13.3 ± 1.9, (L) 14.2 ± 11.9; (M) 13.1 ± 1.9, (F) 15.1 ± 14.5. (viii) Coracoglenoid distance (CGD) (mm): (R) 27.4 ± 8.3, (L) 28.2 ± 3.5; (M) 28.2 ± 7.4, (F) 27.0 ± 3.4. In the present study, Type 3 (oval) was observed to be the predominant glenoid fossa shape with a higher incidence in male individuals and on the right side. Although only notch Types 1 (without a notch) and 2 (with one notch) were observed in this study, Type 2 (one notch) was the most prevalent, presenting with a significant p-value (p = 0.019), suggesting that notch Type 1 (without a notch) and 2 (with one notch) are common findings in the right and left side of individuals. The findings observed in this study may provide knowledge regarding the role of the coracoid parameters in etiology of subcoracoid impingement while knowledge on the glenoid fossa parameters and variations are essential for evaluation in shoulder arthroplasty for glenoid fractures and anterior dislocations, and for glenoid prosthesis designs for the South African population.