The acromiohumeral distance and the subacromial clearance are correlated to the glenoid version

Can the presence of SLAP-5 lesions be predicted by using the critical shoulder angle in traumatic anterior shoulder instability?

OBJECTIVE

Although SLAP-5 lesions are associated with recurrent dislocations, their causes and pathomechanisms have not been fully elucidated. This study aimed to investigate the association between SLAP-5 lesions and scapular morphology in traumatic anterior shoulder instability (ASI). We hypothesized that there may be a relationship between SLAP-5 lesions and scapular morphology in traumatic ASI patients.

MATERIALS AND METHODS

The study included 74 patients with isolated Bankart lesions and 69 with SLAP-5 lesions who underwent arthroscopic labral repair for ASI. Critical shoulder angle (CSA) was measured on the roentgenograms, while glenoid inclination (GI) and glenoid version (GV) were measured on magnetic resonance imaging (MRI) by two observers in two separate sessions blinded to each other. Both groups were compared in terms of CSA, GI, and GV.

RESULTS

The mean ages of Bankart and SLAP-5 patients were 28.4±9.1 and 27.9±7.7 (P=0.89), respectively; their mean CSA values were 33.1°±2.6° and 28.2°±2.4°, respectively (P<0.001). The ROC analysis's cut-off value was 30.5°, with 75.0% sensitivity and 76.7% specificity (AUC = 0.830). SLAP-5 lesions were more common on the dominant side than isolated Bankart lesions (P=0.021), but no difference was found between the groups in terms of GI and GV (P=0.334, P=0.081, respectively).

CONCLUSIONS

In ASI, low CSA values appeared to be related to SLAP-5 lesions, and the cut-off value of CSA for SLAP lesion formation was 30.5° with 75.0% sensitivity and 76.7% specificity. Scapula morphology may be related to the SLAP-5 lesions, and CSA can be used as an additional parameter in provocative diagnostic tests and medical imaging techniques for the detection of SLAP lesions accompanying Bankart lesions.

LEVEL OF EVIDENCE

III retrospective case-control study.

Diagnostic Value of Acromiohumeral Distance in Rotator Cuff Pathology: Implications for Advanced-Practice Physiotherapists

Purpose: The primary purpose of this study was to examine the inter-tester reliability and criterion validity of reduced acromiohumeral distance (AHD; <6 mm) visualized on plain radiographs in detecting rotator cuff (RC) pathology. The secondary objective was to examine the relationship between this radiographic feature and patient demographics and clinical examination. Method: This was a diagnostic study of patients seen in a tertiary care centre. Two advanced-practice physiotherapists measured AHD in two radiographic views. MRI was used as the gold standard. Results: A total of 150 consecutive patients (mean age 59 [SD 11] y, 57 women, 93 men) were included. AHD less than 6 millimetres was highly specific in both views for the presence of tear (99%), tear size (96%-98%), and fatty infiltration in the supraspinatus and infraspinatus muscles (93%-96%). The absence of AHD less than 6 millimetres was associated with a lack of advanced fatty infiltration in the supraspinatus and infraspinatus muscles (92%-100%). Sensitivity values were low for the presence and size of RC tear (21%-55%). We found a statistically significant positive association between the AHD categories and clinically observed muscle wasting and weakness of the RC muscles (p < 0.05). Conclusions: AHD less than 6 millimetres was reliably measured in plain radiographs and was strongly associated with important clinical and imaging features of advanced RC pathology; this may assist with clinical decision making by allowing judicious use of more costly investigations and referral for surgery.

Small anteroposterior inclination of the acromion is a predictor for posterior glenohumeral erosion (B2 or C)

BACKGROUND

Anatomic factors associated with static posterior translation of the humeral head with or without glenohumeral osteoarthritis are unknown. We tested the hypothesis that there is an association between glenoid wear, glenoid version, and/or anteroposterior acromial tilt.

METHODS

Ninety-nine patients with glenohumeral joint degeneration involving advanced glenoid cartilage wear and/or rotator cuff disease scheduled for anatomic or reverse total shoulder replacement underwent standardized conventional radiographic and computed tomographic shoulder imaging. Measurements included glenoid version, humeral torsion, posterior acromial slope, and critical shoulder angle. The glenoid shape was classified according to Walch et al, and the integrity of the rotator cuff was assessed.

RESULTS

Patients with glenoid type B2 or C had a median of 4° more glenoid retroversion (P = .022), a 5° less steep acromion (posterior acromial slope, 61° vs 56°; P = .004), and a higher combined score (glenoid version minus slope; odds ratio, 0.93 [95% confidence interval, 0.89-0.97]; P < .001; cutoff, -27°) than those with type A or B1. When the rotator cuff was torn, osteoarthritic changes were milder than when the cuff was intact (eg, P < .001 for supraspinatus).

CONCLUSION

The study's hypothesis that the bony anatomy of the scapula and in particular the acromion is correlated with the type of glenoid wear was confirmed. Both a more horizontal acromial orientation in the sagittal plane and increased posterior glenoid version are found in osteoarthritis of the shoulder associated with eccentric, posterior glenoid wear. Tears of the rotator cuff are significantly associated with concentric osteoarthritis of the glenoid.