The glenoid labrum: does labral lesion location matter?

Superior and Anterior Glenoid Labral Tears Are Associated With Increased Neurofilament Concentration

BACKGROUND

Pain is a common presentation after glenohumeral labral injuries. However, the source of that pain is undetermined.

PURPOSE/HYPOTHESIS

We aimed to determine if there is a differential expression of nerve fibers around the glenoid labrum and if torn labra have increased neuronal expression compared with untorn labra (rotator cuff repair labra). We hypothesized that the superior labrum would have a higher concentration of neurofilament than would the rest of the labrum and that the concentration of neurofilament would increase at the site of a labral tear.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Seven labra were sampled at the 3-, 5-, 9-, and 12-o'clock positions during total shoulder arthroplasty. Samples were also collected at the 3-, 5-, and 12-o'clock positions during rotator cuff repair (16 labra), anterior labral repair (6 labra), type II superior labral anterior to posterior (SLAP) repair (4 labra), and capsular release for idiopathic capsulitis (5 labra). Sections were immunostained with antibodies to neurofilament, a specific neuronal marker that is used to identify central and peripheral nerve fibers, and the concentration and intensity of immunostained-positive cells assessed.

RESULTS

The concentration of neurofilament staining was similar in the superior, anterior, posterior, and inferior glenoid labrum in untorn labra (8 neurofilament expressing cells per square millimeter; P = .3). Torn labra exhibited a 3- to 4-fold increase in neuronal expression, which was isolated to the location of the tear in SLAP (P = .09) and anterior labral tears (P = .02). The concentration of neurofilament expressing cells in torn glenoid labrum samples was comparable that in with the glenoid labrum of adhesive capsulitis samples (P = .7).

CONCLUSION

This study supports the hypothesis that after a tear of the anterior or superior labrum the labrum in that region becomes populated with new nerves fibers and that these fibers may be responsible for the pain noted by patients with superior (SLAP) and/or anterior labral (Bankart) tears.

CLINICAL RELEVANCE

This study suggests that neural infiltration contributes to the pain experienced by patients with labral tears. It may help with patient education and direct future management of labral lesions.

Postoperative Pain and Paresthesia in Labral Repairs of the Shoulder: Location Does Matter

Background:

Favorable outcomes have been reported regarding postoperative shoulder pain and function after repair of anteroinferior (Bankart) glenohumeral labral tears. However, the outcomes of patients after repair of isolated superior labral anterior-posterior (SLAP) tears are a contentious topic. The authors have also anecdotally noted that patients evaluated with labral tears complained of numbness and tingling in their ipsilateral hand.

Purpose:

To determine if there is a difference in the temporal outcomes of shoulder pain and hand paresthesia in patients with SLAP tears versus Bankart tears after arthroscopic repair.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Included were 66 consecutive patients who underwent arthroscopic labral repair at a single institution between August 2018 and February 2021. The prevalence and magnitude of shoulder pain as well as numbness and tingling of the hand were assessed using questions from the L’Insalata Shoulder Questionnaire and the Boston Carpal Tunnel Questionnaire preoperatively and at 1 week, 6 weeks, 12 weeks, and 6 months after surgery.

Results:

Preoperatively, patients with SLAP lesions reported a higher prevalence of shoulder pain during sleep compared with those with Bankart tears (P < .05). Postoperatively, patients who underwent SLAP repair reported a larger proportion and more severe magnitude of shoulder pain during rest, overhead activities, and sleep compared with those who underwent Bankart repair (P < .05). Only patients who underwent Bankart repair reported improvements in the prevalence and magnitude of their shoulder pain during rest, overhead activities, and sleep by 6 months postoperatively compared with preoperative levels (P < .05). Preoperatively, 30% of patients with Bankart repairs and 40% of patients with SLAP repairs reported hand tingling, while 35% and 50%, respectively, reported hand numbness. The prevalence and magnitude of hand tingling and numbness were not significantly different between groups at any time point.

Conclusion:

Study results indicated that patients who underwent SLAP repair experienced worse shoulder pain outcomes compared with those who underwent Bankart repair using the same anchor and surgical technique. Only patients who underwent Bankart repair reported improvements in their hand numbness after surgery. Therefore, labral tear location does matter with respect to shoulder pain and hand numbness.

Arthroscopic repair of inferior glenoid labrum tears (Down Under lesions) produces similar outcomes to other glenoid tears

PURPOSE

Inferior glenoid labral tears are an uncommon but distinct shoulder injury. Only a small number of studies have reported outcomes following arthroscopic repair. The aim of the current study was to report minimum 2-year outcomes following inferior labral repair and to compare outcomes and risk factors associated with the injury to non-inferior labral tears. Whether preoperative MRI or MRA identified inferior labral tears was also assessed.

METHODS

A prospective study of 162 consecutive patients undergoing arthroscopic glenoid labral repair, excluding isolated superior labral tears, was conducted. Of the 130 patients available for follow-up, 18 (13.7%) had an inferior labral tear ("Down Under lesion"), the remainder had anterior, posterior or mixed anterior/posterior lesions that did not include the inferior pole. Mean follow-up time for the Down Under group was 44 months (SD 10, range 27-57), and 30 months (SD 14, range 4-60) for the non-Down Under group. Postoperative outcomes included the Oxford Shoulder Instability Score and recurrent instability. Associations between Down Under lesions and injury mechanism, instability at presentation, recurrent instability and family history were assessed with multivariable logistic regression. Preoperative MRI or MRA reports by radiologists were examined to determine if Down Under lesions were identified.

RESULTS

Oxford Shoulder Instability Scores indicated that most patients in both groups had little pain or shoulder problems postoperatively (average Oxford Score 41; 48 = no symptoms). Oxford Scores were not significantly different between the Down Under and non-Down Under groups. Four patients (22.2%) in the Down Under group had recurring symptoms (pain and instability) compared to 12 (10.6%) in the non-Down Under group; this difference was not statistically significant (adjusted OR 1.09, 95% CI 0.19,4.77). Family history of shoulder instability was positively associated with a Down Under lesion (adjusted OR 5.0, 95%CI 1.51,16.7). MRI or MRA identified 52.9% of Down Under lesions.

CONCLUSION

Down Under lesions were an infrequent type of glenoid labral injury, yet postoperative outcomes were similar to other labral tears. Patients with Down Under lesions had a significant risk factor due to family history of shoulder instability. MRI and MRA could not reliably identify Down Under lesions.

LEVEL OF EVIDENCE

Level III.