Blood supply and vascularity of the glenoid labrum: Its clinical implications

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.

Effects of type II SLAP lesion repair techniques on the vascular supply of the long head of the biceps tendon: a cadaveric injection study

BACKGROUND

One option for the treatment of type 2 superior labral anterior to posterior (SLAP) lesions is arthroscopic repair. However, the fact that the vascular supply of the proximal long head of the biceps tendon (LHBT) arises from the soft tissue near the SLAP repair site must also be considered. The aims of this study were to evaluate the vascular channel of the proximal long head biceps tendon and to compare potential damage to the vascular supply with alternative SLAP techniques.

METHODS

Forty-five fresh cadaveric shoulders were divided into 3 groups: 9 shoulders each for the normal group and the created SLAP group, and 27 shoulders for the repaired SLAP group. SLAP group shoulders were repaired using one of 3 techniques: 2 anchors with simple sutures, 1 anchor with double sutures, or 1 anchor with a horizontal mattress suture. India ink was then injected into the acromial branch of the thoracoacromial artery. The proximal LHBT was resected for a histologic cross-sectional study. The intratendinous vascular distance was measured and compared among the groups.

RESULTS

The vascular supply of the proximal LHBT arises from soft tissue lying anterior and dorsal to the tendon origin. In the normal shoulders, the average intratendinous vascular distance was 16.9 ± 1.5 mm (95% confidence interval: 15.8-18.1). A comparison of nonrepaired SLAPs with each of the repair techniques found that using 2 anchors with simple sutures showed no significant difference in vascular distance (P = .716), whereas the other techniques showed a significant disruption of the blood supply. The differences in vascular distance among the 3 repair techniques were statistically significant (P = .0001).

CONCLUSIONS

The main vascular supply of the proximal LHBT comes from the anterior-dorsal direction. Some SLAP repair techniques can disrupt vascularization; however, the technique using 2 anchors with simple sutures, 1 anchor 3 mm anterior to the anterior border and 1 at the posterior border of the tendon, can preserve the vascularization of the LHBT.

Is Anatomical Healing Essential for Better Clinical Outcome in Type II SLAP Repair? Clinico-Radiological Outcome after Type II SLAP Repair

Background

We hypothesized that anatomical healing in superior labrum anterior to posterior (SLAP) repair is associated with good clinical outcome. The purposes of this study were to assess the failure rate of anatomical healing after arthroscopic repair of SLAP lesions using computed tomography arthrography (CTA), investigate correlation of the rate with clinical outcomes, and identify prognostic factors for anatomical failure following SLAP repair.

Methods

We retrospectively evaluated the outcome of 43 patients at a minimum follow-up of 1 year after arthroscopic surgery for SLAP lesions or SLAP lesions associated with Bankart lesions. Twenty-eight patients underwent isolated SLAP repair and 15 patients underwent Bankart repair with SLAP repair. The anatomical outcome was assessed using CTA at 1 year after surgery. Clinical outcomes including visual analogue scale for pain and satisfaction and Constant score were assessed at the final follow-up. We investigated clinical failure that was defined as stiffness, loss of maximum rotation, deterioration of pain, and/or need for revision of surgery.

Results

Anatomical failure occurred in 32.6% of patients (14/43), whereas 16.3% of patients (7/43) had clinical failure. Clinicoradiological assessment revealed that clinical failure occurred only in 7.1% of patients (1/14) with unhealed SLAP lesions, whereas it occurred in 20.7% of patients (6/29) with healed SLAP lesions. Isolated SLAP repair resulted in a higher risk of anatomical failure (risk ratio, 7.0) than combined SLAP repair (p = 0.015). Nonoverhead activities were associated with higher risk of anatomical failure (risk ratio, 2.9; p = 0.041). Patients above 35 years of age had more risk of anatomical failure (risk ratio, 3.5; p = 0.010). Clinical outcomes significantly improved regardless of anatomical failure (p < 0.001) and were not significantly different between unhealed and healed repairs (all p > 0.05).

Conclusions

Since patients with unhealed SLAP lesions had less clinical failure than patients with healed SLAP lesions, anatomical healing does not seem essential for better clinical outcome of SLAP II repair, especially in patients with higher healing failure risk (isolated SLAP repair, nonoverhead activities, and above 35 years of age). Therefore, we believe the indications of SLAP repair should be narrowed to avoid overtreatment.