Summary

Compression of the tendon in SBCR may hinder perfusion of the tendon, and could therefore affect tendon healing in rotator cuff repair. Clinicians should keep in mind that a biological healing process, such as perfusion, is also important as well as footprint restoration in rotator cuff repair.

Abstract

Background

Disturbance of rotator cuff tendon perfusion was proposed in suture bridge configuration repair (SBCR). In vivo assessment of tendon blood supply has been problematic with other modalities. Evaluation of tissue perfusion by indocyanine green (ICG) fluorescence arthroscope has been developed.

Purpose

To verify the hindrance of perfusion in SBCR, this study compared parallel type transosseous repair (PTR) and SBCR by ICG fluorescence camera in rabbits at immediate and 3 days after rotator cuff repair.

Study Design: Controlled laboratory study

Methods

Acute rotator cuff repair was performed on 10 rabbit shoulders. Both shoulders were repaired using either PTR or SBCR. In PTR, simple PTR was performed through two parallel transosseous tunnels created using a micro drill. In SBCR, two additional crisscross transosseous tunnels were added to mimic arthroscopic SBCR. Immediately after the repair, ICG was injected through the ear vein and images were recorded using an ICG fluorescence camera. Tendon perfusion was compared by measuring fluorescence intensity using ImageJ software in both methods. After 3 days of rotator cuff repair, reassessment of ICG fluorescence was performed. In addition, for subsidiary study, comparison of each repair method and normal tendon was done (PTR vs normal tendon and SBCR vs normal tendon). Six rabbits (3 for each comparison) were included.

Results

Immediately after rotator cuff repair, the intensity of ICG fluorescence was weaker in SBCR than PTR in 10 subjects (65.9 ± 47.6 vs 84.3 ± 53.4, p = 0.003). At 3 days after the repair, 8 subjects were included in the analysis, because suture strands failed in 2 subjects in SBCR. The intensity of the fluorescence was still weaker in SBCR compared to PTR (52.5 ± 13.7 vs 60.2 ± 22.7, p = 0.077). Fluorescences intensity compared to normal tendon were 83.2% ± 9.5% in PTR method and 63.2% ± 13.2% in SBCR

Conclusions

Our ICG fluorescence camera system could detect ICG fluorescence in an acute rabbit rotator cuff repair model. SBCR repair showed inferior tendon perfusion immediately after repair. At 3 days after repair, SBCR still showed inferior fluorescence intensity, although it did not reach statistical significance.

Keywords: rotator cuff tear; suture bridge configuration repair; parallel type transosseous repair; tendon ischemia; tendon perfusion; ICG fluorescence arthroscope