Postoperative residual pain is associated with a high magnetic resonance imaging (MRI)-based signal intensity of the repaired supraspinatus tendon.

purposeTo assess patients with and without postoperative residual pain and to compare clinical function and magnetic resonance imaging (MRI) appearance of the repaired supraspinatus tendon between patients with and without pain.

methodsOne-hundred and seventeen patients with supraspinatus tear were included in this study. Visual Analog Scale (VAS) scores for pain were assessed at a follow-up of at least 1 year. Patients with residual shoulder pain were enrolled in the residual pain group (RP group) and patients without pain enrolled in the no pain group (NP group). The American Shoulder and Elbow Surgeons (ASES) shoulder evaluation form, the modified University of California at Los Angeles (UCLA) score and the Fudan University Shoulder Score (FUSS) were also used to evaluate shoulder function. MRI examinations were performed to evaluate rotator cuff integrity according to the Sugaya method, and muscular hypotrophy, fatty infiltration, and signal/noise quotient (SNQ) of the rotator cuff tendon.

resultsThirty-five patients had residual pain (RP group) and 82 patients had no pain (NR group). At the final follow-up, there was a significant difference in ASES (92 ± 8 points vs 76 ± 10 points; p < 0.001), UCLA (32 ± 3 points vs 28 ± 3 points; p < 0.001), FUSS (90 ± 7 points vs 80 ± 9 points; p < 0.001) and strength (9 ± 3 kg vs 6 ± 2 kg; p < 0.001) between the NP group and the RP group, respectively. Postoperative MRI revealed that there was no significant difference in the retear rate (9.8% vs 8.6%; ns), the muscular hypotrophy (ns), and the fatty infiltration index (0.9 ± 0.2 vs 0.9 ± 0.2; ns) between the NP and the RP groups, respectively. The postoperative tendon SNQ of the RP group was significantly higher than that of the NP group (4.6 ± 2.5 vs 3 ± 1.7; p < 0.001). There was a significant association between tendon SNQ and VAS for this cohort ([Formula: see text] = 0.29; p = 0.003).

conclusionPostoperative residual pain is associated with a high MRI signal intensity of the repaired supraspinatus tendon. Since high signal intensity of tendon tissue indicates degenerated tendon tissue quality, it highlighted the necessity of debriding the degenerated rotator cuff tendon tissue. LEVEL OF EVIDENCE: III.